Method and apparatus for vehicle regenerative braking

Abstract

18A method and an apparatus ( 12 ) which senses whether a vehicle ( 10 ) is being decelerated by the use of regenerative braking and which selectively and automatically activates frictional braking assemblies ( 60 - 66 ) if such regenerative braking has not been achieved.

1 . An assembly comprising a selectively energizable frictional braking assembly; a sensor which determines whether regenerative braking has been applied to a vehicle and which generates a signal in the absence of the application of said regenerative braking to said vehicle; and a controller assembly which is coupled to said selectively energizable frictional braking assembly and to said sensor, which receives said signal from said sensor and, in response to said receipt of said signal from said sensor, selectively activates said frictional braking assembly, effective to brake said vehicle.  
     
     
         2 . The assembly of  claim 1  wherein said sensor comprises a wheel speed sensor.  
     
     
         3 . The assembly of  claim 1 , wherein said controller further determines if a certain amount of regenerative braking has occurred within a certain predetermined amount of time and, in response to a determination that said certain amount of regenerative braking has not occurred within said predetermined amount of time, said controller selectively and automatically activates said frictional braking assembly, effective to brake said vehicle.  
     
     
         4 . The assembly of  claim 1  wherein said assembly further comprises a selectively movable member which is coupled to said controller and which defines a certain amount of regenerative braking and which communicates said defined and certain amount of regenerative braking to said controller.  
     
     
         5 . The assembly of  claim 4  wherein said selectively movable member comprises a brake pedal.  
     
     
         6 . The assembly of  claim 4  wherein said controller stores said defined certain amount of regenerative braking and compares said stored amount of regenerative braking with said signal from said sensor and, based upon said comparison, energizes said frictional braking assembly.  
     
     
         7 . A vehicle comprising at least one wheel which will be selectively braked; a frictional brake assembly which is selectively coupled to said at least one wheel; a regenerative braking assembly; a sensor which measures a speed of said vehicle and which produces a first signal which is indicative of said measured speed; a brake request member which selectively generates a second signal which represents a certain amount of desired vehicular deceleration; and a controller which is coupled to said brake request member, to said frictional brake assembly, and to said speed sensor, said controller receiving said second signal and, in response to said receipt of said second signal, said controller attempts to decelerate said vehicle by use of said regenerative braking assembly, said controller further receiving said first signal and using said first and second signals to determine whether said vehicle has been decelerated and, based upon said determination, selectively brakes said at least one wheel by use of said frictional brake assembly.  
     
     
         8 . The vehicle of  claim 7  wherein said regenerative braking assembly comprises a motor and a battery.  
     
     
         9 . The vehicle of  claim 7  wherein said frictional braking assembly comprises a wheel braking portion and a pneumatic control which selectively causes said wheel braking portion to selectively decelerate said vehicle.  
     
     
         10 . The vehicle of  claim 7  wherein said brake request member comprises a brake pedal.  
     
     
         11 . The vehicle of  claim 7  wherein said sensor comprises a wheel speed sensor.  
     
     
         12 . A method for braking a vehicle comprising the steps of: 
 initially attempting to regeneratively brake said vehicle;    determining whether said vehicle has been regeneratively braked; and    automatically causing said vehicle to be frictionally braked if said vehicle has failed to be regeneratively braked.    
     
     
         13 . The method of  claim 12  wherein said step of determining whether said vehicle has been regeneratively braked comprises the steps of receiving a certain value; creating a second value; and comparing said second value to said certain value.  
     
     
         14 . The method of  claim 13  wherein said second value comprises a sensed amount of deceleration of said vehicle.  
     
     
         15 . The method of  claim 14  wherein said certain value comprises a deceleration value which is dependent upon the position of a brake pedal.  
     
     
         16 . The method of  claim 12  wherein said method further comprises the step of providing status information that said vehicle has failed to be regeneratively braked.  
     
     
         17 . The method of  claim 12  wherein said vehicle is of the type having a transmission which outputs torque and wherein said step of initially attempting to regeneratively brake said vehicle comprises the step of providing a flywheel assembly; and coupling said flywheel assembly to said transmission.  
     
     
         18 . The method of  claim 12  wherein said vehicle is of the type having at least one wheel and wherein said step of determining whether said vehicle has been regeneratively braked comprises the steps of providing a sensor; and coupling said sensor to said at least one wheel, effective to allow said sensor to generate an output signal indicative of the speed of said at least one wheel.  
     
     
         19 . The method of  claim 18  wherein said step of determining whether said vehicle has been regeneratively braked further comprises the step of calculating a certain amount of deceleration of said at least one wheel.