Demands for reducing exhaust emission and enhancing fuel economy have been increasing in accordance with growing concerns regarding global environmental issues. An electronically controlled fuel injection system which precisely controls the air-fuel ratio has been adopted to effectively meet the demands. Technologies for miniaturizing and achieving a high-efficiency system have been established for fuel injectors, the fuel pump and ECU (Electrical Control Unit). For the fuel injector, a spray form and magnetic circuit was optimized through computer simulation. As the result, a fuel injector with good installation ability for engine displacements ranging from 50 cm³ to 900 cm³ was realized. For the fuel pump, the maximized motor efficiency along with an optimized pump rotor shape reduced current consumption by 25%. For the ECU, the development of a circuit-integrated custom IC and the standardization of a housing achieved a compact, light, inexpensive design.

The next generation fuel cell stack employs an aromatic electrolyte membrane, which offers outstanding proton conductivity, a stamped metal separator formed with a unitized seal for superb electrical and thermal conductivity, and a simple stack structure which is obtained using the springiness of the stamped metal separators. The combination of these innovative new technologies enables the new fuel cell stack to achieve output density that ranks among the best in the world, to be half the size of its predecessor, and to operate in temperatures from -20 to +95 °C, leading to its enhanced environmental adaptability.

In order to maximize space efficiency in the fuel cell system box, the FCX uses two compact FC stacks. The resulting integrated module structure, with the humidifier unit, enables a more compact fuel cell system box to be achieved. Energy efficiency of the new fuel cell system has also increased over the previous model, due to the enhanced power generation efficiency of the fuel cell stack.

The 5-speed automatic transmission employed in the 2005 model year V6 Accord Hybrid was developed to enable the vehicle to display the powerful and refined driving performance of a V6 sedan, while achieving the fuel economy of a 4-cylinder compact sedan.

The Accord Hybrid represents the first combination of an IMA system and a stepped AT employing a torque converter. While its overall length has been reduced, the new AT has been designed with consideration of the high torque generated by the V6 3.0L i-VTEC engine and the IMA motor.

Expansion of the cylinder idling operating range and more effective regeneration of deceleration energy required a redesigned long torsion damper and a highly responsive lock-up clutch mechanism. The system has also been equipped with an electronic oil pump to enable smooth takeoff after idle stop, and a hydraulic system that employs a linear solenoid for direct control of all shift stages. The use of these new technologies has enabled the achievement of a superb balance of fuel economy and driving performance.

The SH-AWD system is a 4WD system providing continuously variable control of the torque transmitted to all four wheels to radically enhance vehicle dynamic performance. The core of the system is a direct electromagnetic clutch positioned in the rear drive unit. This new clutch was developed to enable more precise control than is possible in a conventional electromagnetic clutch. In the direct electromagnetic clutch, there is an air gap between the magnetic materials, that form the solenoid magnetic circuit. The solenoid force generated across this gap is converted into clutch thrust, without the need for the torque amplifier employed in conventional electromagnetic clutches. The fact that thrust acts directly on the clutch increases the precision of control. However, the size of the air gap changes when the thickness of the clutch changes, and this causes change in the solenoid force. A search coil is therefore used to detect changes in the size of the gap as changes in magnetic flux, enabling the current to be corrected in order to ensure that the appropriate solenoid force is consistently generated. In addition, measures to increase the accuracy of detection have enabled more precise control of torque transmission.

A material system has been developed to achieve the strength and durability required of a truck while maintaining the design flexibility required to produce a multi-piece truck bed with lockable under-floor storage. This system consists of a new structural SMC, a 2-part structural adhesive, and a spatter-applied 2K urethane coating. Material targets were developed considering both the particular usage of a truck bed and the over-arching goals of light-weight and excellent appearance. Each component was formulated to balance these requirements and validated through comprehensive specification tests including static strength, chemical and temperature durability, and other usage conditions.

A magnesium high-pressure diecast (Mg HPDC) intake manifold has been used in the newly developed V6 Integrated Motor Assist (IMA) engine on the ACCORD Hybrid for the North American market.

The body of the intake manifold features the same split structure used in the alminum high-pressure diecast (AI HPDC) intake manifold fitted in the Honda ELYSION. The two parts of the body are sealed with a formed in-place gasket (FIPG). This FIPG is also used in Honda’s high-pressure diecast magnesium transmission case. A modified version of a metal gasket has been used for the seal of fuel injector base.

The new magnesium high-pressure diecast (Mg HPDC) intake manifold is 44% lighter than a conventional aluminum low-pressure diecast (Al LPDC) intake manifold and 33% lighter than an Al HPDC intake manifold.

A non-contact measurement system has been used for the precision analysis of parts in 3D shape evaluation employing CAD data. In recent years, there have been attempts to utilize non-contact measurement systems to respond to demands for 3D shape evaluations of precision parts such as gears. However, there are various optical issues with conventional optical non-contact measurement systems. These issues had to be addressed for application to precision parts, necessitating the development of a new measurement system.

The sensor testing were conducted using a variety of optical sensors to clarify the specific issues arising in the measurement of precision parts with non-contact measurement systems, enabling the optimum optical sensors to be selected. The newly developed system employs two sensors, which enables the achievement of the level of accuracy required for 3D shape evaluation of parts. A multi-axis mechanism which compensates for the weak points of the optical sensors completes the new system.

This paper will demonstrate examples of the use of data measured by the developed measurement system.

Honda’s iGX440 general purpose engine utilizes electronic control technology to increase ease of use with high fuel economy and low noise performance.

The engine control system employs an electronic control unit (ECU) enabling more precise engine speed control in response to the numerous different operational requirements of a general purpose engine. This has resulted in an engine displaying power characteristics and operational performance meeting the requirements of users in a variety of different applications.

To increase the environmental friendliness of the engine, exhaust emissions have been reduced below regulation levels and fuel economy has been increased. In addition, the noise level of the engine has been reduced to meet Stage 2 requirements of the EU Directive on Noise Emission by Outdoor Equipment. This has been achieved mainly by reducing the noise generated by the mechanical system.

A precoated steel sheet fuel tank, a cold-forged camshaft, and a thermoplastic resin molded ECU have also been employed in the new engine.

The majority of electrical components utilized in general purpose work equipment are manufactured by potting employing thermosetting resins, taking into account their water, chemical and vibration resistance properties. The research discussed in this paper adopted a different approach, and attempted to mold these components using thermoplastic resins in order to reduce the size and weight of general purpose engines. Thermoplastic resin molding is typically only utilized when manufacturing small electrical components, due to the characteristics of the injection molding process. Molding conditions were optimized to enable the procedure to be employed for a large electronic circuit for engine control, a process which involved the study of resin materials and the layout of the electronic components, in addition to resin flow analysis. Manufacturing components using these optimized conditions enabled a 20% reduction in height and 50% reduction in weight of the control unit, in addition to reduction of the time required for the molding process.

General purpose engines are required to keep the engine speed constant, and are therefore equipped with governor mechanisms. However, the engines are applied to various applications, and the dynamic characteristics of the controlled engine changes according to different operating conditions. So it is necessary for a conventional mechanical governor to change the spring rate and tune the idle speed; similarly, gains must be tuned in electronic governors using PID control. To enhance robustness, an adaptive control system that uses a self-tuning regulator has been constructed. Applying elliptical gears to the mechanism for driving the throttle valve, it was possible to realize both high resolution near the closed position and a reduction in operating time of the throttle valve.

Honda has developed a turbo-charged common rail diesel engine for the European version of its CR-V Sports Utility Vehicle (SUV). During this development measures have been implemented to address the issue of the SUV body having high running resistance. The promotion of homogeneity in the air-fuel mixture through the employment of a shallow dish combustion chamber and the reduction of the diameter of the fuel injection nozzle holes has enhanced combustion and reduced engine-out Particulate Matter (PM). In addition, the use of a highly efficient EGR cooler has increased the volume of EGR. Combined with the achievement of optimal EGR gas temperature control by means of an EGR cooler bypass system, these factors together have enabled the achievement of a reduction in NOx emissions.

The enhancement in exhaust emission performance resulting from these innovations has made the CR-V the first SUV which is compliant with the 2005 European diesel exhaust emissions standards (EURO-IV).

A diesel particulate filter (DPF) is also employed in the CR-V. Optimization of the multi-fuel injection system, which is able to inject up to four times per cycle, control of the DPF temperature via the use of a variable geometry turbocharger (VGT), and intake control by means of the throttle valve have all resulted in reliable DPF regeneration performance.

These various emission reduction technologies have resulted in the achievement of PM emissions less than one-tenth of those stipulated by EURO-IV.

To enable a belt-drive Integrated Starter Generator (ISG) to be used in an idle stop system, the belt system must be capable of both driving the accessories and starting the engine. Accomplishing this with a conventional belt system required an increase in the tension of the belt, which also increased friction losses and is thus incompatible with the intention of increasing fuel economy.

Testing quantified the effect of the increased belt tension on increasing friction losses. With this knowledge the research team focused on the auto-tensioner mechanism and the design of a superior belt system without the requirement for an increase in tension. Belt tension was reduced through the employment of an auto-tensioner in which contraction can be controlled by exploiting the incompressibility of fluid and by modifying the belt layout to enable optimal positioning of the new auto-tensioner. The use of reverse torque was tested and proven to be an effective method of further reducing the tension of the belt. The combination of these innovations has resulted in the development of a superior belt system well matched to the requirements of an idle stop system.

Regulations relating to environmental noise generated by automobiles are becoming increasingly stringent, making it essential to develop simulation technologies to contribute to the reduction of exhaust noise. The authors attempted to make the pulsing exhaust flow produced by an internal combustion engine visible using Schlieren photography and to visualize the source of exhaust orifice noise using noise holography. The knowledge obtained from these experiments was used to develop an exhaust pulsating flow simulation technology for exhaust orifice noise that enables quantitative prediction of levels. The major components of exhaust orifice noise are compression waves and ring vortices; the new simulation technology enabled further clarification of the mechanism of production of this noise.

A noise generation mechanism of intermittent high-frequency noise during deceleration and high-frequency noise under load in a dual-thin-wall 4-in-1 exhaust manifold (hereinafter referred to as 4-1 manifold) have been investigated by using Computational Fluid Dynamics (CFD) and actual measurement of exhaust gas pressure fluctuation in the exhaust manifold. Modified gas flow in the exhaust manifold by CFD enabled a reduction actual exhaust gas pressure fluctuation, which is the excitation force, and actual radiated noise has been reduced.

A new engine mount system has been developed to enhance noise and vibration performance and driving comfort, and thus increase competitiveness, in the next generation compact car. The basic system configuration is a principal axis of inertia type mounting system with torque rods that display excellent vibration isolation performance. In addition, the following were employed as guidelines for system characteristics in order to maximize performance. (1) Rod transmission characteristic that increases vibration isolation, to reduce booming noise and engine noise. (2) Rod mounting direction that reduces body shaking when the accelerator pedal is employed. (3) Control of engine rigid body vibration modes to increase driving comfort. (4) Dynamic stiffness of mounting points to reduce engine noise. The achievement of these characteristics has enabled the development of an engine mount system for a highly competitive compact car platform.

A simulation method enabling simultaneous prediction of dynamic behavior and stress distribution on element has been developed for durability evaluation of dynamic strength of metal pushing V-belts. The finite-element-method that enables contact analyses in time history with large-scale model was adopted to reproduce the dynamic behavior of the V-belt in high rotational speed range of CVT. This paper focuses on the element strength in actual operation of CVT, and also discusses modifications made to the previously reported simulation method to enable the prediction of detailed stress. A new technique named inertia-relief is introduced needless of applying the constraint conditions when calculating the detailed stress on element in respectively. This results in allowing the stress distribution on any element to be found at any position on the trajectory of the V-belt. Using this technique, it has been found that the stress on the necks of elements at the entrance and exit of the pulleys affects the dynamic strength of the V-belt. Furthermore, a method of evaluating this stress was also determined. In addition, consideration was given to the effect of the elements tail side concave shape on the dynamic strength of the V-belt.

Previous studies have described a new analysis technique for objective measurements of passenger car steering systems carried out using the ISO standards. This analysis technique is based on deriving linearised stiffness and damping, which are objective metrics, from the non-linear results typically obtained for vehicles.

In this paper, the previous work is extended by carrying out a more comprehensive study of the correlation between these objective metrics and driver subjective assessments using a wide range of vehicles.

It is concluded that subjective assessments of on centre steering effort level, response level, friction and delay correlate well in many cases with the proposed objective metrics.

Assistance types and control methods were studied, in regard to the system to assist driver maneuvers in avoiding obstacles through steering. From the principle that the driver is the focal point of driving operation, a “driver reactive” type of assistance was selected, wherein assistance begins after the driver initiates an avoidance maneuver. Actualization of a four-wheel brake control that equivalently reduces vehicle yaw inertia moment and derivative steering characteristics has enabled the development of a steering reaction torque control system, which reduces driver avoidance operation delay, as a new avoidance assistance control method. Vehicle test results have confirmed that yaw rate gain during an avoidance maneuver rises a maximum of 1.5 times, and that steering delay can be reduced by a maximum of 700ms; these have led to enhanced driver avoidance maneuvers.

The conventional middle carbon non-heat-treated steel used in connecting rods has been used as a base in the development of a new material. High fatigue strength has been achieved by increasing the toughness of the ferrite, which tends to act as a crack origin, while optimal control of the reduction of toughness achieved through addition of Ti has been effective in enabling fracture splitting of the material.

Connecting rods produced using the new steel demonstrate 30% higher fatigue strength than connecting rods produced from conventional non-heat treated steel, and possess stable fracture splitting characteristics. In addition, the new connecting rods show identical strength to connecting rods made of the conventional material, but are 13% lighter.

The pistons are an essential element in the achievement of greater engine efficiency. A method of increasing the strength of the material employed in pistons to respond to increased thermal and mechanical loads and reducing weight has been developed to contribute to the quest for enhancements in power and fuel economy.

This method is used in the die cast production process, which has a rapid rate of cooling. The limit for addition of Ni to the aluminum alloy employed has been increased to 5.5mass%. At the same time, less than 0.4mass% of Fe is added and the Mn/Fe ratio is controlled to less than 0.6 in order to limit the coarsening of the crystals. This technique has increased the high-temperature fatigue strength of the material by more than 1.5 times against the material conventionally employed. In addition, the uses of die vacuum and additional pressure have enabled quality exceeding that of conventional GDC pistons.

Optimization of the piston shape to match the characteristics of the new material has resulted in decreasing engine friction by 4.4% and increasing fuel efficiency by 2.2% in engine bench testing.

Reduction of the precious metal loading of a catalyst generally causes a decline in light-off performance.

Study of the low temperature reaction mechanism of catalysts indicated the importance of the top layer in the reaction, thus increasing reactivity in the top layer was established as an objective. The concentration of precious metals in the top layer was increased, and the thickness of the layers was reduced. At the same time, the precious metal loading of the subjacent layer, which contributes little to light-off performance, was reduced by 80%. However, increasing the concentration of precious metals in the top layer caused a reduction in performance due to a sintering effect between the metals. Research was therefore conducted on the employment of a high-thermostability support material (alumina) to control the sintering.

This research has enabled the development of a three-way catalyst with significantly reduced precious metal loading while retaining conversion performance equivalent to that of conventional catalysts.

The quantitative evaluation of trapped air and strength of cast products at the completion of solidification in high pressure die-cast has been studied using material test and simulation. As a result, the prediction accuracy of trapped air analysis was enhanced by considering back pressure. In addition, by coupling the trapped air defect at the completion of flow with the solidification process, the analysis of mechanical characteristics of cast products has become possible.

Based on the injury assessment method established by ISO/CD 13232 and including neck injury assessment, which had not been established previously, the prototype airbag system was evaluated using full scale impact tests in seven configurations and computer simulation of 200 impact configurations, which calculate the process of dummies contacting the ground.
The GL1800 was used for this study; previous studies used the predecessor large touring motorcycle (GL1500). Furthermore, in addition to the assessment specified in ISO/CD 13232, tests using other configurations and other rider conditions were conducted. It was judged from the results obtained that an airbag system for a large touring motorcycle, like the GL1800, is feasible.

Honda has been developing computer simulation technology, capable to predict the injury levels, in tests from the start of a collision until the point where the dummy strikes the ground. This research shows the correlation between the computer simulations and full scale impact tests as specified in ISO/CD 13232. The results validate that computer simulation can predict the injury levels, from the start of collision until the point where the dummy strikes the ground. The performance and effectiveness of the airbag system for the GL1800 were evaluated in 200 impact configurations using the computer simulation specified in ISO/CD 13232. The results showed that the total average benefit was 0.048 and the total average risk was 0.004. The relative impact speed which demonstrated the highest effectiveness was 20-25 m/s.

Humans have a special ability for recognizing the face. We have proposed a new motorcycle design technique to enhance search performance using this ability. This technique uses shape recognition and light positioning.

Some experiments were carried out to measure brain activity while showing facial image stimuli. Results showed significant activity in the lateral fusiform gyrus (FFA). This implies that the brain analyzes our facial image stimuli as a human face.