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In order to investigate the combustion process of a Direct Injection Stratified Charge Rotary Engine (DISC-RE), a statical model combustion chamber was made and 2 stroke diesel engine was used as a Rapid Compression Machine (RCM) for the purpose of fundamental study of some characteristics of DISC-RE operation. This paper present some data on air flow in the model combustion chamber, some films of fuel injection spray, combustion flame propagation, using high speed camera, and test datas of combustion characteristics. From these films, it was clarified what happen inside of the rotor pocket. Generally to take a photograph inside of combustion chamber is very difficult using actual engine, because the combustion chamber moves toward rotational direction, so, using the static combustion chamber is very effective in the study of the fundamental process.

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 model combustion chamber of Wankel type rotary engine was employed to study the DISC RE system. A two-stroke Diesel engine's cylinder head was replaced with this combustion chamber to simulate temporal change of air flow and pressure fields inside the chamber as an actual engine. The base engine was motorized to operate as a continuous rapid compression and expansion machine. Pilot fuel spray was injected onto a glow plug to form a pilot flame and it ignites the main fuel spray. The ignitability of pilot fuel, mixture formation process, ignition process of main fuel by pilot flame and the effect of pilot and main injection timings on combustion characteristics were examined.

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.

A new idea for controlling the in-cylinder mixture formation in SI engines is proposed. This concept was developed by applying the results of numerical calculations. Fuel that is directly injected into the cylinder is transferred toward the cylinder head to form a mixture stratification by using the in-cylinder gas motion that is generated by the interaction between the swirl and squish flows inside a combustion chamber. At first, the flow characteristics were measured in the whole in-cylinder space using an LDV system. Also, numerical calculations of the in-cylinder flow were made using measured data as the initial conditions. Secondly, the local equivalence ratio at several points inside the combustion chamber was measured by using a fast gas sampling device.

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.

In response to today's market demands, technological development for high-powered rotary engines has been under way for application to passenger models and racing engines. This paper, describes first the development work devoted to achieve higher output, including a turbocharger system, tuned induction and exhaust systems, combustion chamber shape, ignition system. New technologies used for components so as to cope with higher power output, thus securing engine reliability and durability are discussed. Those technologies include a new surface treatment for improved lubrication of the trochoid surface, reduction in rotor gear stress, and optimization of the spark plug and igniter system. Those development efforts resulted in production of: TURBO CHARGED 573 cc × 2 rotors, 165 ps/6500 rpm engine for passenger car and 573 cc × 2 rotors, more than 260 ps/9000 rpm engine and 654 cc × 2 rotors, more than 300 ps/9000 rpm engine for racing.

New material and processing technologies were developed for main components of the rotary engine to establish its reliability and durability. The components discussed in this paper are the rotor housing, side housing, and sealing elements. Also described are the material and processing technologies which resolved problems about their strength, rigidity, wear, etc.

The authors have experimentally produced a new type of Rotary Valve (ca11ed R.V.) which has a unique gas sealing mechanism. In this study, first, the mechanical loss in the valve train was measured comparing to that of the poppet valve drive train, and it was found that the mechanical loss of rotary valve train is much lower level. Secondary, three dimensional numerical calculation of the flow field from the intake-port to in-cylinder during the intake stroke was carried out. As a result, it was found that the flow field is very complicated due to the interaction between the moving piston and valve and that the profiles of “valve notch” and intake port affect the flow field and then, the modification of profile with a round edge form of the “notch” enables higher mass flow rate.

A Direct Injection Stratified Charge Rotary Engine (DISC-RE) with a pilot flame ignition system which has high ignition energy, large flame contact area and long duration of ignition source, has been examined comparing with a spark ignition system, using a model combustion chamber simulating a DISC-RE. As a result, it was found that the combustion using the pilot flame ignition system was activated and that a better ignitability was attained under lean mixture conditions than using a spark ignition system. To analyze these experimental results, numerical calculations of the mixture formation and combustion process were carried out. Numerical analyses proved that the pilot flame ignition system was superior to the spark ignition system as the pilot flame ignition made large-area ignition source and large inflammable mixture region. Finally, a single rotor with 650 cc displacement DISC-RE was built as a prototype.

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.