With the implementation of my country’s sustainable development strategy, the proportion of compressed natural gas (CNG) and liquefied petroleum gas (LPG) as economical and practical green fuels in my country’s energy consumption has grown rapidly. The use of clean fuels such as CNG and LPG in place of conventional fuels by automobiles (mainly buses and taxis) has been a national key project since the “Tenth Five-Year Plan” period. Large cities with serious pollution are fully promoted. During the promotion of clean fuel, some problems related to lubricating oil also appeared, which aroused the attention of users. For example, the original engine oil is still used in the refitted vehicle engine, which often has more carbon deposits, more sludge, and shorter oil change intervals. , The engine is prone to many problems such as early wear and tear and shortened overhaul mileage. Here we briefly analyze and introduce these phenomena and countermeasures.
Gas fuel is different from gasoline and diesel. It has high purity, high thermal efficiency, high gas temperature, and clean combustion, but its lubricity is poor, and it contains a certain amount of sulfur, which is easy to cause adhesion, friction, corrosion and rust of engine related parts. Its disadvantages can be summarized as follows:
- Easy to produce high temperature carbon deposition
The gas fuel engine burns completely, and the temperature of the combustion chamber is tens to hundreds of degrees higher than that of the gasoline/diesel engine. The effect of high temperature oxidation will cause the quality and viscosity of the engine oil to drop too much and the lubrication performance will fail. When the cylinder temperature is high, the lubricating oil is easy to produce Carbon deposits lead to early combustion, spark plug carbon deposits will cause abnormal wear or failure of the engine, and may also increase NOX emissions.
- The valve components are easy to wear
The gasoline/diesel in the gasoline/diesel engine is sprayed into the cylinder in the form of mist droplets, which can lubricate and cool the valves, valve seats and other components. Make valves, valve seats and other parts dry and unlubricated, and are prone to adhesive wear. Under the action of high temperature, the high-ash additives of ordinary engine oil are very easy to form hard deposits on the surface of engine parts, which promotes abnormal wear of the engine, spark plug clogging and carbon deposits in valves, causing engine knocking, ignition loss or valve fire; resulting in engine power loss. drop, power instability, etc., and even shorten the service life of the engine.
- Easy to form harmful substances
Using ordinary engine oil, the excess nitrogen oxides in the exhaust gas cannot be resolved, and the formation of sludge will be accelerated, which will cause blockage of oil passages or formation of harmful substances such as varnish. Especially for engines equipped with EGR devices, it is very easy to cause oil quality degradation, filter blockage, viscosity and acid and alkali values out of control and other trends.