On-board Diagnosis Research Articles

NEURAL NETWORK APPLICATIONS FOR MODEL BASED FAULT DETECTION WITH PARITY EQUATIONS

The rising complexity of modern automotive engines with an increasing number of actuators and sensors to minimise emissions and fuel consumption and to maximise engine driveability require a detailed supervision for fault detection and on-board diagnosis. The European Community Directive 98/69/EC requires on-board diagnosis for spark ignition engines and will require it for diesel engines as of January 2003, mainly to prevent excessive emissions. Beside this regulation it is also in the interest of the automobile manufactures to establish capable diagnosis systems for maintenance, repair and the benefit of their customers. This paper will describe applications of neural networks for modelling complex fluid- and thermodynamics with unknown physical model structure. Reference models, which describe the fault free process, are set up and identified with the special neural network LOLIMOT (Local-Linear-Model-Tree). Fault detection algorithms, which employ the method of parity equations, were successfully implemented and tested in real time with a 2 litre diesel engine and a Rapid Control Prototyping System. Measurements of online fault detection are shown for several built-in faults in the intake system of this diesel engine.

Confidence Level Analysis for On-Board Estimation of SI Engine Catalytic Converter Efficiency

For the on-board diagnosis of the catalytic converter for SI engine, the comparison between upstream and downstream catalyst lambda signals is used to derive information about the actual conversion efficiency. In the present work three indices have been computed by means of both deterministic and statistical approaches, allowing to perform confidence analysis concerning the estimation of catalyst efficiency. The proposed approaches have been applied to process experimental data measured during New European Driving Cycle (ECE+EUDC) and to estimate the probability of fault occurrence during intermediate aged catalyst status. Furthermore, the three indices have been compared with respect to the risk levels associated with both undetected catalyst faults and false alarms.

Fast Chemical Sensors for Emission Control

Consideration of environmental issues is constantly growing. This brings about a potential market for more sophisticated control of emissions from automobiles and more advanced on-board diagnosis. There is also a growing interest in zero emission power plants and in stricter regulation of other emission sources in industry. One of the important prerequisites for this development is the existence of reliable chemical sensors for combustion control.

Study on electrically heated catalyst (EHC) system — Part 2: Onboard diagnosis systems (OBD-II) for EHC and secondary air system Yuichi Shimasaki, Hiroaki Kato, Hironao Fukuchi, Akihisa Saito, Takuya Aoki (Honda R & D Co., Ltd.)

Study on electrically heated catalyst (EHC) system — Part 2: Onboard diagnosis systems (OBD-II) for EHC and secondary air system Yuichi Shimasaki, Hiroaki Kato, Hironao Fukuchi, Akihisa Saito, Takuya Aoki (Honda R & D Co., Ltd.)

On-board and real-time expert control

Development of an on board real time expert system for controlling engineering systems requires tradeoffs between AI and real time approaches. The article presents an alternative that lies between embedding AI in real time and embedding real time in AI. We used this framework to develop an expert system development environment for maintaining and updating information about an evolving system as its state changes because of abnormal events such as faults, or as a consequence of external actions taken upon the system. We've successfully applied it in several engineering domains such as process control, medical monitoring, and onboard diagnosis. The author explains how it was applied to a system that controls automobile manoeuvring.

9540264 On-board diagnosis of the three-way catalyst using a correlation method Nobuo Kurihara, Hiroshi Kimura, Toshio Ishii, Yutaka Takaku (Hitachi, Ltd.)

9540264 On-board diagnosis of the three-way catalyst using a correlation method Nobuo Kurihara, Hiroshi Kimura, Toshio Ishii, Yutaka Takaku (Hitachi, Ltd.)

Detection of Automotive Catalysts Failure by Use of On-Board Diagnostics

Although major emission reductions from gasoline vehicles have been achieved with the help of catalytic exhaust gas after-treatment, durability of the systems involved is still difficult to guarantee with high confidence levels. On-board diagnosis (OBD) of the main emission control systems is expected to play a central role in any modern emission reduction policy. An overview of theoretical principles regarding catalytic converter operation characteristics, catalyst activity deterioration and OBD system requirements is initially presented. The most important existing approaches to catalytic converter on-board diagnosis are examined by means of presenting principles of operation, assessment methodologies and practical problems associated with each of them. The techniques examined cover dual lambda sensor, hydrocarbon and temperature measurement methods, some of which have already been applied to conform to transitional OBD regulations. It appears, however, that significant work remains to be carried out in order to develop reliable and cost-effective catalytic converter OBD technology to cover legislation requirements, especially for modern low-emitting vehicles.

On-Board Diagnosis of Engine Faults

On-board diagnosis of faults in automotive components and subsystems has become an important issue for the automotive industry, due to the following reasons: (i) onboard diagnostic capabilities enhance the maintainability and repairability of vehicles; (ii) compliance with increasingly stringent government mandates requiring the reduction of exhaust gas emissions demands on-board diagnostic systems to ensure proper operation of the exhaust gas emissions control system; and (iii) the increasing capabilities of on-board computers and vehicle controllers has made feasible the implementation of more sophisticated diagnostic and control algorithms. The aim of this paper is to present the application of different fault detection methods to internal combustion engine diagnostics. The potential usefulness of the methods is validated experimentally on production engines.

9437395 A state estimation method for exhaust system of gasoline engine: On-board diagnosis of three-way catalyst: Nobuo Kurihara, Masayoshi Kaneyasu, Toshio Ishii (Hitachi, Ltd.), pp. 53–56, 5 figs., 1 ref

9437395 A state estimation method for exhaust system of gasoline engine: On-board diagnosis of three-way catalyst: Nobuo Kurihara, Masayoshi Kaneyasu, Toshio Ishii (Hitachi, Ltd.), pp. 53–56, 5 figs., 1 ref