摘要 |
In an apparatus for measuring the velocity of flow of fluids, and particularly the intake air of internal combustion engines, with an electrically heatable resistance layer which is applied in insulated manner onto a support, and is in thermal contact with the flowing fluid, a layer of low thermal conductivity is furthermore applied in such a manner that the local heat transfer coefficient between the flowing fluid and the resistance layer is at least approximately constant in the direction of flow. In this connection, the thickness of the layer can decrease continuously or stepwise in the direction of flow. A reduction in the response time is obtained. Glass or polytetrafluorethylene, among other substances, enter into consideration as material for the layer. |