Method for regulating the charging state of an energy accumulator for a vehicle comprising a hybrid drive

• US 8,565,947 B2
• Filed: 04/22/2008
• Issued: 10/22/2013
• Est. Priority Date: 04/28/2007
• Status: Expired due to Fees

• Current Assignee: Voith Patent Gmbh
• Original Assignee: Voith Patent Gmbh
• Inventors: Hoffmann, Rolf
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): LIN, ABBY YEE
• Application Number:
  US12/451,160
• Publication Number:
  US 20100217465A1
• Time in Patent Office: 2,009 Days
• Field of Search: 701/1, 701/22, 701/424, 180 651- 658, 320127-136, 320/166, 320/104, 903/903
• US Class Current: 701/22
• 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 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 40/13 Load or weight

Abstract

A method for regulating a charging state of an energy accumulator for a vehicle with a hybrid drive includes detecting a driving speed variable value of the vehicle and determining a nominal charging state of the energy accumulator as a function of the driving speed variable value by a control unit, detecting an actual charging state of the energy accumulator, comparing the actual charging state with the nominal charging state by the control unit, switching on an energy consumer by a charging state regulator, for at least partially discharging the energy accumulator when the actual charging state exceeds the nominal charging state, tabulating a first nominal charging state value as a function of the driving speed variable value by a characteristic curve, in order to determine the nominal charging state of the energy accumulator, and adapting the characteristic curve by the control unit when the vehicle is braked.

Claims

1. A method for regulating a charging state of an energy accumulator for a vehicle with a hybrid drive comprising:

detecting a driving speed variable value of the vehicle by a driving speed detection device and determining a nominal charging state of the energy accumulator as a function of the driving speed variable value by a control unit;

detecting an actual charging state of the energy accumulator by a charging state detection device;

comparing the actual charging state with the nominal charging state by said control unit;

switching on an energy consumer by a charging state regulator, for at least partially discharging the energy accumulator when the actual charging state exceeds the nominal charging state;

tabulating a first nominal charging state value as a function of the driving speed variable value by a characteristic curve, in order to determine the nominal charging state of the energy accumulator; and

adapting the characteristic curve by said control unit when the vehicle is braked, whereby a correction value determined by said control unit is added to the first nominal charging state value of the characteristic curve, said first nominal charging state value being associated with a real-time driving speed variable value during braking, and the first nominal charging state value which is increased or decreased by adding the correction value is stored as a new nominal charging state value of the characteristic curve for the real-time driving speed variable value,

wherein the correction value is determined by;

determining a difference value for the nominal charging state from a beginning nominal charging state value for the real-time driving speed variable value at a beginning of the braking and an end nominal charging state value for an end driving speed variable value at an end of the braking;

determining a difference value for the actual charging state from a beginning actual charging state value at the beginning of braking and an end actual charging state value of the energy accumulator at the end of braking;

comparing the difference value for the nominal charging state with the difference value for the actual charging state;

establishing the correction value for lowering the characteristic curve for a subsequent braking under the same braking conditions in such a way that the new nominal charging state value is smaller than the first nominal charging state value, if the difference value for the actual charging state is larger than the difference value for the nominal charging state, or

establishing the correction value for raising the characteristic curve for a subsequent braking under the same braking conditions in such a way that the new nominal charging state value is larger than the first nominal charging state value, if the difference value for the actual charging state is smaller than the difference value for the nominal charging state.

2. The method according to claim 1, wherein the hybrid drive has an electric motor that is switched on as the energy consumer.

3. The method according to claim 1,

wherein by establishing the correction value for lowering the characteristic curve, the first nominal charging state value of the characteristic curve that is associated with a higher driving speed variable value than the real-time driving speed variable value is reduced to the new nominal charging state value, if the first nominal charging state value associated with the higher driving speed variable value is larger than the new nominal charging state value;

and

by establishing the correction value for raising the characteristic curve, the first nominal charging state value of the characteristic curve that is associated with a lower driving speed variable value than the real-time driving speed variable value is increased to the new nominal charging state value, if the first nominal charging state value associated with the lower driving speed variable value is smaller than the new nominal charging state value.

4. The method according to claim 1, wherein the correction value has an absolute value that is determined by multiplying a difference between the difference value for the nominal charging state and the difference value for the actual charging state by a learning factor.

5. The method according to claim 4, wherein the learning factor has a value in the case of establishing the correction value for lowering the characteristic curve that islarger than in the case of establishing the correction value for raising the characteristic curve.

11. The method according to claim 4, wherein the learning factor is selected smaller than one.

6. A control unit for regulating a charging state of an energy accumulator for a vehicle with a hybrid drive, the control unit comprising a charging state regulator and an information memory,

wherein the control unit determine a nominal charging state of the energy accumulator as a function of a driving speed variable value of the vehicle that can be detected by a driving speed detection device and compares an actual charging state of the energy accumulator that can be detected by a charging state detection device with the nominal charging state,

wherein the charging state regulator switches on an energy consumer for at least partially discharging the energy accumulator when the actual charging state exceeds the nominal charging state,

wherein a characteristic curve is stored in the information memory, which curve tabulates nominal charging state values as a function of driving speed variable values,

wherein the control unit determines the nominal charging state of the energy accumulator by determining a first nominal charging state value of the characteristic curve and

adapts the characteristic curve when the vehicle is braked by determining a correction value that is added to the first nominal charging state value of the characteristic curve,

wherein the first nominal charging state value is associated with a real-time driving speed variable value during braking, and

wherein the first nominal charging state value that is increased or decreased by adding the correction value is stored as a new nominal charging state value of the characteristic curve for the real-time driving speed variable value,

wherein the correction value is determined by:

determining a difference value for the nominal charging state from a beginning nominal charging state value for the real-time driving speed variable value at a beginning of the braking and an end nominal charging state value for an end driving speed variable value at an end of the braking;

determining a difference value for the actual charging state from a beginning actual charging state value at the beginning of braking and an end actual charging state value of the energy accumulator at the end of braking;

comparing the difference value for the nominal charging state with the difference value for the actual charging state;

establishing the correction value for lowering the characteristic curve for a subsequent braking under the same braking conditions in such a way that the new nominal charging state value is smaller than the first nominal charging state value, if the difference value for the actual charging state is larger than the difference value for the nominal charging state, or

establishing the correction value for raising the characteristic curve for a subsequent braking under the same braking conditions in such a way that the new nominal charging state value is larger than the first nominal charging state value, if the difference value for the actual charging state is smaller than the difference value for the nominal charging state.

7. The control unit according to claim 6, wherein the energy consumer switched on by the charging state regulator is an electric motor.

8. A vehicle comprising:

a hybrid drive;

an energy accumulator;

a driving speed detection device for detecting a driving speed variable value of the vehicle;

a charging state detection device for detecting an actual charging state of energy accumulator; and

a control unit determining a nominal charging state of the energy accumulator as a function of the driving speed variable value of the vehicle detected by the driving speed detection device and comparing the actual charging state of the enemy accumulator detected by the charging state detection device with the nominal charging state,

the control unit having a charging state regulator, the charging state regulator switching on an energy consumer for at least partially discharging the energy accumulator when the actual charging state exceeds the nominal charging state,

the control unit comprising an information memory, whereby a characteristic curve is stored in the information memory, which curve tabulates nominal charging state values as a function of driving speed variable values,

the control unit determining the nominal charging state of the energy accumulator by determining a first nominal charging state value of the characteristic curve,

the control unit adapting the characteristic curve when the vehicle is braked by determining a correction value that is added to the first nominal charging state value of the characteristic curve, said correction value being associated with a real-time driving speed variable value during braking, and the first nominal charging state value which is increased or decreased by adding the correction value is stored as a new nominal charging state value of the characteristic curve for the real-time driving speed variable value.

wherein the correction value is determined by;

determining a difference value for the nominal charging state from a beginning nominal charging state value for the real-time driving speed variable value at a beginning of the braking and an end nominal charging state value for an end driving speed variable value at an end of the braking;

determining a difference value for the actual charging state from a beginning actual charging state value at the beginning of braking and an end actual charging state value of the energy accumulator at the end of braking;

comparing the difference value for the nominal charging state with the difference value for the actual charging state;

establishing the correction value for lowering the characteristic curve for a subsequent braking under the same braking conditions in such a way that the new nominal charging state value is smaller than the first nominal charging state value, if the difference value for the actual charging state is larger than the difference value for the nominal charging state, or

establishing the correction value for raising the characteristic curve for a subsequent braking under the same braking conditions in such a way that the new nominal charging state value is larger than the first nominal charging state value, if the difference value for the actual charging state is smaller than the difference value for the nominal charging state.

9. The vehicle according to claim 8, wherein the energy accumulator has a maximum capacity to take up a maximum braking energy of the vehicle at a maximum vehicle speed.

10. The vehicle according to claim 8, wherein the energy accumulator is a multi-layer capacitor.

12. The vehicle according to claim 8, wherein the energy accumulator is a double-layer capacitor.