Laser Ignition Technology for Gaseous Fuelled Automotive Engines

Abstract

Most SI engine globally use conventional electric spark plug as an ignition source. Electric spark plugs have limitations in achieving higher efficiency and reducing emissions from gaseous fuelled automotive engine. In contrast to conventional electrical spark plugs, laser spark plugs are apt for use at higher in-cylinder pressures. Laser Ignition technology is capable of igniting leaner fuel-air mixture, which cannot be successfully ignited by conventional spark plugs. Laser ignition has proven its worth in defence and rocketry industry by replacing traditional spark ignition systems globally. Laser ignited combustion can be controlled by only few critical parameters, which makes it useful for implementation in variety of practical applications. Controlled combustion using laser plasma which requires minor engine hardware modifications is the key to implement it for variety of applications. Laser pulse generated plasma at the focal point, which is much more intense than conventional electrical spark plasma, can successfully ignite lean fuel-air mixtures. Main advantages of laser ignition technology include the possibility of igniting leaner fuel-air mixtures and flexibility to freely choose location of the igniting plasma. These interventions lead to lower NOx emissions, increased efficiency while avoids quenching effects due to electrodes, reduced electrode wear and consequently increased the lifetime of the electrodes. Laser ignition can be used for multi-cylinder engine by employing fiber optics and a single laser source. This chapter reviews laser ignition of gaseous fuel-air mixture as well as technology adaptation for implementation of laser ignition in automotive sector.