# US 5,701,860 A · Decompressor for an internal combustion engine

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- Number: US 5,701,860 A
- Document ID: US5701860A
- Status: Granted
- Kind: A
- Application number: 08/692,214
- Filed: 1996-08-05
- Granted: 1997-12-30
- Earliest claimed: 1996-03-26
- Assignees: Ishikawajima-Shibaura Machinery Co., Ltd.
- Inventors: Hiroshi Horiuchi; Yuichi Momose; Takeshi Ushikoshi
- Web page: https://patentgrep.com/patent/US5701860A

## CPC

- F02N 19/004: {Aiding engine start by using decompression means or variable valve actuation}
- F01L 13/08: for decompression, e.g. during starting; for changing compression ratio
- F02N 3/02: having pull-cords
- F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES

## Abstract

A decompressor disposed to start an engine by a recoil starter and at this time compression pressure within a cylinder is adapted to escape therefrom, in which a decompression valve of the decompressor is disposed vertically with respect to a crank shaft or within a crank casing, so that a decompression valve does not laterally project from the cylinder and does not interfere with a cowling, whereby a compact engine is laid out, and also an interlocking mechanism of the decompression valve with the recoil starter becomes simple. Furthermore, a cam at the recoil reel is made variable correspondingly to the kind of engine so that the decompression timing during the starting is made variable so as to obtain the most suitable starting mechanism.

## Claims

### Claim 1

A decompressor for an internal combustion engine for escaping compression pressure in a cylinder, comprising:
a decompression valve disposed vertically with respect to a crank shaft and between a cylinder and a crank casing;
said cylinder having a decompression port and a communicating bore for releasing pressure and said decompression valve connecting said decompression port with said communicating bore;
an operating rod for opening said decompression valve to enable said decompression port at said cylinder and said communicating bore to communicate with each other; and
cams disposed on a side surface of a recoil reel at a recoil starter, and said operating rod having an end portion disposed proximate said cams, so that said recoil reel, when rotating, slides toward said crank shaft, whereby said cams push said operating rod to open said decompression valve.

### Claim 2 (depends on 1)

A decompressor for an internal combustion engine as set forth in claim 1, wherein said cams are made variable in accordance with a type of said internal combustion engine.

### Claim 3

A decompressor for an internal combustion engine for escaping compression pressure in a cylinder, comprising:
a decompression valve vertically disposed with respect to a crank shaft and between a cylinder and a crank casing;
said cylinder having a decompression port and a communicating bore for releasing pressure and said decompression valve connecting said decompression port with said communicating bore;
an operating rod for opening said decompression valve to enable said decompression port at said cylinder and said communicating bore to communicate with each other; and
a transmitting member for slidably engaging and moving said operating rod of said decompression valve, said transmitting member being disposed laterally of a recoil reel, and, said recoil reel, when rotating, being slidable toward said crank shaft so as to actuate said decompression valve by engaging and moving said transmitting member to lift said operating rod.

### Claim 4

A decompressor for an internal combustion engine for escaping compression pressure in a cylinder, comprising:
a decompression valve disposed in a crank casing;
an operating rod for said decompression valve projecting laterally toward a recoil reel;
a decompression port open in a cylinder, a check valve at said decompression port, and a pipe connecting said decompression port with an input of said decompression valve via said check valve, and said decompression valve having an output open to the atmosphere; and
said recoil reel, when rotating, being slidable toward a crank shaft to engage said operating rod to open said decompression valve.