Intake Noise and Behavior of Exhaust Valve on the Condition of Exhaust Braking in Automotive Engines

Abstract

Using the simulation program, the exhaust manifold and the exhaust valve system to optimize the exhaust brake performance in automotive engines have been investigated on the basis of the evaluations of the exhaust valve behavior, the pumping loss and the intake noise level. It is found that exhaust brake performance can be improved effectively by utilizing the pressure pulsation in the exhaust manifold, and am manifold of the divided type is desirable for this improvement. The intake noise level on the condition of exhaust braking is increased due to two back flows: one is the flow from the exhaust manifold to the intake manifold in the period of the valve over-lap, and the other is the flow from the exhaust manifold to the cylinder due to the re-opening of exhaust valve which occurs on the suction stroke.