Search Results

A proportional sampler for vehicle feedgas and tailpipe emissions has been developed that extracts a small, constant fraction of the total exhaust flow during rapid transient changes in engine speed. Heated sampling lines are used to extract samples either before or after the catalytic converter. Instantaneous exhaust mass flow is measured by subtracting the CVS dilution air volume from the total CVS volume. This parameter is used to maintain a constant dilution ratio and proportional sample. The exhaust sample is diluted with high-purity air or nitrogen and is delivered into Tedlar sample bags. These transient test cycle weighted feedgas samples can be collected for subsequent analysis of hydrocarbons and oxygenated hydrocarbon species. This “mini-diluter” offers significant advantages over the conventional CVS system. The concentration of the samples are higher than those collected from the current CVS system because the dilution ratio can be optimized depending on the fuel.

Instruments and analytical techniques are described for in-vehicle monitoring of amounts of air (void fraction) in engine coolant systems and for evaluating the performance of degas reservoirs. This method, based on electrical conductivity measurements of flowing air / coolant mixture, provides measurement, acquisition and display of coolant system temperature, pressure, flow rate, instantaneous void fraction and rate of air removal by degas bottle. Embedded temperature compensation equations are used for essentially real time display of the void fraction.