WO2023100294A1 - Control device for internal combustion engine - Google Patents

Control device for internal combustion engine Download PDF

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Publication number
WO2023100294A1
WO2023100294A1 PCT/JP2021/044124 JP2021044124W WO2023100294A1 WO 2023100294 A1 WO2023100294 A1 WO 2023100294A1 JP 2021044124 W JP2021044124 W JP 2021044124W WO 2023100294 A1 WO2023100294 A1 WO 2023100294A1
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WIPO (PCT)
Prior art keywords
value
internal combustion
combustion engine
transient state
flow rate
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PCT/JP2021/044124
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French (fr)
Japanese (ja)
Inventor
広人 石川
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日立Astemo株式会社
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Priority to PCT/JP2021/044124 priority Critical patent/WO2023100294A1/en
Publication of WO2023100294A1 publication Critical patent/WO2023100294A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
    • 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

Definitions

  • the present invention relates to a control device for an internal combustion engine.
  • the flow rate of air drawn into the internal combustion engine is measured by a flow sensor installed in the intake pipe of the internal combustion engine, and the amount of air charged into the cylinder is calculated based on the measured intake air amount.
  • a control technique for an internal combustion engine is known that controls the fuel injection amount and ignition timing according to the calculated air amount.
  • the detection error of the flow sensor increases. Therefore, a technique for correcting the flow sensor error based on the pulsation amplitude has been disclosed (for example, Patent Document 1).
  • an acceleration judgment threshold value is set from the flow rate average value, and acceleration is judged when the flow rate instantaneous value exceeds this threshold.
  • the acceleration determination threshold value must be set large, and there is a problem that slow acceleration cannot be appropriately determined.
  • An object of the present invention is to provide a control device for an internal combustion engine that can ensure the accuracy of determination of a transient state and can appropriately correct the output value of the flow rate sensor according to the pulsation width.
  • the control device for an internal combustion engine of the present invention sets at least one crank angle for determining a transient state indicating the timing for determining a transient state of the output value of the flow rate sensor for each rotation speed of the internal combustion engine. Then, at least one threshold value for determining a transient state is set from the output value of the flow rate sensor, and the output value of the flow rate sensor at the crank angle for determining a transient state is compared with the threshold value for determining a transient state.
  • the output value of the flow rate sensor is corrected according to the pulsation width of the output value of the flow rate sensor, and if the state is the transient state, the output of the flow rate sensor.
  • a processor is provided for limiting correction of values.
  • FIG. 1 is a schematic configuration diagram of an entire system of an engine control device according to an embodiment of the present invention
  • FIG. FIG. 2 is a diagram for explaining an operating region in which EGR is introduced in an operating region defined by the rotational speed and charging efficiency of an internal combustion engine
  • FIG. 2 is a diagram for explaining an operating region in which a Miller cycle is performed in an operating region defined by the rotational speed and charging efficiency of an internal combustion engine
  • FIG. 5 is a diagram for explaining an intake/exhaust valve lift pattern that realizes a late-closing mirror cycle
  • FIG. 4 is a diagram for explaining an intake/exhaust valve lift pattern that realizes an early closing mirror cycle
  • It is a figure explaining the intake pulsation behavior of a flow sensor part.
  • FIG. 4 is a diagram for explaining the relationship between average flow velocities in a bypass channel and a main channel in different pulsating flows;
  • FIG. 4 is a diagram for explaining a pulsation correction map for correcting a flow rate sensor detection error caused by a pulsation phenomenon;
  • It is a figure which shows the acceleration determination threshold value set based on the flow sensor detected value, an average value, and an average value.
  • It is a figure which shows a pulsation amplitude.
  • pulsation-amplitude-ratio erroneous detection It is a figure explaining an acceleration determination principle. It is a figure explaining the detail of acceleration determination.
  • FIG. 1 is a schematic configuration diagram of the entire system of the engine control device.
  • the engine control device includes an internal combustion engine 1, a flow rate sensor 2 (airflow sensor), a turbocharger 3, an air bypass valve 4, an intercooler 5, a supercharging temperature sensor 6 (temperature sensor), a throttle valve 7, an intake manifold 8, Boost pressure sensor 9 (pressure sensor), flow enhancement valve 10, intake valve 11, exhaust valve 13, fuel injection valve 15, spark plug 16, knock sensor 17, crank angle sensor 18, waste gate valve 19, air-fuel ratio sensor 20 , an exhaust purification catalyst 21 , an EGR (Exhausted Gas Recirculation) pipe 22 , an EGR cooler 23 , an EGR valve 24 , a temperature sensor 25 , a differential pressure sensor 26 and an ECU (Electronic Control Unit) 27 .
  • EGR Extra Gas Recirculation
  • the turbocharger 3 includes a compressor 3a and a turbine 3b.
  • the compressor 3a is connected to an intake passage, and the turbine 3b is connected to an exhaust passage.
  • the turbine 3b of the turbocharger 3 converts the energy of the exhaust gas from the internal combustion engine 1 into rotational energy of turbine blades.
  • the compressor 3a of the turbocharger 3 compresses the intake air that has flowed in from the intake passage by rotating the compressor blades connected to the turbine blades.
  • the intercooler 5 is provided downstream of the compressor 3a of the turbocharger 3, and cools the temperature of the intake air that has been adiabatically compressed by the compressor 3a.
  • the supercharging temperature sensor 6 is installed downstream of the intercooler 5 and measures the temperature of the intake air cooled by the intercooler 5 (supercharging temperature).
  • the throttle valve 7 is provided downstream of the supercharging temperature sensor 6, throttles the intake passage, and controls the amount of intake air flowing into the cylinder of the internal combustion engine 1.
  • the throttle valve 7 is composed of an electronically controlled butterfly valve capable of controlling the degree of opening of the valve independently of the amount of depression of the accelerator pedal by the driver.
  • An intake manifold 8 to which a supercharging pressure sensor 9 is assembled is in communication with the downstream side of the throttle valve 7 .
  • the intake manifold 8 provided downstream of the throttle valve 7 and the intercooler 5 may be integrated. In this case, since the volume from the downstream of the compressor 3a to the cylinder can be reduced, it is possible to improve the responsiveness of acceleration and deceleration.
  • the flow enhancement valve 10 is arranged downstream of the intake manifold 8 and enhances the turbulence of the flow inside the cylinder by creating a drift in the intake air.
  • the internal combustion engine 1 has an intake valve 11 and an exhaust valve 13 .
  • the intake valve 11 and the exhaust valve 13 each have a variable valve mechanism for continuously varying the valve opening/closing phase.
  • a cylinder of the internal combustion engine 1 is provided with a direct fuel injection valve 15 that injects fuel directly into the cylinder.
  • the fuel injection valve 15 may be of a port injection type that injects fuel into the intake port.
  • a spark plug 16 is assembled to the cylinder of the internal combustion engine 1, with an electrode portion exposed inside the cylinder and igniting a combustible air-fuel mixture by a spark.
  • the knock sensor 17 is provided in the cylinder block and detects the presence or absence of knock occurring within the combustion chamber.
  • the crank angle sensor 18 outputs a signal corresponding to the rotation angle of the crankshaft as a signal indicating the rotation speed of the crankshaft to the ECU 27, which will be described later, in each combustion cycle.
  • the air-fuel ratio sensor 20 is provided downstream of the turbine 3b of the turbocharger 3, and outputs a signal indicating the detected oxygen concentration, ie, the air-fuel ratio, to the ECU 27.
  • the exhaust purification catalyst 21 is provided downstream of the air-fuel ratio sensor 20, and purifies harmful exhaust gas components such as carbon monoxide, nitrogen compounds, and unburned hydrocarbons in the exhaust gas by catalytic reaction.
  • the turbocharger 3 is equipped with an air bypass valve 4 and a wastegate valve 19 .
  • the air bypass valve 4 is arranged on a bypass flow path connecting upstream and downstream of the compressor 3a in order to prevent the pressure from downstream of the compressor 3a to upstream of the throttle valve 7 from excessively increasing.
  • the air bypass valve 4 is opened under the control of the ECU 27, so that the compressed intake air in the downstream portion of the compressor 3a passes through the bypass passage to the compressor. It flows back to the upstream part of 3a. As a result, it becomes possible to lower the supercharging pressure.
  • the wastegate valve 19 is arranged on a bypass flow path that connects upstream and downstream of the turbine 3b.
  • the wastegate valve 19 is an electrically operated valve whose valve opening degree can be freely controlled with respect to the supercharging pressure under the control of the ECU 27 .
  • the opening degree of the waste gate valve 19 is adjusted by the ECU 27 based on the supercharging pressure detected by the supercharging pressure sensor 9, part of the exhaust gas passes through the bypass flow path, thereby supplying the exhaust gas to the turbine 3b. work can be reduced. As a result, the boost pressure can be maintained at the target pressure.
  • the EGR pipe 22 communicates with an exhaust passage downstream of the exhaust purification catalyst 21 and an intake passage upstream of the compressor 3a, and divides the exhaust gas from the downstream of the exhaust purification catalyst 21 to the upstream of the compressor 3a. Reflux to An EGR cooler 23 provided in the EGR pipe 22 cools the exhaust gas.
  • the EGR valve 24 is provided downstream of the EGR cooler 23 and controls the flow rate of exhaust gas.
  • the EGR pipe 22 is provided with a temperature sensor 25 that detects the temperature of the exhaust gas upstream of the EGR valve 24 and a differential pressure sensor 26 that detects the differential pressure between upstream and downstream of the EGR valve 24 .
  • the ECU 27 has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls each component of the engine control device and executes various data processing. circuit. Various sensors and various actuators described above are connected to the ECU 27 .
  • CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the ECU 27 controls the operations of actuators such as the throttle valve 7, fuel injection valve 15, intake and exhaust valves with variable valve mechanism (intake valve 11 and exhaust valve 13), EGR valve 24, and the like.
  • the ECU 27 also detects the operating state of the internal combustion engine 1 based on signals input from various sensors, and ignites the spark plug 16 at a timing determined according to the operating state.
  • FIG. 2 shows an operating region in which EGR is introduced in an operating region defined by the rotational speed of the internal combustion engine and the charging efficiency (the ratio of the mass of air drawn into the cylinder in one cycle to the mass of air in the standard state equivalent to the cylinder volume). It is a figure explaining.
  • the operating range of an internal combustion engine is roughly divided into a non-supercharging range and a supercharging range. In the non-supercharging region, the charging efficiency is controlled by the throttle valve, and in the supercharging region, the charging efficiency is controlled by opening the throttle valve and controlling the supercharging pressure by the waste gate valve.
  • the internal combustion engine shown in this embodiment is equipped with an EGR system.
  • EGR cooled by an EGR cooler is recirculated to the cylinder from a relatively high load condition in the non-supercharging region of the internal combustion engine to a supercharging region, thereby diluting the gas sucked into the cylinder with the inert gas EGR.
  • knock improper combustion known as knock, which tends to occur under high load conditions. Since knocking can be suppressed, the ignition timing can be controlled to advance appropriately, and fuel-efficient operation can be realized.
  • FIG. 3 is a diagram explaining an operating region in which the Miller cycle is performed in an operating region defined by the rotational speed and charging efficiency of the internal combustion engine.
  • the throttle valve In the relatively low flow rate operating region of the internal combustion engine, the throttle valve is controlled to be more closed in order to reduce the amount of air drawn into the cylinder. This tends to increase pump losses.
  • the piston compression work can be reduced and the Miller cycle can be realized.
  • the amount of intake air is controlled by controlling the phase of the intake valve instead of the throttle valve, the throttle valve can be set to the open side and the pump loss can be reduced.
  • the effect of the Miller cycle and the effect of reducing pump loss make it possible to achieve fuel-efficient operation.
  • FIGS. 4A and 4B are diagrams for explaining the intake and exhaust valve lift patterns that realize the late closing mirror cycle and the early closing mirror cycle, respectively. If the intake valve closing timing is set to be earlier or later than the bottom dead center by varying the intake valve phase, the amount of air taken into the cylinder increases or decreases. In the late-closing Miller cycle, the amount of air taken into the cylinder is suppressed by blowing back the gas once taken into the cylinder into the intake pipe after the bottom dead center.
  • the intake valve phase variable mechanism is adopted to realize the Miller cycle, but the intake valve lift switching mechanism or the phase/lift continuously variable mechanism may be adopted to realize the Miller cycle. It is possible.
  • FIG. 5 is a diagram for explaining the intake pulsation behavior and the pulsation amplitude ratio of the flow rate sensor section when the Miller cycle and EGR are performed. Since the internal combustion engine intermittently takes air only during the intake stroke of each cylinder, pulsation occurs in the intake pipe. In particular, in the low rotation/high load region, there is a tendency for pulsation with a large pulsation amplitude ratio to occur at low frequencies, which is a factor that deteriorates the detection accuracy of the flow rate sensor.
  • the period and phase of the pulsation are synchronized with the rotational speed of the internal combustion engine. That is, the crank angle at which the maximum value or the minimum value is obtained is determined by the rotation speed of the internal combustion engine.
  • the pulsation amplitude ratio is defined as the value obtained by dividing the pulsation width, which is the difference between the maximum value and the minimum value of the inspiratory flow rate within a certain period, by the flow rate average value.
  • FIG. 6 is a diagram explaining the concept of the flow inside the flow sensor.
  • the flow sensor is provided with a bypass channel, and a sensor element for detecting the flow velocity is installed in the bypass channel. Adhesion of dust and water to the sensor element can be prevented by devising the shape of the bypass channel.
  • the flow sensor By detecting the amount of heat released by the local flow of the sensor element, the flow sensor outputs a voltage signal corresponding to the main flow rate of the flow sensor mounting part.
  • the flow field shape (length L, l, inner diameter D, d), shape loss coefficients (Cp, cp), and friction loss coefficients (Cf, cf) differ between the main stream and the bypass flow. Therefore, the flow field is based on a different momentum equation.
  • FIG. 7 is a diagram explaining the relationship between the average flow velocity in the main flow path and the average flow velocity in the bypass flow path measured by the flow sensor for different pulsating flows.
  • the bypass flow path has a smaller inner diameter than the main flow path and has a curved shape, resulting in a large pressure loss.
  • the characteristics change depending on the frequency, the absolute value of the flow velocity, and the flow velocity direction due to drift in the main flow path, drift in the bypass flow path, resonance, response delay of the flow sensor, and the like.
  • a deviation occurs between the average value of the flow velocity in the bypass channel and the average value of the flow velocity in the mainstream, which are measured by the flow rate sensor. Therefore, correction means is required.
  • FIG. 8 is an example of a pulsation correction map that corrects the flow rate sensor detection error caused by the pulsation phenomenon.
  • a correction value is recorded in a map whose axes are the rotational speed of the internal combustion engine and the pulsation amplitude ratio described with reference to FIG.
  • the detected value of the flow sensor is corrected based on the corresponding correction amount (correction value) based on the pulsation amplitude ratio and the engine speed from the detected value of the flow sensor.
  • Figures 9A to 9C are diagrams for explaining the flow rate sensor detection value and the pulsation amplitude ratio during acceleration. Since the flow rate increases during acceleration (Fig. 9A), the pulsation amplitude defined as the difference between the maximum and minimum values of the flow rate within a certain period rises (Fig. 9B), and the pulsation amplitude ratio also rises (Fig. 9C). . Since the flow velocity in this case is not a pulsating flow, correction using the pulsation correction map described with reference to FIG. 8 results in unintended correction.
  • the graph in FIG. 9A shows the flow rate average value and the acceleration determination threshold value set based on the flow rate average value. As shown in this figure, when the pulsation amplitude ratio in the steady state before acceleration is large, it is necessary to set the acceleration determination threshold value large so as not to erroneously determine acceleration during steady state. Acceleration cannot be determined in this case.
  • FIG. 10 is a diagram for explaining transient detection, taking acceleration as an example. The case of acceleration and the case of continuation of steady state are overwritten. There is a difference between the two at the timing indicated by the arrow, that is, the timing at which the flow rate becomes minimum when steady state continues, and it is possible to determine acceleration even if the instantaneous flow rate value does not increase much. As described with reference to FIG. 5, the timing at which the flow rate reaches its maximum or minimum is determined by the rotation speed of the internal combustion engine, so this timing can also be determined for each rotation speed of the internal combustion engine. A similar determination can be made during deceleration.
  • FIG. 11 is a diagram explaining an example of a method for determining the acceleration determination threshold. Similar to FIG. 10, the case of acceleration and the case of continuation of steady state are overwritten.
  • the threshold value used for acceleration determination is set by adding an additional value to the minimum value. It may be set based on the pulsation width, or may be set using a map based on the rotation speed of the internal combustion engine and the average flow rate. Besides the minimum value, an average value, a maximum value, or the like may be selected as the reference value.
  • FIG. 12 is a block diagram explaining the pulsation correction logic of the flow rate sensor mounted on the ECU. First, the principle of the hot-wire airflow sensor used in the flow sensor will be explained.
  • a hot-wire airflow sensor has a heating resistor placed in the airflow to be measured as its main component.
  • a bridge circuit is constructed so that the amount of air decreases when the amount is small, and the amount of air is taken out as a voltage signal from the current flowing through the heating resistor.
  • the analog voltage signal output from the flow sensor is converted into a digital signal by an A/D converter.
  • the digital voltage signal is converted into a flow rate signal using a voltage/flow rate conversion table.
  • the voltage signal corresponding to the air volume is output as a voltage value, but there is also a method in which the voltage signal is converted to a frequency signal by a voltage-frequency conversion circuit and output. be.
  • the period of the frequency signal is measured at the port input of the CPU, and the period or the value converted from the period to the frequency is derived, and this period or frequency is converted into a detected air amount by searching and interpolating the values of the air amount conversion table stored in advance in the ROM.
  • B1202 shows the relationship between the amount of intake air and the output signal of a general hot-wire air flow sensor.
  • the characteristic curve has a non-linear relationship with increasing voltage.
  • the non-linear characteristic is used because the following equation, called King's equation, is mainly used for the amount of air Q when converting the detection signal from the heating resistor into the amount of air.
  • Ih ⁇ Rh ( ⁇ + ⁇ ⁇ ⁇ Q) ⁇ (Th - Ta)
  • Ih is the current value of the heating resistor
  • Rh is the resistance value of the heating resistor
  • Th is the surface temperature of the heating resistor
  • Ta is the air temperature
  • Q is the air volume
  • ⁇ and ⁇ are constants determined by the specifications of the heating resistor. is.
  • the current value Ih of the heating resistor is controlled so that (Th ⁇ Ta) is constant, so the amount of air is detected by converting it into a voltage value V due to the voltage drop across the resistor.
  • the value V becomes a quartic function expression. Therefore, the curvature of the quartic curve, that is, the relationship between the output and the air amount becomes non-linear when converting to the air amount.
  • the rotational speed of the internal combustion engine is calculated based on the crank angle sensor signal.
  • a period for detecting feature amounts such as maximum/minimum/average values from the rotation speed is determined.
  • the period for detecting the feature amount is determined by the rotation speed and the number of cylinders, but it may be set for each predetermined crank angle.
  • B1205 the timing for judging acceleration/deceleration is set.
  • the crank angle at which the flow rate is minimized for each rotational speed is set as the acceleration determination timing, and the crank angle at which the flow rate is maximized is set as the deceleration determination timing.
  • the maximum value, minimum value, and average value within the feature amount detection period are calculated.
  • a threshold for acceleration/deceleration determination is calculated based on the detected maximum and minimum values.
  • the threshold for acceleration is the value obtained by subtracting the minimum value from the maximum value with the minimum value as the reference, and a fixed ratio of the pulsation width is added.
  • the threshold for deceleration is the constant pulsation width with the maximum value as the reference. The value obtained by subtracting the ratio.
  • a lower limit value is provided for the value to be added or subtracted so as not to misjudge a slight change in flow rate as acceleration/deceleration when the pulsation width is small.
  • the threshold value and the flow rate are compared at the acceleration/deceleration determination timing to determine whether the acceleration/deceleration state or the steady state.
  • the pulsation amplitude ratio is calculated from the detected maximum/minimum/average values.
  • B1210 derives the correction amount for each of the steady state and the transient state. In the steady state, the correction amount is calculated from the pulsation amplitude ratio and the rotational speed as described with reference to FIG. It is set to a value such as 1.0, for example, to stop the correction during transition.
  • the air flow rate is corrected based on the pulsation amplitude ratio pre-correction air amount and the pulsation correction amount. In this way, by limiting the function to correct the pulsation error to normal operation and switching the correction amount during transient operation, the accuracy of the flow sensor is always ensured even under operating conditions that tend to cause flow sensor error due to pulsation. Since the accuracy of air-fuel ratio control is improved by not performing unnecessary correction, deterioration of exhaust gas can be prevented.
  • FIG. 13 is a diagram explaining a flow chart of pulsation correction of the flow rate sensor. The processing shown in the figure is executed at every constant crank angle, for example, every 6 degrees.
  • the flow sensor output value is A/D converted.
  • the A/D converted voltage value is converted into a flow rate.
  • the maximum and minimum values for calculating the pulsation amplitude ratio are updated.
  • the flow rate is integrated for calculating the average value. Transient judgment is performed in S1305. Details will be described with reference to FIG. In S1306, it is determined whether or not the crank angle is a predetermined value.
  • the predetermined crank angle is, for example, the compression top dead center of each cylinder. If it is determined to be the predetermined crank angle, the processing of S1307 to S1310 is performed.
  • the flow rate average value is calculated from the flow rate integrated value obtained at S1304.
  • the pulsation amplitude ratio is calculated from the maximum/minimum value obtained in S1303 and the flow average value obtained in S1307.
  • a correction amount to be used in a steady state is calculated from the pulsation amplitude ratio and the rotation speed.
  • the maximum value, minimum value, and integrated flow rate value are initialized to prepare for the next calculation.
  • S1311 it is determined whether or not the state is in a transient state. If the state is in a transient state, the correction value is set to 1.0 in S1312. In S1314, the flow rate is corrected to be the final output.
  • FIG. 14 is a diagram explaining a flow chart of transient determination. This processing is the processing content of S1305 in FIG. Acceleration/deceleration is determined in S1401. Details will be described with reference to FIG. In S1402, it is determined whether or not the determination of acceleration or deceleration is established in S1401. If the determination of acceleration or deceleration is established, the processing of S1403 to S1404 is performed. conduct.
  • the transient state is set to be established (the flag indicating the transient state is turned on), and the steady counter is initialized to 0 in S1404.
  • 1 is added to the steady counter.
  • the transient state is set to not established (the flag indicating the transient state is turned off) in S1407.
  • FIG. 15 is a diagram for explaining a flowchart of acceleration/deceleration determination. This processing is the processing content of S1401 in FIG. In S1501, the maximum and minimum values for acceleration determination are updated. In S1502, the maximum and minimum values for deceleration determination are updated. In S1503, the crank angle for determining acceleration/deceleration is set.
  • an acceleration determination threshold value is calculated.
  • the acceleration determination threshold is obtained by adding an additional value based on the minimum value for acceleration determination as described with reference to FIG. 11, and the additional value is obtained by multiplying the pulsation width by a coefficient.
  • the coefficient is set for each operating state such as rotation speed.
  • a lower limit value is set for the additional value.
  • the lower limit value is, for example, a value obtained by multiplying the minimum value by a coefficient.
  • a deceleration determination threshold value is calculated.
  • the deceleration determination threshold value is obtained by subtracting a subtraction value based on the maximum value for deceleration determination, and the subtraction value is obtained by multiplying the pulsation width by a coefficient.
  • the coefficient is set for each operating state such as rotation speed. Also, when the pulsation width is small, the subtraction value becomes small, which may cause an erroneous determination. Therefore, a lower limit value is set for the subtraction value.
  • the lower limit value is, for example, a value obtained by multiplying the maximum value by a coefficient. This coefficient is also set for each operating state. In S1515, the maximum and minimum values are initialized for the next determination.
  • FIG. 16 is a diagram showing the effects of the embodiment of the present invention.
  • the upper part of FIG. 16 shows the flow rate sensor detection value, the average value, and the acceleration determination threshold value set based on the average value described in FIG. 9A overlaid with the acceleration determination threshold value according to the present embodiment.
  • the acceleration determination is performed for each determined crank angle, so the threshold is indicated by a circle instead of a line.
  • the threshold is set by adding 90% of the difference between the latest maximum and minimum values based on the minimum value. As shown in the figure, there is sufficient leeway to prevent an erroneous determination at the timing of acceleration determination in the steady state, and a threshold value can be set that enables prompt acceleration determination in acceleration.
  • the acceleration/deceleration threshold value is set based on the maximum value or the minimum value.
  • the present invention is not limited to this. may be used as a reference.
  • the configuration is such that the correction is stopped during a transition, the correction value may be limited.
  • a processor (CPU) of a control device (ECU 27, FIG. 1) for an internal combustion engine (engine) sets a transient state determination crank angle indicating the timing for determining a transient state of the output value of the flow rate sensor 2 for each rotation speed of the internal combustion engine. At least one is set (B1205, FIG. 12).
  • the processor (CPU) sets at least one transient state determination threshold value from the output value of the flow rate sensor 2 (B1207, FIG. 12).
  • the processor (CPU) compares the output value of the flow rate sensor 2 at the transient state determination crank angle with the transient state determination threshold to determine whether or not there is a transient state (B1208, FIG. 12).
  • the processor corrects the output value of the flow sensor 2 according to the pulsation width of the output value of the flow sensor 2 when it is not in a transient state (that is, in a steady state), and when it is in a transient state, the output value of the flow sensor (B1210, B1211, FIG. 12).
  • a transient state that is, in a steady state
  • the output value of the flow sensor B1210, B1211, FIG. 12
  • the processor calculates the pulsation amplitude ratio from the average value, the maximum value and the minimum value of the output value of the flow sensor 2 (B1209, FIG. 12), and the correction value corresponding to the combination of the pulsation amplitude ratio and the rotation speed (Fig. 8) is used to correct the output value of the flow sensor. As a result, errors in the output value of the flow rate sensor due to pulsation can be reduced.
  • the processor (CPU) sets the transient state determination crank angle to a crank angle at which the output value of the flow rate sensor 2 is larger than the average value or smaller than the average value in the steady state for each rotation speed. (FIGS. 5 and 10). For example, the processor (CPU) sets the crank angle for transient state determination to a crank angle at which the output value of the flow rate sensor 2 is maximized or minimized in a steady state for each rotation speed. As a result, erroneous determination of a transient state can be suppressed.
  • a processor sets a reference value (minimum value, maximum value, etc.) from the output value of the flow sensor 2 in a predetermined crank angle range, and sets a transient state determination threshold based on the reference value ( B1206, B1207, FIG. 12). Thereby, the transient state determination threshold value can be adjusted according to the output value (detected value) of the flow sensor.
  • the predetermined crank angle range is a crank angle range corresponding to a period synchronized with the intake interval or an integral multiple thereof.
  • the predetermined crank angle range is the period from one compression top dead center (TDC) to the next compression top dead center (S1306, FIG. 16).
  • TDC compression top dead center
  • S1306, FIG. 16 next compression top dead center
  • the output value of the flow sensor can include the maximum and minimum values due to pulsation.
  • the processor sets a value obtained by adding or subtracting a predetermined value to or from the reference value as the transient state determination threshold value (B1207, FIG. 12).
  • the reference value used in B1207 of FIG. 12 is the maximum or minimum output value of the flow rate sensor 2 within a predetermined crank angle range, but may be an average value. Thereby, the transient state determination threshold value can be adjusted according to the characteristic value of the distribution of the output value of the flow sensor.
  • the processor calculates a value obtained by multiplying the difference between the maximum value and the minimum value of the output value of the flow rate sensor 2 in a predetermined crank angle range by a first coefficient, and converts the calculated value to the predetermined value (addition value ) (S1505, FIG. 15).
  • the transient state determination threshold value can be adjusted according to the pulsation width.
  • a transient state is, for example, a state in which the intake flow rate transiently increases in response to an acceleration request.
  • the processor sets a value obtained by adding a predetermined value to the minimum value of the output value of the flow rate sensor 2 in a predetermined crank angle range as a transient state determination threshold value (acceleration determination threshold value) (B1207, Figure 12).
  • the processor determines that there is a transient state when the output value of the flow rate sensor 2 at the transient state determination crank angle is greater than the transient state determination threshold value (S1506: YES, S1507, FIG. 15). This improves the accuracy of determination of a transient state due to acceleration.
  • the transient state is, for example, a state in which the intake flow rate transiently decreases in response to a deceleration request.
  • the processor (CPU) sets a value obtained by subtracting a predetermined value from the maximum value of the output value of the flow rate sensor 2 in a predetermined crank angle range as a transient state determination threshold value (deceleration determination threshold value) (B1207, Figure 12). If the output value of the flow rate sensor 2 at the transient state determination crank angle is smaller than the transient state determination threshold value, the processor (CPU) determines that there is a transient state (S1512: YES, S1513, FIG. 15). This improves the accuracy of determining a transient state due to deceleration.
  • the processor calculates a value obtained by multiplying the maximum value or minimum value of the output value of the flow sensor 2 in a predetermined crank angle range by a second coefficient, and converts the calculated value to the predetermined value (addition value, subtraction value ) (S1505, S1511, FIG. 15). As a result, erroneous determination of a transient state can be suppressed when the pulsation width is small.
  • the present invention is not limited to the above-described embodiments, and includes various modifications.
  • the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.
  • part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
  • each of the above configurations, functions, etc. may be realized by hardware, for example, by designing a part or all of them with an integrated circuit.
  • each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function.
  • Information such as programs, tables, files, etc. that realize each function can be stored in memory, hard disks, SSD (Solid State Drives) and other recording devices, or IC cards, SD cards, DVDs and other recording media.
  • a control device for an internal combustion engine having a flow sensor for measuring a local flow rate of a flow in an intake pipe comprising: means for obtaining a correction value for correcting an output value of the flow sensor; means for setting at least one threshold value for determining a transient state based on the output value of the flow rate sensor; and an output value of the flow rate sensor at the crank angle for determining the transient state and the threshold value for determining the transient state. means for comparing the threshold value and determining a transient state, and means for calculating an intake air flow rate by switching the correction value of the flow rate according to a steady state or a transient state to correct the output value of the flow rate sensor.
  • a control device for an internal combustion engine comprising:
  • correction value for correcting the flow rate sensor output value is calculated from the pulsation amplitude ratio calculated from the average value, maximum value, and minimum value between predetermined crank angles and the engine speed. internal combustion engine controller.
  • the transient state determination crank angle is set to a crank angle at which the flow rate detected by the flow rate sensor in a steady state for each engine speed is larger than the average value or smaller than the average value.
  • the threshold value for determining the transient state is set by adding or subtracting a value calculated by multiplying the difference between the maximum value and the minimum value of the output value of the flow rate sensor between predetermined crank angles by a predetermined value to or from the reference value.
  • a control apparatus for an internal combustion engine according to any one of (2) to (7), wherein the predetermined crank angle interval is a period synchronized with an intake interval or an integral multiple thereof.
  • the exhaust gas property of the internal combustion engine due to the error in the correction value due to the erroneous detection of the pulsation that is a concern at the time of transition It is possible to prevent deterioration of fuel efficiency and deterioration of fuel efficiency.

Abstract

A processor (CPU) of a control device (ECU 27) for an internal combustion engine sets, for each rotation speed of the internal combustion engine, at least one crank angle for transient state determination that indicates the timing for determining the transient state of the output value of a flow rate sensor 2 (B1205). The processor sets at least one transient state determination threshold on the basis of the output value of the flow rate sensor 2 (B1207). The processor compares the output value of the flow rate sensor 2 at the crank angle for transient state determination with the transient state determination threshold to determine whether the output value is in a transient state (B1208). When the output value is not in the transient state, the processor corrects the output value of the flow rate sensor 2 in accordance with the pulsation width of the output value of the flow rate sensor 2, and when the output value is in the transient state, the processor limits the correction of the output value of the flow rate sensor (B1210, B1211).

Description

内燃機関の制御装置Control device for internal combustion engine
　本発明は、内燃機関の制御装置に関する。 The present invention relates to a control device for an internal combustion engine.
　従来から、内燃機関の吸気管内に組みつけられた流量センサにより内燃機関に吸入される空気流量を測定し、測定された吸入空気量にもとづいてシリンダ内に充填される空気量を演算し、上記演算された空気量に応じて燃料噴射量や点火時期を制御する内燃機関の制御技術が知られている。内燃機関に吸入される吸気の脈動が大きくなるにしたがって、流量センサの検出誤差が大きくなるために、脈動振幅にもとづいて流量センサ誤差を補正する技術が開示されている（たとえば特許文献１）。 Conventionally, the flow rate of air drawn into the internal combustion engine is measured by a flow sensor installed in the intake pipe of the internal combustion engine, and the amount of air charged into the cylinder is calculated based on the measured intake air amount. A control technique for an internal combustion engine is known that controls the fuel injection amount and ignition timing according to the calculated air amount. As the pulsation of the intake air taken into the internal combustion engine increases, the detection error of the flow sensor increases. Therefore, a technique for correcting the flow sensor error based on the pulsation amplitude has been disclosed (for example, Patent Document 1).
特開2014-020212号公報Japanese Patent Application Laid-Open No. 2014-020212 特開2018-031308号公報Japanese Patent Application Laid-Open No. 2018-031308
　しかしながら、スロットルバルブを開くなど内燃機関に吸入される空気流量が大きく変化する場合、空気流量の脈動振幅を大きく誤検出し、誤った補正をかけることとなる。これにより、燃料噴射量や点火時期の制御精度が悪化し、内燃機関の排ガス性状や燃費が悪化するという問題がある。これを防止するため、過渡状態を判定して補正を停止するなどの処理が必要になる。 However, when the air flow rate taken into the internal combustion engine changes significantly, such as when the throttle valve is opened, the pulsation amplitude of the air flow rate is erroneously detected, resulting in erroneous correction. As a result, there is a problem that the control accuracy of the fuel injection amount and ignition timing deteriorates, and the exhaust gas properties and fuel efficiency of the internal combustion engine deteriorate. In order to prevent this, processing such as judging the transient state and stopping the correction is required.
　過渡の判定にはさまざまな方式があるが、例えば特許文献２に記載の方法では、流量平均値から加速判定しきい値を設定し、流量瞬時値がこれを越えると加速と判定する。この方式では、加速前の定常状態で脈動があると加速判定しきい値を大きく設定せざるを得ず、緩加速を適切に判定できない課題があった。 　There are various methods for judging the transition, but in the method described in Patent Document 2, for example, an acceleration judgment threshold value is set from the flow rate average value, and acceleration is judged when the flow rate instantaneous value exceeds this threshold. In this method, if there is pulsation in the steady state before acceleration, the acceleration determination threshold value must be set large, and there is a problem that slow acceleration cannot be appropriately determined.
　本発明の目的は、過渡状態の判定精度を確保し、流量センサの出力値を脈動幅に応じて適切に補正することができる内燃機関の制御装置を提供することにある。 An object of the present invention is to provide a control device for an internal combustion engine that can ensure the accuracy of determination of a transient state and can appropriately correct the output value of the flow rate sensor according to the pulsation width.
　上記目的を達成するために、本発明の内燃機関の制御装置は、流量センサの出力値の過渡状態を判定するタイミングを示す過渡状態判定用クランク角度を内燃機関の回転数ごとに少なくとも１つ設定し、前記流量センサの出力値から過渡状態判定用しきい値を少なくとも１つ設定し、前記過渡状態判定用クランク角度における前記流量センサの出力値と前記過渡状態判定用しきい値を比較して前記過渡状態であるかを判定し、前記過渡状態でない場合、前記流量センサの出力値の脈動幅に応じて前記流量センサの出力値を補正し、前記過渡状態である場合、前記流量センサの出力値の補正を制限するプロセッサを備える。 In order to achieve the above object, the control device for an internal combustion engine of the present invention sets at least one crank angle for determining a transient state indicating the timing for determining a transient state of the output value of the flow rate sensor for each rotation speed of the internal combustion engine. Then, at least one threshold value for determining a transient state is set from the output value of the flow rate sensor, and the output value of the flow rate sensor at the crank angle for determining a transient state is compared with the threshold value for determining a transient state. It is determined whether the state is the transient state, and if the state is not the transient state, the output value of the flow rate sensor is corrected according to the pulsation width of the output value of the flow rate sensor, and if the state is the transient state, the output of the flow rate sensor. A processor is provided for limiting correction of values.
　本発明によれば、過渡状態の判定精度を確保し、流量センサの出力値を脈動幅に応じて適切に補正することができる。上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。 　According to the present invention, it is possible to ensure the accuracy of determination of a transient state and appropriately correct the output value of the flow sensor according to the pulsation width. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.
本発明の実施の形態によるエンジン制御装置のシステム全体の概略構成図である。1 is a schematic configuration diagram of an entire system of an engine control device according to an embodiment of the present invention; FIG. 内燃機関の回転速度と充填効率とで規定される運転領域において、ＥＧＲを導入する運転領域を説明する図である。FIG. 2 is a diagram for explaining an operating region in which EGR is introduced in an operating region defined by the rotational speed and charging efficiency of an internal combustion engine; 内燃機関の回転速度と充填効率とで規定される運転領域において、ミラーサイクルを実施する運転領域を説明する図である。FIG. 2 is a diagram for explaining an operating region in which a Miller cycle is performed in an operating region defined by the rotational speed and charging efficiency of an internal combustion engine; 遅閉じミラーサイクルを実現する吸排気バルブリフトパターンを説明する図である。FIG. 5 is a diagram for explaining an intake/exhaust valve lift pattern that realizes a late-closing mirror cycle; 早閉じミラーサイクルを実現する吸排気バルブリフトパターンを説明する図である。FIG. 4 is a diagram for explaining an intake/exhaust valve lift pattern that realizes an early closing mirror cycle; 流量センサ部の吸気脈動挙動を説明する図である。It is a figure explaining the intake pulsation behavior of a flow sensor part. 流量センサ内部の流れの概念図を説明する図である。It is a figure explaining the conceptual diagram of the flow inside a flow sensor. 異なる脈動流れにおけるバイパス流路と主流路の各平均流速の関係を説明する図である。FIG. 4 is a diagram for explaining the relationship between average flow velocities in a bypass channel and a main channel in different pulsating flows; 脈動現象に起因して生じる流量センサ検出誤差を補正する脈動補正マップを説明する図である。FIG. 4 is a diagram for explaining a pulsation correction map for correcting a flow rate sensor detection error caused by a pulsation phenomenon; 流量センサ検出値、平均値、平均値を基に設定した加速判定しきい値を示す図である。It is a figure which shows the acceleration determination threshold value set based on the flow sensor detected value, an average value, and an average value. 脈動振幅を示す図である。It is a figure which shows a pulsation amplitude. 脈動振幅比誤検出を説明する図である。It is a figure explaining pulsation-amplitude-ratio erroneous detection. 加速判定原理を説明する図である。It is a figure explaining an acceleration determination principle. 加速判定の詳細を説明する図である。It is a figure explaining the detail of acceleration determination. ＥＣＵに実装される過渡判定および流量センサの脈動補正ロジックを説明するブロック図である。It is a block diagram explaining transient determination and the pulsation correction logic of a flow sensor mounted in ECU. 流量センサの脈動補正のフローチャートを説明する図である。It is a figure explaining the flowchart of the pulsation correction|amendment of a flow sensor. 過渡判定のフローチャートを説明する図である。It is a figure explaining the flowchart of transient determination. 加減速判定のフローチャートを説明する図である。It is a figure explaining the flowchart of acceleration/deceleration determination. 本発明の実施形態の効果を説明する図である。It is a figure explaining the effect of embodiment of this invention.
　図面を参照しながら、本発明の実施形態による内燃機関の制御装置について説明する。 A control device for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings.
　図１は、エンジン制御装置のシステム全体の概略構成図である。エンジン制御装置は、内燃機関１、流量センサ２（エアフローセンサ）、ターボ過給機３、エアバイパス弁４、インタークーラ５、過給温度センサ６（温度センサ）、スロットル弁７、吸気マニホールド８、過給圧センサ９（圧力センサ）、流動強化弁１０、吸気バルブ１１、排気バルブ１３、燃料噴射弁１５、点火プラグ１６、ノックセンサ１７、クランク角度センサ１８、ウェイストゲート弁１９、空燃比センサ２０、排気浄化触媒２１、ＥＧＲ（Exhausted Gas Recirculation）管２２、ＥＧＲクーラ２３、ＥＧＲ弁２４、温度センサ２５、差圧センサ２６およびＥＣＵ（Electronic Control Unit）２７を備えている。 FIG. 1 is a schematic configuration diagram of the entire system of the engine control device. The engine control device includes an internal combustion engine 1, a flow rate sensor 2 (airflow sensor), a turbocharger 3, an air bypass valve 4, an intercooler 5, a supercharging temperature sensor 6 (temperature sensor), a throttle valve 7, an intake manifold 8, Boost pressure sensor 9 (pressure sensor), flow enhancement valve 10, intake valve 11, exhaust valve 13, fuel injection valve 15, spark plug 16, knock sensor 17, crank angle sensor 18, waste gate valve 19, air-fuel ratio sensor 20 , an exhaust purification catalyst 21 , an EGR (Exhausted Gas Recirculation) pipe 22 , an EGR cooler 23 , an EGR valve 24 , a temperature sensor 25 , a differential pressure sensor 26 and an ECU (Electronic Control Unit) 27 .
　内燃機関１には吸気流路および排気流路が連通している。吸気流路にはエアフローセンサおよびエアフローセンサに内蔵された吸気温度センサが組み付けられている。ターボ過給機３は、コンプレッサ３ａとタービン３ｂとによって構成され、コンプレッサ３ａが吸気流路に接続され、タービン３ｂが排気流路に接続されている。 An intake flow path and an exhaust flow path communicate with the internal combustion engine 1 . An airflow sensor and an intake air temperature sensor incorporated in the airflow sensor are assembled in the intake passage. The turbocharger 3 includes a compressor 3a and a turbine 3b. The compressor 3a is connected to an intake passage, and the turbine 3b is connected to an exhaust passage.
　ターボ過給機３のタービン３ｂは、内燃機関１からの排気ガスの有するエネルギをタービン翼の回転エネルギに変換する。ターボ過給機３のコンプレッサ３ａは、タービン翼と連結されたコンプレッサ翼の回転によって、吸入流路から流入した吸入空気を圧縮する。 The turbine 3b of the turbocharger 3 converts the energy of the exhaust gas from the internal combustion engine 1 into rotational energy of turbine blades. The compressor 3a of the turbocharger 3 compresses the intake air that has flowed in from the intake passage by rotating the compressor blades connected to the turbine blades.
　インタークーラ５は、ターボ過給機３のコンプレッサ３ａの下流に設けられ、コンプレッサ３ａにより断熱圧縮されて上昇した吸入空気の吸気温度を冷却する。過給温度センサ６は、インタークーラ５の下流に組み付けられ、インタークーラ５によって冷却された吸入空気の温度（過給温度）を計測する。 The intercooler 5 is provided downstream of the compressor 3a of the turbocharger 3, and cools the temperature of the intake air that has been adiabatically compressed by the compressor 3a. The supercharging temperature sensor 6 is installed downstream of the intercooler 5 and measures the temperature of the intake air cooled by the intercooler 5 (supercharging temperature).
　スロットル弁７は、過給温度センサ６の下流に設けられ、吸入流路を絞り、内燃機関１のシリンダに流入する吸入空気量を制御する。スロットル弁７は、ドライバによるアクセルペダル踏量とは独立して弁開度の制御が可能な電子制御式バタフライ弁により構成される。スロットル弁７の下流には、過給圧センサ９が組み付けられた吸気マニホールド８が連通している。 The throttle valve 7 is provided downstream of the supercharging temperature sensor 6, throttles the intake passage, and controls the amount of intake air flowing into the cylinder of the internal combustion engine 1. The throttle valve 7 is composed of an electronically controlled butterfly valve capable of controlling the degree of opening of the valve independently of the amount of depression of the accelerator pedal by the driver. An intake manifold 8 to which a supercharging pressure sensor 9 is assembled is in communication with the downstream side of the throttle valve 7 .
　なお、スロットル弁７の下流に設けられた吸気マニホールド８とインタークーラ５とを一体化させる構成としてもよい。この場合、コンプレッサ３ａの下流からシリンダに至るまでの容積を小さくできるので、加減速の応答性向上が可能になる。 The intake manifold 8 provided downstream of the throttle valve 7 and the intercooler 5 may be integrated. In this case, since the volume from the downstream of the compressor 3a to the cylinder can be reduced, it is possible to improve the responsiveness of acceleration and deceleration.
　流動強化弁１０は、吸気マニホールド８の下流に配置され、吸入空気に偏流を生じさせることによって、シリンダ内部の流れの乱れを強化させる。内燃機関１は吸気バルブ１１および排気バルブ１３を備えている。吸気バルブ１１および排気バルブ１３は、バルブ開閉の位相を連続的に可変とするための可変動弁機構をそれぞれ有している。 The flow enhancement valve 10 is arranged downstream of the intake manifold 8 and enhances the turbulence of the flow inside the cylinder by creating a drift in the intake air. The internal combustion engine 1 has an intake valve 11 and an exhaust valve 13 . The intake valve 11 and the exhaust valve 13 each have a variable valve mechanism for continuously varying the valve opening/closing phase.
　吸気バルブ１１および排気バルブ１３の可変動弁機構には、バルブの開閉位相を検知するためのセンサ（吸気可変バルブ位置センサ１２および排気可変バルブ位置センサ１４）がそれぞれ組み付けられている。内燃機関１のシリンダには、シリンダ内に直接燃料を噴射する直接式の燃料噴射弁１５が備えられている。なお、燃料噴射弁１５は、吸気ポート内に燃料を噴射するポート噴射方式であってもよい。 Sensors (intake variable valve position sensor 12 and exhaust variable valve position sensor 14) for detecting the opening and closing phases of the valves are assembled to the variable valve mechanisms of the intake valve 11 and the exhaust valve 13, respectively. A cylinder of the internal combustion engine 1 is provided with a direct fuel injection valve 15 that injects fuel directly into the cylinder. The fuel injection valve 15 may be of a port injection type that injects fuel into the intake port.
　内燃機関１のシリンダには、シリンダ内に電極部を露出させ、スパークによって可燃混合気を引火する点火プラグ１６が組み付けられている。ノックセンサ１７は、シリンダブロックに設けられ、燃焼室内で発生するノックの有無を検出する。クランク角度センサ１８は、クランク軸の回転角度に応じた信号をクランク軸の回転速度を示す信号として後述するＥＣＵ２７へ燃焼周期ごとに出力する。 A spark plug 16 is assembled to the cylinder of the internal combustion engine 1, with an electrode portion exposed inside the cylinder and igniting a combustible air-fuel mixture by a spark. The knock sensor 17 is provided in the cylinder block and detects the presence or absence of knock occurring within the combustion chamber. The crank angle sensor 18 outputs a signal corresponding to the rotation angle of the crankshaft as a signal indicating the rotation speed of the crankshaft to the ECU 27, which will be described later, in each combustion cycle.
　空燃比センサ２０は、ターボ過給機３のタービン３ｂの下流に設けられ、検出された酸素濃度すなわち空燃比を示す信号をＥＣＵ２７へ出力する。排気浄化触媒２１は、空燃比センサ２０の下流に備えられ、排ガス中の一酸化炭素、窒素化合物および未燃炭化水素等の有害排出ガス成分を触媒反応によって浄化する。 The air-fuel ratio sensor 20 is provided downstream of the turbine 3b of the turbocharger 3, and outputs a signal indicating the detected oxygen concentration, ie, the air-fuel ratio, to the ECU 27. The exhaust purification catalyst 21 is provided downstream of the air-fuel ratio sensor 20, and purifies harmful exhaust gas components such as carbon monoxide, nitrogen compounds, and unburned hydrocarbons in the exhaust gas by catalytic reaction.
　ターボ過給機３には、エアバイパス弁４およびウェイストゲート弁１９が備えられている。エアバイパス弁４は、コンプレッサ３ａの下流からスロットル弁７の上流部までの圧力が過剰に上昇することを防ぐために、コンプレッサ３ａの上流と下流とを結ぶバイパス流路上に配置される。 The turbocharger 3 is equipped with an air bypass valve 4 and a wastegate valve 19 . The air bypass valve 4 is arranged on a bypass flow path connecting upstream and downstream of the compressor 3a in order to prevent the pressure from downstream of the compressor 3a to upstream of the throttle valve 7 from excessively increasing.
　過給状態でスロットル弁７が急激に閉止された場合には、ＥＣＵ２７の制御に従ってエアバイパス弁４が開かれることにより、コンプレッサ３ａの下流部の圧縮された吸入空気がバイパス流路を通ってコンプレッサ３ａの上流部に逆流される。その結果、過給圧を低下させることが可能となる。 When the throttle valve 7 is abruptly closed in a supercharging state, the air bypass valve 4 is opened under the control of the ECU 27, so that the compressed intake air in the downstream portion of the compressor 3a passes through the bypass passage to the compressor. It flows back to the upstream part of 3a. As a result, it becomes possible to lower the supercharging pressure.
　ウェイストゲート弁１９は、タービン３ｂの上流と下流とを結ぶバイパス流路上に配置される。ウェイストゲート弁１９は、ＥＣＵ２７の制御によって、過給圧に対して自由に弁開度が制御可能な電動式の弁である。過給圧センサ９により検知された過給圧に基づいてＥＣＵ２７によってウェイストゲート弁１９の開度が調整されると、排ガスの一部がバイパス流路を通過することにより、排ガスがタービン３ｂに与える仕事を減じることができる。その結果、過給圧を目標圧に保持することができる。 The wastegate valve 19 is arranged on a bypass flow path that connects upstream and downstream of the turbine 3b. The wastegate valve 19 is an electrically operated valve whose valve opening degree can be freely controlled with respect to the supercharging pressure under the control of the ECU 27 . When the opening degree of the waste gate valve 19 is adjusted by the ECU 27 based on the supercharging pressure detected by the supercharging pressure sensor 9, part of the exhaust gas passes through the bypass flow path, thereby supplying the exhaust gas to the turbine 3b. work can be reduced. As a result, the boost pressure can be maintained at the target pressure.
　ＥＧＲ管２２は、排気浄化触媒２１の下流部の排気流路と、コンプレッサ３ａの上流部の吸気流路とを連通し、排気浄化触媒２１の下流から排ガスを分流して、コンプレッサ３ａの上流部へ還流する。ＥＧＲ管２２に備えられたＥＧＲクーラ２３は、排ガスを冷却する。ＥＧＲ弁２４は、ＥＧＲクーラ２３の下流に備えられ、排ガスの流量を制御する。ＥＧＲ管２２には、ＥＧＲ弁２４の上流部の排ガスの温度を検出する温度センサ２５と、ＥＧＲ弁２４の上流と下流との差圧を検出する差圧センサ２６とが設けられている。 The EGR pipe 22 communicates with an exhaust passage downstream of the exhaust purification catalyst 21 and an intake passage upstream of the compressor 3a, and divides the exhaust gas from the downstream of the exhaust purification catalyst 21 to the upstream of the compressor 3a. Reflux to An EGR cooler 23 provided in the EGR pipe 22 cools the exhaust gas. The EGR valve 24 is provided downstream of the EGR cooler 23 and controls the flow rate of exhaust gas. The EGR pipe 22 is provided with a temperature sensor 25 that detects the temperature of the exhaust gas upstream of the EGR valve 24 and a differential pressure sensor 26 that detects the differential pressure between upstream and downstream of the EGR valve 24 .
　ＥＣＵ２７は、ＣＰＵ（Central Processing Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）等を有し、エンジン制御装置の各構成要素を制御したり、各種のデータ処理を実行したりする演算回路である。ＥＣＵ２７には上述した各種のセンサと各種のアクチュエータとが接続されている。 The ECU 27 has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls each component of the engine control device and executes various data processing. circuit. Various sensors and various actuators described above are connected to the ECU 27 .
　ＥＣＵ２７は、スロットル弁７、燃料噴射弁１５、可変動弁機構付き吸排気バルブ（吸気バルブ１１および排気バルブ１３）、ＥＧＲ弁２４等のアクチュエータの動作を制御する。また、ＥＣＵ２７は、各種センサから入力された信号に基づいて、内燃機関１の運転状態を検知して、運転状態に応じて決定したタイミングで点火プラグ１６に点火させる。 The ECU 27 controls the operations of actuators such as the throttle valve 7, fuel injection valve 15, intake and exhaust valves with variable valve mechanism (intake valve 11 and exhaust valve 13), EGR valve 24, and the like. The ECU 27 also detects the operating state of the internal combustion engine 1 based on signals input from various sensors, and ignites the spark plug 16 at a timing determined according to the operating state.
　以下、内燃機関１に備えられたＥＧＲシステム、ミラーサイクルシステムおよびウェイストゲートシステムによって低燃費運転を実現する内燃機関の制御方法について説明する。 A control method for the internal combustion engine that realizes fuel-efficient operation by means of the EGR system, Miller cycle system, and wastegate system provided in the internal combustion engine 1 will be described below.
　図２は、内燃機関の回転速度と充填効率（一サイクルにシリンダへ吸入される空気質量のシリンダ容積相当の標準状態空気質量に対する割合）とで規定される運転領域において、ＥＧＲを導入する運転領域を説明する図である。内燃機関の運転領域は非過給域と過給域に大別される。非過給域においては、スロットル弁によって充填効率を制御し、過給域においてはスロットル弁を開き、ウェイストゲート弁によって過給圧を制御することによって充填効率を制御する。 FIG. 2 shows an operating region in which EGR is introduced in an operating region defined by the rotational speed of the internal combustion engine and the charging efficiency (the ratio of the mass of air drawn into the cylinder in one cycle to the mass of air in the standard state equivalent to the cylinder volume). It is a figure explaining. The operating range of an internal combustion engine is roughly divided into a non-supercharging range and a supercharging range. In the non-supercharging region, the charging efficiency is controlled by the throttle valve, and in the supercharging region, the charging efficiency is controlled by opening the throttle valve and controlling the supercharging pressure by the waste gate valve.
　この様に、非過給域と過給域との間で、トルクを調整する手段を切り替えることによって、内燃機関に生じるポンプ損失を低減でき、低燃費運転を実現することができる。さらに、本実施形態で示した内燃機関にはＥＧＲシステムが搭載されている。内燃機関の非過給域の比較的高負荷条件から過給域において、ＥＧＲクーラによって冷却されたＥＧＲをシリンダに還流することによって、シリンダ内に吸入されるガスを不活性ガスであるＥＧＲで希釈し、高負荷条件で生じやすいノックと呼ばれる不正燃焼を抑制することができる。ノックを抑制できるので、点火時期を適切に進角制御することが可能となり、低燃費運転を実現することができる。 In this way, by switching the means for adjusting the torque between the non-supercharging range and the supercharging range, it is possible to reduce the pump loss that occurs in the internal combustion engine and realize fuel-efficient operation. Furthermore, the internal combustion engine shown in this embodiment is equipped with an EGR system. EGR cooled by an EGR cooler is recirculated to the cylinder from a relatively high load condition in the non-supercharging region of the internal combustion engine to a supercharging region, thereby diluting the gas sucked into the cylinder with the inert gas EGR. This makes it possible to suppress improper combustion known as knock, which tends to occur under high load conditions. Since knocking can be suppressed, the ignition timing can be controlled to advance appropriately, and fuel-efficient operation can be realized.
　図３は、内燃機関の回転速度と充填効率とで規定される運転領域において、ミラーサイクルを実施する運転領域を説明する図である。内燃機関の比較的低流量の運転領域では、シリンダに吸入する空気量を減じるために、スロットル弁がより閉じ側に制御される。これによってポンプ損失が増加する傾向がある。 FIG. 3 is a diagram explaining an operating region in which the Miller cycle is performed in an operating region defined by the rotational speed and charging efficiency of the internal combustion engine. In the relatively low flow rate operating region of the internal combustion engine, the throttle valve is controlled to be more closed in order to reduce the amount of air drawn into the cylinder. This tends to increase pump losses.
　吸気バルブ閉じ時期を下死点から早い側、もしくは遅い側にずらすことによって、ピストン圧縮仕事を低減することができ、ミラーサイクルを実現できる。スロットル弁を代替して、吸気バルブ位相を制御することによって、吸入空気量を制御すれば、スロットル弁をより開き側に設定でき、ポンプ損失を低減できる。ミラーサイクルの効果とポンプ損失低減効果により、低燃費運転を実現することができる。 By shifting the intake valve closing timing to the early side or the late side from the bottom dead center, the piston compression work can be reduced and the Miller cycle can be realized. If the amount of intake air is controlled by controlling the phase of the intake valve instead of the throttle valve, the throttle valve can be set to the open side and the pump loss can be reduced. The effect of the Miller cycle and the effect of reducing pump loss make it possible to achieve fuel-efficient operation.
　図４Ａ、４Ｂはそれぞれ、遅閉じミラーサイクル、早閉じミラーサイクルを実現する吸排気バルブリフトパターンを説明する図である。吸気バルブ位相を可変化することによって、吸気バルブ閉じ時期を、下死点を基点に早い側もしくは遅い側に設定すると、シリンダに吸入される空気量が増減する。遅閉じミラーサイクルでは、一旦シリンダ内に吸入されたガスが下死点以降に吸気管に吹き戻されることでシリンダ内への吸入空気量が抑制される。 4A and 4B are diagrams for explaining the intake and exhaust valve lift patterns that realize the late closing mirror cycle and the early closing mirror cycle, respectively. If the intake valve closing timing is set to be earlier or later than the bottom dead center by varying the intake valve phase, the amount of air taken into the cylinder increases or decreases. In the late-closing Miller cycle, the amount of air taken into the cylinder is suppressed by blowing back the gas once taken into the cylinder into the intake pipe after the bottom dead center.
　一方、早閉じミラーサイクルでは、シリンダにガスが吸入されている途中に吸気バルブが閉じられることによって、シリンダ内への吸入空気量が抑制される。本実施形態のシステムでは、吸気バルブ位相可変機構を採用してミラーサイクルを実現する構成としているが、吸気バルブリフト切換え機構や、位相・リフト連続可変機構を採用してミラーサイクルを実現することも可能である。 On the other hand, in the early-closing Miller cycle, the amount of intake air into the cylinder is suppressed by closing the intake valve while gas is being sucked into the cylinder. In the system of this embodiment, the intake valve phase variable mechanism is adopted to realize the Miller cycle, but the intake valve lift switching mechanism or the phase/lift continuously variable mechanism may be adopted to realize the Miller cycle. It is possible.
　図５は、ミラーサイクルやＥＧＲを実施した際の流量センサ部の吸気脈動挙動および脈動振幅比を説明する図である。内燃機関は各シリンダの吸気行程のみ断続的に吸気がなされるために、吸気管内には脈動を生じる。特に、低回転・高負荷領域では、低周波で脈動振幅比の大きい脈動を生じる傾向があり、流量センサの検出精度を悪化させる要因となる。 FIG. 5 is a diagram for explaining the intake pulsation behavior and the pulsation amplitude ratio of the flow rate sensor section when the Miller cycle and EGR are performed. Since the internal combustion engine intermittently takes air only during the intake stroke of each cylinder, pulsation occurs in the intake pipe. In particular, in the low rotation/high load region, there is a tendency for pulsation with a large pulsation amplitude ratio to occur at low frequencies, which is a factor that deteriorates the detection accuracy of the flow rate sensor.
　平均流速に対して脈動振幅が大きくなる低回転・高負荷条件では、流速方向が逆流を示すタイミングが存在する。脈動の周期および位相は内燃機関の回転速度に同期する。すなわち、最大値あるいは最小値となるクランク角度は内燃機関の回転速度により決まる。脈動振幅比は吸気流量の一定期間内の最大値と最小値の差である脈動幅を流量平均値で割った値で定義する。 　Under low rotation and high load conditions where the pulsation amplitude is larger than the average flow velocity, there is a timing when the flow velocity direction indicates reverse flow. The period and phase of the pulsation are synchronized with the rotational speed of the internal combustion engine. That is, the crank angle at which the maximum value or the minimum value is obtained is determined by the rotation speed of the internal combustion engine. The pulsation amplitude ratio is defined as the value obtained by dividing the pulsation width, which is the difference between the maximum value and the minimum value of the inspiratory flow rate within a certain period, by the flow rate average value.
　図６は、流量センサ内部の流れの概念を説明する図である。流量センサにはバイパス流路が備えられ、バイパス流路内に流速を検知するためのセンサエレメントが設置されている。バイパス流路形状を工夫することによって、センサエレメントへのダストや水の付着を防止することができる。 FIG. 6 is a diagram explaining the concept of the flow inside the flow sensor. The flow sensor is provided with a bypass channel, and a sensor element for detecting the flow velocity is installed in the bypass channel. Adhesion of dust and water to the sensor element can be prevented by devising the shape of the bypass channel.
　流量センサはセンサエレメントの局所流れに起因した放熱量を検出することで、流量センサ搭載部の主流の流量に対応する電圧信号を出力する。図６に示す様に、主流とバイパス流とでは流れ場の形状（長さＬ、ｌ、内径Ｄ、ｄ）、形状損失係数（Ｃｐ、ｃｐ）や摩擦損失係数（Ｃｆ、ｃｆ）がそれぞれ異なるために、異なる運動量方程式に基づく流れ場となる。 By detecting the amount of heat released by the local flow of the sensor element, the flow sensor outputs a voltage signal corresponding to the main flow rate of the flow sensor mounting part. As shown in FIG. 6, the flow field shape (length L, l, inner diameter D, d), shape loss coefficients (Cp, cp), and friction loss coefficients (Cf, cf) differ between the main stream and the bypass flow. Therefore, the flow field is based on a different momentum equation.
　図７は異なる脈動流れにおける主流路の平均流速と流量センサが計測するバイパス流路の平均流速の関係を説明する図である。バイパス流路は主流路に対して内径が小さく、曲り形状を含むため圧損が大きい。また、主流路内の偏流やバイパス流路内の偏流、共振、流量センサの応答遅れなどにより、周波数や流速の絶対値、流速方向で特性が変化する。これらにより同図が示す様に、流量センサが計測するバイパス流路の流速の平均値と主流の流速の平均値にはずれが生じるため、補正手段が必要となる。 FIG. 7 is a diagram explaining the relationship between the average flow velocity in the main flow path and the average flow velocity in the bypass flow path measured by the flow sensor for different pulsating flows. The bypass flow path has a smaller inner diameter than the main flow path and has a curved shape, resulting in a large pressure loss. In addition, the characteristics change depending on the frequency, the absolute value of the flow velocity, and the flow velocity direction due to drift in the main flow path, drift in the bypass flow path, resonance, response delay of the flow sensor, and the like. As a result, as shown in the figure, a deviation occurs between the average value of the flow velocity in the bypass channel and the average value of the flow velocity in the mainstream, which are measured by the flow rate sensor. Therefore, correction means is required.
　図８は、脈動現象に起因して生じる流量センサ検出誤差を補正する脈動補正マップの例である。脈動補正マップ適合では、内燃機関の回転速度と図５で説明した脈動振幅比を軸とするマップに補正値を記録しておく。車載時には、流量センサの検出値から脈動振幅比と機関回転数から、対応する補正量（補正値）にもとづき、流量センサの検出値を補正する。 FIG. 8 is an example of a pulsation correction map that corrects the flow rate sensor detection error caused by the pulsation phenomenon. In the pulsation correction map adaptation, a correction value is recorded in a map whose axes are the rotational speed of the internal combustion engine and the pulsation amplitude ratio described with reference to FIG. When mounted on a vehicle, the detected value of the flow sensor is corrected based on the corresponding correction amount (correction value) based on the pulsation amplitude ratio and the engine speed from the detected value of the flow sensor.
　図９Ａ～９Ｃは、加速時における流量センサ検出値と脈動振幅比を説明する図である。加速時は流量が増加するため（図９Ａ）、一定期間内の流量の最大値と最小値との差で定義した脈動振幅が上昇し（図９Ｂ）、脈動振幅比も上昇する（図９Ｃ）。この場合の流速は脈動流ではないため、図８で説明した脈動補正マップを用いて補正を行うと意図しない補正となってしまう。 　Figures 9A to 9C are diagrams for explaining the flow rate sensor detection value and the pulsation amplitude ratio during acceleration. Since the flow rate increases during acceleration (Fig. 9A), the pulsation amplitude defined as the difference between the maximum and minimum values of the flow rate within a certain period rises (Fig. 9B), and the pulsation amplitude ratio also rises (Fig. 9C). . Since the flow velocity in this case is not a pulsating flow, correction using the pulsation correction map described with reference to FIG. 8 results in unintended correction.
　図９Ａのグラフには流量平均値と流量平均値を基に設定した加速判定しきい値を記載している。この図のように加速前の定常状態での脈動振幅比が大きい場合は、定常時に誤って加速と判定しないよう加速判定しきい値を大きく設定する必要があり、加速時の流量変化が緩やかな場合に加速と判定できない。 The graph in FIG. 9A shows the flow rate average value and the acceleration determination threshold value set based on the flow rate average value. As shown in this figure, when the pulsation amplitude ratio in the steady state before acceleration is large, it is necessary to set the acceleration determination threshold value large so as not to erroneously determine acceleration during steady state. Acceleration cannot be determined in this case.
　図１０は、加速時を例とした過渡検出を説明する図である。加速した場合と定常が継続した場合を重ね書きしている。矢印でしめすタイミング、すなわち定常が継続する場合に流量が最小となるタイミングで両者に差が生じており、流量瞬時値があまり増加していなくても加速と判断することが可能である。図５で説明したように流量が最大あるいは最小となるタイミングは内燃機関の回転速度により決まっているため、このタイミングも内燃機関の回転速度毎に定めることが出来る。減速時も同様の判定を行うことが出来る。 FIG. 10 is a diagram for explaining transient detection, taking acceleration as an example. The case of acceleration and the case of continuation of steady state are overwritten. There is a difference between the two at the timing indicated by the arrow, that is, the timing at which the flow rate becomes minimum when steady state continues, and it is possible to determine acceleration even if the instantaneous flow rate value does not increase much. As described with reference to FIG. 5, the timing at which the flow rate reaches its maximum or minimum is determined by the rotation speed of the internal combustion engine, so this timing can also be determined for each rotation speed of the internal combustion engine. A similar determination can be made during deceleration.
　図１１は、加速判定しきい値を決定する方法の一例を説明する図である。図１０と同様に加速した場合と定常が継続した場合を重ね書きしている。図１１の例では、加速判定に用いるしきい値は最小値を基準に加算値を加算して設定する。脈動幅を基準に設定しても良いし、内燃機関の回転速度と平均流量などによるマップにより設定しても良い。また基準とする値は最小値以外にも平均値、最大値などを選んでも良い。 FIG. 11 is a diagram explaining an example of a method for determining the acceleration determination threshold. Similar to FIG. 10, the case of acceleration and the case of continuation of steady state are overwritten. In the example of FIG. 11, the threshold value used for acceleration determination is set by adding an additional value to the minimum value. It may be set based on the pulsation width, or may be set using a map based on the rotation speed of the internal combustion engine and the average flow rate. Besides the minimum value, an average value, a maximum value, or the like may be selected as the reference value.
　図１２は、ＥＣＵに実装される流量センサの脈動補正ロジックを説明するブロック図である。ここではまず、流量センサで採用している熱線式エアフローセンサ原理について説明する。 FIG. 12 is a block diagram explaining the pulsation correction logic of the flow rate sensor mounted on the ECU. First, the principle of the hot-wire airflow sensor used in the flow sensor will be explained.
　熱線式エアフローセンサは測定対象である空気流の中に配置された発熱抵抗体を主要な構成要素とし、発熱抵抗体に流れる電流値は吸入空気量が多い時に増加し、逆に吸入空気量が少ない時には減少するようにブリッジ回路が構成されており、発熱抵抗体に流れる電流により空気量を電圧信号として取り出すものである。 A hot-wire airflow sensor has a heating resistor placed in the airflow to be measured as its main component. A bridge circuit is constructed so that the amount of air decreases when the amount is small, and the amount of air is taken out as a voltage signal from the current flowing through the heating resistor.
　Ｂ１２０１では、流量センサから出力されるアナログ電圧信号をＡ／Ｄ変換器によってデジタル信号に変換する。Ｂ１２０２では、電圧／流量変換テーブルによってデジタル電圧信号から流量信号に換算する。尚、本実施形態では、空気量に対応した電圧信号は電圧値として出力される方式を採用しているが、電圧－周波数変換回路によって変換することにより周波数信号に変換されて出力される方式もある。 In B1201, the analog voltage signal output from the flow sensor is converted into a digital signal by an A/D converter. In B1202, the digital voltage signal is converted into a flow rate signal using a voltage/flow rate conversion table. In this embodiment, the voltage signal corresponding to the air volume is output as a voltage value, but there is also a method in which the voltage signal is converted to a frequency signal by a voltage-frequency conversion circuit and output. be.
　また、図示しないが電圧－周波数変換された周波数信号として流量センサから出力される方式の場合は、周波数信号の周期をＣＰＵのポート入力で計測することによって、周期または周期から周波数に変換された値が導出され、この周期または周波数は、予めＲＯＭに記憶された空気量変換テーブルの値から検索補間演算されて検出空気量に変換される。 In addition, although not shown in the figure, in the case of a method in which the frequency signal is output from the flow rate sensor after voltage-frequency conversion, the period of the frequency signal is measured at the port input of the CPU, and the period or the value converted from the period to the frequency is derived, and this period or frequency is converted into a detected air amount by searching and interpolating the values of the air amount conversion table stored in advance in the ROM.
　Ｂ１２０２は、一般的な熱線式エアフローセンサの吸入空気量と出力信号の関係を示したものであり、吸入空気量が少ないと出力する信号の電圧は低く、吸入空気量が多いと出力する信号の電圧は高くなる非線形関係にある特性曲線である。非線形性特性とするのは、発熱抵抗体からの検出信号を空気量に変換する際に空気量Ｑは、主としてキングの式と呼ばれる次の式が採用されているためである。
　Ｉｈ・Ｒｈ＝（α＋β・√Ｑ）・（Ｔｈ－Ｔａ）
ここで、Ｉｈは発熱抵抗体の電流値、Ｒｈは発熱抵抗の抵抗値、Ｔｈは発熱抵抗の表面温度、Ｔａは空気の温度、Ｑは空気量、α、βは発熱抵抗の仕様で決まる定数である。 B1202 shows the relationship between the amount of intake air and the output signal of a general hot-wire air flow sensor. The characteristic curve has a non-linear relationship with increasing voltage. The non-linear characteristic is used because the following equation, called King's equation, is mainly used for the amount of air Q when converting the detection signal from the heating resistor into the amount of air.
Ih · Rh = (α + β · √ Q) · (Th - Ta)
Here, Ih is the current value of the heating resistor, Rh is the resistance value of the heating resistor, Th is the surface temperature of the heating resistor, Ta is the air temperature, Q is the air volume, and α and β are constants determined by the specifications of the heating resistor. is.
　一般的には、（Ｔｈ－Ｔａ）が一定となるように発熱抵抗の電流値Ｉｈを制御するので、空気量は抵抗器の電圧降下により電圧値Ｖに変換して検出するが、結果として電圧値Ｖは４次関数式になる。このため、空気量へ変換する場合に４次曲線の曲率すなわち出力と空気量との関係が非線形になる。 In general, the current value Ih of the heating resistor is controlled so that (Th−Ta) is constant, so the amount of air is detected by converting it into a voltage value V due to the voltage drop across the resistor. The value V becomes a quartic function expression. Therefore, the curvature of the quartic curve, that is, the relationship between the output and the air amount becomes non-linear when converting to the air amount.
　Ｂ１２０３ではクランク角度センサ信号にもとづき内燃機関の回転速度を演算する。Ｂ１２０４で回転速度から最大・最小・平均値など特徴量を検出する期間を決定する。特徴量を検出する期間は回転速度とシリンダ数により決定するが、所定クランク角度毎としてもよい。 At B1203, the rotational speed of the internal combustion engine is calculated based on the crank angle sensor signal. In B1204, a period for detecting feature amounts such as maximum/minimum/average values from the rotation speed is determined. The period for detecting the feature amount is determined by the rotation speed and the number of cylinders, but it may be set for each predetermined crank angle.
　Ｂ１２０５では、加減速を判定するタイミングを設定する。回転速度毎に流量が最小となるクランク角度を加速判定タイミング、流量が最大になるクランク角度を減速判定タイミングとする。Ｂ１２０６では、特徴量検出期間内の最大値・最小値・平均値を演算する。 In B1205, the timing for judging acceleration/deceleration is set. The crank angle at which the flow rate is minimized for each rotational speed is set as the acceleration determination timing, and the crank angle at which the flow rate is maximized is set as the deceleration determination timing. In B1206, the maximum value, minimum value, and average value within the feature amount detection period are calculated.
　Ｂ１２０７では、検出された最大値・最小値を基に加減速判定用のしきい値を演算する。加速用のしきい値は最小値を基準に最大値から最小値を減算した値である脈動幅の一定割合を加算した値とし、減速用のしきい値は最大値を基準に脈動幅の一定割合を減算した値とする。なお、脈動幅が小さい場合にわずかな流量変化を加減速と誤判定しないよう加算あるいは減算する値には下限値を設けておく。 At B1207, a threshold for acceleration/deceleration determination is calculated based on the detected maximum and minimum values. The threshold for acceleration is the value obtained by subtracting the minimum value from the maximum value with the minimum value as the reference, and a fixed ratio of the pulsation width is added.The threshold for deceleration is the constant pulsation width with the maximum value as the reference. The value obtained by subtracting the ratio. A lower limit value is provided for the value to be added or subtracted so as not to misjudge a slight change in flow rate as acceleration/deceleration when the pulsation width is small.
　Ｂ１２０８では、加減速判定タイミングにおいてしきい値と流量を比較して加減速状態か定常状態かを判定する。Ｂ１２０９では検出された最大・最小・平均値より脈動振幅比を演算する。Ｂ１２１０では、定常時・過渡時それぞれの補正量を導出する。定常時は図８で説明したように脈動振幅比と回転速度により補正量を演算する。過渡時は補正を停止するような値、例えば１．０とする。 At B1208, the threshold value and the flow rate are compared at the acceleration/deceleration determination timing to determine whether the acceleration/deceleration state or the steady state. In B1209, the pulsation amplitude ratio is calculated from the detected maximum/minimum/average values. B1210 derives the correction amount for each of the steady state and the transient state. In the steady state, the correction amount is calculated from the pulsation amplitude ratio and the rotational speed as described with reference to FIG. It is set to a value such as 1.0, for example, to stop the correction during transition.
　Ｂ１２１１では、脈動振幅比補正前空気量と脈動補正量にもとづき空気流量が補正される。この様に、脈動誤差を補正する機能を定常時に限定し、過渡時に補正量を切り替えることで、脈動により流量センサ誤差を生じやすい運転条件においても、常に流量センサの精度を確保し、また、過渡時に不必要な補正を行わないことで、空燃比制御精度が向上するので、排気の悪化を防止することができる。 In B1211, the air flow rate is corrected based on the pulsation amplitude ratio pre-correction air amount and the pulsation correction amount. In this way, by limiting the function to correct the pulsation error to normal operation and switching the correction amount during transient operation, the accuracy of the flow sensor is always ensured even under operating conditions that tend to cause flow sensor error due to pulsation. Since the accuracy of air-fuel ratio control is improved by not performing unnecessary correction, deterioration of exhaust gas can be prevented.
　図１３は、流量センサの脈動補正のフローチャートを説明する図である。図で示す処理は一定クランク角度毎例えば６ｄｅｇ毎に実行される。Ｓ１３０１において流量センサ出力値をＡ／Ｄ変換する。Ｓ１３０２においてＡ／Ｄ変換された電圧値を流量に変換する。Ｓ１３０３において脈動振幅比算出用の最大値および最小値を更新する。 FIG. 13 is a diagram explaining a flow chart of pulsation correction of the flow rate sensor. The processing shown in the figure is executed at every constant crank angle, for example, every 6 degrees. In S1301, the flow sensor output value is A/D converted. In S1302, the A/D converted voltage value is converted into a flow rate. In S1303, the maximum and minimum values for calculating the pulsation amplitude ratio are updated.
　Ｓ１３０４において平均値算出用に流量を積算する。Ｓ１３０５において過渡判定を行う。詳細は図１４で説明する。Ｓ１３０６において所定クランク角度であるかの判定を行う。所定クランク角度は例えば各シリンダの圧縮上死点などである。所定クランク角度であると判定されれば、Ｓ１３０７～Ｓ１３１０の処理を行う。 In S1304, the flow rate is integrated for calculating the average value. Transient judgment is performed in S1305. Details will be described with reference to FIG. In S1306, it is determined whether or not the crank angle is a predetermined value. The predetermined crank angle is, for example, the compression top dead center of each cylinder. If it is determined to be the predetermined crank angle, the processing of S1307 to S1310 is performed.
　Ｓ１３０７においてＳ１３０４で求めた流量積算値から流量平均値を算出する。Ｓ１３０８においてＳ１３０３で求めた最大・最小値およびＳ１３０７で求めた流量平均値から脈動振幅比を算出する。Ｓ１３０９において脈動振幅比および回転速度より定常時に用いる補正量を算出する。Ｓ１３１０において最大値・最小値・流量積算値を初期化し、次回演算に備える。 At S1307, the flow rate average value is calculated from the flow rate integrated value obtained at S1304. In S1308, the pulsation amplitude ratio is calculated from the maximum/minimum value obtained in S1303 and the flow average value obtained in S1307. In S1309, a correction amount to be used in a steady state is calculated from the pulsation amplitude ratio and the rotation speed. In S1310, the maximum value, minimum value, and integrated flow rate value are initialized to prepare for the next calculation.
　Ｓ１３１１において過渡状態かどうかを判定し、過渡状態であればＳ１３１２において補正値を１．０とし、定常状態であればＳ１３１３において補正値をＳ１３０９で導出した定常時補正量とする。Ｓ１３１４において流量に補正を施して最終出力とする。 In S1311, it is determined whether or not the state is in a transient state. If the state is in a transient state, the correction value is set to 1.0 in S1312. In S1314, the flow rate is corrected to be the final output.
　図１４は、過渡判定のフローチャートを説明する図である。本処理は図１３のＳ１３０５の処理内容である。Ｓ１４０１において加減速の判定を行う。詳細は図１５で説明する。Ｓ１４０２においてＳ１４０１で加速あるいは減速の判定が成立したかの判定を行い、加速あるいは減速判定が成立した場合、Ｓ１４０３～Ｓ１４０４の処理を行い、加速あるいは減速判定が成立しない場合、Ｓ１４０５～Ｓ１４０７の処理を行う。 FIG. 14 is a diagram explaining a flow chart of transient determination. This processing is the processing content of S1305 in FIG. Acceleration/deceleration is determined in S1401. Details will be described with reference to FIG. In S1402, it is determined whether or not the determination of acceleration or deceleration is established in S1401. If the determination of acceleration or deceleration is established, the processing of S1403 to S1404 is performed. conduct.
　Ｓ１４０３において過渡状態を成立に設定し（過渡状態を示すフラグをオン）、Ｓ１４０４において定常カウンタを０に初期化する。Ｓ１４０５において定常カウンタに１を加算する。Ｓ１４０６において定常カウンタが所定値以上となったかを判定し、所定値以上の場合Ｓ１４０７で過渡状態を不成立に設定する（過渡状態を示すフラグをオフ）。 In S1403, the transient state is set to be established (the flag indicating the transient state is turned on), and the steady counter is initialized to 0 in S1404. In S1405, 1 is added to the steady counter. In S1406, it is determined whether or not the steady counter has exceeded a predetermined value, and if it is equal to or greater than the predetermined value, the transient state is set to not established (the flag indicating the transient state is turned off) in S1407.
　図１５は、加減速判定のフローチャートを説明する図である。本処理は図１４のＳ１４０１の処理内容である。Ｓ１５０１において加速判定用の最大・最小値を更新する。Ｓ１５０２において減速判定用の最大・最小値を更新する。Ｓ１５０３において加減速の判定を行うクランク角度を設定する。 FIG. 15 is a diagram for explaining a flowchart of acceleration/deceleration determination. This processing is the processing content of S1401 in FIG. In S1501, the maximum and minimum values for acceleration determination are updated. In S1502, the maximum and minimum values for deceleration determination are updated. In S1503, the crank angle for determining acceleration/deceleration is set.
　Ｓ１５０４において加速判定用のクランク角度であるかを判定し、加速判定用クランク角度であれば、Ｓ１５０５～Ｓ１５０９の処理を行う。Ｓ１５０５において、加速判定しきい値の算出を行う。加速判定しきい値は図１１で説明したように加速判定用最小値を基準に加算値を加算するが加算値は脈動幅に係数をかけたものとする。 In S1504, it is determined whether the crank angle is for acceleration determination, and if it is the acceleration determination crank angle, the processing of S1505 to S1509 is performed. At S1505, an acceleration determination threshold value is calculated. The acceleration determination threshold is obtained by adding an additional value based on the minimum value for acceleration determination as described with reference to FIG. 11, and the additional value is obtained by multiplying the pulsation width by a coefficient.
　係数は回転速度など運転状態毎に設定する。また脈動幅が小さい場合に加算値が小さくなり誤判定を引き起こすことが考えられるため、加算値には下限値を設ける。下限値は例えば最小値に係数をかけた値とする。この係数も運転状態毎に設定する。例えば、吸気脈動が無く、最大値＝最小値＝平均値であるときにこの係数を１．０とすると加算値＝平均値となり、しきい値が平均値の２倍の値となり、流量が多少変動しても誤判定を引き起こす恐れはなくなる。Ｓ１５０９において次回判定用に最大値・最小値を初期化する。 The coefficient is set for each operating state such as rotation speed. In addition, when the pulsation width is small, the additional value becomes small, which may cause an erroneous determination. Therefore, a lower limit value is set for the additional value. The lower limit value is, for example, a value obtained by multiplying the minimum value by a coefficient. This coefficient is also set for each operating state. For example, when there is no inspiratory pulsation and maximum value = minimum value = average value, if this coefficient is set to 1.0, the added value = average value, the threshold becomes twice the average value, and the flow rate decreases slightly. There is no fear of causing an erroneous determination even if the value fluctuates. In S1509, the maximum and minimum values are initialized for the next determination.
　Ｓ１５１０において減速判定用のクランク角度であるかを判定し、減速判定用クランク角度であれば、Ｓ１５１１～Ｓ１５１５の処理を行う。Ｓ１５１１において、減速判定しきい値の算出を行う。減速判定しきい値は減速判定用最大値を基準に減算値を減算するが減算値は脈動幅に係数をかけたものとする。 In S1510, it is determined whether the crank angle is for deceleration determination, and if it is the deceleration determination crank angle, the processing of S1511 to S1515 is performed. At S1511, a deceleration determination threshold value is calculated. The deceleration determination threshold value is obtained by subtracting a subtraction value based on the maximum value for deceleration determination, and the subtraction value is obtained by multiplying the pulsation width by a coefficient.
　係数は回転速度など運転状態毎に設定する。また脈動幅が小さい場合に減算値が小さくなり誤判定を引き起こすことが考えられるため、減算値には下限値を設ける。下限値は例えば最大値に係数をかけた値とする。この係数も運転状態毎に設定する。Ｓ１５１５において次回判定用に最大値・最小値を初期化する。 The coefficient is set for each operating state such as rotation speed. Also, when the pulsation width is small, the subtraction value becomes small, which may cause an erroneous determination. Therefore, a lower limit value is set for the subtraction value. The lower limit value is, for example, a value obtained by multiplying the maximum value by a coefficient. This coefficient is also set for each operating state. In S1515, the maximum and minimum values are initialized for the next determination.
　図１６は本発明の実施形態の効果を示す図である。図１６の上段は図９Ａで説明した流量センサ検出値、平均値、平均値を基に設定した加速判定しきい値に本実施形態による加速判定しきい値を重ね書きしたものである。本実施形態では加速判定を決まったクランク角度毎に実施するため、しきい値を線では無く丸で示している。 FIG. 16 is a diagram showing the effects of the embodiment of the present invention. The upper part of FIG. 16 shows the flow rate sensor detection value, the average value, and the acceleration determination threshold value set based on the average value described in FIG. 9A overlaid with the acceleration determination threshold value according to the present embodiment. In this embodiment, the acceleration determination is performed for each determined crank angle, so the threshold is indicated by a circle instead of a line.
　この図ではしきい値は最小値を基準に直近の最大値・最小値の差の９０％を加算して設定した。図で示すように定常時は加速判定タイミングにおいて誤判定を引き起こさない十分な余裕があり、加速時には速やかに加速判定ができるしきい値を設定することが出来る。 In this figure, the threshold is set by adding 90% of the difference between the latest maximum and minimum values based on the minimum value. As shown in the figure, there is sufficient leeway to prevent an erroneous determination at the timing of acceleration determination in the steady state, and a threshold value can be set that enables prompt acceleration determination in acceleration.
　なお、本実施形態では加減速しきい値を最大値あるいは最小値を基準に設定する構成としたが、これに限定されることはなく、例えば平均値を基準としても良いし、特定クランク角度での流量を基準としても良い。また、過渡時は補正を停止する構成としたが、補正値を制限するなどしても良い。 In this embodiment, the acceleration/deceleration threshold value is set based on the maximum value or the minimum value. However, the present invention is not limited to this. may be used as a reference. Also, although the configuration is such that the correction is stopped during a transition, the correction value may be limited.
　上記実施形態の主な特徴は、次のようにまとめることもできる。 The main features of the above embodiment can also be summarized as follows.
　内燃機関（エンジン）の制御装置（ＥＣＵ２７、図１）のプロセッサ（ＣＰＵ）は、流量センサ２の出力値の過渡状態を判定するタイミングを示す過渡状態判定用クランク角度を内燃機関の回転数ごとに少なくとも１つ設定する（Ｂ１２０５、図１２）。プロセッサ（ＣＰＵ）は、流量センサ２の出力値から過渡状態判定用しきい値を少なくとも１つ設定する（Ｂ１２０７、図１２）。プロセッサ（ＣＰＵ）は、過渡状態判定用クランク角度における流量センサ２の出力値と過渡状態判定用しきい値を比較して過渡状態であるかを判定する（Ｂ１２０８、図１２）。プロセッサ（ＣＰＵ）は、過渡状態でない場合（すなわち、定常状態）、流量センサ２の出力値の脈動幅に応じて流量センサ２の出力値を補正し、過渡状態である場合、流量センサの出力値の補正を制限する（Ｂ１２１０、Ｂ１２１１、図１２）。これにより、過渡状態の判定精度を確保し、流量センサの出力値を脈動幅に応じて適切に補正することができる。その結果、空燃比制御の精度が向上する。 A processor (CPU) of a control device (ECU 27, FIG. 1) for an internal combustion engine (engine) sets a transient state determination crank angle indicating the timing for determining a transient state of the output value of the flow rate sensor 2 for each rotation speed of the internal combustion engine. At least one is set (B1205, FIG. 12). The processor (CPU) sets at least one transient state determination threshold value from the output value of the flow rate sensor 2 (B1207, FIG. 12). The processor (CPU) compares the output value of the flow rate sensor 2 at the transient state determination crank angle with the transient state determination threshold to determine whether or not there is a transient state (B1208, FIG. 12). The processor (CPU) corrects the output value of the flow sensor 2 according to the pulsation width of the output value of the flow sensor 2 when it is not in a transient state (that is, in a steady state), and when it is in a transient state, the output value of the flow sensor (B1210, B1211, FIG. 12). As a result, it is possible to secure the determination accuracy of the transient state and appropriately correct the output value of the flow sensor according to the pulsation width. As a result, the accuracy of air-fuel ratio control is improved.
　なお、本実施形態では、定常状態において流量センサ２の出力値に補正値（図８）を乗じることで、流量センサ２の出力値を補正し、過渡状態において流量センサ２の出力値に補正値＝１．０を乗じて流量センサ２の出力値の補正を制限（キャンセル）している。 In this embodiment, the output value of the flow sensor 2 is corrected by multiplying the output value of the flow sensor 2 by the correction value (FIG. 8) in the steady state, and the output value of the flow sensor 2 is corrected by the correction value in the transient state. = 1.0 is multiplied to limit (cancel) the correction of the output value of the flow rate sensor 2 .
　プロセッサ（ＣＰＵ）は、流量センサ２の出力値の平均値、最大値及び最小値から脈動振幅比を算出し（Ｂ１２０９、図１２）、脈動振幅比と回転数の組み合わせに対応する補正値（図８）を用いて流量センサの出力値を補正する。これにより、脈動による流量センサの出力値の誤差を低減することができる。 The processor (CPU) calculates the pulsation amplitude ratio from the average value, the maximum value and the minimum value of the output value of the flow sensor 2 (B1209, FIG. 12), and the correction value corresponding to the combination of the pulsation amplitude ratio and the rotation speed (Fig. 8) is used to correct the output value of the flow sensor. As a result, errors in the output value of the flow rate sensor due to pulsation can be reduced.
　プロセッサ（ＣＰＵ）は、過渡状態判定用クランク角度を、回転数ごとに定常状態において流量センサ２の出力値が平均値より大きい値となるクランク角度又は平均値より小さい値となるクランク角度に設定する（図５、図１０）。例えば、プロセッサ（ＣＰＵ）は、過渡状態判定用クランク角度を、回転数ごとに定常状態において流量センサ２の出力値が最大値となるクランク角度又は最小値となるクランク角度に設定する。これにより、過渡状態の誤判定を抑制することができる。 The processor (CPU) sets the transient state determination crank angle to a crank angle at which the output value of the flow rate sensor 2 is larger than the average value or smaller than the average value in the steady state for each rotation speed. (FIGS. 5 and 10). For example, the processor (CPU) sets the crank angle for transient state determination to a crank angle at which the output value of the flow rate sensor 2 is maximized or minimized in a steady state for each rotation speed. As a result, erroneous determination of a transient state can be suppressed.
　プロセッサ（ＣＰＵ）は、所定のクランク角度の範囲における流量センサ２の出力値から基準値（最小値、最大値等）を設定し、基準値に基づいて過渡状態判定用しきい値を設定する（Ｂ１２０６、Ｂ１２０７、図１２）。これにより、流量センサの出力値（検出値）に応じて、過渡状態判定用しきい値を調整することができる。 A processor (CPU) sets a reference value (minimum value, maximum value, etc.) from the output value of the flow sensor 2 in a predetermined crank angle range, and sets a transient state determination threshold based on the reference value ( B1206, B1207, FIG. 12). Thereby, the transient state determination threshold value can be adjusted according to the output value (detected value) of the flow sensor.
　ここで、所定のクランク角度の範囲は、吸気間隔に同期した期間又はその整数倍の期間に対応するクランク角度の範囲である。例えば、所定のクランク角度の範囲は、圧縮上死点（ＴＤＣ）から次の圧縮上死点までの期間である（Ｓ１３０６、図１６）。これにより、流量センサの出力値に脈動による最大値と最小値を含めることができる。 Here, the predetermined crank angle range is a crank angle range corresponding to a period synchronized with the intake interval or an integral multiple thereof. For example, the predetermined crank angle range is the period from one compression top dead center (TDC) to the next compression top dead center (S1306, FIG. 16). As a result, the output value of the flow sensor can include the maximum and minimum values due to pulsation.
　プロセッサ（ＣＰＵ）は、基準値に所定値を加算又は減算した値を過渡状態判定用しきい値に設定する（Ｂ１２０７、図１２）。なお、図１２のＢ１２０７で用いる基準値は、所定のクランク角度の範囲における流量センサ２の出力値の最大値又は最小値であるが平均値であってもよい。これにより、流量センサの出力値の分布の特性値に応じて過渡状態判定用しきい値を調整することができる。 The processor (CPU) sets a value obtained by adding or subtracting a predetermined value to or from the reference value as the transient state determination threshold value (B1207, FIG. 12). The reference value used in B1207 of FIG. 12 is the maximum or minimum output value of the flow rate sensor 2 within a predetermined crank angle range, but may be an average value. Thereby, the transient state determination threshold value can be adjusted according to the characteristic value of the distribution of the output value of the flow sensor.
　プロセッサ（ＣＰＵ）は、所定のクランク角度の範囲における流量センサ２の出力値の最大値と最小値との差に第１係数を乗じた値を算出し、算出した値を前記所定値（加算値）に設定する（Ｓ１５０５、図１５）。これにより、脈動幅に応じて過渡状態判定用しきい値を調整することができる。 The processor (CPU) calculates a value obtained by multiplying the difference between the maximum value and the minimum value of the output value of the flow rate sensor 2 in a predetermined crank angle range by a first coefficient, and converts the calculated value to the predetermined value (addition value ) (S1505, FIG. 15). As a result, the transient state determination threshold value can be adjusted according to the pulsation width.
　過渡状態は、例えば、加速要求に応じて吸気流量が過渡的に増加する状態である。プロセッサ（ＣＰＵ）は、所定のクランク角度の範囲における流量センサ２の出力値の最小値に所定値を加算した値を過渡状態判定用しきい値（加速判定しきい値）に設定する（Ｂ１２０７、図１２）。プロセッサ（ＣＰＵ）は、過渡状態判定用クランク角度における流量センサ２の出力値が過渡状態判定用しきい値より大きい場合、過渡状態であると判定する（Ｓ１５０６：ＹＥＳ、Ｓ１５０７、図１５）。これにより、加速による過渡状態の判定精度が向上する。 A transient state is, for example, a state in which the intake flow rate transiently increases in response to an acceleration request. The processor (CPU) sets a value obtained by adding a predetermined value to the minimum value of the output value of the flow rate sensor 2 in a predetermined crank angle range as a transient state determination threshold value (acceleration determination threshold value) (B1207, Figure 12). The processor (CPU) determines that there is a transient state when the output value of the flow rate sensor 2 at the transient state determination crank angle is greater than the transient state determination threshold value (S1506: YES, S1507, FIG. 15). This improves the accuracy of determination of a transient state due to acceleration.
　また、過渡状態は、例えば、減速要求に応じて吸気流量が過渡的に減少する状態である。プロセッサ（ＣＰＵ）は、所定のクランク角度の範囲における流量センサ２の出力値の最大値に所定値を減算した値を過渡状態判定用しきい値（減速判定しきい値）に設定する（Ｂ１２０７、図１２）。プロセッサ（ＣＰＵ）は、過渡状態判定用クランク角度における流量センサ２の出力値が過渡状態判定用しきい値より小さい場合、過渡状態であると判定する（Ｓ１５１２：ＹＥＳ、Ｓ１５１３、図１５）。これにより、減速による過渡状態の判定精度が向上する。 Also, the transient state is, for example, a state in which the intake flow rate transiently decreases in response to a deceleration request. The processor (CPU) sets a value obtained by subtracting a predetermined value from the maximum value of the output value of the flow rate sensor 2 in a predetermined crank angle range as a transient state determination threshold value (deceleration determination threshold value) (B1207, Figure 12). If the output value of the flow rate sensor 2 at the transient state determination crank angle is smaller than the transient state determination threshold value, the processor (CPU) determines that there is a transient state (S1512: YES, S1513, FIG. 15). This improves the accuracy of determining a transient state due to deceleration.
　プロセッサ（ＣＰＵ）は、所定のクランク角度の範囲における流量センサ２の出力値の最大値又は最小値に第２係数を乗じた値を算出し、算出した値を前記所定値（加算値、減算値）の下限値に設定する（Ｓ１５０５、Ｓ１５１１、図１５）。これにより、脈動幅が小さい場合に過渡状態の誤判定を抑制することができる。 The processor (CPU) calculates a value obtained by multiplying the maximum value or minimum value of the output value of the flow sensor 2 in a predetermined crank angle range by a second coefficient, and converts the calculated value to the predetermined value (addition value, subtraction value ) (S1505, S1511, FIG. 15). As a result, erroneous determination of a transient state can be suppressed when the pulsation width is small.
　なお、本発明は上記した実施形態に限定されるものではなく、様々な変形例が含まれる。例えば、上述した実施形態は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、また、ある実施形態の構成に他の実施形態の構成を加えることも可能である。また、各実施形態の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.
　また、上記の各構成、機能等は、それらの一部又は全部を、例えば集積回路で設計する等によりハードウェアで実現してもよい。また、上記の各構成、機能等は、プロセッサがそれぞれの機能を実現するプログラムを解釈し、実行することによりソフトウェアで実現してもよい。各機能を実現するプログラム、テーブル、ファイル等の情報は、メモリや、ハードディスク、SSD（Solid State Drive）等の記録装置、または、ICカード、SDカード、DVD等の記録媒体に置くことができる。 In addition, each of the above configurations, functions, etc. may be realized by hardware, for example, by designing a part or all of them with an integrated circuit. Moreover, each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function. Information such as programs, tables, files, etc. that realize each function can be stored in memory, hard disks, SSD (Solid State Drives) and other recording devices, or IC cards, SD cards, DVDs and other recording media.
　なお、本発明の実施形態は、以下の態様であってもよい。 It should be noted that the embodiment of the present invention may have the following aspects.
　（１）．吸気管内流れの局所流量を測定する流量センサを備えた内燃機関の制御装置であって、流量センサ出力値を補正する補正値を求める手段と、機関回転数から過渡状態判定用クランク角度を少なくとも１つ設定する手段と、前記流量センサの出力値から過渡状態判定用しきい値を少なくとも１つ設定する手段と、前記過渡状態判定用クランク角度における前記流量センサの出力値と前記過渡状態判定用しきい値を比較して過渡状態を判定する手段と、を備え、前記流量の補正値を定常、過渡の状態に応じて切り替えて前記流量センサの出力値を補正して吸入空気流量を演算する手段を備えることを特徴とする内燃機関の制御装置。 (1). A control device for an internal combustion engine having a flow sensor for measuring a local flow rate of a flow in an intake pipe, comprising: means for obtaining a correction value for correcting an output value of the flow sensor; means for setting at least one threshold value for determining a transient state based on the output value of the flow rate sensor; and an output value of the flow rate sensor at the crank angle for determining the transient state and the threshold value for determining the transient state. means for comparing the threshold value and determining a transient state, and means for calculating an intake air flow rate by switching the correction value of the flow rate according to a steady state or a transient state to correct the output value of the flow rate sensor. A control device for an internal combustion engine, comprising:
　（２）．前記流量センサ出力値を補正する補正値は、所定のクランク角度間の平均値・最大値・最小値から算出される脈動振幅比と機関回転数から算出することを特徴とする（１）に記載の内燃機関の制御装置。 (2). (1), wherein the correction value for correcting the flow rate sensor output value is calculated from the pulsation amplitude ratio calculated from the average value, maximum value, and minimum value between predetermined crank angles and the engine speed. internal combustion engine controller.
　（３）．前記過渡状態判定用クランク角度は、機関回転数毎に定常状態において流量センサの検出する流量が平均値よりも大きい値となるクランク角度、あるいは平均値よりも小さな値となるクランク角度に設定することを特徴とする（１）に記載の内燃機関の制御装置。 (3). The transient state determination crank angle is set to a crank angle at which the flow rate detected by the flow rate sensor in a steady state for each engine speed is larger than the average value or smaller than the average value. The control device for an internal combustion engine according to (1), characterized by:
　（４）．前記過渡状態判定用しきい値は、所定のクランク角度間の流量センサの出力値のいずれかあるいは複数の値から計算された値を基準に設定することを特徴とする（１）に記載の内燃機関の制御装置。 (4). The internal combustion engine according to (1), wherein the transient state determination threshold value is set based on a value calculated from one or a plurality of output values of a flow rate sensor between predetermined crank angles. Engine control device.
　（５）．前記過渡状態判定用しきい値は、所定のクランク角度間の流量センサの出力値の最大値あるいは最小値を基準に設定することを特徴とする（４）に記載の内燃機関の制御装置。 (5). The control device for an internal combustion engine according to (4), wherein the transient state determination threshold value is set based on the maximum value or minimum value of the output value of the flow rate sensor between predetermined crank angles.
　（６）．前記過渡状態判定用しきい値は、所定のクランク角度間の流量センサの出力値の平均値を基準に加算あるいは減算して設定することを特徴とする（４）に記載の内燃機関の制御装置。 (6). The control device for an internal combustion engine according to (4), wherein the threshold value for determining the transient state is set by adding or subtracting from an average value of output values of the flow rate sensor between predetermined crank angles. .
　（７）．前記過渡状態判定用しきい値は、所定のクランク角度間の流量センサの出力値の最大値と最小値との差に所定値を乗じて算出した値を基準値に加算あるいは減算して設定することを特徴とする（４）に記載の内燃機関の制御装置。 (7). The threshold value for determining the transient state is set by adding or subtracting a value calculated by multiplying the difference between the maximum value and the minimum value of the output value of the flow rate sensor between predetermined crank angles by a predetermined value to or from the reference value. The control device for an internal combustion engine according to (4), characterized in that:
　（８）．前記過渡状態判定用しきい値は、基準値との差を所定値以上に制限して設定することを特徴とする（４）に記載の内燃機関の制御装置。 (8). A control apparatus for an internal combustion engine according to (4), wherein the transient state determination threshold value is set by limiting a difference from a reference value to a predetermined value or more.
　（９）．前記所定のクランク角度間は、吸気間隔に同期した期間あるいはその整数倍の期間とすることを特徴とする（２）から（７）のいずれかに記載の内燃機関の制御装置。 (9). A control apparatus for an internal combustion engine according to any one of (2) to (7), wherein the predetermined crank angle interval is a period synchronized with an intake interval or an integral multiple thereof.
　（１）～（９）によれば、流量センサ位置において吸入空気流れの脈動を検出して補正を行うものにおいて、過渡時に懸念される脈動の誤検出による補正値のエラーによる内燃機関の排ガス性状の悪化や、燃費の悪化を防止することができる。 According to (1) to (9), in the one that detects and corrects the pulsation of the intake air flow at the flow sensor position, the exhaust gas property of the internal combustion engine due to the error in the correction value due to the erroneous detection of the pulsation that is a concern at the time of transition It is possible to prevent deterioration of fuel efficiency and deterioration of fuel efficiency.
１　内燃機関、　２　流量センサ、
３　ターボ過給機、　３ａ　コンプレッサ、
３ｂ　タービン、　４　エアバイパス弁、
５　インタークーラ、　６　過給温度センサ、
７　スロットル弁、　８　吸気マニホールド、
９　過給圧センサ、　１０　流動強化弁、
１１　吸気バルブ、　１２　吸気可変バルブ位置センサ、
１３　排気バルブ、　１４　排気可変バルブ位置センサ、
１５　燃料噴射弁、　１６　点火プラグ、
１７　ノックセンサ、　１８　クランク角度センサ、
１９　ウェイストゲート弁、　２０　空燃比センサ、
２１　排気浄化触媒、　２２　ＥＧＲ管、
２３　ＥＧＲクーラ、　２４　ＥＧＲ弁、
２５　温度センサ、　２６　差圧センサ、　２７　ＥＣＵ 1 internal combustion engine, 2 flow rate sensor,
3 turbocharger, 3a compressor,
3b turbine, 4 air bypass valve,
5 intercooler, 6 supercharging temperature sensor,
7 throttle valve, 8 intake manifold,
9 boost pressure sensor, 10 flow enhancement valve,
11 intake valve, 12 variable intake valve position sensor,
13 Exhaust valve 14 Exhaust variable valve position sensor
15 fuel injection valve, 16 spark plug,
17 knock sensor, 18 crank angle sensor,
19 wastegate valve, 20 air-fuel ratio sensor,
21 exhaust purification catalyst, 22 EGR pipe,
23 EGR cooler, 24 EGR valve,
25 temperature sensor, 26 differential pressure sensor, 27 ECU

Claims (13)

  1. 　流量センサの出力値の過渡状態を判定するタイミングを示す過渡状態判定用クランク角度を内燃機関の回転数ごとに少なくとも１つ設定し、
    　前記流量センサの出力値から過渡状態判定用しきい値を少なくとも１つ設定し、
    　前記過渡状態判定用クランク角度における前記流量センサの出力値と前記過渡状態判定用しきい値を比較して前記過渡状態であるかを判定し、
    　前記過渡状態でない場合、前記流量センサの出力値の脈動幅に応じて前記流量センサの出力値を補正し、前記過渡状態である場合、前記流量センサの出力値の補正を制限するプロセッサを備える内燃機関の制御装置。     setting at least one crank angle for determining a transient state indicating a timing for determining a transient state of the output value of the flow rate sensor for each rotation speed of the internal combustion engine;
    setting at least one threshold value for determining a transient state from the output value of the flow sensor;
    comparing the output value of the flow rate sensor at the transient state determination crank angle with the transient state determination threshold value to determine whether the transient state exists;
    a processor for correcting the output value of the flow sensor according to the pulsation width of the output value of the flow sensor when the state is not the transient state, and limiting the correction of the output value of the flow sensor when the state is the transient state; Engine control device.
  2. 　請求項１に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　前記流量センサの出力値の平均値、最大値及び最小値から脈動振幅比を算出し、前記脈動振幅比と前記回転数の組み合わせに対応する補正値を用いて前記流量センサの出力値を補正する
    　ことを特徴とする内燃機関の制御装置。     The control device for an internal combustion engine according to claim 1,
    The processor
    A pulsation amplitude ratio is calculated from the average value, the maximum value and the minimum value of the output values of the flow sensor, and the output value of the flow sensor is corrected using a correction value corresponding to the combination of the pulsation amplitude ratio and the rotation speed. A control device for an internal combustion engine, characterized by:
  3. 　請求項１に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　前記過渡状態判定用クランク角度を、回転数ごとに定常状態において前記流量センサの出力値が平均値より大きい値となるクランク角度又は平均値より小さい値となるクランク角度に設定する
    　ことを特徴とする内燃機関の制御装置。     The control device for an internal combustion engine according to claim 1,
    The processor
    The crank angle for transient state determination is set to a crank angle at which the output value of the flow rate sensor in a steady state is larger than the average value or smaller than the average value for each rotation speed. A control device for an internal combustion engine.
  4. 　請求項１に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　所定のクランク角度の範囲における前記流量センサの出力値から基準値を設定し、前記基準値に基づいて前記過渡状態判定用しきい値を設定する
    　ことを特徴とする内燃機関の制御装置。     The control device for an internal combustion engine according to claim 1,
    The processor
    A control device for an internal combustion engine, wherein a reference value is set from the output value of the flow rate sensor in a predetermined crank angle range, and the threshold value for determining the transient state is set based on the reference value.
  5. 　請求項４に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　前記基準値に所定値を加算又は減算した値を前記過渡状態判定用しきい値に設定する
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 4,
    The processor
    A control device for an internal combustion engine, wherein a value obtained by adding or subtracting a predetermined value to or from the reference value is set as the transient state determination threshold value.
  6. 　請求項５に記載の内燃機関の制御装置であって、
    　前記基準値は、前記所定のクランク角度の範囲における前記流量センサの出力値の最大値又は最小値である
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 5,
    A control device for an internal combustion engine, wherein the reference value is the maximum value or the minimum value of the output value of the flow rate sensor in the predetermined crank angle range.
  7. 　請求項５に記載の内燃機関の制御装置であって、
    　前記基準値は、前記所定のクランク角度の範囲における前記流量センサの出力値の平均値である
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 5,
    A control apparatus for an internal combustion engine, wherein the reference value is an average value of output values of the flow rate sensor in the predetermined crank angle range.
  8. 　請求項５に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　前記所定のクランク角度の範囲における前記流量センサの出力値の最大値と最小値との差に第１係数を乗じた値を算出し、算出した値を前記所定値に設定する
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 5,
    The processor
    A value is calculated by multiplying a difference between the maximum value and the minimum value of the output value of the flow rate sensor in the predetermined crank angle range by a first coefficient, and the calculated value is set as the predetermined value. A control device for an internal combustion engine.
  9. 　請求項４に記載の内燃機関の制御装置であって、
    　前記所定のクランク角度の範囲は、吸気間隔に同期した期間又はその整数倍の期間に対応するクランク角度の範囲である
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 4,
    A control apparatus for an internal combustion engine, wherein the predetermined crank angle range is a crank angle range corresponding to a period synchronized with an intake interval or an integer multiple thereof.
  10. 　請求項６に記載の内燃機関の制御装置であって、
    　前記過渡状態は、加速要求に応じて吸気流量が過渡的に増加する状態であり、
    　前記プロセッサは、
    　前記所定のクランク角度の範囲における前記流量センサの出力値の最小値に所定値を加算した値を前記過渡状態判定用しきい値に設定し、
    　前記過渡状態判定用クランク角度における前記流量センサの出力値が前記過渡状態判定用しきい値より大きい場合、前記過渡状態であると判定する
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 6,
    The transient state is a state in which the intake flow rate transiently increases in response to the acceleration request,
    The processor
    setting a value obtained by adding a predetermined value to the minimum value of the output value of the flow rate sensor in the predetermined crank angle range as the transient state determination threshold;
    A control device for an internal combustion engine, wherein when an output value of the flow rate sensor at the transient state determination crank angle is greater than the transient state determination threshold value, it is determined that the transient state exists.
  11. 　請求項６に記載の内燃機関の制御装置であって、
    　前記過渡状態は、減速要求に応じて吸気流量が過渡的に減少する状態であり、
    　前記プロセッサは、
    　前記所定のクランク角度の範囲における前記流量センサの出力値の最大値に所定値を減算した値を前記過渡状態判定用しきい値に設定し、
    　前記過渡状態判定用クランク角度における前記流量センサの出力値が前記過渡状態判定用しきい値より小さい場合、前記過渡状態であると判定する
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 6,
    The transient state is a state in which the intake flow rate transiently decreases in response to the deceleration request,
    The processor
    setting a value obtained by subtracting a predetermined value from the maximum value of the output value of the flow rate sensor in the predetermined crank angle range as the transient state determination threshold;
    A control device for an internal combustion engine, wherein when an output value of the flow rate sensor at the transient state determination crank angle is smaller than the transient state determination threshold value, it is determined that the transient state exists.
  12. 　請求項８に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　前記所定のクランク角度の範囲における前記流量センサの出力値の最大値又は最小値に第２係数を乗じた値を算出し、算出した値を前記所定値の下限値に設定する
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 8,
    The processor
    A value obtained by multiplying the maximum or minimum output value of the flow rate sensor in the predetermined crank angle range by a second coefficient is calculated, and the calculated value is set as the lower limit of the predetermined value. A control device for an internal combustion engine.
  13. 　請求項３に記載の内燃機関の制御装置であって、
    　前記プロセッサは、
    　前記過渡状態判定用クランク角度を、回転数ごとに定常状態において前記流量センサの出力値が最大値となるクランク角度又は最小値となるクランク角度に設定する
    　ことを特徴とする内燃機関の制御装置。     A control device for an internal combustion engine according to claim 3,
    The processor
    A control device for an internal combustion engine, wherein the crank angle for transient state determination is set to a crank angle at which the output value of the flow rate sensor in a steady state is maximized or minimized for each rotation speed.
PCT/JP2021/044124 2021-12-01 2021-12-01 Control device for internal combustion engine WO2023100294A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11117793A (en) * 1997-10-20 1999-04-27 Mitsubishi Electric Corp Fuel injection controller for internal combustion engine
JP2002147269A (en) * 2000-11-09 2002-05-22 Yamaha Motor Co Ltd Engine control device
JP2014020212A (en) * 2012-07-12 2014-02-03 Hitachi Automotive Systems Ltd Control device for internal combustion engine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11117793A (en) * 1997-10-20 1999-04-27 Mitsubishi Electric Corp Fuel injection controller for internal combustion engine
JP2002147269A (en) * 2000-11-09 2002-05-22 Yamaha Motor Co Ltd Engine control device
JP2014020212A (en) * 2012-07-12 2014-02-03 Hitachi Automotive Systems Ltd Control device for internal combustion engine

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