Systems for changing the engine compression ratio. Piston internal combustion engine with variable compression ratio Features of the compression variable system

Closely related to efficiency. In gasoline engines, the compression ratio is limited to detonation combustion. These restrictions are of particular importance for engine operation at full load, while at partial load the high compression ratio does not pose a risk of detonation. To increase engine power and improve efficiency, it is desirable to reduce the compression ratio, but if the compression ratio is low across all engine operating ranges, this will lead to reduced power and increased fuel consumption at part loads. In this case, the compression ratio values, as a rule, are chosen much lower than those values at which the most economical engine performance is achieved. Knowingly worsening the efficiency of engines, this is especially pronounced when operating at partial loads. Meanwhile, a decrease in the filling of the cylinders with the combustible mixture, an increase in the relative amount of residual gases, a decrease in the temperature of parts, etc. create opportunities to increase the compression ratio at partial loads in order to improve engine efficiency and increase its power. To solve this compromise problem, engine options with variable compression ratios are being developed.

Widespread use in engine designs has made this direction of work even more relevant. The fact is that with supercharging, the mechanical and thermal loads on engine parts increase significantly, and therefore they have to be strengthened, increasing the weight of the entire engine as a whole. In this case, as a rule, the service life of parts operating under more loaded conditions is reduced, and engine reliability is reduced. In the case of a transition to a variable compression ratio, the operating process in the engine during supercharging can be organized in such a way that, due to a corresponding reduction in the compression ratio at any boost pressure, the maximum operating cycle pressures (i.e., operating efficiency) will remain unchanged or will change slightly. At the same time, despite the increase useful work per cycle, and, consequently, the engine power, the maximum loads on its parts may not increase, which makes it possible to boost the engines without introducing changes to their design.

Very essential for the normal course of the combustion process in an engine with a variable compression ratio is right choice the shape of the combustion chamber, providing the shortest path of flame propagation. The change in the flame propagation front must be very rapid in order to take into account various modes engine operation during vehicle operation. Given the use of additional parts in the crank mechanism, it is also necessary to develop systems with a low coefficient of friction so as not to lose the advantages when using a variable compression ratio.

One of the most common engine options with a variable compression ratio is shown in the figure.

Rice. Engine diagram with variable compression ratio:
1 – connecting rod; 2 – piston; 3 – eccentric shaft; 4 - additional connecting rod; 5 – connecting rod journal of the crankshaft; 6 – rocker arm

At partial loads, additional 4 occupies the lowest position and raises the piston stroke area. The compression ratio is maximum. At high loads, the eccentric on shaft 3 raises the axis of the upper head of the additional connecting rod 4. At the same time, the over-piston clearance increases and the compression ratio decreases.

In 2000, an experimental Gas engine SAAB company with variable compression ratio. His unique features allow you to reach a power of 225 hp. with a working volume of 1.6 liters. and maintain fuel consumption comparable to an engine half the size. The ability to steplessly change the displacement allows the engine to run on gasoline, diesel fuel or alcohol.

The engine cylinders and the block head are made as a monoblock, that is, as a single block, and not separately as in conventional engines. A separate block also consists of a crankcase and a connecting rod and piston group. The monoblock can move in the block crankcase. The left side of the monoblock rests on the axis 1 located in the block, which serves as a hinge; the right side can be raised or lowered using a connecting rod 3 controlled by an eccentric shaft 4. To seal the monoblock and the block crankcase, a corrugated rubber cover 2.

Rice. SAAB variable compression engine:
1 – axis; 2 – rubber cover; 3 – connecting rod; 4 – eccentric shaft.

The compression ratio changes when the monoblock is tilted relative to the crankcase by means of a hydraulic drive while the piston stroke remains unchanged. Deviation of the monoblock from the vertical leads to an increase in the volume of the combustion chamber, which causes a decrease in the compression ratio.

As the angle of inclination decreases, the compression ratio increases. The maximum deviation of the monoblock from the vertical axis is 4%.

At minimum crankshaft rotation speed and fuel supply reset, as well as at low loads, the monoblock occupies the lowest position, in which the volume of the combustion chamber is minimal (compression ratio - 14). The charging system is switched off and air flows directly into the engine.

Under load, due to rotation of the eccentric shaft, the connecting rod deflects the monoblock to the side, and the volume of the combustion chamber increases (compression ratio - 8). In this case, the clutch connects the supercharger, and air begins to flow into the engine under excess pressure.

Rice. Changing the air supply to the SAAB engine under different modes:
1 – throttle valve; 2 – bypass valve; 3 – clutch; a – at low crankshaft speed; b – at load conditions

The optimal compression ratio is calculated by the electronic system control unit taking into account the crankshaft speed, load level, type of fuel and other parameters.

Due to the need to quickly respond to changes in the compression ratio in this engine, it was necessary to abandon the turbocharger in favor of mechanical supercharging with intermediate air cooling with a maximum boost pressure of 2.8 kgf/cm2.

Fuel consumption for the developed engine is 30% less than that of a conventional engine of the same volume, and the exhaust gas toxicity indicators comply with current standards.

The French company MCE-5 Development has developed for the Peugeot-Citroen concern an engine with a variable compression ratio VCR (Variable Compression Ratio). This solution uses the original kinematics of the crank mechanism.

In this design, the transmission of motion from the connecting rod to the pistons is carried out through a double gear sector 5. C right side engine support is located rack 7, on which sector 5 rests. Such engagement ensures strictly reciprocating movement of the cylinder piston, which is connected to the rack 4. Rack 7 is connected to the piston 6 of the control hydraulic cylinder.

Depending on the operating mode of the engine, a signal from the engine control unit changes the position of the piston 6 of the control cylinder connected to the rack 7. Shifting the control rack 7 up or down changes the position of the TDC and BDC of the engine piston, and with them the compression ratio from 7:1 to 20:1 in 0.1 s. If necessary, it is possible to change the compression ratio for each cylinder separately.

Rice. Engine with variable compression ratio VCR:
1 – crankshaft; 2 – connecting rod; 3 – toothed support roller; 4 – piston rack; 5 – gear sector; 6 – piston of the control cylinder; 7 – support control rack.

Over more than a century of life, the engine internal combustion(ICE) has changed so much that only the principle of operation remains from the ancestor. Almost all stages of modernization were aimed at increasing the coefficient useful action(efficiency) of the engine. The efficiency indicator can be called universal. It contains many characteristics - fuel consumption, power, torque, composition exhaust gases etc. Widespread use of new technical ideas- fuel injection, electronic ignition and engine control systems, 4, 5 and even 6 valves per cylinder - played a positive role in increasing engine efficiency.

However, as shown Geneva Motor Show, until the process is completed engine modernization still far. At this popular international auto show SAAB company presented the result of its 15 years of work - a prototype of a new engine with a variable compression ratio - SAAB Variable Compression (SVC), which became a sensation in the world of engines.

SVC technology and a number of other advanced and non-traditional from the point of view of existing concepts of internal combustion engines technical solutions allowed us to provide the new product with fantastic characteristics. Thus, a five-cylinder engine with a volume of only 1.6 liters, created for ordinary production cars, develops an incredible power of 225 hp. and torque 305 Nm. Other characteristics that are especially important today also turned out to be excellent - fuel consumption at medium loads was reduced by as much as 30%, and CO2 emissions were reduced by the same amount. As for CO, CH and NOx, etc., they, according to the creators, comply with all existing and planned toxicity standards for the near future. In addition to this, the variable compression ratio gives the SVC engine the ability to operate on various brands of gasoline - from A-76 to Ai-98 - with virtually no deterioration in performance and eliminating the occurrence of detonation.

Of course, the significant merit of such characteristics is in SVC technology, i.e. the ability to change the compression ratio. But before we get acquainted with the design of the mechanism that made it possible to change this value, let us remember some truths from the theory of internal combustion engine design.

Compression ratio

The compression ratio is the ratio of the sum of the volumes of the cylinder and combustion chamber to the volume of the combustion chamber. With an increase in the compression ratio in the combustion chamber, the pressure and temperature increase, which creates more favorable conditions for the ignition and combustion of the combustible mixture and increases the efficiency of fuel energy use, i.e. Efficiency The higher the compression ratio, the greater the efficiency.

There are no problems with the creation of gasoline engines with a high compression ratio. And they don’t make them according to next reason. During the compression stroke of such engines, the pressure in the cylinders increases to very high values. This naturally causes an increase in temperature in the combustion chamber and creates favorable conditions for detonation to occur. And detonation, as we know (see page 26) is a dangerous phenomenon. In all engines created before this time, the compression ratio was constant and was determined depending on the pressure and temperature conditions in the combustion chamber at maximum load, when fuel and air consumption are maximum. The engine does not always operate in this mode, one might even say very rarely. On the highway or in the city, when the speed is almost constant, the motor operates at low or medium loads. In such a situation, for more efficient use of fuel energy, it would be nice to have a higher compression ratio. This problem was solved by SAAB engineers - the creators of SVC technology.

SVC technology

First of all, it should be noted that in the new engine, instead of the traditional cylinder head and cylinder liners, which were cast directly into the block or pressed, there is one monohead that combines the cylinder head and cylinder liners. To change the compression ratio, or more precisely, the volume of the combustion chamber, the monohead is made movable. On the one hand, it is mounted on a shaft that serves as a support, and on the other, it is supported and driven by a separate crank mechanism. The crank radius ensures that the head is shifted relative to the vertical axis by 40. This is quite enough to change the volume of the chamber to obtain a compression ratio from 8:1 to 14:1.

The required compression ratio is determined by the SAAB Trionic electronic engine management system, which monitors the load, speed, fuel quality and, based on this, controls the hydraulic crank drive. So, at maximum load the compression ratio is set to 8:1, and at minimum - 14:1. Combining the cylinder liners with their head, among other things, allowed SAAB engineers to give the cooling jacket channels a more advanced shape, which increased the efficiency of the process of removing heat from the walls of the combustion chamber and the cylinder liners.

The mobility of the cylinder liners and their heads required changes to the design of the engine block. The plane of the joint between the block and the head has become lower by 20 cm. As for the tightness of the joint, it is ensured by a rubber corrugated gasket, which is protected from damage by a metal casing on top.

Small, but smart

For many, it may become incomprehensible how more than two hundred “horses” were “charged” into an engine with such a small volume - after all, such power can negatively affect its service life. When creating the SVC engine, engineers were guided by completely different goals. Bringing engine life to the required standards is the job of technologists. As for the small engine volume, it was done in full accordance with the theory of internal combustion engines. Based on its laws, the most favorable treatment engine performance from the point of view of increasing efficiency - under heavy load (at high speeds) when the throttle valve is fully open. In this case, it makes maximum use of fuel energy. And since engines with a smaller displacement operate mainly at maximum loads, then their efficiency is higher.

The Secret of Excellence small engines in terms of efficiency it is explained by the absence of so-called pumping losses. They occur under light loads, when the engine is running at low speeds and the throttle valve is only slightly open. In this case, during the intake stroke, a large vacuum is created in the cylinders - a vacuum, which resists the downward movement of the piston and, accordingly, reduces efficiency. When fully open throttle valve there are no such losses, since air enters the cylinders almost unhindered.

To avoid pumping losses 100%, in the new engine SAAB engineers also used “supercharging” of air under high pressure- 2.8 atm., using a mechanical supercharger - compressor. Preference was given to a compressor for several reasons: firstly, no turbocharger is capable of creating such a boost pressure; secondly, the compressor’s response to load changes is almost instantaneous, i.e. There is no slowdown characteristic of turbocharging. Filling the cylinders with fresh charge in the SAAB engine was improved with the help of today's popular modern gas distribution mechanism, in which there are four valves for each cylinder, and thanks to the use of an intercooler.

The prototype SVC engine, according to the German engine development company FEV Motorentechnie in Aachen, is quite functional. But despite the positive assessment, it will be put into mass production some time later - after it has been finalized and fine-tuned to customer requests.

We have already written about the technology of the new Infiniti engine in our review articles. A unique model of a gasoline engine that can change the compression ratio “on the fly” can be as powerful as a regular gasoline power unit and economical as if you were driving a diesel engine.

Today Jason Fenske will explain the essence of the engine and how it achieves highest power and efficiency.

Variable compression technology, or if you want turbocharged engine with a variable compression ratio, can almost instantly change the piston pressure on the fuel-air mixture in a ratio from 8:1 before 14:1 , while offering highly efficient compression at low loads (in the city, for example, or on the highway) and the low compression required by the turbine under hard acceleration, with maximum throttle opening.

Jason, together with Infiniti, explained how the technology works, not forgetting to note the nuances and previously unknown details of the amazing innovative engine. Exclusive material can be viewed in the video that we will publish below; do not forget to turn on the translation of subtitles if necessary. But first, we will select the technical “grain” of the engine building of the future and note those nuances that were previously unknown.

The central technology of the unique motor was the system of a special rotary mechanism, which, thanks to a complex piston rod, has a central rotary multi-lever system that is capable of changing its angle of operation, which leads to a change in the effective length of the piston rod, which in turn changes the length of the piston stroke in the cylinder, which ultimately changes the compression ratio.

The drive technology in detail is as follows:

1. The electric motor turns the lever actuator 1.30 minute video

2. The lever turns the drive shaft using a similar principle to drive conventional camshafts, using a cam system.

3. Third, the lower arm changes the angle of the multi-link drive connected to upper lever. The latter is connected to the piston (1.48 minute video)

4. The entire system is at certain settings and allows the piston to change height top dead points, reducing or increasing the compression ratio.

For example, if the engine goes from “ maximum power» to the “fuel saving and efficiency increasing” mode, the wave gearbox will rotate to the left. Shown in the right photo (2.10 minutes of video). The rotation will be transmitted to the drive shaft, which will pull the lower arm down slightly, which will raise the multi-link drive, which in turn will move the piston closer to the cylinder head, reducing volume and thereby increasing compression.

Additionally, there is a transition from the traditional Otto internal combustion engine operating cycle to the Atkinson cycle, which differs in the ratio of cycle cycle times, which is achieved by changing the closing time of the intake valves.

By the way, according to Fenske, the transition from one mode of engine operation to another takes no more than 1.2 seconds!

Moreover, the new technology is able to vary the compression ratio over the entire range from 8:1 to 14:1, permanently adapting to driving style, load and other factors affecting engine performance.

But even explaining how such complex technology works is not the end of the story. Another important characteristic of the new engine is the reduction of piston pressure on the cylinder walls, which will avoid ovalization of the latter, since in conjunction with the piston drive system, a system is used to reduce the friction of the piston on the cylinder walls, which acts by reducing the angle of attack of the connecting rod during the piston stroke.

The video noted that the inline four-cylinder engine, due to its design, was somewhat unbalanced, so engineers were forced to add a balance shaft, which complicates the engine design, but leaves it a chance to long life without the deadly vibrations that arise due to the operation of a complex connecting rod.

The invention relates to mechanical engineering, primarily to heat engines, namely to a piston internal combustion engine (ICE) with a variable compression ratio. The technical result of the invention is to improve the kinematics of the force transmission mechanism of a piston internal combustion engine, in such a way as to provide the ability to regulate the compression ratio while simultaneously reducing the reaction in the supports and second-order inertia forces. The internal combustion engine according to the invention has a piston movably installed in the cylinder, which is pivotally connected to a connecting rod. The movement of the connecting rod is transmitted to the crankshaft crank. At the same time, in order to provide the possibility of controlled changes in the compression ratio and piston stroke, a transmission link is provided between the connecting rod and the crank, which is configured to control its movement using a control lever. The transmission link is made in the form of a transverse lever connected to the crank via a hinge, which is located in an intermediate position in the area between two support points. At one of the support points, the transverse lever is connected to the connecting rod, and at the other, to the control lever. The control lever is also pivotally connected to an additional crank or eccentric, which carry out control movements by shifting the swing axis of the control lever, thereby ensuring a change in the degree internal combustion engine compression. In addition, the swing axis of the control lever can perform a continuous cyclic movement synchronized with the rotation of the crankshaft. At the same time, if certain geometric relationships between individual links of the force transmission mechanism are observed, the load on them can be reduced and the smooth operation of the internal combustion engine can be increased. 12 salary f-ly, 10 ill.

Drawings for RF patent 2256085

The present invention relates to mechanical engineering, primarily to heat engines. The invention relates, in particular, to a piston internal combustion engine (ICE) having a piston, which is movably installed in the cylinder and which is pivotally connected to a connecting rod, the movement of which is transmitted to the crank of the crankshaft, while a transmission link is provided between the connecting rod and the crank, which is made with the ability to control its movement using a control lever in order to ensure controlled movement of the piston, primarily to provide the ability to change the degree of compression and stroke of the piston, and which is made in the form of a transverse lever that is connected to the crank by a hinge, which is located in an intermediate position in the area between the supporting a point at which the wishbone is connected to the connecting rod, and a reference point at which the wishbone is connected to the control arm, and at some distance from a line connecting both of these support points at which the wishbone is connected to the control arm and the connecting rod, respectively.

From Wirbeleit F.G., Binder K. and Gwinner D., "Development of Piston with Variable Compression Height for Incrising Efficiency and Specific Power Output of Combustion Engines", SAE Techn. Pap., 900229, an internal combustion engine of this type with an automatically variable compression ratio (PARSS) is known by changing the height of the piston, which consists of two parts, between which hydraulic chambers are formed. The compression ratio is changed automatically by changing the position of one part of the piston relative to the other by transferring oil from one such chamber to another using special bypass valves.

The disadvantages of this technical solution include the fact that PARSS-type systems require the presence of a compression ratio control mechanism located in a high-temperature and highly loaded area (in the cylinder). Experience with PARSS-type systems has shown that in transient conditions, in particular when accelerating a car, the operation of the internal combustion engine is accompanied by detonation, since hydraulic system control does not allow for rapid and simultaneous changes in the compression ratio across all cylinders.

The desire to remove the mechanism for regulating the compression ratio from the high-temperature and mechanically loaded zone has led to the emergence of other technical solutions that involve changing the kinematic diagram of the internal combustion engine and introducing additional elements (links) into it, the control of which ensures a change in the compression ratio.

For example, Jante A., “Kraftstoffverbrauchssenkung von Verbrennungsmotoren durch kinematische Mittel”, Automobil-Industrie, No. 1 (1980), pp. 61-65, describes an internal combustion engine (the kinematic diagram of which is shown in Fig. 1), of which two are installed between the crank 15 and the connecting rod 12 intermediate links- additional connecting rod 13 and rocker arm 14. Rocker arm 14 makes a rocking motion with the center of swing at the hinge point Z. The degree of compression is adjusted by changing the position of point A by rotating the eccentric 16 mounted on the body. The eccentric 16 rotates depending on the engine load, while the center of swing, located at the hinge point Z, moves along a circular arc, thus changing the position of the top dead center of the piston.

From the work of Christoph Bolling et al., "Kurbetrieb fur variable Verdichtung", MTZ 58 (11) (1997), pp. 706-711, an FEV type engine (the kinematic diagram of which is shown in Fig. 2) is also known, in which between the crank 17 and the connecting rod 12, an additional connecting rod 13 is installed. The connecting rod 12, in addition, is connected to the rocker arm 14, which performs a rocking motion with the swing center at the hinge point Z. The degree of compression is adjusted by changing the position of the hinge point Z by rotating the eccentric 16 mounted on engine housing. The eccentric 16 rotates depending on the engine load, while the center of swing, located at the hinge point Z, moves along a circular arc, thus changing the position of the top dead center of the piston.

From the application DE 4312954 A1 (04/21/1993) an IFA type engine is known (the kinematic diagram of which is shown in Fig. 3), in which an additional connecting rod 13 is installed between the crank 17 and the connecting rod 12. The connecting rod 12 is also connected to one of the ends of the rocker arm 14, the second end of which performs a rocking motion with the center of swing at the hinge point Z. The compression ratio is adjusted by changing the position of the hinge point Z by rotating the eccentric 16, which is fixed to the engine body. The eccentric 16 rotates depending on the engine load, while the center of swing, located at the hinge point Z, moves along a circular arc, thus changing the position of the top dead center of the piston.

The disadvantages inherent in the engines of the above-described designs (known from the work of Jante A., from the work of Christoph Bolling et al. and from the application DE 4312954 A1) include, first of all, the insufficient smoothness of their operation, due to high second-order inertia forces during reciprocating translational movement of masses, which is associated with the peculiarities of the kinematics of mechanisms and leads to an excessive increase in the total width or total height power unit. For this reason, such engines are practically unsuitable for use as vehicle engines.

Regulating the compression ratio in a piston internal combustion engine allows you to solve the following problems:

Increase the average pressure Pe by increasing the boost pressure without increasing maximum pressure combustion beyond specified limits by reducing the compression ratio as engine load increases;

Reduce fuel consumption in the range of low and medium loads by increasing the compression ratio as the engine load decreases;

Improve engine smoothness.

Adjustment of the compression ratio allows depending on ICE type achieve the following advantages (for internal combustion engines with forced (spark) ignition):

While maintaining the achieved level of engine efficiency at low and medium loads, a further increase in the rated engine power is ensured by increasing the boost pressure while decreasing the compression ratio (see Fig. 4a, where the curves designated by x refer to regular engine, and the curves marked with the position y refer to an engine with a variable compression ratio);

While maintaining the achieved level of rated engine power, a reduction in fuel consumption at low and medium loads is ensured by increasing the compression ratio to the permissible detonation limit (see Fig. 4b, where the curves marked with the position x refer to a conventional engine, and the curves marked with the position y, refer to an engine with a variable compression ratio);

While maintaining the achieved level of rated engine power, efficiency increases at low and medium loads, and also reduces the engine noise level while simultaneously reducing the rated crankshaft speed (see Fig. 4c, where the curves indicated by x refer to a conventional engine, and the curves , indicated by the position y, refer to an engine with a variable compression ratio).

Similar to internal combustion engines with spark ignition The compression ratio in a diesel engine can be controlled in the following three equal directions:

With a constant displacement and rated speed, the engine power is increased by increasing the boost pressure. In this case, it is not the efficiency that increases, but the power vehicle(See FIG. 5a, where the curves labeled x are for a conventional engine and the curves labeled y are for a variable compression ratio engine);

With a constant working volume and rated power, the average pressure Pe is increased with a decrease in the rated speed. In this case, while maintaining the power characteristics of the vehicle, engine efficiency increases due to increased mechanical efficiency (see Fig. 5b, where the curves designated by x refer to a conventional engine, and the curves designated by y refer to an engine with a variable compression ratio );

The existing large displacement engine is not replaced with a small displacement engine of the same power (see Fig. 5c, where the curves labeled x refer to a conventional engine, and the curves labeled y refer to an engine with a variable compression ratio ). In this case, the engine efficiency increases in the range of medium and full loads, and the weight and dimensions of the engine are reduced.

The basis of the present invention was the task of improving the kinematics of a piston internal combustion engine in such a way that, at low design costs, it would be possible to regulate the compression ratio while simultaneously reducing the reaction in the supports and second-order inertia forces.

With regard to a piston internal combustion engine of the type indicated at the beginning of the description, this problem is solved according to the invention due to the fact that the length of the side located between the support point at which the transverse arm is connected to the control lever and the support point at which the transverse arm is connected to the connecting rod, the length of the side, located between the support point at which the wishbone is connected to the control arm and the hinge at which the wishbone is connected to the crank, and the length of the side located between the support point at which the wishbone is connected to the connecting rod and the hinge at which the wishbone is connected to the crank , satisfy the following relations in terms of the crank radius:

According to one of the preferred embodiments of the piston internal combustion engine proposed in the invention, the transverse lever is made in the form of a triangular lever, at the vertices of which there are support points at which the transverse lever is connected to the control lever and connecting rod, and a hinge by which the transverse lever is connected to the crank.

It is preferable that the length l of the connecting rod and the length k of the control lever, as well as the distance e between the axis of rotation of the crankshaft and the longitudinal axis of the cylinder, satisfy the following relations in terms of the radius r of the crank:

In the case where the control lever and the connecting rod are located on the same side of the transverse link, the distance f between the longitudinal axis of the cylinder and the hinge point of the control lever with the engine body and the distance p between the axis of the crankshaft and the specified hinge point should preferably satisfy in terms of radius r crank to the following ratios:

In the same case, when the control lever and connecting rod are located along different sides transverse lever, the distance f between the longitudinal axis of the cylinder and the hinge point of the control lever and the distance p between the axis of the crankshaft and the specified hinge point should preferably satisfy, in terms of the radius r of the crank, the following relationships:

According to a further preferred embodiment of the piston internal combustion engine according to the invention, the articulation point of the control lever can be moved along a controlled path.

It is also preferable to provide the possibility of fixing the pivot point of the control arm in various adjustable angular positions.

In accordance with another preferred embodiment of the piston internal combustion engine proposed in the invention, it is possible to regulate the angular position of the pivot point of the control lever depending on the values characterizing the operating mode of the internal combustion engine and the operating parameters of the internal combustion engine.

According to another preferred embodiment of the piston internal combustion engine proposed in the invention, it is possible to move the articulation point of the control lever along a controlled path, synchronized with the rotation of the crankshaft.

In another preferred embodiment of the piston internal combustion engine proposed in the invention, it is possible to synchronize with the rotation of the crankshaft the movement of the hinge point of the control lever along a controlled path and the ability to regulate the phase shift between the movement of this point and the rotation of the crankshaft, depending on the values characterizing the operating mode of the internal combustion engine and operating parameters ICE.

In accordance with the next preferred embodiment of the piston internal combustion engine proposed in the invention, it is possible to synchronize with the rotation of the crankshaft the movement of the hinge point of the control lever along a controlled path, and it is possible to change the transmission ratio between the movement of this point and the rotation of the crankshaft.

The piston internal combustion engine 1 proposed in the invention is shown in Figs. 6a and 6b and has a housing 2 with a cylinder 3 and a piston 4 installed in it, a connecting rod 6, which is pivotally connected at one end to the piston 4, a crank 8 of the crankshaft installed in the housing 2, trailed connecting rod 10, also called control lever 10 and pivotally connected at one end to the body 2, and a triangular transverse lever 7, which with one of its vertices is pivotally connected to the second end of the connecting rod 6, its second vertex is pivotally connected to the crank 8, and its third vertex is pivotally connected connected to the trailing connecting rod 10. To regulate the degree of compression, the swing axis of the trailing connecting rod 10, i.e. the Z point of its hinge joint has the ability to move along a controlled trajectory, determined, for example, by an eccentric or an additional crank 11.

Depending on the position of the swing axis of the trailing connecting rod, the piston internal combustion engine proposed in the invention has two options design(see Figs. 6a and 6b):

In the first embodiment (Fig. 6a), the horizontal plane in which the swing axis of the trailing connecting rod 10 lies, i.e. the Z point of its articulation is located above the connection point of the crank 8 with the transverse arm 7 when the crank is at its top dead center or, in other words, the trailing connecting rod 10 and the connecting rod 6 are located on one side of the transverse arm 7;

In the second option (Fig. 6b), the horizontal plane in which the swing axis of the trailing connecting rod 10 lies, i.e. the Z point of its hinge connection is located below the connection point of the crank 8 with the transverse lever 7 when the crank is at its top dead center or, in other words, the trailing connecting rod 10 and the connecting rod 6 are located on opposite sides of the transverse lever 7.

Changing the position of the Z point of the hinge joint of the trailing arm, i.e. its swing axis, allows, due to a simple control movement carried out by an additional crank, respectively a regulating eccentric, to change the compression ratio. In addition, the Z point of the articulated connection of the trailing arm, i.e. its swing axis can perform a continuous cyclic movement synchronized with the rotation of the crankshaft.

As shown in Fig. 7, the piston internal combustion engine proposed in the invention has significant advantages over known systems (described by Jante A., Christoph Bolling et al. and DE 4312954 A1), as well as over the conventional crank mechanism (CM) regarding the smoothness of its operation.

However, these advantages can only be achieved if certain geometric relationships are observed, namely, when correct selection the lengths of individual elements and their positions relative to the axis of the crankshaft.

According to the present invention important has a determination of the dimensions of individual elements (relative to the radius of the crank) and the coordinates of individual hinges of the force transmission mechanism, which can be achieved by optimizing such a mechanism through kinematic and dynamic analysis. The goal of optimizing such a mechanism, described by nine parameters (Fig. 8), is to reduce the forces (loads) acting on its individual links to a minimum possible level and in improving the smoothness of its operation.

Below with reference to Fig.9 (9a and 9b), which shows the kinematic internal combustion engine diagram, shown in Fig. 6 (6a and 6b, respectively), explains the principle of operation of the adjustable crank mechanism. During operation of the internal combustion engine, its piston 4 performs a reciprocating movement in the cylinder, which is transmitted to the connecting rod 6. The movement of the connecting rod 6 is transmitted through the support (hinge) point B to the transverse lever 7, the freedom of movement of which is limited due to its connection with the trailing connecting rod 10 in reference (hinge) point C. If the point Z of the hinge connection of the trailing connecting rod 10 is stationary, then the reference point C of the transverse arm 7 can move along an arc of a circle, the radius of which equal to length trailed connecting rod 10. The position of such a circular trajectory of movement of the reference point C relative to the engine body is determined by the position of point Z. When the position of point Z of the hinged connection of the trailed connecting rod changes, the position of the circular trajectory along which the reference point C can move changes, which allows influencing the trajectories of movement of other elements crank mechanism, primarily on the TDC position. piston 4. The Z point of the trailing connecting rod pivot joint preferably moves along a circular path. However, the Z point of the hinge connection of the trailing connecting rod can also move along any other specified controlled trajectory, and it is also possible to fix the Z point of the hinge connection of the trailing connecting rod in any position of the trajectory of its movement.

The transverse lever 7 is also connected by hinge A to the crank 8 of the crankshaft 9. This hinge A moves along a circular path, the radius of which is determined by the length of the crank 8. Hinge A occupies an intermediate position when viewed along the line connecting the reference points B and C of the transverse lever 7. Availability kinematic connection reference point C with a trailing connecting rod 10 allows you to influence its translational movement along the longitudinal axis 5 of the piston 4. The movement of the reference point B along the longitudinal axis 5 of the piston is determined by the trajectory of the reference point C of the transverse lever 7. The influence on the movement of the reference point B allows you to control the reciprocating movement of the piston 4 through the connecting rod 6 and thereby adjust the position of the T.M.T. piston 4.

In the embodiment shown in Fig.9a, the trailing connecting rod 10 and the connecting rod 6 are located on one side of the transverse arm 7.

By turning the control link, made in the form of an additional crank 11, from the approximately horizontal position shown in Fig. 9a, for example, to a position facing vertically downwards, it is possible to shift the position of the T.M.T. piston 4 upward and thereby increase the compression ratio.

Fig. 9b shows a kinematic diagram of an internal combustion engine made according to another variant, which differs from the diagram shown in Fig. 9a only in that the trailing connecting rod 10, together with the control link made in the form of an additional crank 11, respectively, the regulating eccentric, and the connecting rod 6 are located on different sides of the transverse lever 7. In all other respects, the principle of operation of the crank mechanism shown in Fig.9b is similar to the principle of operation of the crank mechanism shown in Fig.9a, in which the trailing connecting rod 10 and connecting rod 6 are located on one side of the transverse lever 7.

Figure 10 shows another kinematic diagram of the crank mechanism of a piston internal combustion engine, which shows the positions of certain points of this crank mechanism and on which the optimal areas are indicated by shading, within which, taking into account the above-mentioned optimal ranges of values for the lengths and positions of the elements of the crank mechanism, the support point B of the swivel joint of the transverse arm 7 with the connecting rod 6, the support point C of the swivel connection of the transverse arm 7 with the towed connecting rod 10 and the point Z of the swivel connection of the towed connecting rod 10 can move. To ensure especially smooth operation For an internal combustion engine with an exceptionally low load on individual elements and links of its crank mechanism, the geometric parameters (length and position) of the elements and links of this crank mechanism must satisfy certain, preferred relationships. The lengths of the sides a, b and c of the triangular wishbone 7, where a denotes the length of the side located between the reference point B of the connecting rod and the reference point C of the trailing connecting rod, b denotes the length of the side located between the hinge A of the crank and the reference point C of the trailing connecting rod, and c denotes the distance between the hinge A of the crank and the reference point B of the connecting rod, can be described by the following inequalities depending on the radius r, which is equal to the length of the crank 8:

The length l of the connecting rod 6, the length k of the trailing connecting rod 10 and the distance e between the axis of rotation of the crankshaft 9 and the longitudinal axis 5 of the cylinder 3, which is also the longitudinal axis of the piston moving in this cylinder, according to the preferred embodiment, satisfy the following relationships:

For the variant shown in Fig. 9a, in which the connecting rod 6 and the trailing connecting rod 10 are located on one side of the transverse arm 7, it is also possible to set the optimal size ratio. In this case, the distance f between the longitudinal axis 5 of the cylinder and the point Z of the swivel connection of the trailing lever 10 to its control link, as well as the distance p between the axis of the crankshaft and the specified point Z of the swivel joint, according to the preferred embodiment, satisfy the following relationships:

When the trailing connecting rod and the connecting rod are located on opposite sides of the transverse lever, the optimal distance f between the longitudinal axis of the piston and the Z point of the hinge connection of the trailing lever to its control link, as well as the optimal distance p between the axis of the crankshaft and the specified point Z of the hinge connection can be selected based on the following ratios:

CLAIM

1. A piston internal combustion engine (ICE) having a piston (4), which is movably installed in the cylinder and which is pivotally connected to a connecting rod (6), the movement of which is transmitted to the crank (8) of the crankshaft (9), while between the connecting rod ( 6) and the crank (8) a transmission link is provided, which is configured to control its movement using a control lever (10) in order to ensure controlled movement of the piston, primarily to provide the ability to change the compression ratio and stroke of the piston, and which is made in the form of a transverse lever (7), which is connected to the crank (8) by a hinge (A), which is located in an intermediate position in the area between the support point (B), in which the transverse arm (7) is connected to the connecting rod (6), and the support point (C) , in which the transverse lever (7) is connected to the control lever (10), and at some distance from the line connecting both of these reference points (B, C), in which the transverse lever (7) is connected to the control lever (10) and connecting rod (6), respectively, characterized in that the length of the side (a) located between the reference point (C), in which the transverse lever (7) is connected to the control lever (10), and the reference point (B), in which the transverse the lever (7) is connected to the connecting rod (6), the length of the side (b) located between the support point (C) at which the wishbone (7) is connected to the control arm (10), and the hinge (A) by which the cross arm ( 7) is connected to the crank (8), and the length of the side (c) located between the support point (B) at which the wishbone (7) is connected to the connecting rod (6), and the hinge (A) to which the cross arm (7) connected to the crank (8), satisfy the following relations in terms of the radius (r) of the crank:

6. Piston internal combustion engine according to claim 4 or 5, characterized in that the point (Z) of the articulated connection of the control lever (10) can move along a controlled path.

7. A piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to adjust the position of the point (Z) of the swivel joint of the control lever (10) using an additional crank resting on the hinge.

8. Piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to adjust the position of the point (Z) of the articulated joint of the control lever (10) using an eccentric.

9. Piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to fix the point (Z) of the articulated joint of the control lever (10) in various adjustable angular positions.

10. Piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to regulate the angular position of the point (Z) of the swivel joint of the control lever (10) depending on the values characterizing the operating mode of the internal combustion engine and the operating parameters of the internal combustion engine.

11. Piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to move the point (Z) of the articulated joint of the control lever (10) along a controlled path, synchronized with the rotation of the crankshaft.

12. A piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to synchronize with the rotation of the crankshaft (9) the movement of the point (Z) of the swivel joint of the control lever (10) along a controlled path and the ability to regulate the phase shift between the movement of this point ( Z) and rotation of the crankshaft (9) depending on the values characterizing the operating mode of the internal combustion engine and operating parameters of the internal combustion engine.

13. A piston internal combustion engine according to claim 4 or 5, characterized in that it is possible to synchronize with the rotation of the crankshaft (9) the movement of the point (Z) of the swivel joint of the control lever (10) along a controlled path, while it is possible to change the transmission ratio between the movements indicated point (Z) and rotation of the crankshaft (9).

The unique technology for changing the compression ratio represents a real breakthrough in engine engineering - the 2-liter VC-Turbo constantly changes characteristics, adjusting the compression ratio for optimal power output and maximum fuel efficiency. In terms of traction characteristics, this 2-liter gasoline turbo engine is quite comparable with advanced turbodiesel engines the same working volume.

The VC-Turbo engine constantly and completely unnoticed by the driver changes the compression ratio using a system of levers that raise or lower the top dead center (TDC) of the pistons, thereby allowing best characteristics power and efficiency.

A high compression ratio, in principle, makes the engine more efficient, but in certain modes there is a risk of explosive combustion (detonation). On the other hand, a low compression ratio avoids detonation and develops high power and torque. When driving, the VC-Turbo engine's compression ratio varies from 8:1 (for maximum performance) to 14:1 (for minimal fuel consumption), underscoring INFINITI's driver-focused philosophy.

INFINITI’s VC-Turbo engine is the world’s first production-ready variable compression ratio engine – and it makes its production debut on the new QX50. This unique variable compression technology represents a breakthrough in combustion engine design – the QX50’s 2.0-liter VC-Turbo continuously transforms, adjusting its compression ratio to optimize power and fuel efficiency. It combines the power of a 2.0-liter turbocharged gasoline engine with the torque and efficiency of an advanced four-cylinder diesel engine.

The unique combination of dynamics and efficiency turns the VC-Turbo into a real alternative to modern turbodiesels, not in words, but in deeds refuting the idea that only hybrid and diesel power units can provide high torque and efficiency. VC-Turbo develops 268 hp. (200 kW) at 5600 rpm and 380 Nm at 4400 rpm, which is the best combination of power and torque among four-cylinder engines. The VC-Turbo's power-to-weight ratio is higher than that of many competing turbo engines and comes close to that of some petrol V6s. The single-flow turbocharger guarantees an immediate engine response to increased fuel supply.

The new INFINITI QX50 with VC-Turbo engine is the most efficient vehicle in its class with unrivaled fuel economy. The front-wheel drive version consumes just 8.7 L/100 km on the combined cycle, which is 35% better than the QX50. previous generation with V6 engine. All-wheel drive version premium crossover with an average consumption of 9.0 l/100 km, it is 30% more efficient than its predecessor.

Other obvious advantages of the new motor design include: compact dimensions and reduced weight. The block and cylinder head are cast from lightweight aluminum alloy, and the compression control system components are made from high-carbon steel. As a result, compared to the 3.5-liter INFINITI VQ Series engine, the new VC-Turbo weighs 18 kg less and also takes up less space in the engine compartment.

A lever system, an electric motor and a unique wave reduction gearbox are responsible for changing the compression ratio in the VC-Turbo engine. The electric motor is connected to the control lever through a gearbox. The gearbox rotates, turning the control shaft in the cylinder block, which in turn changes the position of the rocker arms through which the pistons drive the crankshaft. The tilt of the rocker arms changes the position of the top dead center of the pistons, and with it the compression ratio. An eccentric control shaft regulates the compression ratio in all cylinders simultaneously. As a result, not only the compression ratio varies, but also the engine displacement ranging from 1997 cm3 (8:1) to 1970 cm3 (14:1).

The VC-Turbo engine also seamlessly switches between the standard Otto duty cycle and the Atkinson cycle, further increasing power and efficiency. The Atkinson cycle is traditionally used to improve the efficiency of hybrid power plants. When the internal combustion engine operates according to the Atkinson cycle, the intake valves close, allowing the working mixture in the cylinders to expand more strongly, burning with greater efficiency. The INFINITI engine operates on the Atkinson cycle at high rates compression ratio, when, due to the longer stroke of the pistons, the intake valves remain open for a short time already in the compression phase.

INFINITI’s VC-Turbo engine is the world’s first production-ready variable compression ratio engine and it makes its production debut on the new QX50. This unique variable compression technology represents a breakthrough in combustion engine design the QX50’s 2.0-liter VC-Turbo continually transforms, adjusting its compression ratio to optimize power and fuel efficiency. It combines the power of a 2.0-liter turbocharged gasoline engine with the torque and efficiency of an advanced four-cylinder diesel engine.

When the VC-Turbo compression ratio is reduced, the engine returns to normal operating mode (Otto cycle), with exhaust, compression, combustion and exhaust phases clearly separated - thus achieving higher power output from the power unit.

Besides variable degree compression in the VC-Turbo engine is used and a number of other advanced technologies INFINITI. The optimal balance between efficiency and power is ensured by both the system distributed injection(MPI) and direct (GDI):

GDI improves combustion efficiency by preventing engine knock at high compression ratios
MPI, in turn, prepares in advance fuel mixture, providing it complete combustion in cylinders at low loads

At certain speeds, the engine independently switches from one injection system to another, and at maximum loads they can operate simultaneously.

The single-scroll turbocharger improves engine power and efficiency, delivering quick throttle response at all speeds and compression ratios. Thanks to turbocharging, the output of the engine is comparable to a six-cylinder atmospheric engine. The single-flow supercharger is compact and has reduced losses of thermal energy and exhaust gas pressure.

Integrated into aluminum cylinder head an exhaust manifold also improves engine efficiency and determines its compact dimensions. This solution allowed INFINITI engineers to place catalytic converter immediately behind the turbine, thus shortening the path of the exhaust gases. Thanks to this, the converter warms up faster after starting the engine and reaches operating mode earlier.

Variable compression ratio technology represents a breakthrough in powertrain development. The QX50, powered by the VC-Turbo, is the first production vehicle ever to give drivers an engine that transforms on demand, setting a new benchmark for powertrain capability and refinement. This unusually smooth engine offers customers power and performance, as well as efficiency and economy.

Boost pressure is controlled by an electronically controlled valve (wastegate), which precisely controls the flow of exhaust gases passing through the turbine. This ensures high power and efficiency and helps reduce emissions.

Thanks to the variable compression ratio system, the perfectly balanced VC-Turbo engine does without balance shafts typically required on four-cylinder engines. The VC-Turbo operates smoother than its conventional in-line counterparts, with noise and vibration levels comparable to those of a traditional V6. This became possible, among other things, thanks to the arrangement with additional rocker arms, in which the connecting rods are almost vertical during the working stroke of the pistons (unlike the traditional crank mechanism, where they move from side to side). The result is an ideal reciprocating motion that does not require balance shafts. That's why, despite the use of a variable compression ratio system, the VC-Turbo engine is as compact as a traditional 2-liter four-cylinder engine.

It should be especially noted and extremely low level vibrations of the new engine. In factory testing, during which INFINITI experts compared the performance of the VC-Turbo with competing four-cylinder engines, the revolutionary engine demonstrated significantly lower noise levels - almost like 6-cylinder units.

This is also due to the “mirror” coating used by INFINITI on the cylinder walls - it reduces friction by 44%, allowing the engine to run smoother. The coating is applied by plasma spraying, then hardened and honed to create an ultra-smooth surface.

The new INFINITI QX50 with a 2.0-liter VC-Turbo engine is the world's first car equipped with the Active Torque Rod (ATR) system. New QX50 – the only car in a classroom equipped with similar technology. Integrated into upper support engine, through which most of the noise and vibrations are usually transmitted to the body, the ATR is equipped with an acceleration sensor that records vibrations. The system generates reciprocating vibrations in antiphase, allowing the four-cylinder unit to remain as quiet and smooth as V6 engines, and reduces engine noise by 9 dB compared to the previous QX50. As a result, the VC-Turbo is one of the quietest and most balanced engines in the premium SUV segment.

INFINITI installed the world's first active mounts on a diesel engine back in 1998, confirming the brand's innovation in the field of powertrains. INFINITI engineers developed the ATR system from 2009 to 2017, paying special attention to reducing size and weight - in the first prototypes, the dimensions of the vibration motor were considered the main problem. However, the development of more compact reciprocating actuators has made it possible to install the ATR in a smaller housing, while fully maintaining the system's ability to absorb vibration as effectively as possible.