The Simulation Research On The Working Process Of The Double-Disk Nutating Diesel Engine

With the development of society, the increasing number of car inventory in most countries, the severer air pollution and more and more energy depletion have arisen attention to the fuel economy of engine. To improve the economy and emission performance, it’s difficult to make great break through energy consumer and emission of tradition engines. Therefore, the article put forward a new engine—diesel engine with double wobble-plate. The one-dimensional performance of the new engine has been computed, meanwhile, parameters of pressure ratio, expansion ratio, combustion starting angle, combustion duration, length and dimension of intake and outtake tubes have been analyzed to examine the influence to the engine performance.It can’t be calculated because of the structure and movement difference between tradition and new engines, therefore, according to the double wobble-plate engine’s feature, this article transfers the new type engine to the tradition equivalent engine. With the base of the working process calculation of engine and the computation theory of AVL BOOST software, numerical simulation and optimal computation have been made on the equivalent engine through AVL BOOST. Through the established model, the following items have been studied:(1) What’s the laws for performance influence of equivalent engine when the pressure ratio of the compressor separately are19、21、23、25、27、29and31,show that the maximum combustion pressure increases and the working process of the diesel engine becomes more and more brutal when the pressure gas ratio increases.(2) What’s the laws for performance influence of equivalent engine when the expansion ratio separately are14.5、15、15.5、16、16.5、17and17.5, show that the engine power and economy are improved, but the mechanical load is increased when the expansion ratio increases.(3) What’s the laws for performance influence of equivalent engine when the combustion starting angle separately are193.5°CA、194°CA、194.5°CA、195°CA、195.5°CA、196°CAand196.5°CA, show that the engine power is improved and the effectively fuel consumption rate reduced when the combustion starting angle is reduced in the case of a certain speed, but too small combustion starting angle causes that the maximum combustion temperature is too high, the discharge characteristics deteriorate.(4) What’s the laws for performance influence of equivalent engine when the combustion duration separately are31.5°CA,34.5°CA.37.5°CA、40.5°CA、43.5°CA、46.5°CA and49.5°CA, show that the maximum combustion temperature is lowered, the engine combustion process become soft when the combustion duration increases, but the combustion duration duration is too large so that thermal efficiency decreased; the combustion duration is too small so that mechanical load and thermal load increases.(5) How to make matching optimize between combustion starting angle and combustion duration.(6) What’s the laws for performance influence with different length and dimension of intake and exhaust show that the engine power increase, the economy and the coefficient of charge reduce when the length of the intake manifold increase. The engine power, the economy and the coefficient of charge increase when the length of the intake diameter increase. With the increase in the intake pipe length and diameter, the impact on these performance gradually decreases. With the increase in the length of the exhaust pipe, the power of the diesel engine increases in the low-speed, it decreases in the high speed. Torque of the engine is increased with the increase in the length of the exhaust pipe, smaller changes. With the increase in the length of the exhaust pipe, the economy of the diesel engine are reduced. With the increase in the diameter of the exhaust pipe, the engine power and economy are improved, and affect on the charge coefficient can negligible.Ultimately, numerical simulations and comparisons have been made between the tradition engines and the later equivalent engines with structure parameter optimization. The computed result shows that the dynamic, economic and emission property of improved equivalent engine has improved in varying degrees, which provide theoretical basis for further double wobble-plate engine design.