Air Intake System Optimization for Passenger Car Engine 2019-26-0044
The customer expectations in the passenger car market are predominantly in the areas of engine/vehicle performance along with NVH refinement. In addition, continuously evolving regulatory emission and crash norms brings out multiple challenges on to automotive engineers. One system that has its footprints on all of the above requirements is the air intake system of the engine. In this case study, we will discuss the impact of air intake system design of a 3-cylinder gasoline engine on different attributes of engine and consequently corresponding vehicle.
In simple terms, the primary function of the air intake system is to provide filtered air to engine. However, this paper delineates how target parameters like engine performance, NVH refinement, regulatory requirements etc. are all affected by intake system geometry and location of the same in the vehicle. The intake system geometry here corresponds to air filter volume, hose lengths, cross sectional areas and the location of air filter refer to whether it is mounted on the engine top or remotely with reference to engine.
The baseline air intake system of an engine and corresponding NVH performance, packaging challenges etc. are explained. The benefits of remote mounting option vis.a.vis challenges related to air filter volume packaging, dirty duct layout and most importantly sensitivity of engine performance w.r.t clean air duct length are presented. An innovative design solution, which helped to reduce clean air duct length for our remote mounted air filter is discussed. The aspects related to snorkel placement in engine bay like prevention of water wading, hot air ingress and rodent entry are shared. Further, reduction in orifice noise and radiated noise of air filter by volume optimization, panel mode optimization and by addition of passive noise components like Helmholtz resonator and Venturi is demonstrated.
Tools like engine cycle simulation, flow simulation, structural CAE, vibration analysis, engine and vehicle testing for performance and NVH parameters were used and results are shared to build a case that air intake system optimization is a multi-disciplinary approach which is of extreme importance in this competitive market to meet customer expectations and regulatory norms.