Method for Controlling a Hybrid Electric Vehicle Powertrain with Divided Power Flow Paths
First Claim
1. A method for enhancing reverse driving torque in a hybrid electric vehicle powertrain having an engine, an electric motor, an electric generator, a battery, gearing forming separate power flow paths to vehicle traction wheels from the engine and the motor and from the electric motor and from the generator, acting as a motor, during reverse drive, the electric generator and the battery being electrically coupled, and a controller for coordinating power delivery through the separate power flow paths during forward drive and during reverse drive, the motor operating in one direction during forward vehicle drive and in a direction opposite to the one direction during reverse vehicle drive, the method comprising the steps of:
- calculating a desired traction wheel torque in response to a driver demand for torque during reverse drive;
determining a need to boost reverse driving torque of the motor;
determining whether the battery has capacity to supply electric energy to the motor and to the generator acting as a motor to meet a boosted driver demand for reverse driving torque;
determining whether the engine should be on or off;
determining an engine torque adder to traction wheel torque when the engine is not fueled; and
adding the engine torque boost to reverse-driving torque whereby total reverse driving vehicle performance is enhanced.
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Accused Products
Abstract
A method is disclosed for enhancing reverse driving torque in a hybrid electric vehicle powertrain in which an electric motor is used for providing forward driving torque as well as reverse driving torque. An electric generator, functioning as a motor, supplies an added reverse driving torque using a gearset in which the engine provides a reverse driving reaction torque for the gearset.
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Citations
20 Claims
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1. A method for enhancing reverse driving torque in a hybrid electric vehicle powertrain having an engine, an electric motor, an electric generator, a battery, gearing forming separate power flow paths to vehicle traction wheels from the engine and the motor and from the electric motor and from the generator, acting as a motor, during reverse drive, the electric generator and the battery being electrically coupled, and a controller for coordinating power delivery through the separate power flow paths during forward drive and during reverse drive, the motor operating in one direction during forward vehicle drive and in a direction opposite to the one direction during reverse vehicle drive, the method comprising the steps of:
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calculating a desired traction wheel torque in response to a driver demand for torque during reverse drive; determining a need to boost reverse driving torque of the motor; determining whether the battery has capacity to supply electric energy to the motor and to the generator acting as a motor to meet a boosted driver demand for reverse driving torque; determining whether the engine should be on or off; determining an engine torque adder to traction wheel torque when the engine is not fueled; and adding the engine torque boost to reverse-driving torque whereby total reverse driving vehicle performance is enhanced. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for enhancing reverse driving torque in a split-power hybrid electric vehicle powertrain having an engine, an electric motor, an electric generator, a battery and a planetary gear unit with a ring gear, a planetary carrier and a sun gear;
- the engine being drivably connected to the carrier, the sun gear being drivably connected to the generator and the ring gear being drivably connected to vehicle traction wheels through torque transmitting gearing; and
a controller for coordinating power distribution from the engine and from the battery;
the motor operating in one direction during forward vehicle drive and in a direction opposite to the one direction during reverse vehicle drive, the method comprising the steps of;reducing fueling of the engine during reverse drive; determining a desired traction wheel torque in response to a driver demand for torque during reverse drive; determining a need to boost reverse driving torque of the motor; determining whether the battery has capacity to supply electric energy to the motor and to the generator acting as a motor to meet a boosted driver demand for reverse driving torque; determining an engine state indicating whether the engine should be on or off; determining limits of an engine torque adder to traction wheel torque when wheel torque is less than a torque limit; and adding the engine wheel torque adder to reverse-driving wheel torque whereby reverse driving vehicle performance is enhanced. - View Dependent Claims (9, 10, 11, 12, 13)
- the engine being drivably connected to the carrier, the sun gear being drivably connected to the generator and the ring gear being drivably connected to vehicle traction wheels through torque transmitting gearing; and
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14. A method for enhancing reverse driving torque in a split power hybrid electric vehicle powertrain having a throttle controlled engine, an electric motor, an electric generator, a battery and a planetary gear unit with a ring gear, a planetary carrier and a sun gear;
- the engine being drivably connected to the carrier, the sun gear being drivably connected to the generator and the ring gear being drivably connected to vehicle traction wheels through torque transmitting gearing; and
a controller for coordinating power distribution from the engine and from the battery, during forward drive;
the motor operating in one direction during forward vehicle drive and in a direction opposite to the one direction during reverse vehicle drive;
the method comprising the steps of;controlling fueling of the engine during reverse drive in response to a command by the controller when the controller receives a driver reverse drive power request; and operating the generator as a motor during reverse vehicle drive as the motor drives the ring gear in the opposite direction and the generator drives the sun gear in the one direction whereby the engine is driven in the one direction. - View Dependent Claims (15, 16, 17, 18)
- the engine being drivably connected to the carrier, the sun gear being drivably connected to the generator and the ring gear being drivably connected to vehicle traction wheels through torque transmitting gearing; and
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19. A method for enhancing reverse driving torque in a split power hybrid electric vehicle powertrain having a throttle controlled engine, an electric motor, an electric generator, a battery and a planetary gear unit with a ring gear, a planetary carrier and a sun gear;
- the engine being drivably connected to the carrier, the sun gear being drivably connected to the generator and the ring gear being drivably connected to vehicle traction wheels through torque transmitting gearing; and
a controller for coordinating power distribution from the engine and from the battery, the generator and the motor during forward drive;
the motor operating in one direction during forward vehicle drive and in a direction opposite to the one direction during reverse vehicle drive;
the method comprising the steps of;controlling fueling of the engine during reverse drive in response to a command by the controller when the controller receives a driver reverse drive power request; operating the generator as a motor during reverse vehicle drive as the motor drives the ring gear in the opposite direction and the generator drives the sun gear in the one direction whereby the engine is driven in the one direction; determining a battery power limit at repetitive time intervals by the controller and determining a threshold power limit at repetitive time intervals by the controller; computing an effective reverse power required in response to a driver request for power during reverse vehicle drive; allowing a ring gear torque boost if the driver request for power is less than the threshold power limit; and disallowing a ring gear torque boost if a driver request for power is greater than the threshold power limit. - View Dependent Claims (20)
- the engine being drivably connected to the carrier, the sun gear being drivably connected to the generator and the ring gear being drivably connected to vehicle traction wheels through torque transmitting gearing; and
Specification