In the field of mechanical lubrication, “engine oil” is a broad general term, referring to the lubricating oil used in various machines. However, usually when we mention engine oil, we more often refer to the engine oil specifically designed for gasoline and diesel engines.
The characteristics of engine oil focus on low-temperature performance. Take Mobil 1 engine oil as an example. It shows excellent fluidity in low-temperature environments and can ensure rapid reach to all the parts of the engine that need lubrication in cold conditions, reducing wear and starting resistance. At the same time, at relatively high temperatures, it can also maintain good lubrication and protection performance.
In contrast, gear oil mainly focuses on the working performance under high temperature and high pressure. In the gear transmission system, the pressure generated when gears mesh with each other is much higher than that inside the engine, and the working temperature is also generally higher. This requires that the gear oil can still form a strong and stable oil film under extreme conditions of high temperature and high pressure to withstand huge pressure and friction.
Because of this, under normal circumstances, the minimum applicable temperature performance of gear oil is usually higher than that of engine oil. For some vehicles, such as trucks, it is necessary to wait for the engine to run for a period of time after starting to drive the gearbox to preheat to reach the appropriate working temperature. It is also beneficial for cars to operate in this way if conditions permit. If the performance of the gear oil is not good and it cannot form an effective oil film on the gear surface, it will cause severe wear of the gears and even damage.
In special application scenarios, such as heavy-duty engineering vehicles (such as wheel loaders, forklifts) and hyperbolic gear transmission devices of high-end cars and off-road vehicles, more excellent compressive performance extreme pressure gear oil or hyperbolic gear oil is required to meet their demanding working conditions and high-load operation requirements.