Method and system for controlling the charging of a vehicle battery

• US 6,946,816 B2
• Filed: 01/21/2004
• Issued: 09/20/2005
• Est. Priority Date: 07/21/2001
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: BMW AG (Bayerische Motoren Werke AG)
• Inventors: Lang, Thomas, Pfab, Xaver
• Primary Examiner(s): Tibbits, Pia
• Application Number:
  US10/762,766
• Publication Number:
  US 20040239289A1
• Time in Patent Office: 608 Days
• Field of Search: 320/104, 320/136, 307/10.7, 307/10.1, 322/28, 700/293
• US Class Current: 320/104
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A control of the charging of a vehicle battery by means of a generator is disclosed. The generator also supplies an electric on-board power supply of a motor vehicle and an additional consuming device with electric power. However, the additional consuming device is supplied with electric power only when the power demand of the on-board power supply has been met. The supplying of the additional consuming device and the charging of the vehicle battery are controlled as follows: When the power demand of the additional consuming device has not been completely met, when a charging current, which flows from the generator into the vehicle battery, is higher than a limit value, and when the generator power additionally permits the supplying of the additional consuming device, the additional consuming device is supplied with power by the generator, and the charging current is adjusted such that it is lower than the maximally possible charging current while the generator power and the power demand of the on-board power supply are the same.

Claims

1. Method of controlling the charging of a vehicle battery, wherein

the vehicle battery is connected with a generator,

the generator supplies a consuming device of the vehicle and an additional consuming device with electric power, and

the generator supplying the additional consuming device with electric power only when the power requirement of the consuming device has been met,

wherein the supplying of the additional consuming device and the charging of the vehicle battery are controlled in that

when the power demand of the additional consuming device is not fully met,

when it is determined that a charging current, which flows from the generator into the vehicle battery, is higher than a limit value, and

when the generator power additionally permits the supplying of the additional consuming device,

the additional consuming device is supplied with power by the generator and the charging current is adjusted such that it is lower than the maximally possible charging current while the generator is able to supply an electric power demanded by the consuming device.

2. Method according to claim 1, wherein the additional consuming device is not supplied with electric power by the generator when the charging current is lower than the limit value.

3. Method according to claim 1, wherein the charging current is controlled to the limit value when the additional consuming device is supplied with power by the generator.

4. Method according to claim 1, wherein the limit value of the charging current is changed as a function of at least one variable, particularly as a function of the vehicle battery temperature or of the battery charging condition.

5. Method according to claim 1, wherein a charging condition of the vehicle battery is detected and wherein it is permitted that the charging current falls under the limit value when a supply demand of the additional consuming device exists and when the charging condition is higher than or at least equal to a defined minimal value.

6. System for controlling the charging of a vehicle battery, having

a control element for adjusting a charging current, by means of which a generator charges the vehicle battery (1),

a detection device for detecting whether the charging current exceeds a limit value, and

a control unit which is connected with the detection device and the control element and which has a connection for receiving a demand signal which signals an electric supply demand of an additional consuming device connected to the generator,

wherein the system is further developed such that, in the case of a supply demand of the additional consuming device, the charging current can be adjusted such by the control element that it is lower than the maximally possible charging current while the generator power and the power demand of other consuming device connected to the generator are the same.

7. System according to claim 6, having

a detection device for detecting the charging condition of the vehicle battery, wherein said detection device is connected to the vehicle battery and to the control unit,

wherein the control unit is further developed such that it controls the charging of the vehicle battery as a function of a detection signal of the detection device.

8. A method of controlling a charging of a battery in a vehicle including a generator for charging the battery and for supplying electric power to a consuming device and an additional consuming device, the method comprising:

supplying electric power to the additional consuming device by the generator only when the electric power supplied to the consuming device is at or above an electric power threshold; and

controlling the supplying of electric power to the additional consuming device and the charging of the vehicle battery if;

the power demand of the additional consuming device is below a power threshold;

it is determined that a charging current, which flows from the generator into the battery, is higher than a limit value; and

the generator power additionally permits the supplying of the additional consuming device.

9. The method according to claim 8, wherein the additional consuming device is supplied with power by the generator and the charging current is adjusted such that it is lower than a current threshold.

10. Method according to claim 8, wherein the additional consuming device is not supplied with electric power by the generator when the charging current is lower than the limit value.

11. Method according to claim 8, wherein the charging current is controlled to the limit value when the additional consuming device is supplied with power by the generator.

12. Method according to claim 8, wherein the limit value of the charging current is changed as a function of at least one variable, particularly as a function of the vehicle battery temperature or of the battery charging condition.

13. Method according to claim 8, wherein a charging condition of the vehicle battery is detected and wherein it is permitted that the charging current falls under the limit value when a supply demand of the additional consuming device exists and when the charging condition is higher than or at least equal to a defined minimal value.

14. In a system comprising a generator coupled to a vehicle battery, a first consuming device, and a second consuming device, a method of charging said vehicle battery comprising:

supplying power to said second consuming device by said generator if said generator is able to supply a demanded power to said first consuming device; and

controlling a charging current to said vehicle battery if;

said power supplied to said second consuming device is below a demanded power of said second consuming device;

said charging current is above a lower charging current threshold; and

said generator is able to supply said power to said second consuming device;

wherein controlling said charging current comprises adjusting said charging current such that said charging current is lower than an upper charging current threshold.

15. The method of claim 14, further comprising ceasing said supplying power to said second consuming device by said generator if said charging current falls below said lower charging current threshold.

16. The method of claim 14, further comprising adjusting said charging current to said lower charging current threshold while said generator is supplying said power to said second consuming device.

17. The method of claim 14, wherein said lower charging current threshold is dependent on a temperature of said battery vehicle.

18. The method of claim 14, wherein said lower charging current threshold is dependent on a charging condition of said battery vehicle.

19. A system comprising:

a current controlling element for adjusting a charging current flowing from a generator to a vehicle battery;

a current sensing device for generating a current signal indicative of said charging current;

a consuming device capable of receiving power from said generator, wherein said consuming device generates a demand signal indicative of a power demanded by said consuming device; and

a control unit adapted to control said current controlling element in response to said current signal and said demand signal;

wherein said control unit is adapted to control said current controlling element such that said charging current is lower than an upper charging current threshold while said generator supplies said consuming device with said demanded power.

20. The system of claim 19, further comprising:

a charging condition detector for generating a charging condition signal indicative of a charging condition of said vehicle battery; and

wherein said control unit is adapted to control said current controlling element in response to said charging condition signal.

21. In a system comprising a generator coupled to a vehicle battery, a first consuming device, and a second consuming device, a method of controlling a charging of said vehicle battery comprising:

supplying a first electric power to said first consuming device by said generator;

supplying a second electric power to said second consuming device by said generator if said first electric power is at or above an electric power threshold; and

controlling said second electric power and a charging current flowing from said generator to said vehicle battery if;

said second electric power supplied to said second consuming device is below a demanded power of said second consuming device;

said charging current is above a lower charging current threshold; and

said generator is able to supply said second electric power to said second consuming device.

22. The method of claim 21, further comprising adjusting said charging current such that it is lower than said lower charging current threshold while said generator is supplying said second electric power to said second consuming device.

23. The method of claim 21, further comprising ceasing said supplying second electric power to said second consuming device by said generator if said charging current falls below said lower charging current threshold.

24. The method of claim 21, further comprising adjusting said charging current to said lower charging current threshold while said generator is supplying said second electric power to said second consuming device.

25. The method of claim 21, wherein said lower charging current threshold is dependent on a temperature of said battery vehicle.

26. The method of claim 21, wherein said lower charging current threshold is dependent on a charging condition of said battery vehicle.

27. The method of claim 21, further comprising:

detecting a charging condition of said vehicle battery; and

permitting that said charging current fall below said lower charging current threshold when said charging condition of said vehicle battery is at or above a charging condition threshold.