Split cycle engine with crossover shuttle valve
A split-cycle internal combustion engine (ICE) is provided, comprising a compression cylinder, an expansion cylinder and a crossover valve having a valve cylinder housing inside a shuttle and a combustion chamber structure defining a combustion chamber. The shuttle is configured to perform reciprocating motion inside the valve cylinder synchronously with a compression piston and an expansion piston, thereby alternatingly fluidly coupling and decoupling the combustion chamber with the compression cylinder and with the expansion cylinder, selectively. Sealing rings positioned between the valve cylinder and the shuttle prevent gas leaks between them during the reciprocating motion. In some embodiments, a phase shift between the pistons may be set or varied by a piston phase transmission gear. A bi-directional fluid flow split-cycle internal combustion engine (ICE) is also provided having a first cylinder, a second cylinder, a combustion chamber and a single crossover valve fluidly communicating them.
1. A split-cycle internal combustion engine comprising:
a first cylinder housing a first piston, and a second cylinder housing a second piston, wherein one of said first piston and second piston performs an intake stroke and a compression stroke, whereas the other of said first piston and second piston performs an expansion stroke and an exhaust stroke, and
a crossover valve comprising a valve cylinder and a shuttle comprising at least one port and configured to slide inside said valve cylinder in a reciprocating motion along said valve cylinder, said crossover valve being thereby configured to selectively fluidly associate and disassociate, via said at least one port, said first cylinder and said second cylinder with a combustion chamber defined by a combustion chamber structure fixed inside said valve cylinder.
2. The engine of claim 1 further comprising cylinder sealing rings positioned between said valve cylinder and said shuttle, said cylinder sealing rings preventing gas leaks between said valve cylinder and said shuttle during said reciprocating motion.
3. The engine of claim 1 wherein said shuttle comprises a cylindrical sleeve and said combustion chamber structure is positioned inside said cylindrical sleeve so that said cylindrical sleeve slides between an internal surface of said valve cylinder and an external surface of said combustion chamber structure during said reciprocating motion.
4. The engine of claim 3 further comprising chamber sealing rings positioned between said cylindrical sleeve and said combustion chamber structure, thereby preventing gas leaks between said cylindrical sleeve and said combustion chamber structure during said reciprocating motion.
5. The engine of claim 1 wherein said valve cylinder of said crossover valve is arranged perpendicular to said first cylinder and to said second cylinder.
6. The engine of claim 1 wherein said engine is configured in an in-line configuration, said first cylinder and said second cylinder being arranged substantially in parallel and said valve cylinder is arranged on top of said first cylinder and said second cylinder.
7. The engine of claim 1 wherein said engine is configured in an opposed configuration, said valve cylinder is arranged between said first cylinder and said second cylinder.
8. The engine of claim 1 wherein said crossover valve is configured to simultaneously fluidly associate said first cylinder and said second cylinder with said combustion chamber during a portion of said reciprocating motion.
9. The engine of claim 1 wherein reciprocating motion of said shuttle is synchronous with said strokes of said pistons.
10. The engine of claim 9 wherein said first piston performs an intake stroke and a compression stroke but not an exhaust stroke, and said second piston performs an expansion stroke and an exhaust stroke, but not an intake stroke.
11. The engine of claim 10 wherein said first piston is retarded relative to the second piston by up to 60 crankshaft degrees.
12. The engine of claim 10 wherein said first piston is advanced relative to said second piston by up to 60 crankshaft degrees.
13. The engine of claim 10 wherein said first piston reaches its TDC point together with said second piston.
14. The engine of claim 1 wherein said first cylinder and said second cylinder are thermally isolated from one another, thereby having different temperatures when said pistons perform said strokes.
15. The engine of claim 1 wherein said first cylinder is smaller than said second cylinder.
16. The engine of claim 1 wherein said first cylinder and said second cylinder have substantially equal volumes.