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Viewing 1 to 30 of 42298
2016-09-27
Technical Paper
2016-01-8067
Suresh Kumar Kandreegula, Kamal Rohilla, Gaurav Paliwal, Naveen Sukumar, Naveen Pratap Tripathi
Three on the tree. Four on the Floor. The gear change mechanism is a component that is too often taken for granted but it is one of the more important features of the vehicle. It must be quick and smooth in action, efficient and totally reliable. Modern driving conditions demand that the driver makes frequent gear changes and a mechanism that is temperamental or inaccurate can be both frustrating and dangerous as well as physically tiring. The gear changing mechanism starts, quite obviously, with the gear lever. Most stem from the fact that a gear lever must move in two planes, forward and back and then from side to side to move across the gear "gate". A good many drivers think of gear changing as one simple action. This is more a tribute to the design of gear changing mechanisms than a reality.
2016-09-27
Technical Paper
2016-01-8061
Thomas Howell, Bruce Swanbon, Justin Baltrucki, Alan Steines, Nancy Neff, Biao Lu
Heavy duty valvetrains continue have evolved over the last 20 years with the integration of engine braking into the valvetrain. Jacobs Vehicle Systems have developed the High Power Density engine brake that doubles the low speed retarding power and increases high speed retarding power. The system works by converting the engine from a 4 stroke during positive power into a 2 stroke for retarding. This provides substantial retarding power at cruise engine speeds reducing the need to downshift in order to control the vehicle, compensates for reduction in natural vehicle retarding due to aerodynamic and friction enhancements, and enables the same vehicle retarding power with a smaller displacement engine as engine downsizing becomes prevalent.
2016-09-27
Technical Paper
2016-01-8113
Xiaohua Zeng, Guanghan Li, Dafeng Song, Sheng Li, Xianghua Li
This paper introduces the configuration and operation principle of the hydraulic hub-motor auxiliary system for heavy truck, which could achieve auxiliary driving and auxiliary braking function. In order to achieve coordinate distribution of the engine power between mechanical and hydraulic system, the hydraulic pump displacement controller is designed. A layered auxiliary drive control strategy is proposed to improve vehicle performance. Finally, the simulation model is built in the MATLAB/Simulink and AMESim platform and the co-simulation is conducted to verify the proposed control strategy. The results show that the strategy could realize effective control and the traction force increased proportion can be up to 15.6~17%, which would significantly improve the drivability and passing capacity of heavy truck.
2016-09-27
Technical Paper
2016-01-8121
Riccardo Bianchi, Addison Alexander, Andrea Vacca
Vibrations at the cabin or at the implements of construction machinery represents important drawbacks from the points of view of machine productivity, safety and operator comfort. Oscillations of these machines are particularly relevant due to the absence of shock absorbers, typical of many machines such as wheel loaders, and their use in uneven ground conditions. Several hydraulic solutions have been proposed in the past to reduce oscillations at both the cabin or at the machine boom. Particularly, cabin oscillations can be attenuated by properly counteracting the exciting oscillatory forces from the tires with motion of the boom. Many state of the art machine utilize a passive methods to implement this strategy. The present work introduces a novel active solution, based on the control of the boom actuator without involving modifications of the standard hydraulic system.
2016-09-27
Technical Paper
2016-01-8062
Jham Kunwar Tikoliya, Ram Krishna Kumar Singh, Ramesh Kumar
The existing head cover is having external oil and blow by separation unit, which is not only costlier but also complex and leads to increase the overall height of engine which was difficult to integrate in new variants of vehicles. Existing head cover sealing system was also not foolproof and with slight variation in part dimensions, there were high chances of leakage. A new head cover has been designed with internal baffle type oil and blow by separation system to ensure efficient separation and proper packaging of the system in new varients.The new system has been finalized after 26 DOEs of different wire mesh sizes and different baffle plate size and positions. The final system has two bowl shaped separation unit with wire mesh with two cup type oil separation passages and one baffle plate for separating blow by. The system works on condensation and gravity method. The blow by is guided through a well-defined passage integrated in aluminum cylinder head cover itself.
2016-09-27
Technical Paper
2016-01-8063
David Ferreira, Thomas Howell, Peter Jo
Heavy duty valvetrains are not able to incorporate hydraulic lash adjusters due to the inclusion of an engine brake. As an engine brake introduces substantial lash into the valvetrain due to the addition of additional valve motions, the HLA would pump up. Jacobs Vehicle Systems has developed a new mechanism to allow the inclusion of an engine brake into a valvetrain equipped with hydraulic lash adjusters. The fulcrum system maintains a load on the hydraulic lash adjuster during engine brake operation preventing the HLA from pumping up. The addition of hydraulic lash adjusters allows for simpler manufacturing, less maintenance, reduced NVH and valve motion enhancements. This paper describes the design, simulation and testing of the lashless valvetrain including the next steps in the development of the valvetrain.
2016-09-27
Technical Paper
2016-01-8070
Prasad vegendla, Tanju Sofu, Rohit Saha, Mahesh Madurai Kumar, Long-Kung Hwang, Steven Dowding
Fan and Fan-shroud design is critical for underhood air flow management. The objective of this work is to demonstrate a method to optimize fan-shroud shape in order to maximize cooling air mass flow rates through the heat exchangers using the Adjoint Solver in STAR-CCM+®. Such techniques using Computational Fluid Dynamics (CFD) analysis enables the automotive/transport industry to reduce the number of costly experiments that they perform. This work presents the use of CFD as a simulation tool to investigate and assess the various factors that can affect the vehicle thermal performance. In heavy-duty trucks, the cooling package includes heat exchangers, fan-shroud, and fan. In this work, the STAR-CCM+® solver was selected and a java macro built to run the primal flow and the adjoint solutions sequentially in an automated fashion.
2016-09-20
Technical Paper
2016-01-1982
Michelle Bash, Steven Pekarek, Jon Zumberge
The cost and complexity of aircraft power systems often limits the ability to evaluate system performance using fully integrated aircraft hardware. As a result, evaluations are typically performed using emulators to mimic components or subsystems. As an example, aircraft generation systems are often tested using an emulator that consists of a bank of resistors that are switched to represent the power draw of one or more actuators. The limitation of this approach is that the switched resistive load falls short of representing the dynamic load characteristics of aircraft actuators or other power electronic loads, and thus the true integrated performance cannot be evaluated. In this research, consideration is given to modern emulators that use power electronics and digital controls to obtain wide bandwidth control of power, current, or voltage.
2016-09-20
Technical Paper
2016-01-1991
Syed J. Khalid
Engine bleed and power extraction are required by the aircraft to operate the various onboard subsystems which are necessary for the proper functioning of the aircraft. These extractions are parasitic for engine performance and operation. The engine companies make large investments in technology to achieve a couple of percent in engine efficiency. These gains can be quickly negated if bleed and power extraction are not judiciously managed for minimizing the amounts of extractions. Permission has been obtained from Boeing to use their public domain information on subsystem architecture to articulate the message in this paper. Help from Boeing and from Specific Range Solutions Ltd of Canada in the preparation of this paper is acknowledged. The paper will first quantify the detrimental effects of bleed and power extraction on engine performance and operation using the proven GasTurb 12 performance software. The engine modelled is similar to a modern transport aircraft turbofan.
2016-09-20
Technical Paper
2016-01-1981
Luis C. Herrera, Bang-Hung Tsao
One of the main challenges in the power systems of future aircraft is the capability to support pulsed power loads. The high rise and fall times of these loads along with their high power and negative impedance effects will have an undesirable impact on the stability and dc bus voltage quality of the power system. For this reason, studying ways to mitigate these adverse effects are needed for the possible adoption of these type of loads. One of the technologies which can provide benefits to the stability and bus power quality is Energy Storage (ES). This ES is designed with the capability to supply high power at a fast rate. In this paper, the management of the ES to mitigate the effects of pulsed power loads in an aircraft power system is presented. First, the detailed nonlinear model of the power network with pulsed power loads is derived. Due to the large size of this model, a model order reduction is performed using a balanced truncation.
2016-09-20
Technical Paper
2016-01-1998
Michele Trancossi, Jose Pascoa, Carlos Xisto
Environmental and economic issues related to the aeronautic transport, with particular reference to the high speed one are opening new perspectives to pulsejets and derived pulse detonation engines. Their importance relates to a very high thrust to weight ratio and very low cost of manufacturing. This papers presents a multi-chamber cooled pulsejet architecture, which has been specifically designed for reducing the vibrations induced by a single chmber and tube pulsejet architecture. After preliminary design considerations it will take into account the thermal problem of this very simple and unespansive propulsion system. It analyses the heat transfer process through the wall of the combustion chamber of a pulsejet for aeronautic propulsion. The inside wall is exposed to burning gases with an average temperature of 1200 K, which oscillates with an amplitude 500 k and a frequency of 50 hz.
2016-09-20
Technical Paper
2016-01-2020
Constanza Ahumada Sanhueza, Andrea Bristot, Shubham Kumar, Nicolas Schneider, Seamus Garvey, Herve Morvan
This paper proposes an integrated system’s approach towards design of some aero-engine subsystems - seals, bearing chamber, generator and power system. In a conventional design approach, the design of the overall system is typically broken-down into subsystems. Therefore, the focus is not on the mutual interaction between different components or subsystems, resulting in a lack of characterisation of the overall system performance at the design phase. A systems design approach adopts a much broader outlook, focusing on the overall optimization of the system performance. One of the principal contributors in the performance of an aircraft is the aero-engine. In particular, for a More Electric Aircraft, any abrupt changes to the electrical load from the power system can have an effect on the shaft dynamics, which in turn can affect the performance of air seals.
2016-09-20
Technical Paper
2016-01-2017
Devesh Kumar, Konrad Juethner, Yves Fournier
The aero engine industry is experiencing both a design renaissance and an adherence to old values in recent years. Engine manufacturers have introduced remarkable next generation capabilities by achieving thermodynamic and mechanical efficiencies and exploring novel lightweighting concepts such as the open rotor configuration [1]. At the same time, the market adheres to 50+ year-old engine concepts that have proven extremely reliable and demands continuous adaption to new applications. In either domain, it is a common problem to keep engine simulation in step with changes to design, environmental conditions, and mission data – and this applied to both actual designs and those that belong to the hypothetical design space as explored in design of experiments (DOE). We present an effective simulation process and data management (SPDM) approach that hinges on a focus on components, their generalized connections and programmatic templating.
2016-09-20
Technical Paper
2016-01-1994
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
For aircraft electromechanical actuator (EMA) cooling application, the main objectives in axial fan design are high pressure head and high efficiency over a wide operating range including speed variation 1x~3x and pressure 0.2~1atm variation. The fan is based on a thickness of 2.54 cm, 48 mm hub, 86 mm fan diameter. The purpose of this study is to characterize a fan's performance at various rotational speeds and various ambient pressures, from 0.2 atm to 1 atm. Methodology An 86-mm diameter axial fan for electromechanical actuators was designed. The blade shape was obtained by optimization design of the radial blade using CFD technique. Geometrical parameters describing the variations of the blade profile were determined by hub contour and fan’s required parameters given above. The 3,5, 7-blade configurations were compared with the optimal blade profile. A commercial brushless DC axial fan motor is chosen. The fan blades were 3-D printed and tested in a closed test loop.
2016-09-20
Technical Paper
2016-01-1997
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
Recently there has been increasingly research interest on aircraft electromechanical actuator (EMA) safety. One approach to prevent EMAs from overheating is to use air cooling fans. Aircraft EMA cooling fan is a critical component because an EMA failure due to overheating could lead to a catastrophic failure in aircraft. Methodology A five-blade and seven-blade dual-fan designs are proposed. Each fan has its own independent shaft running in opposite rotating directions. Fan motors are assumed to be brushless direct current (BLDC) motors. After summarizing the possible failure causes and failure modes of BLDC fans by focusing on each failure mechanism, the life expectancy of fan ball bearings based on a major failure mechanism of lubricant deterioration was calculated and compared to such information in the literature. Finally, the advantages and disadvantages of three fault-tolerant approaches are discussed.
2016-09-20
Technical Paper
2016-01-2067
Qingchuan Shi, Kartik Lakshminarashimhan, Christopher Noll, Eelco Scholte, Omer Khan
Modern aircraft systems employ numerous processors to achieve system functionality. In particular engine controls and power distribution subsystems rely heavily on software to provide safety-critical functionality and are expected to move towards multicore architectures. The computing hardware-layer of avionic systems must be able to execute many concurrent workloads under tight deterministic execution guarantees to meet the safety standards. Single-chip multicores are attractive for safety-critical embedded systems due to their lightweight form factor. However, multicores aggressively share hardware resources, leading to interference that in turn creates non-deterministic execution for multiple concurrent workloads. We propose an approach to remove on-chip interference via a set of methods to spatio-temporally partition shared multicore resources.
2016-09-18
Technical Paper
2016-01-1941
Tie Wang, Xin Gao, Zhiwei Zhang
Vehicle hydraulic retarder is applied in heavy-duty trucks and buses as an auxiliary braking device. In traditional cooling system of hydraulic retarder, working fluid is introduced into heat exchanger to transfer heat to cooling liquid in circulation, whose heat is then dissipated by engine cooling system, not enabling waste heat of working fluid used effectively. In hydraulic retarder cooling system based on Rankine cycle, organic working fluid transfers heat with hydraulic retarder working fluid in Rankine cycle, and then outputs power through expansion machine. It can both reduce heat load of engine cooling system, and enhance thermal stability of hydraulic retarder while recovering and utilizing braking energy. First of all, according to the target vehicle model, hydraulic retarder cooling system model based on Rankine cycle is established.
2016-09-18
Technical Paper
2016-01-1927
Christian Riese, Frank Gauterin
New technologies like alternative power trains and driver assistance systems have a big impact on brake system development. Most of the development work aims at the improvement of actuation and modulation of the brake system. The basic hydraulic network remained nearly the same over decades and still has to meet these new requirements. Previous papers have focused mainly on studying the behaviour of single components, like for example the brake hose fluid consumption in detail. Other papers studied the complete system but simplified it extremely, so that some relevant effects are neglected. In this work, one focus is to study the influence of single relevant components, like the hydraulic unit and the hoses on the overall system performance. For this measurements with a complete hydraulic brake system, including a state of the art electromechanical brake booster and single component measurements for identification are conducted.
2016-09-18
Technical Paper
2016-01-1938
Xin Gao, Tie Wang, Mengzuo Han
Hydraulic retarder is an auxiliary brake used by commercial vehicle in long slope brake. Working liquid generates a lot of heat during hydraulic retarder working. If the heat is not properly managed, it will seriously affect hydraulic retarder braking performance. Refrigerant outlet temperature of condenser in Rankine cycle is lower, condensing more fully. But the two-phase area of evaporator reduces or even disappears. Anyhow, Rankine cycle evaporate-condensate system parameter setting not reasonable will affect efficiency of whole system and the temperature stability of hydraulic retarder. The article uses Rankine cycle which refrigerant is R141b to replace hydraulic retarder original cooling system. It can make hydraulic retarder heat exchange in time and working fluid temperature stability in a smaller range.
2016-09-14
Technical Paper
2016-01-1871
Renxie Zhang
Path following controller of a six-wheel skid-steering vehicle is designed. The vehicle speed is controlled through engine speed control and the lateral vehicle steering is controlled through hydraulic braking on each side. Contrary to the common approaches considering non-holonomic constraints, vehicle dynamic characteristics and rotating wheels are considered. A hierarchical control structure is applied in this vehicle control system. The kinematic controller works out the reference yaw rate and reference vehicle speed. And a robust dynamic controller tracks the reference signal. In addition, the dynamic controller takes actuator ability into account.
2016-09-14
Technical Paper
2016-01-1886
Zhuoping Yu, Yi Zhang, Lu Xiong, Songyun Xu
With development of vehicle advanced driver assistant system and intelligent techniques, safer and more intelligent Integrated-Electro-Hydraulic Braking System is required to realize brake-by-wire. Thus, more and more companies and universities developed Integrated-Electro-Hydraulic Braking System to fulfill these requirements. In this paper, an Integrated-Electro-Hydraulic Braking System is introduced, which consists of active source power, pedal feel emulator, electro control unit and hydraulic control unit. As a composite system of mechanic, electron and hydraulic pressure, the Integrated-Electro-Hydraulic Braking System has complex system characteristics. Based on system characteristics experiments through test rig, characteristics of Integrated-Electro-Hydraulic Braking System and active power source are compared, the two systems have very different dynamic characteristics.
2016-06-17
Journal Article
2016-01-9141
Vinod Saini, Sanchit Singh, Shivaram NV, Himanshu Jain
Abstract In this paper, an optimization method is proposed to improve the efficiency of a transmission equipped electric vehicle (EV) by optimizing gear shift strategy. The idea behind using a transmission for EV is to downsize the motor size and decrease overall energy consumption. The efficiency of an electric motor varies with its operating region (speed/torque) and this plays a crucial role in deciding overall energy consumption of EVs. A lot of work has been done to optimize gear shift strategy of internal combustion engines (ICE) based automatic transmission (AT), and automatic-manual transmissions (AMT), but for EVs this is still a new area. In case of EVs, we have an advantage of regeneration which makes it different from the ICE based vehicles. In order to maximize the efficiency, a heuristic search based algorithm - Genetic Algorithm (GA) is used.
2016-06-15
Technical Paper
2016-01-1805
Florian Zenger, Clemens Junger, Manfred Kaltenbacher, Stefan Becker
Abstract A low pressure axial fan for benchmarking numerical methods in the field of aerodynamics and aeroacoustics is presented. The generic fan for this benchmark is a typical fan to be used in commercial applications. The design procedure was according to the blade element theory for low solidity fans. A wide range of experimental data is available, including aerodynamic performance of the fan (fan characteristic curve), fluid mechanical quantities on the pressure and suction side from laser Doppler anemometer (LDA) measurements, wall pressure fluctuations in the gap region and sound characteristics on the suction side from sound power and microphone array measurements. The experimental setups are described in detail, as to ease reproducibility of measurement positions. This offers the opportunity of validating aerodynamic and aeroacoustic quantities, obtained from different numerical tools and procedures.
2016-06-15
Technical Paper
2016-01-1802
Mehdi Mehrgou, Franz Zieher, Christoph Priestner
Abstract Recently, hybrid and fully electric drives have been developing widely in variety, power and range. The new reliable simulation approaches are needed, in order to meet the defined NVH targets of these systems and implementing CAE methods for front loading, Design Validation Process (DVP). This paper introduces the application of a novel NVH analysis workflow on an electric vehicle driveline including both electromagnetic and mechanical excitations for an absolute evaluation of the NVH performance. At first, the electromagnetic field is simulated using FEM method to extract the excitations on the stator, rotor bearings as well as the drive torque. Then, the multibody dynamic model of the driveline is built-up, driven by this torque. The effect of eccentricity and skew angle of rotor in electromagnetic excitations are shown.
2016-06-15
Technical Paper
2016-01-1798
Quentin Buisson, Jean-Louis Guyader, Serge Puvilland, Xavier Carniel, Maximilien Soenen
Abstract The goal of the present study is to provide a simple method to compare structure borne noise sources in order to choose the most efficient one, considering the transmission of dynamic forces. It is well known that mechanical sources are not only dependent of the source itself but also of the receiving structure, in addition real sources cannot be reduced to a transverse force acting on the structure but more complicated effect like moment excitation must be taken into account. The advantage of the reception plate method is to characterize the source globally by the level of vibration of the reception plate whatever the type of excitation, the idea is basically to characterize mechanical sources as it is done for acoustical sources in reverberant rooms. A reception plate test bench has been developed to determine the power injected by mechanical sources. Two prototype plates have been designed in order to have different receiving mobilities.
2016-06-15
Technical Paper
2016-01-1792
Aurélien Lonni, Olivier Tanneau
Abstract Nowadays, downsizing and turbochargers are more frequently used, mostly for petrol engines. It can lead to an increase of NVH issues related to the turbos, such as the hiss noise propagation in the air ducts. Hutchinson, among all its activities, supplies rubber and plastic parts for the car industry, especially in fluid management systems. The turbocharger’s airborne noise issue has now been tackled for ten years by implementing acoustic devices in the line and providing solutions to car manufacturers with our hot-side rubber ducts. In this paper, will be first presented the main HP air loop NVH issues, and then explained an approach to design technical solutions. Generally speaking, the noise propagates inside the hot side air hoses, crosses the weakest parts of the system by acoustic emissivity to reach finally the driver and passengers’ ears.
2016-06-15
Technical Paper
2016-01-1822
Drasko Masovic, Franz Zotter, Eugene Nijman, Jan Rejlek, Robert Höldrich
Abstract Radiation of sound from an open pipe with a hot mean flow presents one of the classic problems of acoustics in inhomogeneous media. The problem has been especially brought into focus in the last several decades, in the context of noise control of vehicle exhaust systems and jet engines. However, the reports on the measurements of the radiated sound field are still rare and scattered over different values of subsonic and supersonic flow speeds, cold and hot jets, as well as different sound frequency ranges. This paper focuses on low Mach number values of the mean flow speed and low frequencies of the incident (plane) sound waves inside an unflanged cylindrical pipe with a straight cut. It presents the results of the far-field radiation pattern measurements and compares them with an existing analytical model from the literature. The mean flow inside the pipe reached Mach number values up to 0.25 and temperature up to 300°C.
2016-06-15
Technical Paper
2016-01-1820
Mikael Karlsson, Magnus Knutsson, Mats Abom
Abstract This work explores how fluid driven whistles in complex automotive intake and exhaust systems can be predicted using computationally affordable tools. Whistles associated with unsteady shear layers (created over for example side branches or perforates in resonators) are studied using vortex sound theory; vorticity in the shear layer interacts with the acoustic field while being convected across the orifice. If the travel time of a hydrodynamic disturbance over the orifice reasonably matches a multiple of the acoustic period of an acoustic feedback system, energy is transferred from the flow field to the acoustic field resulting in a whistle. The actual amplitude of the whistle is set by non-linear saturation phenomena and cannot be predicted here, but the frequency and relative strength can be found. For this not only the mean flow and acoustic fields needs to be characterized separately, but also the interaction of the two.
2016-06-15
Technical Paper
2016-01-1818
Raimo Kabral, Lin Du, Mats Abom, Magnus Knutsson
Abstract The concept of IC engine downsizing is a well-adapted industry standard, enabling better fuel conversion efficiency and the reduction of tailpipe emissions. This is achieved by utilizing different type of superchargers. As a consequence, the additional charger noise emission, at the IC engine inlet, can become a problem. In order to address such problem, the authors of this work have recently proposed a novel dissipative silencer for effective and robust noise control of the compressor. Essentially, it realizes an optimal flow channel impedance, referred to as the Cremer impedance. This is achieved by means of a straight flow channel with a locally reacting wall consisting of air cavities covered by an acoustic resistance, e.g., a micro-perforated panel (MPP). In this paper, an improved optimization method of this silencer is presented. The classical Cremer impedance model is modified to account for mean flow dependence of the optimal wave number.
2016-06-15
Technical Paper
2016-01-1814
Maxime Legros, Jean Michel Ville, Solène Moreau, Xavier Carniel, Christophe Lambourg, Guillaume Stempfel
Abstract The new requirements during the first stages of the conception of a HVAC prompt the designer to integrate the acoustic problematic increasingly upstream. The designer needs to select a coherent components’ choice in order to comply with the specifications in terms of aeraulic and acoustic performances. A tool has been created to guide the designer’s choices based on an acoustic synthesis which is a design and/or diagnosis approach used to analyze and predict the acoustic behavior of a complex system. The synthesis is developed in order to propose an approach which considers the integration effects and some interaction effects. The acoustic synthesis results are the starting point of a psycho-acoustic study providing audio samples of the prediction and indications of the HVAC acceptance by the prospective user. Also, one may compare the results of different acoustic synthesis projects to study the influence of the parameters on the acoustic prediction.
Viewing 1 to 30 of 42298