Electrical system for a vehicle with start/stop

Patent metadata

Field	Value
Publication number	US-9752547-B2
Application number	US-201213527204-A
Country	US
Kind code	B2
Filing date	Jun 19, 2012
Priority date	Jun 22, 2011
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

An electrical system for a vehicle having an internal combustion engine with start/stop capability includes a primary battery connectible to an engine starter motor; a secondary battery, an alternator, and an electrical load in parallel with one another and selectively connectible in parallel with the primary battery by a charge switch; in parallel with the secondary battery, a DC/DC converter in series with a third electrical energy source; and a bypass switch operable to selectively bypass the DC/DC converter. The bypass switch allows for selective bypassing the DC/DC converter and charging/discharging of the third electrical energy source during start/stop operation, to ensure a sufficient voltage level over the additional vehicle electrical loads when the internal combustion engine and consequently the alternator are not running.

First claim

What is claimed is:

1. A method for operating an electrical system of a vehicle having an internal combustion engine provided with a start/stop system enabling shutoff of the internal combustion engine while electrical systems of the vehicle are running, the electrical system further comprising a primary battery selectively connectible to a starter motor for the internal combustion engine via a starter solenoid, a secondary battery, an alternator, and additional vehicle electrical loads arranged in parallel with one another and selectively connectible in parallel with the primary battery via a charge switch, the method comprising:
arranging in parallel with the secondary battery a DC/DC converter in series with a third electrical energy source;
and providing a bypass switch for selectively bypassing the DC/DC converter.

2. The method of claim 1 , further comprising arranging as the third electrical energy source a super-capacitor.

3. The method of claim 1 , further comprising arranging as the third electrical energy source a lithium-ion battery.

4. The method of claim 1 , wherein when the engine is stopped during a start/stop event the electrical system is operated such that:
the charge switch is open;
the bypass switch is open; and
the DC/DC converter is boosting.

5. The method of claim 1 wherein to achieve a cold-start of the engine the electrical system is operated such that:
the starter solenoid is closed to supply power to the starter motor;
the charge switch is open;
the bypass switch is open; and
the DC/DC converter is off.

6. A method of operation of a motor vehicle, the vehicle having an internal combustion engine operable in a start/stop mode enabling shutoff of the internal combustion engine while electrical systems of the vehicle are running, and an electrical system including a primary battery selectively connectible to a starter motor for the internal combustion engine via a starter solenoid; a secondary battery, an alternator, and additional vehicle electrical loads arranged in parallel with one another and selectively connectible in parallel with the primary battery via a charge switch; and, in parallel with the secondary battery, a DC/DC converter and associated bypass switch in series with a third electrical energy source, the method of operation comprising:
when the engine is stopped during a start/stop event:
the charge switch is open, the bypass switch is open, and the DC/DC converter is boosting; and
during a warm-start of the engine after a start/stop event:
the starter solenoid is closed to supply power to the starter motor, the charge switch is open, the bypass switch is open, and the DC/DC converter is off.

7. The method of claim 6 further comprising:
during a cold-start of the engine:
the starter solenoid is closed to supply power to the starter motor, the charge switch is open, the bypass switch is open, and the DC/DC converter is off.

8. The method of claim 6 further comprising:
when the engine is running after either a warm-start or a cold-start:
the charge switch is closed, the bypass switch is closed, and the DC/DC converter is off.

9. The method of claim 6 further comprising:
when the vehicle is in a state of long-term parking:
the charge switch is open, the bypass switch is open, and the DC/DC converter is off.

Assignees

• Spjuth Oerjan
• Larsson Torbjoern
• Midholm Daniel
• Ulmhage Fredrik
• Volvo Car Corp

Inventors

• Spjuth Oerjan
• Larsson Torbjoern
• Midholm Daniel
• Ulmhage Fredrik

Classifications

• F02N2250/02

  Battery voltage drop at start, e.g. drops causing ECU reset · CPC title

• F02N2011/0888

  DC/DC converters · CPC title

• F02N11/0866 Primary

  comprising several power sources, e.g. battery and capacitor or two batteries · CPC title

• F02N2011/0885

  Capacitors, e.g. for additional power supply · CPC title