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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).

Over the years a wide variety of lubricant types have been used for manual transmissions. Within the last decade, changes in vehicle design, operation and loading factors have led to the development of dedicated fluids to ensure optimized transmission operation. This paper reviews these changes and outlines the market forces that have necessitated the current commercial vehicle heavy-duty manual transmission fluid specifications and categories.

The International Lubricant Standardization and Approval Committee (ILSAC) GF-2 specification requires Passenger Car Motor Oils to provide enhanced fuel economy in a modern low friction engine as measured by the ASTM Sequence VIA This paper details fundamental studies of the effect of zinc dithiophosphate, both type and level, on fuel economy as measured by this low friction engine The Sequence VIA was found to be very sensitive to both the level of zinc dithiophosphate and the type of alcohol functionality associated with it Increasing the level of zinc dithiophosphate was found to enhance fuel economy as measured by this test particularly in the SAE 10W-30 viscosity grade Secondary zinc dithiophosphates outperformed both primary and aryl types This paper will discuss these findings, as well as report on some fundamental studies using 31P-NMR and surface film analysis to determine the fate of zinc dithiophosphate during the course of this test

The processes of hydrocarbons diffusing into and out of the oil film are studied. The theoretical simulations show that the magnitude of desorbed hydrocarbons from the oil film increases with the increase of the oil film thickness until a critical one at which it reaches a maximum, and the maximum value changes little when the oil film is thicker than the critical one. Under normal operating conditions, the oil film thickness is approximately equal to or greater than the critical one, so that the oil film nearly has its definite and maximum contribution to the exhausted hydrocarbons. The same conclusion can also be drawn from the experimental data. The measured concentration of unburnt hydrocarbons almost has no difference as far as the different petroleum-based oils and the ring packs are concerned, which may cause the oil film thickness to change. The ‘oil-free’ engine test proves that the oil film may contribute about 28 percent to the total hydrocarbon emissions of SI engine.

Cycle resolved fuel droplet dynamics measurements in the inlet port of an S.I. engine were performed under firing conditions in order to study real dynamic effects in the fuel flow to the engine. A Phase Doppler Particle Analyzer (PDPA) was used to detect the droplet size and velocity. The optical access was through a glass window in the bottom of the intake channel. The PDPA was synchronised with the engine combustion cycle in order to study the results in the engine frequency domain. The measurements were performed over the cross section of the channel. Different injection timing and engine running conditions were investigated, using standard unleaded gasoline. The results show that, during the camshaft's overlap period, there exists a “push-back” droplets effect, due to the pressure difference between the inlet manifold and the cylinder, that transports droplets far back in the inlet manifold.

The droplet velocity, size and distributions of iso-octane fuel from single hole and twin jet air-assist injectors have been measured by phase Doppler velocimetry in the pent-roof for two cylinder head designs of firing four-valve engines running at 1500 rpm, together with the airflow during induction and compression. The use of the twin jet air-assist injector together with the introduction of a transfer-passage between the two intake ports of a Honda VTEC-E valve train arrangement resulted in reduction in ISNOx and COV-1mep of the order of half of those with the single hole injector design without a transfer passage. Droplets, for both heads and injectors, having passed the inlet valves, impinged directly onto the sleeve opposite to their entry without striking the exhaust valves and had velocities up to 30 m/s and Sauter mean diameters which varied from 20 to 50pm.

An experimental study was made to investigate the spray characteristics of high pressure fuel injectors for direct-injection gasoline engines. The global spray development process was visualized using two-dimensional laser Mie scattering technique. The spray atomization process was characterized by Phase Doppler particle analyzer. The transient spray development process was investigated under different fuel injection conditions as a function of the time after the fuel injection start. The effects of injector design, fuel injection pressure, injection duration, ambient pressure, and fuel property on the spray breakup and atomization characteristics were studied in details. Two clear counter-rotating recirculation zones are observed at the later stage or after the end of fuel injection inside the fuel sprays with a small momentum. The circumferential distribution of the spray from the large-angle injector is quite irregular and looks like a star with several wings projected out.

The conversion of spark ignited and compression ignited engines to run on natural gas is established technology Engines have also been designed and built specifically for natural gas These engines have been used primarily in stationary applications with relatively constant operating conditions More recently, environmental pressures and economic considerations have made the use of natural gas attractive for transportation applications The urban transit bus population is particularly well suited to compressed natural gas fueling The basic engine designs for stationary natural gas service and conventionally fueled (diesel and gasoline) transportation service are similar Differences in operating conditions and maintenance practices have resulted in two distinct lubricant product groups Stationary natural gas engine lubricants tend to be high viscosity monograde formulations with a low ash content Lubricants for conventionally-fueled transportation applications are frequently multigrades with considerably higher ash content The lubricant needs for natural gas in transportation applications may not be adequately met with the lubricant product groups widely usable for stationary natural gas or conventionally fueled transportation Lubricant products have been designed to combine features identified as desirable for natural gas fueling and the needs of transportation usage The performance of these products is supported by laboratory engine data

The concept of long drain super high performance diesel engine oil [SHPDO] though European in origin has emerged as a trend of relevance in the Indian context. This is not only due to the demands of commercial fleets for extended drain periods but also because of close similarities between Indian and European diesel engine designs. This has necessitated the development of an SHPDO with minimum performance conforming to CCMC D5 DB 228 3 and additional features to address the requirements of typical Indian operating conditions. This paper describes the selection of a superior SHPDO formulation using laboratory bench and performance engine tests, followed by field trials. Safe drain period of ∼ 40 000 kms has been established by statistical analysis of the field data generated in services typical of city and sub-urban operations.

This paper presents a special optical fiber technique which allows to measure temperatures in SI engines using the emission bands or respectively emission lines of the temperature radiation of diatomic molecules. The measurement technique enables the detection of average temperature in a small volume element. These temperatures are used to determine the local NO concentrations using the extended Zeldovich-mechanism. First, theoretical background of both temperature and NO-determination and measurement technique including optical fiber sensors are described. Finally, the temperature and NO dependence versus crank angle are presented and discussed at different combustion chamber locations for different engine operating conditions.