Series parallel heated oxygen sensor heater control

• US 5,637,786 A
• Filed: 07/05/1995
• Issued: 06/10/1997
• Est. Priority Date: 07/05/1995
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Weber, David C., Rooke, Alan M.
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US08/498,193
• Time in Patent Office: 706 Days
• Field of Search: 73/23.31, 73/23.32, 73/116, 73/117.2, 73/117.3, 73/118.1, 123/697
• US Class Current: 73/23.32
• CPC Class Codes: G01N 27/4067 Means for heating or controlling the temperature of the solid electrolyte

Abstract

This invention teaches a series parallel heated oxygen sensor control wherein a parallel portion is used to apply heat to the oxygen sensor during warm-up and a series portion is used to apply heat to the oxygen sensor afterwards so that about one quarter of the amount of power is applied after warm-up.

Claims

1. A circuit for applying power to multiple heaters of a heated exhaust gas oxygen sensor including:

a first parallel configuration of multiple heaters;

a serial configuration that reduces the power in a heater to 1/4 that of said first parallel configuration; and

further including a switching means to change the coupling of the said multiple heaters from the parallel to the serial configuration.

2. A circuit as recited in claim 1 further comprising a sensing resistor in each of the two branches of the first parallel circuit for sensing the amount of current flowing through the heated exhaust gas oxygen sensor.