Search Results

In the present paper, we introduce a drivetrain system using an electromagnetic coupling for hybrid electric vehicles, and propose a new control concept of vibration torque interception. The electromagnetic coupling is an electric machine that is composed of a pair of rotors, and electromagnetic torque acts mutually between the rotors. In the drivetrain system, the electromagnetic coupling works as a torque transmission device with a rotational-speed-converting function. We demonstrate that, by using this control, the electromagnetic coupling also works as a damping device that intercepts the vibration torque of the internal combustion engine, while transmitting the smooth torque to its drive line. Using a model of a two-inertia resonance system, a control system is designed such that a transfer function representing input-to-output torque is shaped in the frequency domain.

Separate from the event data recorder (EDR), which records and stores data from qualifying vehicle crash events, the Vehicle Control History (VCH) on Toyota vehicles records and stores certain vehicle data based on select driver inputs, such as hard acceleration or braking, or upon the activation of certain vehicle dynamic control systems such as antilock braking system (ABS), traction control (TRAC), vehicle stability control (VSC), and the pre-collision system (PCS). In the United States, VCH was first equipped on the 2013 Toyota RAV4 and has been subsequently introduced into other Toyota and Lexus models. Most recently, in addition to VCH data, additional PCS operational data (PCS-O) and image data (PCS-I) may be recorded and stored. The image storage capability may record under certain conditions such as if the system has automatically applied the vehicle brakes.

Trivalent chromate coating is replacing the conventional hexavalent chromate coating applied on zinc plating. Zinc plating uses one of three types of plating baths (zincate, cyanide and chloride) according to the characteristics required of subject parts. It has been recognized that trivalent chromate coating provides different corrosion resistance depending on the type of zinc plating bath used. Zinc plating with chromate coating were analyzed to clarify the cause of the corrosion resistance variation with the type of zinc plating bath. It has been revealed that the chromate coating thickness and the condition of top SiO2 layer vary with the type of zinc plating bath, resulting in corrosion resistance variation.

This paper presents a design method for continuous fiber composites in three-dimensional space with locally varying orientation distribution and their fabrication method. The design method is formulated based on topology optimization by augmented tensor field design variables. The fabrication method is based on Tailored Fiber Placement technology, whereby a CNC embroidery machine prepares the preform. The fiber path is generated from an optimized orientation distribution field. The preform is formed with vacuum-assisted resin transfer molding. The fabricated prototype weighs 120 g, a 70% weight reduction, achieving 3.5× mass-specific stiffness improvement.

Wireless Power Transfer (WPT) promises automated and highly efficient charging of electric and plug-in-hybrid vehicles. As commercial development proceeds forward, the technical challenges of efficiency, interoperability, interference and safety are a primary focus for this industry. The SAE Vehicle Wireless Power and Alignment Taskforce published the Recommended Practice J2954 to help harmonize the first phase of high-power WPT technology development. SAE J2954 uses a performance-based approach to standardizing WPT by specifying ground and vehicle assembly coils to be used in a test stand (per Z-class) to validate performance, interoperability and safety. The main goal of this SAE J2954 bench testing campaign was to prove interoperability between WPT systems utilizing different coil magnetic topologies. This type of testing had not been done before on such a scale with real automaker and supplier systems.

Automotive control systems such as powertrain control interact with the open physical environment, and from this nature, expensive prototyping is indispensable to capture a deep understanding of the system requirements and to develop the corresponding control software. Model-based development (MBD) has been promoted to improve productivity by virtual prototyping. Even with MBD, systematic validation of the software specification remains as a major challenge and it still depends heavily on individual engineers' skill and knowledge. Though the introduction of graphical software modeling improved the situation, it requires much time to identify the primal functions, so-called “design interests”, from a large complex model where irrelevant components are mixed with, and to validate it properly.

Exhaust gas recirculation (EGR) can be used to mitigate knock in SI engines. However, experiments have shown that the effectiveness of various EGR constituents to suppress knock varies with fuel type and compression ratio (CR). To understand some of the underlying mechanisms by which fuel composition, octane sensitivity (S), and CR affect the knock-mitigation effectiveness of EGR constituents, the current paper presents results from a chemical-kinetics modeling study. The numerical study was conducted with CHEMKIN, imposing experimentally acquired pressure traces on a closed reactor model. Simulated conditions include combinations of three RON-98 (Research Octane Number) fuels with two octane sensitivities and distinctive compositions, three EGR diluents, and two CRs (12:1 and 10:1). The experimental results point to the important role of thermal stratification in the end-gas to smooth peak heat-release rate (HRR) and prevent acoustic noise.

Phosphor thermometry was used during fuel injection in an optical engine with the glass piston of reentrant type. SiO2 coated phosphor particle was used for the gas-phase temperature measurements, which gave much less background signal. The measurements were performed in motored mode, in combustion mode with injection of n-heptane and in non-combustion mode with injection of iso-octane. In the beginning of injection period, the mean temperature of each injection cases was lower than that of the motored case, and temperature of iso-octane injection cases was even lower than that of n-heptane injection cases. This indicates, even if vaporization effect seemed to be the same at both injection cases, the effect of temperature decrease changed due to the chemical reaction effect for the n-heptane cases. Chemical reaction seems to be initiated outside of the fuel liquid spray and the position was moving towards the fuel rich area as the time proceeds.

High fuel efficiency and low emission technologies, such as Direct Injection (DI) gasoline and diesel engines and hybrid powertrains, have been developed to resolve environmental and energy resource issues. The hybrid powertrain system has achieved superior power performance as well as higher system efficiency and is expected to be a core powertrain technology because it is compatible with various power sources including fuel cells. It becomes important to control complicated hybrid systems that consist of not only a powertrain but also vehicle systems such as regenerative braking. Model-based control and calibration enables both control strategy optimization and control system development efficiency improvement.

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.

New engine controls have been developed for the turbocharged Lexus NX200t to improve driving power by reducing engine torque output lag. Drive power management functions have been centralized in an integrated drive power control system. The newly developed controls minimize the potential reduction in drivability associated with the adoption of a turbocharged engine while improving fuel efficiency. General driveability issues commonly associated with a turbocharged engine include sudden increases in drive power due to the response lag of the turbocharger, and higher shifting frequencies if this response lag triggers a disturbed accelerator operation pattern by the driver. The developed technologies detect and control sudden increases in drive power to create the optimum drive power map, and reduce unnecessary shifts even if the driver's accelerator operation is disturbed.

TOYOTA has developed a new automatic transmission, called the A341E. This transmission employs a unique engine and transmission integrated intelligent control system named “ECT-i”, and a high performance “Super Flow” Torque Converter. This control system is capable of total control of engine torque and clutch hydraulic pressure during shifting, which has resulted in very smooth shift without changes over the life of the transmission. The “Super Flow” Torque Converter has a modified geometry optimized by the analysis of internal flow by means of computer simulations, attaining the highest efficiecy in the world. With the use of such systems, this new automatic transmission has improved total performance of the vehicle.

Newly developed 2VZ-FE engine for CAMRY is a 2.5-liter water cooled and V-type 6-cylinder engine exported from TOYOTA for the first time. This engine has the TOYOTA original 4-valve DOHC system. That is, exhaust camshafts driven by intake camshafts using scissors gears. By its compact configuration with the gear driven camshafts, this V-type 6-cylinder engine is mounted on a front-wheel-drive vehicle which originally had an in-line 4-cylinder engine. By increasing IVZ-FE engine displacement (for domestic), compact pentroof-type combustion chambers, optimum air-fuel ratio and ignition timing by TCCS (TOYOTA Computer Controlled System) and other technologies, a high performance 153HP/5600rpm and a large torque 155ft·lbs/4400rpm have been achieved with a low fuel consumption.

The purpose of this paper is to construct the thermal analysis model by measuring and estimating the temperature at the traction contact area. For measurement of temperature, we have used a thin-film temperature sensor. For estimation of temperature, we have composed the thermal analysis model. The thin-film temperature sensor was formed on the contact surface using a spattering device. The sensor is constituted of three layers (sensor layer, insulation layer and intermediate layer). Dimensions of the sensor were sufficiently smaller than the traction contact area. The sensor featured high specific pressure capacity and high speed responsiveness. The thermal analysis model was mainly composed of three equations: Carslaw & Jaeger equation, Rashid & Seireg equation and heat transfer equation of shear heating in oil film. The heat transfer equation involved two models (local shear heating model at middle plane, homogeneous shear heating model).

In an evaluation of crashworthiness for the cars made of aluminum alloys, the evaluation considering fracture phenomenon comes to be needed because conventional aluminum alloys have low fracture strain (10-20%). In case of the development of a B-Pillar made by die cast, if crack occurrence, furthermore, separation of a part can be estimated by using CAE in crashworthiness evaluations, we can reduce the number of prototype makings and the cost of development using expensive dies. Therefore, we performed crashworthiness evaluations by CAE using some sort of a damage & fracture material model. It is known as “Orthotropic damage & fracture model”.

It has been reported that engine oils containing magnesium detergents gel under special conditions. The authors have previously reported on the mechanism by which magnesium detergents form needle crystals, which is the main cause of the gelation[1]. For this article, the authors conducted tests in actual vehicles using several types of engine oils containing magnesium detergents, including oils for which gelation problems have been reported in the market. The gelation was reproduced, and the test oils were ranked by their propensity to gel. In addition, a laboratory test method was used in which water and CO2 were mixed into engine oil under controlled conditions, then left stored in a bottle for twenty days, after which the kinematic viscosity and the quantity of insolubles of the mixture were measured. The study demonstrated the correlation between the laboratory test method and the actual vehicle tests.

Recently, the demands of vehicle owners have become more diversified. This is particularly true in the paint appearance of the vehicle. Responding to these demands Toyota has developed an ink jet painting system, Toyota Fantasy Print System. This system can illustrate practically any picture which the customer desires. The system utilized a subtractive method of paint mixture which mixes or piles up these four permeable inks. The development of durable ink as well as equipment which can efficiently and effectively apply the ink onto the required contoured surface.

For viscous couplings(VCs) as a driving force transmission system of vehicles, requirement of torque characteristics has been getting very stringent. Because the torque characteristics significantly affect four wheel drive vehicles' abilities such as traction performance and driving stability. Furthermore, the recent concerns on high fuel economy, low pollution and low cost require that design of VCs should be increasingly compact, light weighted and excellent in transmitted torque's stability. It is an easy way to increase viscosity of viscous coupling fluids(VCFs) for the compact design of the VC. But it might cause increase in heat load and wear of plates which resulted in degradation of the VCF. The degradation affects VCF's viscosity and impairs stability in torque transmission. Therefore it is indispensable to develop high viscosity VCF which is excellent in long-term viscosity's stability.

In 2007, researchers at the Massachusetts Institute of Technology successfully completed a Wireless Power Transfer (WPT) experiment. Ever since, interest in WPT has been growing. At Toyota, we have been developing the underlying technology of a WPT system. Simultaneously we have been working with regulatory committees to create a standard for WPT. In particular, there are concerns that WPT’s radiated emissions could cause harm to humans and the neighboring electronic equipment. There are many challenges that need to be overcome, but a key concern is understanding WPT’s electromagnetic compatibility (EMI: Electro-Magnetic Interference and EMF: Electro-Magnetic Field). In this paper, we show the technical issues, the evaluation method, and the development status of EMI and EMF on PHVs/EVs when using WPT. For Electromagnetic interference (EMI) performance, we investigated both an open area test site and an electromagnetic anechoic chamber as evaluation environments.

In order to achieve the Toyota Environmental Challenge of 2050 (zero CO2 emissions), we have developed an innovative coating system that achieves more than 95% transfer efficiency. In order to reduce paint loss in the painting process, it is necessary to eliminate overdust and bounce dust. The most important point is how to spray (atomization, particle flight, adhesion) without shaping air. We have developed a “super high transfer efficiency system” that eliminates the need for shaping air. We continue to challenge the development of innovative technologies to view the paint shop as clean and eco-friendly environment.