GB1600622A - Fuel pumping apparatus for internal combustion engine - Google Patents

Description

(54) FUEL PUMPING APPARATUS FOR INTERNAL COMBUSTION ENGINES (71) We, LUCAS INDUSTRIES LIMITED, a British Company of Great King Street, Birmingham B19 2XF England, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: This invention relates to a fuel pumping apparatus for supplying fuel to an internal combustion engine and comprising a fuel supply pump operable in use to supply fuel to an internal combustion engine, a governor mechanism operable to control the amount of fuel supplied to the engine by the supply pump, said governor mechanism in use being responsive to the speed of the engine and including a manually operable member movable to determine the operating speed at which the governer means operates to reduce the fuel supply to the engine and stop means acting to limit the movement of the member in the direction to raise said operating speed.

Such apparatus is well known and when fitted to a diesel engine, the supply pump delivers measured quantities of fuel to the combustion spaces of the engine in turn.

When the diesel engine is fitted to a vehicle and drives the vehicle through a transmission including a multi-ratio gearbox, it is desirable to limit the maximum engine speed when the highest ratio of the gearbox is the ratio which gives the lowest engine speed for a given road speed is selected and to allow an increased engine speed when the other ratios of the gearbox are selected.

An example of such an apparatus is shown in the specification of British Patent 1135932 and utilises fluid under pressure to displace a piston forming a stop for the aforesaid member. Also provided is a valve which is connected by a Bowden cable to the vehicle gearbox. The provision of the fluid under pressure to the cylinder containing the piston requires special connections on the apparatus and these are often inconvenient to provide since the stop means is generally at a position removed from the fuel pumping portion of the apparatus.

Moreover, the Bowden cable has to be very carefully located and even so can tend to stick in service.

The object of the invention is to provide such an apparatus in a simple and convenient form.

According to the invention, in a fuel pumping apparatus of the kind specified, said stop means comprises an axially movable plunger, a solenoid for moving said plunger between an operative position and an inoperative position, a stop member engageable by said manually operable member to limit the movement thereof, said stop member being movable by force applied thereto from a first position to a second position and lock means operable when the plunger is in said operative position to retain said stop member in said first position said lock means being released to permit the stop member to move to second position when the plunger is moved to the inoperative position.

According to a further feature of the invention said solenoid when energised, moves said plunger to the inoperative position.

According to a still further feature of the invention resilient means is provided to bias the plunger to the operative position.

One example of a fuel pumping apparatus in accordance with the invention will now be described with reference to the accompanying drawings in which.

Figure 1 is a diagrammatic representation of the pumping apparatus, Figure 2 is an electrical circuit diagram of the apparatus, Figure 3 is a side elevation of the apparatus with parts thereof in section and Figures 4 and 5 show portions of the apparatus in different operating positions.

With reference to Figure 1 of the drawings, the apparatus comprises a fuel supply pump 10 which by way of example, is shown as a multi-plunger "in line" pump. The pump has a plurality of outlets 11 for connection respectively to the fuel injection nozzles of an associated engine. Moreover, the pump 10 is driven in timed relationship with the associated engine.

Associated with the pump 10 is a mechanical governor generally indicated at 12 and which comprises a plurality of governor weight 13 which are driven from the cam shaft of the pump so as to impart a force to an axially movable abutment 14. The abutment 14 is engaged by a govenor spring 15 and is coupled by means of a pivotal link 16 to the control rod 17 of the pump. The other end of the governor spring 1 engages a further abutment 18 which is pivotally connected to one end of a lever 19. The other end of the lever in use, is connected to the throttle control of the vehicle so as the lever 19 constitutes the aforesaid manually operable member.

In use, as the speed of the associated engine increases the weights 13 will move outwardly to compress the governor spring 15. In so doing the control rod 17 of the pump 10 is moved to reduce the amount of fuel supplied to the engine thereby causing a reduction of the engine speed. If the lever 19 is moved in the anti-clockwise direction then the force exerted by the spring 15 will increase and the control rod 17 of the pump will be moved to increase the amount of fuel supplied to the engine.

As shown the lever 19 is engaging a stop 20 and this stop determines the idling speed of the associated engine. The further stop 21 is provided to limit the maximum speed of the engine It will be apPreciated that Figure 1 is diagrammatic and in a practical construction a further spring known as the "idling spring" would be provided effectively in series with the spring 15, but of a lighter construction, to provide the required governor sensitivity for the engine idling condition.

As has been explained it is sometimes necessary to limit the maximum speed of the engine when the highest gear ratio of the gearbox coupling the engine to the transmission of the vehicle is selected. By the highest gear or gear ratio we mean that ratio which gives the lowest engine speed for a given road speed. It is nevertheless desirable to be able to provide more power when a lower gear or gear ratio is selected and to enable this to take place the setting of the stop 21 is automatically adjusted depending on which gear or gear ratio is engaged.

For this purpose and as shown in Figure 2 a solenoid 22 is provided which is connected in a series circuit with a switch 23 associated with the gate of the gearbox control lever 24. When the control lever 24 is moved to the position in which the highest gear ratio is engaged or will be engaged, the switch 23 is opened to de-energise the solenoid 22.

Referring now to Figure 3 there is shown in side elevation the construction of the stop 21 and its mounting on the side of the apparatus incorporating the pump 10 and the governor mechanism 12. The lever 19 is illustrated but in the practical construction, the stops 20 and 21 co-operate with a member 25 which is mounted on the shaft 26 which carries the lever 19, it being appreciated that the part of the lever 19 which is connected to the abutment 18 is within the governor housing.

The member 25 defines two ears 27 and 28, the ear 27 co-operating with the idling stop 20 and the ear 28 with the stop 21.

The two stops 20 and 21 are mounted on a web 29 extending outwardly from the apparatus and the stop 21 comprises a body portion 30 of stepped cylindrical form the narrower portion of which is in screw thread engagement with the web 29. A lock nut 31 is provided to secure the body portion once the setting of the stop has been achieved.

The body portion 30 defines a stepped cylindrical bore in which is located a stop member 32. The stop member 32 extends from the body part 30 for engagement by the ear 28 and an enlarged portion of the stop member is slidable within an intermediate portion of the bore formed in the body part. A further bore is provided in the stop member 32 and extending into this bore is an axially movable plunger 33 which extends from a solenoid housing 34 which is adjustably mounted in the wider portion of the bore in the body part 30. A further lock nut 35 is provided to lock the solenoid housing relative to the body part 30.

The solenoid housing contains a spring which loads the plunger towards the left as seen in Figure 3 and in this position the plunger is said to be in its operative position.

Moreover, the stop member 32 is movable from a first position to a second position and in the position shown in Figure 3, the stop member is in the first position thereby limiting the extent to which the lever 19 can be moved in the direction to increase the speed of the engine.

Formed in the side wall of the wider portion of the stop member are two diametrically disposed openings which receive lock balls 36 and these lock balls can co-operate with depressions 37 formed in the wall of the intermediate portion of the bore in the body part 30. The depressions are more clearly seen in Figure 4. The lock balls are retained in the depressions as seen in Figure 3, by the plunger 33 when the latter is in its inoperative position. The end portion of the plunger is of reduced diameter and when the plunger is in its inoperative position as shown in Figure 4, it permits the lock balls to be urged out of the depressions.

In operation, when the aforesaid highest gear ratio is engaged the solenoid contained in the housing 34 is de-energised and the plunger 33 is moved by its spring to its operative position thereby retaining the lock balls in the depressions and preventing movement of the stop member 32 from its first to its second position. Thus the extent of movement of the lever 19 is limited and a reduced maximum engine speed is obtained.

When the highest gear ratio is not engaged the solenoid within the housing 34 is energised and the plunger 33 is moved to its inoperative position against the action of its spring. The stop member 32 however, is not spring loaded and therefore, remains in its first position until axial pressure is applied to it by the ear 28 as the lever 19 is moved by the operator to increase the engine speed. The stop member is then moved from the position shown in Figure 4 to the position shown in Figure 5 and it will be observed that in Figure 5 the lock balls have been moved out of the depressions 37 by the movement of the stop member.

When the pressure exerted by the ear 28 on the stop member 32 is released and the highest gear ratio re-engaged, the step on the plunger 33 imparts axial movement to the stop member 32 through the intermediary of the lock balls 36 and the parts assume the position shown in Figure 3.

If desired a light spring may be interposed between the plunger and the stop member.

The spring will therefore tend to urge the stop member towards the first position whenever the pressure exerted on the stop member by the ear 28 is removed. When under this condition, the solenoid is deenergised the lock balls will be moved by the plunger 33 into the depressions 37.

It will be appreciated that if there is a failure in the supply of electrical power, the solenoid will be de-energised and the stop member will be moved to its first position and locked in this position once the pressure exerted by the ear 28 has been removed.

WHAT WE CLAIM IS: 1. A fuel pumping apparatus for supplying fuel to an internal combustion engine and comprising a fuel supply pump operable in use to supply fuel to an internal combustion engine, a governor mechanism operable to control the amount of fuel supplied to the engine by the supply pump, said governor mechanism in use being responsive to the speed of the engine and including a manually operable member movable to determine the operating speed at which the governor means operates to reduce the fuel supply to the engine and stop means acting to limit the movement of the member in the direction to raise said operating speed, said stop means comprising an axially movable plunger, a solenoid for moving said plunger between an operative position and an inoperative position, a stop member engageable by said manually operable member to limit the movement thereof, said stop member being movable by force applied thereto from a first position to a second position and lock means operable when the plunger is in said operative position to retain said stop member in said first position said lock means being released to permit the stop member to move to second position when the plunger is moved to the inoperative position.

2. An apparatus according to Claim 1 in which said solenoid when energised, moves said plunger to the inoperative position.

3. An apparatus according to Claim 1 or Claim 2 including resilient means for biasing the plunger to the operative position.

4. An apparatus according to Claim 3 including further resilient means acting intermediate the plunger and the stop member and acting to urge the stop member to the first position from the second position when the plunger is moved to the inoperative position.

5. An apparatus according to Claim 1, 2, 3 or 4 in which said lock means comprises a lock ball.

6. An apparatus according to Claim 1 in which said stop member comprises a stepped member having a bore formed in the wider portion thereof, said bore accommodating said plunger, said stepped member being slidably accommodated within a housing adjustably mounted on a part secured to the body of the apparatus, said lock means comprising a ball located within an aperture extending through the wall of the bore in the stepped member, and a depression formed in said housing to receive said ball, said plunger having a reduced end portion which when the plunger is in said inoperative position permits the ball to be displaced out of said depression upon movement of the stop member to said second position.

7. An apparatus according to Claim 6 in which said solenoid is adjustably mounted on said housing.

8. A fuel pumping apparatus for supplying fuel to an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. operative position thereby retaining the lock balls in the depressions and preventing movement of the stop member 32 from its first to its second position. Thus the extent of movement of the lever 19 is limited and a reduced maximum engine speed is obtained. When the highest gear ratio is not engaged the solenoid within the housing 34 is energised and the plunger 33 is moved to its inoperative position against the action of its spring. The stop member 32 however, is not spring loaded and therefore, remains in its first position until axial pressure is applied to it by the ear 28 as the lever 19 is moved by the operator to increase the engine speed. The stop member is then moved from the position shown in Figure 4 to the position shown in Figure 5 and it will be observed that in Figure 5 the lock balls have been moved out of the depressions 37 by the movement of the stop member. When the pressure exerted by the ear 28 on the stop member 32 is released and the highest gear ratio re-engaged, the step on the plunger 33 imparts axial movement to the stop member 32 through the intermediary of the lock balls 36 and the parts assume the position shown in Figure 3. If desired a light spring may be interposed between the plunger and the stop member. The spring will therefore tend to urge the stop member towards the first position whenever the pressure exerted on the stop member by the ear 28 is removed. When under this condition, the solenoid is deenergised the lock balls will be moved by the plunger 33 into the depressions 37. It will be appreciated that if there is a failure in the supply of electrical power, the solenoid will be de-energised and the stop member will be moved to its first position and locked in this position once the pressure exerted by the ear 28 has been removed. WHAT WE CLAIM IS:

1. A fuel pumping apparatus for supplying fuel to an internal combustion engine and comprising a fuel supply pump operable in use to supply fuel to an internal combustion engine, a governor mechanism operable to control the amount of fuel supplied to the engine by the supply pump, said governor mechanism in use being responsive to the speed of the engine and including a manually operable member movable to determine the operating speed at which the governor means operates to reduce the fuel supply to the engine and stop means acting to limit the movement of the member in the direction to raise said operating speed, said stop means comprising an axially movable plunger, a solenoid for moving said plunger between an operative position and an inoperative position, a stop member engageable by said manually operable member to limit the movement thereof, said stop member being movable by force applied thereto from a first position to a second position and lock means operable when the plunger is in said operative position to retain said stop member in said first position said lock means being released to permit the stop member to move to second position when the plunger is moved to the inoperative position.

2. An apparatus according to Claim 1 in which said solenoid when energised, moves said plunger to the inoperative position.

3. An apparatus according to Claim 1 or Claim 2 including resilient means for biasing the plunger to the operative position.

4. An apparatus according to Claim 3 including further resilient means acting intermediate the plunger and the stop member and acting to urge the stop member to the first position from the second position when the plunger is moved to the inoperative position.

5. An apparatus according to Claim 1, 2, 3 or 4 in which said lock means comprises a lock ball.

6. An apparatus according to Claim 1 in which said stop member comprises a stepped member having a bore formed in the wider portion thereof, said bore accommodating said plunger, said stepped member being slidably accommodated within a housing adjustably mounted on a part secured to the body of the apparatus, said lock means comprising a ball located within an aperture extending through the wall of the bore in the stepped member, and a depression formed in said housing to receive said ball, said plunger having a reduced end portion which when the plunger is in said inoperative position permits the ball to be displaced out of said depression upon movement of the stop member to said second position.

7. An apparatus according to Claim 6 in which said solenoid is adjustably mounted on said housing.

8. A fuel pumping apparatus for supplying fuel to an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to and as shown in the accompanying drawings.