27

2023

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07

How to identify the true and false of diesel generator sets

Author:


Diesel generator set is a kind of power equipment that uses diesel engine as the prime mover and drives synchronous generator to generate electricity. This is a power generation device with quick start, convenient operation and maintenance, low investment and strong adaptability to the environment. Nowadays, generators are more and more widely used, so various faults will definitely be encountered in the process of use and operation. Here are 11 wrong operation methods of diesel generators:

(1) Running under load without warming up after cold start

When the diesel engine is started from a cold engine, due to the high viscosity and poor fluidity of the oil, the oil supply of the oil pump is insufficient, and the friction surface of the machine is poorly lubricated due to lack of oil, resulting in rapid wear, and even failures such as cylinder pulling and tile burning. Therefore, after the diesel engine is cooled and started, it should run at idle speed and heat up, and then run with load when the temperature of the standby oil reaches 40°C or above; the machine should be in low gear at the start, and drive in each gear for a certain distance until the oil temperature is normal and the fuel supply is sufficient After that, it can turn to normal driving.

(2) The diesel engine runs when the engine oil is insufficient

At this time, due to insufficient oil supply, the oil supply to the surfaces of each friction pair will be insufficient, resulting in abnormal wear or burns. For this reason, before starting the machine and during the operation of the diesel engine, it is necessary to ensure that the engine oil is sufficient to prevent cylinder scuffing and tile burning failures caused by lack of oil.

(3) Emergency stop with load or stop immediately after unloading the load suddenly

After the diesel engine is turned off, the cooling system water circulation stops, the heat dissipation capacity decreases sharply, and the heated parts lose cooling, which may easily cause the cylinder head, cylinder liner, cylinder block and other parts to overheat, cause cracks, or cause the piston to over-expand and get stuck in the cylinder liner. On the other hand, if the diesel engine is stopped without idling to cool down, the friction surface will not contain enough oil, and when the diesel engine is started again, it will aggravate the wear due to poor lubrication. Therefore, before the diesel engine is turned off, the load should be unloaded, and the speed should be gradually reduced to run for a few minutes without load.

(4) After the diesel engine is cold started, hit the throttle violently

If the throttle is slammed, the speed of the diesel engine will increase sharply, which will cause some friction surfaces on the machine to be severely worn due to dry friction. In addition, when the throttle is hit, the piston, connecting rod and crankshaft will undergo a large change in force, which will cause severe impact and easily damage the machine parts.

(5) Running when the cooling water is insufficient or the temperature of cooling water and engine oil is too high

柴油机冷却水量不足会降低其冷却效果,柴油机因得不到有效的冷却而过热;冷却水、机油的油温过高,也会引起柴油机过热 。此时气缸盖、气缸套、活塞组件及气门等主要受热负荷大,其机械性能如强度、韧性等急剧下降,使零件变形增加,减小了零件 间的配合间隙,加速机件磨损,严重时还会产生裂纹、机件卡住的故障。冷却水、机油温度过高会加快机油老化变质和烧损,且机 油黏度下降,套缸和活塞及主要摩擦副的条件润滑条件恶化,产生异常磨损。柴油机过热还会恶化柴油机燃烧过程,使喷油器工作 失常,雾化不良,积炭增多。

(6)在冷却水和机油油温过低的状态下运转

柴油机工作过程中,冷却水温度过低,气缸壁温度随之下降,燃烧产生的水蒸气凝结成水珠,与废气接触生成酸性物质,附着 于气缸壁,产生腐蚀磨损。实践证明,柴油机经常在冷却水温40℃~50℃下使用时,其零件磨损比正常工作温度(85℃~95℃)下运 转是大好几倍。此时,水温过低时气缸内温度低,柴油机着火滞燃期延长,一经着火,压力迅速升高,柴油机燃油粗暴,易造成零 部件的机械损坏。柴油机长期在冷却水较低温度的状态下运转,活塞与缸套的间隙大,已发生敲缸现象,并产生振动,使缸套出现 穴蚀。机油温度过低,机油黏度大流动性差,润滑部位油量不足,使润滑变差,造成摩擦副磨损增加,缩短柴油机使用寿命。

(7)在机油压力过低的情况下运转

机油压力过低,则润滑系不能进行正常机油循环和压力润滑,各润滑部位得不到充足的机油。因此,机器在行驶过程中,要注 意观察机油压力表或机油压力指示灯情况。若发现机油压力低于规定压力时,要立即停机,排除故障后再继续行驶。

(8)机器超速、超载行驶

如机器严重超速、超载行驶,柴油机将在负荷过大、转速过高的工作情况下运转,易造成工作粗暴,缸套、活塞、连杆等承受 的热负荷和机械负荷加大,易发生拉缸、烧瓦等故障。经常超负荷运转,造成气缸内长时间的粗暴燃烧,容易损坏气缸垫。

(9)熄火前猛轰油门

If a diesel engine running at high speed stops running suddenly, its huge inertia will damage the parts of the crank connecting rod mechanism and the valve mechanism, shortening the service life. At the same time, when the throttle is slammed, the fuel flows down along the cylinder wall due to excessive entry into the cylinder and it is too late for complete combustion, diluting the lubricating oil. In addition, it will also significantly increase the carbon deposits in the piston, valve and combustion chamber, causing the fuel injection nozzle to be blocked and the piston to be stuck.

(10) Sudden addition of cooling water when the temperature of the diesel engine is too high

If the cooling water is suddenly added when the diesel engine is short of water and overheated, it will cause cracks in the cylinder head, cylinder liner, cylinder block, etc. due to drastic changes in cold and heat. Therefore, when the temperature of the diesel engine is too high, the load should be unloaded first, and the speed should be increased slightly. After the water temperature drops, the diesel engine should be turned off, and then the radiator cap should be loosened to remove water vapor. Slowly inject cooling water into the water radiator if necessary.

(11) Long-term idling operation

When the diesel engine is idling, the pressure of lubricating oil is low, and the cooling effect of oil injection on the top of the piston is poor, resulting in a sharp increase in wear and easy cylinder scuffing; it can also cause poor atomization, incomplete combustion, serious carbon deposits, and sometimes even cause the valve and piston ring to be stuck , Cylinder liner cavitation. For this reason, some diesel engine manuals clearly stipulate that the idling time of diesel engines should not exceed 15-20 minutes.