Abstract
Requirements of friendly environmental car have increased in recent years. The advancement of fuel efficiency, the clean exhaust gas, and so on by improvement of the exhaust systems are requested in the automobile industry. The flow structure inside the exhaust manifold affects the performance of the exhaust systems. The present study is carried out to understand the characteristics of the unsteady flow in an exhaust manifold under a room temperature condition. The flow is measured by a hot-wire anemometry and some laser techniques. It is confirmed that the flow direction in the exhaust manifold changed between -40deg. to 10deg. of the BTDC, because the pressure inside the cylinder at the BTDC becomes negative under the motoring engine condition.
