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The goal of this research was to improve thermal efficiency under conditions of stoichiometric air-fuel ratio and 91 RON (Research Octane Number) gasoline fuel. Increasing compression ratio and dilution are effective means to increase the thermal efficiency of gasoline engines. Increased compression ratio is associated with issues such as slow combustion, increased cooling loss, and engine knocking. Against these challenges, a higher stroke-bore ratio (S/B ratio) and a lower effective compression ratio were tried as countermeasures. With respect to increased dilution, combustion of a high-EGR (Exhaust Gas Recirculation) was tried. High-energy ignition and optimized combustion chamber shape with high tumble port were tried as countermeasures against slow combustion and reduced ignitability due to a higher EGR rate.

In this paper, the advanced damage analysis of composite materials and structures made of continuous fibers embedded in a polymer matrix is addressed. The solution is based on the LMS Samtech Samcef finite element code, from Siemens PLM Software, which is now available in the Siemens NX CAE environment, with the specific focus of solving non-linear analysis problems for composites. Globally speaking, LMS Samtech Samcef is an implicit non-linear solver able to solve quasi-static and dynamic problems, with a comprehensive library of structural elements and kinematic joints. First, the sizing strategy based on the building block approach (pyramid of physical and virtual tests) is recalled. Applied for years in the aerospace industry, it is here extended to the automotive context. In this approach, the knowledge on the composite material and structure is built step by step from the coupon level up to the final full scale structure.

Using a 1D simulation that transforms the 3D shape of intake-exhaust systems into one dimension and calculates the thermodynamics and fluid gas dynamics of internal combustion engines, a prediction technology of the output power and intake-exhaust noise for small- displacement single-cylinder motorcycles was established. Output power can be calculated accurately for various engines with different displacements and cooling systems by adjusting the boundary conditions in the calculation model. The intake-exhaust noise can be calculated accurately by clarifying some important points for accuracy when transforming the 3D shapes of the intake-exhaust system into the 1D model and by reflecting them in the calculation model. As for mufflers that have complicated internal structures, the calculation of exhaust-noise cannot be made with sufficient accuracy because 1D simulation does not calculate spatial flow behavior. But, improvement of accuracy is expected using a 1D-3D coupled simulation.

Although spark-ignited engines have a considerable development history, the relevant flow physics and geometry design implications are still not fully understood. One reason is the lack of experimental and numerical methods with sufficiently high resolution or capabilities of capturing stochastic phenomena which could be used as part of the development cycle. More recently, Large-Eddy simulation (LES) has been identified as a promising technique to establish a better understanding of in-cylinder flow variations. However, simulations of engine configurations are challenging due to resolution as well as modeling requirements and computational cost for these unsteady multi-physics problems. LES on full engine geometries can even be prohibitively expensive. For this reason, the size of the computational LES domain is here reduced to the region of physical interest and boundary conditions are obtained from a RANS simulation of the whole experimental flow domain.

This paper reports on the interim progress of the Honda-DRI ACAT-II program initiated by the National Highway Traffic Safety Administration (NHTSA). The objectives of the ACAT-II program were further development of a formalized Safety Impact Methodology (SIM) for estimating the capability of advanced technology applications installed in vehicles to address specific types of motor vehicle crashes, and to evaluate driver acceptance of the technologies. This particular ACAT study extended earlier work by Honda and DRI in the NHTSA ACAT-I program by extending the SIM so as to be able to analyze head-on crashes more completely, and by using the extended SIM to evaluate of a pre-production version of a Honda Head-on Crash Avoidance Assist System (HCAAS).

In motorcycle engines with aluminum crankcases, fatigue fractures at the roots of the internal threads of the fastening bolts used for the cylinder head and crankshaft main bearing often occurs during the durability tests at the prototype stage. A technology that evaluates the fatigue strength of the entire crankcase including the roots of internal threads using a large-scale and nonlinear finite element method (FEM) analysis is established by this research. Parallel process computation by a cluster server enables the evaluation of the fatigue strength of the crankcase in a short time suitable for the development process even when using a model that faithfully reproduces the shape, the contact property, and the elasto-plastic material characteristic of the threads. This technology enables the efficient design of crankcases that are light and durable.

The SAE Fuel Cell Vehicle (FCV) Safety Working Group has been addressing FCV safety for over 11 years. In the past couple of years, significant attention has been directed toward a revision to the standard for vehicular hydrogen systems, SAE J2579(1). In addition to streamlining test methodologies for verification of Compressed Hydrogen Storage Systems (CHSSs) as discussed last year,(2) the working group has been considering the effect of vehicle fires, with the major focus on a small or localized fire that could damage the container in the CHSS and allow a burst before the Pressure Relief Device (PRD) can activate and safely vent the compressed hydrogen stored from the container.

In order to simulate the valve behavior of an engine that uses a hydraulic lash adjuster (HLA), it is necessary to accurately reproduce the dynamic characteristics of the HLA in the model. Formerly, the model used values from drawings and values based on past experiences, and did not reflect actual driving conditions such as oil properties, leaked oil quantity, or oil aeration rate. We therefore developed a technique to reproduce HLA unit dynamic characteristics in a high-accuracy simulation. This representation was made possible using a unit excitation test to quantify the HLA unit dynamic characteristics in four categories: HLA stiffness, load response delay of the plunger, sinking displacement after relaxation, and lissajous curve of load vs. displacement. The effectiveness of this model calibration technique was confirmed through comparison of unit dynamic characteristics in a unit excitation test and a calibrated simulation.

The world's first Variable Cylinder Management (VCM) system for large motorcycles, which will achieve both high power and low fuel consumption, has been developed. The system uses a mass production in-line four-cylinder engine which has a displacement of 1137 cm₃ as the base engine. The VCM system is capable of increasing and decreasing the number of working cylinders between 2-cylinder, 3-cylinder and 4-cylinder operations by modifying some parts of the base engine. Utilizing throttle valves installed on each cylinder, the throttle valves for continuously operating the regularly working cylinders and the on-demand working cylinders are controlled by three motors, which divide them into three independent lines. In order to improve fuel consumption by reducing the pumping loss of the non-working cylinders, the engine is equipped with hydraulically operated intake and exhaust valve deactivating mechanisms.