Faults caused by oil leakage in the turbocharger

The WBY-200C stabilized soil mixer has caused two malfunctions during road construction due to oil leakage from the booster.

1. The engine consumes a large amount of engine oil

This mixer needs to add 4 to 6 liters of engine oil every 8 hours of operation during construction. Moreover, the newly changed engine oil becomes sticky and black within less than two days. At first, it was thought that the oil burning was caused by severe wear of the engine cylinder liner assembly, resulting in air leakage. However, after checking the cylinder pressure and engine power, it was determined that the engine performance was normal, and there was no obvious blue smoke from the exhaust pipe. Analysis suggests that this malfunction is caused by the oil lubricating the turbocharger entering the intake manifold through the floating bearing, air seal plate and oil deflector. That is, a large amount of oil enters the intake pipe and then enters the cylinder block with the air and adheres to the cylinder wall. During the diesel combustion process, the oil is burned and forms a large amount of carbon deposits. Some of the carbon deposits are discharged from the cylinder block. Some of it adheres to the cylinder wall and enters the crankcase through various means, thereby causing excessive consumption of engine oil and making it prone to getting dirty and sticky.

2 The lifespan of the components in the airway system is extremely short, and the air pressure rises slowly

When disassembling and inspecting the air pump, oil-water separator and pressure regulating valve of the machine's braking system, it was found that there was a considerable amount of carbon deposits inside the components. The intake and exhaust diaphragms and valve cores inside the cylinder head of the air pump are all stuck together due to carbon deposits. The spring also lost its elasticity due to high temperatures. The rubber parts inside the oil-water separator have also melted. According to the feedback from the users, the newly replaced air pump cylinder head assembly and oil-water separator assembly could be used normally at the beginning. However, after more than one month of use, the above-mentioned faults occurred. Moreover, when working at night, it can be observed that the copper pipe from the air pump to the oil-water separator often turns red due to prolonged operation. Analysis suggests that all these malfunctions are caused by oil leakage from the turbocharger into the intake pipe. This is because the air inlet of the air pump is connected to the intake manifold, and the air carrying engine oil enters the air pump and its subsequent pipelines. Due to the continuous operation of the air pump and the presence of oil in the pipelines, the air passage is not unobstructed, which leads to a high temperature of the compressed air, causing the engine oil to burn and carbonize, and clogging the pipelines. This ultimately led to the aforementioned malfunction.

After replacing the turbocharger, the above two faults were eliminated.

The above-mentioned malfunction informs us that in order not to affect the overall operation of the machine and extend its service life, when operating construction machinery equipped with a turbocharger, the following aspects must be noted:

After the diesel engine starts, it must idle for more than 5 minutes before loading. Otherwise, the turbocharger will not be adequately lubricated, which will lead to excessive wear of Atlas air compressor parts.

(2) During normal operation of a diesel engine, an emergency shutdown is not allowed unless there are special circumstances. If it is necessary to shut down the engine, the engine speed must be gradually reduced to idle and run for more than 5 minutes. When such machines are under load, the rotational speed of the turbocharger rotor can reach 60,000 to 80,000 r/min. If the diesel engine suddenly stops or suddenly reduces its speed, the oil pump will either stop supplying fuel or the fuel supply will be insufficient. At this time, the turbocharger rotor is still running at an extremely high speed, which will cause excessive wear between the moving pairs and excessively high temperatures due to insufficient lubrication and cooling. It affects the lifespan of the turbocharger and even directly leads to damage.

(3) After changing the engine oil or oil filter element of a diesel engine or after it has been parked for a long time, when starting, the oil inlet joint of the turbocharger should be loosened at idle speed. Once lubricating oil leaks out, it should be tightened again and run for more than 5 minutes before loading.

(4) When replacing the oil return hose of the turbocharger, the inner diameter of the hose must be greater than 25mm and there should be no excessive bending in the middle to avoid poor oil return and affect the lubrication effect of the turbocharger.