JP5843937B1 - Control device for internal combustion engine - Google Patents

Abstract

In an internal combustion engine having a plurality of cylinders, an internal combustion engine control apparatus capable of accurately estimating the combustion state of each cylinder is provided. Alternatively, the first crank angle sensor and the second crank angle sensor are arranged so as to detect the angular position of the crankshaft across a plurality of cylinders, and the crank angle position and the crank angular acceleration obtained from these crank angle sensors are arranged. Based on this, the torque of the combustion cylinder is estimated by estimating the crank angle position and crank angular acceleration of each cylinder. [Selection] Figure 2

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that optimizes a combustion state by estimating an in-cylinder pressure of the internal combustion engine.

  In order to improve the fuel consumption performance and emission performance of the internal combustion engine, a method of controlling the combustion state of the internal combustion engine and feeding back the measurement result is effective. For that purpose, it is important to accurately measure the combustion state of the internal combustion engine. It is widely known that the combustion state of an internal combustion engine can be accurately measured by measuring the in-cylinder pressure. Conventionally, for example, Patent Literature 1 discloses a combustion state estimation device that estimates a combustion state from an output signal of a crank angle sensor.

Japanese Patent No. 5026334

  However, in an internal combustion engine having a plurality of cylinders, the combustion gas pressure torque of these cylinders is intermittently transmitted to the crankshaft. On the other hand, since the crankshaft is not a rigid body but an elastic body, torsional vibration is generated in the crankshaft. Therefore, the crank angle position of the crankshaft measured by the crank angle sensor and the crank angular velocity and crank angle acceleration calculated from the time when the crank angle position is input to the control device are each affected by torsional vibration. . In Patent Document 1, since the crankshaft is handled as a rigid body, the measured combustion state is not necessarily accurate under a condition in which torsional vibration is generated on the crankshaft.

  The present invention has been made in order to solve the above-described problems in a conventional control device for an internal combustion engine, and accurately estimates the combustion state of each cylinder in an internal combustion engine having a plurality of cylinders. An object of the present invention is to provide a control device for an internal combustion engine.

An internal combustion engine control apparatus according to the present invention includes:
A control device for an internal combustion engine comprising a plurality of cylinders having pistons coupled to a crankshaft,
A first crank for detecting a crank angle position at a different position in the axial direction of the crankshaft by sandwiching one or more of the cylinders to be estimated for a combustion state in the axial direction of the crankshaft An angle sensor and a second crank angle sensor;
A first crank angle position inputted from the first crank angle sensor, a time when the first crank angle position is inputted, and a second crank angle position inputted from the second crank angle sensor; Crank angle signal input time storage means for storing the time at which the second crank angle position is input;
Based on the time data stored in the crank angle signal input time storage means, a first crank angular acceleration corresponding to the first crank angle position and a second crank corresponding to the second crank angle position. Crank angular acceleration calculating means for calculating angular acceleration;
Based on the first crank angle position, the first crank angular acceleration, the second crank angle position, and the second crank angular acceleration, the crank angle positions and crank angular accelerations of the plurality of cylinders are estimated. Crank angle information estimating means for detecting, a cam angle sensor for detecting a cam angle of a camshaft connected to the crankshaft,
Combustion cylinder determining means for determining a combustion cylinder in a combustion state among the plurality of cylinders based on a cam angle signal from the cam angle sensor;
Non-combustion cylinder torque setting means for setting an estimated torque of a cylinder other than the combustion cylinder;
Combustion cylinder torque estimating means for estimating torque of the combustion cylinder based on crank angle positions and crank angular accelerations of the plurality of cylinders estimated by the crank angle information estimating means;
Combustion cylinder pressure estimation means for estimating the cylinder pressure of the combustion cylinder based on the torque estimated by the combustion cylinder torque estimation means;
It is provided with.

  According to the control apparatus for an internal combustion engine of the present invention, one or more cylinders among cylinders whose combustion states are to be estimated are sandwiched in the axial direction of the crankshaft, and cranks at different positions in the axial direction of the crankshaft are arranged. A first crank angle sensor and a second crank angle sensor for detecting an angular position, and a first crank angle position and a first crank angle position inputted from the first crank angle sensor are inputted. A crank angle signal input time storage means for storing a time, a second crank angle position input from the second crank angle sensor, and a time at which the second crank angle position is input, and the crank angle signal. Based on the time data stored in the input time storage means, the first crank angular acceleration corresponding to the first crank angle position, and the second Crank angular acceleration calculating means for calculating a second crank angular acceleration corresponding to the crank angular position; the first crank angular position; the first crank angular acceleration; the second crank angular position; Crank angle information estimating means for estimating the crank angle position and crank angular acceleration of the plurality of cylinders based on the crank angular acceleration of the plurality of cylinders; a cam angle sensor for detecting a cam angle of a camshaft connected to the crankshaft; And a non-combustion cylinder for setting an estimated torque of a cylinder other than the combustion cylinder, and a combustion cylinder determination means for determining a combustion cylinder in a combustion state among the plurality of cylinders based on a cam angle signal from the cam angle sensor Cylinder torque setting means and crank angle positions and cranks of the plurality of cylinders estimated by the crank angle information estimating means Combustion cylinder torque estimating means for estimating the torque of the combustion cylinder based on angular acceleration, and combustion cylinder pressure estimating means for estimating the cylinder pressure of the combustion cylinder based on the torque estimated by the combustion cylinder torque estimating means Therefore, it is possible to provide a control device for an internal combustion engine that can accurately estimate the combustion state of each cylinder.

It is a block diagram which shows the structure of the control apparatus of the internal combustion engine by Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 of this invention. It is a block diagram which shows the basic composition of the combustion cylinder pressure estimation process part in the control apparatus of the internal combustion engine by Embodiment 1 of this invention. 7 is a flowchart showing a flow of processing for estimating a combustion cylinder pressure in the control apparatus for an internal combustion engine according to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment of the present invention. It is explanatory drawing which shows the accumulation | storage state of the crank angle position detection time in the control apparatus of the internal combustion engine by Embodiment 1 of this invention. 4 is a graph showing transition of crank angle position detection time in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 7 is a flowchart showing a flow of processing in a crank angular acceleration calculating means in the control apparatus for an internal combustion engine according to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment of the present invention. 6 is a flowchart showing a flow of processing for calculating an angular velocity with respect to a first crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 5 is a flowchart showing a flow of processing for calculating a crank angular acceleration with respect to a first crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 5 is a flowchart showing a flow of processing for calculating a crank angular velocity with respect to a second crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 6 is a flowchart showing a flow of processing for calculating a crank angular acceleration with respect to a second crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. It is explanatory drawing of the crankshaft model for demonstrating the control apparatus of the internal combustion engine by Embodiment 1 of this invention. 6 is a flowchart showing a flow of processing in crank angle information estimation means in the control apparatus for an internal combustion engine according to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment of the present invention. 4 is a flowchart showing a flow of processing for estimating a crank angle position of a combustion cylinder corresponding to a first crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 4 is a flowchart showing a flow of processing for estimating a crank angular velocity of a combustion cylinder corresponding to a first crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 4 is a flowchart showing a flow of processing for estimating a crank angular acceleration of a combustion cylinder corresponding to a first crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 7 is a flowchart showing a flow of processing for estimating a crank angle position of a combustion cylinder corresponding to a second crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 4 is a flowchart showing a flow of processing for estimating a crank angular velocity of a combustion cylinder corresponding to a second crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 7 is a flowchart showing a flow of processing for estimating a crank angular acceleration of a combustion cylinder corresponding to a second crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 3 is a flowchart showing a flow of processing for estimating the torque of a combustion cylinder in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. It is explanatory drawing which shows the dynamic relationship of a piston crank system in the control apparatus of the internal combustion engine by Embodiment 1 of this invention. 6 is a flowchart showing a flow of processing for estimating a combustion cylinder pressure in the control apparatus for an internal combustion engine according to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment of the present invention. It is a block diagram which shows the basic conceptual structure of the combustion cylinder pressure estimation process part in the control apparatus of the internal combustion engine by Embodiment 2 and Embodiment 3 of this invention. 6 is a flowchart showing a flow of processing for estimating the torque of a combustion cylinder in the control apparatus for an internal combustion engine according to Embodiment 2 and Embodiment 3 of the present invention. It is a block diagram which shows the fundamental conceptual structure of the combustion cylinder pressure estimation process part in the control apparatus of the internal combustion engine by Embodiment 4 of this invention. It is a flowchart which shows the flow of the process which estimates the torque of a combustion cylinder in the control apparatus of the internal combustion engine by Embodiment 4 of this invention.

A preferred embodiment of an internal combustion engine control apparatus according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing the configuration of a control device for an internal combustion engine according to Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 of the present invention. In FIG. 1, an internal combustion engine 1 is a four-cylinder internal combustion engine having four cylinders, a first cylinder # 1, a second cylinder # 2, a third cylinder # 3, and a fourth cylinder # 4. The pressure of the combustion gas generated in each of the first cylinder # 1, the second cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4 is received by the upper surface of the piston 20 and is connected via the connecting rod 21. This is transmitted to the crankshaft 2 as power for rotating one crankshaft 2. The vehicle is driven based on the output torque output from the output side end of the crankshaft 2.

  The first crank angle sensor 3 is disposed in the vicinity of the peripheral surface of the first first signal rotor attached to the non-output side end that is the front end in the axial direction of the crankshaft 2. The first signal rotor 22 includes a plurality of protrusions disposed on the peripheral surface thereof with a predetermined angular interval. In the first crank angle sensor 3, each projection of the first signal rotor 22 for the first crank angle sensor 3 is changed to the first crank angle sensor 3 with the rotation of the first first signal rotor. A pulse-shaped first crank angle signal is generated and input to the control device 7 in response to the approach and separation. The control device 7 detects the angular position of the opposite end portion of the crankshaft 2 based on the first crank angle signal input from the first crank angle sensor 3.

  The second crank angle sensor 4 is disposed close to the peripheral surface of the second signal rotor 23 for the second crank angle sensor 4. And the 2nd 2nd signal rotor is provided with a plurality of projections arranged in the peripheral surface via predetermined angle intervals. The second crank angle sensor 4 is configured such that each protrusion of the second second signal rotor sequentially approaches and separates from the second crank angle sensor 4 as the second signal rotor 23 rotates. Correspondingly, a pulsed second crank angle signal is generated and input to the control device 7. The control device 7 detects the angular position of the output side end of the crankshaft 2 based on the second crank angle signal input from the second crank angle sensor 4.

  The first signal rotor 22 attached to the end on the opposite side of the crankshaft 2 and the second signal rotor 23 attached to the end on the output side of the crankshaft 2 are each configured integrally with the flywheel. ing. The number of protrusions disposed on each of the first signal rotor 22 and the second signal rotor 23, that is, the number of signals generated in one rotation of the internal combustion engine may be the same or different depending on the convenience of the layout. It may be.

  The camshaft 5 is connected to the crankshaft 2 by a chain 24, and the camshaft 5 rotates once while the crankshaft 2 rotates twice. The cam angle sensor 6 is arranged close to the peripheral surface of the third signal rotor 25 for the cam angle sensor attached to the camshaft 5. The third signal rotor 25 includes a plurality of protrusions disposed on the peripheral surface thereof with a predetermined angular interval. The cam angle sensor 6 generates a pulsed cam angle signal in response to the fact that each protrusion sequentially approaches and separates from the cam angle sensor 6 as the third signal rotor 25 rotates. Input to device 7. The control device 7 detects the cam angle position of the camshaft 5 based on the cam angle signal input from the cam angle sensor 6.

  The control device 7 is configured by an ECU (Electronic Control Unit). As described above, the first crank angle signal from the first crank angle sensor 3, the second crank angle signal from the second crank angle sensor 4, and the cam angle signal from the cam angle sensor 6, respectively. The cylinder pressures in the first cylinder # 1, the second cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4 are estimated based on the angle information. Although detailed description is omitted here, the control device 7 has a function of controlling the amount of fuel supplied to the internal combustion engine 1 and the ignition timing, and the internal combustion engine 1 is controlled based on the estimated in-cylinder pressure. Estimate the combustion states in the first cylinder # 1, the second cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4, and control the fuel amount and the ignition timing so that the ideal combustion state is obtained. By doing so, fuel efficiency and emission performance will be improved.

  Next, the configuration of the combustion cylinder pressure estimation processing unit provided in the control device 7 will be described. FIG. 2 is a block diagram showing a basic configuration of a combustion cylinder pressure estimation processing unit in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 2, a combustion cylinder pressure estimation processing unit 7A provided in the control device 7 includes a crank angle signal input time storage means 8, a crank angle acceleration calculation means 9, a crank angle information estimation means 10, and a combustion. Cylinder discrimination means 11, non-combustion cylinder torque setting means 12 included in crank angle information estimation means 10, combustion cylinder torque estimation means 13, and combustion cylinder pressure estimation means 14 are provided.

  The combustion cylinder discriminating means 11 receives the cam angle signal from the cam angle sensor 6 and the first crank angle signal from the first crank angle sensor 3 or the second crank angle signal from the second crank angle sensor 4. Based on this, the combustion cylinder is specified. Here, the combustion cylinder is defined as a cylinder in the latter half of the compression stroke to the first half of the expansion stroke in the four-cycle engine. Note that the specific method of the combustion cylinder is the same as the general ignition timing control of the internal combustion engine, and a detailed description thereof is omitted here.

  The crank angle signal input time storage means 8 corresponds to the combustion cylinder identified by the combustion cylinder discrimination means 11 and the crankshaft 2 counteracts based on the first crank angle signal inputted from the first crank angle sensor 3. The crank angle position of the output side end portion of the crankshaft 2 based on the time when the crank angle position of the output side end portion was detected and the second crank angle signal input from the second crank angle sensor 4 was detected. Time data consisting of time is accumulated for a predetermined period.

  Here, the predetermined period includes at least an in-cylinder pressure detection interval necessary for estimating the combustion state, that is, an interval from the latter half of the compression process of the combustion cylinder to the first half of the expansion stroke of the combustion cylinder. It may be accumulated longer. If the time at which the crank angle position is detected is accumulated for a period longer than the detection interval of the cylinder pressure, before the time data up to the first half of the latest cylinder expansion stroke is accumulated, the second half of the oldest cylinder expansion stroke is accumulated. Are deleted from the storage unit.

  The angular acceleration calculation means 9 is based on the time data accumulated in the crank angle signal input time storage means 8 and the angular positions of the above-mentioned projections respectively disposed on the first signal rotor 22 and the second signal rotor 23. Accordingly, the crank angular acceleration of the crankshaft 2 is calculated. That is, the first crank angular acceleration based on the first crank angle signal from the first crank angle sensor 3 and the second crank angular acceleration based on the second crank angle signal from the second crank angle sensor 4. Is calculated.

  The crank angle information estimation means 10 uses the first equation of motion calculated by the angular acceleration calculation means 9 and the first cylinder angular acceleration, and uses the first equation of motion to set the first cylinder. The crank angle position, crank angular velocity, and crank angular acceleration of each of # 1, second cylinder # 2, third cylinder # 3, and fourth cylinder # 4 are estimated.

  The non-combustion cylinder torque setting means 12 included in the crank angle information estimation means 10 specifies cylinders other than the current combustion from the currently-combusting cylinder information specified by the combustion cylinder discrimination means 11. For the equations of motion used to estimate the crank angle position and crank angular acceleration of each of the first cylinder # 1, the second cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4, Thus, the output torque of the non-combustion cylinders other than those during combustion is set to “0” or a sufficiently small value close to “0”.

  The combustion cylinder torque estimating means 13 inputs the crank angle position and the crank angle acceleration necessary for estimating the torque of the combustion cylinder from the crank angle information estimating means 10, and calculates an estimated value of torque for each crank angle position of the combustion cylinder. .

  The combustion cylinder pressure estimation means 14 uses the estimated value of torque for each crank angle position of the combustion cylinder calculated by the combustion cylinder torque estimation means 13, that is, the gas pressure received by the upper surface of the piston 20 of the combustion cylinder, that is, the cylinder pressure. Is estimated.

  Next, the processing flow of the combustion cylinder pressure estimation processing unit 7A in the control device 7 will be described in detail. FIG. 3 shows the flow of processing for estimating the pressure in the combustion cylinder in the control apparatus for an internal combustion engine according to the first embodiment of the present invention, and the second embodiment, the third embodiment, and the fourth embodiment described later. It is a flowchart. In FIG. 3, in step S301, the first crank angle position detected by the first crank angle sensor 3 and the second crank angle position detected by the second crank angle sensor 4 are detected. At the same time, it is stored in the crank angle signal input time storage means 8.

  Specifically, for the combustion cylinder determined by the combustion cylinder determination means 11, the time when the first crank angle position θ1 is detected with reference to the compression top dead center (hereinafter referred to as TDC) of this combustion cylinder. And the time when the second crank angle position θf is detected are stored. FIG. 4 is an explanatory view showing the accumulation state of the crank angle position detection time in the control apparatus for an internal combustion engine according to Embodiment 1 of the present invention, where (a) is the first crank angle position, (b ) Indicates the second crank angle position.

  In the control apparatus for an internal combustion engine according to the first embodiment of the present invention, the protrusion disposed on the first signal rotor 22 for the first crank angle sensor 3 and the second for the second crank angle sensor 4 are provided. The protrusions disposed on the signal rotor 23 are disposed at the same crank angle position of the same crankshaft 2 and are spaced by 6 [deg] from the TDC of the reference cylinder (for example, the first cylinder # 1). “60” pieces are arranged respectively. Therefore, the first crank angle position θ1 based on the first signal rotor 22 and the second crank angle position θf based on the second signal rotor 23 are respectively from the TDC of the reference cylinder (for example, the first cylinder # 1). “60” crank angle positions are provided at intervals of 6 [deg].

  The crank angle signal input time storage means 8 has both the first crank angle position θ1 and the second crank angle position θf as a section from the latter half of the compression process of the combustion cylinder to the first half of the expansion stroke of the combustion cylinder. The crank angle position from 90 [deg] to 90 [deg] after TDC is stored. The detection times t1 and tf of the respective crank angle signals are based on the crank angle position of the starting point (“0” [msec]) from the time when the signal 90 [deg] before the compression top dead center of the combustion cylinder is detected. Every time a subsequent crank angle signal is detected, the storage numbers “1” to “31” are stored as the elapsed time from the detection of the crank angle signal 90 [deg] before the compression top dead center as the starting point.

  FIG. 5 is a graph showing the transition of the crank angle position detection time in the control apparatus for an internal combustion engine according to the first embodiment of the present invention, which is stored in the crank angle signal input time storage means 8 shown in FIG. The first crank angle position detection time t1 and the second crank angle position detection time tf are plotted. As is apparent from the graph shown in FIG. 5, there is a difference between the detection times t1 and tf of the first crank angle position θ1 and the second crank angle position θf, regardless of the same crank angle position. You can see that This phenomenon shows a state in which torsional vibration is generated in the crankshaft 2.

  In other words, when the crankshaft 2 that is an elastic body is twisted, a difference occurs in the time until the counter-output side end and the output-side end of the crankshaft 2 reach the same crank angle position. For this reason, even if only the first crank angle position θ1 detected by the first crank angle sensor 3 is observed, the second cylinders # 1 other than the first cylinder # 1 adjacent to the first crank angle sensor 3 are observed. 2. Since the actual crank angle positions of the third cylinder # 3 and the fourth cylinder # 4 are different from the angle position θ detected by the first crank angle sensor 3, the in-cylinder pressure cannot be estimated accurately. Become.

  Returning to FIG. 3, in step S302, the crank angle acceleration calculation means 9 uses the time data stored in the crank angle signal input time storage means 8 to produce the first crank angular acceleration AA1 with respect to the first crank angle position θ1. And second crank angular acceleration AAF for the second crank angle position θf. Next, details of the processing in step S302 will be described. FIG. 6 shows the flow of processing in the crank angular acceleration calculation means in the control apparatus for an internal combustion engine according to the first embodiment of the present invention, and the second, third and fourth embodiments described later. It is a flowchart to show.

  In FIG. 6, first, in step S601, the first crank angular velocity AV1 for the first crank angle position θ1 is calculated, and in step S602, the first crank angular velocity AV1 is used to calculate the first crank angular velocity AV1. A first crank angular acceleration AA1 with respect to the crank angle position θ1 is calculated. Next, in step S603, a second crank angular speed AVF with respect to the second crank angle position is calculated, and in step S604, the second crank angular speed AVF is used to calculate the second crank angular speed AVF. 2 crank angular acceleration AAF is calculated.

  FIG. 7 is a flowchart showing a flow of processing for calculating an angular velocity with respect to the first crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In step S601 in FIG. Details of the process are shown. In FIG. 7, first, in step S701, a counter CNT indicating a value corresponding to the storage number for the first crank angle position θ1 is reset. Specifically, “2” is substituted into the counter CNT indicating the storage number of the first crank angle position θ1 shown in FIG. Next, in step S702, it is determined whether or not the end of the first crank angle position θ1 has been reached. Here, [P_NUM1] is the maximum value of the storage number of the first crank angle position θ1, and the storage number of the crank angle position corresponding to the end of the process is [P_NUM1-1].

  That is, the counter CNT indicating the storage number for calculating the first crank angular velocity AV1 with respect to the first crank angle position θ1 is from “2” to [P_NUM1-1]. In this way, the reason why the head portion and the rear end portion of the storage number are not processed is that the angular velocity is obtained by the center difference method described later. As a result of the determination in step S702, if it is determined that the value of the counter CNT indicating the storage number has not reached the end of the first crank angle position θ1 (NO), it is determined that the crank angular velocity to be calculated still remains. In step S703, the first crank angular velocity AV1 with respect to the first crank angular position θ1 is calculated. On the other hand, if it is determined in step S702 that the count value of the counter CNT indicating the storage number has reached the end of the first crank angle position θ1 (YES), the first crank angle position θ1 is determined. It is determined that the calculation of the first crank angular velocity AV1 is finished, and the process is finished.

In step S703, the first crank angular velocity AV1 with respect to the first crank angular position θ1 is calculated by the following equation (1) using the center difference method.
Here, θ1 (CNT) and t1 (CNT) indicate the crank angle position θ1 and time t1 accumulated in the storage number, respectively. Thereafter, the counter CNT indicating the storage number is incremented in step S704, and the process returns to step S702.

  Next, the first crank angular acceleration AA1 with respect to the first crank angular position θ1 is calculated using the first angular velocity AV1 calculated in step S703. This process is performed in step S602 in FIG. 6 as described above. Details of the processing in step S602 will be described below. FIG. 8 is a flowchart showing a flow of processing for calculating the first crank angular acceleration with respect to the first crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. As described above, the processing of step S601 in FIG. 6 calculates the crank angular velocity from the center difference of the first crank angle position θ1, whereas in step S602, the first crank angular velocity AV1 calculated in step S601. The first angular acceleration AA1 is calculated by using the center difference method in correspondence with the first crank angle position θ1.

  That is, in FIG. 8, first, the counter CNT indicating the storage number of the crank angle position processed in step S801 is reset. Here, “3” is substituted into the counter CNT indicating the storage number. Next, it is determined whether or not the end of the first crank angle position θ1 processed in step S802 has been reached. Here, the counter CNT of the first crank angle position θ1 corresponding to the end of the process is [P_NUM1-2]. That is, the counter CNT for calculating the first crank angular acceleration AA1 with respect to the first crank angle position θ1 is from “3” to [P_NUM1-2], and the first part and the rear end part of the storage number are not processed. This is because the storage number of the first crank angular velocity AV1 used to calculate the first crank angular acceleration AA1 exists only from [2] to [P_NUM1-1].

  As a result of the determination in step S802, if it is determined that the value of the counter CNT indicating the storage number has not reached the end of the first crank angle position θ1 (NO), the crank angular acceleration to be calculated still remains. In step S803, the first crank angular acceleration AA1 is calculated. On the other hand, if it is determined in step S802 that the count value of the counter CNT indicating the storage number has reached the end of the first crank angle position θ1 (YES), the first crank angle position θ1 is determined. It is determined that the calculation of the first crank angular acceleration AA1 is finished, and the process is finished.

Next, in step S803, the first crank angular acceleration AA1 with respect to the first crank angular position θ1 is calculated by the following equation (2) using the center difference method.
Thereafter, in step S804, the counter indicating the counter CNT is incremented, and the process returns to step S802.

  Next, details of the process of calculating the second crank angular velocity AVF for the second crank angle position θf in step S603 in FIG. 6 will be described. FIG. 9 is a flowchart showing a flow of processing for calculating the crank angular velocity with respect to the second crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 9, first, in step S901, the counter CNT indicating the storage number for the second crank angle position θf is reset. Specifically, the value “2” is substituted into the counter CNT indicating the storage number of the second crank angle position θf shown in FIG. Next, in step S902, it is determined whether the end of the second crank angle position θf has been reached. Here, [P_NUM2] is the maximum value of the storage number of the second crank angle position θf, and the storage number of the crank angle position corresponding to the end of the process is [P_NUM2-1].

  That is, the counter CNT indicating the storage number for calculating the second crank angular velocity AVF with respect to the second crank angle position θf is from “2” to [P_NUM2-1]. Thus, the reason why the first part and the rear part of the storage number are not processed is that the crank angular velocity is obtained by the central difference method described later. As a result of the determination in step S902, when it is determined that the value of the counter CNT indicating the storage number has not reached the end of the second crank angle position θf (NO), it is determined that the crank angular velocity to be calculated still remains. In step S903, the second crank angular velocity AVF with respect to the second crank angular position θf is calculated. On the other hand, if it is determined in step S902 that the count value of the counter CNT indicating the storage number has reached the end with respect to the second crank angle position θf (YES), the second value for the second crank angle position θf is determined. It is determined that the calculation of the crank angular velocity AVF is finished, and the process is finished.

In step S903, the second crank angular velocity AVF with respect to the second crank angle position θf is calculated by the following equation (3) using the center difference method.

Here, θf (CNT) and tf (CNT) indicate the second crank angle position θf and time tf accumulated in the storage number, respectively. Thereafter, in step S904, the counter CNT indicating the storage number is incremented, and the process returns to step S902.

  Next, the second angular acceleration AAF with respect to the second crank angle position θf is calculated using the second angular velocity AVF calculated in step S903. This processing is performed in step S604 in FIG. 6 as described above. Details of the processing in step S604 will be described below. FIG. 10 is a flowchart showing a flow of processing for calculating the second crank angular acceleration with respect to the second crank angle position in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. As described above, the processing of step S603 in FIG. 6 calculates the crank angular velocity from the center difference of the second crank angle position θf, whereas in step S604, the second crank angular velocity AVF calculated in step S603 is calculated. , The second angular acceleration AAF is calculated by the center difference method in correspondence with the second crank angle position θf.

  That is, in FIG. 10, first, in step S1001, the counter CNT indicating the storage number of the angular position to be processed is reset. Here, “3” is substituted into the counter CNT indicating the storage number. Next, it is determined whether or not the end of the second crank angle position θf processed in step S1002 has been reached. Here, the counter CNT of the second crank angle position θf corresponding to the end of the process is [P_NUM2-2]. That is, the counter CNT for calculating the second crank angular acceleration AAF with respect to the second crank angular position θf is [3] to [P_NUM2-2], and the first part and the rear end part of the storage number are not processed. This is because the storage number of the second crank angular velocity AVF used for calculating the second crank angular acceleration AAF exists only from [2] to [P_NUM2-1].

  As a result of the determination in step S1002, if it is determined that the value of the counter CNT indicating the storage number has not reached the end of the second crank angle position θf (NO), the angular acceleration to be calculated still remains. In step S1003, the second crank angular acceleration AAF is calculated. On the other hand, if it is determined in step S1002 that the count value of the counter CNT indicating the storage number has reached the end with respect to the second crank angle position θf (YES), the second value for the second crank angle position θf is determined. It is determined that the calculation of the crank angular acceleration AAF is finished, and the process is finished.

Next, in step S1003, the second crank angular acceleration AAF with respect to the second crank angular position θf is calculated by the following equation (4) using the center difference method.
Thereafter, the counter CNT indicating the storage number is incremented in step S1004, and the process returns to step S1002.

  Returning to FIG. 3, the description of the processing in the combustion cylinder pressure estimation processing unit 7A will be continued. In FIG. 3, in step S303, the crank angle information estimating means 10 uses the angular acceleration calculated by the crank angular acceleration calculating means 9 to correspond to each cylinder # 2, # 3, # 4 other than the first cylinder # 1. The crank angle position and crank angular acceleration to be estimated are estimated. Since the crankshaft 2 is an elastic body, the crankshaft 2 of the internal combustion engine 1 shown in FIG. 1 can be represented by the model shown in FIG. That is, FIG. 11 is an explanatory diagram of a crankshaft model for explaining the control apparatus for an internal combustion engine according to the first embodiment of the present invention.

In FIG. 11, Ij (j = 1, 2, 3, 4) is the inertia moment of the j-th cylinder, If is the inertia moment of the flywheel, kin (i = 1, 2, 3; n = 2, 3, 4) is the spring constant of the connecting part of the i-th cylinder and the n-th cylinder, and k4f is the spring constant of the connecting part of the fourth cylinder and the flywheel, which are constants determined at the time of design. Further, the torque generated in each cylinder is Tj (j = 1, 2, 3, 4), the crank angle position of the i-th cylinder is θi (i = 1, 2, 3, 4), and the angular acceleration of the i-th cylinder is
(I = 1, 2, 3, 4) When the load value applied to the internal combustion engine 1 is TL, the elastic body model of the crankshaft 2 is represented by the following relational expression.

The crank angle information estimation unit 10 uses the second angular acceleration AAF calculated by the crank angular acceleration calculation unit 9 from the above equation (4), and the equations (5), (6), (7), and ( 8) and the equation (9) are sequentially solved to determine the crank angle position θp (p = p) of the second cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4, which are cylinders other than the first cylinder # 1. Crank angular acceleration for 2, 3, 4)
(P = 2, 3, 4) is estimated.

The non-combustion cylinder torque setting means 12 determines a non-combustion cylinder based on the information on the combustion cylinder determined by the combustion cylinder determination means 11. For example, if the combustion cylinder is the second cylinder # 2, the non-combustion cylinder is a cylinder other than the second cylinder # 2, that is, the first cylinder # 1, the third cylinder # 3, and the fourth cylinder # 4 are non-combustion cylinders. judge. Subsequently, the torque of the non-combustion cylinder in Expressions (5), (6), (7), (8), and (9), which are relational expressions of the above-described elastic body model of the crankshaft 2, is “0”. To "". Specifically, [T1 = T3 = T4 = 0] is set. By doing so, the equation (5) can be transformed into the following equation (10).

The crank angle position θ2 of the second cylinder # 2 is determined by the crank angle position θ1 and the crank angular acceleration obtained by the first crank angle sensor 3 and the crank angular acceleration calculating means 9.
Is calculated from Here, the crank angle position θ2 of the second cylinder # 2 is described as θ2e1 so as to indicate that it is estimated from the combustion cylinder torque estimating means side, that is, from the opposite output side end portion of the crankshaft 2. To do.

Next, equation (9) is transformed into equation (11) below.

The angular position θ4 of the fourth cylinder # 4 includes the second crank angle position θf obtained by the second crank angle sensor 4 and the crank angular acceleration calculating means 9 and the second crank angular acceleration.
Is calculated from Note that TL is a load value applied to the internal combustion engine 1 as described above. For example, TL is a value that can be calculated based on the deceleration of the crankshaft 2 at a timing when no cylinder is combusted. The crank angle position θ4 of the fourth cylinder # 4 is described as θ4ef to indicate that it is estimated from the second crank angle sensor 4 side, that is, from the output side end of the crankshaft 2. .

Next, the above equation (8) is transformed into the following equation (12).

Therefore, the crank angle position θ3 of the third cylinder # 3 is θ4 in the equation (12),
, Θf, and can be solved.
Is calculated from the following equations (13) and (14) using the crank angle position θ4 of the fourth cylinder # 4 obtained by the equation (11).

  Here, CNT is a storage number of the second crank angle position detected by the second crank angle sensor 4. The estimated value of the crank angle position θ3 of the third cylinder # calculated in this way is described as θ3ef.

Next, the above equation (7) is transformed into the following equation (15).

Accordingly, the crank angle position θ2 of the second cylinder # 2 is θ3 in the equation (15),
, Θ4, and can be solved.
Is
Similarly to the above, it can be calculated from the difference method of the following equations (16) and (17).

  Here, the estimated value of the crank angle position θ2 of the second cylinder # 2 obtained by the equation (16) is described as θ2ef. As described above, regarding the estimated value of the crank angle position θ2 of the second cylinder # 2, it can be seen that there are two types of θ2e1 and θ2ef obtained from the above equations (10) and (15).

Finally, the two types of estimated values θ2e1 and θ2ef of the crank angle position θ2 of the second cylinder # 2 are substituted into θ2 in the following equations (18) and (19).
Is calculated.

Thus, the parameter group to be substituted into the equation (6), which is a relational expression for calculating the torque T2 of the combustion cylinder, is the first crank angle position θ1 detected by the first crank angle sensor 3 and the combustion. It was obtained by solving equations (5) to (9) sequentially from the opposite direction end of the crankshaft 2 to the cylinder and from the two directions from the output end.
, Θ2, and θ3 can all be obtained.

  Next, the flow of processing by the crank angle information estimation means 10 will be described. FIG. 12 shows the flow of processing in the crank angle information estimation means in the control apparatus for an internal combustion engine according to the first embodiment of the present invention, and the second, third and fourth embodiments described later. It is a flowchart to show. In FIG. 12, first, it is determined in step S1201 whether or not the combustion cylinder number CB obtained from the combustion cylinder discriminating means 11 is “1”, that is, whether the combustion cylinder is the first cylinder # 1 or not. If it is one cylinder # 1 (YES), it is determined that it is unnecessary to estimate the crank angle position, the crank angular velocity, and the crank angular acceleration from the first crank angle sensor 3 toward the output side end portion of the crankshaft 2. The process proceeds to step S1208.

On the other hand, if the result of determination in step S1201 is that the combustion cylinder is not the first cylinder # 1 (NO), the process proceeds to step S1202, and the cylinder number CQ for which the crank angle position, crank angular velocity, and crank angular acceleration are to be estimated is set. Set “2”. Next, proceeding to step S1203, the crank angle position θ _CQ is estimated. Next, the process in step S1203 will be described in detail. FIG. 13 is a flowchart showing a flow of processing for estimating the crank angle position of the combustion cylinder corresponding to the first crank angle sensor 3 in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. Details of the processing in step S1203 in FIG. 12 are shown.

  In FIG. 13, first, the counter CNT indicating the storage number of the crank angle position detected by the first crank angle sensor 3 in step S1301 is set to “1”. Next, in step S1302, it is determined whether or not the end of the crank angle position to be processed has been reached. Here, the storage number of the angular position corresponding to the end of the process is [P_NUM1]. As a result of the determination in step S1302, when it is determined that the end of the angular position to be processed has not been reached (NO), the process proceeds to step S1303 and the processing is continued, and it is determined that the end of the crank angle position to be processed has been reached. If yes (YES), the process ends.

In step S1303, the crank angle position corresponding to the value of the counter CNT indicating the storage number of the CQ cylinder is estimated. Here, in the case of [CQ = 2], the following formula (20) is used, and in the case of [CQ> 2], the following formula (21) is used. In step S1304, the counter CNT indicating the storage number is incremented, and the process returns to step S1302.

Next, in step S1204 in FIG.
Is estimated. Details of this processing are shown in FIG. That is, FIG. 14 is a flowchart showing a flow of processing for estimating the crank angular velocity of the combustion cylinder corresponding to the first crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 14, first, in step S1401, the counter CNT corresponding to the storage number of the crank angle position detected by the first crank angle sensor 3 is set to “2”. In step S1402, it is determined whether or not the end of the crank angle position to be processed has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is P_NUM1-1.

As a result of the determination in step S1402, if it is determined that the crank angle position storage number P_NUM1-1 corresponding to the end of the process has not been reached (NO), the process proceeds to step S1403 and the process is continued. When it is determined that the storage number [P_NUM1-1] of the corresponding crank angle position has been reached (YES), the process is terminated. In step S1403, the crank angular speed corresponding to the value of the counter CNT indicating the storage number of the CQ cylinder is estimated by the following equation (22).

Next, in step S1205 of FIG. 12, crank angular acceleration.
Is estimated. Details of this processing are shown in FIG. That is, FIG. 15 is a flowchart showing a flow of processing for estimating the crank angular acceleration of the combustion cylinder corresponding to the first crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 15, first, “3” is set to the counter CNT indicating the storage number of the first crank angle position detected by the first crank angle sensor 3 in step S1501. Next, in step S1502, it is determined whether or not the end of the crank angle position to be processed has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is [P_NUM1-2].

If it is determined in step S1502 that the storage number [P_NUM1-2] of the crank angle position corresponding to the end of the process has not been reached (NO), the process proceeds to step S1503 and the process is continued. When it is determined that the storage number [P_NUM1-2] of the crank angle position corresponding to the terminal end has been reached (YES), the process ends. In step S1503, the crank angular acceleration corresponding to the value of the counter CNT indicating the storage number of the CQ cylinder is estimated by the following equation (23).

  Next, in step S1206 of FIG. 12, the cylinder number CQ is incremented. In step S1207, it is determined whether or not the cylinder number CQ has reached the combustion cylinder CB. If the cylinder number CQ has reached the combustion cylinder CB (YES), the output of the crankshaft 2 from the first crank angle sensor 3 is determined. It is determined that the estimation of the crank angle position, the crank angular velocity, and the crank angular acceleration in the direction of the side end is complete, and the process proceeds to step S1208. If the cylinder number CQ has not reached the combustion cylinder CB (NO), the process proceeds to step S1203. Return.

  Next, the crank angle position, the crank angular velocity, and the crank angular acceleration in the direction from the second crank angle sensor 4 toward the non-output side end of the crankshaft 2 are estimated. In FIG. 12, in step S1208, m is set to the cylinder number CQ for which the crank angle position, crank angular speed, and crank angular acceleration are to be estimated. Here, m is the total number of cylinders of the internal combustion engine 1.

Next, the crank angle position θ _CQ is estimated in step S1209. Details of this processing are shown in FIG. That is, FIG. 16 is a flowchart showing the flow of processing for estimating the crank angle position of the combustion cylinder corresponding to the second crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 16, first, in step S1601, the counter CNT indicating the storage number of the second crank angle position detected by the second crank angle sensor 4 is set to “1”.

  Next, in step S1602, it is determined whether or not the end of the crank angle position to be processed has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is [P_NUM2]. If it is determined that the crank angle position storage number [P_NUM2] corresponding to the end of the crank angle position processed in step S1602 has not been reached (NO), the process proceeds to step S1603 and the process is continued to end the crank angle position to be processed. If it is determined that the storage number [P_NUM2] of the crank angle position corresponding to is reached (YES), the process is terminated.

In step S1603, the crank angle position corresponding to the value of the counter CNT indicating the storage number of the CQ cylinder is estimated. Here, for estimation of the crank angle position, the following formula (24) is used in the case of [CQ = m], and the following formula (25) and [CQ <m in the case of [CQ = m−1]. -1], the following equation (26) is used.

Next, the process proceeds to step S1604, the counter CNT is incremented, and the process returns to step S1602.

Returning to FIG. 12, in step S1210, the crank angular velocity.
Is estimated. Details of this processing are shown in FIG. FIG. 17 is a flowchart showing a flow of processing for estimating the crank angular velocity of the combustion cylinder corresponding to the second crank angle sensor in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 17, first, in step S1701, the counter CNT corresponding to the second crank angle position θf storage number detected by the second crank angle sensor 4 is set to “2”.

  Next, it is determined whether or not the end of the crank angle position processed in step S1702 has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is [P_NUM1-1]. If it is determined that the end of the crank angle position processed in step S1702 has not been reached (NO), the process proceeds to step S1703 to continue the process, and if it is determined that the end of the crank angle position to be processed has been reached (YE ) Terminates the process.

In step S1703, the crank angular speed corresponding to the value of the counter CNT indicating the storage number of the CQ cylinder is estimated based on the following equation (27).

Returning to FIG. 12, in step S1211, the crank angular acceleration is obtained.
Is estimated. Details of this processing are shown in FIG. FIG. 18 is a flowchart showing the flow of processing for estimating the crank angular acceleration of the combustion cylinder corresponding to the second crank angle sensor in the internal combustion engine control apparatus according to Embodiment 1 of the present invention. In FIG. 18, first, in step S1801, the value of the counter CNT corresponding to the storage number of the crank angle position θf detected by the second crank angle sensor 4 is set to “3”.

  In step S1802, it is determined whether the end of the crank angle position to be processed has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is [P_NUM2-2]. When it is determined in step S1802 that the end of the crank angle position to be processed has not been reached (NO), the process proceeds to step S1803 and the processing is continued, and it is determined that the end of the crank angle position to be processed has been reached (YES) ends the process.

In step S1803, the crank angular acceleration corresponding to the value of the counter CNT indicating the storage number of the CQ cylinder is estimated based on the following equation (28).

  Returning to FIG. 12, the cylinder number CQ is decremented in step S1212. Next, in step S1213, it is determined whether or not the cylinder number CQ has reached [CB-1], and if it is determined that the cylinder number CQ has reached [CB-1] (YES), The estimation of the crank angle position, the crank angular velocity, and the crank angular acceleration from the crank angle sensor 4 toward the non-output side end of the crankshaft 2 is judged to be finished and the processing is finished.

  Returning to the flowchart of FIG. 3, the description of the flow of the process of estimating the pressure in the combustion cylinder will be continued. In FIG. 3, in step S304, using the estimated torque value for each crank angle position of the combustion cylinder calculated by the combustion cylinder torque estimating means 13, the generated torque of the combustion cylinder is estimated.

For example, as described above, if the combustion cylinder is the second cylinder # 2, the parameter θ1 to be substituted into the above equation (6), which is a relational equation for calculating the torque T2 of the combustion cylinder,
, Θ2, and θ3 are directly detected by the first crank angle sensor 3, or the above-described equations (5) to (9) from the two directions from the non-output side end of the crankshaft 2 and the output side end. ) By solving the relational expression in order. Therefore, by substituting these parameter values into the equation (6) for each value of the counter CNT indicating the storage number of the first crank angle position θ1 detected by the first crank angle sensor 3, for each value of the counter CNT, The combustion cylinder torque T2 can be obtained.

  Next, the flow of processing for estimating the combustion cylinder torque in the combustion cylinder torque estimating means 13 will be described. FIG. 19 is a flowchart showing a flow of processing for estimating the torque of the combustion cylinder in the control apparatus for an internal combustion engine according to the first embodiment of the present invention. In FIG. 19, first, an equation for calculating the torque of the combustion cylinder is selected in step S1901. Formulas for calculating the torque of the combustion cylinder are prepared in advance as shown in the above formulas (5) to (9). Based on the combustion cylinder CB obtained from the combustion cylinder discriminating means 11, a formula for calculating the combustion torque is selected from the following calculation formula group. Here, in the case of [CB = 1], the following equation (29) is selected, in the case of [CB = m], the following equation (30) is selected, and in the other cases, the following equation (31) is selected.

  Next, “3” is set in the counter CNT indicating the storage number of the first crank angle position θ1 detected by the first crank angle sensor 3 in step S1902. In step S1903, it is determined whether the end of the crank angle position to be processed has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is [P_NUM1-2]. As a result of the determination in step S1903, if it is determined that the counter value has not reached the end of the crank angle position to be processed (NO), the process proceeds to step S1904 and the processing is continued to reach the end of the crank angle position to be processed. If it is determined that the process has been completed (YES), the process ends.

In step S1904, except for the case where the combustion cylinder CB is [CB = 1], the crank angle position θ _CB and the crank angular acceleration of the combustion cylinder.
Is estimated from both the first crank angle sensor 3 and the second crank angle sensor 4. In the first embodiment, a value estimated based on the output from the first crank angle sensor 3 is used. In step S1905, the counter CNT is incremented, and the process returns to step S1903.

  Returning to FIG. 3, the description will be continued. In FIG. 3, in step S305, the in-cylinder pressure of the combustion cylinder is estimated using the estimated torque calculated by the combustion cylinder torque estimating means 13. FIG. 20 is an explanatory diagram showing the dynamic relationship of the piston / crank system in the control apparatus for an internal combustion engine according to the first embodiment of the present invention, showing the relationship between the force acting on the crankshaft from the piston. ing. In FIG. 20, Pcyl is the cylinder pressure, F is the force applied from the piston to the crankshaft, θ is the crankshaft displacement angle from the top dead center TDC of the piston, r is the crankshaft radius, and λr is the length of the connecting rod. It shows. Here, when the torque received by the crankshaft from the piston is T, T is expressed by the following equation (32).

If the force due to the combustion gas is Fg and the force due to the inertial force of the piston is Fi (i is the cylinder number), the force F applied from the piston to the crankshaft is expressed by the following equation (33).

Here, when the area of the upper surface of the piston is S, the force Fg caused by the combustion gas is represented by [Fg = Pcyl · S], and the force Fi caused by the piston inertia force is represented by the following equation (34).

Mp is the reciprocating mass of the piston. Therefore, the in-cylinder pressure Pcyl to be estimated is obtained by the following equation (35) from the above equations (32) to (34).

  Next, the process flow of the combustion cylinder pressure estimating means 14 will be described. FIG. 21 is a flowchart showing the flow of processing for estimating the pressure in the combustion cylinder in the control device for the internal combustion engine according to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment of the present invention. It is. In FIG. 21, first, in step S <b> 2101, “3” is set in the counter CNT indicating the storage number of the first crank angle position θ <b> 1 detected by the first crank angle sensor 3. Next, in step S2102, it is determined whether or not the end of the crank angle position to be processed has been reached. Here, the storage number of the crank angle position corresponding to the end of the process is [P_NUM1-2].

As a result of the determination in step S2102, if it is determined that the end of the crank angle position to be processed has not been reached (NO), the process proceeds to step S2103 and the processing is continued, and the end of the crank angle position to be processed has been reached. If it is determined (YES), the process is terminated. By the processing in step S2103, the combustion cylinder torque TCB (CNT) estimated by the combustion cylinder torque estimation means 13, the crank angle position θ (CNT) of the combustion cylinder estimated by the crank angle information estimation means 10, and the crank angular velocity
Is substituted into (Equation 35) to calculate the in-cylinder pressure Pcyl (CNT). In step S2104, the counter CNT is incremented, and the process returns to step S2102. Here, (CNT) means that it corresponds to the value of the counter CNT indicating the storage number of the crank angle position to be processed.

  As described above, according to the control apparatus for an internal combustion engine according to the first embodiment, the torsional vibration is caused in the crankshaft 2 by the two crank angle sensors provided at the non-output side end and the output side end of the crankshaft 2. Even in the case where the above occurs, the crank angle position, crank angular velocity, and crank angular acceleration of each cylinder can be estimated. For this reason, the cylinder pressure of the combustion cylinder can be accurately estimated.

Embodiment 2. FIG.
Next, a description will be given of an internal combustion engine control apparatus according to Embodiment 2 of the present invention. In the control apparatus for an internal combustion engine according to the first embodiment described above, except for the case where the combustion cylinder is the first cylinder, the crank angle position of the combustion cylinder is the first crank angle sensor 3 and the second crank angle. It could be obtained from both sensors 4. For example, in the control apparatus for an internal combustion engine according to the first embodiment, when the combustion cylinder is the second cylinder # 2, the crank angle position of the second cylinder # 2 has two types of θ2e1 and θ2ef as described above. Shown that it is required.

  However, since the crank angle position of each cylinder is estimated by obtaining a numerical solution of a second order differential using, for example, the center difference method, a minute error may be included. Therefore, when estimating the crank angle position in the direction away from the measurement position by the crank angle sensor, this minute error is accumulated, and the value detected by the crank angle sensor located far from the combustion cylinder is calculated. If the crank angle position of the combustion cylinder is estimated based on this, the estimation accuracy may decrease. As a result, the accuracy of the estimated value of the in-cylinder pressure of the combustion cylinder is lowered.

  The control apparatus for an internal combustion engine according to the second embodiment solves the above-described problems in the control apparatus for the internal combustion engine according to the first embodiment. Hereinafter, the control apparatus for an internal combustion engine according to the second embodiment will be described. The internal combustion engine, the crank angular acceleration calculation process, the crank angle information estimation process, and the combustion cylinder pressure estimation process are respectively shown in FIG. 1, FIG. 3, and FIG. 6, FIG. 12 and FIG. 21 are the same as those in FIG.

  FIG. 22 is a block diagram showing a basic conceptual configuration of estimation of the in-cylinder pressure in the control apparatus for an internal combustion engine according to the second embodiment of the present invention. In the control apparatus for an internal combustion engine according to the second embodiment, the configuration of the combustion cylinder torque estimating means 13 of FIG. 2 in the case of the control apparatus for an internal combustion engine according to the first embodiment is changed. In FIG. 22, the combustion cylinder torque estimating means 13 has a crank angle information selecting means 15 for selecting the crank angle position and the crank angle acceleration of the combustion cylinder calculated by the crank angle information estimating means 10.

  FIG. 23 is a flowchart showing the flow of processing for estimating the combustion cylinder torque in the control apparatus for an internal combustion engine according to the second embodiment of the present invention and the third embodiment to be described later. The content of the process of the estimation means 13 is shown, and a part of the content of the process of FIG. 19 in the case of Embodiment 1 is changed. Specifically, in the flowchart of FIG. 23 according to the second embodiment, the process of step S2301 is added between step S1901 and step S1902 of FIG. 19 according to the first embodiment.

  That is, in FIG. 23, in step S2301, the crank angle position and crank angle of the combustion cylinder sequentially obtained based on the detection signal from the crank angle sensor closer to the combustion cylinder CB obtained by the combustion cylinder discrimination means 11 The acceleration is selected by the crank angle information selection means 15. Then, the selected crank angle position and crank angular acceleration are used to calculate the combustion cylinder torque TCB (CNT) in step S1904.

  As described above, according to the control apparatus for an internal combustion engine according to the second embodiment, the same effects as those of the first embodiment can be obtained, and the crank angle position of the combustion cylinder sequentially obtained from the crank angle sensor close to the combustion cylinder. Since the crank angular acceleration is used for estimating the combustion cylinder torque, errors in the crank angle position and crank angular acceleration of the combustion cylinder can be reduced. For this reason, the estimated value of the cylinder pressure of the combustion cylinder with higher accuracy can be obtained.

Embodiment 3 FIG.
Next, a description will be given of an internal combustion engine control apparatus according to Embodiment 3 of the present invention. In the first embodiment, the crank angle position of the combustion cylinder is obtained from both the first crank angle sensor 3 and the second crank angle sensor 4 except when the combustion cylinder is the first cylinder. It was shown that you can. However, since the crank angle position of each cylinder is estimated by obtaining a numerical solution of the second order differential using, for example, the center difference method, a minute error may be included.

  Specifically, this error increases when the angular interval of the crank angle position detected with respect to the speed of change in the rotational speed of the crankshaft 2 is large. That is, the error is larger when the number of protrusions of the signal rotor of the crank angle sensor is smaller than when the number of protrusions is large. Therefore, if the crank angle position of the combustion cylinder is estimated based on the value detected by the crank angle sensor with the smaller number of protrusions of the signal rotor, the estimation accuracy may decrease. As a result, the accuracy of the estimated value of the in-cylinder pressure of the combustion cylinder is lowered.

  An internal combustion engine control apparatus according to Embodiment 3 of the present invention solves the above-described problems. FIG. 23 is a block diagram showing a basic conceptual configuration of an in-cylinder pressure estimation processing unit in the control apparatus for an internal combustion engine according to the second and third embodiments of the present invention. The basic process of the internal combustion engine and the cylinder pressure estimation processing unit, the crank angle acceleration calculation process, the crank angle information estimation process, and the combustion cylinder pressure estimation process are respectively shown in FIG. 1 and FIG. 1 described in the first embodiment. 3, FIG. 12, FIG. 21 and FIG. 21 are the same, and FIG. 22 in the second embodiment is also the same, so detailed description thereof will be omitted.

  Further, the basic flow of the combustion cylinder torque estimation process in the third embodiment is the same as the basic flow of FIG. 23 in the third embodiment, but in the third embodiment, the process of step S2301 in FIG. Only the contents are different from those in the third embodiment. That is, in FIG. 23, when the number of protrusions of the first signal rotor 22 and the second signal rotor 23 shown in FIG. 1 is different, step S2301 is the crank corresponding to the signal rotor having the larger number of protrusions. Based on the output from the angle sensor, the angular position and angular acceleration of the combustion cylinder obtained sequentially are selected.

  If the number of protrusions of the first signal rotor 22 and the second signal rotor 23 is the same, the crank angle position of the combustion cylinder and the crank angular acceleration obtained sequentially based on the output of one of the crank angle sensors. Select. The crank angle position and the crank angular acceleration are used for calculating the combustion cylinder torque TCB (CNT) in step S1904.

  As described above, according to the control apparatus for an internal combustion engine according to the third embodiment, the same effect as in the first embodiment can be obtained, and the protrusions of the first signal rotor 22 and the second signal rotor 23 can be obtained. When the number of objects is different, the crank angle position of the combustion cylinder and the crank angle acceleration obtained sequentially based on the output of the crank angle sensor with the larger number of protrusions of the signal rotor are used to estimate the combustion cylinder torque. Errors in the crank angle position and crank angle acceleration of the cylinder can be reduced. For this reason, the estimated value of the cylinder pressure of the combustion cylinder with higher accuracy can be obtained.

Embodiment 4 FIG.
Next, a description will be given of an internal combustion engine control apparatus according to Embodiment 4 of the present invention. In the control apparatus for an internal combustion engine according to the first embodiment, the crank angle position of the combustion cylinder is determined by both the first crank angle sensor 3 and the second crank angle sensor 4 except when the combustion cylinder is the first cylinder. In the second and third embodiments, only the crank angle position of the combustion cylinder based on the output from one of the first crank angle sensor 3 and the second crank angle sensor 4 is used. Thus, the in-cylinder pressure of the combustion cylinder is estimated. However, if an error occurs when assembling one of the crank angle sensors and the corresponding signal rotor, or if noise is superimposed on the output signal of the crank angle sensor, only the value detected by the crank angle sensor affected by these will be used. If the crank angle position of the combustion cylinder is estimated based on this, the estimation accuracy may be lowered, and consequently, the accuracy of the estimated value of the in-cylinder pressure of the combustion cylinder is lowered.

  The control apparatus for an internal combustion engine according to the fourth embodiment solves the above-described problems. Hereinafter, the control apparatus for the internal combustion engine according to the fourth embodiment will be described. The internal combustion engine, crank angular acceleration calculation processing, crank angle information estimation processing, and combustion cylinder pressure estimation processing are the same as those shown in FIGS. 1, 3, 6, 12, and 21 described in the first embodiment. Since they are the same, detailed description is omitted.

  FIG. 24 is a block diagram showing a basic conceptual configuration of an in-cylinder pressure estimation processing unit in the control apparatus for an internal combustion engine according to the fourth embodiment of the present invention. In FIG. 24, the structure of the combustion cylinder torque estimation means 13 of FIG. 2 of Embodiment 1 is changed. That is, in FIG. 24, the combustion cylinder torque estimating means 13 has a crank angle information correcting means 16, and the crank angle positions and crank angles of the two types of combustion cylinders calculated by the crank angle information estimating means 10. Using both of the accelerations, the crank angle position and crank angle acceleration of the combustion cylinder used to estimate the torque of the combustion cylinder are calculated.

  FIG. 25 is a flowchart showing the flow of processing for estimating the torque of the combustion cylinder in the control apparatus for an internal combustion engine according to Embodiment 4 of the present invention, and shows the contents of the processing of the combustion cylinder torque estimating means 13. ing. In FIG. 25, the processing content of step S2301 of FIG. 23 described in the second and third embodiments is changed to step S2501. In FIG. 25, in step S2501, the crank angle position and crank angular acceleration of the combustion cylinder are calculated using output signals from both the first crank angle sensor 3 and the second crank angle sensor 4. Specifically, the torque TCB (CNT) of the combustion cylinder is calculated in step S1904 using the crank angle position and crank angular acceleration calculated by the following equations (36) and (37).

here,
Are the crank angle position and the crank angular acceleration calculated based on the output signal of the first crank angle sensor 3, respectively.
Are the crank angle position and the crank angular acceleration calculated based on the output signal of the second crank angle sensor 4, respectively. or,
Is the adjustment factor,
Take a range of.

Adjustment factor
Is the crank angle position of the combustion cylinder and the crank angular acceleration obtained sequentially from the crank angle sensor closer to the combustion cylinder CB obtained by the combustion cylinder discriminating means 11 in the above-described equations (36) and (37). Set so that the contribution is large. For example, if the combustion cylinder is closer to the first crank angle sensor 3 than the second crank angle sensor 4,
By setting within this range, an accurate crank angle position and crank angle acceleration can be obtained. still,
May be variably set according to the distance between the two crank angle sensors.

Another setting method is the adjustment factor.
When the difference in the number of protrusions between the first signal rotor 22 for the first crank angle sensor 3 and the second signal rotor 23 for the second crank angle sensor 4 is large, the expression (36) and the expression In the calculation of the crank angle position and the crank angle acceleration shown in (37), the degree of contribution with the larger number of protrusions is set to be larger. For example, when the number of protrusions of the first signal rotor 22 for the first crank angle sensor 3 is larger than the number of protrusions of the second signal rotor 23 for the second crank angle sensor 4,
By setting within this range, an accurate crank angle position and crank angle acceleration can be obtained.

  As described above, according to the control apparatus for an internal combustion engine according to the fourth embodiment of the present invention, the same effect as in the first embodiment can be obtained, and further, the first crank angle sensor 3 and the second crank Since both the angle sensor 4 is used to calculate the crank angle position and crank angle acceleration of the combustion cylinder, even if one crank angle sensor has a large output error, the influence of the output of the other sensor is suppressed. Therefore, the errors in the crank angle position and crank angle acceleration of the combustion cylinder can be reduced. For this reason, the estimated value of the cylinder pressure of the combustion cylinder with higher accuracy can be obtained.

  Although the first to fourth embodiments of the present invention have been described above, the present invention can be freely combined with each other within the scope of the present invention, or each embodiment can be modified as appropriate. It can be omitted. For example, in order to obtain a numerical solution of the relational expression group of the elastic body model, the angular velocity and the angular acceleration are calculated using the difference method, but this may be obtained using a Fourier transform.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine, 2 Crank shaft, 3 1st crank angle sensor, 4 2nd crank angle sensor, 5 Cam shaft, 6 Cam angle sensor, 7 Control apparatus, 7A Combustion cylinder pressure estimation process part, 8 Crank angle signal Input time storage means, 9 crank angular acceleration calculation means, 10 crank angle information estimation means, 11 combustion cylinder discrimination means, 12 non-combustion cylinder torque setting means, 13 combustion cylinder torque estimation means, 14 combustion cylinder pressure estimation means, 15 crank Angle information selection means, 16 crank angle information correction means, 20 piston, 22 first signal rotor, 23 second signal rotor, 25 third signal rotor.

Claims (6)

A control device for an internal combustion engine comprising a plurality of cylinders having pistons coupled to a crankshaft,
A first crank for detecting a crank angle position at a different position in the axial direction of the crankshaft by sandwiching one or more of the cylinders to be estimated for a combustion state in the axial direction of the crankshaft An angle sensor and a second crank angle sensor;
A first crank angle position inputted from the first crank angle sensor, a time when the first crank angle position is inputted, and a second crank angle position inputted from the second crank angle sensor; Crank angle signal input time storage means for storing the time at which the second crank angle position is input;
Based on the time data stored in the crank angle signal input time storage means, a first crank angular acceleration corresponding to the first crank angle position and a second crank corresponding to the second crank angle position. Crank angular acceleration calculating means for calculating angular acceleration;
Based on the first crank angle position, the first crank angular acceleration, the second crank angle position, and the second crank angular acceleration, the crank angle positions and crank angular accelerations of the plurality of cylinders are estimated. Crank angle information estimating means for performing,
A cam angle sensor for detecting a cam angle of a camshaft connected to the crankshaft;
Combustion cylinder determining means for determining a combustion cylinder in a combustion state among the plurality of cylinders based on a cam angle signal from the cam angle sensor;
Non-combustion cylinder torque setting means for setting an estimated torque of a cylinder other than the combustion cylinder;
Combustion cylinder torque estimating means for estimating torque of the combustion cylinder based on crank angle positions and crank angular accelerations of the plurality of cylinders estimated by the crank angle information estimating means;
Combustion cylinder pressure estimation means for estimating the cylinder pressure of the combustion cylinder based on the torque estimated by the combustion cylinder torque estimation means;
A control apparatus for an internal combustion engine, comprising: The combustion cylinder torque estimating means includes crank angle information selecting means,
The crank angle information selection means includes
As information related to the crank angle position used when estimating the torque of the combustion cylinder, a position close to the combustion cylinder in the axial direction among the first crank angle sensor and the second crank angle sensor. Selecting information related to the crank angle position detected by an existing crank angle sensor;
The control apparatus for an internal combustion engine according to claim 1. The combustion cylinder torque estimating means includes crank angle information selecting means,
The crank angle information selection means includes
As information related to the crank angle position used when estimating the torque of the combustion cylinder, the number of signals generated in one rotation of the internal combustion engine among the first crank angle sensor and the second crank angle sensor is as follows. Select the relevant information of the crank angle detected by the more crank angle sensor,
The control apparatus for an internal combustion engine according to claim 1. The combustion cylinder torque estimating means includes crank angle information correcting means,
The crank angle information correcting means includes
Related to the crank angle position used when estimating the torque of the combustion cylinder using a weighted average of information related to the crank angle position detected by each of the first crank angle sensor and the second crank angle sensor. Correct information
The control apparatus for an internal combustion engine according to claim 1. The crank angle information correcting means includes
A weighted average weight used for the correction is determined based on a distance in the axial direction of the combustion cylinder with respect to the first crank angle sensor or the second crank angle sensor.
The control apparatus for an internal combustion engine according to claim 4. The crank angle information correcting means includes
A weighted average weight used for the correction is determined based on the number of signals generated in one rotation of the internal combustion engine;
The control apparatus for an internal combustion engine according to claim 4.