US 8,505,370 B2 · Method and system to diagnose exhaust gas sensor deterioration

Abstract

In a method and system to diagnose exhaust gas sensor deterioration, an automobile includes an exhaust gas system. The exhaust gas system has a fuel delivery system, an engine, a catalytic converter, an exhaust gas sensor, a processor, and/or a memory. The fuel delivery system supplies fuel which is combined with air to form a mixture combusted by the engine to generate exhaust. The processor controls the air-fuel ratio of the mixture based on the air-fuel ratio data of the exhaust detected by the exhaust gas sensor. The catalytic converter reduces pollutants in the exhaust. The processor analyzes the air-fuel ratio data to determine one or more time constants of a step response for rich to lean fuel operations and/or lean to rich fuel operations. The processor compares the time constants to a predetermined time constant threshold to determine if the exhaust gas sensor has malfunctioned.

Claims19

Dependent claims

A method for determining whether an exhaust gas sensor has malfunctioned, the method comprising:

detecting, using the exhaust gas sensor, air-fuel ratio data of an exhaust of an engine, the air-fuel ratio data including a starting air-fuel ratio and an actual air-fuel ratio;
determining, using a processor, a time constant of a step response for the exhaust gas sensor from the air-fuel ratio data, the time constant being determined based on a difference between a target air-fuel ratio and the actual air-fuel ratio and a difference between the target air-fuel ratio and the starting air-fuel ratio;
and
comparing, using the processor, the time constant with a predetermined time constant threshold, and determining that the exhaust gas sensor has malfunctioned when the time constant is less than the predetermined time constant threshold.

1 more element

A method for determining an exhaust gas sensor malfunction comprising:

generating, using a fuel delivery unit, a plurality of output cycles of an engine;
detecting, using an exhaust gas sensor, air-fuel ratio data of an exhaust of the engine, the air-fuel ratio data including a starting air-fuel ratio, and an actual air-fuel ratio;
determining, using a processor, a time constant of a step response for the exhaust gas sensor from the air-fuel ratio data, wherein the time constant is determined using a difference between a target air-fuel ratio and the actual air-fuel ratio divided by a difference between the target air-fuel ratio and the starting air-fuel ratio;
and
comparing, using the processor, the time constant with a predetermined time constant threshold, and determining that the exhaust gas sensor has malfunctioned when the time constant is less than the predetermined time constant threshold.

2 more elements

An automobile comprising:

an engine generating an exhaust;
a fuel delivery unit connected to the engine and configured to generate a plurality of output cycles of the engine;
an exhaust gas sensor configured to detect air-fuel ratio data of the exhaust, the air-fuel ratio data including a starting air-fuel ratio, and an actual air-fuel ratio;
and
a processor receiving the air-fuel ratio data and configured to:
determine a time constant of a step response for the exhaust gas sensor from the air-fuel ratio data, wherein the time constant is determined using a difference between a target air-fuel ratio and the actual air-fuel ratio divided by a difference between the target air-fuel ratio and the starting air-fuel ratio,
compare the time constant with a predetermined time constant threshold, and
determine that the exhaust gas sensor has malfunctioned when the time constant is less than the predetermined time constant threshold.

5 more elements

Dependencies are inferred from the claim text.

Method and system to diagnose exhaust gas sensor deterioration

Life of this patent

Method and system to diagnose exhaust gas sensor deterioration

Life of this patent

Abstract

Claims19