Abstract: A turbocharger system comprises a first relatively small turbocharger and a second relatively large turbocharger connected in series and an exhaust gas flow control valve. The exhaust control valve has an inlet port communicating with the exhaust gas flow upstream of the first turbine a first outlet port communicating with the exhaust flow downstream of said first turbine but upstream of said second turbine, and a second outlet port communicating with the exhaust flow downstream of said second turbine. The valve is operable to selectively permit or block flow through the first and second outlet ports.

Abstract: A turbocharger system comprises a first relatively small high-pressure (HP) turbocharger (1) and a second relatively large low pressure (LP) turbocharger (2). The turbine (6) of the LP turbocharger (2) is connected in series downstream of the turbine (4) of the HP turbocharger (1) in a first exhaust gas passage (11). An exhaust bypass flow passage (12) provides a bypass flow path around the HP turbine (4). A rotary valve (8) is located at a junction of the bypass flow passage (12) and a first exhaust gas flow passage (11). The rotary valve (8) comprises a valve rotor (19) which is rotatable to selectively permit or block flow to the LP turbine (6) from either the first exhaust gas passage (11) or the bypass gas passage (12). The valve (8) is operated during a fired mode of the engine to block exhaust gas flow through the exhaust bypass and at least partially restrict exhaust flow to the LP turbine to raise the exhaust gas temperature.

Abstract: A turbocharger system comprises a first relatively small high-pressure (HP) turbocharger (1) and a second relatively large low pressure (LP) turbocharger (2). The turbine (6) of the LP turbocharger (2) is connected in series downstream of the turbine (4) of the HP turbocharger (1) in a first exhaust gas passage (11). An exhaust bypass flow passage (12) provides a bypass flow path around the HP turbine (4). A rotary valve (8) is located at a junction of the bypass flow passage (12) and a first exhaust gas flow passage (11). The rotary valve (8) comprises a valve rotor (19) which is rotatable to selectively permit or block flow to the LP turbine (6) from either the first exhaust gas passage (11) or the bypass gas passage (12). The rotary valve (8) is operated to at least partially restrict flow to the LP turbine to generate a braking back pressure.

Abstract: A turbocharger system comprises a first relatively small high-pressure (HP) turbocharger (1) and a second relatively large low pressure (LP) turbocharger (2). The turbine (6) of the LP turbocharger (2) is connected in series downstream of the turbine (4) of the HP turbocharger (1) in a first exhaust gas passage (11). An exhaust bypass flow passage (12) provides a bypass flow path around the HP turbine (4). A rotary valve (8) is located at a junction of the bypass flow passage (12) and a first exhaust gas flow passage (11). The rotary valve (8) comprises a valve rotor (19) which is rotatable to selectively permit or block flow to the LP turbine (6) from either the first exhaust gas passage (11) or the bypass gas passage (12).