柴油机进气火焰预热系统着火临界温度的研究

Installing flame preheating system at the intake manifold is an effective method for diesel engines to improve the cold-starting performance. Based on a self-built test platform of the intake flame preheating system, the influence of intake flow rate and the direction of fuel injection on the critical ignition temperature was experimentally studied. The results show that the critical ignition temperature decreases first and then increases with the increase of the angle between the direction of fuel injection and the direction of air flow, and the flame area decreases first and then increases with the increase of the angle. At the angle of 90°, the critical ignition temperature is the lowest and the flame area is the largest. In the preheating stage of the intake flame preheating system, the intake flame manifold burner head temperature has a negative linear relationship with the intake flow rate. The larger the intake flow rate is, the earlier the intake flame manifold burner head temperature reaches stable. With the increase of intake flow rate, the critical ignition temperature decreases first and then increases and the optimal intake flow rate is about 400 kg/h. In addition, it is found that there is an upper limit for the studied intake flame preheating system to improve the intake air temperature by only changing the intake flow rate.