Simulation and prediction of influence of newly designed cast exhaust manifold on engine performance

First of all, in order to further compare the influence of the newly designed stamping and welding exhaust manifold and the original casting exhaust manifold on the engine performance, the influence of the exhaust manifold on the engine performance was simulated with the help of thermodynamic analysis software. In the whole simulation experiment, the parameters of the engine model mainly refer to the actual parameters of the real engine, which are measured by the relevant technical personnel, and the actual operating parameters of the engine purchased in the early stage are taken as the reference to carry out the verification test of the model. Through the simulation calculation, the error of the final test value is small, no more than 1.2%, so it shows that the data model used in this experiment is available, which has a certain reference significance.

In order to further understand the influence of exhaust manifold on engine performance, two branch pipes in the newly designed exhaust manifold are designed. The branch pipe is discretized to get a new one-dimensional model. The model is simulated and brought into the engine model, which can simulate the real running state, the performance of the engine in the process of running, and get the engine 1500 ~ 6000r / min. The average effective pressure comparison can be obtained by comparing the exhaust conditions of the exhaust manifold simulating the engine operation.

It can be seen that on the basis of the original exhaust manifold, the optimization of the exhaust manifold can effectively improve the average effective pressure of the engine, and the exhaust effect of the exhaust manifold is better. Especially for some bending positions, this kind of area is the low and medium speed area of the exhaust manifold, which can improve the performance significantly.

In addition, through the calculation and analysis of the gas exchange process of the gasoline engine, it can be seen that the fundamental reason for the great improvement of the dynamic performance of the motor is the change of the form of the exhaust manifold. By optimizing the form of exhaust manifold, the intake air at the outlet of intake manifold has been significantly improved. In the intake stroke, the air flow of the optimized exhaust manifold has been significantly improved, and the air circulation quality has been increased.

This is due to the redesign of the exhaust manifold, and after the installation of the new exhaust manifold, the influence of the pressure of the first cylinder during the operation of the original organ is effectively reduced, so the air quality and fluidity are greatly enhanced. Moreover, through the observation of the final simulation results, it can be seen that after the optimization and improvement of the original exhaust manifold form, the process performance has been significantly improved, and the inlet pressure of the exhaust manifold is smaller. In this way, in the air exchange stage, it is more conducive to the realization of the whole system air exchange process, and has a good effect.

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