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Research on the Catalytic Plasma Torch (CPT) ignition system was conducted this last year at BKM, Inc. in San Diego. The results showed that under certain conditions CPT can not only time ignition properly, but also extend the lean stability limit. This concept is based upon compression ignition of the charge in the CPT's integral pre-chamber. Compression ignition is induced by timed catalytic reduction of the pre-chamber's activation energy. This produces almost instantaneous combustion in the pre-chamber and is divided into multiple high velocity torches to rapidly ignite the main chamber charge. The timing of the ignition event is based on the location of the heated catalyst in the pre-chamber and the mass of the charge inducted into the cylinder. The base timing curve can be modified via current control which effects the catalyst activity. Dynamic modification of the timing event is accomplished by using the catalyst as an in-cylinder hot wire anemometer.

Additional data has been analyzed on the effect of engine size on thermal efficiency. The comparison has been expanded to show the trends separately for engines developed by several different manufacturers. The data confirm the conclusion that engines below 2.0 liters per cylinder seem to deteriorate in fuel economy faster than would have been predicted from the behavior of larger engines. It is postulated that such deterioration results from a combination of less than optimum fuel spray, wall wetting, and perhaps a greater heat transfer loss than was anticipated. The paper focuses on engines in the size range under two liters per cylinder and addresses some of the problems to be resolved. Means for generating and controlling fuel spray and injection rate shape are presented along with experimental data on fuel sprays and engine combustion.

An electronic fuel injection system for diesel engines has been adapted for dual fuel applications. The simplified and commercially practical system capitalizes on using standardized hardware and software modified for the dual fuel conversion kit Using the conventional diesel pump for pilot injection, electronic injectors provide timed pulses of gas for each cylinder. The system has been successfully applied to both naturally aspirated and turbocharged versions of the Mercedes OM-352 diesel engine and has been placed in service in transit bus applications. Performance data shows over 90% displacement of diesel fuel with the same power and fuel economy as the base diesel engine. Initial reports from the field indicate excellent performance and drivability as well as smoke-free exhaust when in the dual fuel mode.

The potential for improving the efficiency of a heavy duty turbocharged diesel engine by closed loop Air-Fuel Ratio (AFR) management has been evaluated. Testing conducted on a 12 liter diesel engine, and subsequent data evaluation, has established the feasibility of controlling the performance through electronic control of air management hardware. Furthermore, the feasibility of using direct in-cylinder pressure measurement for control feedback has been established. A compact and robust fiber optics sensor for measuring real time in-cylinder pressure has been demonstrated on a test engine. A preferred method for reducing the cylinder pressure data for control feedback has been established for continued development.