IMMOBILISER DEVICES FOR ENGINES OR VEHICLES

Abstract: An immobiliser device is provided for an engine or vehicle having a wiring loom (12) with a first connector (10) which is connectable to a complementary second connector (18) of an essential unit (20) for the engine or vehicle. The immobiliser device comprises a housing (34) which can be permanently attached by epoxy resin to the first connector whilst still permitting the first connector to be connected to the second connector, and a circuit (42) which normally disconnects and/or shorts at least one (24A) of the wires of the wiring loom adjacent the first connector and which can be disabled by an authorised user of the vehicle to connect the wire and/or remove the short.

Description: TITLE Immobiliser Devices for Engines or Vehicles. DESCRIPTION This invention relates to immobiliser devices and to engines and vehicles having such devices. The invention was originally conceived for use with motorcycles, but is also applicable to other vehicles and to engines in general. Many immobiliser devices are on the market, and typically they include a hidden, remotely- controllable switch in an essential circuit for the engine (such as a starter circuit or ignition circuit) and a remote control (such as a key-pad, or infrared or radio transmitter) which can be operated by an authorised user to control the switch to enable the circuit. Such devices provide a significant deterrent to motor car thieves. While a skilled thief may be able to override the immobiliser device, it takes time and increases the risk of being caught in the act. The thief is therefore inclined to try an easier target (or even, one might like to believe, give up their criminal activities). However, these devices to not provide as much of a deterrent to motorcycle thieves. Firstly, it is not so easy to hide the switch on a motorcycle. Secondly, and probably more significandy, the motorcycle can be loaded into a van (after any chains or shackles have been released or cut) and taken to a place where the thief can work in privacy at overriding the immobiliser device. A first aspect of the present invention is aimed at improving the effectiveness of immobiliser devices, particularly but not exclusively for motorcycles. In accordance with the first aspect of the invention, there is provided an immobiliser device for an engine or vehicle having a wiring loom with a first connector which is connectable to a complementary second connector of an essential unit for the engine or vehicle, the immobiliser device comprising means for permanently attaching the device to the first connector, and a circuit which normally disconnects and/or shorts at least one of the wires of the wiring loom and which can be disabled by an authorised user of the vehicle to connect the wire and/or remove the short. In this specification, the term "essential unit" is intended to mean a unit whose operation is essential to the starting and/or running of the engine or vehicle, for example an ignition unit, fuel- injection control unit, starter motor, fuel pump, hydraulic pump or essential electrical relay. Also, in this specification, the term "permanently attached" with reference to the device and the first connector is intended to mean that they are attached so strongly that it is not possible to detach them without causing significant damage to the connector, and with reference to the device and essential unit (see below) is intended to mean that they are attached so strongly that it is not possible to detach them without causing significant damage to the essential unit. This first aspect of the invention is particularly effective because: (1) the majority of motorcycles which are put on the market these days have a "designer" connector on the wiring loom for connection to the ignition unit, i.e. the connectors are not readily-available general-purpose connectors; (2) it is almost unheard of for the connector per se to fail, and they are therefore virtually unobtainable, except as part of a complete wiring loom; (3) the wiring looms of many modern motorcycles are very complex and accordingly very expensive. In view of this, it is believed that the present invention will provide a greater deterrent to thieves than the conventional immobilisers. In one embodiment of the in vention, the device is permanently attachable to the first connector, whilst still permitting the first connector to be connected to the second connector, and the circuit is connectable to at least one of the wires of the wiring loom adjacent the first connector. In this case, the device preferably has first and second insulation displacement connectors for connecting to said one wire at spaced positions therealong, and means for cutting said one wire between the spaced locations. This makes the fitting of the device extremely easy. The device preferably further comprises a housing for engaging the first connector and through which the wires of the wiring loom can pass and for containing the circuit, and the means for permanently attaching the device to the first connector preferably comprises a filler for filling the housing and bonding the first connector and the wires of the wiring loom to the housing. The filler can therefore provide protection of the circuit against the elements, whilst at the same time reinforcing the housing and making it impossible to remove the device without damaging the first connector and/or the wires of the loom. In another embodiment of the invention, the device comprises a third connector which is complementary to and permanentiy attachable to the first connector, and a fourth connector which is connected to the third connector and which is complementary to and connectable to the second connector, and wherein the circuit is connected between the third and fourth connectors. This also makes the fitting of the device extremely easy. In this case, the means for permanently attaching the device to the first connector preferably includes a plurality of barbs on the third connector for lockingly engaging with the first connector and/or adhesive for bonding the third connector to the first connector. The device may be provided in the form of a kit of parts for fitting to the first connector and connection to the wiring loom. However, although the invention was originally conceived as a retrofit device, the device may be supplied as original equipment. It is then possible for a manufacturer to determine from their records the bona fides of a request for the supply a replacement connector or wiring loom. In accordance with a second aspect of the present invention, there is provided an essential unit for an engine or motor vehicle, in combination with an immobiliser device permanentiy attached to the essential unit, the essential unit having at least one wire connectable to the engine or vehicle, and the immobiliser device comprising a circuit which normally disconnects and/or shorts that wire and which can be disabled by an authorised user of the vehicle to connect the wire and/or remove the short. This aspect of the invention is particularly (but in no way exclusively) applicable to marine outboard engines. The electrical connections to one popular type of ignition unit for such engines are by way of flying leads extending out of the ignition unit. In this case, the immobiliser device is connected so that it normally disconnects and/or shorts at least one of the flying leads which is critical to the operation of the essential unit. The deterrent provided by this second aspect of the invention may be increased by the manufacturers of the essential units applying serial numbers or the like thereto, keeping records of sales, and only supplying replacement units if the original unit is returned and the details of the prospective purchaser of a replacement unit agree with the records for the serial number on the returned original unit. Specific embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a top view of a conventional type of wiring loom connector for connection to an ignition unit of a motorcycle; Figure 2 is a front view of the connector of Figure 1 ; Figure 3 is a side view of the connector of Figure 1 ; Figure 4 is sirnilar to Figure 1 , but with part of an immobiliser device of one embodiment of the invention attached to the connector, and with part of a housing of the immobiliser device cut-away as indicated by dot-dash lines; Figure 5 is a side view of the connector and immobiliser device of Figure 4; Figure 6 is a rear view of the connector and immobiliser device of Figure 4; Figure 7 is a circuit diagram of the immobiliser device of Figure 4; and Figure 8 is similar to Figure 4, but showing another embodiment of the invention. Referring to Figures 1 to 3 and 7, a connector 10 is attached to part of a motorcycle wiring loom 12. The connector comprises a block 14 of tough plastics material which has keys, key ways, chamfers or the like 16 which mate with complementary formations on a connector 18 of a motorcycle ignition unit 20. The connector 10 also has seven female terminals 22 each connected to a respective wire 24 of the loom 12 and for connection with corresponding male terminals 26 of the ignition unit connector 18. One of the female terminals 22A is connected to a wire 24 A of the loom 12 carrying switched positive. Referring now to Figures 4 to 7, the immobiliser device of the first embodiment of the invention comprises a connector unit 28, and master and slave transponder units 30, 32. The connector unit 28 comprises a housing 34 which is specially shaped to fit, at the left-hand side as seen in the Figure 4, the rear of the block 14 of the connector 10 with the end portions of the wires 24 of the loom 12 extending through the housing and exiting through an aperture 36 as seen in Figure 6. The housing 34 has a split 38 along one of its side walls so that, when it is being fitted to the connector block 14, it can be prised apart as shown by the arrows 40 in Figure 6 to enable the wires 24 of the loom 12 to be passed through the resulting gap. The housing 34 contains a printed circuit board (PCB) 42 on which are mounted a pair of insulation displacement connector (IDC) elements 44, 46, which are arranged and aligned to cut into the insulation of the switched positive wire 24a and make electrical connection therewith as the connector unit 28 is fitted to the connector block 14. Between the IDC elements 44, 46 is an insulating blade 48 which is arranged and aligned to cut through the insulation and the conductor of the switched positive wire 24a as the connector unit 28 is fitted to the connector block 14. In order to fit the connector unit 28 to the connector block 14, the connector block 14 and the wires 24 running into it are firstly cleaned, and their surfaces are preferably roughened either using an abrasive or a chemical. A thin coating of epoxy resin is then smeared over the rear of the connector block 14. The split 38 of the casing 34 of the connector unit is then prised apart and the wires 24 are passed through the gap so that they extend through the casing 34. The IDC elements 44, 46 and the insulating blade 48 are then aligned with the switched positive wire 24a, and the upper and lower faces of the casing 34 are squeezed together in order to sever the switched positive wire 24a and connect the IDC elements 44, 46 to respective severed ends of the wire 24a. The casing 34 is then oriented with its rear face upwards, and epoxy resin 50 is poured into the aperture 36 so as to fill the casing 34. When the resin has cured, the internal components of the connector unit 28 are potted in the resin, and the resin permanently bonds itself and the casing to the connector block 14 and the wires 24. Referring in particular to Figure 7, the PCB 42 also carries a relay 52 having a coil 52a and a single-pole normally-open contact 52b, a pair of diodes 54, 56 and a known immobiliser device circuit 58. The IDC element 44 is connected to one side of the relay contact 52b, to a positive power supply terminal of the circuit 58, and also supplies power through a cable 60 to the master transponder unit 30. The connector unit 28 has its own earth wire 62 which is connected to the earth of the motorcycle. (Alternatively, a further IDC element could be provided to connect, inside the connector unit 28, to one of the wires 24 which is earthed.) The earth wire 62 is connected to one side of the relay coil 52a, to a negative power supply terminal of the circuit 58, and through the cable 60 to the master transponder unit 30. The circuit 58 has a data terminal which is furthermore connected through the cable 60 to the master transponder unit 30. The circuit 58 also has an output terminal which is connected to the other side of the relay coil 52a. The other side of the relay contact 52b is connected to the IDC element 46. The master transponder unit 30 would typically be mounted adjacent the ignition switch of the motorcycle, and the slave transponder unit 32 would typically be carried on the motorcycle owner's key-ring 64. The operation of the circuitry is as follows. When the motorcycle ignition is turned off, the circuitry described above is not powered up. When the ignition switch is turned on, a voltage appears on the switched-positive wire 24a, which powers up the circuit 58 and the master transponder unit 30, but this, in itself, does not cause the circuit 58 to close the relay 52, and so the ignition unit 20 is inoperative. When the master transponder unit 30 is powered up, it repeatedly transmits bursts of low-power radio-frequency energy which are received, rectified and stored by the slave transponder unit 32, if it is close enough to the master transponder unit 30. Between the transmitted bursts, the slave transponder unit 32 uses the stored energy to transmit a low-power radio-frequency coded identity signal having 128 data bits (thus providing 2 128 , i.e. over 340 x 10 36 permutations), and this signal is received by the master transponder unit 30, demodulated, amplified, and passed to the data terminal of the circuit 58. The circuit 58 then compares the identity of the coded signal with a stored identity, and only if they agree it applies a voltage to its output terminal which energises the relay coil 52a, closes the relay contact 52b and thereby powers up the ignition unit 20. The motorcycle can then be started. The diode 54 is included to make the relay self-latching but without loading the circuit 58 with the load impedance of the ignition unit 20. Thus, once the relay contact 52b closes, voltage can be supplied via the contact 52b and the diode 54 to the relay coil 52a to keep the relay contact 52b closed even if the circuit 58 ceases to provide voltage to the relay coil. This therefore prevents the motorcycle engine cutting-out if, for example, the motorcycle is subjected to radio interference which prevents the proper operation of the transponder units 30, 32. Of course, once the motorcycle ignition is turned-off , the voltage disappears from the switched-positive wire 24a, and the circuitry resets. The diode 56 is included to protect the circuit 58 from spikes from the relay coil 52a when it is de-energised. A second embodiment of the invention will now be described with reference to Figure 8, which shows a connector unit 28 which is similar in many respects to that described above with reference to Figures 4 to 7, except that it has its own female connector 66 which complements the male connector of the ignition unit and can be releasably connected thereto, and its own male connector 68 which complements the connector 10 of the wiring loom 12. The terminals of the connectors 66, 68 are connected inside the connector unit 28 one-to-one, with the exception of the terminals for the switched-positive wire, which are connected via the contacts of a relay in a circuit similar to that shown in Figure 7. In use, the connector block 14 of the wiring loom connector 10 is permanentiy connected to the connector 68 of the connector unit 28 so that they cannot be separated without damaging the connector 10 to such an extent that it cannot be used to make a reliable direct connection to the male connector of the ignition unit in place of the connector 66. The permanent connection may rely solely on an adhesive, after the surfaces to be bonded have been suitably cleaned and prepared. Alternatively, or preferably additionally, the connector 68 may include barbs in the nature of a "Chinese finger trap" which bite into the connector block 14 so that separation of the connectors 10, 68 will result in the connector 10 being damaged to such an extent that it becomes unusable. To assist in this, the immobiliser device may be supplied with a tool which is specially designed to cut a ridge around the connector block 14 into which the barbs fit. A third embodiment of the present invention will now be described. In this embodiment, an ignition unit for a marine outboard engine has a plurality of flying leads extending out of the ignition unit. An immobiliser device which has an electrical arrangement similar to that described above with reference to Figures 4 to 7 is permanently attached to the control unit, and is connected so that it normally disconnects one of the wires which is critical to the operation of the ignition unit. The ignition unit is marked by the manufacturer with a serial number. The manufacturer can keep records of sales of the ignition units. Then, when a prospective purchaser orders a replacement unit, the manufacturer can demand the return of the original unit and only supply a replacement unit if the details of the prospective purchaser agree with the records for the serial number on the returned original unit. It will be appreciated that many modifications and developments may be made to the embodiments described above, which are given by way of non-limiting example, without departing from the invention.

Claims: CLΔJMS 1. An immobiliser device for an engine or vehicle having a wiring loom (12) with a first connector (10) which is connectable to a complementary second connector (18) of an essential unit (20) for the engine or vehicle, the immobiliser device comprising means (50) for permanently attaching the device to the first connector whilst still permitting the first connector to be connected to the second connector, and a circuit (42) which normally disconnects and/or shorts at least one (24A) of the wires of the wiring loom adjacent the first connector and which can be disabled by an authorised user of the vehicle to connect the wire and/or remove the short. 2. A device as claimed in claim 1 , and having first and second insulation displacement connectors (44, 46) for connecting to said one wire at spaced positions therealong, and means (48) for cutting said one wire between the spaced locations. 3. A device as claimed in claim 1 or 2, further comprising a housing (34) for engaging the first connector and through which the wires of the wiring loom can pass and for containing the circuit, and the means for permanently attaching the device to the first connector comprises a filler (50) for filling the housing and bonding the first connector and the wires of the wiring loom to the housing. 4. A device as claimed in any preceding claim, and provided in the form of a kit of parts for fitting to the first connector and connection to the wiring loom. 5. An engine or vehicle having a wiring loom (12) with a first connector (10) which is connectable to a complementary second connector (18) of an essential unit (20) for the engine or vehicle, and an immobiliser device as claimed in any preceding claim permanently attached to the first connector. 6. A vehicle as claimed in claim 5, in the form of a motorcycle. 7. An engine or vehicle as claimed in claim 5 or 6, wherein the essential unit is an ignition unit (20), fuel-injection control unit, starter motor, fuel pump or essential electrical relay.

Inventors: PARFITT GWYN DAVID WALTER, STULZ ANDREAS, PARFITT, GWYN, DAVID, WALTER, STULZ, ANDREAS
Applicants: O E M PROJECT MANAGEMENT LTD, PARFITT GWYN DAVID WALTER, STULZ ANDREAS, O.E.M. PROJECT MANAGEMENT LIMITED, PARFITT, GWYN, DAVID, WALTER, STULZ, ANDREAS
Application year: 1996
Main classification: B60R25
IPC codes: B60R25, F02B61, F02D45