Abstract: System for radio transmission of level data of liquid contained in a tank and for converting to the level data to volume data to be indicated. A transmitter includes a cell for supplying electric power, a microcomputer connected to the cell and normally dept in a standby state in which it consumes a small amount of electric power. A timer is connected to the cell and the microcomputer to provide the latter with activation signals to place it in a activated state at a predetermined interval. A level detector if supplied with electric power from the cell only when the microcomputer is activated to provide the level data. A memory is continuously supplied with the electric power from the cell to memorize the level data, and a modulator supplied with the electric power from the cell only when the microcomputer is activated to transmit the level data in the memory by carrier waves through an antenna, whereby the system saves power consumption of the cell.

Abstract: Apparatus for exchanging waste oil with fresh oil in a device such as torque converter, based on a new finding that extracting waste oil from the pan thereof, supplying fresh oil thereinto and after the lapse of some pause time such extract and supply are repeated during said torque converter is kept to operate to circulate oil between the converter proper and the oil pan. The repetition of extract, supply and pause is automatically done according to the operation design stored in the computer with determining the total amount of extracted waste oil and fresh oil to be supplied.

Abstract: An apparatus for measuring the quantity of a liquid such as a fuel in a tank, which comprises liquid level measuring electrodes, comparing electrodes dipped always in the liquid to detect the capacitance inherent to the liquid, an LC oscillator for converting each capacitive value measured by the electrodes into a corresponding frequency signal, reference electrodes constituting a level feeder together with the oscillator to compensate for capacitive variation of the latter, and a microcomputer for calculating a liquid quantity in the tank based on the frequency signals and for displaying the calculated quantity.