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In order to meet the viscosity requirements of multigrade engine oils, mineral and synthetic base oils of various viscosities and viscosity index improvers having various chemical compositions are used. As a consequence of both the viscosity-temperature behaviour of different base oils and the unique thickening effect of a given type of VI improver, the high- and low-temperature viscosity characteristics of a formulated oil are a function of the base-oil/VI-improver combination. The viscosity characteristics can be more or less optimized to meet the desired viscosity requirements. To provide acceptable rheological behaviour in practical formulations, it may be necessary to accept low-temperature performance that is less than optimum in order to achieve greater shear stability at a lower VI improver concentration.

Due to future directives of the European Union regarding fuel consumption and CO2 emissions the automotive industry is forced to develop new and unconventional technologies. These include for example stop-start-systems, cylinder deactivation or even reduction of the number of cylinders which however lead to unusual acoustical perceptions and customer complaints. Therefore, it is necessary to evaluate the sound character of engines with low numbers of cylinders (2 and 3 cylinders) and also the differences to the character of the more common 4-cylinder engines. Psychoacoustic parameters are used to describe and understand the differences. Based on the gained knowledge possible potentials for improvement can be derived in the future. The used data base consists of artificial head recordings of car interior noise according to defined driving conditions measured on the AVL test track. Naturally, there are more recordings available for 4-cylinder engines than for 2- and 3-cylinder engines.

Pilot injection gas engines are commonly used as large stationary engines. Often, the combustion is implemented as a dual-fuel strategy, which allows both mixed and diesel-only operation, based on a diesel engine architecture. The current research project focuses on the application of pilot injection in an engine based on gasoline components of the passenger car segment, which are more cost-effective than diesel components. The investigated strategy does not aim for a diesel-only combustion, hence only small liquid quantities are used for the main purpose of providing a strong, reliable ignition source for the natural gas charge. This approach is mainly driven to provide a reliable alternative to the high spark ignition energies required for high cylinder charge densities. When using such small liquid quantities, a standard common-rail diesel nozzle will apparently not be ideal regarding some general specifications.

Understanding the processes regarding fuel injection, vaporization and combustion during cold start is very important in order to reduce the HC-emission of gasoline engines. To learn more about the cold engine start-up process an experimental study on a 4.2 liter eight cylinder engine with gasoline direct injection was carried out. Parameters such as injection and ignition timing as well as the injection quantity were varied to get information about their effect on the combustion process and speed rise. Especially during engine run-up it is important to investigate every subsequent combustion. Therefore the engine was equipped with high pressure indication in each cylinder. The transient pressures and the instantaneous crankshaft speed of the engine were recorded by means of an indication system. Additionally a fast response flame ionization detector (FRFID) was applied to measure the transient HC-emissions during the first cycles of the engine.

Current commercial vehicles' engines are complex systems with multiple degrees of freedom. In conjunction with current emissions regulations manufacturers are forced to combine highly developed engines with complex aftertreatment systems. A comprehensive simulation model including the engine and aftertreatment system has been set up in order to study and optimize the overall system. The model uses a phenomenological spray combustion model to predict fuel consumption and NO emissions. In addition physical models for the material temperatures and the reaction kinetics were generated for the aftertreatment system. Steady state and transient measurements were used to calibrate the engine as well as the aftertreatment model. The aim for a system-level optimization was a reduction of fuel consumption while meeting emission standards.

The use of thermoplastics in various fields like aerospace, automotive, medical and packaging industries is growing day by day, due to their light weight and compactness. In some instances, the plastic components are required to be welded. In this research study, process parameters used for the ultrasonic welding of thermoplastics which produces highest weld strength for complex use in the above said applications is carried out. Also, the possibilities of welding dissimilar plastics are also tested. Tensile testing of above welded samples fabricated through injection moulding was carried out for all possible welds and the ultimate tensile strength was calculated in each case. Of all the welded specimens, at given parameters like weld time, weld pressure and energy director, it is observed that ultimate tensile strength of ABS (8.89 N/mm2) is highest.

The introduction of CO2-reduction technologies like Start-Stop or the Hybrid-Powertrain and the future emissions regulations require a detailed optimization of the engine start-up. The combustion concept development as well as the calibration of the ECU makes it necessary to carry out an explicit thermodynamic analysis of the combustion process during the start-up. As of today, the well-known thermodynamic analysis using in-cylinder pressure traces at stationary condition is transmitted to the highly dynamic engine start-up. Due to this approximation the current models for calculation of the transient wall heat fluxes by Woschni, Hohenberg and Bargende do not lead to desired results. But with a fraction of approximately 40 % of the burnt fuel energy, the wall heat is very important for the calculation of energy balance and for the combustion process analysis during start-up.

Fiber-reinforced polymer composites propose exceptional directional mechanical properties, and combining their advantages with the potential of 3D printing has resulted in many novel research fronts. Industries have started using 3D printed components which are rapidly replacing conventional material components in most of the industries. Carbon fiber reinforced Polylactic Acid (PLA) often finds its application in reasonably high loading conditions working at lesser speed like lightweight gears, spanners, nuts, and bolts. Wear reduction is an important factor that plays an important role in prolonging the component's life. Hence, it is crucial to optimize 3D printing parameters to get desired strength according to the application. The aim of this paper is to conduct the wear rate test on the Fused Deposition Modelled (FDM) printed carbon fiber reinforced PLA parts, to identify the optimum printing parameters which are crucial for wear reduction.

Experiments were conducted to study the effects of piston squish area on the performance, emissions and combustion characteristics of a Liquefied Petroleum Gas (LPG) fuelled lean burn Spark Ignition (SI) engine at a compression ratio of 10:1 under 25% throttle condition. A single cylinder diesel engine was modified to operate as LPG fuelled SI engine at a constant speed of 1500 rpm. The test was conducted at different squish areas of 25, 30, 35 and 40% on the total piston area at different equivalence ratios maintaining a constant squish velocity of 4 m/s. The ignition timing was set to MBT (Minimum advance for best Torque). It has been found that there is no significant change in lean limit in all the squish areas. An appreciable difference in brake power and brake thermal efficiency was noticed between equivalence ratios 0.7 and 0.9. The piston with 30% squish area showed good results followed by 25, 35 and 40%.

To comply with the upcoming emission regulations for non-road applications, especially the TIER 4 Final emission legislation, a significant reduction in particulate matters and nitrogen oxide emissions is necessary. An exhaust gas after-treatment system with a good performance helps to meet these requirements. The following paper focuses on the possibilities to reduce the nitrogen oxide emissions in exhaust gas after-treatment technology using selective catalytic reduction with AUS32. Using this technology and targeting a nitrogen oxide emission reduction of 90% the exhaust gas after-treatment system enables engine-out emissions of about 3 - 4 g/kWh nitrogen oxide. Considering an increase of only 5% reduction efficiency to 95%, a duplication of engine-out emissions could be acceptable for still meeting TIER 4 Final emission legislation.

Up to the present, the “W” portion of multigrade engine oils were classified only with regard to their low temperature startability by viscosity measurements at -18 C in the Cold Cranking Simulator. Because of the low shear rates encountered at the suction side of the oil pumps, the low temperature pumpability of the oils in the engine were not being considered. The investigations which were promoted by the DGMK were conducted to correlate the low-temperature pumpability of multigrade oils in a full-scale engine with suitable viscosity measurements and with results of tests in laboratory pumping rigs. Comparative measurements of viscosities were obtained with different viscometers. A critical shear rate of G = 50 s-1 was found for the borderline pumping conditions of the test engine. Good correlations were obtained between viscosity data of a rotational viscometer and engine pumping data.

A 2.0 l turbo charged gasoline engine with the mechanically fully variable mechanical valve train UniValve has been investigated on a test bed at the University of Kaiserslautern. First results of the mechanical behaviour, full load behaviour and fuel consumption at part load have been measured. These results are compared to the uncharged gasoline engine. In both cases the engines have been driven throttled and throttled free through the variable valve train. The dynamic behaviour of the turbocharger version has been investigated too. The only modification of the engine is the turbo charger, the valve train and the intake manifold hasn't been changed. The results have been compared with GT-Power simulations. The fuel consumption in the turbo charged mode at the map point 2,000 rpm/2bar could be improved up to 14 % through the throttle free load control vs. the throttled mode. The low end torque has been increased by 10 %.

Recent development in automobile industries has seen increased customer attention for good door slamming noise. One of the constituent which plays major role in building brand image of vehicle in terms of NVH performance is door slam noise quality. Hence it is very desirable to understand how different door elements radiate sound during a door-closing event and how to optimize a door structure to achieve specific sound target in order to ensure the door closing noise quality, NVH engineers needed to look at contributions from different door subsystems. The use of statistical tools like Six Sigma can further help them to ensure the consistency in results. This paper explains the systematic approach used to characterize different element of door which contributes to the overall door slam noise quality through QFD (Quality Function Deployment) and contribution analysis. The different mechanisms contributing to door slam noise were studied.

This article discusses new technologies and alloys in the field of ferrous and titanium alloy investment castings. It points out the advantages of proper management control and cites advantages of the investment casting process. There is a discussion on the subjects of tolerances, limitations, and new casting techniques. Finally a picture of what might be expected in the future for investment castings is presented.

In the past Airfreight Operators have minimized their investment risk by purchasing used passenger aircraft converted to carry cargo. Their investment decisions have been made on a short-term planning horizon without considering the long-term effects. This trend will soon reverse itself because of the sharp increase in fuel costs the “cutthroat” competition resulting from deregulation and most importantly the Economic Recovery Tax Act of 1981 that provides new tax incentives which favor the purchase of new aircraft over used equipment. The purpose of this paper is to describe the investment analysis and tools that have been recently developed at Lockheed-Georgia Company. These tools can be used to measure the economic worth and risk of alternative aircraft operating within the system of any given Air Cargo Operation. These investment decision models can be used by air cargo management as aids in making aircraft purchase decisions that will affect the future of their companies.

Inviscid flow fields have been computed for blunt axisymmetric shapes exposed to a hypersonic environment. A fully implicit scheme using a flux vector splitting technique was used to obtain a finite difference formulation. To increase computational efficiency, an approximate factorization scheme was used. Flow-field solutions were obtained for chemically reacting air using a decoupled approach. Flow fields were computed for blunted, flared shapes over a range of Mach numbers from 2 to 20.

Hard panel types of invisible passenger-side airbag (IPAB) door system must be designed with a weakened area such that the airbag will deploy through the Instrument Panel (IP) in the intended manner, with no flying debris at any required operating temperature. At the same time, there must be no cracking or sharp edges in the head impact test (ECE 21.01). If the advanced-airbag with the big difference between high and low deployment pressure ranges are applied to hard panel types of IPAB door system, it becomes more difficult to optimize the tearseam strength for satisfying deployment and head impact performance simultaneously. We introduced the ‘Operating Window’ idea from quality engineering to design the hard panel types of IPAB door applied to the advanced-airbag for optimal deployment and head impact performance. To accurately predict impact performance, it is important to characterize the strain rate.

Recently, the automotive industry has become more interested in knee injury, particularly in the application and development of knee airbag modules in vehicles to achieve a good rating during EuroNCAP and IIHS tests. Also, EuroNCAP and IIHS press the automotive industry to equip vehicles with knee airbag modules for occupant safety improvement in barrier tests. (1) Therefore, an invisible knee airbag module has been independently developed through design, simulation, static deployment tests and dynamic knee impact tests. A knee airbag module development process has been established and test results that were obtained from the development process are presented. Also, some design considerations for invisible knee airbag module development are discussed in this paper. A knee airbag module, which has been changed to match the IP lower panel shape and packaging specific vehicle environment, will be developed and produced in the near future.

Invisible Passenger-side Airbag (IPAB) door system must be designed with a weakened area such that the airbag will break through the Instrument Panel (IP) in the intended manner, with no flying debris at any temperature. At the same time, there must be no cracking or sharp edges at the head impact test (ECE 21.01). Needless to say, Head impact test must keep pace with the deployment test. In this paper, we suggested soft airbag door system that is integrally molded with a hard instrument panel by using Two-shot molding. First of all, we set up the design parameters of IPAB door for the optimal deployment and head impact performance by CAE analysis. And then we optimized the open-close time at each gate of the mold so that the soft and hard material could be integrally molded with the intended boundary. We could make the boundary of two materials more constant by controlling the open-close time of each gate with resin temperature sensor.

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