Abstract
The flow pattern on the gas flow through exhaust valves in Diesel engines is considered very important in relating to the utilizing exhaust gas energy, the charging efficiency, and the contamination of exhaust valves. But this problem has not satisfactorily been made clear. We have done visualization test gas flow through the exhaust valves using the chimney tunnel and found that these air flow have a two different flow pattern according to the increase valve lift.
The first flow pattern until some definite amount of lift is seen as a flow along the surface of valve stem and apart from the inside of valve seat accompanying a dead water region.
The second flow pattern after some definite amount of lift is seen as a flow apart from both of the surface of valve stem and inside of valve seat accompanying dead water region.
We have known that the flow quantity at the second flow pattern is no significant change for the increasing of valve lift, since air flow passage is nearly no change.
For the analytical investigation of this flow, we analysed using the flux analysis.
For example, we have calculated 20mm of valve lift and have obtained its flow pattern and the shape of the dead water region.
