Measurement Methods In Development of High Efficiency Engine Blow-by Aerosol Separation Systems.

摘要

By 2012 it is estimated that diesel engine production will reach 30M units/yr. Unchecked, emissions of crank case blow-by gases from commercial vehicles alone would exceed 50K tonnes/yr of used engine oil aerosols. By enforcing increasingly stringent emissions targets, legislators globally are committing engine manufacturers to find the technological advancements necessary to control blow-by venting and minimise its consequential effects on human and environmental health. To avoid venting to atmosphere, blow-by gases are often returned to the air intake of a diesel engines turbo compressor via an oil aerosol separator. Any oil remaining contaminates the compressor and results in a degenerative loss of boost pressure. For many manufacturers future emissions control measures for tailpipe Nox and particulate depend heavily on increasing turbo boost pressures and maintaining precise control over engine air intake mass flows. Achieving and maintaining higher levels of blow-by separator performance throughout the life of a vehicle has become imperative. In order to deliver products capable of meeting the challenges our industry is facing a detailed understanding of the composition of blow-by aerosols is important. This paper will describe how measurement of particles between 0.03 and 10 microns improves our understanding of the importance of fine aerosol separation. By focusing on separator performance within the 0.03 to 0.7 micron range valuable gravimetric efficiency improvements can be achieved. The paper will also describe how characterising the fractional separation efficiency of a CCV improves our ability to predict on engine gravimetric performance