Study on dynamic response characteristics and optimisation of common rail injectors

High-pressure common rail fuel injection technology diesel engine control technology core, and common rail injector are the soul of the technology. During cold start or high-speed operation of a diesel engine, the combustion chamber is prone to uneven oxygen supply and temperature difference, which leads to the phenomenon of "black smoke". Through simulation software and response surface optimization method, the influence of injector structural parameters on the dynamic response characteristics is investigated, in order to improve the response characteristics of the injector, thereby enhancing the quality of in-cylinder combustion and reducing pollutant emissions. The study showed that increasing the control valve lift shortened the opening delay but increased the closing delay; increasing the control piston diameter and fuel inlet passage diameter increased the opening delay and shortened the closing delay; and increasing the fuel outlet passage diameter decreased the opening delay. The control piston diameter has the greatest effect on opening and closing delays, while the fuel outlet passage diameter has almost no effect on closing delays. After optimization, the opening delay is reduced by 3.12–4.79 % and the closing delay is reduced by 17.19–19.01 % at six different orbital pressures.