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Technical Paper
2014-11-11
Manikandan T, S Sarmadh Ameer, A Sivakumar, Davinder Kumar, R Venkatesan, VenkataKalyana kumar
The proposed paper is on advanced vehicle information panel which shall display instant mileage zone in which the user is operating with inputs from engine crank sensor and vehicle speed sensor alone. And moreover, gear assistance and throttle assistance through visuals is provided. Mileage data for different engine loading at different Speeds is pre-calculated at standard conditions and fed into a micro-controller. In real time, the engine loading, by means of intelligent software, is sensed by engine crank sensor and based on the pre-fed value, the mileage zone of the vehicle at that particular instant is to be displayed using an information panel. Based on the relation between speed sensor and engine crank sensor when the vehicle is running, the gear in which the vehicle is running is to be calculated. For a vehicle running in a certain gear and in certain speed, the ideal engine loading and mileage zone is predefined. So when the user is riding in a certain gear with certain engine load, the micro controller compares that with the programmed data which is the ideal condition data, and assists the user, in case the rider is not riding the vehicle as per the ideal data, by gear up/down prompt or throttle up/down prompt by means of the said information panel.
Technical Paper
2014-11-11
Manikandan T, S Sarmadh Ameer, A Sivakumar, Samaraj Dhinagar
The proposed paper is on electrical energy conservation in a two wheeler. Electrical energy generation adds a maximum of 10% excess load torque on an engine and hence saving electrical energy would ultimately reduce the consumption of fuel. Load Control Module is a single intelligent device which is placed in between electrical energy generation and consumption. The Module controls and distributes energy to the corresponding loads depending on parameters like battery voltage, engine RPM, overhead light illumination levels and load usage time. The Module prioritizes battery charging for maintaining the life of the battery. The Module has a microcontroller and it is programmed with algorithm for prioritization and energy distribution with respect to input conditions. A vehicle fitted with the Load Control Module was tested in city driving cycle (CDC) condition as per ARAI (Automotive Research Association of India) standard and it was found that the electrical loading decreased to about 30% when compared to vehicle with uncontrolled loading.
Technical Paper
2014-11-11
Alessandro Franceschini, Emanuele Pellegrini, Raffaele Squarcini
Nowadays the challenge in design auxiliary device for automotive small engine is focused on the packaging reduction and on the increase of the performances. This requirements are in contrast to each other and in order to fulfil the project specifications, new and more refined design tools and procedures need to be developed. This paper presents a calculation loop developed by Pierburg Pump Technology Italy S.p.a. (PPT). It supports the design of a variable displacement oil pump component for engine applications. The work is focused on the fatigue life evaluation of a joint, which transmits the drive torque from the engine to the oil pump. The aim of the procedure is to calculate the onset of the surface fatigue phenomenon in the hexagonal joint which drives the oil pump, taking into account the axes misalignment and the flat to flat clearance. The study has involved several matters, experimental measures, CFD, MBA and FEM analyses. A calculation procedure has been set up in order to consider all the necessary loads applied on the joint.
Technical Paper
2014-11-11
Daniele Barbani, Niccolò Baldanzini, Marco Pierini
Motorcycle accidents are a serious road safety issue in the European Union (EU). Several projects to increase motorcycle safety were funded by the EU within the FP7 (Seventh Frame Program). Many others are likely to be funded within H2020 (Horizon 2020) as well as by national projects of each member state. In this context, numerical simulations play a strategic role since they can be a powerful tool to simplify, assist and speed up the work of the engineers. During the last years, the authors have presented the development and validation of FE models for complete crash test scenarios (i.e. motorcycle with an anthropometric test dummy that impacts against a car) and their use to evaluate head and neck injuries. During the validation phase the authors observed some variability in the results. While variability of the input parameters is a fact in real world crash test, the extent of the variability in the results has to be estimated and assessed in order to improve the design process of safety devices.
Technical Paper
2014-11-11
Federico Giovannini, Niccolò Baldanzini, Marco Pierini
The Powered Two-Wheelers (PTWs) control is more complex than any other road vehicle control, due to the implicit instability of those vehicles. Maneuvers such as braking or swerving, require additional driving abilities to prevent the vehicle from falling, in particular during emergency events, such as panic braking or last second swerving. Focusing on emergency braking maneuvers, in those situations the PTW control is very demanding due to the necessity to adjust the braking intensity in the best way. For standard PTWs, a common cause of accident is the loss of adherence and the consequent loss of stability due to emergency braking manoeuvers. It is worth noting that, for a PTW, the loss of stability means a high probability of fall, especially while cornering. Accordingly, the aim of this study is to propose and evaluate a fall detection algorithm for PTWs performing braking manoeuvers, developed to alert an advanced riding assistance system in order to produce proper counteractions against the imminent fall.
Technical Paper
2014-11-11
Patrick Falk, Christian Hubmann
KEYWORDS – Driveability, Motorcycle, Measurement, Powertrain, Quality ABSTRACT - Originally developed for the automotive market, a fully automatic real-time measurement tool AVL-DRIVE is commercially available for analyzing and scoring vehicle drive quality, also know as “Driveability”. This system from AVL uses its own transducers, calibrated to the sensitivity and response of the human body to measure the forces felt by the driver, such as acceleration, shock, surging, vibration, noise, etc. Simultaneously, the vehicle operating conditions are measured, (throttle grip angle, engine speed, gear, vehicle speed, temperature, etc). Because the software is pre-programmed with the scores from a multitude of different vehicles in each vehicle class via neural networks and fuzzy logic formula, a quality score with reference to similar competitor vehicles is instantly given. This tool is already successfully implemented in the market for years to investigate such driveability parameters for passenger cars.
Technical Paper
2014-11-11
Gokul Meenakshi Sundaram, Shankapal S R PhD, Nagarjun Reddy M.
A well rated vehicle should have good handling (maneuvering) and stability characteristics. In India, three wheeled vehicle (Auto –rickshaws) play a major role in low cost transportation and thus there is a huge population of them, particularly in urban areas. Auto -rickshaws are low speed vehicles and can easily be maneuvered in city narrow lanes. Hence these vehicles should exhibit stability as well as handling well at low speeds. Stability of vehicle is affected while maneuvering, and maneuvering (handling) gets affected due to wobbling of front wheel. The present work focuses on improving wobbling of a three wheeled vehicle. The problem was approached by carrying out a literature review and identifying the wobbling control equation. Parametric studies were done through simulation to understand their effect on wobbling. The wobbling frequency of front structure of three wheeled vehicle found to be 4 Hz corresponding to a vehicle speed of 20km/h. It was essential to reduce the wobbling frequency corresponding to a speed lower than 10 km/h.
Technical Paper
2014-11-11
R Varunprabhu, Himadri Bushan Das, S Jabez Dhinagar
The steering system of a 3-wheeler vehicle comprises a single column steering tube. The steering inclination at handle bar end is converted to wheel slip or inclination by the steering column. A compromise in either ride or handling is considered in the functional requirement of the 3-wheeler vehicle. The three wheeled vehicle under study is designed for ride comfort and the handling levels are compromised. Variants of the vehicle under study are meant for public passenger transport requirements. Drivers’ ride comfort is considered as the primary functional requirement during design and driver’s steering fatigue is not given importance. For the comfort of driver, steering effort has to be less without compromise in handling characteristics. The driver of this type of vehicle drives the vehicle for 15-18 hours a day. Driver’s feedback suggests high steering effort as a human fatigue failure mode and also a cause of shoulder pain. In this project, a DC motor assisted steering mechanism with an electronic control module has been designed.
Technical Paper
2014-11-11
Sei Takahashi, Hideo Nakamura, Makoto Hasegawa
The International Standard ISO26262 “Road vehicles - Functional safety” was published in 2011. Safety is one of the key issues of future automobile development. System safety is achieved through a number of safety measures, which are implemented in a variety of technologies. ISO26262 provides an automotive-specific risk-based approach and uses ASILs to specify applicable requirements so as to avoid unreasonable residual risk. The International Standard ISO26262 divides the Automotive Safety Integrity Levels (ASIL) into four stages (from level A to D). In this paper we consider the suitable determination of the Motorcycle Safety Integrity Levels (MSIL) when the ISO26262 is applied to motorcycles. We will show that an unreasonable risk area for motorcycles becomes smaller when compared with that of an automobile for the following two reasons. (1) The seating capacity of a motorcycle is less than that of an automobile, and thus the damage from a motorcycle accident is also smaller than those of automobile accidents.
Technical Paper
2014-11-11
Maki Kawakoshi, Takashi Kobayashi, Makoto Hasegawa
Controllability (C) is the parameter that determines the Automotive Safety Integrity Level (ASIL) of each hazardous event based on an international standard of electrical and/or electronic systems within road vehicles (ISO 26262). On application to motorcycles of ISO26262 that was intended only for passenger cars, it is considered that it is desirable to estimate the C class by subjective evaluation of expert riders. Expert riders are professional test riders, and they differ from ordinary riders. They can ride safely and evaluate the motorcycle performance stably even if the test condition is at the limit of vehicle performance. Expert riders evaluate motorcycle performance from the viewpoint of ordinary riders. However, riding maneuvers of ordinary riders have not been confirmed by objective data. For this reason, it is important to understand the basic characteristics of riding maneuvers of expert riders and of ordinary riders. This study seeks to confirm the compatibility between the riding maneuvers of expert riders and those of ordinary riders.
Technical Paper
2014-11-11
Kenichi Morimoto, Kenichi Tanaka
This study describes methods to explain the relationship between the motorcycle specifications and the shimmy phenomenon. Statistical approaches were used presuming the analysis being based on the multibody dynamics simulation having a high degree of freedom to precisely simulate actual motorcycle. There are a number of past attempts to clarify the relationship between the motorcycle specifications and the shimmy phenomenon. One of such efforts is based on the equation of motion. Although such a method is suitable when simply analyzing motions in a fundamental structure, when the number of degrees of freedom is large, generally a practical method cannot be found because it is extremely difficult to deriver an equation of motion. In the meantime, although the author et al. have analyzed shimmy using such multibody dynamics simulation models, the findings are useful only for simulation of performance difference among a number of motorcycles. In this study, we conducted researches taking three steps; (1) extract factors significantly affecting shimmy from motorcycle specifications, (2) explain how a change of motorcycle specifications affects shimmy, and (3) measure performance of a number of motorcycles having various specification.
Technical Paper
2014-11-11
Kazuhiro Ito, Yoshitaka Tezuka, Atsushi Hoshino, Keita Sakurada
The frame body of a motorcycle is a core part that receives force from the road via the front and rear suspensions as well as holding heavy objects such as the engine. It is therefore important to finish fundamental design in the early stage of product development. Regarding the strength of frame body, if the load input to the frame body under the hardest condition like on rough roads can be estimated by simulation, an appropriate frame body design in the early stage of development would be possible. Some techniques have been recently introduced to estimate input loads and/or fatigue strength by the full vehicle simulation to analyze the automobile running on rough roads. In motorcycles, meanwhile, there are some cases with making on the test bench of strength and/or durability tests, and conversion of such tests to CAE simulation. However, there are only a few cases with estimating input loads when running on rough roads. One of the reasons is that it is difficult to accurately estimate suspension motions, especially the motions of telescopic front suspension taking into account the motion in the bending direction.
Technical Paper
2014-10-13
Hyunsup Yang, Kyung Seok Cho, Chi Yong Park, Dae Bok Keon, Chang Ha Lee, Yong Sun Park
Fuel Cell Electric Vehicles (FCEV) is zero emission vehicles because it produces only water as a byproduct. The other advantages are a long driving range and a quick refueling time compared with the pure electric vehicle. The air compressor supply compressed air to the cathode of fuel cell stack to chemically react with the hydrogen from the compressed hydrogen tank to generate electric power. The majority of the companies have used displacement type screw compressor for their current and next generation air supply systems. The screw type air compressor was used for the supercharged internal combustion engines. Screw type air compressor has some advantage in increasing pressure ratio but it has disadvantage in NVH (Noise, Vibration and harshness), efficiency and productivity. Among them NVH is the greatest factor that inhibits the marketability of FCEV because it has no noise source such as internal combustion engine. Because of that, the screw type air compressor should have very expensive noise cover and muffler for the reducing of the pressure fluctuation to improve NVH level.
Technical Paper
2014-10-13
Gerhard Kokalj, Patrick Schatz, Christoph Zach
The automotive industry is racing to introduce some degree of hybridization into their product ranges. Since the term “hybrid vehicle” can cover a wide range of differing technologies and drivetrain topologies, this has led to a plethora of vehicles that call themselves “hybrid”. This poses an interesting challenge for marketers to differentiate these vehicles from the incumbents. However, it is not just the marketers who are faced with challenges, the developers of such hybrid drivetrains are faced with a rise in technical complexity due to the wide range of operating modes hybridization introduces. As propulsive torque is being generated in more than one place in a hybrid vehicle, the transitions from conventional drive to electrically supported drive bring with them complex aspects of multi-dimensional system control. The challenge is to be able to implement hybrid technology in an existing drivetrain, while adapting the existing components as required. The functional variability of hybrid technology, however, permits a range of possible implementations and the control calibration tasks themselves need to be well structured concerning hand-over, traceability and robustness.
Technical Paper
2014-10-13
Stefan Geng, Thomas Schulte
Hybrid electric powertrains are developed for reducing the fuel consumption and the emission of carbon dioxide. In order to achieve a reduction in comparison to conventional vehicles, an improved efficiency of the overall system is required. It depends on the powertrain topology, its components and the applied control strategy. For testing and improving the control strategy in terms of the overall system efficiency, Hardware-in-the-Loop (HIL) simulation can be applied. Thereby, a real-time simulation of the powertrain is used to emulate the behavior of the actuator and sensor signals in order to operate the corresponding electronic control units in a virtual test environment [1], [2]. The development of real-time capable powertrain models is a time-consuming task, due to high dynamics and switching frequencies of the electrical subsystem, comprising the electric drive, inverter and battery and due to the immense diversity of powertrain configurations, comprising the transmission, the combustion engine, the electric drives, etc.
Technical Paper
2014-10-13
Abdelmajid Ait Taleb, Ali Chaaba, Mohamed Sallaou
In the field of machinery, epicyclic gear trains play a fundamental role in power transmission lines. Their use is very wide and varied and they can realize the function of a mechanism as a “differential" or as a mechanism to reduce or increase speeds. For example, the epicyclic gear trains equip a large number of vehicles transmission such as electric and hybrid cars and heavy vehicles, these epicyclic gear trains are integrated especially in continuously variable power split transmissions. The mechanical efficiency assessment of transmissions integrating one or more epicyclic gear trains requires the knowledge of the efficiencies of components setting up the transmission, in particular that of the epicyclic gear trains. The efficiency of these mechanisms is commonly defined as the ratio of the output power by the input one. For a planetary gear train with three active shafts, which operates as a differential system, the definition of the efficiency will not change, but, it is necessary first to identify the powers flow running between its links.
Technical Paper
2014-10-13
Fuyuan Yang, Lei Du, Changsheng Yao, Jiaen Du, Ping Yu
The efficiency of traction motor affects the overall efficiency of city buses which most of time creep among jammed city traffic. The low speed and torque operating condition deviate from the high-efficiency region of electric motor. This paper discusses whether it is possible to improve the motor efficiency by a two-speed transmission and if so, to what extent. In this paper, based on the China Bus Urban Cycle, an 8-meter electric bus is studied, and the comparison of motor efficiency between two different configurations is made: direct drive and drive through a two-speed transmission. In the ‘direct drive’ configuration, the traction motor drives the main reducer directly, while in the other configuration installed a two-speed transmission between. Apart from that, all other specifications are the same. The study is conducted via modeling and simulation in Matlab/Simulink environment. In the simulation of both configurations, models of driver, traction motor, two-speed transmission, the I-curve of braking forces distribution and vehicle controller are built.
Technical Paper
2014-10-13
Jonathan Hall, Hannes Marlok, Michael Bassett, Marco Warth
In 2012 MAHLE Powertrain unveiled a range-extended electric vehicle (REEV) demonstrator, which is based on a series hybrid configuration, and uses a battery to store electrical energy from the grid. Once the battery state of charge (SOC) is depleted a gasoline engine (range extender) is activated to provide the energy required to propel the vehicle. As part of the continuing development of this vehicle, MAHLE Powertrain has logged vehicle data in real world driving situations with the aim of understanding the actual usage a REEV under non-laboratory test conditions. The vehicle is instrumented with a data acquisition system to measure physical parameters, for example coolant temperatures, as well as CAN-based data from the engine and vehicle management systems. The logged data has been analysed, using in-house tools, to establish the effect of environmental factors such as ambient temperature, human behavioural characteristics and variation in usage patterns on the efficiency and operational behaviour of the REEV system as a whole.
Technical Paper
2014-10-13
Boru Jia, Zhengxing Zuo, Huihua Feng, Guohong Tian, A. P. Roskilly
Free-piston engine generator (FPEG) is a novel type of energy conversion device, which integrates a linear combustion engine and a linear electrical machine into a single unit. As an alternative to conventional engines, FPEG is a promising power generation system due to its simplicity and high thermal efficiency and has attracted considerable research interests recently. This paper presents the development for a spark-ignited free-piston engine generator prototype which was rated to 3kW power output, and the designation of major sub-systems is introduced. The electrical linear machine is operated as a linear motor to start the engine and switched to a generator after successful ignition. Closed-loop control strategy was investigated and implemented for the starting process with a constant force provide by the linear machine. Ignition is one of the most crucial problems for the generating process, thus a unique control sub-system to generate ignition signals at the correct ignition timing based on the piston position was completed.
Technical Paper
2014-09-30
Dhiraj Dashrat Salvi
ABSTRACT- Braking system is having a key importance in vehicle safety & handling stability. In this research paper I had developed a circuit model of Anti-lock braking system where the operating medium is hydra-pneumatic. A solenoid operated modulator valve consisting two 2/2 valves is connected in line with the air cylinder & hydraulic master cylinder assembly. Using methodology of response time calibration time taken to modulate hydraulic pressure w.r.t pneumatic pressure is evaluated. The signal input to the modulator valve is given by the Electronic controlled input (ECU). All results obtained is exported to an excel file using Data Acquisition software with pressure myograph system. It gives easy and intuitive readings based on the signal programmed from ECU for various inputs (i.e. ramp, step) .The signal are programmed for various inputs in order to check the fidelity of the circuit. These readings are easily customized to get the optimum graphs. The response time evaluated from the calibrated data is compared with benchmark or standard set by CMVR to meet the regulation.
Technical Paper
2014-09-30
Sunil raj, S Ravi Shankar
Braking system is one of the very important in the automotive system. The purpose of the braking system is to stop or slow the vehicle when required. Deceleration of the vehicle is done due to the friction between Brake drum and Brake lining. Brake drum converts kinetic energy into heat energy and it dissipates the heat. The amount of heat depends on the weight of the vehicle and speed at the moment the brakes are applied. The brake drum material must be able to dissipate the heat as much as possible and to resist the high thermal stresses generated during repeated thermal cycling. Traditionally brake drums are manufactured using grey cast iron to meet thermal conductivity and vibration damping characteristics resistance to thermal shock and cycling, wear resistance and easy of production. The main purpose of using grey cast iron in brake drum is because it has good thermal conductivity property and wear resistance. Aluminum is the other metal which has better thermal conductivity compared to cast iron but it has very bad wear resistance compared to grey cast iron.
Technical Paper
2014-09-30
Sivanandi Rajadurai, Prakash Krishnan, Naveen Sridharan, Manimaran Sethuramasubramaniyam
Canning is the process of mounting the support mat & substrate into the shell. Canning is a very important aspect in the catalyst converter design, especially with the current trend of using thinner wall and ultra-thin wall substrates. Considering the reduced isostatic and shear strengths of thin and ultra thin wall substrates, conventional canning technique will reduce canning durability where the mat or the substrate or the shell may be damaged. This brings into requirement a controlled canning process which shall not disturb the canning durability. The paper shall explain an established controlled canning process developed at a very low investment yet with effective outputs using a DOE methodology for choosing the best suited practices for the respective parts for canning. The outputs were cross verified using push out test and GBD verification using destructive methodology and the results obtained were competitive.
Technical Paper
2014-09-30
Sivanandi Rajadurai, Guru Prasad Mani, Sundaravadivelu M, Kavin Raja
Simulation’s drive towards reality boundary conditions is a toughest challenge. Experience has shown that often the most significant source of error in thermal and dynamic analyses is associated within specified boundary conditions. Typically, validating the system by considering both thermal and dynamic loads with predefined assumptions is time consuming and inconclusive when confronted to reality boundary conditions. Thus, solution comes in unique way of combining thermal and dynamic loads with specified boundary conditions will convey computational results closer to real scenario. As a consequence, strain concentrated regions due to thermal expansion are aggregated more, when coupled with dynamic loading. The stress generated by the coupled analyses will proves to be critical in concerning the durability issue of the hot end system. These conditions were evaluated by a finite elements model through a linear and non-linear approach, which had its results summarized.
Technical Paper
2014-09-30
Xianjian Jin, Guodong Yin, Youyu Lin
Knowledge of vehicle dynamics variables is very important for vehicle control systems that aim to improve handling characteristics and passenger safety. However for both technical and economical reasons some fundamental data (e.g., Lateral tire-road forces and vehicle sideslip angle) are not measurable in a standard car. This paper proposes a novel Interacting Multiple Model Filter-Based method to estimate lateral tire-road forces by utilizing real-time measurements. The method uses measurements (yaw rate, roll rate, accelerations, steering angle and wheel speed) only from sensors which have already been integrated in modern cars. The estimation method of lateral tire-road forces is based on an interacting multiple model (IMM) filter that integrates in-vehicle sensors of in-wheel-motor-driven electric vehicles to adapt multiple vehicle-road system models to variable driving conditions. Considering extended roll dynamics and load transfer, a four-wheel nonlinear vehicle dynamics model (NVDM) is built.
Technical Paper
2014-09-30
Iman Hazrati Ashtiani, Mehrnoosh Abedi
Road trains have been applied as one of the efficient ways for transportation of goods in different countries like United States, Canada, Brazil and Australia. These long vehicles have a wide variety in length or towing systems like fifth wheel or dolly draw-bar and based on specific measured and regulation could be authorized to move in specific roads. In order to avoid hazard and danger in case of accidents of these vehicles, safety performance of a specific type of these vehicles, called B-train, is investigated in this paper. A Multi-Body Dynamics (MBD) model of a B-train, which consists of a prime mover and two trailers coupled by fifth wheels, are simulated in first phase of study. The developed dynamic model is capable of simulating required tests as well as SAE lane change and constant radius turn for roll and yaw stability analysis and safety evaluation. As far as transportation of fuel or other hazardous liquid are a common usage of B-train vehicles, the effects of liquid fill level variation are also considered in this research.
Technical Paper
2014-09-30
Vladimir V. Vantsevich, Jeremy P. Gray, Dennis Murphy
Through inverse dynamics-based modeling and computer simulations for a 6x6 unmanned ground vehicle in stochastic terrain conditions, this paper analytically presents a coupled impact of different driveline system configurations and a suspension design on vehicle dynamics, including vehicle mobility and energy efficiency. A new approach in this research work involves an estimation of each axle contribution to the level of potential mobility loss/increase and/or energy consumption increase/reduction. As it is shown, the drive axles of the vehicle interfere with the vehicle’s dynamics through the distribution of the wheel’s normal reactions and wheel torques. The interference causes the dynamics of the independent systems to become operationally coupled/fused, and thus diminishes the vehicle’s mobility and energy efficiency. The analysis is achieved by the use on new mobility indices and energy efficiency indices which are functionally coupled/fused. Four possible scenarios are considered to trade between mobility and energy efficiency improvements by re-distributing power between the drive axles in severe/extreme terrain conditions, including poor mu-conditions, and high longitudinal and lateral slopes.
Technical Paper
2014-09-30
Yiting Kang, Subhash Rakheja, Wenming Zhang
Different types of axle suspension systems have evolved for large size mining trucks to achieve improved attenuation of terrain-induced whole-body vibration (WBV) transmitted to the operator and to attain higher operating speeds. The hydro-pneumatic struts are increasingly being used together with different linkage configurations, which could yield widely different kinematic and dynamic properties and thereby the ride and handling performance of the vehicle. This paper presents comprehensive analyses of the different independent front suspension linkages that have been implemented in various off-road vehicles, namely a composite linkage Macpherson strut type suspension (CLT), a candle type suspension (CT), a longitudinal arm type suspension (LAT), and a double wishbone type suspension (DWT). The relative performance analyses are evaluated on the basis of handling dynamics of a 190 tons mining truck. The kinematic variations in camber, caster, inclination angle, toe-in and horizontal wheel center displacements of different linkage suspensions are synthesized via wheel bounce excitations in the MapleSim platform.
Technical Paper
2014-09-30
Shaoyun Sun, Yin-ping Chang, Xinyu Wang, Qiang Fu, Kelong Lu, Zuofeng Pan, Bo Li, Heinz Friz
A big challenge for the aerodynamic optimization of trucks is the limited availability of wind tunnels for testing full scale trucks. FAW wants to introduce a development process which is mainly based on CFD simulation in combination with some limited amount of wind tunnel testing. While accuracy and maturity of CFD simulation for truck aerodynamics has been demonstrated in recent years, a complete validation is still required before committing to a particular process. The CFD tools involved in this validation are Star CCM+ and PowerFLOW. Since there is currently no wind tunnel available in China for the testing of full scale trucks, a 70% scale model is built for testing in the Shanghai Automotive Wind Tunnel Center. Drag and surface pressures are measured for providing a good basis for comparison to the simulation results. The simulations are performed for the scale model geometry as well as for the full scale geometry of the fully detailed truck. As a completion of this validation study a test of the full scale truck with a shortened trailer in a suitable wind tunnel in Europe is planned as future work.
Technical Paper
2014-09-30
Helena Martini, Peter Gullberg, Lennart Lofdahl
Nowadays, much focus for the vehicle manufacturers is put on improving the energy efficiency of their products. The aerodynamic drag constitutes one major part of the total driving resistance for a vehicle driving at higher speeds. In fact, above approximately 80km/h the aerodynamic drag is the dominating resistance acting on a truck. Hence the importance of reducing this resistance is significant. Cooling drag is one part of the total aerodynamic drag, which arises from air flowing through the heat exchangers and the irregular underhood area. When using Computational Fluid Dynamics (CFD) in the development process it is of great importance to ensure that the methods used are accurately capturing the physics of the flow. This paper deals with comparative studies between CFD and wind tunnel tests. In this paper, two comparative studies are presented. One is a comparison between cooling performance simulations and climate wind tunnel measurements; the other study is a comparison between external aerodynamics CFD simulations and wind tunnel measurements.
Technical Paper
2014-09-30
Marc Ratzel, Warren Dias
Multiple engineering disciplines are considered in the development process of modern vehicles. This includes disciplines such as aerodynamics and structural dynamics. Often, these disciplines are applied in isolation, that is, without the consideration of interactions between disciplines. But in order to accurately represent the physical environment in which these designs and vehicles operate, it becomes important to consider the interaction effects. Interaction effects can be considered by including the effects of the different disciplines in a sequential manner, such as, determining the aerodynamic loads with a computational fluid dynamics (CFD) solver and then using the computed forces as boundary conditions in a structural analysis solver to determine displacements and stresses. However, for certain applications where this sequential modeling approach is not representative, the multiple disciplines can be analyzed in a co-simulation environment. An example of this would be the fluttering of an automotive hood under driving conditions.
Viewing 1 to 30 of 17710