Method of measuring level of filling
US5272919A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 2, 1992 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Apr 2, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F23/246
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for measuring the level of filling, such as the level of oil in an automotive engine, employs a hot-wire measuring device in which a hot-wire transmitter (5) is charged with a predetermined constant current, and an increase in voltage over the hot-wire transmitter is detected within a predetermined period of time. Errors due to digitizing and inaccurate calibration are avoided by the simplest possible means. For this purpose, a current source (1), which is controlled by an input voltage, is used as a source of the constant current. Furthermore, in a preparatory stage, after an assembly of the hot-wire measuring device, an input voltage (PWM) is changed until, at an input-voltage value wherein the current source (1) produces the predetermined constant current (IK). The input-voltage value is used in subsequent measuring stages to control the source of current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.