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This paper describes the technique of in-cylinder ionization sensing in a common rail diesel engine. The technology detects in real time, the start of combustion for both pilot and main combustion enabling the fuel control strategy to change from open to closed loop, thus, maintaining the desired start of combustion for all speeds and loads. Additionally, the ionization sensing enables the ECM to truly correct for changes in ignition delays caused by as an example a change in fuel cetane number or in air, fuel and engine temperature. The conclusions are that ionization sensing improves the ability to control a diesel engine and is a feasible technology for production vehicles.

Engine tests were conducted to study the effect of fuel-air mixture preparation on the combustion and emission performance of a two-stroke direct-injection engine. The in-cylinder mixture distribution was altered by changing the injection system, injection timing, and by substituting the air in an air-assisted injector with nitrogen. Two injection systems which produce significantly different mixtures were investigated; an air-assisted injector with a highly atomized spray, and a single-fluid high pressure-swirl injector with a dense penetrating spray. The engine was operated at overall A/F ratios of 30:1, where stratification was necessary to ensure stable combustion; and at 20:1 and 15:1 where it was possible to operate in a nearly homogeneous mode. Moderate engine speeds and loads were investigated. The effects of the burning-zone A/F ratio were isolated by using nitrogen as the working fluid in the air-assist injector.

A high pressure outwardly opening fuel injector has been developed to produce sprays that meet the stringent requirements of gasoline direct injection (DI) combustion systems. Predictions of spray characteristics have been made using KIVA-3 in conjunction with Star-CD injector flow modeling. After some modeling iterations, the nozzle design has been optimized for the required flow, injector performance, and spray characteristics. The hardware test results of flow and spray have confirmed the numerical modeling accuracy and the spray quality. The spray's average Sauter mean diameter (SMD) is less than 15 microns at 30 mm distance from the nozzle. The DV90, defined as the drop diameter such that 90% of the total liquid volume is in drops of smaller diameter, is less than 40 microns. The maximum penetration is about 70 mm into air at atmospheric pressure. An initial spray slug is not created due to the absence of a sac volume.

The use of advanced electron microscopy techniques to characterize both the bulk and near-atomic level microstructural evolution of catalyst materials during different dynamometer/vehicle aging cycles is an integral part of understanding catalyst deactivation. The study described here was undertaken to evaluate thermally-induced microstructural changes which caused the progressive loss of catalyst performance in a three-way automotive catalyst. Several different catalyst processing variables, for example changing the washcoat ceria content, were also evaluated as a function of aging cycle and thermal history. A number of thermally-induced microstructural changes were identified using high resolution electron microscopy techniques that contributed to the deactivation of the catalyst, including sintering of all washcoat constituents, γ-alumina transforming to α-, β-, and δ-alumina, precious metal redistribution, and constituent encapsulation.

In this paper, finite element shape optimization is used to determine the optimum air cleaner shape and rib design for low shell noise. Shape variables are used to vary the height and location of rib elements, as well as vary the shape of the air cleaner surfaces. The optimization code evaluates each design variation and selects a search direction that will reduce surface velocity. Sound power radiation is calculated for each optimized design using an acoustic code. Large reductions in shell noise were achieved by optimizing the shape of the air cleaner surface and rib design. Optimization of the rib pattern alone yielded a local optimization, as opposed to a global optimization that represented the best possible design.

The problem being investigated involves a noise-quality issue on a power steering application, when a sudden change of steering wheel angle generates an unwanted steering system noise or “Squawk.” This phenomenon is mostly observed during parking maneuvers, especially at lock positions and when the hydraulic fluid reaches a critical temperature on the specific application. The objective of the work to solve this noise-quality issue was to first identify the cause and then eliminate the Squawk noise. There were several constraints: No change could be made in the properties or type of hydraulic fluid used due to specification requirements; Steering wheel valve torsion bar characteristic (torque vs. angle) needed to be maintained within specification for ride and handling purposes; and, In addition to the mentioned constraints, a high capability of noise elimination generated by the production tolerances and dispersion has been considered.

California Ultra Low Emission Vehicle (ULEV) standards call for a significant reduction in the amount of harmful gases that enter the environment from vehicle exhaust. The Electrically Heated Catalyst (EHC) is a possible solution to reduce emissions. A competitive analysis benchmarking study was completed in order to find an optimum EHC design that will perform to ULEV standards. Four suppliers submitted samples and the EHC designs were rigorously tested for temperature, pressure drop, and emissions performance while being aged at different levels.