GB2067244A - Vehicle speed governor of a fuel injection pump - Google Patents

Abstract

The fuel injection pump lever 37 operable from the pedal 46 via the linkage 39...45 is movable to a fuel flow reducing position by a piston rod 35 at a predetermined vehicle speed. The piston 33 is subject to compressed air from a conduit 25 or atmospheric pressure from an inlet 19 by a valve 15 operated in response to a speed detector 1, 2 via a relay 4 and a solenoid 14. <IMAGE>

Description

SPECIFICATION Device for limiting the speed of an automobile vehicle, particularly a lorry The present invention relates to a device for limiting the speed of an automobile vehicle, particularly a lorry.

Utility vehicles, particularly lorries, comprise an engine of the Diesel type which is supplied by an injection pump of which the control lever is connected by a linkage to a control member, particularly the accelerator pedal, actuated by the driver.

Furthermore, different means are known for limiting the speed of a vehicle, but they do not always limit the actual speed of displacement of the vehicle, whatever the gear ratio of the gear box.

The purpose of the device according to the invention is to respond to this criterion. According to the present invention, it comprises a speed check device presenting a predetermined speed threshold for which a pulse is sent to a relay ensuring the control of an electrovalve adapted selectively to connect a cylinder to a source of compressed air and to atmosphere through a calibrated hole, in which cylinder a piston moves against the action of an elastic member, said piston comprising a rod capable of coming into contact, to control the stroke thereof, with the lever of the injection pump, connected by an elastic means to the linkage of the control member actuated by the driver.

As the speed limitation information is emitted directly by the speed check device the actual speed of the vehicle is limited whatever the gear ratio of the gear box.

Furthermore, the device takes into account only the actual speed as a function of the torque of the axle of a vehicle (long torque) and of the chosen speed limit threshold, and several gear box ratios may be concerned by this limitation; in this case, the device also acts as a fuel saver.

For example, with a torque giving a theoretical speed of 11 5 km/hr,a limitation to 80 km/hr and a gear box with 1 3 gears, the following may be obtained: 80 km/hr in 7th high gear at 3000 r.p.m.

80 km/hr in 8th low gear at 2500 r.p.m.

80 km/hr in 8th high gear at 2000 r.p.m.

It may thus be ascertained that, for the same speed of displacement of the vehicle, the engine has a lower rotation speed of 1000 r.p.m. and fuel is consequently saved.

The device is inviolable, during travel, by the driver making a greater effort on the accelerator pedal.

In fact, where the action of the accelerator lever on the lever of the injection pump is limited by the action of the speed limitation control piston, the intermediate elastic means is compressed and the lever of the injection pump remains in its speed limitation position, as the accelerator pedal which is opposite the rod of the piston can only compress the elastic member without acting on the control lever of the pump.

According to another feature, the device may be adapted to all cases, due to its small volume.

The device does not necessitate any modification of the accelerator linkage, as the control piston acts directly on the control lever of the injection pump and this enables all the initial characteristics of the vehicle to be conserved.

Furthermore, if the linkage is developed, the precision of the speed limiter device would be conserved, the latter being independent of the control of the acceleration pedal.

The device according to the invention is simple, this resulting in considerabie reliability. Versatility of functioning is obtained by means of jets which do not require adjustment, the only adjustment being made on the thrust rod of the control piston, which makes it possible to limit more or less the number of revolutions of the engine as a function of the speed limit which has been chosen.

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Fig. 1 is a schematic view of the speed limiter device according to the invention.

Fig. 2 is a variant embodiment of the speed limiter device shown in Fig. 1.

Referring now to the drawings, Fig. 1 shows an embodiment of the speed limiter device according to the invention, which comprises a speed check device 1 which is normally mounted on the vehicle to check its rolling speed, said speed check device comprising a contact member whereby a pilot light is lit up when a chosen speed limit threshold has been reached. A plug 2 is connected, on the one hand, to the electric circuit of this contact member of the speed check device and, on the other hand, to the coil of an electromagnet 3 of a relay 4 via a lead 5. The coil of the relay 4 is thus supplied from the terminals B and C which are respectively connected to the plug 2 via lead 5 and to earth 6 via lead 7.The relay 4 comprises a contact member 8 actuated by the rod 9 of the electromagnet and adapted to come into contact with the contact studs 10, 11, of which one, 10, is connected by a lead 1 2 to one of the terminals 1 3a of a coil 13 of an electromagnet 14 of an electrovalve 1 5 and of which the other contact stud 11 is connected to a terminal E which is not connected to any circuit. Furthermore, the contact member 8 is connected by a lead 16 to an electric current supply terminal 1 7, whilst the terminal 1 3b of the coil 13 of the electrovalve is connected to earth 6.

The electrovalve 1 5 comprises a first chamber 1 8 which is connected to atmosphere via a conduit 1 9 with calibrated orifice, a second chamber 20 which is connected by a conduit 21 and a jet 22 with calibrated orifice to a control cylinder 23, and a third chamber 24 which is connected by a conduit 25 to a source of compressed air. The chambers 20 and 24 communicate with one another by an orifice 26 whose opening may be closed by a valve 27 maintained in ciosed position by a spring 28 in abutment against the bottom of the chamber 24.

A rod 29 actuated by the electromagnet 14 is mounted to slide in bores 30 and 31 of the partitions defining the chambers 18 and 20, said rod 29 presenting an axial conduit 32 opening, on one side, at one of its ends and, on the other side, through a lateral hole 32a into the chamber 18.

When it slides, the rod 29 is capable of passing through the orifice 26 and of coming into contact with the valve 27 in order to bring the latter into open position.

The control cylinder 23 presents, near one of its ends which is connected by conduit 21 to the electrovalve 15, a shoulder 23a against which a piston 33 is in abutment, under the action of a spring 34 in abutment against the end of the cylinder. The piston 33 is provided with a rod 35 which is mounted to slide in a bore 36 of the cylinder 23 and of which the end 35a is capable of coming into contact with a lever 37 mounted to pivot about a pin 38, said lever controlling the injection pump of the engine (not shown in the drawing).

At the end of the lever 37 is pivotally mounted at 40 a rod 39 which is fast with a cylinder 41 in which a piston 42 is slidably mounted against the action of a spring 43 in abutment against the end of the cylinder 41, said piston 42 being fast with a rod 44 forming part of the linkage 45 connected to the accelerator pedal 46 actuated by the driver.

The stroke of the elastic control is at least equal to the displacement of the accelerator lever.

The speed limiter device functions as follows: As soon as the vehicle reaches the chosen speed limit threshold, the pilot light of the speed check device lights up, allowing the electrical supply of the coil of the electromagnet 3 of the relay 4 by the plug 2 and the leads 5 and 7. The relay 4 being energised, the contact member 8 actuated by the rod 9 of the electromagnet 3 comes into contact with the contact stud 10 and ensures supply of the coil 1 3 by the lead 12 and the terminal 1 3b connected to earth 6.

The electromagnet 14 being energised, it acts on the rod 29 which moves in the direction of arrow F and comes into contact by its end with the valve 27 thus ensuring closure of the conduit 32, then, on continuing its stroke, the rod 29 detaches the valve 27 from its seat which allows the opening of the orifice 26 and the passage of the compressed air coming from the conduit 25 of chamber 20 into chamber 20. The compressed air escapes from chamber 20 through conduit 21 and the jet 22 towards the cylinder 23 where it pushes the piston 33 against the spring 34.The rod 35 of the piston is pushed out of the cylinder 23 and comes into contact with the lever 37 of the injection pump when said lever is in particular in the position 37a of maximum running speed of the engine, so that, under the action of the rod 35, the lever 37 is pushed into the position 37b shown in broken lines, and which corresponds to the position of limited running speed of the engine.

The purpose of the jet 22 is to enable the rod 35 to emerge less suddenly, but without being detrimental to the cut-off response time.

As soon as the vehicle slows down, the pilot light of the speed check device is extinguished and the supply of the relay 4 is no longer maintained, with the result that there is no more energisation of the electromagnet, so that the contact member 8 is returned into its initial position where it is in contact with the contact stud 11 which is connected to the terminal E with no supply.

Consequently, the coil 13 of the electrovalve is no longer supplied and the rod 29 moves in the direction opposite to that of arrow F, to occupy the initial position shown in Fig. 1. This results in closure of the valve 27 which closes the orifice 26 and opening of the conduit 32 which places chamber 20 in communication with chamber 1 8.

At that moment, the cylinder 23 is no longer supplied with compressed air and the air located in the circuit between the electrovalve and the piston may be evacuated via orifice 1 9 to atmosphere, which is calibrated to slow down the return of the piston 33, but without being detrimental to the pickup response time of the vehicle.

As soon as the pilot light lights up again, the cycle of functioning of the speed limiter device recommences. To avoid users dismantling the electric system to drive without speed limitation, it is possible to modify the functioning of the piston which involves a variant embodiment, which has been shown in Fig. 2.

In this case, the piston 33 controlling the lever 37 is subjected to the action of compressed air when the device is in rest position and the rod 35 is in retracted position, as shown in Fig. 2. The spring 34 is then in compressed position, so that it acts on the piston 23 only in the active speed limitation phase. Consequently, the coil 13 of the electrovalve 1 5 is connected to terminal E instead of terminal D so that said coil is permanently supplied with electric current from the lead 12.

The permanent energisation of the electromagnet 14 causes the rod 29 to move in the direction of arrow F, thus ensuring that the valve 27 is maintained in open position, in order permanently to supply the cylinder 23 with compressed air via the chambers 24, 20 and the conduit 21. This supply of the coil 13 ceases as soon as the pilot light of the speed check device 1 lights up and ensures energisation of the electromagnet 3 of the relay 4. At that moment, the contact member 8 comes into contact with the contact stud 10 and the supply of the coil 13 is cut off, de-energising the electromagnet 14 and causing the rod 29 to rise. When the rod 29 rises, the valve 27 obturates the orifice 26 and cuts off the supply of cylinder 23. Via the conduit 32 of the rod 29, the air contained in the cylinder 23 escapes through the calibrated orifice 19 towards the atmosphere and the spring 34 pushes the piston 33 as well as the rod 35 which acts on the lever 37 to limit the speed of the vehicle.

The description is, of course, not limiting and the man skilled in the art may make modifications thereto without departing from the scope of the invention.

Claims (6)

1. A device for limiting the speed of an automobile vehicle, and particularly a lorry, of which the engine is supplied by an injection pump comprising a control level which is connected by a linkage to a control member actuated by the driver, wherein said device comprises a speed check device presenting a predetermineu speed threshold for which a pulse is sent to a relay ensuring control of an electrovalve adapted to selectively connect a cylinder to a source of compressed air and to atmosphere via a calibrated hole, in which cylinder a piston moves against the action of an elastic member, said piston comprising a rod adapted to come into contact, in order to control the stroke thereof, with the lever of the injection pump, connected by an elastic means to the linkage of the control member actuated by the driver.

2. A device as claimed in Claim 1, wherein the electrovalve comprises a body presenting a first chamber connected to atmosphere by a conduit of calibrated orifice, a second chamber connected to the control cylinder of the injection pump lever and a third chamber connected to a source of compressed air, the second and third chambers being connected by an orifice whose opening is controlled by a valve disposed in the third chamber, said valve being actuated by a rod passing through the first and the second chamber and which is controlled by an electromagnet, said rod presenting a conduit open at its end and adapted to connect the first and the second chamber.

3. A device as claimed in Claim 1, wherein the control cylinder of the lever actuating the injection pump present at its end which is connected to the second chamber of the electrovalve a stop against which the piston is in abutment, under the action of a spring, of which piston the rod is adapted to come into contact with the control lever of the injection pump when the piston is subjected to the action of the compressed air.

4. A device as claimed in Claim 1, wherein the control cylinder of the lever actuating the injection pump is permanently supplied by the source of compressed air, so that the piston maintains the spring in position of compression and the rod of the piston is capable of acting on the lever under the action of the spring, when the pressure of the compressed air is reduced or eliminated.

5. A device as claimed in Claim 1, wherein the elastic connection means between the linkage and the control lever of the injection pump is disposed in a cylinder in which a piston moves against the action of a spring disposed between the end of the cylinder and one of the faces of the piston.

6. A device for limiting the speed of a vehicle, substantially as described hereinabove and illustrated in the accompanying drawings.