Laboratory emissions evaluations were performed on heavy-duty diesel and gasoline engines and vehicles. Results from using water injection (unstabilized macro-emulsion formed in the injection pump) on a heavy-duty diesel engine showed major reductions in particulate and NOx emissions, except during idle and light load conditions. Test work carried out on the heavy-duty gasoline engine running at high load confirmed that BaP emissions did exist, but that the levels emitted were low, and that they decreased with leaner f/a ratio. Selected maladjustments (simulating wear of inadequate maintenance) of the Cummins VTB-903 substantially increased HC, smoke and particulate emission levels. Maladjustments of the Detroit Diesel 6V-71N coach engine resulted in lower HC and NOx emission levels, but higher CO emissions, smoke, and particulate. Emissions over various chassis test cycles from three in-service transit buses proved to be highly variable from one bus to another. In addition, emissions from each bus were very test cycle-sensitive.

"May 1985"