Hot film/swirl fluid flowmeter
US4449401A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1981 |
| Grant date | May 22, 1984 |
| Priority date | — |
| Expiry date | May 19, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F15/022
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A low pressure drop hot film/swirl air flowmeter (10) for an automotive engine is disclosed. The flowmeter includes a main air flow passage (18), a relatively small venturi (20) disposed within the passage for receiving a portion of the air flow, a constant temperature thermal anemometer (48) positioned to sense the air flowing in the throat (44) of the venturi, and a set of swirl vanes (22) operative to impart a swirl to the remainder of the air in the main passage, thereby creating a reduced pressure at the venturi outlet for forced aspiration therethrough without appreciably increasing the pressure drop across the flowmeter. The anemometer includes a bridge circuit (114), one leg of which comprises a resistive sensor (70) within the throat of the venturi. In the preferred embodiment of the invention, an ambient air temperature sensor (72) is included as another of the legs of the bridge to provide temperature compensation for the flowmeter. The anemometer generates an output signal representative of total mass air flow through the flowmeter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.