US1831823A - Gas electric drive control - Google Patents

Description

Nov. 17, 1931. A. w. POPE, JR

GAS ELECTRIC DRIVE CONTROL Filed July 21 1926 Patented Nov. 17, 1931 UNITED STATES PATENT OFFICE ARTHUR W. POPE, JR OF WAUKESHA, WISCONSIN, ASSIGNOR TO WAUKESHA MOTOR 00., OF WAUKESHA, WISCONSIN,

A. CORPORATION OF WISCONSIN GAS ELECTRIC DRIVE CONTROL Application filed my 21,

My invention relates to drive control in vehicle propulsion systems in which a current generator coupled to the vehicle internal combustion engine supplies current for driving motors usually mounted on the vehicle driving axle.

With the driving motor positively connected to the drivingaxle of the vehiclefthe motor-speed varies with the vehicle speed,

and the voltage required to maintain a given power input to the motor increasesas the vehicle speed increases, and in order to obtain higher voltage for ofi'setting the motor counter electro-motive 'force it is necessary to run the generator and engine faster. The faster a motor is run, the higher will be the voltage required to maintain the power input and proper propulsion of the vehicle. It is this variable load on the generator caused by the variable vehicle speed which has caused the mostdifliculty in the operation of gas electric drive systems.

It is the object of my invention to overcome these difliculties by controlling the generator characteristics by a speed sensitive governor driven by the vehicle engine so that a predetermined fixed engine and generator speed will be maintained regardless of variations in the line resistance caused by change of vehicle speed.

In the drawings:

- Figure 1 is a diagramof the motor driven generator governor and the generator and the variable resistance therefore actuated by the governor, and associated parts.

Figure 2 is a diagram of the throttle control valve of the engine and the engine driven governor therefor and associated parts, the

v manually operated throttle valve being also shown.

The engine E has the intake manifold l with which is connected a carbureter C having the throttle valve 2. The throttle lever 3 is connected by rod 4 with the foot lever 5 In the intake manifold 1 is the governor throttle valve 6 controlled by the engine governor A. This governor structure may be of any well known type. As shown it comprises the bell crank weight levers 7 and 8 pivoted on the bracket 9 carried by one of the engine 1926. Serial N0. 123,970.

shafts, in this case, the cam shaft 10. The levers at their inner ends cooperate with an abutment 11 connected with the lever 12 of the governor throttle valve as by means of a rod 13, the adjustable governor spring 14 being shown connected with the end of the lever to resist closure of the valve 6 which normally is wide open. As is well understood in the art, the engine governor automatically controls the fuel supply to the engine from the carbureter and tends to keep the engine running at a constant speed.

The engine is directly coupled to the generator G to rotate the armature 15. Extending from the generator commutator brushes or terminals 16 and 17 is the external circuit 18 in which is included a series field winding 19, the driving motors M being connected with the external circuit in series, in parallel, or in series-parallel arrangement and are positively connected to the driving axle of the vehicle to be propelled.

The characteristic or output determining elements of the generator include, besides the series field winding 19, the shunt field winding 20 and an adjustable field resistance 21. I may also provide a tickler or excitation field Winding 22. The field resistance 21 is subdivided by a plurality of contacts 23 to be engaged by a contact arm 24 pivoted at 25. A manually operable setting lever'26 is pivoted at 27 and has a contact spring 28 for cooperation with a contact or terminal segment 29. One terminal of the shunt field winding 20 is connected with the generator terminal or brush 16 and the other end of the winding is connected by conductor 30 ,with the segment 29. A conductor 31 electrically connects the levers 26 and 2 1 and the outer terminal of the resistance 21 is connected by conductor 32 with the generator brush or terminal 17. By movement of the lever 24 along the resistance contacts 23 the resistance of the shunt field circuit is adjusted.

The tickler circuit includes a battery 33 in series with the tickler field 22 and the end of the circuit terminates in flexible contacts 34 and 35 which normally keep the tickler circuit open but which are located adjacent to the setting lever 26 to be brought into gagement when the lever 26 is moved toward the segment 29, being however, electrically disconnected from the levers.

In accordance with my invention I provide a generator governor B for operating the resistance contact lever 24 to control the resistance of the generator field circuit. This governor, like the engine governor A may be of well knownconstruction, it being shown as comprising the weight levers 36 and 37 pivoted on a frame 38 secured on the cam shaft 10. of the engine,'the 'inner ends of the leversengaging the abutment 39 at the end ofl a rod 40 which is connected to the resistance lever 24 a distance inside of the lever pivot point 25. Between the extension 41 of the setting lever 26 and the resistance lever 24 is connected the generator governor spring 42 which resists the pull of the rod 40 to move the lever 24 in resistance reducing direction. As before stated, the hand lever 26, by engaging with the segment 29 serves to close the shunt field circuit. The lever serves also to adjust the tension of the spring 42, and during the normal or open position-of the hand leverthe spring is at maximum tension but as the lever is swung to the left the tension of the spring is reduced.

Before the operator propels the vehicle, he first starts the engine in the usual way and opens the engine throttle 2 wide so that the engine can come up to governed speed without load, the generator running idle. Having started the engine the operator swings the setting lever 26 just far enough to make electrical contact with the segment 29. This is the low torque or low speed position and by this starting movement of the lever the shunt field circuit of the generator is closed and the contacts 34 and 35 .are also engaged to close the ticklers circuit. The tickler field winding excites or magnetically primes the generator and also keeps the generator from losin its magnetic field at low speed when the s unt field is very weak.

When the engine is'started the engine governor operates to control theintake valve 6 and the generator governor B tends to swing the resistance lever 24. However, the initial movement of the setting lever 26 is insuf ficient to relieve the tension of the spring 42 sufliciently to allow any material movement of the resistance arm 24 by the generator governor and so practically all of the resist.

ance 21 is included in the shunt field circuit during the low torque position of the setting lever. In this low torque position the engine will be held by the generator to a speed at which the engine develops its maximum poweg regardless of what the vehicle speed may e. V.

By moving the setting lever farther along the segment 29 the tension of the enerator governor spring 42 is reduced and t e ener- ,at constant speeds it is desirable to reduce the engine speed as much as possible and this is accomplished by moving the setting lever to thehigh torque position. For accelerating or hill climbing, when the maximum output of the engine is desired, the lever willbe set in the low torque position. For each position of the setting lever and corresponding tension adjustment of the spring 42, the generator governor B will automatically adjust the generator field resistance for the desiredoperating condition, and for each position of the lever there is therefore a. definite fixed speed determined for the engine regardless of vehicle speed or throttle opening, that is,

for any throttleopening great enough to permit this engine speed with the generator controlin the minimum torque position.

.All that the operator needs to do is to set the lever 26 for theautomatic establishment by the generator governor of the desired running' condition, and then operate the foot control throttle lever 5, the operation of this throttle control lever permitting reduction in engine speed below the governed speed determined by the engine governor A. In other words, the operator sets thelever 26 for the practical operation of the vehicle under the existing conditions and he operates the foot throttle lever 5'to vary the speed of the engine as desired, but only up to the governed maximum speed. With the establishmentof desired generator characteristics he runs the vehicle faster or slower as desired. The change in engine speed automatically controls, through the generator governor B, the strength of the generator eld and consequently the generator output to the vehicle motors and all this is automatically performed without depending on the personal element. As the vehicle speed and that of the motors increases, and the engineincreases'its speed due to the increased resistance in the generator external circuit, the generator governor speed and pull will be increased and thefield resistance correspondingly reduced to hold the generator pressure normal. I

An important feature and advantage of my invention is that the generator and engine can be brought up t6 speed before applying the load. This will give more "rapid acceleration of the vehicle because the inertia of the generator and engine .does not have to be overcome.

I have illustrated'my invention, by we. of example. as applied to an internal com ustion engine of the aspiration type. a. In its broader aspects, however, my invention is capable of being used with other types of engines, including injection engines. ccordingly, the term gas-electric drive as used in the descriptive matter of the specification and the claims is to be construed broadly and as covering the use of my invention with any type of engine with which it is capable of being used, except in such instances as this term is necessarily used in its restricted sense. Having described my invention, I claim as follows 1. In a gas-electric drive system, the combination of an internal combustion engine, a governor therefor, a manually controllable throttle for the engine, a generator driven by the engine, a generator governor operated by the engine to control the generator field circuit, a governor spring for said generator governor, and a hand lever controlling the tension of said spring.

2. In a gas-electric drive system, the combination of an internal combustion engine, an engine governor therefor,-a manually controllable throttle for the engine, a generator driven by the engine, a generator governor driven by the engine to control the generator field, a regulating spring for the generator governor, setting mechanism for setting the tension of said spring, and propulsion motors receiving current from said generator.

3. In a gas-electric power unit, the combination of an internalcombustion engine, a generator driven thereby, a field circuit for said generator, a resistance for said field circuit, a tickler circuit for the generator, a governor driven by the engine and connected to control said resistance, and manually operable means for modifying the action of said governor and for controlling the opening andclosure of said tickler circuit.

4.. In a gas-electric power unit, an internal combustion engine, a constant speed gov: ernor for said engine, a separate manual throttle control for the engine permitting reduction of the engine speed below governed speed, a generator driven by the engine,-a separate governor driven by the engine and connected to control the generator characteristics to thus regulate the load on the en- Y 211108 Il'OlIl maximum gine, a spring for said generator governor, and a manually controlled lever for regulating the tension of said spring.

5. In combination in a gas-electric drive, an engine with a tor driven by the engine, a variable generator field resistance, an electric motor driven by the generator, a governor driven by the engine, and means actuated by the governor and acting to vary the generator field resistto minimum and vice 'ersa for a predetermined narrow range 1 engine speed and inversely as the engine speed, whereby the generator excitation is throttle, an electric generavaried thus varying the load on the engine and maintaining the engine speed within certain predetermined limits independently of throttle position of resistance of the motor circuit.

6. In combination in a gas-electric drive, an engine, a shaft driven by the engine, an engine governor on said shaft, an electric enerator driven by the engine and having a variable field resistance, a generator governor on the shaft, and means actuated by the generator governor for varying the field resistance of the generator inversely as the engine speed.

7. In combination in a gas-electric drive, an engine, a' shaft driven by the engine, an engine governor on said shaft, an electric generator driven by the engine and having a variable field resistance, a generator governor on the shaft, means actuated by the generator governor for varying the field resistance of the generatorinversely as the engine speed, a throttle for the engine, and means for operating said throttle independently of the governors.

8. In combination in an engine, means for varying to the engine, an electric generator driven by the engine, a variable generator field resistance, an electric motor driven by the generator, a governor driven by the engine, and means actuated by the governor and acting to vary the generator field resistance from maximum to minimum for a predetermined narrow range in engine speed and inversely as the engine speed, whereby the generator excitation is varied thus varying the load on the engine and maintaining the engine speed within certain predetermined limits under wide variation of fuel supply to the engine.

In witness whereof, I hereunto subscribe my name this 15th day of July. 1926.

ARTHUR W. POPE, JR.

electric drive, an the supply of fuel

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