Research On Approach To Realize Quasi-isothermal Expand Of Air-powered Engine

The development of car is restricted by energy and environment. All countries establish more and more strict let law in order to solve problems. Besides, there are some new technologies; one of these is the technology of air-powered engine. But there is one problem that the efficiency of air-powered engine is low, of course, references mention some methods to improve the performance of air-powered engine. The paper is about quasi-isothermal expand.Funded by the Natural Science of Foundation of China-Ford Found-"Research on air-powered vehicle engine"(No.021101759), and also funded by the National Research Foundation for the Doctoral Program of Higher Education of China-"The Theoretical and Experimental Research for The Liquid Nitrogen Engine"(No.20020335079). The work has been carried out can be summarized as follows:Firstly, based on heat transfer theory, obtains the quantity of heat to realize isothermal expansion by calculation in air-powered engine, analyses main factors to affect the quantity of heat transfer. Competes a simulation in Matlab, draws a sketch map of temperature in cylinder with fins as crank rotating.Secondly, on the basis of the special requirement, model a cylinder with fins modeling by UG;Thirdly, based on the relation of quantity of heat between the gas in cylinder to expand and air-powered engine can transfer; draw a conclusion between acreage of heat transfer and difference of temperature. Under the circumstances of 27℃, it will need a bigger acreage of heat transfer, and the cylinder with fins will be not practical; Under the circumstances of a higher temperature, it will be practical, but considering the source of heat, it is not practical. It is not practical to use cylinder with fins.Fourthly, combined with the characters of air-powered engine, gets a important formula under the circumstances of isothermal, isobaric and equal volume expansion. Then confirm that the method to reheat and the number of cylinders in air-powered engine;Fifthly, analyses the energy distributing relation between single-step expansion and multi-steps expansion on the basis of sketch map of multi-steps regenerate cycle with equal volume. And then confirm how to reheat with equal volume;Sixthly, calculates the acreage of multi-steps expansion of air-powered engine, and discusses the layout of heat exchanger.