The new model Inspire has been developed on the basis of the concept of a “New Intelligent Tourer.” The aim of development was to produce a new luxury sedan which would offer users a high degree of satisfaction through the achievement of superior performance in the basic requirements of luxury sedans while maximizing the advancement and sportiness for which Honda is noted.

Refined design gives the vehicle a tremendous sense of presence, individuality and quality, and offers a superbly quiet ride. The employment of numerous new technologies has enabled the complete realization of the development concept.

The followings have given the vehicle a level of advancement and sportiness that is unique to Honda: (1) the balance of incredible driving performance with high fuel economy by the V6 3.0L i-VTEC variable cylinder system engine; (2) the body and suspension which have been designed to provide a superbly comfortable ride that belies the power of the vehicle; and (3) the employment of HiDS to offer stress-free high-speed cruising and an advanced safety support system including collision mitigation braking (in a world first) and E-pretensioners.

This new luxury sedan is aptly named “Inspire,” offering as it does a level of driving appeal that competitors’ vehicles cannot match.

The new model Honda Life was developed on the basis of the concept of “Technology with Heart,” with a focus on the achievement of a high level of performance in the areas of safety, design, packaging, utility and driving. The engine, transmission and platform have been entirely redesigned to make the vehicle more compact, resulting in an increase of 95 mm in effective cabin area and enhanced collision safety performance. The vehicle has a high fuel economy of 19.8 km/l in Japanese 10-15 mode, and has received Ultra Low Emission Vehicle (ULEV) certification. The superior aerodynamic characteristics of the vehicle’s exterior provide a high level of driving stability and NV performance. With a front-to-rear walk-through seating arrangement, a multi-information display and a variety of other distinctive features, the new Life is a next-generation small car offering a high degree of utility and driving pleasure.

A prototype motorcycle "Super EARA", wheelchair users are able to ride on and off, drive and stop by themselves, has been developed. Function that the motorcycle should be equipped was considered in development. The function is starting, driving and stopping without using their lower limbs. A vehicle height adjusting system for riding on and off, outrigger and gas pressure type emergency stand to prevent stack are also equipped. It was confirmed that operation of equipment function is allowable by actual driving tests at Suzuka and Motegi circuits.

Honda has developed a 110kW (150hp) class outboard motor as the flagship model of its large, 4-stroke engine (4st) outboard series. A variety of technologies have been employed to increase power and reduce weight to produce a 4st engine in a horsepower class normally associated with 2-stroke engines (2st) and equal the performance of competitors’ 2st engines.

To increase the power of the engine, automotive engine technologies including DOHC-VTEC were employed, together with a dual control cooling system (unique to outboard motors) and a variable intake port system employing butterfly valves.

Improved performance was achieved through the application of weight saving technologies including a resin engine undercover manufactured using a new production process and a new oil case structure and the employment of a gear case that lowers the gear ratio to cope with the demands of the large propeller.

Increased fuel efficiency has been achieved through the employment of lean-burn using linear air/fuel ratio (LAF) sensor control in a world first for an outboard motor.

As a result of the technologies outlined above, a 15% increase in specific power (kW/L) has been achieved in the new outboard against previous Honda models. The motor satisfies the emission requirements stipulated in the 2008 CARB regulations while increasing fuel efficiency by 20% against the previous model in the same output range, and offers an excellent balance between running performance and fuel economy. In actual offshore use the top speed and acceleration of the new outboard match those of competitors’ 2st engines.

Honda has developed the first-ever 2.0L i-VTEC I direct injection gasoline engine employing a center injection system in which a high-pressure fuel injector is located in the center of the combustion chamber. This engine significantly improved fuel economy and emissions performance. Optimization of in-chamber fuel flow through redesign of piston shape and the spray characteristics of the high-pressure fuel injector and the application of VTEC has enabled the achievement of stable combustion of a stratified ultra-lean air-fuel mixture. Due to VTEC mechanism and the continuous variation of camshaft phase enabled by VTC, the engine has achieved top-class power for a high fuel economy engine. The new engine is fitted in the 2004 model Stream, and in combination with the CVT employed in the vehicle has enabled the Stream to achieve a low fuel consumption figure of 15.0 km/l in Japanese 10-15 mode. A large amount of EGR and a high-performance lean NOx catalyst to reduce emissions has further enabled the Stream to become the first vehicle with an engine employing ultra-lean stratified charge combustion to achieve an emissions level of only 25% of the level stipulated by the Japanese 2000 emissions regulations and obtain Ultra Low Emission Vehicle (ULEV) certification.

A center injection system in which a high-pressure fuel injector is located in the center of the combustion chamber has been employed in a newly developed direct injection gasoline engine. The high-pressure fuel injector is highly responsive, with a minimum injection timing of 0.7 msec, and injects an ultra-atomization spray with an average droplet diameter of less than 12μm. To ensure durability and reliability in this original center injection system, the high-pressure fuel injector mounting employs a layout in which the unit is secured by arms. The design of the high-pressure fuel supply lines was optimized using simulations, and the reduction of stress and the adoption of a structure to damp fuel pulsation have resulted in the achievement of high reliability. A simple plunger and spill solenoid system has been employed in the high-pressure fuel pump, enabling the required driving force to be reduced, the component to be reduced in size, and the achievement of high-accuracy fuel pressure control.

The world’s first electronically controlled hydraulic steering damper for motorcycles, HESD (Honda Electronic Steering Damper), has been developed. That always gives optimum damping characteristics during running. Handling characteristics and “Kickback” phenomenon was analyzed using a motorcycle with or without a steering damper. The steering damper with optimum damping characteristics according to the speed and acceleration of vehicle is needed to reduce “Kickback” phenomenon. An electronically controlled linear solenoid is applied to alter flow resistance of the damper. The HESD reduced kickbacks maintaining sporty handling at the low speed running.

An electronic control system has been developed for a small snow thrower for general home use. The new system provides stable propulsion and smooth turning. Development focused on the major requirements of snow thrower stable behavior in changing conditions and responsiveness to operator input. The new system has eliminated the need for troublesome speed control, and even complicated turning maneuvers can be conducted more easily. Both high torque and high speed are required from the drive motor, which employs a 12V battery power supply. A brushless DC motor was utilized and flux-weakening control was adopted to enable these requirements to be balanced. The new control system has enabled the achievement of good performance, and integration of components has resulted in a 10% reduction in the volume of components for the former medium hybrid snow thrower.

The use of different casting methods causes differences in the detailed shapes of mass-production and prototype models of the hydraulic valve bodies which make up the hydraulic circuits employed for shift control in automatic transmissions. These differences make it necessary to reset the shift control specifications in mass-production models after their initial setting in the prototypes. This issue could be resolved by replacing the sand molds currently used to cast prototypes with the dies used in mass production, but the length of time required to produce prototypes with the dies renders this method impractical. New production techniques were therefore proposed and the production workflow was studied to reduce the period required to produce dies. As a result, prototype hydraulic valve bodies can now be produced using dies in a shorter period than previously required when using sand molds.

Honda’s Data Proto Model (DPM) is a digitally-modeled prototype vehicle generated through the formulation of three-dimensional data for a complete vehicle and the input of the collected data into a computer. This paper discusses the development of two three-dimensional modeling systems for the vehicle body, which forms part of the DPM. One of these systems makes use of global time differences to enable modeling before the issue of design drawings, making an image of the latest body constantly available to designers. The other is a modeling system based on the BOM (Bill of material) established after the issue of design drawings. These systems enable other designers and members of the manufacturing division to refer on a daily basis to the latest form of the body. The DPM also enables constant review of specifications in the initial stages of design. A system was developed to facilitate DPM verification meetings; these bring together specialists to run checks on interference between components, review the design layout, etc., using DPM. As a result, any designer is able to use DPM for verification of the appropriateness of design, and the system is now in use in Honda’s design departments.

A V6 i-VTEC engine provided with a variable cylinder system has been developed to achieve high output, high fuel economy and low emissions. The variable cylinder system uses the VTEC mechanism to close the rear bank of three cylinders. To increase the accuracy of switching control, it is essential to increase the responsiveness of switching when oil pressure is low at low engine speeds. High responsiveness has been ensured in this engine by contriving the way of switching synchro pin and spool valves. The increased accuracy of control has enabled valve close timing to be synchronized with the stopping of fuel supply to the deactivated cylinder bank. As a result, the system is able to switch instantaneously between three- and six-cylinder operation to enable engine output to respond to the different driving conditions with no loss of drivability. The new engine has been employed in the new model INSPIRE. It is a high-power (184 kW [250 ps]) and high-torque (296 Nm [30.2 kgm]) engine, and achieves a fuel consumption of 11.6 km/l in Japanese 10-15 mode and meets ultra-low emissions standards while maintaining regular gasoline specifications.

A 660cm³ 3-cylinder engine has been developed for the new model of the Honda Life. The basic structure of the engine has been redesigned to achieve improved environmental performance, increased compactness and weight savings, and a higher level of quietness.

The development concept was to produce an engine that excelled under normal driving conditions. To respond to the high frequency of high engine loads and engine speeds in minicars, the i-DSI engine employs a short stroke to reduce friction. The use of i-DSI twin plug ensures rapid combustion, enabling fuel economy and output to be increased through the use of a high compression ratio.

The innovations outlined above have increased torque by 7% under normal driving conditions, and enabled the achievement of a class-topping fuel economy of 19.8 km/ L in Japanese 10-15 mode. The increased idling fuel economy achieved by improved combustion and reduced emissions and NV make the new engine an extremely high-quality unit.

Honda has developed its first 2.2L 4-cylinder diesel engine for the 2004 model Accord to be marketed in Europe.

The newly developed engine has a number of distinctive features. The employment of the latest 1600 bar common rail control system, an EGR cooler and an after-treatment system has enabled the engine to comply with the EURO-IV regulations. The application of a variety of technologies to make the engine both lighter and more compact, including the employment of a cylinder block manufactured using a new casting process, and the use of advanced combustion and friction reduction technologies have resulted in a balance of power output, fuel efficiency and quietness at the top of this engine class. The employment of these original technologies has enabled the full realization of the development concept, which stressed power and refinement, and the Accord has been well received in the European market.

A high-strength aluminum cylinder block manufactured using a new production process, ASCT (Advanced Semisolid Casting Technorogy) has been adopted for the newly developed 2.2L 4-cylinder i-CTDi (Intelligent Common rail Turbo Diesel Injection) diesel engine fitted in the new Accord to be marketed in Europe. In the production process, the semi-solid aluminum is used during high pressure die-casting. In addition, newly developed pressure-proof sand core are used to mold the closed deck, and heat treatment is conducted to ensure the high level of materials strength.

To respond to the high load on the crankshaft journal, die-cast aluminum lower blocks, in which the cast iron bearing caps are included, are employed. Adopting the dummy head honing and offset cylinders to reduce bore deformation have enabled the achievement a lightweight and compact cylinder configuration matched to the high combustion pressure of the latest diesel engines, while maintaining a high level of quietness.

Thanks to these measurements, 30% of weight reduction in the new cylinder block has been achieved compared to that of the conventional cast iron diesel engines of the same displacement.

Cooling performance of the outboard engines, which pump the ambient water to cool the engine and discharge it to the ocean or rivers, has been improved in a direct-cooled outboard motor without a radiator in order to increase knock limit.

The research project leading to this improvement tested a conventional single control cooling system and a new dual control cooling system in which the cylinder head and cylinder blocks were made independent and each provided with a thermostat to enable temperature to be controlled.

Tests were conducted under full engine load. Measurements of the temperature of cooling water inside the water jacket were taken to evaluate cooling performance. Knock limit was evaluated through measurements of combustion chamber pressure taken using a gasket type combustion pressure sensor positioned at the spark plugs.

These measurements confirmed that the dual control cooling system increased knock limit by 8 deg against the conventional single control cooling system.

A torque on demand 4WD system has been developed with a front engine front drive vehicle as a base to balance traction performance and handling characteristics with fuel efficiency in a minivan. The response of torque to front-rear wheel rotation speed difference were studied to ensure superior traction performance and handling characteristics. The use of an initial torque between the front and rear wheels was considered as a method of improving the response of torque transmitted to the rear wheels when the front wheels slip. Using the Honda dual pump system as a reference, the results of calculations of the required traction force on snow and actual measurement values for tire traction characteristics were employed to find the optimal torque characteristic. As a result, 25% of maximum necessary torque was established as the ideal initial torque. A comparison of the optimal torque characteristic with the torque characteristic of the dual pump system in a simulation of vehicle starting on snow confirmed the effectiveness of the initial torque. It was possible to achieve the optimal torque characteristic with a simple mechanical structure. A one-way cam and a preset pilot clutch were added to the rear final drive unit of the dual pump system. Good fuel efficiency was ensured through setting an appropriate gear ratio for the rear final drive unit. As a result, the newly developed minivan 4WD system meets vehicle performance requirements while weighing only 54kg, making it the lightest in its class.

A highly accurate method was developed for simulating the operating force for the select lever of an automobile automatic transmission by considering the internal link mechanism, the contact between parts, the load loss in the wire, and other factors. In order to improve accuracy, an experimental formula was introduced that takes the spring coil angle as a parameter to simulate the hysteresis characteristics of the twisted coil spring that is a essential factor in the mechanism. A method was also created to use mechanical system analysis tools in order to reduce the labor involved in simulation. The use of these means made it possible to simulate the operating force characteristic curve with an accuracy diverging by no more than 5% from measurement values, with half the labor previously required, and with consideration for the main factors influencing the characteristics. As a result, it has become possible to verify issues including excessive operating force and intermediate stopping at the specification study stage.

The level of rattling noise in the MT drivetrain system is closely related to the state of transmission input shaft rotational speed fluctuation. In this research, the loudness of the noise, which is proportional to the impact of the rattling idle gears caused by the rotational speed fluctuation, and the conspicuousness of the noise, which is caused by the existence of drivetrain resonance, was clearly identified. Furthermore, a drivetrain simulation method for predicting the state of rotational speed fluctuation was developed. In this simulation method, a clutch torsional characteristic defined by the dynamic torsion constant and equivalent damping force coefficient is used as the parameter to improve the accuracy. Consequently, it is now possible to obtain the optimum specification of clutch, the amount of moment inertia and the rigidity of drivetrain torsional characteristic to reduce the rattling noise level at on early stage of the development program.

In general, when an on board battery is low power, the electric power generated from an alternator by a kick-starter operation is consumed by all electrical loads including the battery. This causes a voltage drop. 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 electric power generated by the kick-starter. An electric power control system was incorporated into the ECU. The control system was realized that permits starting of an engine by using the kick-starter even when the battery is completely discharged. Also, by suitable sensing of engine oil temperature, the control system permits an efficient compensation of fuel injection quantity and ignition timing even in an air-cooled engine.

A PVC-free mastic sealer has been developed as a recyclable, environmental friendly material. Core-shell structure type acrylic resin was selected to replace PVC resin for its compatibility with the plasticizer in the formulation. The required mechanical properties could not be achieved by simple replacement of the PVC resin with the equivalent amount of acrylic resin. Therefore, we investigated a change in the synthetic rubber component of the sealer to increase strength. As a result, we found that the addition of an SBR rubber with high tearing strength provided the mastic sealer with high strength and high elasticity properties. The fluidity and contamination properties were improved by changing 42% of the calcium carbonate to a surface-treated calcium carbonate and using an inorganic vulcanization catalyst. This provided the PVC-free mastic sealer with the same performance properties as the conventional mastic sealer. Improving the adhesion to aluminum was required due to the increasing application of aluminum for automobile body panels. We focused on the adhesion performance of the sealer to the aluminum stamping oil in the development. Improved adhesion properties to the aluminum was achieved with a solvent that had a low molecular weight of 170. As a result of the formulation study, we achieved a PVC free mastic sealer of approximately 30% lower in cost than the conventional PVC sealer, which can be used on both aluminum and steel body panels.

The design of automobile packages must generate products which accommodate the diverse body types of vehicle users. The use of digital human model (DHM) technology, which enables designers to freely reproduce different body types on a computer, has recently become more widespread as a means of enabling this. Honda also employs DHM, but has attempted to produce more customer-oriented designs by analyzing driving position in terms of angles of joints and using the results of these analyses as the basis for evaluation of the comfort or discomfort of the driving position. As a result, the position of the DHM can be evaluated in terms of the angles of the joints, providing the foundation of a system in which the development of a package appropriate for a variety of body types can proceed simultaneously with design.

Due to the strong non-linearity and the difficulty of obtaining data on the behavior of polymers at high strain rates, most crash simulations use materials data based on quasi-static testing.

This study therefore attempted to obtain materials data for polymers used in the interior and exterior of automobiles at high strain rates. The material data obtained differs from data obtained through the linear interpolation of stress to model the behavior of polymers at high strain rates. The results of the tests conducted in this project have been compared with results obtained using commercial finite element models.

Modeling Technology for a trimmed body that can predict noise and vibration with short computation time and high accuracy was developed. In order to reduce the total degrees of freedom, parts that exert only a small influence on the acoustic characteristics were simplified from shell elements to concentrated mass models. The acoustic significance of trim parts was determined both experimentally and computationally. Also, Automated Multi-Level Substructuring (AMLS) was applied resulting in significant reduction in computation time. Finally, the trimmed body prediction results agreed closely with experimental data.

Aiming at reducing vehicle pass-by noise, attention was focused on an analysis method employing high-directivity remote noise source locating technology (beamforming method). The beamforming method is a measurement method that uses a combination of multi-channel sensor technology and signal processing technology. It features the ability to measure the overall noise source in a short time and also the ability to provide a visual indication of the noise source distribution. A study of the shape, arrangement and other specifications of the beamforming array for analyzing vehicle pass-by noise was carried out. Based on the results a noise source locating test was performed using both a dummy noise source and an actual vehicle. As a result (1) a noise source locating instrument that had the required locating accuracy and dynamic range was realized, and (2) it was confirmed by using this instrument to analyze vehicle pass-by noise that this method was effective for reducing noise.

Radiation noise in an air cleaner is determined by acoustic excitation due to internal pressure and also by the structural resonance characteristics. A calculation method was developed for predicting radiation noise by acoustic and structural coupling calculation analysis, and also for designing the structure of the air cleaner to be as light as possible. This method was applied to the development of a new air cleaner. As a result, it was verified that the prediction accuracy of the radiation noise was within 300 Hz, which was adequate, and also it was possible to reduce the weight of the air cleaner by 12%, thus proving the effectiveness of this method.

This report describes a verification of cabin noise reduction for a medium class sedan at engine speeds lower than 2 000 rpm. Mode frequencies and mode shapes are defined as a modal arrangement, and a target arrangement is established to achieve significant body response reduction. In order to realize the target arrangement, a FE model of a semi-white body is modified, and an actual vehicle is modified as well. As a result, overall body response is reduced, and a relationship between phases in upper and lower parts of the cabin is improved as aimed. Thus, the modal arrangement is proved to be effective to reduce body noise and vibration.

This paper describes a transfer path analysis method used to analyze the low frequency noise and vibration contribution of suspension and engine mounts caused by second order engine vibration. This transfer path analysis method is capable of removing transmitted forces from other paths (residual forces) besides the main path at a particular degree of freedom. Compared to the conventional methods, results from this analysis method had improved accuracy with respect to vehicle measurements. From the results of the transfer path analysis performed by using this method, frequency range and contribution by the suspension paths for low frequency noise and vibration are clarified.

This paper presents the development of an active control engine mount (ACM) model required to study passive characteristics and control inputs of an ACM, which absorbs increased 1.5 order vibrations caused by three-cylinder operation in a V6 engine. By integrating a dynamic model of the moving parts of an actuator into a conventional hydraulic engine mount model, resonance due to two fluid orifices are expressed. As a result, the ACM model capable of reproducing passive, active and unit characteristics with high accuracy is established. In addition, this actuator force value is obtained with this model to cancel the sub-frame transfer load generated by engine vibrations.

A hybrid SEA modeling method has been developed and applied to increase the accuracy of SEA model for a passenger car. This paper will discuss the detailed workflow of the modeling method and the method employed to verify the accuracy of the model during development. In addition, to provide an example of the high level of accuracy of results, the paper will discuss a road noise (interior cavity sound pressure level.) analysis conducted with a complete vehicle SEA model constructed using the method.

A technique enabling the level of vibration in a suspension to be predicted has been developed to improve road noise performance. Individual parts were defined and modeled to faithfully reproduce their shape and structure, and a method of assembling the parts models was then formulated to enable mid-frequency vibrations to be predicted. In addition, to enable the prediction of vibration in a running suspension, a method of experimental identifying the force transmitted to the suspension by the road surface to initiate vibration was developed. Measured values and predicted values were compared to verify the accuracy of the prediction technique. In addition, the technique was employed to study the reduction of vibration in an actual suspension, confirming its effectiveness in predicting the effects of structural change.

A vibration phenomenon generated in the vertical plane of a motorcycle during high-speed turning has been analyzed using actual running tests and simulation. As a result, it was found that the phenomenon is self-excited vibration caused by the sprung part resonance and the unsprung part resonance of the rear wheel coupled with a frictional force variation in a contact patch of the tire. The simulation model developed reproduced the same vibration phenomenon.

Fluctuation of crankshaft speed in a turbo charged direct-injection diesel (i-CTDi) engine significantly increases the load on the transmission chain.

A simulation method which enables the load on the chain caused by these fluctuations to be predicted was therefore developed. All moving parts, centering on the crankshaft, have been connected in the simulation, which is therefore able to faithfully reproduce a working engine on computer. The model was simplified by focusing on the frequency response of each component when it was being constructed, enabling accuracy to be reconciled with a reduction in calculation time.

This has enabled the load on the chain in an i-CTDi engine to be both accurately and rapidly predicted. The virtual engine contributed significantly to the optimization of the design of the transmission chain in an actual engine.

The Computational Fluid Dynamics simulation of the flame propagation phenomena in a cylinder is carried out to visualize the combustion condition in small displacement, high-speed 4-stroke motorcycle engine. For verifying the simulation results, steady-state in-cylinder flow, fuel injection behavior, and flame propagation behavior were compared. Each experimental result verify the simulation results well, it is validated that the CFD simulation is one of the effective and useful tools to visualize the inside of the cylinder of the engine. This CFD visualizing technology is applied to study of combustion condition of commercial motorcycle engine, and clarified that the technology is effective to reduce the fuel consumption and expand the lean combustion limit. This technology is applied to development of 4-stroke 50cm³ PGM-FI Engine.

An autocoding system has been developed for use in CAD of control systems. This system conducts simulations of fixed point calculations equivalent to those used in ECU implementation, and autocodes the designed control specifications. The use of this system enables simple formulation of the data accuracy (LSB) and data type required for software coding. In addition to coding software in a Honda format, the system autocodes the label information required in setting parameters and monitoring for vehicle tests. As a result, the autocoded software can be employed in ECU implementation without alteration. Verification of the accuracy of calculations using a coverage check enables ECU malfunctions to be prevented before implementation. This has reduced the time spent in correcting the software, and autocoding has shortened the period to ECU implementation by one-third. A level of performance equivalent to the simulation has been achieved with no malfunctions in a single implementation.

To enhance the accuracy of simulation for mechanical analysis of an assembled crankshaft often used in single cylinder, small displacement engines, it is important to make a detailed model of rolling bearings simulating physical phenomena such as deformation, contact, and damping. A rolling bearing model that permits simulation of three-dimensional contact considering elastic properties was developed, and the analysis accuracy was increased. By applying the rolling bearing model to the mechanical analysis of the assembled crankshaft, the correlation between the crankshaft displacement and the strain during actual engine operation was confirmed. As a result, it was confirmed that the rolling bearing model is practically accurate enough for strength computation in the design stage of the assembled crankshaft system.

A method of estimating the durability of the nickel-metal hydride batteries employed in hybrid electric vehicles based on factors contributing to their deterioration was studied. The factors in battery deterioration are battery temperature, current load and state of charge. Based on the expectation that the formulation of a reaction rate equation employing chemical kinetics would enable the durability of the battery to be estimated, the Eyring equation, which enables consideration of temperature and another stress factor was focused on. The number of stress factors in the equation was increased to study the applicability of current load and state of charge.

It was shown that the values of frequency factors of the various factors in battery deterioration in the equation were the same as those obtained in durability tests. These results confirmed that the modified equation enabled multiple factors to be employed in estimations of battery life. Quantification of each factor in deterioration through the use of this reaction rate equation has enabled the estimation of battery life.