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There are benefits of using ultra thin wall (UTW) substrates (i.e., 900/2, 400/4, etc) in lowering cost and emission level. However, the more fragile mechanical characteristics of the UTW present a challenge to design and manufacture of robust catalytic converters. This paper describes a method of canning trial, where a combined Design of Experiment / Monte-Carlo analysis method was used, to develop and validate a canning method for ultra thin wall substrates. Canning trials were conducted in two stages-- Prototype Canning Trial and Production Canning Trial. In Prototype Canning Trial, the root cause of substrate failure was identified and a model for predicting substrate failure was established. Key factors affecting scrap rate and gap capability were identified and predictions were performed on scrap rate and gap capability with the allowed variations in the key factors. The results provided guidelines in designing production line and process control.

Application of Ultra Thin Wall (UTW) ceramic substrates in the catalytic converter system requires the canner and component manufacturers to better understand the root cause and physics behind substrate breakage during the canning process. For this purpose, a ceramic substrate strength study for shoebox design has been conducted within Visteon Corporation. Computer Numerical Control (CNC) machined top and bottom fixtures, with identical inner surfaces as shoebox converter upper and lower shells, were used to crush mat wrapped substrates. Thin film pressure sensor technology enables the recording of substrate surface pressure during the compression process. Shell rib, washcoat, canning speed and cell density effects on substrate failure have been experimentally investigated. The development of a mathematical model helps to identify a better indicator to evaluate the substrate strength in the canning process and establish the strength for uncoated & coated substrates.

A reduced chemical kinetic model has been developed for the prediction of major oxidation behavior of primary reference fuels (PRF's) in a motored engine, including ignition delay, preignition heat release, fuel consumption, CO formation and production of other species classes. This model consists of 29 reactions with 20 active species and was tuned to be applicable for the neat PRF's, 87 PRF and 63 PRF, and at various engine conditions. At the motored engine condition where detailed species data were generated, the model reproduces the ignition delay and the preignition heat release quite well (to within 15%). Fuel consumption and CO formation predictions differed from experiments by at most 25% for all of the four fuels. Predictions for other species classes generally agreed with experiments. As inlet temperature was varied, the experimentally observed negative temperature coefficient (NTC) behavior of iso-octane and 87 PRF was reproduced by the model.

This experimental study was conducted in a motored research engine to investigate the effect of blending methanol and ethanol on hydrocarbon oxidation and autoignition. An 87 octane mixture of primary reference fuels, 87 PRF, was blended with small percentages of the alcohols to yield a constant gravimetric oxygen percentage in the fuel. The stoichiometric fuel mixtures and neat methanol and ethanol were tested in a modified single-cylinder engine at a compression ratio of 8.2. Supercharging and heating of the intake charge were used to control reactivity. The inlet gas temperature was increased from 325 K to the point of autoignition or the maximum achievable temperature of 500 K. Exhaust carbon monoxide levels and in-cylinder pressure histories were monitored in order to determine and quantify reactivity.

Autoignition chemistry of n-heptane, iso-octane and an 87 octane blend, 87 PRF, was studied in a single-cylinder modified Wisconsin model AENL engine under motored conditions. Use of a fast-acting sampling valve and gas chromatographic analysis allowed measurement of in-cylinder gas composition during the ignition process. Crank angle resolved species evolution profiles were generated for all three fuels at a fixed inlet temperature of 376 K. For n-heptane, the measurements were made during a cyclically repeatable two stage ignition process up to the point of hot ignition (the second stage ignition). These n-heptane experiments were run at ø = 0.3 to avoid excessive pressure rise at hot ignition which might damage our engine. iso-Octane and 87 PRF were run at stoichiometric equivalence ratio which did not have a second stage ignition, and species were measured only during the first stage of ignition.

This paper presents results of studies investigating the effect of octane enhancing ethers on the reactivity of an 87 octane mixture of primary reference fuels, 87 PRF, in a motored engine. 87 PRF was blended with small percentages of MTBE, ETBE, TAME and DIPE based on a constant gravimetric oxygen percentage in the fuel. The experiments were conducted in a modified single-cylinder Wisconsin AENL engine at compression ratios of 5.2 and 8.2. Supercharging and heating of the intake charge were used to control reactivity. The inlet gas temperature was increased from 320 K, where no reactivity occurred, until either autoignition occurred or the maximum temperature of the facility was reached. Exhaust carbon monoxide levels and in-cylinder pressure histories were monitored in order to determine and quantify reactivity.

We investigated the ability of a reduced chemical kinetic model of 18 reactions and 13 active species to predict the heat release for a blend of primary reference fuels with octane rating 63 in a motored research engine. Given the initial fuel-air mixture concentration and temperature, the chemical kinetic model is used to predict temperature, heat release and species concentrations as a function of time or crank angle by integrating the coupled rate and energy equations. For comparison, we independently calculated heat release from measured pressure data using a standard thermodynamic model.