Olaf Magnor

State observer based analysis of crankshaft speed measurements with application to misfire detection

In this paper, a state observer based approach for monitoring fluctuations of the crankshaft angular speed and acceleration of an internal combustion engine is discussed. With this approach, irregularities in the speed or acceleration signal can be detected, which has application potential for misfire detection. The state observer used in this approach is a stationary Kalman filter that reconstructs the crankshaft speed from noise-corrupted measurements and generates estimates of the crankshaft angular acceleration. This is superior to generating acceleration from a coarse numerical differentiation of the speed signal, which would be more sensitive to high-frequency noise. Whereas in earlier Kalman-filtering approaches the underlying accelerating engine torque has been modeled as low-pass filtered white noise, a model that accounts for the periodic character of the torque is used here. Irregularities in the engine speed or acceleration signal can then be detected in the acceleration correction term of the state observer. This approach can elegantly handle missing measurements, which occur due to the instrumentation used to measure the engine speed in the car (tooth wheel with a gap). Experimental results show that even in a difficult case (large number of cylinders, high engine speed, low load) large peaks in the signal result when cylinders misfire or when cylinders resume firing.

An optimization-based approach for the calibration of lookup tables in electronic engine control

This paper discusses the use of a parameter estimation approach for the calibration of electronic engine control software from an industrial perspective. Many functions in the software of automotive electronic engine control units are based on lookup tables. Calibrating, that is, tuning the entries of these lookup tables, is a crucial step in the process of automotive software engineering. At first sight, this corresponds to a standard parameter estimation problem. In the practical application, however, the calibrated parameters have to fulfil additional requirements. These additional requirements are discussed in this paper and it is illustrated how they can be included in an optimization-based calibration process. A software tool is described that has been developed to allow the calibration engineer, without having to be familiar with the mathematical background, to easily formulate these requirements, carry out the optimization, and analyze the results. The steps that are carried out in the optimization-based calibration process are outlined, and the advantages of this approach are discussed

Misfire Detection Using a Neural Network Based Pattern Recognition Technique

This contribution investigates the practical application of artificial neural networks to misfire detection in gasoline engines.The problem of misfire detection is formulated as a pattern recognition problem. A feed-forward multiple-layer neural network is used for the classification of firing and misfiring events. Emphasis is given on the trade-off between performance, computational cost and implementabilitv of the technique on a production electronic control unit (ECL). The developed technique is applied to a six cylinder gasoline engine to detect misfire events over the whole range of operation defined by official on board diagnosis (OBD) regulations. Experimental results on a passenger car are presented.

Improved reference system for high precision blade tip timing on axial compressors

Blade tip timing is an upcoming technology to research possibilities of working point identification and phenomena like stall and blade vibrations for axial compressors. This method determines blade bendings for each individual compressor blade. Due to their high timing resolution optical sensors are often used in this field. Real blade bendings are often of very small amplitudes in the range of micrometers. So its important to have a reference system that is as accurate as possible. This paper describes a method which guarantees a high resolution and high precision reference system to improve the results of blade tip timing.

A Rapid Calibration® tool for engine control software and its application to misfire diagnosis functions

Rigid legislation requirements on vehicle emissions and customer demands on comfort and efficiency have lead to a continuously increasing complexity of modern engine management systems, accompanied by a growing number of functions for engine control and component diagnosis, which all have to be calibrated. Nevertheless, for competitive reasons, time efficient methods for calibration are needed, where the accuracy of calibration is verified and well documented. For this purpose, the division of Powertrain Mechatronics Development Gasoline Engines (MD-G) of the IAV GmbH developed the idea of Rapid Calibrationreg (RC). In the RC tool environment in-vehicle measurements are automatically configured and executed, whereas the evaluation of the measurements, i.e. the calibration process, is mostly done on the basis of off-line optimization algorithms and simulation tools. Finally, documentation files, like for example slide presentation files, are automatically generated and statistical analyzing methods, which prove the quality of the calibration, are applied. This contribution describes, from an engineers point of view, the use of the Rapid Calibrationreg tool environment for calibrating the misfire diagnosis function

Zustandsbeobachter für periodische Signale: Anwendung zur Erkennung von Verbrennungsaussetzern (State Observers for Periodic Signals: A Case Study in Misfire Detection)

Abstract Viele der im Automobil auftretenden Signale weisen aufgrund der periodischen Energieumsetzung des Verbrennungsmotors ebenfalls periodischen Charakter auf. Zur Analyse dieser Signale sind Zustandsbeobachter auf Basis eines Signalmodells, welches diese Periodizität nachbildet, sehr gut geeignet. Der vorliegende Beitrag zeigt dies am Beispiel der Analyse des Kurbelwellengeschwindigkeitssignals zur Erkennung von Verbrennungsaussetzern.