US2762352A

US2762352A - Autoamtic choke means

Info

Publication number: US2762352A
Application number: US460008A
Authority: US
Inventors: John G Else
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1954-10-04
Filing date: 1954-10-04
Publication date: 1956-09-11
Anticipated expiration: 1973-09-11

Description

Sept. 11, 1956 .1. e. ELSE AUTOMATIC CHOKE MEANS 2 SheetsSheet 1 Filed 001;. 4, 1954 Sept. 11, 1956 J. G. ELSE 2,762,352

AUTOMATIC CHOKE MEANS Filed Oct. 4, 1954 2 Sheets-Sheet 2 INVENTOR AUTOMATIC CHOKE MEANS John G. Else, Royal Oak, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application ()ctober 4, 1954, Serial No. 460,008

13 Claims. (Cl. 123-119) The present invention relates to internal combustion engines and more particularly to automatic choke means therefor.

When starting or operating a cold internal combustion engine, it is desirable to increase the fuel-air mixture ratio. This may be easily accomplished by means of a choke valve disposed in the intake of the carburetor. Since the required amount of choking will be a function of the engine temperature, the position of the choke valve may be controlled by suitable thermostatic means responsive to the engine temperature. The engine exhaust gases have been found to be a reliable index to the engines temperature, and accordingly, it has been the practice to heat the thermostatic element in the choke by means of air that has passed through a stove which is in heat exchanging relation with the engine exhaust gases. Although this has proved quite effective, considerable trouble has been experienced in transferring the correct amount of heat to the air for insuring proper operation of the choke valve. As a result, the choke valve either opens before the engine has become properly heated or the valve opens prematurely before the engine is adequately heated.

It is now proposed to provide a stove which is adapted to be disposed in heat exchanging relation with the engine exhaust gases for heating the air flowing to the thermostatic element in the automatic choke. The stove may be formed integrally in the exhaust manifold so as to have one side thereof open to the atmosphere. One or more fins may be provided in the stove so as to form a tortuous path for increasing the amount of heat transferred to the air in the stove. A cover may be secured to the manifold so as to cooperate with the fin to define one Wall of the path. In order to insure the temperature of the air in the stove being an accurate function of the engine temperature, the cover may include thermal insulating means to prevent excessive heat losses to the atmosphere. In the present instance this means is provided by employing a cover which includes two members that are spaced from each other to form a dead air space therebetween. Thus as the air is drawn through the stove, it will be heated by the exhaust gases and when it passes the thermostat, it will cause the choke valve to be moved as a function of the engine temperature. By providing the insulating means the eifects of the atmospheric temperatures will be greatly reduced and the temperature of the heated air will be a closer function of the engine temperature.

Fig. l is an end view of an engine employing the present invention.

Fig. 2 is a side view of the exhaust manifold taken substantially along the plane of line 22 in Fig. 1.

Fig. 3 is a cross sectional view taken substantially along the plane of line 3-3 in Fig. 2.

Fig. 4 is a cross sectional view taken substantially along the plane of line 44 in Fig. 2.

i Fig. 5 is a cross sectional view taken substantially along the plane of line 5-5 in Fig. 2.

nited States Patent 0 ice Fig. 6 is a perspective view of the cover for the present stove with a portion thereof being broken away.

The present invention may be adapted for use on any suitable engine 10 such as a V-type engine having a pair of angularly disposd banks of cylinders 12 with an induction system 14 disposed therebetween. The induction system 14 may include a carburetor 16 which is mounted on an intake manifold 18 that has the opposite sides thereof abutting the cylinder heads 20. The manifold 18 may include one or more distribution passages which are adapted to distribute the combustible charge of fuel and air from the carburetor 16 to the various cylinders.

Exhaust manifolds 22 may extend along the opposite sides of the engine 10 for collecting the exhaust gases from the cylinder combustion chambers and discharging them into the atmosphere. In the present instance the exhaust manifolds 22 include a plurality of exhaust ports 24 that communicate with a chamber 26 for collecting the exhaust gases from the engine 10. An outlet may be provided which communicates with the chamber 26 for discharging the exhaust gases into an exhaust system and/ or the atmosphere.

A choke valve 28 may be provided in the intake of the carburetor 16 for movement between the opened and closed positions to vary the air-fuel mixture ratio. Since the variations in the air-fuel mixture are a function of the engines temperature, a thermostat 30 may be provided for controlling the valves 28 position. This thermostat 30 may be of any desired form such as a bimetallic spring member and it may include a housing on the side of the carburetor 16. In order to correlate this thermostat 30 with the engine temperature, air may be heated by the engine exhaust gases and circulated through the housing of the thermostat. A stove 32 may be provided in the exhaust manifold 22 in heat exchanging relation with the hot exhaust gases flowing therethrough and a tube 34 may be provided which will interconnect the stove 32 with the interior of the housing 30. Thus the interior of this housing will be heated in proportion to the engine temperature.

The stove 32 may be formed in the exhaust manifold 22 as an integral part of the casting, and it may include a cavity 35 that is formed in one wall of the manifold so as to have one side 36 thereof open to the atmosphere. A cover 38 may be secured to the manifold 22 to close this open side and form a chamber 40. An inlet 42 may be provided for air to enter this chamber 40from the atmosphere and an outlet 44 may be provided in the manifold for allowing the tube 34 to interconnect the chamber 40 with the interior of the housing. Thus air may be drawn from the atmosphere and passed through the chamber 40, be heated by the exhaust gases and carried to the thermostat 30 to heat it. In order to increase the amount of heat transferred to the air in the chamber 40, one or more fins 46 may be provided in the chamber 40 so as to extend out toward the cover 3S and cause the air to follow a tortuous path. Thus the inlet 42 may communicate with one end of the path with the outlet 44 communicating with the other end.

The cover 38 may include an inner member 50 and an outer member 52 which are preferably spaced from each other. The inlet 42 may be formed by registering openings 48 in the cover 38. The inner member 50, in the present instance, is a plate positioned adjacent the fins 46 in the chamber 40. The outer member 52 of the cover 38 may be dished so as to project outwardly from the inner member 50 and form a dead air space 54 therebetween. This air space 54 will act as a very effective Thus when the engine is operating, the air will be drawn through the registering openings 48 into the tortuous path in the stove 32. Accordingly, the air therein will be heated in proportion to the engine temperature. As the air is heated it may then flow from the outlet 44 into the tube 34 and into the interior of the thermostatic housing 30. By properly proportioning the path and the spacing between the inner and outer members 50 and 52, respectively, forming the cover 38, the amount of heat transferred to the air may be varied to provide the optimum amount of heat for thermostat 30. By increasing the spacing between the two covers, the amount of insulation may be varied so that the effects of atmospheric temperature variations will not aifect the temperature of the air flowing to the thermostat thus making the thermostat more responsive to engine tem perature.

It will thus be seen that a heat stove for an automatic choke has been provided which may easily be constructed to insure proper heating of the choke so that it will be more nearly a function of the engine temperature.

I claim:

1. Means for heating a thermostatic element in a choke comprising a stove for heating the air flowing to said element, said stove having one side thereof forming a portion of a wall of an exhaust manifold and being in direct heat exchanging relation with the engine exhaust gases in said manifold, and an outlet in said stove adapted to receive means for interconnecting said stove with said thermostatic element.

2. A stove for a choke having thermal responsive means operatively connected thereto, said stove comprising a pocket projecting into an exhaust manifold to form at least a portion of one Wall thereof in heat exchanging relation with the exhaust gases inside of said manifold, another side of said pocket being open to the atmosphere, a cover secured to said manifold across said open side for closing said open side and thereby forming an air passage in heat exchanging relation with said exhaust gases and outlet means in said pocket communicating with said air passage and being adapted to be connected to said thermal responsive means.

3. An exhaust manifold comprising a member having a chamber therein for collecting exhaust gases discharged from an engine, a housing formed integrally in one wall of said manifold to project into said chamber in heat exchanging relation with the exhaust gases therein, one side of said housing being open to the atmosphere, a cover attached to said manifold to close said open side and form a tortuous path in said housing in heat exchanging relation with said exhaust gases, an inlet interconnecting said path in said housing with the atmosphere, and an outlet communicating with said path in said housing and being adapted to be connected to thermal responsive choke means.

4. An exhaust manifold comprising a member adapted to be secured to an engine, said member having a chamber therein for collecting the exhaust gases discharged fromsaid engine, a housing provided in one wall of said manifold to project into said chamber in heat exchanging relation with the exhaust gases therein, one side of said housing being open to the atmosphere, a cover attached to said manifold to close said open side, at least one fin in said housing cooperating with said cover so as to form a tortuous path in heat exchanging relation with said exhaust gases, an inlet interconnecting one end of said path with the atmosphere, an outlet communicating with the opposite end of said path and being adapted to be connected to thermal responsive choke means.

5. An exhaust manifold comprising a member adapted to be secured to an engine and having a chamber for collecting exhaust gases discharged from said engine, a housing provided in one wall of said manifold with one side thereof open to the atmosphere, a. cover attached to said manifold for closing said open side of said housing and forming a chamber disposed in heat exchanging relation with said exhaust gases, said cover including means for thermally insulating said chamber from the atmosphere, an inlet interconnecting said chamber with the atmosphere and an outlet communicating with said chamber and being adapted to communicate with thermal responsive choke means.

6. An exhaust manifold comprising a member adapted to be secured to an engine and having a chamber therein for collecting the exhaust gases discharged from said engine, a housing provided in one wall of said manifold to project into said chamber in heat exchanging relation with the exhaust gases therein, one side of said housing being open to the atmosphere, at least one fin positioned in said housing to define a tortuous path in heat exchanging relation with said exhaust gases, a cover attached to said manifold for closing said open side and cooperating With said fin to form one wall of said path, said cover including means for insulating the contents of said path from the atmosphere, an inlet interconnecting the atmosphere with one end of said path, and an outlet communicating with the opposite end of said path and being adapted to be connected to thermal responsive choke means.

7. An exhaust manifold comprising a member adapted to be secured to an engine and having a chamber therein for collecting the exhaust gases discharged from said engine, a housing provided in one wall of said manifold with one side thereof being open to the atmosphere, a cover attached to said manifold for closing said open side of said housing and forming a chamber disposed in heat exchanging relation with said exhaust gases, said cover including an inner member and an outer member disposed in spaced relation to each other to provide a dead air space therebetween for thermally insulating said chamber from the atmosphere, an inlet interconnecting said chamber with the atmosphere and an outlet communicating with said chamber and being adapted to com municate with thermal responsive choke means.

8. An exhaust manifold comprising a member adapted to be secured to an engine and having a chamber therein for collecting the exhaust gases discharged from said engine, a housing provided in one wall of said manifold to project into said chamber in heat exchanging relation Withthe exhaust gases therein, one side of said housing being open to the atmosphere, at least one fin positioned in said housing so as to define a tortuous path in heat exchanging relation with said exhaust gases, an inner cover attached to said manifold so as to close said open side and cooperate with said fin to form one wall of said path, an outer cover positioned on said inner cover and forming a dead air space therebetween for thermally insulating said path from the atmosphere, an inlet interconnecting the atmosphere with one end of said path, and an outlet communicating with the opposite end of said path and being adapted to be connected to an automatic choke.

9. In an engine having a carburetor with a thermal responsive choke thereon, the combination of an exhaust manifold for collecting the engine exhaust gases, a stove provided in said manifold to project into the interior thereof and form a substantially plane wall in heat exchanging relation with said exhaust gases, one side of said stove being open to the atmosphere, a cover secured to said manifold for closing said open side, an inlet interconnecting the interior of said stove with the atmosphere and an outlet communicating with said interior and with the thermal responsive means in said choke.

10. In an engine having a carburetor with a choke valve therein, the combination of a thermostatic element disposed inside of a housing for actuating said choke valve, an exhaust manifold for collecting the exhaust gases from said engine, a stove formed integral with one wall of said manifold to project into said exhaust gases in heat exchanging relation therewith and having one side thereof open to the atmosphere, at least one fin positioned in said housing to form a tortuous path, a cover secured to said manifold for closing said open side and cooperating with said fin to form one wall of said path, said cover including means for thermally insulating said path from the atmosphere, an inlet formed in said cover for interconnecting one wall of said path with the atmosphere, an outlet communicating with the other end of said path, and a passage interconnecting said outlet with the interior of said housing for carrying heated air from said path to said thermostatic element.

11. The combination of claim 10 wherein said cover includes an inner member and an outer member which are disposed in spaced relation with each other to form a dead air space therebetween.

12. An exhaust manifold for an engine having a choke automatically controlled by a thermostatic element, said exhaust manifold comprising a member having a chamber therein for collecting the exhaust gases discharged from said engine, a stove in one side of said member, one side of said stove forming at least a portion of one wall of said chamber and being in direct heat exchanging relation with the engine exhaust gases therein, an inlet for interconnecting said stove with the atmosphere and an outlet adapted for interconnecting said stove with said thermostatic element.

13. An exhaust manifold for an engine having a choke automatically controlled by a thermostatic element, said manifold comprising a member having a chamber therein for collecting the exhaust gases discharged from said engine, a recessed pocket formed in said member with one side thereof being open to the atmosphere, another side of said pocket forming a portion of one wall of said chamber and being in direct heat exchanging relation With the engine exhaust gases in said manifold, said open side of said pocket being adapted to be closed by a removable cover secured to said member to form an air path in heat exchanging relation with said exhaust gases and having one end thereof adapted to open to the atmosphere and the other end adapted to be connected to said thermostatic element.

Boyce Aug. 26, 1952 Meinzinger et a1 Sept. 29, 1953