Universal Air-Oil Separator for Use in Modern Turbocharged Direct Injection Engines

• Joshua Hoffman
• Georgi Bilyarski
• Krzysztof Kijak
• Adrian Walkosz
• Neel Patel

The current state-of-the-art high performance turbocharged engines use direct injection rather than port injection. This allows for the fuel to be directly injected into the cylinders rather than behind the intake valves. With factory positive crankcase ventilation systems (PCV) being routed through the intake tract, much of the oily vapor and other combustion byproducts ends up being stuck on the intake valves or in the combustion chamber. This causes issues with valve seals and also lowers the octane rating of the fuel. Since fuel is no longer sprayed onto the intake valves, the carbon deposits never get cleaned. Therefore, a catch can or an air-oil separator is a crucial part of these types of engines. In order to design a truly universal catch can that can also be used as an air-oil separator; we researched current filtering methods while keeping cost in mind. Five different filtering methods were considered, and the best design was chosen based on potential cost, manufacturability, filtering effectiveness, and packaging. Computational Fluid Dynamics (CFD) was used to determine the properties of the catch can that determines its filtering efficiency. Pressure drop, temperature distribution, and fluid movement were found for the chosen design, and a prototype was manufactured using the engineering drawings made. Once the prototype was constructed, further testing and benchmarking of its filtering effectiveness were performed. Results from this testing allowed us to adjust various parameters of the prototype to achieve a better result. The final design allows for a working universal catch can and air oil separator to be mass manufactured and used on all modern-day engines.