An air oil separator is a critical component in the crankcase ventilation system of many internal combustion engines. Its primary function is to filter oil mist out of the blow-by gases that escape past the piston rings into the crankcase. Without this component, the oily mixture would be routed to the intake manifold, leading to excessive carbon buildup on valves and combustion chambers.
How an Air Oil Separator Works
During normal operation, high-pressure gases generated by combustion leak past the piston rings and move into the crankcase. These gases, known as blow-by, contain oil droplets and particulate matter. The air oil separator intercepts these gases and uses several methods to capture the oil before the cleaned gas is either vented to the atmosphere or routed back into the intake system. The separated oil is drained back into the oil pan via gravity or a small passage, ensuring it is not wasted and maintaining proper lubrication levels.
Benefits of Installing an Air Oil Separator
Installing a high-performance air oil separator offers several advantages for engine longevity and performance. The most significant benefit is the reduction of oil consumption, which saves money and prevents the engine from running low on lubrication. Furthermore, by keeping oil out of the intake tract, it prevents the formation of carbon deposits on the intake valves, which can cause rough idling and reduced efficiency. This results in a cleaner engine internals and improved overall reliability.
Performance and Efficiency
Engines that are equipped with effective separation systems often experience better combustion efficiency. When the air entering the combustion chamber is free of oil mist, the air-fuel ratio remains more precise. This allows the engine control unit to maintain optimal tuning, which can translate to slightly increased power output and improved fuel economy. It also protects critical components like mass airflow sensors and turbochargers from oil contamination that can cause failure.
Common Applications
While many modern vehicles come with integrated crankcase ventilation filters, aftermarket air oil separators are popular in the performance tuning community. They are frequently added to turbocharged engines and high-mileage vehicles. These devices are also essential for engines that have been modified to produce higher levels of blow-by, where the stock system is no longer adequate to handle the volume of contaminated gases.
Coalescing Separators Use media to merge small oil droplets into larger ones for easy draining. High-performance and turbocharged engines.
Coalescing Separators
Use media to merge small oil droplets into larger ones for easy draining.
High-performance and turbocharged engines.
Cyclonic Separators Use centrifugal force to spin the gases and separate oil via momentum. Applications where space and complexity are concerns.
Cyclonic Separators
Use centrifugal force to spin the gases and separate oil via momentum.
Applications where space and complexity are concerns.
Maintenance Considerations
Proper maintenance of an air oil separator is essential for optimal function. Over time, the collected oil will fill the reservoir, and if not drained during oil changes, it can cause excessive pressure within the system or allow oil to flood the intake. Most manufacturers recommend draining the separator at every standard oil change interval. It is also important to inspect the hoses for cracks or leaks to ensure the vacuum seal remains intact.
Choosing the Right Unit
When selecting an air oil separator, it is important to consider the engine displacement and the expected volume of blow-by. Units are available in various sizes and configurations to suit different applications. Look for units constructed from durable materials such as aluminum to resist heat and pressure. Additionally, verify the location of the unit to ensure proper routing of the hoses without creating stress points or kinks in the plumbing.
