The Parametric Design Method Based On Test And Simulation Study Of Circulation Performance On Diesel Engine Intake Port

The intake port as an important part of the cylinder head, whose geometry and positionrelative to the cylinder determined the flow coefficient and the size of the swirl strength,which have an important impact on power and economy of diesel engines. In this paper, theauthor carried out some research work such as quickly and efficiently intake portthree-dimensional design, using the test method to evaluate the pros and cons of the intakeport, using the software named FIRE to simulate the intake port flow and used to improve thedesign of the intake port, as well as the key structural parameters of the helical intake port andits flow properties and regularity, based on the previous research about the design of theintake port. Developed a kind of parametric design method of intake port which has a goodrobustness, and the design time can be shortened about 3/4; An advanced helical and straightairway concept of dual intake port was introduced, effectively solved the contradictionbetween the size of the swirl strength and flow coefficient. Ultimately the author formed a fastand efficient parametric design method to helical and straight intake port.The author processed the resin model by rapid prototyping technology，completed thesteady flow experiments, simulated the flow properties of the intake port by a CFD analysissoftware, and improved the intake port on this basis. Finally the author did some researchesabout the relationship between the flow properties of intake port and the key structuralparameters and positional parameters.Because the method of parametric design has advantages of short development cycle andmodify easily, etc, it was used to design the engine intake port in this paper. This paper mainlydescribed the parametric design method of a more complex shape of the helical intake port,and established a parametric helix and straight double intake port model of a diesel-type, andcompleted a resin core box of intake port by the rapid prototyping technology.The steady flow test of the engine intake port has many characteristics such as simpleequipment, easy operation, low cost and suitable for batch testing. The author got the flowcoefficient and swirl under each valve lift in the intake port steady flow test rig produced by the company of AVL.Not only can we get the macroscopic flow characteristics of the intake port flow such ascoefficient and swirl ratio through three-dimensional flow numerical simulation software, butalso we can get the micro-information of internal flow field, which can provide an importantbasis for the further improving design. In this paper, the author got the flow coefficient andswirl ratio of the intake port model above corresponding to every valve lift throughthree-dimensional numerical simulation using the software FIRE, and simulation andexperimental results were compared to results in good agreement. Then the author analyzedthe flow field of the cylinder, pointed out the defects of the intake port model, proposedimprovement measures, did a numerical simulation to the improved intake port model, andthe simulation results show that the flow coefficient and swirl ratio are improved.Helical intake port is the key component of the diesel engine. To study the impacts of mainstructural parameters and the relative position on the flow properties will help to get an idealmodel in the design and development of the intake port. The author through the thought of“control variables”selected six key parameters of the helical intake port and the locationparameter to study the impacts of their changes on the flow properties.