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Research on Ignition

Introduction

Automobile engines have significant effect on environment and the improvement of the thermal efficiency and reduction of pollutant emission are critical problems to be solved for sustainable society. We focus on combustion phenomena, especially on ignition, and try to improve the ignition characteristics under heavily diluted and quite lean condition.

Sprak

Microwave Plasma-Assisted Ignition

The combustion under lean condition and the low flame temperature which is achieved by "Exhaust Gas Recirculation (EGR)" are required in recent gasoline engine in terms of environmental effects. However, it is quite difficult to achieve stable ignition under lean and high EGR rate and the new ignition technology should be developed. Our laboratory focuses on "Microwave plasma-assisted ignition" which improves the growth rate of flame kernel generated by spark discharge. The ignition characteristics are improved by this method and the operating range will be widened toward lean and diluted condition. Experimental and numerical researches on the effect of the microwave radiation parameters and the phenomena during ignition are carried out.

MW

The effect of microwave on ignition process. Ignition is achieved under microwave radiation condition (lower row) though the spark withou microwave are not able to ignite.

Numerical Analysis of Ignition Process

Numerical analysis of ignition process is carried out. The physical properties which are quite difficult to measure in experiment are estimated by numerical simulations and the effects of various parameters of ignition condition are researched. The phenomena in ignition process are quite peculiar and it is quite difficult to conduct the accurate numerical analysis by commercial simulation software. Therefore, we develop in-house codes focusing on ignition and try to reveal the details of ignition phenomena under various conditions.

Sprak

The simulated spark ignition (conducted by Assoc. prof. Nakaya)

Laser Ignition

Laser ignition is the one of the most promising future ignition technology. Laser ignition can set the ignition point freely and the electrodes which are the source of the heat loss and deteriorate the ignition characteristics are removed. Although this technique has a lot of advantages, the physical phenomena of laser ignition are still unknown. Therefore, the experimental researches are conducted to reveal the phenomena of the laser ignition and to improve ignition characteristics.

シュリーレン写真

Our laboratory focuses on "Close Multi-points Laser Breakdown Ignition" and the ignition process which starts at close multi-points is researched.

Experimental setup

実験装置全景

実験装置全景(稼働中)