Regenerative vehicle launch
First Claim
1. A method of launching a vehicle from a substantially static condition, said vehicle having a drivetrain comprising an internal combustion engine including an engine output member, a electric machine including a stator and rotor, and a gear set operatively coupling said internal combustion engine output, said rotor and a gear set output member of said gear set, said gear set output member being operatively coupled to at least one drive wheel for propelling the vehicle, wherein said generator is effective as an electric brake reaction element to control torque transfer between said engine output member and said gear set output member, the method comprising:
- detecting a predetermined set of vehicle drivetrain operating parameters;
controlling a torque influencing electric machine parameter to apply an amount of generator torque to the rotor as a function of said predetermined set of vehicle operating parameters thereby converging respective speeds of the rotor and the gear set output member; and
,when the speeds of the rotor and the gear set output member attain a predetermined speed differential relationship, controlling the rotor speed to the gear set output member speed.
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Accused Products
Abstract
A hybrid electric vehicle includes an internal combustion engine, a multi-speed automatic transmission, and an electric machine operable in a motoring mode and a generating mode. A compound planetary gear set operatively couples the engine, transmission and electric machine. The electric machine is operable during periods of vehicle launch to provide a reaction torque for the planetary gearset such that torque is supplied to the input of the transmission and the reaction torque energy is converted to electrical energy for storage in a vehicle battery pack battery. The method employs a combination of open loop torque control and closed loop speed controls responsive to rotational parameters of the vehicle drivetrain including engine speed, electric machine rotor speed and transmission input speed to control the generator torque of the electric machine to thereby produce the reaction torque for accelerating the vehicle and for producing electrical power during the vehicle launch.
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Citations
12 Claims
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1. A method of launching a vehicle from a substantially static condition, said vehicle having a drivetrain comprising an internal combustion engine including an engine output member, a electric machine including a stator and rotor, and a gear set operatively coupling said internal combustion engine output, said rotor and a gear set output member of said gear set, said gear set output member being operatively coupled to at least one drive wheel for propelling the vehicle, wherein said generator is effective as an electric brake reaction element to control torque transfer between said engine output member and said gear set output member, the method comprising:
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detecting a predetermined set of vehicle drivetrain operating parameters; controlling a torque influencing electric machine parameter to apply an amount of generator torque to the rotor as a function of said predetermined set of vehicle operating parameters thereby converging respective speeds of the rotor and the gear set output member; and
,when the speeds of the rotor and the gear set output member attain a predetermined speed differential relationship, controlling the rotor speed to the gear set output member speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of launching a vehicle from a substantially static condition, said vehicle having a drivetrain comprising an internal combustion engine including an engine output member, a electric machine including a rotor, and a gear set operatively coupling said internal combustion engine output, said rotor and a gear set output member of said gear set, said gear set output member being operatively coupled to at least one drive wheel for propelling the vehicle, a first selectably engageable friction device for directly coupling said gear set output member to said engine output member, and a second selectably engageable friction device for directly coupling said gear set output member to said rotor, wherein said electric machine is effective as an electric brake reaction element to control torque transfer between said engine output member and said gear set output member, the method comprising:
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detecting a predetermined set of vehicle drivetrain operating parameters; controlling a torque influencing electric machine parameter to apply an amount of generator torque to the rotor as a function of said predetermined set of vehicle operating parameters thereby converging respective speeds of the rotor and the gear set output member; when the speeds of the rotor and the gear set output member attain a predetermined speed differential relationship, controlling the rotor speed to the gear set output member speed; engaging said first and second friction devices while controlling the rotor speed to the gear set output member speed. - View Dependent Claims (11)
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12. A method of launching a vehicle from a substantially static condition, said vehicle having a drivetrain comprising an internal combustion engine including an engine output member, a electric machine including a rotor, and a gear set operatively coupling said internal combustion engine output, said rotor and a gear set output member of said gear set, said gear set output member being operatively coupled to at least one drive wheel for propelling the vehicle, a first selectably engageable friction device for directly coupling said gear set output member to said engine output member, and a second selectably engageable friction device for directly coupling said gear set output member to said rotor, wherein said electric machine is effective as an electric brake reaction element to control torque transfer between said engine output member and said gear set output member, the method comprising:
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detecting a predetermined set of vehicle drivetrain operating parameters; performing an open loop control of a torque influencing electric machine parameter to apply an amount of generator torque to the rotor as a function of said predetermined set of vehicle operating parameters thereby converging respective speeds of the rotor and the gear set output member; when the speeds of the rotor and the gear set output member attain a predetermined speed differential relationship, performing a closed loop control of the rotor speed to the gear set output member speed; when the vehicle speed exceeds a predetermined threshold, fully engaging said second friction device and progressively engaging said first friction device from an initial engagement pressure to a final engagement pressure, said initial and final engagement pressures being determined as a function of a predetermined measure of engine torque.
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Specification