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Viewing 1 to 30 of 445
2017-03-28
Technical Paper
2017-01-1151
Yosuke Suzuki, Norihiro Yamamura, Hiroatsu Endo, Shinichi Baba, Tomoyuki Miyazaki, Akiko Nishimine, Michitaka Tsuchida, Kenji Miyasaka
The automotive industry has been researching and developing the green vehicle in response to the energy conservation and environmental problems recently. Especially, developing plug-in hybrid vehicles as the green vehicle is very active among many automobile manufacturers. The demand for plug-in hybrid vehicles is increasing compared to hybrid vehicles. A plug-in hybrid system and a transaxle, which enable vehicles to run as electric vehicles even in need of a high driving force for a powerful acceleration, are being required. We have developed a “Dual Motor Drive System” which enables vehicle to run with two motors by adding minimum number of parts as possible onto P610, which is the transaxle of the 4th generation Prius. For this system, we have used a generator as a motor which has been done by adopting a one-way clutch between an engine and a planetary gear. As a result, the new Toyota plug-in hybrid vehicle has achieved a powerful electric drive.
2017-03-28
Technical Paper
2017-01-1150
Kenta Kumazaki, Tooru Matsubara, Nobufusa Kobayashi, Shunya Kato, Kazuyuki Shiiba, Ikuo Ando, Hiromichi Kimura, Hiroatsu Endo
Toyota Motor Corporation has developed Multi Stage Hybrid System for Lexus flagship coupe LC500h, which is designed to achieve an excellent balance between fuel economy and acceleration performance. Multi Stage Hybrid Transmission has four-stage shift device straight after power split device with generator and motor. Compared with the existing Hybrid System, fuel economy is improved by reducing electric loss in optimal gears depending on driving range, and acceleration performance is improved by increasing driving force at low and medium vehicle speed in lower gears. In addition, the wider range of power split device cooperated with four-stage shift device enables not only continuously variable transmission mode but also ten-speed automatic transmission mode. At middle and high load operation, direct shift feeling improves driving pleasure as hybrid vehicle.
2017-03-28
Technical Paper
2017-01-1099
Seiji Masunaga, Terufumi Miyazaki, Yohei Habata, Kazuhiko Yamada, Yoshio Hasegawa, Takahiro Kondo, Ichiro Kitaori, Akira Takeichi
Toyota Motor Corporation has developed an innovative 10-speed longitudinal automatic transmission called the Direct Shift-10AT. The Direct Shift-10AT is a significant contributor to the excellent dynamic performance of the Lexus LC500. A wide gear spread with close gear ratios allows for rhythmical shifting, smooth and powerful acceleration from a standing start, along with quiet and relaxed high-speed driving due to low engine speeds. The lock-up area is expanded to a wider range of vehicle speeds (excluding low-speed regions such as when starting off), by the adoption of a multi-plate lock-up clutch, a newly developed torque converter, and a high-precision controller. As a result, the shift control can match the driver’s intended operation more directly because the main cause of the response delay (transient changes in engine speed (flare)) is eliminated. Furthermore, fuel economy is improved due to the adoption of low friction clutches.
2017-03-28
Technical Paper
2017-01-1094
Yusuke Nakade, Atsushi Kamada, Koki Ueno, Mikine Kume, Kouji Sakaguchi
Shift selection devices are desired to be flexible for design and layout, in order to realize the next generation of cockpits for Lexus vehicles. In addition, refined shift operation feelings are also required to be suitable for Lexus vehicles. To meet these demands, the Lexus LC500 has been equipped with a shift-by-wire system, which replaces the mechanical linkage between the shift selector and transmission with electrical signals and an actuator. This shift-by-wire system will be installed in a wide variety of Lexus powertrain lineup, including conventional gas vehicles and hybrid vehicles. Therefore, the next generation shift-by-wire system for Lexus has been developed with high reliability and applicability. This technology will be essential when autonomous driving and autonomous parking systems are realized in the near future.
2017-03-28
Technical Paper
2017-01-1093
Yosuke Michikoshi, Daisuke Kusamoto, Hirofumi Ota, Masashi Ikemura, Noritaka Takebayashi, Ike Nobukazu, Yasuda Takashi, Inoue Ryohei
Because of environmental issues such as reducing carbon dioxide and tightening fuel economy regulations for automobiles, it has become essential to develop vehicles with superior fuel efficiency and cleaner emissions. At the same time, the demand of the basic performance characteristics such as driving performance and NVH is increasing. Toyota Motor Corporation has developed a new eight-speed automatic transaxle (UA80) which has realized these requirements at a high level, and is adopted into the new Siena and Highlander. UA80 is the first Toyota transaxle which incorporates the TNGA concept. It has high level competitiveness in wide torque range from L4 engine to V6 engine by using both optimization and standardization of main components. Additionally it has a superior installation performance by optimizing the transaxle size and arrangement and achieved a low gravity center. It contributes to vehicle’s attractiveness by improving driving performance, NVH and design.
2017-03-28
Technical Paper
2017-01-1173
Shunya Kato, Ikuo Ando, Koji Ohshima, Tooru Matsubara, Yasuhiro Hiasa, Hideki Furuta, Yuma Mori
Lexus Hybrid Drive (LHD), that combines a gasoline engine and electric units has been implemented into luxury rear wheel drive vehicles such as LS, GS, IS and RC, and has widely spread around the world since 2005. To lead a future chapter of Lexus, in 2017, Lexus launched a new hybrid luxury coupe LC500h to enhance its brand and competitiveness. On the development of LC500h, LHD also made a major improvement and was pioneered to the next level as a powertrain. This new powertrain was named Multi Stage Hybrid System which maximizes the performance, drivability and efficiency with a newly developed transmission, electric units and driving control logics. This paper explains the new LHD with Multi Stage Hybrid System which achieved both high power performance and luxury drivability while maintaining environmental performance of fuel economy and emission, and introduces the technology which achieved direct feel drivability.
2017-03-28
Technical Paper
2017-01-1188
Daisuke Hayashi, Atsushi Ida, Shota Magome, Takahisa Suzuki, Satoshi Yamaguchi, Ryosuke Hori
 Higher power density is needed to make compact and cost-competitive polymer electrolyte membrane (PEM) fuel cell stack. Key challenge to design a high power density fuel cell is to reduce oxygen transport loss caused by liquid water inside gas diffusion layer (GDL). However, liquid water transport through catalyst layer to GDL, GDL to channel under operating condition is not fully understood because of GDL’s small pore sizes (0.1~100μm), complex structure (formed of 2 porous layers: substrate layer and micro porous layer) and transport phenomena. To elucidate relationship between cell performance and water distribution, liquid water visualization technique by Synchrotron X-ray (SPring-8) and a Computational Fluid Dynamics (CFD) based simulation were developed and analyzed using design of experiments (DOE).
2017-03-28
Technical Paper
2017-01-0586
Hayato Shirai, Hayato Nakada, Akio Matsunaga, Hiroyuki Tominaga
In real-world automotive control, there are a lot of constraints to be considered. In order to explicitly treat the constraints, we introduce a model-prediction-based algorithm called a reference governor (RG). The RG generates modified references so that predicted future variables in a closed-loop system satisfy their constraints. One merit of introducing the RG is that effort required in control development and calibration would be reduced. In the preceding research work by Nakada et al., only a single reference case was considered. However, it is difficult to extendedly apply it to more complicated systems with multiple references such as the air path control of a diesel engine, which suffers from interference between boosting and exhaust gas recirculation (EGR) systems. Moreover, in the control, multiple constraints need to be considered to ensure hardware limits and control performance.
2017-03-28
Technical Paper
2017-01-1408
Satoshi Kozai
The goal of both automakers and vehicle users is to minimize the negative impacts of vehicles on society, such as traffic accidents, not only on the road but parking area, optimizing the enjoyment of using a car, comfort, and usability. To realize this, we have already provided automatic brake system (ICS) for static obstacles in parking area. We have also developed the Rear Cross Traffic Auto Brake (RCTAB) system, which detects a vehicle approaching from the sides when backing out of a parking area. We decided RCTAB system specifications based on two information “Approaching vehicle speed in parking area” and “Maximum backing speed”. RCTAB system structure consists of Radar which shared with “Blind Spot Monitor” and ECU which shared with “ICS Computer”. The radar detects the approaching vehicle. The ICS Computer judge Collision prediction and request “Braking Force” and “Driving Force” to Brake and Engine Computer.
2017-03-28
Technical Paper
2017-01-1239
Naoya Take, Takuya Kadoguchi, Masao Noguchi, Kimihiko Yamanaka
Power modules are used to operate three-phase alternative motors in hybrid vehicles and electric vehicles. The good fuel efficiency and high power density are requested in the field of hybrid vehicles. To achieve this goal, the miniaturization of power module will be necessary. This trend may make current density, which is operated by insulated gate bipolar transistors (IGBTs) and Free wheel diodes (FWDs), higher in power modules. Solder is often used as the joint material of power modules. It is known that a current density larger than 10 kA/cm2 causes solder electromigration which exchanges momentum from electrons to metallic atoms .This phenomenon may cause delamination of the joint area and void formation. In addition, the ambient temperature has an influence on electromigration. The temperature of an engine compartment is high, so it is likely to cause electromigration.
2017-03-28
Technical Paper
2017-01-1288
Noriko Shisa, Shinsuke Ishihara, Yougui Huang, Mikio Asai, Katsuhiko Ariga
Despite methanol is toxic to human health and causes serious damage to automobile engine and components in fuel system, there are increasing distribution of methanol-containing gasoline in some area. Methanol demonstrates similar chemical properties to ethanol (which is established as an additive to gasoline), so that it is challenging to identify methanol-containing gasoline without performing proper chemical analysis (e.g., GC-MS). In this study, we aim to develop low-cost, portable, and easy-operation sensor that selectively changes its color (from red purple to blue purple) in response to methanol-containing gasoline. The colorimetric sensor will be useful for automobile users to avoid unexpected refueling of methanol-containing gasolines. Our methanol sensor is a thin film of clay mineral (layered double hydroxide, LDH) embedded with dye molecules (oxoporphyrinogen, OxP).
2017-03-28
Technical Paper
2017-01-1545
Susumu Terakado, Takafumi Makihara, Takashi Sugiyama, Kazuhiro Maeda, Kenji Tadakuma, Kentaro Tsuboi, Masashi Iyota, Kazuyoshi Kosaka, Sadato Sugiyama
Though aeroacoustic performance of passenger vehicle under steady state has been improved, fluctuating cabin noise that passengers are more sensitive to has not been researched enough. Previous works on cabin noise in unsteady flow was conducted by road tests and wind tunnel test with devices that produce turbulent flow. Considering the difficulty in setting the condition and data reproducibility in road test, wind tunnel test is preferable.However, wind tunnel test with turbulence generating devices has also difficulty in reproduction of natural wind. Though previous researches has been conducted mainly under flow with yaw angle fluctuation, flow velocity fluctuation has not been considered because these two factors have not been generated at the same time by existing facilities. Additionally, high turbulence intensity and high frequency fluctuation of flow in road condition are not reproduced together either.
2017-03-28
Technical Paper
2017-01-1398
Yoshiyuki Hatakeyema
Because drowsy driving causes serious traffic accidents, the prevention technologies are highly required. In this study, we propose a drowsy driving prediction method based on eye opening time. The challenge of this method is to predict driver’s strong drowsiness before they feel sleepy. We pay attention to eye opening movement during driving, because overlooking hazards is one of the causes of traffic accident and is closely related to recognition and drowsiness. Hence, we attempt to predict driver’s drowsiness from eye opening time. At first, we form hypotheses of drowsiness and eye opening time based on the results of previous studies. We assume that the standard deviation of eye opening time (SDEOP) indicates the driver’s drowsiness and consider two types of transition, that is, the increase and decrease of SDEOP. In order to confirm our hypotheses, we investigate a relation between drowsiness and SDEOP.
2017-03-28
Technical Paper
2017-01-0704
Noriyuki Takada, Takeshi Hashizume, Terutoshi Tomoda, Kazuhisa Inagaki, Kiyomi Kawamura
Generally, soot emission is increased in smaller bore-size diesel engine than larger one because spray-impingement on cavity wall is more significant, while keeping at constant specific output power. The objective of study is to clarify what constraints are necessary for engine/nozzle specifications and injection conditions to achieve the same combustion characteristics (such as heat release rate and emissions) in diesel engines with different bore sizes. In the first report, ‘Geometrical similarity’ was applied to the two different bore-size engines, which have similarity shape of piston cavity. Then, smoke of smaller engine is larger. This is because air entrainment decreases due to shrinking of spray angle. A new spray design method has been proposed to suppress soot emission called as ‘Spray characteristics similarity’.
2017-03-28
Technical Paper
2017-01-1539
Vinh Long Phan, Hiroshi Tanaka, Takaaki Nagatani, Mikio Wakamatsu, Tsuyoshi Yasuki
Interior noises in high frequency of a passenger vehicle due to exterior wind noises induced by turbulent flow around the vicinity of the front pillars and front side glass are one of the most impact factors on customer feelings of riding comfort and their perception of quality of vehicle. In order to reduce such undesirable interior noises during vehicle development process, a calculation and visualization method for exterior wind noise with an acceptable computational cost and adequate accuracy is required. In this paper an index for prediction of the strength of exterior wind noise, referred to as Exterior Noise Power (ENP), is developed based on an assumption that the acoustic power of exterior wind noise can be approximated by the far field acoustic power radiated from vehicle surface.
2017-03-28
Technical Paper
2017-01-1328
Yoshiteru Tanaka, Jun Yamamura, Atsushi Murakawa, Hiroshi Tanaka, Tsuyoshi Yasuki
When vehicles run on the flooded road, water enters into the engine room and sometimes reaches to the position of air inlet duct and electrical parts and causes the reliability problems. Numerical simulation is effective tool for this phenomenon because it can not only evaluate the water level before experiment but also identify the intrusion routes. Recently, the gap around the engine cooling modules tends to be narrower and the undercover tends to be larger than before in order to enhance the vehicle performance (e.g., aerodynamics, exterior noise). Leakage tightness around the engine room becomes higher and causes to increase the buoyancy force from the water. Therefore the vehicle attitude change is giving a greater impact on the water level. This paper describes the development of water level prediction method while running on the flooded road by using the coupled multi body and fluid dynamics analysis.
2017-03-28
Technical Paper
2017-01-0919
Takeru Yoshida, Hiromasa Suzuki, Yuki Aoki, Naohiro Hayashi, Kenichi Ito
Emission regulations in many countries and regions around the world are becoming stricter in reaction to the increasing awareness of environment protections, and it is now required to improve the performance of catalytic converters to achieve these goals. A catalytic converter is composed of a catalytically active material coated onto a ceramic honeycomb-structured substrate. Honeycomb substrates play the role of ensuring intimate contact of the exhaust gas and the catalyst within the substrate’s flow channels. In recent years, high-load test cycles have been introduced which require increased robustness to maintain low emissions during the wide range of load changes. Therefore, it is extremely important to increase the probability of contact between the exhaust gas and catalyst.
2017-03-28
Technical Paper
2017-01-1278
Keisuke Isomura
Heretofore, the interest in prevention of global warming is high in the automobile industry. And the development of the green cars (HV, EV etc.) advances rapidly to reduce CO2 (carbon dioxide) discharge when running. In the announcement of "Toyota environmental challenge 2050", we were committed to continuing toward the year 2050 with steady initiatives in order to realize sustainable development together with society. As it is declared here, our responsibilities aren’t only to reduce CO2 discharge when running but to reduce life cycle CO2 discharge and use resources effectively by refusing, reducing, reusing and recycling (4R). Although the green cars decrease CO2 discharge when running, most of those increase CO2 discharge when manufacturing and increase resources risks (price fluctuations, deflection of the resource production, depletion etc.). For example, the driving motor uses the magnet including rare-earths (Nd, Dy etc.).
2017-03-28
Technical Paper
2017-01-1118
Isamu Hachisuwa, Naoki Kato, Daisuke Kusamoto, Hideki Miyata, Takuya Okada, Hitoshi matsunaga, Takamitsu Kuroyanagi, Makoto nakazuru
Increasingly stringent environmental regulations, such as reducing carbon dioxide emissions and increasing fuel economy targets, have made it essential to develop vehicles with superior fuel efficiency and cleaner emissions. At the same time, the demand for improved vehicle characteristics such as driving performance and NVH are increasing. Toyota Motor Corporation has developed a new eight-speed automatic transaxle (UA80) which has realized these requirements at a high level, and is adopted into the new Sienna and Highlander. UA80 is the first Toyota transaxle which incorporates the TNGA concept. It has high level competitiveness in a wide torque range from L4 engines to V6 engines by using both optimization and standardization of main components. Additionally, UA80 has achieved an increased ease of installation by optimizing the transaxle size and arrangement while still achieving a low gravity center.
2017-03-28
Technical Paper
2017-01-1549
Taro Yamashita, Takafumi Makihara, Kazuhiro Maeda, Kenji Tadakuma
In recent years, the automotive manufacturers have been working to reduce fuel consumption in order to cut down on CO2 emissions, promoting weight reduction as one of the fuel saving countermeasures. On the other hand, this trend of weight reduction is well known to reduce vehicle stability in response to disturbances. Thus, automotive aerodynamic development is required not only to reduce aerodynamic drag, which contributes directly to lower fuel consumption, but also to develop technology for controlling unstable vehicle behavior caused by natural wind. In order to control the unstable vehicle motion by external contour modification, it is necessary to understand unsteady aerodynamic forces that fluctuating natural wind in real-world environments exerts on vehicles. In the past, some studies have reported the characteristics of unsteady aerodynamic forces induced by natural winds, comparing to steady aerodynamic forces obtained from conventional wind tunnel tests.
2017-03-28
Technical Paper
2017-01-0676
Naoto Hayashi, Akimitsu Sugiura, Yuya Abe, Kotaro Suzuki
In recent years, from a viewpoint of global warming and energy issues, improving vehicle fuel economy to reduce CO2 emission is required. One of the improvement ways is to enhance the engine thermal efficiency, and for that, automakers have been developing the technologies of high compression ratio, dilute combustion such as exhaust gas recirculation (EGR) and lean combustion. Since the excessive dilute combustion causes the failure of flame propagation, combustion promotion by intensifying in-cylinder turbulence has been indispensable. However, instability of flame formation by the gas flow fluctuation between combustion cycles is becoming an issue. Therefore, achieving stable flame formation and propagation under a high dilute condition is important technology. DENSO CORP. has developed the new ignition technology to be able to form flame surely under variable gas flow velocity conditions.
2017-03-28
Technical Paper
2017-01-1598
Koichi Go, Takahiro Hirano, Tatsuya Miyoshi, Daisuke Sato
Fuel consumption and CO2 emission regulations for vehicles, such as the Zero Emission Vehicle (ZEV) Regulation, motivate renewable energy technologies in the automotive industry. Therefore, the automotive industry is focused on adopting solar charging systems. Some vehicles have adopted solar energy to power in the ventilation system, but these vehicles do not use solar energy to power the drivetrain. One important issue facing the design of solar charging systems is the low power generated by solar panels. Compared to solar panels for residential use, solar panels for vehicles can’t generate as much power because of size and weight limitations. Also, the power generated by solar panels can be extremely affected depending on differences in solar radiation among the cells. Therefore, Toyota has developed a solar charging system that can use solar energy for driving the Prius PHV. This system can efficiently charge the hybrid battery with the low power generated by the solar panel.
2016-10-17
Technical Paper
2016-01-2353
Kazunori Harima, Shinji Tsuchiya, Takuro Morino, Yuji Nagasawa
Abstract A CVT belt is composed of multiple elements and layered rings. Each of these component parts generates loss, including relative slippage caused by the geometrical relationship between the elements and innermost ring layer. An effective way of increasing CVT efficiency is to reduce this slippage. However, since the relative slippage also controls whether the rings transmit constant torque at all times, reducing the slippage will also have an effect on the torque transmission performance of the rings. Therefore, to improve CVT efficiency by reducing the relative slippage, it is first necessary to analyze the changes to torque transmission. However, this slippage is a phenomenon of the inner portion of the belt and it is extremely difficult to identify the internal thrust force when actual load is applied.
2016-10-17
Technical Paper
2016-01-2198
Chikara Dodate, Sachio Mori, Masato Kawauchi, Rio Shimizu
Abstract Computational fluid dynamic (CFD) is widely used to develop engine combustion. Especially the in-cylinder spray calculation is important in order to resolve the issues of direct injection gasoline engines (e.g., particulate matter (PM) and oil dilution caused by fuel wetting on the cylinder walls). Conventional spray calculation methods require fitting based on measurements of spray characteristics such as penetration and droplet diameter (i.e., the Sauter mean diameter (SMD)). Particularly in the case of slit nozzle shapes that widen from the inlet to the outlet to form a fan-shaped spray, fitting the shape of spray is a complex procedure because the flow inside the nozzle is not uniform. In response, a new calculation method has been developed that eliminates the need for spray shape fitting by combining calculations of the Eulerian multiphase and the Lagrangian multiphase.
2016-10-17
Journal Article
2016-01-2204
Takafumi Mori, Masanori Suemitsu, Nobuharu Umamori, Takehisa Sato, Satoshi Ogano, Kenji Ueno, Oji Kuno, Kotaro Hiraga, Kazuhiko Yuasa, Shinichiro Shibata, Shinichiro Ishikawa
Abstract Torque loss reduction at differential gear unit is important to improve the fuel economy of automobiles. One effective way is to decrease the viscosity of lubricants as it results in less churning loss. However, this option creates a higher potential for thin oil films, which could damage the mechanical parts. At tapered roller bearings, in particular, wear at the large end face of rollers and its counterpart, known as bearing bottom wear is one of major failure modes. To understand the wear mechanism, wear at the rolling contact surface of rollers and its counterpart, known as bearing side wear, was also observed to confirm the wear impact on the tapered roller bearings. Because gear oils are also required to avoid seizure under extreme pressure, the combination of a phosphorus anti-wear agent and a sulfurous extreme pressure agent are formulated.
2016-10-17
Technical Paper
2016-01-2276
Toyoharu Kaneko, Kazuo Yamamori, Hiroyuki Suzuki, Ko Onodera, Satoshi Ogano
Abstract Increasing numbers of vehicles equipped with downsized, turbocharged engines have been introduced seeking for better fuel economy. LSPI (low speed pre-ignition), which can damage engine hardware, is a potential risk of the engines. We reported that engine oil formulation affects frequency of LSPI events, and formulating magnesium detergents into oil is a promising option to prevent LSPI events. From the viewpoint of achieving better fuel economy by engine oil, lowering viscosity is being required. However, it causes reduced oil film thickness and will expand boundary lubrication condition regions in some engine parts. Hence, a technology to reduce friction under boundary lubrication becomes important.
2016-04-05
Technical Paper
2016-01-1674
Takao Kobayashi, Etsuo Katsuyama, Hideki Sugiura, Eiichi Ono, Masaki Yamamoto
Abstract The research described in this paper aimed to study the cornering resistance and dissipation power on the tire contact patch, and to develop an efficient direct yaw moment control (DYC) during acceleration and deceleration while turning. A previously reported method [1], which formulates the cornering resistance in steady-state cornering, was extended to so-called quasi steady-state cornering that includes acceleration and deceleration while turning. Simulations revealed that the direct yaw moment reduces the dissipation power due to the load shift between the front and rear wheels. In addition, the optimum direct yaw moment cancels out the understeer augmented by acceleration. In contrast, anti-direct yaw moment optimizes the dissipation power during decelerating to maximize kinetic energy recovery. The optimization method proved that the optimum direct yaw moment can be achieved by equalizing the slip vectors of all the wheels.
2016-04-05
Technical Paper
2016-01-1668
Hideki Fukudome
Abstract This study analyzed the longitudinal vibration of a vehicle body and unsprung mass. Calculations and tests verified that longitudinal vibration can be reduced using in-wheel motors, which generate torque very quickly. Despite increasing demand for measures to enhance ride comfort considering longitudinal vibration, this type of vibration cannot be absorbed or controlled using a conventional suspension. This paper describes the reduction of vehicle longitudinal vibration that cannot be controlled by conventional actuators.
2016-04-05
Technical Paper
2016-01-1677
Hiroshi Himeno, Etsuo Katsuyama, Takao Kobayashi
Abstract Electric vehicles (EVs) are attracting attention due to growing awareness of environmental issues such as fossil fuel depletion and global warming. In particular, a wide range of research has examined how direct yaw moment controls (DYCs) can enhance the handling performance of EVs equipped with multiple in-wheel motors (IWMs) or the like. Recently, this research has focused on reducing energy consumption through driving force distribution control. The first report proposed a method to minimize energy consumption through an efficient DYC for extending the cruising range of a vehicle installed with four IWMs, and described the vehicle behavior with this control. Since motors allow high design flexibility, EVs can be developed with a variety of drive systems. For this reason, various driving force distribution control methods can be considered based on the adopted system.
2016-04-05
Technical Paper
2016-01-1609
Yusuke Nakae, Jun Yamamura, Hiroshi Tanaka, Tsuyoshi Yasuki
Abstract The unsteady aerodynamic loads produced due to vehicle dynamic motions affect vehicle dynamic performance attributes such as straight-line stability or handling characteristics. To improve these dynamic performances, understanding the detailed mechanisms by which unsteady aerodynamic loads are caused during dynamic motions and the effects of unsteady aerodynamic loads on vehicle dynamic performance are needed. This paper describes the numerical study of unsteady aerodynamics of a 1/4 scale car model in dynamic pitching motion to clarify the detailed mechanisms by which unsteady aerodynamic loads are caused during the motion. Vortical structures around front wheelhouse and front under side of the body are analyzed by introducing schematic views to understand the mechanisms of unsteady flow fields. Furthermore, effects of aerodynamic devices devised based on the analyses on unsteady aerodynamics are discussed.
Viewing 1 to 30 of 445

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