In the search for a way of increasing fuel economy and reducing hydrocarbon emissions of two-stroke-cycle loop-scavenged engines, investigations have been underway to evaluate various aspects of the digital engine concept.
A two-stroke-cycle, loop-scavenged single cylinder engine was modified by replacing the head with a head having three subchambers and incorporating a distributing pump fuel injection system. The fuel injection system allowed one subcharaber to be operated at a time.
The quantum combustion system demonstrated both lower fuel consumption and lower hydrocarbon emissions than a conventional homogeneous charge engine. The experimental evidence also indicates that the combustion essentially occurred in the one chamber into which fuel was injected. This work demonstrated the feasibilility of establishing stratified charge combustion by mechanically separating the regions of air from the regions of air/fuel mixtures by means of subchambers.