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A new high-bandwidth transient test system is being developed that allows a single cylinder research engine to be tested under conditions nearly identical to those experienced by individual cylinders of a multi-cylinder engine. The system consists of two unique test components: a high bandwidth transient hydrostatic dynamometer capable of simulating the combustion and rotational dynamics of a multi-cylinder engine, and an air intake simulator that pulls air from the intake manifold plenum to simulate air induction characteristics of the multi-cylinder engine. The system makes it possible to evaluate preliminary engine control strategies and perform more detailed hardware development early in a development program when representative multi-cylinder engines may not be available. This reduces engine development time and allows the transition to multi-cylinder engine hardware to proceed with fewer design changes and less cost.

Nonlinear observer theories are applied to the engine estimation problem in order to reconstruct engine states based on the measured engine variables, and dynamic mean torque production and cylinder-by-cylinder engine models. Engine cylinder and intake manifold pressures are two important factors in engine control and diagnostics. This paper discusses how to design nonlinear engine cylinder pressure and intake manifold pressure observers that have good robustness and estimation accuracy. Sliding mode theory in Variable Structure Systems (VSS) have shown good performance and been successfully applied to many nonlinear systems. Accordingly, sliding observers are selected for this study.

Stoichiometric air-fuel ratio control during transient operation requires an accurate estimate or measurement of the instantaneous air flow rate in an engine. Two methods are commonly used for determining engine air flow rate: air-mass sensing and conventional “speed-density.” The lead air flow information provided by air-mass sensors helps compensate for manifold filling and other fuel system delays. However, the high cost (and sometimes lower reliability) of air-mass sensors has led many manufacturers to continue to use the less accurate speed-density method for determining air flow rate. This paper develops a model-based nonlinear manifold pressure observer that estimates the flow rates at the throttle and the intake ports of an engine using speed-density type sensors. The throttle flow rate estimate can be used instead of an air-mass sensor to provide the lead information necessary for accurate transient air-fuel control on TBI engines.

A nonlinear model-based method for engine misfire detection has been proposed in the earlier work [2]. Many possible reasons for persistent cylinder misfire (e.g., a burned inlet valve or other faults), however, still need to be identified. Identification of engine misfire enables engineers, vehicle operators or technicians to trace the cause of misfire and to identify the faulty components in the engine. Also, a cylinder-by-cylinder manifold model will provide a considerably more accurate estimate of individual cylinder air flows. This paper develops a model-based nonlinear intake manifold pressure observer and an algorithm to identify a burned inlet valve. The proposed manifold model is a runner-by-runner model. A nonlinear observer using this runner-by-runner model can estimate the plenum pressure and all individual runner pressures and their subsequent flows. The estimate is then used as an indication of a faulty inlet valve, one of the possible causes of engine misfire.