Mark H. Costin

Model-based on-board fault detection and diagnosis for automotive engines☆

Abstract This paper desribes an algorithm developed for the online detection and diagnosis of faults in automobile engine sensors and actuators, using the on-board microcomputer. The algorithm is based on the structured parity equation methodology. The parity equations are derived from an engine model having linear dynamics and static nonlinearities, obtained by identification from simualtion experiments.

On-Board Diagnostics of Vehicle Emission System Components: Review of Upcoming Government Regulation

Abstract This paper reviews the upcoming California Air Resources Board (CARB) requirements for on-board diagnostics of emissions related engine components. Its purpose is to disseminate this information to the controls community to stimulate new research. The CARB regulations are described and a literature review of possible solutions is presented. The state-of-the-art for current on-board engine diagnostics is reviewed and the desired characteristics of new on-board failure detection systems are outlined. This paper closes with a short review of advanced diagnostic techniques that show promise for resolving problems in this area.

Model-based On-Board Fault Detection and Diagnosis for Automotive Engines

Abstract This paper desribes an algorithm developed for the online detection and diagnosis of faults in automobile engine sensors and actuators, using the on-board microcomputer. The algorithm is based on the structured parity equation methodology. The parity equations are derived from an engine model having linear dynamics and static nonlinearities, obtained by identification from simualtion experiments.

Direct Identification of Structured Parity Equations

Abstract Structured parity equations are transformed input-output relations shaped to provide characteristic structures in response to specific faults. To construct them, the knowledge of the system model is needed. It is shown in this paper how the parameters of parity equations can be obtained by direct identification, whether they describe a system input-output relation, a physical unit model or a relation resulting from pure mathematical manipulations. It is also shown how valid parity equations can be obtained if the data has been collected under closed-loop control and therefore the inputs are linearly related.

Model-Based Diagnosis of Automotive Engines: Case Study on a Physical Vehicle

Abstract Some results and lessons of a four year project, aimed at demonstrating the feasibility of model based diagnosis of automobile engines, are summarized. A production vehicle, arbitrarily picked from the manufacturers lot, has been used, with standard measurement and control devices. The diagnostic approach was the technique of structured parity equations. The algorithm has been implemented, on hardware equivalent to the production devices, both in on-board and in service versions. The paper describes the extensive data collection, model identification, algorithm development and system validation effort. The project has demonstrated the feasibility of this technology on a single production vehicle though the achievable fault sensitivities have been found to be limited by unmodeled effects. Open issues include car-to-car variations and long-term behavior.

An Encoding Scheme for Reporting Sensor Signal Values

This paper presents a novel encoding scheme as an alternative to Analog amplitude encoding for communicating sensor signals. The scheme has the potential of becoming a non-proprietary industrial standard for communicating sensor information to electronic control modules. Key features of the encoding scheme are the ability to communicate two sensor values using only 3 wires (power, ground and signal) with 12 bit resolution within 1ms. The scheme includes a checksum for error detection and a mechanism for reporting serial data such as low rate sensor information, part numbers or fault codes. Data is communicated to the receiving module by varying the time between discrete (single edge polarity) transitions. The encoding is self-calibrating and does not require an expensive crystal in the sending module (assumed to be a low-cost ASIC) to maintain signal integrity.

MODEL-BASED ON-BOARD FAULT DETECTION AND DIAGNOSIS FOR AUTOMOTIVE ENGINES

This paper desribes an algorithm developed for the online detection and diagnosis of faults in automobile engine sensors and actuators, using the on-board microcomputer. The algorithm is based on the structured parity equation methodology. The parity equations are derived from an engine model having linear dynamics and static nonlinearities, obtained by identification from simualtion experiments.