Abstract: A fluid level measuring system for machines which utilizes fluids and has rotating and/or reciprocating elements. The system receives data from sensors as to the measured fluid level and measured fluid temperature. Optionally, data is received from other sensors such as to the angle of inclination of the machine, gear setting (for a transmission), idle speed (for an engine or transmission), and dielectric constant of the fluid. The measured data is stored in a first data storage device. A second data storage device contains data as to the recommended fluid level and acceptable deviations thereof based upon a variety of possible sensor readings, which can be obtained from sources such as the manufacturer of the machine or by controlled dynamic measurements. A processor compares the stored sensor readings to the data stored in the second memory to arrive at the operational fluid level. The processor controls a display to identify the operational fluid level to the operator.

Abstract: Method and apparatus for automatically changing engine lubricating oil while the engine is running, in which small increments of used lubricating oil are periodically removed from the lubricating oil system, and substantially simultaneously with the removal of each increment of used oil, a corresponding increment of fresh oil is delivered to the lubricating oil system, so the volume of oil in the lubricating system is not reduced by the removal. Oil sump level sensing determines the destination of each used oil increment that is removed. If the sump level is not substantially below a predetermined satisfactory operating level when an increment of used oil is removed, the increment is delivered to the fuel tank for burnoff with the fuel for diesel engines, or to a holding tank for other engines, in a normal oil change mode of operation.