Effect of exhaust runner length, valve timing and lift on the performance of a gasoline engine 2019-01-0771
IC engine exhaust system can influence the engine’s performance in a significant way. This paper shows that a variable exhaust manifold can affect the engine performance in terms of its output torque by about 7-10%. Similarly, other exhaust systems/functions affect the performance of the engine in different magnitudes. But when smaller improvements are clubbed together, a significant improvement can be achieved. This paper researches the combined effects of exhaust manifold and exhaust valve train system on engine’s performance. The exhaust valve timing can be adjusted to further improve the engine torque produced for the exhaust runner lengths analyzed. Study of a combined effect showed that the runner length requirement shifts slightly as the valve timing is changed. Due to practical limitations foreseen in having higher runner lengths and limitations in the rate of runner length variation, certain areas have to undergo through a region where the torque values are as low as they can be. Though this happens in every single exhaust system out in the market today, valve lift can be used to compensate this loss. In this research the engine torque loss at these points can be regained by 50% by taking benefit of a variable exhaust valve timing and valve lift system.