CN-115422795-B - GT-Suite modeling simulation method for integrated exhaust manifold

CN115422795BCN 115422795 BCN115422795 BCN 115422795BCN-115422795-B

Abstract

The invention provides an integrated exhaust manifold GT-Suite modeling simulation method, which is characterized in that a real exhaust valve flow coefficient test method under the condition of an integrated exhaust manifold technology is simulated in GT-Suite, an exhaust valve flow coefficient is calculated through simulation, and then the exhaust valve flow coefficient is substituted into a GT-Suite exhaust valve module to perform integrated exhaust manifold modeling, so that an available integrated exhaust manifold simulation model is obtained, and engine simulation with the integrated exhaust manifold technology is realized.

Inventors

XU TAO
YUAN SHAOWEI
WANG XIANGANG
JIANG PING
YANG ZHENGJUN

Assignees

重庆长安汽车股份有限公司
重庆长安汽车股份有限公司

Dates

Publication Date: 20260421
Application Date: 20220815
Priority Date: 20220815

Claims (6)

1. The GT-Suite modeling simulation method for the integrated exhaust manifold is characterized by comprising the following steps of: S1, processing an integrated exhaust manifold physical model by finite element software to obtain a format file; S2, converting the format file into a 1D model by using a GEM3D tool, and importing the 1D model into the GT-Suite; S3, adding a boundary module and a valve structure module to the 1D model according to a cylinder cover air passage flow test method to form an exhaust valve flow coefficient optimization model; S5, modeling a valve structure, and setting three parameters of a cylinder diameter, a valve lift/cylinder diameter and a flow coefficient; s6, setting a heat transfer model of the integrated exhaust manifold pipeline, wherein when the heat transfer model is set, if a fixed wall temperature mode is adopted, the solid surface temperature is required to be set to be normal temperature, and if a wall solving mode is adopted, the heat transfer boundary is required to be set to be the environment temperature during testing; s7, adding a control signal to control the lift of the exhaust valve of each cylinder; s8, calculating a difference f (x) between the flow of the exhaust valve in the model and the flow of the actually measured exhaust valve, and taking the difference as an optimization target; s9, optimizing, wherein an optimization variable selects an exhaust valve flow coefficient, and the optimization principle is f (x) minimum; S10, obtaining flow coefficients of exhaust valves of each cylinder under different valve lifts, and averaging optimization results of each cylinder under the same valve lift; S11, taking the optimization result into an integrated exhaust manifold model, calculating the flow of each cylinder under different valve lifts, and if the absolute value of the relative difference between the simulated calculated flow and the measured exhaust valve flow is smaller than a set standard, considering the integrated exhaust manifold simulation model as usable.
2. The integrated exhaust manifold GT-Suite modeling simulation method according to claim 1, wherein in s1, the integrated exhaust manifold physical model is subjected to internal surface extraction and grid division processing through HYPERMESH/ANSYS software, and converted into stl format.
3. The integrated exhaust manifold GT-Suite modeling simulation method according to any one of claims 1-2, wherein in S5, a ValveActuLiftCdConn module is selected to model a valve structure in a GT model library.
4. The integrated exhaust manifold GT-Suite modeling simulation method according to any one of claims 1-2 wherein in S7 the exhaust valve lift of each cylinder is controlled by adding SignalGenerator control signals.
5. The integrated exhaust manifold GT-Suite modeling simulation method according to any one of claims 1-2, wherein in S8, the difference f (x) between the exhaust valve flow and the measured exhaust valve flow in the model is calculated by adding MathEquation modules.
6. The integrated exhaust manifold GT-Suite modeling simulation method according to any one of claims 1-2, wherein in S9, optimization is performed using a Direct Optimizer module.

Description

GT-Suite modeling simulation method for integrated exhaust manifold Technical Field The invention relates to an exhaust manifold simulation technology, and belongs to the technical field of modeling of power components. Background GT-Suite is automobile simulation analysis software developed by Gamma Technologies corporation in the United states, and is mainly applied to analysis of vehicle design parameters, calculation of fuel consumption and noise under various running conditions, and evaluation of engine performance, evaluation of cooling system performance and the like. In the automobile industry, the GT-Suite series software can obviously shorten the period of design and development and reduce the production cost. The main process of building an exhaust manifold model in GT-Suite is currently generally: 1. the internal surface is extracted, grid division and the like are processed by HYPERMESH software on the exhaust manifold physical model, and converted into stl format. 2. The stl format file is converted into a 1D model by using a GEM3D tool, and the 1D model is imported into the GT-Suite. 3. In GT-Suite, the exhaust manifold is modeled according to the recommended exhaust passage modeling method. The file system provided by GT provides a modeling method of a traditional exhaust passage (the exhaust passage is separated from an exhaust manifold), since the traditional exhaust passage is relatively straight and has a short length, the flow loss caused by the shape and surface roughness of the traditional exhaust passage can be considered together with the throttle effect of a valve, namely, the total flow loss characteristics of the valve and the exhaust passage are generally unified to the flow coefficient characteristics of the air passage, the flow coefficient curve of the valve model is used for describing the GT model, the exhaust passage is simulated by a straight pipe with neglected friction, and the exhaust manifold part at the outlet of the exhaust passage is modeled according to the specific geometric structure of the exhaust passage. The specific method comprises (1) directly inputting the exhaust flow coefficient obtained by actual measurement into the GT-Suite exhaust valve module. (2) The 1D model in the above step was subjected to an internal surface friction treatment in GT-Suite, with the friction coefficient set to 0. The two steps are completed, and the available exhaust manifold simulation model is obtained and can be further used for engine simulation analysis. Integrating exhaust manifolds (exhaust ports and exhaust manifolds integrated) is a new technology that has matured in recent years and there is no corresponding modeling method in GT-Suite. For an engine adopting the integrated exhaust manifold technology, the exhaust passage and the exhaust manifold are integrated, the exhaust gas path structure is complex, the size is obviously longer than that of the traditional exhaust passage, the throttling loss caused by the gas path structure and friction is not suitable for being continuously and uniformly considered at a valve model, otherwise, the simulation calculation of the exhaust process (particularly when the load is large) generates obvious deviation, and the calculation of the in-cylinder pressure and the ventilation process of the engine generates larger error. If the exhaust flow coefficient actually measured in the test is directly input into the GT-Suite exhaust valve module, the model is distorted and cannot be used. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides an integrated exhaust manifold GT-Suite modeling simulation method, which aims at establishing an integrated exhaust manifold modeling method in GT-Suite, wherein the key is to process the flow coefficient of an exhaust valve in an integrated exhaust manifold model to obtain an available integrated exhaust manifold simulation model. The technical scheme of the invention is as follows: an integrated exhaust manifold GT-Suite modeling simulation method, the method comprising the steps of: S1, processing an integrated exhaust manifold physical model by finite element software to obtain a format file; S2, converting the format file into a 1D model by using a GEM3D tool, and importing the 1D model into the GT-Suite; S3, adding a boundary module and a valve structure module to the 1D model to form an exhaust valve flow coefficient optimization model; s4, setting pressure and temperature in the boundary module according to the boundary set by the cylinder cover air flue flow test. The cylinder cover air flue flow test is carried out by adopting a FEV method, a Ricardo method and an AVL method. The FEV method is to test the flow at different valve lifts by adjusting the valve lift from 1mm to an integer millimeter after the maximum valve lift and with a pressure differential of 5 kpa. S5, modeling a valve structure, and setting three parameters of a cylinder diamet