Calculation of fuel consumption rates per hour, shift, per month, etc.
O. Shevtsova
The Russian counterbalanced forklift market is estimated to have a 68%:32% ratio of internal combustion and electric drive vehicles. 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.
The peculiarities of equipment operation also play a certain role: work for a significant part of the year at low temperatures in open areas, far from the ideal state of the coating, and so on. The diesel engine is less expensive to buy, maintain, operate - it is a reliable, easy to maintain, powerful and efficient source of energy. In addition, such machines are produced in a wide range of payloads (up to 43 tons) and with a wide range of attachments to perform a variety of technological operations, and the exhaust gas purification system (particulate filters) used in the latest models of 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 this engine will “eat up” in practice, how much fuel will be consumed per hour, shift, per month, etc. For this, special techniques are used, one of which we will introduce readers.
How to calculate the fuel consumption rate
Suppose a forklift has already been purchased and put on the balance sheet of the enterprise. The accounting department requests from the employees of the service center of the official dealer the calculated data for the write-off of fuel.
Those, in turn, determine the rate of fuel consumption by the formula
Q = Nq / (1000 Rk1),
where Q is the specific fuel consumption (data from the power characteristic curve);
N - power, hp (data with power characteristic curve);
R is the density of diesel fuel (0.85 kg/dm3);
k1 is a coefficient characterizing the percentage of the operating time at the maximum engine crankshaft speed.
Engine power and specific fuel consumption are taken from the engine maintenance manual used by the authorized service dealer. The data is entered into it in the form of a curve of specific fuel consumption, which is built by the engineers of the manufacturing plant based on the results of testing the engine in various modes, including at 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 at 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 operation 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 “peak hours”, the entire fleet of loaders is involved, all access roads are occupied, and the maximum number of trucks is under loading. The rest of the working shift, loaders are operated with minimal or medium intensity.
Example 2. A 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 fork lift height, 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. To accurately determine its value, it is necessary to measure the time when the loader lifts the maximum load, when it moves, overcoming the resistance of the road surface (acceleration, movement on 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.
Loader fuel consumption rates. How to calculate correctly?
05.08.2019
Forklifts are widely used in various industries and households. Russian enterprises use both electric models and samples with an internal combustion engine. The second are more common.
Fuel costs make up the predominant part of expenditure items and have a direct impact on the cost of work and products. Therefore, before everyone who has forklifts with internal combustion engines in the park, an important question arises - how to correctly calculate the consumption of diesel fuel for a car. Forklifts are widely used in various industries and households. Russian enterprises use both electric models and samples with an internal combustion engine. The second are more common.
Traditionally, manufacturers of this type of equipment prescribe fuel consumption in grams per unit of power (kW or hp) in the summary table of those. characteristics. However, these data do not allow us to calculate the exact amount of fuel required to perform working manipulations, since there is no clear standard for this type of equipment with a mileage of 100 km, like for cars.
So, in order to calculate the rate of fuel consumption required for one motor-hour, the formula is derived:
In this case, q means specific fuel consumption*, N
- motor power in hp
*, under R
- fuel density, which is 0.85 kg / dm3, under
k1
- the ratio of the period of operation at the maximum crankshaft speed in percent.
* means that information from the power curve is involved here.
The specific fuel consumption and engine power are indicated in the maintenance manual compiled by the manufacturer's experts based on the results carried out in different modes of test tests of the power plant.
It is important to understand that the loader is distinguished by a significant number of loads in terms of intensity and type, which change during operation in the most unexpected way. In addition, the task is complicated by the fact that the predominant part of the operating cycle, the efficiency of the power plant is reduced due to operation at low speeds, due to which the efficiency cannot be attributed to a constant value, and fuel consumption does not correlate with power.
It is also worth noting that a number of features affect the volume of fuel consumption, including the quality of the fuel itself and lubricants, the adjustment and condition of the power plant, as well as operating conditions.
Based on the foregoing, when calculating fuel consumption, you need to understand that by simply multiplying the values \u200b\u200bspecified in the technical specifications by the shift time, we will get a result that does not correlate with the real one.
So, the maximum engine speed is achieved by pressing the accelerator pedal all the way, after which the car accelerates, overcomes the rise in the loaded state and lifts the load as high as possible without slowing down. Of course, the equipment operates in this mode only for a certain part of the shift, which is why the coefficient k1 is used, which means operation at maximum speed and serves as a kind of indicator of the specifics of the process.
Let's consider situations on concrete examples.
To begin with, let's take a diesel loader involved in loading trucks and unloading wagons on flat surfaces without slopes during an eight-hour shift.
In our case, the working areas are located no more than 1.5-2 meters from the floor level, so that the machine does not need to raise the forks to the maximum allowable height. The maximum engine speed is needed only when driving from the unloading area to the loading point, which takes up approximately one third of the total working time.
However, such a situation is also possible when, when the organization works around the clock, the equipment is involved in the shipment of goods twice within two hours, and the rest of the time it is operated in medium or minimum load modes. In this scenario, the ratio of the period of work will be greater in the first situation considered.
To determine the exact value of this coefficient, the time is measured when the machine is involved in lifting the most heavy loads, moves along inclined surfaces, and accelerates. Adding the obtained indicators, we get the period when the maximum load on the motor is reached, which is then subtracted from the entire duration of the shift.
The result should be the following coefficient: the ratio of the period of operation with a minimum (70%) and maximum load (30%). So, if the machine worked with a maximum load of 30%, then the coefficient is equal to 70%:30% = 2,3
However, as we noted above, practice differs from theory. So, fuel consumption indicators directly depend on the duration of the operation of the equipment at maximum speed, specific fuel consumption and the performance of the power plant.
We add that if an unrun-in loader or a model with high mileage is considered, the consumption will be greater than that of samples with an adjusted motor. In addition, fuel costs will be higher during the test, when the equipment will be operated at full load.
So, a car weighing 1.5 tons is able to demonstrate a fuel consumption of 5 - 6 l / h, while the norm is 3 l / h.
At the same time, do not forget that when operating in a real working environment, the motor will be subject to less load than during tests.
In this case, control measurements will help calculate the fuel consumption for write-off. Useful stuff? Share with your friends
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 a carrying capacity (capacity) of 1.5 ... 1.8 tons (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. Cars with high mileage or, on the contrary, new ones, but not yet run-in, show higher fuel consumption than those on which the engine is tuned. Fuel consumption higher than usual is shown by cars during special testing when operating with maximum load (for example, at an average rate of 3 l / h declared by the manufacturer during the test, a 1.5-ton loader can show consumption up to 5 ... 6 l / h).
How much fuel does a diesel forklift eat?
The Russian counterbalanced forklift market is estimated to have a 68%:32% ratio of internal combustion and electric drive vehicles. 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.
The peculiarities of equipment operation also play a certain role: work for a significant part of the year at low temperatures in open areas, far from the ideal state of the coating, and so on. The diesel engine is less expensive to buy, maintain, operate - it is a reliable, easy to maintain, powerful and efficient source of energy. In addition, such machines are produced in a wide range of payloads (up to 43 tons) and with a wide range of attachments to perform a variety of technological operations, and the exhaust gas cleaning system (particulate filters) used in the latest models of 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 this engine will “eat up” in practice, how much fuel will be consumed per hour, shift, per month, etc. For this, special techniques are used, one of which we will introduce readers.
How to calculate the fuel consumption rate
Suppose a forklift has already been purchased and put on the balance sheet of the enterprise. The accounting department requests from the employees of the service center of the official dealer the calculated data for the write-off of fuel.
Those, in turn, determine the rate of fuel consumption by the formula:
Q is the specific fuel consumption (data from the power characteristic curve); N - power, hp (data with power characteristic curve); R is the density of diesel fuel (0.85 kg/dm3); K1 is a coefficient characterizing the percentage of the operating time at the maximum engine speed.
Engine power and specific fuel consumption are taken from the engine maintenance manual used by the authorized service dealer. The data is entered into it in the form of a curve of specific fuel consumption, which is built by the engineers of the manufacturing plant based on the results of testing the engine in various modes, including at maximum speed.
