# US 4,391,231 A · Cylinder head for air-cooled engines

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- Number: US 4,391,231 A
- Document ID: US4391231A
- Status: Granted
- Kind: A
- Application number: 06/226,593
- Filed: 1981-01-21
- Granted: 1983-07-05
- Earliest claimed: 1980-03-04
- Assignees: Mitsubishi Jukogyo Kabushiki Kaisha
- Inventors: Yoshikazu TateBe; Masafumi Egami; Toshimitsu Miyawaki
- Web page: https://patentgrep.com/patent/US4391231A

## CPC

- F02F 1/32: the cylinder heads being of overhead valve type
- F02B 1/04: with fuel-air mixture admission into cylinder
- F02F 7/006: {Camshaft or pushrod housings}
- F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)

## Abstract

The present invention is to provide a cylinder head for air-cooled engines wherein a part of the top wall is depressed to form a rocker arm chamber and a cooling wind passage reaching the upper part of a suction port from the side of an exhaust port is formed between the bottom wall of the rocker arm chamber and the upper wall of a cylinder fitting surface, whereby the advantage of the performance of a conventional overhead valve engine is retained as it is, the defect of the increase of the height is kept as little as possible and the cooling performance is not reduced.

## Claims

### Claim 1

A cylinder head with a head body for an overhead valve, air-cooled engine having a rocker arm chamber (c), a suction port (21) and an exhaust port (7), comprising a part of a top wall of the cylinder head being depressed downwardly to form said rocker arm chamber (c) and defining a top of a first cooling wind passage (H) which extends over an upper part (15) of said suction portion, said part of the top wall of the cylinder head extending from a side of said exhaust port (7), said first passage (H) formed between a bottom wall (14) of said rocker arm chamber (c) and an upper wall of a cylinder fitting surface (10) of said head, said suction port (21) extending from a top of said upper wall of said cylinder fitting surface, a fin (17) extending around said first passage on a side thereof opposite said exhaust port (7), and a cooling wind guide (19) for guiding a cooling wind to a spark plug side of head, formed integrally with said cylinder head body on a side thereof opposite said cooling first cooling wind passage (H) and near said exhaust port (7) to form a second cooling wind passage (K), said first and second passages passing on opposite sides of said exhaust port.

### Claim 2 (depends on 1)

A cylinder head for air-cooled engines according to claim 1 wherein said cooling wind guide is a loosely bent L-shaped cooling wind guide having a first plate surface substantially parallel with the flow of the cooling wind and a second plate surface bent downwardly at a fixed angle from said first plate surface.