Terumi Nakazawa

Highly reliable silicon micromachined physical sensors in mass production

Abstract Silicon micromachined physical sensors such as silicon pressure sensors and accelerometers are now in mass production in response to the strong market demands. In the design of such sensors, it is most important to guarantee high reliability as well as low cost. To respond to these demands for microsensors, the designs of device structure, production processes and packaging have been investigated in detail.

Multiplex in-cylinder pressure measurement utilizing an optical fiber with specific refractive-index composition

An approach to multiplex in-cylinder pressure measurement that utilizes a single-mode optical fiber with specific refractive-index composition has been proposed. The sensing fiber has been designed to show a certain amount of optical power loss with a small change in the fiber-local-bend radius. Along with pressure-transferring diaphragms the sensing fiber was embedded into the head gasket of a four-cylinder gasoline engine. The internal-pressure change in each combustion chamber was detected on the basis of bending power loss in the fiber. Combustion pressure peaks for each cylinder were clearly observed.