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In recent years, improvements in the fuel economy and exhaust emission performance of internal combustion engines have been increasingly required by regulatory agencies. One of the salient concerns regarding general purpose engines is the larger amount of CO emissions with which they are associated, compared with CO emissions from automobile engines. To reduce CO and other exhaust emissions while maintaining high fuel efficiency, the optimization of total engine system, including various design parameters, is essential. In the engine system optimization process, cycle simulation using 0-D and 1-D engine models are highly useful. To define an optimum design, the model used for the cycle simulation must be capable of predicting the effects of various parameters on the engine performance. In this study, a model for predicting the performance of a general purpose SI (Spark Ignited) engine is developed based on the commercially available engine simulation software, GT-POWER.

A hybrid simulation model in the transient bench was developed to realize the characteristics of the transient behavior and the fuel economy equivalent to that of a real vehicle. The motors and the batteries that were main components of the hybrid vehicle system were simulated as constructive modules, the functions of which have the integrated control and the input/output (I/O) function with real components. This model enabled us to accommodate a variety of auxiliary (AUX) I/O flexibly. The accuracy of the model was verified by the transient characteristics of the engine and the fuel economy result through correlation with a mass-produced vehicle. Furthermore, the flexibility of the model to a variety of AUX I/O was examined from the simulation test of the vehicle equipped with the waste heat recovery (WHR) system.

In recent years, electrification of powertrains has been promoted to improve fuel efficiency and CO2 emissions. Along with electrification, it is possible to reduce engine usage frequency and improve the fuel efficiency in traveling. Especially in a hybrid electric vehicle (HEV), the state changes from motor assist mode to engine firing mode. As a result, stay time in eigenvalue of a powertrain is shortened, and vibration of the vehicle body at the engine start situation is able to be reduced as compared with conventional engine-driven vehicle. However, since the HEV is equipped with a high compression ratio engine for improving fuel economy, there is cause for concern that excitation force generated by the powertrain at the time of engine start increases. Also, the vehicle body vibration at engine start situations requires further consideration, because the operation frequency of engine decreases.

In recent years, the slip lock-up mechanism has been adopted widely, because of its fuel efficiency and its ability to improve NVH. This necessitates that the automatic transmission fluid (ATF) used in automatic transmissions with slip lock-up clutches requires anti-shudder performance characteristics. The test methods used to evaluate the anti-shudder performance of an ATF can be classified roughly into two types. One is specified to measure whether a μ-V slope of the ATF is positive or negative, the other is the evaluation of the shudder occurrence in the practical vehicle. The former are μ-V property tests from MERCON® V, ATF+4®, and JASO M349-98, the latter is the vehicle test from DEXRON®-III. Additionally, in the evaluation of the μ-V property, there are two tests using the modified SAE No.2 friction machine and the modified low velocity friction apparatus (LVFA).

Idling stop systems are being increasingly adopted in conventional engine vehicles as well as hybrid electric vehicles to increase fuel efficiency. When the engine starts, body vibration occurs that is caused by the rigid body eigenvalues of the power plant during initial combustion. Engine restart vibration after an idling stop is caused by the input force from the transmission, and the reaction force from the drive shaft as well as the input force from the engine. This phenomenon occurs frequently when the engine is restarted from the idling stop, the vibration is increasingly annoying to passengers. Usually, the vehicle development process is carried out in accordance with the V process. The V process divides the vehicle development process into two stages. The first stage is called the vehicle design stage to determine the characteristic. The second stage is called the vehicle verification stage to verify the performance.

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.

A new electric power steering (EPS) was developed which uses an electric motor to provide assistance. It is a system combinning the latest in power electronics and high power motor technologies. The development was aimed at enhancing the existing hydraulic power steering's energy efficiency, driver comfort as well as increasing active stability. This paper describies the overall concept of EPS and outlines the components and control strategies using electronics. The EPS was tested on a front wheel drive vehicle weighing 1000kg in front axle load. The results showed a 5.5% improvement in fuel economy. The EPS has also achieved returnability that gives the driver more moderate feelings matching the vehicle in action as well as the active stability control strategy for high speed driving.

In 2002, to address environmental and energy issues, Honda began to deliver a fuel cell vehicle, the FCX. Now, Honda has developed a new model FCX, which is able to operate in cold regions with significantly enhanced driving performance, in an attempt to increase the popularity of fuel cell vehicles in the world. The new vehicle employs Hondas next-generation fuel cell stack which enables start-up and allows for power generation at - 20 ° C, and Honda has delivered new FCXs to customers where winter temperatures fall to -20 ° C--in New York state, US and Hokkaido, Japan-leading the world. As the motor power-output has been increased to 80kW increases in both the power-output of the fuel cell stack and the energy capacity of the ultra-capacitors have enabled an increased supply of power to ° the motor, resulting in significant enhancement of both initial and overtake acceleration performance.

A CVT for midsize vehicles was developed that simultaneously achieves high levels of fuel efficiency performance and driving enjoyment, and marketability enabling deployment to global markets, and support for high-torque direct injection engines. This was done by modifying the CVT for 2.4 L-class vehicles sold in Japan, expanding the ratio range, using CVTF with a high friction-coefficient that simultaneously realizes both high efficiency and a high transmission capacity. This enabled achievement of an overall length of 386.5 mm, total weight of 96.1 kg, and maximum transmission torque of 270 Nm, and also enhanced fuel efficiency by approximately 10% (EAP fuel economy label) compared to the 2008 model year Accord 5AT and approximately 5% (JC08) compared to the 2010 model year STEP WGN CVT. Thus, CVT performance was obtained that can simultaneously realize high levels of both fuel efficiency and driving enjoyment.

The technology for a new, high-strength piston material has been developed by using high pressure die casting (HPDC) method, which had a rapid rate of solidification. This method allowed the amount of Ni added to be increased to 5.5 mass%, raising the fatigue strength of the new material at temperatures of 523 K or higher by a factor of 1.5 over that of a conventional material made by gravity die casting (GDC). In addition, application of vacuum to the die cavity and using additional pressure enabled quality exceeding that of conventional GDC pistons. Pistons made from the newly developed material decreased engine friction by 4.4% and increased fuel efficiency by 2.2% in engine bench testing.

Honda has employed IMA (Integrated Motor Assist) technology in the 2006 Civic Hybrid to enhance fuel efficiency and improve dynamic performance of a compact 4-door sedan. Our objective in developing the motor in the IMA system was to increase power, torque, and efficiency while maintaining the size of a previous motor. To achieve this aim, we focused on the following points: IPM (Interior Permanent Magnet) rotor structure High performance magnet Flat wire coil Polygonal bus ring structure Integrated 3-phase connector As a result, motor power was increased by 50% and achieved a 3 point average increase in efficiency, enabling vehicle dynamic performance and fuel efficiency objectives to be achieved.

A new control system using O₂ feedback control has been developed as an alternative to intake air pressure sensors. This control method uses the operational condition compensation coefficient Kbu. This coefficient encompasses the state of the engine and environmental conditions such as atmospheric pressure, and corrects fuel injection in response to changes in these factors. Kbu makes it possible to control the amount of fuel injection without depending on an intake air pressure sensor. It also makes it possible to carry out the appropriate air-fuel ratio correction even at times when O₂ feedback control is not operating, such as the cold period, when the engine is first started, or during transient operation, by using Kbu values recorded in the Engine Control Unit (henceforth ECU).

Honda has developed a powertrain for 2013 subcompact class EVs. This powertrain has both high power and low loss in order to provide the EV with better marketability than existing EVs, with the world-best energy efficiency and class-exceeding dynamic performance. To achieve the energy efficiency, this powertrain also has a function of cooperative control with a newly developed electrically operated servo brake system. To achieve the high dynamic performance, a new rotor shape has been introduced to the electric motor, and the power control unit (PCU) is equipped with a high thermal conductivity heat sink. The battery system allows high output power in a compact structure because of a triple parallel module group configuration and an air-cooling system. As a result of these innovations in the powertrain, the vehicle attains 82 miles of driving range while achieving world-leading energy efficiency of 29kWh/100 miles.

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.

In the automobile industries, weight reduction has been investigated to improve fuel efficiency together with reduction of CO2 emission. In such circumstance, it becomes necessity to make an electric power steering (EPS) more compact and lightweight. In this study, we aimed to have a smaller and lighter EPS gear size by focusing on an impact load caused at steering end. In order to increase the shock absorption energy without increase of stopper bush size, we propose new theory of impact energy absorption by not only spring function but also friction, and a new stopper bush was designed on the basis of the theory. The profile of the new stopper bush is cylinder form with wedge-shaped grooves, and when the new stopper bush is compressed by the end of rack and the gear housing at steering end, it enables to expand the external diameter and produce friction. In this study, we considered the durability in the proposed profile.

The “RA168E”, a turbo-charged V-6 1.5-liter engine, was developed by Honda Motor Co., Ltd. for the 1988 Formula One Championship Race events. Despite boost restrictions (2.5bar), the engine boasts a maximum power of 504 kw (685 ps), which is equivalent to 336 kw/ℓ (457 ps/ℓ). The development of improvements on the fuel consumption of this engine allowed the achievement of a minimum brake specific fuel consumption of 272 g/kwh (200 g/Psh). This paper Introduces major specifications, along with power output and fuel consumption characteristics of the RA168E racing engine. In addition, the effects of intake air temperature, boost, air-fuel ratio, fuel temperature and fuel ingredients on fuel efficiency and power output are presented.

As the motorcycle market grows, the fuel efficiency of motorcycle oils is becoming an important issue due to concerns over the conservation of natural resources and the protection of the environment. Fuel efficient engine oils have been developed for passenger cars by moving to lower viscosity grades and formulating the additive package to reduce friction. Motorcycle oils, however, which operate in much higher temperature regimes, must also lubricate the transmission and the clutch, and provide gear protection. This makes their requirements fundamentally very different from passenger car oils. Developing fuel efficient motorcycle oils, therefore, can be a difficult challenge. Formulating to reduce friction may cause clutch slippage and reducing the viscosity grade in motorcycles must be done carefully due to the need for gear protection.

The chief goal of engineers studying internal combustion engines is to improve energy efficiency in the face of the increasingly severe global warming and energy issues. Hence, there have been numerous studies focusing on the combustion reactions in order to develop clean and reliable combustion that is capable of operating using less fuel. And to improve the comprehension of engine performance and its combustion reactions, development of comprehensive measurement technique for engine performance, in-cylinder visualization technique, and numerical simulations, is essential and strongly demanded. There have hitherto been numerous studies about combustion diagnostics and analysis, including high-efficiency measurement techniques using response surface method the air-fuel mixture distribution and flame propagation measurement with optical visualization techniques, and numerical calculations of combustion reaction with elementary reactions.

Bioethanol is being used as an alternative fuel throughout the world based on considerations of reduction of CO2 emissions and sustainability. It is widely known that ethanol has an advantage of high anti-knock quality. In order to use the ethanol in ethanol-blended gasoline to control knocking, the research discussed in this paper sought to develop a fuel separation system that would separate ethanol-blended gasoline into a high-octane-number fuel (high-ethanol-concentration fuel) and a low-octane-number fuel (low-ethanol-concentration fuel) in the vehicle. The research developed a small fuel separation system, and employed a layout in which the system was fitted in the fuel tank based on considerations of reducing the effect on cabin space and maintaining safety in the event of a collision. The total volume of the components fitted in the fuel tank is 6.6 liters.

A theoretical evaluation technology for timing chain systems in single-cylinder engine has been established. Hitherto, there have been almost no theoretical evaluation reports published about drive loss and slapping noise in cam drive systems including timing chains. Thus, tensioner lifter and tensioner guide specifications to satisfy requirements related to slapping noise and friction loss have been determined only by tests with actual engines. In this research, a highly accurate mechanism-simulation model has been constructed that takes into account factors such as dynamic characteristics along with crank sprocket and timing chain contact stiffness and friction coefficient in addition to static characteristics of the timing chain and tensioner guide. Our results have confirmed a high correlation with actual engine tests at an absolute value level.