Maximized regenerative braking vehicle braking controller

• US 5,378,053 A
• Filed: 12/07/1993
• Issued: 01/03/1995
• Est. Priority Date: 12/07/1993
• Status: Expired due to Fees

• Current Assignee: Robert Bosch Technology Corporation
• Original Assignee: Alliedsignal Inc.
• Inventors: Phipps, Jack R., Patient, Daniel J.
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US08/163,252
• Time in Patent Office: 392 Days
• Field of Search: 303/3, 303/2, 303/6.01, 303/15-17, 303/, 303/20, 303/9.62, 303/9.61, 303/14, 303/10, 303/100, 303/105, 303/107, 303/111, 303/113.5, 303/112, 303/115.2, 303/110, 303/93, 303/9 2, 188/181 T, 188/159, 188/271, 188/158, 188/156, 188/106 P, 188/106 R, 188/106 F, 188/349, 364/426.01, 364/426.02, 364/426.03, 180/65.1, 180/65.8, 180/197, 180/165, 318/371
• US Class Current: 303/3
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0076 relating to braking
• CPC Class Codes: B60L 3/108 whilst braking, i.e. ABS
• CPC Class Codes: B60L 50/50 using propulsion power supplied by batteries or fuel cells
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/12 for vehicles propelled by dc motors
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 13/586 the retarders being of the electric type
• CPC Class Codes: B60T 13/74 : with electrical assistance or drive
• CPC Class Codes: B60T 2270/602 : ABS features related thereto
• CPC Class Codes: B60W 10/08 : including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 : with wheel brakes
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

A vehicle powered by an electric motor which may be operated as a generator to effect regenerative braking of certain vehicle wheels in combination with individual friction brakes associated with other wheels. A commanded vehicle deceleration is apportioned among the wheels by determining the maximum regenerative braking deceleration achievable by drive wheels, and braking the vehicle occurs solely by regenerative braking so long as the commanded deceleration is less than the determined maximum deceleration. When a commanded deceleration exceeds the determined maximum, the regenerative braking is supplemented with friction braking of the other wheels while the maximum regenerative braking is maintained. The maximum regenerative braking of the certain wheels may be supplemented with additional friction braking of those same certain wheels, but this occurs only if the combined deceleration of the regenerative braking of the certain wheels and the friction braking of the other wheels is inadequate to achieve the commanded deceleration.

Claims

1. In an electrically powered apparatus having front drive wheels coupled to and powered by at least one electric motor selectively operated as a generator to effect regenerative braking of said front wheels, and having individual friction brakes associated with, said front wheels and with rear wheels, the method of apportioning a commanded vehicle deceleration braking task among the wheels comprising:

determining the maximum regenerative braking deceleration achievable by said front wheels;

braking the vehicle solely by regenerative braking at the front wheels so long as the commanded deceleration is less than the determined maximum deceleration;

maintaining the maximum regenerative braking and supplementing the regenerative braking with friction braking of said rear wheels and in the event the commanded deceleration exceeds the determined maximum;

further supplementing the maximum regenerative braking of said front wheels with additional friction braking of those front wheels if the combined deceleration of the regenerative braking of said front wheels and the friction braking of said rear wheels is inadequate to achieve the commanded deceleration; and

sensing vehicle speed and disabling the regenerative braking when vehicle speed is below a predetermined threshold such that braking is achieved solely by friction braking of said front and rear wheels.

2. The method of claim 1 wherein the predetermined threshold is about three miles per hour.

3. The method of claim 1 wherein the step of determining the maximum regenerative braking deceleration includes:

sensing for the maximum deceleration prior to wheel slippage due to surface friction limitations; and

determining the deceleration associated with the maximum torque that said electric motor can absorb without damage, and selecting the smaller deceleration as the maximum.

4. The method of claim 3 wherein the maximum regenerative braking is reduced slightly in the event that the maximum deceleration is determined by friction limitations.

5. The method of claim 1 including the additional step of:

sensing for the maximum deceleration prior to wheel slippage due to surface friction limitations for each of said drive wheels; and

applying the additional frictional braking only to wheels which are decelerating at a rate which is less the corresponding sensed maximum deceleration.