Impacts of Injection and Ambient Temperatures on Direct Water Injection in Internal Combustion Engin

• 作 者: WU Jingtao KANG Zhe ZHANG Zhehao LI Zhilong WU Zhijun
• 机 构: School of Automotive Studies,Tongji University
• 出 处: 2018中国汽车工程学会年会
• 发表日期: 2018年9期
• 关键词: internal combustion engine water injection injection temperature ambient tempera

　　This paper focuses on the impacts of injection and ambient temperatures on direct water injection in internal combustion enginesthrough experimental and numerical methods.Firstly,the study was carried out by utilizing Schlieren method combined with a high-speed camera for simultaneous liquid-gas diagnoses.Water was directly injected into a constant volume vessel which is capable of providing stable boundaries.A self-established Matlab program wasused for the calculation of spray tip penetration and cone angle.For thefurther extension of boundary conditions,a numerical model was established and calibrated in AVL-Fire for the thorough analysis of injection characteristics.Both experimental and numerical results indicate that injection and ambient temperatures show different effects on spray tip penetration.The increase in injection temperature leads to shorter spray tip penetration,while the spray tip penetration rises with the increase inambient temperature.However,the increase in injection and ambient temperatures can both decline spray cone angle.Moreover,the simulation results also suggest that heat conduction is a main factor in boosting evaporation process under top dead center conditions.When internal energy of water parcels surges,these parcels evaporate immediately.These results are helpful and crucial in internal combustion engines equipped with direct water injection technology.