US2622576A

US2622576A - Two-speed engine governor

Info

Publication number: US2622576A
Application number: US193402A
Authority: US
Inventors: August W Rickenbach
Original assignee: Avco Manufacturing Corp
Current assignee: Avco Manufacturing Corp
Priority date: 1950-11-01
Filing date: 1950-11-01
Publication date: 1952-12-23
Anticipated expiration: 1969-12-23

Description

Dec. 23, 1952 A. w. RICKENBACHY 2,576

TWO-SPEED ENGINE GOVERNOR Filed Nov. 1, 1950 INVENTOR. AUGUST M. RIG/(ENBACH ZQMQ ATTORNEY.

Patented Dec. 23, 1952 UNITED rates ears T QEFICE T'WO-SPEED ENGINE GOVERNOR 7 Claims.

The present invention relates to governors and has particular reference to a mechanism for use with a fly ball governor which is arranged to control the operation of an associated engine at either of two predetermined operating speeds.

Although it may be used with purely mechanical loads, such as pumps, the herein disclosed govrnor mechanism has particular utility when used in conjunction with a stand-by electric power plant, especially an engine-generator set which must be operated for protracted periods during which energy may be drawn at varying rates from the generator. In applications of this type an engine-generator set frequently must operate at constant speed and a fly ball governor is often provided to hold the speed constant regardless of the load which is imposed. Since the set must be capable of producing full load output, the constant speed of operation for which the governor must be adjusted must be close to the full load speed of the engine with the result that the set may operate for long time periods at full load speed but with a very small power output due to the small load on the generator during these periods'. This condition may foster rapid wear of the engine which is highly undesirable since the life span of the engine may be reduced despite the fact that the set is often operated considerably below full load output.

It is, therefore, an object of the present invention to provide for use on engine-generator sets a two-speed governor which is designed to regulate the engine speed so that full load power may be produced during periods of large demand but the engine speed may be reduced to a low speed or idling level during periods when reduced loads or no load is imposed on the generator.

Since the power consumption of engine accessories, associated cooling fans, and related transmission units decreases as the engine speed decreases, overall operating efiiciency can be improved by restricting low load operation to low speeds. The herein disclosed governor improves overall efficiency in this way which is an important object of the present invention.

A preferred embodiment of the present'invention is disclosed herein and comprises a commercially available fly ball governor having a spring, opposing outward movement of the fly balls, the load of which may be varied to two predetermined values by a solenoid which is energize'd in accordance with the pressure within the intake manifold (hereinafter referred to as manifold pressure) of the engine being governed. Since the spring has two o-peratingloads, the fiy balls have to develop two di'iferent'values of centrifugal force to overcome the spring and decrease the throttle setting of the carburetor or other charge-forming device of the engine. In this way the engine is governed at two different operating speeds each of which is maintained whenever the engine intake manifold pressure is above or below predetermined values It is also an object of the present invention to provide a governor mechanism whichacts to increase the governed speed of an associated engine whenever theload imposed on the engine and the resulting governor action cause the manifold pressure to rise above a predetermined value.

Another object of the present invention is to provide a governor mechanism which will automatically reduce the speed of operation of an associated engine to the idling condition when the load on the engine is reduced or removed.

A still further object of the present invention is to provide a governor mechanism which is responsive in its operation to the intake manifold pressure of an associated internal combustion engme.

Another object of the present invention is to provide a governor for controlling a carburetor throttle valve which is in series with another hand operated throttle valve located between the carburetor and intake manifold of the engine.

The novel features that are considered characteristic of the invention are set forth inthe appended claims. The invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in conjunction with the accompanying drawing which shows diagrammatically the governor mechanism associated with the carburetor and a portion of the intake or induction manifold of the engine beinggoverned. Part of the governor mechanism is shown broken away and in section to facilitate the description of its operation.

The'present invention comprises a commercially available fly ball governor, generally designated l, which is driven directly by the governed engine (not shown) through a gear 2. The governor acts to control the positionof a throttle valve 3of a carburetor I; connected toand supplying a combustible mixture to an intake manifold 5 of an internal combustion engine. This engine may be used to drive any power consuming device, mechanical electrical; and may be used to particular advantage in drivihg D. C. and A. C. electric generators. v

A pressure switch, generally designate-d6, is in Communication with intake manifold 5 and controls the energization of a solenoid l which when energized moves a bell crank 8 of the fly ball governor to a raised position, indicated in phantom lines at 9. The pressure switch may incorporate a bellows l3 the interior of which is in communication with the engine intake manifold through interconnecting pipe line I I. When the pressure within the bellows exceeds a predetermined value, the bellows expands and closes an electric switch I2 which completes an electric circuit I3 and energizes solenoid 1 with current drawn from battery l4.

The fly ball governor itself may be any standard commercially available unit modified as needed to meet the requirements of the present invention. A typical governor of this type is manufactured by the Pierce Governor Company of Anderson, Indiana. Such a governor incorporates a yoke l5 secured for conjoint rotation to shaft is to which gear 2 is secured. The yoke carries a pair of pivotally attached fly balls I! which, during rotation of shaft I6, tend to diverge from its center line under the influence of centrifugal force in a manner well known in the art. The fly balls act on a thrust collar (not shown) which imparts a rotary movement to an Operating lever 18 and shaft is to which it is attached.

Throttle control arm 23 is secured to shaft [9 and may swing between the full and phantom line positions shown. A connecting link 2| transfers the motion of this arm to the throttle valve 3 which is held in a relatively open position when arm 20 is in its full line position and is held in a relatively closed position when the arm is in the position indicated by phantom lines.

A tension spring 22 is stretched between arm 20 and an adjustable mounting eye 23 which is threadedly secured to one arm of bell crank 8. Fly balls I! must overcome the tension of spring 22 before clockwise rotation can be imparted to shaft [9, which rotation results in closing throttle valve 3.

Bell crank 8 has an outstanding arm which is connected by link 24 to axially movable plunger 25 of solenoid T. Plunger 25 is moved from its full line to its phantom line position whenever solenoid I is energized by the closure of electric switch 12. The movement of the solenoid plunger imparts rotation to bell crank 8 about its pivot pin 26 and stretches spring 22. As will be described more fully hereinafter, the phantom line position of the plunger prevails whenever the engine being governed is subjected to a load. It is therefore to be noted that, when the engine is operated under load, spring 22 is in a relatively stretched position in comparison to a less stretched or tensioned position prevailing during periods when the engine is idling and not carrying any substantial load.

A second throttle value 21 is in serious with throttle valve 3 and is controlled by an extensible flexible cable 28 which may be moved manually to adjust throttle valve 21 during periods when the engine is being initially started. When the engine is at rest, solenoid 1 will not be energized, fly balls I! will be at rest and throttle valve 3 will be held in an open position under the influence of spring 22 acting on arm 20. When the engine is to be started, an operator manually opens throttle valve 21 slightly and starts the engine in a conventional fashion. Since valve 21 is in a relatively closed lit 4 position, the engine cannot gain speed sufii ciently for the fly balls I! to overcome the tension of spring 22 and as a result valve 3 re mains in a full open position.

When the engine has been warmed up and is to be placed under governor control, the operator opens valve 21 fully. As this valve is opened, the engine rapidly ains speed and the fly balls overcome the tension of spring 22 and rotate lever 20 in a clockwise direction to close valve 3. Spring 22 has a predetermined tension which can be overcome when the fly balls attain a relatively low rotational speed, such as 1300 R. P. M., which for most engines is a rather fast idlin speed. If for any reason the engine should tend to exceed 1300 R. P. M., the fly balls impart additional rotation to shaft I9 and close valve 3 until a new equilibrium condition prevails slightly above 1300 R. P. M. Conversely, should the speed tend to fall off for any reason, spring 22 will overcome the centrifugal force of the fly balls and open valve 3 to re-establish the idling speed of the engine.

During the idling period, the charge supplied to the engine is severely throttled by valve 3 with the result that a very small absolute pressure, or in other words a sizable vacuum, exists in manifold 5. This is a natural operating condition for an unsupercharged engine.

By virtue of interconnecting pipe line H, bellows I0 of pressure switch 6 is likewise subjected to a relatively large vacuum with the result that the bellows is collapsed allowing electric switch l2 to remain in its open position. Thus, the engine will continue to idle at 1300 R. P. M. under the conditions just described until a load is imposed on its output shaft.

The immediate response of the engine to the imposition of a load is a decrease in its rotational speed. As its speed decreases, the centrifugal force of the fly balls also decreases with the result that spring 22 acts to move shaft I9 counterclockwise thereby opening valve 3. The combination of a relatively wide open throttle valve and a low engine speed permits the manifold pressure to rise rapidly towards atmospheric pressure. As a result bellows I0 expands until electric switch [2 is closed completing the circuit l3 and energizing solenoid I. Plunger 25 is moved to its upper position shiftng bell crank 8 to position 9 and simultaneously increasing the tension load of spring 22 on arm 20 to a higher predetermined value. The increased spring load on arm 20 immediately opens valve 3 to its fullest extent with the result that the engine, having a wide open throttle, rapidly accelerates and the fly balls gradually develop sufilcient centrifugal force to overcome the increased tension of spring 22. However, this increased tension can only be overcome at a much higher rotational speed of the fly balls, such as 2300 R. P. M., which is a typical full load operating speed for an internal combustion engine. When this speed has been attained, the fly balls,

overcoming spring 22, rotate shaft [9 clockwise and gradually close valve 3, thus holding the engine speed to substantially 2300 R. P. M. and adjusting the valve as required to maintain the speed of the engine regardless of what load is imposed. As valve 3 is opened and closed while the engine is being held at a uniform speed, the pressure in the induction system rises and falls. However, the pressure never falls while the engine is under load to a value sufficiently low to permit bellows ID to collapse and switch 12 to open.

When the load is removed from the engine, the engine rapidly tends to overspe'ed and fly balls I! rapidly act to close valve 3. As the valve continues to close, the pressure Within the en'- gine induction system rapidly falls until bellows l collapses and switch I2 is opened. The resulting de-energization of the solenoid permits outward. movement of plunger 25 and a decrease in the tension of spring 22. This decrease in spring force, combined with the excessive speed of the fly balls, acts immediately to close valve 3 still further, thus throttling the engine until the speed again falls to 1300 R. P. M- at which speed the engine is maintained in anticipation of another application of load.

When the engine is to be shut off, valve 21 is manually shifted to the closed or idling position. As this valve gradually closes, the engine is excessively throttled, the speed drops oif, and the fly ball governor gradually acts to open valve 3 to its fullest extent at which condition the engine may be shut off.

If it is considered desirable, the engine may be shut off while it is held in the idling condition by the governor rather than by the hand operated throttle valve 21.

From the foregoing description it will be apparent that a very simple two-speed governor has been provided and that this governor will hold the speed of an internal combustion engine alternately and automatically to either idling or full load commensurate with the load on the engine. It will also be apparent to those skilled in the art that the operation of the governor is perfectly stable and that the only deviation encountered in the regulated speed is that which is normally incidental to fly ballgovernors.

It has been found advisable to provide an operating differential for pressure switch 6' so that solenoid I is energized and de-energized at slightly different values of manifold pressure. By providing such an operating differential the solenoid is prevented from erratically switching the governor between high and low speed settings, such as might otherwise occur during slight fluctuations from the operating pressure of the switch.

Pressure switch 6 is a conventional commercially-available unit. A switch which lends itself readily to use in the subject invention is made by Penn Controls, Inc., Goshen, Indiana, and is identified as their type 155BVO1 vacuum control. This switch is adjustable both with respect to its particular operating range and the differential between its opening and closing pressure; however, these adjustments are not material in the present invention and have not been illustrated in the drawing which is merely a diagrammatic showing. For instance, it will be noted that electric switch l2 incorporates an actuating arm 29 which is pivotally interconnected with a spring loaded toggle 30, movement of the actuating arm resulting from a slotted interconnection 3| with bellows l0. By virtue of the overcenter toggle and the lost motion of the slotted connection, the construction produces an operating differential between the opening and closing pressures.

Such an operating differential is also important for those engines wherein the valve timing is such that the manifold pressure at a given output at high speed is below the manifold pressure corresponding to this same power output at low speed. For engines having this type characteristic, a small operating differential is required to prevent the governor mechanism from hunting between the high and low speed governor setting when the absolute manifold pressure nears that value necessary to actuate switch 6. g

The governor mechanism has been described hereinbefore with particular reference to operation at high speed under load and operation at a low speed while idling or under no load. Itis obviously possible that this same governor can be used to regulate enginespeed between a high load and a lower load condition. In other words the governor can maintain an engine speed such as 2200 R. P. M. for operation at powers over 25% of the rated power and can maintain a lower speed for operation below this power output. Thus, it is possible by the use of the present governor to hold the engine speed at a relatively low value, for example 1300 R. P. M., and to maintain this speed until a preselected pressure level within the manifold, corresponding to a pr'e'de termined percentage of the availablepower at this speed, is attained. When this preselected valueis attained, the solenoid is energized and the engine throttle is adjusted for the same power output but at a higher governed speed. Increased loading of the engine beyond this point causes a; further increase of manifold pressure. Thus, the engine continues its operation at the higher speed and solenoid 1 remains energized.

As the load is gradually removed from the engine the manifold pressure drops to another predetermined value, below the first predetermined value by the amount of the operating differential, at which solenoid 1 is deenergized and the governor acts to reduce the engine speed to a lower value as has been explained.

It has been found desirable to use' an operating difife'rential of at least 3%; inches of mercury for pressure switch 6 to prevent the two speed mechanism of the governor from hunting between the high and low speed settings under'all conditions of operation. For instance switch 6 usually energizes solenoid 1 at an absolute manifold pressure of 17 inches of mercury and de-energizes the solenoid at an absolute manifold pressure of 12.5 inches of mercury.

Having described a preferred embodiment of my invention, I claim:

1. In a governor mechanism for an internal combustion engine having an induction manifold, a governor having revoluble fly balls and a spring opposing the centrifugal action of said fly balls, a solenoid the position of which controls the total load of said spring, and a pressure switch responsive to the induction manifold pressure of the engine, said switch energizing said solenoid to change the load of said spring when the pressurewithin the induction manifold of the engine rises above a predetermined value.

2. In a governor mechanism for controlling an internal combustion engine having an induction system which is supplied with a combustible mixture by a carburetor, a governor, a carburetor throttle valve controlled by said governor, a spring opposing the action of said governor while closing said throttle valve, a solenoid for increasing the load of said spring when energized, and means in communication with the engine induction manifold for energizing said solenoid when the manifold pressure attains a predetermined value.

3. A governor mechanism for an internal combustion engine having a carburetor connected to an induction system comprising a governor, a

throttle valve in the carburetor which is adjusted by said governor to regulate the engine speed, a spring the force of which acts at all times to Open said throttle valve, means in communication with the induction manifold of the engine, said means having a movable member which is shifted to predetermined positions corresponding to predetermined pressures within the manifold, said member biasing said spring whereby the governed speed established by said governor is changed in response to manifold pressure.

4. A governor mechanism for an internal combustion engine having an intake manifold and a charge forming device comprising a centrifugal governor driven by the engine, said governor adjusting the setting of the charge forming device to govern the speed of the engine, resilient means modifying the action of the governor in its adjustment of the charge forming device, a solenoid having a movable member which biases said resilient means in the course of its movement, and pressure sensitive means in communication with the intake manifold, said pressure sensitive means energizing said solenoid when the pressure within the manifold rises above a predetermined value.

5'. A two-speed governor mechanism for use in conjunction with an internal combustion engine having an intake manifold and a charge forming device comprising a governor driven by the engine for adjusting the charge forming device to regulate the engine speed, resilient means against which the governor acts in governing the engine speed, a solenoid for biasing said resilient means when energized, and a pressure sensitive element in communication with the engine intake manihaving an intake manifold and a charge-forming device comprising a centrifugal governor driven by the engine for adjusting the setting of the charge-forming device to regulate the engine power and speed, a spring against which the governor acts in governing the engine speed, a solenoid for biasing said spring when energized and a pressure sensitive element in communication with the engine intake manifold, said element comprising an electrical switch and pressure sensitive means for opening and closing said switch in response to predetermined manifold pressures, the pressure at which said switch is closed bein above the pressure at which it is opened, closing of said switch energizing said solenoid whereby said spring is biased and the governed speed of said engine is shifted to a higher value from that maintained by the governor when the solenoid is de-energized.

7. A governor mechanism for an internal combustion engine having a charge-forming means connected to an induction system comprising a governor, a throttle valve in the charge-forming means adjusted by said governor to regulate engine speed, resilient means against which said governor acts, and means in communication with the induction manifold of the engine, said means having a movable member which is shifted to predetermined positions corresponding to predetermined pressures within the manifold, said member biasing said resilient means whereby the governed speed established by said governor is changed in response to the manifold pressure.

AUGUST W. RICKENBACH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,047,702 Pfeil July 14, 1936 2,204,492 Heintz June 11, 94