Technical Paper
Experiences with a Mini-Dilution System for Engine Homologation and Development
1994-11-01
942418
The full-flow CVS dilution system is defined by the US EPA for particulate measurement of Heavy-Duty (HD) Diesel engines. Such systems are bulky and expensive. The EEC (1), Brazil and many other countries have therefore accepted the use of so-called “Partial-Flow Dilution Systems” (PDS) for homologation of HD engines. The ISO TC70 (2) committee even recommends such systems for the emissions measurement of Off-Road Diesel engines. Such systems sample and dilute only a fraction of the total exhaust, therefore they are much smaller than a full-flow CVS. However, it is required that the most important properties and conditions of a full-flow CVS systems are also fulfilled by a PDS. Therefore an accurate sampling and dilution control must be implemented in all Partial-Flow Dilution Systems (which makes such systems more complicated than a full-flow CVS). Various types of control have been developed and are described in the EEC and ISO regulations.