“A New Generation of High Efficiency DI Gasoline Engines – Serious Competition for the DI Diesel Engine ?”

Authors

Dr. Dirk Andriesse, Dr. Franco Cazzolato, Dr. Aldo Marangoni, Dr. Aldo Oreggioni, Dr. Stefano Quinto, Fiat Powertrain Technologies – Arese / Turin - Italy

Year

2006

Summary

In the last decade, due to the breakthrough of the DI turbo diesel engine thanks to the Common Railtechnology, the gasoline engine has lost significantly in competitiveness as a power source for passenger cars. The market-share in the European market shrunk from 71% to 49% in the last 10 years. The main reasons for this are the poorer fuel efficiency of the gasoline engine and the increasing fuel prices reaching nowadays $75/barrel leading to much higher costs to drive the car compared to a diesel powered one. To improve the efficiency of the gasoline engine various approaches were undertaken and in the last decade both variable valve train systems and direct injection lean burn concepts were launched into the market on naturally aspirated engines but neither of those were able to halt the advance of the diesel engine. This was not due only to the insufficient improvements in fuel economy or the high costs of those technologies, but also to the fact that these engines did not have the same appeal to the customer because of the missing low end torque and subsequently lack of fun to drive, this being a point of excellence of the diesel. The following proposed new turbocharged gasoline engine, with double continuous cam phasers and direct injection, offers a very good base for significant improvements of both fuel economy and fun to drive of the spark ignited engine. The combination of these three available technologies gives important supplementary benefits through their mutual interaction, and this can give a real boost to the attractiveness of the future gasoline engine. As the single ingredients are already in series production the cost increase of the gasoline engine, as well as the development risk, are relatively low. This makes this new high efficiency gasoline engine a very powerful contender to interrupt the current hegemony of the diesel engine in the medium-high displacement class engines.

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