Crash simulation of the new TNGA intake manifold in glass-fiber-reinforced polyamide: Breakage-behavior optimization through crash-test-correlated simulation

摘要

In order to accelerate the 2050 challenge of 'New Vehicle Zero CO_2 Emission' Toyota is developing a new engine series for lower fuel consumption, higher performance and globally better productivity based on the 'Toyota New Global Architecture (TNGA) concept'. For the 1.5L gasoline engine a new intake manifold was developed in collaboration between Novares, Toyota Motor Corporation and Toyota Motor Europe. Many challenges arose in achieving a high performance, high function reliability, light and compact design whilst also fulfilling the severe strength requirements (vehicle crash and burst pressure). Toyota is committed to moving people in the safest and most responsible way. In order to better assess and represent people's safety in the event of a road accident, the Euro-NCAP is implementing from 2020 a new frontal impact test called MPDB. In this new assessment, speed and vehicle overlap have increased, resulting in more strain on the engine compartment parts. For the TNGA engine the intake manifold is positioned in the front of the engine compartment and is impacted during a frontal crash test. This paper describes the philosophy and methodology used to prevent contact between the intake manifold and the fuel system in order to rule out fuel leakage during a crash test. From initial crash test simulations, the behavior and breakage mode of the intake manifold were analysed and an innovative design was selected. In this design the surge tank breaks off and is pushed under the ports at high impact forces. These ports were designed with a high rigidity in order to act as a barrier to prevent the intake manifold from coming into contact with the fuel system. The CAE model was then correlated with a component crash test to further improve its accuracy by optimizing the material model parameters: Young's modulus and the breakage strain rate. From this optimization, a good correlation of 'impactor force' versus 'impactor stroke' could be seen. Through subsequent CAE development, material was added to increase stiffness in the critical areas and a high degree of weight reduction was achieved by removing material in non-critical/non-functional areas. The final optimized design results in a best-in-class strength-to-weight ratio intake manifold which has no contact with the low pressure fuel system during vehicle crash tests.