GB2432445A

GB2432445A - Vehicle engine immobiliser control

Info

Publication number: GB2432445A
Application number: GB0523594A
Authority: GB
Inventors: David Neil Cunliffe
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-19
Filing date: 2005-11-19
Publication date: 2007-05-23
Also published as: GB0523594D0

Abstract

An immobiliser for a vehicle engine includes a fuel valve (17) having an electrical actuator requiring a pre-defined data signal to effect operation of the valve (17). An electronic module has a radio frequency receiver having an aerial (12) which controls the supply of the data signal to the valve (17). A portable token (13) has a radio frequency transmitter which transmits a signal for detection by the receiver. The state of the fuel valve (17) is thus controlled by the electronic module dependent upon reception of the transmitted signal. Operation of the system may be inhibited when the speed of the vehicle is above a pre-set minimum and the position of the accelerator pedal may also be monitored to enable the system to be activated only if an attempt is made to drive the vehicle. Engine starter and engine management system inhibition may also be controlled.

Description

VEHICLE ENGINE CONTROL APPARATUS AND METHOD

This invention relates to control apparatus for a vehicle engine and also to a method of controlling the operation of a vehicle engine. In particular, the invention is concerned with the immobilisatjon of a vehicle having an engine fitted with the control apparatus. The invention further relates to a vehicle fitted with such control apparatus.

Crime involving vehicles is increasing in most areas of the world. In the United Kingdom, in 2000 there were over 333,000 actual thefts of complete vehicles including cars, motorcycles and light commercial vans. Each year, 8 out of every 1,000 HGVs in the UK are stolen and of those, only 1 in 1,000 is recovered. This means that each year, over 3,000 HGVs are stolen and never recovered.

There are many proposals for immobilisatjon systems for vehicles, which systems attempt to address the crime statistics mentioned above. Though many of these are effective if operated properly, too often there is a failure by the vehicle driver to use the system in the most appropriate manner, and so the vehicle may be vulnerable to theft notwithstanding the fitting of an immobiliser thereto.

A known form of immobiliser includes an electrically-operated fuel valve which, when closed, prevents the flow of fuel to the engine and thus effectively immobilises the vehicle. Such a valve may be controlled by a key switch but this relies on the vehicle driver removing the key from the switch, so ensuring the valve is closed, when the driver leaves the vehicle. If the driver fails to remove the key, the immobiliser offers no protection whatsoever.

It is a principal aim of the present invention to improve the protection provided by an immobiliser including an electrically-operated fuel valve, without compromising safety of operation of the vehicle.

According to one aspect of this invention, there is provided engine control apparatus for a vehicle engine, comprising an engine fuel valve including an electrical actuator requiring a pre-defined data signal to effect operation of the valve, an electronic module including a radio frequency receiver and arranged to control the supply of said data signal to the fuel valve, and a portable token having a radio frequency transmitter arranged to transmit a token signal for detection by the receiver of the electronic module, whereby the state of the fuel valve may be controlled by the electronic module dependent upon reception of the token signal.

According to a second but closely related aspect of this invention, there is provided a method of controlling the operation of a vehicle engine provided with an engine fuel valve including an electrical actuator requiring a pie-defined data signal to effect operation of the valve, an electronic module including a radio frequency receiver and arranged to control the supply of said data signal to the fuel valve, and a portable token having a radio frequency transmitter arranged to transmit a token signal for detection by the receiver of the electronic module, in which method the fuel valve is set to a closed state in the event that the electronic module fails to detect the token signal transmitted by the token transmitter.

It will be appreciated that the control apparatus and method of this invention serves as an immobiliser for a vehicle. The operation of a vehicle engine fitted with the control apparatus will be prevented by the closing of a valve in the fuel supply line to the engine, in the event that a token is not present in the immediate vicinity (and typically only a few metres) of the vehicle.

Such a token may be carried by the driver of a vehicle, for example in a pocket or suspended from a neck lanyard. Preferably, the token is not associated with the ignition and steering lock keys of the vehicle, so that the driver may leave the keys in the ignition switch or steering lock, perhaps with the engine running and yet the immobiliser may operate in the event an attempt is made to drive away the vehicle.

The fuel valve will have an open state and a closed state, the electrical actuator being arranged to operate the valve to its open state or to maintain the valve in that state only so long as the actuator receives a corresponding data signal from the electronic module. The valve may be spring-loaded to its closed state, and be moved to its open state by a solenoid against the action of the spring loading, the solenoid being energised only when the digital signal is present. In this way, security is enhanced as the solenoid cannot be energised by tampering with the wiring to the electrical actuator. Further, the digital signal for any particular immobiliser installation may be unique to that installation, so that even by determining a code from one installation, it will not be possible to override the electrical actuator of another installation.

In order to ensure the security of the system, the solenoid together with its electrical controller should be fully integrated within the fuel valve. Thus, the electrical controller and terminals to the solenoid may be embedded within a potting compound within a chamber formed in the fuel valve body or housing, to prevent access thereto. In this way, the fuel valve may have a simple three-wire input, for power, common return and digital signal input.

The electronic module may include a speed input for a vehicle speed-related signal, for example derived from an electronic speedometer circuit of the vehicle, a wheel rotation sensor, or from an engine management system.

In this way, for safety reasons closing of the fuel valve may be inhibited in the event that the signal from the portable token is lost, should the vehicle be travelling at more than a pre-set minimum speed. Then, when the speed of the vehicle has fallen to below that minimum speed, or perhaps to zero, the fuel valve may be closed so as then to immobilise the vehicle.

As mentioned, the portable token has a radio frequency transmitter and one possibility is for the token to transmit an encoded signal at regular intervals.

However, as the token must include a power source, such as a battery which may be rechargeable, in order to conserve power it is preferred for the token to include a receiver and to transmit a coded signal only when a request for a coded signal is received. Thus, the electronic module may also include a transmitter as well as its receiver, whereby the electronic module may transmit a suitable signal to the token (if present), requesting the token to transmit its coded signal back to the electronic module. In this way, the number of transmissions required from the token may be greatly reduced and in effect only to when the operation of the vehicle changes in some way and which requires the electronic module to be assured that the correct token is present in the immediate vicinity of the vehicle.

Preferably, the token is arranged so that each time a signal is transmitted thereby, the coding of that signal is changed. The actual code of the signal should follow a sequence pre-loaded into the token and also into the electronic module, and that sequence of codes should differ for each immobiliser installation of this invention, such that each token is specifically associated with an electronic module. In this way, a token for one installation cannot be used with a token for another installation, even though both may use the same type of coding for the transmitted signals and transmit at the same frequency.

A sensor for accelerator pedal position may also be provided, which sensor provides an electrical signal to the control module. In this way, it becomes possible for a driver carrying the token to move away from the vehicle while leaving the engine running, such as may occur for a house-to-house delivery van or truck. The immobiliser may be arranged to allow continued operation of the engine once started even should the token move out of range of the electronic module, so long as no attempt is made to move the vehicle.

Should an unauthorised person attempt to drive the vehicle while the token is out of range, that person will depress the accelerator pedal and this may be detected by the electronic module, which then causes the fuel valve to close by removing the coded signal therefrom.

The electronic module may be connected to the starter circuit for the vehicle, to inhibit operation thereof in the event that the token is not in the immediate vicinity of the vehicle. Further, for a vehicle having an engine management system, the electronic module may also be connected thereto to inhibit the starting thereof unless the token is in the immediate vicinity of the vehicle.

This invention extends to a vehicle whenever fitted with control apparatus for the vehicle engine as described above.

By way of example only, one specific embodiment of engine control apparatus and of an immobiliser method both of this invention will now be described in detail, reference being made to the accompanying drawings in which:-Figure 1 is a block diagram showing the embodiment of control apparatus of this invention; Figure 2 diagrammatically represents a fuel control valve as used in the embodiment of control apparatus; Figure 3 is a flow chart showing the operation of the embodiment; and Figure 4 is a truth table showing the different operational states of the embodiment of immobiliser.

Referring initially to Figure 1, there is shown in block diagram form the embodiment of immobiliser control apparatus for a vehicle engine (not shown).

The apparatus includes an electronic control unit ECU having a microprocessor running a program loaded into memory and which automatically starts when power is supplied to the ECU, typically from a battery 10 along power line 11.

That power line may be fitted with a fuse and be switched by the vehicle ignition switch, in a conventional manner.

The ECU includes a radio frequency transmitter/receiver tuned (in this embodiment, for the UK) to the licence-free frequency of 433 MHz, the transmitter/receiver having an aerial 12 for signals on that frequency. A portable token 13 forming a part of the immobiliser is in the form of a small low-powered radio frequency transmitter/receiver arranged both to receive and interrogation signal and to transmit a coded digital signal on 433 MHz, for reception by the ECU. The program running within the ECU periodically, but dependent upon the operation of the system, transmits a request for a coded digital signal from the token and then analyses any received signal on the 433 MHz frequency and the subsequent operation of the program depends upon whether a signal having a predetermined code is received.

If the ECU recognises the coded signal from the token 13 following the transmission of an interrogation request, the ECU can take whatever is the appropriate action; in the event that no coded signal from the token 13 is received following an interrogation request, which will occur when the token 13 is moved out of range of the ECU, a different action may be taken by the ECU as compared to when the token 13 is in range.

The coded digital signal transmitted by the token 13 when requested preferably is changed on a rolling basis, following a pre-set sequence. By having the pre-set sequence loaded into both the token and also the ECU, the program running in the ECU is able to recognise whether or not a coded digital sequence originates from the token 13 associated with that ECU. Initial synchronisation is performed when a token is first brought into range and the ECU is turned on; the ECU issues an interrogation request and after receiving a coded signal in response from the token, the ECU will issue a second interrogation request. If the received signal corresponds to the anticipated signal, synchronisation will be completed and no further interrogation request issued until the operating parameters of the vehicle are changed necessitating confirmation that the change is authorised and so that the token is still present.

In this way, power consumption by the token may be minimised.

The token 13 comprises a small housing containing the transmitter! receiver and a battery for driving those components. The housing is waterproof and the components are mounted therein in such a way as to isolate those components from shock, for example should the housing be dropped on to a hard surface. Typically, the housing may take the form of a key fob (but should not be connected to the vehicle ignition or steering lock key), or may have a mounting for a lanyard so that it may be hung around the neck. The range of the transmitter within which its transmitted digital signal may effectively be received by the ECU, is only a few metres and typically less than 10 m.

The immobiliser accepts inputs to the ECU from a vehicle speed sensor 14, typically coupled to an electronic speedometer of the vehicle or to an engine management system (EMS) 21 of the vehicle engine. Further, an accelerator pedal position sensor 16 provides a signal to the ECU, but again that sensor may form a part of the EMS.

The ECU controls the operation of an engine fuel valve 17 fitted into a fuel line for the engine, leading to the fuel injection system of the engine, or in the case of a carburetted petrol engine, to the carburettor. Thus, on closing the fuel valve, operation of the engine is inhibited.

The engine fuel valve 17 is spring-loaded to its closed setting, but includes a solenoid for opening the valve against the spring loading. Integrated with that valve 17 is an electrical controller 18 (Figure 2) for the solenoid, that controller having a three-wire input -one for supply positive, one for supply negative (which typically will be connected to the vehicle common return), and one for a coded signal input. The solenoid will be energised to open the valve only when an appropriate digital signal is supplied to the signal input. If that digital signal is not present, the controller will not energise the solenoid and so the valve will be closed, or will remain closed.

Both the ECU and the controller of the valve 17 may be pre-set to require a particular coded digital signal in order to operate the solenoid. The coded signal may differ for each installation of immobiliser, so that knowledge of the appropriate digital signal for one installation will not allow unauthorised operation of the valve 17 of another installation. Further, merely tampering with the wiring to the valve 17 will not allow the solenoid to be energised, so enhancing security of the immobiliser. To this end, the connections to the solenoid and to an electronic circuit for receiving the coded digital signal and switching the supply to the solenoid connections are advantageously all within a chamber formed in the valve body or housing and are embedded in a potting compound.

The ECU drives a warning light 19, which may be mounted in an easily visible position for the driver such as on the dashboard, in order to warn the driver of the state of operation of the immobiliser. The ECU is also connected to the vehicle starter solenoid circuit 20, SO as to inhibit operation of the starter solenoid in the event that the signal from the token 13 is not detected. Further, the ECU may be connected to the EMS 21, to instruct the EMS not to permit operation of the engine in the event that the signal from the token 13 is not detected. In this way, the ECU may control the operation of three separate vehicle systems (fuel supply, starter circuit and EMS), whereby even should an unauthorised person succeed in overriding one of the systems, the vehicle still may not be started.

Despite the above, for safety reasons the ECU utilises the signal from the vehicle speed sensor 14. In the event that the signal from the token 13 is lost when the vehicle is travelling at more than a relatively low speed (and -10-typically 5 mph -about 8 km/h) the ECU will not remove the digital signal from the controller of the fuel supply valve 17 nor inhibit the operation of the EMS, until the vehicle is at rest once more.

In normal operation, a driver of the vehicle merely has to have the token 13 about his person, in order to allow use of the vehicle in an entirely conventional manner. Initially the immobiliser is in its stage 1 (Figure 4), with the engine off, the three vehicle systems disabled and the warning light showing green. When a driver having the correct token wishes to drive the vehicle, the ECU is energised and the initial synchronisation sequence referred to above is performed. The presence of the associated token 13 is detected by the ECU, which enables all three systems, and in particular supplies the required coded digital signal to the controller of the valve 17, to energise the solenoid thereof. The immobiliser is currently off and the warning light 19 shows green. The engine may therefore be started and the vehicle driven.

Should the driver stop the engine and then walk away from the vehicle, the system returns to stage 1.

In the event that the engine is started and then the token is moved out of range, the immobiliser will switch to stage 2 (Figure 4) on the next issue of an interrogation request by the ECU, the warning light then showing red and yet the engine continues operation. So long as the vehicle is not moving, depression of the accelerator pedal will cause the ECU to issue another interrogation request and if it fails to receive the required coded signal, the ECU will immediately switch the immobiliser to stage 1 -that is, fully active and with all three systems disabled. If the accelerator pedal is not depressed the engine may continue running; when the token is moved back into range the accelerator pedal may thereafter be depressed. This causes the ECU to issue an interrogation request and the ECU should then receive the correct coded signal back from the token. The ECU will switch the warning light to show green once more and the vehicle may be driven.

Once the vehicle is underway, should the token then be moved out of range, or otherwise the signal from the token be lost such as in the event that the token internal battery becomes exhausted, the ECU takes no action other than to note the token signal is not in range and also change the state of the warning light 19 to red. However, as soon as the vehicle speed reaches zero, the immobiliser switches to stage 1, and disables all three vehicle systems.

The various operations of the system as described above are shown in the flow chart of Figure 3 and in the truth table of Figure 4.

The above-described embodiment utilises a token having an active transmitter including an electrical power source. It would be possible to have a passive token in the form of a responder, which reacts to a signal received from the ECU. In this case, the ECU will include a transmitter and a receiver, to transmit a coded signal to the token and then monitor for reception of a responder signal.

Claims

CLAIMS

1. Engine control apparatus for a vehicle engine, comprising an engine fuel valve including an electrical actuator requiring a pre- defined data signal to effect operation of the valve, an electronic module including a radio frequency receiver and arranged to control the supply of said data signal to the fuel valve, and a portable token having a radio frequency transmitter arranged to transmit a token signal for detection by the receiver of the electronic module, whereby the state of the fuel valve may be controlled by the electronic module dependent upon reception of the token signal.

2. Engine control apparatus as claimed in claim 1, wherein the fuel valve has an open state and a closed state, and the electrical actuator is arranged to operate the valve to its open state or maintain the valve in its open state only on reception of a corresponding data signal from the electronic module.

3. Engine control apparatus as claimed in claim 1 or claim 2, wherein the fuel valve comprises a solenoid valve together with an integral electrical controller to which is supplied said data signal, the valve being spring-urged to its closed position.

4. Engine control apparatus as claimed in claim 2 or claim 3, wherein the fuel valve is arranged to close if any one of said data signal, an electrical power supply line or an electrical earth is absent at the valve electrical actuator.

5. Engine control apparatus as claimed in any of the preceding claims, wherein connections to the electrical actuator of the fuel valve are incorporated in a chamber provided in a body or housing for the valve, said connections being embedded in a potting compound furnished in the chamber.

6. Engine control apparatus as claimed in any of the preceding claims, wherein the electronic module includes a speed input for a vehicle speed-related signal and the data signal supplied to the fuel valve depends upon the signal supplied to said speed input.

7. Engine control apparatus as claimed in claim 6, wherein the electronic module is arranged to inhibit closing of the fuel valve if the speed input indicates a speed in excess of a pre-set value.

8. Engine control apparatus as claimed in any of the preceding claims, wherein the electronic module includes a pedal input for a signal dependent upon depression of the accelerator pedal associated with the engine, and the data signal supplied to the fuel valve depends upon the signal supplied to said pedal input.

9. Engine control apparatus as claimed in claim 6, wherein the electronic module is arranged to close the fuel valve if there is a signal indicative of pedal depression in the event the engine is running and the token signal is not received by the control module.

10. Engine control apparatus as claimed in any of the preceding claims, wherein the token is arranged to transmit a coded token signal the coding of which is changed each time a coded signal is transmitted, or after the transmission of a pre-set number of coded signals.

11. Engine control apparatus as claimed in claim 10, wherein the changing of the coded token signal follows a pre-set sequence pre-loaded into the token and the electronic module.

12. Engine control apparatus as claimed in any of the preceding claims, wherein both the electronic module and the token comprise co-operating -14 -receiver/transmitter pairs and the token transmits a coded signal only following receipt of an interrogation request transmitted by the electronic module.

13. Engine control apparatus as claimed in any of the preceding claims and for use with an engine having an electronic engine management system, in which the control module is arranged for connection to the electronic engine management system to inhibit engine operation in the event the token signal is not detected by the electronic module.

14. Engine control apparatus as claimed in any of the preceding claims, wherein the electronic module is arranged for connection to the engine starter circuit to inhibit the operation thereof in the event the token signal is not detected by the electronic module.

15. Engine control apparatus for a vehicle engine and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

16. A method of controlling the operation of a vehicle engine provided with an engine fuel valve including an electrical actuator requiring a pre-defined data signal to effect operation of the valve, an electronic module including a radio frequency receiver and arranged to control the supply of said data signal to the fuel valve, and a portable token having a radio frequency transmitter arranged to transmit a token signal for detection by the receiver of the electronic module, in which method the fuel valve is set to a closed state in the event that the electronic module fails to detect the token signal transmitted by the token transmitter.

17. A method as claimed in claim 16, wherein the electronic module senses vehicle speed and in the event the engine is running and the token signal is not -15-detected by the electronic module, the closing of the fuel valve is inhibited if the sensed vehicle speed is greater than a preset minimum value.

18. A method as claimed in claim 17, wherein should closing of the fuel valve be inhibited because the vehicle speed is greater than the preset minimum value, the fuel valve is not closed until the vehicle speed has once more become less than the preset minimum speed or essentially zero.

19. A method as claimed in any of claims 16 to claim 18, wherein the electronic module senses accelerator pedal depression and in the event the engine is running and the token signal is not detected by the electronic module, the fuel valve is closed should the accelerator pedal be depressed.

20. A method as claimed in any of claims 16 to 19, wherein the token transmits a coded token signal the coding of which is changed each time a coded signal is transmitted, or after the transmission of a pre- set number of coded signals.

21. A method as claimed in claim 20, wherein the changing of the coded token signal follows a pre-set sequence pre-loaded into the token and the electronic module and the electronic module determines the presence of the token signal only if the detected signal changes in accordance with the pre-set sequence.

22. A method as claimed in any of claims 16 to 21, wherein both the electronic module and the token comprise co-operating receiver/transmitter pairs and the token transmits a coded signal only following receipt of an interrogation request transmitted by the electronic module. -16-

23. A method of controlling the operation of a vehicle engine and substantially as hereinbefore described with reference to the accompanying drawings.

24. A vehicle having an engine whenever provided with control apparatus according to any one of claims 1 to 15 or whenever the engine is controlled by a method according to any one of claims 16 to 22.