The task of determining fuel consumption for loaders with engines internal combustion is not as simple as it might seem at first glance.
One of the problems is that it is difficult to clearly define some typical mode of operation of a loader that sets a certain load on the engine, since fuel consumption primarily depends on the required power at the engine output shaft.
Compared to a car, a forklift is characterized by a significantly greater variety of loads that change in an unpredictable way during operation. For a significant part of the working cycle, the loader engine runs at low speeds, at which its efficiency is sharply reduced.
Thus, the efficiency value is also not a constant value, and the fuel consumption is not directly proportional to the power consumed, which further complicates the task.
Moreover, fuel consumption also significantly depends on many additional factors, such as: fuel quality, quality lubricating oils, engine adjustment, degree of wear, weather etc.
Thus, it is necessary to realize that the simple multiplication of the reducible technical specifications values of fuel consumption for the duration of the work shift can give a result very far from the real one.
However, the numbers given in the specifications are intended to serve as a guide and may be helpful when comparing various machines, if you know the conditions under which they were obtained and correctly understand the meaning of these parameters.
So, for example, in the Operation Manual for the D3900 Engine, such a characteristic is given as given specific consumption fuel, i.e. fuel consumption per hour per 1 unit of output power generated. For various modifications engine, it varies from 231 to 265 g/kW. h. By multiplying this figure by the required power characteristic of a given mode of operation, one can roughly estimate the fuel consumption in relation to these operating conditions.
For example, if you set the average output power to about 30kW, the fuel consumption for the D3900K is approximately equal to:
30kw x 240g/kw. h = 7200 g/h = 7.2 kg/h
Taking into account the density diesel fuel(summer) equal to 0.86 kg / l, you can recalculate the consumption per l / h:
7.2kg/h: 0.86kg/l = 9.7l/h
It should be remembered that even such a calculation is quite approximate, since the given specific fuel consumption is determined for the rated load, and, as already mentioned, for less power engine efficiency decreases and the specific (per unit power) fuel consumption increases.
In addition, it is obvious that this approach allows us to somehow characterize the fuel efficiency of the engine, but not the loader. Therefore, in international practice, a different approach has been adopted to determine the fuel consumption of a loader.
The most common are the following two standards for determining this parameter: according to the VDI 2198 cycle ( European standard) and JIS D6202 (Japanese Industrial Standard) cycle.
The VDI cycle is defined as follows:
– The travel speed must be such that 40 cycles* are completed within 1 hour.
* - Note: according to another source of cycles, it should be 45.
JIS cycle conditions:
1. Loader with maximum load travels from point A and near point B turns 90º
2. Forklift drive distance equal to the length load, stops and, after bringing the mast to a vertical position, raises the load to a height of 2m, then lowers it.
3. Reversing loader turns to point C.
4. The truck drives straight ahead and makes a 90º turn near point D.
5. The loader travels a distance equal to the length of the load, stops and, after bringing the mast to a vertical position, raises the load to a height of 2m, then lowers it.
6. Reverse the loader back to point A.
7. The distance between points B and D is 30m.
8. Within an hour it is necessary to complete 45 cycles.
Thus, the JIS cycle is somewhat more intense than the VDI and therefore requires slightly more fuel consumption.
It should be borne in mind that fuel consumption is highly dependent on the purity and quality of the fuel used. The pure diesel fuel or gas used in the test (for MITSUBISHI pure propane was used), which meets the standards specified in the Owner's Manual, may differ greatly from the fuel actually available in our conditions.
In order to standardize the fuel consumption of a forklift, it is advisable to recommend that the user of the machine carry out tests with a duty cycle close to the average for these specific operating conditions.
When choosing a machine, it is enough to focus on the standard parameters given below, given in official documents.
Relatively Bulgarian loaders information on fuel efficiency limited to the above data regarding the D3900 engine.
By loaders Mitsubishi data are given according to the VDI standard.
Fuel Consumption for MITSUBISHI Forklifts
The independent company "TNO" measured the fuel consumption of the following loader models. The measurements were made according to the VDI 2198 cycle, which is the standard adopted by European manufacturers.
Gas
Model kg/h
FG15K 1.8
FG20K 2.1
FG30K 2.7
Petrol
Model l/h
FD15K 1.9
FD18K 2.3
FD20K 2.4
FD25K 2.6
FD30K 2.9
FD45 3.5
cycle conditions:
– Run distance from point A to point B = 30 m.
– The travel speed must be such that 40 cycles are completed within 1 hour.
– Rated load (70-80% of maximum).
– At points A and B, the load must be lifted to a height of 2000 mm.
* - Notes: 1) When testing loaders with engines running on liquefied gas, propane was used as fuel. 2) Tests in the 4.5t class were carried out on the previous model.
One of the most important questions that any owner of this equipment faces. Sometimes the manufacturer clearly indicates fuel consumption per unit of power (horsepower or kilowatts) in grams. You can find this information in the table. specifications loader. However, for all its usefulness, it does not give a clear idea of how much fuel is required for work.
How to determine the consumption rate for 1 hour?
It is calculated as follows:
Q = Nq/(1000Rk1) , where:
- N is the power of the power unit;
- q - indicator of specific fuel consumption by the loader;
- R is the density of the fuel (diesel). Usually taken at the level of 0.85 kg/dm3;
- k1 - expressed as a percentage of the ratio of the operating time at the maximum crankshaft speed.
The power of the power unit, as well as the specific fuel consumption, can be found in the instructions for maintenance. The data is entered in the form of a graph. It is built by specialists of the manufacturing plant. The basis for this is the results of tests in different modes. In practice, the maximum speed of the power unit is very easy to achieve - squeeze the gas pedal all the way. As a result, the loader accelerates, overcomes the rise with the load, lifts it to the maximum allowable height and all this, mind you, top speed. Of course, in this mode, the loader will work only part of the shift. Therefore, it is necessary to use a coefficient designated as k1: it characterizes the operation at maximum speed. It can be called an individual indicator of the specifics of the loader.
Calculation example
Suppose that a diesel forklift was rented to load trucks and unload wagons. It works completely for the entire shift (8 hours), without overcoming slopes and without using maximum height lifting forks, since the platforms it serves are located at a height of only 1,500-2,000 mm. The maximum engine speed is only used when the engine is accelerating to cover the distance between the loading and unloading area. This operation takes approximately 30% of the working time.
But maybe so. The company operates 24 hours a day. But the shipment of materials (products) during this time is performed only 2 times for 2 hours. The rest of the time the loader is operated with minimum or medium intensity.
Accordingly, the coefficient characterizing the ratio of the operating time with the load (maximum/minimum) is lower in the second case. You can accurately determine its value by measuring the time during which the loader overcomes the resistance of the pavement (road) and lifts loads maximum weight. Summing up the indicators, we get the operating time, during which the maximum loads act on the unit. And it is this time that needs to be subtracted from the duration of the (total) one shift.
The desired coefficient is the ratio of the operating time with the minimum and maximum load(70% and 30% respectively). Therefore, if the loader was used with a maximum load of 30%, then the value of the coefficient is found by dividing 70% by 30% (that is, the value is 2.3).
For example, famous model loader AX50 from Komatsu is equipped with power unit 4D92E. Its power is 33.8 liters. with. In the event that 30% of the entire working shift is operated at maximum speed, then fuel consumption per 1 hour will be: 33.8x202 / (1000x0.85x2.3) = 3.49 liters.
About the practical aspects of the fuel consumption rate
Of course, there are certain differences between theory and practice. Fuel consumption is affected not only by the length of time at maximum speed, but also by the power of the power unit and specific fuel consumption.
Equipment that has not been run-in and loaders with impressive mileage demonstrate more high flow fuel than those whose engine has been adjusted. Excessive consumption can also be detected during special testing in case of operation with maximum load. For example, a one and a half ton car can show a consumption of 5 to 6 liters per hour, although average value this indicator - 3 liters per hour.
It should also be noted that in real conditions, a lower load acts on the power unit than during test trials. To determine the fuel consumption for write-off, you need to conduct a series of control measurements.
As an example, consider timing forklift BX50 from Komatsu (power unit - FD30T-16, load capacity - 3,000 kilograms). Type of work operations - unloading trucks, as well as placing goods in wagons. The work is done for 9 hours every day. Fuel consumption - 2.5 liters per hour of work.
With the 4D92E power unit, with a shift duration of 24 hours, the fuel consumption of the equipment is:
- for loaders with a carrying capacity from 1,500 to 1,800 kilograms - 1.7 liters per hour;
- for loaders with a carrying capacity from 2,000 to 2,500 kilograms - 2.5 liters per hour.
With an eight-hour shift, the consumption of a loader with a carrying capacity 1,500 kilograms equals 2.2 liters, and the carrying capacity 1,800 kilograms - up to 2.95 liters per hour.
Among all types of warehouse transport most in demand at Russian companies use diesel. This trend is not accidental - a diesel engine has high power, suitable for heavy vehicles with a carrying capacity of more than 40 tons, maintains performance in cold weather. In addition, motors from leading manufacturers effectively clean traffic fumes, so the equipment can be operated inside warehouse terminals.
Often the choice in favor of loaders powered by diesel fuel is explained by economic benefits - diesel vehicles are cheaper than gasoline and electric counterparts, have relatively low cost possession. The most important characteristic"price of ownership" is fuel consumption - low consumption of diesel fuel significantly reduces the overall costs of the production process. This indicator is calculated by the manufacturer and indicated in the table of technical characteristics as specific fuel consumption. True, the calculated data obtained during the tests may differ from practical indicators, because the loaders are operated in different conditions. To obtain real numbers fuel consumption for any settlement period (shift, month, quarter, year), it is necessary to use a special methodology.
Normalized fuel consumption of a forklift: mathematical calculation
After putting the equipment on the balance sheet of the accounting enterprise, the calculated data will be needed to write off the fuel. You can get this data using the formula:
Q = Nq/(1000Rk 1), where:
Q - standard fuel consumption in liters per hour;
N - engine power in horsepower;
q - specific fuel consumption from manufacturer's calculations;
R - the value of the density of diesel fuel (0.85 kg / dm3),
k 1 - the ratio of the periods of operation of the motor in normal and maximum modes.
The coefficient k 1 is a specific indicator of the work process. In reality, the loader engine runs on maximum speed only part of the shift: during the acceleration of the machine, driving at top speed, overcoming slopes with a load, lifting loads to the maximum possible height.
For example, if during a shift a technician works 60% of the time in normal mode and 40% with full load, then k 1 = 1.5 (60/40). Having calculated this indicator, it will not be difficult to determine the rate of fuel consumption. Let's take BULL FD35 with a load capacity of 3.5 tons with Japanese motor ISUZUC240 with a capacity of 35.4 liters. with. and specific fuel consumption of 202 g/kW*h, which is operated at maximum loads for a quarter of the shift. We get: Q \u003d 35.4 * 202 / (1000 * 0.85 * 1.5) \u003d 5.6 l / hour.
It should be noted that theory and practice may differ. For machines without running-in or with high mileage fuel consumption increases in comparison with the calculated indicators. In addition, the consumption of diesel fuel increases if the equipment is operated in the mode ultimate loads.
Fuel-optimized diesel forklifts: solutions from manufacturers
The main parameters that affect the fuel consumption of a forklift are engine power, specific fuel consumption and actual loads during the shift. That is, it is possible to determine the approximate costs at the stage of choosing a technique.
By the way, when buying a forklift, it is important to consider not only its efficiency, but also its performance. The task of the buyer is to choose equipment that quickly and accurately handles cargo without unnecessary fuel costs. These requirements are met by loaders with advanced hydraulics. For example, if there is hydraulic system high pressure the technique has an increased speed of lifting / lowering loaded forks. If the hydraulics are equipped with twin pumps, lifting equipment and steering machines operate independently of each other. Also an effective engineering solution is a hydraulic pump with periodic oil supply to the hydraulic system.
Leading forklift manufacturers innovate with every generation of forklift trucks, improving performance characteristics its products. Recently, China has been successfully competing with recognized world leaders. For example, in terms of fuel consumption and performance, Chinese Bull forklifts manufactured at the factories of the reputable Heli concern are comparable to European, American and Japanese classmates. At the same time, cars are much cheaper, which attracts Russian consumers.
Diesel forklifts are the most popular type of warehouse equipment among Russian buyers. This is easily explained. Diesel engines start easily with sub-zero temperatures, differ in power and are suitable for equipment with a carrying capacity of over 4 thousand kg. Market leaders implement in their equipment innovative technologies cleaning from exhaust gases. This allows them to be used diesel forklifts including indoors.
Another argument in favor diesel technology- economy. It is significantly cheaper than forklifts gasoline engine and warehouse electrical equipment and has a low cost of ownership. Diesel forklifts owe a lot to the latest low flow fuel. The manufacturer calculates this parameter and indicates it in the documentation attached to the equipment as specific fuel consumption. Of course, these are average data, and they may differ from the actual fuel consumption - after all, the operating conditions of the equipment are different. A special technique helps to calculate an objective indicator of fuel consumption for a certain period (work shift, month, quarter, etc.).
How is the normalized fuel consumption of a forklift calculated?
The formula below is used by the company's accountants to obtain the data necessary to write off fuel when the equipment is listed on the organization's balance sheet.
Q = Nq/ (1000Rk 1), where:
Q - standard fuel consumption (calculated in liters per hour).
N - engine power in l. with.
q - specific fuel consumption (according to the manufacturer);
R - the value of the density of diesel fuel (0.85 kg / dm3),
k 1 - the ratio of the periods of operation of the motor in standard and maximum modes.
The coefficient k 1 is a specific indicator of the work process. In practice, the forklift motor operates at maximum speed only part of the work shift: when accelerating, driving at maximum speed, lifting loads to maximum height, driving up a slope with a load. Let's assume that 60 percent of the shift time is for a truck operating in standard mode. 40 percent - with the maximum load. In this case, the coefficient k 1 is calculated as the ratio of the first indicator to the second: 60/40=1.5. After that, it is already easy to calculate the rate of fuel consumption.
Consider the calculation method on the example of the Chinese BULLFD35 forklift. Its load capacity is 3500 kg. The loader is equipped Japanese engine ISUZUC240 with a capacity of 35.4 liters. with. The specific fuel consumption declared by the manufacturer is 202 g/kWh. 25 percent of the working time the engine runs at maximum speed. Real indicator fuel consumption is calculated as follows:
Q \u003d 35.4 * 202 / (1000 * 0.85 * 1.5) \u003d 5.6 l / hour.
However, the calculated data may not match the actual data. For loaders without return or after long-term operation in practice, fuel consumption will be higher. The consumption of diesel fuel also increases during the operation of warehouse equipment in emergency mode.
How manufacturers optimize the consumption of diesel fuel by loaders
So, the consumption of diesel fuel is primarily affected by engine power, specific indicator declared by the manufacturer, and the intensity of operation of the loader during the shift. Therefore, the buyer can roughly calculate this parameter already at the stage of purchasing equipment.
Of course, the choice is determined not only by the efficiency of the model, but also by its performance. The ultimate goal of purchasing a loader is the organization of prompt and accurate loading and unloading operations with minimal financial costs. Loaders with an updated hydraulic system help in solving this problem. So, high-pressure hydraulics increase the speed of movement of the forks with a load. The dual pump hydraulic system allows independent operation of the lifting mechanism and steering of the loader. Another progressive technology is a hydraulic pump with periodic oil supply to the system.
The world's largest manufacturers of warehouse equipment update each generation of their products, improving their performance with the help of advanced engineering solutions. AT last years China is actively gaining positions in the world market warehouse equipment. For example, Chinese diesel loaders manufactured by BULL famous company Heli, in terms of fuel consumption and productivity, confidently compete with Japanese, European and American counterparts. At the same time, their cost is much lower, which, of course, adds points to them in the eyes of Russian consumers.
As the statistics show, Russian market Forklifts are dominated by internal combustion engine models, which are largely superior to those powered by electricity. This technique is used in harsh conditions requiring great resources. That is why one of the most important parameters The thing to pay attention to is the fuel consumption of the forklift.
Directly, the cost of goods and work performed is calculated on the basis of the used fuel and lubricants. The problem is that the fuel consumption of front loaders is much more difficult to determine than for a conventional one. vehicle, because for this technique the norm is not defined for a run of 100 km.
Key Features
Fuel consumption, which in most cases is indicated by manufacturers, is as follows: number of grams / unit of power. That is why there is a rather strong discrepancy in the numbers, which makes even more confusion not only for the average layman, but also for experienced drivers.
Specified by the company that produces the equipment, the fuel consumption does not give absolutely no understanding of how much this or that engine will actually consume. It is not clear what the norm will be for an hour, a work shift or a whole month of operation. AT this case, without the use of certain theoretical knowledge and calculation is indispensable.
How to calculate the fuel consumption rate
The fuel consumption rate for forklifts is determined by the following formula:
Q = (N*q)/(1000*R*k), where
N is an indicator of the power of specific diesel engines which is installed in specific model for which the calculation is performed.
q - nominal fuel consumption, which is prescribed in the relevant documentation for the engine.
R is an indicator of the density of the diesel fuel used. This parameter is known initially, according to the approved standard (840 kg / m 3 - for winter and 860 kg / m 3 - for summer). For convenience, a general indicator is set - 0.85 kg / dm 3.
k is a specific coefficient that reflects the time span in percentage, when front loader operated in normal mode and the amount of time it was used at maximum crankshaft speed.
Practical nuances
From the above information, we can see that almost all parameters in determining the fuel consumption of a forklift are known in advance, which cannot be said about the last coefficient (k).
To understand the situation, consider two examples:
- The equipment works at the railway station, loading and unloading railway wagons. The shift is about 8 hours without a break. Workers are located on a platform that is located higher than the level of location of special equipment, so the front loader forks do not rise to the height of the maximum reach of the boom. Limit rotation crankshaft the engine only occurs when the operator depresses the pedal to the stop, overcoming the distance between two certain points.
- The warehouse is open 24 hours a day. During the whole working day, there are two arrivals of trucks, which are unloaded in a few hours using the available equipment. It is at these moments that peak engine loads occur, but the rest of the time the crankshaft speed decreases, because the units perform warehouse work inside the warehouse without excessive intensity.
If we compare these two situations, then in the first case, the coefficient will be higher. This parameter takes into account peak loads - this is acceleration, movement downhill and lifting the load, during which the greatest use of equipment resources occurs. The calculation of fuel consumption for a front loader is determined based on the duration of its operation at peak crankshaft revolutions from the total operating time (shift).
Specific examples
In order to have a rough idea of all the nuances of the calculation, we determine the fuel consumption for Chinese forklifts. All information is taken from data provided by the manufacturer and technical parameters so there is no reason not to trust her. As for the coefficient (k), then by default we will take the indicator 2.3, based on the fact that the equipment operates at maximum speed of about 30% of the entire operating time.
To begin with, let's determine the fuel consumption for the Chinese SDLG LG936 loader with an engine power of 125 hp. with. The parameter specified by the manufacturer is 220 g/kW*h. According to the formula, the norm will be as follows:
(125 * 220) / (1000 * 0.85 * 2.3) = 14 liters.
Now let's determine the fuel consumption for the XCMG ZL50G loader. The power of its engine is 215 hp. with. Fuel consumption - 240 g / kWh. We believe:
(215 * 240) / (1000 * 0.85 * 2.3) = 26 liters.
From these data, it becomes clear that more powerful engine, the higher the fuel consumption rate per loader. Of course, real practice may differ significantly from the above theoretical calculations, because the specifics of the operation of Chinese loaders and other equipment may be different. The shift may be longer, the platform may be higher or lower, etc.
Other important nuance is the fact that a recently purchased unit that has not yet been properly run-in, like one that has a decent mileage - they are all characterized increased consumption fuel. In this case, it is necessary to carry out computational activities over several days of operation.
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