A Downsized, Turbocharged Natural Gas SI Engine - Including Hybridization - For Minimized CO ₂ Emissions

To demonstrate the potential of a CO₂-minimized propulsion concept a study of a natural-gas, micro-hybrid powertrain was carried out. The basis was built by experimental investigations of a turbocharged 1.0-l, 3-cylinder engine operated at stoichiometric and lean air/fuel ratio with EGR and an optimized combustion strategy. With the results of this study a still existing model for micro-hybrid vehicles was filled and the CO₂ emissions for several concepts were calculated. It could be shown that CO₂ improvements of 30 to 40% for the IC engine and up to 50% for the complete micro-hybrid propulsion system accompanied with better driveability are possible.