Hybrid electric vehicle with enhanced battery control

• US 7,173,396 B2
• Filed: 09/10/2002
• Issued: 02/06/2007
• Est. Priority Date: 09/18/2001
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Gunji, Kenichirou
• Primary Examiner(s): Tso; Edward H.
• Application Number:
  US10/237,620
• Publication Number:
  US 20030052650A1
• Time in Patent Office: 1,610 Days
• Field of Search: 320/104, 320/128, 320/132, 320/130, 320/136, 320/134, 320/127, 320/162, 180/65.3, 180/65.5, 180/65.2, 180/65.1
• US Class Current: 320/132
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 23/08 for changing number of driven wheels , for switching from driving one axle to driving two or more axles B60K17/3515 takes precedence
• 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: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2050/143 Alarm means
• CPC Class Codes: B60W 2050/146 Display means
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 30/18018 Start-stop drive, e.g. in a traffic jam
• CPC Class Codes: B60W 30/18027 : Drive off, accelerating from standstill
• CPC Class Codes: B60W 30/18063 : Creeping
• CPC Class Codes: B60W 30/18118 : Hill holding
• CPC Class Codes: H01M 10/48 : Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/1446 : in response to parameters of a vehicle
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 10/92 : Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A method and system for enhanced battery control improves the performance of a hybrid electric vehicle (HEV). The HEV includes an internal combustion engine, at least one motor operable as a generator and a battery. A hybrid control module determines various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle. It also determines various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle. The allowances and periods of time may be used as limits that are imposed on commands for the motor.

Claims

1. A system for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the system comprising:

a block determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle; and

a block determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle.

3. The system as claimed in claim 1, further comprising:

a block estimating an actual state of charge (SOC) of the battery; and

a block calculating a discharge limit of the battery and a recharge limit of the battery in response to the estimated actual SOC of the battery, the discharge and recharge limits being used as constraints in determining various discharge and recharge allowances and in determining various periods of time.

4. The system as claimed in claim 3, wherein the various discharge and recharge allowances are limited when no information is available which is needed to estimate the actual SOC of the battery.

7. The system as claimed in claim 1, wherein both the internal combustion engine and the at least one motor are coupled to all road wheels of the hybrid electric vehicle to apply driving torque thereto.

9. The system as claimed in claim 1, wherein the maximum recharge allowance and the minimum period of time for recharge are determined in response to a request for torque absorption at engine start, a request for motor TCS, a request for duet control (shift up) and a request for motor action for roll-back avoidance (downhill);

and wherein the minimum recharge allowance and the maximum period of time for recharge are determined in response to a request for engine brake assist.

10. The system as claimed in claim 1, further comprising a device, within a passenger compartment of the hybrid electric vehicle, used to monitor the state of operation of the battery in relation to operating condition of the hybrid electric vehicle.

15. The system as claimed in claim 1, wherein the discharge allowances are related to operating conditions of the hybrid electric vehicle that reduce the charge of the battery, and wherein the recharge allowances are related to operating conditions of the hybrid electric vehicle that increase the charge of the battery.

2. A system for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the system comprising:

a block determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle; and

a block determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle,

wherein the determined periods of time are related to the determined discharge and recharge allowances such that a shorter period of time is set for a greater allowance.

16. The system as claimed in claim 2, wherein the discharge allowances are related to operating conditions of the hybrid electric vehicle that reduce the charge of the battery, and wherein the recharge allowances are related to operating conditions of the hybrid electric vehicle that increase the charge of the battery.

5. A system for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the system comprising:

a block determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle;

a block determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle;

a block estimating an actual state of charge (SOC) of the battery; and

a block calculating a discharge limit of the battery and a recharge limit of the battery in response to the estimated actual SOC of the battery, the discharge and recharge limits being used as constraints in determining various discharge and recharge allowances and in determining various periods of time,

wherein the various discharge and recharge allowances are determined based on open-end voltage of the battery when a measure of the open-end voltage is the only available information for estimating the actual SOC of the battery.

6. The system as claimed in claim 5, wherein, when the measure of the open-end voltage is higher than a predetermined high voltage threshold, a restricted recharge allowance is determined for different operating conditions of the hybrid electric vehicle, and, when the measure of the open-end voltage is lower than a predetermined low voltage threshold, a restricted discharge allowance is determined for different operating conditions of the hybrid electric vehicle.

8. A system for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the system comprising:

a block determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle; and

a block determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle,

wherein the maximum discharge allowance and the minimum period of time for discharge are determined in response to a request for engine start, a request for 4WD (slip), a request for duet control (shift down) and a request for motor action for roll-back avoidance (uphill); and

wherein the minimum discharge allowance and the maximum period of time for discharge are determined in response to a request for torque assist by motor and a request for motor running (creep start); and

wherein the intermediate discharge allowance and the intermediate period of time for discharge are determined in response to a request for 4WD start.

11. A system for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the system comprising:

means for determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle; and

means for determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle.

17. The system as claimed in claim 11, wherein the discharge allowances are related to operating conditions of the hybrid electric vehicle that reduce the charge of the battery, and wherein the recharge allowances are related to operating conditions of the hybrid electric vehicle that increase the charge of the battery.

12. A method for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the method comprising:

determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle; and

determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle.

18. The method as claimed in claim 12, wherein the discharge allowance are related to operating conditions of the hybrid electric vehicle that reduce the charge of the battery, and wherein the recharge allowances are related to operating conditions of the hybrid electric vehicle that increase the charge of the battery.

13. A computer readable storage medium having stored therein data representing instructions executable by a computer for enhanced battery control that improves the performance of a hybrid electric vehicle, the hybrid electric vehicle including an internal combustion engine and at least one motor operable as a generator and a battery, the computer readable storage medium comprising:

instructions for determining various discharge and recharge allowances limiting operation of the battery with different operating conditions of the hybrid electric vehicle; and

instructions for determining various periods of time limiting operation of the battery with different operating conditions of the hybrid electric vehicle.

19. The storage medium of claim 13, wherein the discharge allowances are related to operating conditions of the hybrid electric vehicle that reduce the charge of the battery, and wherein the recharge allowances are related to operating conditions of the hybrid electric vehicle that increase the charge of the battery.

14. A hybrid electric vehicle comprising:

an internal combustion engine;

at least one motor operable in response to motor commands, both the internal combustion engine and the motor being provided to apply driving torque to road wheels of the vehicle, the motor being operable as a generator;

a battery that is operable in discharge mode to energize the motor, the battery being operable in recharge mode when the motor operates as the generator;

a hybrid control module that is operable

to determine different requests on the motor in response to varying operating conditions of the vehicle;

to determine torque application/absorption commands in response to the different requests;

to determine various output and input margins, and various periods of time with the different requests;

to determine discharge and recharge clearances in response to the determined various output and input margins;

to estimate an actual state of charge (SOC) of the battery;

to determine a discharge limit and a recharge limit in response to the estimated actual SOC of the battery;

to determine a discharge allowance from the determined discharge limit and the determined discharge clearance;

to determine a recharge allowance from the determined recharge limit and the determined recharge clearance;

to use the determined period of time, discharge allowance and recharge allowance as limits that are imposed on the torque application/absorption commands to generate the motor commands; and

to apply the motor commands to the motor.

20. The vehicle of claim 14, wherein the discharge allowance is related to operating conditions of the hybrid electric vehicle that reduce the charge of the battery, and wherein the recharge allowance is related to operating conditions of the hybrid electric vehicle that increase the charge of the battery.