Rough road detection system used in an on-board diagnostic system
First Claim
Patent Images
1. A method to reduce false positive error determinations from a diagnostic component in a vehicle traveling on a road, comprising:
- receiving input signals from wheel speed sensors;
determining changes of the input signals using a high pass filter so that output signals from the high pass filter indicate a current magnitude of external roughness of a road surface;
processing the output signals from the high pass filter using a rolling average filter so that a roughness level is determined over a predetermined time interval;
comparing output signals from the rolling average filter to a predetermined threshold; and
disabling an error output of the diagnostic component if the roughness level has exceeded the predetermined threshold.
1 Assignment
0 Petitions
Accused Products
Abstract
An on-board diagnostic system of a vehicle comprises disabling diagnostic operation, such as a misfire monitor, based on road roughness. In one example, the disabling of the diagnostic operation is based on brake actuation and degradation of an anti-lock braking system.
36 Citations
7 Claims
-
1. A method to reduce false positive error determinations from a diagnostic component in a vehicle traveling on a road, comprising:
-
receiving input signals from wheel speed sensors; determining changes of the input signals using a high pass filter so that output signals from the high pass filter indicate a current magnitude of external roughness of a road surface; processing the output signals from the high pass filter using a rolling average filter so that a roughness level is determined over a predetermined time interval; comparing output signals from the rolling average filter to a predetermined threshold; and disabling an error output of the diagnostic component if the roughness level has exceeded the predetermined threshold. - View Dependent Claims (2, 3, 4)
-
-
5. A method to reduce false positive error determinations, comprising:
-
monitoring engine misfire conditions; disabling an engine misfire monitoring error output in response to an average level of road roughness above a threshold the average level of road roughness based on high-pass filtered wheel speed sensor data; and suspending the disabling in response to wheel brake actuation and suspending the disabling in response to degradation of an anti-lock brake system. - View Dependent Claims (6, 7)
-
Specification