What is the function of crankcase ventilation?
3 Answers
The main functions of crankcase ventilation are: 1. Prevent engine oil from deteriorating. 2. Prevent leakage from the crankshaft oil seal and crankcase gasket. 3. Prevent various oil vapors from polluting the atmosphere. 4. Prevent excessive crankcase pressure, extend the oil change interval, reduce component wear and corrosion, and prevent engine oil leakage, making crankcase ventilation essential. When the engine is running, some combustible mixture and exhaust gases leak into the crankcase, which can dilute the engine oil, degrade its performance, and reduce its lubricating properties. If the exhaust gases contain water vapor and sulfur, they can form sulfuric acid, which corrodes engine components. Therefore, crankcase ventilation is necessary.
The crankcase ventilation system primarily manages internal engine pressure to prevent the accumulation of harmful gases such as blow-by gases, water vapor, and acidic substances. It redirects these gases back into the intake system for re-combustion, reducing pollutant emissions. Long-term lack of maintenance can lead to oil degradation, engine corrosion, and even increased fuel consumption. Based on my experience with older vehicles, regular inspection of the PCV valve is crucial; failure can cause smoke, reduced power, and compromised driving safety. It also helps improve exhaust emissions to meet environmental standards, ensuring smoother engine operation. In cold climates, the system prevents water vapor condensation from freezing and damaging the engine. In short, a small component with significant impact—don't overlook it.
The function of crankcase ventilation is reflected in both environmental and technical aspects. Technically, it maintains low pressure in the crankcase and discharges unburned hydrocarbons from blow-by gases through the PCV valve, preventing excessive pressure that could damage seals or contaminate engine oil. Environmentally, the system recycles these gases into the combustion chamber to be burned, significantly reducing the emission of harmful exhaust gases such as CO and HC. Having studied automotive emission regulations, I can confirm this is an essential feature of modern engines; without it, engine oil would oxidize faster, forming sludge and shortening engine lifespan. Proper use can also improve fuel efficiency, making it a top priority in my vehicle's routine maintenance.
