Patent ID: 6959590
Filing Date: 2005-11-01
Classification: G01N

Abstract:
1. In a portable self-contained system for sampling and analysing engine exhaust emissions of a mobile or stationary emission source in which the system has an inlet pipe for receiving an emission sample, a dilution tunnel having a plurality of sampling probes within said dilution tunnel for withdrawing controlled volumes of diluted engine exhaust upstream from said dilution tunnel, emissions analysing means downstream of said tunnel, control means for introducing dilution air into said tunnel, a sampling probe upstream of said dilution tunnel in operative association with said control means, characterized by: air inlet measuring means measuring air inlet flow rate into an engine, a plurality of pump means with which to draw a sample of said diluted engine exhaust through said probe means, and control means comprising a variable controller for controlling the volume of dilution air of said exhaust in inverse proportion to the ratio of engine air inlet flow rate and the engine inlet air flow rate at engine idle.