Battery monitoring and deceleration dependent fuel-saving charging system

• US 5,528,148 A
• Filed: 11/23/1994
• Issued: 06/18/1996
• Est. Priority Date: 07/13/1988
• Status: Expired due to Term

• Current Assignee: Charles W Bradley
• Original Assignee: Electronic Development Inc.
• Inventors: Rogers, Wesley A.
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US08/344,470
• Time in Patent Office: 573 Days
• Field of Search: 324/426, 324/427, 324/428, 324/433, 320/39, 320/40, 322/28, 322/38, 322/7, 322/9, 322/29
• US Class Current: 320/137
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3832 without measurement of battery voltage
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10S 320/10 Nonbattery load controls charging
• CPC Class Codes: Y10S 320/21 State of charge of battery

Abstract

The present invention relates to a battery monitoring and charging system capable of determining when charging conditions are favorable, thereby adjusting the charging level to maximize fuel saving. In particular, the system increases the alternator field current to charge a battery during vehicle deceleration so that vehicle momentum, instead of engine power, is used to torque the alternator shaft. The system controls the alternator field current with a voltage regulator. The voltage regulator senses the charge level of the battery, the amplitude and direction of the battery current load, and vehicle operating conditions to provide the proper current into the alternator rotor for maximum fuel savings. The voltage regulator may be a non-microprocessor or a microprocessor controlled device.

Claims

1. An apparatus for charging a battery used for energizing a load, comprising:

a first circuit for monitoring the state of charge of the battery;

a control circuit, responsive to the first circuit, for providing a first control signal when the battery state of charge is above a preselected first state of charge and a second control signal when the battery state of charge is below the first state of charge, the first control signal being different from the second control signal;

a second circuit for providing a load signal indicating the amplitude and polarity of the current load on the battery, wherein the control circuit is responsive to the second circuit and provides a third control signal when the load signal is above a preselected first load and provides one of the first and second control signals when the load signal is below the first load, the first control signal being different from the third control signal; and

a battery charging device, responsive to the control circuit, having an output voltage for providing a first charging voltage level in response to the first control signal and a second charging voltage level and a charging current in response to the second control signal, and a third charging voltage level and a charging current in response to the third control signal, the first charging voltage level being lower than the second charging voltage level.

2. The apparatus of claim 1 wherein the first state of charge is a percentage of the full charge condition of the battery.

3. The apparatus of claim 2 wherein the percentage of the full charge is representative of a substantially discharged battery charge that has not yet discharged to a level that damages the battery.

4. The apparatus of claim 1 wherein the control circuit further comprises:

a circuit for determining whether the battery state of charge is above or below the first state of charge;

a modulator circuit for providing a variable duty cycle output signal, responsive to the determining circuit and the second circuit, whereby the modulator circuit output has one of a first duty cycle when the battery state of charge is at or above the first state of charge and the load signal is below the first load, a second duty cycle when the battery state of charge is below the first state of charge, and a third duty cycle when the load signal is above the first load, the first duty cycle being different than the second and third duty cycles; and

wherein the battery charging device is responsive to the duty cycle of the modulated output signal for providing the first, second, and third charging voltages in response to the first, second, and third duty cycle outputs, respectively.

5. The apparatus of claim 4 further comprising a fuel burning engine for operating the battery charging device to provide the output voltage, whereby the engine consumes less fuel when the battery charging device produces the first charging voltage level than when the battery charging device produces one of the second and third charging voltage levels.

6. The apparatus of claim 5 further comprising an automotive vehicle having an electrical system connected to the battery and containing the battery, first measuring circuit, second sensing circuit, control circuit, battery charging device, and engine.

7. The apparatus of claim 6 further comprising a circuit for sensing deceleration of the automotive vehicle, wherein the control circuit provides a fourth control signal during sensed decelerations, wherein the battery charging device provides a fourth charging voltage level and a charging current in response to the fourth control signal, the fourth charging voltage level being greater than the first charging voltage level.

8. The apparatus of claim 7 wherein the battery charging device is an alternator and the second, third, and fourth charging voltages are the same.

9. The apparatus of claim 4 wherein the first charge voltage level and the first duty cycle correspond to the battery charging device producing a zero alternator current output.

10. The apparatus of claim 1 wherein the first charging voltage corresponds to no alternator output current.

11. A method of controlling the output voltage delivered by a battery charging device to a battery comprising the steps of:

(a) monitoring the state of charge of the battery;

(b) determining whether the state of charge of the battery is above or below some predetermined charge level;

(c) maintaining the output produced by the battery charging device at a first voltage level and a charging current when the state of charge of the battery is below the predetermined charge level and at a second voltage level when the state of charge is above the predetermined charge level, the second voltage level being lower than the first level;

(d) monitoring the amplitude and polarity of the current load on the battery;

(e) determining whether the current load is above or below some predetermined load amplitude; and

(f) maintaining the output produced by the battery charging device at one of the first and second voltage levels when the current load is below the predetermined load amplitude and at the first voltage level when the load current is above the predetermined load amplitude.

12. The method of claim 11 wherein step (c) further comprises maintaining the first voltage level at a voltage that is greater than the rated voltage capacity of the battery for charging the battery.

13. The method of claim 12 wherein step (c) further comprises determining when the battery state of charge falls below the predetermined charge level and thereafter maintaining the battery charging device at the first voltage level and charging current until the battery has a full charge.

14. The method of claim 11 wherein step (c) further comprises maintaining the second voltage level that is insufficient to place a charging current on the battery.

15. The method of claim 11 wherein the second voltage level corresponds to no charging current.

16. The method of claim 11 wherein step (b) comprises determining whether the state of charge is above or below a predetermined percentage of the full charge condition of the battery, the percentage being selected from between 40% and 100%.

17. The method of claim 11 wherein the monitoring step (a) comprises monitoring the state of charge of a battery in an automotive vehicle, the method further comprises the steps of

(g) monitoring the speed of the vehicle;

and

(h) determining whether or not the vehicle is decelerating;

and wherein the maintaining step (f) further comprises;

(f'"'"') maintaining the battery charging device output at the first voltage level when the load current is above the predetermined load amplitude, when the state of charge is below the predetermined charge threshold or when the vehicle is decelerating; and

(f") maintaining the battery charging device output at the second voltage level when the load current is below the predetermined load amplitude, the state of charge is above the predetermined charge threshold, and the vehicle is not decelerating.

18. A method of controlling the output voltage delivered by a battery charging device to a battery comprising the steps of:

(a) monitoring the state of charge of the battery;

(b) determining whether the state of charge of the battery is above or below some predetermined charge level;

(c) maintaining the output produced by the battery charging device at a first voltage level and a charging current when the state of charge of the battery is below the predetermined charge level and at a second voltage level when the state of charge is above the predetermined charge level, second voltage level being lower than the first level and at a voltage corresponding to placing a trickle charge current on the battery.

19. A method of controlling the output voltage delivered by a battery charging device to a battery in an automatic vehicle comprising the steps of:

(a) monitoring the state of charge of the battery;

(b) determining whether the state of charge of the battery is above or below some predetermined charge level;

(c) maintaining the output produced by the battery charging device at a first voltage level and a charging current when the state of charge of the battery is below the predetermined charge level and at a second voltage level when the state of charge is above the predetermined charge level, the second voltage level being lower than the first level;

(d) monitoring the speed of the vehicle;

(e) determining whether or not the vehicle is decelerating; and

wherein the maintaining step (c) further comprises maintaining the voltage produced by the battery charging device at the first voltage level when the state of charge of the battery is below the predetermined charge level or when the vehicle is decelerating and at the second voltage level when the state of charge is above the predetermined charge level and the vehicle is not decelerating.

20. In an automotive vehicle having a battery and a battery charging device having an output voltage for charging the battery, a system for controlling the charging voltage level applied to the battery comprising:

a first circuit for comparing the charging voltage applied to the battery to a selectable reference voltage level and regulating the battery charging voltage at the reference voltage level;

a device for monitoring the deceleration of the automotive vehicle;

a second circuit for monitoring the amplitude and polarity of current load on the battery;

a third circuit for adjusting the first circuit to increase the charging voltage applied to the battery above the reference voltage level for charging the battery when the vehicle is decelerating or when the load current is above a predetermined load amplitude.

21. The system of claim 20 wherein the device for monitoring deceleration further comprises a circuit for providing a voltage signal corresponding to the speed of the automotive vehicle.

22. The system of claim 21 wherein the provided voltage signal has a duty cycle which varies with the speed of the automotive vehicle.

23. The system of claim 20 further comprising a fourth circuit for sensing the magnitude of the deceleration wherein the third circuit adjusts the first circuit to increase the charging voltage applied to the battery in response to the magnitude of the sensed deceleration.

24. The system of claim 20 wherein the reference voltage level is less than the voltage capacity of the battery at full charge and the increased charging voltage charges the battery.

25. The system of claim 20 wherein the device for monitoring deceleration further comprises an accelerometer circuit having an output voltage that varies in response to the amplitude and polarity of the acceleration of the vehicle.

26. The system of claim 25 wherein the accelerometer circuit further comprises a pendulum movable in a range in a plane in the direction of travel of the vehicle and a circuit having a voltage signal output that varies in response to the position of the pendulum in the range.

27. In an automotive vehicle having a battery and a battery charging device having an output voltage for charging the battery, a method of controlling the charging voltage level applied to the battery comprising:

comparing the charging voltage applied to the battery to a selectable reference voltage level;

regulating the battery charging voltage at the reference voltage level;

monitoring the deceleration of the automotive vehicle;

monitoring the amplitude and polarity of current load on the battery;

increasing the charging voltage applied to the battery above the reference voltage level for charging the battery when the vehicle is decelerating or when the load current is above a predetermined load amplitude.

28. The method of claim 27 in which the step of monitoring deceleration further comprises sensing a voltage signal corresponding to the speed of the automotive vehicle.

29. The method of claim 28 wherein the voltage signal has a duty cycle which varies in relation to the speed of the automotive vehicle.

30. The method of claim 27 further comprising sensing the magnitude of the deceleration and in which the step of increasing the charging voltage further comprises increasing the charging voltage level applied to the battery in response to the magnitude of the sensed deceleration.

31. The method of claim 27 in which the step of monitoring deceleration further comprises providing an accelerometer circuit having an output voltage that varies in response to the amplitude and polarity of the acceleration of the vehicle and identifying the output of the accelerometer circuit corresponding to deceleration.

32. The method of claim 31 wherein the accelerometer circuit further comprises a pendulum movable in a range in a plane in the direction of travel of the vehicle and a circuit having a voltage signal output that varies in response to the position of the pendulum in the range.