CN-109664877-B - Regenerative hybrid vehicle braking system and method

Abstract

Methods and systems for operating a hybrid vehicle during conditions in which vehicle braking is requested are provided. In one example, regenerative braking is assigned to an axle in response to an antilock braking system being activated in response to wheel torque of the corresponding axle. In addition, friction braking torque is distributed to the axle in response to the antilock braking system being activated.

Inventors

• Dell Scott Krenbez
• David John Messiah
• ZHAO YANAN
• KUANG MINGLANG
• Werther Joseph Ottoman
• Joseph Jay Torres
• Stanley L. Bauer Jr.

Assignees

• 福特全球技术公司
• 福特全球技术公司

Dates

Publication Date

20260421

Application Date

20181009

Priority Date

20171013

Claims (14)

1. 1. A vehicle operation method, the vehicle operation method comprising: in response to activation of the antilock braking system, adjusting the regenerative torque of the spindle to a lower magnitude of the low pass filtered spindle trim torque of the right wheel and the low pass filtered spindle trim torque of the left wheel; the method additionally includes adjusting the regenerated torque of the layshaft to a lower magnitude of the low pass filtered layshaft adjustment torque of the right wheel and the low pass filtered layshaft adjustment torque of the left wheel.
2. 2. The method of claim 1, further comprising applying a friction brake in response to activating the anti-lock braking system.
3. 3. The method of claim 2, wherein the anti-lock braking system is activated via activation of a brake line pressure regulator valve.
4. 4. The method of claim 1, wherein the regenerative torque of the spindle is provided via a motor of a rear drive unit.
5. 5. The method of claim 1, further comprising adjusting a regenerative torque of the spindle in response to a requested braking torque provided via a human driver when the antilock braking system is not activated.
6. 6. The method of claim 1, wherein torque is provided to the main shaft via an engine and an electric machine.
7. 7. The method of claim 1, further comprising adjusting a friction brake of the spindle to a torque determined by subtracting the regenerative torque of the spindle from a brake adjustment torque of the spindle.
8. 8. The method of claim 1, the method further comprising: the regenerated torque of the layshaft is additionally adjusted to a lower magnitude of the low-pass filtered layshaft adjustment torque of the right wheel and the low-pass filtered layshaft adjustment torque of the left wheel in response to a difference between a possible regenerated braking torque of the vehicle and the regenerated torque of the main shaft.
9. 9. The method of claim 8, wherein the primary shaft is a shaft of a vehicle that receives all driveline power when no wheel slip is detected, and the secondary shaft is a shaft of a vehicle that is capable of receiving power from a driveline when positive driveline torque generates wheel slip, but does not receive positive power from a driveline when no wheel slip is detected.
10. 10. A vehicle system, the vehicle system comprising: an anti-lock friction braking system comprising four friction brakes; A first motor; a second motor, and A controller comprising executable instructions stored in a non-transitory memory that cause the controller to filter wheel torque of a first axle via a first low pass filter having a first cutoff frequency and filter wheel torque of a second axle via a second low pass filter having a second cutoff frequency, the vehicle system further comprising further instructions to adjust a regenerative torque of a main axle to a lower magnitude of a low pass filtered main axle adjustment torque of a right wheel and a low pass filtered main axle adjustment torque of a left wheel, the vehicle system further comprising further instructions to adjust a regenerative torque of a countershaft to the lower magnitude of the low pass filtered auxiliary axle adjustment torque of the right wheel and the low pass filtered auxiliary axle adjustment torque of the left wheel.
11. 11. The vehicle system of claim 10, wherein the main shaft is a shaft of a vehicle that receives all driveline power when wheel slip is not detected.
12. 12. The vehicle system of claim 10, further comprising further instructions to apply at least one of the four friction brakes in response to activating the anti-lock friction braking system.
13. 13. The vehicle system of claim 10, wherein the first cutoff frequency is lower than the second cutoff frequency.
14. 14. The vehicle system of claim 13, wherein the first cutoff frequency is based on inertia of the first electric machine, wherein the second cutoff frequency is based on inertia of the second electric machine, and wherein the first electric machine and the second electric machine provide torque to a vehicle driveline.

Description

Regenerative hybrid vehicle braking system and method Technical Field The present invention relates generally to methods and systems for controlling regenerative braking of a hybrid vehicle. The method and system may be particularly useful for four-wheel drive hybrid vehicles. Background/summary of the invention The kinetic energy of the hybrid vehicle may be converted into electrical energy via an electric machine in the driveline of the hybrid vehicle. Specifically, wheel torque may be converted to electrical energy via an electric machine, which may be referred to as regenerative braking. The electrical energy may be stored in the electrical energy storage device until the electrical energy is subsequently used to propel the vehicle. The electric machine may have a large inertia if the electric machine provides a large amount of torque to propel the vehicle. The larger inertia may be related to the number of windings in the motor and the mass of the armature of the motor. An electric machine with a large inertia may be used to provide a desired vehicle acceleration rate. However, the greater inertia and/or magnetic field strength of the motor may make it more difficult to mitigate the possibility of wheel lock-up during wheel braking if the motor is providing regenerative braking. It may be desirable to provide regenerative braking while providing anti-lock wheel control during vehicle braking so that the vehicle may be decelerated at a desired rate and so that at least a portion of the vehicle's kinetic energy may be captured. The inventors herein have recognized the above-mentioned problem and have developed a vehicle operating method that includes adjusting a regenerative torque of a main axle to a lower magnitude of a low-pass filtered main axle adjustment torque of a right wheel and a low-pass filtered main axle adjustment torque of a left wheel in response to activation of an antilock braking system. By adjusting the adjustment torque of the main axle in response to activation of the anti-lock braking system in response to a lower magnitude of the low pass filtered main axle adjustment torque of the right wheel and the low pass filtered main axle adjustment torque of the left wheel, it is possible to provide regenerative vehicle braking while also adjusting wheel speed even though the electric machine of the driveline has a large inertia. In one example, the adjustment torque of the wheels may be decomposed into a regenerative braking torque and a friction braking torque. The regenerative braking torque of the wheels may include a lower braking modulation torque frequency and the friction braking torque of the wheels may include a higher modulation torque frequency such that the motor torque does not have to be responsive to the higher wheel modulation torque frequency. On the other hand, the friction brake may be responsive to a higher wheel adjustment torque frequency such that the likelihood of wheel locking while regenerative braking is in progress may be reduced. In addition, the regenerative and friction braking torques of the layshaft may be responsive to other modulated torque frequencies to compensate for inertia and vehicle weight distribution of other electric machines that provide regenerative braking to the layshaft. The present invention may provide several advantages. For example, the method may improve the storage of kinetic energy of the vehicle into electrical energy. In addition, the method may reduce the likelihood of wheel locking even if the vehicle includes an electric machine with a large inertia and/or magnetic field. Additionally, the method compensates for wheel torque control during conditions where regenerative braking may be limited due to abnormal vehicle conditions. It should be understood that the above summary is provided to introduce a set of concepts in a simplified form that are further described in the detailed description. The above summary is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Drawings FIG. 1A is a schematic illustration of a hybrid vehicle driveline. Fig. 1B is a schematic diagram of an engine of a hybrid vehicle driveline. FIG. 1C is a schematic illustration of an alternative hybrid vehicle driveline. FIG. 2 is a schematic illustration of a hybrid vehicle powertrain including a controller for various powertrain components. FIG. 3 is a schematic illustration of a dual clutch transmission located in a hybrid vehicle driveline. Fig. 4 shows a flowchart of a method for controlling braking of a hybrid vehicle. FIG. 5 illustrates a predictive vehicle operation sequence according to the method of FIG. 4. Detailed Description The following description relates to systems and methods