Cummins Ltd

There is disclosed a method of operating an exhaust system for receiving exhaust gas from an internal combustion engine. The exhaust system comprises: a turbine, a dosing module, at least one of a variable geometry mechanism and a bypass control valve, and a controller. The turbine is configured to receive exhaust gas from the internal combustion engine. The turbine comprises a turbine wheel configured to extract energy from the exhaust gas. The dosing module is configured to deliver an aftertreatment fluid to the exhaust gas at a position downstream of the turbine wheel. The variable geometry mechanism is configured to control the flow of exhaust gas delivered to the turbine wheel. The bypass control valve is configured to bypass a portion of the exhaust gas from a position upstream of the turbine wheel to a position downstream of the turbine wheel. The controller is configured to execute the method, the method comprising: determining a current property of the exhaust gas at a position downstream of the turbine wheel; determining a difference between the current property of the exhaust gas at the position downstream of the turbine wheel and a reference property of the exhaust gas at the position downstream of the turbine wheel; and in response to the difference, adjusting the at least one of the variable geometry mechanism and the bypass control valve.

A valve system comprising a valve chamber at a junction of an inlet port, an outlet port and a bypass port, the inlet port configured for fluid communication with exhaust gas, the outlet port configured for fluid communication with an inlet of a turbine, and the bypass port configured for fluid communication with an exhaust aftertreatment device; a rotary valve comprising a valve rotor which rotates about a valve axis within the valve chamber between a first position to permit gas flow through the bypass port and a second position to block gas flow. At least one of the valve rotor and the valve chamber comprises a protrusion and the other comprises a recess, wherein, in the first position, the protrusion and recess are spaced from one another, and, in the second position the recess receives the protrusion such that gas flow between the protrusion and recess is substantially prevented.

A rotary turbine bypass valve comprises a valve chamber and a valve rotor. The chamber is positioned at a junction of an inlet port, an outlet port and a bypass port. The inlet port is configured to receive exhaust gas, the outlet port is configured to fluidly communicate with a turbine inlet, and the bypass port is configured to fluidly communicate with an exhaust aftertreatment device. The rotor comprises a first and second recess, the first recess defining a primary flow passage, the second recess defining a secondary flow passage. The rotor is rotatable between a first position in which the rotor substantially blocks exhaust gas flow through the bypass port and a second position in which the rotor permits such. The secondary flow passage is configured to selectively permit fluid communication between the inlet port and the bypass port when the primary flow passage is partially blocked.

A rotary turbine bypass valve comprises a valve chamber positioned at a junction of an inlet port, an outlet port and a bypass port, the inlet port configured for fluid communication with a flow of exhaust gas from an engine, the outlet port configured for fluid communication with an inlet of a turbine, and the bypass port configured for fluid communication with an exhaust aftertreatment device; and a valve rotor supported for rotation, about a valve axis, within the valve chamber. The valve rotor is rotatable about the valve axis between a first position in which the valve rotor permits gas flow through the bypass port and a second position in which the valve rotor blocks gas flow through the bypass port. The valve rotor is eccentric such that it includes a seal portion which is a portion of the valve rotor within the valve chamber which is furthest radially spaced from the valve axis; and as the valve rotor moves from the first position to the second position the seal portion moves towards the bypass port such that the radial separation between the valve rotor and the bypass port decreases to a minimum when the valve rotor is in the second position in which the seal portion is adjacent the bypass port.

A valve system comprising a valve chamber at a junction of an inlet port, an outlet port and a bypass port, the inlet port configured for fluid communication with exhaust gas, the outlet port configured for fluid communication with an inlet of a turbine, and the bypass port configured for fluid communication with an exhaust aftertreatment device; a rotary valve comprising a valve rotor which rotates about a valve axis within the valve chamber between a first position to permit gas flow through the bypass port and a second position to block gas flow. At least one of the valve rotor and the valve chamber comprises a protrusion and the other comprises a recess, wherein, in the first position, the protrusion and recess are spaced from one another, and, in the second position the recess receives the protrusion such that gas flow between the protrusion and recess is substantially prevented.

A turbine bypass valve comprising: a casing defining first and second casing ports; and a valve cartridge mounted to the casing; wherein the valve cartridge comprises: first and second valve ports; and a valve member, the valve member being movable between a first position in which there is a flow path between the first and second valve ports, and a second position in which the valve member substantially blocks said flow path between the first and second valve ports; and wherein the valve cartridge is mounted to the casing such that the first valve port is aligned with the first casing port, and the second valve port is aligned with the second casing port.

A rotary turbine bypass valve comprises a valve chamber and a valve rotor. The chamber is positioned at a junction of an inlet port, an outlet port and a bypass port. The inlet port is configured to receive exhaust gas, the outlet port is configured to fluidly communicate with a turbine inlet, and the bypass port is configured to fluidly communicate with an exhaust aftertreatment device. The rotor comprises a first and second recess, the first recess defining a primary flow passage, the second recess defining a secondary flow passage. The rotor is rotatable between a first position in which the rotor substantially blocks exhaust gas flow through the bypass port and a second position in which the rotor permits such. The secondary flow passage is configured to selectively permit fluid communication between the inlet port and the bypass port when the primary flow passage is partially blocked.