Cylinder head and engine
To find compromises in the relationship between the component costs of intake and exhaust valves and the downsizing of an engine and the relationship between the cooling performance and the followability of the intake and exhaust valves and coordinate these conflicting relationships as much as possible. A hollow valve encapsulating coolant having a good cooling function is used as an exhaust valve, which is exposed to a higher temperature environment than an the intake valve, to eliminate a disincentive to downsizing. In contrast, a hollow valve that has no coolant, relatively low component cost, light weight, and good followability is used as the intake valve, which does not need to have a better cooling function than the exhaust valve and needs to have better followability than the exhaust valve to improve combustion efficiency.
1. A cylinder head for an internal combustion engine, the cylinder head comprising:
an intake valve having a stem and a valve head; and
an exhaust valve having a stem and a valve head,
wherein the intake valve is a hollow valve internally having an internal cavity charged with no coolant and
the exhaust valve is a hollow valve internally having an internal cavity charged with a coolant.
2. The cylinder head according to claim 1 ,
wherein the intake valve is a hollow head valve in which the internal cavity is provided in the stem and the valve head.
3. The cylinder head according to claim 2 ,
wherein the exhaust valve is a hollow head valve in which the internal cavity is provided in the stem and the valve head.
4. The cylinder head according to claim 3 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the length of the internal cavity of the intake valve is larger than the length of the internal cavity of the exhaust valve.
5. The cylinder head according to claim 3 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the diameter of the internal cavity of the intake valve is larger than the diameter of the internal cavity of the exhaust valve.
6. An engine comprising:
a cylinder block that holds a piston in a reciprocally movable manner in a cylinder and rotatably holds a crankshaft that converts a reciprocating motion of the piston to a rotational motion via a connecting rod; and
the cylinder head according to claim 3 , the cylinder communicating with a combustion chamber through the cylinder head, the cylinder head being fixed to the cylinder block.
7. The cylinder head according to claim 2 ,
wherein the exhaust valve is a hollow stem valve in which the internal cavity is provided in the stem.
8. The cylinder head according to claim 7 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the length of the internal cavity of the intake valve is larger than the length of the internal cavity of the exhaust valve.
9. The cylinder head according to claim 2 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the length of the internal cavity of the intake valve is larger than the length of the internal cavity of the exhaust valve.
10. The cylinder head according to claim 2 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the diameter of the internal cavity of the intake valve is larger than the diameter of the internal cavity of the exhaust valve.
11. An engine comprising:
a cylinder block that holds a piston in a reciprocally movable manner in a cylinder and rotatably holds a crankshaft that converts a reciprocating motion of the piston to a rotational motion via a connecting rod; and
the cylinder head according to claim 2 , the cylinder communicating with a combustion chamber through the cylinder head, the cylinder head being fixed to the cylinder block.
12. The cylinder head according to claim 1 ,
wherein the intake valve is a hollow stem valve in which the internal cavity is provided in the stem.
13. The cylinder head according to claim 12 ,
wherein the exhaust valve is a hollow head valve in which the internal cavity is provided in the stem and the valve head.
14. The cylinder head according to claim 12 ,
wherein the exhaust valve is a hollow stem valve in which the internal cavity is provided in the stem.
15. The cylinder head according to claim 12
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the length of the internal cavity of the intake valve is larger than the length of the internal cavity of the exhaust valve.
16. The cylinder head according to claim 12 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the diameter of the internal cavity of the intake valve is larger than the diameter of the internal cavity of the exhaust valve.
17. An engine comprising:
a cylinder block that holds a piston in a reciprocally movable manner in a cylinder and rotatably holds a crankshaft that converts a reciprocating motion of the piston to a rotational motion via a connecting rod; and
the cylinder head according to claim 12 , the cylinder communicating with a combustion chamber through the cylinder head, the cylinder head being fixed to the cylinder block.
18. The cylinder head according to claim 1 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the length of the internal cavity of the intake valve is larger than the length of the internal cavity of the exhaust valve.
19. The cylinder head according to claim 1 ,
wherein the diameter of the valve head of the intake valve is larger than the diameter of the valve head of the exhaust valve and the diameter of the internal cavity of the intake valve is larger than the diameter of the internal cavity of the exhaust valve.
20. An engine comprising:
a cylinder block that holds a piston in a reciprocally movable manner in a cylinder and rotatably holds a crankshaft that converts a reciprocating motion of the piston to a rotational motion via a connecting rod; and
the cylinder head according to claim 1 , the cylinder communicating with a combustion chamber through the cylinder head, the cylinder head being fixed to the cylinder block.