The reasons for the large fuel consumption can be found from the following aspects: first, the relevant parameters of the injection pump are improperly adjusted, the second is the engine working condition is poor, the third is the car's walking device is poor, and the fourth is the driver's own driving operation is not correct.

When driving, if the engine power is still good, only the fuel consumption is too large, which is mostly caused by the adjustment of the oil supply of the injection pump (some are caused by the loosening of the oil supply limit screw). Some drivers believe that the more the fuel supply is adjusted, the more powerful the car will be, but this view is wrong. The fuel injected into the cylinder must be mixed with the sufficient amount of air inhaled by the engine in order to obtain good combustion and achieve high efficiency energy conversion. If only the amount of fuel injection is increased, but the amount of air inhalation is limited by the engine structure and cannot be increased accordingly, then the oxygen in the air with the combustion-supporting effect must not be used enough, and the fuel can not be fully burned. As a result, a large number of incomplete combustion exhaust gas into billowing smoke from the exhaust pipe out of the car, wasting fuel and polluting the environment.

If the driver feels that the engine is insufficient, and the fuel consumption is still too large, this is the same reason for the large fuel consumption and weakness. Because of the lack of power, the climbing ability is reduced, and when climbing, we have to change the slow gear to drive at a speed lower than the economic speed. It is also because of the lack of power, acceleration is very fast, the driver can not make full use of the inertia of the vehicle to save fuel, and often have to step on the accelerator to a large. Therefore, to save fuel, it is necessary to make the car in good condition, and it is not good to carry out maintenance and repair in time.

In addition to the performance of the engine itself, whether the car's walking device is good is also important. The output power of the engine is transmitted to the wheel in many links, if the transmission efficiency is reduced due to the serious grinding or improper adjustment of that link, the fuel consumption will increase. The way to judge whether the walking device is good is to see whether the medium speed or acceleration state of the car is normal and whether the vehicle can fully glide under the premise of ensuring the safety and effectiveness of the braking.

Between the driver, the car and the road, the driver is the subject. If the driver cannot closely cooperate with the car and the operating conditions, and cannot timely choose the correct driving operation according to the changes in the operating conditions, the fuel consumption will increase. Compared with drivers with different technical levels driving the same car on the same road, the fuel consumption difference can be up to 20 ~ 25%, which shows the important significance of correct driving operation on fuel saving.

From the standpoint of fuel saving, driving operations should mainly pay attention to the following points:

(1) Master economic speed driving. There is a small fuel consumption speed in the car, called economic speed, high, lower than this speed will increase fuel consumption. Generally, the economic speed of trucks in high-speed gear and flat roads is 30 ~ 50 km/h.

(2) Under the premise of ensuring safety, try to use the car to slip inertia to achieve the purpose of fuel saving. In the field of vision, the road is flat and the traffic situation is not complicated, adopt the mode of accelerating and coasting alternately; In hilly areas, the mode of accelerating slope and sliding downhill is used alternately. When the parking place can be reserved, the gear can be removed in advance, and the brake can be replaced by the slide.

(3) Control the cooling water temperature of the engine. Generally, the water temperature is controlled at about 90 ° C, which is too high or too low will reduce the engine performance and shorten the service life of the engine. The greater impact on fuel consumption is the low water temperature, because the cooling water temperature is low, the engine is too cold, a large amount of heat energy is taken away by the cooling water and cooling air, and the thermal efficiency will be reduced. In general, for every 10 ° C decrease in water temperature, fuel consumption will increase by 2.5%.

In addition, the number of starts, rapid acceleration, braking and driver judgment will also increase fuel consumption to varying degrees.