Trends in Gasoline Engines Technology
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Publication date: 2005-05-01
Combustion Engines 2005,121(2)
The development of vehicle powertrains is increasingly challenged by emission legislation and by the end-users’ fueleconomy demands. In order to meet these requirements it is necessary to continuously improve existing powertrains and to develop totally new generations of engines. For Gasoline engines in passenger cars the most important task is to improve fuel efficiency. Therefore, a big variety of different technologies potentially can be applied. The system range from simple variable charge motion and low cost variable valve timing devices up to highly sophisticated systems like fully variable valve actuation systems and also combustion with auto ignition (HCCI). Direct Gasoline Injection systems of Generation 1 (wall guided systems) and even more the systems of Generation 2 (spray guided systems) improve fuel efficiency, but the significant oncosts for NOx exhaust aftertreatment have to be taken into consideration. Due to its full load benefits homogeneous DGI is a preferred solution for high performance engines as well as in combination with turbocharging for downsizing/downrating concepts. The combination of turbocharging, direct injection and cam phase shifter has proven to be a highly attractive package combining good fuel economy with fun to drive. The different gasoline engines technologies will have to be applied according to the specific needs of their application and brand specific requirements. Even keeping high performance characteristics, fuel consumption will be reduced continuously and future legislative limits can be met. However, system complexity and cost will increase.