Patent ID: 7578129

Claim:
A valve for regulating flow of exhaust gas to a turbocharger in a multiple-turbocharger system, comprising: a housing having an inlet port for receiving exhaust gas from an internal combustion engine, an outlet port through which exhaust gas is discharged for supply to a turbocharger, and a cavity in fluid communication with the inlet and outlet ports; a valve seat disposed in the cavity, the valve seat being generally tubular and having a radially outer surface and a radially inner surface, the valve seat including at least one aperture extending therethrough from the radially outer surface to the radially inner surface; a valve member disposed in the cavity and axially slidable relative to the valve seat between (a) a closed position engaging the valve seat so as to prevent flow of exhaust gas between the valve member and valve seat to the outlet port, and (b) an open position allowing flow of exhaust gas between the valve member and valve seat to the outlet port; a leakage pathway extending from the inlet port between the valve seat and the housing to the outlet port, such that even when the valve member is in the closed position, exhaust gas entering the inlet port flows through the leakage pathway to the outlet port, a portion of the leakage pathway being defined between the radially outer surface of the valve seat and an inner surface of the housing; and a seal arranged between a radially outer surface of the valve member and the radially inner surface of the valve seat such that the seal prevents flow between the radially outer surface of the valve member and the radially inner surface of the valve seat.