Laser Spark Ignition in lean burn CNG Engine

Abstract

The CNG Engines play a dominant role in transportation and energy production. The CNG engine is an environment-friendly engine, which causes drastic reduction in emission to the environment by using CNG as a fuel in IC engine. Spark plugs work by sending small; high-voltage electrical sparks across a gap between two metal electrodes Spark plugs can ignite leaner fuel mixtures, but only by increasing spark energy. Unfortunately spark plug cannot ignite leaner air-fuel mixture for long time it produce exhaust emission as well as reduce the efficiency of engine. ON the other hand, Laser ignition system of engines represents a more and more realistic alternative to traditional spark plug or high-frequency ignition approaches. Its ability to ignite extremely lean mixtures of fuel and air allows one to efficiently reduce the NOX concentrations in the exhaust gases, which are associated with potential long-lived ignition components. In this project, an overview of the laser parameters necessary to ignite the most common lean burn air-fuel mixtures for CNG engines is presented. Furthermore, a novel approach for multipoint laser ignition is discussed as a viable path for speeding up the long combustion durations of lean mixtures. Finally, an innovative approach to compact, robust, and relatively cheap laser ignition is described, which involves miniature laser systems. The passively Q-switched laser head is ideally mounted on each cylinder, while the optical pump should be located far away. Ignition energies in the range of slightly more than 1mj per pulse are realized with the involvement of perfect optical focusing.