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A Direct Injection Stratified Charge Rotary Engine ( DISC-RE ) with a pilot flame ignition system has been studied to find the possibility of simultaneous reductions of fuel consumption rate and HC exhaust gas emissions. Firstly, combustion characteristics in a model combustion chamber, which simulates the DISC-RE were examined from the viewpoints of calculation and experiment. The high speed photography and the indicated pressure analysis were experimentally performed while numerical calculations of the mixture formation and combustion processes were also carried out. As a result, it has been found that the combustion using the pilot flame ignition system is much activated and a better ignitability is attained under lean mixtures than using a spark ignition system. Secondly, a single rotor with 650 cc displacement DISC-RE was built as a prototype. Combustion characteristics and its performance were tested using a combustion analyzer.

A new DISC combustion system with a pilot flame for ignition was analyzed by using a model combustion chamber of a Wankel type rotary engine. A two-stroke diesel engine's cylinder head was replaced with this combustion chamber to simulate temporal changes of air flow and pressure fields inside the chamber as in actual engines. Two types of fuel injection systems were tested to obtain combustion characteristics such as the heat release rate. Direct photographs of spray and combustion were analyzed to understand the mixture-formation process of the main spray and to see the flame temperature distribution and flame moving velocity vectors. In order to understand the mixture-formation process, numerical calculations were made using a gaseous fuel. Finally, the effect of the fuel characteristics on combustion was examined using diesel fuel and n- hexane.

The fuel economy was sharply improved from our 1976 model rotary engine cars mainly through modifications to the engine and improvements in the reactivity of the thermal reactor system. The progress of our development on these items of improvement and their effects are presented in this paper. Our advance program includes several development items in addition to the above, and the progress of development on these items and their future prospects are also presented.

Based on a 1982 model passenger car powered by a 1490 cm3 4-cylinder engine, a concept car has been designed to achieve a substantial fuel economy improvement without sacrificing vehicle performance. The deisgn factors affecting the fuel efficiency of the engine and the vehicle were picked up and improved via experimental analyses. As the cumulative effects of the modifications implemented, the concept car has virtually achieved a fuel economy improvement goal of 40%. A simulation program was carried out to determine the fuel economy contribution of each design factor modified for incorporation in the concept car, thereby identifying the areas to be concentrated on for practical application.