Filter Performance Requirements for Engine Air Induction Systems 970556
Automotive engine air intake filters are constantly being challenged to deliver higher filtration performances. The need to protect the engine from abrasive contaminants is ever increasing to achieve longer engine life and improved engine performance. This paper discusses some of the key issues affecting engine filter performance.
Currently, the SAE J726 procedure is used to test and evaluate engine air induction filters (AIF). The advantages and limitations of this procedure are discussed. Based on this procedure current engine air filtration technologies are also compared.
Engine protection requirements are also discussed relating to contaminant size and concentrations. To design robust engine air induction filters, the particle size and concentration ingested by the engine should be controlled. In addition to the overall mass (gravimetric) efficiency of the filters, the fractional size efficiency of these filters should also be measured. Fractional size efficiencies would quantify the contaminant size/concentration ingested by the engine which is related to engine wear, oil consumption, power loss etc..
Field evaluations are presented which capture the real time performance of engine air induction filters in dusty environments. Field evaluations should be mandatory to design effective and robust engine air intake filters.
New methods and improvements are briefly recommended for the SAE J726 procedure in quantifying air induction filters. The proposals are to include fractional size efficiencies in addition to the mass efficiency currently measured. Future trends in engine air induction filter systems are also discussed which may benefit from the new test proposals.