Abstract:
A system for preventing inadvertent operation of remote keyless entry commands for a vehicle remote keyless entry system having a user interface located on the head of the vehicle ignition key. Whenever the ignition key is about to or has been inserted into the vehicle ignition, the user may inadvertently depress one or more of the command buttons of the keyhead. This accidental depression may occur before or during inserting the key, or after the key has been inserted and the key is being turned to activate the ignition. The system of the present invention selectively inhibits the vehicle from acting upon the commands when it is believed any of these situations may be occurring.

Description:
RELATED APPLICATIONS 
     This application claims priority from U.S. provisional application No. 60/099,573, filed Sep. 9, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to vehicle remote control, anti-theft or immobilizing systems and, more particularly, to a remote control key system having a key that incorporates remote control functions and immobilization features into the keyhead of the key and which prevents operation of the remote control functions at certain times. 
     BACKGROUND OF THE INVENTION 
     A conventional remote keyless entry (RKE) transmitter is generally in the form of keyfob that hangs from a key ring. Typical RKE transmitters include a plurality of buttons or switches which, when depressed, initiate corresponding vehicle control functions remotely. For example, RKE transmitters may include four buttons: a door lock button for locking the vehicle doors, a door unlock button for unlocking the vehicle doors, a trunk release button for releasing the vehicle trunk, and a panic button for sounding the horn of the vehicle and/or flashing the vehicle&#39;s lights to draw attention to the vehicle. 
     In addition to the convenience offered by RKE transmitters, anti-theft systems are commonly employed to immobilize a vehicle. A popular anti-theft system utilizes a transponder embedded in a keyhead portion of a key and a receiver located at the ignition lock. When the key is placed in the ignition lock, and if the identifying signal transmitted by the transponder and received by the receiver is determined not to be a match a preset identifying code stored at the vehicle, an immobilizing system is activated to prevent operation of the vehicle. 
     Integration of both the immobilizer system and the RKE system into a keyhead of a vehicle key has been proposed. However, when RKE buttons are integrated into a keyhead, there is a risk of pushing a transmitter button while turning the keyhead in the ignition lock, inadvertently initiating a vehicle control function. One approach to overcome this problem is to disable the RKE system as soon as the key is in the lock of as soon as the key is turned to the accessory or ignition position. However, even when these measures are taken, there is still a possibility of inadvertently pushing a transmitter button just before inserting the key into the lock or before turning the key to the ignition position and, in so doing, initiating a control function at an inappropriate time. 
     Accordingly, when RKE functions are provided in a keyhead of a vehicle key, there is a need to provide a means of preventing inadvertent RKE operations when the key is being handled to start the engine of the vehicle. 
     SUMMARY OF THE INVENTION 
     The present invention fulfills the need described above by providing a remote control system for a vehicle. The system includes a key having a keyplate to be received in the vehicle&#39;s ignition lock and a keyhead coupled to the keyplate. At least one switch is on the keyhead to be digitally actuated to initiate a control function of the vehicle remotely. Transmission structure is disposed in the keyhead and is associated with the switch to transmit an atmospheric propagation signal containing an identification code. Receiving structure, located on the vehicle, receives the atmospheric propagation signal. A controller, provided on the vehicle, outputs a control signal for effecting the control function associated with the switch on the keyhead. Sensing structure, associated with the controller, indicates when a driver of the vehicle is in position to operate the vehicle. The controller prevents the control function form occurring upon actuation of the at least one switch when the sensing structure indicates that a driver is in position to operate the vehicle, this includes the times both prior to, during and immediately following insertion of the keyplate into the ignition lock. 
     In another aspect of the invention, the keyhead further includes a transponder having an associated code. The ignition lock includes a receiver associated with the controller. The controller compares a coded signal sent by the transponder and received by the receiver with a set point signal. If the coded signal matches the set point signal, the controller permits ignition to occur and, if the coded signal does not match the set point signal, the controller initiates a vehicle immobilizing system. The controller prevents control functions from occurring when communication between the transponder and the receiver can occur. This prevention may take effect before, during or after insertion of the key into the ignition lock. 
     Method of preventing inadvertent operation of remote keyless entry functions when a user is in position to operate the vehicle are also provided. 
     Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts, and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawing, all of which form a part of this specification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a block diagram of a remote control key system provided in accordance with the principles of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIG. 1, a remote control key for use with a remote control system, provided in accordance with the principles of the present invention, is shown generally indicated at 10. FIG. 1 is a schematic block diagram of an electrical arrangement wherein a remote control key, generally indicated at  12 , is formed of a key plate  14  and a keyhead  16 . Keyhead  16  includes transmission structure in the form of a built-in transmission circuit  18 . In accordance with the principles of the present invention, the keyhead  16  is provided with a locking switch  20 , an unlocking switch  22 , a panic switch  24 , and trunk release switch  26 . Such keyheads and their associated vehicle systems are commonly referred to as Remote Keyless Entry, or RKE, systems. As is well understood by those of ordinary skill in the art, the switches of an RKE system need not be configured as shown in FIG. 1, but may be positioned on keyhead  16  in any suitable configuration. Furthermore, more or fewer switches associated with other or different functions may be provided within the scope of the present invention. 
     As illustrated in this embodiment, when one of the switches  20 - 26  is depressed by a user, one of four signals is sent. There is a locking signal, an unlocking signal, a trunk release signal, and an alarm signal. Each signal may be comprised of a string of binary digits. The appropriate signal is transmitted remotely from the transmission circuit  18 . In the present embodiment, the signal is atmospherically propagated, and may take the form of either an infrared signal or radio transmission. However, other means of communicating may be used. Each signal, or message, may further contain an associated identification (or “ID”) code. Each ID code represents one or more binary digital signals and is set for a particular vehicle. The ID codes associated with systems of the present invention include, without limitation, rolling codes (in which more than one, e.g., 500, codes are authorized by the vehicle), as well as encrypted codes. In addition, the same ID code is stored by the vehicle so as to enable authentication of transmitted signals, as more fully described below. 
     An RKE receiver/body unit  30  (which may be referred to below as “controller” or “control unit”  30 ) defines a controller and includes a processor, such as a microprocessor, microcomputer, or similar device. Within this controller resides one or more memories or registers. These registers preferably contain the binary codes for the RKE action signals, which in this embodiment are door lock, door unlock, trunk release and panic alarm activate. These action signals may be commonly referred to also as RKE functions or commands. The registers of the controller  30  preferably also include the vehicle-specific ID code. The ID code contained in the control unit  30  must match that of the ID code sent by the transmitter  18  in order for the action signals, or commands, to be acted upon. The control unit  30 , as described here, is provided separately from, but may be associated, with an engine control unit (which may be part of immobilizing system  33 , described below). Alternate suitable configurations of the vehicle controllers consistent with the functionality described herein are also contemplated and covered by the present invention. 
     In the illustrated embodiment, the keyhead  16  also includes a built-in transponder  28 , which may, without limitation, be a transponder capable of supporting encryption algorithms (e.g., a crypto transponder system). A user-specific code is stored in memory in the transponder  28 . In the illustrated embodiment, the transponder  28  is of the type disclosed in U.S. Pat. No. 5,729,057, the content of which is hereby incorporated by reference into the present specification. Thus, a receiver in the form of an antenna  31  is preferably disposed around a lock cylinder of an ignition lock (not shown). When the key plate  14  comes into proximity of or is introduced into the ignition lock, the control unit  30  generates a question or start signal that is transmitted through the antenna  31  to the transponder  28 . The transponder  28  thereupon responds with a coded answer signal. The coded answer signal is received by the antenna  31 , sent to the control unit  30 , and evaluated by the control unit. The answer signal is compared with a stored code in the control unit  30  and, if the two codes do not correspond, an immobilizing system  33  in the vehicle is turned on. The immobilizing system  33  is designed to inhibit the starting of the vehicle. As can be appreciated by those of ordinary skill in the art, the immobilizing system  33 , or immobilizer, may contain or otherwise be associated with an engine control unit. It may also be an ignition coil, a starter, a shut-off valve or the like. The immobilizing system  33  serves to permit starting of the vehicle&#39;s engine only when authorization is proved. As such, the immobilization feature herein described may also take the form of simply preventing the ignition from communicating the signal necessary to start the engine. As such, the immobilizer would take the form of the engine ignition system normally being in the inhibited state, and the system changing to the enabled state only upon authentication between the transponder  28  and the control system  30 . The transponder  28  and the controller  30 , via its receiver antenna  31 , may communicate, without limitation, via infrared or radio transmission or by inductively coupled coils (which may be characterized, for example, by transmission at 125 kHz). 
     The transponder  28  is configured such that communication between it and the antenna  31  occurs only when the key containing the transponder  28  is sufficiently near or in the ignition lock. This configuration could be achieved by limiting the receiving range of the transponder  28  or by enabling it to communicate only if the received signal strength from the receiver antenna  31  is below a preselected threshold. 
     If vehicle immobilization is not desired, the transponder  28  need not be provided in the keyhead  16  and the ignition lock need not contain antenna  31 . Or, alternatively, the transponder  28  and antenna  31  may still be provided, but the immobilization system  33  may be omitted. In that way, the transponder  28  and antenna  31  would still be available for use in selectively inhibiting RKE functions as described in greater detail below. 
     With regard to the remote control functions of the remote control key  12 , the atmospheric propagation signal is received via receiving structure in the form of an antenna  32  by the control unit  30  of the vehicle. When a switch  20 - 26  is depressed by the user, a corresponding signal comprising the appropriate command and the ID code is broadcast by the transmitter  18 . The signal is received by the antenna  32 , conveyed to the control unit  30  and interrogated by the control unit  30 . The signal is interrogated for two features: whether the ID code is authentic, and whether the command is a recognized command. If the ID code is authentic and the command is recognized as one of the permissible commands, the command is implemented. However, if the ID code is not found to be authentic, the command is not implemented even if the command is recognized. Likewise, if the ID code is found to be authentic but the command is not recognized, no command is implemented. Further regarding authentication of the ID code, the inhibition of the implementation of the command can take two forms. The command can be compared to see if it is recognized, and a decision can be made to forgo implementing it when the ID code does not authenticate. On the other hand, the step of recognizing the command can be forgone if the ID code does not authenticate. 
     When the locking switch  20  or the unlocking switch  22  is depressed on the key  12 , the respective lock or unlock signal and ID code are broadcast by the transmitter  18 . The antenna  32  receives the signal, and conveys it to the controller  30  for interrogation. If the ID code of the transmitted signal matches the ID code stored at the control unit  30 , a door locking/unlocking device  34  receives the respective locking or unlocking signal from the control unit  30 . As such, the door lock/unlock device  34  drives a door locking mechanism (not shown) so as to cause the mechanism to perform the locking or unlocking operation according to the control signal. In a similar manner, when the trunk release switch is depressed and if the ID code of the transmitted signal matches the ID code stored at the control unit  30 , a trunk release device  36  receives a trunk release signal from the control unit  30  and a trunk release mechanism (not shown) to perform a releasing operation. In addition, a horn alarm device  38  and a light alarm device  40  are connected to the electronic control unit  30 . When the panic switch is depressed on the key  12 , it is because the user desires to draw attention to the vehicle. As such, if the ID code of the transmitted signal matches the ID code stored at the control unit  30 , the horn alarm device  38  sounds the vehicle&#39;s horn and the light alarm device  40  flashes the vehicle&#39;s lights on and off according to an alarm signal given by the control unit  30 . 
     Since, in accordance with the invention, the RKE functions are incorporated into the keyhead  16  of the ignition key  12  of a vehicle, it is important to prevent inadvertent RKE operations when the key  12  is being inserted into the ignition lock to start the vehicle. Thus, in accordance with the principles of the invention, the following methods of preventing inadvertent RKE operations may be provided alone, or in combination. 
     In a first embodiment, the control unit  30  is programmed to delay the execution of the RKE functions for a preset time, e.g., 200 ms, to allow for the user to insert the key and turn it to start the engine without also inadvertently operating the RKE features. The controller  30  may alternatively be programmed to ignore any received RKE functions for a similar such period of time if the key  12  is inserted into the ignition lock or, following insertion, is turned to the ignition position. The system may also be configured so that all RKE commands are always ignored for so long as the key  12  is in the ignition. In all such cases, an ignition sensor or switch  46  is used to determine the presence of the key  12  in the ignition. 
     In a further embodiment, the aforementioned delay feature is available for a preselected time (e.g. 2 seconds or less) after the driver&#39;s door has been closed. Accordingly, sensing structure in the form of a door sensor or switch  42  is provided for detecting the operation of opening and closing of the driver&#39;s door. 
     In another embodiment, a sensing structure in the form of a brake pedal sensor or switch  44  is provided. The RKE functions are cancelled by the control unit  30  if the brake pedal has been depressed. This cancellation may include a delay feature similar to that described above in conjunction with the door switch  42  and ignition switch  46  as described above. 
     In another embodiment, a sensing structure in the form of a driver&#39;s seat sensor  48  is provided. If the seat sensor  48  determines that a driver is sitting in the seat, the control unit  30  will not implement any RKE commands. The driver&#39;s seat sensor  48  may be part of an airbag system of the vehicle or may be a separate weight, infrared, or ultrasonic sensor associated with the driver&#39;s seat. 
     In yet another embodiment, a steering wheel sensor  50  is provided. The RKE functions are cancelled by the control unit  30  if movement of the vehicle&#39;s steering wheel has occurred as determined by the steering wheel sensor  50 . The steering wheel sensor  50  may be part of an anti-lock brake system or may be a separate sensor associated with a steering wheel. 
     It can be appreciated by one of ordinary skill that it may be desirable to combine two or more of these sensors and switches  42 - 50  to provide for redundant signals. For example, the RKE functions may be inhibited only when both the ignition switch  42  indicates the presence of the key  12  and when the driver seat sensor  48  indicates the driver is sitting in the seat. One of ordinary skill can further appreciate that RKE function inhibition may take the form of delaying acting upon an otherwise validly received command, temporarily ignoring such commands, or always ignoring such commands while the sensing signals are present. 
     In yet another embodiment, the control unit  30  will not execute any RKE function if the transponder  28  is communicating with the receiver  31 . It should be recalled that the transponder  28  and receiver  31  communicate for the purpose of authentication to determine whether vehicle ignition should be immobilized. This communication may only occur when the key  12  is in or near the ignition lock. As such, one may program the controller  30  to either temporarily delay, to temporarily ignore or to always ignore RKE commands whenever the transponder  28  and receiver  31  are communicating. 
     Thus, the invention provides an effective means of preventing operation of a RKE control function when a button or switch on the keyhead may be inadvertently actuated when the driver is in position to operated the vehicle. 
     The foregoing description has set forth how the objects of the present invention can be fully and effectively accomplished. The embodiments shown and described for purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments, are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the follow claims.