Abstract: A power supply comprises a DC power source, first and second DC/DC converters, and a protection circuit. The DC power source provides DC power at a variable bulk voltage. The first DC/DC converter converts the DC power from the DC power source to DC power at a high voltage suitable for powering a high-voltage load. The second DC/DC converter receives DC power from the first DC/DC converter, converts the received DC power to DC power at a low voltage, and delivers the DC power at the low voltage to a low-voltage load. The protection circuit selectively transfers DC power from the first DC/DC converter to the high-voltage load. The DC power source may be an AC/DC converter receiving AC power from a power generator driven by an aircraft engine.

Abstract: An aircraft propeller drive system has a gear to be driven by an engine and having a first plurality of teeth. A torsion bar has a first end driven by the gear and a second end rotatable relative to the first end about a torsion axis by a torsion angle. An output shaft is driven by the second end and is adapted for connection to a propeller. A clutch has a driven member rotationally fixed to the output shaft and a driving member having a second plurality of teeth. The first and second pluralities of teeth engage each other when a variation in the torsion angle from a mean torsion angle is greater than a predetermined angle. Torque is transferred between the gear and the output shaft via the clutch when the first and second pluralities of teeth engage each other.

Abstract: An aircraft propeller drive system has a gear to be driven by an engine and having a first plurality of teeth. A torsion bar has a first end driven by the gear and a second end rotatable relative to the first end about a torsion axis by a torsion angle. An output shaft is driven by the second end and is adapted for connection to a propeller. A clutch has a driven member rotationally fixed to the output shaft and a driving member having a second plurality of teeth. The first and second pluralities of teeth engage each other when a variation in the torsion angle from a mean torsion angle is greater than a predetermined angle. Torque is transferred between the gear and the output shaft via the clutch when the first and second pluralities of teeth engage each other.

Abstract: An aircraft propeller drive system has a gear to be driven by an engine and having a first plurality of teeth. A torsion bar has a first end driven by the gear and a second end rotatable relative to the first end about a torsion axis by a torsion angle. An output shaft is driven by the second end and is adapted for connection to a propeller. A clutch has a driven member rotationally fixed to the output shaft and a driving member having a second plurality of teeth. The first and second pluralities of teeth engage each other when a variation in the torsion angle from a mean torsion angle is greater than a predetermined angle. Torque is transferred between the gear and the output shaft via the clutch when the first and second pluralities of teeth engage each other.

Abstract: An aircraft propeller drive system has a gear to be driven by an engine and having a first plurality of teeth. A torsion bar has a first end driven by the gear and a second end rotatable relative to the first end about a torsion axis by a torsion angle. An output shaft is driven by the second end and is adapted for connection to a propeller. A clutch has a driven member rotationally fixed to the output shaft and a driving member having a second plurality of teeth. The first and second pluralities of teeth engage each other when a variation in the torsion angle from a mean torsion angle is greater than a predetermined angle. Torque is transferred between the gear and the output shaft via the clutch when the first and second pluralities of teeth engage each other.

Abstract: A method of supplying air to an air spring biasing one of an intake valve and an exhaust valve of an internal combustion engine to a closed position is disclosed. The method includes: driving an air compressor with a motor prior to starting of the internal combustion engine, the air compressor fluidly communicating with the air spring to supply air to the air spring; determining that a predetermined condition has been reached; starting the engine once the predetermined condition has been reached; and driving the air compressor with a rotating shaft of the engine once the engine has started.

Abstract: A method of supplying air to an air spring biasing one of an intake valve and an exhaust valve of an internal combustion engine to a closed position is disclosed. The method includes: driving an air compressor with a motor prior to starting of the internal combustion engine, the air compressor fluidly communicating with the air spring to supply air to the air spring; determining that a predetermined condition has been reached; starting the engine once the predetermined condition has been reached; and driving the air compressor with a rotating shaft of the engine once the engine has started.

Abstract: An internal combustion engine has at least one intake valve and at least one exhaust valve. A first spring biases the at least one intake valve to a closed position. A second spring biases the at least one exhaust valve to a closed position. At least one of the first and second springs is an air spring. An air compressor fluidly communicates with the air spring to supply air to the air spring. The air compressor is operatively connected to a rotating shaft of the engine to be selectively driven thereby. A motor is operatively connected to the air compressor to selectively drive the air compressor. A method of supplying air to the air spring of the above engine is also disclosed. A method of supplying air to an air spring of an engine having both a mechanical and an electrical air compressor is also disclosed.

Abstract: An internal combustion engine has at least one intake valve and at least one exhaust valve. A first spring biases the at least one intake valve to a closed position. A second spring biases the at least one exhaust valve to a closed position. At least one of the first and second springs is an air spring. An air compressor is disposed inside the cylinder head and fluidly communicates with the air spring to supply air to the air spring. The air compressor being disposed between a crankshaft and a cylinder head cover in a direction parallel to a cylinder axis is also disclosed.

Abstract: An internal combustion engine has at least one intake valve and at least one exhaust valve. A first spring biases the at least one intake valve to a closed position. A second spring biases the at least one exhaust valve to a closed position. At least one of the first and second springs is an air spring. An air compressor is disposed inside the cylinder head and fluidly communicates with the air spring to supply air to the air spring. The air compressor being disposed between a crankshaft and a cylinder head cover in a direction parallel to a cylinder axis is also disclosed.

Abstract: An internal combustion engine has at least one intake valve and at least one exhaust valve. A first spring biases the at least one intake valve to a closed position. A second spring biases the at least one exhaust valve to a closed position. At least one of the first and second springs is an air spring. An air compressor fluidly communicates with the air spring to supply air to the air spring. The air compressor is operatively connected to a rotating shaft of the engine to be selectively driven thereby. A motor is operatively connected to the air compressor to selectively drive the air compressor. A method of supplying air to the air spring of the above engine is also disclosed. A method of supplying air to an air spring of an engine having both a mechanical and an electrical air compressor is also disclosed.

Abstract: A boat has a hull, a deck having a deck floor, and an engine disposed in the hull. A top of the engine is disposed vertically below the deck floor. The engine includes a crankcase, a crankshaft, a pair of cylinder banks connected to the crankcase at an angle relative to each other. A transom extends generally vertically upwardly from a rear portion of the hull. A stern drive unit is connected to the transom and is operatively connected to the engine through the transom. In another aspect, a marine engine has a crankcase, a cylinder block, and a crankshaft. An output shaft is disposed vertically above the crankshaft. The output shaft is disposed at least partially internal to the engine. A drive, internal to the engine, is operatively connected to the crankshaft and the output shaft. A driveshaft coupling is disposed on the output shaft.

Abstract: A marine engine has a crankcase and a cylinder bank. An upper end of the cylinder bank defines a plane. A cylinder head is connected to the upper end of the cylinder bank. A crankshaft is disposed in the crankcase. A pump is operatively connected to the crankshaft so as to be operatively driven thereby. A center of the pump is disposed above the plane defined by the upper end of the cylinder bank. In another aspect, a marine engine has a crankcase and a crankshaft. A starter ring gear is disposed on an end portion of the crankshaft. A diameter of the starter ring gear is less than a width of the crankcase. A starter motor selectively engages the starter ring gear and is disposed such that the starter ring gear is disposed between the crankcase and the starter motor.

Abstract: A cooling system and method of cooling an engine are disclosed. The cooling system includes a first closed loop that circulates coolant at a first temperature and a second closed loop that circulates coolant at a second temperature that is different than the first temperature. Such a construction provides two separate cooling temperature circuits for cooling equipment at different cooling temperatures.

Abstract: An arrangement for exhaust timing control by controlling the effective height of an exhaust port of a cylinder of a two-cycle internal combustion engine and comprising a control valve assembly arranged in a guide channel so as to be displaceable relative to the exhaust port and having an associated operating assembly for shifting thereof, the control valve assembly, in its advanced position, decreases the height of the exhaust port and, in its retracted position, exposes the entire cross-section of the exhaust port; a seal effective between the guide and the control valve assembly is provided in the end region of the control valve assembly facing the exhaust port.

Abstract: An internal combustion engine has a crankcase (2) and a fuel injection system (21) supplied with compressed air, whose piston compressor (12) has a piston (15) guided in a cylinder (18) and a driving crankshaft in operating connection with the engine crankshaft (6). To produce favorable construction conditions, the crankcase (2) constitutes the cylinder (18) for the piston (15) of the piston compressor (12).