On-board Diagnosis Research Articles

Comprehensive thermal modeling of a power-split hybrid powertrain using battery cell model

This manuscript discusses the development of a 3D thermal model for a power-split hybrid powertrain, including its battery modules and power electronics. The 3D model utilizes a finite differencing (FD) heat transfer algorithm, complemented with experimental boundary conditions. The experimental setup is configured to acquire the battery current, voltage, and its inner and surface temperatures in discrete and in full-field scans. The power-split hybrid configuration is tested using a standard and artificial driving cycles. A battery resistance model is then used to couple the experimental boundary conditions with the finite differencing code, which employed a cell-based internal heat generation model to describe the pack chemical reaction mechanism. This study presents a complete analysis based on battery current and voltage in relation to vehicle speed. The proposed model also predicts the powertrain spatial and temporal temperature profiles in agreement with the vehicle actual conditions as indicated by the On-Board Diagnosis (OBD) module.

A systematic approach to observer design for the air-intake of combustion engines.

AbstractIn this paper a systematic approach to observer design is presented for the assumption, that the plant model is not available in analytic form but only as a numerical model and that the resulting observer should use minimal computational resources. Both assumptions are frequently met in the field of real time engine management systems. To cope with this assumptions a gain-scheduling design is presented that is based on a numerically computed linearization. It is also presented how such an observer, designed for control optimized performance, can also be used to improve the performance of on-board diagnosis (OBD) in engine management systems.

Comparison of a turbocharger model based on isentropic efficiency maps with a parametric approach based on Euler's turbo-machinery equation

AbstractFaults in the intake and exhaust path of turbocharged common rail Diesel engines can lead to an increase of emissions and performance losses. Application of turbocharger models can help to detect and diagnose more faults as standard fault detection methods. The modeling of the turbocharger for onboard fault diagnosis can be obtained by different models. The differences between an approach based on the isentropic efficiencies and an approach based on Euler's turbo-machinery equation are investigated in this paper. The two models for a GT1749MV turbocharger are parameterized with data from the engine testbed. The comparison is applied by issues of measured model inputs, number of intern parameters, parameterization effort and model accuracy. Both models are compared regarding the application for onboard diagnosis.

Identifying static and dynamic prediction models for NOx emissions with evolving fuzzy systems

Abstract Antipollution legislation in automotive internal combustion engines requires active control and prediction of pollutant formation and emissions. Predictive emission models are of great use in the system calibration phase, and also can be integrated for the engine control and on-board diagnosis tasks. In this paper, fuzzy modelling of the NOx emissions of a diesel engine is investigated, which overcomes some drawbacks of pure engine mapping or analytical physical-oriented models. For building up the fuzzy NOx prediction models, the FLEXFIS approach (short for FLEXible Fuzzy Inference Systems) is applied, which automatically extracts an appropriate number of rules and fuzzy sets by an evolving version of vector quantization ( eVQ) and estimates the consequent parameters of Takagi-Sugeno fuzzy systems with the local learning approach in order to optimize the least squares functional. The predictive power of the fuzzy NOx prediction models is compared with that one achieved by physical-oriented models based on high-dimensional engine data recorded during steady-state and dynamic engine states.

Intrinsic Hurdles in Applying Automated Diagnosis and Recovery to Spacecraft

Experience developing and deploying model-based diagnosis (MBD) and recovery and other model-based technologies on a variety of testbeds and flight experiments led us to explore why our expectations about the impact of MBD on spacecraft operations have not been matched by effective benefits in the field. By MBD, we mean the problem of observing a mechanical, software, or other system and determining what failures its internal components have suffered using a generic inference algorithm and a model of the system's components and interconnections. These techniques are very attractive, suggesting a vision of machines that repair themselves, reduced costs for all kinds of endeavors, spacecraft that continue their missions even when failing, and so on. This promise inspired a broad range of activities, including our involvement over several years in flying the Livingstone and L2 onboard MBD and recovery systems as experiments on Deep Space 1 and Earth Observer 1 spacecraft. Yet, in the end, no spacecraft project adopted the technology in operations nor flew additional flight experiments. To our knowledge, no spacecraft project has adopted any other MBD technology in operations. In this paper, we present a cost/benefit analysis for MBD using expectations and experiences with Livingstone as an example. We provide an overview of common techniques for making spacecraft robust, citing fault protection schemes from recent missions. We lay out the cost, benefit, and risk advantages associated with onboard MBD and use the examples to probe each expected advantage in turn. We suggest a method for evaluating a mission that has already been flown and providing a rough estimate of the maximum value that a perfect onboard diagnosis and recovery system would have provided. By unpacking the events that must occur in order to provide value, we also identify the factors needed to compute the <emphasis emphasistype="italic" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> expected</emphasis> value that would be provided by a real diagnosis and recovery system. We then discuss the expected value we would estimate that such a system would have had for the Mars Exploration Rover mission. This has allowed us to identify the specific assumptions that made our expectations for MBD in this domain incorrect.

オンボード診断のための専用ハードウェアとその設計手法について

オンボード診断のための専用ハードウェアとその設計手法について

Simulation of the dynamics of a marine diesel engine

This paper presents a simulation model of a turbocharged four-stroke diesel engine with eight cylinders in transient conditions, attached to a propulsion system. Having an engine model that is accurate but not complicated is desirable when working with on-board diagnosis or engine control. The model presented here is relatively simple, but sufficiently precise to be able to describe the behaviour of a complete propulsion plant giving as output values the time histories of all variables considered.

On-board diagnosis of the drive circuit of an electronically controlled injector

On-board diagnosis regulations, drive safety, and facility of service require that the engine control unit must detect malfunctions of the electronically controlled fuel injection system. For injector drive circuit faults, there are two types of fault definition in the Society of Automotive Engineers J2012 regulation, it is not enough to satisfy the above requirements. Through analysing the feedback current and voltage of the drive circuit under faulty and no-fault conditions and abstracting fault symptoms, this paper extends further the range of on-board diagnosis strategies, including an open circuit, a high-side drive short circuit to the low-side drive, a high- (or low-)side drive short circuit to the power supply, and a high- (or low-) side drive short circuit to the ground. After the circuit fault is confirmed, the diagnosis strategy can trigger an appropriate failure strategy to guarantee safety and to avoid emissions deterioration. In order to enhance the diagnosis reliability, the key constants of the diagnosis strategies are calibrated using a statistical method.

Robustness assessment and adaptive FDI for car engine

A new on-line fault detection and isolation (FDI) scheme proposed for engines using an adaptive neural network classifier is evaluated for a wide range of operational modes to check the robustness of the scheme in this paper. The neural classifier is adaptive to cope with the significant parameter uncertainty, disturbances, and environment changes. The developed scheme is capable of diagnosing faults in on-line mode and can be directly implemented in an on-board diagnosis system (hardware). The robustness of the FDI for the closed-loop system with crankshaft speed feedback is investigated by testing it for a wide range of operational modes including robustness against fixed and sinusoidal throttle angle inputs, change in load, change in an engine parameter, and all these changes occurring at the same time. The evaluations are performed using a mean value engine model (MVEM), which is a widely used benchmark model for engine control system and FDI system design. The simulation results confirm the robustness of the proposed method for various uncertainties and disturbances.

On-board monitoring and diagnosis for spark ignition engine air path via adaptive neural networks

This paper presents a new method for on-board fault diagnosis for the air path of spark ignition (SI) engines. The method uses a radial basis function (RBF) neural network to classify predefined possible faults from engine measurements, reporting fault occurrence as well as the type and size of a fault. After diagnosing faults in each sample interval, the weights and widths of the RBF fault classifier are updated with the measurements and appropriately selected target outputs. Consequently, the network can adapt to the time-varying dynamics of the engine and environment change so that the false alarm rate is greatly reduced and the required network size is also reduced. The developed scheme is assessed with various faults simulated on a mean value engine benchmark model and compared with a fixed-parameter RBF classifier. Simulation results demonstrate the effectiveness of the proposed method.

Development strategies for heavy-duty on-board diagnosis

When stage 2 of the “Heavy-Duty On-Board Diagnosis” (HD OBD) legislation comes into effect on October 1, 2008, the requirements on monitoring strategies will be much stricter. For the manufacturers of commercial vehicles, this will produce a further development area that is demanded by the legislator. This article by IAV GmbH provides an overview of the main legislative requirements and describes the technical measures that can be implemented to meet these demands in developing drive electronics and in vehicle calibration.

Emission control options for power two wheelers in Europe

This paper quantifies the emission contribution of motorcycles and mopeds in Europe, in the period 1999–2012. Projections show that these vehicles will emit more than 7% and 20% of total road transport CO and HC, respectively, by the year 2012, if no additional regulatory measures are taken. In contrast, they will continue to be negligible NO x (0.7%) and CO 2 (<1%) emitters, while their particulate matter (PM) emission contribution is expected to decline to below 1% in the future. The relative importance of their emissions, however, increases in urban environments, especially in southern European countries, which host large fleets of small two wheelers. Hence, further regulatory measures are being considered which include durability requirements for the emission controls, in-use compliance and roadworthiness procedures, on-board diagnostics, control of evaporation emissions, PM specific measures and new steps for emission standards. The study quantifies the environmental benefits and the costs associated with each measure, and calculates cost-effectiveness figures which may be used to evaluate each policy option. Results show that for the reduction of HC emissions, both evaporation control and roadworthiness tests are cost-effective while a further tightening of the emission standards for mopeds will bring the largest benefit. Additionally, on-board diagnosis for motorcycles is found to be an expensive measure with questionable effectiveness, while the replacement of mineral with synthetic lubricants would bring clear benefits with respect to PM of 2-stroke engines.

Research of Diagnosis Technique on PEFC Running Condition (Over Voltage Analysis and Diagnosis of PEFC by FFT)

Real time analysis on impedance spectroscopy in PEFC (Polymer Electrolyte Fuel Cell) was tried using FFT (Fast Fourier Transform) method to diagnose its running conditions. PEFC is simulated to equivalent circuit model with four resistances and three capacitances, and effects of running conditions on those were analyzed by the experiments. Results show that the voltage drops at each resistance correspond to over voltage calculated by conventional method and indicate distinctive characteristics according to deterioration of running condition. The logic is established to real time diagnosis of PEFC running conditions by classifying these voltage drops and to trace the flow chart. This method has capability of on-board diagnosis and control of fuel cell system vehicle.

HC-sensor for exhaust gases based on semiconducting doped SrTiO 3 for On-Board Diagnosis

In this contribution, a multilayer resistive sensor based on catalytically activated and non-activated SrTiO 3 is presented as a device for lean hydrocarbon sensing. This set-up should enable a compensation of oxygen cross interference. Whereas the catalytically activated part merely detects a variation in the oxygen equilibrium concentration in presence of hydrocarbons, the non-activated part strongly interacts with the reducing gases. Promising results with respect to stable sensor signals covering a wide hydrocarbon concentration range have been obtained using ethane and propane as hydrocarbon species. The sensor response is found to depend on the chain length of the used hydrocarbons. Using both sensor signals, an evaluation method for oxygen compensation has been studied. In addition, the cross interference of other common exhaust components has been investigated.

Research on Diagnosis Technique on PEFC Running Condition (High Speed Analysis by FFT and Feasibility Study of Diagnosis)

Real time analysis on impedance spectroscopy in PEFC (Polymer Electrolyte Fuel Cell) is tried using FFT (Fast Fourier Transform) method. It is proved this method can analyze the Cole·Cole plots of PEFC with high speed and high accuracy compared to conventional FRA (Frequency Response Analyzer). PEFC is simulated to equivalent circuit model with four resistances and three capacitances, and effects of running condition on those are analyzed by experiment. Results show this method has capability of on-board diagnosis and fuel cell system control.

On-board-diagnosis on diesel engines

Both the new European legislation for on-board-diagnosis (OBD) and the updated legislation in the United States let the diesel engine become more focussed by the diagnosis in general. The following article summarises the main requirements and describes some of the accompanying calibration tasks. These tasks are part of an OBD calibration that Bosch Engineering, a subsidiary of Robert Bosch GmbH, performs in an diesel engine calibration project.

On-Board Fault Diagnosis of Automated Manual Transmission Control System

The aim of this brief is to present an on-board fault-diagnosis strategy of automated-manual transmission (AMT) control system. In the strategy, a group of small local models of power train is employed to produce redundant information. The information redundancy in the local models of power train and the logic relations among different constitutions are used to diagnose the faults in sensors, actuators, and unit assemblages. Using small local models can avoid complex computation to satisfy the needs of on-board application and to enhance robustness as taking advantages of the analytical-redundancy diagnosis methods. In this brief, depiction is focused on the local models of power train, relations among the parameters of different assemblages as well as diagnostic logic. AMT and the advantages to use the analytical-redundancy diagnosis method in vehicle control systems are also concisely expounded. The test results show the efficaciousness of the methodology.

Aspects of Dynamic Three-Way Catalyst Behaviour Including Oxygen Storage

Current and future regulations regarding the exhaust gas system of automotive applications make the maximum exploitation of the Three-way catalytic converter's (TWC) performance mandatory. Furthermore, the on-board diagnosis (OBD) has to be able to monitor the performance of the TWC accurately. In order to gain deeper insight into the transient behaviour of a TWC, fast gas measurements of NO, HC, CO, CO2, O2 and H2 have been conducted and related to the response of different types of lambda sensors downstream of the TWC. Commercial type TWC's with three different levels of ageing have been used. Storage effects regarding oxygen and carbon monoxide, and the water-gas shift reaction can be interpreted from the measurements. Additionally, a method for the measurement of the oxygen storage capacity (OSC) is presented.

Model-based systems in the automotive industry

The automotive industry was the first to promote the development of applications of model-based systems technology on a broad scale and, as a result, has produced some of the most advanced prototypes and products. In this article, we illustrate the features and benefits of model-based systems and qualitative modeling by prototypes and application systems that were developed in the automotive industry to support on-board diagnosis, design for diagnosability, and failure modes and effects analysis.

Evaluation of on-board diagnosis methods for three-way catalytic converters.

On-board diagnosis (OBD) aims at detecting malfunctions of emission-related components of road vehicles. It is required by legislation in United States and the European Union, as it is considered to be beneficial for the reduction of vehicle-related air pollution. On-board diagnosis of the catalytic converter is a challenging task, as it relies on indirect assessments of catalyst activity. Several methods have been proposed for catalyst diagnosis, presenting a varying degree of correlation between the quantities used as OBD indexes and the actual tailpipe emissions. This paper evaluates two methods, with the support of mathematical modeling; in the first one, which is commonly used by vehicle manufacturers, malfunction detection relies on the oxygen storage properties of the catalyst, while in the second, detection relies on the heat released by the chemical reactions in the catalyst. Both are found to be sufficient for the diagnosis of catalytic converters for current legislation requirements. However, the thermal method presents higher sensitivity to low levels of catalyst deactivation and could therefore be more suitable for diagnosis of future, ultra-low-emitting vehicles.