Apparatus for measuring the mass of a flowing medium

US4304128A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Udo Hafner · Munich, DE
• Peter Romann · Stuttgart, DE

Key dates

• Filing date: Oct 11, 1979
• Grant date: Dec 8, 1981
• Expiry date: Oct 11, 1999

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F1/698
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An apparatus is proposed for measuring the mass of a flowing medium, and in particular for measuring the air mass of internal combustion engines. The apparatus includes a resistor arranged in the stream of the flowing medium, the temperature and/or resistance parameter of this resistor being controlled in dependence on the mass of the medium, the extent to which the parameter is controlled being a measure of the mass of the flowing medium. The resistor is an element of a bridge circuit comprising at least one further resistor arranged in the stream of the flowing medium. Also included is a tubular member which has an inner surface defining the flow cross section of the flowing medium. Within this tubular member there is situated a probe ring to which both resistors are mounted to be exposed to the flowing medium. Connected to the tubular member is a terminal box within which a hybrid switching circuit is situated. The hybrid switching circuit is mounted to a mounting board and is connected, by a printed circuit board, to a multiple contact plug and to the bridge circuit.