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Viewing 1 to 30 of 459
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
2017-01-1239
Naoya Take, Takuya Kadoguchi, Masao Noguchi, Kimihiro 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
2017-01-1408
Satoshi Kozai, Yoshihiko Takahashi, Akihiro Kida, Takayuki Hiromitsu, Shinji Kitaura, Sadamasa Sawada, Gladys Acervo, Marius Ichim
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
2017-01-1109
Keisuke Ota, Masami Kondo, Shuntaro Shinohara, Norihiro Tsukamoto, Seiji Masunaga, Ayumu Sagawa
To meet increasing driveability expectation of passenger cars, and stringent fuel economy regulations reducing emitted CO2; Toyota developed new 8-speed automatic transmission "UA80". "UA80" known as “Direct Shift-8AT” is first stepped automatic transmission model based on TNGA philosophy. The new Highlander and Sienna received Direct Shift-8AT. Direct Shift-8AT has an innovative control method with gear train and torque converter models, and provides enhanced driveability and fuel economy performance through high efficiency transmission technology. This paper describes details of new technology and vehicle performance.
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
2017-01-0188
Yoichiro Higuchi, Hiroyuki Kobayashi, Zhiwei Shan, Mikiharu Kuwahara, Yoshiharu Endo, Yuha Nakajima
As vehicle emission regulations become increasingly rigorous, the automotive industry is accelerating the development of electrified vehicle platforms such as Battery Electric Vehicles (BEV) and Plug-in Hybrid Electric Vehicles (PHEV). Since the available waste heat from these vehicles is limited, additional heat sources such as electric heaters are needed for cabin heating operation. However, using electric heaters for winter heating may consume more than 50% of vehicle’s total energy usage which results in less available energy for driving and significant reduction of the driving range of electric vehicles. Use of a heat pump is a solution to improve EV driving range at cold ambient. However prior-art heat pump systems still need the assistance of electric heaters at very cold ambient conditions and for dehumidification operations, which increases system cost and reduces the benefits of heat pump systems.
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
2017-01-1632
Norihiro Tsukamoto, Tomohiro Chimbe, Tomohiro Asami, Keisuke Ota, Seiji Masunaga
A new shift control system using a model-based control method for stepped automatic transmissions. Using a gear train numerical formula model, the model-based shift control system is constructed using minimum calibration parameters with feedforward and feedback controllers. It also adopts control target values for the input shaft revolution and output shaft torque, thus enabling precise control that provides the most suitable shift feeling in various driving situations and for various vehicle characteristics. Furthermore, the model-based shift control system improves robustness in terms of disturbance elements such as production tolerance, time degradation, and use environment. Toyota has adopted this model-based shift control system in its UA80/UB80 8-speed automatic transmissions for front-wheel-drive vehicles and its AGA0 10-speed automatic transmission for rear-wheel-drive vehicles. This paper describes the details of this model-based shift control system.
2017-03-28
Journal Article
2017-01-1278
Keisuke Isomura
Abstract In the automobile industry, interest in the prevention of global warming has always been high. The development of eco cars (HV, EV etc.), aimed at reducing CO2 emissions during operation, has been progressing. In the announcement of its "Toyota Environmental Challenge 2050", Toyota declared its commitment to creating a future in which people, cars, and nature coexist in harmony. In this declaration, Toyota committed to reducing CO2 emissions not only during operation but also over the entire life cycle of vehicles, and to using resources effectively based on a 4 R’s approach (refuse, reduce, reuse, and recycle). Although eco cars decrease CO2 emissions during operation, most of them increase CO2 emissions during manufacturing. For example, the rare-earths (Nd, Dy etc.) used in the magnets of driving motors are extracted through processes that produce a significant amount of CO2 emissions.
2017-03-28
Journal Article
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
Journal Article
2017-01-1156
Koichi Okuda, Yuji Yasuda, Masatoshi Adachi, Atsushi Tabata, Haruhisa Suzuki, Kiyonori Takagi, Tomoo Atarashi, Ryuta Horie
Toyota Motor Corporation developed the Multi Stage Hybrid System for the Lexus flagship LC500h coupe with the aim of achieving an excellent balance between fuel economy and acceleration performance. The Multi Stage Hybrid Transmission used in this new hybrid system includes a shift device located immediately after the power split device and motor. Compared with previous hybrid systems, acceleration performance is improved by increasing the driving force at low and medium vehicle speeds in lower gears, fuel economy and heat management performance are improved by reducing electrical loss by selecting the optimal gear depending on the driving state. The Multi Stage Hybrid Transmission uses a shift device with a wide gear ratio range to maximize both fuel economy and acceleration performance. The transmission was designed to achieve the appropriate size to be mounted in a new platform, as well as class-leading low noise levels for adoption in luxury vehicles.
2017-03-28
Technical Paper
2017-01-1098
Tatsuya Imamura, Atsushi Tabata, Tooru Matsubara, Yuji Iwase, Kenta Kumazaki, Keita Imai
Abstract Lexus developed the Multi Stage Hybrid Transmission for the flagship Lexus LC500h coupe with the aim of achieving an excellent balance between fuel economy and acceleration performance. To gain these benefits, this transmission utilizes a multi-stage approach with the input split mode as an enabler for a concept of multiple high- efficiency points. In order to apply this approach to the transmission, a shift device was located immediately after a power split device. For functioning of the input split mode electrically-controlled continuously variable transmission, the power split device is connected with the motor, generator, and inverters. The optimal gear selection of the shift device to reduce the power loss in accordance with the driving state improves not only fuel economy but also heat management performance compared with the previous hybrid transmission.
2017-03-28
Technical Paper
2017-01-1150
Kenta Kumazaki, Tooru Matsubara, Nobufusa Kobayashi, Shunya Kato, Kazuyuki Shiiba, Ikuo Ando, Hiromichi Kimura, Hiroatsu Endo
Abstract Toyota Motor Corporation developed a new hybrid system, Multi Stage Hybrid System, for the Lexus flagship coupe LC500h with the aim of achieving an excellent balance between fuel economy and acceleration performance. The Multi Stage Hybrid Transmission used in this new hybrid system includes a shift device located immediately after the power split device and motor. Compared with previous hybrid systems, the new hybrid system improves fuel economy by reducing electrical loss in the optimal gears, which are selected depending on the driving state. The system also improves acceleration performance by increasing the driving force at low and medium vehicle speeds in lower gears. In addition, the range of the power split device that cooperates with the shift device was widened to enable both an electrically-controlled continuously variable transmission mode and a ten-speed transmission mode, which creates a direct shift feeling to improve driving pleasure.
2017-03-28
Technical Paper
2017-01-1151
Yosuke Suzuki, Akiko Nishimine, Shinichi Baba, Kenji Miyasaka, Michitaka Tsuchida, Hiroatsu Endo, Norihiro Yamamura, Tomoyuki Miyazaki
Abstract To help respond to growing customer demand for environmentally friendly vehicles, a new transaxle for plug-in hybrid vehicles (PHVs) has been developed that achieves excellent fuel economy and ensures high performance when the PHV operates in electric vehicle (EV) mode. Under the basic concept of sharing a large number of parts with the transaxle in the all new Prius, the newly designed PHV transaxle was developed with the aim of enhancing EV power and range. To achieve our goal, the new transaxle uses a Dual Motor Drive System that operates the generator as a motor to supplement the existing motor. It also features an electrical oil pump (EOP) that improves cooling performance in EV mode. The developed transaxle helps to advance the PHV as a key next-generation environmentally friendly vehicle by maximizing the performance of the Toyota Hybrid System (THS) and achieving even better dynamic EV mode performance than the new Prius HV.
2017-03-28
Technical Paper
2017-01-1130
Shinya Takamatsu, Nobuharu Imai, Koji Tsurumura, Seiji Yamashita, Hiroaki Tashiro
Abstract The renewed platform of the upcoming flagship front-engine, rear-wheel drive (FR) vehicles demands high levels of driving performance, fuel efficiency and noise-vibration performance. The newly developed driveline system must balance these conflicting performance attributes by adopting new technologies. This article focuses on several technologies that were needed in order to meet the demand for noise-vibration performance and fuel efficiency. For noise-vibration performance, this article will focus on propeller shaft low frequency noise (booming noise). This noise level is determined by the propeller shaft’s excitation force and the sensitivity of differential mounting system. In regards to the propeller shaft’s excitation force, the contribution of the axial excitation force was clarified. This excitation force was decreased by adopting a double offset joint (DOJ) as the propeller shaft’s second joint and low stiffness rubber couplings as the first and third joints.
2017-03-28
Technical Paper
2017-01-0917
Go Hayashita, Motoki Ohtani, Keiichiro Aoki, Shuntaro Okazaki
Trying to prevent global warming and air pollution, Toyota has led the world in the field of after treatment technologies including the three-way catalyst (TWC) system with oxygen sensor. In this study, a new emission control system for Toyota New Global Architecture (TNGA) Engine which brings lower fuel consumption and higher performance for creating ever-better cars is reported. The new system was adopted the exhaust cooling system and small capacity TWC. These can achieve a balance between heating TWC for early activation and cooling TWC for protection. As a result, regardless of the platform or the unit type of the vehicle, it is possible to unify the catalyst temperature which is a key parameter in the exhaust gas purification. In order to reduce emission also with the small capacity TWC, it is necessary to a high accuracy air-fuel ratio (A/F) control.
2017-03-28
Technical Paper
2017-01-1178
Ken Laberteaux, Karim Hamza
This work presents a simulation-based modeling of the equivalent greenhouse gas (GHG) of plugin hybrid electric vehicles (PHEVs) for real driving patterns obtained from monitoring of real vehicles in public survey data sets such as the California Household Travel Survey (CHTS). Aim of the work is to highlight the difference in attainable GHG reduction by adopting a PHEV instead of a conventional vehicle (CV), for different driving patterns by various sub-populations of vehicles. Modeling of the equivalent GHG for a trip made by a PHEV can be challenging since it not only depends on the speed trace of the trip in question and vehicle energy efficiency, but also on: i) battery range of the PHEV, ii) GHG equivalent of the electricity used to charge the battery, as well as iii) battery depletion in previous trips since the last charging event.
2017-03-28
Technical Paper
2017-01-1162
Ken Laberteaux, Karim Hamza
Electric drive vehicles (EDV) have the potential to greatly reduce greenhouse gas (GHG) emissions and thus, there are many policies in place to encourage the purchase and use of gasoline-hybrid, battery, plug-in hybrid, and fuel cell electric vehicles. But not all vehicles are the same, and households use vehicles in very different ways. What if policies took these differences into consideration with the goal of further reducing GHG emissions? This paper attempts to answer two questions: i) are there certain households that, by switching from a conventional vehicle to an EDV, would result in a comparatively large GHG reduction (as compared to other households making that switch), and, if so, ii) how large is the difference in GHG reductions? The paper considers over 65,000 actual GPS speed traces (generated by approximately 2,900 monitored vehicles) collected by the 2013 California Household Travel Survey (CHTS).
2017-03-28
Technical Paper
2017-01-1398
Yoshiyuki Hatakeyema
Abstract Since drowsy driving is a major cause of serious traffic accidents, there is a growing requirement for drowsiness prevention technologies. This study proposes a drowsy driving prediction method based on eye opening time. One issue of using eye opening time is predicting strong drowsiness before the driver actually feels sleepy. Because overlooking potential hazards is one of the causes of traffic accidents and is closely related to driver cognition and drowsiness, this study focuses on eye opening movements during driving. First, this report describes hypotheses concerning drowsiness and eye opening time based on the results of previous studies. It is assumed that the standard deviation of eye opening time (SDEOP) indicates driver drowsiness and the following two transitions are considered: increasing and decreasing SDEOP. To confirm the hypotheses, the relationship between drowsiness and SDEOP was investigated.
2017-03-28
Journal Article
2017-01-1179
Tatsuya Arai, Ozaki Takashi, Kazuki Amemiya, Tsuyoshi Takahashi
Abstract Polymer electrolyte membrane fuel cell (PEFC) systems for fuel cell vehicles (FCVs) require both performance and durability. Carbon is the typical support material used for PEFC catalysts. However, hydrogen starvation at the anode causes high electrode potential states (e.g., 1.3 V with respect to the reversible hydrogen electrode) that result in severe carbon support corrosion. Serious damage to the carbon support due to hydrogen starvation can lead to irreversible performance loss in PEFC systems. To avoid such high electrode potentials, FCV PEFC systems often utilize cell voltage monitor systems (CVMs) that are expensive to use and install. Simplifying PEFC systems by removing these CVMs would help reduce costs, which is a vital part of popularizing FCVs. However, one precondition for removing CVMs is the adoption of a durable support material to replace carbon.
2017-03-28
Technical Paper
2017-01-0589
Shigeru Itabashi, Eiji Murase, Hiroya Tanaka, Masaaki Yamaguchi, Tomokazu Muraguchi
Abstract Toyota Motor Corporation has developed a new series of engines under the Toyota New Global Architecture (TNGA) design philosophy, which aims to satisfy customer requirements for both fun-to-drive dynamic performance and better fuel economy by adopting a high-speed combustion concept to improve thermal efficiency and specific power. This new engine series achieves a maximum engine thermal efficiency of 40%, a specific power ratio of 60 kW/l, and lower emissions by combining high-speed combustion and a high compression ratio with a high-tumble intake port, high-energy ignition coil, high-pressure multi-hole nozzle direct injector, and new electrical variable valve timing (VVT). The first engine in this series is a new 4-cylinder 2.5-liter gasoline naturally aspirated engine for use in passenger cars alongside a new TNGA 8-speed automatic transmission, which was introduced for minivans and SUVs in the U.S. market in 2016.
2017-03-28
Journal Article
2017-01-1539
Vinh Long Phan, Hiroshi Tanaka, Takaaki Nagatani, Mikio Wakamatsu, Tsuyoshi Yasuki
Abstract High frequency wind noise caused by turbulent flow around the front pillars of a vehicle is an important factor for customer perception of ride comfort. In order to reduce undesirable interior wind noise 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. Using the well-known Curle’s equation, ENP can be represented as a surface integral of an acoustic intensity distribution, referred to as Exterior Noise Power Distribution (ENPD). ENPD is estimated from turbulent surface pressure fluctuation and mean convective velocity in the vicinity of the vehicle surface.
2017-03-28
Journal Article
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
Journal Article
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
Journal Article
2017-01-1328
Yoshiteru Tanaka, Jun Yamamura, Atsushi Murakawa, Hiroshi Tanaka, Tsuyoshi Yasuki
Abstract When vehicles run on the flooded road, water enters to the engine compartment and sometimes reaches the position of the air intake duct and electrical parts and causes the reliability problems. Numerical simulation is an effective tool for this phenomenon because it can not only evaluate the water level before experiment but also identify the intrusion route. Recently, the gap around the engine cooling modules tends to become smaller and the undercover tends to become bigger than before in order to enhance the vehicle performance (e.g., aerodynamics, exterior noise). Leakage tightness around the engine compartment becomes higher and causes an increase of the buoyancy force from the water. Therefore the vehicle attitude change is causing a greater impact on the water level. This paper describes the development of a water level prediction method in engine compartment while running on the flooded road by using the coupled multibody and fluid dynamics.
2017-03-28
Technical Paper
2017-01-1188
Daisuke Hayashi, Atsushi Ida, Shota Magome, Takahisa Suzuki, Satoshi Yamaguchi, Ryosuke Hori
Abstract The key challenge in designing a high power density fuel cell is to reduce oxygen transport loss due to liquid water. However, liquid water transport from catalyst layers to channels under operating conditions is not completely understood. Toyota developed a high resolution space and time liquid water visualization technique using synchrotron x-ray (Spring-8) radiography. In addition, a simulation method was created based on computational fluid dynamics (CFD) to identify the cell performance relationship to water distribution. The relationship among gas diffusion layer (GDL) parameters, water distribution, and fuel cell performance was clarified by combining the techniques Toyota developed.
2017-03-28
Technical Paper
2017-01-1189
Tsuyoshi Maruo, Masashi Toida, Tomohiro Ogawa, Yuji Ishikawa, Hiroyuki Imanishi, Nada Mitsuhiro, Yoshihiro Ikogi
Abstract Toyota Motor Corporation (TMC) has been developing fuel cell vehicles (FCVs) since 1992. As part of a demonstration program, TMC launched the FCHV-adv in 2008, which established major technical improvements in key performance areas such as efficiency, driving range, durability, and operation in sub-zero conditions. However, to encourage commercialization and widespread adoption of FCVs, further improvements in performance were required. During sub-zero operating conditions, the FC system output power was lower than under normal operating conditions. The FC stack in the FCHV-adv needed to dry the electrolyte membrane to remove unneeded water from the stack. This increased the stack resistance and caused low output power. In December 2014, TMC launched the world’s first commercially available FCV named the Mirai, which greatly improved output power even after start-up in sub-zero conditions.
2017-03-28
Journal Article
2017-01-1163
Shinji Ichikawa, Hiroaki Takeuchi, Shigeru Fukuda, Shigeki Kinomura, Yoshiki Tomita, Yosuke Suzuki, Takahiko Hirasawa
Abstract A next-generation plug-in hybrid system has been developed for the new Prius Prime. The objective of this development was to maximize the performance of the Toyota Hybrid System II (THS II) developed for the new fourth generation Prius HV, while achieving even better dynamic performance in electric vehicle (EV) mode. These objectives were accomplished by the adoption of new components and systems, as well as refinements to existing hybrid vehicle (HV) components. This paper describes the development of this new plug-in hybrid system.
2017-03-28
Journal Article
2017-01-1173
Shunya Kato, Ikuo Ando, Koji Ohshima, Tooru Matsubara, Yasuhiro Hiasa, Hideki Furuta, Yuma Mori
Abstract Lexus launched the new hybrid luxury coupe LC500h in 2017 to help enhance its brand image and competitiveness for the new generation of Lexus. During the development of the LC500h, major improvements were made to the hybrid system by adopting the newly-developed Multi Stage Hybrid System, which combines a multi stage shift device with the transmission from the previous hybrid system to maximize the potential of the electrically-controlled continuously variable transmission. Optimum engine and electrical component specifications were designed for the new vehicle and transmission. As a result, the LC500h achieves a 0-to-60 mph acceleration time of 4.7 seconds, with a combined fuel economy of 30.0 mpg while satisfying SULEV emissions requirements. Two controls were constructed to help resolve the issues that arose due to adding the shift device.
2017-03-28
Journal Article
2017-01-1244
Keisuke Kimura, Tasbir Rahman, Tadashi Misumi, Takeshi Fukami, Masafumi Hara, Sachiko Kawaji, Satoru Machida
A new IGBT has been developed for Toyota’s 4th generation HV’s. The power loss reduction of power control units (PCUs) for hybrid vehicles (HVs) is essential to improve their fuel efficiency. It is important to reduce the loss of the power devices (IGBTs and FWDs) used in the PCUs, because of being about 20% of the whole power loss of the HVs. Also the trade-off between the power device downsizing and the heat dissipation feasibility is the important technical issues. In order to achieve the 4th generation PCU design goal, the IGBT development goal is to improve 19.8% of the losses, 30% of downsizing, 14% of the breakdown-voltage than the previous generation. For the loss reduction goal, SBL (Super-Body-Layer) structure is installed to improve the trade-off characteristic between the switching loss and the steady-state loss. The goal is achieved by optimizing the SBL impurity concentration which is an important parameter for trade-off characteristic improvement.
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