| Facing increasingly stringent emissions regulations, electronic control high pressure common rail system has became an inevitable trend using in marine diesel engine. Electronic control injector is a core component of common rail fuel system. It’s action response speed determines whether the fuel injector can achieve flexible injection laws like multiple-injection;cycle fuel injection quantity and its control accuracy are key factors for fuel injector to match with diesel engine successfully and make the system work stably. Researching on injection characteristics of electronic control injector for small bore low-speed diesel engine have important theoretical significance and engineering applications value for the design and optimizing on the injector.The working principle of small bore low-speed diesel engine fuel system was analyzed in-depth in this paper. According to its characteristics, concept drawing of the electronic control injector was designed. Numerical simulation model was established in AMESim environment, and the modeling method was calibrated. By comparing and analyzing the relevant data, it showed that the modeling method is accurate and reliable, and the model can meet performance requirements of small bore low-speed diesel engine.Combining with design requirements, performances of electronic control injector were analyzed in-depth with the numerical simulation model. In the typical condition, action response of fuel injector was studied, the non-linear control region of cycle fuel injection quantity and influence of different characteristic parameters on action response were summed up. It showed that: control valve rod maximum lift, moving parts mass and residual gap had great impact on action response of control valve and needle valve; control piston diameter,control chamber inlet hole diameter, outlet hole diameter, pipe diameter after control chamber,needle valve spring preload force and nozzle diameter were the key parameters of needle valve action response.In the whole working conditions, influences of different characteristic parameters on cycle fuel injection quantity were researched, and quantization indicators of every parameter’s influence factor and the trend of the percentage with crankshaft speed and fuel injection pulse width were obtained. In the typical condition, the influence mechanism of pilot injection to main fuel injection quantity was studied. It showed that the pressure wave caused by pilot injection is the fundamental reason what leads to fluctuation of main injection quantity with dwell time. And the key parameters which affect the fluctuation law of main injection quantity with dwell time were obtained. |
