研究発表

This work investigates the potential of in-cylinder thermal stratification and fuel stratification for extending the operating ranges in HCCI engines, and the coupling between thermal and fuel stratification. Computation results are employed. The computations were conducted using a multi-zone version of the Senkin application of the CHEMKINII kinetics rate code, and kinetic mechanism for di-methyl ether. This study shows that the potential of thermal and fuel stratification for extending the high-load operating limit. However, a combination of thermal stratification and fuel stratification is not more effective than above stratification techniques for extending the operating ranges showing similar results of fuel stratification.

The novel concept for engine technology is required to deal with the environmental problems. Homogeneous charge compression ignition engine is noted by the high efficiency and low emissions. However, the homogeneous charge compression ignition engine has many problems to overcome. Many researchers have investigated the homogeneous charge compression ignition engine to improve the performance and to introduce to markets. In the present paper, the fundamental of homogeneous charge compression ignition engine and the research trends were considered.

The HCCI engine is a next generation engine, with high efficiency and low emissions. However a rate of pressure rise is a major limitation for high load range. Recently, we are able to reduce the rate of pressure rise using thermal stratification. Nevertheless, this was insufficient to produce high power. Without the higher equivalent ratio, one way to improve the power is to increase the intake boost pressure. It is suggested that the rate of pressure rise is reduced by thermal stratification and the power is increased by boost pressure at the same time. The objective of this work is to understand the characteristics of combustion, knock and emissions for using both thermal stratification and the boost pressure. The calculations are performed by CHEMKIN and modified SENKIN. As a result of increasing the boost pressure, a higher IMEP was attained while the rate of pressure rise increased only slightly in the HCCI with thermal stratification.

Delaying CA50(Crank Angle of 50％ Heat Release ) of the HCCI engine to expansion stroke can lead to high indicated thermal efficiency as well as the avoidance of knocking. However, this method could induce the problem of cycle variability. In this study, the cycle-to-cycle variation of a HCCI engine fueled with DME was investigated. Experimental parameters of each cycle, such as in-cylinder temperature, pressure and gas flow rate, were recorded by fast response system, and analyzed consequently. Moreover, the interdependency between the combustion and the performance parameters were evaluated.

Thermal and mixing stratifications have been thought as one of the ways to avoid an excessive pressure rise on HCCI combustion. The purpose of this research is to investigate the potential of thermal and mixing stratifications for reducing PRR (Pressure Rise Rate) on HCCI combustion. The pre-mixture with thermal and mixing stratifications is charged in RCM (Rapid Compression Machine). After that, the pre-mixture is compressed and in that process, in-cylinder gas pressure and chemiluminescence images are obtained and analyzed. Furthermore, experimental results are compared with the computational results calculated by using multi-zone model for analyzing these mechanisms.

The novel concept for engine technology is required to deal with the environmental problems. Homogeneous charge compression ignition engine is noted by the high efficiency and low emissions. However, the homogeneous charge compression ignition engine has many problems to overcome. Many researchers have investigated the homogeneous charge compression ignition engine to improve the performance and to introduce to markets. In the present paper, the fundamental of homogeneous charge compression ignition engine and the research trends were considered.

運輸部門の省エネルギーおよび地球温暖化ガス削減のために，エコドライブ活動が推進されている。しかしエコドライブによりCO2削減が期待されるものの，NOx等の排出ガスの排出量増大が懸念される。本研究では車載型排出ガス計測システムを搭載したディーゼル車を用いて，エコドライブがリアルワールドエミッションに及ぼす影響について解析を行った。

Introduction of heterogeneity of mixture has been thought as one of the way to avoid Knocking by reducing the pressure rise rate in HCCI Combustion. The purpose of this research is to investigate the effect of heterogeneity, especially thermal stratification and fuel strength stratification on HCCI Combustion fueled with DME and n-Butane. Thermal stratification is formed in Combustion Chamber of Rapid Compression Machine with ３ Kinds of pre-mixture has different properties. The stratified charge mixture is adiabatic compressed and on that process, in cylinder gas pressure and two-dimensional chemiluminescence images are measured and analyzed.