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A sampling system was developed to measure the evolution of the speciated hydrocarbon emissions from a single-cylinder SI engine in a simulated starting and warm-up procedure. A sequence of exhaust samples was drawn and stored for gas chromatograph analysis. The individual sampling aperture was set at 0.13 s which corresponds to ∼ 1 cycle at 900 rpm. The positions of the apertures (in time) were controlled by a computer and were spaced appropriately to capture the warm-up process. The time resolution was of the order of 1 to 2 cycles (at 900 rpm). Results for four different fuels are reported: n-pentane/iso-octane mixture at volume ratio of 20/80 to study the effect of a light fuel component in the mixture; n-decane/iso-octane mixture at 10/90 to study the effect of a heavy fuel component in the mixture; m-xylene and iso-octane at 25/75 to study the effect of an aromatics in the mixture; and a calibration gasoline.

An engine-based test has been developed to measure the oxygen storage capacity of a catalyst. The test utilizes the difference in the engine-out and tailpipe A/F ratios following rich-to-lean and lean-to-rich A/F transitions in order to quantify the storage or release of oxygen. The technique also results in the determination of the water-gas shift constant for the tailpipe exhaust. The technique was used to measure the oxygen storage capacity of a fresh catalytic converter at inlet temperatures of 400, 500, and 600°C for catalyst volumes of 1.5L and 2.8L. The procedure was repeated after the converter had been aged at an inlet temperature of 800°C for 20, 40, and 60 hours. The oxygen storage capacities are related to the emissions performance of the converter on A/F ratio sweep tests. For the fresh converter, the calculated oxygen storage capacity increased with temperature.

The effects of catalyst and fuel formulation changes were investigated on vehicles meeting European Stage II (94/12/EC) emission limits when tested over the modified European test cycle. The OEM standard Pt/Rh catalyst formulation was compared with advanced Pd/Rh catalysts, at nominally the same PGM cost, and with Pd/Rh catalysts at increased PGM loadings. No other changes were made to the vehicles. The largest relative emissions benefits for the advanced Pd/Rh catalysts at equivalent PGM cost were 28% for THC, 30% for CO and 22% for NOx. Pd/Rh catalysts with higher PGM loadings gave further improvements in emissions, with total reductions of 38% for THC, 40% for CO and 31% for NOx compared to the standard OEM catalyst. In addition, one of the vehicles was tested with a Pt/Pd/Rh catalyst formulation. The performance of this catalyst was comparable with the Pd/Rh catalyst at similar PGM loading.

The effects of fuel formulation changes on vehicles meeting European Stage 1 (91/441/EEC) and Stage II (94/12/EC) emission limits have been investigated. Vehicles in the Euro Stage II fleet were advanced specification versions of the vehicle models in the Euro Stage I fleet. However, the basic engine blocks and capacity were the same. The observed improvements in emissions were attributed to changes, such as position of the catalyst and lambda sensor, improved fuel delivery systems, and to improvements in engine control strategy. These engine modifications resulted in reduced catalyst light-off times and improved AFR control. Emissions improvements, over the modified European test cycle, as a result of these changes were approximately 50% for CO and NOx and 30% for THC. A fuel matrix was designed in order to study the effect of six fuel parameters on exhaust emissions from the two levels of vehicle technology.

The aerospace industry has entered a new level of World Class Manufacturing, in which manufacturing functions require fixturing to be just as flexible as the machine tool doing the operation. Flexible tooling has opened new doors for the aerospace industry by creating new tools which are automatically reconfigurable and totally reusable on future programs. Benefits include decreases in non-recurring costs, (such as in the area of tool design and fabrication) and recurring costs, (such as in the area of tool setup / removal and storage).

Coldworking holes is an established manufacturing procedure in the aerospace industry. There are two coldworking methods used today: split-sleeve and split-mandrel. The intricate steps of these processes are not completely understood. There has been no investigation into the differences in the mechanisms of the two processes. Initial results from an ongoing program reveal that the differences in the mechanisms impart the split-mandrel process with advantages over the split-sleeve process, including the ability to coldwork 7000 series aluminum without shear cracking at the axial ridge, and the ability to effectively automate the process.

Three European gasoline vehicles, homologated to European Stage II limits, and two US gasoline vehicles, certified to Californian TLEV limits, were evaluated over the new European test cycle for year 2000 standards and the US Federal Test Procedure. Three advanced catalyst technologies were tested on these vehicles, in the original equipment converter position in all but one case, without any additions or changes to the existing emission control system. Prior to testing they were aged on a cycle representing 80,000 km road durability. Up to 30% reductions in emissions were achieved from those for which the vehicles were homologated, at an incremental cost in precious metal of 12 - 23 US$ per liter of catalyst compared to the original converter precious metal value (precious metal prices of 16 July 1996).

A 100,000-mile fleet test in nine gasoline-powered passenger cars was carried out. The impact of motor oil phosphorus levels on engine durability, oil degradation, and exhaust emissions has been previously described. The results of additional emissions control systems studies, and measurements of the engine oil additive elements which are present on the catalysts, are now presented. These studies include conversion efficiencies for the aged catalyst at the end of the test by a combination of light-off experiments, air/fuel sweep tests, and an auto-driver FTP. The performance of the lambda sensors is also presented. The relationships between engine oil additive levels and composition and emissions systems durability is presented.

The effect of changing catalyst precious metal ratios and loadings on close coupled catalytic converter efficiencies has been studied. The three precious metals were platinum, palladium and rhodium. The specific matrix used for the development of response surface models is a central composite design and provides the capability of visually optimising the precious metal loadings. Catalysts were evaluated using perturbed scans. lightoff curves from the dynamometer aged, and vehicle emission tests. These scans show percent conversion efficiencies of the three legislated gases; HC, CO and NOx, over a range of Air Fuel Ratios (λ). Whilst lean and rich lightoff curves provide indications of conversion efficiencies at varying temperatures. Prior to testing the catalysts were aged, using an accelerated dynamometer ageing process, to 80K simulated kilometres. The catalysts were then fitted to a vehicle and chassis roll emission tests conducted.

Inter-ring gas pressure and piston ring motion are considered important for the control of oil consumption, particulate emissions, and reduced friction. For this reason, inter-ring gas pressure was measured on a diesel engine. Two different ring pack configurations were tested (positive and negative twist second rings). A significant difference in measured inter-ring pressure was observed. The measurements were compared to the predictions of a cylinder kit model with favorable results. Predictions showed that the observed difference between measured inter-ring pressures is caused by a significant difference in ring motion. The reasons for these differences are explained in this paper.

Only a limited understanding of the oil consumption mechanism appears to exist, especially oil consumption under transient engine operating conditions. This is probably due to the difficulty in engine instrumentation for measuring not only oil consumption, but also for measuring the associated in-cylinder variables. Because of this difficulty, a relatively large number of experiments and tests are often necessary for the development of each engine design in order to achieve the target oil consumption that meets the requirements for particulate emissions standards, oil economy, and engine reliability and durability. Increased understanding and logical approaches are believed to be necessary in developing the oil-consumption reduction technology that effectively and efficiently accomplishes the tasks of low oil-consumption engine development.

A 1990 Ford Taurus operated on reformulated gasoline was tested under three modes of malfunction: disabled heated exhaust gas oxygen (HEGO) sensor, inactive catalytic converter, and controlled misfire. The vehicle was run for four U.S. EPA UDDS driving schedule (FTP-75) tests at each of the malfunction conditions, as well as under normal operating conditions. An extensive set of emissions data were collected. In addition to the regulated emissions (HC, CO, and NOx), a detailed chemical analysis was carried out to determine the gas- and particle-phase non-regulated emissions. The effect of vehicle malfunction on gas phase emissions was significantly greater than it was on particle phase emissions. For example, CO emissions ranged from 2.57 g/mi (normal operation) to 34.77 g/mi (disable HEGO). Total HCs varied from 0.22 g/mi (normal operation) to 2.21 g/mi (blank catalyst). Emissions of air toxics (1,3-butadiene, benzene, acetaldehyde, and formaldehyde) were also significantly effected.

Meeting the California Medium-Duty truck emissions standards presents a significant challenge to automotive engineers due to the combination of sustained high temperature exhaust conditions, high flow rates and relatively high engine out emissions. A successful catalyst for an exhaust treatment system must be resistant to high temperature deactivation, maintain cold start performance and display high three-way conversion efficiencies under most operating conditions. This paper describes a catalyst technology and precious metal loading study targeting a California Medium-Duty truck LEV (MDV2) application. At the same time a direction is presented for optimizing toward the Federal Tier 1 standard through reduction of precious metal use. The paper identifies catalytic formulations for a twin substrate, 1.23 L medium-coupled converter. Two are used per vehicle, mounted 45 cm downstream of each manifold on a 5.7 L V8 engine.

A parametric study was performed to investigate the interactions between Pd warm-up and underfloor converters on FTP emissions. Three different Pd warm-up converters were evaluated with six different underfloor converters on two different engines. The Pd warm-up converters primarily differed in the amount of ceria in the catalyst washcoat. These warm-up converters had a catalyst of 0.52 liters and a Pd loading of 100 g/ft3. The underfloor converters had a catalyst volume of 2.67 liters. Two Pt/Rh and one Pd catalyst technology were used in the underfloor converters. Each underfloor catalyst technology was investigated at two different loadings. The Pt/Rh underfloor converters were evaluated at 25 and 50 g/ft3 at a Pt/Rh ratio of 14/1. The Pd containing underfloor converters were evaluated at 50 and 100 g/ft3. All of the converters used in this study were dynamometer aged appropriately with respect to their intended position in the exhaust system.

Rare earths compounds, especially CeO2, are widely used in automotive catalysis. Cerium dioxide contributes to the stabilization of precious metals but is particularly well known to be the active component for oxygen storage capacity (OSC). Standard cerium dioxide has poor thermal stability at temperatures higher than 800°C. A new generation of metal based oxides has been studied possessing high thermal and OSC stability. We have demonstrated that commercially available Ce rich solid solutions of (Ce, Zr)O2 showed the highest surface areas with remarkably improved OSC and phase stability versus temperature.

This study reports on an investigation to determine the root cause of engine failures that occurred when engines were run on low sulfur diesel fuel and a high ash SAE 40 API CD quality synthetic oil. Four WARTSILA SACM DIESEL 4-stoke UD45 V16 engines being used in a power generation application experienced high blowby at relatively low engine hours. In addition filters were plugging in less than 30 hours of operation. Borescope inspection of the engines revealed heavy deposits on the top of the pistons and scuffed cylinder liners. Upon disassembly stuck rings were found with heavy deposits also present on the ring lands and inside the top and second ring grooves. A thorough analysis of the engine operating conditions and engine design revealed nothing that would have contributed to the engine failures. Oil analysis showed no unusual trends other than a slight but consistent increase in calcium content.

In our earlier work [1], an investigation was conducted to study lubricant formulation effects, engine type and mode of engine operation on the composition and nature of diesel soot and its interactions with the crankcase lubricant. Tests were run in two types of heavy duty diesel engines the Mack EM6-285 and the GM 6.2L. Part 2 studies the impact of oil composition on the surface and bulk chemistry of soot and on the ability of the fluid to handle soot produced in the GM 6.5L engine. The study also determined what portion of lubricant viscosity growth is related to bulk oil oxidation versus soot contamination. A statistically designed experiment was developed to examine the effects of dispersant level dispersant type, antioxidant level, and detergent metal type on average roller follower shaft wear, viscosity growth and other measured responses. The effect of run order on these measurements is also studied. Key results of this study are as follows.

Using the most ideal packages of additives in engine oils does not enable one to avoid the development of mechanical admixtures of particulate contaminants from fuel combustion byproducts and airborne contaminants. In this connection, one must modernize the engine design to accommodate the removal of harmful particulate contaminants, which exist in particle sizes of 3-5 micrometers or greater [1].* It should be noted that even the most active ashless dispersants cannot accommodate higher and higher concentrations of sludge, soot, and airborne contaminants without eventually losing their ability to suspend these contaminants [2, 3]. As more and more contaminants continue to concentrate in the crankcase, it becomes necessary to change the engine oil. It is known that polar-active species (asphalt-resins) can be absorbed on non-organic particulates [4]. These agglomerates may then be physically separated from the oil with the use of a centrifugal cleaner.

A bench scale apparatus and accelerated test protocol were developed to evaluate the effect of contamination of automatic transmsission fluid by mg/kg levels of water on cellulose frictional clutch surfaces. The testing indicated that water added at levels as low as 600 mg/kg migrated to the surface of untreated paper frictionals and contributed to loss of the paper coating and erratic torque transfer properties. Treated, “high performance” paper frictional surfaces showed less physical damage but the same torque transfer effects from water contaminated ATF. A mechanism of the water coating, swelling and weakening the hydrophillic cellulose fibers, with subsequent destruction due to hydrodynamic shear was proposed.

The minimum thickness of the oil film lubricating piston rings was measured successfully under motoring conditions by means of Eddy Current Sensors which were mounted on the liner. The measurements show the influences of engine speed, the viscosity of the oils and the profile of rings on their lubrication. The results also show the effects of hydrodynamic lubrication and oil starvation at the inlet of the rings. Under motoring condition, the minimum oil film thickness has no significant difference for the four strokes and it reaches a minimum value even though the rings are fully lubricated(without oil ring).