FUEL CONSUMPTION OF CONSTRUCTION EQUIPMENT
Fuel plays a fundamental role within construction industry. Diesel is used as fuel in most of construction equipment operation. It contributes more then 30 % of operational costs of construction equipment, the fluctuation of the price of fuel and fuel consumption have a major impact on the profits of the company. Hence, implementation efficient fuel management program is must for reduction in operational cost of construction equipment.
To counterbalance this situation some companies are creating a surcharge to deal with the ups and downs of fuel pricing or estimating construction cost with higher diesel consumptions. However, this can be a risky decision because it will increase substantially construction costs.
Diesel is also the most highly influential item in the construction industry that affects all supplies, material and labor costs.
To stand in competitive market scenario, constant improvement in way of planning, execution and monitoring are increasing in intensity. On the other hand, this competition of business presents great opportunities and challenges for the capital-intensive industries like construction industry for innovative solution.
Construction industry is having no control in cost of diesel, but there is possibility of reducing in consumption of diesel. We need to look to innovative solutions, go back to basics and reinvent the way construction equipment is being maintained and operated.
We need to put extraordinary care in use to counterbalance these issues, we need to depl oy, monitor and improve skill maintenance and operational crew for construction equipment management. This will help in reduction in fuel consumption of construction equipment.
So, how this affect construction industry? Quite simply, Project cost + Profit = Market price However, under the present scenario where all are facing the domestic and global competition, the above definition does not hold good & simply got transformed into: Market prices - Project Cost = Profit Although both equations mathematically look to be the same, the difference is obvious as in the present scenario. The customer who has become quite demanding with respect to cost, quality & variety determines the market price.
The current economic environment automatically brings
tremendous pressure on optimizing the project cost for survival. Monitoring and control fuel consumption and skill up gradation of operative and project t eam is one of best solution. Project cost can by optimized by enhancement of effectiveness of operation and maintenance, productivity of manpower and equipment, technology, waste reduction and skill of employee. All these factors have major impact in diesel consumption of equipments. Principle of Operation of Diesel Engine: Diesel engine (compression ignition engine) is the internal combustion engine, and used widely as the power source of the construction equipment. In diesel engine, the air is entered in the cylinder, and it is compressed adiabatically to a high temperature at the cylinder. When the mists of the fuel are jetted i nto the high temperature cylinder, it combusts automatically and push the piston back down, causing the crankshaft to rotate, the engine obtains the output power, which power's vehicle's motion. It can get the higher efficiency by high
compression ratio and it can use light oil and heavy oil such as diesel as the fuel.
Diesel fuel contains more heat energy (BTUs or joules) and much less volatile. The diesel engine’s design, including its high compression ratio, is intended to extract the maximum amount of power from its fuel. Formula to Estimate Maximum Engine Fuel Consumption The fuel consumption rate for a piece of equipment depends on the engine size, load factor, the condition of the equipment, operator's habit, environmental conditions, and the basic design of equipment. Fuel
consumed
is
proportional
to
the
power
developed.
Power
developed
is
approximately proportional to the cube of the engine revolution. Hence fuel consumed is proportional to the cube of the engine revolution. To determine the hourly fuel cost, the total fuel cost is divided by the productive time of the equipment. If fuel consumption records are not available, the following formula can be used to estimate liters of fuel used per machine hour, LPH = (specific fuel consumption x KW) / Fuel Specific Weight * load factor
These formulas can be used, when the engine is making peak power, which usually is near wide-open throttle. Fuel consumption will be decreased at cruising speeds. Also, engines with electronically-managed fuel injection and direct injection will yield higher fuel efficiency. Where, LPH is the liters used per machine hour, Specific Fuel consumption (at rated power): 0.2259 kg/KWH, KW is the rated Kilowatt of equipment at governed engine rpm, Fuel Specific Weight is specific gravity of fuel (weight of fuel in kg/liter): 0.85 kg/litre. Load factor in percent (ratio of average load KW on engine to rated KW), and Example: Specific Fuel consumption (at rated power) is 225.9 g/KWh = K Equipment Output is 129.6KW @ 2200 rpm = KW According to the calculation = K*KW/KPL = 0.226 *129.6 / 0.85 = 34.45 LPH (at full rated output of engine and full l oad) If machine performs in 40 to 60% load as standard = 34.45 * 40% = 13.78 lts/ hr
Fuel consumption depends on following factors in construction equipment:
Engine size and engine type.
Drive type fitted with the engine
Equipment design and aerodynamics (wind drag)
Quality of fuel
Load factor
Operating RPM of engine of the equi pment,
Frequent stops, speed variations or otherwise poor operating habits,
Operator skill
Operating hours and working of engine.
Insufficient intake air and filtration of intake air of engine.
Calibration of engine fuel pump and injector
Compliance of recommended maintenance checklist
Gross vehicle weight
Ambient temperature, altitude, humidity,
Wind direction and velocity,
Terrain elevation changes etc,
Final gear ratio.
Wheel alignment and tire pressure.
Misadjusted or dragging brakes.
Fuel Saving Tips When operating heavy machinery, certain practices can help in reduction of fuel consumption and consequently reduction in operational costs.
Inspect air filters regularly
Inspect air filters every 50 hours to ensure maximum operating performance. If air filter becomes clogged with dirt, the engine cannot get the air it needs and does not operate efficiently. Some machines have air flow indicators that indicate change or clean of air fil ter.
Grease fittings properly
Lubricate of machine according to manufacturers recommendations. By keeping your machine properly lubricated, fuel efficiency is increased simply because the power needed to perform operations is reduced. The more mobility the components have, the less work the hydraulic system must perform.
Check tire pressure
Check tire air pressure before and after each use. If the tire pressure is low, fill the tires as soon as possible. Low air pressure can reduce the efficiency of machine and lower fuel efficiency.
Be alert for signs of a mechanical problem
When alert signs of a mechanical problem, such as excessive black smoke, urgent repair of is better decision. Mechanical problems, such as a bad fuel injector, can significantly reduce fuel efficiency. If your fuel injector is over fueli ng a cylinder, machine is wasting fuel.
Run engine at low RPM whenever possible
Begin by running at a low rpm during operation, then slowly raise the rpm until the engine does not strain. This level will be the most efficient and effective rpm for the job. When a job does not require maximum power, running the engine at a lower rpm can significantly reduce fuel consumption.
Service and repair equipment regularly
Service of equipment (oil and filter change, tune up, exhaust system, brakes, spark plugs, belts, hoses) as per manufacturer's guidelines is highly required. Maintain equipment in best shape. If repairs of equipment are done immediately then also fuel consumption will reduce and also prevent costly problems that could have been avoided in the future.
Avoid aggressive acceleration
Try to avoid aggressive acceleration, and speeding. Driving this way will reduce fuel consumption.
Avoid excessive idling
Don’t leave a machine idling. When any machine is not in use, the engine should always be off. Leaving a equipment running or idling can burn fuel without use.
Plan driving routes carefully
Obviously, the less driving required, the less fuel will be used. Factoring in travel aspects such as congestion, high-traffic times, and busy roads can help reduce travel time. It is best to avoid peak travel times such as rush hour, and fi nd roads that are less frequented. However, some vehicles, such as backhoes and cranes, may not legally be allowed to travel on certain roads, so it can be wise to research the local laws before heading out to the j ob site.
Buy a Fuel-efficient Vehicle
First things first, during purchase new or used construction equipment, examine of vehicle’s fuel-efficiency is required apart from other factor. Usually, vehicle with a manual transmission turns out a better option as it provides the drivers with smart fuel economy.
Minimize drag and reduce excessive weight
Driving with the windows open, using roof or rear mounted racks and carrying heavy loads increase vehicle drag. Additional weight decreases fuel efficiency. Clean equipment and remove unnecessary heavy items (i. e. sandbags).
Proper selection of fuel
Use a lighter weight multigrade oil i n the fall - A heavy oil decreases engine efficiency, which can increase operating costs and emissions. Select the proper fuel for your vehicle as ou tlined in the owner's manual. Avoid a higher-octane fuel; it is more harmful to the environment because they require more crude oil to produce than l ower octane fuels.
Operator experience, machine condition, job site conditions, all affect fuel consumption rate. Reduction in fuel consumption will help in reduction expensive vehicle repair and also helps reduce emissions into the environment apart from reduction in construction cost. Diesel consumption of different capacity engine at different load factor
Specific Fuel consumption
Diesel Consumption Ltr / Hr
Output at rated KW
Specific
(at rated
at RPM
Gravity
power )
@2200
of Fuel
LF
LF
LF
LF
=25 %
=50 %
=75 %
=100 %
0.2259
20
0.85
1.33
2.66
3.99
5.32
0.2259
40
0.85
2.66
5.32
7.97
10.63
0.2259
60
0.85
3.99
7.97
11.96
15.95
0.2259
80
0.85
5.32
10.63
15.95
21.26
0.2259
100
0.85
6.64
13.29
19.93
26.58
0.2259
120
0.85
7.97
15.95
23.92
31.89
0.2259
140
0.85
9.30
18.60
27.91
37.21
0.2259
160
0.85
10.63
21.26
31.89
42.52
0.2259
180
0.85
11.96
23.92
35.88
47.84
0.2259
200
0.85
13.29
26.58
39.86
53.15
0.2259
220
0.85
14.62
29.23
43.85
58.47
0.2259
240
0.85
15.95
31.89
47.84
63.78
0.2259
260
0.85
17.27
34.55
51.82
69.10
0.2259
280
0.85
18.60
37.21
55.81
74.41
0.2259
300
0.85
19.93
39.86
59.80
79.73
0.2259
320
0.85
21.26
42.52
63.78
85.04
0.2259
340
0.85
22.59
45.18
67.77
90.36
0.2259
360
0.85
23.92
47.84
71.76
95.68
0.2259
380
0.85
25.25
50.50
75.74
100.99
0.2259
400
0.85
26.58
53.15
79.73
106.31
0.2259
420
0.85
27.91
55.81
83.72
111.62
0.2259
440
0.85
29.23
58.47
87.70
116.94
0.2259
460
0.85
30.56
61.13
91.69
122.25
0.2259
480
0.85
31.89
63.78
95.68
127.57
0.2259
500
0.85
33.22
66.44
99.66
132.88
0.2259
520
0.85
34.55
69.10
103.65
138.20
0.2259
540
0.85
35.88
71.76
107.63
143.51
0.2259
560
0.85
37.21
74.41
111.62
148.83
0.2259
580
0.85
38.54
77.07
115.61
154.14
0.2259
600
0.85
39.86
79.73
119.59
159.46
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