Test system for electro magnetic fuel injector valves - checks current peaks for a given time to determine if valve needle has moved

摘要

The injector to be tested need not be removed from the engine and may be operated by unskilled persons. A working voltage is applied to the injector coil and the current flows to a switch and a precision resistor. The resulting signal passes on one side to a differentiator which determines if by a current increase through the injector coil surges are occuring. The output signals are fed to a threshold value switch connected to the first input of an AND-gate. Should no corresponding signal enter from a delay unit the AND-gate becomes conductive and a display unit gives a signal indicating that the injector is satisfactory.