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This paper reviews and summarizes the history of motorcycle leg protection research. This consists of a summary of the devices and concepts, as well as a description of the evolving methodology used to evaluate such devices. For over two decades members of the Japan Automobile Manufacturers Association (JAMA) along with other organizations worldwide have studied motorcycle leg protection devices toward the goal of minimizing motorcyclists' leg injuries occurring during collisions. In the early phases of this research, it was found that maintaining leg protection space during collision was possible by using certain kinds of leg protection structures. At the same time, it was also found that such devices have the potential to worsen overall rider injuries, including increased head injuries, due to effects such as rider ejection and torso pitch.

It has been widely reported that injury to the leg is the most common form of non-fatal trauma associated with motorcycle accidents. Furthermore, it has also been reported that the majority of motorcycle leg injuries resemble those experienced by pedestrians in that they do not involve crush. Rather, these injuries appear to involve only a direct impact between the leg and an opposing rigid object. Often the soft tissue of the limb is injured from the inside out in that sharp bone fragments and jagged ends lacerate the soft tissue as relative motion occurs. The complexity of understanding these results is due to a combination of impact effects, biological material properties and human geometric considerations. Our ongoing research, underway for several years, is providing the fundamental data for cadaver leg and bone impact response.

A hot-wire air flow sensor which can directly measure the intake air mass flow has been developed, and a microprocessor based engine control system using the sensor has been designed. The sensing probe of the sensor is formed from a small wire-wound resistor, and installed in the bypass of the intake passage. The sensor requires a good signal processing method under pulsating flow conditions because of its quick response. New control technologies were examined for the prototype engine control system, using the sensor, as applied to a 4 cycle, 4 cylinder engine. The air-to-fuel ratio, ignition timing, and EGR rate are controlled to their optimum values by a microprocessor which processes signals of this sensor and of other sensors indicating the engine operating conditions. The results of engine performance tests show that the output power, fuel economy and exhaust emissions are improved significantly in comparison with other fuel management systems.