WO1998011408A1 - Debimetre d'air thermique - Google Patents
Debimetre d'air thermique Download PDFInfo
- Publication number
- WO1998011408A1 WO1998011408A1 PCT/JP1996/002628 JP9602628W WO9811408A1 WO 1998011408 A1 WO1998011408 A1 WO 1998011408A1 JP 9602628 W JP9602628 W JP 9602628W WO 9811408 A1 WO9811408 A1 WO 9811408A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- air flow
- analog
- digital conversion
- conversion means
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
Definitions
- the present invention relates to a thermal air flow meter, and more particularly, to an intake air flow meter for measuring the amount of air flowing into an internal combustion engine.
- JP-A-2-85724 As a method of detecting the amount of air taken into the internal combustion engine, converting the air flow rate signal from analog to digital, and converting the analog to digital, there is, for example, JP-A-2-85724. These are composed of a bridge circuit for detecting an air flow rate, an air flow rate detection device including a detection circuit, and an electronic control device having a circuit for digitally converting the air flow rate signal.
- This known example is characterized in that a circuit for correcting the air flow signal according to the reference voltage of the analog-to-digital conversion circuit is interposed between the analog-to-digital conversion circuit and the flow detection circuit. This is a means for correcting the air flow signal in accordance with a change in the reference voltage of the analog-to-digital conversion circuit, and for accurately converting the air-flow signal to analog-to-digital.
- interposing a correction circuit for correcting the air flow signal between the air flow detection circuit and the analog-to-digital conversion circuit in accordance with the reference voltage of the analog-digital conversion circuit includes the correction circuit itself. Therefore, high-precision analog-to-digital conversion methods have not been sufficiently considered.
- the reference power supply for the analog-to-digital converter is a high-precision constant voltage A power supply is used, but this constant power supply voltage fluctuates slightly.
- the drive circuit for detecting the air flow rate and the detection circuit do not depend on the power supply voltage as long as it is equal to or higher than the operating power supply voltage, so that the air flow: 3 ⁇ 4 signal is equal to the reference voltage of the analog-to-digital converter. Is independent. Therefore, the converted value of the air flow signal after the analog-to-digital conversion has an error due to the fluctuation of the reference voltage of the analog-to-digital conversion circuit.
- the conversion formula is as follows.
- the converted value D ai's has an error due to the fluctuation of the reference voltage V cc of the analog-digital conversion circuit.
- the purpose of the present invention is to provide a thermal air flow meter that enables high-accuracy analog-to-digital conversion of an air flow meter signal regardless of fluctuations in the reference voltage of an analog-to-digital conversion circuit. It is to be.
- the present invention has a means for measuring the amount of intake air by heating and controlling a thermal resistor, and an analog-to-digital conversion of an air flow signal of the air flow measuring means.
- Means a reference voltage is input to said analog-to-digital conversion circuit, and said reference voltage is subjected to analog-to-digital conversion by an analog-to-digital conversion circuit, and is converted to a voltage value of said reference voltage.
- the air flow rate f is corrected accordingly.
- the fluctuation of the reference power supply voltage of the A / D converter of the electronic control unit Even in such cases, the air flow signal can be accurately converted to AZD.
- FIG. 1 is a block diagram illustrating an embodiment of the present invention.
- FIG. 2 is a detailed view of a thermal air flow meter illustrating one embodiment of the present invention.
- FIG. 3 is a detailed view of a thermal air flow meter illustrating another embodiment of the present invention.
- FIG. 1 relates to an intake air flow meter according to an embodiment of the present invention, and shows a block diagram showing a thermal air flow meter, an electronic control unit, and an actuator.
- FIG. 2 is a detailed view of an intake air flow meter according to an embodiment of the present invention.
- the thermal air flow meter 1 ⁇ is, for example, a drive circuit 11 (signal output means) for detecting an air flow signal of air flowing through an intake pipe of an engine mounted on a vehicle, and the like.
- AZD converter 13 for converting the converted air flow signal into an analog digital signal (referred to as AZD)
- CPU central processing unit
- a constant-voltage power supply that serves as a reference voltage for the interface 15 that converts the calculated air flow signal into an analog signal
- the thermal air flow meter 10 is connected to the battery power supply 5 i and drives the drive circuit 11. Power supply.
- the air flow signal or air temperature signal of the thermal air flow meter is connected to the AZD converter 33 built in the electronic control unit 30 (for example, the engine control unit ECU).
- the AZD converter 33 receives an analog signal 52 other than the air flow signal manually.
- the electronic control unit 30 is composed of a / 0 converter 33, a CPU 34, an interface 35, and a reference power supply 32, and an air flow signal of the thermal air flow meter 10 or air.
- a reference power supply 32 built in the electronic control unit 30 is a reference power supply for the A / D converter 33.
- the reference power supply 32 built in the electronic control unit ⁇ S 30 is input to the AZD converter 13 built in the thermal air flow meter 10. If the voltage of the reference power supply 32 is referred to as a reference voltage, the reference voltage is input to the ZD converter 13 and the AZD conversion value of the air flow signal detected by the drive circuit 11 is calculated. By performing the calculation, even if the voltage of the reference power supply 32 in the electronic control unit 30, that is, the reference voltage fluctuates, the flow signal of the thermal air flow meter can be accurately converted.
- An embodiment of the present invention will be described in detail with reference to FIG.
- the thermal air flow meter 10 includes a drive circuit for detecting the air flow rate, and includes a thermal resistor 20, a temperature-sensitive resistor 21 for detecting the temperature of intake air, and a resistor 2. It consists of 2, 23, 24, amplifier 25, and transistor 30 and constitutes a drive circuit for detecting the air flow rate.
- the air flow signal is amplified by resistors 27, 28, 29 and an amplifier 26 and further amplified by the drive circuit, and connected to an AZD converter 13. .
- the digital signal of the air flow rate converted by the AZD converter i 3 is digitally processed by the CPU 14, and the processed signal is digitally processed.
- (1) Output as an air flow signal to the air flow output terminal 61 via the analog (D / A) converter 33.
- the temperature of the intake air can be detected by the temperature-sensitive resistor 21 and is used to correct the air flow according to the temperature change of the intake air. Further, the temperature of the intake air is calculated by connecting the voltage across the temperature sensitive resistor 21 to the AZD converter 13 for AZD conversion, and calculating the current flowing through the temperature sensitive resistor 21 by the CPU 14. As a result, digital processing is performed as an intake air temperature signal, and the processed signal is output to an air temperature output terminal 62 via a DZA converter 33 as an intake air temperature signal. The CPU 14 corrects the detected air flow rate signal or air temperature signal based on the data stored in R ⁇ M 3 i and EEPR0M 32 in which data and programs are stored. .
- the DZA converter 43 is necessary when connected to the AZD converter 33 of the electronic control device 30 in FIG. 1, but is required when it is digitally connected to the electronic control device 30. Therefore, the DZA converter 43 is not required. It is determined by the method of transmitting the flow signal with the electronic control unit 30.
- the reference power supply of the AZD converter 13 built in the thermal flow meter 10 is supplied by the constant voltage power supply 12, and the AZD conversion is performed based on the constant voltage Vcc.
- the AZD converter 13 is 8 bits and the voltage of the air flow signal detected and amplified by the thermal resistor 20 is Vafs, the digital conversion value Dafs is It is shown by the formula.
- Dafs Vafs / Vcc ⁇ 2 5 6
- the voltage of the reference power supply 32 built in the electronic control unit 30 is connected to the A / D converter 13 via the reference voltage terminal 63, and if the reference voltage is Vref, The CPU 14 further converts the air flow signal Vafs into a digital signal by the following equation.
- Dout (Vafs / Vcc * 2 5 6) * (AD (Vcc) / AD (Vrcf)) where AD (Vref) is the heat of the reference voltage of the reference power supply 32 of the electronic control unit 32.
- AD (Vcc) is the value obtained by A / D conversion of the voltage of the constant voltage power supply 1 2 by the AZD converter 13 similarly.
- AZD converter] 3 power For example, if it is 8 bits, the value always indicates 2 56 which is 2 8.
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP1996/002628 WO1998011408A1 (fr) | 1996-09-13 | 1996-09-13 | Debimetre d'air thermique |
CNB961804238A CN1168954C (zh) | 1996-09-13 | 1996-09-13 | 热电型气流计 |
EP96930393A EP1014046A4 (en) | 1996-09-13 | 1996-09-13 | THERMAL FLOWMETER |
US09/254,150 US6354275B2 (en) | 1996-09-13 | 1996-09-13 | Thermal air flow meter |
US09/970,897 US6557531B2 (en) | 1996-09-13 | 2001-10-05 | Thermal type air flow meter |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP1996/002628 WO1998011408A1 (fr) | 1996-09-13 | 1996-09-13 | Debimetre d'air thermique |
CNB961804238A CN1168954C (zh) | 1996-09-13 | 1996-09-13 | 热电型气流计 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998011408A1 true WO1998011408A1 (fr) | 1998-03-19 |
Family
ID=25744075
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1996/002628 WO1998011408A1 (fr) | 1996-09-13 | 1996-09-13 | Debimetre d'air thermique |
Country Status (2)
Country | Link |
---|---|
CN (1) | CN1168954C (ja) |
WO (1) | WO1998011408A1 (ja) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101762718B (zh) * | 2010-01-29 | 2012-02-01 | 北京信息科技大学 | 测量风速的方法和装置 |
CN103712659A (zh) * | 2013-12-28 | 2014-04-09 | 苏州谷之道软件科技有限公司 | 一种热式空气流量计 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5077732A (ja) * | 1973-11-14 | 1975-06-25 | ||
JPS6431017A (en) * | 1987-07-28 | 1989-02-01 | Omron Tateisi Electronics Co | Sensor controller |
JPH051617A (ja) * | 1991-06-25 | 1993-01-08 | Aisan Ind Co Ltd | 内燃機関の電子制御装置における吸気量データ入力装置 |
-
1996
- 1996-09-13 WO PCT/JP1996/002628 patent/WO1998011408A1/ja active IP Right Grant
- 1996-09-13 CN CNB961804238A patent/CN1168954C/zh not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5077732A (ja) * | 1973-11-14 | 1975-06-25 | ||
JPS6431017A (en) * | 1987-07-28 | 1989-02-01 | Omron Tateisi Electronics Co | Sensor controller |
JPH051617A (ja) * | 1991-06-25 | 1993-01-08 | Aisan Ind Co Ltd | 内燃機関の電子制御装置における吸気量データ入力装置 |
Non-Patent Citations (1)
Title |
---|
See also references of EP1014046A4 * |
Also Published As
Publication number | Publication date |
---|---|
CN1168954C (zh) | 2004-09-29 |
CN1228159A (zh) | 1999-09-08 |
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