Abstract
Natural gas is one of the most promising alternative fuels because of its clean burning characteristic, lower CO2 emissions and plentiful availability. However, the disadvantages of natural gas vehicles include short driving ranges and poor engine performance. This article describes the results of applying direct injection engine techniques to a natural gas engine. The results indicate that natural gas direct injection is suitable for stratified combustion and improves fuel economy by improving stratified mixture formation. Moreover, full load engine performance can be improved because direct gas injection during the compression stroke increases the air induction efficiency.
Keywords:compressed natural gas, stratified charge engine, combustion, direct injection, mixture formation