Abstract:
A vehicle anti-theft system is configured to apply indications of driver presence and absence to control of a circuit between a brake pedal switch and a park shift interlock and/or a vehicle brake. Vehicle drivability is impaired without an indication of driver presence. The driver absence indication can include the combination open driver&#39;s door and an empty driver&#39;s seat. The driver presence indication can include authorized driver identification through entry of a code or other authorization mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/026,265, filed on Jul. 18, 2014, the contents of which application are herein incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a vehicle anti-theft system, and more particularly, to automatically impair vehicle drivability based on vehicle status. 
     BACKGROUND OF THE INVENTION 
     Vehicle theft often occurs when vehicles are left running and unattended. Locking or securing an unattended vehicle is not always possible in emergency situations, often due to the need to power vehicle lighting, on board computers, video and audio devices, and other vehicle features that record the events surrounding the emergency scene. For example, ambulances often have climate control devices needed to control the temperature of medications, as well as powered medical devices that must remain charged and ready for use instantly. In addition, these vehicles are also frequently exited by emergency response personnel very rapidly, making it more likely to overlook necessary steps to secure the vehicle. 
     As a theft prevention mechanism, it has previously been contemplated to automatically deploy the parking brake in emergency vehicles equipped with air brakes. Such methods are described in, for example, U.S. patent application Ser. No. 14/101,068, which are incorporated by reference herein in its entirety. This approach is also advantageous in that it can be readily retrofit into existing vehicles. However, the same approach is less readily adapted to vehicles without air brakes, where manual mechanical power must be applied to engage the parking brake. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an object of the present invention to provide an improved anti-theft system for motor vehicles, and in particular, a system that will be effective to deter theft of emergency vehicles left unattended with the engine running. According to an embodiment of the present invention, a vehicle anti-theft system is designed to monitor the vehicle driver&#39;s presence to allow for a running and unattended vehicle to be automatically rendered undriveable when the vehicle driver is absent. The vehicle anti-theft system includes at least one sensor to indicate a vehicle driver&#39;s presence, an electronic control unit (ECU) configured to control vehicle drivability based on the driver&#39;s presence, and an input device connected to the ECU for receiving an authorization for vehicle drivability. The authorization enables the vehicle to be drivable, when the driver presence is detected. 
     In one aspect, the ECU impairs vehicle drivability by interrupting the connection between the brake pedal and the park shift interlock of the vehicle to impair vehicle drivability, when the driver&#39;s absence is detected. The ECU enables vehicle drivability by maintaining the connection, when the vehicle driver&#39;s presence is detected and an authorization signal is received from the input device. 
     In another aspect, the ECU applies at least one brake of a vehicle to impair vehicle drivability when the driver&#39;s absence is detected. The ECU releases the at least one brake of the vehicle to enable vehicle drivability, when the driver&#39;s presence is detected and an authorization signal is received from the input device. 
     In another aspect, the input device is configured to indicate one or more of driver&#39;s seat occupancy, door position and parking brake status of the vehicle by a light pattern, a light color and/or a sound pattern and a sound pitch. 
     According to a further aspect, the system includes a manual override mechanism to control drivability of the vehicle via directly controlling circuit between the brake pedal and the park shift interlock of the vehicle and/or at least one vehicle brake without the operation of the ECU. 
     According to an additional aspect, the one or more sensors to detect the driver&#39;s presence includes a driver door position sensor in communication with the ECU configured to indicate the position of the driver door (open or closed), and a driver seat sensor in communication with the ECU configured to indicate the status of the driver seat (occupied or empty). The indication of driver absence requires both the driver door in the open position and the driver seat unoccupied for a predefined amount of time. 
     According to a method aspect, a method of operating the vehicle anti-theft system includes detecting the vehicle driver&#39;s presence. When the driver&#39;s absence is detected, interrupting a connection between the brake pedal and the park shift interlock of the vehicle via an ECU, disabling vehicle drivability. When the driver&#39;s presence is detected and an authorization signal is received, the connection between the brake pedal and the park shift interlock of the vehicle is established, enabling vehicle drivability. 
     According to another method aspect, a method of operating the vehicle anti-theft system includes detecting the vehicle driver&#39;s presence. When the driver&#39;s absence is detected, at least one brake of the vehicle is applied via the ECU, impairing vehicle drivability. When the driver&#39;s presence is detected and an authorization signal is received, the at least one brake of the vehicle is released via the ECU, enabling vehicle drivability. 
     These and other objects, aspects and advantages of the present invention will be better appreciated in view of the drawings and their accompanying description. It will be understood, however, that that the present invention is not necessarily limited thereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic operational view of components of an vehicle anti-theft system according to the present invention; 
         FIG. 2  is a detailed schematic operational view of components of a vehicle anti-theft system according to the present invention; 
         FIG. 3  is another detailed schematic operational view of components of a vehicle anti-theft system according to the present invention; 
         FIG. 4  is a flowchart illustrating an example vehicle anti-theft method; and 
         FIG. 5  is a flowchart illustrating another example vehicle anti-theft method. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , the vehicle anti-theft system  10  includes an ECU  20  configured to receive input signals from at least one sensor and generate control outputs based thereon. For example, the at least one sensor includes the driver seat sensor  12  and the driver door position sensor  14  to indicate the driver&#39;s presence or absence. The at least one sensor can also include a brake pedal position sensor  16  and a manual brake position sensor  18 . The ECU  20  is configured to impair vehicle drivability when a signal indicative of driver absence is received from the at least one sensor. The vehicle anti-theft system  10  also includes an input device  22  connected to the ECU  20  to receive an authorization signal (e.g., a correct code) to enable vehicle drivability. The ECU  20  is configured to enable vehicle drivability when a signal indicative of the driver&#39;s presence is received from the at least one sensor and an authorization signal is received from the input device  22 . The input device  22  is also configured to indicate driver&#39;s seat occupancy, door position, and parking brake status by a light pattern, a light color, sound pattern and/or sound pitch. 
     In one embodiment, the ECU  20  impairs the vehicle drivability by interrupting the circuit  24  between the brake pedal and the park shift interlock of the vehicle. The ECU  20  enables vehicle drivability by maintaining the circuit connection between the brake pedal and the park shift interlock of the vehicle. For example, one or more relays and/or switches can be used to maintain or break the circuit  24  between the brake pedal switch and the park shift interlock, rendering the vehicle drivable or undrivable. 
     In another embodiment, the ECU  20  disables vehicle drivability by applying at least one service brake of the vehicle and enables vehicle drivability by releasing the at least one service brake. For example, a force can be released or applied to a service brake such as a front wheel brake, a rear wheel brake, manual brake and/or a valve connected to the service brake, rendering the vehicle drivable or undrivable. 
     As used herein, ‘electronic control unit’, or ECU, refers generically to a hardware device having at least one processor and memory media. The ECU can be configured to receive input signals, process said signals based upon instructions/data stored in memory, and generate (or not generate) appropriate output signals. 
     The input device  22  could include a keypad, a biometric scanner, a radio frequency identification (RFID) reader, wireless receiver or similar mechanism for receiving an authorization input. Varying sensor types could be used for the sensors  12 ,  14 ,  16  and  18 , such as contact sensors, proximity sensors, pressure switches, position sensor, etc. The ECU  20  can also drive audio and/or visual indicators, such as lights, buzzers, displays, and the like. For example, the input device  22  can include one or more lights (e.g., LED lights) and/or speakers to indicate one or more of driver&#39;s seat occupancy, door position and parking brake status by light pattern, sound pattern, light color and/or sound pitch. For example, when the driver&#39;s seat is empty, the one or more lights on the input device  22  can flash certain colors (e.g., red) fast and/or the speakers can generate a high-pitched sound. When the driver door is open, the one or more lights can flash certain colors (e.g., red) slowly and/or the speakers can generate a low-pitched sound. The one or more lights can remain a certain color (e.g., green) when the anti-theft system  10  has self checked all components and circuits. 
     Modern vehicles having automatic transmission are equipped with a park shift interlock that require the brake pedal to be depressed before the shifter lever can be moved from park to the intended gear selection. These vehicles also have a hand/foot brake system used to slow the vehicle if the hydraulic braking system fails. It is recommended to be used when the vehicle is parked to ensure the vehicle does not move. These features are relevant to whether a vehicle has a drivability. 
     In an exemplary implementation, when the driver is ready for the vehicle to be mobile again, shifting a gear selector from park to an intended gear position alone will not enable the vehicle to be mobile. The driver must also enter a predetermined authorization signal (e.g., a code) via the input device  22  (e.g., a fixed keypad), sending a signal to the ECU  20  to close the circuit between the brake pedal and the park shift interlock and/or release the force applied to a brake system. The authorization signal (e.g., a code) controls the ECU  20  and thus enables the vehicle gear selector to be moved from park to an intended gear. 
     The anti-theft operation can be triggered by the ECU  20  only when the vehicle driver door is open and the seat is unoccupied for a specified period of time (e.g., 20 seconds). A driver could leave the seat on going over a bump or leaning over in the vehicle to perform a task, but this alone will not trigger the anti-theft operation. The driver could open the driver door for various reasons, but this alone will not trigger the anti-theft operation. A separate timer can be applied to trigger the operation of ECU  20  after the driver&#39;s seat is unoccupied for a specified period of time. 
     Combining driver door position sensor  14  and seat sensor  12  advantageously indicates driver absence. If the ECU  20  receives signals indicating that the driver&#39;s seat is unoccupied and the driver&#39;s door is open, then the ECU  20  will act so as to apply automatically at least one brake of the vehicle and/or disconnect the circuit between the brake pedal switch and the park shift interlock. Requiring two independent absence indications will greatly reduce the risk of a potentially applying an anti-theft operation when a driver is present. A predetermined duration (e.g., 20 seconds) can be set for receipt of both absence indicator signals to further reduce the likelihood applying an anti-theft operation when it is not needed. 
     The vehicle anti-theft system  10  further comprises a manual override system  26 . The manual override system  26  can bypass the ECU  20  and transmit control signals directly from a user to one or more brake systems and/or the electronic circuit between the brake pedal switch and the park shift interlock. For example, the manual override system  26  can operate directly on a coupling element connected to a parking brake, or arranged in a circuit effectively bypassing the coupling element to control a parking brake. 
     Although operating along generally similar principles, there are many variations in the exact components and configurations in the anti-theft system depicted in  FIG. 1 . Accordingly, components of the anti-theft system  10  are depicted schematically, and it will be appreciated that the present invention can be advantageously integrated into a wide variety of anti-theft system  10  implementations. 
       FIG. 2  a detailed schematic operational view of components of a vehicle anti-theft system according to the present invention. A 12V DC battery  30  is configured to provide power to the ECU  20  via A cable. The ECU  20  is configured to determine driver presence or absence by receiving input signals from the driver seat sensor  12  via E cable, and receiving input signals from the driver door position sensor  14  via D cable. C cable is connected to a pressure switch applying pressure on park canisters. When a user enters a correct code via the input device (e.g., keypad)  22  via F cable, the relay or switch in the circuit  24  between the brake pedal and the park shift is closed, enabling the shifter lever to be moved from park to the intended gear selection. As an example, the seat sensor  12  is configured to transmit a signal via E cable to the ECU  20  when a certain amount of weight (e.g., more than 50 lbs) is detected for a predefined amount of time (e.g., 20 seconds). As another example, the door position sensor (e.g., switch)  14  is configured to transmit a signal to the ECU  20  via D cable by closing a door position circuit. The input device  22  is a keypad for inputting one or more authorization codes. The key override system  26  is configured to directly control (e.g., close or interrupt) a brake circuit. For example, the key override system  26  can operate directly on a coupling element connected to a parking brake, or arranged in a circuit effectively bypassing the coupling element to control a parking brake via B cable. 
     When the driver seat is occupied, vehicle door is closed, and a parking brake applied (pressure applied on a parking brake and parking brake knob is down), LEDs on the input device  22  (e.g., keypad) is configured to be steady green. When the driver seat is occupied, vehicle door is closed, and a park brake released (no pressure applied on a parking brake and a parking brake knob is up), LEDs on the input device  22  (e.g., keypad) is configured to be steady red. 
     When the vehicle door is open, the input device  22  is configured to flash fast red regardless the status of a parking brake and/or occupancy of driver seat. When the driver seat is empty, the input device  22  is configured to flash slow red regardless of the status of a parking brake and/or position of a vehicle door. 
       FIG. 3  is another detailed schematic operational view of components of a vehicle anti-theft system according to the present invention. The ECU  20  is configured to monitor C cable connected to a pressure switch  28  to indicate parking brake status, D cable connected to a door switch  14  to indicate door position, and E cable connected to a seat sensor  12  to indicate a seat occupancy status. 
     In one embodiment, C cable is connected to a pressure switch  28 , when the pressure switch  28  is closed, air pressure is released from the parking brake canisters and the park brake knob is up. When the pressure switch  28  is open, air pressure is applied on the parking brake canisters and the park brake knob is down. D cable is connected to a door sensor  14  (e.g., switch), wherein a door position circuit is open when vehicle door is closed, and closes the door switch circuit when vehicle door is open. E cable is connected to a seat sensor  12 , wherein the seat sensor circuit is open when driver seat is empty and seat sensor is closed when driver seat is occupied. 
     In one embodiment, when the driver seat is occupied, vehicle door is closed, and a park brake applied (with pressure applied and knob up), the LED on the input device  22  (e.g., keypad) indicates steady red. When the driver seat is occupied, vehicle door is closed, and a park brake released (no pressure applied and knob down), the LED on the input device  22  (e.g., keypad) indicates steady green. 
     When the vehicle door is open, the input device  22  is configured to flashes fast red regardless the status of C cable (e.g., whether a parking brake is applied) or status of E cable (e.g., whether driver seat is occupied). When the driver seat is empty, the input device  22  is configured to flash slow red regardless of the status of C cable (e.g., whether a parking brake is applied) or status of D cable (e.g., whether vehicle door is closed). 
     When the driver seat becomes unoccupied and driver&#39;s door is open, if the C cable indicates brake is released and the knob down, the ECU  20  transmits a signal to an audible speaker in the input device  22  for an alert tone for a predefined period of time (e.g., 2 seconds). If the parking brake is not set during the predefined period of time (e.g., 2 seconds), the ECU  20  sends a signal to B cable (parking brake set solenoid) to set the parking brake. 
     When the input device  22  is steady green, if both the driver seat becomes empty (slow red flash) and driver&#39;s door is opened (fast flash), ECU  20  closes the pressure switch  28 , thus applying pressure on park canisters and locking the vehicle in parking position. 
     If the input device  22  shows steady red or flashing red instead of steady green when the driver&#39;s door is closed and the driver seat is occupied, then the anti-theft system needs service. The system self-checking can provide feedback to driver via color and color pattern of the input device  22 . 
       FIG. 4  is a flowchart illustrating an example vehicle anti-theft method  400 . 
     At step  401 , the driver&#39;s status (absence or presence) is detected. As an example, the driver&#39;s status is detected via the driver door position sensor  14  and seat sensor  12 . If the seat sensor  12  indicates the driver seat is unoccupied and the position sensor  14  indicates the driver&#39;s door is open, the driver absence is detected. If the seat sensor  12  indicates the driver seat is occupied and the position sensor  14  indicates the driver door is closed, the driver presence is detected. 
     At step  402 , a connection between the brake pedal and the park shift interlock of the vehicle is interrupted via an ECU to impair vehicle drivability when the driver absence is detected. 
     At step  403 , a connection between the brake pedal and the park shift interlock of the vehicle is established to enable vehicle drivability via the ECU when the driver presence is detected and an authorization (e.g., authorization code) is received. 
       FIG. 5  is a flowchart illustrating another example vehicle anti-theft method  500 . 
     At step  501 , the driver&#39;s status (presence or absence) is detected. As an example, the driver status is detected via the driver door position sensor  14  and seat sensor  12 . If the seat sensor  12  indicates the driver seat is unoccupied and the position sensor  14  indicates the driver door is open, the driver absence is detected. If the seat sensor  12  indicates the driver seat is occupied and the position sensor  14  indicates the driver door is closed, the driver presence is detected. 
     At step  502 , when the driver absence is detected, at least one brake of the vehicle is applied via an ECU to impair vehicle drivability. The brake can be applied and released via a coupling element connected to a brake or arranged in an electronic circuit, effectively bypassing the coupling element to control a brake. The input device connected to the system can indicate driver&#39;s seat occupancy, door position and parking brake status by a light pattern, sound pattern, and a light color (e.g., slow flash red, fast flash red and/or a certain sound pitch). 
     At step  503 , when the driver presence is detected and an authorization signal is received, the at least one brake of the vehicle is released, enabling vehicle drivability. The brake can be applied and released via a coupling element connected to a brake or arranged in an electronic circuit, effectively bypassing the coupling element to control a brake. The input device connected to the system can indicate driver&#39;s seat occupancy, door position and parking brake status by a light pattern, sound pattern, and a light color (e.g., steady green and/or a certain sound pitch). 
     From the foregoing, it will be appreciated that the present invention augments addresses both safety problems and theft issues endemic to many modern emergency vehicles. In general, the foregoing description is provided for exemplary and illustrative purposes; the present invention is not necessarily limited thereto. Rather, those skilled in the art will appreciate that additional modifications, as well as adaptations for particular circumstances, will fall within the scope of the invention as herein shown and described and the claims appended hereto.