US3209613A

US3209613A - Hydraulic governors

Info

Publication number: US3209613A
Application number: US223875A
Authority: US
Inventors: Potter James Charles
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1961-09-21
Filing date: 1962-09-17
Publication date: 1965-10-05
Anticipated expiration: 1982-10-05
Also published as: GB973613A

Description

Oct. 5, 1965 J- c. POTTER 3,209,613

HYDRAULIC GOVERNORS Filed Sept. 17, 1962 FIG.2 T

United States Patent 3,209,613 HYDRAULIC GOVERNORS James Charles Potter, Chiswick, London, England, assignor to C.A.V. Limited, London, England Filed Sept. 17, 1962, Ser. No. 223,875 Claims priority, application Great Britain, Sept. 21, 1961, 33,7 98/ 61 2 Claims. (Cl. 74472) This invention relates toa hydraulic governor for controlling the rate of supply of liquid fuel to an internal combustion engine in response to variations in the speed of the engine, the governor being of the kind wherein a pump adapted to be driven by the engine is arranged to deliver fuel through a circulatory system, and wherein the pressure difference across an orifice or orifices in the system is caused to control the setting of means for regulating the supply of fuel to the engine.

In vehicles incorporating internal combustion engines adapted to drive the vehicle wheels through a variable speed gear, it is often required that the speed of the engine should be prevented from rising above a predetermined value whilst driving the wheels through relatively high gear ratios such, for example, as when direct top gear, and/or overdrive top gear is engaged, but when lower ratios are engaged, the engine should be capable of operating at a speed above the predetermined value to provide high torques for large loads.

1 The object of this invention is to enable this requirement to be met in a convenient manner with a governor of the kind specified.

According to the invention a hydraulic governor of the kind specified incorporates, in parallel with said orilice or orifices, a further orifice, and valve means for preventing fluid flow through said further orifice when a selected gear ratio, or selected gear ratios, are engaged.

In the accompanying drawings:

FIGURE 1 is a sectional view of one example of the invention and FIGURE 2 is a diagrammatic view showing how part of the example shown in FIGURE 1 can be operated.

FIGURE 3 is a diagrammatic plan view of the essential components of a motor vehicle to which the example is applied.

Referring to the drawings, there is provided a body part 1 having formed therein a plurality of

passages

2, 3, 4 and 5 these passages forming parts of a circulatory system through which liquid can flow under the action of a gear pump 6 adapted to be driven by the internal combustion engine. In the system is formed a cylindrical chamber 7 which communicates at one end with the passage 3 and at the other end with the passage 4. The chamber 7 contains a regulating piston 8 which is loaded by a spring 9, and from which extends a rod 10 having its outer end connnected to a lever 11, the latter being adapted to actuate the usual regulating means of the injection pump which supplies liquid fuel to the engine. Also between the circulating pump 6 and the chamber 7 is formed a second cylindrical chamber 12 which at one end is connected by the passage 2 to the delivery side of the pump 6, and at the other end is connected by the passage 3 to the corresponding end of the first chamber 7. The second chamber 12 contains a hollow piston 13 having in its end an orifice or orifices 14 through which the liquid from the circulating pump 6 can flow with an appropriate pressure drop which is a function of speed, and on the end of this piston rests the stem 15 of a control valve 16 which serves by cooperation with a seating at one side of a port 17 to control communication between the passages 3, 4 and thus to control the flow of liquid in the system. The valve 16 is loaded by a spring 18 which is contained within a hollow extension of the valve and the interior of another and coaxial hollow valve 19 which serves as a guide for the first valve, and which controls a by-pass between the passage 4 and the passage 5, the latter passage being in communication with the suction side of the pump 6. The by-pass above mentioned is formed in part by a passage 20 in which the by-pass valve 19 is slidably supported by longitudinal ribs 21 on this valve and in part by a chamber 22 between the last mentitoned passage and the passage 5. The by-pass valve 19 co-operates with a slotted skirt 23 at one end of the by-pass passage 20 to control communication between this passage and the passage 4, and this is loaded by the same spring 18 as the first valve 16, this spring tending to move the by-pass valve to its closed position. valve 19 against the action of the spring 18 is effected by a cam-like lever 24 mounted in the by-pass chamber 22, this lever being adapted to act on the adjacent end of the by-pass valve, and being operable by a lever 25 which is controlled by the driver. Also in parallel with the by

pass

20, 22 is arranged a variable choke consisting of a piston valve 26 which is slidable in a ported sleeve 27, and is loaded by a spring 28, the outer end of the valve being in contact with an adjustable abutment 29 on the above mentioned lever 11 which transmits movement to the regulting means of the fuel pump. The variable choke serves to control communication between the passages 4, 5.

The operation of the governor will now be described. When it is required to start the engine the lever 24 is set in a position such that the by-pass valve 19 is closed, the engine is then cranked and the circulating pump 6 causes liquid under pressure to pass through the orifice 14 of the hollow. piston 13 to one side of the regulating piston 8 and to move the latter, in opposition to its spring 9, to cause the fuel pump regulating means to be so actuated as to enable the maximum amount of fuel to be delivered by the pump. When the engine begins to rotate under its own power, the pressure acting on the underside of the piston 13 increases sufficiently to open the valve 16, thereby allowing liquid to pass to the other side of the regulating piston 8 and return to the suction side of the pump 6 through the

variable choke

26, 27. The consequent rise of pressure on that side of the regulating piston 8 assists the spring 9 to return the regulating piston to a new position of equilibrium, in which the rate of supply of fuel from the fuel pump is reduced to an amount corresponding to the idling requirements of the engine. The movement of the regulating piston 8 is simultaneously transmitted to the piston valve 26 of the variable choke to produce an increased opening thereof, and this action tends to oppose the change in position of the regulating piston. To obtain an increase of the speed of the engine, the cam like lever 24 is actuated by the driver so as to open the by-pass valve 19 and increase the spring pressure on the first valve 16, the amount of movement given to the cam like lever being dependent on the fuel requirements of the engine. This action causes the liquid pressure on the side of the regulating piston 8 remote from the spring 9 to be increased and that on the other side to be decreased, with consequent increase of the fuel pump delivery. When the speed of the engine has increased sufficiently to produce a pressure drop through the orifice or orifices 14 of the hollow piston 13 such as to cause the latter to open the control valve 16, the pressure in the system will drop sufficiently to allow the spring 9 to move the regulating piston 10 into a new position of equilibrium.

In carrying the present invention into effect there is provided in parallel with the orifice or orifices 14 a further orifice 30 which is formed in a passage 31. Also incorporated in the passage 31 is a valve 32 which is spring loaded towards a closed position and which is arranged Movement of the by-pass" to be opened when an electro-magnet 33 is energised. The electro-magnet is arranged to be energised under the control of a switch 34 operable by the gear shift lever 37 of the vehicle the lever being movable within a selector gate 36, and the switch being closed when selected gear ratios, such, for example as all gear ratios below the highest gear ratio are engaged. The selector gate 36 and gear shift lever 37 are associated with a multi-ratio gearbox 38 disposed intermediate an engine 39 and the drive axle unit 40, the latter carrying a pair of driven road engaging wheels 41 of the vehicle.

Conveniently the further orifice 30 is adjustable so that discrepancies between individual governors can be accommodated and it may comprise an axially adjustable rod 35 movable in a direction substantially at right angles to the fluid flow in the passage, the end of the rod froms the further orifice with the wall of the passage 31.

In use, therefore, when the highest gear is engaged, the hydraulic governor operates as described above. However, when a lower gear ratio is engaged the valve is opened to permit flow through the further orifice from the passage 2 to the passage 3. As a result the pressure diflerence across the piston 13 is less for any given engine speed, and consequently the maximum engine speed for any given setting of the lever is increased. Moreover, since the valve 32 is opened when the electro-magnet is energised, in the event of an electric failure, the maximum engine speed for a given setting of the lever 24 is restricted to the lower value on all gear ratios.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A hydraulic governor for controlling the rate of supply of liquid fuel to a vehicle internal combustion engine of the kind having a multi-ratio gearbox associated therewith, the governor comprising a body part, a fluid pump mounted within said body part and adapted to be driven by the engine, a fluid outlet from the pump, a passage in the body part connected to said outlet, an orifice positioned in said passage and across which a pressure dilference will be developed when fluid passes through the passage, means movable in response to the pressure downstream of said orifice, the position of said means serving to determine the rate of supply of liquid fuel to the engine, a further passage in the body part, said further passage being connnected in parallel with said orifice, a further orifice positioned in said further passage and which when fluid is delivered by the pump modifies the pressure to which the means is subjected, and valve means mounted in said further passage, said valve means being operable to prevent the flow of fluid through said further orifice when a selected ratio of the gearbox is engaged.

2. A hydraulic governor for controlling the rate of supply of liquid fuel to a vehicle internal combustion engine of the kind having a multi-ratio gearbox associated therewith, the governor comprising a body part, a fluid pump mounted within said body part and adapted to be driven by the engine, a fluid outlet from the pump, a passage in the body part connected to said outlet, an orifice positioned in said passage and across which a pressure difference Will be developed when fluid passes through the passage, means movable in response to the pressure downstream of said orifice, the position of said means serving to determine the rate of supply of liquid fuel to the engine, a further passage in the body part, said further passage being connected in parallel with said orifice, a further orifice positioned in said further passage and which when fluid is delivered by the pump modifies the pressure to which the means is subjected, a valve seating in said further passage, a valve closure member for co-operation with said seating, resilient means for urging the valve closure member into contact with the valve seating to prevent the flow of fluid through said further passage, a solenoid mounted within the body part, a solenoid armature connected to the valve closure member and which when the solenoid is energized moves the closure member to permit fluid flow through said further passage, said solenoid being de-energised when a selected ratio of the gearbox is engaged.

References Cited by the Examiner UNITED STATES PATENTS 9/41 Kendrick 91-31 10/59 Nallinger 74472.1

Claims

1. A HYDRAULIC GOVERNOR FOR CONTROLLING THE RATE OF SUPPLY OF LIQUID FUEL TO A VEHICLE INTERNAL COMBUSTION ENGINE OF THE KIND HAVING A MULTI-RATIO GEARBOX ASSOCIATED THEREWITH, THE GOVERNOR COMPRISING A BODY PART, A FLUID PUMP MOUNTED WITHIN SAID BODY PART AND ADAPTED TO BE DRIVEN BY THE ENGINE, A FLUID OUTLET FROM THE PUMP, A PASSAGE IN THE BODY PART CONNECTED TO SAID OUTLET, AN ORIFICE POSITIONED IN SAID PASSAGE AND ACROSS WHICH A PRESSURE DIFFERENCE WILL BE DEVELOPED WHEN FLUID PASSES THROUGH THE PASSAGEWAY, MEANS MOVABLE IN RESPONSE TO THE PRESSURE DOWNSTREA, OF SAID ORIFICE, THE POSITION OF SAID MEANS SERVING TO DETERMINE THE RATE OF SUPPLY OF LIQUID FUEL TO THE ENGINE, A FURTHER PASSAGE IN THE BODY PART, SAID FURTHER PASSAGE BEING CONNECTED IN PARALLEL WITH SAID ORIFICE, A FURTHER ORIFICE POSITIONED IN SAID FURTHER PASSAGE AND WHICH WHEN FLUID IS DELIVERED BY THE PUMP MODIFIES THE PRESSURE TO WHICH THE MEANS IS SUBJECTED, AND VALVE MEANS MOUNTED IN SAID FURTHER PASSAGE, SAID VALVE MEANS BEING OPERABLE TO PREVENT THE FLOW OF FLUID THROUGH SAID FURTHER ORIFICE WHEN A SELECTED RATIO OF THE GEARBOX IS ENGAGED.