Dual-voltage control for an electrical load

• US 5,661,368 A
• Filed: 09/25/1995
• Issued: 08/26/1997
• Est. Priority Date: 09/25/1995
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Nasser, Ahmad Mustapha, Deol, Satvir Singh, Bush, Thomas Alexander
• Primary Examiner(s): Lee, Benny
• Assistant Examiner(s): SHINGLETON, MICHAEL B
• Application Number:
  US08/533,569
• Time in Patent Office: 701 Days
• Field of Search: 315/82, 315/137, 315/147, 307/10.8
• US Class Current: 315/82
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00

Abstract

In one embodiment of the present invention, a daytime running lamp (DRL) system for a motor vehicle includes a switchable connection from the headlamps of the vehicle to the neutral connection of the vehicle'"'"'s alternator. Compared with the full system voltage of the vehicle, the neutral connection of the alternator is a lower-voltage source which can drive the headlamps at reduced brightness. Such reduced brightness is a typical characteristic of DRL systems. The system disclosed herein can be more cost-effective and provide greater energy efficiency than alternative DRL systems.

Claims

1. An electrical system comprising:

a polyphase alternator having a neutral connection and having an output with an average voltage greater than an average voltage at said neutral connection;

an electrical load;

first switching means for switchably coupling and decoupling said electrical load to said output of said alternator;

second switching means responsive to said first switching means for coupling said neutral connection of said alternator to said electrical load if said output of said alternator is decoupled from said electrical load by said first switching means;

a parking brake switch; and

third switching means responsive to said parking brake switch for coupling and decoupling said electrical load to said neutral connection in response to positions of said parking brake switch;

wherein

said electrical load is a headlamp of a motor vehicle.

2. An electrical system as recited in claim 1, wherein said first switching means comprises a high-current headlamp switch.

3. A method for controlling an electrical system comprising an electrical load adapted to be coupled and decoupled from a first voltage, said method comprising:

coupling said electrical load to a neutral connection of a polyphase alternator in response to said electrical load being decoupled from said first voltage; and

coupling and decoupling said electrical load from said neutral connection of said alternator in response to a position of a parking brake switch;

wherein said electrical load is a headlamp.

4. An electrical system comprising:

a polyphase alternator having a neutral connection and an output having an average voltage greater than an average voltage at said neutral connection;

at least one headlamp;

a headlamp switch connected between said output of said alternator and said headlamp and adapted to switchably couple and decouple said output of said alternator to and from said at least one headlamp;

a first relay having a contact responsive to said headlamp switch such that said contact couples said neutral connection of said alternator to said headlamp when said headlamp switch decouples said output of said alternator from said headlamp;

a parking brake switch; and

a second relay having a contact responsive to a position of said parking brake switch and in series with said contact of said first relay.