| As a higher thermal efficiency power machine, diesel engine has been applied abroad to traffic transport and used as agriculture machine and engineering machine, which has gained marked society benefits. It is well known that diesel engine brings advantage to people, at the same time, also brings huge pressure to entironment for its NOx and PM emissions. With the stricter of emission rules and the pursuing of high heat release rate, large numbers of investigation are carrying out on diesel engine structure factors, fuel injection law, the shape of combustion chamber, EGR and so on, and some of which improved the performance of diesel engine. Above all, fuel injection time is one of main factors which effect diesel engine performance notablely. There exists an optimal fuel injection time (the optimal fuel injection advance angle), which is different with the different operating conditions. To realize high pressure, common rail electric control fuel injection system on the diesel engine is inevitable direction. Nowadays, for technical juvenility and higher cost of electric control fuel injection system of high-power diesel engine, the application of this system is less. Nowadays, most application of fuel pump on the high-power diesel engine is mechanical fuel pump, so it has practical meaning to investigate the effect of fuel injection time on diesel engine performance. It is difficult to accurately adjust and control fuel injection time on mechanical fuel pump, and in practice fuel injection advance angle is ensured by static fuel supply advance angle. For the existence of pressure wave in fuel transportation pipe, there is a delay between the beginning of fuel supply and the beginning of fuel injection, so it is difficult to accurately adjust fuel injection advance angle by adjusting static fuel supply advance angle. But for each operating condition, the effect of above-mentioned factor usually is determinate. So for the same operating condition, the effect of static fuel supply angle and that of fuel injection advance angle on diesel engine combustion process are accordant. It has practical meaning to investigate the effect of static fuel supply advance angle on diesel engine performance. The effect of static fuel supply advance angle on diesel engine performance was investigated, and the tested engine was CA6DE1-21K turbocharged and intercooled diesel engine. To fully investigate the effect law of static fuel supply advance angle, the speeds selected in this investigation were 1000r/min, 1500r/min, 2500r/min, and the loads selected were 50%, 75% and 100% full load under each speed operating condition, and the static fuel supply advance angles were 6, 10 and 14oCA. The cylinder pressure was measured by combustion analyzer DS9100, and the start of ignition, ignition delay period, the maximum of pressure rise rate,emissions and so on,was analyzed by combustion analysis software DS0928. The tested results showed that with the increase of fuel injection time under the same operating conditions, the start of ignition advanced; ignition delay period became shorter; the maximum of combustion pressure and the maximum of pressure rise rate increased; the smoke emissions decreased appreciably and the NOx emissions increased deeply. To meet the stricter emission rule in the future, just investigating the effects of some aggregate factors on macroscopical performance of engine is not enough, and in-depth investigating the law of each effect factor on diesel combustion process is imperative under the situation. With the development of computer and computation science, more researchers are engaged in computational simulation of engine combustion process including: air intake process simulation, spray simulation, combustion simulation and so on. There are many advantages of numerical simulation by computational fluid dynamic (CFD) software such as low cost, short period and can show some information which can't be provided by testing. The distributing of concentration, velocity, pressure and temperature in the computational area can be got by computational simulation in detail. The combustion process of CA6DE1-21K diesel engine was simulated with a commercial computational fluid dynamics software STAR-CD. In this CFD software fuel injection law should be given beforehand. For the importance of fuel injection law to combustion process, it was measured on the test bench. The measured results showed that fuel injection velocity was fluctuant, the reason of which was there existed pressure wave in the fuel transportation pipe. With the increasing of load, fuel delivery per cycle per cylinder increased; the maximum fuel injection velocity increased and fuel injection period prolonged. Geometry modeling was aiming at CA6DE1-21K diesel engine. Firstly, using reverse engineering special automatic software GEOMAGIC, I have finished creating surface on point cloud of sand mould of intake port. Secondly, by Pro/ENGIEER finished creating intake port entity inside the surface, then assembled the final model with combustion chamber and exhaust port. With the common tetrahedron/polyhedron automatic gridding maker PRO-AM, the gridding of the intake port, exhaust port and chamber can be generated automatically. With the engine special moving gridding maker ES-ICE, the moving gridding was made with mapping method. Finally, usable computational gridding was finished by associating the intake port, exhaust port and chamber gridding with moving gridding. The operating conditions of 1000r/min were simulated with STAR-CD software, and the distribution of fuel-air ratio and temperature were analyzed in detail under 1000r/min operating conditions. At the same time, the injection process and velocity distribution of fuel injection was analyzed briefly, and the results agreed with the test results acceptablely. Something found from computational simulation are as follows: 1. The indicated diagram and heat release rate law resulting from simulation after adjusting some parameters agreed with the data from the testing, which...
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