Research On Design Method Of Plastic Air Intake Manifold Cavity For Gasoline Engine

Plastic air intake manifolds are successfully replacing aluminum air intake manifolds. Good performance, lower weight and costs are the main reasons behind this trend. But the manifold has an intricate shape owing to its performance and layout requirements, so it is difficult to design and produce. To bring the plastic manifold into practical use in China, this paper mainly researches the design method of plastic air intake manifold cavity for gasoline engine.Firstly,the configuration function of plastic air intake manifold for gasoline engine was analyzed, and the design requirement of each accessory was proposed. Then the wave resonance and the energy loss of intake manifold were researched in detail, which are important to manifold design. On the base, the way of design plastic air intake manifold cavity was put forward.After studying the numerical simulation of unsteady flow in intake manifold, 3 different gasoline engine models were set up using simulation software AVL-BOOST. Through one-dimensional engine cycle and gas exchange simulation, the influence of the plenum volume, manifold length and diameter on engine performance were found out. Then the principle of the cavity design was proposed, which can provide the fundamental structure parameters for intake manifold cavity design.The theory of CFD assisted in engine development was studied. And the mesh structure was also researched which was the key point to compute precision. The three-dimensional numerical simulation of air flows in two plastic air intake manifolds of gasoline engine was performed using CFD software FIRE. The simulated flow field provided a detailed insight into the three-dimensional air flow under different conditions. The calculation results of manifolds flow performance can provide theoretical directions for intake manifold cavity design.The two plastic intake manifold cavities mold designed with 3D designing software were used to make original samples quickly in the rapid prototype center. The engine test development was finished with these samples, including flow performance assessment, assembly checkout and engine testing. Finally, the testing results showed that this method was reasonable and correct.The design method of plastic air intake manifold for gasoline engine proposed in...