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Of the injuries sustained by belted rear occupants in a frontal collision event in Japan, the neck and the head are the regions of the body most likely to be injured, while children and female occupants are accounting forthe highest rate of injuries. For the purpose of reducing rear seat occupant injuries, the occurrence mechanism of neck and head injuries is clarified by sled tests with the current rear seat belt system. When a high load is applied to the occupant via the seat belt, the occupant experiences sudden deceleration of the chest, resulting in a great relative velocity difference between the head and the chest. This causes injury to the occupant's neck and head. To reduce occupant injuries, therefore, it is important to minimize the relative velocity difference by control of belt load. This paper proposes the concept of optimal belt load control and summarizes parameter study results that have been conducted to verify the validity of the concept using occupant simulation, MADYMO, ranging from 6-year-old dummy (hereinafter "6Yo"), AF05, and AM50 to AM95. Also, in this paper is mentioned the optimal belt control characteristics found through the study.

This paper reviews the state of the art of CAE simulation and analysis methods on disc brake squeal. It covers complex modes analysis, transient analysis, parametrical analysis, and operational simulation. The advantages and limitations of each analysis method are discussed. This review can help analysts to choose right methods and decide new lines of method development. For completeness, analytic methods dealing with continuum models are also briefly covered. This review was made from those papers that the authors are familiar with. It is not meant to be all-inclusive even though the best possible effort has been attempted.

This paper describes how the decision of linear elastic Young’s Modulus and other properties of airbag cushion fabric are difficult mainly because of the non-linearity of stress-strain curve of the cushion fabric. Especially for the tensile test of cushion fabric, the different test methods add complexity in determining proper linear elastic modulus. Poisson’s ratio has been generally assumed as a mean value of steel’s one rubber’s one in the modeling of airbag cushion in previous researchers. In this paper, airbag droptower test and simulation were performed for example to find the proper material properties of airbag cushion fabric such as Young’s Modulus, Poisson Ratio, Permeability and Shear Modulus. By modeling the textile cushion fabric material type as isotropic and orthotropic material with linear and nonlinear membrane element, the material properties of cushion fabric with which numerical analysis shows good agreements with droptower test were found. I-SIGHT optimization program has been applied in optimization phase. The DOE (Design Of Experiment) analysis results of cushion fabric material properties are presented.

In view of tight emission standards, injection strategies to reduce raw HC-emissions during the cold starting of port fuel injected engines are evaluated in this study. The relevance of spray targeting and atomization is outlined in the first part of this paper. The foundation and performance of different injector concepts with respect to spray characteristics are discussed. Laboratory experiments demonstrate that concepts relying on auxiliary energy, such as air-assistance, fuel heating and injection at elevated system pressures, are capable of producing spray droplet sizes in the SMD-range of 25μm. For future injection strategies aimed at the compliance of SULEV emission levels, this target value is considered to be essential. In the second part of this paper, emission tests of selected injector concepts are carried out using a V6-3.21 ULEV engine operated both in a vehicle and on a test bench. In this context, the relevance of an optimized start calibration as well as defining engine operating boundary conditions is discussed. Improving the fuel flow inside current injector designs already yields a 20-30% reduction of raw HC-emissions during cold starting. Significant reductions in the range of 40-50% are achieved by means of heated-tip injectors and fuel injection at elevated system pressures. Additionally, an FTP75 test series for selected concepts is presented.

This paper discusses how sled testing is one of the most important test methods for the evaluation of vehicles interior with respect to crash safety. This method allows one to simulate real crash conditions without destroying the vehicle structure. In addition to conventional sleds which are accelerated smoothly using a bungee cord or other device and then impact a deformation element, catapult sled types act in a reverse mode. The sled is thus accelerated for approximately 100 ms to the impact speed and then smoothly decelerated. To ensure good correlation with the full-scale crash test an accurate modeling of the vehicles crash pulse must be guaranteed. Catapult-type sleds guarantee, that the sled will not move before the pulse starts. Therefore well-defined initial conditions especially regarding dummy positioning can be guaranteed. While conventional catapult-type sleds mainly work on hydraulic or pneumatic modulation of the pulse. Hyper-G combines a simple pneumatic spring with a hydraulic brake directly acting on the ram. While the pneumatic air spring provides a rather constant force, the pulse is modeled by varying the brake force. As only little hydraulic flows are required to control the brake, standard valves with very fast response and small through flows can be used. In this way it was possible to use a closed-loop system which automatically compensates for dynamic masses. This paper demonstrates the principle functionality, safety aspects, handling and performance of this new system.

The paper illustrates how probabilistic physics-based models can be used for risk-based condition assessment and life prediction of aircraft jet engines, including the uncertainties in maintenance activities. Although this paper focuses on engines, the proposed approach can be extended elsewhere. Probabilistic modeling includes all significant uncertainties that affect engine reliability, such as flight conditions, loading history, manufacturing deviations, material properties and behavior under random loading and maintenance activities. Maintenance uncertainties include those related to NDI techniques and operator’s skills. The paper shows the uncertainty effects of different NDI techniques, maintenance intervals, operator skills, etc. on the engine reliability. Unscheduled maintenance rates are computed for given a maintenance schedule.

This paper discusses parametric optimization of the cushion shape of passenger side airbag, which has three-dimensional and vehicle interior parts dependent shape and how it is very important to define the design variables to make the ranges of variables, and to set up the design process. In this paper, the considerations of cushion design of mid-mounted passenger airbag are presented. Considered design variables are size, width of cushion, location, width, the number of tether, and size of vent hole. By using orthogonal array, in-position NCAP simulation is performed within the ranges of given control levels. Also, the relationships among design variables are analyzed to help the design of airbag cushion.

The paper presents the results of a down-sizing concept implicating gasoline direct injection, which is applied to a four-stroke four-valve SI engine with a displacement of 500 ccm per cylinder. The typical features of a down sized engine such as a high level of engine speed, high power density at low fuel consumption and a low level of pollutant emission form the main targets of this study. Numerical models of the process stages have been developed in 1D and 3D CFD codes. The accurateness of the models has been proved using experimental results. The main work consisted on the application of a direct injection system to the engine. The compact engine design and the high compression ratio have been maintained resulting in a combustion chamber design without any cavities or bowls. To obtain accurate results, the simulation work has been carried out using two different CFD-codes (FIRE and VECTIS); the results have been analyzed and compared. Following optimization parameters have been taken into account: injector and spark plug location, injection timing and duration as well as intake duct design. The optimization results in terms of mixture formation by direct injection and the combustion, are presented in the paper. Complete Paper available under: http://www.sae.org/servlets/productDetail?PRO D_TYP=PAPER&PROD_CD=2003-01-0541

This paper describes how the future characteristics of building a headlamp with white LED’s could be possible. The cost of LEDs’ lumens, their low luminance and their huge difference with traditional bulbs as light sources make new optical designs necessary. Projector modules appear to be the best basis for these new systems. Efficient versions, especially fitted to LEDs that have been recently designed and tested are present in this paper.

Changing safety regulations have prompted airbag manufacturers and automakers to continually create and develop new types of airbag systems. These devices are used to afford protection to vehicle occupants in the event of a collision. Recently, the National Highway Traffic Safety Administration (NHTSA) established new requirements for airbags under Federal Motor Vehicle Safety Standard (FMVSS) 208 - Occupant Crash Protection and FMVSS 201U - Upper Interior Head Impact Protection. This paper will discuss improved testing equipment and methodologies in the areas of component and full-vehicle testing involving various types of airbags. This work has been the direct result of numerous airbag system development projects currently underway. The types of new equipment and test methodologies for airbags that will be discussed in this paper include: - Airbag Deployment Chamber for Static Airbag Deployment; - Synchronized Airbag Deployment/Dummy Impact Testing; - FMVSS 201U Targeting Including Side Curtain Airbag Zone Determination; - Side Pole/Curtain Airbag Development Sled Simulation Testing; - FMVSS 208 Out-of-Position (OOP) Static Airbag Deployment Testing. This paper will provide a broader understanding of the new developments in airbag design, testing, and validation. This paper will also provide information regarding the latest changes to the federal safety regulations with respect to advanced airbag devices and a summary of required testing. It will also offer details regarding the new testing equipment and test methodologies available today.

An experimentally derived map of the engine volumetric efficiency is usually employed to control the A/F ratio in a SI-ICE. In the case of a variable valve timing (WT) engine, a different efficiency map must be consideredat each camshaft position, as a consequence of the influence on the air flow exerted by the actual position of the intake/exhaust camshaft. In this paper, an attempt is reported to theoretically derive a correlation of the volumetric efficiency as a function of engine speed, manifold absolute pressure, and camshaft position. The correlation is not based on experimental data but on the results of a one-dimensional simulation model (1 Dime code) developed at DIME. An extensive validation of the 1D model is preliminary reported in the first part of the paper. The procedure is developed with reference to a four-cylinder, SI engine, equipped with a phased intake and exhaust WT device. The latter includes a "slider" which deactivates a tumble-flow inducing port for burning speed enhancement at part-load. The derived correlation also accounts for the variations of ambient conditions and can be directly included within the classical strategies for A/F Ratio control, programmed inside the ECU. The whole methodology allows to greatly reduce the experimental efforts required to fully characterize the WT engine and to develop its control logic.

This paper presents efforts made on the computational modeling and simulation of our-of-position occupant-airbag interaction. The airbag has been modeled using the finite element method with LSDYNA. The investigation in this paper shows that the integration of an FE airbag model with an ATB occupant model is a feasible and effective way of modeling and simulating the biodynamics of an occupant-airbag system. It takes the advantages of the detailed modeling of the airbag provided by FE and the efficient modeling of the occupant provided by ATB. The use of the integrated model in the simulations of unbelted occupant sled impact and static OOP deployment impact has produced fairly realistic demonstrations of the kinematical responses of the occupant.

One of the attractive characteristics of the spectacle of the 24 Hours of LeMans is the technical variety of engine type and size solutions competing for the overall win. The question whether the turbocharging solution offers sufficient advantages in any racing application depends entirely on the technical restrictions governing that application. In the absence of technical restrictions on turbocharged engine output, obviously turbocharging offers significant advantages in outright power capability, as well as power/weight and power/size ratios. But what about the situation where the technical restrictions placed on turbocharged engines are carefully calculated to marginalize any peak power advantage and make all powerplant peak outputs essentially equal? Such is the case concerning the technical regulations currently in force (2002) at the 24 Hours of LeMans, sanctioned by the Automobile Club de l’Ouest (the ACO). Using a carefully calculated combination of restrictions on maximum airflow by use of air inlet restrictors on all engines plus boost limits on turbocharged engines, the ACO has created a technical formula that effectively gives all engines in the LMP900 and GTP categories similar maximum air massflow capability and therefore similar maximum power output potential, regardless of displacement, engine layout or induction method. (Ref 1). In this situation, what advantages are left for turbocharging to offer? There are several well understood ones. Smaller displacement gives reduced internal friction losses which contribute to minimizing fuel consumption. A smaller, lighter engine package allows the possibility for 1) vehicle handling improvements due to lower center of gravity and lower gross vehicle weight; and 2) body aerodynamic improvements due to smaller engine covers that can reduce drag and improve rear wing performance by reducing turbulence in front of the rear wing. This paper will not address these well understood advantages but instead address perhaps the most misunderstood, yet perhaps the most significant advantage for this type of racing, durability. Turbocharged racing engines offer the possibility to achieve equal performance with significantly lower internal inertia loading because of smaller and therefore lighter reciprocating components operating at lower speeds. This can be achieved without the need for high cylinder counts or exotic and costly low-density supermaterials to reduce the reciprocating mass per cylinder in order to reduce the maximum connecting rod tensile load. This paper will compare the effects of reciprocating mass per cylinder and engine speed on connecting rod load reversal cycles for typical engines of varying displacement, cylinder count and induction type to explain why turbocharged engines have demonstrated vastly superior durability results in the LMP900 and GTP classes at LeMans in recent years.

In order to meet the Euro V heavy-duty diesel emission standard legislation limits, a diesel engine can be optimized by internal means to give low particulate emissions and lower fuel consumption. These modifications of the engine lead inevitably to higher NOx emissions due to the NOx/PM trade off. An efficient Urea SCR after-treatment system is then able to reduce the higher NOx emission to below the Euro V 2.0g/kWh legislation limit. This paper presents tests made on a PM optimized 12 liter heavy-duty diesel engine together with a urea SCR after-treatment system. The optimized engine had engine out particulate emissions of about 0.04 g/kWh and NOx emissions of 9 g/kWh for the ESC and 8,5 g/kWh for the ETC. The fuel consumption of the optimized engine was 194 g/kWh for the ESC and 198 g/kWh for the ETC as compared to state of the art Euro III engines of typically 210 g/kWh for the ESC, giving significant fuel savings of 7.5 %. Combining the engine with a 20 liter 300-cpsi SCR catalyst, catalyst volume to cylinder ratio of 1.7, the particulate emissions dropped to 0.017 g/kWh for the ESC and 0.020 for the ETC. Particle size measurements also showed a decrease in the number of fine particles. With a urea injection corresponding to about 8-9% of the fuel flow the NOx emissions were reduced to 1.4 g/kWh for the ESC and 1.5g/kWh for the ETC with low ammonia slip. These reductions correspond to a NOx conversion of 84 % and 82% for the ESC and ETC respectively. Thus the optimized engine combined with the urea SCR after-treatment system was compliant with the Euro V emission limits. INTRODUCTION In order to comply with the Euro V regulations for heavyduty diesel engines due in 2008, both the NOx and particulate emissions must be greatly reduced for today’s state of the art diesel engines. The regulations of 2008, namely 2.0 g/kWh NOx and 0.02 g/kWh particulates for the ESC and 0.03 g/kWh for the ETC driving cycles, cannot be achieved solely by engine management or improved engines, rather some sort of aftertreatment must be used. A preferred solution to comply with the Euro V emission limits is to optimize a diesel engine by internal means to give very low particulate emissions and considerably lower fuel consumption [1]. Due to the NOx/PM trade-off for diesel engines this will lead to higher NOx emissions, from Euro III levels of 5-6 g/kWh to 8-10 g/kWh, that have to be reduced with an efficient NOx aftertreatment system below the 2.0 g/kWh limit, preferably Urea-SCR. The Urea SCR systems have been shown to be both very efficient and durable in vehicle applications [2,3,4,5,6]. The higher NOx emission of the optimized engine therefore requires the Urea SCR system to have a high NOx conversion efficiency of about 80-85%. The combination of the optimized engine and Urea SCR system eliminates the need for a particulate filter to comply with Euro V emissions leading to a lower pressure drop of the exhaust system and also less complexity of the total system. Furthermore the significant fuel savings of the optimized engine compared to a standard Euro III engine could give a payback time for the optimized engine and the SCR system depending on the urea price and the application as to make the concept commercially interesting even prior to the legislation limits. This concept could also be a serious candidate for the Euro IV legislation (NOx limit of 3.5 g/kWh and particulates the same as Euro V). The optimized engine and SCR concept has an even greater fuel saving compared to a concept of a standard Euro III engine with EGR and particulate filter. EGR increases the fuel consumption of the engine and the addition of the particulate trap increases the fuel consumption further by increasing the pressure drop giving the combination of the optimized engine and Urea SCR system an even greater fuel consumption advantage. The purpose of this work was to demonstrate a PM and fuel optimized heavy-duty diesel engine and Urea SCR concept able to comply with the Euro V legislation emission limits. The total work consisted of 3 parts: • SCR catalyst optimization and selection [7] • Engine optimization • Combination of the optimized engine with the chosen SCR system. In previous work the catalyst selection to achieve a high NOx conversion above 80% with ammonia slip less than 10 ppm and development of a novel Urea SCR injection system were discussed [7]. This present paper deals with the optimization work on the engine, performance of the optimized engine, final selection of catalyst and the performance of the combination of the PM and fuel optimized engine with the efficient Urea-SCR system. The optimization targets of the engine optimization were to achieve low soot emissions (i.e. carbon particulates less than 0.010/0.015 g/kWh in ESC/ETC test) by internal means while maintaining very low fuel consumption at engine-out NOx emissions of 8 to 10 g/kWh in the ESC test.

Advanced projects envisage multiple EVAs on the planetary surface and great distances to be covered by EVA astronauts during manned Mars missions. Astronauts’ egress with special Martian EVA space suits on can be provided only through the landing module/spacecraft airlock. To move over the planet, astronauts are expected both to walk and use a planetary rover (Martian rover). To make EVA activities on the planetary surface successful, an optimized concept for space suit attachment both to the airlock and Martian rover should be developed. The paper considers concept options of the planetary space suit (PSS)/airlock and PSS/Martian rover mechanical interfaces based on patent information study and analysis of development, test and operation data for the EVA space suits. The paper proposes an option of the concept that, in the authors’ viewpoint, fulfills in the best way the following tasks: astronauts’ unassisted capability to fulfill all airlock procedures, space vehicle ingress/egress, Martian rover ingress/egress and control of driving. The selected interface concept is based on the space suit design with a hard upper torso (HUT) and a rear entry hatch. The concept provides for HUT-mounted attachment points and their mating fasteners located on the airlock wall and on the Martian rover. Using the same interfaces, the suited astronaut can be attached to the Martian rover working station and to the airlock. There are no usual seats on the Martian rover, consequently, there is no need to sit and stand in the rover. Ingress to and egress from the Martian rover become comfortable. To have a rest, an astronaut can “sit” inside the suit. This paper presents interfaces’ design concepts and application method.

This paper describes the New Shuttle Orbiter's Multi- Purpose Logistics Modulo (MPLM) Cargo Heat Exchanger (HX) and associated MPLM cooling system. This paper presents Heat Exchanger (HX) design and performance characteristics of the system.

This paper studies the energy-saving adaptive robust precision motion control of a single-rod hydraulic cylinder through the use of programmable valves. The programmable valves used in this study is a unique combination of five proportional cartridge valves connected in such a way that the meter-in and meter-out flows can be independently controlled by four of the valves as well as a true cross port flow controlled by the fifth valve. The programmable valves decouple the meter-in and meter-out flows providing tremendous flexibility to control the cylinder motion while decreasing the energy usage by utilizing the potential and kinetic energy of the load. This paper investigates the different working conditions of the programmable valves and proposes a simple yet effective way to use the programmable valves based on the desired states and current states.

Copyright © 2002 SAE International. This paper is posted on this site with permission from SAE International. Further use of this paper is not permitted without permission from SAE Controlled Auto-Ignition (CAI) combustion was realised in a production type 4-stroke 4-cylinder gasoline engine without intake charge heating or increasing compression ratio. The CAI engine operation was achieved using substantially standard components modified only in camshafts to restrict the gas exchange process The engine could be operated with CAI combustion within a range of load (0.5 to 4 bar BMEP) and speed (1000 to 3500 rpm). Significant reductions in both specific fuel consumption and CO emissions were found. The reduction in NOx emission was more than 93% across the whole CAI range. Though unburned hydrocarbons were higher under the CAI engine operation. In order to evaluate the potential of the CAI combustion technology, the European NEDC driving cycle vehicle simulation was carried out for two identical vehicles powered by a SI engine and a CAI/SI hybrid engine, respectively. The simulation results showed only moderate improvement in fuel economy and exhaust emissions because of low utilisation of CAI during the drive cycle. In order to take full advantage of the CAI combustion technology, detailed analyses were carried out on the engine’s performance, heat release and combustion characteristics, emissions and the effect of gas exchange processes. These analyses showed that the engine’s performance and emissions were mainly affected by the trapped residual fractions and residual temperature. In addition, the backflow was found to affect the combustion and emission as well.

The paper presents a GDI concept applied to a fourstroke four-valve single cylinder engine in base of the original “crevice-like” combustion chamber of the basic engine with external mixture formation. For such application both, an adapted shape of injection rate as well as a good correlation of location and timing between injection and spark is requested. The shape of injection rate is adapted in base of a pressure pulse injection system. The paper presents the special features of the system conceived for this aim, as well as the results for different locations of injector and spark plug. The best results in terms of bmep, bsfc and pollutant emissions are obtained with a twin spark configuration. The mixture formation and combustion particularities of this concept are analyzed going from the experimental results at the engine test bench for full and part-load in condition of widely unthrottled operation. Complete paper available under: http://www.sae.org/servlets/productDetail?PROD_TYP= PAPER&PROD_CD=2002-01-0833

The ultimate goal in the numerical simulation of automotive catalytic converters is the prediction of exhaust gas emissions as function of time for varying inlet conditions, i.e. the simulation of a driving cycle. Such a simulation must include the calculation of the transient three-dimensional temperature-field of the monolithic solid structure of the converter, which results from a complex interaction between a variety of physical and chemical processes such as the gaseous flow field through the monolith channels, the catalytic reactions, gaseous and solid heat transport, and heat transfer to the ambience. This paper will discuss the application of the newly developed CFD-code DETCHEM MONOLITH for the numerical simulation of the transient behavior of three-way catalytic converters that have a monolithic structure. The code combines the two-dimensional simulations of the reactive flows in a representative number of monolith channels with a transient simulation of the three-dimensional temperature field of the solid structure of the converter including insulation and canning. The chemical reactions are modeled by a multi-step heterogeneous reaction mechanism, which is based on the elementary processes on the platinum and rhodium catalysts used. The integration over the chemical conversion in the single channels leads to the total conversion in the converter as function of time. This paper presents a numerical simulation of the startup phase of an automotive catalytic converter for temporally varying inlet conditions. The variation of the temperature distribution in the solid structure and in the single channels as well as the species profiles are described. The numerically predicted time-dependent conversion of the combustion pollutants is compared with experimental data. The potentials and limitations of the models and computational tools are discussed.

The optimization of diesel engine performance and emissions can be achieved through a better understanding of the in-cylinder combustion process. Advanced non-intrusive optical techniques are providing new tools for investigating the thermo-fluid dynamics processes as well as they are contributing to develop predictive models for DI diesel combustion. High-speed images of spray and flame evolution as well as UV-visible chemiluminescence measurements were carried out in an optical 0.5-liter, single-cylinder, four-stroke, direct- injection diesel engine equipped with a prototype four valves cylinder head and a fully flexible CR injection system. In order to evaluate the effect of different injection strategies on the combustion process, measurements were performed varying injection parameters. The ignition location and time were individuated by combustion visualization and detection of radical species, obtained by chemiluminescence measurements. The spectral features of broadband flame emission characterized soot formation and its evolution.

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We have developed a methodology for predicting combustion and emissions in a Homogeneous Charge Compression Ignition (HCCI) Engine. This methodology combines a detailed fluid mechanics code with a detailed chemical kinetics code. Instead of directly linking the two codes, which would require an extremely long computational time, the methodology consists of first running the fluid mechanics code to obtain temperature profiles as a function of time. These temperature profiles are then used as input to a multi-zone chemical kinetics code. The advantage of this procedure is that a small number of zones (10) is enough to obtain accurate results. This procedure achieves the benefits of linking the fluid mechanics and the chemical kinetics codes with a great reduction in the computational effort, to a level that can be handled with current computers. The success of this procedure is in large part a consequence of the fact that for much of the compression stroke the chemistry is inactive and thus has little influence on fluid mechanics and heat transfer. Then, when chemistry is active, combustion is rather sudden, leaving little time for interaction between chemistry and fluid mixing and heat transfer. This sequential methodology has been capable of explaining the mainmore » characteristics of HCCI combustion that have been observed in experiments. In this paper, we use our model to explore an HCCI engine running on propane. The paper compares experimental and numerical pressure traces, heat release rates, and hydrocarbon and carbon monoxide emissions. The results show an excellent agreement, even in parameters that are difficult to predict, such as chemical heat release rates. Carbon monoxide emissions are reasonably well predicted, even though it is intrinsically difficult to make good predictions of CO emissions in HCCI engines. The paper includes a sensitivity study on the effect of the heat transfer correlation on the results of the analysis. Importantly, the paper also shows a numerical study on how parameters such as swirl rate, crevices and ceramic walls could help in reducing HC and CO emissions from HCCI engines.« less

This paper describes two advanced electronic fuel injection systems for small vehicles which have recently become commercially available. Both systems have been designed and developed by the authors’ organisation. One of the two systems (‘aSDI’) has been designed and developed for 2-stroke engines and the other (‘SePI’) for 4-stroke engines. Both systems are intended for application on small vehicles fitted with small 1 – 2 cylinder gasoline engines of displacement 50 – 250 cm per cylinder. Typical examples of such small vehicles are: ATV’s (All Terrain Vehicles), auto-rickshaws, motorcycles, motorscooters and mopeds. Fuel consumption and emissions results from both systems are presented, and in both cases it is shown that engine-out exhaust emissions meet current and future limits in Europe, India and Taiwan, without the need for exhaust after-treatment. It is also shown that both systems offer significant fuel savings relative to otherwise-equivalent, carburetted baseline vehicles. Other important benefits of these systems which are discussed in this paper are improved cold start and improved driveability. The paper also includes a short overview of the performance and cost implications of both systems relative to alternative emissions control methods. 1 For reasons of convenience, these types of vehicles will be referred to collectively as ‘small vehicles’ in this paper.

Nonevaporating diesel sprays from an Electronic Common-Rail system are investigated by two different laser light techniques at room temperature within vessels at both ambient and high pressures. Injection is performed by using single-hole injectors of mini-sac type with nozzle orifices 0.18 and 0.22 mm, which operate at injection pressures in the range 40 to 120 MPa. The fuel used is the standard ISO 4113. The densities of ambient gas (nitrogen) are varied in the constant volume vessel within the range 1.2 \md 58.4 kg/m\u3. Two different laser diagnostics are used to infer quantitative information on jet properties. The first is the light Extinction Ratio (ER) method, which is applied at wavelengths 632.8 nm and 832 nm in correspondence of the early instants (\mA200\md800 \gms) after the end of the liquid injection to infer the average droplet diameter and the number concentration along the line-of-sight. The second experimental technique is the Laser Doppler Anemometry (LDA). The droplet 2D velocity fields are measured as function of the radial coordinate and distance from the nozzle. A methodology is proposed to precisely locate the spray contour from the measurements of the 2D velocity distributions on the spray periphery region.

Author(s): Hauer, Karl-Heinz; Moore, Robert M; Ramaswamy, Sitaram | Abstract: Presented at the Future Transportation Technology Conference a Exposition, Costa Mesa, CASession: Alternative Fuels a Fuel CellsThis work focuses on the algorithms to simulate and analyze the characteristics of an indirect methanol fuel cell vehicle. The individual components of the electric drive train including transmission, the vehicle properties, such as drag, frontal area, wheel inertia etc., and the fuel cell system are modeled in a dynamic manner. Further the interaction between the individual components and a simple driver model is described. The algorithms are coded using the simulation tool Matlab/Simulink.The simulation tool is strictly set up in a modular form allowing modifications of individual component characteristics or control algorithms without the need to change the remainder of the model. For the benefit of a more in depth discussion of the applied algorithms and the setup of the model this paper focuses solely on the case of an Indirect Methanol Fuel Cell Vehicle (IMFCV) with steam reformer and without any additional energy storage. Other papers expanding this initial work and discussing various cases of hybridization (batteries, ultra capacitors, reformate gas storages or other fuel cell systems) are under preparation.It is important to notice that the focus of the paper is on the explanation of the algorithms and not the calculation of the fuel consumption or emissions associated with one specific vehicle design or technology. Therefore all quoted data are only illustrative but are not intended to serve as evaluations of the potential of a certain technology.

The ability for crewmembers to explore the surface of the Moon or Mars effectively on foot remains a significant test of any exploration design. The availability of a pressurized rover would substantially increase the range of exploration by space suited crewmembers. The design of the airlock systems or functions will facilitate crewmembers in accomplishing these efforts. The pressurized rover for planetary exploration incorporates three types of airlocks or pressure ports: the EVA airlock, the sample airlock and the habitat docking port. This paper conducts a survey of selected precedents in pressurized rover design and then analyzes the key issues for airlock design. INTRODUCTION: THREE ENVIRONMENTS -THREE AIRLOCKS The airlock is the physical interface between the three working environments for crewmembers on the lunar or Mars surface. These environments are: the pressurized habitat in which the crew will live and work; the lunar/planetary surface and its atmosphere that require astronauts to wear space suits and carry their own life support; and the pressurized rover that gives them mobility over the surface. All three of these environments intersect in the pressurized rover. Thus, the pressurized rover for planetary exploration incorporates, at a minimum, three types of airlocks or pressure port functions: EVA egress and ingress, scientific sample ingress and removal, and docking or berthing to the pressurized habitat at the planetary base. Each of these three airlocks provides its own unique function that probably cannot be combined into a smaller number of devices. The EVA airlock enables spacesuited astronauts to egress and reenter the rover. The sample airlock provides the connection through which EVA crewmembers pass samples they have collected for analysis in the Astrobiology glove box, inside the rover. The habitat docking port is the connection through which the rover “docks” to the pressurized modules at the planetary base, and through which shirtsleeve crewmembers enter and exit the rover. REVIEW OF ROVER CONCEPTS & REQUIREMENTS In conducting this literature survey, the author began with the Apollo era studies such as the Lockheed MIMOSA study (1966-67) and the Boeing LESA study (1964-66). However, there was a remarkable 20 year hiatus between those studies in the mid-60s and the new flood of concepts that followed the landmark1984 conference on Lunar Bases and Space Activities of the 21st Century at the National Academy of Science in Washington DC (Mendell, 1985). This Conference set the philosophical agenda for human space exploration for at least the next 15 years, envisioning the return to the Moon and going on to Mars as one programmatic continuum. Beginning this review in the 1980s makes it possible to assume a common set of mission objectives and technologies, or at least an awareness of them on the part of the designers. The different approaches to these designs and technologies are significant for understanding why particular rover designs have certain attributes and lack others. Despite this sweep of time, the literature survey reveals surprisingly few serious studies of rover airlocks. Most airlock studies look at airlocks in general, in connection to Space Station or some other orbital vehicle. Thus, in selecting concepts from the literature for this review, it was a goal to find studies that address of airlocks, while including as many science-driven concepts as possible. From a design methodology perspective, this survey groups the pressurized rover concepts into three types of design approaches or sources: science-driven, mission architecture-driven, and system analysis-driven. TABLE 1 provides a comparative overview of the salient characteristics of each of the selected pressurized rover concepts that this paper discusses. These sets of requirements appear here much as they occur in the literature, with no effort to fill in

Two parallel HEV control concepts: ‘thermostat’ and ‘power split’ are compared in this paper. To achieve a substantial improvement in fuel economy, the ‘thermostat’ or ‘on/off’ control technique intended to improve the fuel efficiency of a series HEV has been adopted and designed for parallel HEV. Among different ‘power split’ concepts developed for parallel hybrids only the ‘electrically assist’ algorithm is considered in this paper. These two control concepts are compared for three parallel HEV architectures: pre-transmission, post-transmission and continuous variable transmission hybrids. The comparison study also includes the effect of hybridization factor—the ratio of the electric power to the total propulsion power. The matrices of comparison are level of performance, energy consumption and exhaust emissions. The SAE J1711 partial charge test procedure is followed. The full hybrid propulsion system is simulated using two EVHEV software packages: ‘V-ELPH’ developed by Texas A&M University and ‘ADVISOR’ from NREL. Based on the simulation results, the paper defines an optimum range of hybridization factor for the two control concepts.

Automotive manufacturers have relied on new technology for vehicular lighting systems, to illuminate the road or to highlight overall appearance. Lamps are more than just a bulb and a glass lens. This paper explains optical engineering, and how it advanced lighting engineering. Technological advances are highlighted, including past (halogens) and current technology (High Intensity Discharge (HID) lamps and Light Emitting Diodes (LEDs)). What often goes unnoticed with new technology is its effects on consumers, mainly in higher repair rates. The paper explains how some Original Equipment Manufacturers (OEMs) have improved upon or reduced lighting costs, yet maintained the lighting system's ability to add value. (A) For the covering abstract of the conference see ITRD E206480.

This paper describes an expert system for objective rating of subjective characteristics like driving comfort. The system uses radial basis neural networks that can be trained on any dynamic properties, for example acceleration. Training and retraining can be done in real time. The system includes a measure of the reliability of automatic judgement, which can be used to signal when new training may be necessary. The paper shows in detail how the system has been used to automatically judge gearshift comfort for automatic transmission. Tests indicate that the system's accuracy and consistency are as good as one of Volvo's best experts. (A) For the covering abstract of the conference see ITRD E206480.

The internal mixture formation within SI engines using fuel direct injection has a significant potential regarding the reduction of bsfc and pollutant emission. However the short time available for injection and spray distribution, as well as the complexity of the fluid dynamic conditions, amplified in a wide load and speed range, form a different base for the combustion process than using external mixture formation. The intend of the present study is to develop a method for modeling and optimization of mixture formation and combustion using a general approach for the fuel direct injection, which consist in the modulation of the injection rate, independently on the engine speed. In the first stage of modeling, the optimum combination between mixture formation elements as fuel pressure history, injection timing, spray characteristics, injector location or combustion chamber design is of great importance, forming the conditions for the subsequent combustion process. Moreover the interaction between fuel and air flow within the cylinder during the mixture formation is determining for the flame propagation. The model was developed in base of the commercial code FLUENT. Different combinations of fuel quantity, injection timing, fuel/air interaction and engine speed are represented as timeand spacerelated sequences of mixture formation. The program calibration is made by spray visualization for distinct cases, as a base of reliable simulation in a wide range of parameters. Complete paper available under: http://www.sae.org/servlets/productDetail?PROD_T YP=PAPER&PROD_CD=2000-01-0648

This paper presents an investigation of a Volvo Direct Injection Spark Ignition (DISI) engine, where the fuel distribution and the in-cylinder flow field have been mapped by the use of laser techniques in an engine with optical access. Along with the experimental work, CFD-modelling of flow and fuel distribution has been performed.Laser Induced Fluorescence (LIF) visualisation of the fuel distribution in a DI-engine has been performed using an endoscopic detection system. Due to the complex piston crown geometry it was not possible to monitor the critical area around the sparkplug with conventional, through the piston, detection. Therefore, an endoscope inserted in the spark plug hole was used. This approach gave an unrestricted view over the desired area.In addition, the in-cylinder flow fields have been monitored by Particle Image Velocimetry (PIV) through cylinder and piston.The results from both the LIF and the PIV measurements have been compared with CFD-modelling at Volvo. The validation was made at part load when the engine was operating in stratified mode, i.e. late injection during the compression phase. Qualitative agreement was found between the calculated and measured fuel distribution around the spark plug prior to ignition.Also the PIV measurements showed a promising agreement with the flow fields obtained by CFD-modelling. In addition, the transportation properties of the fuel distribution that was monitored by LIF could to a great extent be explained by the results from the PIV measurement and the CFD-modelling.All three techniques showed promising agreements with each other and the measured properties could be used to further increase the accuracy of the CFD-modelling. The close collaboration and comparison between different techniques described in this paper increased the understanding of the processes going on in the combustion chamber. (Less)

With today's trend of using multiplexed systems in mobile equipment comes the requirement for a Universal Display and Controller. These Universal Display Controllers (UDC) are used as a means of displaying information to the user issued to and received from the multiplexed systems. The UDC considered is a DOS-based unit allowing for ease of programming and customization for multiple OEM's. A PCMCIA interface is provided to download the functionality of the UDC, in addition to being used to retrieve logged data and configure nodes. Since the UDC's are located in a harsh environment, careful attention must be given to the wide ambient operating temperatures, sunlight readability, emissions, and other considerations unique to the environment. One of the most cirtical components of such a device is the display, which must survive these conditions and perform to the stringent requirements of today's equipment. The UDC discussed in this paper uses a Planar electroluminescent quarter-VGA display. This paper discusses the criteria for selecting a display component for these applications. (A) For the covering asbtract see IRRD E102826.

Passengers' frequent requests are for less Noise, Vibration and Harshness (NVH) in the vehicle compartment. This and the reduction of noise and vibration levels from major sources like the engine necessitate better performance of other sources of noise and vibrations in a vehicle. Some of these sources are the hydraulic circuits including the power steering system. Fluid pulses or pressure ripples, generated typically by a pump, become excitation forces to the structure of a vehicle or the steering gear and represent a considerable source of discomfort to the vehicle passengers. Current power steering technology attenuates this ripple along the pressure line connecting the pump to the steering gear. Finding the optimum design configuration for the components (hose, tuner, tube, and others) has been a matter of experiencebased trial and error. This paper is a part of a program to simulate and optimize fluid borne noise in hydraulic circuits. INTRODUCTION A fluid borne noise program is being developed. This program uses a database of experimentally characterized pumps, hoses and steering gears, where a test rig is built and used to develop such databases according to recent ISO standards [1]. These data are then used in simulation software to determine the optimal design configuration for a specific application. This optimization procedure determines, among other things, finding the hose, tube, and tuner lengths in a power steering configuration for a specific driving condition. The most frequent driving conditions in which the power steering noise is noticeable include: 1. Idle no load conditions. This is usually encountered while the driver is waiting in his vehicle (for example, in front of a traffic light). The driver usually leaves the engine running at 700 to 1000 rpm. Under this condition, no load is applied at the power steering system. The pressure in the fluid line can be up to 5 bar at the pump outlet to keep the system running and overcome energy losses. Drivers may experience this condition for extended periods in a traffic jam. 2. Parking conditions. These are encountered in the parking lot. The driver here is applying some load on the power steering system that will make the pressure reach up to 80 bar, while the engine is running at 800-1100 rpm. The duration of this condition is usually for several seconds (5 10 seconds). 3. Driving around corners in town. The driver usually runs the engine at speeds from 1500 to 2000 rpm, and puts the steering system under pressure values near 40 bar. The duration of this condition is approximated in seconds. 4. Steady state driving. This is a condition where the drivers experience when driving on the highway, where the engine is running between 1500 to 2500 rpm. The steering pressure is approximately 5 bar at the pump outlet and may reach 10 bar when changing lanes. 5. Accelerating while parking. This is experienced when the driver drives his vehicle in the parking lot fast. The driver, under this condition, will be driving his vehicle at 1500 rpm and putting up to 80 bar of pressure in the power steering system The last two conditions are usually investigated for loading and durability and rarely studied for noise. The reason is that engine noise levels under these conditions exceeds power steering noise levels. The first three conditions described above are considered the most critical. They produce objectionable noise levels. As can be seen, for these conditions the steering system experiences pressure values from 5 to 80 bar and engine speeds of 800 to 2500 rpm. With these values in mind, the system is usually investigated under the controlled conditions described in Reference 8. The engine usually drives power steering pumps at similar speeds. Typical pumps contain 10 pumping elements (vanes). This results in critical frequencies of the tenth order and their harmonics. Among other things, hoses, hoses with inserts or tuners, restrictors and other devices are used to attenuate the fluid ripple. The effect of hose parameters on the hydraulic system performance was studied earlier [6,7]. In this paper, certain important tuner parameters will be studied for their effects on the whole system NVH performance. This information should be valuable for design and research engineers involved in power steering systems. It should be mentioned that extensive correlation studies are being performed to correlate the theory established here with experiment. POWER STEERING SYSTEM MODEL The governing relations for input pressure and flow and output pressure and flow are needed for each component at any given frequency to assemble the system. We will first study the impedance of each of these components and then concatenate the system.

This paper focuses specifically on seat belt restraint system markings. Markings or observable anomalies on the webbing and restraint system hardware can be classified into two categories: (1) those caused by collision forces, or "loading marks"; and (2) those created by noncollision situations, or "normal usage marks". Some normal usage marks can appear visually similar to loading marks. The purpose of the paper is to help the investigator distinguish between occupant loading marks and normal usage marks by presenting examples of marks found on belt restraint systems that have never experienced occupant loading in a collision. A survey of the driver's belt system in 307 vehicles was conducted in the American state of Utah. Forty examples of a variety of normal usage marks are illustrated. The most commonly observed types of normal usage marks were: grooves, buffing, abrasions and grime buildup on the D-ring and latch plate; scratches on the latch plate tongue; fiber disruptions, staining, transfers or discolorations, cupping, folding and fraying on the webbing; latch plate tongue insertion marks, and contact marks on the buckle from the console, seat or occupant; and transfers or abrasions on other interior surfaces from interaction with restraint system components. For the covering abstract of the conference see IRRD E201455.

In previous SAE papers, the initial development and testing of a vacuum-insulated catalytic converter was presented. This paper provides an update of the converter development and an analysis of potential off-cycle emissions savings. Hot vibration, cool-down, and 1975 Federal Test Procedure (FTP-75) emissions test results are provided to demonstrate the effectiveness of design improvements in greatly increasing durability while retaining performance. Using standard drive cycles and "realworld" driving statistics with a vehicle simulator (ADVISOR), catalyst temperature and vehicle exhaust emissions of a sport utility vehicle (SUV) were predicted for 16 days of driving (107 trips, 770 total miles). Compared to the baseline vehicle with a conventional catalytic converter, the SUV with a vacuum-insulated converter produced 66% less non-methane hydrocarbon (NMHC), 65% less carbon monoxide (CO), and 60% less oxides of nitrogen (NOx).

Current performance specifications of seat belt pretensioners include web retraction and belt load. These criteria may adequately represent the performance requirements of a pretensioner in a restraint system. However, by themselves, they are inadequate to evaluate potential design modifications to improve efficiency levels and thus increase energy output of the pretensioner. This paper demonstrates a nonlinear phenomenon associated with web retraction and the belt load during pretensioning. It is this nonlinear behavior that promotes the insensitivity for use of web retraction in predicting the energy output of a pretensioner with design modifications. This paper proposes an energy measuring method that can be used to more accurately measure the energy output of a pretensioner and then be used to evaluate the effects on output of a pretensioner caused by design modifications.

The compression ratio is an important engine design parameter. It determines to a large extend engine properties like the achievable efficiency, the heat losses from the combustion chamber and the exhaust losses. The same properties are affected by insulation of the combustion chamber. It is therefore especially important to know the compression ratio when doing experiments with thermal barrier coatings (TBC). In case of porous TBCs, the standard methods to measure the compression ratio can give wrong results. When measuring the compression ratio by volume, using a liquid, it is uncertain if the liquid fills the total porous volume of the coating. And for a thermodynamic compression ratio estimation, a model for the heat losses is needed, which is not available when doing experiments with insulation. The subject of this paper is the evaluation of an alternative method to assess the compression ratio. It is based on motored cylinder pressure data like other thermodynamic methods but does not need a model for the heat losses. The validation and application of the method is done with data from experiments involving two types of porous TBCs, performed on a light duty single cylinder diesel engine. The results indicate that the proposed method accurately predicts the compression ratio for porous thermal barrier coatings.

A contemporary approach for improving and developing the understanding of heavy-duty Diesel engine combustion processes is to use a concerted effort between experiments at well-characterized boundary conditions and detailed, high-fidelity models. In this paper, combustion processes of n-dodecane fuel sprays under heavy-duty Diesel engine conditions are investigated using this approach. Reacting fuel sprays are studied in a constant-volume pre-burn vessel at an ambient temperature of 900 K with three reference cases having specific combinations of injection pressure, ambient density and ambient oxygen concentration (80, 150 & 160 MPa - 22.8 & 40 kg/m3-15 & 20.5% O2). In addition to a free jet, two different walls were placed inside the combustion vessel to study flame-wall interaction. Experimentally, low- and high-temperature reaction product distributions are imaged simultaneously using single-shot planar laser-induced fluorescence (PLIF) of formaldehyde and high-speed line-of-sight imaging of the chemically-excited hydroxyl radical (OH). Interference of soot incandescence in experimental OH∗ recordings is assessed to improve interpretation of the results. Interference by poly-cyclic aromatic hydrocarbon (PAH) LIF and soot radiation is mostly evaded by evaluating flame structures shortly after ignition for one of the studied cases, but presumably included in others. Simulations were performed using a recently developed computational fluid dynamics (CFD) methodology with detailed chemistry and turbulence-chemistry interaction. Apart from the capability to model flame structures and combustion indicators based on optical diagnostics, heat-release rate trends are predicted accurately at varying boundary conditions. Significant variation in the distribution of low-temperature combustion products under heavy-duty operating conditions are explained using both CFD simulations and a one-dimensional jet model.

Particulate emissions from Gasoline Direct Injection (GDI) engines have been an important topic of recent research interest due to their known environmental effects. This review paper will characterise the influence of different gasoline direct injection fuel systems on particle number (PN) emissions. The findings will be reviewed for engine and vehicle measurements with appropriate driving cycles (especially real driving cycles) to evaluate effects of the fuel injection systems on PN emissions. Recent technological developments alongside the trends of the influence of system pressure and nozzle design on injector tip wetting and deposits will be considered. Besides the engine and fuel system it is known that fuel composition will have an important effect on GDI engine PN emissions. The evaporation qualities of fuels have a substantial influence on mixture preparation, as does the composition of the fuel itself. Recently a number of studies have attempted to link fuel composition with PN emissions, developing a variety of indices including the PM index (Aikawa et al.) and the PN index (Leach et al.). An extensive literature search has been carried out and the PN index evaluated against these data. In addition the PM index and PN index are compared. The results of the review show that the Aikawa index should be applied when the fuel quality is known by lab reports, whereas the Leach index is relevant when only minimal information about a fuel is known, even the latter giving a relatively good prediction of PN emission trends from fuels in GDI engines.

Partially premixed combustion (PPC) is an advanced combustion strategy that has been proposed to provide higher efficiency and lower emissions than conventional compression ignition, as well as greater controllability than homogeneous charge compression ignition (HCCI). Stratification of the fuel-air mixture is the key to achieving these benefits. The injection strategy, injector-piston geometry design and fuel properties are factors commonly manipulated to adjust the stratification level. In the authors' previous research, the effects of injection strategy and fuel properties on the stratification formation process were investigated. The results revealed that, for a direct-injection compression ignition engine, by sweeping the injection timing from -180° aTDC (after top dead center) to -20° aTDC, the sweep could be divided into three different regimes: an HCCI regime, a Transition regime and a PPC regime, based on the changing of mixture stratification conditions. When running in the Transition regime, the engine's efficiency and emissions were poor. Hence, it is optimal to minimize the length of the Transition regime. At the same time, it would be very beneficial to expand the PPC regime as this allows greater tolerance between the stratification level and injection timing control, thus improving controllability. Accordingly, a method was proposed for lengthening the PPC regime and shortening the Transition regime by using a small spray angle injector or a wider bowl piston. In this paper, two piston designs with different bowl profiles were tested to observe the effect of piston bowl geometry on the stratification formation process. The results show that with a wider piston bowl, the early half of the PPC regime was lengthened by approximately 50% and the Transition regime was shortened. However, an unexpected "bump" in the required intake temperature was observed within the PPC regime with the wider bowl piston, which was assumed to be caused by a "hill" on the combustion chamber wall. Simulation work based on the experimental data was conducted using the KIVA-3v code. The results were used to analyze the fuel spray development processes and equivalence ratio distributions. (Less)

Lightly damped non-linear systems such as vehicular drivelines undergo a plethora of Noise, Vibration and Harshness (NVH) problems. The clonk phenomenon is one concern which occurs as the result of impulsive torque input in the form of sudden clutch actuation or throttle tip-in and back-out. The resulting impact of meshing gear pairs propagate structural waves down the driveline. With lightly damped thin-walled tubes having high modal density, elasto-acoustic coupling occurs. High frequency noise emission is of metallic nature and quite disconcerting to vehicle occupants as well as passers-by. It is perceived as structural failure and/or poor-quality build. Therefore, the occurrence of the phenomenon is a concern to vehicle manufacturers and progressively constitutes a warranty concern. This paper investigates the clonk phenomenon through use of a long-wheel base rear drive light truck test rig. The investigation uses psychoacoustic metrics to establish the severity of clonk noise in different maneuvers. This is an attempt to quantify the effect of transient clonk event which is usually ascertained through subjective evaluation ratings in a customer/jury clinic in industry. Alternatively, detailed numerical analysis is carried out with parametric studies to quantify different clonk events, a very time consuming approach which is not usually correlated with occupants’ perception of the event. Therefore, the experimental NVH monitoring-psycho-acoustic approach is new for the case of clonk and not hitherto reported in literature. The study corroborates the results and conclusions of previous work, pointing to the loudness and sharpness of high frequency short-lived “metallic” response, which is attuned to human aural perception. The psychoacoustic analysis has shown this to be as the result of short duration hard impact (accelerative period). This hard impact duration accounts for the bulk loudness and sharpness of the overall event. Therefore, effective palliation should focus on the attenuation of particular frequency bands, which carry the main contribution to loudness and sharpness.

With the increasing stringent emissions legislation on internal combustion engines, alongside requirements for enhanced fuel efficiency as key driving factors for many OEMs, there are many research activities supported by the automotive industry that focus on the development of hybrid and pure Electric Vehicles. This change in direction from engine downsizing to the use of electric motors presents many new challenges concerning NVH performance, durability and component life. This paper provides an experimental investigation into the measurement of NVH characteristics in these new powertrains, thus characterising the structure borne noise transmissibility through the shaft and the bearing to the housing. A feasibility study and design of a new system level test rig have been conducted to allow for sinusoidal radial loading of the shaft, which is synchronised with the shaft’s rotary frequency under high-speed transient conditions in order to evaluate the phenomena in the system. In the present work, simulations of the rig were conducted using the commercial multi-body dynamics software, AVL EXCITE Power Unit, providing insight to the systems response to different types of bearings such as deep groove ball bearings, tapered roller bearings and the cylindrical roller bearings. Moreover, influence factors such as bearing clearance and the amount of axial bearing preload are investigated. The test rig has multiple novel elements compared to those previously developed. In particular, the rotational speed of the shaft, which significantly exceeds that of previously reported rigs, and the excitation frequency ramp up at the same rate as the frequency of the shaft enabling the phenomena found in Hybrid and Electric Vehicles. The sinusoidal radial load is supplied using a loading device featuring a single load point to minimize undesired excitation effects. With respect to structure borne noise the system response is captured through the vibrational displacement of the shaft and bearing housing.

In this paper, computation fluid dynamics (CFD) simulations are employed to describe the effect of flow parameters on the formation of soot and NOx in a heavy duty engine under low load and high load. The complexity of diesel combustion, specially when soot, NOx and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution. In this work, Multiple Representative Interactive Flamelets (MRIF) method is employed to describe the chemical reactions, ignition, flame propagation and emissions in the engine. A phenomenological model for soot formation, including soot nucleation, coagulation and oxidation with O2 and OH is incorporated into the flamelet combustion model. Different strategies for modelling NOx are chosen to take into account the longer time scale for NOx formation. The numerical results are compared with experimental data to show the validity of the model for the cases under study. A good agreement is achieved between the model results and the pressure and heat release rate from the experiment. For soot and NOx, the model is able to correctly predict the trends between different cases. The effect of number of RIFs on the behaviour of the model is discussed.

The use of two-phase ejectors to recover expansion work to improve COP of transcritical R744 systems has been the subject of numerous investigations during the past decade. However, there is little understanding as to how oil in circulation in different parts of the system is affected when a two-phase ejector is used to replace the expansion valve. This paper presents detailed measurement results conducted on a transcritical R744 ejector system using polyalkylene glycol (PAG) oil, demonstrating that at the same test condition, the oil circulation rates (OCRs) in different parts of the system can easily vary by an order of magnitude. The highest OCRs of approximately 10% by mass were measured close to the evaporator inlet. The influence of compressor speed, ejector motive nozzle needle position and evaporator inlet metering valve opening on the OCRs was investigated and it is explained why these condition changes will result in variation of oil in circulation.

This CFD study focuses on the influence of the nozzle diameter on the mixing process and the soot formation and oxidation process in a heavy-duty diesel engine. The CFD simulation is based on the Reynolds Averaged Navier-Stokes approach. The engine set-up is similar to an experimental case that showed rather low soot emission. The aim of the paper is to improve the understanding of the physics of the mixing process in a real engine environment with the attention to scrutinize its effect of fuel injection on combustion and soot emission. Two non-reacting cases with different injector nozzle diameters but constant injection pressure and their corresponding reacting cases are simulated with dynamic mesh motion and fuel spray modeling. The influence of injections on the mixing, combustion and emissions is analyzed and the simulation results are compared with the measurement data. The differences in the mixing process between a constant volume vessel and a dynamic combustion chamber with piston motion are evidenced. The results show that a smaller nozzle diameter leads to a lower equivalence ratio and a higher gas temperature along the centre of the spray axis. The piston expansion causes the break-down of a recirculation zone around the spray which can affect the air entrainment. The CFD study captures the trend of the measurement data concerning the equivalence ratio around lift-off and the results explain the formation and oxidation process of soot. (Less)

Fuel supercriticality has recently received significant attention due to the elevated pressures and temperatures that directly-injected (DI) fuel sprays encounter in modern internal combustion (IC) engines. This paper presents a theoretical examination of conventional and alternative DI fuels at conditions relevant to the operation of compression ignition (CI) engines. The focus is to identify the conditions under which the injected liquid fuel can bypass the atomization process and directly transition to a diffusional mixing regime with the chamber gas. Evaluating the microscopic length-scales of the phase boundary associated with the injection of liquid nitrogen into its own vapor, it is found that the conventional threshold based on the interfacial Knudsen number (i.e. Kn = 0.1) does not adequately quantify the direct transition between sub- and supercriticality. Instead, a threshold that is an order of magnitude smaller is more appropriate for this purpose. Extending the analysis to a range of diesel fuel surrogates (e.g. n-heptane and n-dodecane), and alternative engine fuels that can be blended for use in CI engines (e.g. dimethyl ether and propane), it is then found that the local Knudsen numbers associated with the injection of conventional liquid fuels are significantly higher than those previously calculated in the literature, suggesting that those fuels will not directly transition to a dense-fluid mixing regime for all engine relevant conditions. However, the results show that the immediate transition to a single-phase regime may be relevant to lighter alternative fuels like DME and propane, which is attributed to the significantly lower critical temperature of these fuels, as well as their higher miscibility with the gas in the chamber.

Selective Non-Catalytic Reduction (SNCR), used to reduce the emissions of nitrogen oxides (NOx), has been a well-established technology in the power plant industry for several decades. The SNCR technique is an aftertreatment strategy based on thermal reduction of NOx at high temperatures. In the compression ignition engine application, the technology has not been applicable due to low exhaust temperatures, which makes the SCR (Selective Catalytic Reduction) system essential for efficient nitrogen oxide reduction to fulfill the environment legislation. For a general Double Compression Expansion Engine (DCEE) the complete expansion cycle is split in two separate cycles, i.e. the engine is a split cycle engine. In the first cylinder the combustion occurs and in the second stage the combustion gas is introduced and further expanded in a low-pressure expansion cylinder. The combustion cylinder is connected with the expansion cylinder through a large insulated high-pressure tank. If an ammonia based solution is injected after the combustion cylinder, the residence time and high gas temperature in the high-pressure tank allows the Selective Non-Catalytic Reduction mechanisms to ensue. In this paper, AUS 32 vaporization efficiency was studied by injection droplet distribution measurements and CFD simulations. The Selective Non-Catalytic Reduction concept was evaluated utilizing a 1D GT-SUITE model of a potential DCEE concept where the SNCR based mechanisms were added. Engine speed, normalized stoichiometric ratio (NSR), load and air-fuel excess ratio were swept in the 1D simulation process. The simulation results suggest efficient vaporization of AUS 32 and the presence of SNCR mechanisms in the Double Compression Expansion Engine's medium and high load operating points was verified with conversion efficiency above 50 % in some of the simulation cases for NSR = 1 and close to 80-100 % for NSR = 2 and NSR = 3 when the exhaust gas temperature from the combustion cylinder was in the optimal range for SNCR based reactions. (Less)

Thermodynamic power cycles have been shown to provide an excellent method for waste heat recovery (WHR) in internal combustion engines. By capturing and reusing heat that would otherwise be lost to the environment, the efficiency of engines can be increased. This study evaluates the maximum power output of different cycles used for WHR in a heavy duty Diesel engine with a focus on working fluid selection. Typically, only high temperature heat sources are evaluated for WHR in engines, whereas this study also considers the potential of WHR from the coolant. To recover the heat, four types of power cycles were evaluated: the organic Rankine cycle (ORC), transcritical Rankine cycle, trilateral flash cycle, and organic flash cycle. This paper allows for a direct comparison of these cycles by simulating all cycles using the same boundary conditions and working fluids. To identify the best performing cycle, a large number of working fluids were evaluated with regards to the maximum power output of the power cycle for each heat source. Taking into account the constraints and boundary conditions, this study shows that the ORC gives the best performance with a power output of around 1.5 kW for the coolant, 2.5 kW for the exhaust gas recirculation cooler, and 5 kW for the exhaust with acetone, cyclopentane and methanol as the best performing working fluids.