Effect Of Fuel Injection Timing And Hydrogen Injection Timing On The Performance Of Hydrogen Blended Gasoline Engines

Against the backdrop of an energy crisis,countries are actively seeking new energy alternatives to reduce their dependence on fossil fuels such as oil.At the same time,increasing environmental pressures have prompted many countries to take measures to restrict the production and sale of fuel-powered vehicles in order to accelerate the transition towards new energy vehicles.Hydrogen-doped internal combustion engines,as a new energy technology,have broad development space and application prospects under these two trends.The research object of this article is a hydrogen-injected internal combustion engine with fuel injection into the intake manifold.Based on a full experimental design,grey correlation analysis combined with particle swarm optimization algorithm was used to optimize the hydrogen injection timing and fuel injection timing.Firstly,a full experimental design scheme was formulated,and the performance and emissions of the hydrogen-injected internal combustion engine with different fuel injection timing and hydrogen injection timing under different working conditions were comprehensively compared and analyzed,and the optimization intervals for both were determined respectively.Secondly,the grey correlation analysis method was used to standardize multiple indicators of the hydrogen-injected internal combustion engine to eliminate dimensional differences between different indicators,and calculate the grey correlation degree of the data.Based on the different emphasis on power,economy,and emissions under different working conditions,the correlation between each indicator and the decision target was obtained.Finally,the indicators were ranked to determine their degree of influence and relative importance on the decision target,and the weights were calculated for each working condition.Based on this,the particle swarm optimization algorithm was used to calculate the optimal combination of hydrogen injection timing and fuel injection timing for the hydrogen-injected internal combustion engine under different working conditions.The study found that when the speed of a hydrogen-doped internal combustion engine falls below 1500 rpm it tends easily experience air intake blockage phenomenon which can be alleviated by early-stage hydrogen injection instead.In addition,both hydrogen injection timing and fuel injection timing nonlinearly affect combustion characteristics of a hydrogen-doped internal combustion engine;changes in them can increase peak temperature inside cylinders along with pressure levels while improving indicated thermal efficiency but at cost of increased nitrogen oxides(NO)emissions along with hydrocarbon(HC)emissions too;delaying fuel injection timings effectively reduces NOx & HC emissions though.To improve quality of IC engine’s combustion,enhance its power and indicated thermal efficiency,hydrogen injection and fuel injection should be advanced appropriately.Compared with genetic algorithms,PSO algorithm has faster convergence speed(gradually approaching stability after about 30iterations)and fewer parameter adjustments during iterations.Analysis of MAP charts for optimal hydrogen injection timing and fuel injection timing under different operating conditions shows that as the engine speed increases,the optimal hydrogen injection timing needs to be advanced with an increasing rate while the optimal fuel injection timing also needs to be advanced but at a slightly decreasing rate;in addition,as load increases both timings need to advance so as to improve combustion efficiency while reducing emissions.