JP6490239B2 - Combustion state estimation device - Google Patents

Description

  The present invention relates to a combustion state estimation device.

  JP2013-68130A discloses one that detects the in-cylinder pressure of each cylinder by an in-cylinder pressure sensor provided for each cylinder of the internal combustion engine.

  Here, as a method of estimating the combustion state of the cylinder, a method of estimating the combustion state of the cylinder based on the detection value of the in-cylinder pressure sensor can be considered. However, in practice, it is difficult to estimate the combustion state of the cylinder based on the detection value of the in-cylinder pressure sensor, and a method for estimating the combustion state of the cylinder without using the in-cylinder pressure sensor is required.

  The present invention has been made paying attention to such problems, and an object thereof is to estimate the combustion state of a cylinder without using an in-cylinder pressure sensor.

  In order to solve the above-described problems, a combustion state estimation device according to an aspect of the present invention is rotatably accommodated in a housing provided on an exhaust path of an engine body having a cylinder, and at least one blade is provided. A rotating body that is rotationally driven by the energy of the exhaust gas discharged from each cylinder of the engine body, and a passage that is provided in the housing and detects that the blade of the rotating body has passed through a predetermined position in the housing. The angular velocity of the rotating body is calculated based on the detection sensor and the detection result of the passage detection sensor, and at least one of the combustion energy or the combustion interval of the cylinder of the engine body is calculated based on the angular velocity of the rotating body. And a configured arithmetic device.

  According to the combustion state estimation device according to this aspect of the present invention, by providing the combustion state estimation device on the exhaust path, the combustion state of the cylinder such as the combustion energy and the combustion interval of the cylinder of the engine body can be estimated. Therefore, the combustion state of the cylinder can be estimated without using the in-cylinder pressure sensor.

FIG. 1 is a schematic configuration diagram of an internal combustion engine according to an embodiment of the present invention. FIG. 2A is a schematic cross-sectional view of a rotating body and a housing. FIG. 2B is a schematic plan view of the rotating body. FIG. 3 is a diagram for explaining the detection principle of an eddy current sensor as a passage detection sensor. FIG. 4A is a diagram showing a transition of an output value when an eddy current sensor is used as a passage detection sensor. FIG. 4B is a diagram showing a transition of an output value when an eddy current sensor is used as a passage detection sensor. FIG. 5 is a diagram illustrating an example of the calculation result of the angular velocity of the compressor wheel when the rotating body is rotated at a constant angular velocity. FIG. 6 is a schematic plan view of a rotating body in which a shape error has occurred in the blade. FIG. 7 is a diagram showing transition of the angular velocity and kinetic energy of the rotating body in one cycle of the internal combustion engine. FIG. 8 is a diagram for explaining a method for calculating the combustion energy of each cylinder and the combustion interval of each cylinder. FIG. 9 is a flowchart illustrating the angular velocity calculation control of the rotating body according to the embodiment of the present invention. FIG. 10 is a flowchart illustrating the estimation control of the combustion energy of each cylinder of the engine body according to the embodiment of the present invention. FIG. 11 is a flowchart for explaining the estimation control of the combustion interval of each cylinder of the engine body according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are assigned to similar components.

<Overall configuration>
FIG. 1 is a schematic configuration diagram of an internal combustion engine 100 according to an embodiment of the present invention.

  The internal combustion engine 100 includes an engine body 1, an intake device 20, an exhaust device 30, and an electronic control unit 200 for controlling the internal combustion engine 100. The internal combustion engine 100 is a so-called multi-cylinder internal combustion engine in which the engine body 1 has a plurality of cylinders 4.

  The engine body 1 burns fuel in a combustion chamber 6 formed in each cylinder 4 to generate power for driving a vehicle, for example. In the present embodiment, the engine body 1 has four cylinders 4. However, the number of cylinders is not particularly limited, and may be one (single cylinder), for example. In this embodiment, the engine body 1 sparks and burns fuel in the combustion chamber 6, but the fuel combustion method is not particularly limited, and the fuel may be compressed and self-ignited and burned in the combustion chamber. . Hereinafter, the configuration of the engine body 1 will be described.

  The engine body 1 includes a cylinder block 2 and a cylinder head 3 fixed to the upper surface of the cylinder block 2.

  A plurality of cylinders 4 are formed in the cylinder block 2. Inside the cylinder 4 is received a piston 5 that receives combustion pressure and reciprocates inside the cylinder 4. The piston 5 is connected to a crankshaft via a connecting rod, and the reciprocating motion of the piston 5 is converted into rotational motion by the crankshaft. A space defined by the inner wall surface of the cylinder head 3, the inner wall surface of the cylinder 4, and the piston crown surface is a combustion chamber 6.

  The cylinder head 3 has an intake port 7 that opens to one side surface of the cylinder head 3 and opens to the combustion chamber 6 of each cylinder 4, and opens to the other side surface of the cylinder head 3 and combustion chamber of each cylinder 4. 6 is formed.

  The cylinder head 3 includes an intake valve 9 for opening and closing the opening between the combustion chamber 6 and the intake port 7, an exhaust valve 10 for opening and closing the opening between the combustion chamber 6 and the exhaust port 8, and an intake valve 9. An intake camshaft 11 that opens and closes and an exhaust camshaft 12 that opens and closes the exhaust valve 10 are attached.

  Further, the cylinder head 3 has a fuel injection valve 13 for injecting fuel into the combustion chamber 6, and an ignition for igniting the mixture of fuel and air injected from the fuel injection valve 13 in the combustion chamber 6. A plug 14 is attached. The fuel injection valve 13 may be attached so as to inject fuel into the intake port 7.

  The intake device 20 is a device for introducing air into the cylinder 4 through the intake port 7, and includes an air cleaner 21, an intake pipe 22, an intake manifold 23, an electronically controlled throttle valve 24, and an air flow meter. 211.

  The air cleaner 21 removes foreign matters such as sand contained in the air.

  One end of the intake pipe 22 is connected to the air cleaner 21, and the other end is connected to a surge tank 23 a of the intake manifold 23. The intake pipe 22 guides air (intake air) flowing into the intake pipe 22 via the air cleaner 21 to the surge tank 23 a of the intake manifold 23.

  The intake manifold 23 includes a surge tank 23a and a plurality of intake branch pipes 23b branched from the surge tank 23a and connected to the openings of the intake ports 7 formed on the side surface of the cylinder head. The air guided to the surge tank 23a is evenly distributed in each cylinder 4 through the intake branch pipe 23b.

  The throttle valve 24 is provided in the intake pipe 22. The throttle valve 24 is driven by a throttle actuator 25 to change the passage cross-sectional area of the intake pipe 22 continuously or stepwise. By adjusting the opening of the throttle valve 24 (hereinafter referred to as “throttle opening”) by the throttle actuator 25, the amount of intake air taken into each cylinder 4 is adjusted. The throttle opening is detected by the throttle sensor 212.

  The air flow meter 211 is provided in the intake pipe 22 on the upstream side of the throttle valve 24. The air flow meter 211 detects the flow rate of air flowing through the intake pipe 22 (hereinafter referred to as “intake amount”).

  The exhaust device 30 is a device for purifying the combustion gas (exhaust gas) generated in the combustion chamber 6 and discharging it to the outside air. The exhaust device 30 includes an exhaust manifold 31, an exhaust pipe 32, and an exhaust aftertreatment device 33. Prepare.

  The exhaust manifold 31 includes a plurality of exhaust branch pipes 31a connected to the openings of the exhaust ports 8 formed on the side surface of the cylinder head, and a collection pipe 31b that collects the exhaust branch pipes 31a into one. Prepare.

  The exhaust pipe 32 has one end connected to the collecting pipe 31b of the exhaust manifold 31 and the other end opened to the outside air. Exhaust gas discharged from each cylinder 4 through the exhaust port 8 to the exhaust manifold 31 flows through the exhaust pipe 32 and is discharged to the outside air.

  The exhaust aftertreatment device 33 is a device for purifying exhaust gas and discharging it to the outside air, and includes various catalysts for purifying harmful substances, filters for collecting harmful substances, and the like.

  The internal combustion engine 100 according to the present embodiment further includes a combustion state estimation device 40 for estimating the combustion state of each cylinder 4 such as the combustion energy of each cylinder 4 of the engine body 1 and the combustion interval of each cylinder 4. The combustion state estimation device 40 includes a housing 41 connected to the exhaust pipe 32, a rotating body 42 rotatably disposed in the housing 41, a passage detection sensor 301 attached to the housing 41, and a passage detection sensor 301. The angular velocity of the rotating body 42 is calculated based on the output result, and the combustion state of each cylinder 4 such as the combustion energy of each cylinder 4 of the engine body 1 and the combustion interval of each cylinder 4 is estimated based on the angular velocity of the rotating body 42. And an amplifier unit 300 configured to be able to do this. Details of the combustion state estimation device 40 will be described later with reference to FIG.

  The electronic control unit 200 includes a digital computer and includes a ROM (read only memory), a RAM (random access memory), a CPU (microprocessor), an input port, and an output port that are connected to each other via a bidirectional bus.

  In addition to the output signals from the air flow meter 211 and the throttle sensor 212 described above, the electronic control unit 200 provides a signal for calculating the engine speed every time the crankshaft of the engine body 1 rotates, for example, 15 °. An output signal such as a crank angle sensor 213 that generates an output pulse is input via an input port. As described above, output signals of various sensors necessary for controlling the internal combustion engine 100 are input to the electronic control unit 200 via the input port.

  The electronic control unit 200 is electrically connected with control components such as the fuel injection valve 13, the spark plug 14, and the throttle actuator 25 through output ports.

  The electronic control unit 200 is connected to the amplifier unit 300 via a CAN (Controller Area Network) communication line so that data can be transmitted and received with each other by CAN communication. In the present embodiment, the combustion state of each cylinder 4 of the engine body 1 estimated by the amplifier unit 300 is transmitted to the electronic control unit 200. Then, the electronic control unit 200 according to the present embodiment, depending on the combustion state of each cylinder 4 of the engine body 1 transmitted from the amplifier unit 300, parameters related to combustion of each cylinder 4, that is, the combustion injection amount, the intake amount, and the ignition It is configured to be able to control time etc.

<Configuration of combustion state estimation device>
FIG. 2A is a schematic cross-sectional view of the housing 41 and the rotating body 42. FIG. 2B is a schematic plan view of the rotating body 42.

  As shown in FIG. 2A, the rotating body 42 includes a central body 421 fixed to a shaft 423 rotatably supported by a rolling bearing 424, and a radial direction and an axial direction of the rotating body 42 from the surface of the central body 421. A plurality of blades 422 extending. The central body 421 is fixed to the shaft 423 so that its axis L is coaxial with the axis of the shaft 423.

  The rotating body 42 is disposed inside the housing 41 so as to be rotatable around the axis L. Further, when the rotating body 42 rotates, the radial end portion of the blade 422 moves in the circumferential direction along the inner peripheral surface with a slight gap from the inner peripheral surface of the housing 41. Arranged inside the housing 41.

  As shown in FIG. 2B, the rotating body 42 according to the present embodiment has twelve blades 422 having the same shape and arranged at equal intervals. In FIG. 2B, for ease of explanation, the blades 422 are numbered B1 to B12, respectively. The number of blades 422 is not limited to twelve, and may be more than twelve or less than twelve. In the present embodiment, each blade 422 is configured to extend in the radial direction and the axial direction of the rotating body 42. However, the plurality of blades 422 may have any shape such as a curved shape as long as the rotating body 42 can be rotationally driven by the exhaust gas flowing into the housing 41. The blades 422 are not necessarily arranged at equal intervals, and a part or all of the blades 422 may have a different shape from the other blades.

  Returning to FIG. 2A, the housing 41 has a central passage 411 extending through the center of the housing 41 and an annular passage 412 extending around the central passage 411 and into which exhaust gas flowing through the exhaust pipe flows. An annular passage 412 is disposed around one end (left side in the figure) of the central passage 411, and the rotating body 42 is disposed in the central passage 411 inside the annular passage 412. The other end (right side in the figure) of the central passage 411 is open, and constitutes an outlet 413 through which exhaust flows out. Therefore, the exhaust gas flowing through the exhaust pipe 32 flows out from the outlet 413 of the central passage 411 through the annular passage 412 and the rotating body 42.

  A passage detection sensor 301 is attached to the housing 41 in order to detect that the blade 422 has passed through a predetermined angular position (predetermined position) in the housing 41. The passage detection sensor 301 detects that the blade 422 has passed in front of the detection unit of the passage detection sensor 301. In the present embodiment, the passage detection sensor 301 is disposed on the housing 41 so as to face the radial end surface 422a of the blade 422 of the rotating body 42 and to be substantially parallel to the normal direction of the radial end surface 422a of the blade 422. It is attached.

  The output value of the passage detection sensor 301 is input to the amplifier unit 300. The amplifier unit 300 includes an amplifier that amplifies the output value of the passage detection sensor 301, and a CPU (microprocessor) that performs various calculations such as calculation of the angular velocity of the rotating body 42 using the output value amplified by the amplifier. It is an integrated one. In the present embodiment, the passage detection sensor 301 and the amplifier unit 300 are separated from each other, but the passage detection sensor 301 may be built in, and the passage detection sensor 301 and the amplifier unit 300 may be integrated.

  In the present embodiment, an eddy current sensor is used as the passage detection sensor 301. The eddy current sensor is a sensor that outputs a voltage value corresponding to the distance between the sensor detection unit and the metal material to be measured. The detection principle of the eddy current sensor will be briefly described below with reference to FIG.

  The eddy current sensor has a coil 301a that generates a magnetic field by an alternating excitation current in its detection unit. When the blade 422 passes through the magnetic field X generated by the coil 301a, an eddy current Y is generated in the blade 422 so as to cancel the magnetic field generated by the coil 301a. The strength of the magnetic field X changes due to the eddy current generated in the blade 422, and as a result, the value of the current flowing through the coil 301a changes. Therefore, it is possible to detect whether or not the blade 422 has passed by detecting a change in voltage value caused by a change in the current value flowing through the coil 301a by the eddy current sensor. Specifically, when the output value of the eddy current sensor reaches a peak, the blade 422 passes in front of the detection unit of the eddy current sensor 5 (that is, a predetermined angular position in the housing 41). Can be determined.

  As the passage detection sensor 301 for detecting the passage of the blade 422, any sensor may be used as long as the passage of the blade 422 can be detected. An example of such a sensor is an electromagnetic pickup (MPU) sensor. The MPU sensor is a sensor having a magnet and a detection coil in its detection unit. In such an MPU sensor, when a blade, which is a magnetic body, approaches or separates from the MPU sensor, the magnetic flux penetrating the detection coil changes, and the induced electromotive force of the detection coil changes accordingly. Thereby, the passage of the blade 422 in front of the detection unit of the MPU sensor can be detected. In the following description, a case where an eddy current sensor is used as the passage detection sensor 301 will be described.

  4A and 4B are diagrams showing transition of an output value (voltage value) of the passage detection sensor 301 when an eddy current sensor is used as the passage detection sensor 301. FIG. 4A shows the transition of the output value when the angular speed of the rotating body 42 is relatively slow (for example, the rotational speed of the rotating body 42 is 200,000 [rpm]), and FIG. 4B shows the case where the angular speed of the rotating body 42 is relatively fast. The transition of the output value at each time (for example, the rotational speed of the rotating body 42 is 400,000 [rpm]) is shown.

  When an eddy current sensor is used as the passage detection sensor 301, the output value increases as the distance between the detection unit of the passage detection sensor 301 and the object (blade 422 in the present embodiment) passing in front of the detection portion decreases. Therefore, when the blade 422 passes in front of the detection unit of the passage detection sensor 301, the output value of the passage detection sensor 301 increases rapidly. Therefore, the output changed into a convex shape in FIGS. 4A and 4B means that the blade 422 has passed. The numbers B1 to B12 in FIGS. 4A and 4B are the numbers of the blades 422 that have passed in front of the detection unit of the passage detection sensor 301.

  As shown in FIG. 4A, when the angular velocity of the rotating body 42 is relatively low, the output value of the passage detection sensor 301 increases and decreases rapidly as the blade 422 passes, and two adjacent blades 422 The period during which passes is kept constant at a low value.

  On the other hand, as shown in FIG. 4B, when the angular velocity of the rotating body 42 is relatively high, the output value of the passage detection sensor 301 that has risen along with the passage of one blade 422 is reduced before the next blade. With the passage of 422, the output value of the passage detection sensor 301 starts to rise. Therefore, as shown in FIG. 4B, the output value of the passage detection sensor 301 is not maintained constant even during the period during which two adjacent blades 422 pass. However, even in this case, since the time when the output value of the passage detection sensor 301 is maximum indicates the passage of the blade 422, the blade 422 has passed in front of the detection unit of the passage detection sensor 301. Can be accurately detected.

<Example of Calculation Method of Angular Velocity of Rotating Body Using Passage Detection Sensor>
In this way, the passage detection sensor 301 can accurately detect that the blade 422 has passed in front of the detection unit of the passage detection sensor 301. Therefore, as an example of a method for calculating the angular velocity of the rotating body 42 using the passage detection sensor 301, an arbitrary one of the blades 422 (hereinafter referred to as “reference blade”) passes in front of the passage detection sensor 301. After that, each time each blade 422 passes in front of the passage detection sensor 301 based on the time interval until the blade passing in front of the passage detection sensor 301 next to the reference blade, A method for calculating the angular velocity is mentioned.

  Below, with reference to FIG. 4A, an example of the calculation method of the angular velocity of the rotary body 42 using this passage detection sensor 301 is demonstrated.

  In the example shown in FIG. 4A, the time t1 is the time when the output value of the passage detection sensor 301 shows a peak due to the first blade B1 passing in front of the passage detection sensor 301. Similarly, when the second blade B2, the third blade B3, and the fourth blade B4 pass in front of the passage detection sensor 301 and the output value of the passage detection sensor 301 shows a peak, times t2, t3, and t4, respectively. To do.

  In this case, the time interval Δt1 from the passage of the first blade B1 to the passage of the second blade B2 in front of the passage detection sensor 301 is t2-t1. On the other hand, in the present embodiment, since 12 blades are provided at equal intervals, the angular interval between the first blade B1 and the second blade B2 is basically (2π / 12) [rad]. . Accordingly, the instantaneous angular velocity of the rotating body 42 from when the first blade B1 passes through the passage detection sensor 301 to when the second blade B2 passes (hereinafter referred to as “instantaneous angular velocity after passing through the first blade”). .) Ω1 [rad / s] is 2π / (12 × Δt1).

  Similarly, the time interval Δt2 from the passage of the second blade B2 to the passage of the third blade B3 in front of the passage detection sensor 301 is t3-t2, and after the passage of the third blade B3, the fourth blade B4. The time interval Δt3 until passes is t4-t3. Accordingly, the instantaneous angular velocity ω2 of the rotating body 42 from when the second blade B2 passes before the passage detection sensor 301 to when the third blade B3 passes, that is, the instantaneous angular velocity ω2 after passing through the second blade is 2π / (12 × Δt2). Similarly, the instantaneous angular velocity ω3 of the rotating body 42 from the passage of the third blade B3 to the passage of the fourth blade B4 in front of the passage detection sensor 301, that is, the instantaneous angular velocity ω3 after passing the third blade. Is 2π / (12 × Δt3).

  Therefore, if the number of the blade 422 is represented by i, the pair of adjacent blades 422 (that is, the i-th blade Bi and the (i + 1) -th blade B (i + 1)) based on the output of the passage detection sensor 301 is the passage detection sensor 301. Is calculated, the instantaneous angular velocity ωi after passing through the i-th blade Bi is calculated based on the time interval Δti and the angular interval between the pair of adjacent blades 422. be able to.

  Specifically, as shown in the following formula (1), the angular interval αi between adjacent pairs of blades 422 is divided by the time interval Δti that passes between these blades 422 to instantaneously pass through the i-th blade. A precise angular velocity ωi can be calculated.

  ωi = αi / Δti (1)

  Further, as in the present embodiment, when the blades 422 are rotating bodies 42 provided at equal intervals in the circumferential direction, the angular interval αi is (2π / p), where p is the total number of blades 422. Become. Therefore, the instantaneous angular velocity ωi after passing through the i-th blade can be calculated by the following equation (2).

  ωi = 2π / (p × Δti) (2)

  However, when the angular velocity of the rotating body 42 is calculated by such a calculation method, that is, after the reference blade passes in front of the passage detection sensor 301, the blade passes in front of the passage detection sensor 301 next to the reference blade. When the angular velocity of the rotating body 42 is calculated based on the time interval Δti until it passes, it has been found that an error (calculation error) occurs between the actual angular velocity and the calculated angular velocity.

<Blade shape error>
FIG. 5 is a diagram illustrating an example of a calculation result when the angular velocity of the rotating body 42 is calculated by the above-described calculation method when the rotating body 42 is rotated at a constant angular velocity. In FIG. 5, the horizontal axis represents the number of the blade 422, and the vertical axis represents the instantaneous angular velocity of the rotating body 42 after passing through the blade of the corresponding blade number.

  In the example shown in FIG. 5, the rotating body 42 is rotated at a constant angular velocity. Therefore, the instantaneous angular velocity of the rotating body 42 calculated at this time should be a constant value. However, actually, as shown in FIG. 5, the calculated instantaneous angular velocity of the rotating body 42 is not necessarily constant after passing through each blade 422. For example, in the example shown in FIG. 5, the instantaneous angular velocity of the rotating body 42 after passing through the second blade is slower than the instantaneous angular velocity of the rotating body 42 after passing through the first blade.

  As described above, one of the reasons why the calculated instantaneous angular velocity of the rotating body 42 does not become a constant value is a shape error of the blade 422 of the rotating body 42 (an error within a shape tolerance range). That is, each blade 422 of the rotating body 42 may have a shape error due to a manufacturing error or a secular change, and this shape error causes an error when the instantaneous angular velocity of the rotating body 42 is calculated. Hereinafter, the relationship between the calculated instantaneous angular velocity of the rotating body 42 and the shape error of the blade 422 will be described with reference to FIG.

  FIG. 6 is a schematic plan view of the rotating body 42 in which a shape error has occurred in the blade 422. 6 indicates the shape of the blade 422 when the blade 422 of the rotating body 42 is formed as designed. In the example shown in FIG. 6, it can be seen that the second blade B2 and the tenth blade B10 have a shape error with respect to the designed blade shape. Specifically, the second blade B2 has a shape shifted to the first blade side in the circumferential direction with respect to the design shape. Further, the tenth blade B10 has a shape shifted radially outward from the design shape.

  When an error occurs in the blade shape in this way, the angular interval α between the blades changes. In the example shown in FIG. 6, the shape of the second blade B2 is a shape shifted in the circumferential direction with respect to the designed shape. As a result, in the region facing the passage detection sensor 301, the actual angular interval between the first blade B1 and the second blade B2 is α1, which is smaller than the design value β1. Conversely, the actual angular interval between the second blade B2 and the third blade B3 is α2, which is larger than the design value β2. Accordingly, the actual angular interval α1 between the first blade B1 and the second blade B2 is smaller than the actual angular interval α2 between the second blade B2 and the third blade B3.

  On the other hand, in calculating the angular velocity, a design value is used instead of the actual angular interval between the blades. For this reason, even if the rotating body 42 rotates at a constant angular velocity, the instantaneous angular velocity ω1 of the rotating body 42 based on the time interval Δt1 from the first blade B1 to the second blade B2 is increased from the second blade B2 to the second blade B2. It is calculated as being faster than the instantaneous angular velocity ω2 of the rotating body 42 based on the time interval Δt2 to the three blades B3. As a result, as shown in FIG. 5, the instantaneous angular velocity after passing through the first blade B1 is calculated to be faster than the instantaneous angular velocity after passing through the second blade B2.

  In the example shown in FIG. 6, the tenth blade B <b> 10 has a shape shifted outward in the circumferential direction with respect to the design shape. As a result, the actual angular interval between the ninth blade B9 and the tenth blade B10 is α9 which is smaller than the design value β9. In addition, the actual angular interval between the tenth blade B10 and the eleventh blade B11 is α10 which is larger than the design value β10. As a result, even if the rotating body 42 rotates at a constant angular velocity, the instantaneous angular velocity after passing through the ninth blade B9 is calculated as being faster than the instantaneous angular velocity after passing through the tenth blade B10.

  FIG. 6 shows an example of a shape error in which the shape of the blade 422 is entirely shifted in the circumferential direction or the radial direction. However, the shape error generated in the blade 422 includes various errors other than the above-described shape errors, such as an error in the axial direction of the rotating body 42 and an error in the curved shape of the blade. If such a shape error occurs in the blade 422, the angular velocity of the rotating body 42 cannot be accurately calculated.

<Corresponding to calculation error caused by shape error>
Therefore, in the present embodiment, as in the calculation method described above, the time from when the reference blade passes in front of the passage detection sensor 301 until the blade that passes in front of the passage detection sensor 301 next to the reference blade passes. Rather than calculating the angular velocity of the rotating body 42 based on the interval, that is, the time required to pass between adjacent blades, the reference blade passes next to the passage detection sensor 301 and then the reference blade passes next. The angular velocity of the rotating body 42 is calculated based on the time interval until it passes in front of the detection sensor 301, that is, the time required for the rotating body 42 to make one rotation.

  By calculating the angular velocity of the rotating body 42 based on the time required for one rotation of the rotating body 42 in this way, even if a shape error occurs in the blade 422, the rotating speed is not affected by the shape error. The angular velocity of the body 42 can be calculated. For example, when the reference blade is the first blade B1, the actual angular interval α1 between the first blade B1 and the second blade B2 or the ninth blade B9 and the tenth blade B10 as in the example shown in FIG. Even if the actual angle interval α9 between the first blade B1 and the first blade B1 is different from the design values β1 and β9, the angle interval is always 2π [rad]. Even if the shape of the first blade B1 itself changes, the angular interval from the first blade B1 to the first blade B1 is always constant at 2π [rad].

  Therefore, by calculating the angular velocity of the rotating body 42 based on the time required for one rotation of the rotating body 42, the angular velocity of the rotating body 42 can be accurately calculated without being affected by the shape error of the blade 422. it can.

<Use of instantaneous angular velocity>
As a result of the inventors' diligent research, when the angular velocity of the rotating body 42 can be accurately calculated, the combustion state of each cylinder 4 of the engine body 1 is accurately determined based on the calculated angular velocity of the rotating body 42. It turned out to be able to be estimated. Hereinafter, a method for estimating the combustion state of each cylinder 4 of the engine body 1 based on the angular velocity of the rotating body 42 will be described.

<Calculation of kinetic energy of rotating body>
The rotating body 42 rotates inside the housing 41, and the kinetic energy KE of the rotating body 42 can be calculated by the following equation (3).

^{KE = I × ω 2/2} ... (3)

  In Expression (3), I is the moment of inertia of the rotating body 42, and ω is the angular velocity of the rotating body 42. The moment of inertia I of the rotating body 42 can be obtained in advance from the shape and material of the rotating body 42 by calculation or the like. Therefore, by obtaining the angular velocity of the rotating body 42, the kinetic energy of the rotating body 42 at the time when the angular velocity is obtained can be calculated.

  Therefore, in the present embodiment, during the operation of the internal combustion engine 100, the angular velocity ω of the rotating body 42 is calculated by the amplifier unit 300, and the kinetic energy of the rotating body 42 is calculated by the amplifier unit 300 according to Equation (3). In the present embodiment, since the angular velocity ω of the rotating body 42 can be accurately estimated without being affected by the shape error of the rotating body 42, the kinetic energy of the rotating body 42 can also be accurately calculated.

<Estimation of combustion state>
As described above, if the kinetic energy of the rotating body 42 can be accurately calculated, if the engine body 1 has a plurality of cylinders 4 based on the calculated kinetic energy, The combustion state of each cylinder 4 such as the combustion energy generated when the fuel is burned in the combustion chamber 6 and the combustion interval of each cylinder 4 can be estimated. If the engine body 1 is a single cylinder, the combustion state of the single cylinder such as the combustion energy and the combustion interval generated when the fuel is burned in the combustion chamber of the single cylinder can be estimated. Below, the relationship between the kinetic energy of the rotary body 42 and the combustion state of each cylinder 4 when the engine main body 1 has a plurality of cylinders 4 will be described.

  FIG. 7 is a diagram showing the transition of the angular velocity and kinetic energy of the rotating body 42 in one cycle of the internal combustion engine 100. The horizontal axis in the figure indicates the crank angle of the engine body 1. In FIG. 7, the solid line indicates the kinetic energy of the rotating body 42, and the broken line indicates the angular velocity of the rotating body 42.

  As shown in FIG. 7, the angular velocity of the rotating body 42 changes in accordance with the crank angle of the engine body 1. In the example shown in FIG. 7, first, when the exhaust valve of the first cylinder is opened and the exhaust gas flows out from the combustion chamber 6, the exhaust gas flowing into the annular passage 412 in the housing 41 increases. For this reason, the angular velocity of the rotating body 42 increases. Along with this, the kinetic energy of the rotating body 42 also increases.

  Thereafter, at the end of the exhaust stroke of the first cylinder, the flow rate of the exhaust gas flowing out from the combustion chamber 6 decreases. As a result, the angular velocity of the rotating body 42 decreases. Along with this, the kinetic energy of the rotating body 42 decreases.

  Therefore, as can be seen from FIG. 7, during the exhaust stroke of the first cylinder, the angular velocity of the rotating body 42 increases and then decreases, and accordingly, the kinetic energy of the rotating body 42 also increases and decreases. Further, such angular velocity and kinetic energy similarly change in the exhaust strokes of the other cylinders 4. Accordingly, in the four-cylinder internal combustion engine 100, the angular velocity and kinetic energy of the rotating body 42 fluctuate up and down largely four times per cycle of the internal combustion engine 100. That is, the angular velocity and kinetic energy of the rotating body 42 fluctuate up and down several times during one cycle of the internal combustion engine 100 according to the number of cylinders of the internal combustion engine 100.

  Here, taking the fourth cylinder as an example, the amount of increase in the kinetic energy of the rotating body 42 during the exhaust stroke of the fourth cylinder (ΔKE in FIG. 7) is the exhaust discharged from the combustion chamber 6 of the fourth cylinder. Is proportional to the exhaust energy. Similarly, the amount of increase in kinetic energy of the rotating body 42 during the exhaust strokes of the first cylinder, the third cylinder, and the second cylinder is discharged from the combustion chambers 6 of the first cylinder, the third cylinder, and the second cylinder, respectively. It is proportional to the exhaust energy of the exhaust. Here, the exhaust energy of the exhaust discharged from each cylinder 4 is basically based on the combustion energy generated when the fuel is burned in the combustion chamber 6 of each cylinder 4, that is, the combustion in the combustion chamber 6 of each cylinder 4. Proportional to generated torque (combustion torque).

  Therefore, the difference in combustion energy (combustion torque) between the cylinders can be detected by comparing the amount of increase in the kinetic energy of the rotating body 42 during the exhaust stroke of each cylinder 4 between the cylinders. Specifically, the difference (ΔKE) between the minimum value of the kinetic energy of the rotator 42 at the start of the exhaust stroke of each cylinder 4 and the maximum value of the kinetic energy of the rotator 42 during the exhaust stroke of the cylinder 4. Based on this, the difference in combustion energy (combustion torque) between the cylinders can be detected. The cylinder 4 having a large difference between the minimum value and the maximum value can be determined to be a cylinder 4 having a large combustion energy (combustion torque), and the cylinder 4 having a small difference between the minimum value and the maximum value has a combustion energy (combustion). It can be determined that the cylinder 4 has a small torque.

  Considering the fourth cylinder as an example, the time interval from the start of the exhaust stroke of the fourth cylinder to the end of the exhaust stroke (Δtcom in FIG. 7), that is, the rotating body 42 is discharged from the combustion chamber 6 of the fourth cylinder. The period during which the exhaust is rotated corresponds to the combustion interval from the start of the combustion stroke of the second cylinder to the end of the combustion stroke. Similarly, the time interval from the start of the exhaust stroke of the first cylinder, the third cylinder and the second cylinder to the end of the exhaust stroke is from the start of the combustion stroke of the third cylinder, the fourth cylinder and the first cylinder, respectively. This corresponds to the combustion interval until the end.

  Therefore, the difference in the combustion interval between the cylinders can be detected by comparing the time intervals from the start of the exhaust stroke of each cylinder 4 to the end of the exhaust stroke between the cylinders.

Thus, if the difference in combustion energy (combustion torque) and the difference in combustion interval between cylinders can be detected, parameters relating to combustion in each cylinder 4 such as fuel injection amount, intake air amount, ignition timing, etc. The control unit 200 can perform feedback control or feedforward control. Thereby, the difference of the combustion energy (combustion torque) between the cylinders and the difference of the combustion interval can be minimized.
If the engine body 1 is a single cylinder, the combustion state of the single cylinder such as the combustion energy (combustion torque) and the combustion interval of the single cylinder is calculated as needed, for example, in a steady state (no load fluctuation). When a difference occurs in the combustion state, the electronic control unit 200 performs feedback control and feedforward control on the parameters related to combustion of each cylinder 4 such as the fuel injection amount, the intake air amount, and the ignition timing so that the combustion states coincide. Can do.

<Calculation method of ΔKE and Δtcom>
FIG. 8 is a diagram illustrating a method for calculating the combustion energy ΔKE of each cylinder 4 and the combustion interval Δtcom of each cylinder 4. The horizontal axis in the figure indicates the crank angle of the engine body 1. The solid line in FIG. 8 indicates the kinetic energy of the rotating body 42, and the broken line indicates the angular velocity of the rotating body 42.

  In order to calculate the amount of increase in the kinetic energy of the rotating body 42 during the exhaust stroke of each cylinder 4, that is, the combustion energy ΔKE generated when fuel is burned in the combustion chamber 6 of each cylinder 4, the exhaust stroke of each cylinder 4 is calculated. It is necessary to calculate the minimum value of the kinetic energy of the rotator 42 at the start and the maximum value of the kinetic energy of the rotator 42 during the exhaust stroke of the cylinder 4.

  Here, taking the fourth cylinder as an example and considering the differential value (hereinafter referred to as “angular acceleration”) ω ′ (= dω / dt; the slope of the broken line in FIG. 8) of the rotating body 42, FIG. As shown, the angular acceleration ω ′ becomes 0 at the start of the exhaust stroke of each cylinder 4 at which the kinetic energy of the rotating body 42 becomes the minimum value (minimum value). In addition, the angular acceleration ω ′ becomes zero even at a certain point in the exhaust stroke of each cylinder 4 at which the kinetic energy of the rotating body 42 reaches the maximum value (maximum value).

Therefore, every time the angular velocity ω of the rotating body 42 is calculated, the amplifier unit 300 according to the present embodiment sets the angular velocity ω as the angular velocity current value ω _z of the rotating body 42 and sets the differential value of the angular velocity current value ω _z as the angular acceleration. This time, it calculates as value ω _z ′. Then, the amplifier unit 300 uses the angular velocity current value ω _z when the absolute value of the current angular acceleration current value ω _z ′ is equal to or less than a preset extreme value determination threshold value near 0 as the exhaust value of each cylinder 4. Angular velocity at the start of the stroke (hereinafter referred to as “minimum angular velocity”) ωL, or angular velocity at a certain point during the exhaust stroke of each cylinder 4 at which the kinetic energy of the rotating body 42 reaches the maximum value (maximum value) (hereinafter referred to as “maximum angular velocity”). Set as ωH.

In addition, regarding the angular velocity current value ω _z when the absolute value of the angular acceleration current value ω _z ′ is equal to or less than the extreme value determination threshold, whether the angular velocity current value ω _z is the minimum angular velocity ωL or the maximum angular velocity ωH. This determination can be made by determining whether or not the previous angular acceleration value ω _z−1 ′ calculated immediately before is a positive value.

Specifically, when the previous angular acceleration value ω _z−1 ′ is a negative value, that is, when the slope of the broken line in FIG. 8 is negative, it can be determined that the angular velocity changes from a decrease to an increase. Therefore, in this case, the amplifier unit 300 according to the present embodiment sets the angular velocity current value ω _z to the minimal angular velocity ωL when the absolute value of the angular acceleration current value ω _z ′ is equal to or less than the extreme value determination threshold. On the other hand, when the previous angular acceleration value ω _z−1 ′ is a positive value, that is, when the slope of the broken line in FIG. 8 is positive, it can be determined that the angular velocity ω changes from rising to falling. Therefore, in this case, the amplifier unit 300 according to the present embodiment sets the angular velocity current value ω _z when the absolute value of the angular acceleration current value ω _z ′ is equal to or less than the extreme value determination threshold value to the maximum angular velocity ωH.

  Substituting the minimal angular velocity ωL and the maximum angular velocity ωH set in this way into Equation (3), respectively, the minimum value of the kinetic energy of the rotating body 42 at the start of the exhaust stroke of each cylinder 4 and the exhaust of the cylinder 4 It is possible to calculate the maximum value of the kinetic energy of the rotating body 42 during the stroke. If the minimum value is subtracted from the maximum value of the kinetic energy calculated in this way, the combustion energy ΔKE generated when the fuel is burned in the combustion chamber 6 of each cylinder 4 can be calculated.

  Further, the combustion interval Δtcom of each cylinder 4 corresponds to the time interval from the start of the exhaust stroke of each cylinder 4 to the end of the exhaust stroke as described above. Therefore, the combustion interval Δtcom of each cylinder 4 coincides with the time from when the minimal angular velocity ωL is set until the next minimal angular velocity ωL is set. Therefore, the amplifier unit 300 according to the present embodiment calculates the combustion interval of each cylinder 4 by measuring the time from when the minimal angular velocity ωL is set to when the minimal angular velocity ωL is set next.

  In addition to this, for example, by calculating the time from when the minimum value of the kinetic energy of the rotating body 42 is calculated until the next time when the minimum value of the kinetic energy of the rotating body 42 is calculated, the combustion interval of each cylinder 4 is measured. Δtcom can also be calculated.

<Flowchart of combustion state estimation control>
Hereinafter, estimation control of the combustion energy of each cylinder 4 and the combustion interval of each cylinder 4 using the output value of the passage detection sensor 301 according to this embodiment will be described.

First, the angular velocity calculation control of the rotating body 42 performed by the amplifier unit 300 will be described with reference to FIG. The amplifier unit 300 repeatedly executes this routine at a predetermined calculation cycle (= sampling cycle t _smp ).

  In step S1, the amplifier unit 300 reads the output value of the passage detection sensor 301.

  In step S2, the amplifier unit 300 determines whether or not the elapsed time measurement start flag F1 is set to 0. The elapsed time measurement start flag F1 is a flag whose initial value is set to 0. When the elapsed time measurement start flag F1 is set to 0, the passage detection sensor 301 detects the passage of the blade 422. And 1 are set. And if the angular velocity and rotation speed of the rotary body 42 are estimated, it will return to 0 again. If the elapsed time measurement start flag F1 is set to 0, the amplifier unit 300 proceeds to the process of step S2. On the other hand, if the elapsed time measurement start flag F1 is set to 1, the amplifier unit 300 proceeds to the process of step S5.

  In step S3, the amplifier unit 300 determines whether or not the passage of the blade 422 is detected. The blade 422 whose passage has been detected in step S3 is an arbitrary one of a plurality of blades, that is, a reference blade. If the passage of the blade 422 is detected, the amplifier unit 300 proceeds to the process of step S4. On the other hand, if the passage of the blade 422 is not detected, the amplifier unit 300 ends the current process.

  In step S4, the amplifier unit 300 sets the elapsed time measurement start flag F1 to 1, and the elapsed time t after the reference blade passes in front of the detection unit of the passage detection sensor 301. _e1Start measuring.

In step S5, the amplifier unit 300 calculates a material obtained by integrating the sampling cycle _{t Smp} to the previous value of the elapsed time _{t e1} as elapsed time _{t e1.} It should be noted that the initial value of the elapsed time t _e is 0.

  In step S <b> 6, the amplifier unit 300 determines whether or not the passage of the blade 422 is detected by the passage detection sensor 301. If the passage detection sensor 301 detects the passage of the blade 422, the amplifier unit 300 proceeds to the process of step S7. On the other hand, if the overdetection sensor 5 does not detect the passage of the blade 422, the amplifier unit 300 ends the current process.

  In step S <b> 7, the amplifier unit 300 calculates the blade passage count i after the reference blade passes in front of the detection unit of the passage detection sensor 301. Specifically, the amplifier unit 300 calculates the blade passage number i by adding 1 to the previous value of the blade passage number i. Note that the initial value of the blade passage number i is 0.

  In step S8, the amplifier unit 300 determines whether or not the blade 422 that has detected passage in step S6 is a reference blade. Specifically, the amplifier unit 300 determines whether or not the blade passage number i is a value obtained by multiplying the total number of blades (12 in this embodiment) by a positive integer n.

  If the positive integer n is set to 1, for example, it can be determined whether or not the rotating body 42 has rotated once in step S8. If it is set to 2, for example, whether the rotating body 42 has rotated twice in step S8. It can be determined whether or not. That is, the timing for estimating the angular velocity of the rotating body 42 can be adjusted in accordance with the positive integer n, and the estimated number of angular velocity data of the rotating body 42 per unit time can be adjusted. In the present embodiment, the positive integer n is set to 1. However, the positive integer n may be set to a value larger than 1 in accordance with the calculation capability of the CPU of the amplifier unit 300.

  If the blade 422 whose passage has been detected in step S6 is the reference blade, the amplifier unit 300 proceeds to the process of step S9. On the other hand, the amplifier unit 300 ends the current process if the blade 422 whose passage has been detected in step S6 is not the reference blade.

  In step S9, the amplifier unit 300 determines that the elapsed time t calculated in step S5. _e1The reference blade passage time t_mSet as. In other words, since the positive integer n is set to 1 in the present embodiment, the amplifier unit 300 first detects that the reference blade has passed in front of the detection unit of the passage detection sensor 301, and then the reference unit. The time until the blade passes in front of the detection unit of the passage detection sensor 301 (the time required for the rotating body 42 to make one rotation) is the reference blade passage time t._mSet as.

In step S10, the amplifier unit 300, based on the reference blade passing time _{t m,} to calculate the angular velocity of the rotating body 42. Specifically, the amplifier unit 300 calculates the angular velocity ω of the rotating body 42 by substituting the reference blade passage time t _m into the following formula (4). Note In step S10, by substituting the reference blade passing time t _m the following equation (5), may be calculated together rotational speed N of the rotating body 42.

ω = 2π / t _m (4)
N = 60 / t _m (5)

In step S11, the amplifier unit 300 returns the elapsed time t _e1 , the blade passage number i, and the elapsed time measurement start flag F1 to the initial value 0.

Next, the estimation control of the combustion energy of each cylinder 4 of the engine body 1 performed by the amplifier unit 300 will be described with reference to FIG. The amplifier unit 300 repeatedly executes this routine at a predetermined calculation cycle (= sampling cycle t _smp ).

  In step S21, the amplifier unit 300 determines whether or not the angular velocity ω of the rotating body 42 is newly calculated by the above-described angular velocity calculation control of the rotating body 42. If the angular velocity ω of the rotating body 42 is newly calculated, the amplifier unit 300 proceeds to the process of step S22. On the other hand, the amplifier unit 300 ends the current process if the angular velocity ω of the rotating body 42 is not newly calculated.

In step S22, the amplifier unit 300 reads the angular velocity ω of the rotating body 42 which is newly calculated, and the reference blade passing time t _m that is used in the calculation, the.

  In step S23, the amplifier unit 300 determines whether there are two or more data of the angular velocity ω of the rotating body 42 read so far. If there are two or more data of the angular velocity ω of the rotating body 42 read so far, the amplifier unit 300 proceeds to the process of step S24. On the other hand, the amplifier unit 300 ends the current process if the data of the angular velocity ω of the rotating body 42 read so far is not two or more.

In step S24, the amplifier unit 300 calculates the angular acceleration current value ω _z ′ of the rotating body 42. Amplifier unit 300 Specifically, the angular velocity omega of the newly read rotator 42 now and angular current value omega _z of the rotating body 42, an angular velocity omega of the rotating body 42 is loaded before one time, The previous angular velocity ω _{z−1 of the} rotating body 42 is assumed. Then, the amplifier unit 300 substitutes the angular velocity current value ω _z , the angular velocity previous value ω _z−1, and the reference blade passage time t _m read in step S22 into the following formula (6), and the angular acceleration current value of the rotating body 42 is calculated. The value ω _z ′ is calculated.

ω _z ′ = (ω _z −ω _z−1 ) / t _m (6)

In step S25, the amplifier unit 300 determines whether or not the absolute value of the angular acceleration current value ω _z ′ of the rotating body 42 is equal to or less than the extreme value determination threshold value. If the angular acceleration current value ω _z ′ of the rotating body 42 is equal to or less than the extreme value determination threshold, the amplifier unit 300 proceeds to the process of step S26. On the other hand, if the angular acceleration current value ω _z ′ of the rotating body 42 is larger than the extreme value determination threshold, the amplifier unit 300 ends the current process.

In step S <b> 26, the amplifier unit 300 determines whether or not the previous angular acceleration value ω _{z −1} ′ of the rotating body 42 is a negative value. If the previous angular acceleration value ω _z−1 ′ of the rotating body 42 is a negative value, the amplifier unit 300 proceeds to the process of step S27. On the other hand, if the previous angular acceleration value ω _z−1 ′ of the rotating body 42 is a positive value, the amplifier unit 300 proceeds to the process of step S29.

In step S27, the amplifier unit 300 sets the angular velocity present value omega _z of the rotating body 42 set in step S24 as a minimum angular velocity .omega.L.

  In step S28, the amplifier unit 300 sets the flag F2 to 1. The flag F2 is a flag whose initial value is set to 0.

  In step S29, the amplifier unit 300 determines whether or not the flag F2 is set to 1. If the flag F2 is set to 1, the amplifier unit 300 proceeds to the process of step S30. On the other hand, if the flag F2 is set to 0, the current process is terminated.

In step S30, the amplifier unit 300 sets the angular velocity present value omega _z of the rotating body 42 set in step S24 as a maximum angular velocity .omega.H.

  In step S31, the amplifier unit 300 substitutes the minimum angular velocity ωL and the maximum angular velocity ωH set in step S27 and step S30 into the following equation (7) to increase the kinetic energy increase ΔKE of the rotating body 42, that is, the current exhaust gas. The combustion energy generated when the fuel is burned in the combustion chamber 6 of the cylinder 4 during the stroke is calculated.

ΔKE = I × {(ωH ² −ωL ² ) / 2} (7)

  In step S32, the amplifier unit 300 returns the flag F2 to the initial value 0.

Next, the estimation control of the combustion interval of each cylinder 4 of the engine body 1 performed by the amplifier unit 300 during the operation of the internal combustion engine 100 will be described with reference to FIG. The amplifier unit 300 repeatedly executes this routine at a predetermined calculation cycle (= sampling cycle t _smp ).

  In step S41, the amplifier unit 300 determines whether or not the flag F3 is set to 0. The flag F3 is a flag in which an initial value (a value at the start of operation of the internal combustion engine 100) is set to 0, and is set to 1 when the minimum angular velocity ωL is set for the first time after the operation of the internal combustion engine 100 is started. Is set. The flag F3 is returned to 0 when the internal combustion engine is stopped or started. If the flag F3 is set to 0, the amplifier unit 300 proceeds to the process of step S42. On the other hand, if the flag F3 is set to 1, the amplifier unit 300 proceeds to the process of step S44.

  In step S42, the amplifier unit 300 determines whether or not the minimum angular velocity ωL is set for the first time after the operation of the internal combustion engine 100 is started. Specifically, after the operation of the internal combustion engine 100 is started, the amplifier unit 300 proceeds to step S27 of the above-described combustion energy estimation control and determines whether or not the minimum angular velocity ωL is set. After the operation of the internal combustion engine 100 is started, the amplifier unit 300 proceeds to step S27 of the combustion energy estimation control described above for the first time, and proceeds to the process of step S43 if the minimum angular velocity ωL is set. On the other hand, after the operation of the internal combustion engine 100 is started, the amplifier unit 300 does not proceed to step S27 of the above-described combustion energy estimation control, and ends the current process if the minimum angular velocity ωL has not yet been set.

In step S43, the amplifier unit 300 sets the flag F3 to 1, and starts measuring the elapsed time _te2 after the angular velocity of the rotating body 42 becomes the minimal angular velocity.

  In step S44, the amplifier unit 300 determines that the elapsed time t_e2Sampling period t to the previous value of_smpElapsed time t_e2Calculate as The elapsed time t _e2The initial value of is 0.

  In step S45, the amplifier unit 300 determines whether or not the minimum angular velocity ωL has been updated. If the minimum angular velocity ωL has been updated, the amplifier unit 300 proceeds to the process of step S46. On the other hand, if the minimum angular velocity ωL has not been updated, the amplifier unit 300 ends the current process.

In step S46, the amplifier unit 300 calculates the elapsed time _{t e2} calculated in step S44 as a combustion distance Derutatcom.

In step 47, the amplifier unit 300 returns the elapsed time t _e2 to the initial value 0, and again starts measuring the elapsed time t _e2 after the angular velocity of the rotating body 42 becomes the minimum angular velocity.

  The combustion state estimation device 40 according to the present embodiment described above is rotatably accommodated in the housing 41 provided on the exhaust pipe 32 (exhaust path) of the engine body 1 having the cylinder 4 and at least one of them. A rotating body 42 that has a blade 422 and is rotationally driven by the energy of exhaust discharged from each cylinder 4 of the engine body 1, and is provided in the housing 41, and a predetermined position in the housing 41 is set at a predetermined position in the housing 41. Is detected based on the detection result of the passage detection sensor 301 and the passage detection sensor 301, and the angular velocity of the rotating body 42 is calculated, and the cylinder 4 of the engine body 1 is determined based on the angular velocity of the rotating body 42. An amplifier unit 300 (arithmetic unit) configured to calculate at least one of combustion energy and combustion interval.

  Therefore, according to the present embodiment, even if the in-cylinder pressure sensor is not provided, the combustion state estimating device 40 including the housing 41, the rotating body 42, the passage detection sensor 301, and the amplifier unit 300 is provided in the exhaust pipe 32, so that the engine At least one of the combustion energy or the combustion interval of the cylinder 4 of the main body 1 can be calculated.

  As a method for estimating the combustion energy of each cylinder 4, for example, an in-cylinder pressure sensor that detects the pressure in the combustion chamber 6 is provided for each cylinder 4, and based on the detection value of the in-cylinder pressure sensor, There is a method for calculating combustion energy. However, in this case, the same number of in-cylinder pressure sensors as the number of cylinders is required. Therefore, the estimation accuracy of the combustion energy of each cylinder 4 decreases due to individual variations in each cylinder pressure sensor. Furthermore, the degree of deterioration with time may be different for each in-cylinder pressure sensor, and as a result, the estimation accuracy of the combustion energy of each cylinder 4 further decreases with the passage of time.

  On the other hand, according to the present embodiment, as described above, each combustion state estimation device 40 is provided in the exhaust pipe 32, and the combustion energy of each cylinder 4 of the engine body 1 and the combustion interval of each cylinder 4 are changed. The combustion state of the cylinder can be estimated. For this reason, it is possible to accurately estimate the combustion state of each cylinder 4 while suppressing a decrease in the estimation accuracy of the combustion state of each cylinder 4 due to individual variation or aging.

  In addition, the amplifier unit 300 according to the present embodiment passes the elapsed time after any one of the blades 422 passes once through the predetermined position every time the arbitrary blade 422 passes through the predetermined position a predetermined number of times. The reference blade passing time is calculated, and the angular velocity of the rotating body 42 is calculated based on the reference blade passing time and the number of times any one blade 422 has passed a predetermined position during the reference blade passing time. The

  Therefore, the angular velocity of the rotating body 42 can be accurately calculated without being affected by the shape error of the blade 422 or aging. Therefore, the combustion energy of each cylinder 4 of the engine body 1 calculated based on the angular velocity of the rotating body 42 or the combustion interval of each cylinder 4 can be calculated with higher accuracy.

  In addition, the amplifier unit 300 according to the present embodiment calculates the angular acceleration that is a differential value of the angular velocity based on the angular velocity of the rotating body 42, and the absolute value of the angular acceleration is equal to or less than a predetermined extreme value determination threshold value. Based on the angular velocity of the rotating body 42, the combustion energy of the cylinder 4 during the exhaust stroke is calculated. More specifically, in the amplifier unit 300 according to the present embodiment, when the previous value of the angular acceleration is a negative value, the absolute value of the angular acceleration is equal to or less than a predetermined extreme value determination threshold. If the angular velocity is set as a minimal angular velocity and the previous value of the angular acceleration is a positive value, the angular velocity of the rotating body 42 when the absolute value of the angular acceleration falls below a predetermined extreme value determination threshold is set as the maximum angular velocity. The combustion energy of the cylinder 4 during the exhaust stroke is calculated based on the minimum angular velocity and the maximum angular velocity.

  Thus, according to the present embodiment, the combustion energy of each cylinder 4 can be accurately calculated from the angular velocity of the rotating body 42 calculated by the amplifier unit 300.

  The amplifier unit 300 according to the present embodiment is configured to calculate the combustion interval of the cylinder 4 based on a period from when the minimal angular velocity is set to when the minimal angular velocity is updated.

  Thus, according to the present embodiment, the combustion interval of the cylinder 4 can be accurately calculated from the angular velocity of the rotating body 42 calculated by the amplifier unit 300.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  In the above embodiment, the housing 41 of the combustion state estimation device 40 is provided upstream of the exhaust aftertreatment device 33 in the exhaust flow direction, but may be provided downstream.

  In the above embodiment, the internal combustion engine 100 is not provided with a supercharger (supercharger or turbocharger). However, the internal combustion engine provided with the supercharger is also provided with the combustion state estimation device 40, and the internal combustion engine 100 The combustion state of each cylinder may be estimated.

DESCRIPTION OF SYMBOLS 100 Internal combustion engine 1 Engine main body 41 Housing 42 Rotating body 422 Blade 300 Amplifier unit (arithmetic unit)
301 Passage detection sensor

Claims (5)

It is rotatably accommodated in a housing provided on an exhaust path of an engine body having a cylinder, and has at least one blade and is driven to rotate by energy of exhaust discharged from the cylinder of the engine body. A rotating body,
A passage detection sensor that is provided in the housing and detects that the blade of the rotating body has passed through a predetermined position in the housing;
The angular velocity of the rotating body is calculated based on the detection result of the passage detection sensor, and is an interval from the start of the combustion stroke of the cylinder of the engine body to the end of the combustion stroke based on the angular velocity of the rotating body. A computing device configured to calculate a combustion interval;
A combustion state estimation device comprising: The arithmetic unit is:
Based on the angular velocity of the rotating body, calculate an angular acceleration that is a differential value of the angular velocity,
If the previous value of the angular acceleration is a negative value, the angular velocity of the rotating body when the absolute value of the angular acceleration is equal to or less than a predetermined extreme value determination threshold is set as a minimal angular velocity,
If the previous value of the angular acceleration is a positive value, the angular velocity of the rotating body when the absolute value of the angular acceleration is equal to or less than a predetermined extreme value determination threshold is set as a maximum angular velocity,
It is configured to calculate the combustion interval based on a period from when the minimal angular velocity is set to when the minimal angular velocity is updated.
The combustion state estimation apparatus according to claim 1. The arithmetic device further includes:
Based on the minimum angular velocity and the maximum angular velocity, the combustion energy of the cylinder during the exhaust stroke is calculated.
The combustion state estimation device according to claim 2. It is rotatably accommodated in a housing provided on an exhaust path of an engine body having a cylinder, and has at least one blade and is driven to rotate by energy of exhaust discharged from the cylinder of the engine body. A rotating body,
A passage detection sensor that is provided in the housing and detects that the blade of the rotating body has passed through a predetermined position in the housing;
An arithmetic unit configured to calculate an angular velocity of the rotating body based on a detection result of the passage detection sensor, and to calculate combustion energy of a cylinder of the engine body based on the angular velocity of the rotating body;
A combustion state estimation device comprising:
The arithmetic unit is:
Based on the angular velocity of the rotating body, calculate an angular acceleration that is a differential value of the angular velocity,
If the previous value of the angular acceleration is a negative value, the angular velocity of the rotating body when the absolute value of the angular acceleration is equal to or less than a predetermined extreme value determination threshold is set as a minimal angular velocity,
If the previous value of the angular acceleration is a positive value, the angular velocity of the rotating body when the absolute value of the angular acceleration is equal to or less than a predetermined extreme value determination threshold is set as a maximum angular velocity,
Based on the minimum angular velocity and the maximum angular velocity, the combustion energy of the cylinder during the exhaust stroke is calculated.
Combustion state estimation device. The arithmetic unit is:
An elapsed time after any one of the blades passes the predetermined position once, and calculates as a reference blade passage time each time the arbitrary one blade passes the predetermined position,
Based on the reference blade passage time and the number of times the arbitrary one blade has passed the predetermined position during the reference blade passage time, the angular velocity of the rotating body is calculated.
The combustion state estimation device according to any one of claims 1 to 4.

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