An Injecting Pulse Valve With a Low Cost Micro Volume Measuring Device Featuring Linear Properties

In this work the volumetric measurement of an injecting pulse valve is considered. Such injectors can use a highly pressurized fluid with varying pressure ranges thus making the injection time variable. One important point of such a measuring system is that it should be as simple and as cheap as possible considering economic reasons but at the same time there is a high demand in regard to the measuring accuracy. Electronics taking into account all those requirements have been developed using a permanent magnet which is floating inside a tube. A coil surrounding the fluid passing tube at the outside is measuring the induced voltage of the moving magnet inside. With the use of an additional capacitance the stroke of the permanent magnet can be very precisely determined. The lower part of the capacitance’s charge curve is used which emulates an integrating device. Thus, it is possible that although the electronics is cheap and small in size the measurement function is behaving linear, independently of the pressure. Finally, a micro processor measures the induced voltage and thus evaluates the volume of the injected fluid.