Turbocharging a Bi-Fuel Engine for Performance Equivalent to Gasoline

A bi-fuel engine capable of operating either on compressed natural gas (CNG) or gasoline is being developed for the transition to alternate fuel usage. A Saturn 1.9 liter 4-cylinder engine was selected as a base powerplant. A turbocharger was installed to increase the density of the intake charge and thereby regain the volumetric efficiency lost with CNG. Reductions from baseline in hydrocarbon and carbon dioxide emissions were achieved at power levels equivalent to and slightly higher than the baseline. Brake thermal efficiency values were not significantly different in any case. 8 refs., 12 figs.