Development and Test of a Fractional Sampling System for Diesel Engine Particulate Measurement

Diesel engine particulate certification, heretofore limited to on-highway truck engines, will be expanded in scope beginning in 1996. “Mini-dilution” tunnels have been the European and Japanese systems of choice for dilute particulate emissions certification for non-U.S. truck diesel engines. However, repeatability, steady-state test correlation versus full dilution systems, portability, sampling time, size, and system cost have precluded universal industry and regulatory acceptance of existing “mini-system” designs. To address corporate particulate measurement needs, the author developed a device known internally as the “Micro-Dilution Particulate Measurement System,” which meets the following objectives: (1) correlation with full dilution systems within ISO 8178 equivalency standards, (2) short sampling time, (3) reduced setup effort, and (4) excellent portability. Since the system is a true fractional sampler, it is insensitive to engine size, requiring only a simple stack probe change to provide accurate, representative steady-state diesel stack sampling on any size diesel engine.