Influence of Injection Timing on the Performance of Dual Fuel Compression Ignition Engine with Exhaust Gas Recirculation

–Fast depletion of fossil fuels demands an urgent need to carryout research to find viable alternative fuels such as Hydrogen, LPG and CNG. The gaseous hydrocarbons seem to be best immediate option presently available[1]. The remarkable feature of gaseous fuels are the absence of mineral impurities, the consistency in quality and the convenience and efficient in use. LPG is used widely as a co-fuel with diesel since it is possible to obtain high energy storage density. For a diesel engine, fuel injection timing is a major parameter that affects the combustion and exhaust emissions. The state of air into which the fuel injected changes as the injection timing is varied, and thus ignition delay will vary. Hence, injection timing variation has a strong effect on the performance and exhaust emissions, especially on the NOx emissions, because of the changing of the maximum temperature in the engine cylinder. The Exhaust Gas Recirculation (EGR) system is designed to reduce the amount of Oxides of Nitrogen (NOx) created by the engine during operating periods that usually result in high combustion temperatures. The EGR system reduces NOx production by recirculating small amounts of exhaust gases into the intake manifold where it mixes with the incoming air. By the proper mixing with the air, the peak combustion temperatures and pressures are reduced, which in turn reduces NOx emission. The present work is an experimental investigation on 4 stroke CI engine in dual fuel mode with diesel as injected fuel and LPG as inducted fuel. The engine is run under different operating conditions, and in each case the optimum combination of inducted to injected fuel energy proportions are determined for best efficiency. At each operating condition the exhaust smoke level, NOx, CO,HC, exhaust gas temperature and other performance parameters are obtained.