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Viewing 1 to 30 of 423
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.
2016-10-17
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
One effective and easy way to improve fuel economy for automobiles is to decrease viscosity of lubricants, as it brings less churning loss. However, this option creates a higher potential for thinner oil film, which could damage the mechanical parts. This paper describes a new low-viscosity gear oil technology which was successfully developed to improve wear at tapered-roller bearings in differential gear units, whereas achieving higher fuel economy performance. As for tapered-roller bearings in differential gear units protected by gear oils, one major damage is supposed to cause wear at large end face of rollers and the counterpart, so-called bearing bottom wear. In order to understand the wear mechanism, wear at rolling contact surface of rollers and the counterparts, so-called bearing side wear was additionally observed to confirm the wear impact on tapered-roller bearing.
2016-10-17
Technical Paper
2016-01-2198
Chikara Dodate, Sachio Mori, Masato Kawauchi, Rio Shimizu
In recent years, a lot of direct-injection gasoline engines are developed due to the high rated power, low end torque and fuel efficiency because of increased volumetric efficiency and reduced knocking. On the other hand, the measure for particular matters (PM) and the oil dilution become important. Therefore it is necessary to identify a spray behavior in cylinder with the combination of flow to design a direct injector. To identify the spray behavior, a CFD analysis has been utilized. However, before it was necessary to fit spray model constants and parameters based on measurement results including a penetration and SMD. Especially, in the case of the nozzle whose sectional area of exit is larger than that of inlet like a fan-shape spray nozzle, the fitting process is complicated, because of an inhomogeneity internal flow. In this study, new simulation method of spray is developed.
2016-10-17
Technical Paper
2016-01-2353
Kazunori Harima, Shinji Tsuchiya, Takuro Morino, Yuji Nagasawa
CVT belts are constructed with multiple elements and layered rings, and friction loss occurs between each parts. Due to belt geometry, a large belt friction loss occurs between the elements and the inner most ring. Therefore, to improve efficiency, it is effective to decrease the slip between the elements and the inner most ring. So, the torque transmitted is influenced by the slip between the elements and the inner most ring. When the slip is decreased, it is thought that the amount of torque transmitted by the ring change. For efficiency improvement, it is necessary to analyze the change of the torque transmitted by the ring due to the decrease of slip between the elements and the inner most ring, but to verify of the internal thrust force in the real load state is difficult because it is a phenomenon inside the belt.
2016-04-05
Technical Paper
2016-01-0973
Takafumi Yamauchi, Yoshiki Takatori, Koichiro Fukuda, Masatoshi Maruyama
Abstract Urea-SCR (Selective Catalytic Reduction) systems are getting a lot of attention as the most promising NOx reduction technology for heavy-duty diesel engine exhaust. In order to promote an effective development for an optimal urea-SCR after-treatment system, it is important to clarify the decomposition behavior of the injected urea and a detailed reaction chemistry of the reactants on the catalyst surface in exhaust gases. In this paper we discuss experimental and numerical studies for the development of a numerical simulation model for the urea-SCR catalyst converter. As a first step, in order to clarify the behavior of reductants in an urea-SCR converter, two types of diagnostic technique were developed; one is for measuring the amount of NH3, and the other is for measuring the amount of total reductants including unreacted urea and iso-cyanic acid. These techniques were applied to examine the behavior of reductants at the inlet and inside the SCR converter.
2016-04-05
Technical Paper
2016-01-0960
Arifumi Matsumoto, Kenji Furui, Makoto Ogiso, Toru Kidokoro
Abstract Urea selective catalytic reduction (SCR) systems are a promising technology for helping to lower NOx emissions from diesel engines. These systems also require on-board diagnostic (OBD) systems to detect malfunctioning catalysts. Conventional OBD methodology for a SCR catalyst involves the measurement of NOx concentration downstream of the catalyst. However, considering future OBD regulations, erroneous diagnostics may occur due to variations in the actual environment. Therefore, to enhance OBD accuracy, a new methodology was examined that utilizes NH3 slip as a new diagnostic parameter in addition to NOx. NH3 slip increases as the NOx reduction performance degrades, because both phenomena are based on deterioration in the capability of the SCR catalyst to adsorb NH3. Furthermore, NH3 can be measured by existing NOx sensors because NH3 is oxidized to NO internally. To make use of NH3 slip, an estimation model was developed.
2016-04-05
Technical Paper
2016-01-1363
Nobuhiro Ide, Jun Hioki, Hiroki Okada
Abstract Because of its convenience, electronic key systems are adopted by many automakers. Ensuring the performance of low frequency (LF) and ultra-high frequency (UHF) electromagnetic waves is a critical part of system development. One of the most important performance aspects of this system is ensuring communication in the required area, and the tuning process is a key factor in the development phase. Conventionally, a large amount of work hours and cost is required for this tuning process, which usually adopts a cut-and-try approach based on technical experience to satisfy the required specifications in the LF band. The development process was successfully shortened by applying the newly developed LF electromagnetic simulation technique described in this paper.
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
2016-01-1458
Ryuta Ono, Wataru Ike, Yuki Fukaya
Abstract Toyota Safety Sense is a safety system package developed to help drivers avoid accident types with a high frequency of occurrence. This paper deals with pre-collision system which forms the core of Toyota Safety Sense, especially Toyota Safety Sense P which uses a combined sensor configuration consisting of a monocular camera paired with millimeter wave radar, in order to achieve both high recognition performance and reliability. The use of a wide-angle monocular camera, millimeter wave radar integrated in the front grill emblem, and a collision determination algorithm for pedestrian targets enabled the development of a pre-collision system comprising detection capability of crossing pedestrians. Toyota has developed warning and pre-collision brake assist for driver to assist in avoiding a collision effectively; In addition, Pre-collision brake has achieved high level of performance for the drivers who cannot avoid a collision.
2016-04-05
Technical Paper
2016-01-1420
Shinichi Kojima, Shigeyoshi Hiratsuka, Nobuyuki Shiraki, Kazunori Higuchi, Toshihiko Tsukada, Keiichi Shimaoka, Kazuya Asaoka, Sho Masuda, Kazuhiko Nakashima
Abstract This study aims at the development of a projection pattern that is capable of shortening the time required by a driver to perceive a pedestrian at night when a vehicle’s high beams are utilized. Our approach is based on the spatio-temporal frequency characteristics of human vision. Visual contrast sensitivity is dependent on spatiotemporal frequency, and maximum contrast sensitivity frequency varies depending on environmental luminance. Conventionally, there are several applications that utilize the spatio-temporal frequency characteristics of human vision. For example, the National Television System Committee (NTSC) television format takes into consideration low-sensitivity visual characteristics. In contrast, our approach utilizes high-sensitivity visual characteristics based on the assumption that the higher contrast sensitivity of spatio-temporal frequencies will correlate more effectively with shorter perception times.
2016-04-05
Technical Paper
2016-01-1412
Takeshi Hamaguchi, Satoshi Inoue, Shigeyuki Kimura, Terumasa Endo
Abstract In driver-focused vehicle development, driver workload is generally evaluated subjectively, with physiological, psychological, and behavioral indexes used to quantify and substantiate the subjective rating. In contrast, a model of driver behavior expresses the driver’s behavioral characteristics which make it possible to estimate how the driver will incorporate information into vehicle operation. Therefore, it is presumed to be capable of estimating the internal state of a driver. Conventionally, a model of driver behavior related to pedal operation has been used for evaluating the driver’s habits and the acceptability of various types of support devices. However, it has not been used for estimating driver workload related to pedal operation. To examine driver workload, this study divided pedal operation magnitude into two components: a learning/judgment component and a correcting component for prediction errors. A method was devised of separating these two components.
2016-04-05
Technical Paper
2016-01-1452
Eiichiro Murata, Tasuku Usui, Kazunori Nogi, Hiroyuki Takahashi
Abstract In order to help avoid or mitigate rear-end collisions a Pre-Collision System (PCS) was developed. The purpose of this study is to clarify the Time-to-Collision (TTC) distribution when approaching a lead vehicle under normal driving condition. To enhance the effectiveness of PCS, warnings and/or automatic brake activation should happen as early as possible, however, if too early there is a high possibility of false warnings or activations, which is not desirable. If the distribution of distance to a lead vehicle under normal driving conditions is quantified, an approach limit can be estimated. In this study, we try to clarify a TTC distribution that is approximated by a log-normal distribution. Then, we investigate the Enhanced Time-to-Collision (ETTC) that is the secondary predictive value of TTC. And, we clarify the log-normal distribution of ETTC is a more stable approximator of normal driving than a log-normal distribution of TTC.
2016-04-05
Technical Paper
2016-01-1454
Libo Dong, Stanley Chien, Jiang-Yu Zheng, Yaobin Chen, Rini Sherony, Hiroyuki Takahashi
Abstract Pedestrian Automatic Emergency Braking (PAEB) for helping avoiding/mitigating pedestrian crashes has been equipped on some passenger vehicles. Since approximately 70% pedestrian crashes occur in dark conditions, one of the important components in the PAEB evaluation is the development of standard testing at night. The test facility should include representative low-illuminance environment to enable the examination of the sensing and control functions of different PAEB systems. The goal of this research is to characterize and model light source distributions and variations in the low-illuminance environment and determine possible ways to reconstruct such an environment for PAEB evaluation. This paper describes a general method to collect light sources and illuminance information by processing large amount of potential collision locations at night from naturalistic driving video data.
2016-04-05
Technical Paper
2016-01-1447
Qiang Yi, Stanley Chien, Jason Brink, Wensen Niu, Lingxi Li, Yaobin Chen, Chi-Chen Chen, Rini Sherony, Hiroyuki Takahashi
Abstract As part of active safety systems for reducing bicyclist fatalities and injuries, Bicyclist Pre-Collision System (BPCS), also known as Bicyclist Autonomous Emergency Braking System, is being studied currently by several vehicles manufactures. This paper describes the development of a surrogate bicyclist which includes a surrogate bicycle and a surrogate bicycle rider to support the development and evaluation of BPCS. The surrogate bicycle is designed to represent the visual and radar characteristics of real bicyclists in the United States. The size of bicycle surrogate mimics the 26 inch adult bicycle, which is the most popular adult bicycle sold in the US. The radar cross section (RCS) of the surrogate bicycle is designed based on RCS measurement of the real adult sized bicycles.
2016-04-05
Technical Paper
2016-01-1319
Kimitoshi Tsuji, Katsuhiko Yamamoto
Abstract It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration using virtual engine specifications and a virtual vehicle frame. In our former study, we showed the 1D physical power plant model with electrical starter, battery that can predict combustion transient torque, combustion heat energy and fuel efficiency. The simulation result agreed with measured data. For idling stop system, the noise and vibration during start up is important factor for salability of the vehicle. In this paper, as an application of the 1D physical power plant model (engine model), we will show the result of analysis that is starter shaft resonance and the effect on the engine mount vibration of restarting from idle stop. First, an engine model for 3.5L 6cyl NA engine was developed by energy-based model using VHDL-AMS. Here, VHDL-AMS is modeling language registered in IEC international standard (IEC61691-6) to realize multi physics on 1D simulation.
2016-04-05
Technical Paper
2016-01-0740
Kazuhisa Inagaki, Jyunichi Mizuta, Kiyomi Kawamura, Yoshinori Idota, Takeshi Hashizume
Abstract 1 Recently, demand for small-bore compact vehicle engines has been increasing from the standpoint of further reducing CO2 emissions. The generalization and formulation of combustion processes, including those related to emissions formation, based on a certain similarity of physical phenomena regardless of engine size, would be extremely beneficial for the unification of development processes for various sizes of engines. The objective of this 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.
2016-04-05
Technical Paper
2016-01-1287
Kazutaka Kimura, Yuki Kudo, Akinori Sato
Abstract In recent years, automakers have been developing various types of environmentally friendly vehicles such as hybrid (HV), plug-in hybrid (PHV), electric (EV), and fuel cell (FCV) vehicles to help reduce greenhouse gas (GHG) emissions. However, there are few commercial solar vehicles on the market. One of the reasons why automakers have not focused attention on this area is because the benefits of installing solar modules on vehicles under real conditions are unclear. There are two difficulties in measuring the benefits of installing solar modules on vehicles: (1) vehicles travel under various conditions of sunlight exposure and (2) sunlight exposure conditions differ in each region. To address these problems, an analysis was performed based on an internet survey of 5,000 people and publically available meteorological data from 48 observation stations in Japan.
2016-04-05
Technical Paper
2016-01-1286
Takuya Hara, Takahiro Shiga, Kazutaka Kimura, Akinori Sato
Abstract Introducing effective technologies to reduce carbon emissions in the transport sector is a critical issue for automotive manufacturers to contribute to sustainable development. Unlike the plug-in electric vehicles (PEVs), whose effectiveness is dependent on the carbon intensity of grid electricity, the solar hybrid vehicle (SHV) can be an alternative electric vehicle because of its off-grid, zero-emission electric technology. Its usability is also advantageous because it does not require manual charging by the users. This study aims at evaluating the economic, environmental, and usability benefits of SHV by comparing it with other types of vehicles including PEVs. By setting cost and energy efficiency on the basis of the assumed technology level in 2030, annual cost and annual CO2 emissions of each vehicle are calculated using the daily mileage pattern obtained from a user survey of 5,000 people in Japan and the daily radiation data for each corresponding user.
2016-04-05
Technical Paper
2016-01-1187
Nobuaki Mizutani, Kazunobu Ishibashi
Abstract While carbon supported PtCo alloy nanoparticles emerged recently as the new standard catalyst for oxygen reduction reaction in polymer membrane electrolyte fuel cells, further improvement of catalyst performance is still of great importance to its application in fuel cell vehicles. Herein, we report two examples of such efforts, related to the improvements of catalyst preparation and carbon support design, respectively. First, by lowering acid treatment voltage, the effectiveness for the removal of unalloyed Co was enhanced significantly, leading to less Co dissolution during cell operation and about 40% higher catalyst mass activity. It has been also found that the use of nonporous carbon support material promoted mass transfer and resulted in substantial drop of overpotential at high current and low humidity. This result may suggest an effective strategy towards the development of fuel cell systems that operate without additional humidification.
2016-04-05
Technical Paper
2016-01-1230
Takaoki Ogawa, Atsushi Tanida, Toshifumi Yamakawa, Masaki Okamura
Abstract A prototype power control unit (PCU) was manufactured using silicon carbide (SiC) power semiconductors (diodes and transistors), which have low power loss when switching on and off. This PCU was installed in a hybrid vehicle (HV) and driven on a test course and chassis dynamometer. The test results confirmed a fuel efficiency improvement of about 5 percent.
2016-04-05
Technical Paper
2016-01-1093
Takao Ohki, Tomoyasu Wada, Tomoyuki Kano, Tomoyoshi Ishimaru, Hideya Osawa
Abstract In recent years, awareness of environmental problems has increased on a global scale, and the development of low fuel consumption technologies has become more and more important in commercial vehicles, as it has been in passenger vehicles. A new 6-speed manual transmission was developed with direct-drive double-overdrive to contribute to the fuel economy performance and engine power of commercial vehicles through gear ratio optimization.
2016-04-05
Technical Paper
2016-01-1097
Satoshi Fukuyama, Tomohide Suzuki, Akira Murata, Hiroshi Mizoguchi, Toshihiko Kamiya
Abstract Aisin AW (AW) and Toyota Motor Corporation (TMC) have developed a new RWD 6 speed automatic transmission, AWR6B45(AC60), suitable for SUV’s and LDT’s in the worldwide market, not only for North America but also for other countries including emerging nations. This 6 speed automatic transmission has achieved low cost, equivalent to AW and TMCs’ current 5 speed automatic transmission, while realizing improvement in both fuel economy and driving performance against current in-house 5-speed automatic transmissions, in addition to satisfying both toughness against various usage and light weight/compactness. They are accomplished by using a compact gear train structure, the latest efficiency improvement technologies, and a high-response, compact hydraulic control system. In addition, the compactness of this 6 speed automatic transmission enables it to replace current 4 speed and 5 speed automatic transmissions for various engine applications.
2016-04-05
Technical Paper
2016-01-1135
Yoshitaka Shinoda, Atsushi Mori, Takeo Yamamoto, Takeshi Nakamura
Abstract Driveshafts are composed of a transmission side joint, wheel side joint, and shaft which connect the two joints. The Rzeppa type constant velocity joint (CVJ) is usually selected as the wheel side joint of a drive shaft for front wheel drive automobiles. Due to recent needs of fuel efficiency and lighter weight for vehicles, it is necessary to reduce the joint size and improve the efficiency of a CVJ. In order to reduce the weight, solving tribology details for long life under high contact pressure is an important issue for developing a CVJ. It is difficult to understand the characteristics of a contact surface, such as relative slip velocity or spin behavior, because the outer race, inner race, cage, and balls, act complicatedly and exchange loads at many points. Meanwhile, after joint endurance tests, ball spalling marks at pole of the ball are sometimes observed.
2016-04-05
Technical Paper
2016-01-1155
Toru Nakamura, Takahiro Misawa, Yusuke Futakuchi, Kensuke Kamichi
Abstract Toyota Motor Corporation (TMC) began a wireless charging field test in February 2014. A wireless charging system was installed at the residences of test subjects with the aim of identifying issues related to convenience and installation in daily usage. The test vehicle was fabricated by installing a wireless charging system into a Prius PHV (Plug-in Hybrid Vehicle). The installed system had the same charging power as the cable charging system used on the base vehicle, and had a charging time of 1.5 hours. A high-frequency 85 kHz power supply and primary coil were produced for the charging infrastructure. To identify differences in charging behavior, the test subjects were asked to use the cable charging system for the first month before changing to the wireless charging system for two months. Data acquisition was performed by an on-board data logger and through interviews with the test subjects.
2016-04-05
Technical Paper
2016-01-1355
Jeffrey R. Hodgkins, Walter Brophy, Thomas Gaydosh, Norimasa Kobayashi, Hiroo Yamaoka
Abstract Current vehicle acoustic performance prediction methods, CAE (computer aided engineering) or physical testing, have some difficulty predicting interior sound in the mid-frequency range (300 to 1000 Hz). It is in this frequency range where the overall acoustic performance becomes sensitive to not only the contributions of structure-borne sources, which can be studied using traditional finite element analysis (FEA) methods, but also the contribution of airborne noise sources which increase proportional to frequency. It is in this higher frequency range (>1000 Hz) that physical testing and statistical CAE methods are traditionally used for performance studies. This paper will discuss a study that was undertaken to test the capability of a finite element modeling method that can accurately simulate air-borne noise phenomena in the mid-frequency range.
2016-04-05
Technical Paper
2016-01-1521
Masaaki Kuwahara, Tsuyoshi Yasuki, Takeki Tanoue, Ryosuke Chikazawa
Abstract This paper describes impact kinematics and injury values of Hybrid III AM50, THOR AM50 and THUMS AM50 in simulated oblique frontal impact conditions. A comparison was made among them in driver and passenger seat positions of a midsize sedan car finite element (FE) model. The simulation results indicated that the impact kinematics of THOR was close to that of THUMS compared to that of the Hybrid III. Both THOR and THUMS showed z-axis rotation of the rib cage, while Hybrid III did not. It was considered that the rib cage rotation was due primarily to the oblique impact but was allowed by flexibility of the lumbar spine in THOR and THUMS. Lateral head displacement observed in both THOR and THUMS was mostly induced by that rotation in both driver seat and passenger seat positions. The BrIC, thorax and abdominal injury values were close to each other between THOR and THUMS, while HIC15 and Acetabulum force values were different.
2016-04-05
Technical Paper
2016-01-1266
Shinichi Urabe, Kazutaka Kimura, Yuki Kudo, Akinori Sato
Abstract Solar and other green energy technologies are attracting attention as a means of helping to address global warming caused by CO2 and other emission gases. Countries, factories, and individual homes around the world have already introduced photovoltaic energy power sources, a trend that is likely to increase in the future. Electric vehicles powered from photovoltaic energy systems can help decrease the CO2 emmissions caused by vehicles. Unlike vehicles used for solar car racing, it is not easy to equip conventional vehicles with solar modules because the available area for module installation is very small to maintain cabin space, and the body lines of conventional vehicles are also usually slightly rounded. These factors decrease the performance of photovoltaic energy systems and prevent sufficient electric power generation. This research aimed to estimate the effectiveness of a solar module power generating system equipped on a conventional car, the Toyota Prius PHV.
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
2016-01-1185
Takahiko Hasegawa, Hiroyuki Imanishi, Mitsuhiro Nada, Yoshihiro Ikogi
Abstract Toyota Motor Corporation (TMC) has been developing fuel cell (FC) system technology since 1992. In 2008 the Toyota "FCHV-adv" was released as part of a demonstration program. It established major improvements in key performance areas such as cold start/drive capability, efficiency, driving range, and durability. However, in order to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs), improvements in performance and further reductions in size and cost were required.In December 2014, Toyota launched the world’s first commercially available fuel cell vehicle (FCV) the "Mirai" powered by the Toyota Fuel Cell System (TFCS). Simplicity, reliability and efficiency have been significantly improved within the Toyota TFCS. As a result, the Mirai has become an attractive vehicle which could lead the way towards full-scale popularization of FCVs.
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