GB2187794A

GB2187794A - Device for immolising a vehicle

Info

Publication number: GB2187794A
Application number: GB8705425A
Authority: GB
Inventors: Dennis Harold Norris; David Roberts
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-03-10
Filing date: 1987-03-09
Publication date: 1987-09-16
Also published as: GB8605794D0; GB8705425D0

Abstract

The device comprises a self- latching relay 1 for controlling the supply of power to the engine and is not energised by normal activation of the ignition circuit. The relay is energised by a switch or push button 2 hidden at a convenient location in the vehicle. The relay may serve to control the supply of fuel to the engine or the supply of electricity to one or other of the electrical circuits. Instead of a single push button, a number of push buttons operable in a certain order may be used to energise the relay. Alternatively the relay may only be energised after operating the radio, horn and headlights. The relay may be energised by an ultrasonic, infra red, optical or radio frequency transmitter/receiver system. <IMAGE>

Description

SPECIFICATION Device for immobilising a vehicle This invention relates to automotive vehicles and is particularly concerned with a device for immobilising the automotive engine system of such a vehicle after a period of time.

Laden goods vehicles are not infrequently stolen, often under threat of violence to the legitimate driver. In such a case it may be more politic to allow the vehicle to be driven away rather than to risk injury or even death by resisting a threat of violence. It is an object of the invention to provide a device which will allow a vehicle stolen under such circumstances to be driven away for a limited time or distance only, thereby removing the threat of violence from the legitimate driver and bringing the vehicle to a halt at a point not far from the scene of the theft. Thus when the theft is reported, the police will know approximately where to find the vehicle and will stand a better chance of apprehending the criminals.

According to the present invention there is provided, in an automotive engine system of a motor vehicle having an electrical ignition circuit which can be activated by an ignition key or the like operated by driver, a device for immobilising the system, wherein relay means is proVided for controlling the supply of power to the engine, said relay means being inoperable by normal activation of said ignition circuit, and wherein means is associated with an electrical circuit of the system for operating the relay means.

Conveniently the relay means is associated with the fuel supply and is preferably arranged to control the supply of fuel to the engine, and the arrangement is such that after the ignition has been switched on, the vehicle can be driven only a short distance before no more fuel reaches the engine. The relay can be rendered operative by the operation of at least one hidden switch or push button, known only to the driver, or by operating one or more of the electric circuits of the vehicle either singly or in a predetermined sequence.

Thus the relay can be rendered operative by, for example, operating the horn, direction indicators and/or radio thereby permitting the fuel to be supplied to the engine.

It will be appreciated that while the present device has particular value in relation to laden goods vehicles, it is also applicable to private motor vehicles.

In order to enable the invention to be more readily understood, some examples thereof will now be described in greater detail.

In a first example of the invention, a security delivery van has a normal petrol engine but the electrical system of the van is modified so that operation of the ignition circuit by insertion of the iginition key does not, as is normal, activate the petrol pump. Instead a relay is incorporated in the ignition circuit for connecting the petrol pump in circuit once the relay has been triggered. The relay is one which, when it has been triggered, has a selflatching capability and can keep the petrol pump energised in the circuit for as long as the ignition switch is engaged.

Separate means is provided for triggering the relay and may be in the form of a push button installed at a secret location in the vehicle.

In the operation of this example, if the vehicle is stolen or driven off by an unauthorised person using the vehicle ignition key, then switching on the ignition circuit will not operate the petrol pump and the vehicle will be able to be driven a distance depending upon the amount of petrol present in the carburettor and in the piping between the pump and the carburettor. The vehicle will then stop and appear to have run out of petrol. Since the distance which the vehicle will travel is relatively short, about three quarters of a kilometre, it will be relatively easy to repossess the vehicle and apprehend the unauthorised driver.

An authorised driver, after switching on the ignition, will operate the push button thereby triggering the relay and bringing the petrol pump into operation in the normal manner.

However, this example is not applicable to many current vehicles in which the petrol pumps are operated mechanically and not electrically. Therefore in a second example, a solenoid valve is arranged in the petrol supply line and is arranged normally to close the petrol supply line. The ignition circuit incorporates a self-iatching relay, as in the first example, and the relay is arranged to open the solenoid valve to permit petrol to be supplied to the engine once the relay has been triggered by operation of the push button.

In a third example of the invention, the low voltage circuit of the distributor incorporates a time delay siwtch. The arrangement is such that when the ignition switch is operated, the time delay switch is brought into operation to cut out the distributor voltage after a predetermined period so as to bring the vehicle to a halt. In this example, the relay is arranged to energise the distributor low voltage circuit or isolate the time delay switch. Instead of a time delay switch, a thermal switch, arranged to break connection after a predetermined engine temperature has been reached, could be used.

In the application of the second example of the invention to a diesel engine, it is necessary to provide a fuel reservoir in the fuel supply line downstream of the solenoid valve because interruption of the fuel supply would cause immediate engine failure. The provision of the reservoir allows the engine to run for a predetermined period of time, say 2 or 3 min utes, to give all the necessary delay required by the system.

The present invention is also applicable to vehicles with petrol engines incorporating fuel injection systems. In one modification of the second example for use in petrol injection engines, the solenoid valve is replaced by a two-way solenoid valve which is capable either of drawing fuel from the tank for injection purposes when the relay has been triggered or which merely recirculates the fuel in an injection manifold without drawing fresh fuel from the tank when the relay has not been triggered. Alternatively, the second example may be modified for use in petrol injection engines by the provision of a reservoir as in the application of the second example to a diesel engine.

It will be appreciated that the third example of the invention is applicable to both diesel and petrol injection engines.

In the above examples, the relay has been triggered by operation of a push button. It will be appreciated that the push button is located at a location into the vehicle known only to authorised persons. It is possible to provide more than one push button and to arrange the circuit so that the push buttons have to be operated in a predetermined sequence in order to trigger the relay. Thus, the push buttons could be numbered and assembled in a panel and each vehicle could have a coded number which would have to be pressed on the push buttons in order to trigger the relay.

Instead of operating the relay by means of push buttons, it is possible to trigger the relay by operating any one or more of the other electric circuits of the vehicle. Thus the arrangement of the circuits may be such that the relay is triggered only after a sequence of operations has been performed such as turning on the radio, operating the horn and flashing the headlights, and only in the correct order and each of these operations in turn could be made to operate an appreciated that instructions of varying degrees of complexity can be set up for triggering the relay thus making it more difficult for unauthorised persons who may be aware of this invention to circumvent the invention and trigger the relay.

In order to enable the invention to be more readily understood, reference will now be made to the accompanying drawings, which illustrate diagrammatically and by way of example some embodiments thereof and in which: Figure 1 is the circuit diagram of a selflatching relay; Figures 2 to 5 each show the use of the relay shown in Figure 1 in part of an engine circuit.

Referring now to Figure 1, there is shown a self-latching relay 1 with a push button 2 by depression of which a coil 3 is energised by the electrical supply. Energisation of the coil 3 cause the relay contacts 4 to make. If desired the output side of the relay may be connected through a resistor 5 to a light emitting diode 6 which can provide a signal showing that the push button has been depressed.

Figure 2 shows the relay 1 used to control a solenoid valve 7 in a fuel line 8 leading from the fuel tank to the carburettor of an engine.

Operation of the ignition switch 9 will not cause the solenoid valve 7 to open and permit fuel flow until the press button 2 of the relay has been depressed.

Figure 3 shows an arrangement similar to that shown in Figure 2 but adapted for use with a diesel engine in the manner described above. In this case the fuel line 8 incoporates a flow regulated reservoir 10 downstream of the solenoid valve 7.

Figure 4 shows an arrangement in which the ignition circuit of an engine includes between the ignition switch 9 and the ignition coil (not shown), the parallel connection of the relay 1 and a thermotime switch 11, which is arranged to cut out when the engine temperature reaches a preset value, unless the push button 2 of the relay 1 has been operated.

Figure 5 shows an arrangement similar to Figure 4 for use in a fuel injection system. In this case the parallel connection of the relay 1 and the thermotime switch 11 is connected after a fuel pump relay 12 in the fuel pump operating circuit.

Whiie the self-latching relay 1 shown in Figure 1 has been described as being operable by means of the push-button 2, in a further modification of the invention the self-latching relay is operable by remote control using means operated by ultrasonics, infra-red light or radio waves, preferably 27 MHz radio waves.

Thus, for example, the push button 2 of the self-latching relay 1 is repiaced by a radio receiver which is arranged to establish communication across the relay terminals when an appropriate signal is received. The driver is in possession of a small transmitter which may, for example, be attached to a key ring and which is capable of transmitting the appropriate signal to the receiver to operate the selflatching relay, from inside or from outside the vehicle. Alternatively, the transmitter might be carried by the driver separately from the key ring or could even be mounted somewhere in the vehicle. In any case the receiver will be mounted in the vehicle in an inconspicuous and suitable position.

An advantage of using remote control is that the driver can exercise discretion over the operation of the relay and that in the absence of the transmitter, the relay remains open so that the vehicle only has a limited range over which it can be driven before coming to a halt. A further advantage is that there are no visible or hidden switches and the like that could be discovered by a prospective thief.

Claims

1. In an automotive engine system of a motor vehicle having an electrical ignition circuit which can be activated by an ignition key or the like operated by a driver, a device for immobilising the system, wherein relay means is provided for controlling the supply of power to the engine, said relay means being inoperable by normal activation of said ignition circuit, and wherein means is associated with an electrical circuit of the system for operating the relay means.

2. A device as claimed in Claim 1, wherein the relay means is arranged to control the supply of fuel to the engine and the arrangement is such that, after the ignition circuit has been activated, the vehicle incorporating the system can be driven only a short distance before no more fuel reaches the engine.

3. A device as claimed in Claim 2, in a petrol driven vehicle, wherein the relay means is incorporated in the electrical circuit of an electrically driven petrol pump.

4. A device as claimed in Claim 2, in a petrol driven vehicle incorporating a mechanically operated petrol pump, wherein a solenoid valve is arranged normally to close a petrol supply line of the vehicle, and wherein the relay means is arranged, upon operation, to open said valve to permit petrol to be supplied to the engine.

5. A device as claimed in Claim 2 in a diesel driven vehicle incorporating a mechanically operated diesel pump, wherein a solenoid valve is arranged normally to close a fuel supply line of the vehicle, and wherein the relay means is arranged, upon operation, to open said valve to permit fuel to be supplied to the engine, there being a reservoir in the fuel supply line downstream of the solenoid valve.

6. A device as claimed in Claim 1, wherein the relay means is connected in the low voltage circuit of a distributor of the engine system in parallel with a normally closed switch which is arranged to break connection after a predetermined time delay and/or after a predetermined engine temperature has been reached.

7. A device as claimed in any preceding claim, wherein at least one siwtch or push button is provided for completing the electrical circuit for operating the relay means, closure of the switch or pressing of the push button thereby operating the relay means.

8. A device as claimed in Claim 7, wherein a plurality of switches or push buttons is provided and have to be operated in a predetermined sequence to complete the circuit for operating the relay means.

9. A device as claimed in any one of Claims 1 to 6, wherein the relay means is adapted to be operated by operating one or more of the electric circuits of the vehicle either singly or in a predetermined sequence.

10. A device as claimed in any preceding claim, wherein the relay means is a self-latching relay.

11. A device as claimed in any one of Claims 1 to 6, wherein a receiver is provided for completing the electrical circuit for operating the relay means, and wherein a transmitter is provided for generating a signal to cause the receiver to complete said circuit.

12. A device as claimed in Claim 11, wherein said transmitter and receiver transmit and receive radio waves.

13. In an automotive system of a motor vehicle having an electrical ignition circuit which can be activated by an ignition key or the like operated by a driver, a device for immobolising the system substantially as hereinbefore described in any one of the foregoing examples and/or with reference to Figure 1 and any one of Figures 2 to 5 of the accompanying drawings.