A variable geometry turbine comprising: a wheel supported for rotation about an axis; a housing comprising a first volute for receiving gas from a first source and a second volute for receiving gas from a second source; the first and second volutes being separated by a dividing wall; and an inlet passageway surrounding the wheel and fluidly connected to the volutes; the inlet passageway at least partially defined between a first wall and an opposite second wall, the first wall being moveable along the axis to vary the size of the inlet passageway; wherein a tip of the dividing wall defines a first radius relative to the axis, and a radially outermost part of the first wall positioned within the inlet passageway defines a second radius relative to the axis, and wherein the first radius is at least around 1% larger than the second radius.

Engine controllers and control schemes are provided for managing engine state transitions requiring increased compressor pressure ratios in turbocharged engines. In some circumstances, turbo lag can be mitigated by initially transitioning the engine to an intermediate engine state that directly or indirectly increases airflow through the engine and turbocharger relative to what would be possible if the engine were immediately commanded to operate at the target engine state. After reaching a point where the desired torque is actually generated at the intermediate engine state, the operational settings are gradually reduced to the target effective firing density while increasing the operational compressor pressure ratio to the target compressor ratio.

Engine controllers and control schemes are provided for managing engine state transitions requiring increased compressor pressure ratios in turbocharged engines. In some circumstances, turbo lag can be mitigated by initially transitioning the engine to an intermediate engine state that directly or indirectly increases airflow through the engine and turbocharger relative to what would be possible if the engine were immediately commanded to operate at the target engine state. After reaching a point where the desired torque is actually generated at the intermediate engine state, the operational settings are gradually reduced to the target effective firing density while increasing the operational compressor pressure ratio to the target compressor ratio.

A turbocharger includes a variable nozzle unit, a bearing housing, a circular heat shield plate located between a turbine impeller and the bearing housing, and a water chamber formed in the bearing housing. The heat shield plate is fixed by being pressed against the variable nozzle unit by a disc spring and is radially aligned by being fitted into the bearing housing by a fitting portion. The heat shield plate includes a fitting surface formed in the fitting portion and an inner peripheral heat shield portion projecting radially inward from the fitting surface and located with an axial gap between the inner peripheral heat shield portion and the bearing housing. At least a part of the water chamber exists at the same radial position as a radial position of the fitting portion.

A turbocharger includes a variable nozzle disposed between a turbine housing and a bearing housing and a spring having an annular shape. The spring is disposed between the variable nozzle and the bearing housing, and is configured to generate a biasing force that biases the variable nozzle away from the bearing housing to widen a spacing between the variable nozzle and the bearing housing in a rotation axis direction. The spring includes an outer peripheral portion that applies the biasing force to the variable nozzle and an inner peripheral portion that comes into contact with the bearing housing. The outer peripheral portion of the spring is located further away from the turbine housing than the inner peripheral portion of the spring in the rotation axis direction.

A variable capacity turbocharger includes a housing, a turbine impeller at least partially located in the housing, a scroll flow path located in the housing and encircling the turbine impeller, a first nozzle ring and a second nozzle ring facing each other in the housing, a nozzle flow path located between the first nozzle ring and the second nozzle ring and fluidly coupling the scroll flow path to the turbine impeller, a gap formed between the first nozzle ring and the housing, and a bearing hole located in the first nozzle ring and including an opening adjacent to the gap. The gap is located on an opposite side of the first nozzle ring to the nozzle flow path. Additionally, the gap is connected to the scroll flow path.

A variable capacity turbocharger includes a housing, a turbine impeller at least partially located in the housing, a scroll flow path located in the housing and encircling the turbine impeller, a first nozzle ring and a second nozzle ring facing each other in the housing, a nozzle flow path located between the first nozzle ring and the second nozzle ring and fluidly coupling the scroll flow path to the turbine impeller, a gap formed between the first nozzle ring and the housing, and a bearing hole located in the first nozzle ring and including an opening adjacent to the gap. The gap is located on an opposite side of the first nozzle ring to the nozzle flow path. Additionally, the gap is connected to the scroll flow path.

Provided are a variable geometry turbine and a supercharger including the same that can change flow rate characteristics of a turbine in accordance with engine output with simple structure and can adjust the flow angle of a fluid flowing into a turbine impeller to any angle in the circumferential direction of the turbine impeller. The variable geometry turbine (10) includes a turbine impeller (12) configured to rotate about an axis line, a turbine housing (30) configured to accommodate the turbine impeller (12) and form a throat passage (32) and a scroll flow channel (34) on the outer circumferential side of the turbine impeller (12), the scroll flow channel (34) communicating with the throat passage (32), and a width changing mechanism in which a width change portion (52) that changes a passage width of the throat passage (32) along the circumferential direction of the turbine impeller (12) is movable in the width direction of the passage width.

Provided are a variable geometry turbine and a supercharger including the same that can change flow rate characteristics of a turbine in accordance with engine output with simple structure and can adjust the flow angle of a fluid flowing into a turbine impeller to any angle in the circumferential direction of the turbine impeller. The variable geometry turbine (10) includes a turbine impeller (12) configured to rotate about an axis line, a turbine housing (30) configured to accommodate the turbine impeller (12) and form a throat passage (32) and a scroll flow channel (34) on the outer circumferential side of the turbine impeller (12), the scroll flow channel (34) communicating with the throat passage (32), and a width changing mechanism in which a width change portion (52) that changes a passage width of the throat passage (32) along the circumferential direction of the turbine impeller (12) is movable in the width direction of the passage width.

A conventional gasoline engine is retrofitted and calibrated to operate as a bi-fuel engine using Hydrogen as the second fuel. When operated with Hydrogen, which typically leads to a reduction of engine output power, the engine is preferably operated in a charged mode and in a lean mode with the engine throttle kept in a wide-open position during charged and lean mode operation resulting in a more efficient engine with a reduction of engine output power loss.