Direct Injection of Variable Gasoline/Methanol Mixtures: Injection and Spray Characteristics 2001-01-0966

The injection rate modulation and the spray characteristics are determining factors for the quality of mixture formation when applying GDI. Their variation with load and speed is a basic criterion for the adaptability of a type of injection system to an engine with known requirements. The increased interest for the utilization of regenerative fuels - such as methanol obtained from biomass - as well as the success of previous utilization scenarios of variable gasoline/methanol mixture using manifold injection formed the base of the present analysis: the paper describes the results concerning injection performances and spray characteristics when using gasoline/methanol mixtures with different ratios in a direct injection system with high pressure modulation. The results are compared for different parameters of the injection systems as follows: injection volume, injector opening pressure, needle lift, pintle/seat geometry. The injection performance and the time-related spray characteristics using a laser sheet technique were analysed for different gasoline/methanol ratios. The influence of mixture content on the injection parameters results as moderate. This is a valid argument for modeling and optimization of the internal mixture formation process using direct injection of gasoline/methanol mixtures.