Abstract:
A launch control system and method for vehicles equipped with manual transmissions includes a throttle position sensor, a clutch position sensor, a vehicle speed sensor, a system activation switch and a control which receives data from the sensors and controls braking of the non-driven wheels. The control module contains a control algorithm which interrogates the system activation switch, interrogates the clutch position sensor, determines the vehicle speed, interrogates the throttle position sensor and under certain conditions applies the brakes to the non-driving wheels through the vehicle ABS system when the throttle is depressed beyond a predetermined threshold and until the clutch is released beyond a predetermined threshold.

Description:
FIELD 
     The present disclosure relates to ancillary control systems for vehicles equipped with manual transmissions and more particularly to a launch control system for a vehicle equipped with a manual transmission. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     A frequently encountered challenge of operating a vehicle having a manual transmission is accelerating from a stop on an incline. With only two feet and three pedals, commencing smooth acceleration without stalling the engine, rolling into the vehicle directly behind or lurching forward requires a certain expertise. A similar, though generally less dramatic problem involves parallel parking on a hill. Here, since both forward and rearward motion may be required, albeit at slower speeds, the operator must also take into account the difference between the gear ratios of first gear and reverse gear as he or she attempts to parallel park the vehicle, ideally without accomplishing same by contact. 
     The foot versus pedal ratio (2:3) also presents problems in competitive driving situations. While drag strips and launch sites on race tracks tend to be level, any undesired forward or backward motion of the vehicle is problematic. Forward motion may cause the vehicle to roll through the timing beams prematurely which may result in disqualification whereas backward motion will significantly and adversely affect the launch as not only must the vehicle be accelerated but its direction must also be reversed prior to such acceleration. 
     Accordingly, there is a need for a vehicle equipped with a manual transmission to have the capability, under active, operator control, to remain stationary, in either a level, uphill or downhill orientation, prior to operator initiated motion. The present invention is so directed. 
     SUMMARY 
     The present invention provides a launch control system for vehicles equipped with manual transmissions. The system includes a throttle position sensor, a clutch position sensor, a brake activation sensor, a vehicle speed sensor, a system activation switch and a control module which may either be a transmission control module (TCM) or a traction control system (TCS) module which receives data from the sensors and controls braking of the non-driven wheels. The control module contains a control algorithm which interrogates the system activation switch, interrogates the clutch position sensor, determines the vehicle speed, interrogates the throttle position sensor and under certain conditions applies the brakes to the non-driving wheels through the vehicle ABS system when the throttle is depressed beyond a predetermined threshold and until the clutch is released beyond a predetermined threshold. 
     Thus it is an aspect of the present invention to provide a launch control system for a vehicle having a manual transmission. 
     Ii is a further aspect of the present invention to provide a launch control algorithm for a vehicle having a manual transmission. 
     It is a still further aspect of the present invention to provide a launch control system for a vehicle having a manual transmission including a throttle position sensor, a clutch position sensor, a brake activation sensor and a vehicle speed sensor. 
     It is a still further aspect of the present invention to provide a launch control system for a vehicle having a manual transmission including a throttle position sensor, a clutch position sensor, a brake activation sensor, a vehicle speed sensor, a system activation switch and a transmission control module. 
     It is a still further aspect of the present invention to provide a launch control algorithm for a vehicle having a manual transmission which interrogates a system activation switch, interrogates a clutch position sensor, determines a vehicle speed and interrogates a throttle position sensor. 
     It is a still further aspect of the present invention to provide a launch control algorithm for a vehicle having a manual transmission which interrogates a system activation switch, interrogates a clutch position sensor, determines a vehicle speed and interrogates a throttle position sensor and applies the brakes to the non-driving wheels through the vehicle ABS system until the throttle is depressed beyond a predetermined threshold and the clutch is released beyond a predetermined threshold. 
     Further aspects, advantages and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a schematic view of a motor vehicle equipped with a launch control system according to the present invention; and 
         FIG. 2  is an algorithm or subroutine contained within a control module according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     With reference now to  FIG. 1 , a motor vehicle incorporating the present invention is schematically illustrated and generally designated by the reference number  10 . The motor vehicle  10  includes a prime mover  12  such as a gasoline, Diesel, flex-fuel or hybrid power plant having an output which drives a manual clutch  14  which is under direct operator control. The manual clutch  14 , in turn, drives a manual transmission  18  which is also under direct operator control. The output of the manual transmission  18  is coupled to and drives a final drive assembly  20  which may include, for example, a propeller shaft  22 , a differential  24 , rear axles  26  and rear tire and wheel assemblies  28 . 
     The motor vehicle  10  also includes front tire and wheel assembles  32  associated with steering components (not illustrated) and a throttle or accelerator pedal  34  which may be either directly connected to or electrically or electronically coupled to a fuel metering or energy controlling component  36  on the prime mover  12 . The throttle or accelerator pedal  34  includes a full range, i.e., proportional or analog, position sensor  38  which provides an output indicating the current position of the throttle or accelerator pedal  34  to a transmission control module (TCM) or a traction control system (TCS) module  40 . It should be appreciated that either of these devices, as well as other electronic vehicle control modules or a dedicated control module, which both generally include inputs which receive data from powertrain sensors throughout the vehicle, are suitable locations for receiving, processing and outputting signals associated with the algorithm or subroutine of the present invention. 
     The motor vehicle  10  also includes a clutch pedal  42  which is linked either mechanically through a cable or through a hydraulic line which are both identified by reference number  44  to the manual clutch  14 . The clutch pedal likewise includes a full range, i.e., proportional or analog, position sensor  46  which provides an output indicating the current position of the clutch pedal  42  to the control module  40 . 
     With regard to the two position sensors, the throttle position sensor  38  and the clutch position sensor  46 , it should be understood that full proportional or analog sensors provide real time data to the control module  40  of the current, exact position of the pedals  34  and  42 . Thus, even though only two positions of the clutch pedal  42  (an intermediate threshold and fully depressed) and one position (an intermediate threshold) are significant with regard to operation of the algorithm or subroutine  100  described below, suggesting that a three state and a two state sensor, respectively, could be utilized, the utilization of proportional or analog sensors  38  and  46  allows ready and straightforward adjustment and resetting of the thresholds electronically within the control module  40  to adapt the system to various vehicles, powertrains, engineering criteria, design requirements and performance goals. 
     The motor vehicle  10  also includes an anti-lock braking system (ABS)  50 . The anti-lock braking system  50  includes two front wheel speed sensors  52  and two rear wheel speed sensors  54  which provide information in real time regarding the speed of each front and rear tire and wheel assembly  32  and  28  to an ABS control module  56 . The ABS control module  56  is connected to a vehicle brake pedal  62 . The ABS control module  56  includes four output hydraulic lines  64 , two of which are illustrated in  FIG. 1 , which individually provide pressurized brake fluid to each brake assembly  66  associated with each tire and wheel assembly  28  and  32 . With regard to the present invention, those hydraulic lines  64  associated with the front, non-driven wheels  32  relate to and enable the invention in the rear wheel drive motor vehicle  10  illustrated. If the vehicle were a front wheel drive vehicle, the hydraulic lines involved with and enabling the invention would be those two lines  64  associated with the rear, non-driven wheels  28 . 
     Finally, the vehicle includes a two position, operator selectable switch  70  which selects either a normal driving mode “N” in which the system of the present invention is disabled and the vehicle and its powertrain operates normally or a competitive or launch mode “C” in which the vehicle powertrain operates, inter alia, according to the algorithm or subroutine  100  presented in  FIG. 2 . The output of the operator selectable switch  70  is provided to the control module  40 . 
     Referring now to  FIGS. 1 and 2 , the algorithm or subroutine which provides launch control for the manual transmission motor vehicle  10  is illustrated and generally designated by the reference number  100 . The algorithm or subroutine  100  may be stored in, for example, a microprocessor contained within the control module  40 . The algorithm or subroutine  100  begins with an initializing step  102  which resets and clears all registers and then proceeds to a data acquisition step  104  which interrogates or reads the operator selectable switch  70  to determine whether it is set to “N” for normal operation or “C” for competitive driving and launch control. In the decision point  106 , if the switch  70  is set to “N,” the algorithm or subroutine  100  exits the decision point  106  at NO, terminates at a first endpoint  108  and the manual transmission  18  and associated systems operate in a normal mode. 
     If the switch  70  is set to “C,” the decision point  106  is exited at YES and the clutch pedal position sensor  46  is interrogated or read in a data acquisition step  112  to determine if the clutch pedal  42  is fully depressed (such that the clutch  14  is full disengaged). In a decision point  114 , if the clutch pedal  42 , as sensed by the clutch pedal position sensor  46 , is not fully depressed, the decision point  114  is exited at NO and the algorithm  100  returns to the initializing step  102 . If the clutch pedal  42  is fully depressed, the decision point is exited at YES and the algorithm  100  moves to another data acquisition step  116  which interrogates or reads a vehicle speed sensor such as one or more of the wheel speed sensors  52  and  54  associated with the anti-lock brake system  50  to determine if the motor vehicle  10  is stationary. Typically, all four of the wheel speed sensors  52  and  54  are interrogated and if any one indicates motion of the motor vehicle  10 , the algorithm  100  utilizes this information in the following step. 
     Given the data from the step  116 , a decision point  118  is exited at NO if the motor vehicle  10  is not stationary, that is, the motor vehicle  10  is moving, and the algorithm or subroutine returns to the initializing step  102 . If the vehicle  10  is stationary, the decision point  118  is exited at YES and a data acquisition step  122  is entered which interrogates or reads the accelerator pedal position sensor  38  to determine the current position of the accelerator pedal  34 . A decision point  124  is then entered and if the current position of the accelerator pedal  34  is not depressed beyond a predetermined threshold or position, the decision point  124  is exited at NO and the algorithm returns to the initializing step  102 . If the accelerator pedal  34  is depressed beyond the predetermined threshold or position, the decision point  124  is exited at YES and an action or execution step  126  is entered which applies the brakes by pressurizing the two hydraulic lines  64  to the front, non-driving wheels  32 . It should be appreciated that the action step  126  is undertaken and accomplished through data sharing and integration of the control module  40  with the anti-lock braking system  50 . Additionally, it should be understood that if the motor vehicle  10  is a front wheel drive vehicle, as noted above, the non-driving wheels will be at the rear of the vehicle and it is the brakes of these two (rear) wheels  28  that will be applied. 
     Next, the algorithm or subroutine  100  moves to another data acquisition step  132  which again interrogates the clutch pedal position sensor  46 . Now, if the clutch pedal  44  is (still) depressed beyond a predetermined threshold which substantially coincides with the point of incipient clutch engagement, a decision point  134  is exited at YES and the algorithm  100  returns to the data acquisition step  122  which again interrogates the accelerator position sensor  38 . If the manual clutch pedal  44  is not depressed beyond the predetermined threshold, which generally indicates incipient vehicle launch, the decision point  134  is exited at NO and the algorithm  100  moves to an action or execution step  138  which releases the front, non-driving wheel brakes  66  set previously in action step  126 . At this point, the motor vehicle  10  may launch under the algorithm  100  without pre-launch forward or backward motion and the algorithm  100  terminates at a second end point  140 . 
     Upon such termination at the end point  140 , re-execution of the algorithm or subroutine  100  may be undertaken at any desired iterative speed consistent with, for example, other vehicle computational activity. 
     The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.