US 7,613,582 B2 · Thermal type flow rate measurement apparatus

Abstract

Thermal type flow rate meters for measuring the flow rate of intake air of an internal combustion engine of a motor vehicle or the like have encountered a problem of an increase in pulsation errors during high engine speed and high pulsation. Meanwhile, digitally recovering responses has posed a problem in which pulsation performance is liable to become worse, affected by variation in a clock or the like. The sensor is provided with means for transferring a response variation factor to the engine control unit. The engine control unit is provided with logics for automatically determining the variation factor and correcting a response. Means for detecting a backflow occurrence is provided and a parameter for a response recovery is changed before and after a backflow occurrence. The sensor is provided with a selecting means by which a sensor response can be selected and obtained and the engine control unit is provided means for allowing selection of a response.

Claims15

Dependent claims

A thermal type flow rate measurement apparatus comprising a flow rate sensing element for sensing a flow rate of a fluid and capable of also sensing a forward flow and a backflow of a pulsating flow in said fluid, characterized by comprising:

a response recovery means for recovering a response delay of an output signal from said flow rate sensing element;
and
a means for determining whether or not to execute a response recovery for said output signal or changing a parameter value for said response recovery, in accordance with a determination as to whether a backflow occurs or an estimated amount of said backflow.

Dependencies are inferred from the claim text.

Thermal type flow rate measurement apparatus

Life of this patent

Thermal type flow rate measurement apparatus

Life of this patent

Abstract

Claims15