A type of STL-injector (Self temperature limit) is proposed to reduce consumption and emissions of biodiesel. The STL-injector is expected to raise fuel temperature quickly during cold-start, thus spray quality and combustion efficiency will be improved, fuel consumption and emissions are subsequently reduced. A model of STL-injector was built after considering electromechanical coupling and Fluid-structure interaction. A transient simulation research was conducted with dynamic grid technology. The results show that STL-injector may quickly raise temperature of biodiesel to 352K from 300K. The combination of biodiesel and STL-injector may be beneficial to environment and energy-saving.