Vehicle electrical system

• US 6,690,140 B2
• Filed: 08/30/2001
• Issued: 02/10/2004
• Est. Priority Date: 08/30/2001
• Status: Expired due to Fees

• Current Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Original Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Inventors: Larson, Gerald L.
• Primary Examiner(s): Tibbits, Pia
• Application Number:
  US09/945,473
• Publication Number:
  US 20030042872A1
• Time in Patent Office: 894 Days
• Field of Search: 320/104, 320/137, 320/150, 320/152, 320/154, 320/167, 307/9, 307/10.1, 307/18, 307/64, 307/65, 307/66, 307/67, 322/28, 322/90, 429/61, 429/62
• US Class Current: 320/104
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A vehicle electrical system is disclosed having a plurality of electrical subsystems for supplying power to different component groups of the vehicle. A voltage regulator is provided each subsystem for setting the voltage on each electrical subsystem independently of the other electrical subsystems. One such subsystem includes a battery having a grounded terminal and an ungrounded terminal. An electrical system controller including data processing capacity provides control of the voltage level on the charging subsystem through a charging regulator having an output connected to the ungrounded terminal of the battery and a control input. An electrical power generator is connected to energize the charging regulator. Instrumentation connected to the electrical system controller provides measurements of current discharged from the battery, current delivered to the battery, and battery temperature. A program residing on the electrical system controller for execution, utilizes battery temperature, battery temperature rate of change and measured current discharged as inputs to an algorithm for dynamically setting a control signal value. The generated control signal is applied to the control input of the charging regulator.

Claims

1. A vehicle electrical system, comprising:

an alternator;

a plurality of subsidiary electrical systems operating at different voltage levels coupled to the alternator for energization, at least two of the subsidiary electrical systems, each subsidiary electrical system having a voltage regulator isolating the voltage levels on said subsidiary electrical system from the other subsidiary electrical system;

one of said at least two subsidiary electrical systems being a battery charging system with the voltage regulator for the battery chaining system being a controllable voltage regulator coupled to the alternator for energization;

a battery in the battery charging system connected to the controllable voltage regulator for receiving charging current;

a battery temperature sensor providing measurement signals of battery temperature;

a current sensor coupled to a terminal of the battery for providing signals relating to current drawn and supplied to the battery; and

a body controller computer connected to receive the measurement signals of battery temperature and the signals relating to current drawn and supplied to the battery and responsive thereto for generating a control signal for regulating the output voltage of the battery charging current provided by the controllable voltage regulator.

2. A vehicle electrical system as set fort in claim 1, one of the subsidiary electrical systems comprising:

a low voltage system having a low voltage regulator connected to the alternator for energization.

3. A vehicle electrical system as set forth in claim 2, further comprising a high voltage subsidiary electrical system having a high voltage regulator.

4. A vehicle electrical system as set forth in claim 3, further comprising:

the body controller computer including programming for determining the current discharged from the battery during starting in response to measurements of current drawn; and

the body controller computer being further programmed for generating the control signal applied to the controllable voltage regulator.

5. A vehicle electrical system as set forth in claim 4, further comprising a first battery being charged at first voltage and a second battery charged at a second voltage.

6. A vehicle electrical system, comprising:

a first lead acid battery having at least two terminals;

a current sensor coupled to a terminal of the first lead acid battery for measuring current sourced from and delivered to the first lead acid battery;

a temperature sensor proximate to the first lead acid battery for measuring battery temperature;

a controllable voltage regulator responsive to a control signal for controlling current delivered to the first lead acid battery and having input and output terminals, connected by the output terminal to the terminal of the first lead acid battery to which the current sensor is coupled;

a low voltage system including lighting having a voltage regulator with an input;

a body controller computer responsive to the measured current sourced from the first lead acid battery and the measured battery temperature for generating the control signal applied to the charging regulator; and

an alternator connected to the inputs of the controllable voltage regulator and the voltage regulator.

7. A vehicle electrical system as set forth in claim 6, further comprising a second lead acid battery, the first lead acid battery and second lead acid battery being charged at first and second voltage levels, respectively, the controllable regulator providing charging currents at said first and second voltage levels to the first and second lead acid batteries.

8. A vehicle electrical system as set forth in claim 7, wherein the body controller computer is further programmed;

for estimating battery internal resistance;

for estimating battery internal losses during charging; and

to be responsive to estimated internal losses of the batteries for adjusting the control signals applied to the controllable voltage regulator.