CHARGE CONTROL SYSTEM

• US 20110215764A1
• Filed: 03/03/2011
• Published: 09/08/2011
• Est. Priority Date: 03/05/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: TAKAHASHI, Shin, MAEDA, Shunichi
• Granted Patent: US 8,686,692 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02J 7/1446 in response to parameters of a vehicle

Abstract

An in-vehicle charge control system includes a vehicle-state detector that detects a running state of a vehicle, a battery-state detector that detects a charge level of an in-vehicle battery, a fuel-efficiency-enhancement controller that predicts a discharge amount to be discharged by the battery under a discharge condition, sets a lower limit of the battery charge level on the basis of the battery charge level detected by the detector such that the lower limit of the battery charge level is higher than a battery charge level at which the battery begins to degrade by the predicted discharge amount, and controls a power generation amount of a vehicle generator according to the vehicle state detected by the detector. The system with this configuration can maintain the battery charge level and enhance the fuel efficiency simultaneously under practical use conditions.

Claims

1. A charge control system comprising:

vehicle-state detection means for detecting a running state of a vehicle;

battery-state detection means for detecting a charge level of an in-vehicle battery;

power generation control means for predicting a discharge amount to be discharged by the battery under a discharge condition, setting a lower limit of the battery charge level on the basis of the battery charge level detected by the battery-state detection means such that the lower limit of the battery charge level is higher than a battery charge level at which the battery begins to degrade by the predicted discharge amount, and controlling a power generation amount of a vehicle generator according to the vehicle state detected by the vehicle-state detection means.

2. The system of claim 1, wherein the power generation control means instructs the vehicle generator to perform regenerative power generation when the vehicle running state detected by the vehicle-state detection means indicates a deceleration state of the vehicle, and modifies the lower limit of the battery charge level taking in account a charge amount to be generated by the regenerative power generation.

3. The system of claim 1, wherein the discharge condition is a condition that a rotation speed of the vehicle generator is equal to or lower than a specific rotation speed at which a load current value is equally balanced with a maximum power generation amount of the vehicle generator.

4. The system of claim 1, wherein the discharge condition is a condition that the vehicle is idling.

5. The system of claim 1, wherein the discharge amount is predicted by subtracting a maximum power generation amount of the vehicle generator under the discharge condition from a load current value and then multiplying the resultant value by a predicted discharge time.

6. The system of claim 5, further comprising load-state detection means for detecting a load current that flows through an electrical load connected to the in-vehicle battery.

7. The system of claim 6, wherein the load-state detection means uses, as the load current, the discharging current of the battery during power generation of the vehicle generator being stopped.

8. The system of claim 5, wherein the predicted discharge time is set to a predetermined time period defined according to an envisaged running state of the vehicle.

9. The system of claim 5, wherein the predicted discharge time is set to an average time period taken over a plurality of past discharge durations.

10. A method of controlling charging operations for an in-vehicle battery, the method comprising steps:

detecting a running state of a vehicle;

detecting a charge level of the battery;

predicting a discharge amount to be discharged by the battery under a discharge condition;

setting a lower limit of the battery charge level on the basis of the detected battery charge level such that the lower limit of the battery charge level is higher than a battery charge level at which the battery begins to degrade by the predicted discharge amount; and

controlling a power generation amount of a vehicle generator according to the detected vehicle state.