Device and method for preventing unauthorized starting of a vehicle

The present invention relates to a device and method for preventing unauthorized starting of a vehicle.

In the prior art devices are known that prevent vehicles from starting, to exclude the possibility of unauthorized use, for example to prevent theft. Such devices are usually based on an identification/authentication procedure in which, when the key is inserted into the vehicle's ignition switch, to start the engine, data are exchanged between the ignition key and a control module incorporated in the vehicle. If the module validates and enables the key, the engine can be started, otherwise it cannot.

The key incorporates an electromagnetic device, known as a "transponder", that is activated when in proximity to the control module, with which it exchanges a secret identification code (electronic key).

Once the key has been enabled/validated the control module allows the fuel to be delivered to the engine so that it can start.

These known enabling procedures are still not able to guarantee an adequate level of security, since it may be possible to find other ways of starting the vehicle even without using the proper ignition key.

The purpose of this invention is to overcome all the drawbacks (solve the problems) described above and providing a device and method for preventing unauthorized starting of a vehicle so that it is possible to extend the level of control and immobilize the vehicle more effectively, by controlling all the electronic circuits that manage vehicle kinematics functions, not only when the vehicle is parked and/or the engine is not running, but also once the engine has been started, so as to control the management of the vehicle motion, propulsion and additional braking.

An object of the present invention is a device for preventing unauthorized starting of a vehicle, that comprises means for authenticating an ignition key, characterized in that it comprises a control means that determines the activation of the propulsion functions, and the control of the motion and of additional braking systems on the basis of said authentication of the ignition key.

In particular this invention relates to a device and method for preventing unauthorized starting of a vehicle, as better described in the claims, which are an integral part of this description.

The purposes and advantages of this invention will become clear from the following detailed description of a preferred embodiment and of its variants and from the drawings that are attached hereto, which are merely illustrative and not limitative, in which: <ul id="ul0001" list-style="none" compact="compact"><li>figure 1 is a block diagram of the device according to this invention;</li><li>figure 2 is an operational flow chart of the method according to the present invention.</li></ul>

In fig.1 VCM indicates the immobilizer module according to the present invention.

The VCM consists of an electronic device that communicates with an ignition key KEY.

The procedure uses a conventional transponder link to identify and enable the key. Each KEY is identified by means of a unique code that is stored in the VCM during manufacturing, thus creating an univocal association between a given number of keys and the VCM of a vehicle.

Whether or not the KEY is identified as valid determines whether a series of functions, which are described below, are enabled or disabled.

The VCM controls the operation of a module ECM that manages the delivery of fuel to the engine. The VCM enables operation of the ECM if the ignition KEY is identified as valid.

The modules VCM and ECM dialogue via a conventional encrypted protocol according to the SAE J1939/71 standard, using a "challenge/response" technique to exchange messages.

The VCM manages the functioning of the engine brake FM and of the module INT that manages the vehicle's additional braking systems: the INT controls the electric braking systems, such as the hydraulic or electromagnetic retarder.

The VCM manages requests to activate the engine brake FM and the module INT. If the KEY is not identified as valid, the VCM blocks the additional braking systems in the braking position so that the vehicle cannot move.

When the accelerator pedal ACC is operated, the VCM uses a torque map to control the amount of engine torque requested, where torque = f (Engine Speed, Accelerator Pedal Position), called the Driveability map. The request for torque is managed by the VCM, which only allows torque to be transmitted if the key has been identified as valid. The torque map is stored in the VCM.

The VCM manages requests for engine torque from the transmission system TRM (basically the clutch, gearbox). If the KEY is not identified as valid, the VCM blocks the torque control requests from the Transmission Control module to engage the gears and open/close the clutch, thus preventing gear change. This control function is enabled in case of an automatic transmission system.

The VCM enables the activation of the starting motor (cranking) CRK, which is blocked if the KEY is not identified as valid.

The VCM controls an electronic control module BDY that manages the control functions of the electric circuit, such as lights, electric windows, etc. If the key is not identified as valid, the BDY activates the horn and/or hazard warning lights.

If the key is not identified as valid, the VCM enables the use of an emergency starting procedure, which is also used in case of problems, for example if the key is lost or broken.

In that case, a manual starting procedure is performed by entering an unblocking PIN code from the instrument panel (keypad on the steering wheel). Only the driver knows this code, which is previously stored in the VCM.

In this case, when the correct PIN code is entered the control module enables all vehicle functions, in exactly the same way as when the KEY is identified as valid.

From the description set forth above it is apparent that the main characteristic of the device (VCM) for preventing unauthorized starting of a vehicle, according to this invention, consists of determining the activation of the vehicle's propulsion functions and the management circuits of the power transmission and motion control and additional braking systems on the basis of the authentication of the ignition key (KEY).

The person skilled in the art will have no difficulty in embodying the module VCM on the basis of the functions described above. The VCM comprises a series of shut-off functions that are controlled on the basis of the authentication of the KEY.

Such functions may be embodied by means of a program, for example written in C language, using a normal automotive software system.

As regards the illustration of the method of operation, reference is made to the operational flow chart in figure 2, which is useful for describing the method of vehicle immobilization according to the present invention.

In the first phase 1 the KEY authentication procedure is carried out.

If the key is authenticated (phase 2 - YES), the VCM authorizes all the systems controlled thereby to become fully operational (phase 3), and thus: <ul id="ul0002" list-style="dash" compact="compact"><li>the starting motor CRK is unblocked;</li><li>the fuel delivery system ECM is unblocked;</li><li>the transmission system TRM is unblocked and fully operational;</li><li>the management circuits of the engine brake FM and additional braking system INT are unblocked;</li><li>all functions in connection with the use of the accelerator pedal ACC to request torque are unblocked;</li><li>the hazard warning lights and the acoustic alarm of the electronic control module BDY are not activated;</li></ul>

If the key is not authenticated (phase 2 - NO), the VCM enables the use of the emergency starting procedure (phase 4 in which the PIN code can be entered to unblock the system manually).

If the PIN code is not entered, or if the PIN code is incorrect after a maximum number of attempts (phase 5 - NO), the VCM immobilizes the vehicle (phase 6), and thus: <ul id="ul0003" list-style="dash" compact="compact"><li>the starting motor CRK is blocked;</li><li>the delivery of fuel to the engine ECM is blocked; requests for torque from the transmission system TRM are blocked; the request for torque from the accelerator pedal ACC is blocked; the engine brake FM and additional braking system INT are activated;</li><li>the hazard warning lights and acoustic alarm are activated.</li></ul>

Alternatively, if the PIN code is entered correctly (phase 5 - YES), the system acts in exactly the same way as when the KEY is identified as valid, and goes to the phase 3 described above.

In the unlikely event of the vehicle's engine being started in a fraudulent manner, even though the ignition KEY has not been authenticated, i.e. by bypassing the KEY and PIN code validation procedures, the VCM is able to switch to a degraded operation mode (phase 7) in which for example the VCM only allows the accelerator ACC to request minimum engine torque, limiting the number of engine revolutions (e.g. maximum 1000 RPM), and/or may only authorize the transmission module TRM to enable engagement of the 1^st gear, and/or may activate the vehicle's braking system.

This invention can be implemented advantageously in a computer program comprising program code means for performing one or more steps of such method, when such program is run on a computer. For this reason the patent shall also cover such computer program and the computer-readable medium that comprises a recorded message, such computer-readable medium comprising the program code means for performing one or more steps of such method, when such program is run on a computer.

It will be apparent to the person skilled in the art that other alternative and equivalent embodiments of the invention can be conceived and reduced to practice without departing from the scope of the present invention.

It will be possible for the person skilled in the art to embody the invention without introducing any further construction details.