Improvements to direct-injection spark ignition engines by advanced technologies

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The latest direct-injection spark ignition engines possess a great flexibility with respect to injection timing and the use of multiple injection strategies. Other technologies can also be beneficial to the engine such as improvement to the ignition process, the implementation of stratified EGR (exhaust gas recirculation), or the usage of biofuels that offer reduced greenhouse gas emissions when the fuel life-cycle is considered. In this research program, it is proposed to study the impact of multiple injection strategy requirements as a function of different biofuels as well as to characterize the resulting mixture ignition requirements. Moreover, a new stratified EGR system proposed by the applicant will be developed and tested as a means to reduce fuel consumption and pollutant emissions. Thus, experiments will be conducted using spark ignition engines and will involve multiple injection of biofuels, parametric study of the spark discharge characteristics and the implementation of a stratified EGR. To gain an understanding of the phenomena at play and to help explaining the observed behaviour in the engine, fuel spray experiments and simulations using a Large Eddy Simulations (LES) approach will be pursued. The experiments will allow isolating different parameters and to see its impact on the mixture formation process through advance optical diagnostics. LES of the fuel spray will include improvement to droplet collision model. Moreover, a spark discharge LES model will be developed including flame and dissociation kinetics to quantify the impact of spark ignition characteristics under stratified EGR and flowing mixture. Both models allow meeting long-term goal of developing advanced modelling capability to that are used in engine design while also offering a rational explanation.on for the observed results in engine. The impact of the proposed research program could be far-reaching. For example, by linking fuel properties and engine performance, the research program could help identify “must-have” biofuel properties or potential biofuels. The latter could prove helpful with the next generation of renewable fuels that will benefit the Canadian biofuel industry. Moreover, biofuels have the potential to reduce GHG and Canada has a high biomass availability. By improving DISI engines through advanced injection strategy, advanced EGR and biofuels, as proposed herein, will also help reaching Canada's Clean Fuel standard to reduce GHG emissions by 30 Mt/year by 2030.