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Coordinate measurement gages dominate in the area of dimensional control and variation reduction of automotive body assembly processes. However, coordinate measurement gages do not have the capability to track certain measured features. This incapability introduces inherent measurement error created by part (feature) mislocation in constrained non-measured directions. This inherent measurement error weakens the methods used for process control and variation reduction. In this paper, a principle of measurement uncertainty is developed in order to estimate the measurement error caused by this deficiency. The developed principle describes measurement error, which is independent of any other error related to the mechanical or optical coordinate measurement machines (CMMs, OCMMs). Additionally, an error map determined by the measurement uncertainty principle is created for error compensation.

Sound attenuation and flow loss reduction are often two competing demands in vehicle breathing systems. The present study considers a full vehicle exhaust system and investigates both the sound attenuation and the flow performance of production configurations including the catalyst, the resonator, and the muffler. Dynamometer experiments have been conducted with a firing Ford 3.0L, V-6 engine at wide-open throttle with speeds ranging from 1000 to 5000 rpm. Measurements including the flow rates, the temperatures and the absolute dynamic pressures of the hot exhaust gases at key locations (upstream and downstream of every component) with fast-response, water-cooled piezo-resistive pressure transducers facilitate the calculation of acoustic performance of each component, as well as the determination of flow losses caused by these elements and their influence on the engine performance.

An automotive absorption air conditioning system would use engine-rejected heat as its energy source. Three possible cycles were studied, based on using water-lithium bromide, ammonia-water, and refrigerant 22-dimethyl ether of tetraethylene glycol as the refrigerant-absorbent pairs. Heat balances were calculated for the cycles and for a comparable vapor compression cycle. Energy input requirements, cooling capacities, coefficients of performance, and pressures and temperatures at various points in the cycle are given. Energy input requirements are compared with test data on the heat rejection from a 390 cu in. displacement production engine.

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.

Adhesive joining is a common autobody subassembly technique especially for outer panels, where visible spot welding is objectionable. To accommodate mass production with the use of certain adhesives very high thermal gradient usually exists, which may result in panel dimensional distortion and variation. The temperature distribution over location and over time are monitored, and its impact to panel dimension is investigated. Experimental results on the effect of the distance between panel and induction coil on the panel temperature is obtained. The thermal induced shape distortion is simulated with a simplified FEA model. The approach to improvement of the induction curing process is discussed.