Teach you maintenance skills of diesel engine turbocharger

Turbocharger is one of the important components of turbocharged diesel engine. It pressurizes the air from the air filter and increases the charge volume to improve the power of diesel. Due to the poor working environment of the supercharger, the supercharger is often replaced frequently due to ring damage and oil leakage. For example, the diesel engine on one T200 bulldozer of our company has replaced five turbochargers within one year, which makes the spare parts cost of the turbocharger alone for the bulldozer throughout the year reach 15,000 yuan. Because the cumulative downtime for replacing the turbocharger is 10 hours, which seriously affects the efficiency and economy of the bulldozer. The practice shows that the service life of the supercharger is mainly related to improper operation, nonstandard installation, poor lubrication and other factors besides the manufacturing quality.

1. Causes of turbocharger damage

(1) Poor lubrication is the main cause of supercharger ring damage. Poor lubrication is mainly manifested in the absence of lubricating oil at the lubricating part, insufficient lubricating oil, leakage of lubricating oil pipeline and deterioration of lubricating oil. The first three phenomena are mainly caused by improper operation: for example, once the engine is started, the load will be increased. At this time, the pressure and temperature of the lubricating oil cannot meet the operation needs of the supercharger, and the lubricating oil is seriously insufficient, which will cause fatal damage to the supercharger; If the diesel engine shuts down suddenly during operation, the oil pump stops working at this time, but the supercharger continues to operate under high temperature and no oil, so the heat accumulated in the supercharger cannot be dissipated, and its bearing may be worn or bitten due to overheating; If the engine runs at idle speed for a long time, the exhaust gas pressure and the air pressure at the compressor end are low (lower than the pressure of the lubricating oil in the supercharger). In addition, the speed of the supercharger is low when it runs at idle speed, which makes it difficult for each motion pair of the supercharger to form an oil film, resulting in oil leakage at the turbine end and compressor end; If the turbine rotor shaft is put into operation without oil injection before rotation, the turbine rotor oil will be poorly lubricated since installation. Lubrication deterioration mainly refers to the deterioration of the oil in the oil pan or the high temperature gas entering the floating bearing due to poor sealing, resulting in local deterioration of the lubricating oil and poor lubrication of the turbocharger.

(2) The entry of impurities aggravates the damage of the supercharger. Impurities entering the turbocharger friction pair in different paths will accelerate the wear of the floating bearing, causing the turbocharger to leak. The sources of impurities are as follows: when installing the supercharger, the water can replace the engine oil and the oil filter element of the main oil passage, so that the impurities in the engine oil cannot be removed in time; When the air passes through the air filter, the filtering effect is poor and impurities are brought in; Impurities such as carbon deposits in the exhaust pipe infiltrate from the turbine end; Impurities in the engine oil enter along the lubricating oil path; The air intake system leaks, causing dust and sediment to be sucked into the compressor casing, causing blade wear.

(3) Turbocharger works at high temperature and high speed, and its turbine and compressor blades are easy to suffer from fatigue damage due to poor working environment.

2. Main Measures for Prolonging the Service Life of Turbocharger

(1) Strictly implement the diesel engine operating procedures. When the diesel engine is started, run the engine at idle speed for 3-5 minutes, and then load it after the floating bearing reaches the working lubrication state; Before normal shutdown, the load of the diesel engine shall be reduced gradually, and the engine shall not be shut down until the turbine temperature is reduced gradually after 3-5min idle operation. The number of emergency stops shall be reduced as far as possible, and the accelerator shall not be increased during startup or shutdown, and the engine shall not idle for a long time.

(2) The supercharger installation procedures shall be strictly followed. Installation procedure requirements: clean the oil pan, replace the oil filter element of the main oil duct, and add enough oil of the specified brand before installation; Plug the lubricating oil inlet hole with a screw plug, inject a little oil into the turbine rotor shaft through the lubricating oil return hole, stretch your hand into the exhaust gas inlet of the turbocharger, and rotate the turbine rotor shaft until oil overflows from the lubricating oil return hole; Take out the plug, connect and fasten all connecting bolts and clamp screws.

(3) Strictly implement the equipment maintenance procedures. Clean the air filter every 100-150h of engine operation, replace the air filter element if necessary, and replace or clean the oil filter element at the same time; Check the quality of lubricating oil every 150-200h when the engine operates, and replace the lubricating oil if necessary.

(4) Check the equipment strictly according to the standard. Before and after operation, check whether the connecting bolts and clamp screws on the supercharger are loose, and eliminate air and oil leakage in time; Clean the oil dirt and dust of the supercharger frequently, so as to find out whether the supercharger leaks oil and air in time; Check the air filter and clean the filter element; Check whether the lubricating oil quality is normal, and replace it if necessary.

(5) Strictly implement the basic principles of “three filters” and “three cleanings” for the use of lubricating oil to ensure that the lubricating oil is clean.

(6) The key to prolong the service life of the supercharger is to strengthen training and improve the operating skills of the driver. High temperature and high speed lead to poor operating environment of the supercharger and great difficulty in lubrication, so the driver is required to master excellent operating skills and manage and use the supercharger well.

In a word, by taking the above measures, only one booster was replaced for the bulldozer in the next year, which saved 12000 yuan of spare parts cost, reduced the downtime of equipment failure for 8h, extended the service life of the booster, and ensured the good working condition of the bulldozer.