DUAL BATTERY ELECTRICAL SYSTEM FOR INTERNAL COMBUSTION ENGINE

• US 3,816,805 A
• Filed: 05/16/1973
• Issued: 06/11/1974
• Est. Priority Date: 05/16/1973
• Status: Expired due to Term

• Current Assignee: Stanley M. Terry
• Original Assignee: Stanley M. Terry
• Inventors: Terry, Stanley M.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/360,908
• Time in Patent Office: 391 Days
• Field of Search: 320/15,17,18,6,14 322/90 307/16
• US Class Current: 320/123
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: H02J 7/1423 with multiple batteries

Abstract

In a dual battery system for an internal combustion engine, as used in a vehicle or the like, wherein an auxiliary battery is connected in series with a service battery to provide a high battery voltage for a starter circuit, a charging means is provided for charging both the service battery and the auxiliary battery without changing their series connection. This charging means comprises an alternator, rectifier and voltage regulator for charging the service battery and an additional rectifier connected to the alternator through an isolation transformer for charging the auxiliary battery.

Claims

1. An electrical system associated with an internal combustion engine, said system comprising:

a service battery and an auxiliary battery each having two terminals of opposite polarity, said service battery having one of its terminals directly connected to one of said terminals of said auxiliary battery with said two directly connected terminals of said two batteries being of opposite polarity so that said two batteries form a series connected combination of two batteries, a starter motor circuit connected across said series combination of two batteries, a service load circuit connected across said service battery, an alternator, a first rectifier arranged to rectify the output of said alternator and to apply its rectified output across said service battery, a second rectifier, and an isolation transformer connected between said second rectifier and said alternator for supplying said second rectifier with power from said alternator, said second rectifier having a pair of output terminals connected across said auxiliary battery.

2. An electrical system as defined in claim 1 further characterized by said alternator including a field winding, and a voltage regulator responsive to the voltage across said service battery for controlling the energization of said field winding so as to maintain the voltage across said service battery substantially constant.

3. An electrical system as defined in claim 2 further characterized by said alternator being a three-phase alternator, said first rectifier being a three-phase rectifier and having all three phases of said alternator as an input thereto, and said second rectifier being a single phase rectifier and having only one phase of said alternator as an input thereto.

4. An electrical system as defined in claim 3 further characterized by a series resistance connected between said second rectifier and said auxiliary battery.

5. An electrical system as defined in claim 3 further characterized by said service battery and said auxiliary battery both having substantially the same voltage rating and said isolation transformer having a transformer ratio of approximately 1.3.

6. An electrical system associated with an internal combustion engine, said system comprising:

first, second and third terminals, a service battery connected between said first and second terminals, an auxiliary battery connected between said second and third terminals, a starter motor circuit connected across said first and third terminals, a service load circuit connected across said first and second terminals, a polyphase alternator having an output consisting of a plurality of generally similar voltage waveforms phase displaced from one another, a polyphase rectifier having two output terminals, said polyphase rectifier being connected with said polyphase alternator so as to have as an input thereto all of said output voltage waveforms of said alternator and being operable to convert said output voltage waveforms of said alternator into a rectified voltage appearing across said two output terminals thereof, means connecting said two output terminals of said polyphase rectifier respectively to said first and second terminals, an isolation transformer having primary and secondary windings, means connecting said primary winding of said isolation transformer to said polyphase alternator so that one of said output voltage waveforms of said alternator is applied across said primary winding, a single phase rectifier having two input terminals and two output terminals, means connecting said secondary winding of said isolation transformer across said two input terminals of said single phase rectifier, and means connecting said two output terminals of said single phase rectifier respectively to said second and third terminals.

7. An electrical system as defined in claim 6 further characterized by a voltage regulator connected with said alternator and with said first and second terminals and operable to vary the excitation of said alternator so as to maintain a substantially constant voltage between said first and second terminals.

8. An electrical system as defined in claim 6 further characterized by said first terminal being a ground terminal.

9. An electrical system as defined in claim 6 further characterized by said service battery and said auxiliary battery both having substantially the same voltage rating, and said isolation transformer having a transformer ratio such that the average voltage appearing across said two output terminals of said single phase rectifier is approximately equal to the average voltage appearing across said two output terminals of said polyphase rectifier.

10. An electrical system as defined in claim 6 further characterized by said polyphase alternator being a three-phase alternator having three output terminals, and said polyphase rectifier being a three-phase bridge rectifier having three input terminals connected respectively to said three output terminals of said alternator, said primary winding of said isolation transformer being connected to said alternator by being connected across two of said output terminals of said alternator.

11. An electrical system as defined in claim 10 further characterized by said service battery and said auxiliary battery both having substantially the same voltage rating, and said transformer having a transformer ratio of approximately 1.3.

12. An electrical system as defined in claim 6 further characterized by a resistor, one of said output terminals of said single phase rectifier being connected to its associated one of said second and third terminals through said resistor.

13. An electrical system as defined in claim 6 further characterized by a circuit breaker device, one of said output terminals of said single phase rectifier being connected to its associated one of said second and third terminals through said circuit breaker device.

14. An electrical system as defined in claim 7 further characterized by said alternator having a plurality of generating windings in which said output voltage waveforms are generated and a field winding the excitation of which controls the amount of power generated in said generating windings, said voltage regulator including means for varying the excitation of said field winding in response to changes in the voltage between said first and second terMinals so as to maintain said latter voltage at a substantially constant value.