Effect Of Pipe Hydrogen Injection On Lean Combustion Of Direct Injection Gasoline Engine

The internal combustion engine technology is powered by gasoline,diesel,natural gas and other fuels.These energy consumptions depend on one-time energy oil,and exhaust emissions cannot meet environmentally friendly construction requirements.Under the current policy of vigorously supporting new energy vehicles,hydrogen can be used as a new type of vehicle energy.Based on the in-cylinder direct injection gasoline engine,the partial combustion gas is too rich,the flame is easy to extinguish the propagation to the lean mixture,and the NOx conversion rate is low.The distribution of the mixture of the lean combustion of the GDI gasoline engine under different hydrogen injection volumes of the inlet is studied.Combustion effects.In this paper,a three-dimensional model of inlet hydrogen injection GDI gasoline engine is established.Based on the basic law of energy conservation of chemical reaction fluid mechanics in FIRE software,the hydrogen injection device is added to the inlet.Based on FIRE simulation,the volume fraction of mixed hydrogen in inlet is 0,4%.8%,12%,16% and 20%,the in-cylinder mixture is formed at each rotating speed,the combustion process is adjusted,and the excess air coefficient is 2.0and 2.25 when the fuel injection is adjusted.The optimal hydrogen mixing volume at different rotating speeds and the abnormal combustion correlation under different hydrogen mixing rates were analyzed.The results show that the range of turbulent kinetic energy and mixture concentration is small when the hydrogen is mixed at 4% volume,and the degree of unevenness is increased when the volume of hydrogen is too large.The indicated power decreases first and then decreases as the volume of hydrogen increases,and the indicated power is relatively high at 4% volume.Mainly due to the partial increase of the hydrogen injection amount in the intake port,the uniformity of the in-cylinder mixture is weakened,and the functional force is reduced.It indicates that the thermal efficiency is most obvious under the 4% volume of hydrogen mixing,and the flame spreads rapidly under a more uniform mixture,reducing heat transfer loss and improving fuel economy.4% volume of small and medium-speed rotational hydrogen is an ideal amount of hydrogen.At high rotation speeds,the concentration range of the mixture at 8% volume and 12% volume is small,and the indicated power is also high.Hydrogen promotes the full combustion of the mixture,and hydrogen participates in combustion,releasing more heat after combustion.Functional enhancement in unit time.When the volume of hydrogen mixed is 8%,the indicated thermal efficiencyreaches a maximum value,and when the amount of hydrogen mixed is too large,it indicates that the thermal efficiency increases slowly or even decreases.The amount of hydrogen actually flowing into the cylinder is limited,and the effect on the flame propagation is limited,and the functional force is reduced.Mixing 8% by volume and12% by volume at high rotational speeds is an ideal amount of hydrogen mixing.The amount of NO produced in 4% by volume and 8% by volume of hydrogen is relatively low.Under this volume,hydrogen gasoline has a lower combustion temperature than other volumes and has a positive effect on controlling NO concentration.In terms of abnormal combustion correlation,the peak temperature and discharge temperature of the combustion of more than 16% of the volume of the mixed hydrogen are higher,increasing the possibility of pre-ignition.At medium and small speeds,after the amount of hydrogen mixed exceeds 12%,the amount of residual hydrogen in the inlet increases significantly,increasing the possibility of tempering.