Emissions From Heavy-Duty Trucks Converted to CNG

Abstract

Emissions are reported for four heavy-duty trucks, which were converted to operate on compressed natural gas fuel. Two 1988 model year Ford F700 Series trucks equipped with 7.0 L gasoline engines and two 1986 model year GMC trucks equipped with DDC 8.2 L diesel engines were tested on a heavy-duty chassis dynamometer in a baseline condition and again after conversion to natural gas. The vehicles were tested over the EPA Urban Dynamometer Driving Schedule for Heavy-Duty Vehicles and at no-load curb idle. Regulated emissions of NOx , CO, HC, and diesel particulate, along with nonmethane hydrocarbons, are reported in grams/mile. Fuel economy is reported in energy-equivalent miles per gallon of gasoline or diesel fuel.