Effect of Pilot Fuel Quantity on the Performance and Emission Characteristics of a Pre-Mixed CNG - Diesel Dual Fuel Mode Engine

Abstract

The serious environmental pollution and the energy crisis all over the world has caused for development of the lower pollution and lower energy consumption automobile to become major research goal. With huge back ground, Compressed Natural Gas (CNG) is projected as the best alternative fuel for the country like India. The properties of CNG make it an ideal fuel for direct use in spark ignition engines. Conversion of any existing spark ignition engine to operate on natural gas is relatively simple with available equipment. Many spark ignition engine vehicles are successfully operating in major cities of India with CNG fuel. However CNG cannot be used as a fuel in diesel engines with ease. Since the maximum engines at present run on diesel, it will be very much useful if a solution could be found to alter the existing diesel engine with minimum modifications to run on CNG. Several researchers could attempt to run diesel engines with CNG. In the process three methods were reported to be successful to use CNG as a fuel in diesel engines, they are (i) Spark ignited gas mode (ii) Direct injection of CNG in dual fuel mode and (iii) Premixed CNG dual fuel mode. In the present work a premixed dual fuel engine was developed which can perform well for the entire range of load and experiments are carried out by varying the pilot fuel amount and studied the effect of pilot fuel amount on engine performance and emissions characteristics and determined optimum fuel injection quantity for better performance and lower emissions.