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Titanium alloy for forging and pure titanium material for exhaust systems have been developed. The forging alloy will be applied to production of lightweight motorcycle frames and the pure titanium will be applied to improve engine performance. The materials have been made inexpensive by the use of off-grade sponge that includes many impurities for production of titanium ingot. Stable characteristics have been obtained by controlling oxygen equivalent after setting the volume of tolerable impurities by considering mechanical properties and production engineering. In spite of low-cost, the material provides the same design strength compared to conventional material, and enables parts production with existing equipment. A review of manufacturing and surface treatment processes indicated a reduction in the price of titanium parts produced with this new material.

In this research, a material model was developed that has orthotropic properties with respect to in-plane damage to support finite element strength analysis of components manufactured from a randomly oriented long-fiber thermoplastic composite. This is a composite material with randomly oriented bundles of carbon fibers that are approximately one inch in length. A macroscopic characteristic of the material is isotropic in in-plane terms, but there are differences in the tension and compression damage properties. In consideration of these characteristics, a material model was developed in which the damage evolution rate is correlated with thermodynamic force and stress triaxiality. In-plane damage was assumed to be isotropic with respect to the elements. In order to validate this material model, the results from simulation and three-point bending tests of closed-hat-section beams were compared and found to present a close correlation.

Lithium-rich layered oxide, expressed as xLi2MnO3-(1-x) LiMO2 (M = Ni, Co, Mn, etc.), exhibits a high discharge capacity of 200 mAh/g or more and a high discharge voltage at a charge of 4.5 V or more. Some existing reports on cathode materials state that lithium-rich layered oxide is currently the most promising candidate as an active material for high-energy-density lithium-ion cells, but there are few reports on the degradation mechanism. Therefore, this study created a prototype cell using a lithium-rich layered cathode and a graphite anode, and analyzed the degradation mechanism due to charge and discharge. In order to investigate the causes of degradation, changes in the bulk structure and surface structure of the active material were analyzed using high-resolution X-ray diffraction (HRXRD), a transmission electron microscope (TEM), X-ray absorption fine structure (XAFS), and scanning electron microscope/energy dispersive X-ray spectroscopy (SEM-EDX).

In order to reduce emissions and enhance energy security, renewable power sources are being introduced proactively. As the fraction of these sources on a power grid grows, it will become more difficult to maintain balance between renewable power supply and coincident demand, because renewable power generation changes frequently and significantly, depending on weather conditions. As a means of resolving this imbalance between supply and demand, vehicle-to-grid (V2G) technology is being discussed, because it enables vehicles to contribute to stabilizing the power grid by utilizing on-board batteries as a distributed energy resource as well as an energy storage for propulsion. The authors have built a plug-in vehicle with a capability of backfeeding to the power grid, by integrating a bi-directional on-board AC/DC and DC/AC converter (on-board charger) and a digital communication device into the vehicle. The vehicle is interconnected to a power regulation market in the United States.

In recent years, the reduction of CO₂ emissions is under way, and the expectancy for electrical power is getting bigger for motorcycles as well. This time, an electric motorcycle with good driving performance, adequate range and quick charging performances for business use has been developed using a small battery. The travel modes have been investigated for business applications of delivery services to classify the traveling patterns and the objectives have been settled based on them. The energy efficiency has been improved by the application of the smallest amount of battery and by the integrated power unit configuration. With this achievement, the range of 34 km (at a constant speed of 30 km/h) has been realized while maintaining the 12-degree hill-climbing departure performance when loaded with a rider and a 30 kg load, which is the requirement of performance for business use.

Honda has developed the 2018 model CLARITY PLUG-IN HYBRID. Honda’s new plug-in hybrid is a midsize sedan and shares a body platform with the CLARITY FUEL CELL and the CLARITY ELECTRIC. The vehicle’s electric powertrain boosts driving performance as an electric vehicle (EV) over Honda’s previous plug-in hybrid. The CLARITY PLUG-IN HYBRID’s electric powertrain consists of a traction motor and generator built into the transmission, a Power Control Unit (PCU) positioned above the transmission, an Intelligent Power Unit (IPU) fitted under the floor, and an onboard charger fitted below the rear trunk. The PCU integrates an inverter that drives the traction motor, an inverter that drives the generator, and a DC-DC converter to boost battery voltage (referred to as a “Voltage Control Unit (VCU)” below).

Honda has developed an electric powertrain for a 2017 plug-in hybrid vehicle using its second-generation SPORT HYBRID i-MMD powertrain system as a base. The application of the newly developed powertrain system realizes a long all-electric range (AER), allowing operation as an EV for almost all everyday driving scenarios, with dynamic performance making it possible for the vehicle to operate as an EV across the entire speed range, up to a maximum speed of 100 mph. The amount of assist provided by power from the batteries during acceleration has been increased, helping to downsize the engine while also balancing powerful acceleration with quietness achieved by controlling racing of the engine. In order to realize this EV performance with the second-generation SPORT HYBRID i-MMD system as the base, it was necessary to increase the power output of the DC-DC converter, taking restrictions on space into consideration.

Technologies related to electrical systems for the 2011 hybrid model have been developed. In order to increase energy recovery during driving, improvements were made compared to the 2006 model in terms of motor output increase and high-efficiency range expansion, and considerations were also given to motor NV (noise and vibration). In consideration of vehicle control associated with the use of lithium-ion batteries (LIBs) as well as reliability, a system to control effective use of battery performance was developed which involves detection of battery conditions. Control of energy management was optimized compared to nickel metal hydride (NiMH) batteries through the use of higher-output LIBs and a high-output motor.

A compact intelligent power unit capable of being installed under the rear seating was developed for the 2018 model year Accord Hybrid that is to be equipped with the SPORT HYBRID Intelligent Multi Mode Drive (i-MMD) system. The space under the rear seat features multiple constraints on dimensions. In the longitudinal direction, it is necessary to attempt to help ensure occupant leg room and to position the fuel tank; in the vertical direction, it is necessary to attempt to help ensure occupants comfort and a minimum ground clearance; and in the lateral direction, it is necessary to avoid the position of the body side frames and the penetrating section of the exhaust pipe. The technologies described below were applied in order to reduce the size of components, making it possible to position the IPU amid these constraint conditions.

The mounting of lithium-ion batteries (LIB) in hybrid electric vehicles (HEV) calls for the configuration of highly robust control systems. When mounting LIBs in the vehicle, it is important to accurately ascertain and precisely control the state of the battery. In order to achieve high durability, it is important to configure highly reliable systems capable of dependably preventing overcharging as well as to have control technology based on software that can contribute to extended battery life. The system configuration applies an overcharge prevention system that uses voltage detection with an emphasis on reliability. Furthermore, a method for varying the range of state of charge (SOC) control in the vehicle according to the battery state is implemented to assure durability. In order to achieve this, battery-state detection technology was developed for the purpose of correctly detecting and judging the battery state.

A battery module structure and a battery management system that is optimal for the structure were developed, in order to facilitate the work of equipping hybrid cars with lithium-ion batteries (LIBs) that are expected to improve vehicle performance. This paper describes the structure of the LIB and the battery management system that is optimal for it. The battery module structure has cells with a sturdy holding structure and a highly efficient cooling system. The structure has enabled the improvement of battery pack system power output by 80% per unit weight and by 20% per unit volume compared to the previous model. The optimal management system prevents battery overcharge by detecting and controlling the state of charge (SOC) of each cell with a high degree of accuracy.

A new hydrogen fueling protocol named MC Formula Moto was developed for fuel cell motorcycles (FCM) with a smaller hydrogen storage capacity than those of light duty FC vehicles (FCV) currently covered in the SAE J2601 standard (over than 2kg storage). Building on the MC Formula based protocol from the 2016 SAE J2601 standard, numerous new techniques were developed and tested to accommodate the smaller storage capacity: an initial pressure estimation using the connection pulse, a fueling time counter which begins the main fueling time prior to the connection pulse, a pressure ramp rate fallback control, and other techniques. The MC Formula Moto fueling protocol has the potential to be implemented at current hydrogen stations intended for fueling of FCVs using protocols such as SAE J2601. This will allow FCMs to use the existing and rapidly growing hydrogen infrastructure, precluding the need for exclusive dispensers or stations.

A highly efficient two-motor plug-in hybrid system is developed to satisfy the global demands of CO2 reduction. This system switches three operation modes, what is called “EV Drive”, “Hybrid Drive” and “Engine Drive”, to maximize fuel efficiency according to the driving condition of the vehicle. Practical plug-in EV (Electric Vehicle) capability is also realized by adding a high-power on-board charger and a high capacity Li-ion battery to the original system. The outlines of the system components including a newly developed Atkinson cycle engine, a highly efficient electric coupled CVT (Continuously Variable Transmission) with built-in motor and generator, an integrated PCU (Power Control Unit) and an exclusive battery for plug-in HEV (Hybrid Electric Vehicle) are described in this paper. In addition to the switching of three driving modes and the efficiency improvement of each device, cooperative control of the hybrid system is introduced.

This paper explains the new methodology for post-crash fuel leakage testing of Fuel Cell Vehicles (FCVs) and other hydrogen vehicles utilizing compressed hydrogen storage systems. This methodology was incorporated into SAE J2578 that was revised and published in January, 2009. The new methodology is based on the concept in FMVSS 303 that specifies post-crash fuel leakage test method and criteria for CNG vehicle and adopted some modifications. Specifically, the following items are addressed: (1) Allowable leakage can be accurately evaluated in test even with large size tank that obtains only small pressure drop when a given amount of leakage occurs. A new method to deal with the influence of measurement errors was devised. (2) Even though only one option of test gas and initial filling pressure is accepted in FMVSS 303, new methodology for hydrogen system allows helium and hydrogen at reduced pressure as alternatives in addition to hydrogen at service pressure.

Appendix H of the SAE J2601 standard defines a development hydrogen fueling protocol named the MC Default Fill, which builds upon the foundation of the table based protocol, utilizing the same assumptions, boundary conditions, and process limits as the current standard. The MC Default Fill facilitates the following beyond the table based protocol: 1) the potential to provide faster, more consistent fueling times for fuel cell electric vehicle customers, and 2) the ability to continuously and dynamically adjust to a wide range of dispenser fuel delivery temperatures, allowing for more flexibility in station design. Computer simulations and laboratory bench tests were previously conducted and documented, validating the function and operation of the protocol.

As the electric vehicle (EV) market expands and we enter the period of fully fledged diffusion of the vehicles, evaluation of battery performance when secondhand vehicles are sold and when batteries are put to alternative uses will become increasingly important. However, the accurate measurement of battery performance for the purpose of battery evaluation represents a challenge when the batteries are fitted in a battery pack consisting of multiple cells. The authors therefore formulated a degradation estimation model for the evaluation of battery performance based on battery usage history. To formulate the model, parameters expressing the internal state of the battery are estimated from the battery's usage history; battery capacity is estimated with consideration of these parameters.

The development of Li-ion battery performance in next ten years will encourage improving a power density of Electric Vehicles (EVs). A higher voltage system with a boost voltage converter is favorable for the EV system if the converter has large power in small size. For increasing the converter power density, interleaved topologies using close-coupled inductors are shown to be superior. The inductor set of 3-phase type is proved to be smaller in size and lose less power in comparison to that of 2-phase type for high powered EV system having a 200∼400 volt battery. The prototype 3- phase converter using IGBT with 15 kHz switching frequency achieved a power density of 21.4 kW/liter at 120 kW output on a boost ratio of 1.38 with 98.0% efficiency, which also achieved more than 97% efficiency in a frequent usage zone.

Honda has been taking measures since the late 1990s to address three issues raised by the automobile, from air pollution, which was already a matter of regulation, to the additional issues of global warming and energy. With observation of recent trends in society, what had been our concern about these three matters appears to have gradually been turning into certainty instead. Meanwhile, the demand for automobiles is expected to increase with the population growth in newly emerging countries, economic growth, and other such factors. At present, with automobiles dependent on oil for the greater part of their energy, it has become a challenge to secure a stable supply of reasonably priced oil while the global warming perspective requires reduction of CO2 emissions. This article will review the history of development of the fuel cell vehicle (FCV) equipped with the next-generation power plant capable of simultaneously providing the solutions demanded for all three automobile issues.

A rubber sealing for a water-cooled battery pack plays a significant role to prevent water immersion into the inside of the pack. The appropriate design including the adjacent parts achieves a weight reduction of the battery pack by reducing the battery tray thickness and the quantity of bolts used in the whole battery pack. Generally, finite element analysis (FEA) is effective for the design optimization before proto-typing. However, the application to the sealing for a battery pack requires a large scale analysis, including the complicated contacts and large deformation of the rubber sealing, and results in unpractically long computation time and frequent computation errors due to the finite element distortion. A multi-scale structural analysis and the process on the rubber sealing for the battery pack has been developed to solve the above issues. This approach consists of 3 steps, which are single-unit, entire-scale and detailed structural analysis.

The dynamic performance of battery electric vehicles (BEV) is affected by battery output power, which depends on state of charge (SOC) and the temperature of battery cells. The temperature of the batteries varies in particular with the environment, in which the user stores the vehicle, and the battery output power. It is therefore necessary to employ thermal management systems that can control the battery temperature within the optimal range under severely hot and cold conditions in BEVs. A highly sophisticated thermal management system and its operation strategy were developed to fulfill the above requirements. The powertrain components to be thermo-controlled were located into two coolant circuits having different temperature range. The compact and efficient front-end heat exchangers were designed to optimally balance the cooling performance of powertrain, cabin comfort, vehicle aerodynamics and the vehicle design.