DEVICE FOR DETECTING PHYSICAL QUANTITIES

Abstract

Device for detecting physical quantities (300), comprising: a physical quantity sensor (453) that detects a physical quantity of a measurement target fluid (30) and outputs a detection signal; a compensation amount calculation unit (710) that calculates, by using the detection signal, a derivative compensation amount used in derivative compensation for the detection signal, the derivative compensation being for improving the thermal response characteristic by phase-lead compensation using a high-pass filter; and a gain control unit (730) that adjusts the lead compensation amount based on a deviation that is an amount of change in the lead compensation amount over time.

Description

Technical field

[0001] The present invention relates to a device for detecting physical quantities. Current state of the art

[0002] To control a vehicle, various physical quantities must be measured with high accuracy.

[0003] However, in a vehicle it is difficult to measure physical quantities such as heat and noise with high accuracy, which is problematic.PTL 1 discloses an intake air temperature sensor comprising a secondary passage having an opening for receiving a portion of an intake air flow, a flow rate detecting element disposed in the secondary passage, an electronic circuit electrically connected to the flow rate detecting element, and a circuit mounting plate mounted to the electronic circuit, and further comprising a housing for receiving at least a portion of the circuit mounting plate. The intake air temperature sensor comprises: an intake air temperature detecting element disposed outside the secondary passage; a temperature sensor for detecting a temperature around a mounting portion of the intake air temperature detecting element; and means for correcting an output of the intake air temperature detecting element based on an output of the temperature sensor and an output of the flow rate detecting element. Furthermore, JP H07-83716 A (cf.PTL 2) describes a temperature-sensitive air mass measuring device for internal combustion engines that compensates for delays in response time when the air mass flow changes. The device uses a thermal sensor and performs a two-stage correction calculation – one for high-frequency and one for low-frequency delay components. The correction is performed using discretized formulas that take into account both the current and previous measured values. DE 10 2015 221 958 A1 (cf. PTL 3) describes a method for temperature compensation of a hot-film air mass meter, in which a delay in the temperature measurement is compensated for by a lead compensation. The lead compensation is adaptively adjusted by controlling the gain of the compensation as a function of the rate of change of the temperature signal and the air mass. Finally, US 2008 / 0092645 A1 (cf.PTL 4) a thermal mass air flow sensor with improved response speed. The system uses a lead compensation circuit that corrects the sensor signal delay through phase feedforward control. The compensation is adaptively adjusted by controlling the gain of the lead compensation based on operating parameters such as engine speed and load conditions. List of citationsPatent literature PTL 1: JP 2012-159314 A PTL 2: JP H 078 37 16 A PTL 3: DE 10 2015 221 958 A1 PTL 4: US 2008 / 0092645 A1 Summary of the inventionTechnical problem

[0004] In the configuration disclosed in PTL 1, a plurality of sensors must be included, which poses a problem in terms of an increase in device size and cost. Derivative compensation can be considered as a correction using a single sensor. However, a problem may arise in that overcorrection occurs when a signal changes abruptly due to the influence of an environment or EMC noise. Technical solution

[0005] The problem is solved by the features of claim 1. Particular embodiments are described in the dependent claims. Advantageous effects of the invention

[0006] According to the present invention, overcorrection can be prevented. Short description of the drawings [ Fig. 1] Fig. 1 shows a configuration diagram of an internal combustion engine control system S. [ Fig. 2-1] Fig. 2-1 shows a cross-sectional view of a device 300 for detecting physical quantities. [ Fig. 2-2] Fig. 2-2 shows a cross-sectional view of the physical quantity sensing device 300 with a different configuration. [ Fig. 3] Fig. 3 shows a circuit diagram of the device 300 for detecting physical quantities. [ Fig. 4] Fig. 4 shows a functional block diagram of a microcomputer 415 according to one embodiment. [ Fig. 5] Fig. 5 is a diagram showing an example of a gain characteristic of a compensation amount calculation unit 710. [ Fig. 6-1] Fig. 6-1 shows a diagram illustrating time series changes of a pre-correction temperature TAin and a post-correction temperature TAout during the thermal response of intake air. [ Fig. 6-2] Fig. Figure 6-2 shows a diagram illustrating time series changes of a pre-correction temperature TAin and a post-correction temperature TAout during the occurrence of an external disturbance. [ Fig. 6-3] Fig. 6-3 shows a diagram illustrating time series changes of a pre-correction temperature TAin and a post-correction temperature TAout when the temperature of a measurement target fluid 30 changes stepwise and continuously. [ Fig. 6-4] Fig. 6-4 shows a diagram illustrating a problem of output shift in a pre-correction temperature TAin and a post-correction temperature TAout. [ Fig. 7] Fig. 7 shows a functional configuration diagram of a state determination unit 750. [ Fig. 8-1] Fig. 8-1 is a diagram showing an input and an output of an LPF delay determining unit 751 at the start of the thermal reaction. [ Fig. 8-2] Fig. Figure 8-2 shows a diagram showing a difference between the input and the output in Fig. 8-1. [ Fig. 9] Fig. 9 is a diagram showing an output of a reaction compensation amount determining unit 752. [ Fig. 10] Fig. 10 is a diagram illustrating a filter selection performed by a state selection unit 753. [ Fig. 11] Fig. 11 shows a functional block diagram of a gain control unit 730. [ Fig. 12-1] Fig. 12-1 is a diagram showing an example of an input / output relationship of a first gain coefficient calculation unit 756. [ Fig. 12-2] Fig. 12-2 is a diagram showing an example of an input / output relationship of a second gain coefficient calculation unit 757. [ Fig. 13] Fig. 13 shows a functional block diagram of the microcomputer 415 in Modified Example 1. [ Fig. 14] Fig. 14 shows a functional block diagram of the gain control unit 730 in Modified Example 1. [ Fig. 15] Fig. 15 is a diagram showing an example of an input / output relationship of a third gain coefficient calculation unit 758. [ Fig. 16] Fig. 16 shows a functional block diagram of the microcomputer 415 when correcting an output value of a humidity sensor in Modified Example 2. [ Fig. 17] Fig. 17 shows a functional block diagram of the microcomputer 415 when correcting an output value of a flow rate sensor in Modified Example 2. [ Fig. 18] Fig. 18 is a diagram showing a characteristic of a flow rate characteristic adjusting unit 760. Description of embodiments- Embodiments -

[0007] Embodiments of a device for detecting physical quantities according to the present invention are described below with reference to Fig. 1 to 12-2. The embodiments described below achieve various objects desirable as actual products, and in particular, achieve various objects required for use as a detecting device that detects a physical quantity of intake air in a vehicle, and thus achieve various effects. One of the various objects to be achieved by the embodiments described below is the content described in the technical problem described below, and one of the various effects achieved in the embodiments described below is the effect described in advantageous effects of the invention. Various objects to be achieved by the embodiments described below and various effects achieved by the embodiments described below are described in the description of the embodiments.Therefore, the objects to be achieved by the embodiments and the effects described in the embodiments are also described in contents other than the contents of the technical problem and the advantageous effects of the invention. 1. Combustion engine control system S

[0008] Fig. 1 shows a configuration diagram of an electronic fuel injection internal combustion engine control system S including a physical quantity detection device 300 according to the present invention. In the internal combustion engine control system S, intake air, which is a measurement target fluid 30, moves as follows based on an operation of an internal combustion engine 110 including an engine cylinder 112 and an engine piston 114. That is, the measurement target fluid 30 is first sucked in by an air cleaner 122 and drawn into a combustion chamber of the engine cylinder 112 via a main passage 124, such as an intake body, a throttle body 126, and an intake manifold 128.

[0009] The physical quantity of the measurement target fluid 30 is detected by the physical quantity detecting device 300. A fuel injection valve 152 supplies fuel based on the physical quantity detected by the physical quantity detecting device 300. The fuel supplied from the fuel injection valve 152 is supplied to the combustion chamber in a gas mixture state together with the intake air and burned to generate mechanical energy. The fuel injection valve 152 is arranged, for example, in an intake port of the internal combustion engine, and fuel injected into the intake port forms a gas mixture with the measurement target fluid 30, which is intake air, and is supplied to the combustion chamber through an intake valve 116.

[0010] Fuel and air supplied to the combustion chamber are in a fuel-air mixture state and are explosively combusted by spark ignition of a spark plug 154, thereby generating mechanical energy. The gas after combustion is supplied to an exhaust pipe from an exhaust valve 118 and is discharged as exhaust gas 24 from the exhaust pipe to the outside of the vehicle. The flow rate of the measurement target fluid 30, which is the intake air supplied to the combustion chamber, is controlled by a throttle valve 132, the opening degree of which changes based on an operation of an accelerator pedal. A fuel supply amount is controlled based on the flow rate of the intake air supplied to the combustion chamber. A driver can control the opening degree of the throttle valve 132 to control the flow rate of the intake air supplied to the combustion chamber, thereby controlling the mechanical energy generated by the internal combustion engine. 1.1 Overview of the control of the internal combustion engine control system S

[0011] The physical quantity detecting device 300 detects a physical quantity, such as a flow rate, temperature, humidity, or pressure, of the measurement target fluid 30, which is the intake air supplied from the air cleaner 122 and flowing through the main passage 124. An electrical signal representing the physical quantity of the intake air is input from the physical quantity detecting device 300 to a control device 200. An output of the throttle angle sensor 144, which measures the opening degree of the throttle valve 132, is input to the control device 200. The positions or states of the engine piston 114, the intake valve 116, and the exhaust valve 118 of the internal combustion engine are input to the control device 200. Furthermore, the output of the rotation angle sensor 146 is input to the control device 200 to measure a rotational speed of the internal combustion engine.An output of an oxygen sensor 148 is input to the controller 200 to measure a state of a mixture ratio of a fuel amount and an air amount based on a state of the exhaust gases 24.

[0012] The control device 200 calculates a fuel injection amount and ignition timing based on the physical quantity of the intake air, which is the task of the physical quantity detecting device 300, and the engine speed measured based on the output of the rotation angle sensor 146. Based on the calculation results, the amount of fuel supplied from the fuel injection valve 152 and the ignition timing at which ignition occurs by the spark plug 154 are controlled. In the current embodiment, the fuel supply amount and ignition timing are also precisely controlled based on a change in the temperature or throttle angle detected by the physical quantity detecting device 300, a change in the engine speed, and a change in the air-fuel ratio measured by the oxygen sensor 148.In addition, the control device 200 controls the rotational speed of the internal combustion engine in an idle operating state by controlling an amount of air bypassing the throttle valve 132 with an idle air control valve 156 in the idle operating state of the internal combustion engine. 1.2 Significance of Improving the Detection Accuracy of the Physical Quantity Detection Device 300 and the Installation Environment of the Physical Quantity Detection Device 300

[0013] Both the fuel supply amount and the ignition timing, which are main control amounts of the internal combustion engine, are calculated using the output of the physical quantity detecting device 300 as a main parameter. Therefore, it is essential to improve the detection accuracy of the physical quantity detecting device 300, prevent changes over time, and improve reliability in terms of improving vehicle control accuracy or ensuring reliability.

[0014] In particular, in recent years, there has been a strong demand for vehicle fuel efficiency and exhaust gas purification. To meet these demands, it is extremely important to improve the accuracy of detecting the physical quantity of the intake air, which physical quantity is detected by the physical quantity detecting device 300. It is also essential that the physical quantity detecting device 300 ensure high reliability.

[0015] The vehicle in which the physical quantity detecting device 300 is installed is used in an environment where a change in temperature or humidity is large. It is desirable for the physical quantity detecting device 300 to cope with a change in temperature and humidity in the use environment and with dust or contaminants. Further, the physical quantity detecting device 300 is attached to an intake pipe affected by heat generated by the internal combustion engine. Therefore, the heat generated by the internal combustion engine is transferred to the physical quantity detecting device 300 via the intake pipe, which constitutes the main passage 124.Since the physical quantity detecting device 300 detects the flow rate of the measurement target fluid 30 by performing heat transfer with the measurement target fluid 30, influence of heat from the outside must be prevented as much as possible. 2. Configuration of the physical quantity detecting device 300 2.1 External structure of the physical quantity detecting device 300

[0016] Fig. 2-1 shows a cross-sectional view of the physical quantity detecting device 300. The physical quantity detecting device 300 includes a housing 302. The housing 302 is formed by molding a synthetic resin material. The housing 302 includes a flange 311 for fixing the physical quantity detecting device 300 to the intake body constituting the main passage 124, an external connection portion 321 including a connector protruding from the flange 311 and configured for electrical connection with an external device, and a sensing portion 331 extending so as to protrude from the flange 311 toward the center of the main passage 124.

[0017] A circuit board 400 is arranged in the measuring section 331. At least a detection section for detecting the physical quantity of the measurement target fluid 30 flowing through the main channel 124 and a circuit section for processing the signal detected by the detection section are arranged in the circuit board 400. The detection section is arranged at a position exposed to the measurement target fluid 30, and the circuit section is arranged in a closed circuit chamber. Various materials can be used as the material of the circuit board 400. For example, a material formed of a glass epoxy resin is preferable because it is inexpensive and easy to process.

[0018] A first sub-channel 305 is formed in the measuring section 331. A first sub-channel inlet 305a for receiving a portion of the measurement target fluid 30, such as intake air, into the first sub-channel 305 and a first sub-channel outlet 305b for returning the measurement target fluid 30 from the first sub-channel 305 to the main channel 124 are respectively disposed at end portions of the measuring section 331. A portion of the circuit board 400 protrudes in the center of the first sub-channel 305, and a flow rate detection portion 602 as a detection portion is disposed in the protruding portion to detect the flow rate of the measurement target fluid 30.

[0019] The external connection portion 321 is disposed on an upper surface of the flange 311 and includes the connector. The connector is provided with an insertion hole for inserting a connection cable for connecting to the control device 200. An external terminal is disposed in the insertion hole. The external terminal serves as a terminal for outputting physical quantity information, which is a measurement result of the physical quantity detecting device 300, and a power supply terminal for supplying direct current for operating the physical quantity detecting device 300. 2.2 Effects based on the external structure of the device 300 for detecting physical quantities

[0020] In the physical quantity detecting device 300, a protruding portion 403 is disposed in a central portion of the measuring portion 331 extending from the flange 311 to the center of the main channel 124, and the first sub-channel inlet 305a is disposed at the end portion of the measuring portion 331. Thus, gas near a central portion of the main channel that is remote from an inner wall surface of the main channel 124 can be introduced into each of the protruding portion 403 and the first sub-channel 305, not near the inner wall surface. Thus, the physical quantity detecting device 300 can measure the physical quantity of the gas in a portion of the main channel 124 remote from the inner wall surface and can reduce an error in measuring physical quantities caused by heat and a decrease in flow velocity near the inner wall surface. 2.3 Appearance of the 400 circuit board

[0021] The circuit section is configured by mounting electronic components such as a microcomputer 415, a power supply regulator 416, an on-board temperature sensor 423, and a chip component 417 such as a resistor or a capacitor on a circuit wiring (not shown).

[0022] The protruding portion 403 is arranged in the first sub-channel 305, and the measurement flow channel surface 430, which is a surface of the protruding portion 403, extends along a flow direction of the measurement target fluid 30. The flow rate detecting portion 602 is arranged on the measurement flow channel surface 430 of the protruding portion 403.

[0023] The flow rate detecting section 602 performs heat transfer with the measurement target fluid 30, measures a state of the measurement target fluid 30, for example, the flow velocity of the measurement target fluid 30, and outputs an electrical signal indicative of the flow rate in the main channel 124. 2.4 Structure of the temperature detection section 451

[0024] A temperature detection section 451 is arranged at a portion corresponding to an upstream side edge and a corner of a base section 402, the corner being adjacent to the protruding section 403. The temperature detection section 451 constitutes one of the detection sections for detecting the physical quantity of the measurement target fluid 30 flowing through the main channel 124 and is arranged on the circuit board 400. The circuit board 400 has a protruding section 450 protruding toward an upstream side of the measurement target fluid 30, and the temperature detection section 451 includes a chip temperature sensor 453 arranged in a portion corresponding to the protruding section 450 and a back side of the circuit board 400. The temperature sensor 453 and a wiring section thereof are covered with a synthetic resin material to prevent electrolytic corrosion due to the adhesion of salt water.

[0025] Fig. 2-2 is an appearance view showing another configuration of the physical quantity detecting device 300. In the Fig. 2-1, the device 300 for detecting physical quantities includes the temperature sensor 453, and the temperature sensor 453 is implemented as a chip. However, the configuration of the device 300 for detecting physical quantities is not limited to the configuration shown in Fig. 2-1 shown configuration and it can be, for example, an axial design as in Fig. 2-2 or any other configuration can be used. 3. Circuit configuration of the device 300 for detecting physical quantities 3.1 Overall circuit configuration of the device 300 for detecting physical quantities

[0026] Fig. Figure 3 shows a circuit diagram of the physical quantity detecting device 300. The physical quantity detecting device 300 includes a flow rate detecting circuit 601, a temperature / humidity detecting circuit 701, the microcomputer 415, and the power supply controller 416.

[0027] The flow rate detection circuit 601 includes a flow rate detection section 602 including a heating element 608 and a processing unit 604. The processing unit 604 controls a heat generation amount of the heating element 608 of the flow rate detection section 602 and outputs a signal indicative of the flow rate to the microcomputer 415 via a terminal 662 based on an output of the flow rate detection section 602. To perform this processing, the processing unit 604 includes a CPU 612 that is a central processing unit, an input circuit 614, an output circuit 616, a memory 618 that stores data indicating a correction value or a relationship between a measured value and a flow rate, and a power supply circuit 622 that supplies a specific voltage to each of the required circuits.DC power is supplied to the power supply circuit 622 from an external power supply, such as a battery in the vehicle, via a terminal 664 and a ground terminal (not shown).

[0028] The heating element 608 for heating the measurement target fluid 30 is arranged in the flow rate detection section 602. A voltage V1 is supplied from the power supply circuit 622 to a collector of a transistor 606, which constitutes a power supply circuit of the heating element 608. A control signal is applied from the CPU 612 to a base of the transistor 606 via the output circuit 616. Based on this control signal, a current is supplied from the transistor 606 to the heating element 608 via a terminal 624. The amount of current supplied to the heating element 608 is controlled by the control signal applied from the CPU 612 to the transistor 606 via the output circuit 616. The transistor 606 constitutes the power supply circuit of the heating element 608.The processing unit 604 controls the heat generation amount of the heating element 608 so that the temperature of the measurement target fluid 30 becomes higher than an initial temperature by a predetermined temperature, for example, 100°C, due to heating by the heating element 608.

[0029] The flow rate detection section 602 includes a heat generation control bridge 640 for controlling the heat generation amount of the heating element 608 and a flow rate detection bridge 650 for measuring the flow rate. A predetermined voltage V3 is supplied from the power supply circuit 622 to one end of the heat generation control bridge 640 via a terminal 626, and the other end of the heat generation control bridge 640 is connected to a ground terminal 630. Further, a predetermined voltage V2 is supplied from the power supply circuit 622 to one end of the flow rate detection bridge 650 via a terminal 625, and the other end of the flow rate detection bridge 650 is connected to the ground terminal 630.

[0030] The heat generation control bridge 640 includes a resistor 642, which is a temperature measuring resistor whose resistance value changes based on the temperature of the heated measurement target fluid 30. The resistor 642, a resistor 644, a resistor 646, and a resistor 648 form a bridge circuit. A potential difference between a cross point A between the resistors 642 and 646 and an intersection point B between the resistors 644 and 648 is input to the input circuit 614 via terminals 627 and 628. The CPU 612 controls the heat generation amount of the heating element 608 by controlling a current supplied by the transistor 606 so that the potential difference between the cross point A and the cross point B becomes a predetermined value, for example, zero volts.

[0031] The Fig. The flow rate detection circuit 601 shown in FIG. 3 heats the measurement target fluid 30 with the heating element 608 so that the temperature of the measurement target fluid 30 becomes higher than the initial temperature by a predetermined temperature, for example, 100°C. To perform heating control with high accuracy, a resistance value of each resistor included in the heat generation control bridge 640 is set as follows. That is, the resistance value of each resistor is set so that the potential difference between the cross point A and the cross point B becomes zero volts each time the temperature of the measurement target fluid 30 heated by the heating element 608 becomes higher than the initial temperature by a predetermined temperature, for example, 100°C.Therefore, the CPU 612 of the flow rate detecting circuit 601 controls a current to be supplied to the heating element 608 so that the potential difference between the crossing point A and the crossing point B becomes zero volts.

[0032] The flow rate detection bridge 650 includes four temperature measuring resistors including a resistor 652, a resistor 654, a resistor 656, and a resistor 658. These four temperature measuring resistors are arranged along the flow of the measurement target fluid 30. The resistors 652 and 654 are arranged upstream of a flow channel of the measurement target fluid 30 with respect to the heating element 608. The resistors 656 and 658 are arranged downstream of a flow channel of the measurement target fluid 30 with respect to the heating element 608. Furthermore, to improve measurement accuracy, the resistors 652 and 654 are arranged so that distances to the heating element 608 are substantially the same. Likewise, to improve measurement accuracy, the resistors 656 and 658 are arranged so that distances to the heating element 608 are substantially the same.

[0033] A potential difference between a cross point C between resistors 652 and 656 and an intersection point D between resistors 654 and 658 is input to the input circuit 614 via terminals 631 and 632. To improve measurement accuracy, each resistor of the flow rate detection bridge 650 is set so that the potential difference between the cross point C and the cross point D becomes zero in a state where, for example, the flow of the measurement target fluid 30 is zero. Therefore, in a state where the potential difference between the cross point C and the cross point D is, for example, zero volts, the CPU 612 outputs, via terminal 662, an electrical signal indicating that the flow rate in the main channel 124 is zero based on a measurement result that the flow rate of the measurement target fluid 30 is zero.

[0034] When the measurement target fluid 30 is in an arrow direction in Fig. 3 flows, that is, when the target fluid 30 flows from top to bottom in Fig. 3, the operation of the flow rate detection bridge 650 is as follows. The resistors 652 and 654 arranged on the upstream side are cooled by the measurement target fluid 30. The resistors 656 and 658 arranged on the downstream side of the measurement target fluid 30 are heated by the measurement target fluid 30 heated by the heating element 608, and thus the temperatures of the resistors 656 and 658 rise.

[0035] Thus, a potential difference is generated between the crossing point C and the crossing point D of the flow rate detection bridge 650, and the potential difference is input to the input circuit 614 via the terminals 631 and 632. The CPU 612 retrieves data indicating the relationship between the aforementioned potential difference and the flow rate in the main channel 124 and stored in the memory 618 based on the potential difference between the crossing point C and the crossing point D of the flow rate detection bridge 650, and calculates the flow rate in the main channel 124. An electrical signal representing the flow rate in the main channel 124 calculated as described above is output via the terminal 662.

[0036] The memory 618 stores data indicating the relationship between the potential difference between the crossing point C and the crossing point D and the flow rate in the main channel 124. The memory 618 further stores correction data for reducing a measurement error such as a variation, the correction data being determined based on an actual measurement value of the gas after the circuit board 400 is manufactured.

[0037] The temperature / humidity detection circuit 701 includes an input circuit, such as an amplifier or A / D converter, to which a detection signal from the onboard temperature sensor 423 and a humidity sensor 422 is input; an output circuit, a memory that stores data indicating a correction value or a relationship between a temperature and an absolute humidity; and the power supply circuit 622 that supplies a specific voltage to each of the required circuits. The signal output from each of the flow rate detection circuit 601 and the temperature / humidity detection circuit 701 is input to the microcomputer 415. Hereinafter, a flow rate represented by a flow rate signal input from the flow rate detection circuit 601 to the microcomputer 415 is referred to as a pre-correction flow rate FAin.The microcomputer 415 receives a specific voltage, which is an output value of the temperature sensor 453, and converts the voltage into a temperature according to a predetermined characteristic. Hereinafter, the temperature obtained by the conversion is referred to as the pre-correction temperature TAin.

[0038] The microcomputer 415 includes a CPU, which is a central processing unit, a read-only memory (ROM), which is a write-protected non-volatile memory area, and a random access memory (RAM), which is a read / write memory area. The CPU of the microcomputer 415 performs a function described below by loading a program stored in the ROM into the RAM and executing the program. The pre-correction flow rate FAin and the pre-correction temperature TAin are input to the microcomputer 415. The microcomputer 415 performs processing described below and outputs a post-correction flow rate FAout and a post-correction temperature TAout to the control device 200.The physical quantity acquisition device 300 and the control device 200 are connected by a connecting cable, and communication using a digital signal is performed according to a communication standard such as SENT, LIN (registered trademark), or CAN (registered trademark). The post-correction flow rate FAout and the post-correction temperature TAout output from the microcomputer 415 are used by the control device 200 for various engine operation control operations. 4. Correction method of the device 300 for detecting physical quantities 4.1 Correction method of the device 300 for detecting physical quantities

[0039] Fig. 4 shows a functional block diagram illustrating each function of the microcomputer 415 as a block. The pre-correction flow rate FAin and the pre-correction temperature TAin are input to the microcomputer 415, and the microcomputer 415 outputs the post-correction flow rate FAout and the post-correction temperature TAout. The processing performed by the microcomputer 415 also includes conversion processing that matches a predetermined characteristic; however, here, characteristic conversion is also referred to as correction for the sake of simplicity. The microcomputer 415 performs processing every predetermined processing period.

[0040] The microcomputer 415 includes, as functions thereof, a flow rate characteristic adjustment unit 760, a compensation amount calculation unit 710, a deviation determination unit 720, a timer unit 721, a moving average filter 722, a gain control unit 730, an addition processing unit 731, a noise attenuation processing unit 740 which is a low-pass filter (hereinafter referred to as LPF), and a state determination unit 750. The functions of the microcomputer 415 can be performed by using the LSI 414 or can be performed by using a hardware circuit. (Overview of each function block)

[0041] The flow rate characteristic adjustment unit 760 converts the pre-correction flow rate FAin, which is the output value of the flow rate detection circuit 601, according to a predetermined characteristic and outputs it as AveQ. However, the characteristic is affected by the post-correction flow rate FAout as described below. The flow rate characteristic adjustment unit 760 converts, for example, a non-linear output value of the flow rate detection circuit 601 into a linear value suitable for calculation processing. The compensation amount calculation unit 710 calculates a compensation amount for increasing the thermal response speed of the post-correction temperature TAout, which is the output of the microcomputer 415, by using the output value AveQ of the flow rate characteristic adjustment unit 760 and the pre-correction temperature TAin, and outputs the compensation amount as TAhp.The compensation amount calculation unit 710 in turn sets the output TAhp to zero while a stop command is issued from the timer unit 721.

[0042] The characteristic conversion unit 765 converts the characteristic according to the characteristic of the control device 200 using the output of the physical quantity detection device 300, and outputs the converted characteristic as the post-correction flow rate FAout. That is, the characteristic conversion unit 765 converts the characteristic of the output AveQ of the flow rate characteristic adjustment unit 760 to determine the post-correction flow rate FAout.

[0043] TA_mva, which is an output of the moving average filter 722, is input to the deviation determination unit 720. A deviation is determined based on a time-series change of the input value, and a determination result is output as Dd to the timer unit 721. The timer unit 721 issues the stop command to the compensation amount calculation unit 710 for a predetermined time according to the determination result Dd of the deviation determination unit 720. The moving average filter 722 applies the moving average filter to the output TAhp of the compensation amount calculation unit 710 and outputs, as TA_mva, the output of the noise-reduced compensation amount calculation unit 710 to the gain control unit 730, the deviation determination unit 720, and the state determination unit 750.

[0044] The gain control unit 730 determines a gain of the compensation amount calculated by the compensation amount calculation unit 710 based on a response state of the physical quantity detection device 300. Subsequently, the gain control unit 730 calculates TAadd by multiplying the determined gain and the output TA_mva of the moving average filter 722 and outputs TAadd to the addition processing unit 731. The addition processing unit 731 calculates TA_resp by adding the output TAadd of the gain control unit 730 and the pre-correction temperature TAin and outputs TA_resp to the noise attenuation processing unit 740 and the state determination unit 750. The noise reduction processing unit 740 applies a low-pass filter to reduce noise included in the output TA_resp of the addition processing unit 731 and outputs a result thereof as the post-correction temperature TAout.

[0045] The state determination unit 750 determines the response state of the physical quantity detecting device 300 based on the output value TA_mva of the moving average filter 722, the output value TA_resp of the addition processing unit 731, and the post-correction temperature TAout, which is the output value of the noise reduction processing unit 740. The response state of the physical quantity detecting device 300 is a state of response of the temperature sensor 453 of the physical quantity detecting device 300 to external heat. That is, determining the response state of the physical quantity detecting device 300 consists of determining whether the temperature sensor 453 is in a state of changing output, that is, a response state, or in a steady state where the output is constant.The state determination unit 750 selects a filter based on a determination result as described below and outputs a signal indicating the selected filter as TA_SelSw to the gain control unit 730. (Influence of heat)

[0046] Since the temperature sensor 453 is installed in the physical quantity detecting device 300, a thermal response characteristic of the post-correction temperature TA obtained by converting the output of the temperature sensor 453 is influenced by a thermal capacity of the physical quantity detecting device 300. A thermal time constant of the casing 302 of the physical quantity detecting device 300 is several tens of times larger than a thermal time constant of the temperature detecting section 451. The heat of the casing 302 makes the temperature of the entire printed circuit board 400 uniform through conductor wiring with very high thermal conductivity.

[0047] Therefore, in the temperature detection section 451, in addition to the heat transfer from the intake air, which is the measurement target fluid 30, heat conduction occurs through the housing 302 and the circuit board 400, and thus the thermal responsiveness of the pre-correction temperature TA deteriorates. Specifically, the influence of heat conduction becomes relatively large in a lower flow rate range where the influence of heat transfer from the intake air decreases, and a response delay of the pre-correction temperature TA increases. Thus, in the compensation amount calculation unit 710, the thermal response characteristic of the post-correction temperature TAout is improved by applying phase-ladder compensation using a high-pass filter (hereinafter referred to as "HPF"). (Flow characteristic adjustment unit 760)

[0048] Fig. 18 shows a diagram illustrating a characteristic of the flow rate characteristic adjustment unit 760. The flow rate characteristic adjustment unit 760 outputs AveQ based on the pre-correction flow rate FAin and the post-correction temperature TAout. That is, a relationship between the pre-correction flow rate FAin, the post-correction temperature TAout, and AveQ can be expressed by a three-dimensional graph in which the pre-correction flow rate is on an X-axis, the post-correction temperature TAout is on a Y-axis, and AveQ is on a Z-axis. Fig. 18, however, the relationship to the simplified drawing representation is expressed two-dimensionally.

[0049] Since the flow rate detection circuit 601 detects the flow rate using the heating element, the pre-correction flow rate FAin is affected by the temperature. Therefore, a relationship between the flow rate and the temperature is stored in advance, and AveQ is output according to the pre-correction flow rate FAin and the post-correction temperature TAout. As described above, a temperature characteristic of the pre-correction flow rate FAin varies depending on the flow rate. Although in Fig. 18 a graph is shown, a mathematical expression or a variety of tables can be used instead of the graph. (Compensation amount calculation unit 710)

[0050] Fig. 5 is a diagram showing a gain characteristic of the HPF in the compensation amount calculation unit 710. As in Fig. As shown in Figure 5, the gain of the HPF tends to decrease as the output value AveQ of the flow rate characteristic adjustment unit 760 increases. By determining the gain of the HPF in this way, response compensation can be performed according to a time constant. Since the pre-correction flow rate FAin is corrected to AveQ linearized by the flow rate characteristic adjustment unit 760, setting the gain according to the flow rate can be simplified.

[0051] Furthermore, considering an influence of the self-heat generation of the circuit board 400, the heat generation from the internal combustion engine, or the like, a time constant in the output of the temperature sensor 453 may be different between the thermal response on a heating side and the thermal response on a cooling side, even if the measurement target fluid 30 changes in a similar manner. That is, the time constant of the pre-correction temperature TAin may differ between a case where the pre-correction temperature TAin increases and a case where the pre-correction temperature TAin decreases. To cope with such a case, the gain of the HPF of the compensation amount calculation unit 710 may be switched between heating and cooling.In particular, in the case of heating, i.e., when the pre-correction temperature TAin increases in a time-series manner, the gain increases, and in the case of cooling, i.e., when the pre-correction temperature TAin decreases in a time-series manner, the gain decreases. However, the magnitude of the gain can also be set in the opposite direction.

[0052] Fig. 6-1 and 6-2 show diagrams illustrating a relationship between the pre-correction temperature TAin and the post-correction temperature TAout. Fig. 6-1 is a diagram showing an example of a time series change of the output of the temperature sensor 453 during the thermal response of intake air and Fig. Figure 6-2 is a diagram showing an example of a time series change of the temperature sensor when the output of the temperature sensor 453 changes abruptly due to an external disturbance. The difference between Fig. 6-1 and Fig. 6-2 consists in a rate of change of the pre-correction temperature TAin. In Fig. 6-1, the change of the pre-correction temperature TAin is relatively gradual and its time constant is several seconds to several tens of seconds. In Fig. 6-2, the change of the pre-correction temperature TAin is fast and a time constant thereof is several seconds.

[0053] In general, the temperature of a measurement target gas is unlikely to change rapidly, and a time constant τ of the temperature change is usually assumed to be several seconds to several tens of seconds. However, the pre-correction temperature TAin may change rapidly in a short time, such as in a water-cooled environment or when an external disturbance such as EMC noise occurs. The compensation amount calculation unit 710 designs the high-pass filter under the assumption that the temperature change of the measurement target occurs gradually, that is, the time constant τ is several seconds to several tens of seconds, and thus a favorable response as in Fig. 6-1 for an expected input. However, if the pre-correction temperature TAin changes abruptly due to an external disturbance, if the state determination unit 750 or the gain control unit 730 is not present, an overshoot caused by overcorrection occurs in the post-correction temperature TAout as shown in Fig. 6-2. Therefore, the deviation determination unit 720 described below is provided. (Deviation determination unit 720)

[0054] The deviation determination unit 720 calculates a deviation that is a difference between an output value of the compensation amount calculation unit 710 at a time t and an output value of the compensation amount calculation unit 710 at a time t-1, thereby classifying a temperature change due to the intake air and a rapid temperature change due to an external disturbance.

[0055] Here, a maximum deviation that can result from the temperature change due to the intake air is used as a threshold value. Specifically, a threshold value TA_diff is a difference between a maximum temperature and a minimum temperature at which the physical quantity detection device 300 can operate according to a specification. When a relationship shown in Expression 1 is satisfied, that is, when it is determined that an absolute value of a deviation DT exceeds the threshold value TA_diff, the deviation determination Dd is true, and it is determined that an output change due to an external disturbance has occurred in the temperature sensor 453. DT=|TA_mva(t)−TA_mva(t−1)|DT≥TA_diff where TA_mva (t) is an output value of the moving average filter 722 at time t.

[0056] When the output Dd of the deviation determination unit 720 is true, the timer unit 721 issues the stop command to the compensation amount calculation unit 710 for a predetermined time. Thus, the output of the compensation amount calculation unit 710 becomes zero, and the occurrence of overcorrection is prevented.

[0057] Furthermore, by providing the moving average filter 722 in the following stage of the compensation amount calculation unit 710, noise of the deviation value is reduced, so that occurrence of erroneous determination due to noise can be prevented and the stability of the deviation determination can be improved. (Needs further improvement)

[0058] Fig. 6-3 is a diagram illustrating a problem of the compensation amount calculation unit 710 when the temperature of the measurement target fluid 30 changes stepwise and continuously. When the temperature of the measurement target fluid 30 changes stepwise and continuously, for example, when the time constant is on the order of several hundred seconds and the gain control unit 730 is not provided, a derivative compensation is applied to an input value for the post-correction temperature TAout, resulting in overcorrection.

[0059] Fig. Figure 6-4 is a diagram illustrating a problem of output shift in the compensation amount calculation unit 710. In addition to the compensation amount calculation unit 710, when a filter such as a high-pass filter is used, output shift may occur due to the influence of a calculation error in a steady state where there is little change in the intake air temperature, not during thermal response. When output shift occurs, the output shifts by a predetermined amount as shown in Fig. 6-4, which means the output is distorted.

[0060] To solve the problem of the compensation amount calculation unit 710 as shown in Fig. 6-3 and Fig. 6-4, a situation in which the output of the compensation amount calculation unit 710 is used without change is limited as follows. That is, the situation is limited to the rapid temperature change (time constant τ: order of several to several tens of seconds) due to the intake air, in which the temperature changes gradually as in Fig. 6-1 changes. In other temperature output change states, the gain of the derivative action compensation by the HPF is reduced, or the derivative action compensation operation by the HPF is stopped. The state determination unit 750 is provided to perform this. (Condition determination unit 750)

[0061] The state determination unit 750 makes a determination based on the output values of the moving average filter 722, the addition processing unit 731, and the noise attenuation processing unit 740, and classifies the temperature change state due to the intake air to which the above-described HPF is to be applied and other temperature change states.

[0062] Fig. 7 shows a functional configuration diagram of a state determination unit 750. The state determination unit 750 includes a LPF delay determination unit 751, a reaction compensation amount determination unit 752, and a state selection unit 753. The LPF delay determination unit 751 determines whether TAresp and the post-correction temperature TAout satisfy the condition of the following Expression 2 or not. "True" is output when it is determined that the condition of Expression 2 is satisfied, and "False" is output when it is determined that the condition is not satisfied. Since the output values before and after passing the LPF at time t are not calculated at the time of performing the LPF delay determination at time t, the output values before and after passing the LPF at time t-1, which is the immediately preceding processing period, are buffered and used for determination.Furthermore, in Expression 2, TA_delay is a predetermined threshold. |TA_resp(t−1)−TAout(t−1)|≥TA_delay

[0063] Fig. 8-1 is a diagram showing an input and an output of the LPF delay determining unit 751 at the start of the thermal reaction. Fig. Figure 8-2 shows a diagram showing a difference between the input and the output in Fig. 8-1. In Fig. In Figures 8-1 and 8-2, the scale of the vertical axis is different; however, the scale of the horizontal axis is the same. When the thermal response starts, TA_resp changes before the low-pass filter is applied earlier than the post-correction temperature TAout after the low-pass filter is applied, as shown in Fig. 8-1. Then, as shown in Fig. As shown in Figure 8-2, the difference between TA_resp and the post-correction temperature TAout increases sharply and then decreases gradually. The description is again based on Fig. 7 continued.

[0064] The reaction compensation amount determination unit 752 detects the thermal reaction using a characteristic that the derivative compensation is applied by the HPF due to the temperature change and a reaction correction amount increases during the thermal reaction.

[0065] When an output of the reaction compensation amount determination unit 752 itself is true, the reaction compensation amount determination unit 752 determines whether the condition of Expression 3 is satisfied or not, and when the output of the reaction compensation amount determination unit 752 itself is false, the reaction compensation amount determination unit 752 determines whether the condition of Expression 4 is satisfied or not. |TA_mva|≥TA_mva_Hys−TA_mva_Offset |TA_mva|≥TA_mva_Hys

[0066] In Expressions 3 and 4, TA_mva_Hys is a reaction compensation amount threshold and TA_mva_Offset is a reaction compensation amount threshold offset.

[0067] Both are predetermined constants. As a method for determining these constants, for example, the response compensation amount threshold may be a maximum deviation that can result from the ramp response, and the response compensation amount threshold offset may be determined based on an assumed noise level. The response compensation amount determination unit 752 refers to Expression 3 or Expression 4, outputs "True" when it is determined that an inequality relationship described in each expression is satisfied, and outputs "False" when it is determined that the inequality relationship described in each expression is not satisfied.

[0068] Expressions 3 and 4 are described below. In a certain HPF constant setting in the compensation amount calculation unit 710, the response compensation amount may change due to a slight change in the output of the temperature sensor 453 caused by an influence of a calculation error, and the response compensation amount may exceed the threshold in a short time. To avoid such a problem, the threshold of the response compensation amount has a hysteresis characteristic. Specifically, Expression 3 including the offset or Expression 4 not including the offset is used according to the output of the LPF delay determination unit 751. The threshold values shown in Expressions 3 and 4 may be referred to as thresholds with hysteresis characteristics or hysteresis thresholds.

[0069] Fig. 9 is a diagram showing an output of the reaction compensation amount determining unit 752. In Fig. 9, a horizontal axis represents the time course and a vertical axis represents a value of TA_mva, which is the input value of the reaction compensation amount determination unit 752. At a value shown on the left side of Fig. At time t0 shown in FIG. 9, the output of the reaction compensation amount determination unit 752 was "False." Subsequently, TA_mva increased, and at time t1, TA_mva became TA_mva_Hys or more. Since the output of the reaction compensation amount determination unit 752 was "False" immediately before time t1, the reaction compensation amount determination unit 752 makes a determination using Expression 4 that does not include TA_mva_Offset. At time t1, the reaction compensation amount determination unit 752 determines that the inequality relationship in Expression 4 is satisfied and thus outputs "True," and then the reaction compensation amount determination unit 752 makes a determination using Expression 3 including TA_mva_Offset. Thus, at time t2, TA_mva has the same value as that at time t1; However, the output of “True” is retained and the output changes to “False” at a time t3.By properly using Expression 3 and Expression 4 in this way, the hysteresis characteristic is provided.

[0070] The previously described LPF delay determination unit 751 can determine a reaction start time; however, it is difficult to continue detection until the reaction ends. In addition, the reaction compensation amount determination unit 752 performs detection even at the time of a gradual temperature change in a ramp response manner due to the intake air. Therefore, the state selection unit 753 is further provided, and determination results of the LPF delay determination unit 751 and the reaction compensation amount determination unit 752 are combined to classify the previously described state to which the HPF is to be applied and other states.

[0071] Fig. 10 is a diagram illustrating the state selection performed by the state selection unit 753. The state selection unit 753 selects a state according to the outputs of the LPF delay determination unit 751 and the reaction compensation amount determination unit 752. Since the LPF delay determination unit 751 and the reaction compensation amount determination unit 752 each output "True" or "False," there are four combinations in total. Here, the four combinations are referred to as Cases 1 to 4.

[0072] The state selection unit 753 selects a reaction state (TA_SelSw = 1) in Case 1, in which the outputs of the TPF delay determination unit 751 and the reaction compensation amount determination unit 752 are both "True." The state selection unit 753 maintains a selected state in the previous processing period in Cases 2 and 3, in which the outputs of the TPF delay determination unit 751 and the reaction compensation amount determination unit 752 do not match, that is, one of the outputs is "True" and the other is "False." The state selection unit 753 selects a steady state (TA_SelSw = 0) in Case 4, in which the outputs of the TPF delay determination unit 751 and the reaction compensation amount determination unit 752 are both "False."

[0073] The HPF can be used for the reaction state, and a state in which the gain of the derivative action compensation by the HPF is reduced, or a state in which the derivative action compensation operation by the HPF is stopped and no filtering processing is performed, can be used for the steady state. Since the state selection unit 753 switches the filter only when the determination results of the LPF delay determination unit 751 and the reaction compensation amount determination unit 752 agree, frequent state switching can be prevented when the determination results of the LPF delay determination unit 751 and the reaction compensation amount determination unit 752 change near the threshold value, thereby improving stability in the state determination. (Gain control unit 730)

[0074] Fig. 11 is a functional block diagram illustrating a plurality of functions of the gain control unit 730 as blocks. The gain control unit 730 includes a unit 754 for calculating the elapsed time after a state change, a unit 755 for calculating a temperature difference after a state change, a first gain coefficient calculation unit 756, and a second gain coefficient calculation unit 757. The gain control unit 730 multiplies TA_mva, which is the output value of the moving average filter 722, by a first gain G1 and a second gain G2, and outputs a product thereof as TAadd. Details of the gain control unit 730 are described below.

[0075] TA_SelSw, which is the output of the state determination unit 750, is input to the post-state change elapsed time calculation unit 754, and the post-state change elapsed time calculation unit 754 outputs an elapsed time to the first gain coefficient calculation unit 756. Specifically, the post-state change elapsed time calculation unit 754 stores a counter C as an internal variable and outputs a value of the counter C as information indicating the elapsed time. The post-state change elapsed time calculation unit 754 increments the time each time the processing period elapses and resets the counter C to zero when TA_SelSw changes.That is, if the value TA_SelSw at time t is represented as TA_SelSw(t), the unit 754 for calculating the time elapsed after a state change resets the counter C if expression 5 is satisfied. TA_SelSw(t−1)!=TA_SelSw(t)

[0076] The first gain coefficient calculation unit 756 determines a gain coefficient based on the value of the counter C output from the state change elapsed time calculation unit 754 and outputs the gain coefficient as the first gain G1. The first gain coefficient calculation unit 756 applies the HPF only for a time corresponding to the time constant of the thermal response, and decreases the gain coefficient or stops the HPF, that is, sets the gain coefficient to zero, at other times. Overcorrection of the first gain G1 can be prevented, and the reliability of the response compensation processing can be improved.

[0077] Fig. 12-1 is a diagram showing an example of an input / output relationship of the first gain coefficient calculation unit 756. In Fig. 12-1, a horizontal axis represents the counter C, that is, time, and a vertical axis represents the first gain G1. The first gain G1 has a predetermined value when the counter C is 0 to C1, and when the counter C exceeds C1, the first gain G1 decreases linearly and becomes zero.

[0078] For example, the numerator C1 is the number of processing periods corresponding to an assumed time constant of temperature change. For example, if the processing period is 0.1 seconds and the assumed time constant of temperature change is 10 seconds, C1 is equal to 100.

[0079] TA_SelSw, which is the output of the state determination unit 750, and the pre-correction temperature TAin are input to the post-state change temperature difference calculation unit 755. The post-state change temperature difference calculation unit 755 outputs the changed temperature after the state change to the second gain coefficient calculation unit 757. Specifically, the post-state change temperature change calculation unit 755 stores a temperature T1 at the time of the state change as an internal variable and records the pre-correction temperature TAin as the state change temperature Ts each time the relationship of the previously described Expression 4 is satisfied. If the temperature Ts at the time of the state change is generalized, it can be referred to as a signal at the time of the state change.The temperature Ts at the time of the state change is stored in a temporary storage unit, for example, the RAM of the microcomputer 415. The post-state change temperature difference calculation unit 755 outputs, as a temperature difference Td, a difference between the temperature Ts at the time of the state change and the post-correction temperature TAin to the second gain coefficient calculation unit 757.

[0080] The second gain coefficient calculation unit 757 determines a gain coefficient based on a temperature difference value output from the post-state change calculation unit 755 and outputs the gain coefficient as the second gain G2. The second gain coefficient calculation unit 757 applies the HPF only to a temperature difference range that may occur due to the thermal response of the intake air temperature, and sets the gain coefficient to zero for other temperature differences. Overcorrection can be prevented by the second gain G2, and the reliability of the response compensation processing can be improved.

[0081] Fig. 12-2 is a diagram showing an example of an input / output relationship of the second gain coefficient calculation unit 757. In Fig. 12-2, a horizontal axis represents the temperature difference Td and a vertical axis represents the second gain G2. The second gain G2 increases monotonically when a temperature difference Td1 is Td0 to Td1, and the second gain G2 becomes a constant value when the temperature difference exceeds Td1.

[0082] According to the above-described embodiment, the following actions and effects can be achieved.

[0083] (1) The physical quantity detecting device 300 includes: the temperature sensor 453 that detects a temperature of the measurement target fluid 30 and outputs a signal corresponding to the post-correction temperature TAin; the compensation amount calculation unit 710 that calculates a derivative compensation amount used in the derivative compensation for the pre-correction temperature TAin by using the pre-correction temperature TAin; and the gain control unit 730 that adjusts the derivative compensation amount based on a deviation, which is a change in the derivative compensation amount over time. Thus, overcorrection due to the derivative compensation can be prevented. The effects are described in detail below.

[0084] Since the physical quantity detecting device 300 adjusts the phase-advance compensation amount based on the deviation, which is the change in the compensation amount over time calculated by the compensation amount calculation unit 710, correction can be applied according to the response state of the temperature sensor 453, thereby improving the response performance while preventing overcorrection. That is, when a response time is long, such as in air, phase-advance compensation is applied to increase the response speed. Conversely, when a water-cooled environment with a short response time or an abrupt signal change due to EMC noise occurs, overcorrection can be prevented by stopping the phase-advance compensation, thereby improving the accuracy of temperature measurement.

[0085] (2) When the deviation is equal to or greater than a predetermined value, the output Dd of the deviation determination unit 720 is "true" and a stop command is received from the timer unit 721; thus, the gain control unit 730 sets the derivative compensation amount to zero. Thus, overcorrection can be largely prevented by setting the compensation amount to zero in an overcorrection state where the deviation is large.

[0086] (3) The deviation that the deviation determination unit 720 evaluates is a value subjected to moving average processing by the moving average filter 722. Thus, an influence of noise included in the pre-correction temperature TAin can be reduced.

[0087] (4) The gain control unit 730 includes the state determination unit 750 for determining the state of the temperature sensor 453 using the post-correction temperature TAin and performing gain control to adjust the amount of derivative compensation. Thus, the correction is applied according to the state of the temperature sensor 453, and the responsiveness can be improved while preventing overcorrection.

[0088] (5) The microcomputer 415 includes the noise reduction processing unit 740 for reducing output noise of the post-correction temperature TAout. As shown in Fig. 10, the state selection unit 753 determines the state of the temperature sensor 453 based on a result of the determination made by the response compensation amount determination unit 752 using the amount of delay that occurs due to the noise attenuation processing unit 740, that is, the determination result of the LPF delay determination unit 751, and the derivative compensation amount.

[0089] (6) The determination based on the derivative compensation amount performed by the reaction compensation amount determination unit 752 is a determination of a magnitude relationship between the compensation amount and the threshold value with the hysteresis characteristic as shown in Fig. 9. If the threshold value does not have the hysteresis characteristic and is a predetermined constant value, the response compensation amount may change in a certain HPF constant setting due to a slight change in the output of the temperature sensor 453 caused by an influence of a calculation error, and the response compensation amount may exceed the threshold value in a short time. However, such a problem can be prevented because the threshold value has the hysteresis characteristic as shown in Expressions 3 and 4.

[0090] (7) The microcomputer 415 includes: the post-state change elapsed time calculation unit 754, which includes the storage unit that stores, as a signal at the time of the state change, the post-correction temperature TAin, which is a detection signal when the state of the temperature sensor 453 changes; and the first gain coefficient calculation unit 756, which determines the first gain G1 used by the gain control unit 730 according to a difference between the last pre-correction temperature TAin and the signal at the time of the state change. Thus, the HPF can be applied only to a temperature difference range that may occur due to the thermal response of the intake air temperature, and the gain coefficient can be set to zero for other temperature differences, thereby preventing over-correction and improving the reliability of the response compensation processing.

[0091] (8) The microcomputer 415 includes the second gain coefficient calculation unit 757, which determines the second gain G2 used by the gain control unit 730 according to a time elapsed from a time when the state of the temperature sensor 453 changes. Thus, the HPF can be applied only for the time corresponding to the time constant of the thermal response, and at other times, the gain coefficient can be reduced or the gain coefficient can be set to zero, thereby preventing overcorrection and improving the reliability of the response compensation processing.

[0092] (9) The compensation amount calculation unit 710 sets a different gain for each case where the pre-correction temperature TAin increases and the case where the pre-correction temperature TAin decreases. Thus, it is possible to cope with a case where the time constant in the output of the temperature sensor 453 differs between the thermal response on a heating side and the thermal response on a cooling side.

[0093] (10) The physical quantity detecting device 300 includes the flow rate detecting circuit 601 that detects the flow rate of the measurement target fluid 30. The compensation amount calculating unit 710 changes the gain of the HPF based on the obtained AveQ by adjusting the flow rate characteristic of the pre-correction flow rate FAin, which is the output of the flow rate detecting circuit 601, as shown in Fig. 5. For example, the influence of heat conduction becomes relatively large in a lower flow rate range where the influence of heat transfer from the intake air decreases, and the response delay of the pre-correction temperature TA increases. Response compensation according to the time constant can be achieved by determining the gains according to the flow rate.

[0094] (11) The physical quantity detecting device 300 corrects the temperature characteristic of the flow rate detecting circuit 601 using the temperature of the temperature sensor 453 corrected by a correction processing unit, that is, the post-correction temperature TAout. Thus, the flow rate at the time of thermal reaction can be calculated with high accuracy.

[0095] (12) A physical quantity detecting sensor, the compensation amount calculating unit, and the gain control unit are mounted on the same board formed of a glass epoxy resin. In the board formed of the glass epoxy resin, the thermal response deteriorates significantly; however, the board formed of the glass epoxy resin is inexpensive and easy to process, which is advantageous. Thus, by using the microcomputer 415 with the configuration of the present embodiment or the like, even when the board formed of the glass epoxy resin is used, the problem of thermal response can be eliminated and the manufacturing cost of the physical quantity detecting device 300 can be reduced. (Modified Example 1)

[0096] The microcomputer 415 does not need to include the timer unit 721. Fig. Figure 13 shows a functional block diagram of the microcomputer 415, which does not include the timer unit 721. Furthermore, Fig. 13, a deviation calculation unit 723 is arranged instead of the deviation determination unit 720. TA_mva, which is the output of the moving average filter 722, is input to the deviation calculation unit 723. The deviation calculation unit 723 calculates a deviation, which is the amount of change in TA_mva, which is the input value, over time, and outputs the deviation as DT to a third gain coefficient calculation unit 758, as described below.

[0097] In the present modified example, the output of the state determination unit 750 is input to the gain control unit 730.

[0098] Fig. 14 shows a functional block diagram of the gain control unit 730 in Modified Example 1.

[0099] In the present modified example, the third gain coefficient calculation unit 758 is added to the configuration of the embodiment. The third gain coefficient calculation unit 758 determines and outputs a third gain G3 based on the value output from the deviation calculation unit 723. The third gain coefficient calculation unit 758 applies the HPF only to a deviation range that may occur due to the thermal response of the intake air temperature, and sets the gain coefficient to zero for other deviations. Overcorrection by the third gain G3 can be prevented, and the reliability of the response compensation processing can be improved.

[0100] Fig. 15 is a diagram showing an example of an input / output relationship of the third gain coefficient calculation unit 758. In Fig. 15, a horizontal axis represents the deviation DT and a vertical axis represents the third gain G3. The third gain G3 has a predetermined value when the deviation DT is 0 to DT1, decreases linearly when the deviation DT exceeds DT1, and becomes zero when the deviation DT exceeds DT2.

[0101] The gain control unit 730 multiplies TA_mva, which is the output value of the moving average filter 722, by the first gain G1, the second gain G2, and the third gain G3, and outputs a product thereof as TAadd. Thus, when the output DT of the deviation calculation unit exceeds DT2, TAadd becomes zero because the third gain G3 is zero. As described above, even if the counter unit 721 is not provided, the same actions and effects as those of the embodiment can be achieved. (Modified Example 2)

[0102] In the embodiment described above, the correction target is temperature; however, the correction targets can be different physical quantities. Fig. Fig. 16 shows a functional block diagram of the microcomputer 415 when correcting an output value of a humidity sensor and Fig. Figure 17 shows a functional block diagram of the microcomputer 415 when correcting an output value of a flow sensor. However, in this case, the gain of the compensation amount calculation unit 710 is set to a certain constant value. Since the correction target in the embodiment is temperature, the flow rate signal, which affects temperature, is also used as shown in Fig. 4; however, the flow rate signal is not necessarily required for humidity or flow rate correction. Other measurement quantities are shown in Fig. 16 or Fig. 17 not described.

[0103] That is, the present invention can be implemented by using only a measured value of a single physical quantity detecting element and a value calculated using the measured value, and other physical quantity detecting elements are not essential. That is, an additional sensor for correction is not essential, and thus the physical quantity detecting device can be downsized. (Modified Example 3)

[0104] In the above-described embodiment, the compensation amount calculation unit 710 again sets the output TAhp to zero when receiving the stop command from the timer unit 721. However, instead of setting the output TAhp to zero when receiving the stop command from the timer unit 721, the compensation amount calculation unit 710 may calculate the compensation amount with a smaller gain of the high-pass filter than usual and output the output TAhp that is not zero. (Modified Example 4)

[0105] In the above-described embodiment, the deviation determination unit 720 and the timer unit 721 need not be provided. In this case, the output TAhp of the compensation amount calculation unit 710 does not need to become zero by the stop command from the timer unit 721, but similar effects of the embodiment can be achieved by the operations of the state determination unit 750 and the gain control unit 730. (Modified Example 5)

[0106] The device 300 for detecting physical quantities need not include the on-board temperature sensor 423 or the relative humidity sensor 422.

[0107] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design changes may be made. For example, the above-described embodiments were described in detail in order to describe the present invention in an easily understandable manner, and the present invention is not necessarily limited to the configurations described above. Furthermore, various modified examples may be combined. List of reference symbols 30 Target fluid 300 Device for recording physical quantities 400 circuit boards 415 microcomputers 453 Temperature sensor 601 Flow rate detection circuit 710 Compensation quantity calculation unit 720 Deviation Determination Unit 721 Timer Unit 722 moving average filter 723 Deviation calculation unit 730 Gain control unit 731 Addition processing unit 740 Noise Attenuation Processing Unit 750 condition determination unit 751 LPF deceleration determination unit 752 Reaction compensation quantity determination unit 753 State selection unit 754 Unit for calculating the time elapsed after a change of state 755 Unit for calculating the temperature difference after a change of state 756 Unit for calculating the first gain coefficient 757 Unit for calculating the second gain coefficient 758 Unit for calculating the third gain coefficient 760 Flow characteristic adjustment unit

Claims

[1] Device for detecting physical quantities (300), comprising: a physical quantity sensor (453) that detects a physical quantity of a measurement target fluid (30) and outputs a detection signal; a compensation amount calculation unit (710) that calculates, by using the detection signal, a derivative compensation amount used in derivative compensation for the detection signal, the derivative compensation being for improving the thermal response characteristic by phase-lead compensation using a high-pass filter; and a gain control unit (730) that adjusts the lead compensation amount based on a deviation that is an amount of change in the lead compensation amount over time. [2] The physical quantity detecting device (300) according to claim 1, wherein the gain control unit (730) sets the derivative compensation amount to zero when the deviation is equal to or greater than a predetermined value. [3] The physical quantity detecting apparatus (300) according to claim 1, wherein the deviation uses a moving average of the lead compensation amount. [4] The physical quantity detecting device (300) according to claim 1, wherein the gain control unit (730) adjusts the derivative action compensation amount by using a result of determining a state of the physical quantity detecting sensor (453) by using the detection signal. [5] The physical quantity detecting device (300) according to claim 4, further comprising a noise attenuation processing unit (740) for reducing the output noise of the physical quantity detecting sensor (453), wherein the state of the physical quantity detecting sensor (453) is determined based on an amount of delay occurring due to the noise attenuation processing unit (740) and the amount of lead compensation. [6] The physical quantity detecting apparatus (300) according to claim 5, wherein the determination based on the derivative compensation amount is a determination of a magnitude relationship between the derivative compensation amount and a threshold value having a hysteresis characteristic. [7] Apparatus for detecting physical quantities (300) according to claim 5, further comprising: a storage unit that stores, as a signal at a time of state change, the detection signal when the state of the sensor (453) for detecting physical quantities changes; and a first gain coefficient calculation unit (756) that determines a first gain used by the gain control unit (730) according to a difference between a last detection signal and the signal at the time of the state change. [8] The physical quantity detecting device (300) according to claim 5, further comprising a second gain coefficient calculating unit (757) that determines a second gain used by the gain controlling unit (730) according to an elapsed time from a time when the state of the physical quantity detecting sensor (453) has changed. [9] The physical quantity detecting device (300) according to claim 1, wherein the compensation amount calculating unit (710) sets a different gain for a case where the detection signal increases and a case where the detection signal decreases, respectively. [10] The physical quantity detecting device (300) according to claim 1, further comprising a flow rate sensor that detects a flow rate of the measurement target fluid (30), wherein the physical quantity is a temperature, and the compensation amount calculating unit (710) changes a gain used to calculate the derivative compensation amount based on an output of the flow rate sensor. [11] The physical quantity detecting device (300) according to claim 10, wherein a temperature characteristic of the flow rate sensor is corrected by using a temperature of the flow rate sensor corrected using a derivative compensation amount adjusted by the gain control unit (730). [12] The physical quantity detecting device (300) according to claim 1, wherein the physical quantity detecting sensor, the compensation amount calculating unit (710) and the gain controlling unit (730) are mounted on the same board formed of a glass epoxy resin.

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