POWERTRAIN FOR A HYBRID VEHICLE WITH ALL-WHEEL DRIVE CAPABILITY AND METHOD FOR CONTROLLING WHEEL SLIP
First Claim
1. A powertrain for an all-wheel drive vehicle with forward and rearward sets of traction wheels, the powertrain comprising:
- an engine;
an electric generator;
an electric motor;
a geared transmission having a first torque delivery element connected drivably to the engine, a second torque delivery element connected drivably to the generator, and a torque output element;
the electric motor being drivably connected to the forward set of traction wheels and being electrically coupled to the generator; and
a multiple ratio gear unit drivably connecting the torque output element of the geared transmission to the rearward set of traction wheels, whereby mechanical energy is distributed to the rearward set of traction wheels and electrical energy is distributed to the forward set of traction wheels;
the multiple ratio gear unit comprising discrete ratio gearing with distinct ratio steps in a torque flow path from the torque output element of the geared transmission to the rearward traction wheels.
0 Assignments
0 Petitions
Accused Products
Abstract
A hybrid-electric powertrain and control method for a vehicle having forward traction wheels and rearward traction wheels in an all-wheel drive configuration. An engine and an electric motor deliver power through delivery paths to the traction wheels. The power delivery paths may have multiple ratio gearing so that more power can be delivered mechanically to improve powertrain performance and to allow the electric motor size to be reduced. The powertrain may include a controller for automatically balancing power distribution to the forward and rearward traction wheels to avoid wheel slip.
-
Citations
10 Claims
-
1. A powertrain for an all-wheel drive vehicle with forward and rearward sets of traction wheels, the powertrain comprising:
-
an engine;
an electric generator;
an electric motor;
a geared transmission having a first torque delivery element connected drivably to the engine, a second torque delivery element connected drivably to the generator, and a torque output element;
the electric motor being drivably connected to the forward set of traction wheels and being electrically coupled to the generator; and
a multiple ratio gear unit drivably connecting the torque output element of the geared transmission to the rearward set of traction wheels, whereby mechanical energy is distributed to the rearward set of traction wheels and electrical energy is distributed to the forward set of traction wheels;
the multiple ratio gear unit comprising discrete ratio gearing with distinct ratio steps in a torque flow path from the torque output element of the geared transmission to the rearward traction wheels. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method for controlling power distribution to front traction wheels and to rear traction wheels in a hybrid-electric powertrain for an all-wheel drive vehicle, the powertrain comprising an engine, a generator, an electric motor and a geared transmission establishing power distribution to the traction wheels, the method comprising the steps of:
-
determining whether an all-wheel drive mode is on;
determining power demand;
conditioning the powertrain for negative power distribution when the all-wheel drive mode is off and power demand is low; and
conditioning the powertrain for positive power distribution when the all-wheel drive mode is off and power demand is high.
-
-
7. A method for controlling power distribution to front traction wheels and to rear traction wheels in a hybrid-electric powertrain for an all-wheel drive vehicle, the powertrain comprising an engine, a generator, an electric motor and a geared transmission establishing power distribution to the traction wheels, the method comprising the steps of:
-
determining whether an all-wheel drive mode is on; and
conditioning the powertrain for positive power distribution when the all-wheel drive mode is on, whereby the generator delivers power to the front traction wheels. - View Dependent Claims (8)
-
-
9. A method for managing proportional power distribution to front traction wheels and to rear traction wheels in a hybrid-electric powertrain for an all-wheel drive vehicle, the method comprising:
-
determining whether an all-wheel drive mode is selected;
measuring wheel speeds at the traction wheels;
obtaining one set of engine speed and torque values for the engine when the all-wheel drive mode is selected;
obtaining another set of engine speed and torque values for the engine when a two-wheel drive mode is selected;
the sets of engine speed and torque values defining operating modes for the engine characterized by selected engine performance and efficiency for all-wheel drive operation and for two-wheel drive operation;
detecting rear wheel slip; and
decreasing engine torque and increasing motor torque when the rear wheels slip, whereby total wheel torque at the rear wheels remains unchanged.
-
-
10. A method for managing proportional power distribution to front traction wheels and to rear traction wheels in a hybrid-electric powertrain for an all-wheel drive vehicle, the method comprising:
-
determining whether an all-wheel drive mode is selected;
measuring wheel speeds at the traction wheels;
obtaining one set of engine speed and torque values for the engine when the all-wheel drive mode is selected;
obtaining another set of engine speed and torque values for the engine when a two-wheel drive mode is selected;
the sets of engine speed and torque values defining operating modes for the engine characterized by selected engine performance and efficiency for all-wheel drive operation and for two-wheel drive operation;
detecting front wheel slip; and
increasing engine torque and decreasing motor torque when the front wheels slip, whereby total torque at the rear wheels remains unchanged.
-
Specification