Patent ID: 8210138

Claim:
A split-cycle engine comprising: a crankshaft rotatable about a crankshaft axis; 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; an expansion piston slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft; a crossover passage interconnecting the expansion and compression cylinders, the crossover passage including a crossover compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween; and a pilot crossover valve disposed between the crossover passage and the expansion cylinder; wherein the pilot crossover valve equalizes fluid pressures acting against the crossover expansion (XovrE) valve in an opening direction, reducing the forces required in actuating the crossover expansion (XovrE) valve.