Idle sound quality enhancement with optimizing exhaust manifold structure on a H8 engine
2022-01-0737
03/29/2022
- Event
- Content
- Idle sound quality for motorcycle is critical to engineers to achieve. People would like to have a strong individualized sound in idle, but linear and smooth sound in driving condition. Since the idle fluctuation noise is based on the engine firing order, the exhaust manifold structure and the idle frequency by cylinder numbers, thus, compared to the two or three cylinders engines, eight or six cylinders engine are really hard to get a fluctuated tailpipe sound since the its higher firing frequency. However, the surrogate methodology can be applied on these engines. Based on the noise cancellation process in phase and amplitude in the exhaust manifold tube, engineers can manipulate the noise with several lower peaks compare to other higher peaks. In this scenario, people can feel the noise with big fluctuations although the smaller noise peaks are still there but in the masking. In this paper, a special case is presented by this methodology. In that case, an eight cylinders horizontal engine with uneven firing orders initially makes very irregular tailpipe noise in the idle condition. With optimizing the exhaust manifold design with different shapes and expansion length. The tailpipe noise is finally sounds as a four cylinders engine. All the process is run in DOE by GT power model and also can be applied to the six or four cylinders engine.
- Citation
- Tan, Y., "Idle sound quality enhancement with optimizing exhaust manifold structure on a H8 engine," SAE Technical Paper 2022-01-0737, 2022, .