Multi-Body Dynamic Simulation and Experimental Validation of Valve Spring Surge Speed 2013-01-2770

Valve spring surge is one of the critical issues in an automotive engine that may cause catastrophic failure in an engine. The term surge refers to inter coil vibration of valve spring, which occurs when the natural frequency of the spring matches with the engine operating frequency. This surge happens when the engine speeds-up beyond the design limit under certain extreme operating conditions. The speed at which the valve spring surges is referred as valve spring surge speed. At this speed, the spring force starts deteriorating and eventually results in loss of contact between the valve train components. So, there is a need to predict the engine speed at which the valve-train components start losing contact and also explore possibilities to increase the surge speed by optimizing the valve spring design parameters. This paper is a physical extension of theoretical prediction of valve jump phenomenon for existing and proposed valve springs using multi-body dynamic ADAMS software^® [3].

In this paper, a non-fired version of H-series, 6 cylinders, TCI, Inline engine is taken up to experimentally measure the valve spring surge speeds with existing and proposed valve springs on a multi-functional test-rig. The proposed design points to an increase of approximately 200-300 rpm in surge speed, which amounts to an increase of seven percent. The experimental findings are compared with the simulation results and it is noted that there is a close correlation is observed between the simulation and experimental results. Simulation and experimental results for both existing and proposed springs correlate to within eight percent. Since the proposed valve spring has a higher surge speed as compared to the existing one, the valve-train failures in the field are expected to reduce significantly.