Buses in the town and in the region for public transport mostly use the diesel engine. The diesel fuel is relatively cheap by a low tax, but causes problems for the environment. To prevent the damaging process of the exhaust fumes caused by the diesel fuel, a new kind of engine has been developed running on natural gas, especially for the use in such buses. A prototype of this motor was set in a bus and tested. The exhaust emissions were very low. The nitrogen oxide emission proved to be a factor ten lower, the carbon monoxide emission was a factor twenty five lower and the emission of higher hydrocarbonates even with a factor hundred. Soot and stench were not present. The emission proved to be under the future rigid American specifications for such heavy vehicles.
Abstract