Analysis On The Characteristics Of Exhaust Pressure Fluctuation And Influencing Factors Of 2 - Cylinder Supercharged Intercooled Diesel Engine

As the energy conservation and emissions reduction policy increasingly strict, lightweight and miniaturization is more and more attention by the governments of the engine, reducing engine displacement is one of main methods to lightweight, miniaturization. Two cylinder of high pressure common rail diesel engine is a energy-saving mini car diesel engines, compared with three cylinder, four cylinder engine, the cost advantage. Two cylinder diesel engine with 360°CA firing interval Angle, so will appear in the 720°CA work cycle of about 70° CA intake and exhaust slot Angle, turbine inlet pressure and compressor exit pressure fluctuations, turbine efficiency decline. Exhaust pressure pulsation, turbine blades, the blade to produce local high temperature, easy to cause the turbine blade fatigue damage, so the two cylinder pressure fluctuation characteristics of diesel engine exhaust pipes and influence factors were analyzed, and to improve the efficiency of the turbine, air intake efficiency and improve the efficiency of two cylinder turbocharged diesel engine, power performance and emission characteristics is of great significance.In a 2 cylinder turbocharged inter-cooled diesel engine exhaust pressure fluctuation in the bigger question,2 cylinder diesel engine a one-dimensional model is established and the exhaust manifold three-dimensional model, application of one-dimensional and three-dimensional coupling numerical simulation method, under different rotating speed of engine in a working cycle of the gas flow characteristics of the exhaust pipe, variation rule and influence factors of the exhaust pressure fluctuation are analyzed, numerical simulation for the internal flow field in turbine is calculated. The results show that turbine blade surface of fluid shear stress in inlet pressure maximum when the maximum shear stress was 1748.9 Pa, with minimum inlet pressure maximum shear stress was 1539.8 Pa, shear stress change 209.1 Pa, there is a larger shear stress wave, make larger shear stress, the vane of turbine blade fatigue damage caused by lower the efficiency of the turbine; Had a greater influence on the exhaust pressure fluctuations on the flow field in the turbine, change the exhaust pressure of the impact on the turbine blade is stronger, affect the service life of the turbine blades; Under full load conditions, the speed of 1000 r/min to 2200 r/min, the exhaust pressure wave intensity increased from 1.82 bar to 3.56 bar, turbine efficiency fluctuation intensity is reduced from 0.12 to 0.12; Speed of 2200 r/min to 3800 r/min, the intensity of the exhaust pressure fluctuations by 3.56 bar to 1.52 bar, turbine efficiency fluctuation intensity tends to a stable state of 0.02; Length and diameter of exhaust manifold and exhaust advance Angle has a significant influence on the low speed turbine efficiency.