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Experiments of combustion observations and radical measurements in DME compression ignition engine were significant for the elucidation of DME combustion. There have been several reports on combustion observation studies of DME compression ignition engines. All of these reports were experimented with the same method observed due to the bottom view, and none of these studies was targeted on low pressure injection and/or small compression ignition engines. In this research, the combustion analysis of the small compression ignition engine with DME low pressure injection was attempted by the top view observation using the wide angle view engine scope. As a result, DME combustion using the ordinary diesel engine's piston chamber shape and material was observed. The production of the exhaust elements (OH, CHO, NO) was obtained to the time series on combustion process of the small compression ignition engine with DME low pressure injection.

In the research of DME compression ignition engine, there are a lot of reports on the high fuel pressure systems which are used in the common-rail fuel injector and others for the DME mixture formation promotion. However, the initial development-cost of these fuel supply systems will be increased for small compression ignition engines. On the other hand, it has been understood that excellent thermal efficiency of DME compression ignition engine was obtained at the appropriate fuel injection timing by using the electronic controlled injector with low pressure injection. In this paper, the stabilization of combustion on DME compression ignition engine with low pressure injection was investigated for the influence of the fuel pressure and the combustion assistance with homogeneous charge.

A hybrid combustion engine in which a premixed gasoline homogeneous charge was ignited by a small amount of injected diesel fuel under a high compression-ratio has been tested on a modified 4-stroke cycle DI engine. It was found that the premixed gasoline was effective not only for decreasing the fuel consumption but also for reducing the particulate mass emission both in the high and over load regions.

In order to boost the torque of a 4-stroke cycle diesel engine, a crankcase-supercharged 4-stroke cycle diesel engine was made and tested in the firing mode. As a result, a remarkable reduction of smoke density and brake specific fuel consumption compared with the naturally aspirated baseline diesel engine was obtained. Additionally, a Jet Air Port (JAP), which was opened and closed by piston movement near bottom dead center, was installed. The JAP utilized air furnished by the crankcase-supercharging system. A reduction of smoke density and brake specific fuel consumption compared with the naturally-aspirated baseline diesel engine was found.

A hybrid combustion engine in which a premixed gasoline homogeneous charge was ignited by a small amount of injected diesel fuel under a high compression ratio has been tested utilizing a modified 4-stroke cycle diesel engine with a pre-combustion chamber. This concept was effective not only in decreasing smoke density and fuel consumption but also in increasing engine output.

A hybrid combustion engine in which a premixed gasoline homogeneous charge was ignited by a small amount of injected diesel fuel under a high compression ratio was made by modifying a 4-stroke cycle diesel engine and was tested on a bus. It was found that the premixed of gasoline was effective not only for decreasing the fuel consumption but also for reducing the smoke density during an acceleration road test. The effect of introducing a small amount of N2 gas for supressing the diesel knock under heavy load operation was examined. These days diesel engines are widely used because of their excellent fuel economy. Particulates emitted from a diesel engines, consist of dry soot observed as smoke and the Soluble Organic Fraction (SOF) containing Polynuclear Aromatic Compounds (PAC).

In order to investigate the transient characteristics of crankcase-supercharged 4-stroke cycle engines, such engines were installed in both a motorcycle and a passenger car for on-road test. It was found that, in the starting and the passing acceleration tests, the engine speeds of the crankcase-supercharged engines increased more rapidly than that of the naturally-aspirated engine. Additionally,in 0-200m acceleration tests, the crankcase-supercharged motorcycle's time was 4.7 sec (approximately 16%) faster than that of the naturally-aspirated motorcycle.

In order to improve the volumetric efficiency of a crankcase-supercharged 4-stroke cycle engine in the high speed range, rotary disc valves were used at both the inlet and the outlet sides of the crankcase. The effects of the size of the opening and the phasing of the disc valves on volumetric efficiency were investigated and compared with a system using reed valves. It was found that a volumetric efficiency higher than 120 % could be obtained over a speed of 3000-6000 rpm, which was not possible by using the reed valve system. SUPERCHARGING SYSTEMS utilizing Roots type blowers and/or exhaust turbochargers have been used effectively for increasing the brake mean effective pressure of 4-stroke cycle engines. The authors built a prototype cranckcase-supercharged 4-stroke cycle engine, which used the underside of the piston as a supercharging pump, and confirmed the effectiveness of the concept by motoring and firing tests.

At IPC-4 (4th-International Pacific Conference on Automotive Engineering) which was held at Melbourne, Australia, in November 1987, engineering training, education, retraining, and reeducation of Japanese instructors were introduced. In 1963, The Ministry of Labor opened the International Cooperation Department, The Institute of Vocational Training, at The University of Industrial Technology through the Japan International Cooperation Agency and started reeducation and retraining courses for instructors from developing overseas countries. The authors introduced comprehensive courses with their fifteen years of experience.

4 crankcase-supercharged 4-stroke spark-ignition engine was made and tested in both the motoring and firing modes. It was found that a 20 to 30 % torque rise compared with the naturally-aspirated baseline engine was obtained in the low and middle engine speed ranges without any sacrifice in brake specific fuel consumption. Additionally, the throttle response of the modified engine was better than that of the naturally-aspirated baseline engine, and there was no deterioration in part-load brake specific fuel consumption.

Two hybrid Combustion engines, wherein a premixed gasoline homogeneous charge was ignited by a small amount of injected diesel fuel under high compression ratio, were made and tested by modifying crankcase scavenged 2-stroke cycle diesel engines, one uniflow scavenged with an open chamber and the other loop scavenged with a prechamber. It was found that the premixed gasoline was effective not only for decreasing the fuel consumption but also for reducing the smoke density both in the heavy and over-load regions. The mixing ratio of the gasoline and diesel fuels, the injection timing of the diesel fuel and the compression ratio were found to be the main factors affecting the performance of these hybrid combustion engines. The effect of inlet throttling on the brake specific fuel consumption (BSFC) in the light load region was also examined.

Two hybrid Combustion engines, wherein a premised gasoline homogeneous charge was ignited by a small amount of injected diesel fuel under high compression ratio, were made and tested by modifying open chamber and prechamber 4-stroke cycle diesel engines. It was found that the premixed gasoline was effective not only for decreasing the fuel consumption but also for reducing the smoke density both in the heavy and over-load regions. The mixing ratio of the gasoline and diesel fuels, the injection timing of the diesel fuel and the compression ratio were found to be the main parameters affecting the performance of these hybrid combustion engines. The effect of introducing a small amount N2 gas for suppressing the diesel knock in the heavy load region also was examined.

Automotive industries is a major and synthetic industries now in Japan and have a large effect on the Japanese economy. It is wellknown that the Ministry of Transport has played an important role in the advent of the prosperity of Japanese automotive industries, however, the role of the Ministry of Labor was not always known. It maybe said that the success of Japanese automotive industries has been maintained by innumerable well-trained servicemen and automechanics, in other words, by many instructors who educated and trained them. In this paper, the Japanese public vocational, training systems including the unique instructor education, training and reeducation, retraining at the Institute of Vocational Training are introduced.

In order to reduce the knock of spark-ignition engines in the heavy load region, the effects of EGR on engine performance were investigated on two engines, one with a turbocharger and the other naturally aspirated with a high compression ratio. It was found that EGR was effective not only for reducing the knock, but also for improving the brake specific fuel consumption compared with the ignition timing retarding system.

In order to obtain the limiting delivery ratio curve, the relationships between the delivery ratio and the engine speed were investigated on crankcase-scavenged 2-stroke cycle engines by varying through wide limits the effective angle-areas Fia(e) of the inlet ports. It was found that the mean inlet Mach number Mim, already reported by the authors using 4-stroke cycle engines, showed well the characteristics of the limiting delivery ratio, and when Mim approached a limiting value the delivery ratio decreased hyper-bolically with an increase in engine speed.

In order to reduce the diesel idle knock, the effects of EGR on the idling characteristics were investigated on a passenger car-equipped with an EGR Idle Knock Reduction System developed for practical use. It was found that EGR was effective not only for reducing idle knock but also for decreasing fuel consumption, smoke density, exhaust emissions and engine vibration. Moreover, the practical range and possibility of the EGR Idle Knock Reduction System were found by clarifying the relationship between EGR, injection timing, cooling water temperature, noise level and fuel consumption.

As a mechanical supercharging system for 4-stroke cycle engines, crankcase-supercharging seems attractive because of its low production cost and simple construction. Therefore, a crankcase-supercharged 4-stroke cycle spark-ignition engine was developed and tested in both motoring and firing modes. It was found that the motoring volumetric efficiency could be increased over the entire engine speed range, but the increase was more noticeable at lower engine speeds. In the firing mode it was proved that a favorable throttle response and a 20 to 30% torque rise could be obtained by crankcase-supercharging without sacrificing the brake specific fuel consumption of the naturally aspirated baseline condition.

In order to investigate the air flow characteristics through poppet inlet valves, the static and dynamic flow coefficients were measured by varying through wide limits the angle-areas and the opening periods of the valves. As a result, it was found that when the angle-area was fixed, a valve having a lower maximum valve lift always showed better flow characteristics under both static and dynamic conditions. Also, a parameter which satisfactorily correlated the static and dynamic flow coefficients was found.

On 4-stroke cycle engines, the authors reported that under certain conditions the cylinder pressure, measured during the suction stroke with a low-pressure pickup, dropped below the critical pressure. Noting this considerable negative cylinder pressure during the suction stroke, the authors devised a Jet Air Suction Port (JASP), which was opened and closed by piston movement near bottom dead center. As a result, it was possible not only to burn lean mixtures steadily, but also to decrease the fuel consumption 10 to 30 % at idle by the jet air flow generated automatically from the JASP. Reductions in THC, CO and NO at idle were also noted.

In order to improve fuel consumption, the effects of cylinder cutoff on engine performance were investigated on a 4-stroke cycle in-line 6-cy linder gasoline engine. It was found that the cylinder cutoff obtained by deactivating both the inlet and exhaust valves was very effective for reducing the fuel consumption at part-load and idle, as both the pumping power for the inlet and the power for activating the inlet and exhaust valves were noticeable decreased.