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A small 0.220 litre Petter IDI single cylinder engine was investigated over a 120 hour test period, consisting of 40 three hour test runs, with emission measurements and lubricating oil analysis every 20 hours for the same batch of fuel and lubrication oil. The particulates were analysed for the SOF and for the fuel/lubricant proportion using TGA. Fuel dilution of the lubricating oil was shown to increase uniformly with time and reached 10% after 120 hours, there was an associated decrease in the viscosity and increase in the lube oil fraction in the particulate SOF. Carbon contamination of the lubricating oil increased to 1.6% by mass over the 120 hour test period. The particulate emissions decreased initially and then increased after 50 hours, but the effect was no more than a 30% variation, mainly caused by variations in the carbon emissions. The motoring particulates were found to be low and dominated by vaporised lubricating oil.

Two Ford IDI passenger car diesel engines, 1.6 and 1.8 litres, were tested over a 100 hour lube oil ageing period with engine out emission samples every 15 hours. The 1.6 litre engine was tested with 5% EGR and the 1.8 litre engine with 15% EGR. Comparison was also made with previous work using an older Petter AA1 engine. The three engines had different dependencies of particulate emissions on the lube oil age. The 1.6 litre engine increased the particulates from 1 to 2.5 g/kg of fuel, whereas the 1.8 litre engine first decreased the particulate emissions from 3 to 1 g/kg over 50 hours of oil age and then they increased to 2 g/kg at 100 hours. This was similar to the previous work on the Petter AA1 engine, where the emissions first decreased and then increased as the oil aged. For the 1.8 litre engine the lube oil fraction of the VOF was high with fresh oil and decreased with time for the first 50 hours and then remained steady.

A test method suitable for evaluating the lubricant oil influence on surface ignition has been developed. The effects on this phenomenon of oils without additives, oils with ashless additives, and oils with organometallic additives have been studied. In addition, the influence of additive introduction rate in the combustion chamber has been investigated and evaluated.

A diesel generator set was used as a long term durability test for an exhaust particulate trap oxidizer system. The single trap (wall flow monolith) system was exposed to two 3000 hour tests. The tests included 20 minute engine cycles of varying speeds and loads, with complete monitoring of trap performance during loading and regeneration. The two tests differed in the type of lubricating oil and fuel used. The first test used a relatively high ash oil and regular sulfur fuel. The second test used an ashless oil and low sulfur fuel. The affects on the ceramic filter performance over the extended test times were dramatically different. The regular sulfur fuel and high ash of the first test resulted in a trap almost completely filled with ash. The low sulfur fuel and ashless oil of the second test had only 6% by mass of the ash collected in the previous test.

Maintaining a sufficiently porous structure in a wet friction material can be crucial to maintaining heat transfer from the bulk of the friction material into the fluid. Because of the lubricant flow from spinning plates and the fact that one side of the friction material is blocked by a steel core, porosity in the friction material must be maintained. Deposits directly from the oil, or transferred from the reaction plate, can accumulate in the friction material and/or seal surface porosity. When glaze forms on the assembly surface, a loss in friction coefficient will result. In this study, the proper selection of raw ingredients used in a friction material and the associated surface processing used in manufacturing the assembly will be shown to result in a material which has excellent friction stability and energy capacity compared to other wet friction materials.

This paper presents a theoretical model for prediction of forming limit diagram (FLD) in sheet metals. The theoretical procedure is based on the work of Marciniak and Kuczynski (known as the M-K model). The influence of material properties, such as anisotropy, strain hardening and strain rate sensitivity on the shape and level of the FLD are investigated. An initial non-uniformity in thickness of a sheet metal, which is commonly assumed as a basis for the prediction of limit strains in the biaxial stretching process, is considered here as a feature of the mathematical idealization of a complex process, rather than as a material imperfection existing in a real sheet metal.

It is assumed that braking system of a modern concept motor vehicle should be optimised with respect to a number of different parameters. There are cases where the brake performance under test conditions are significantly below designed (“nominal”) values. Such deviations are often attributed to the friction material characteristics, but there are also other possible causes such as mechanical losses in the brake itself. Contribution to the allocation of mechanical losses in drum brakes and quantification of their influence on the brake performance and braking force distribution is presented in this article. It was shown that there is a significant influence of mechanical losses on the drum brake performance, especially in unladen vehicles, vehicles equipped with highly sensitive brakes (high brake factor values) and in cases where vehicle is braked on low friction roads.

For over 40 years, NASA has been putting humans safely into space in part by minimizing microbial risks to crew members. Success of the program to minimize such risks has resulted from a combination of engineering and design controls as well as active monitoring of the crew, food, water, hardware, and spacecraft interior. The evolution of engineering and design controls is exemplified by the implementation of HEPA filters for air treatment, antimicrobial surface materials, and the disinfection regimen currently used on board the International Space Station. Data from spaceflight missions confirm the effectiveness of current measures; however, fluctuations in microbial concentrations and trends in contamination events suggest the need for continued diligence in monitoring and evaluation as well as further improvements in engineering systems. The knowledge of microbial controls and monitoring from assessments of past missions will be critical in driving the design of future spacecraft.

Influence of Microcomputer Technology on Propulsion Management Systems The rapid pace of digital electronic technology over the last decade has made practical engine-mounted electronic fuel controls for commercial transports. The current status of digital fuel control technology is presented along with a projection of future systems. The computing power of modern processors makes possible the implementation of extremely complex control modes at modest cost. The ease of using two or more machines in parallel and the capability of the digital computer to test the authenticity of input data leads to interesting techniques for enhancing airworthiness, dispatchability, and maintainability.

The microstructure of the multiphase PC/SAN blend system is shown to be important for engineering applications in both design and processing. Structural characterization can be achieved by direct microscopic investigations as well as by inferences obtained from physical property assessment and simple mechanical models.

In all structures there are several reasons why misalignment can occur at a bearing. This is especially true with large structures such as off-highway equipment of all types, agricultural tractors and implements and roadway vehicles. Equipment of these types will see more bearing alignment problems than smaller automobiles, garden equipment and machine tools. Misalignments can be attributed to distortion in welded units. Efforts to line bore long distances and simply the accumulation of tolerances on several parts also cause alignment problems. Even if the designer makes diligent efforts to reduce tolerancing and manufacturing inaccuracies, the bearing surface will still be subjected to structural misalignment simply due to load application even though not considered overloading. All of these misalignment causes can occur individually or simultantously subsequently causing bearing overloading to shorten bearing life or crush the bearing.

An experimental technique was used in evaluating the influence of mixture preparation in the intake port on the performance of a steady-operating, 1.9L Ford engine. The fuel preparation components investigated in this study were vapor, droplets, and liquid streams. Engine performance was evaluated in terms of in-cylinder pressure and exhaust gas emissions. Fuel vapor, small droplets (Sauter mean diameter less than 10 mm), and liquid streams were produced and varied in a carefully-controlled mixture preparation system, which delivered an air/fuel mixture to an engine test cylinder. The air/fuel mixture was saturated prior to delivery to the cylinder so as to stabilize the fuel preparation components for study. Also, incorporated in the preparation system were devices for physically measuring the amount of fuel in the form of droplets and liquid streams.

Exhaust-port hydrocarbon (HC) concentration measurements were made using a Fast Response Flame Ionization Detector (FRFID) in order to investigate the mechanisms by which mixture preparation affects engine-out HC emissions. The mixture preparation was varied by: (a) using fuels of different volatility, (b) varying the injection timing, and (c) decreasing the coolant temperature. The observed increases in HC emissions which resulted from lowering the coolant temperature or employing open valve injection are primarily attributed to the resulting increase in the in-cylinder liquid fuel, which is deposited mainly on the cylinder walls and in the piston crevices. The HC attributed to the liquid fuel deposited on cylinder walls exit the engine cylinder roughly in the middle of the exhaust process. On the other hand, the HC attributed to the liquid fuel stored in the piston crevices, and which represent the largest fraction, exit the cylinder during the end of the exhaust process.

Race cars undergo very quick ride height changes on the track, which are induced by breaking, acceleration, cornering, as well as bumps on the track. It has recently been shown in wind tunnel tests that these quick changes in model attitude can lead to astonishingly large hysteresis effects on the aerodynamic coefficients. In order to verify whether such effects may be relevant to the overall performance of a car, aerodynamic data from wind tunnel tests with a moving model was fed into a vehicle dynamics simulation program. Relevant changes in estimated car performance on straight as well as on curved tracks are reported.

The motorcycle was designed as a means of commuting for a rider and pillion. In today's time usage of two wheelers is not limited to commuting purpose but has extended to load carrying applications; particularly in South Asian countries. This change in the usage of the motorcycle leads to a difference in its dynamic behavior. To explore the reasons for this difference, a detailed and comprehensive parametric study of key vehicle parameters for different usage patterns of the motorcycle was done. With the help of a Multibody code (MSC.ADAMS), a series of motorcycle handling simulations were carried out where the motorcycle is made to undergo various maneuvers such as slalom, lane change and steady state cornering. Well established handling indices are used to analyze the simulation data and vehicle parameters are then optimized for arriving at the best possible vehicle configuration which would result in a vehicle with safe and predictable behavior irrespective of the usage pattern.

The goal of vibration testing is to obtain a good representation of the mode shapes and associated natural frequencies of a mechanical system. Often the test setups for vehicles are designed to approximate free-free boundary conditions. Ideally the stiffness and mass of the actual mounting system should be attached so that the measured mode shapes and frequencies of the test structure are unchanged. In practice, this is not possible and the quantitative influence of mounting stiffness on measured frequencies is of interest. Two models have been analyzed and will be discussed in this paper. First, a model having one vibrational degree of freedom was chosen because it is the easiest system to analyze and because it represents an individual uncoupled mode of a multiple degree-of-freedom system. Second, a whole car was analyzed to provide a realistic assessment of the influence of mounting stiffness on a vehicle vibration test.

As new designs of diesel engine, which emit less noise, are evolved to meet increasingly stringent noise legislation, noise from diesel fuel injection equipment could become a significant proportion of the total noise from the engine. Quieter fuel injection pumps are being produced for such engines by Lucas CAV, however their potential will not be realised unless special care is taken in the design of pump drive and mounting brackets. Impacts from the sudden take-up of backlash in the drive to the pump, and vibration of the engine surfaces to which the pump is secured, can increase pump-radiated noise considerably.

In the past, muscle activation has been identified as having an important effect on the head-neck response in dynamic conditions. However, this claim has been largely based on global observations, and not by accurate analysis. In this study, the influence of muscle activation on the head-neck response is investigated by mathematical modeling. The detailed mathematical head-neck model presented by De Jager is improved by modeling the neck muscles in more detail. A multi-segment muscle description is applied in which the muscles curve around the vertebrae, resulting in realistic muscle lines of action. The model is validated with human volunteer responses to frontal and lateral impact at several severities. The model response with maximum muscle activation to high severity frontal and lateral impacts agrees well with volunteer responses, whereas a submaximum activation level or a larger reflex delay provides better results for the low severity impacts.

In this work the influence of NO on combustion phasing has been studied experimentally in a single cylinder HCCI engine. A isooctane/n-heptane blend (PRF), a toluene/n-heptane mixture (TRF) and a full boiling range gasoline were tested at two different operating conditions with NO concentrations ranging from 4 up to 476 ppm in the fresh intake air. All three fuels had the same RON of 84. The first operating condition had a high intake pressure (2 bar absolute) and low intake temperature (40 °C), where low temperature chemistry is relatively prominent. The other operating condition had a high intake temperature (100 °C) and atmospheric intake pressure with significantly lower cool flame reactivity. Additionally the effect of NO at two different engine speeds, 900 and 1200 rpm were studied. The combustion phasing, represented by CA50 was advanced up to 12.5 CAD by the influence of NO.

Variable composition of natural gas depending on the gas source causes variable ignition and combustion properties when used as fuel in internal combustion engines. Ignition and combustion problems lead to reduced efficiency, increased levels of emissions, as well as increased mechanical and thermal loads on engine components. The main objective of this study is to investigate the influence of natural gas composition on ignition properties in a direct injection hot surface assisted compression ignition engine. Previous investigations have shown that ignition of methane require hot surface temperature in the range of 1200-1400 K in order to obtain an ignition delay within 2 milliseconds. Pure methane and several natural gas mixtures have been tested under various conditions in a constant volume combustion bomb and in a test engine. Ignition delay and cycle to cycle variations are used to compare the combustion qualities of the different gas.