One of the most important questions that any owner of this equipment faces. Sometimes the manufacturer clearly states fuel consumption per unit of power ( horsepower or kilowatts) in grams. You can find this information in the loader specification table. 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, at maximum 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 a 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.
Not run-in equipment 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 power unit there is a lower load than during the test tests. 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.
Calculation of fuel consumption rates per hour, shift, per month, etc.
O. Shevtsova
According to estimates, Russian market counterbalance forklift trucks with engine ratio internal combustion and electric is 68%:32%. The predominance of forklifts is explained by the fact that the processes of industrialization (development of industry and construction) in our country are still a greater incentive for the market of loading equipment than the development of warehouse logistics. That is, at present, the main consumers of loaders in Russia are enterprises and companies of various industries, and not logistics, although the latter is developing at a fairly rapid pace.
Play a certain role and features of the operation of equipment: work for a significant part of the year with low temperatures in open areas away from perfect condition coatings and so on. diesel engine requires less purchase, maintenance, operation costs - it is a reliable, easy to maintain, powerful and efficient source of energy. In addition, such machines are produced in a wide range of carrying capacity (up to 43 tons) and with a large assortment attachments to perform a variety of technological operations, and the exhaust gas cleaning system ( particulate filters) used in latest models leading manufacturers, reduces harmful emissions by 70...98%, which allows you to work indoors.
One of the characteristics of the "price of ownership" of a diesel forklift is fuel consumption. In the summary table of technical characteristics, the manufacturer often indicates the specific fuel consumption in grams per unit of power (hp or kW). Meanwhile, this parameter does not give an idea of how much it will "eat" in practice. this engine, how much fuel will be consumed per hour, shift, per month, etc. For this, special methods are used, one of which we will acquaint readers with.
How to calculate the fuel consumption rate
Suppose a forklift has already been purchased and put on the balance sheet of the enterprise. Accounting asks employees service center authorized dealer, calculated data for the write-off of fuel.
Those, in turn, determine the rate of fuel consumption by the formula
Q \u003d N q / (1000 R k 1),
Where Q– specific fuel consumption (data from the power characteristic curve);
N– power, h.p. (data with power characteristic curve);
R- density of diesel fuel (0.85 kg / dm 3);
k 1- coefficient characterizing percentage operating time at maximum engine speed.
Engine power and specific fuel consumption are taken from the engine maintenance manual, which uses official dealer performing service maintenance. The data is entered into it in the form of a specific fuel consumption curve, which is built by the engineers of the manufacturing plant based on the results of engine testing in various modes, including on maximum speed.
In practice, in order to achieve the maximum engine speed, we squeeze the accelerator pedal all the way, we sink it literally "to the floor". In this mode, the machine accelerates, drives uphill with a load, or lifts a load to its maximum height with maximum speed. It is clear that the loader does not work the entire shift, but only some part of it. Hence, it becomes necessary to apply the coefficient k1. In fact, the coefficient characterizing the work at maximum speed is an indicator of the specifics of the enterprise's technological cycle.
Let's consider two examples.
Example 1 With the round-the-clock work of the enterprise, the shipment of products actually takes place twice a day for 2 hours, that is, only 4 hours out of 24. During these "rush hours" the entire fleet of loaders is involved, all access roads are occupied, there is maximum number trucks. The rest of the working shift, loaders are operated with minimal or medium intensity.
Example 2 The rented loader works on unloading wagons and loading trucks almost non-stop for an 8-hour shift, but it does not overcome the slope, does not use the maximum height of the forks, since the serviced platforms are located at a level of 1.5 ... 2 m from the floor. The maximum engine speed is used in this case when the truck is accelerating, overcoming the distance between the loading and unloading zones, which is about a third of its working time.
As you can see, the coefficient characterizing the percentage ratio of the operating time with maximum and minimum load will be larger in the second case. For exact definition its value, it is necessary to measure the time when the loader lifts the maximum load, when it moves, overcoming resistance pavement(acceleration, driving down a slope, etc.). Summing up these time indicators, we get the operating time during which the engine experiences maximum loads, and subtract it from the total duration of the work shift. The ratio of the minimum load time (70%) to the maximum load time (30%) is the required ratio. So, if the time of work with the maximum load was 30% of the duration of the shift, the coefficient will be equal to 2.3(70%:30%)=2.3.
For example, for a 4D92E engine with a power of 33.8 hp. (Komatsu loader AX50 series) operating at maximum speed for 1/3 of the working time, the calculated figures according to the formula will be 3.49 l / motor-hour:
Q = 33.8 x 202/(1000 x 0.85 x 2.3) = 3.49 l/mo.h.
What's in practice?
Understandable and clear is such an indicator as the amount of fuel in liters consumed per hour of operation of equipment by operating enterprises and organizations. It should also be noted here that theoretical fuel consumption calculations for a loader will always be slightly higher than in practice, since in real conditions the load on the engine is less than in test conditions. Therefore, to determine the fuel consumption for write-off, it is necessary to carry out control measurements.
A kind of timekeeping was carried out for a diesel 3-ton Komatsu BX50 series (FD30T-16), operating from 12 to 21 hours, i.e. 9 hours daily. Technological operations: unloading trucks, moving goods into wagons. The fuel consumption reading for the engine on the FD30T-16 Komatsu 4D94LE loader was 2.5 l/h.
For a number of other companies, we have received the following data on the fuel consumption of a Komatsu loader:
- 1.7 l/h – loader with capacity (g/p) 1.5...1.8 t (engine 4D92E), shift 24 hours;
- 2.5 l/h – loader capacity 2...2.5 t (engine 4D94E), shift 24 hours;
- 2.2 l/h – loader capacity 1.5 t (engine 4D92E), shift 8 hours;
- 2.9...2.95 l/h – loader capacity 1.8 t (engine 4D92E), shift 8 hours or more.
Thus, the fuel consumption indicators are influenced by such parameters as the power and specific fuel consumption of the engine, the duration of the working time when it operates at maximum speed. Machines with high mileage or, on the contrary, new, but not yet run-in, show higher fuel consumption than those on which the engine is adjusted. Higher than normal fuel consumption is shown by machines during special testing when operating at full load (for example, at the manufacturer's declared average rate 3 l / h during the test, a 1.5-ton loader can show a flow rate of up to 5 ... 6 l / h).
What are vehicle manufacturers doing to reduce fuel consumption?
By the way, low fuel consumption is not an end in itself, it is important in combination with high performance, machine dynamics, i.e., when assessing how well and quickly the machine responds when performing work operations, how confidently it climbs, etc. What are manufacturers doing to increase the speed of technological operations, leaving fuel consumption at the same level? For example, machines are equipped with a hydraulic system high pressure, and this allows you to increase the lifting speed. True, by increasing the rate of transmission of dynamic impact, it is necessary to ensure the tightness of the circuit (high-pressure hoses, hoses, etc.) through the use of high-quality materials. In order for forklifts of one of the economy class brands to compete in this indicator with more expensive cars, the manufacturer will have to use a better transmitting device. Accordingly, this will lead to an increase in the cost of the car, and it will lose its main competitive advantage - affordability.
Another engineering technique is the division of the hydraulic flow into steering and on lifting equipment. In the latest series of Komatsu BX50 forklift trucks (capacity 2...3 t) hydraulic system super lift: twin pumps ensure that the steering and lifting mechanism operate independently of each other. The result is a steady rise in Idling at maximum load, low fuel consumption.
The new Still Gmbh RX70 diesel loader is equipped with a hybrid drive, consumes 2.5 liters of fuel per hour (measured on the basis of a model with a capacity of 2.5 tons according to the new VDI 2198 criteria, i.e. after 60 working cycles per hour). Hybrid drive technology involves the installation of a diesel or gas engine and electric motor. This loader model is used hydraulic pump, which supplies oil to the hydraulic system as needed, and not constantly, which also contributes to fuel economy.
The creators of Jungheinrich loaders of the DFG / TFG 316-320 series with a capacity of 1.6 ... 2 t, speaking about the advantages of the engine, emphasize that the used industrial engine large volume (2.5-liter diesel engine with a power of 28 kW) is already on low revs develops maximum torque, which also allows for low fuel consumption. For the Perkins 404C.22 engine of the DFG 16 As model, the manufacturer indicates a fuel consumption of 3.1 l / h according to the VDI cycle.
By adopting a high torque motor and steering system with hydrostatic transmission in diesel loader Linde H16D (VVV/ADG engine) provided fuel consumption of 2.3 l/h on the VDI cycle.
In a number of design developments of almost all leading manufacturers of loaders there are models designed to work on hydrogen fuel. It is clear that high-tech models cost 20 ... 30% more than basic ones. Nevertheless, serious attention is paid to this direction as a kind of intellectual contribution to the development of the brand.
One of the main questions forklift owners ask themselves is how to calculate fuel consumption. Of course, in the summary table of technical characteristics, the manufacturer indicates the fuel consumption per unit of measurement of power (kW or hp) in grams, but this does not give a clear idea of how much fuel is required in practice for operation.
How to calculate the fuel consumption rate of a forklift truck per hour?
The fuel consumption rate is determined by the following formula:
Q = Nq/(1000Rk1)
- q is the specific fuel consumption*,
- N - engine power, hp *,
- R is the density of diesel fuel (0.85 kg / dm 3),
- k1 - the ratio of the operating time at the rotational speed (maximum) of the crankshaft, expressed as a percentage.
* - data from the power characteristic curve is used
Specific fuel consumption and engine power can be found in the maintenance manual, which contains data in the form of a specific fuel consumption curve built by the manufacturer's specialists based on the results of engine tests in various modes.
In practice, the maximum engine speed is reached in a simple way: The accelerator pedal is depressed as far as it will go. And the loader accelerates, goes uphill with a load, lifts the load to the maximum height with the maximum speed. Of course, in this mode, the machine works only some part of the shift. This leads to the need to apply the coefficient k1, which characterizes the operation at maximum speed. This is a kind of individual indicator of the specifics of the workflow.
For example, a rented diesel forklift is used for loading trucks and unloading wagons for almost the entire 8-hour shift, but does not overcome slopes, and since the serviced platforms are not located above 1.5-2 meters from the floor, it does not need to use the maximum height fork lifting. The maximum engine speed of the power unit is used only when the truck is accelerating to overcome the distance between the unloading and loading areas. Approximately it takes one third of his working time.
But the situation may be somewhat different: with a 24-hour operation of the enterprise, the shipment of products takes place 2 times a day for 2 hours. The rest of the time, loaders are used with medium or minimal intensity. That is, the coefficient that characterizes the ratio of the operating time with the minimum and maximum load will be higher in the first case.
Its exact value is determined by measuring the time when the forklift lifts the load. maximum weight, overcomes the resistance of the road surface (moving on a slope, acceleration, etc.). When summing up these indicators, the operating time is obtained, during which the power unit of the machine is subjected to maximum loads. This time must be subtracted from the total duration of the work shift.
The required coefficient is the ratio of the operating time with the minimum (70%) and maximum load (30%). That is, if the machine was operated with a maximum load of 30%, then the coefficient is: 70%:30% = 2.3. Example: Komatsu AX50 forklift equipped with a 33.8 hp 4D92E engine. A third of the duration of the shift is operated at maximum speed.
Q \u003d 33.8 x 202 / (1000 x0.85 x2.3) \u003d 3.49 l / hour.
Forklift fuel consumption rate. Practical aspects
Practice is slightly different from theoretical calculations. Fuel consumption is influenced by the length of time the truck is running at maximum speed, specific fuel consumption and engine power. New technology, not run-in, or cars with high mileage show more consumption than those on which the engine has already been adjusted. Excessive fuel consumption will also be revealed during special testing when working with the maximum load: a 1.5-ton forklift can show a consumption of 5 ... 6 liters per hour (with an average rate of 3 liters per hour).
It is worth noting that the load on the engine in real conditions is less than under test conditions. To determine the fuel consumption for write-off, it is necessary to carry out control measurements.
Here is the timing for the Komatsu BX50 forklift. Working operations: moving goods into wagons, unloading trucks.
| Engine | load capacity | Working hours | Fuel consumption |
| FD30T-16 | 3 tons | 9 hour work day | 2.5 l/h |
| 4D92E | 1,5-1,8 | 24 hour shift | 1.7 l/h |
| 4D92E | 2-2,5 | 24 hour shift | 2.5 l/h |
| 4D92E | 1,5 | 8 hour work day | 2.2 l/h |
| 4D92E | 1,8 | 8 hour work day | 2.9-2.95 l/h |
Indications based on data from a number of Russian companies
Diesel Forklift Fuel Consumption Calculation
When buying a diesel forklift, the buyer may be interested in the fuel consumption consumed by the forklift. This is due to the fact that the loader must be put on balance, the fuel must be written off in accordance with the standards, and the cost of work and goods must be calculated. Manufacturers in technical specifications diesel forklifts indicate "specific fuel consumption", which is measured in grams per unit of power (hp or kW).
N - engine power;
Q - specific fuel consumption;
Q is the maximum theoretical fuel consumption in grams per 1 hour of engine operation at maximum power.
For example, if the following parameters were indicated in the technical characteristics of the loader:
Rated power of the engine, kW. (hp), not less than: 59 (80)
Specific fuel consumption g/kW. h (g/l.s.h) no more than: 265 (195)
That for 1 hour of work the loader would have spent 265 * 59 = 15635 grams of fuel.
When calculating actual fuel consumption, two corrections must be taken into account:
1. the loader engine does not run all the time at maximum speed with maximum power,
2. Fuel accounting is usually carried out in liters, not grams.
Therefore, to calculate real fuel consumption loader should use the improved formula:
Q = Nq/(1000*R*k1),
Q - specific fuel consumption;
N - power, hp (kW);
R is the density of diesel fuel (0.85 kg/dm3);
K1 - coefficient characterizing the percentage of the operating time at the maximum engine crankshaft speed;
Q - fuel consumption in liters per hour.
Since in practice the loader is not loaded to the maximum during the shift, the loader engine does not run at its maximum power all the time, and the power varies depending on the load. Hence, it becomes necessary to apply a coefficient that would take into account the ratio of the engine operating time at maximum speed to the engine operating time at minimum speed. If there is no reliable data on the operation of the loader, it is assumed that out of 100% of the working time, only 30% of the machine is working at maximum speed, therefore k1 will be equal to 70%:30% = 2.33.
An example of calculating fuel consumption in liters per hour for the D3900 engine.
Q=265 g/kWh;
R -0.85 kg/dm3;
Q \u003d N * q / (1000 * R * k1) \u003d 59 * 265: (1000 * 0.85 * 2.33) \u003d 7.9 l / hour.
In reality, theoretical calculations of diesel fuel consumption will always be slightly higher than in practice, since in real conditions the loader works less and the load on the engine is correspondingly less than in test conditions.
According to our statistics, the fuel consumption for the D3900 engine ranges from 4.5 l / h to 7.5 l / h, depending on the load.
The task of determining fuel consumption for trucks with internal combustion engines 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, efficiency value is also not a constant value, and 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 the reduced specific fuel consumption, i.e. fuel consumption per hour per 1 unit of generated output power. 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 of diesel fuel (summer) equal to 0.86 kg/l, the consumption per l/h can be recalculated:
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, at a lower 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 the JIS D6202 cycle (Japanese Industrial Standard).
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. Used in tests clean diesel fuel or gas (for MITSUBISHI used pure propane) that meets the standards specified in the Owner's Manual, may be very different 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 fuel efficiency information is limited to the above data for the D3900 engine.
For Mitsubishi loaders, the data is 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.
