JP2004218470A - Control equipment and control cylinder grouping method of internal-combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide output torque control equipment for improving driveability while keeping a fuel consumption to a minimum in control equipment of an internal-combustion engine with a plurality of cylinders. <P>SOLUTION: There is provided the internal-combustion engine control equipment equipped with a regulating means for regulating combustion of each cylinder so that a vibration cycle of output torque generated according to a combustion order of the plurality of the cylinders becomes shorter than that of the output torque whose one cycle is defined by a time required for all the cylinders to accomplish combustion. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method and control apparatus for an internal combustion engine having a plurality of cylinders, and more particularly to control of torque of each cylinder.
[0002]
[Prior art]
In a multi-cylinder internal combustion engine, there is a difference in the intake air amount for each cylinder due to variations in the operating angle of the cam that drives the intake and exhaust valves, the valve lift amount, the profile, and the like. Due to the difference in the intake air amount for each cylinder, a difference in output torque occurs between the cylinders, and vibration due to uneven output torque may deteriorate drivability. Conventionally, in order to eliminate this non-uniformity of torque between cylinders, a technique for detecting the combustion pressure from the deviation of the number of revolutions for each cylinder and controlling the fuel injection amount and the ignition timing so that the combustion pressure for each cylinder becomes uniform. It has been known. In this technique, by correcting the control parameters of the internal combustion engine such as the fuel injection amount and the ignition timing, the cylinder with a high detected torque decreases the torque, and the cylinder with a low detected torque increases the torque to increase the actual torque for each cylinder. Is controlled to be uniform. As a document showing such a control device for a multi-cylinder internal combustion engine, there is Patent Document 1 below.
[Patent Document 1]
Japanese Patent Publication No. 7-37789
[Patent Document 2]
JP 2001-263015 A
[0003]
[Problems to be solved by the invention]
However, with the technology that equalizes the actual torque of each cylinder, in reality, the actual torque of each cylinder is uniformly controlled to a lower torque, and drivability is improved, but fuel consumption and emissions are deteriorated. It was a problem. In practice, the control parameters of the internal combustion engine are set to optimum values in consideration of output, fuel consumption, and emissions, and it is difficult to improve the combustion state of the cylinders with the control parameters and increase the output torque. On the other hand, the reduction control of the output torque is a control that deteriorates the combustion state and can be performed relatively easily.
[0004]
Recently, a vehicle equipped with a variable valve mechanism that can vary the operating angle and lift amount of an intake valve and an exhaust valve according to the operation state of the internal combustion engine has been proposed. In this variable valve mechanism, an intermediary drive mechanism is interposed between the rotary cam that is linked to the crankshaft and the rocker arm that transmits the cam movement to the intake valve, and the input portion of the intermediary drive mechanism that contacts the rotary cam contacts the rocker arm. The lift amount of the intake valve is continuously adjusted by variably controlling the phase difference with the output portion of the intermediate drive mechanism. In such a variable valve mechanism, since the number of components increases, it is difficult to make the valve open state the same among the cylinders. As a result, it has been difficult to make the intake air amount uniform among the cylinders. In an internal combustion engine having such a variable valve mechanism, conflicting performance improvements such as improved drivability and improved fuel economy and emission countermeasures are further desired.
[0005]
An object of the present invention is to solve these problems and to control the torque of each cylinder while minimizing deterioration of fuel consumption and emission, and to improve drivability.
[0006]
[Means for solving the problems and their functions and effects]
In order to solve at least a part of the above problems, the present invention has taken the following technique. In other words, the control apparatus for an internal combustion engine having four or more cylinders, wherein the output torque oscillation period generated in accordance with the combustion order of the cylinders is an output in which the time until completion of combustion for all cylinders is one period. The gist is that an adjusting means for adjusting the combustion state of each cylinder in the previous period is provided so that the cycle is shorter than the vibration of the torque.
[0007]
According to the first control apparatus for an internal combustion engine of the present invention, the output torque vibration period generated in accordance with the combustion order of the plurality of cylinders is the output torque vibration having a period until the completion of combustion for all the cylinders as one period. Shorter than the period. Therefore, it is possible to increase the frequency so that the driver can hardly detect the vibration of the output torque, which is effective in improving drivability. Further, in order to improve the drivability by using the vibration of the output torque as a high frequency, it is not necessary to perform a torque reduction control that uniformly matches the output torque of all the cylinders. Therefore, deterioration in fuel consumption can be minimized.
[0008]
Such a control device for an internal combustion engine does not continue the torque detection means for detecting the output torque for each of the plurality of cylinders of the internal combustion engine at a predetermined timing as the adjustment means, and the plurality of cylinders in the combustion order. Targets given to each cylinder included in the cylinder group so that the actual torque is the same for each cylinder group and different between the cylinder groups for a plurality of cylinder groups that are grouped including at least one cylinder. A target torque applying means for applying torque can be provided. That is, grasp the value of the detected torque for each cylinder detected by the torque detection means, and adjust the target torque for each cylinder so that each cylinder group has the same actual torque based on the detected value can do.
[0009]
Further, the target torque applying means is a predetermined torque between a maximum detected torque and a minimum detected torque among the detected torques for each cylinder detected by the torque detecting means. As described above, the target torque of the cylinders included in the cylinder group can be adjusted. Since it is based on the detected torque of the torque detection means, the cylinder showing the maximum detected torque and the cylinder showing the lowest detected torque can be easily determined, and the predetermined torque can be set between the two torques. Therefore, it is only necessary to execute torque reduction control that lowers the output torque for cylinders with large detected torque, and torque increase control that increases the output torque for cylinders with small detected torque, and the adjustment of the target torque for each cylinder is clear and easy. It becomes.
[0010]
The predetermined timing may be when the vehicle is idling. When the internal combustion engine rotates at a high speed, drivability is not a problem, but it is regarded as important when idling. At the time of idling, the target torque for each cylinder is adjusted from the torque detected by the torque detecting means to control the combustion state, which is effective in improving drivability.
[0011]
Further, the torque detecting means may be a means for detecting based on at least one of estimation based on detection of rotational fluctuation of the internal combustion engine, estimation based on detection of combustion time, and detection of in-cylinder pressure. The detection means described above can be detected by a relatively simple combination of sensors, and can be handled with existing devices and slight improvements.
[0012]
Further, the target torque applying means is configured such that the actual torque of the cylinder group including the cylinder that is the lowest detected torque among the detected torques detected by the torque detecting means is greater than the actual torque of the other cylinder groups. It can be a means for adjusting the target torque of the cylinders included in the cylinder group so as to obtain a low predetermined torque. Usually, the target torque is set so that the output torque of each cylinder is optimized. Therefore, it is difficult to perform torque increase control that further optimizes the combustion state of the cylinder. On the other hand, it is easy to perform torque reduction control that deteriorates the combustion state of the cylinder. The cylinder group including the cylinder having the lowest torque from the torque detection result is set to have a lower actual torque than the other cylinder groups, and the target torque of each cylinder in the cylinder group is adjusted.
[0013]
Further, if the internal combustion engine has four or more cylinders, the number of cylinders such as five cylinders, six cylinders, eight cylinders, and twelve cylinders is not limited. For example, in an internal combustion engine having four cylinders, one of the grouped cylinder groups is one. When the cylinders in the expansion stroke are in the expansion stroke, the remaining cylinders can be in the intake stroke. That is, in an internal combustion engine having four cylinders, every other cylinder in the combustion order is set to the same cylinder group, and the target torque for each cylinder is set so that each cylinder group has different actual torque among the cylinder groups. adjust. By this control, actual torques that appear alternately in the order of combustion appear, and the actual torque alternately repeats the magnitude relationship of the torque. Therefore, in an internal combustion engine having four cylinders, the period of torque vibration can be made particularly short, the frequency can be increased, and drivability can be improved.
[0014]
Furthermore, among the internal combustion engines in which the intake valve opens and closes with the rotation of the crankshaft, the intake valve is interposed between the rotation of the crankshaft of the internal combustion engine and the intake valve that opens and closes accordingly. The internal combustion engine can be provided with a variable valve mechanism that changes the pressure. In an internal combustion engine having such a mechanism, output torque between cylinders is likely to vary, and the effect of performing control of the internal combustion engine is great.
[0015]
The adjusting means may comprise means for controlling the detected torque for each cylinder based on at least one of air-fuel ratio control and ignition timing control of the internal combustion engine. An existing sensor can be adopted by controlling the increase / decrease of torque as air / fuel ratio control and ignition timing control, and it can be performed relatively easily by improving existing control means. .
[0016]
Further, the target torque applying means is the actual torque of the cylinder group including the cylinder that is the maximum detected torque among the detected torques for each cylinder detected by the torque detecting means, and the actual torque and the lowest detected torque. The target torque of the cylinders included in the cylinder group may be adjusted so that the difference from the actual torque of the cylinder group including the cylinder is within a predetermined value. Improvement in drivability can be achieved by setting the frequency of vibration of the output torque to a high frequency, but can also be achieved by suppressing the amplitude of torque vibration to a predetermined amount. The actual torque of the cylinder group including the cylinder with the maximum detected torque is determined so that the difference between the actual torque and the actual torque of the cylinder group including the cylinder with the lowest detected torque is within a predetermined value, that is, the maximum detection The target torque for each cylinder of the cylinder group including the cylinder that is the maximum detected torque is adjusted so that the actual torque of the cylinder group that includes the cylinder that is the torque is reduced. Therefore, the amplitude of the output torque can also be suppressed, and the drivability is further improved.
[0017]
Further, the target torque applying means is included in the cylinder group when the detected torque of the cylinder that is the lowest detected torque among the detected torques for each cylinder detected by the torque detecting means is a predetermined torque. It is also possible to use means for prohibiting adjustment of the target torque of the cylinder that increases the detected torque. If the detected torque of the cylinder determined to be the lowest detected torque from the torque detection result is a predetermined torque (for example, an optimum torque), adjusting the target torque to increase the cylinder torque is not possible. Especially difficult. In this case, the adjustment of the target torque for each cylinder in the cylinder group including the cylinder showing the lowest detected torque is prohibited from being torque increase control. Therefore, unnecessary control is not performed.
[0018]
In addition, a grouping method for classifying a plurality of cylinders in order to select a cylinder that should have the same actual torque by performing torque control among the plurality of cylinders, divides four or more cylinders into two or more cylinder groups, A grouping method for dividing the plurality of cylinders into at least two groups in order to control the actual torque that is the same for each cylinder group and different between the cylinder groups, wherein the four or more cylinders are defined as n cylinders (n Is an integer greater than or equal to 4), among the cylinders exhibiting a large output torque in the n cylinders, when the number of consecutive cylinders R (R is an integer greater than or equal to 3) is n-1 or less, A control cylinder grouping method may be used in which the remaining cylinders excluding the cylinders at both ends of the cylinder are grouped so as to include at least one cylinder that is not consecutive in the combustion order.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a schematic configuration of a control system system in which a control device for an internal combustion engine, which is a first embodiment of the present invention, is mounted. Moreover, the schematic diagram of the longitudinal cross-section of one cylinder is shown in FIG. As shown in the figure, the engine 10 is a four-cylinder engine having four cylinders 20a, 20b, 20c, and 20d (hereinafter, referred to as a cylinder 20 when it is not particularly necessary to distinguish the cylinders). The engine 10 mainly includes a cylinder block 30, a piston 40 that reciprocates in the cylinder block 30, a cylinder head 50, an intake valve 60 disposed on the cylinder head 50, an exhaust valve 70, and the like. The intake valve 60 and the exhaust valve 70 are a four-valve system provided with two for each cylinder 20. A combustion chamber 80 surrounded by the cylinder block 30, the cylinder head 50, and the piston 40 is formed in each cylinder 20. The cylinder head 50 is provided with a spark plug 85 and ignites the air-fuel mixture compressed in the combustion chamber 80.
[0020]
Two intake ports 65 provided in each cylinder 20 are connected to the intake manifold 90. Each intake passage 95 is formed in the intake manifold 90 and includes a fuel injection valve 100. The fuel injection valve 100 is opened for a time corresponding to the energization time of the solenoid coil inside, and injects an amount of fuel corresponding to the opening time τ into each cylinder 20. That is, the amount of fuel corresponding to the operating state is supplied to each cylinder 20 by adjusting the energization time. The intake manifold 90 of each cylinder 20 is connected to the intake duct 120 via the surge tank 110. The intake duct 120 is provided with an air flow meter 115 for detecting the intake air amount Q. The intake duct 120 is connected to the air cleaner 130 and takes in air filtered by the air cleaner 130. The air flow meter 115 detects the intake air amount Q for air-fuel ratio control that makes the air-fuel mixture appropriate.
[0021]
Two exhaust ports 75 provided in each cylinder 20 are connected to the exhaust manifold 160. The exhaust manifold 160 is provided with an oxygen concentration sensor 170 to detect the oxygen concentration in the exhaust. That is, it detects whether the oxygen concentration is rich or lean for air-fuel ratio control that makes the air-fuel mixture appropriate. Further, the exhaust manifold 160 is connected to the catalytic converter 175. The catalytic converter 175 purifies the exhaust from each cylinder 20 and discharges it to the outside.
[0022]
The cylinder head 50 is rotatably provided with an intake camshaft 63 and an exhaust camshaft 73 that rotate as the engine 10 rotates. The exhaust cam shaft 73 is provided with an exhaust cam 77 and is in contact with one end of a rocker arm 141 that directly lifts the exhaust valve 70. The exhaust valve 70 is opened and closed through an rocker arm 141 by an exhaust cam 77 that rotates as the engine 10 rotates. On the other hand, the intake camshaft 63 is provided with an intake cam 67 and is in contact with an input portion of an intermediate drive mechanism 200 described later. The output portion of the mediation drive mechanism 200 is in contact with one end of a rocker arm 140 that directly lifts the intake valve. The intake valve 60 is opened and closed through an intermediate drive mechanism 200 and a rocker arm 140 by an intake cam 67 that rotates in association with the rotation of the engine 10.
[0023]
The intake duct 120 of the first embodiment is not provided with a throttle valve. The intake air amount Q required in the combustion chamber 80 is controlled by adjusting the valve lift amount of the intake valve 60 from the engine 10 speed required by the operation of the accelerator pedal or the like. The lift amount of the intake valve 60 is adjusted by an intermediate drive mechanism 200 provided between the intake cam 67 and the rocker arm 140.
[0024]
The mediation drive mechanism 200 is provided in the cylinder head 50 and mainly includes a control shaft 201 provided in parallel with the intake camshaft 63, an input unit 202 engaged with the control shaft 201, and a swing cam 203. ing. The input unit 202 is provided with a roller 205 that contacts the intake cam 67 and is involved in the opening / closing timing of the intake valve 60. Further, the swing cam 203 is formed with a protrusion called a nose 207 that directly contacts the rocker arm 140. Helical splines (not shown) are provided in the axial direction inside the engaging portions of the input portion 202 and the swing cam 203 with the control shaft 201. The helical splines are provided in opposite directions in the input unit 202 and the swing cam 203, respectively. The control shaft 201 is provided with a gear (not shown) corresponding to the helical spline and can move in the axial direction relative to the input unit 202 and the swing cam 203.
[0025]
Furthermore, the cylinder head 50 changes the rotational phase of the lift amount variable actuator 210 for controlling the lift amount of the intake valve 60 and the crankshaft rotation of the engine 10 and the intake cam 67, and the opening / closing timing of the intake valve 60 is changed. A rotational phase difference variable actuator 220 for control is provided. The lift amount variable actuator 210 and the rotational phase difference variable actuator 220 are connected to oil control valves 215 and 225, respectively. The oil control valves 215 and 225 are direction switching valves that switch the direction in which the pressure oil flows with an internal spool, and the switching is performed electrically.
[0026]
The control shaft 201 is hydraulically connected to the lift amount variable actuator 210. When the control shaft 201 is moved in the axial direction by hydraulic control of the oil control valve 215 in response to a command from the ECU 250, which will be described later, via a gear provided on the control shaft 201 and a helical spline formed in opposite directions. The angle θ formed by the input unit 202 and the swing cam 203 changes. That is, the relative position (phase) of the roller 205 that contacts the intake cam 67 and the nose 207 that contacts the rocker arm 140 can be changed according to the amount of movement of the control shaft 201 in the axial direction. Therefore, the lift amount of the intake valve 60 can be achieved by controlling the movement amount of the control shaft 201. For example, when the ECU 250 issues a command to increase the lift amount of the intake valve 60, the oil control valve 215 sends pressure oil to the lift amount variable actuator 210, and the lift amount variable actuator 210 moves the control shaft 201 in the axial direction. Move to. Due to the action of the helical spline, the phase angle θ between the roller 205 of the input unit 202 and the nose 207 of the swing cam 203 increases with the movement amount of the control shaft 201, and the lift amount of the intake valve 60 increases. As a result, the valve opening time of the intake valve 60 becomes longer and the intake air amount Q increases.
[0027]
On the other hand, the opening / closing timing of the intake valve 60 is controlled by changing the rotational phase of the intake camshaft 63 accompanying the rotation of the crankshaft. In response to a command from the ECU 250, pressure oil is sent from the oil control valve 225 to the rotational phase difference actuator 220, and the relative position between a sprocket (not shown) provided at the tip of the intake camshaft 63 and the intake camshaft 63 is changed. The sprocket rotates with the crankshaft, but the rotational positions of the intake camshaft 63 and the intake cam 67 with respect to the sprocket are varied by the rotational phase difference actuator 220. By varying the rotational phase of the intake cam 67 accompanying the rotation of the crankshaft, the timing of opening and closing the intake valve 60 can be advanced or delayed. As a result, the opening / closing timing of the intake valve can be adjusted by the lift amount variable actuator 210 and the rotational phase difference actuator 220.
[0028]
The ECU 250 controls the opening / closing timing of the intake valve 60 described above. The ECU 250 controls the fuel injection amount τ in order to respond to various operation requirements and emissions in addition to the opening / closing timing of the intake valve 60. For this purpose, the ECU 250 is connected to various sensors and actuators. ing. Such sensors and actuators include the following.
[0029]
The accelerator pedal is provided with an accelerator position sensor 172 and outputs a voltage proportional to the accelerator depression amount α. The crank angle sensor 174 detects the rotation angle ζ of the crankshaft and outputs a pulse signal for each predetermined rotation angle. The top dead center sensor 176 outputs a pulse signal β when the piston 40 of the predetermined cylinder 20 reaches the top dead center, and determines the stroke of the cylinders 20a, 20b, 20c, and 20d and the piston. 40 top dead centers are detected. The engine 10 speed NE is calculated from the output pulses of the top dead center sensor 176 and the crank angle sensor 174. The water temperature sensor 182 is provided in the cylinder block 30 of the engine 10 and detects the engine 10 cooling water temperature T. The shaft position sensor 178 detects the axial position of the control shaft 201 of the mediation drive mechanism 200 and outputs a voltage corresponding to the axial displacement φ of the control shaft 201. The cam angle sensor 180 detects the cam angle ψ of the intake cam 67 and outputs a pulse signal corresponding to the rotation of the intake cam shaft 63.
[0030]
The ECU 250 inputs signals from the accelerator position sensor 172, crank angle sensor 174, top dead center sensor 176, water temperature sensor 182, shaft position sensor 178, cam angle sensor 180, oxygen concentration sensor 170, air flow meter 115, and the like. In order to optimize the combustion state in each cylinder 20 based on various vehicle information, the fuel injection valve 100 and the oil control valves 215 and 225 are instructed and controlled. In particular, in the control of the fuel injection amount τ, the injection time is determined based on the intake air amount Q from the air flow meter 115 and the signal ζ from the crank angle sensor 174. For example, whether or not the engine 10 is cooled by the water temperature sensor 182. Then, the fuel concentration control unit 170 corrects the vehicle fuel according to various information such as whether or not the air-fuel ratio is appropriate, and gives a fuel injection command to the fuel injection valve 100. In this embodiment, each cylinder 20 is an independent injection method in which the fuel injection amount τ can be controlled independently.
[0031]
Next, torque control according to the first embodiment of the present invention executed by the ECU 250 will be described. This torque control is a control in which when there is a variation in the output torque of each cylinder 20, the number of cylinders 20 that control to worsen the combustion state is suppressed as little as possible, and the cycle of output torque oscillation due to the combustion sequence is set to a high frequency. Therefore, the current combustion pattern in each cylinder 20 is detected, and the cylinder that should deteriorate the combustion state is selected. A flowchart of this torque control process is shown in FIG. As described above, normally, the combustion state of each cylinder 20 is controlled by applying a predetermined target torque to each cylinder 20 so that the combustion state of each cylinder 20 is in a predetermined reference torque range based on various information of the vehicle, an accelerator request, and the like. The ECU 250 detects the output torque of each cylinder 20 output as a result of this control during the idling operation (step S300). In this embodiment, the detection of the output torque of each cylinder 20 is estimated by detecting the engine 10 rotational fluctuation ΔNE of each cylinder 20 per unit time using the crank angle sensor 174 and the top dead center sensor 176. Yes.
[0032]
Generally, if the average pressure in each cylinder 20 that directly affects the output torque of the engine 10 varies in each cylinder 20, the rotation of the engine 10 in each cylinder 20 varies due to the pressure variation. Therefore, the output torque of each cylinder 20 can be estimated by detecting the engine 10 rotational fluctuation ΔNE of each cylinder 20. In addition to the present embodiment, the output torque is estimated by detecting the combustion time of each cylinder 20, and a pressure sensor with good responsiveness is arranged in each cylinder 20 to determine the in-cylinder pressure of each cylinder 20. The output torque may be detected by measuring. Further, when using an existing sensor, the output torque is estimated using the cylinder 20 determination from the crank angle sensor 174 and the cam angle sensor 180 and the air-fuel ratio state signal from the oxygen concentration sensor 170. You can also. In general, in an air-fuel mixture rich in oxygen concentration, the torque output from the combustion cylinder is higher than the torque of the lean air-fuel mixture cylinder. For example, the combustion state of the cylinder 20 at a predetermined time is rich. In this case, the output torque of each cylinder 20 can be estimated by determining which cylinder 20 the rich state is from and roughly estimating the output torque from the air-fuel ratio. Therefore, it is good also as a structure which estimates output torque by these methods.
[0033]
After detecting the torques of the four cylinders 20, it is determined whether or not torque control processing should be executed (step S305). The predetermined reference torque is a design value determined by various conditions such as output, fuel consumption, and emission, and has a certain torque range. If the torques detected for the four cylinders all fall within the predetermined torque range, it is determined that it is not necessary to perform the drivability improvement process, and the process shown in FIG. 3 ends. On the other hand, when the detected torque does not fall within the predetermined torque width and there is a cylinder 20 that shows a value greatly deviating, processing for determining the magnitude of the torque is performed (step S307). In this process, for example, the upper limit value of the torque width is set as the reference torque, and when the detected torque of each cylinder 20 is larger than the reference torque, it is determined that the torque is large, and when the detected torque is small, it is determined that the torque is small. It is processing to do.
[0034]
Subsequently, a process of determining the number of small torque cylinders from the magnitude relationship of each cylinder 20 is performed (step S310). Here, typical patterns of the detected torque of each cylinder 20 are shown in FIGS. The horizontal axis indicates the combustion order of the cylinders, the vertical axis indicates the torque value, the detected torque of each cylinder 20 before execution of the main control is indicated by a white circle, and the actual torque after control is indicated by a black circle. As shown in FIG. 4, combustion in the case of four cylinders is generally performed in the order of the first cylinder 20a, the third cylinder 20c, the fourth cylinder 20d, and the second cylinder 20b. If it is determined in step S310 that the number of small torque cylinders is one, the torque of each cylinder 20 is in the state of the representative pattern A shown in FIG. In the case of pattern A, the first cylinder 20a, the third cylinder 20c, and the fourth cylinder 20d have a large detected torque, and only the second cylinder 20b has a small detected torque. From this detection result, the second cylinder 20b, which is a small torque cylinder, and the third cylinder 20c, which is a cylinder that is not continuous in the combustion order, are set as one group (hereinafter referred to as group G1). Further, the first cylinder 20a and the fourth cylinder 20d, which are large torque cylinders, are set as the other group (hereinafter referred to as a group G2). The predetermined torque T1 and the torque T2 are set so that the actual torque of the group G1 becomes the predetermined torque T1 shown in FIG. 4 and the actual torque of the group G2 becomes the predetermined torque T2. As the predetermined torque T1, a predetermined torque lower than the torque T2 is set.
[0035]
The target torque is not adjusted for the first cylinder 20a and the fourth cylinder 20d, which are large torque cylinder groups such as the group G2. On the other hand, in the group G1, control parameters such as the air-fuel ratio and the ignition timing are already set to optimum values. Therefore, even if the target torque is adjusted by changing this, the detected torque of the small torque cylinder is changed to the large torque cylinder. It is difficult to increase the detected torque (for example, the predetermined torque T2 shown in FIG. 4), and its effect is low. Accordingly, the torque T1 is set as a predetermined torque that slightly increases the detected torque of the second cylinder 20b. The predetermined torque T1 is set in advance as a design value in this embodiment, but may be obtained from detected torque or the like.
[0036]
Next, the process proceeds to a process of adjusting the target torque of each cylinder of the group G1 (step S320 and subsequent steps), and a process of adjusting the target torque applied to each of the second cylinder 20b and the third cylinder 20c of the pattern A is performed. In the pattern A, since the detected torque of the third cylinder 20c is larger than the torque T1, an instruction to perform torque reduction control is issued to the fuel injection valve 100 (step S320). In this case, this is dealt with by reducing the fuel injection amount for realizing the target torque set in the third cylinder 20c before the execution of the torque control and making the air-fuel ratio thin (lean).
[0037]
In general, there is a relationship shown in FIG. 6 between the air-fuel ratio (A / F) and the torque. As shown in the figure, the horizontal axis represents the difference with respect to the theoretical air-fuel ratio, and the vertical axis represents the torque value. The center of the horizontal axis indicates the stoichiometric air-fuel ratio, the right direction from the horizontal axis center is in a lean state, and the left direction is in a rich state. Within a certain air-fuel ratio range, the torque rapidly decreases when the air-fuel ratio is made lean (referred to as leaning), and the torque increases when the air-fuel ratio is made rich (referred to as riching). Even if the intake cam operating angle is controlled in the same manner for a plurality of cylinders, the intake air amount slightly varies. This variation causes a difference in the output torque shown in the figure. In the figure, (a) shows the cylinder torque when the intake air amount is large, (b) shows the case where the intake air amount is in the standard state, and (c) shows the case where the intake air amount is small. Even if there is a difference in torque between the cylinders due to variations in the intake air amount, the torque of each cylinder 20 can be adjusted by controlling the air-fuel ratio within a certain air-fuel ratio range. For example, if two cylinder torques burned at the same operating angle and a certain air-fuel ratio are C point and D point, respectively, the C point of the large torque cylinder can be controlled by making the air-fuel ratio lean and controlling to B point. By making the point D and the air-fuel ratio of the small torque cylinder rich and controlling them to the point A, it is possible to make the torque value substantially the same. However, it is difficult to increase the torque at point D of the small torque cylinder beyond the value of point A. Therefore, in general, variation in output torque between cylinders is adjusted by performing torque reduction control. However, when the air-fuel ratio is within the range where torque can be increased, torque increase control is also performed. Is desirable. Note that the torque reduction control can also be performed by adjusting the ignition timing. Generally, within a certain ignition timing range, the torque increases when the ignition timing is controlled to the advance side, and decreases when the ignition timing is controlled to the retard side. Therefore, in this case, the ignition timing may be controlled to the retard side.
[0038]
Next, in order to control the torque increase of the small torque cylinder, a command for increasing the fuel injection amount and enriching the air-fuel ratio is issued to the fuel injection valve 100 (step S325). As described above, since there is a range in which the torque increase control can be performed by the air-fuel ratio control, the torque increase control is performed with most combustion patterns of the present embodiment. Therefore, in the case of pattern A, the detected torque of the second cylinder 20b is smaller than the torque T1, so an instruction to perform torque increase control is issued to the fuel injection valve 100 (step S325), and the process ends. In this case, the fuel injection amount for realizing the target torque set in the second cylinder 20b is made rich and the air-fuel ratio is made rich. Further, when the ignition timing is used, the control may be performed toward the advance side. As a result, in the pattern A, the magnitude relationship between the actual torques of the cylinders alternately appears in the combustion order as shown by the black circles in FIG.
[0039]
If it is determined in step S310 that the number of small torque cylinders is not one, processing is performed to determine whether the number of small torque cylinders is two (step S330). When it is determined that there are two small torque cylinders, the process proceeds to a process of determining whether the small torque cylinders are continuous (step S340). When it is determined that the small torque cylinders are continuous, the representative pattern B shown by the white circle in FIG. 5 is obtained. In the pattern B, it is difficult to increase the detection torque of the small torque cylinder to the detection torque of the large torque cylinder as described above. Therefore, in this case, the target torque of each cylinder is adjusted so that only the vibration of the output torque is emphasized and the torque of all the cylinders has the same predetermined value ε1.
[0040]
The predetermined value ε1 is set as a design value in this embodiment, but for example, the same torque value as the torque T1 of the pattern A may be used. A command for adjusting the target torque of each cylinder and giving torque reduction control is issued to the fuel injection valve 100 so that the actual torque of the first cylinder 20a and the third cylinder 20c, which are large torque cylinders in the pattern B, becomes a predetermined value ε1. (Step S350) Further, a command for torque increase control is issued to the fuel injection valve 100 so that the actual torque of the fourth cylinder 20d and the second cylinder 20b, which are small torque cylinders, becomes the same predetermined value ε1 (Step S325). ), The process is terminated. As a result, in the pattern B, as shown by the black circles in FIG. 5, the actual torques of all the cylinders have almost the same value, and can be aligned within the same torque width.
[0041]
If it is determined in step S340 that the small torque cylinders do not continue, the representative pattern C shown by the white circle in FIG. 5 is obtained. In pattern C, the magnitude relationship between the detected torques of the cylinders alternately appears in the combustion order before this control is performed. In this case, if the third cylinder 20c and the second cylinder 20b, which are small torque cylinders, are group G11, and the first cylinder 20a and the fourth cylinder 20d, which are large torque cylinders, are group G22, A predetermined torque T22 is set for the group G22, and a predetermined torque T11 lower than the predetermined torque T22 is set for the group G11. The cylinder belonging to the group G22 does not adjust the target torque, and adjusts the target torque of each cylinder of the group G11 so that the actual torque of the cylinder belonging to the group G11 becomes the predetermined torque T11, and performs a command for torque increase control. Is delivered to the fuel injection valve 100 (step S325), and the process is terminated. The predetermined torque T11 is set in the same manner as the torque T1, and the predetermined torque T22 is set in the same manner as the torque T2. As a result, in the pattern C, it is possible to maintain a state in which the magnitude relationship between the actual torques of the cylinders alternately appears in the combustion order.
[0042]
If it is determined in step S330 that the number of small torque cylinders is not two, processing is performed to determine whether the number of small torque cylinders is three (step S360). When it is determined that the number of small torque cylinders is three, a representative pattern D shown by a white circle in FIG. 5 is obtained. In this case, it is the same as pattern B, and the command for torque reduction control is adjusted by adjusting the target torque of the first cylinder 20a, which is the large torque cylinder, so that the actual torque of all the cylinders becomes the same predetermined value ε1. The fuel is injected into the fuel injection valve 100 (step S370). Further, the target torque of the third cylinder 20c, the fourth cylinder 20d, and the second cylinder 20b, which are small torque cylinders, is adjusted, and a command for torque increase control is issued to the fuel injection valve 100 (step S325), and the process is terminated. . As a result, in pattern D, the actual torques of all the cylinders have substantially the same value, and can be aligned within the same torque range.
[0043]
If it is determined in step S360 that the number of small torque cylinders is not 3, processing is performed to determine whether the number of small torque cylinders is 4 (step S380). When it is determined that the number of small torque cylinders is 4, a representative pattern E shown by a white circle in FIG. In this case, the pattern B is the same as that in the pattern B, and the target torque of the small torque cylinders, that is, all the cylinders is adjusted, and a command for torque increase control is issued to the fuel injection valve 100 (step S325), and the process is terminated To do. As a result, in the pattern E, the actual torques of all the cylinders have substantially the same value, and can be aligned within the same torque range. If it is determined in step S380 that all the cylinders are not small torque cylinders, the representative pattern F shown in FIG. 5 is obtained, in which all the cylinders are large torque cylinders. In this case, since the combustion state of each cylinder is good and the vibration of torque is small, the process is terminated without executing the torque control.
[0044]
In the torque control of the first embodiment executed by the ECU 250 as described above, the combustion state of each cylinder is grasped, and the optimal control that balances fuel consumption and drivability is selected. In the case of the patterns A and C shown in FIG. 4 and FIG. 5, the torque control of each cylinder 20 is not performed toward one predetermined torque as in the prior art, but the actual torque of each cylinder 20 is alternated in the combustion order. The control is performed so that the predetermined torque differs. For example, two different predetermined torques are set such that the first cylinder 20a has a large torque, the third cylinder 20c has a small torque, the fourth cylinder 20d has a large torque, and the second cylinder 20b has a small torque. The torque is controlled by adjusting a target torque that has been given to the cylinder in advance or under various conditions of the vehicle. Therefore, the cycle of torque vibration between the cylinders 20 can be shortened to a high frequency, and vibration that is difficult for the driver to detect can be achieved, thereby improving drivability. Moreover, particularly in the torque control of the first embodiment, the torque large cylinder group does not perform the torque reduction control. In other words, the cylinders for which torque reduction control is performed are limited. Since the number of cylinders in which the torque decreases is limited, the deterioration of fuel consumption can be minimized, and the fuel consumption can be improved.
[0045]
Next, a second embodiment of the present invention will be described. Since the hardware configuration of the second embodiment is the same as that of the first embodiment, the description thereof is omitted. In the flowchart of the torque control shown in FIG. 3 executed by the ECU 250 of the first embodiment, torque reduction control of the large torque cylinder group (group G2 and group G22) is not performed for the purpose of improving fuel efficiency. Then, a process for controlling the actual torque of the group of large torque cylinders not controlled by a predetermined amount of torque reduction is added. This is shown in FIG.
[0046]
The process shown in FIG. 7 is a process added after step S325 shown in FIG. After the torque control of the first embodiment is performed up to step S325 shown in FIG. 3, processing is performed to determine whether the combustion pattern currently being processed is pattern A, pattern C or the other (step S700). When the patterns A and C are applicable, a process is performed to determine whether or not the difference ΔT between the predetermined torque T2 and the predetermined torque T1 is equal to or greater than a predetermined value ε2 (step S710). Here, the torque T1 is determined in step S320 shown in FIG. 3, and the torque T2 is set to the maximum detected torque among the detected torques of the large torque cylinder group.
[0047]
An example of torque control of the second embodiment is shown in FIG. FIG. 8A shows the detected torque of each cylinder before the execution of the torque control of the present invention in the order of combustion, and corresponds to the pattern A shown in FIG. By the torque control of the first embodiment, the third cylinder 20c and the second cylinder 20b are respectively controlled toward a predetermined torque T1. In the torque control of the second embodiment, the predetermined torque T2 is set as the maximum detected torque in the first cylinder 20a and the fourth cylinder 20d. When it is determined that the difference ΔT between the two is equal to or greater than a predetermined value ε2 (for example, an allowable amplitude for drivability), the torque T2 is newly replaced with the predetermined torque T3, and the actual torque of the large torque cylinder is changed to the torque T3. Thus, torque reduction control is performed by adjusting the target torque (step S720). FIG. 8B shows the actual torque of each cylinder after torque control. In the torque control of the first embodiment, the cylinder group (the first cylinder 20a and the fourth cylinder 20d) for which the torque reduction control is not executed is controlled to a predetermined torque T3. The predetermined torque T3 is set as a design value having a predetermined width that is allowable for drivability based on the torque T1. On the other hand, if the combustion pattern is other than patterns A and C in step S700, or if the torque difference ΔT is within the predetermined value ε2 in step S710, the process is terminated without performing anything. When the torque control of the second embodiment is executed, the amplitude of the output torque vibration decreases. Accordingly, it is possible to suppress the deterioration of fuel consumption and improve drivability as much as in the first embodiment.
[0048]
Next, a third embodiment of the present invention will be described. Since the hardware configuration of the third embodiment is the same as that of the first embodiment, description thereof is omitted. The torque control of the third embodiment executed by the ECU 250 is replaced with the process shown in FIG. 9, that is, the process for prohibiting the torque increase control of the small torque cylinder, instead of step S325 shown in FIG. In the torque control of the first embodiment, all torque small cylinders execute the torque increase control in step S325 of FIG. 3, but in the torque control of the third embodiment, the detected torque is the lowest in the group of small torque cylinders. A process for determining whether or not the detected torque Tmin of the cylinder is a predetermined torque ε3 is performed (step S325a). As the predetermined torque ε3, the value of the reference torque width (hereinafter referred to as the optimum value ε3) used as the determination criterion in step S305 in FIG. 3 is used. If the lowest detected torque Tmin is greater than or equal to the optimum value ε3 in step S325a, the effect is hardly obtained even if the torque increase control is executed. Therefore, in this case, a process for prohibiting the torque increase control of the detected torque of the small torque cylinder is performed (step S325b).
[0049]
Specifically, the process of resetting the torque T1 and the predetermined value ε1 to the optimum value ε3 and performing the torque reduction control again is performed (step S325c). Then, the process ends. That is, torque increase control is prohibited for the small torque cylinder. On the other hand, if it is determined in step S325a that the minimum detected torque Tmin is smaller than the optimum value ε3, it is assumed that there is room for improving the combustion state of the small torque cylinder. Torque increase control is performed (step S325d). An example of torque control of the third embodiment is shown in FIG. FIG. 10A shows the detected torque of each cylinder before the torque control according to the present invention in the order of combustion, and corresponds to the pattern A shown in FIG. FIG. 10B shows the actual torque of each cylinder after performing the torque control of the third embodiment. As shown in the figure, the second cylinder 20b is determined to be the optimum value, and the torque increase control of the second cylinder 20b, which is a small torque cylinder, is prohibited, and the torque T1 (ie, the second cylinder 20b) shown in FIG. Is detected as a target torque for control. The third cylinder 20c is controlled to lower the torque to a new torque T1. According to the torque control of the third embodiment, it is possible to align the torques of the two cylinders without executing unnecessary control.
[0050]
In the above embodiment, a 4-cylinder internal combustion engine has been described. However, this torque control can also be applied to internal combustion engines such as a 5-cylinder, 6-cylinder, 8-cylinder, and 12-cylinder. In general, FIG. 11 shows a flowchart for executing this torque control in an n-cylinder (n ≧ 4) internal combustion engine. First, an output torque is detected for each of the n cylinders, and a process of determining the number R of large torque cylinders that are consecutive in the combustion order from the magnitude determination of each cylinder torque is performed (step S900). Based on the number R of continuous large torque cylinders, a grouping process is performed in which the n cylinders are divided into two groups (step S910). When the number R of continuous large torque cylinders is 3 or more and n−1 or less, the remaining R−2 cylinders excluding the cylinders at both ends of the continuous large torque cylinder are not consecutive in the combustion order. Classify each other.
[0051]
Here, a typical pattern of the detected torque of the 8-cylinder internal combustion engine is shown in FIG. 12, and the grouping will be described according to this. As in FIG. 4, the horizontal axis represents the combustion order of the cylinders, and the vertical axis represents the torque value. The order of combustion of the eight cylinders is the first, second, seventh, eighth, fourth, fifth, sixth and third cylinders. As shown in the figure, in the representative pattern AA, the number R of continuous large torque cylinders is 7, and the cylinders excluding the first cylinder and the sixth cylinder at both ends thereof are divided into cylinders that are not consecutive in the combustion order. The pattern AA is divided into the second, eighth, and fifth cylinders and others. A third cylinder, which is a small torque cylinder, is added to the second, eighth, and fifth cylinders to form one group. The remaining first, seventh, fourth, and sixth cylinders are set as the other group. Similarly, in the pattern BB, R is 6, and, except for the first and fifth cylinders, they are divided into the second and eighth cylinders that are not consecutive in the combustion order and the other. The 6th and 3rd cylinders of the small torque cylinder are added to the 2nd and 8th cylinders. Hereinafter, when each cylinder is similarly grouped, it is divided into one group indicated by a double circle and the other group indicated by a white circle in the figure. Torque control for adjusting the target torque of each n-cylinder is performed on the cylinder groups thus grouped so that the actual torque is the same for each cylinder group but different between the cylinder groups (step S920), and the process is terminated. . In the pattern AA, torque reduction control is performed on the second, eighth, and fifth cylinders.
[0052]
The grouping shown in FIG. 12 is an example. For example, the pattern AA may be a group including at least one cylinder that is not consecutive in the combustion order. Specifically, the second, eighth and fourth cylinders are divided into the seventh and fifth cylinders, and the third cylinder of the small torque cylinder is added to the seventh and fifth cylinders to form one group, and the rest The other group. In this case, torque reduction control is performed on the seventh and fifth cylinders. Even when such grouping is performed, the output torque vibration cycle becomes short, and deterioration of fuel consumption can be suppressed. In the representative pattern DD, the same effect can be obtained by using the seventh cylinder and the small torque cylinder instead of the second cylinder as one group.
[0053]
An example in which torque control performed on each cylinder divided into two groups by this grouping is applied to a six-cylinder internal combustion engine will be described. FIG. 13 shows the relationship between the combustion order and torque of a 6-cylinder (n = 6) internal combustion engine. The order of combustion on the horizontal axis is the first, fifth, third, sixth, second, and fourth cylinders. The detected torque of each cylinder before this control is performed is indicated by a white circle, and the actual torque after control is indicated by a black circle. is there. R in the figure indicates the number of continuous cylinders among the large torque cylinders. As shown in the drawing, for representative patterns AAA, BBB, and CCC in which R corresponds to 3 to 5, torque reduction control is performed on the cylinders selected based on the above grouping. Therefore, after control, as shown by the black circles in the figure, the output torque vibration period can be shortened, and deterioration of fuel consumption can be suppressed.
[0054]
Note that when all six cylinders are large torque cylinders or when all the cylinders are small torque cylinders, torque reduction control is not performed. This is because there is little output torque vibration and there is little room for improving drivability. Even when there are two or less consecutive cylinders (for example, pattern DDD), torque reduction control is not performed in principle. This is because when there are two consecutive cylinders, it is difficult to improve the cycle of output torque vibration even if torque reduction control is performed on any of the large torque cylinders. Further, if the large torque cylinders do not continue in the combustion order, the magnitude of the torque appears alternately in the combustion order from the beginning, and thus the purpose of this control is achieved. However, when there are two continuous cylinders and two large torque cylinders (for example, pattern EEE), or when there is one large torque cylinder, torque reduction control is performed on the large torque cylinder. As described above, even in a multi-cylinder internal combustion engine, an optimum cylinder is selected according to each combustion pattern and torque control is executed. Therefore, it is possible to perform torque control that balances fuel consumption and drivability.
[0055]
In this embodiment, the output torque of each cylinder is detected. However, by grasping the tendency of variation in output torque from experiments and the like, if a predetermined cylinder is torque controlled, the period of oscillation of the output torque can be shortened. Have the same effect. In this embodiment, the torque control is divided into the torque control of the first embodiment to the third embodiment. However, the present invention is not limited to this, and the torque control is not limited to this. They can also be used in combination.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a control system system in which a control device for an internal combustion engine is mounted according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram of a longitudinal section of one cylinder.
FIG. 3 is a flowchart of torque control processing according to the first embodiment.
FIG. 4 is a relationship diagram between combustion order and torque by control of the first embodiment.
FIG. 5 is a relationship diagram between combustion order and torque by control of the first embodiment.
FIG. 6 is a relationship diagram of air-fuel ratio and torque.
FIG. 7 is a flowchart of torque control processing according to the second embodiment.
FIG. 8 is a relationship diagram between combustion order and torque before and after torque control in the second embodiment.
FIG. 9 is a flowchart of torque control processing according to a third embodiment.
FIG. 10 is a diagram showing the relationship between combustion order and torque before and after torque control in the third embodiment.
FIG. 11 is a flowchart of torque control processing for an n-cylinder internal combustion engine.
FIG. 12 is an explanatory diagram of grouping of an eight-cylinder internal combustion engine.
FIG. 13 is a diagram showing the relationship between the combustion order and torque by torque control of a 6-cylinder internal combustion engine.
[Explanation of symbols]
10 ... Engine
20 ... Cylinder
20a ... 1st cylinder
20b ... 2nd cylinder
20c ... 3rd cylinder
20d ... 4th cylinder
30 ... Cylinder block
40 ... Piston
50 ... Cylinder head
60 ... Intake valve
63 ... Intake camshaft
65 ... Intake port
67 ... Intake cam
70 ... Exhaust valve
73 ... Exhaust camshaft
75 ... Exhaust port
77 ... Exhaust cam
80 ... Combustion chamber
85 ... Spark plug
90 ... Intake manifold
95 ... Intake passage
100 ... Fuel injection valve
110 ... Surge tank
115 ... Air flow meter
120 ... Intake duct
130 ... Air cleaner
140 ... Rocker arm
141 ... Rocker arm
160 ... Exhaust manifold
170 ... oxygen concentration sensor
172 ... Accelerator position sensor
174 ... Crank angle sensor
175 ... Catalytic converter
176 ... Top dead center sensor
178 ... Shaft position sensor
180 ... Cam angle sensor
182 ... Water temperature sensor
200: Mediation drive mechanism
201 ... Control shaft
202 ... input unit
203 ... Oscillating cam
205 ... Laura
207 ... Nose
210 ... Lift amount variable actuator
215 ... Oil control valve
220 ... Rotation phase difference actuator
225 ... Oil control valve
250 ... ECU

Claims (12)

A control device for an internal combustion engine having four or more cylinders,
The combustion state of each cylinder is set so that the oscillation cycle of the output torque generated according to the combustion order of the plurality of cylinders is shorter than the oscillation of the output torque with one cycle being the time until completion of combustion for all cylinders. A control apparatus for an internal combustion engine, comprising adjusting means for adjusting. A control device for an internal combustion engine according to claim 1,
The adjusting means includes
Torque detecting means for detecting output torque for each of a plurality of cylinders of the internal combustion engine at a predetermined timing;
With respect to a plurality of cylinder groups in which the plurality of cylinders are grouped by including at least one cylinder that is not consecutive in the combustion order, the actual torque is the same for each cylinder group but different between the cylinder groups. A control device for an internal combustion engine, comprising: target torque applying means for applying a target torque to be applied to each cylinder included in the cylinder group. A control device for an internal combustion engine according to claim 2,
The target torque applying means sets the actual torque that differs between the cylinder groups to a predetermined torque between the maximum detected torque and the minimum detected torque among the detected torques for each cylinder detected by the torque detecting means. Thus, a control device for an internal combustion engine which is means for adjusting the target torque of the cylinders included in the cylinder group. A control device for an internal combustion engine according to claim 2 or 3,
The control apparatus for an internal combustion engine, wherein the predetermined timing is when the vehicle is idling. A control device for an internal combustion engine according to any one of claims 2 to 4,
The control device for an internal combustion engine, wherein the torque detection means is a means for detecting based on at least one of estimation by detection of rotation fluctuation of the internal combustion engine, estimation by detection of combustion time, and detection of in-cylinder pressure. A control device for an internal combustion engine according to any one of claims 2 to 5,
The target torque applying means is a predetermined torque in which the actual torque of the cylinder group including the cylinder that is the lowest detected torque among the detected torques for each cylinder detected by the torque detecting means is lower than the actual torque of the other cylinder groups. A control device for an internal combustion engine, which is means for adjusting the target torque of the cylinders included in the cylinder group so that the torque becomes the same torque. A control device for an internal combustion engine according to any one of claims 1 to 6,
The internal combustion engine is an internal combustion engine having four cylinders;
One of the grouped cylinder groups is a control device for an internal combustion engine in which when one cylinder is in an expansion stroke, the remaining cylinders are cylinders in an intake stroke. A control device for an internal combustion engine according to any one of claims 1 to 7,
The internal combustion engine is an internal combustion engine that is provided between a rotation of the crankshaft of the internal combustion engine and an intake valve that opens and closes accordingly, and includes a variable valve mechanism that changes the opening and closing timing of the intake valve. Engine control device. A control device for an internal combustion engine according to any one of claims 1 to 8,
The control device for an internal combustion engine, wherein the adjusting means includes means for controlling the detected torque for each cylinder based on at least one of control of the air-fuel ratio of the internal combustion engine and control of ignition timing. A control device for an internal combustion engine according to any one of claims 2 to 9,
The target torque applying means calculates the actual torque of the cylinder group including the cylinder that is the maximum detected torque among the detected torques for each cylinder detected by the torque detecting means, and the cylinder that is the actual torque and the lowest detected torque. A control device for an internal combustion engine, which is means for adjusting the target torque of a cylinder included in the cylinder group so that a difference from an actual torque of the included cylinder group is within a predetermined value. A control device for an internal combustion engine according to any one of claims 2 to 10,
The target torque applying means is included in a cylinder group when the detected torque of the cylinder, which is the lowest detected torque among the detected torques for each cylinder detected by the torque detecting means, is a predetermined torque. A control apparatus for an internal combustion engine, which is a means for prohibiting adjustment of the target torque of a cylinder that increases the detected torque in the cylinder. This is a grouping method in which four or more cylinders are divided into two or more cylinder groups, and the plurality of cylinders are divided into at least two groups in order to control the actual torque which is the same for each cylinder group and is different between the cylinder groups. And
The plurality of cylinders of 4 or more are n cylinders (n is an integer of 4 or more), and among the cylinders exhibiting a large output torque in the n cylinders, the number of cylinders R (R is an integer of 3 or more) consecutive in the combustion order A control cylinder grouping method in which, when n-1 or less, the remaining cylinders excluding the cylinders at both ends of the continuous cylinders are grouped by including at least one cylinder that is not continuous in the combustion order.

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