GB2273129A - Anti-theft i.c.engine fuel valve control system - Google Patents

Abstract

A solenoid operated valve 1 biassed to a closed position in which it will cut off the supply of fuel to the engine will be opened when a circuit 2 is completed. For the solenoid 6 to be energised a switch 5 and a switch 3 in circuit 2 must be closed. Switch 3 is lock-operated and may be in a concealed position in the vehicle driven by the engine. The switch 5 may be the ignition switch or a light or radio operated switch. The lockable switch 3 may be operated by a key 15 or an electric signal. <IMAGE>

Description

SECURITY DEVICE This invention relates to an anti-theft device for use in connection with an internal combustion engine.

In recent years the incidence of automobile theft has increased to the extent that insurance premiums often reflect the presence or absence in a vehicle of a car anti-theft device. Such devices are ordinarily in the form of an alarm which is locked on once the vehicle is parked and actuated by sensing devices for example infrared sensors or tilt switches. It is also known to use security devices which disable the electrical system of the vehicle or mechanically disable the steering wheel and/or footpedals.In all of these forms deactivation of the device is effected by key means for example ccewentional natal keys, keypads, radio operated key locks, electronic keys and infrared keys.

A disadvantage of such devices is that it is appreciated readily by a would be thief that a security device is fitted deterring only the faint hearted and being of little hindrance to others. In practice, the aoccmplished thief or joyrides will readily disarm the most sophisticated of anti-theft devices.

It is an object of the invention to provide a generally simple antitheft device which may be adapted to be fitted in a number of ways so that even its presence will not alert a would be thief to the exact mode of installation.

In accordance with the present invention there is provided an antitheft device for use in connection with an internal combustion engine, the device comprising electrically operated valve means, first electric circuit means adapted to include said valve means, the valve being adapted to be included in the fuel supply line of the engine to control the same, and primary and secondary switch neans adapted to be included in said first circuit in use, the first circuit requiring closure of beth said switch means for the valve means to be actuated, the primary switch means being adapted to be included in a second electrical circuit associated with the internal combustion engine or a vehicle in which said engine is grunted, said second circuit including a source of electricity and a control switch, the primary switch meeans being adapt to be actuated simultaneously with said control switch and said secondary switch means being lock-corrtrofled independently of said primary switch means.

In a preferred embodiment the valve is biassed to a closed position in which it will restrict the supply of fuel to the engine and comprises a solenoid which, when included in said first circuit, will open the valve when said first circuit is completed by closure of both said primary and secondary switch means.

A tine delay circuit may be associated with or incorporated in said first circuit meQns by-passing said secondary switch for a given period or isolating said secondary switch after said given period.

Said second electrical circuit may be an auxiliary circuit of said engine and said control switch operable simultaneeusly with the primary switch may be the ignition control switch of the engine. In this arrangnment said second electrical circuit may be the ignition circuit of a petrol engine and said control switch may be the ignition switch.

The secondary switch may be lockable in the circuit-open position by a key-controlled lock. Alternatively the secondary switch may be lockable in the circuit-open position by an electronic, radio or infra-red code-controlled lock.

The said valve means may be controlled by a solenoid mounted in a housing associated with the carburettor or fuel injection system of the internal comnbustion engine, the valve means being spring-biassed to a position normally closing the fuel supply to said carburettor or fuel injection system and said solenoid being adapted, when energsed, to mLve the valve means to an open position allowing the supply of fuel to the carburettor or fuel injection system.

A preferred enExYinEnt of the invention will now be described by way of non-limitative example with reference to the accompanying drawing which illustrates schetnatically an actatbile anti-theft device in accordance with the invention.

The anti-theft device shown comprises an electrically operated fuel valve 1 associated with a first electric circuit generally denoted 2 which is connectable through a switch 3 to a second, electric supply circuit generally denoted 4, and a control switch 5 which completes said supply circuit 4 and is an existing part of a vehicle electrical system.

The valve 1 comprises a solenoid 6 which in known fashion operates a gate valve housed in valve body 7. The body 1 has inlet and outlet bores 8 (one of which is shown) to which a fuel line of the vehicle can be plumbed.

Nhen installed, the valve 1 operates as a fuel shut-off valve and is biased toward the closed position. Suitably the valve 1 is located in the bulkhead of the vehicle close to an injection or carburation system of the autornobile engine so that should the engine be started when the valve is closed it will be starved of fuel and stall.

The coil of solenoid 6 is connected in series to earth by lead 9 and to the circuit 2. This circuit 2 comprises a fused lead 10 connecting the switch 3 through fuse 11 to the solenoid 6. A monitor device 12 connected between lead 10 and earth by wires 13 contains an lED 14 and is operable to detect current in lead 10. It will be appreciated that the presence of current in lead 10 energises solenoid 6 thereby pening valve 1 and permitting fuel to flow to the engine.

Switch 3 is actuated by a security key 15 to connect fused lead 10 to supply lead 16 of the electrical supply circuit 4. The supply lead 16 is connected conveniently to an auxiliary supply outlet 17 of the switch 5 which is in this example the ignition switch of the vehicle.

It will be appreciated that solenoid 6 will only be energised when both switch 5 and switch 3 are closed and that this state can be detected by operating the monitor 12. Thus, although it may be possible to start the vehicle by operating the ignition switch (switch 5) or by 'hot wiring' the ignition and starter systems, the engine will be starved of fuel unless switch 3 is also closed. In practice the quantity of fuel found in a carburettor float chamber might carry a car 40 meters before the engine stalls. Advantageously, this my fool a thief into believing that he has suecessfully disabled any security device and the unexpected stalling of the engine might then persuade him to abandon the vehicle.

The invention is not limited to the aforedescribed arrangement of using the preexisting ignition switch as control switch 5. Any other switch or switch means may be utilised so long as it enables the solenoid 6 to be energised when switch 3 is also closed. As an example a light or radio on/off switch could be used. Also, the monitor 12 may be fitted disguised as an auxiliary switch for example for fog lamp.

The device apart from preexisting switch 5 is supplied to the austorner as a kit of parts comprising valve 1, switch 3, monitor 14 and associated wiring with the arrangement and function being as described. The kit my conveniently be assembled and fitted to the vehicle in accordance with written instructions suitable for the cOmpetent DIY person or vehicle mechanic. It is anticipated, for example, that the switch 3 be located in a glove caEartrnrrt or other concealed portion of the vehicle interior so that its presence is not readily apparent to any prospective thief.

It is suggested that a time delay circuit form a part of either the electric circuit 2 or supply circuit 3. Such an arrangerrBnt may for example require that switch 3 nust be operated within a certain tinne of switch 5 otherwise the switch 3 would be isolated and solenoid 6 will not be energised. In the alternative a tinge delay device could be connected across the terminals of switch 3 effectively bypassing this switch for a given period. This would result in the thief being unaware of the presence of the anti-theft device until the period was over and hopefully this would cause him to abandon the vehicle when the engine subsequently stalled.

Although the switch 3 incorporates a security key lock, it may be replaced by any suitable key-switch means for example a key pad, radio operated key lock or electronic key operated lock.

Claims (9)

CLAIMS:

1. An anti-theft device for use in connection with an internal combustion engine, the device comprising electrically operated valve nEans, first electric circuit nEans adapted to include said valve means, the valve being adapted to be included in the fuel supply line of the engine to control the sate, and primary and secondary switch means adapted to be included in said first circuit in use, the first circuit requiring closure of both said switch means for the valve means to be actuated, the primary switch moans being adapted to be included in a second electrical circuit associated with the internal carSxlstion engine or a vehicle in which said engine is mounted, said second circuit including a source of electricity and a control switch, the primary switch means being adapted to be actuated simrltanecusly with said control switch and said secondary switch means being lock-controiled independently of said primary switch means.

2. A device as claimed in clam 1, wherein the valve is biassed to-a closed position in which it will restrict the supply of fuel to the engine and comprises a solenoid which, when included in said first circuit, will open the valve when said first circuit is completed by closure of both said primary and secondary switch neans.

3. A device as claimed in either preceding claim, wherein a tine delay circuit is associated with or incorporated in said circuit neans by-passing said secondary switch for a given period or isolating said secondary switch after said given period.

4. A device as claimed in any one of the preceding claims, therein said second electrical circuit is an auxiliary circuit of said engine and said control switch operable simultaneously with the primary switch is the ignition switch control of the engine.

5. A device as claimed in claim 4, wherein said second electrical circuit is the ignition circuit of a petrol engine and said control switch is the ignition switch.

6. A device as claimed in any one of the preceding claims, wherein the secondary switch is lockable in the circuit-open position by a kay controlled lock.

7. A device as claimed in any one of claim 1-5, wherein the secondary switch is lockable in the circuit-open position by an electronic, radio or infra-red code-controlled lock.

8. A device as claimed in any one of the preceding claims, wherein the said valve means is controlled by a solenoid mounted in a housing associated with the carburettor or fuel injection system of the internal ocubustion engine, the valve means being spring-biassed to a position normally closing the fuel supply to said carburettor or fuel injection system and said solenoid being adapted, when energised, to mnre the valve means to an open position allowing the supply of fuel to the carburettor or fuel injection system.

9. An anti-theft device for use in connection with an internal combustion engine substantially as hereinbefcre described with reference to and as shown in the accompanying schematic drawing.