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A laboratory aging study was performed on samples of a lean NOx trap with platinum group metal (PGM) loadings of 0.53, 1.06, 2.12, and 3.18 g/liter. The LNT samples were aged at inlet temperatures of 650°C, 750°C, 800°C, and 850°C behind samples of a three-way catalyst that were aged on a pulse-flame combustion reactor with a Ford-proprietary durability schedule representing 80,000 km of customer use. For all aging temperatures, higher PGM loadings were beneficial for low temperature NOx performance, attributable to an increase in the oxidation of NO to NO2. Conversely, lower PGM loadings were beneficial for high temperature NOx performance after aging at 650°C and 750°C, as higher loadings promoted the decomposition of the nitrates during lean operation and thereby decreased the NOx storage capability at high temperatures. Also, higher PGM loadings increased the OSC of the trap and thereby increased the purge requirements.

A method for non-intrusive measurement of spark plug fouling, burn quality, pre-ignition and spark characteristics is described. The technique relies on a continuous monitoring of the leakage current to the spark plug centre electrode, via a high voltage diode stand off arrangement. By way of demonstration, the system operation is reported for investigations of cold start plug fouling.

An advanced high speed hydraulic system consisting of a special ram and hardware digital controller is described with which a hot wire anemometer has been flown across the bore of a motored spark ignition engine. The only access to the engine was a single 3mm diameter hole and thus the engine modifications required for this measurement technique ate minimised. The velocity imposed by the ram system enabled the spatial turbulent structure to be measured with the advantage of an imposed ‘mean flow’, which makes confident analysis of the data possible. Using a novel learning procedure, the required hot wire trajectories can be followed with great accuracy and repeatability. Some results are presented from the engine as well as a simple method for reliable hot wire calibration.

This paper describes a system for knock detection in automobile engines using the spark plug. Operation is based on detection of the effect of the characteristic pressure fluctuations in the cylinder on the conductivity of the slightly ionized combustion gases in the vicinity of the plug gap. A signal processing method is described which gives adequate signal to noise ratio up to high engine speed.