Hybrid vehicles

Abstract

A hybrid vehicle comprises an internal combustion engine, a traction motor, a starter motor, and a battery bank, all controlled by a microprocessor in accordance with the vehicle's instantaneous torque demands so that the engine is run only under conditions of high efficiency, typically only when the load is at least equal to 30% of the engine's maximum torque output. In some embodiments, a turbocharger may be provided, activated only when the load exceeds the engine's maximum torque output for an extended period; a two-speed transmission may further be provided, to further broaden the vehicle's load range. A hybrid brake system provides regenerative braking, with mechanical braking available in the event the battery bank is fully charged, in emergencies, or at rest; a control mechanism is provided to control the brake system to provide linear brake feel under varying circumstances.

1 - 9 . (canceled) 
     
     
         10 . A brake system for a hybrid vehicle, said vehicle comprising a drive train including an internal combustion engine operated to provide vehicle propulsive torque only during predetermined modes of operation of said vehicle and at least one traction motor and corresponding inverter/charger adapted to provide vehicle propulsive torque during predetermined modes of operation of said vehicle and to provide electrical energy responsive to torque from wheels of said vehicle during a regenerative braking mode of operation of said vehicle, a battery bank adapted to provide electrical energy to said motor as required and to accept charging energy from said motor when operated as a generator during said regenerative braking mode of operation of said vehicle, and a microprocessor for controlling the mode of operation of said vehicle, said brake system comprising:
 a brake pedal adapted to be operated by a driver of said. vehicle,   a hydraulic brake system coupled to said brake pedal and comprising at least one master cylinder and a number of wheel brakes operatively connected to said master cylinder for retarding said vehicle upon actuation of said pedal,   a sensor for providing a signal to said microprocessor responsive to motion of said brake pedal,   a sensor for providing a signal to said microprocessor responsive to the state of charge of said battery bank,   a device controllable by said microprocessor to vary the resistance to motion of said pedal during braking responsive to the amount of regenerative braking being provided,   wherein said microprocessor controls the amount of regenerative braking provided upon motion of said pedal responsive to the state of charge of said battery bank, and controls the resistance to motion of said pedal during braking responsive to the amount of regenerative braking being provided.   
     
     
         11 . The brake system of  claim 10 , wherein said device controllable by said microprocessor to vary the resistance to motion of said pedal during braking responsive to the amount of regenerative braking being provided comprises a pneumatic cylinder having a piston sliding therein, said piston being operated by said brake pedal, and comprising a vent passage including an orifice controllable by said microprocessor to control the resistance to motion of said pedal. 
     
     
         12 . The brake system of  claim 10 , wherein said at least one master cylinder is coupled to said brake pedal by an actuating rod arranged so that said pedal can be moved through a predetermined distance before said master cylinder begins to apply pressure to said wheel brakes. 
     
     
         13 . The brake system of  claim 10 , wherein said hydraulic brake system comprises a servo actuator and a vacuum pump driven by a motor responsive to electrical power supplied from said battery bank. 
     
     
         14 - 16 . (canceled)