Development and Testing of a Compact and Mobile CVS System for Passenger Car Particulate Measurement

This paper reports on the development and testing of a compact and mobile CVS system for the measurement of particulate matter emissions of diesel passenger cars. It consists of the same components as a conventional CVS system but needs much less space. Reducing the size of the CVS system was achieved by the optimization of the turbulent flow in the dilution tunnel by the use of an optimized mixing chamber, in which the engine exhaust gas is diluted with filtered ambient air. The measures taken to improve the turbulence in the dilution tunnel lead to the same effect as a tunnel with dimensions according to the legislative regulations. All the components of the mobile CVS system are arranged in a very compact design, so that the new system has a size of only about (1.70 x 0.80 x 2.10) m. Due to the mobility which is possible with such a design, the new system can be quickly adapted to different engine and vehicle test cells for passenger cars.

The new system was tested in transient test cycles and in steady state tests on a modern Euro 2 diesel engine and on a modern diesel passenger car meeting Euro 3 legislation. The results were compared to fully legislation compliant, conventional CVS systems and showed a good correlation between the new system and the conventional system used for reference.