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Description of designengine

Marine diesel from MAN - Burmeister and Wein (MAN B&W Diesel A/S), brand L50MC/MCE - two-stroke single-action, reversible, crosshead with gas turbine supercharging (with constant gas pressure in front of the turbine) with built-in thrust bearing, in-line cylinder arrangement , vertical.

Cylinder diameter - 500 mm; piston stroke - 1620mm; the purge system is direct-flow valve.

Effective diesel power: Ne = 1214 kW

Rated rotation speed: n n = 141 min -1.

Effective specific consumption fuel at nominal mode g e = 0.170 kg/kW h.

Overall dimensions of the diesel engine:

Length (on the fundamental frame), mm 6171

Width (across the fundamental frame), mm 3770

Height, mm. 10650

Weight, t 273

A cross section of the main engine is shown in Fig. 1.1. The coolant is fresh water (in a closed system). The temperature of fresh water at the outlet of the diesel engine at steady state operation is 80...82°C. The temperature difference at the inlet and outlet of the diesel engine is no more than 8...12°C.

The temperature of the lubricating oil at the diesel inlet is 40...50 °C, at the diesel outlet 50...60 °C.

Average pressure: Indicator - 2.032 mPa; Effective -1.9 mPa; Maximum combustion pressure - 14.2 MPa; Purge air pressure is 0.33 MPa.

Assigned resource until overhaul- not less than 120000h. Diesel service life is at least 25 years.

The cylinder cover is made of steel. An exhaust valve is attached to the central hole using four pins.

In addition, the cover is equipped with drillings for nozzles. Other drillings are for indicator, safety and start valves.

The top of the cylinder liner is surrounded by a cooling jacket installed between the cylinder cover and the cylinder block. The cylinder sleeve is secured to the top of the block by a cap and is centered in the bottom hole inside the block. The tightness against leakage of cooling water and purge air is ensured by four rubber rings inserted into the grooves of the cylinder liner. On the lower part of the cylinder liner between the cavities of cooling water and purge air there are 8 holes for fittings for supplying lubricating oil to the cylinder.

The central part of the crosshead is connected to the head bearing journal. The cross beam has a hole for the piston rod. The head bearing is equipped with liners that are filled with babbitt.

The crosshead is equipped with drillings for supplying oil, which flows through a telescopic tube partly to cool the piston, partly to lubricate the head bearing and guide shoes, and also through a hole in the connecting rod to lubricate the crank bearing. The central hole and two sliding surfaces of the crosshead shoes are filled with babbitt.

The crankshaft is semi-composite. The frame bearings receive oil from the main lube oil line. The thrust bearing serves to transmit the maximum thrust of the screw through the screw shaft and intermediate shafts. The thrust bearing is installed in the aft section of the fundamental frame. Lubricating oil for lubrication thrust bearing comes from the pressure lubrication system.

The camshaft consists of several sections. Sections are connected using flange connections.

Each engine cylinder is equipped with a separate high-pressure fuel pump (HPFP). The fuel pump operates from a cam washer on the camshaft. The pressure is transmitted through the pusher to the fuel pump plunger, which is connected through a high-pressure tube and distribution box to the injectors mounted on the cylinder cover. Fuel pumps are spool type; injectors - with central fuel supply.

Air enters the engine from two turbochargers. The TK turbine wheel is driven by exhaust gases. A compressor wheel is installed on the same shaft as the turbine wheel, which takes air from the engine room and supplies air to the cooler. A moisture separator is installed on the cooler body. From the cooler, air enters the receiver through open non-return valves located inside the charge air receiver. Auxiliary blowers are installed at both ends of the receiver, which supply air past the coolers in the receiver with the non-return valves closed.

Rice. Cross section of the L50MC/MCE engine

The engine cylinder section consists of several cylinder blocks, which are attached to the fundamental frame and crankcase with anchors. The blocks are connected to each other along vertical planes. The block contains cylinder liners.

The piston consists of two main parts: the head and the skirt. The piston head is bolted to the top ring of the piston rod. The piston skirt is attached to the head with 18 bolts.

The piston rod has a through drilling for the cooling oil pipe. The latter is attached to the upper part of the piston rod. Then the oil flows through a telescopic tube to the crosshead, passes through the drilling in the base of the piston rod and the piston rod to the piston head. Then the oil flows through the drilling to the supporting part of the piston head to the outlet pipe of the piston rod and then to the drain. The rod is attached to the crosshead by four bolts passing through the base of the piston rod.

Selection of fuel and oil with analysis of the influence of their characteristics on rAbot

Types of fuels and oils used

Fuels used

IN last years There has been a steady trend of deterioration in the quality of marine heavy fuels, associated with deeper oil refining and an increase in the share of heavy residual fractions in the fuel.

Marine vessels use three main groups of fuels: low-viscosity, medium-viscosity and high-viscosity. From low-viscosity domestic fuels Distillate diesel fuel L is most widely used on ships; it does not contain mechanical impurities, water, hydrogen sulfide, water-soluble acids and alkalis. The limit sulfur value for this fuel is 0.5%. However, for diesel fuels produced from high-sulfur oil, according to technical conditions, a sulfur content of up to 1% or higher is allowed.

Medium-viscosity fuels used in marine diesel engines include diesel fuel - motor fuel and F5 grade naval fuel oil.

The group of high-viscosity fuels includes the following brands of fuel: motor fuel grades DM, naval fuel oil M-0.9; M-1.5; M-2.0; E-4.0; E-5.0; F-12. Until recently, the main criterion when ordering was its viscosity, by the value of which we roughly judge other important characteristics of the fuel: density, coking ability, etc.

Fuel viscosity is one of the main characteristics of heavy fuels, since fuel combustion processes, operational reliability and durability of fuel equipment, and the ability to use fuel at low temperatures depend on it. During the preparation of fuel, the required viscosity is ensured by heating it, since the quality of atomization and the efficiency of its combustion in a diesel cylinder depend on this parameter. The viscosity limit of the injected fuel is regulated by the engine maintenance instructions. The rate of sedimentation of mechanical impurities, as well as the ability of the fuel to peel off water, largely depends on viscosity. When the viscosity of the fuel increases by a factor of 2, all other conditions being equal, the sedimentation time of particles also increases by a factor of two. The viscosity of the fuel in the settling tank is reduced by heating it. For open systems, the fuel in the tank can be heated to a temperature no less than 15°C below its flash point and no higher than 90°C. Heating above 90°C is not allowed, since in this case the boiling point of water can easily be reached. It should be noted that emulsion water varies in viscosity. With an emulsion water content of 10%, the viscosity can increase by 15-20%.

Density characterizes the fractional composition, volatility of the fuel and its chemical composition. High density means a relatively higher ratio of carbon to hydrogen. Density is more important when purifying fuel by separation. In a centrifugal fuel separator, the heavy phase is water. To obtain a stable interface between fuel and fresh water, the density should not exceed 0.992 g/cm 3 . The higher the density of the fuel, the more complex the control of the separator becomes. Minor changes in fuel viscosity, temperature and density lead to loss of fuel with water or deterioration of fuel purification.

Mechanical impurities in fuel are of organic and inorganic origin. Mechanical impurities of organic origin can cause plungers and nozzle needles to hang in the guides. When the valves or injector needles land on the seat, carbons and carboids stick to the lapped surface, which also leads to disruption of their operation. In addition, carbons and carboids enter diesel cylinders and contribute to the formation of carbon deposits on the walls of the combustion chamber, piston and exhaust tract. Organic impurities have little effect on the wear of parts of fuel equipment.

Mechanical impurities of inorganic origin are abrasive particles by their nature and, therefore, can cause not only freezing of moving parts of precision pairs, but also abrasive destruction of rubbing surfaces, seating ground surfaces of valves, nozzle needle and atomizer, as well as nozzle holes.

Coke residue is the mass fraction of carbonaceous residue formed after combustion of the test fuel or its 10% residue in a standard device. The amount of coke residue characterizes incomplete combustion of fuel and the formation of soot.

The presence of these two elements in fuel is of great importance as a cause of high temperature corrosion on the hottest metal surfaces, such as the surfaces of exhaust valves in diesel engines and superheater tubes in boilers.

When the fuel contains vanadium and sodium simultaneously, sodium vanadates are formed with a melting point of approximately 625 °C. These substances cause a softening of the oxide layer that normally protects the metal surface, causing the destruction of grain boundaries and corrosion damage to most metals. Therefore, the sodium content should be less than 1/3 of the vanadium content.

Residues from the fluidized bed catalytic cracking process may contain highly porous aluminosilicate compounds that can cause severe abrasive damage to fuel system components, as well as pistons, piston rings and cylinder liners.

Oils used

Among the problems to reduce engine wear internal combustion lubrication of the cylinders of low-speed marine engines occupies a special place. During fuel combustion, the temperature of the gases in the cylinder reaches 1600? C and almost a third of the heat is transferred to the cooler walls of the cylinder, the piston head and the cylinder cover. As the piston moves downward, the lubricating film remains unprotected and is exposed to high temperatures.

Oil oxidation products, being in a high-temperature zone, turn into a sticky mass that covers the surfaces of the pistons, piston rings and cylinder liner with a kind of varnish film. Varnish deposits have poor thermal conductivity, so heat transfer from a piston coated with varnish is impaired and the piston overheats.

Cylinder oil must meet the following requirements:

- have the ability to neutralize acids formed as a result of fuel combustion and protect working surfaces from corrosion;

- prevent deposits of carbon deposits on pistons, cylinders and windows;

- have high strength lubricant film at high pressures and temperatures;

- do not produce combustion products harmful to engine parts;

- be stable when stored in ship conditions and insensitive to water

Lubricating oils must meet the following requirements:

- have an optimal of this type viscosity;

- have good lubricity;

- be stable during operation and storage;

- have, if possible, minimal tendency to carbon deposits and varnish formation;

- must not have a corrosive effect on parts;

- must not foam or evaporate.

To lubricate the cylinders of crosshead diesel engines, special cylinder oils for sulfur fuels with detergent and neutralizing additives are produced.

Due to the significant increase in supercharging of diesel engines, the problem of increasing engine service life can only be solved by choosing the optimal lubrication system and the most effective oils and their additives.

Selection of fuel and oils

Indicators	Standards for brands
	Main fuel	Reserve fuel
			L (summer)
Viscosity at 80?C kinematic
Viscosity at 80?C conditional
			absence
			absence

low sulfur
sulfurous
Flash point, ?С
Pour point, ? C
Coking ability, % mass

Density at 15? C, g/mm 3
Viscosity at 50?C, cst
Ash content, % mass
Viscosity at 20? C, cst
Density at 20? C, kg/m3




Elf B.P. Castrol Chevron Exxon Mobile Shell	Atlanta marine D3005 Energol OE-HT30 Marine CDX30 Veritas 800 Marine Exxmar XA Alcano 308 Melina 30/305	Talusia XT70 CLO 50-M

Technical use of marine diesel engines

marine diesel engine gas turbine

Preparing the diesel installation for operation and starting the diesel engine

Preparing a diesel installation for operation must ensure that diesel engines, service mechanisms, devices, systems and pipelines are brought into a state that guarantees their reliable start-up and subsequent operation.

Preparing a diesel engine for operation after disassembly or repair must be carried out under the direct supervision of a mechanic in charge of the diesel engine. In doing so, you need to make sure that:

1. weight disassembled connections are assembled and securely fastened; pay special attention to locking the nuts;

2. the necessary adjustment work has been completed; special attention should be paid to setting the high pressure fuel pumps to zero supply;

3. all standard control and measuring instruments are installed in place, connected to the controlled environment and are not damaged;

4. diesel systems are filled with working media (water, oil, fuel) of appropriate quality;

5. fuel, oil, water and air filters are cleaned and in good working order;

6. When pumping oil with the crankcase shields open, lubricant flows to the bearings and other lubrication points;

7. protective covers, shields and casings are in place and securely fastened;

8. fuel, oil, water and air systems, as well as the working cavities of the diesel engine, heat exchangers and auxiliary mechanisms do not have any leaks of working media; special attention should be paid to the possibility of cooling water leaking through the cylinder liner seals, as well as the possibility of fuel, oil and water getting into the working cylinders or into the purge (suction) receiver of the diesel engine;

9. Diesel injectors were checked for density and quality of fuel atomization.

After completing the above checks, the operations provided for preparing the diesel installation for operation after a short stay must be performed (see paragraphs 1.3--1.9.11).

Preparing the diesel installation for operation after a short stay, during which work related to disassembly was not performed, must be carried out by the mechanic on duty (of the main installation - under the supervision of a senior or second engineer) and include the operations provided for in paragraphs. 1.4.1--1.9.11. It is recommended to combine various preparatory operations in time.

During an emergency start, the preparation time can be reduced only by warming up.

Preparing the oil system

It is necessary to check the oil level in the waste tanks or in the diesel and gearbox crankcases, in the oil collectors of turbochargers, oil servomotors, lubricators, the speed controller, the thrust bearing housing, and in the camshaft lubrication tank. If necessary, replenish them with oil. Drain sludge from lubricators and, if possible, from oil collection tanks. Refill hand grease fittings, wick grease fittings, and cap grease fittings.

You should make sure that automatic replenishment devices and maintenance of oil level in tanks and lubricators are in good working order.

Before cranking the diesel engine, it is necessary to supply oil to the working cylinders, cylinders of purge (supercharging) pumps and to other lubricant lubrication points, as well as to all manual lubrication points.

Oil filters and oil coolers should be prepared for operation, and valves on the pipelines should be installed in the operating position. Starting a diesel engine and its operation with faulty oil filters are prohibited. Remote controlled valves must be tested in operation.

If the oil temperature is below that recommended in the operating instructions, it must be heated. In the absence of special heating devices, the oil is heated by pumping it through the system while warming up the diesel engine (see paragraph 1.5.4); the oil temperature during warming up must not exceed 45°C.

The autonomous oil pumps of the diesel engine, gearbox, and turbochargers should be prepared for operation and started up, or the diesel pump should be pumped with a hand pump. Check the operation of automated (remote) control means for main and backup oil pumps, bleed air from the system. Bring the pressure in the lubrication and piston cooling systems to operating pressure while simultaneously cranking the diesel engine with a turning device. Verify that all system instruments are reading and that there is flow in the sight glasses. Pumping with oil should be carried out during the entire time of preparation of the diesel engine (for manual pumping - before cranking and immediately before starting).

It is necessary to ensure that the alarm lights disappear when the monitored parameters reach operating values.

Preparing the water cooling system

It is necessary to prepare water coolers and heaters for operation, install valves and taps on pipelines in the operating position, and test the operation of remotely controlled valves.

The water level in the expansion tank of the fresh water circuit and in the tanks of the autonomous piston and injector cooling systems must be checked. If necessary, replenish the systems with water.

Autonomous or backup fresh water pumps for cooling cylinders, pistons, and injectors should be prepared for operation and put into operation. Check the operation of automated (remote) controls for the main and backup pumps. Bring the water pressure up to working pressure and bleed air from the system. Pump the diesel engine with fresh water during the entire time of diesel preparation.

It is necessary to warm up the cooling fresh hearth using available means to a temperature of about 45°C at the inlet. The rate of warming up should be as slow as possible. For low-speed diesel engines, the warm-up rate should not exceed 10°C per hour, unless otherwise indicated in the operating instructions.

To check the seawater system, it is necessary to start the main seawater pumps and check the system, including the operation of the water and oil temperature regulators. Stop the pumps and restart them immediately before starting the diesel engine. Avoid prolonged pumping of oil and water coolers with sea water.

You should make sure that the light disappears alarms when the monitored parameters reach operating values.

Preparing the fuel system

You should drain the water from the fuel supply tanks, check the fuel level and, if necessary, replenish the tanks.

Must be prepared to work fuel filters, viscosity regulator, fuel heaters and coolers.

It is necessary to set the valves on the fuel pipeline to the operating position, and test the remotely controlled valves in action. Prepare for operation and start up the autonomous fuel priming and injector cooling pumps. After the pressure rises to operating pressure, make sure there is no air in the system. Check the operation of automated (remote) controls for the main and backup pumps.

If, during parking, work related to dismantling and emptying the fuel system, replacing or disassembling high-pressure fuel pumps, injectors or injector pipes was carried out, it is necessary to remove air from the high-pressure system by bleeding the pumps with the injector deaeration valves open or in another way.

For diesel engines with hydraulic locking nozzles, it is necessary to check the level of the hydraulic mixture in the tank and bring the pressure of the hydraulic mixture in the system to operating level, if this is provided for by the design of the system.

If a diesel engine is structurally adapted to operate on high-viscosity fuel, including starting and maneuvering, and has been stopped for a long time, it is necessary to ensure gradual heating of the fuel system (tanks, pipelines, high-pressure fuel pumps, injectors) by turning on heating devices and continuous circulation of heated fuel. Before test runs of the diesel engine, the fuel temperature must be brought to a value that ensures the viscosity required for high-quality atomization (9-15 cSt), the fuel heating rate must not exceed 2°C per minute, and the fuel circulation time in the system must be at least 1 hour unless otherwise specified in the operating instructions.

When starting a diesel engine on low-viscosity fuel, you should prepare in advance to switch it to high-viscosity fuel by turning on the heating of the consumable and settling tanks. The maximum temperature of fuel in tanks must be no less than 10°C below the flash point of fuel vapor in a closed crucible.

When replenishing consumable tanks, the fuel in front of the separator must be heated to a temperature not exceeding 90°C

Heating fuel to a higher temperature is allowed only if there is a special regulator to accurately maintain the temperature.

Preparation of the starting system, purge, supercharging, exhaust

It is necessary to check the air pressure in the starting cylinders, blow out condensate and oil from the cylinders. Prepare for operation and start up the compressor, make sure it is operating normally. Check the operation of automated (remote) compressor controls. Refill the cylinders with air to the nominal pressure.

The shut-off valves on the way from the cylinders to the diesel shut-off valve should be opened smoothly. It is necessary to purge the starting pipeline with the diesel shut-off valve closed.

It is necessary to drain water, oil, fuel from the purge air receiver, intake and exhaust manifolds, sub-piston cavities, air cavities of gas air coolers and air cavities of supercharged turbochargers.

All diesel gas outlet shut-off devices must be open. Make sure that the diesel exhaust pipe is open.

Shafting preparation

It is necessary to make sure that there are no foreign objects on the shaft line, and also that the shaft line brake is released.

The stern tube bearing should be prepared for operation by ensuring that it is lubricated and cooled with oil or water. For stern tube bearings with an oil lubrication and cooling system, you should check the oil level in the pressure tank (if necessary, fill it to the recommended level), as well as the absence of oil leaks through the sealing seals (cuffs).

It is necessary to check the oil level in the support and thrust bearings, check the serviceability and prepare the bearing lubrication devices for operation. Check and prepare the bearing cooling system for operation.

After starting the gearbox lubrication pump, check the flow of oil to the lubrication points using instruments.

It is necessary to check the operation of the shaft line release couplings by turning the couplings on and off several times from the control panel. Make sure that the on/off alarm and coupling are working correctly. Leave the disconnect couplings in the off position.

In installations with adjustable pitch propellers, it is necessary to put into operation a system for changing the propeller pitch and perform the checks provided for in paragraph 4.8 of Part I of the Rules.

Turning and test runs

When preparing a diesel engine for operation after parking, you must:

turn the diesel engine with a shaft turning device 2-3 shaft revolutions with the indicator valves open;

crank the diesel engine with compressed air into forward or reverse gear;

Carry out test runs using fuel in forward and reverse gear.

When cranking the diesel engine using a turning device or air, the diesel engine and gearbox must be pumped with lubricating oil, and during test runs, also with cooling water.

Cranking and test runs must be carried out in installations that do not have disconnecting couplings between the diesel engine and the propeller - only with the permission of the watch officer;

in installations operating the propeller through a disconnecting clutch - with the clutch disconnected.

Cranking and test runs of the main diesel generators are carried out with the knowledge of the senior or watch electrician or the person responsible for the operation of electrical equipment.

Before connecting the turning device to a diesel engine, you must make sure that:

1. the lever (steering wheel) of the diesel control station is in the “Stop” position;

2. the valves on the starting cylinders and the starting air pipeline are closed;

3. at the control posts there are signs with the inscription: “The turning device is connected”;

4. indicator valves (decompression valves) are open.

When turning a diesel engine with a turning device, you must carefully listen to the diesel engine, gearbox, and fluid couplings. Make sure there is no water, oil or fuel in the cylinders.

While cranking, monitor the load on the turning device's electric motor using the ammeter readings. If the maximum current value is exceeded or if it fluctuates sharply, immediately stop the shaft turning device and eliminate the malfunction of the diesel engine or shaft line. It is strictly forbidden to turn it until the malfunction is eliminated.

Cranking the diesel engine with compressed air must be done with open indicator valves (decompression valves), drain valves of the purge air receiver and exhaust manifold. Make sure that the diesel engine picks up speed normally, the turbocharger rotor rotates freely and evenly, and there are no abnormal noises when listening.

Before trial runs of the installation operating A controllable pitch propeller (CPP), it is necessary to check the operation of the CPS control system. In this case, you should make sure that the propeller pitch indicators at all control stations are consistent and that the blade shifting time corresponds to that specified in the factory instructions. After checking the propeller blade, set the zero pitch position.

Test runs of diesel fuel must be carried out with the indicator and drain valves closed. Make sure that the start and reverse systems are in good working order, that all cylinders are working, that there is no extraneous noise and knocking, oil flow to the turbocharger bearings.

In installations with remote control of the main diesel engines, it is necessary to carry out test runs from all control stations (from the central control room, from the bridge), to ensure the correct operation of the remote control system.

If, due to the ship's mooring conditions, it is impossible to carry out test runs of the main diesel engine using fuel, then such a diesel engine is allowed to operate, but a special entry must be made in the engine log, and the captain must take all necessary precautions in case it is impossible to start or reverse the diesel engine.

After preparing the diesel engine for start-up, the pressure and temperature of water, lubricating and cooling oil, and the starting air pressure in the cylinders should be maintained within the limits recommended in the operating instructions. Shut off the sea water supply to the air coolers.

If the prepared engine is not put into operation for a long time and must be in a state of constant readiness, it is necessary every hour, in agreement with the captain's officer on watch, to turn the engine with a turning device with open indicator valves.

Starting the diesel engine

Operations for starting a diesel engine must be performed in the sequence specified in the operating instructions. In all cases where this is technically possible, the diesel engine should be started without load.

When putting the main diesel engines into operation in 5 - 20 minutes. before moving (depending on the type of installation) from the navigation bridge to the engine room must be a corresponding warning has been sent. During this time, the final operations to prepare the installation for operation must be completed: the diesel engines running on the propeller through disconnecting devices must be started, the necessary switchings in the systems must be made. The engineer on watch reports to the bridge that the installation is ready for operation in the usual manner on board the ship.

After starting, prolonged operation of the diesel engine should be avoided. Idling and the lightest load, as this leads to increased deposits of contaminants in the cylinders and flow parts of the diesel engine.

After starting the diesel engine, it is necessary to check the readings of all control and measuring instruments, paying special attention to the pressure of lubricating oil, coolants, fuel and hydraulic mixture in the injector hydraulic locking system. Make sure there are no abnormal noises, knocks or vibrations. Check the operation of the cylinder lubricators.

If there is an automated starting system for diesel generators, it is necessary to periodically monitor the condition of the diesel engine in the “hot reserve”. In the event of an unexpected automatic start of a diesel engine, the reason for the start should be established and the values of the monitored parameters should be checked using available means.

It is necessary to ensure constant readiness to start diesel drives of emergency units and rescue equipment. Checking the readiness of emergency diesel generators must be carried out in accordance with paragraphs. 13.4.4 and 13.14.1 of Part V of the Rules.

Checking the operability and readiness to start the engines of life-saving equipment, emergency fire pumps and other emergency units must be carried out by a supervising mechanic at least once a month.

Typical malfunctions and malfunctions in the operation of diesel installations. Their prAndcauses and solutions

Malfunctions and problems during start-up and maneuvers

When starting a diesel engine with compressed air crankshaft doesn't touch meWitheither, when starting off, it does not make a full revolution.

Cause	Measures taken
1. Shut-off valves of launch cylinders or pipeline are closed	Open shut-off valves
2. Starting air pressure is not enough	Refill air cylinders
3. There is no air (oil) supplied to the launch control system or its pressure is insufficient	Open the valves or adjust the air and oil pressure
4. The crankshaft is not set to the starting position (in diesel engines with a small number of cylinders)	Set the crankshaft to the starting position
5. Elements of the diesel starting system are faulty (the main starting valve or the air distributor valve is stuck, the pipes from the air distributor to the starting valves are damaged, clogged, etc.)	Repair or replace system elements
6. The starting system is not adjusted (the air distributor valves do not open in a timely manner, the pipes from the air distributor are incorrectly connected to the starting valves)	Adjust the starting system
7. Elements of the DAU system are faulty	Fix the problem
8. Gas distribution is disrupted (angles of opening and closing of starting, intake and exhaust valves)	Adjust gas distribution
9. Turning device air lock valve is closed	Turn off the turning device or repair the faulty blocking valve
10. Shaft brake is clamped	Release the brake
11. The propeller hits an obstacle or the propeller	Release the propeller
12. Freezing of water in the stern tube	Warm up the stern tube

The diesel engine develops a rotation speed sufficient for starting, but when switched to fuel, flashes in the cylinders do not occur, or occur with misfires, or the diesel engine stops.

Cause	Measures taken
1. Fuel does not flow to the fuel pumps or arrives, but in insufficient quantities	Open the shut-off valves on the fuel line, eliminate the malfunction of the fuel priming pump, clean the filters
2. Air has entered the fuel system	Eliminate leaks in the system, bleed the system and injectors with fuel
3. A lot of water got into the fuel	Switch the fuel system to another supply tank. Drain the water from the system and bleed the injectors.
4. Individual fuel pumps are turned off or faulty	Turn on or replace fuel pumps.
5. Fuel enters the cylinders with a large delay	Set the required fuel supply advance angle
6. Fuel pumps are turned off by the speed limiter	Place the regulator in working position
7. Sticking in the regulator or shut-off mechanism	Eliminate jamming
8. Excessively high fuel viscosity	Fix the malfunction in the fuel heating system and switch to diesel fuel.
9. End pressure of compression and working cylinders is insufficient	Eliminate valve leaks. Check and adjust gas distribution. Check the condition of the sealing rings.
10. Diesel is not warmed up enough	Warm up the diesel
11. Control valves for pumping injectors are open or leaking	Close control valves or replace injectors
12. Turbocharger filters are closed	Open filters

During start-up, the safety valves are blown (“shoot”)

The diesel engine does not stop when the control lever is moved to the “Stop” position.

Cause	Measures taken
1.Zero flow of fuel pumps is installed incorrectly	Install the control levers in “Start” position to reverse (brake with air). After stopping the diesel engine, set the lever to the “Stop” position On a non-reversible diesel engine, close the air intake device using available means, or manually turn off the fuel pumps, or close the access of fuel to the pumps. After stopping the diesel engine, adjust the zero flow of the pumps
1.1 Jamming (seizing) of fuel pump racks	Eliminate jamming (jamming)

Diesel rotation speed is higher or lower than normal (wAgiven)

Diesel does not develop speed full speed with the fuel controls in the normal position.

Cause	Measures taken
1. Increased resistance to vessel movement due to fouling, head wind, shallow water, etc.	Be guided by paragraphs. 2.3.2 and 2.3.3 of Part II of the Rules
2.Fuel filter is dirty	Switch fuel system to a clean filter
3.Fuel is poorly atomized due to faulty injectors, fuel pumps or high viscosity fuel	Faulty injectors and fuel replace pumps. Increase fuel temperature
4. The fuel supplied to the diesel pumps is overheated	Reduce fuel temperature
5.Low purge air pressure
6. Insufficient fuel pressure in front of diesel fuel pumps	Increase fuel pressure
7. The speed controller is faulty

The diesel engine speed drops.

Cause	Measures taken
1. In one of the cylinders, the piston began to seize (jam) (a knock is heard with each change in the piston stroke)	Immediately turn off the fuel and increase oil supply n and emergency cylinder, reduce the diesel load. Then stop the diesel and inspect the cylinder
2. Fuel contains water	Switch fuel system to receive from another supply tank, drain water from the supply tank tanks and systems
3. One or more fuel pumps have stuck plungers or stuck suction valves	Eliminate jamming or replace plunger pair, valve
4. The needle is stuck on one of the injectors (for diesel engines, Not having non-return valves on injectors and discharge valves on fuel pumps)	Replace the injector. Delete WHO spirit from the fuel system

The diesel suddenly stops.

Cause	Measures taken
1. Water has entered the fuel system
2. Speed controller is faulty	Fix the regulator malfunction
3. The diesel emergency protection system has tripped due to controlled parameters falling outside the permissible limits or due to a system malfunction	Check the values of the monitored parameters. Eliminate neis correctness of the system
4. The quick-closing valve on the supply tank has closed	Open quick-closing valve
5. No fuel in the supply tank	Switch to another supply tank. Remove air from the system
6, Fuel line is clogged	Clean the pipeline.

The rotation speed increases sharply, the diesel engine starts to “peddle”.

Immediate action. Reduce the rotation speed or stop the diesel engine using the control lever. If the diesel engine does not stop, close the diesel air intakes using available means and stop the fuel supply to the diesel engine.

Cause	Measures taken
1. Abrupt load shedding from the diesel engine (loss of the propeller, disconnection of the coupling, sudden load shedding from the diesel generator, etc.) with simultaneous malfunction of the regulator ditch rotation speed (all-mode and limit) or their drives	Inspect, repair and from adjust the regulator and the drive from it to the shut-off mechanism of the fuel pumps. Eliminate the cause of load shedding
2. Incorrectly set zero fuel supply, presence of fuel or oil in the purge receiver, large drift of oil from the crankcase into the combustion chamber of the trunk diesel engine (the diesel engine accelerates after starting at idle or removing the load)	Immediately load the diesel engine or stop the air supply to the air intake devices. After stopping, adjust the zero flow, inspect the diesel engine

Bibliography

1. Vanscheidt V.A., Design and strength calculations of marine diesel engines, L. "Shipbuilding" 1966

2. Samsonov V.I., Marine internal combustion engines, M "Transport" 1981

3. Handbook of ship mechanics. Volume 2. Generally edited by L.L. Gritsaya.

4. Fomin Yu.Ya., Marine internal combustion engines, L.: Shipbuilding, 1989

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Ministry of Education and Science, Youth and Sports of Ukraine

"Odessa National Maritime Academy"

Course work

Discipline: Marine internal combustion engines

Completed

Pisarenko A.V.

Checked:

prof. Gorbatyuk V.S.

Odessa 2012

Introduction

Many years of practice have shown that on all types of ships of the merchant and specialized fleet, the advantage of using an internal combustion engine as the main engine is obtained.

High efficiency in terms of specific fuel consumption, high efficiency, significant service life and reliable engine operation are the main reasons for the use of diesel engines in the marine fleet.

Along with the frequently used complex, which consists of a piston engine, gas turbines and compressors, on transport ships with powerful diesel units. Most of the time, working in a constant full load mode, at transitions between ports, a combined type scheme with heat recovery from exhaust gases in gas turbine engines is widely used. and in a recovery boiler, which significantly increases engine efficiency. If there is sufficient steam from the recovery boiler, a turbogenerator is additionally installed, which provides the vessel with electricity while underway, which allows saving fuel for the operation of the diesel generator.

Such diesel installations are equipped with remote control means, systems and devices for constant monitoring of operating parameters of the temperatures of critical engine components, coolant and oil, and alarm and warning protection systems with recording of all parameter outages from permissible limits on a control tape.

At present and in the near future, the main direction of development of the marine diesel structure involves improving the operating process of the engine aimed at increasing efficiency in fuel and oil consumption, deep utilization of the heat of exhaust gases and cooling water, increasing the reliability of diesel engines in all operating modes, improving design and application , better quality materials.

Leading diesel construction companies will be widely used on transport and specialized fleet vessels, including: Burmeister and Wein (Denmark), MAN (F.R.G.), Sulzer (Switzerland), Buryansk Motor-Building Plant " (Russia).

To complete the course project, use a Burmeister and Wein engine of the 5DKRN 62/140 brand as a prototype engine.

1. Engine design data

The engine is two-stroke, with direct-flow valve scavenging, crosshead, reversible, supercharged, right-hand rotation, with a number of 8 cylinders and an aggregate power of 10,000 hp. With.

The purge system when the engine is running in reverse, the exhaust valve opens at 83 BC. and closes at 63 after b.m.t. Gas turbine engine pressurization.

Purge system when operating at forward movement has the following gas distributions. The exhaust valve opens at 89 BC. closing at 57 after b.m.t. Exhaust valve opening angle at 146 purge ports at 76 turns crankshaft.

Air is supplied to the cylinder by a centrifugal supercharger through a finned tubular air cooler, a common welded receiver and under the piston cavities.

The engine fuel supply system is designed as follows. The fuel priming pump is a piston, two-cylinder, with a discharge pressure of 3-4 MPa. It is driven by a crank at the nose end of the crankshaft. Filters fine cleaning- with cartridges made of thin felt.

The high pressure pump is of the spool type, with adjustment at the end of the flow. The maximum injection pressure is 600 kPSm. The plunger has a diameter of 28 mm and a stroke of 42 mm. The cam washer is of a symmetrical profile, consisting of two halves.

Nozzle closed type cooled by fuel. Opening pressure force 220 kPcm. The flat-tipped needle has a lift of 0.7 mm, the nozzle has three holes with a diameter of 0.67 mm.

At the forward end of the frame there is a diesel fuel cooler, and with a heavy fuel system, a fuel heater with a thermostat.

The cylinder cooling system and exhaust valve are closed, dual-circuit, with pumps driven by electric motors.

Fresh water is supplied to the cylinders under pressure!.8 atm. from the main line and, having passed the covers and housings of the exhaust valves, is discharged at a temperature of 6065 ° C through the pipes into the main line. Sea water for cooling the air coolers is supplied at a pressure of 0.8 atm. and is discharged at a temperature of 40-45 °C through pipelines.

The circulating lubrication system is serviced by pumps driven by an electric motor. Oil for the crank mechanism, thrust mechanism drive compartment, drive compartment, thrust bearing and exhaust valve drive is supplied under a pressure of 1.8 atm. along the highway.

The cylinder liner, made of alloy cast iron, has 18 purge windows with a height of 9.8 mm with a total of 1008 mm. In the horizontal plane, the windows have a tangential direction. The bushing is sealed along the jacket at the top by lapping the supporting surfaces, at the bottom - with one red copper belt. Lubricant is supplied to the bushing mirror above the purge windows through two fittings with ball non-return valves. The cylinder cover made of heat-resistant alloy steel is sealed at the end of the sleeve by lapping; the cover contains an exhaust valve with an average diameter of 250 mm with a stroke of 66 mm, two nozzles, a safety valve and an indicator valve. From the cylinder to the cover, cooling water passes to two pipes and through two pipes from the cover to the exhaust valve body of the piston - a composite engine. The alloy steel head houses three upper O-rings, 10mm high and 17mm wide. The short guide is made of alloy cast iron.

A welded displacer and radial holes in the cylindrical part of the piston bottom contribute to better heat transfer from the walls to the oil. Oil is supplied through a tube. A rod with a diameter of 170 mm made of carbon steel is attached to the piston head through a guide with a flange using studs. The rod is connected to the crosshead crossbar by the end annular surface through a guide cylindrical shank with a gull. At the bottom of the rod, oil is supplied to a tube, sealed with a bushing that separates the supply cavity from the drain cavity. The multi-piece cast iron rod seal has two oil scraper rings and two O-rings.

The engine crosshead is double-sided, with 4 cast steel sliders, which are pinned to the highlanders of a forged steel cross member. The working surfaces of the sliders are filled with babbitt. Connecting rod with detachable head and ball bearings, made of cast steel and filled with babbitt. Head bearings with a diameter of 280 mm and a width of 170 mm each have two connecting rod bolts and a crank with a diameter of 400 mm with a width of the upper half of 240 mm and a width of the lower bearing head of 170 mm have two full connecting rod bolts. The bolts are made of alloy steel and do not have centering belts. The connecting rod rod with a diameter of 190 mm with a rigid, non-fork head is hollow, made of alloy steel. The connecting rod rod and bearings have holes for supplying oil from the crank bearing to the head bearings.

The crankshaft is composite: frame and crank journals made of carbon steel have a diameter of 400 mm and a length of 254 mm; cast steel rails with a width of 660 mm and a thickness of 185 mm; The hollow necks are closed at the ends of the lid and with screws. Due to lubrication and strength conditions, the radial holes in the crank journals are shifted from the plane of the crankshaft.

Due to the engine balancing conditions, some cheeks are cast with counterweights. The thrust bearing of the engine is single-comb, with six swinging forward and reverse thrust segments, which are located in two sectors, and secured in a welded housing with two covers. The turning device includes an electric motor connected to the wheel on a thrust shaft through two worm gears.

From the pan at a temperature of 45-52 ° C, the oil is discharged into the waste tank.

The working cylinder bushings are lubricated by lubricators with a camshaft drive. The bearings of gas turbochargers receive lubrication from an independent system with a gear pump driven by an electric motor.

The drive of the camshaft of the fuel pumps and the camshaft of the exhaust valves is made by a single rack chain with a pitch of 89 mm. An indicator drive for each cylinder, consisting of a lever and a crown rod, receives movement from the eccentric along the exhaust camshaft. The cam roller of the spool air distributor in block design has chain drive from the camshaft, fuel pumps.

The engine control post has a starter and fuel handle. The engine is started using compressed air at a pressure of 30 kg/cm with simultaneous fuel supply. The direction of rotation of the engine shaft is changed after reversing the air distributor automatically to the starting state by turning the crankshaft relative to the locked camshafts of the fuel pumps and exhaust valves.

The following are installed at the control station: a mechanical tachometer, a rotation direction indicator, a total engine speed counter, pressure gauges for oil, fuel, purge air, fresh and sea water, oil and exhaust gases. At the control station there are also remote tachometers for each gas turbocharger and a flywheel for shut-off starting air.

The foundation frame, bed with A-shaped blades, stand consisting of two sections, and the frame of the drive compartment are of welded construction.

The frame and the stand are connected with short bolts. Double-sided cast iron parallels are fixed to the racks. The crankcase compartments are covered by removable steel shields with inspection windows and spring-loaded safety plates. The cylinder block consists of separate large jackets. To increase the speed of water in the cooling cavity, the flow area has been reduced - especially in the area of the upper part of the sleeve. The jackets have hatches for inspection of the cooling cavities. Short alloy steel anchor ties connect the cylinder jackets via a stand to the top reinforced crankcase riser plate. The connections are placed in the connector cavities of the shirts.

2. Thermal calculation

The main task of the verification calculation is to estimate the parameters of the operating cycle in the operating mode of the engine. In this case, the values of parameters controlled in operation using standard instruments are used.

2.1 Filling process

Air pressure at the compressor inlet.

P0? = P0-Drf kgf/cm (1)

Where, P0 is barometric pressure, 720 mmHg (set)

Drf-pressure drop across air filters GTK, 93 mm water column (specified)

1mmHg=0.00136 kgf/cm

1 mm water column = 0.0001 kgf/cm

P0?=720*0.000136-95* 0.0001=0.96

Air pressure after compressor

рк=рs + Дрх kgf/cm (2)

where, ps - air pressure in the receiver (after the refrigerator), 1.42 kgf/cm

Дрх - pressure drop across air coolers 250 mm.water column (set)

pk=1.6+140*0.0001=1.614

Compressor pressure ratio

p k= pk/ P0? (3)

r k=1.614/0.96=1.68

Pressure in the cylinder at the end of filling

For two-stroke engines with direct-flow valve purge and with loop-loop engines from Sulzer.

pa=(0.96-1.05) рs (4)

For calculation we take 1.01

Ra=1.01*1.6=1.616

Charge air temperature in the receiver (after the refrigerator)

Tk=T? с *рк ^(nk-1/nk) K (5)

where is T? с= Т0= 273 +t0- air temperature at the compressor inlet

nk is an indicator of the compression polytrope in the compressor. For centrifugal pumps with a cooled casing nk=1.6-1.8. For calculation we take nk=1.7

T? с=273+35=308

Tk =308*1.616^(1.7-1/1.7)=375.76

Air temperature in the receiver

Тs=273+ tз.в. +(15-20) K (6)

where tз.в - temperature of sea water (tз.в = 17С)

Тs=273+10+17=300

Air temperature in the working cylinder taking into account heating (Dt) from the walls of the combustion chamber.

Т?s= Тs + Дt К (7)

Where Dt=5-10C for calculation we take Dt=7C

Temperature of the mixture of air and residual gases at the end of filling

Ta= (T?s+ r Tr) /1+r K (8)

where r is the coefficient of residual gases. For two-stroke engines with direct-flow valve purge r = 0.04-0.08.

For calculation we take r=0.06

Tr-temperature of residual gases Tr=600-900. For calculation we take Tr=750

Ta=(307+0.06 *750) /1+0.06=332

Filling coefficient related to the useful piston stroke

z n= (/ -1)* (pG/ps)* (Ts/Ta)*(1/1+r) (9)

where is the compression ratio value. For low-speed engines = 10-13. For calculation we take =12

z n=(12/12-1)*(1.616/1.6)*(301/332)*(1/1+0.06)=0.94

The filling coefficient is related to the full stroke of the piston.

h? n= z n(1- s) (10)

where s is the relative lost stroke of the piston. For engines with direct-flow valve purge s=0.08-0.12. For calculation we take s=0.1

h? n=0.94(1-0.1)=0.85

Full cylinder displacement.

V?s= рD^2/4*S m

V?s=0.785*0.62^2*1.4=0.24

Charge air density

s=10^4*Ps/R*Ts kg/m

where R=29.3 kgm/kg deg (287 J/kg rad) is the gas constant

s=10^4*1.6/29.3*301=1.8

Air charge related to the full working volume of the cylinder.

(kg/cycle) (11)

where d is the air moisture content, determined depending on temperature and relative humidity (Table 1)

2.2 Compression process

For low- and medium-speed engines n1 =1.34+1.38. For calculation we take 1.36

First approximation n1 =1.36

Second approximation n1 =1.377

We accept n1 =1.375

Pressure at the end of the compression process.

Рс = ра * kgf/cm (13)

Pc= 1.616-12" 377 =49.48

Temperature at the end of the compression process.

Tc = Ta* K (14)

Tc = 333 -12 0 - 377 =849.7

For reliable self-ignition of fuel, Tc must be at least 480 + 580 "C or 753 +853 "K.

2.3 Combustion process

Maximum combustion pressure.

p: = rs *l kgf/cm (15)

where, l=Pz/Pс - degree of pressure increase. For low-speed engines l = 1.2 /1.35. For calculation we take l = 1.3

p z = 49.48 *1.3 = 64.32

The maximum combustion temperature is determined from the combustion equation, which can be reduced to the form.

ATz 2 +BTz -C=o

Solving the quadratic equation, we get:

where, хz is the coefficient of heat utilization at the start of expansion; For low-speed engines zhz = 0.80 0.86.

For calculation we take z=0.83

Net calorific value

Qн = 81С + 300Н -26(0-S)- 6(9 Н + W) kcal/kg, (17)

where, C, H, 0,W, is the content of carbon, hydrogen, sulfur and water% For the calculation, we are given F-12 naval fuel oil. From Table 2 we take C = 86.5%, H = 12.2%, S = 0.8%, O = 0.5%, Qn = 9885 kcal/kg.

The amount of air theoretically required for complete combustion 1kg of fuel:

in volumetric units

Lo= kmol/kg (18)

in units of mass

Go=Lo *mo kg/kg (19)

where mo =28.97 kg/kmol - mass of 1 kmol of air

G0 = 0.485 * 28.97 = 14

The amount of air actually supplied to the cylinder for complete combustion of 1 kg of fuel:

in volumetric units

L=d*L0 kmol/kg (20)

in units of mass

G =d* G0 kg/kg (21)

Where d- coefficient of excess air during fuel combustion. For low speed engines d= 1.8 + 2.2. For calculation we accept d=2.

L = 2*0.485 = 0.97

Theoretical coefficient of molecular change. (22)

Actual coefficient of molecular change.

The average molar isochoric heat capacity of the mixture of fresh air charge and residual gases at the end of the compression process.

(mS v) s cm = (mCv) s air = 4.6 + 0.0006 * Tc kcal/kmol deg (24)

(mS v) s cm =4.6 + 0.0006-849.7 = 5.11

The average molar isobaric heat capacity of the mixture of “clean” combustion products with excess air and residual gases remaining in the cylinder after combustion.

Let's substitute the obtained values into equation (25).

2.4 Expansion process

Degree of pre-expansion.

The degree of subsequent expansion.

The average exponent of the expansion polytrope z2 is determined by the method of successive approximation from the equation:

Since we do not need greater accuracy when calculating z2 using formula (28), the value of z2 for low-speed engines is z2 = 1.27/ 1.29, choose z2 = 1.28

Pressure at the end of expansion. (29)

рb = 64.32*1/6.59 1 "28 = 5.75

Temperature at the end of expansion. (thirty)

2.5 Gas parameters in the exhaust tract

Average gas pressure behind the cylinder exhaust organs.

рr- = рs-жn kgf/cm (31)

where Жn=(0.88/0.96) is the coefficient of pressure loss during purging in the intake and exhaust parts. For calculation, we take zn = 0.92.

Pr=1.6*0.92 = 1.47

Average gas pressure in front of turbines

PT=Pr*fr kgf/cm (32)

where, zg = 0.97 + 0.99) is the coefficient of pressure loss during purging in the exhaust from the cylinder to the turbines. For calculation we take zh = 0.98.

PT = 1.47 *0.98 = 1.44

Average temperature of gases in front of turbines. (33)

where, qg = (0.40 + 0.45) - relative heat loss with exhaust gases in front of the turbines. For calculation we take qr=0.43. c a - blowing coefficient. For two-stroke engines with gas turbine engines, ca = 1.6 / 1.65. For calculation we take tsa = 1.63.

C R g = (0.25 / 0.26) - average isobaric heat capacity of gases. For calculation we take Cpr=0.26.

2.6 Energy and economic indicators of the engine

The average indicator pressure of the theoretical cycle, related to the useful stroke of the piston, according to the Mazing-Sinetsky formula.

Pn=kgf/ (34)

The average indicated pressure of the theoretical cycle, related to the full stroke of the piston.

Average indicator pressure of the assumed actual cycle.

Where, is the diagram rounding factor. For two-stroke engines with direct-flow valve purge. For calculation we accept

P=12.14*0.97=11.77

Indicated engine power in operating mode.

Where, z is the cycle coefficient. For two-stroke engines z=1

Rated indicated engine power.

Where is the mechanical efficiency of the engine at nominal mode. For two-stroke

For calculation we accept

Mechanical efficiency of the motor in operating mode.

Average effective pressure in operating mode.

Pc = 11.77-0.92 =10.82

Effective engine power in operating mode.

Nc=Ni*зm hp (41)

Nс=7439 -0.92* 6843.88

Specific indicator fuel consumption in operating mode.

kg/hp.h. (42)

Specific effective fuel consumption in operating mode.

kg/hp.h. (43)

Hourly fuel consumption in operating mode.

Cyclic fuel supply in operating mode.

Indicated efficiency in operating mode.

Effective efficiency in operating mode.

z = 0.49-0.92 = 0.45

2.7 Byindicator chart structure

We take the volume of the cylinder Va on a scale equal to the segment A = 120 mm.

We plot the found volumes on the x-axis. Let's determine the ordinate scale:

mm/kgf/cm

B - the length of the segment is 1.3-1.6 times less than segment A. We take B to be 1.5 times. H=80mm.

We determine the intermediate volumes and the corresponding compression and expansion pressures. The calculation is made in tabular form.

Using the table data, we plot characteristic points on the diagram and construct polytropes of compression and expansion. The diagram constructed is theoretical (calculated).

To construct the proposed indicator diagram, we round the corners of the theoretical diagram at points C. Z and Z. The actual release process begins at point b, the position of which on the diagram will be found using the F.A. diagram. Brix.

Crank radius on the scale of the Drawing.

Brix amendment.

where l is the simplest crank mechanism. We take l = 0.25. The angle (ts of the beginning of the opening of the exhaust valve is assumed to be 90 P.K.E. to B.M.T.

From point O, using a protractor, we plot the angle (tb) from the abscissa axis, draw a vertical line until it intersects with the expansion curve and find the position of point b. > We connect points b and a with a curve.

Table 1

3. Dynamic calculation engine

3. 1 Problems of kinematic and dynamic analysis of crooked motionpin and connecting rod mechanism (KShM)

During operation, parts of an internal combustion engine are exposed to various forces. The most critical component of the internal combustion engine is the crankshaft.

The following forces act in the engine crankshaft during its operation:

1) Gas pressure on the piston:

where: r g - gas pressure in the engine cylinder, MPa;

F - piston crown area With () ;

2) Inertia of progressively moving masses

where: m pd - mass of progressively moving parts, kg;

a - piston acceleration m/ ;

3) Gravity forces of progressively moving masses:

4) Friction forces.

They cannot be precisely determined theoretically and are included in the mechanical losses of the engine. The forces of weight (gravity) are small compared to other forces and therefore are usually not taken into account in approximate calculations.

Total moving force:

Since we do not yet know the mass of the parts of the designed internal combustion engine, for the calculation we use specific forces per unit piston per cm 2 (m 1). Thus:

3. 2 Determination of driving force

Construction method

The indicator diagram, constructed on the basis of the calculation of the working process, gives the dependence of p g on the piston stroke. For further calculations, it is necessary to relate the forces acting on the internal combustion engine to the angle of rotation of the crankshaft.

A straight line AB is drawn parallel to the abscissa axis of the indicator diagram constructed based on the results of calculating the parameters of the internal combustion engine cycle. The segment AB is divided in half by the point O and a semicircle is described from this point with radius OA. From the center of the circle (point O) towards BDC, a segment 00 1 = 0.5g is laid off - Brix correction, where g = OA (to maintain scale).

Constant crankshaft;

where: R - crank radius;

L is the length of the connecting rod between the bearing axes.

The value of I is taken within the following limits:

For low-speed crosshead engines 1/4.2 - 1/3.5;

In our case we take X = 0.25.

From O1 (Brix pole), a second circle (larger than the first) is described with an arbitrary radius and divided into equal parts (usually after 5-15°). Rays are directed from the Brix pole through the division points of the second circle.

To construct the diagram we take -p.k.v.

For the expanded indicator diagram P g = (a), we take the scale along the ordinate axis M ord = 10 mm. I MPa and along the abscissa axis M abc = 20 degrees, 1 cm.

Because the accepted scale along the ordinate axis is 1.5 times less than the scale of the p - V diagram, therefore the ordinates taken from it are divided by 1.5 and set aside for the corresponding and in the diagram P g = (a).

To construct a diagram of inertia forces P g = ѓ (a), we take t pd = 7000

The diagram of moving forces is constructed by summing the ordinates of the diagrams Р, =/(а) and Р ы =/(а) taking into account their signs.

3. 3 Construction of a tangential force diagram

1. Method for constructing a diagram for one cylinder:

We construct a diagram of tangential forces on the same scale as the diagram of moving forces: M abc = 20 degrees / cm, M ord = 10 mm / MPa.

Compiling table 3. Trigonometric function : determine for = 1/4 from Table 2; R d - based on Fig. 3 in mm.

The tangential force (tangential) is determined by the formula:

Ra is the driving force (see above).

Trigonometric function, which is determined from Table 3 depending on a p.k.v. And:

The angle of deviation of the connecting rod axis from the cylinder axis.

The determined values - , P 0 , P K are summarized in tables 3 and 4, on the basis of which a diagram of tangential forces for one cylinder is constructed (Fig. 3).

Table 3


Working stroke (expansion)

Table 4. Calculation of inertia forces of translationally moving masses P and =ѓ(a) MPa

	Engine 5 DKRN 62/140

2. Method for constructing a summary diagram of tangential forces.

The total diagram of tangential forces is plotted on the same scale as the diagram of tangential forces of one cylinder (Fig. 36)

Determine the specific resistance force

And average tangential force

Y-axis scale = 10 mm/MPa, therefore

Diagram construction error

What is acceptable

3. 4 Flywheel calculation

marine engine connecting rod flywheel

To calculate the flywheel, the values of crankshaft rotation unevenness are initially specified:

Determining the scale of the summary chart area

Regarding

We plan the area of excess work:

We determine the specific excess work:

Then the redundant work:

where: R - crank radius (m); moment of inertia of the moving parts of the engine and flywheel:

Moment of moving parts of internal combustion engine:

We calculate the moment of inertia of the flywheel:

4=1483.08(kg/)

We accept the given flywheel diameter :

where: S - overall dimensions; prototype engine, m; Then:

Calculate the mass of the rim:

We define total weight flywheel:

0.88 -= 0.8 - 7 3 5.21 = 572.2 (kg)

We determine the dimensions of the flywheel rim from the expression:

Where: R- density. For steel p = 7800(kg/m) . b and h are the width and thickness of the rim, respectively, m. We take the thickness of the rim equal to h = 0.2 m, then:

Maximum flywheel diameter:

2.88 + 0.04 = 2.92 (m)

Checking the peripheral speed of the flywheel rim:

The resulting value is acceptable for the designed engine.

Listliterature

1. Pointing method

2. Mikheev V.G. "Main ship power plants." Methodological recommendations for course design for the maritime and Arctic schools of the Minimarfleet. M., TsRIL "Morflot", 1981, 104 p.

3. Gogin A.F. " Marine diesels", fundamentals of theory, design and operation. Textbook for river schools and technical schools of water transport: 4th ed. Reworked And supplemented - M., Transport, 1988. 439 p.

4. Lebedev O.N. "Ship power plants and their operation." Textbook for universities in aquatics. transport - M.: Transport, 1987 - 336 p.

5. A.A. Foka, Mitryushkin Yu.D. "Maintenance of a vessel during a voyage"

6. A.N. Neelov “Rules for technical operation of ships technical means", Moscow 1984. - 388 p.

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...

Sulzer Company

Uses one set of cam washers to reverse 2-stroke internal combustion engines. Reverse is carried out before starting the engine by turning the camshaft to the required angle relative to the crankshaft using a special servomotor.

In Burmeister and Wein engines, the air distributor roller has 2 sets of cams and, when reversed, moves in the axial direction. The fuel and gas distribution shaft in low-speed engines of the old design had one set of washers and was reversed after the engine began to rotate in the opposite direction (the crankshaft seemed to turn relative to the camshaft).

In engines of the 4th modification, Burmeister and Wein switched to camshaft reverse on the same principle as Sulzer. In the most common modern engines a number of MS MAN- B&W camshaft does not reverse at all; Together with the reverse of the air distributor, only the fuel supply moments change by moving the injection pump pusher earring with the help of a servomotor individually to each cylinder.

The success of reversing and starting the engine in reverse depends on the operating mode from which reverse is required. If, when maneuvering, the ship's speed is close to 0, the engine is running at low speed or even stopped, then reversing does not cause difficulties. Reversing from medium or full speed is a particularly complex and responsible operation, since it is usually associated with an emergency situation. The complexity increases to a greater extent, the greater the displacement and speed of the vessel.

If it is necessary to reverse from full speed (point 1 in Fig. 3), the fuel supply to the cylinders is turned off. In this case, the driving torque becomes equal to 0, the rotation speed quite quickly - in 3-7 seconds - drops to n = (0.5-0.7)n n. The equation of motion during this period has the form:

I (d ω / d τ) = M B + M T (No. 2)

Where ℑ (dω/dτ)- moment due to inertia forces;
M V- moment developed by the screw;
M T- moment due to friction forces.

The propeller rotates due to the inertia forces of the shaft line and the engine and creates some positive thrust. At a certain rotation speed, the torque and thrust of the screw become zero, although the screw continues to rotate in the same direction (point 2 in Fig. 3). With a further decrease in the rotation speed, the thrust becomes negative, the propeller begins to work like a hydraulic turbine due to the inertia of the ship's hull. The equation of motion during this period has the form:

I (d ω / d τ) + M B - M T (No. 3)

A further reduction in rotation speed is achieved due to the torque from friction forces M T and reducing the speed of the ship's hull (reducing the moment M V). The engine will stop when right part the above dependence will become equal to its left side (point 3 in Fig. 3). In this case, the speed of the vessel is usually reduced to 4.5-5.5 knots. To reach this point, a long time is required (from 2 to 10 minutes), which is sometimes absent. Therefore, it is necessary to resort to stopping the shafting with the help of “counter air” supplied to the cylinder through the starting valves.

Rice. 3 Curves of propeller action during counter-air braking from full (ph) and medium (cx) stroke

Reverse order for counter-air

After turning off the fuel supply, the reverse lever is moved from the “forward” position to the “backward” position, although the crankshaft continues to rotate forward, the camshaft is reversed;
In the area of point 2 (Fig. 3), starting air begins to be supplied to the cylinder, while the engine is braked, because air supply is supplied to the compression line;
After stopping, the engine spins up in the air in the “backward” direction and is switched to fuel.

If, during normal startup, air was supplied to the cylinder along the expansion line from the corners φ B1 = 0 to φ B2 = 90° pkv after TDC, then when counter-air is supplied, the geometric moments of the air supply change to the opposite. Air begins to enter the cylinder at the compression line 90° p.c. before TDC and ends at TDC. In this case, the actual moments of air supply and the effectiveness of counter-air braking depend on the design of the cylinder starting valves.

If the trigger valve poppet has the same diameter as the control piston, the valve will close when cylinder pressure is reached R C approximately equal to pressure R V in the starting line (Fig. 4).

Rice. 4 Equilibrium characteristics of starting valves

a) p r and D y = D k l;

b) p r and D y = 1.73 D k l

This occurs well before the geometric end of the air supply to the cylinder. In this case, the air remaining in the cylinder will be compressed and continue to slow down the engine. In the TDC area, part of the air is released into the atmosphere through a safety valve. The amount of air released is small, given the small cross-section safety valve. At further movement piston when it passes TDC, compressed air expands and continues to spin the diesel engine. Thus, if the engine stops before the piston reaches TDC, then counter-air braking will be effective; if it does not stop, counter-air is ineffective. This pattern of counter-air braking is observed in low-speed MAN engines.

If the area of the control piston is larger than the valve plate (Burmeister and Wein, Sulzer engines), then much more pressure in the cylinder is required to close the valve (Fig. 4). The valves open when braking with counter-air during the compression stroke, and after reaching pressure R C - P V air from the cylinder begins to flow at high pressure into the starting line. The piston performs pushing work on the compression line.

The start valve closes in accordance with the geometric moment of the air supply. With such a valve, the compression work is much greater more work expansion, the counter-air braking effect is good. The air pushed out of the cylinder into the starting line enters the adjacent cylinder, which reduces starting air consumption. With this type of starting valves, the ship's run-out is reduced due to the faster start of the diesel engine in reverse.

When reversing from full speed, the engine is usually exposed to air to ensure starting in the opposite direction. There is no need to do this - you only need to set the fuel rail to a higher flow when switching to fuel.

Bringing great ideas to life is a matter of time. But these great ideas themselves always come suddenly. Either at night or when drunk. The only strange thing is that the wheel was invented before moonshine...

Burmeister & Wain

My first “flag” ship was the bulk carrier “Galaktik” of the Greek shipping company. This was in December 1991, when the collapse of the ChMP merchant fleet was just beginning. There were fewer and fewer jobs for sailors in the base fleet, and at the same time, getting “under the flag” was not yet available to everyone. The Soviet tails of the selection principle were still rubbing tightly against the ground: where he got through by acquaintance, where he poured out the number...
I ended up in this elite guard completely by accident. The decision had already been made, and all that remained was to go to the personnel to sign an application for transfer to the “flag” fleet. The inspector, of course, categorically refused me, saying that there was no one to work on tankers. On the way out, I noticed that the door to the office of the senior inspector (I don’t remember the last name, there were a lot of them at that time in Nakhimov Lane), head. personnel of the flag fleet is open and there is no secretary in the dressing room. I decided on a rash, but, as it turned out later, the right thing and, knocking, asked permission to enter. Only the table lamp was burning in the office, and in its light I saw the face of a busy man. He took off his glasses.
- I'm listening to you, young man.
- I have a problem, I wanted to get some advice.
- I do not have much time. What do you have?
- I wrote an application, I want to fly the flag...
- Let's make a statement. Where is the inspector's signature?
- That’s the thing, the inspector doesn’t want to sign, he won’t let me go.
There was a slight pause. The gaze jumped from the page to me and back. His hand put the glasses on his nose, rubbed them tightly against the bridge of his nose, and some other, firm voice said:
- And we can do without his signature! - the hand sweepingly approved some resolution on paper, the other, rummaging in the desk drawer, took out a small seal from its depths, and its categorical clap threw me into another world...

The first gatherings of flag guards were right there, in the personnel of what seemed to be the ChMP. Although it was already clear to many in those days that these three letters were drowning in the quagmire of capitalist renewal. But then the sailor was worried about something else - making money. And who is destroying what there and who will end up under the ruins - empty talk through cigarette smoke over a mug of garbage beer in a diner next to the footage. My own - it’s somehow closer and more painful... So, already knowing the name of the ship on which I was to fly as part of a assembled crew to an unknown destination and when, I regularly, three times a week, attended training camps at the appointed time. The issues that were resolved there, at first glance, were serious and urgent, but upon closer examination it turned out that this was simply re-staffing, weeding out those undesirable and squeezing in new people who were needed by someone, but as it often turned out, completely unnecessary on the ships. Among all the others, there were many truly serious specialists with extensive experience and experience working on Soviet ships - both ordinary sailors and officers. This is how I met two outstanding personalities: Boris Ivanovich Maslyuk and Ivan Ivanovich Volkov. Old welders-motor operators, ordinary hard-working sailors Borya and Vanya, whom I immediately christened after the type of ship’s main engine - Burmeister and Vine...

Old pants with new holes

Panama greeted us with heat, and somewhere there the houses creaked in winter. They brought us from the airport straight to the Panama Canal, near the glorious city of the same name. We had to wait several hours for the ship to change crew. Immediately, local merchants (in common parlance - businessmen) came to us with all sorts of obsessive offers to buy their various goods. Among other things, they could also find something useful. For example, vodka.

It was bought in the amount of two boxes, each of which contained six two-liter bottles called “BOLSHOY VODKA.” And TVs. I couldn’t claim such luxury, since I flew out of Odessa empty-handed and landed in Panama with holes in my pockets. But some people still had the number crunching loudly in their pockets, and three of our well-hungover comrades categorically decided: we must take it! The non-drinking Burmeister joined them, having used his brains and reasoned that a TV in the cabin for the duration of the contract was a thing of paramount importance. Vine modestly broke away, deciding to buy a TV on the way home after the end of his contract... or better yet, a stereo system.

Having agreed with the merchant, who, to celebrate, reduced the price for wholesale from four hundred to as much as three hundred and eighty dollars per unit of goods, our husbands were now completely ready to work for at least a year and even on a damn trough that would float in boiling oil. The devices were tested by plugging the plugs into a socket one at a time in a greasy booth that stank of fish and old flip-flops.

The purchases were washed. While waiting for the ship to arrive, the number of boxes of vodka was reduced to one and a half. Someone bought himself a straw hat, which after about five minutes irresponsibly trusted the light breeze...

Three finger figure

It was already the third month of the contract. Fulfilling the terms of the charter, the ship ran with a cargo of coal, ore or cement, and sometimes grain, from ports on the Mississippi, across the Atlantic, to the Gulf of Guinea. Back in ballast again to the States. It's hot in the tropics, and the air conditioning on the ship doesn't work. Total savings - the company is tight on spare parts, and Vine and I take it apart, come up with something, put it back together... It will work for a couple of days and it will turn sour. But we are no strangers.
One day, leaving the glorious Guinean port of Conakry, we once again moved to New Orleans. According to international requirements, before leaving such cheerful ports, the crew must inspect the entire ship for the presence of illegal migrants in various holes and crevices and, if found, hand them over to the authorities. They inspected us as usual, that is, not very carefully. And in the half hour allotted time you won’t be able to watch much. Here we need a couple of hours and more flashlights. In general, on the third day of the passage, three keys hatched from somewhere in the hold. Hello, they say, we really want to drink here, and we wouldn’t mind eating. And it’s dark there!.. They gave you something to drink, gave you bread, and assigned the kind people to a cabin with bars on the porthole and locked them up. In the cabin, as expected, there is a latrine and a washbasin. But our younger brothers probably had never heard of the miracles of everyday life and relieved themselves in the corners of the cabin. In all the languages accessible to the crew members, using our fingers and toes, we tried to explain where to go when needed, but it turned out to be hopeless, except that our godchildren began to use only one corner of the cabin out of four. And that’s already good...

Meanwhile, there is an intense correspondence between the captain and the company regarding the presence on board of unwanted elements who intend to undermine the economy of the United States with their secret invasion. From America itself there are dissatisfied and categorical statements that the blame for the incident lies with the captain and crew and that penalties will be applied to the company. The captain, in turn, gathers the crew for the investigation...

I only remember the captain’s last name: Morokov. I won’t judge the master’s qualities - it’s not my level. But he was a professional, you could feel it. And as a person, we all have our own bursting balloons in our heads and family problems. He had a peculiar style of conversation - an accelerated stutter, and in a nervous or tense environment he could sometimes not be understood; he had to listen.
- So, Captain Morokov gathered the people for reprisals. He sits at the table, red as a beet, spluttering with saliva, knocking on the table with his fist in time with the cut words:

The company must pay a fine, sh-fine for these p-passengers! Because of your s-negligence! They're going to pay thousands and thousands of dollars!.. - at this time, Burmeister, sitting in the first row of the meeting, tensely, with his hand pressed to his ear, listens to Morokov's gibberish.

His face gradually moves from a state of complete misunderstanding to concentration, then his eyebrows slowly shift, one rises and stretches across his forehead... - And w-what do you want me to do with you?! They're drinking a hundred dollars! P-pay because of you!..
...the captain didn’t have time to continue ramming. Burmeister suddenly jumped up from his seat and shouted in a trembling, angry, hysterical voice:

Do I have to pay my hundred and fifty dollars?! On the! - and under Morokov’s nose a tightly coiled working hand huge fig!..
While they calmed down Burmeister, explaining to him what it was all about and what it was all about, while the stunned Morokov came to his senses, while the laughter roared in the salon, some time passed. There could be no further talk of any meeting. Boris Ivanovich was rather deaf. Yes, and stingy - that was it!

Cylinder diameter - 500 mm; piston stroke - 1620mm; the purge system is direct-flow valve.

Effective diesel power: Ne = 1214 kW

Rated rotation speed: n n = 141 min -1.

Effective specific fuel consumption at nominal mode g e = 0.170 kg/kW h.

Overall dimensions of the diesel engine:

Length (on the fundamental frame), mm 6171

Width (across the fundamental frame), mm 3770

Height, mm. 10650

Weight, t 273

A cross section of the main engine is shown in Fig. 1.1. The coolant is fresh water (in a closed system). The temperature of fresh water at the outlet of the diesel engine at steady state operation is 80...82 °C. The temperature difference at the inlet and outlet of the diesel engine is no more than 8...12°C.

The temperature of the lubricating oil at the diesel inlet is 40...50 °C, at the diesel outlet 50...60 °C.

Average pressure: Indicator - 2.032 mPa; Effective -1.9 mPa; Maximum combustion pressure - 14.2 MPa; Purge air pressure is 0.33 MPa.

The assigned resource before major repairs is at least 120,000 hours. Diesel service life is at least 25 years.

The cylinder cover is made of steel. An exhaust valve is attached to the central hole using four pins.

In addition, the cover is equipped with drillings for nozzles. Other drillings are for indicator, safety and start valves.

The central part of the crosshead is connected to the head bearing journal. The cross beam has a hole for the piston rod. The head bearing is equipped with liners that are filled with babbitt.

The crankshaft is semi-composite. The frame bearings receive oil from the main lube oil line. The thrust bearing serves to transmit the maximum thrust of the propeller through the propeller shaft and intermediate shafts. The thrust bearing is installed in the aft section of the fundamental frame. The lubricating oil for lubrication of the thrust bearing comes from the pressure lubrication system.

The camshaft consists of several sections. Sections are connected using flange connections.

Rice.

The piston consists of two main parts: the head and the skirt. The piston head is bolted to the top ring of the piston rod. The piston skirt is attached to the head with 18 bolts.

Types of fuels and oils used

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Selection of fuel and oil with analysis of the influence of their characteristics on rAbot

Oils used

Cylinder oil must meet the following requirements:

- have the ability to neutralize acids formed as a result of fuel combustion and protect working surfaces from corrosion;

- prevent deposits of carbon deposits on pistons, cylinders and windows;

- have high strength lubricant film at high pressures and temperatures;

- do not produce combustion products harmful to engine parts;

- be stable when stored in ship conditions and insensitive to water

Lubricating oils must meet the following requirements:

- have an optimal of this type viscosity;

- have good lubricity;

- be stable during operation and storage;

- have, if possible, minimal tendency to carbon deposits and varnish formation;

- must not have a corrosive effect on parts;

- must not foam or evaporate.

To lubricate the cylinders of crosshead diesel engines, special cylinder oils for sulfur fuels with detergent and neutralizing additives are produced.

Due to the significant increase in supercharging of diesel engines, the problem of increasing engine service life can only be solved by choosing the optimal lubrication system and the most effective oils and their additives.

Selection of fuel and oils

Elf

B.P.

Castrol

Chevron

Exxon

Mobile

Shell

Atlanta marine D3005

Energol OE-HT30

Marine CDX30

Veritas 800 Marine

Exxmar XA

Alcano 308

Melina 30/305

Talusia XT70

CLO 50-M

Install the control levers in

“Start” position to reverse (brake with air). After stopping the diesel engine, set the lever to the “Stop” position

Switch fuel system

Faulty injectors and fuel

Immediately turn off the fuel and

Switch fuel system

to receive from another supply tank, drain water from the supply tank

Bibliography

1. Vanscheidt V.A., Design and strength calculations of marine diesel engines, L. "Shipbuilding" 1966

2. Samsonov V.I., Marine internal combustion engines, M "Transport" 1981

3. Handbook of ship mechanics. Volume 2. Generally edited by L.L. Gritsaya.

4. Fomin Yu.Ya., Marine internal combustion engines, L.: Shipbuilding, 1989

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