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What causes diesel engine power shortage?
- Aug 28, 2017 -

Diesel engine after a long period of operation, due to parts wear or operation, improper adjustment, maintenance and other reasons are not timely, often there will be insufficient power problems. The main reasons are two aspects: First, due to bad combustion chamber, lack of fuel supply, fuel injector bad, lack of gas supply, oil timing adjustment and other reasons, resulting in incomplete combustion of fuel, resulting in diesel Lack of power; the second is due to mechanical wear is too large, poor lubrication, poor cooling, improper installation and other reasons, resulting in the friction of the diesel engine itself is too large, so that the output power reduction, resulting in diesel engine power shortage. Therefore, in the analysis of the exclusion of diesel engine power failure, the Star remind you to seize the burning and the quality of the friction loss of the two key issues, combined with the operation of the user parts of the diesel wear and technical status of the understanding and master , To find out the cause of diesel engine power shortage of the most likely reasons, and then check and exclude.


   1. Insufficient oil supply

   Insufficient fuel supply is one of the more common faults in the engine. There are two cases easily lead to lack of engine oil supply:

   The first case is the oil half of the lead caused by increased resistance to oil supply, so that poor oil supply machine. In this case, the machine in the small load power supply is normal, but in the heavy load power supply, due to poor fuel supply and the required increase in fuel supply, the engine will be a clear phenomenon: the speed down, the sound becomes " Harder ". At this point the need for fuel lines and diesel filters to check, remove the plug or replace the filter can be.

   The second case is the lack of low-pressure oil pipeline closed air, resulting in air resistance. This fault phenomenon is also more obvious: In addition to the lack of power, the tubing joints can hear the obvious "zi zi" sound, increase the throttle, this sound also increases. After the leak is found, re-tighten the joint screw or replace the gasket as the case may be.

      2. In and out of the exhaust system

     When the air intake system is blocked, it will lead to lack of diesel engine intake, power down, the sound boring, while exhaust smoke. The most common failure of the intake system is the air filter clogging. This fault phenomenon is more obvious, easy to judge, as long as careful cleaning air filter can be resolved. For the supercharged diesel engine, in addition to the air filter plug, into the exhaust system leak will lead to lack of machine power. Because the supercharged diesel engine is driven by the exhaust pressure turbine rotation, to the intake pipeline to transport compressed air, thereby increasing the engine power. Therefore, the intake and exhaust system of the supercharged diesel engine must be completely sealed. If the exhaust system is leaky, the exhaust pressure will be reduced, the turbocharger speed will decrease, the engine inlet pressure will be reduced, and the power will be reduced , Performance for lack of power. If the air intake system leaks, the same will be due to lack of intake caused by the machine power down. Intake and exhaust system leak check, available cotton, fine cloth and other close to the pipe joints, if there is a clear blow or suction into the seam phenomenon, then there is a leak, the need to install the pipe joints Gasket or tighten the screws.

   3. Piston group failure

     Piston group failure is mainly piston components wear and tear. When the piston, piston ring and cylinder wear, will cause poor cylinder compression, the engine power shortage. Phenomenon is working weak, exhausted blue smoke, consumption of oil. Serious wear and tear, but also accompanied by crankcase fan and engine abnormal sound.

Causes of severe wear and strain in the piston group:

First, the engine is not fully warmed up after the start, in the cold state suddenly accelerated or load.

   Second, the engine temperature is too high, resulting in excessive expansion of the piston group parts and hardness and strength decreased, so that serious mechanical wear or tear. After such a failure, the machine must be overhauled, replace the piston and cylinder, is strictly prohibited to continue to use the machine, or prone to serious accidents. In order to avoid serious wear and tear of the engine, usually in accordance with the procedures to operate the machine to ensure that the machine work in good condition.

The most important thing is to note the following three points:

1. After the start to fully warm and then speed, to avoid cold cold machine;

2. To keep the oil pressure in the specified range, not too large or too small;

3. Shut down before running idle for several minutes, so that the machine temperature drops and then stop, not in the high-speed operation suddenly shut down.

       4. Supercharger failure

   The supercharger is an important part of the supercharged engine, it must maintain a good working condition, especially the axial and radial clearance of the rotor must be kept within the specified range. If the supercharger failure, will cause the speed down, lower intake pressure, and ultimately lead to lack of engine power.

The main performance of the supercharger failure is as follows:

First, "eat oil".

   Second, there is scratched sound. The main cause of this phenomenon is the rotor shaft and bearing wear serious and seal ring damage, resulting in consumption of oil and sound. When the rotor shaft and bearing wear serious, affecting the normal work of the machine, you must replace the parts.

To avoid the supercharger accidental wear method is strictly in accordance with the operating procedures to use the equipment, the most important thing is to pay attention to two points:

   First, the engine just started, you must idle for 3 to 5 minutes, the oil has been formed in the lubrication system circulation, oil pressure rose to normal after the speed, plus load;

   Second, before the shutdown to idle about 3 minutes, until the engine and supercharger speed down after the shutdown. It is strictly prohibited after the sudden throttle, because this operation will make the oil pump to stop working and the supercharger is still high-speed rotation, so that the lack of oil turbines due to the formation of dry friction, aggravate wear and tear, serious damage to the turbine even , The rotor shaft is broken.

   5. Engine injection time are not allowed

     Different types of diesel engines have different requirements for fuel injection time, such as 4135 diesel fuel injection time for the top deadline 28 ° to 31 °. Improper fuel injection time will significantly reduce the engine power, and damage to the larger parts. Fuel injection is too early, the engine starts difficult, black smoke, work vibration increased, the sound becomes "irritable", a knock sound, machine temperature rise, the exhaust color is thicker than normal; The engine starts difficult and gray or white smoke, the work sounds boring, the machine turned weak, exhaust smoke black smoke, serious exhaust pipe blasting, exhaust pipe temperature increased significantly. Improper injection time is due to the machine for a long time vibration, so that the drive shaft and high-pressure pump camshaft joint loose, resulting in a certain angle caused by poor and found that fuel injection time is not, as long as the required data to re-adjust to the specified value, And tighten the screws.

   6. Three pieces of wear and tear

     The plunger, the oil valve and the needle valve are the three main parts of the diesel engine. They are the key components of the diesel engine. Any failure will affect the power output. When the plunger even wear, will make the high pressure is not established quickly, the oil pressure is too low, the oil supply is insufficient; out of the valve even wear, will cause the oil is not crisp, there are secondary fuel injection or drip phenomenon , The machine speed instability, vibration intensified, exhaust black smoke; needle valve wear, will produce drip phenomenon, so that the nozzle nozzle, a serious impact on the fuel injection quality, resulting in diesel fog bad, exhaust Black smoke. Three final damage to the final result, are the impact of the engine power output, the machine performance for the lack of power. Even after the damage can not repair, only the overall replacement. The cause of the damage, in addition to the normal use of the wear and tear, but also with the quality of the fuel, as well as the user's methods of operation are closely related. Therefore, in addition to the use of qualified quality fuel, but also according to the correct operation of the use of equipment. Such as try to avoid fierce acceleration; long-term parking and then re-enable, to carefully check the state of the machine, in particular, to check the flexibility of the plunger; regularly check the injector fuel injection pressure and remove coke and so on.