# US 4,393,012 A · Temperature-responsive control device for carburetor

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- Number: US 4,393,012 A
- Document ID: US4393012A
- Status: Granted
- Kind: A
- Application number: 06/336,081
- Filed: 1981-12-31
- Granted: 1983-07-12
- Earliest claimed: 1981-03-09
- Assignees: Toyota Jidosha Kogyo Kabushiki Kaisha
- Inventors: Takashi Kato; Masaharu Hayakawa
- Web page: https://patentgrep.com/patent/US4393012A

## CPC

- G05D 23/1921: {using a thermal motor}
- F02M 1/10: dependent on engine temperature, e.g. having thermostat
- F02M 1/12: with means for electrically heating thermostat
- F02M 7/28: dependent on temperature or pressure
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF

## Abstract

A temperature-responsive control device for carburetors in which a heat-generating body produces heat as the engine is started from the cold state to heat up a heat-mass through an annular contact portion. The heat-mass temperature then rises with a certain time lag to the rise of the temperature of the heat-generating body. A thermo-wax unit is heated by the direct contact of its heat sensing portion with the heat-mass or through a contacting flange in a manner to isolate and float the heat-sensing portion to make a temperature rise substantially in conformity with the engine warming up characteristics or approximating as much as possible the same, to dismiss the choke mechanism and the fast idle cam at adequate timing through the action of the actuating rod. In consequence, it is possible to obtain a good driveability. When the engine is re-started in the heated state, the thermowax has been cooled approximating the cooling characteristics of the engine to avoid excessive enrichment of the mixture to ensure a safe re-starting of the engine.

## Claims

### Claim 1

A temperature-responsive control device for carburetor having a case attached to said carburetor, a heat-generating body disposed in said case, a thermo-wax disposed to oppose to said heat-generating body across a heat-mass and an actuating rod connected to said thermo-wax, wherein the improvement comprises that the portion of said heat-mass opposing and contacting said heat-generating body is protruded in an annular form.

### Claim 2 (depends on 1)

A temperature-responsive control device for carburetors as claimed in claim 1, wherein the portion of said heat-mass opposing and contacting said heat-generating body is constituted by a plurality of island-like protrusions arranged in an annular form.

### Claim 3

A temperature-responsive control device for carburetor having a case attached to said carburetor, a heat-generating body disposed in said case, a thermo-wax disposed to oppose to said heat-generating body across a heat-mass and an actuating rod connected to said thermo-wax, wherein the improvement comprises that the portion of said heat-mass opposing and contacting said heat-generating body is protruded in an annular form and that said thermo-wax has a temperature sensing portion spaced from said heat-mass and having a flange portion contacting in an annular form with said heat-mass.

### Claim 4 (depends on 3)

A temperature-responsive control device for carburetors as claimed in claim 3, wherein the flange portion of said thermo-wax makes contact with said heat-mass in such a manner as to leave a slit between said flange portion and said heat-mass.

### Claim 5

A temperature-responsive control device for carburetors having a case attached to said carburetor, a heat-generating body disposed in said case, a thermo-wax disposed to oppose to said heat-generating body across a heat-mass, and an actuating rod connected to said thermo-wax, an improvement which comprises that the portion of said heat-mass opposing and contacting said heat-generating body is protruded in an annular form, while a part of the heat-sensing portion of said thermo-wax contacts said heat-mass in such a manner that a flange portion of said thermo-wax is spaced from said heat mass.