Flow measuring device

Patent metadata

Field	Value
Publication number	US-2016356231-A1
Application number	US-201615164006-A
Country	US
Kind code	A1
Filing date	May 25, 2016
Priority date	Jun 2, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A flow measuring device includes an output portion that outputs an electric signal having a shape of rectangle wave with an edge rising or falling in a signal value. The electric signal corresponds to a flow rate of intake air drawn into an internal-combustion engine. The output portion applies or stops a control voltage to a switching element disposed in an output wiring through which the electric signal is output so as to form the edge. The output portion has an edge relief part that changes the control voltage with progress of time so as to gradually increase or decrease the signal value at the edge.

First claim

What is claimed is:

1 . A flow measuring device comprising:
an output portion that outputs an electric signal having a shape of rectangle wave with an edge rising or falling in a signal value, the electric signal corresponding to a flow rate of intake air drawn into an internal-combustion engine, wherein the output portion applies or stops a control voltage to a switching element disposed in an output wiring through which the electric signal is output so as to form the edge; and an edge relief part that changes the control voltage with progress of time so as to gradually increase or decrease the signal value at the edge.

2 . The flow measuring device according to claim 1 , wherein
the edge relief part has
a pattern instruction part that memorizes a pattern in which the signal value is changed at the edge and that outputs a plurality of instruction values as time series data which defines the pattern one by one according to progress of time, and
a control voltage output unit that changes and outputs the control voltage with progress of time according to the instruction values outputted from the pattern instruction part.

3 . The flow measuring device according to claim 2 , wherein
the switching element configures a current mirror circuit, and the control voltage output unit applies the control voltage to the switching element through the current mirror circuit.

4 . The flow measuring device according to claim 1 , further comprising:
a capacity element connected in parallel with the switching element.

5 . The flow measuring device according to claim 1 , further comprising:
a second switching element connected in series of the switching element on a high potential side of the switching element, wherein the second switching element has a withstand voltage that is higher than that of the switching element.

6 . The flow measuring device according to claim 1 , further comprising:
a Zener diode connected in parallel with the switching element.

7 . A flow measuring device comprising:
an output portion that outputs an electric signal having a shape of rectangle wave with an edge rising or falling in a signal value, the electric signal corresponding to a flow rate of intake air drawn into an internal-combustion engine; a switch circuit in which a plurality of switching elements are connected in parallel, the switch circuit being a part of an output wiring for outputting the electric signal, a control voltage being applied or stopped relative to at least one of the switching elements when the edge is formed; and an edge relief part that changes the number of the switching elements to which the control voltage is applied or stopped with progress of time so as to gradually increase or decrease the signal value at the edge.

8 . The flow measuring device according to claim 7 , wherein
the edge relief part has
a pattern instruction part that memorizes a pattern in which the signal value is changed at the edge and that outputs a plurality of instruction values as time series data which defines the pattern one by one according to progress of time, and
a control voltage output unit that outputs the control voltage and that changes the number of the switching elements to which the control voltage is applied or stopped with progress of time according to the instruction values outputted from the pattern instruction part.

9 . The flow measuring device according to claim 7 , wherein
the switch circuit has a sub switching element connected in series of each of the switching elements on a high potential side of the switching element, and the sub switching element configures a current mirror circuit.

10 . The flow measuring device according to claim 7 , further comprising:
a capacity element connected in parallel with the switch circuit.

11 . The flow measuring device according to claim 7 , further comprising:
a second switching element connected in series of each of the switching elements on a high potential side of the switching element, wherein the second switching element has a withstand voltage that is higher than that of the switching element.

12 . The flow measuring device according to claim 7 , further comprising:
a Zener diode connected in parallel with the switch circuit.

13 . The flow measuring device according to claim 1 , wherein the output portion outputs the electric signal according to a physical quantity of intake air other than the flow rate.

14 . The flow measuring device according to claim 13 , wherein the physical quantity is at least one of pressure, humidity, and temperature.

Assignees

• Denso Corp

Inventors

• Enomoto Takashi

Classifications

• F02D41/182 Primary

  for the control of a fuel injection device · CPC title

• G01F1/696 Primary

  Circuits therefor, e.g. constant-current flow meters · CPC title

• F02D41/18

  by measuring intake air flow · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title