| 摘要 |
PURPOSE:To detect a fuel injection timing by cuasing the change in magnetic flux density of a magnetostrictive material with the aid of exciting coil, to stabilize detection, and to improve precision, by forming at least a part of a passage wall, through which injection fuel flows, by the use of the magnetostrictive material. CONSTITUTION:A part of a fuel injection pipe is formed by a pipe 11 of a magnetostrictive material which consists of a magnetic material, such as iron, nickel, or an alloy of them, and is of a material of which permeability varies according to stress strain. A bobbin 12, made of an insulating material such as plastic, is disposed on the outer periphery of the pipe 11, and an exciting coil 14 and a detecting coil 15, which are connected to an a.c. power source 13, are wound around the bobbin 12. This forms a magnetic circuit at the pipe 11, and an induction electromotive force is excited at the coil 15. The produced output voltage of the coil 15 is processed by an appropriate electric processing means P, resulting in the ability to find a fuel injection timing. |
