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A structural ceramic diesel engine has the potential to provide low heat rejection and significant improvements in fuel economy. Analytical and experimental evaluations were conducted on the critical elements of this engine. The structural ceramic components, which included the cylinder, piston and pin, operated successfully in a single cylinder engine for over 100 hours. The potential for up to 8-11% improvement in indicated specific fuel consumption was projected when corrections for blow-by were applied. The ringless piston with gas squeeze film lubrication avoided the difficulty with liquid lubricants in the high temperature piston/cylinder area. The resulting reduction in friction was projected to provide an additional 15% improvement in brake specific fuel consumption for a multi-cylinder engine at light loads.

Diesel engine particulates collected on a trap cause the exhaust back pressure to increase and adversely affect fuel economy and vehicle performance. Therefore, a trap must be periodically regenerated by oxidizing the collected particulates. Several techniques for regenerating a Diesel particulate trap are discussed. Regeneration was achieved with high speed and high load engine operation. Lead, added to the Diesel fuel, acted as a catalyst and reduced the ignition temperature of particulates collected on a trap by about 300°F. Throttling the intake air flow increased exhaust temperature to facilitate regeneration at moderate vehicle speeds. An externally fueled burner provided regeneration over the widest range of engine operating conditions, including idle.

Capabilities of DI diesel engines for passenger cars were evaluated in a research program. Three experimental DI diesel engines, a naturally aspirated 2.4L four cylinder engine and a naturally aspirated and turbocharged 1.3L three cylinder engine, were designed, built and developed. Design parameters and calibrations were determined for optimized power and fuel economy at low emission levels. The effects of cylinder displacement and turbocharging were evaluated. Vehicle tests showed that the DI diesel engine provided an 11 to 13% improvement in fuel economy relative to the IDI diesel engine. The low mileage objectives assumed for the 1985 Federal emission standards were met at vehicle test weights up to 3125 lbs.

Engine-fuel relationships of the Ford PROCO stratified charge engine have been examined. The test program was conducted in three phases to assess the interrelationships between exhaust emissions, fuel economy, octane requirement, and fuel properties in an experimental, research, single cylinder, stratified charge PROCO (programmed combustion) engine. In Phase I, tests were conducted at a steady-state speed-load condition to determine the effect of engine calibration parameters on emissions and fuel economy after an initial evaluation of engine operation with three different ignition system configurations. A dual ignition system produced reliable, misfire-free operation with the dilute mixtures and high EGR rates tested. In Phase II, five fuels with significantly different volatility properties and composition were tested to determine their effect on emissions and fuel economy of the PROCO engine.