What is the main purpose of crankcase ventilation?

[DaisyLee]

The function of the engine crankcase ventilation device is to prevent oil deterioration, leakage from the crankshaft oil seal and crankcase gasket, and pollution of the atmosphere by various oil vapors. The reasons and functions of crankcase ventilation are as follows: 1. During engine operation, some combustible mixture and exhaust gases enter the crankcase through the piston rings. The condensed gasoline vapor in the crankcase will dilute the oil and degrade its performance. 2. The exhaust gases contain water vapor and sulfur dioxide. The water vapor condenses in the oil, forming foam and disrupting oil supply, especially severe in winter. 3. Sulfur dioxide reacts with water to form sulfurous acid, which then reacts with oxygen in the air to form sulfuric acid. These acidic substances not only deteriorate the oil but also corrode engine components. 4. The pressure inside the crankcase increases due to the entry of combustible mixture and exhaust gases, causing oil to leak and be lost through the crankshaft oil seal and crankcase gasket. 5. The oil vapor lost into the atmosphere increases the engine's pollution of the air. 6. Installing a crankcase ventilation device in the engine can avoid or mitigate the above phenomena.