The invention and the power input is, in the circuit for sensing the flow and temperature of the piston cooling oil, a voltage of 24v output, and the constant voltage portion for changing and maintaining the voltage output from the power input to a constant voltage, in the constant voltage section and the resistance value is detected using a platinum resistance temperature sensor which is driven with an input voltage (PT100 sensor), the line resistance and the Wheatstone in order to compensate the change of the resistor according to the distance (wheatstone) but using a bridge (bridge) method , and wherein the variation value of the resistance was amplified through the operational amplifiers accepting a temperature sensing unit, and the temperature converting unit changes a value of the temperature voltage through a detection is digitized through the converter (convertor) to be outputted to a temperature display, the It flows in the voltage input from the power input sensor (flow sensor), and the drive consists of a sensing unit consisting of fluid flow structure that is lit on the indicator lamp or absence of fluid flow.
As described above, since the state detection circuit and the device of the piston cooling oil for marine engines according to the present invention is projected to the inner surface of platinum resistance temperature sensor (PT100 sensor) and the flow sensor housing, the space efficiency improved and convenient installation structure it is easy to decompose any trouble occurs, bonds, temperature display and fluid flow indicator lamp is the value measured at the platinum resistance temperature sensor (PT100 sensor) and flow sensor being displayed with each digitized on the body top surface yet capable of controlling after that the user to quickly there are other effects.