Effect of combustion system parameters on engine performance. The oil feed advance angle and injection pressure test results show that the optimal fuel supply advance angle (CABTDC) of dimethyl ether during operation is: 19° in the calibration condition and 15° in the low rotation speed. This is 6°~9° less than the optimal fuel feed advance angle (25°) when the diesel engine is in operation, and the highest thermal efficiency when the dimethyl ether injection pressure is 15 MPa (lower than the diesel injection pressure of 18 MPa). This is due to the higher cetane number, lower auto-ignition temperature, and better atomization performance of dimethyl ether compared to diesel. The plunger diameter was tested for the effects of three plungers with diameters of 8.5mm, 9.0mm and 9.5mm on the thermal efficiency of the engine. The thermal efficiency η of the different diameter plungers varies with the mean effective pressure P, and it can be seen that the thermal efficiency of the engine increases as the plunger diameter increases. This is due to the fact that the low calorific value and liquid density of dimethyl ether are only 64.7% and 80% of that of diesel. The increased oil supply per cycle requires an increase in the plunger diameter to shorten the injection duration to improve engine performance.
The shape of the nozzle and its depth into the cylinder tested the effect of five different types of nozzles on the thermal efficiency of the engine. Among them, the 5×0.32mm nozzle is the best and the highest thermal efficiency is obtained. Compared with the 4×0.30mm nozzle used in the original machine, the number of orifices increases, the diameter increases, and the total flow area increases. This structure of the nozzle can be better with the low intake swirl ratio (the best intake swirl ratio when burning dimethyl ether is 1.4 to 1.8, much lower than the original turbine eddy current ratio 2.3) and a large circulation for Matching the oil amount is beneficial to the formation and combustion of dimethyl ether mixture. Studies have shown that when using dimethyl ether, the optimum length of the nozzle into the cylinder is 5mm, which is longer than 3mm when using diesel fuel. This is due to the better evaporation and atomization performance of dimethyl ether. The spray cone angle formed after the fuel is injected into the cylinder is large. To prevent the liquid fuel from hitting the bottom surface of the cylinder head and causing combustion deterioration, the length of the nozzle into the cylinder must be Increase.
Showerhead Glass Water Pipe,Arm Tree Perc Glass Bong,Freezable Coil Glass Pipe,Glass Water Pipe For Smoking
HEBEI DINGSHUO GLASSWARE CO.,LTD , https://www.dsglasspipe.com