Numerical Simulation Analysis And Research On Motorcycle Engine

There are two main methods for motorcycle development in domestic market, one is the copy and the other is the trial. With the international and national increasing strict protection of the intelligence, the copy method is declining while the trial method needs a great deal of time and cost. Numerical simulation, a complete new technology for the development of R&D motorcycles, is now becoming more and more popular on the bases of plenty of laboratory data cumulated from the domestic motorcycle development over two decades, and with the high development of computer's software and hardware and their popularity and application in engineering field. This new method, which will not be affected by the limits of trial environment and conditions, can be managed in a more efficient way, that is, has an access of making the design comparison between many optional proposals during the prophase period and select the best one; and it also has the advantage in terms of information which cannot be offered by the trial institute with less cost and time.It introduced two kinds of applications of numerical simulation technology in motorcycle engine development. One is numerical simulation for JH125 improved engine performance in BOOST and the other is numerical simulation for JL069 intake port flow in FIRE.The main works in this paper are as follows:1) The performance numerical simulation of JH125 improved engine in BOOST.① The numerical simulation model was constructed for the engine performance according to structure of JL069 engine.② It adopted right combustion model, transfer heat model and gas exchange model. The parameters of different elements were also inputted.③ The influence of timing system and intake system on JL069 engine performance was analyzed. Which was the theoretic base for parameters optimization of elements.④ Calculation result was compared with experimental result, so engine performance numerical simulation is feasible.2) The 3D numerical simulation of JL069 engine intake flow in FIRE.⑤ The geometry model was constructed for the intake port and cylinder of JL069 engine by means of CAD, the mesh then was applied for this geometry with the mesh tool FAME.② After the appropriate mathematical and physical model was proposed, the numerical calculation was processed.③ Calculation result was treated and compared with experimental result, and conclusion was analyzed. The intake port flow coefficient was calculated basis on the result of numerical simulation when the valve at the different lifts. The relationship between flow coefficient and transient flow area was also calculated. Compared with the experiment result, the validation of calculation method was proved, so utilizing CFD to calculate intake port flow coefficient is feasible.The method of numerical simulation may used to improve the design of motorcycle engine, reduce the design time and design expense. At the same time, this article has the important science meaning and engineering application value.