Search Results

In June 2005, the United States Environmental Protection Agency (USEPA) signed a final rule implementing in-use testing requirements for heavy-duty diesel (HDD) engines. The program requires manufacturers to measure gaseous and particulate matter (PM) exhaust emissions from diesel engines using portable emission measurement systems (PEMS) installed on vehicles. In order to measure PM emissions, a cooperative contract between Sensors, Inc. and the USEPA was commenced to develop a Proportional Particulate Mass Device (PPMD). It is comprised of three key elements: a micro-proportional sampling system (MPS) incorporating an exhaust flow-meter (EFM) and an eight element quartz-crystal microbalance (QCM) to measure particulate mass. Evaluation of the exhaust flow meter (EFM) at third-party facilities have shown that the mass emission data and flow data produced with the EFM correlates extremely well with traditional (non-portable) constant volume sampling (CVS) certification systems.

The EPA is developing a new generation emissions inventory model, MOVES (Motor Vehicle Emissions Simulator). The first version of the model outputs fuel consumption based on available modal data. However, due to the limited heavy-duty vehicle data, MOVES pollutant (CO, HC, NOx) emission rates will need to be supplemented with rates determined with the Physical Emission Rate Estimator (PERE). PERE combines vehicle tractive power together with vehicle powertrain parameters specific to the class of vehicle; the vehicle weight, shape, engine type, and transmission. Analysis of in-use data for heavy-duty diesel tractor-trailer vehicles, city transit diesel buses, and dynamometer non-road diesel engines has enabled a determination of diesel engine friction and indicated efficiency and transmission shift schedules for these engines and vehicles. These model parameters and a comparison of the model results to measured fuel consumption and CO2 emissions are presented.