Patent ID: 7647811
Filing Date: 2010-01-19
Classification: F01N,F02D,G01N

Abstract:
1. A solid particle counting system for measuring solid particle number concentrations from engine or vehicle exhausts in real-time, the system comprising: a diluter arrangement for receiving flowing gases containing solid particles, the diluter arrangement receiving dilution gas and mixing dilution gas with the flowing gases containing the solid particles, the diluter arrangement providing an output flow; a particle counter for measuring solid particle number concentration in a received flow; a flow splitter receiving the output flow from the diluter arrangement, the flow splitter providing a portion of the output flow to the particle counter as the received flow and providing a by-pass flow; a vacuum pump receiving the by-pass flow; and a second flow route to the particle counter, the second flow route including a valve and connecting the particle counter to atmosphere through the valve such that opening the valve during the starting of the vacuum pump reduces a pressure pulse at the particle counter caused by the starting of the vacuum pump, thereby avoiding work fluid backflow from the particle counter.