US3029801A - Electric fuel pump system - Google Patents

Description

April 17, 1962 J. P. CASASSA 3,029,801

' ELECTRIC FUEL PUMP SYSTEM Filed Jan. 25, 1960 IN VEN TOR.

United States Patent M aware Filed Jan. 25, 1960, Set. No. 4,396 2 Claims. (Cl. 123-179) This invention relates to fuel pump systems and more particularly to systems including electric pumps for providing internal combustion engines with fuel such as gasoline.

Electrically operated fuel pumps have a number of advantages not realized in the use of other types of pumps especially when used in automobiles. A difficulty, however, has been experienced in the use of electrically operated pumps for vehicles in that complications ensue in attempts to prevent pump operation when the engine being served by the pump stops because of mechanical failure or for some other reason. Obviously, the fuel pump should stop automatically and should be relied upon to do so when the engine stops, for if it were otherwise, fire or other damage is likely to occur.

An object of the present invention is to provide an improved electric fuel pump system which is simple, low in cost and which insures no pump discharge when the engine served stops.

A feature of the present invention is a fuel pump system having an engine starter and an electric fuel pump adapted to be connected in parallel to a voltage supply source such as a battery during engine starting, the system also including a temperature actuated switch arranged automatically to shift the pump voltage supply to the generator circuit of the engine when the latter begins to run. Another feature is a fuel pump system in which normally closed contacts of a temperature actuated switch are caused to open upon failure of an engine generator circuit thereby to terminate the discharge of fuel by the system to the engine.

The above and other features of the invention will now be more particularly described in connection with the accompanying drawings and then pointed out in the appended claims.

In the drawings:

FIGURE 1 is a diagrammatic view of an electrical fuel pump system in which the present invention is embodied; and

FIGURE 2 is a perspective and enlarged view of a temperature actuated switch employed in the circuit of FIG- URE 1.

FIGURE 1 of the drawings depicts a fuel pump circuit for an automobile engine, the'latter not being disclosed and contacts involved being set for engine starting. It will be understood, however, that the engine is arranged conventionally to drive a generator 10 which is grounded at 12 and the output of which is controlled by a generator relay 14, all of which is conventional. The usual engine starter motor 16 is employed and this motor is grounded at 18. A battery 20 serves as the voltage supply source and is shown grounded at 22. The starter motor is controlled by a relay 24 connected in the circuit between the battery 20 and the starter motor 16. An electrically operative pump is depicted at 26 and this pump is grounded as at 28.

A temperature actuated switch is indicated generally at 36, its construction being obvious in the view presented in FIGURE 2. A dielectric or plastic support member is shown at 32. This member is pierced by a terminal bolt 34 which serves to retain one end of a flexible metallic contact arm or plate 36 in position. The terminal bolt also retains one end of a bimetallic reed or thermo-sensi- 3,029,801 Patented Apr. 17, 1962 tive element 38 in fixed position with an insulator sheet 40 interposed between the element 38 and the flexible arm 36. An intermediate portion of the bimetallic element 38 is encircled by a resistance coil 42, one end of which is grounded by means of a line 44. The other end of the resistance coil 42 is connected by a line 46 to the battery through the starter relay 24. The free end or" the bimetallic element 38 integrally bears a tab 48 which extends through a slot 50 in one end of a C-spring 52. The other end of the C-spring is arranged to pivot on a tab 54 integral with the arm 36 and extending into a rectangular opening 56 formed in the arm 36, this being a conventional snap-over arrangement for switches. The free end of the flexible arm 36 bears two contacts 60 and 62. Flexing of the arm 36 will cause the tab 48 to move into or out from the opening 56 as the contacts 60 and 62 move in a path intersecting two fixed contacts 64 and 66. The contact 64 is supported by a fixed bracket 68 and the contact 66 is in a fixed position with no support therefore being shown in the drawings. The switch construction is such that the contacts 60 and 64 are normally closed and the contacts 62 and 66 are normally in open relation. The bracket 68 and a line 70 serve to connect the contact 64 with the generator 10 through the relay 14. The contact 66 is connected by a line 72 to the line 46, the latter also serving to supply current by way of a line 74 to the starter motor 16.

The terminal bolt 34 is connected by a line 76 to the pump 26.

As stated above the purpose of the system is automatically to prevent the electric pump from operating when the engine which the pump is serving is not operating. FIGURE 1 shows the contacts 62 and 66 as set for starting, i.e., not in their normally open engine operating positions. In operating the system, the starter relay 24 is closed as a first step to be undertaken to operate the starter motor 16. In so doing, the resistance coil 42 is energized causing the bimetallic element 38 to be heated and thereby then effect the second step to tilt the C-spring 52 and snap the switch 30 to the position shown in FIG- URE 1. This closure of the normally open contacts 62 and 66 closes the circuit to the electric pump. The pump is therefore connected in parallel with the starter motor during the engine cranking cycle.

When the engine starts and runs to operate the generator, the starter relay 24 opens, thus deenergizing the resistance coil 42. The bimetal reed 38 cools and by overcenter interaction with the C-spring 52 causes the flexible arm 36 to snap upwardly thereby placing the contacts 60 and 64 in their normally closed relation. The snap action of the switch 39 insures continued running of the pump during the transition period between cranking and normal positions of the contacts in the switch. The overcenter action of the switch takes place in a small fraction of a second although an engine could operate often up to a minute on fuel present in a conventional carburetor float bowl.

With the contacts 69 and 64 in their normally closed positions, the fuel pump 26 is energized by the generator circuit and if the engine and its generator should stop, the pump will automatically stop for lack of current. It should be noted that electrical energy for the entire system is used only during the cranking cycle to operate the thermo-sensitive switch 30. During normal running of the engine there is no electrical energy used except by the pump.

I claim:

1. An electric fuel pump system for an internal combustion engine, said system including a thermostatic snapover switch having normally closed contacts, normally open contacts and a bimetallic element positioned to control said contacts, a resistance heating element associated With said bimetallic element, a source of current for starting said engine, a generator adapted to be operated by said engine, an engine starter motor, the latter and said heating element being connected in parallel to said source of current, an electric fuel pump for said engine connected in series with said normally open contacts to said source of current, and said generator being connected through said normally closed contacts to said fuel pump.

2. An electric fuel pump system for an internal combustion'engine, said system including a thermostatic snapover switch having normally closed and normally open contacts and a bimetallic element positioned to control said contacts With the aid of an over-centering C-spring, a resistance heating element associated with said bimetallic element, a source of current for starting said engine, a generator adapted to be operated by said engine, an engine starter motor, the latter and said heating element being connected in parallel to said source or" current, an electric fuel pump for said engine connected in series with said normally open contacts to said source of current, said generator being connected through said normally closed contacts to saidfuel pump, and the arrangement being such that momentary energizing of said engine starter motor and heating element will eflect subsequent snap-over action of said switch to deenergize said heating element and close said normally closed contacts whereby said pump is driven by current from said generator.

References (Zited in the file of this patent UNITED STATES PATENTS 2,272,021 Ricke Feb. 3, 1942 2,496,135 Sedwitz Ian. 31, 1950 2,504,670 Everest Apr. 18, 1950 2,609,809 Parker Sept. 9, 1952 2,912,595 Kehm et al. Nov. 10, 1959 2,949,906 Voigt Aug. 23, 1960 2,988,079 Voigt June 13, 1961

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