US2218846A - Control for electric fuel pumps - Google Patents

Description

Oct. 22, 1940. v A. c. KORTE Er AL 2,218,846

CONTROL FOR ELECTRIC FUEL PUMPS Filed Nov. 16, 1939 INVENTORS T ALFRED C. KoRTE KENNETH LANNERI ATTORNEY Patented Oct. 22, 1940 UNITED. STATES PATENT QFFICE CONTROL FOR ELECTRIC FUEL PUMPS Application November 16, 1939, Serial No. 304,746

12 Claims.

This invention relates to control means for electrically driven motor vehicle accessories and more particularly to control means for electrically driven fuel pumps.

It is essential to the satisfactory operation of motor vehicle engines equipped with current popular type carburetors, that fuel pumps used in connection therewith operate to supply fuel during all conditions of engine operation and during cranking to start the engine. It is also essential to safety to insure that the pump does not operate at any other time. Fuel supply to the carburetor during cranking is necessary even though the carburetor may have a constant level chamber of sufficient capacity to permit starting under normal conditions, for the reason that the supply in this chamber is frequently substantially depleted by evaporation, and further, this chamber being limited in size for practical reasons is usually of insufficient capacity to take care of difficult starting.

In the interest of safety, fuel should not be supplied to the carburetor while the engineis inoperative, for the reason that a defective or sticking carburetor float mechanism or leaky inlet valve may permit overflowing of the constant level chamber, thereby spilling liquid fuel into the engine induction system causing difficult starting, and which in sufiicient quantities could cause the engine to be wrecked upon subsequent cranking. Further, highly inflammable fuel overflowing from the constant level chamber through the vent onto an adjacent hot exhaust manifold is extremely hazardous.

It is the primary object of this invention to provide novel and fool proof means for controlling electrically driven motor vehicle fuel pumps in accordance. with requirements as heretofore set forth.

The manner in which this object and further objects and advantages which become apparent are accomplished are set forth in the following description and accompanying drawing in which like numerals in the various modifications refer to like parts.

Referring to the drawing Figs, 1, 2 and 3 are diagrams of three modifications of the present invention.

Referring to the drawing, numeral l indicates an electrically driven centrifugal type fuel pump, similar to the pump disclosed in our co-pending application, Serial No. 291,588. However, the use of this particular pump is not essential to the present invention and the use of any suitable electrically driven fuel pump is contemplated. A

storage battery is indicated at 2, and a conventional automotive type generator adapted to be driven by a motor vehicle engine (not shown) is indicated at 3. A charging lead 22 from the generator to the storage battery having a conventional reverse current relay l5 interposed therein is indicated. A starting motor provided for cranking said motor vehicle engine is indicated at 4. A manually operated switch generally indicated at 5, having a blade 6 which is normally held in the position shown by the spring I is provided. The switch 5 is further provided with contacts 8, 9 and Hi.

In the arrangement shown in Fig. 1, the fuel pump and generator are electrically connected when the switch blade 6 is in the position shown, by lead I I, contact l0,blade 6 and lead l2. A lead l3, contact 8 and lead I! connects the fuel pump 1 to the battery when the switch is depressed causing the blade 6 to contact with 8. Current for energizing the starting motor is supplied from the storage battery through lead l3, contact 8, blade 6, contact 9 and head ll when the switch 5 is depressed.

The operation of the device shown in Fig. 1 is as follows:

Depression of switch 5 will energize starting motor 4 to crank the engine. At this time current is also supplied by the battery to the fuel pump through leads l3 and [2. After the engine has been started the switch is released and returns to the position as shown by reason of spring 1. Thereafter, during normal operation of the engine, electrical energy for operation of the fuel pump is supplied by the generator which is driven by the engine. The fuel pump will, therefore, cease to operate when the engine becomes inoperative. It is assumed in this arrangement that the generator 3 in Fig. 1 is so constructed and geared with respect to the engine that its output during the lowest engine operating speed is sufficient to operate the electric fuel pump.

It is a fact, however, that in most present day vehicles, the generators furnished therewith do not supply suilicient current for the operation of an electric fuel pump during the lower engine speeds. The speed-voltage curve of conventional self-excited shunt wound automotive generators, rises very little from zero speed up to a critical speed, whereafter the voltage increases very sharply and the curve rises almost vertically to the regulated maximum voltage. This critical generator speed in most cases constitutes an engine speed of approximately 550 R. P. M., or a vehicle speed of about M. P. H.

her. With separate field excitation the generator Referring to Fig. 2 which discloses a second form of our invention, we have herein overcome this difficulty without constructing a costlier generator, by providing separate excitation of the field winding ll! of the generator 3a. This provision constitutes a storage battery circuit comprising a lead It, a manual switch it, a lead i'i, field winding l8, lead 20, voltage regulator 2i and ground m. The manual switch i9 may be the conventional ignition switch through which ignition devices (not shown) are connected. The voltage regulator 2| is of conventional type and functions to control generator output voltage by varying the field strength in a well known manspeed voltage curve rises from zero to the regulated maximumvoltage in approximately a straight line. As the regulated maximum voltage is reached at approximately the same speed in either form of field excitation, it will be seen that a substantial increase in output is gained at speeds below 20 M. P. H. vn'th separate field excitation. It will be understood of coursethat this gain is paid for with battery energy and, therefore, the total energy of the system is not increased. But rather, this arrangement provides a means dependent on engine operation 'for transmitting energy from the battery to the fuel pump at the lower speeds by induction, and therefore, functions as a control device.

Apart from the manner of field excitation the device shown in Fig. 2 functions similar to the device shown in Fig. i. y

In the third form of our invention as disclosed in Fig. ,3, a solenoid operated control switch 23 is provided and interposed in a lead ib--2 i2*5- i@ti2 from the battery to the fuel pump.

The solenoid winding 26 of switch 23 is energized through lead 2?? by the generator. The winding 26 is grounded at 28.

The operation of this form of our invention is as follows:

Referring to Fig. 3, upon depressing the switch 5, the starting motor Q will be energized by the battery through lead ii3Ei-i i, thus cranking the engine. At this time current will be supplied to the fuel pump by the battery through lead i3-8@i2. After the engine has been started, the switch 5 is released and current will be supplied to the fuel pump from the battery through lead it--2d--2325i-Eii2 as long asthe engine continues to operate and drive the generator, which will energize solenoid 2d thereby holding switch 23 closed. The separately excited generator field is also used in this arrangement toinsure sumcient flow from the generator at low speeds to hold switch 23 closed. It will be understood that the switch 28 and also the conven- 1 tional reverse current relay iii are normally open, that is to say they are in a circuit breaking position except when suficien't current is passing through their respective actuating solenoid windings to close or hold them closed. It will be further understood that the reverse current relay i 5 is so calibrated as to be closed only when the generator output voltage is equal to or above that of the storage battery and that the automotive type generator herein considered reaches this output at a speed which approximates 20 M. P. H. vehicle speed.

We are aware that the present disclosure is subject to various modifications and we contemaaraeae plate the use of all which come within the scope of the appended claims.

We claim:

1.- In a fuel pump control system for internal combustionengines, an engine cranking motor, a source of power dependent on continuous en gine operation for driving-the fuel pump, a source of power independent of continuous engine opera- .tion for driving the fuelpump, and control means whereby the fuel pump is caused to be operated by said independent power source during the operation ofsaid cranking motor, and whereby the fuel pump is caused to operate by said dependent power source during normal. engine operation.

2. In a control system for electrically driven internal combustion engine fuel pumps, an electric engine cranking motor, an engine driven generator, a storage battery, an electric fuel pump motor, and a manually operated switch device capable of being moved to one position whereby said cranking motor and said fuel pump motor are energized by said battery and capable of being moved to second position whereby said fuel pump motor is energized by said generator.

3. In a control system for electrically driven internal combustion engine fuel pumps, an electric starting motor, an electric engine driven *generator, a storage battery, an electric fuel pump motor, and a switch device, said switch being movable to one position whereby said battery, said starting motor and said fuel pump motor are electrically connected, and yieldable means for normally urging said switch to another position whereby said generatpr and said fuel. pump motor are electrically connected.

- 4. In a control system for electrically driven automotive fuel pumps, an electric fuel pump motor, an internal combustion engine, a storage battery, and means controlled by said battery and dependent upon the operation of said engine for transmitting electrical energy to said fuel pump motor by induction for the operation thereof.

5. In a control system for electrically driven automotive fuel pumps, an interna combustion engine, an electrical fuel pump circuit comprising a storage battery, an electric fuel pumpmotor, and a normally open control switch, an electromagnet constructed and arranged to move said control switch-to a circuit closing position when energized, and means controlled by said battery and dependent upon the operation of said engine for energizing said electromagnet.

6. In a control system for electrically driven automotive fuel pumps, an internal combustion engine, an electrical fuel pump circuit, comprising a storage battery, an electric fuel pump motor and a normally open control switch, an electromagnet constructed and arranged to move said control switch to a circuit closing position when energized, and means controlled by said battery and dependent upon the operation of said engine for transmitting electrical energy to said electromagnet by induction.

- '7. In a control system for electrically driven automotive fuel pumps, an internal combustion engine, an electrical circuit comprising a storage battery, an electric fuel pump motor and a normally open control switch, a second electrical circuit comprising a generator controlled by said battery and arranged to be driven by said engine, and an electromagnet, said electromagnet being constructed and arranged to move. said control switch to a circuit closing pomtion when energized.

8. In a control system for electrically driven automotive fuel pumps, an internal combustion engine, an electric starting motor for cranking said engine, an electrically driven fuel pump for supplying fuel to said engine, a storage battery, an electrical circuit connecting said storage battery and said fuel pump, a normally open switch in said circuit, an electromagnet for closing said I switch, means dependent upon the operation of said engine for energizing said electromagnet, a branched circuit for connecting said starting motor and said fuel pump to said battery, and a switchfor opening and closing said branched circuit, said last mentioned switch being normally held in a circuit open position by yieldable means.

9. In combination, an internal combustion engine, a generator comprising a field winding and an engine driven armature, a storage battery and an electric fuel pump, a charging lead connectinggenerator having a field excited by said battery and an armature rotated by said engine, and a circuit comprising said fuel pump and said armature.

, 11. In a control system for electrically driven automotive fuel pumps, an internal combustion engine, a storage battery, a generator having a field excited by said battery and an armature rotated by said engine, a circuit comprising an electric fuel pump motor and said armature, a circuit comprising said storage battery and said fuel pump motor and switch means for alternately disconnecting said fuel pump from said battery and from said armature.

l2. Ina control system for electrically driven automotive fuel pumps, an internal combustion engine, an electric engine cranking motor, a storage battery, a generator having a field excited by-said battery and an armature rotated by said engine, a circuit comprising said cranking motor and said battery, a circuit comprising an electric fuel pump motor and said generator armature, a circuit comprising said fuel pump motor and said battery, and a switch device whereby said cranking motor and said .fuel pump motor can be simultaneously connected to said battery and said fuel pump motor disconnected from said armature.

' ALFRED C. KOR'IE.

mm LANNERT.

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