# US 10,871,118 B2 · Systems and methods for reducing a light-off time of an oxygen sensor

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- Number: US 10,871,118 B2
- Document ID: US10871118B2
- Status: Granted
- Kind: B2
- Application number: 15/811,085
- Filed: 2017-11-13
- Published: 2019-05-16
- Granted: 2020-12-22
- Earliest claimed: 2017-11-13
- Assignees: Ford Global Technologies, LLC
- Applicants: Ford Global Technologies, LLC
- Inventors: Gopichandra Surnilla; Hao Zhang; Richard E. Soltis; William Russell Goodwin; Robert F. Novak; David Bilby; Evangelos P. Skoures
- Web page: https://patentgrep.com/patent/US10871118B2

## CPC

- F02D 41/1494: {Control of sensor heater}
- F02D 41/1446: {the characteristics being exhaust temperatures}
- F02D 41/064: {at cold start (F02D41/067 takes precedence)}
- F02D 41/1482: {Integrator, i.e. variable slope}
- F02D 41/1483: {Proportional component}
- F02D 2041/141: {using a feed-forward control element}
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

Methods and systems are provided for an oxygen sensor heater. In one example, a method may include applying a less than maximum duty cycle of voltage to the oxygen sensor heater during an engine cold start (e.g., when a temperature of the oxygen sensor is less than its light-off temperature) and adjusting the applied duty cycle of voltage to maintain a constant amount of power. In this way, the oxygen sensor may be heated at a constant rate even as a resistance of the oxygen sensor heater increases, decreasing an amount of time before the oxygen sensor reaches its light-off temperature.

## Claims

### Claim 1

An oxygen sensor heater control method, comprising:
providing a single power value to an oxygen sensor heater included in an oxygen sensor immediately following an indication to start an engine, even as a resistance of the oxygen sensor heater changes with temperature, until a temperature of the oxygen sensor reaches a predetermined operating temperature, where providing the single power value includes increasing an amount of voltage supplied to the oxygen sensor heater over time without decreasing the amount of voltage supplied to the oxygen sensor heater until the temperature of the oxygen sensor reaches the predetermined operating temperature.

### Claim 2 (depends on 1)

The method of claim 1, wherein the predetermined operating temperature is a light-off temperature of the oxygen sensor at or above which an output current of the oxygen sensor is proportionate to a concentration of oxygen sensed via the oxygen sensor.

### Claim 3 (depends on 2)

The method of claim 2, wherein providing the single power value raises the temperature of the oxygen sensor to the predetermined operating temperature at a constant rate.

### Claim 4 (depends on 3)

The method of claim 3, wherein the single power value is based on a heat capacity of the oxygen sensor.

### Claim 5 (depends on 4)

The method of claim 4, wherein the single power value is further based on the constant rate and heat loss of the oxygen sensor while the oxygen sensor is heated to the predetermined operating temperature.

### Claim 6 (depends on 5)

The method of claim 5, wherein the heat loss of the oxygen sensor includes heat transferred to exhaust gas through convection.

### Claim 7 (depends on 1)

The method of claim 1, further comprising, after the temperature of the oxygen sensor reaches the predetermined operating temperature, providing a varying power value to the oxygen sensor heater to maintain the temperature of the oxygen sensor at or above the predetermined operating temperature.