Abstract:
A method and a device for interrupting unintended acceleration or unintended maintenance of vehicle speed comprising providing a driver operated fuel delivery disconnect system, said fuel delivery disconnect system comprising an electronic module programmed to temporarily disconnect electrical feed to a fuel delivery mechanism. The temporary interruption of the electrical feed places the vehicle in an idle mode without disrupting other vehicle control systems.

Description:
This application claims benefit of U.S. Provisional Application No. 61/302,065 filed Feb. 5, 2010 and U.S. Provisional Application No. 61/327,632, filed Apr. 23, 2010. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to throttle control in vehicles, and more particularly to systems that prohibit unintended acceleration in vehicles. 
     2. Description of the Related Art 
     One typical system for control of a vehicle&#39;s engine throttle in modern vehicles is illustrated in  FIG. 1  and shown schematically in  FIG. 7 . An Electronic Control Module (“ECM”)  101  (referred to as “the car computer”and alternatively as “ECU”), illustrated as a microprocessor, receives electronic inputs from vehicle components such as the vehicle&#39;s transmission, cruise control, power steering, air conditioner, load (manifold absolute pressure (MAP), traction control, etc) and other remotely sent signals for processing and further component control, and may provide a voltage reference for such components. The ECM  101  also receives information indicating the position of the vehicle&#39;s accelerator pedal  114  through pedal input sensor  113 . As is typical for motor vehicles, the accelerator pedal  114  enables driver control of the vehicle&#39;s motor, from engine idle to full throttle. 
     The ECM  101  is electrically connected to an Electronic Throttle Control Motor (“ETCM”)  105  in a throttle body assembly (“TB”)  112  to provide “drive-by-wire” electronic throttle control of the vehicle&#39;s motor. The ETCM  105 , typically an electric motor, actuates a throttle plate  115  (represented by dashed lines) in the TB  112  that acts as a variable valve to control the amount of air flowing into the vehicle&#39;s motor for throttle control from idle to full throttle positions. Also connected to the ECM  101  is a throttle position sensor (“TPS”)  103  in the TB  112  to provide engine throttle plate position feedback to the ECM  101 . The TPS  103  converts physical position of the throttle plate within the TB  112  to an electrical signal for throttle feedback to the ECM  101 . The TPS  103  includes a potentiometer  108 , which provides a resistance, and wiper arm  107 . Wiper arm  107  is in communication with the throttle plate  115 . Potentiometer  108  is connected between lines  110 ,  111 , and wiper arm  108  is connected to line  109 . Line  110  is reference to ground. Lines  109 ,  110 ,  111 , are connected to ECM  101 . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principals of the invention. 
         FIG. 1  is a block diagram illustrating a prior art throttle control system for vehicles; 
         FIG. 2  is a block diagram illustrating one embodiment of an electronic failsafe device and system for degrading and disabling a vehicle&#39;s engine throttle response; 
         FIG. 3  is a top plan view illustrating, in one embodiment, the electronic failsafe device of  FIG. 2 ; 
         FIG. 4  is a schematic of one embodiment of an electronic failsafe device; 
         FIG. 5  is a flow diagram of, in one embodiment, stages/requirements to activate the failsafe device; 
         FIGS. 6A-6F  is a schematic showing subcomponents of another embodiment of an electronic failsafe device; 
         FIG. 7  is a diagram illustrating a throttle body and brake in a prior art configuration with a vehicle&#39;s ECM; 
         FIG. 8  is a diagram illustrating one embodiment of a system having a throttle body in communication with a car computer through a failsafe device; 
         FIG. 9  is a top plan view of a printed circuit board (“PCB”) for the failsafe device illustrated in  FIGS. 6A-6F . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An electronic failsafe device is disclosed for use in a system capable of degrading and disabling a vehicle engine&#39;s throttle response in a safe manner. The device is particularly useful to rapidly lower the RPM of an out-of-control high-revving engine to a safe and manageable idle speed. 
       FIG. 2  illustrates one embodiment of an electronic fail safe system  300  that includes and electronic failsafe device  200  that is designed to prohibit unintended acceleration by, preferably, opening the negative side of the ETCM  105  electrical circuit. Under normal operating conditions, the TPS  103  sends a non-zero signal voltage to the ECM  101 , typically varying in voltage from 0.5 vdc at idle (Idle) to 4.80 vdc at wide open throttle (WOT). As mentioned, above, the function of the TPS  103  is to mirror the position of the throttle plate within TB  112  and to transmit this information to ECM  101 . Preferably, TPS  103  is a potentiometer and, with few exceptions, works on a 0-5 volt dc scale. As an example, at idle TPS  103  voltage will typically show 0.5 vdc and, depressing accelerator pedal  114 , will smoothly and incrementally increase the voltage until reaching Wide Open Throttle (WOT). At WOT TPS  103  will typically send 4.8 vdc to ECM  101 . Therefore, 50% of WOT will show approx. 2.0 vdc. When the failsafe device  200  receives greater than a threshold activation voltage, preferably 2.0 vdc or greater signal via TPS  103 , this action will satisfy the first of two stages/requirements in order to activate the failsafe device to prohibit unintended acceleration. The second stage/requirement is preferably satisfied if the operator depresses the vehicle brake pedal  302  shown schematically in  FIG. 8 , causing the brake pedal switch  104  to contact to chassis ground to activate the failsafe device  200 . If both stages/requirements are not detected by the failsafe device  200 , the device  200  will not activate to interrupt the ETCM  105  electrical circuit, preferably by opening the negative side of the ETCM  105  electrical circuit. Or, the failsafe device  200  may be connected to open the positive side of the ETCM  105  electrical circuit. Thereby, with a TPS  103  signal of less than preferably 2.0 vdc the operator will be allowed to depress the brake pedal as normal without activation of the failsafe device  200 . Likewise, with brake pedal switch  104  circuit open (brake pedal not depressed) the operator will be allowed to accelerate up to full throttle as normal without activation of the failsafe device  100 . It is only when the 2.0 vdc or greater signal via TPS  103  AND brake pedal  104  is depressed that the failsafe device  200  is activated to open the negative side of the ETCM  105  resulting in the throttle body returning to drive the motor to an idle state. Failsafe device  200  through the use and implementation of an electrical switch, opens the negative side of ETCM  105  electrical circuit only when both stages/requirements are met. 
     The failsafe device  200  can be powered by a number of different sources, either singly or in combination to ensure uninterrupted power during an unintended acceleration event.
         Direct Connect Power Supply: This method of supplying power to the failsafe device would require a direct line from the main 12V battery found in the vehicle to the failsafe device.   Secure Power Source: The failsafe device can also be supplied with a completely isolated power source not tied to the vehicle power system. This would include a rechargeable battery pack located under the dash of the vehicle supplying an uninterruptible power source to the failsafe device. This solution would isolate the failsafe device from all unknown power spikes or power loses during and unintended acceleration event.       

     The driver, by pressing the brake, allows the failsafe device to be powered to monitor for events. Possible events include monitoring the throttle position for a sensed level above a specified threshold through monitoring of the TPS signal or for a level outside of specified ranges. In alternative embodiments that do not depend on the TPS signal, the failsafe device may also respond to external signals such as a momentary switch in the cabin, the vehicle&#39;s hazard button in the cabin, a master cylinder pressure switch or a remote/satellite signal, MAP (manifold absolute pressure), engine RPM, vehicle speed, alternator (and other engine driven accessories) RPM sensor(s), crank and camshaft speed sensors, transmission torque converter speed sensor, air speed sensor (aviation use) or any other direct RPM/speed sensor data. 
     A timer function  202  in the failsafe device  200  maintains the negative side of ETCM  105  electrical circuit open for a predetermined delay, preferably 3-5 seconds (this duration is adjustable), and then preferably automatically deactivates (resets) and allows for standard vehicle functions after that time period. The 3-5 second “time-out” function stops any harsh/violent accelerations and decelerations (aka “bucking”) in the event the problem persists. The failsafe device  200  will give the operator immediate control when confronted with unintended acceleration under many conditions (i.e. floor mat, transient electrical glitch, length of brake pedal, obstacle obstruction on accelerator pedal, component or components failure, voltage spike, human error, etc.) The emergency flashers deploy through flasher relay module  206  and reset automatically by timer function with the activation of the failsafe device  200 . 
       FIG. 3  illustrates an overhead view of one implementation of the failsafe device  200  first illustrated in  FIG. 2 . Terminals  1 - 6  are provided for coupling to external components, with terminal reference numbers corresponding to the terminal reference number illustrated in  FIG. 2 . 
       FIG. 4  is a schematic of one embodiment of an electronic failsafe device. 
       FIG. 5  is a flow diagram illustrating one embodiment of a method of using the failsafe device. A TPS output voltage is received by the failsafe device. If the TPS output voltage is greater than a threshold activation voltage, preferably greater than 1.4 vdc, and the failsafe device senses the brake pedal switch switched to ground, the failsafe device is activated. 
       FIG. 6 , shown as 6 subcomponents  6 A,  6 B,  6 C,  6 D,  6 E, and  6 F, is a schematic of another embodiment of the failsafe device comprising  6  subcompounds  6 A-  6 F that uses the vehicle&#39;s braking indicator (received at braking terminal) to power the failsafe device. Inherently, such an embodiment satisfies one of the two conditions necessary to activate the failsafe device described by  FIG. 2  (i.e. application of the vehicle&#39;s brake). In  FIG. 6 , the label “SENSOR” is made in reference to the ETCM of  FIG. 2 . When a brake signal is active, a 12V supply is provided to module U 1  through relaypower terminal via R 3 , with U 1  converting the 12V to 5V for VCC. The relaypower terminal is provided by the braking indicator through R 2  and D 1 , and it also charges storage capacitors C 2 , C 3 , C 4 , C 5 , C 7  and C 9  which provide filtering for the 12V and VCC signal. VCC supplies power to microprocessor U 2  and supporting circuitry of the failsafe device such as signal conditioning D 2 , D 6  and D 7 , and power-on reset (D 5 , R 6 , C 6 ) for the module U 2 . TPS signals are monitored through terminals TPS  0  and TPS  1  for an event that requires deceleration, such as receipt at TPS 0  of a voltage greater than approximately 1.4 vdc. Or, terminal TPS 1  may also be in communication with potentiometer  108  of  FIG. 2  in an inverted voltage relationship to TPS 0  to enable redundancy checking of the TPS signal. For example, if TPS 0  represents a potentiometer throttle position of 10%, then the signal at TPS 1  would represent a throttle position of 90% in a normal operating condition. If the correlation is detected to be out of specification, the “second condition” is satisfied and the failsafe device would be activated. 
     Once the second condition is satisfied, the failsafe device switches Q 1  on via R 4  to activate the relay K 1 , preferably using a pulse width modulation (“PWM”) switching scheme based on elapsed time (“Programmable Modulated Throttle control technology”) to ensure that the TPS signal does not trigger in the ECM a vehicle “limp mode.” Or, such PWM switching of the relay K 1  may be based on amplitude of the detected TPS signal, such as “switch off” in response to receipt of a TPS signal passing approximately 0.5 vdc and “switch on” if such signal again exceeds approximately 1.4 vdc (“Adaptive Firmware Throttle Control”). In other embodiments, suitable voltages may be used that correspond to the applicable vehicle of interest. Preferably, both switching modes may be realized in the failsafe device. 
     The Adaptive Firmware Throttle Control is software loaded onto the processor U 2  to automatically adjust timing for periodic interrupt of the duty cycle of the ETMC circuit help the driver regain control of the vehicle. The Programmable Modulated Throttle Control is a set of values, such as timing for the periodic interrupt of the ETCM circuit that are pre-programmed into the module U 2 . 
     Both the hardware and software of the failsafe device when activated will provide filtering of the TPS signals to reduce false triggering, such as through R 1 /C 1 , R 8 /C 10 , R 5 /R 7 /C 8  and software detection in module U 2 . This condition is done to prevent false triggering of the failsafe device adding additional safety conditions for the driver. 
     The failsafe device will also be equipped with an event logging system implemented in the module U 2 . This logging system will detect when an event takes place and log that date and time into a memory device. All relevant information (power supply voltage, TPS signals, time reference data, and location) will be stored into the memory device. 
     The device will have a dual color LED (not shown) to facilitate initial installation. For example, once the device is installed and powered, the failsafe device may look for signals indicating a normal operating condition and provide visual feedback to the installer through the dual color LED. 
     Programming capability for the module U 2  is provided through connector J 1  that allows the software to be loaded into the failsafe device. 
       FIG. 7  is a block diagram illustrating a prior art system  100  including a throttle body  112  and brake pedal  302  in a configuration with a vehicle&#39;s ECM such as shown in  FIG. 1 . 
       FIG. 8  is a diagram illustrating an embodiment of a system  300  having a throttle body  112  in communication with an ECM  101  (a car computer) through a failsafe device  200  such as shown in  FIG. 2   
       FIG. 9  is a top plan view of a printed circuit board (“PCB”)  400  for the failsafe device  200  illustrated in  FIGS. 6A-6F . 
     While various implementations of the application have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. For example, the fail safe system described herein is not limited to a throttle system. It is contemplated that the control systems described herein can be used on other fuel delivery systems including, but not limited to variable speed fuel pumps and the like. All references herein to an ETCM can be replaced by a more general reference to an electronic fuel delivery control module (EFCM). In such an instance a fuel feed rate sensor (FFRS) replaces the throttle position sensor (TPS). Based on the teachings herein, one skilled in the art can readily understand and implement the disclosed fail safe system on any vehicle having a fuel delivery and quantity control system.