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A dual piston Variable Compression Ratio (VCR) engine has been newly developed. This compact VCR system uses the inertia force and hydraulic pressure accompanying the reciprocating motion of the piston to raise and lower the outer piston and switches the compression ratio in two stages. For the torque characteristic enhancement and the knocking prevention when the compression ratio is being switched, it is necessary to carry out engine controls based on accurate compression ratio judgment. In order to accurately judge compression ratio switching timing, a control system employing the Hidden Markov Model (HMM) was used to analyze vibration generated during the compression ratio switching. Also, in order to realize smooth torque characteristics, an ignition timing control system that separately controls each cylinder and simultaneously performs knocking control was constructed.

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.

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).

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).

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.

The Honda variable valve timing and lift electronic control system (VTEC) is incorporated in the engine of the NSX sports car that is scheduled for sales in Europe this year. In the process of advancement of Honda's engine technology, VTEC was developed for much higher output and higher efficiency. This is actually the first system in the world that can simultaneously switch the timing and lift of the intake and exhaust valves. This system has made improvements in maximum output at high rpm, and also improved the low rpm range, such as idling stability and starting capability.

Power generation systems employed in small gas engine cogeneration were examined to compare losses in the converter, which converts three-phase alternator power to direct current (DC) voltage, and losses in the inverter, which converts power to high-quality alternating current (AC) voltage that can be connected into electric utility power lines. It is a characteristic of alternators that their efficiency and output voltage decline in the heavy load range. It was found, therefore, that step-down methods using thyristors operate in a low-efficiency range in order to provide a satisfactory supply of the targeted DC output voltage. Use of switching regulator methods, on the other hand, can generate the target voltage by regulating a switching device after first storing the alternator output in a choke coil. It was found, therefore, that these use the high-efficiency range of the alternator. The converter was found to have a resulting loss decrease of 19.4 W.

In conventional electronically controlled fuel injection systems, when the battery is inadequately charged, the small amount of electric power generated from the alternator by the kick starter operation is consumed by all electrical loads including the battery. This causes a voltage drop, hence the fuel injection system does not function due to a power shortage. To eliminate the power shortage, an installed relay circuit opens all electric loads other than the fuel injection system. This allows the fuel injection system to use all the electric power generated by the kick starter operation aided through using an additionally incorporated condenser. This type of electric power control system has been incorporated into the ECU. Thus, the control system has been realized that permits starting of an engine by using the kick-starter even when the battery is completely discharged.

A fuel-cell-vehicle has been provided with an electric-double-layer-capacitor system (capacitor) to act as a back-up power source. The fuel cells and the capacitor have different voltages when the system is started, and for this reason the system could not be reconnected by relays. A VCU (Voltage and current Control Unit) has been positioned in the path of electrical connection between the fuel cells and the capacitor as a method of dealing with this issue. The VCU enables the charging of the capacitor to be controlled in order to equalize the voltage of the two power sources and allow a connection.

Results are presented from an experimental study of the effects of engine speed and injection pressure transients on the cold start performance of a gasoline direct injection engine operating on iso-octane. The experiments are performed in an optically-accessible single-cylinder research engine modified for gasoline direct injection operation. In order to isolate the effects of the engine speed and injection pressure transients, three different cold start simulations are used. In the first cold start simulation the engine speed and injection pressure are constant. In the second cold start simulation the injection pressure is constant while the engine speed transient of an actual cold start is simulated. In the third cold start simulation both the engine speed and the injection pressure transients of an actual cold start are simulated.

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 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.

Traditionally, the suitability of wireless terminals for automotive use has been evaluated by conducting repeated driving tests in actual environments. However, this method of evaluation has long presented issues, and the implementation of the method itself is today becoming increasingly challenging. A method of evaluating the suitability of terminals for onboard use by generating virtual radio wave environments on a PC has therefore been developed by applying a two-stage method to multiple-input multiple-output (MIMO)-over-the-air(OTA) evaluation. The radio wave propagation characteristics necessary for the generation of these virtual radio wave environments are set using the multiple signal classification method incorporating an RF recorder. The research discussed in this paper used these methods to analyze the effect of the multipath distortion rate on sound quality in the reception of FM broadcasts.

Clarifying the impact of ETBE 8% blended fuel on current Japanese gasoline vehicles, under the Japan Clean Air Program II (JCAPII) we conducted exhaust emission tests, evaporative emission tests, durability tests on the exhaust after-treatment system, cold starting tests, and material immersion tests. ETBE 17% blended fuel was also investigated as a reference. The regulated exhaust emissions (CO, HC, and NOx) didn't increase with any increase of ETBE content in the fuel. In durability tests, no noticeable increase of exhaust emission after 40,000km was observed. In evaporative emissions tests, HSL (Hot Soak Loss) and DBL (Diurnal Breathing Loss) didn't increase. In cold starting tests, duration of cranking using ETBE 8% fuel was similar to that of ETBE 0%. In the material immersion tests, no influence of ETBE on these material properties was observed.

To enable a belt-driven Integrated Starter Generator (ISG) to be used in an idle-stop system, the belt system must be capable of both driving the accessories and of starting the engine. Conventional belt systems required a higher tension setting to accomplish this, and the associated increase in friction opposed the achievement of better fuel economy. In this research, an auto-tensioner with a contraction suppression function that utilizes the incompressibility of fluid as well as a belt system that enables the auto-tensioner to be optimally located were proposed. The behavior of the belt system was measured in detail by testing, and the cause of the fluctuation of the belt tension was clarified by analysis. A method of controlling the ISG torque to flatten out tension fluctuations was devised, and its effectiveness was confirmed by simulation and testing. From the overall results of the research, a belt system that does not require a high tension setting was realized.

An Integrated Motor Assist (IMA) system for the 2006 Civic Hybrid has been developed, with the goal of having class leading fuel economy among compact vehicles and enhanced driving performance. The IMA system has been enhanced for greater power and efficiency. Combining the 3-stage i-VTEC engine with a higher power, higher efficiency electric motor assist mechanism enables an increase in deceleration regeneration energy and a drive mode powered by the electric motor alone. The engine is a newly developed 3-stage i-VTEC, based on the 1.3L SOHC i-DSI engine. The new 3-stage i-VTEC engine incorporates both a VTEC mechanism that switches cam profiles in low and high engine speed ranges, and a cylinder deactivation mechanism. The CVT has both an expanded ratio range and a higher final gear ratio. Through these technological enhancements, we have achieved the highest levels of fuel economy in the compact class and enhanced acceleration performance.

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.

Ultra-low energy consumption and ultra-low emission vehicle technologies have been developed by combining petroleum-alternative clean energy with a hybrid electric vehicle (HEV) system. Their component technologies cover a wide range of vehicle types, such as passenger cars, delivery trucks, and city buses, adsorbed natural gas (ANG), compressed natural gas (CNG), and dimethyl ether (DME) as fuels, series (S-HEV) and series/parallel (SP-HEV) for hybrid types, and as energy storage systems (ESSs), flywheel batteries (FWBs), capacitors, and lithium-ion (Li-ion) batteries. Evaluation tests confirmed that the energy consumption of the developed vehicles is 1/2 of that of conventional diesel vehicles, and the exhaust emission levels are comparable to Japan's ultra-low emission vehicle (J-ULEV) level.

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.