Remote oil level indicator

Claim 1

In a vehicle having an internal combustion engine, and a housing defining a reservoir therein, for a liquid lubricant, the housing having a guide tube fixed thereto and projecting inwardly thereof for communication with said reservoir, said guide tube being adapted to receive a conventional manually removable dipstick for indicating the full and low levels of the lubricant in the reservoir, and a system for remotely determining when the lubricant in the reservoir is at or below said low level, the improvement wherein said system comprises: a sensing tube stationarily positioned within and extending through said guide tube, said sensing tube defining a passage therethrough which terminates in an opening at the lower end of said sensing tube, said lower end being disposed substantially at said low level so that said opening is closed off by the lubricant in the reservoir when the lubricant level is above said low level; elongated conduit means having one end at a remote location and the other end connected to the upper end of said sensing tube; actuator means connected to the one end of said conduit means for rapidly supplying a determined mass of air through said conduit means to said sensing tube; and indicator means for sensing the development of a pressure in said sensing tube due to said opening being closed by said lubricant so as to indicate that the level of lubricant in the reservoir is satisfactory and for sensing lack of said pressure when the lubricant level is low due to said lower end not being closed off by lubricant.

Claim 10

A method of adapting a conventional internal combustion engine for permitting remote sensing of the lubricant level therein, said engine having a conventional housing provided with a dipstick tube fixed thereto and projecting inwardly thereof for communication with the crankcase lubricant reservoir, and a manually removable dipstick mounted on the engine and projecting downwardly through the dipstick tube for contact with the lubricant in the reservoir, the dipstick having an "add" lubricant line thereon, comprising the steps of: removing the dipstick; slidably inserting a sensing tube downwardly through the dipstick tube through a predetermined distance so that the open lower end of the sensing tube is positioned at the same elevation as the "add" line on the dipstick when the latter is positioned within the dipstick tube; attaching the other end of the sensing tube through a one-way check valve to a pressure actuator, with said check valve permitting flow therethrough solely in a direction from said actuator to said engine reservoir; connecting said sensing tube, downstream of said check valve, to a pressure sensor; sensing an "add" lubricant situation by actuating said pressure actuator to supply a mass of air into and through said sensing tube, with said air passing through said sensing tube due to the lower end of said tube being uncovered by lubricant so that the air can pass upwardly into the open upper region of the reservoir, and hence not create any sustained pressure within the system so that the pressure sensor does not indicate any sustained pressure buildup; and sensing an adequate lubricant level by actuating the pressure actuator to supply a mass of air into the system so that the air is trapped in the system due to the lower end of the sensing tube being closed by the lubricant so that the air in the system creates a pressure buildup which is sustained and causes a sustained pressure indication on the pressure sensor.

Claim 11

A method of adapting a conventional internal combustion engine for permitting remote sensing of the lubricant level therein, said engine having a conventional housing provided with a dipstick tube fixed thereto and projecting inwardly thereof for communication with the crankcase lubricant reservoir, and a manually removable dipstick mounted on the engine and projecting downwardly through the dipstick tube for contact with the lubricant in the reservoir, the dipstick having an "add" lubricant line thereon, comprising the steps of: removing the dipstick; slidably inserting a sensing tube downwardly through the dipstick tube through a predetermined distance so that the open lower end of the sensing tube is positioned at the same elevation as the "add" line on the dipstick when the latter is positioned within the dipstick tube; attaching the other end of the sensing tube through a one-way check valve to a pressure actuator, with said check valve permitting flow therethrough solely in a direction from said actuator to said engine reservoir; connecting said sensing tube, downstream of said check valve, to a pressure sensor; sensing an "add" lubricant situation by actuating said pressure actuator to supply a mass of air into and through said sensing tube, with said air passing through said sensing tube due to the lower end of said tube being uncovered by lubricant so that the air can pass upwardly into the open upper region of the reservoir, and hence not create any sustained pressure within the system so that the pressure sensor does not indicate any sustained pressure buildup; and sensing an adequate lubricant level by actuating the pressure actuator to supply a mass of air into the system so that the air is trapped in the system due to the lower end of the sensing tube being closed by the lubricant so that the air in the system creates a pressure buildup which is sustained and causes a sustained pressure indication on the pressure sensor.