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A prototype CO sensor based on anatase TiO2 was fabricated and tested in a Ford V6 engine. Fuel combustion was programmed to be near stoichiometric conditions, and emissions were monitored with an FT-IR analytical instrument. The sensor, positioned near the oxygen sensor in the exhaust manifold, was successfully tested for 50 cycles of revving and idling, and was observed to respond quickly and reproducibly. The sensor response was correlated to the CO concentration at specific engine temperatures and was found to vary systematically with increasing concentrations. This sensor has promising potentials to monitor the efficiency of the catalytic converter.

Legislation pertaining to automobile emissions has caused an increased focus on the cold-start performance of internal combustion engines. Of particular concern is the period of time before all available sensors become active. Present engine control strategies must rely on methods other than feedback control while these sensors are not active. Without feedback control during this critical period, engine emissions performance is not optimized. These conditions cause difficulty in performing comprehensive cold-start experiments. For these reasons, we have developed several methods for feedback control during cold-start to aid in laboratory investigations of engine emissions phenomena.

Engine knock has been recognized as a major problem limiting the development of fuel efficient spark-ignition engines. Detection methods employed in current knock control systems for spark ignition engines use a measurement of engine block vibration tuned to one or more resonance frequencies to extract knock-related information from the engine structural vibration. A major problem in the detection of knock (especially at higher engine speed) in commercial engines is the isolation of the desired signal from the contributions of the components other than those associated with the phenomenon under investigation. This is generally referred to as background noise. It is known that the engine knock resonance frequencies vary due to changes in combustion chamber volume and temperature during the expansion phase. Therefore, we propose an improved knock detection method using joint time-frequency analysis of engine block vibration and pressure signals.

An approach to fault diagnosis for internal combustion engines is considered. It is based on the estimation of cylinder indicated torque by means of sliding mode observers. Instead of measuring indicated pressure in cylinders directly, crankshaft speed is measured as the input of observers, which estimate the indicated torque. Several engine models are considered with different levels of complexity. The indicated torque estimation using sliding mode observers is based on the equivalent control method. The estimation technique is validated experimently on a research engine.

In recent years considerable interest has been placed on the detection of engine misfire. As part of the California Air Resources Board on-board diagnostics regulations for 1994 model year vehicles, misfire should be monitored continuously by the engine diagnostic system. It is expected that the next generation of on-board diagnostics regulations will demand monitoring of partial misfire as well. Several solutions to the misfire detection problem have been proposed and demonstrated for the detection of complete misfires. However, the performance of these methods in the presence of partial misfire is not altogether clear. The aim of this paper is to evaluate the performance of various misfire detection indices, all based on a measurement of crankshaft angular velocity, in the presence of partial misfire. The proposed algorithms are compared to a standard based on a measurement of indicated pressure.

This paper presents the real time implementation of detection filters for the diagnosis of incipient failures in electronically controlled internal combustion (IC) engines. The detection filters are implemented in a production vehicle. Recent results [1] have demonstrated the feasibility of a model-based failure detection and isolation (FDI) methodology for detecting partially failed components in electronically controlled vehicle subsystems. The present paper describes the real time application of the FDI concept to the detection of faults in sensors associated with the engine/controller In a detection filter, the performance of the engine/controller system is continuously compared to a prediction based on sensor measurements and an analytical model (typically a control model) of the system. Any discrepancy between actual and predicted performance is analyzed to identify the unique failure signatures related to specific system components.

This paper presents several applications of a precise, moderate sampling rate measurement of the crankshaft angular position of a reciprocating IC engine. It is shown that the measurement can be made with a relatively inexpensive noncontacting sensor. Given sufficient precision and sampling rate, the various applications include: crankshaft reference position measurements for ignition timing (gasoline fueled engines), or injector timing (for electronically controlled diesel engines); crankshaft angular speed and acceleration measurements for estimating instantaneous indicated torque, and for diagnosing engine malfunctions. The torque estimate is potentially useful for engine control, to improve engine performance with respect to reducing cycle to cycle and cylinder to cylinder nonuniformity, and with respect to fuel economy.

This paper presents the application of detection filters to the diagnosis of sensor and actuator failures in automotive control systems. The detection filter is the embodiment of a model-based failure detection and isolation (FDI) methodology, which utilizes analytical redundancy within a dynamical system (e.g., engine/controller) to isolate the cause and location of abnormal behavior (i.e., failures). The FDI methodology has been used, among other applications, in the aerospace industry for fault diagnosis of inertial navigation systems and flight controllers. This paper presents the philosophy and essential features of FDI theory, and describes the practical application of the method to the diagnosis of faults in the throttle position sensor in an electronically controlled IC engine. The paper also discusses the incorporation of FDI systems in the design process of a control strategy, with the aim of increasing reliability by embedding diagnostic features within the control strategy.

This paper presents a method for the isolation of misfiring cylinders in an internal combustion engine. The method is based on the measurement of the extrema of engine angular velocity. It has been shown that a number of indices can be derived from such a measurement, to provide an indication of engine performance degradation. In this study, an onboard microprocessor-based instrument samples the extrema of the engine velocity waveform in real time, generating an N or 2N vector representing each engine cycle, where N is the number of cylinders. The data is processed by matrix transformations which are designed to isolate specific faults and their intensity. The transforms are constructed in such a way as to yield a nonzero output only when a certain fault is encountered. The system is capable of detecting individual or multiple cylinder misfires, both complete and partial. Experimental verification has been carried out in a passenger vehicle.