Abstract: An engine assembly for a vehicle includes an internal combustion engine and an exhaust system. The exhaust system includes a catalytic converter, a main muffler, a hydrocarbon trap, a pre-muffler disposed upstream from the main muffler and the hydrocarbon trap, and an exhaust path valve. The exhaust path valve is movable between first and second exhaust path positions. The exhaust path valve obstructs a second exhaust path in the first exhaust path position such that exhaust gas flows from an exhaust port of an engine cylinder to the catalytic converter to the main muffler and to the atmosphere. The exhaust path valve obstructs a first exhaust path in the second exhaust path position such that exhaust gas flows from the exhaust port of the engine cylinder to the catalytic converter to the hydrocarbon trap and to the atmosphere.

Abstract: A method of operating an exhaust valve of a two-stroke internal combustion engine is disclosed. The engine has a cylinder and a piston movably disposed within the cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid from the cylinder. The exhaust valve is configured to cyclically obstruct the exhaust port. The method includes: rotating the exhaust valve in a first direction for clearing the exhaust port before the piston uncovers the exhaust port during a downstroke of the piston, the first direction being opposite a direction of rotation of a crankshaft of the engine; and rotating the exhaust valve in the first direction for at least partially closing the exhaust port before the piston fully covers the exhaust port during an upstroke of the piston, said rotating of the exhaust valve relative to the rotation of the crankshaft at least partially counterbalancing the crankshaft.

Abstract: An engine assembly for a vehicle includes an internal combustion engine operating on a two-stroke engine cycle. A compressor is in fluid communication with an intake port of at least one cylinder of the engine to pump air into the engine. An exhaust pipe is in fluid communication with an exhaust port of the at least one cylinder. The exhaust pipe has an inlet and an outlet defining a length of the exhaust pipe therebetween. A diameter of the exhaust pipe increases along a portion of the length of the exhaust pipe in a flow direction of the exhaust pipe. The diameter of the exhaust pipe does not decrease along the length of the exhaust pipe in the flow direction of the exhaust pipe.

Abstract: An engine assembly for a vehicle includes an internal combustion engine operating on a two-stroke engine cycle. A compressor is in fluid communication with an intake port of at least one cylinder of the engine to pump air into the engine. An exhaust pipe is in fluid communication with an exhaust port of the at least one cylinder. The exhaust pipe has an inlet and an outlet defining a length of the exhaust pipe therebetween. A diameter of the exhaust pipe increases along a portion of the length of the exhaust pipe in a flow direction of the exhaust pipe. The diameter of the exhaust pipe does not decrease along the length of the exhaust pipe in the flow direction of the exhaust pipe.

Abstract: A method of operating an exhaust valve of a two-stroke internal combustion engine is disclosed. The engine has a cylinder and a piston movably disposed within the cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid from the cylinder. The exhaust valve is configured to cyclically obstruct the exhaust port. The method includes: rotating the exhaust valve in a first direction for clearing the exhaust port before the piston uncovers the exhaust port during a downstroke of the piston, the first direction being opposite a direction of rotation of a crankshaft of the engine; and rotating the exhaust valve in the first direction for at least partially closing the exhaust port before the piston fully covers the exhaust port during an upstroke of the piston, said rotating of the exhaust valve relative to the rotation of the crankshaft at least partially counterbalancing the crankshaft.

Abstract: A two-stroke internal combustion engine has a crankshaft disposed at least in part in a crankcase, and a cylinder block connected to the crankcase and defining a cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid. A piston is movably disposed within the cylinder and is operatively connected to the crankshaft. The piston is movable along a cylinder axis in a reciprocating motion including an upstroke and a downstroke. An exhaust valve assembly is operatively connected to and rotates with the crankshaft. The exhaust valve assembly has a shaft rotatably supported by the cylinder block and a valve configured to cyclically obstruct the exhaust port. The valve is operable to move clear of the exhaust port before the piston uncovers the exhaust port during its downstroke, and at least partially close the exhaust port before the piston fully covers the exhaust port during its upstroke.

Abstract: An electric kart has a frame, a seat, four wheels, an electric motor operatively connected to two of the wheels, and at least one battery operatively connected to the electric motor. The at least one battery has a support structure mounted to the frame of the electric kart, and battery cells positioned on the support structure such that there is at least one air passage defined between the battery cells. Air passes through the at least one air passage when the electric kart is in motion to cool at least some of the battery cells. A battery for an electric kart is also disclosed.

Abstract: A turbocharger for an engine includes a housing, a shaft, a turbine wheel mounted to the shaft for rotation therewith, a compressor wheel mounted to the shaft for rotation therewith, and a bearing cartridge rotatably supporting the shaft relative to the housing. The housing is positioned axially between the turbine and compressor wheels. The bearing cartridge includes an inner ring mounted to the shaft, an outer ring disposed between the inner ring and the housing and movable relative to the housing, and a first and a second plurality of roller elements axially spaced apart from one another and disposed radially between the inner and outer rings to rotatably support the inner ring relative to the outer ring. A radial gap (RD) is defined between the outer ring (134) and the housing (126). Lubricant flows into the radial gap and radially separates the outer ring from the housing during operation of the turbocharger.

Abstract: A drive assembly for a kart, and a kart including the assembly is disclosed. The assembly includes an electric motor including an output shaft; an assembly housing surrounding the motor, the housing defining an aperture; an intermediate shaft rotatably disposed within the assembly housing; a driving gear removably disposed on the output shaft within the housing; a reduction gear removably disposed on the intermediate shaft within the housing; and a panel removably connected to the housing for selectively covering the aperture, the driving gear and the reduction gear being removable from the motor and the housing via the aperture when the panel is removed from the housing, the panel, the driving gear, and the reduction gear being disposed above a maximum level of transmission oil contained within the housing when the motor is not operating. A method of changing a kart transmission ratio is also disclosed.

Abstract: A turbocharger for an engine includes a housing, a shaft, a turbine wheel mounted to the shaft for rotation therewith, a compressor wheel mounted to the shaft for rotation therewith, and a bearing cartridge rotatably supporting the shaft relative to the housing. The housing is positioned axially between the turbine and compressor wheels. The bearing cartridge includes an inner ring mounted to the shaft, an outer ring disposed between the inner ring and the housing and movable relative to the housing, and a first and a second plurality of roller elements axially spaced apart from one another and disposed radially between the inner and outer rings to rotatably support the inner ring relative to the outer ring. A radial gap (RD) is defined between the outer ring (134) and the housing (126). Lubricant flows into the radial gap and radially separates the outer ring from the housing during operation of the turbocharger.

Abstract: A two-stroke internal combustion engine has a crankshaft disposed at least in part in a crankcase, and a cylinder block connected to the crankcase and defining a cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid. A piston is movably disposed within the cylinder and is operatively connected to the crankshaft. The piston is movable along a cylinder axis in a reciprocating motion including an upstroke and a downstroke. An exhaust valve assembly is operatively connected to and rotates with the crankshaft. The exhaust valve assembly has a shaft rotatably supported by the cylinder block and a valve configured to cyclically obstruct the exhaust port. The valve is operable to move clear of the exhaust port before the piston uncovers the exhaust port during its downstroke, and at least partially close the exhaust port before the piston fully covers the exhaust port during its upstroke.

Abstract: A drive assembly for a kart, and a kart including the assembly is disclosed. The assembly includes an electric motor including an output shaft; an assembly housing surrounding the motor, the housing defining an aperture; an intermediate shaft rotatably disposed within the assembly housing; a driving gear removably disposed on the output shaft within the housing; a reduction gear removably disposed on the intermediate shaft within the housing; and a panel removably connected to the housing for selectively covering the aperture, the driving gear and the reduction gear being removable from the motor and the housing via the aperture when the panel is removed from the housing, the panel, the driving gear, and the reduction gear being disposed above a maximum level of transmission oil contained within the housing when the motor is not operating. A method of changing a kart transmission ratio is also disclosed.

Abstract: An electric kart has a frame, a seat, four wheels, an electric motor operatively connected to two of the wheels, and at least one battery operatively connected to the electric motor. The at least one battery has a support structure mounted to the frame of the electric kart, and battery cells positioned on the support structure such that there is at least one air passage defined between the battery cells. Air passes through the at least one air passage when the electric kart is in motion to cool at least some of the battery cells. A battery for an electric kart is also disclosed.

Abstract: A method for changing a gear driving configuration of a discrete gear transmission (DGT) in a powertrain including an engine operatively connected to a continuously variable transmission (CVT). The DGT has a DGT input shaft operatively connected to a CVT driven pulley, a plurality of gears having a plurality of gear driving configurations and a DGT output shaft selectively operatively connected to the DGT input shaft based on the gear driving configuration. Responsive to a gear shift request, a target driven pulley speed is determined for synchronizing the DGT input shaft with the DGT output shaft for the desired gear driving configuration. The engine is controlled to change an engine speed to the target engine speed corresponding to the determined target driven pulley speed. Responsive to the DGT input shaft being synchronized with the DGT output shaft, the current gear driving configuration is changed to the desired gear driving configuration.

Abstract: A drive assembly for a kart, and a kart including the assembly is disclosed. The assembly includes an electric motor including an output shaft; an assembly housing surrounding the motor, the housing defining an aperture; an intermediate shaft rotatably disposed within the assembly housing; a driving gear removably disposed on the output shaft within the housing; a reduction gear removably disposed on the intermediate shaft within the housing; and a panel removably connected to the housing for selectively covering the aperture, the driving gear and the reduction gear being removable from the motor and the housing via the aperture when the panel is removed from the housing, the panel, the driving gear, and the reduction gear being disposed above a maximum level of transmission oil contained within the housing when the motor is not operating. A method of changing a kart transmission ratio is also disclosed.

Abstract: A vehicle includes an engine that powers a wheel through a drive train. The drive train includes a continuously variable transmission (CVT) and toothed gearing disposed between the CVT and the wheel. A release clutch is also disposed between the CVT and the wheel. A controller controls the release clutch so as to disengage the clutch when the engine is not running and engage the clutch when the engine is running. The controller includes a hydraulic cylinder that fluidly connects to the engine's oil system so that engine-generated oil pressure engages the release clutch. Disengagement of the release clutch makes it easier to push the vehicle when the engine is not running, for example, when the engine breaks down.

Abstract: An air intake system for an internal combustion engine has at least one air box and a short duct for each cylinder. Each duct can be extended to provide higher torque at low speed. At high speed, the shorter duct length can be selectively provided for enhanced engine performance.

Abstract: A watercraft includes a shell, a ride plate, an internal combustion engine, and a jet pump. The shell defines a tunnel that extends forwardly from the transom and is defined laterally by the shell. The tunnel is open at its bottom The ride plate mounts to the shell under the tunnel. The engine and jet pump are supported by the ride plate and disposed in the tunnel. The engine drives the jet pump. The engine is cooled by water that continuously flows past the ride plate. The engine, jet pump, and ride plate are installed from below or the behind the shell.

Abstract: A continuously variable transmission (“CVT”) is disclosed. The CVT includes a drive pulley adapted to connect to a crankshaft of an engine. The drive pulley has inner and outer halves with belt engagement surfaces to engage the sides of the belt. The drive pulley of the CVT also includes a slide sleeve disposed on the shaft adapted to engage an inner side of a belt. The inner and outer halves of the drive pulley are biased apart from one another by a spring. The slide sleeve engages the belt when the belt is stationary or traveling at low speeds. The driven pulley includes inner and outer halves with belt engagement surfaces. The two halves are biased into contact with one another. A connector connects the inner half to the outer half. In addition, a pneumatically-actuated driven pulley is described together with a CVT incorporating same.

Abstract: A vehicle includes an engine that powers a wheel through a drive train. The drive train includes a continuously variable transmission (CVT) and toothed gearing disposed between the CVT and the wheel. A release clutch is also disposed between the CVT and the wheel. A controller controls the release clutch so as to disengage the clutch when the engine is not running and engage the clutch when the engine is running. The controller includes a hydraulic cylinder that fluidly connects to the engine's oil system so that engine-generated oil pressure engages the release clutch. Disengagement of the release clutch makes it easier to push the vehicle when the engine is not running, for example, when the engine breaks down.