Apparatus for detecting fuel mixture ratio

摘要

A prism has at least two optical planes and one of the planes is a boundary plane with mixed fuel. On one of two planes, a light emitting element is mounted and illuminates light to the boundary plane through the prism. A light receiving element receives light reflected from the boundary plane and converts the reflected light into electrical signals. Then a detector modifies the electrical signals from the light emitting element according to the detecting result and outputs them as detecting signals representative of the fuel mixture ratio. The temperature of the mixed fuel may be detected by a temperature sensor in which case the electrical signals are also modified to compensate for temperature changes of the mixed fuel.