Oil level detector

TL;DR: In this article, an oil level sensing device is provided for use in conjunction with an engine having a cycling vacuum source, an oil reservoir and a dip stick guide tube extending upwardly from the oil reservoir.

Abstract: An oil level sensing device is provided for use in conjunction with an engine having a cycling vacuum source, an oil reservoir and a dip stick guide tube extending upwardly from the oil reservoir. The device comprises a housing defining a chamber while a valve plate having a port divides the housing chamber into upper and lower chambers. An elongated fluid conduit is secured to the housing and open to the lower chamber while the other end of the conduit is insertable into the dip stick guide tube and the end of conduit is positioned at a predetermined level with respect to the oil reservoir. A piston is slidably mounted within the upper chamber and is movable between an upper and a lower position. A spring urges the piston towards its lower position during low vacuum mode while the engine vacuum source, connected to the upper chamber, urges the piston towards its upper position during high vacuum mode. A float valve is contained within the lower chamber for closing the port in the valve plate only when the oil within the reservoir is above a predetermined level thus limiting the upward movement of the piston. When the oil is below a predetermined level, there is insufficient oil drawn into the float chamber to close the float valve and the piston is thereby free to travel to the top of the upper chamber. The piston actuates an electrical switch when in its uppermost position which, in turn, actuates an alarm.