Abstract
A simple mechanical gaseous-fuel supplementing system has produced excellent results on a variety of diesel engines, in terms of performance and fuel cost savings. The results have compared most favourably with those obtained by an expensive high-tech prototype electronic injector system, and along with a much lower cost, the mechanical system has received excellent acceptance from mechanics due to its "understandability" and ease of installation, tuning and trouble-shooting. The system has been proven on both normally-aspirated and turbo-charged engines. While the metering calibration is engine-specific, a range of adjustment allows for a safe band of engine power and diesel-substitution rates.