Ethanol Direct Injection on Turbocharged SI Engines - Potential and Challenges 2007-01-1408
In the past application of alternative fuels was mostly concentrated to special markets - e.g. for ethanol and ethanol blends Brazil or Sweden. Now an increasing sensitivity towards dependency on crude oil significantly enhances the interest in alternative fuels. With spark ignited engines, ethanol and gasoline / ethanol blends are the most promising alternative fuels - besides CNG. The high octane number of ethanol and the resulting excellent knock performance gives significant benefits, especially with highly boosted engines.
However, the evaporation characteristics of ethanol result in challenges regarding cold start and oil dilution with GDI application.
This paper deals with investigations on a turbocharged DI engine operated on ethanol fuel in order to improve challenges of ethanol fuel, such as oil dilution and cold start.
Cold start can be improved by injecting fuel late in the compression stroke (high pressure start) based on a refined engine design and operation strategies.
Oil dilution has to be deeply investigated on a transparent engine in order to optimize charge motion, spray pattern and penetration.
The paper describes the systematic approach of optimizing a DI /TCI spark ignition engine for ethanol fuel with respect to cold start potential and avoiding oil dilution especially during high load operation.