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A new method for measuring unregulated substances in the exhaust gas is being investigated to clarify the influence of the vehicles' exhaust emissions into the environment. This paper explains our work on developing an analysis method for detecting and quantifying trace substances in the exhaust gas. A new analysis method was examined that uses thermal desorption to analyze trace amounts of polycyclic aromatic hydrocarbons (PAHs) in vehicle exhaust gas. This technique is faster than conventional methods and does not require any preconditioning of the samples before analysis. While lead and chloromethane were detected in the exhaust gas samples, it was made clear that these substances did not originate in the engine system. Accordingly, the results of this study indicate that careful attention must be paid to the test environment and the presence of measurement interfering substances in exhaust samples when measuring trace constituents in the exhaust gas from low-emission vehicles.

YAMAHA Motor has developed and marketed a hybrid bicycle with an electric supplemental power source which generates assist power in proportion to the pedal torque by riders. The key function required for this assist power control system is that the variation of the assist ratio should be as small as possible over wide range of riding conditions. The assist power control system consists of mechanical and electrical components and requires a very tight quality control of each component if the design fails to be robust to disturbances such as pedal torque or vehicle speed. We applied the Taguchi method to this development and succeeded in selecting the optimum combination of component levels in the system.