US3008697A

US3008697A - Temperature controlled accelerator pump

Info

Publication number: US3008697A
Application number: US741283A
Authority: US
Inventors: Lawrence C Dermond
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1958-06-11
Filing date: 1958-06-11
Publication date: 1961-11-14
Anticipated expiration: 1978-11-14

Description

Nov. 14, 1961 1.. c. DERMOND TEMPERATURE CONTROLLED ACCELERATOR PUMP Filed June 11, 1958 W 4 A fw\\\\\\\\\\\\v\\\\\\\\\\\\\\\\\\\ E KWZ M Mm M We W w w United States Patent PUMP Lawrence C. Dermond, Rochester, N.Y., assiguor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed June 11, 1958, Ser. No.*741,283

' 8 Claims. (Cl. 261-34) The present invention relates to a mechanism for varying the quantity of the charge of an accelerator pump in accordance with engine temperature. Inasmuch as an engine requires a larger accelerating charge when cold than when warm, it is desirable from economy and performance points of view to provide means whereby the acceleration charge is responsive to engine temperature.

Engine temperature responsive acceleration charge devices are not broadly new, however, such devices have, in the past, been frequently too complicated and hence too costly to be commercially feasible. It is therefore an object of the present invention to provide a simple and reliable means for regulating the acceleration charge in accordance with engine temperature whereby more eco nomical operation of a carburetor is realized.

In the present invention a temperature responsive valve mechanism is disposed within the fuel reservoir in such The details as well as other objects and advantages of A the present invention will be apparent from a perusal of the detail description which follows.

In the drawing:

FIG. 1 discloses a carburetor embodying the subject invention.

FIG. 2 is a View along line 22 of FIG. 1.

A carburetor is shown generally at 10 and includes a casing 12 within which a fuel reservoir 14 is formed. An accelerating pump is indicated generally at 16 and includes a cylinder casing 18 within which a piston 20 mounted on a rod 22 is slidably disposed. The piston rod 22 is suitably connected -to the accelerator pedal, not shown, so as to cause the rod to move downwardly within casing 18 when the pedal is depressed.

As set forth in greater detail in Patent 2,771,282 Olson et al., the accelerator pump piston 20 is axially movable relative to rod 22. A first spring 24 is seated within casing 18 and biases the piston in an upwardly or charging direction. A second spring 26 seats against a washer 28 fixed to rod 22 and at its other end biases piston 20 in a downwardly direction. Thus as the accelerator pedal is released, rod 22 moves tupwardly decreasing the rate of spring 26 permitting spring 24 to move the piston upwardly. The upward movement of the piston causes a ball check valve 30 in casing passage 32 to lift olf its seat 34 which in turn causes fuel from reservoir 14 to be drawn through a conduit 36 into the accelerating pump cylinder chamber 38.

An accelerator pump output passage 40 communicates through passage 32 with accelerator pump chamber 38. One end, the left as viewed in the drawing, communicates with the carburetor induction passage. Assume for the moment, that the other end 42 of passage 40 is to be blocked. As the accelerator pedal is depressed, the rate of spring 26 is increased so as to overcome the force of spring 24, moving piston 20 downwardly. This movement seats ball check valve 30 forcing a charge of fuel to be delivered to the carburetor induction passage to enrichen the fuel-air mixture to permit rapid acceleration.

As thus far described, the accelerator pump is of conventional design and forms no part of the present invention except insofar as it combines with a temperature sensitive mechanism now to be described.

The fuel reservoir casing 12 includes a hollow boss member 44 projecting upwardly within reservoir 14 and the interior of which boss communicates at its lower end with end 42 of accelerator pump discharge passage 40; A valve mechanism 46 is disposed within the open end of easing boss 44 and is adapted to permit fuel from the discharge passage 40 to be bypassed back to the fuel reservoir 14 in accordance with engine temperature.

Valve mechanism 46 includes a sleeve member having a flange 50 at one end thereof adapted to dependingly support the valve mechanism within boss 44. The sleeve member includes 'a plurality of sections 52, 54, and 56 of progressively reduced diameter and the largest 52 of which is open at its upper end and the smallest 56 of which is closed at its lower end to provide a valve supporting sleeve. The largest diameter portion 52 of the sleeve member coacts with the interior surface of boss 44 to provide a chamber 58 which is sealed from communication with fuel reservoir 14 except for a pair of diametral ports 60 formed in sleeve section 56.

A cylindrical valve member 62 is rotatably supported within sleeve section 5.6 through a temperature responsive thermostatic coil element 64. Coil 64 is in turn supported at its upper end through a washer-sleeve member 66, the latter being peripherally supported upon sleeve flange 50.

Cylindrical valve member 62 includes a diametral'passage 68 adapted to be aligned with diametral sleeve ports 60. Valve member 62 also includes a longitudinally extending passage 70 communicating diametral passage 68 with sleeve chamber 72 openly communicating with fuel reservoir 14.

The thermostatic coil 64 is adapted to wind or unwind inaccordance with the temperature of the fuel within reservoir which in turn reflects engine temperature. As the coil rotates, valve element diametral pas-sage 68 will move into or out of registry with ports 60 in sleeve section 56 to thereby control the quantity of fuel bypassed back to the reservoir 14 as the accelerator pump piston 20 moves downwardly to provide an accelerating charge to the carburetor induction passage.

Since rotation of coil 64 will cause the same to be lengthened or shortened to a small extent, the diametral ports 60 are made somewhat larger than valve element passage 68. In this way axial movement of member 62 due to changes in the aforenoted coil length, will not effect the registry between ports 60 and passage 62.

With the engine cold, the maximum quantity of accelerating charge is required, therefore, under these conditions, thermostatic coil 64 is adapted to rotate valve member 62 to move passage 68 completely out of registry with sleeve ports 60 whereby end 42 of discharge passage 40, is, in effect, blocked, permitting the entire accelerating charge to be supplied to the induction passage. As

the engine warms, coil 64 gradually moves the diametral passage 68 into registry with the sleeve ports 60 progressively increasing the quantity of accelerating charge which is bypassed back to the fuel reservoir whereby the accelerating charge supplied to the induction passage is incrementally reduced in accordance with engine temperature.

I claim:

1. A charge forming device for an internal combustion engine including an induction passage, a fuel reservoir, an accelerator pump, said accelerator pump including a discharge passage means communicating at one end with said induction passage, and valve means disposed in said fuel reservoir cooperating with said discharge passage to bypass -a portion of the fuel supplied by said accelerator pump to said discharge passage in accordance with changes in engine temperature, the other end of said discharge passage means communicating with said fuel reservoir, said valve mechanism including a valve element disposed in said discharge assage means, and a helically coiled fuel temperature responsive member supported within said reservoir and operatively connected to said valve element for controlling the quantity of fuel bypassed from said discharge passage means back to said, reservoir.

2. A charge forming device for an internal combustion engine including an induction passage, a fuel reservoir, an, accelerator pump, said. accelerator pump including a discharge passage means communicating at one end with said induction passage, a boss formed in and openly communicating with said fuel reservoir, said boss also communicating with the discharge passage means, valve, means disposed in said boss and adapted to bypass a portion of the fuel supplied by said accelerator pump to said discharge passage. in accordance with changes in engine temperature, the other end of said discharge passage means communicating with saidfuel reservoir, said valve mechanism including a valve element disposed in said discharge passage means, and. a fuel temperature responsive member operatively connected to said valve element for controlling the quantity of fuel bypassed from said discharge passage means back to said reservoir.

3. A charge. forming device as set forth in claim 2 in which said valve mechanism comprises a sleeve member supported within said boss, said sleeve and boss cooperating with the discharge passage means to define a chamber, port means in said sleeve adapted to communicate said chamber with the reservoir, said valve element adapted to cooperate with the port means to control the quantity of accelerator pump fuel bypassed to said reservoir in accordance with. engine fuel temperature.

4. A charge forming device as set forth in claim 3 in which the temperature responsive member comprises a 4 helically coiled element supported at one end upon said sleeve and connected at its other end to the valve element.

5. A charge forming device as set forth in claim 3 in which the sleeve member includes a first portion sup ported within said boss and open to said reservoir at one end, asecond; portion of smaHer cross-sectional area than the first portion, said port means being formed in the second sleeve. portion, said. second sleeve portion being adapted to rotatablysupport the. valve element.

6. A charge forming device as set forth in claim 5 in which said valve element includes passage means, one end of said passage means in communication with the reservoir and the other end of which is adapted to, register with said port means.

7'. A charge forming device as set forth in claim 6 in which the temperature responsive member comprises a helically coi-led element supported from the open end of the first sleeve portion, the other end of said temperature responsive element being connected to the valve element to. rotate the same in accordance with engine temperature changes to vary the registry between the port means and said valve element passage means.

8. A charge forming device as set forth in claim 7 in which the port means is sufficiently larger in diameter than said valve element passage means that the degree of said registry will be unaffected by the axial movement of said valve element occasioned by changes in length of the temperature responsive element.

Heitger Apr. 25, 1933 Boyce Ian, 13, 1953