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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.

A variable valving system was developed. This system has two cam profiles, one for low speed and one for high speed. A 1.2-litre DOHC experimental engine using this system was made and mounted in the body of a 2-1itre class passenger car. Test results of this car were compared to those of the same car with its original engine. The test car showed better results in every area of driving performance, in mode-fuel-econorny and in noise tests. This paper presents the mechanism, operation and test results of this variable valving system, the 1.2-litre experimental engine and this passenger car. THE PERFORMANCE AND EFFICIENCY of the passenger car gasoline engine have been greatly improved: primarily as a response to exhaust-gas emission regulations and the oil crises. These improvements have been achieved mainly through the development of control technologies to optimize many parameters such as ignition timing and air fuel ratio precisely according to driving conditions.

The purpose of this study is to examine compatibility test procedures proposed in the IHRA Vehicle Compatibility Working Group. Various crash tests were conducted with different vehicle weights and stiffness in our previous study, and each of the compatibility problems, namely mass; stiffness and geometric incompatibility were identified in these tests. In order to improve the compatibility, it is necessary to evaluate and control relevant vehicle characteristics of compatibility in test procedures. According to the IHRA study, relevant aspects for compatibility in frontal impact are: Good structural interaction; Frontal stiffness matching; Maintaining passenger compartment integrity; Control the deceleration time histories of impacting cars.

Research has been conducted on Controlled Auto-Ignition (CAI) engine with natural gas. CAI engine has the potential to be highly efficient and to produce low emissions. CAI engine is potentially applicable to automobile engine. However due to narrow operating range, CAI engine for automobile engine which require various speed and load in real world operation is still remaining at research level. In comparison some natural gas engines for electricity generation only require continuous operation at constant load. There is possibility of efficiency enhancement by CAI combustion which is running same speed at constant load. Since natural gas is primary consisting of methane (CH4), high auto-ignition temperature is required to occur stable auto-ignition. Usually additional intake heat required to keep stable auto-ignition. To keep high compression temperature, single cylinder natural gas engine with high compression ratio (CR=26) was constructed.

This study examined a high-speed, high-powered diesel engine featuring a pent-roof combustion chamber and straight ports, with the objective of improving the specific power of the engine while minimizing any increase in the maximum cylinder pressure (Pmax). The market and contemporary society expect improvements in the driving performance of diesel-powered automobiles, and increased specific power so that engine displacement can be reduced, which will lessen CO2 emissions. When specific power is increased through conventional methods accompanied with a considerable increase in Pmax, the engine weight is increased and friction worsens. Therefore, the authors examined new technologies that would allow to minimize any increase in Pmax by raising the rated speed from the 4000 rpm of the baseline engine to 5000 rpm, while maintaining the BMEP of the baseline engine.

Devices for use in control of exhaust emissions have become indispensable to motorcycles. In order to evaluate quantitatively the effect of each device, the modal analysis system has to be required. The Modal Analysis System is one that classifies any driving schedule which is used for emissions measurement into four modes: idle, acceleration, cruise, and deceleration; then measures the emissions continuously using a mini-computer which accumulates the results of the analysis by mode. Instead of CO2 tracer method, we introduced the method of diluted exhaust gas measurement. In order for the system to produce reliable measurements, the accuracy of the total installation must be ensured. This paper describes the improvements of accuracy of analysers, technique on handling delay time and the verifications on the modal analysis system.

Operational analysis of automotive engines using flexible multi-body dynamics is increasingly important from the viewpoint of multi-objective optimization as it can predict not only vibration, but also stress and friction at the same time. Still, the finite element (FE) models used in this analysis have large degrees-of-freedom, so iterative calculation takes a lot of time when there is form change. This research therefore describes a technique that applies a modal differential substructure method (a technique that reduces the degrees of freedom in a FE model) that can simulate form changes in FE models by changing modal mass and modal stiffness in reduced models. By using this method, non-parametric form change in FE model can be parametrically simulated, so it is possible to speed up repeated vibration calculations. In the proposed method, FE model is finely divided for each form change design area, and a reduced model of that divided structure is created.

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.

When the belt contacts a pulley in a pushing belt-type CVT, vibration is generated by frictional force due to rubbing between the individual elements that are components of the belt, which is said to increase wear and noise. The authors speculated that the source of that vibration is misalignment of the secondary pulley and primary pulley V-surfaces. To verify that phenomenon, a newly developed micro data logger was attached to an element of a mass-produced metal pushing V-belt CVT and the acceleration was measured at rotations equal to those at drive (1000 to 2500 r/m). In addition, the results of calculations using a behavior analysis model showed that changes in pulley misalignment influence element vibration, and that the magnitude of the vibration is correlated to the change in the metal pushing V-belt alignment immediately before the element contacts the pulley.

In engines having an inline four cylinder DOHC configuration, the rotational vibrations of camshaft increase at high engine speeds above 10000 rpm, causing an increase of tension in the cam chain. It is therefore difficult to realize an optimum designing of a cam chain system when the durability has to be taken into considerations. Using the simulation we analyzed in this research how the rotational vibrations and tension increase at high engine speeds in an inline four cylinder DOHC engine. As its consequent, it is understood that the increases of rotational vibrations and tension caused by the resonance of the spring mass vibration system in which the cam chain serves as springs and the camshafts as the equivalent masses. Also it is found out that the vibration system is of a unique non-linear type in which the resonance of the fourth order frequency is also excited by the crankshaft torque fluctuations of the second order frequency.

This paper describes the evaluation of flow characteristics inside a model engine cylinder using particle image velocimetry (PIV), laser Doppler anemometry (LDA), and numerical simulation by Partial Cells in Cartesian coordinate (PCC) method. The main goal of the study is to clarify the differences in the velocity characteristics obtained by these methods. The model engine head has a four-valve system. Single- and dual- valve opening conditions of the model engine head were tested by a steady flow test rig. The flow structures were completely different for these valve opening conditions. The mean velocities and their distributions obtained by the three methods show satisfactory agreement. However, there were differences in the turbulence intensities under several conditions and measuring positions. Taylor's hypothesis in the integral length scale of turbulence was also compared with single LDA and PIV measurements.

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.

This study aims to build a conceptual simulation used at the early stage of PHEV development. This simulation enables to design vehicle concept and fundamental architecture with regard to fuel economy, vehicle acceleration and electric range. The model based on forward-looking method comprises of plant-model and controller-model which are made by one-dimensional simulation tool “GT-SUITE” and Matlab/SIMULINK respectively. In order to automatically couple between them and to implement iterative calculations of SOC (State-of-Charge) convergence, optimization and automation tool “modeFRONTIER” was used. As a case study of this simulation, we adopted series-parallel type plug-in hybrid electric vehicle (PHEV) and demonstrated the results on fuel economy of a legislative driving cycle and 0-60mph vehicle acceleration. Moreover, procedures to identify component specifications meeting vehicle targets and requirements at the early stage of vehicle development were concretely described.

The suitability of FM radio receivers for automobiles has conventionally been rated by evaluating reception characteristics for broadcast waves in repeated driving tests in specific test environments. The evaluation of sound quality has relied on the auditory judgment due to difficulties to conduct quantitative evaluations by experiments. Thus the method had issues in terms of the reproducibility and objectivity of the evaluations. To address these issues, a two-stage method generating a virtual radio wave environment on a PC was developed. The research further defined the multipath distortion rate, MDr, as an index for the sound quality evaluation of FM receivers, and the findings concerning the suitability of the evaluation of FM terminals for automobiles were reported at the 2015 SAE World Congress.

There are a couple of ways to manufacture aluminum cylinder blocks that have a good balance between productivity and abrasion resistance. One of them is the insert-molding of a sleeve made of PMC (Powder Metal Composite) by the HPDC (High Pressure Die Casting) method. However, in this method, cracks are apt to occur on the surface when the PMC sleeve is extruded and that has been a restriction factor against higher extrusion speed. The authors attempted to raise this extrusion temperature by eliminating the Cu additive process from the aluminum alloy powder in order to raise its melting point by approximately 50 °C. This enabled the wall of the extruded sleeve to be thinner and the extrusion speed to be higher compared to those of a conventional production method while avoiding the occurrence of surface cracks.

There are several all-aluminum cylinder blocks. A typical example is a mono-block cylinder of alusil alloy produced by low pressure die casting. This material's resistance to abrasion and seizure, however, is not satisfactory for motorcycle; in addition, long processing time is another disadvantage. To cope with these problems, the authors developed a light and highly productive all-aluminum cylinder block with a cast-in liner through die casting. The liner is made from powder metallurgy composite (PMC) with 3 to 5 % alumina and 0.5 to 3 % of graphite additives. The PMC reconciles abrasion resistance and machinability. The hardness deterioration of the composite due to the heat at die casting is avoided by using heat-resistant rapidly-solidified powders, made from an aluminum-silecon-iron alloy, for the matrix.

Honda developed a 750cm3 V-4 engine adopting an elliptical piston, and began selling the “NR” motorcycle with the engine installed in 1992. The adoption of an elliptical piston and cylinder achieved a compact layout of eight valves, which consists of four intake valves and four exhaust valves per cylinder. This paper explains the features of an engine with such a layout, focusing on the following: 1) Multiple valves and short-stroke enable the 750cm3 engine to achieve 15,000rpm. 2) The engine is more compact and lightweight than an engine having the same displacement, and more powerful than one with twice as many cylinders (8 cylinders). Also, this paper describes the techniques giving improved blowby gas and oil consumption characteristics as related to the sealing property of the piston, cylinder and piston ring and achieving performance equivalent to a conventional motorcycle engine.

With a growing demand for high-power diesel engines, a key issue in engine development is to create efficient methods for developing highly durable cylinder heads, without having to repeat trial-and-error testing. Especially, it was difficult to accurately predict the occurrence and origin of cracks on the surfaces of cylinder heads in hot and cold cycle engine operation. This paper describes a thermal fatigue evaluation method developed by analyzing areas around the glow plug hole where cracks often occur during hot and cold cycle engine operation. To reveal the conditions of edges from which cracks were formed under engine durability tests, we used two procedures. One was estimating local temperature of edge areas based on material hardness determination, in order to compensate for the accuracy of the thermal analysis. The other was analyzing the strain amplitudes on the cylinder head surface using computer simulation.

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.

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.