Split-cycle aircraft engine

A split-cycle air hybrid aircraft engine comprising:

• a crankshaft rotatable about a crankshaft axis;
• a power piston slidably received within a power cylinder and operatively connected to the crankshaft such that the power piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft;
• a compression piston slidably received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft;
• a gas crossover passage operatively interconnecting the compression cylinder and the power cylinder, the gas crossover passage including an inlet valve and an outlet valve defining a pressure chamber therebetween;
• an air reservoir operatively connected to the pressure chamber by a reservoir passage at a location between the inlet valve and the outlet valve of the pressure chamber, the air reservoir being selectively operable to receive compressed air from the compression cylinder and to deliver compressed air to the power cylinder for use in transmitting power to the crankshaft during engine operation;
• valves selectively controlling gas flow into and out of the compression cylinder, the power cylinder, and the air reservoir;
• wherein the engine is mounted to an aircraft and the air reservoir is disposed within the aircraft;
• wherein the engine is operable in a high pressure (HP) mode, in the HP mode:
• the compression cylinder is selectively controllable to operate as a power cylinder having an expansion stroke and an exhaust stroke;
• and
• both the power cylinder and the compression cylinder receive compressed air from the air reservoir which is expanded on the compression and power cylinder's respective expansion strokes and discharged on their respective exhaust strokes.