report on laser ignition system for ic engine

seminar report on laser ignition system pdf

Abstract

Laser ignition is an alternative method for igniting compressed gaseous mixture of fuel and air. The method is based on laser devices that produce short but powerful flashes regardless of the pressure in the combustion chamber. Usually, high voltage spark plugs are good enough for automotive use, as the typical compression ratio of an otto cycle internal combustion engine is around 10:1 and in some rare cases reach 14:1. However, fuels such as natural gas or methanol can withstand high compression without self ignition. This allows higher compression ratios, because it is economically reasonable, as the fuel efficiency of such engines is high. Using high compression ratio and high pressure requires special spark plugs that are expensive and their electrodes still wear out. Thus, even expensive laser ignition systems could be economical, because they would last longer.

Introduction

Summary form only given. This work focuses on the development of a compact, robust and reliable Nd:YAG solid-state laser. A diagram for the pulse energy in dependence of the reflectivity of the output mirror and the initial transmission of the absorber, as well as the analysis of inject optics and optimum pump duration is established. The highest pulse energies was reached by a reflectivity around 45% and an initial transmission of 40%. Moreover, the pump duration should be in the order of the fluorescence lifetime of the laser active medium, otherwise the laser system becomes more unstable the longer the pump pulse is. Applying this configuration, pulse energies up to 6 mJ and pulse durations under 1.5 ns were reached.