What is the reason why the engine of Komatsu excavator emits blue smoke?

The engine of Komatsu excavator emits blue smoke, which is mainly caused by burning oil. There are two main reasons for burning engine oil:

1, normal engine wear. Due to the service life of the engine, the wear between the working parts becomes larger, which leads to the increase of the fit clearance and the decrease of the sealing performance of the sealing element to the engine oil, which makes the engine oil leak into the cylinder through other parts and participate in the combustion, resulting in blue smoke.

2. Abnormal engine wear. Because the friction parts are not fully and effectively lubricated during the use of the engine, for example, the engine works without oil for a long time; The oil and mechanical filter element have not been replaced for a long time; When the engine is cold and the throttle is working, it will cause abnormal wear of the engine, leading to oil leakage and combustion, resulting in blue smoke.

Common fault location:

1, between valve and valve oil seal.

Due to the relative motion between the valve and the valve oil seal accompanied by long-term friction, the gap between the valve and the valve oil seal will gradually increase with the increase of engine service time, which will lead to the oil directly leaking into the engine cylinder through the gap between them, participating in combustion and producing blue smoke.

2. Between the piston and the cylinder.

The reason why the engine can ensure sufficient compression ratio and sufficient lubrication between the piston and the cylinder is not only the accurate control of the gap between the piston and the cylinder, but also the oil film formed by the piston ring after being oiled. However, if the maintenance of the engine is neglected, the fit clearance (end clearance) between the engine piston ring and the cylinder may become larger. If the gap between the piston ring and the cylinder increases, the sealing performance of the piston ring to the engine oil will decrease, so that the engine oil will enter the cylinder through the gap and burn and produce blue smoke. Sometimes, due to the "fit" of the piston ring, the engine oil will leak and burn, resulting in blue smoke.

3. The seal of turbocharger turbine shaft is damaged.

Because the turbocharger is a high-speed running component, it is necessary to obtain sufficient and stable engine oil in the working process to ensure smooth lubrication and heat dissipation and normal operation of the turbocharger components. However, when the turbocharger turbine shaft is not tightly sealed, it will lead to oil leakage into the turbocharger air passage.

(1) If the oil enters the turbine side, it will burn under the action of high-temperature exhaust of the engine, resulting in blue smoke from the engine. In this case, a large amount of carbon deposits will be produced in the air passage of the supercharger, which will increase the workload of the supercharger and increase the probability of high temperature for a long time. If the situation is serious, the supercharger will burn out due to overheating.

(2) If the engine oil enters the impeller side of the compressor, the engine oil will enter the air inlet, reach the cylinder, burn and produce blue smoke. Engine oil entering the cylinder for combustion will increase the generation of carbon deposits on the engine piston. In the long run, it will increase the occurrence of engine jitter and easily increase the probability of engine knocking.

If the turbocharger leaks oil and causes blue smoke, it is necessary to replace the seal of the turbocharger in time to prevent the turbocharger from being scrapped due to poor lubrication and heat dissipation, resulting in economic losses.

4. Add too much oil.

Due to the excessive addition of engine oil, the oil level rises, which intensifies the "upward channeling" of engine oil and increases the possibility of engine oil entering the cylinder for combustion. This situation can easily cause the engine to produce a lot of blue smoke. In this case, the blue smoke can be eliminated by releasing excessive engine oil.