JP6428585B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine.

  A plurality of cylinders, and a variable compression ratio mechanism capable of simultaneously changing the mechanical compression ratio by a control shaft, wherein the plurality of cylinders are arranged substantially along an engine length direction axis, and the control shaft is the engine A control device for an internal combustion engine that extends substantially along a longitudinal axis is known (see, for example, Patent Document 1). In the variable compression ratio mechanism of Patent Document 1, the relative position of the crankcase and the cylinder block in the cylinder axis direction is changed by rotating the control shaft around its longitudinal axis, thereby changing the mechanical compression ratio. Is done. Specifically, when the cylinder block is moved away from the crankcase, the combustion chamber volume of each cylinder is increased, and therefore the mechanical compression ratio is decreased. On the other hand, when the cylinder block is brought closer to the crankcase, the combustion chamber volume of each cylinder is reduced, and therefore the mechanical compression ratio is increased.

JP 2012-145045 A

  By the way, when combustion is performed in each cylinder, the cylinder block is urged away from the crankcase by the combustion pressure. In this case, when the cylinder block moves relative to the crankcase, the volume in the combustion chamber is increased, the mechanical compression ratio is reduced with respect to the normal value, and therefore the indicated torque or generated torque is reduced.

  The cylinder block moves relative to the combustion pressure because, for example, the control shaft of the variable compression ratio mechanism is elastically deformed by the combustion pressure, or within a slight gap provided between the control shaft and the cylinder block and the crankcase. This is probably because the control axis moves. For this reason, the cylinder block relative movement amount is relatively large in the cylinder located outside the engine length direction, and the cylinder block relative movement amount is relatively small in the cylinder located inside the engine length direction. As a result, the amount of torque decrease is relatively large in the cylinder located on the outer side in the engine length direction, and the amount of torque decrease is relatively small in the cylinder located on the inner side in the engine length direction. That is, there is a possibility that the amount of torque decrease due to the decrease in the mechanical compression ratio varies between cylinders. Therefore, the generated torque may vary between the cylinders.

  According to the present invention, comprising a plurality of cylinders and a variable compression ratio mechanism capable of changing the mechanical compression ratio by a control shaft, the plurality of cylinders are arranged substantially along the engine length direction axis, A control shaft is a control device for an internal combustion engine extending substantially along the engine length direction axis, and calculating means for calculating a torque reduction amount for each cylinder due to an increase in a combustion chamber volume due to combustion pressure; There is provided a control device for an internal combustion engine, comprising: adjusting means for adjusting the generated torque of each of the plurality of cylinders based on the torque reduction amount so that the torque reduction amounts of the plurality of cylinders are substantially equal to each other. .

  The variation in the generated torque between the cylinders can be reduced.

1 is an overall view of a spark ignition internal combustion engine. It is a disassembled perspective view of a variable compression ratio mechanism. 1 is a schematic side sectional view of an internal combustion engine. It is a mimetic diagram for explaining indicated torque TQi (j) of the jth cylinder. It is a schematic diagram for demonstrating torque fall amount (DELTA) TQd (j) of jth cylinder. It is a schematic diagram for demonstrating torque adjustment amount (DELTA) TQa (j) of jth cylinder. It is a figure which shows basic ignition timing SAb. It is a figure which shows ignition timing correction value (DELTA) SA (j). It is a figure which shows torque fall amount (DELTA) TQd (j). It is a schematic diagram for demonstrating a pitch direction, a roll direction, and a yaw direction. It is a figure which shows combustion chamber volume increase part (DELTA) Vp, (DELTA) Vr, and (DELTA) Vy. It is a figure which shows basic in-cylinder pressure peak value Ppb. It is a figure which shows the 1st correction coefficient kPp1. It is a figure which shows the 2nd correction coefficient kPp2. It is a schematic diagram for demonstrating the distance L (j) of jth cylinder. It is a flowchart for calculating the torque adjustment amount ΔTQa (j) of the j-th cylinder. It is a flowchart for performing ignition timing control.

  FIG. 1 shows an overall view of the internal combustion engine EG. In an embodiment according to the present invention, the internal combustion engine EG comprises a spark ignition type internal combustion engine. In another embodiment not shown, the internal combustion engine comprises a compression ignition type internal combustion engine. The internal combustion engine EG shown in FIG. 1 includes a plurality of, for example, four cylinders.

  Referring to FIG. 1, 1 is a crankcase, 2 is a cylinder block, 3 is a cylinder head, 4 is a piston, 5 is a combustion chamber, 6 is a spark plug disposed at the center of the top surface of the combustion chamber 5, and 7 is intake air. 8 is an intake port, 9 is an exhaust valve, and 10 is an exhaust port. The intake port 8 is connected to a surge tank 12 via an intake branch pipe 11, and a fuel injection valve 13 for injecting fuel into the corresponding intake port 8 is arranged in each intake branch pipe 11. In another embodiment (not shown), the fuel injection valve 13 is disposed in each combustion chamber 5.

  The surge tank 12 is connected to an air cleaner 15 via an intake duct 14, and a throttle valve 17 driven by an actuator 16 and an intake air amount detector 18 using, for example, heat rays are arranged in the intake duct 14. On the other hand, the exhaust port 10 is connected to a catalytic converter 20 containing, for example, a three-way catalyst via an exhaust manifold 19, and an air-fuel ratio sensor 21 is disposed in the exhaust manifold 19.

  On the other hand, in the embodiment according to the present invention, the mechanical compression ratio of the internal combustion engine can be changed by changing the relative position of the crankcase 1 and the cylinder block 2 in the cylinder axial direction at the connecting portion between the crankcase 1 and the cylinder block 2. A compression ratio mechanism A is provided. When the volume of the combustion chamber when the piston is located at the compression top dead center is referred to as the combustion chamber volume, the mechanical compression ratio is a value that is mechanically determined only from the piston stroke volume and the combustion chamber volume during the compression stroke. (Combustion chamber volume + stroke volume) / combustion chamber volume.

  The electronic control unit 30 is composed of a digital computer, and is connected to each other by a bidirectional bus 31. A ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, a CPU (Microprocessor) 34, an input port 35 and an output port 36. It comprises. The output signal of the intake air amount detector 18 and the output signal of the air-fuel ratio sensor 21 are input to the input port 35 via the corresponding AD converters 37, respectively. A load sensor 41 that generates an output voltage proportional to the depression amount L of the accelerator pedal 40 is connected to the accelerator pedal 40, and the output voltage of the load sensor 41 is input to the input port 35 via the corresponding AD converter 37. . Further, a crank angle sensor 42 that generates an output pulse every time the crankshaft rotates, for example, 30 ° is connected to the input port 35. Further, a position sensor 43 for detecting the relative position of the cylinder block 2 with respect to the crankcase 1 is provided, and the output voltage of the position sensor 43 is input to the input port 35 via the corresponding AD converter 37. The relative position of the cylinder block 2 with respect to the crankcase 1 represents the mechanical compression ratio. On the other hand, the output port 36 is connected to the spark plug 6, the fuel injection valve 13, the throttle valve drive actuator 16, and the variable compression ratio mechanism A through a corresponding drive circuit 38. The electronic control unit 30 constitutes the calculation means and adjustment means of the present invention.

  2 is an exploded perspective view of the variable compression ratio mechanism A shown in FIG. 1, and FIGS. 3A and 3B are side sectional views of the internal combustion engine schematically shown. Referring to FIG. 2, a plurality of projecting portions 50 spaced from each other are formed below both side walls of the cylinder block 2, and cam insertion holes 51 each having a circular cross section are formed in each projecting portion 50. Has been. On the other hand, a plurality of protrusions 52 are formed on the upper wall surface of the crankcase 1 so as to be fitted between the corresponding protrusions 50 with a space between each other. Cam insertion holes 53 each having a circular cross section are formed.

  The variable compression ratio mechanism A includes a control shaft common to a plurality of cylinders. In the example shown in FIG. 2, the control shaft includes a pair of cam shafts 54, 55, and circular cams 56 that are rotatably inserted into the cam insertion holes 51 on the cam shafts 54, 55. It is fixed. These circular cams 56 are coaxial with the longitudinal axis of each camshaft 54, 55 or the rotational axis LA. On the other hand, an eccentric shaft 57 arranged eccentrically with respect to the rotation axis LA of each camshaft 54, 55 extends between the circular cams 56 as shown by hatching in FIG. A circular cam 58 is eccentrically mounted for rotation. As shown in FIG. 2, the circular cams 58 are disposed between the circular cams 56, and the circular cams 58 are rotatably inserted into the corresponding cam insertion holes 53.

  When the circular cams 56 fixed on the camshafts 54 and 55 are rotated in opposite directions as indicated by solid arrows in FIG. 3A from the state shown in FIG. In order to move toward the lower center, the circular cam 58 rotates in the opposite direction to the circular cam 56 in the cam insertion hole 53 as shown by the broken arrow in FIG. 3A, and is shown in FIG. As described above, when the eccentric shaft 57 moves to the lower center, the center of the circular cam 58 moves below the eccentric shaft 57.

  3A and 3B, the relative positions of the crankcase 1 and the cylinder block 2 are determined by the distance between the center of the circular cam 56 and the center of the circular cam 58. The cylinder block 2 moves away from the crankcase 1 as the distance between the center and the center of the circular cam 58 increases. When the cylinder block 2 moves away from the crankcase 1, the combustion chamber volume increases, so that the combustion chamber volume or the mechanical compression ratio can be changed by rotating the camshafts 54 and 55.

  As shown in FIG. 2, in order to rotate the camshafts 54 and 55 in opposite directions, a pair of worms 61 and 62 having opposite spiral directions are attached to the rotation shaft of the drive motor 59, respectively. Worm wheels 63 and 64 that mesh with the worms 61 and 62 are fixed to the ends of the camshafts 54 and 55, respectively. In this case, by driving the drive motor 59, the volume of the combustion chamber 5 when the piston 4 is located at the compression top dead center is changed, and thus the opportunity compression ratio is changed. In the embodiment according to the present invention, the variable compression ratio mechanism A is controlled so that the mechanical compression ratio becomes a target mechanical compression ratio determined according to the engine operating state, for example, the engine load factor KL and the engine speed Ne.

  In FIG. 2, LL indicates the engine length direction, LW indicates the engine width direction, and LH indicates the engine height direction. The engine length direction LL, the engine width direction LW, and the engine height are shown. The directions LH are orthogonal to each other. As shown in FIG. 2, the cylinders of the internal combustion engine EG are disposed substantially along the engine length direction LL axis. The camshafts 54 and 55 of the variable compression ratio mechanism A extend substantially along the engine length direction LL axis.

  In another embodiment of the variable compression ratio mechanism A, the piston pin and the crank pin are connected to each other via the upper link and the lower link connected to each other, and the operation of the control link connected to the lower link is controlled by the control shaft. Is changed, thereby changing the piston position at the starting point of compression, and thus changing the mechanical compression ratio (multi-link piston stroke mechanism). In still another embodiment of the variable compression ratio mechanism A, the cylinder head is provided so as to be movable relative to the cylinder block, and the relative position of the cylinder head with respect to the cylinder block is changed by the control shaft, whereby the mechanical compression ratio is changed. Is done.

  Now, as explained at the beginning, the cylinder block 2 is moved relative to the crankcase 1 by the combustion pressure of each cylinder and the combustion chamber volume of each cylinder is increased, thereby reducing the indicated torque or generated torque of each cylinder. There is a risk. FIG. 4 schematically shows a decrease amount ΔTQd (j) (≧ 0) of the indicated torque TQi (j) of the j-th cylinder (j = 1, 2, 3, 4). In the example shown in FIG. 4, the indicated torque TQi (j) of the j-th cylinder is obtained from the indicated torque of each cylinder when the cylinder block 2 is not moved relative to the crankcase 1, that is, from the reference torque TQiR. Each decrease is caused by a decrease amount ΔTQd (j) (≧ 0).

  In the example shown in FIG. 4, the torque reduction amount ΔTQd (1) of the first cylinder and the torque reduction amount ΔTQd (4) of the fourth cylinder are substantially equal to each other, and the torque reduction amounts ΔTQd (2) and 3 of the second cylinder are the same. The torque reduction amount ΔTQd (3) of the numbered cylinder is substantially equal to each other. Further, the torque decrease amount ΔTQd (1) of the first cylinder located outside the length direction LL of the cylinder block 2 and the torque decrease amount ΔTQd (4) of the fourth cylinder are the inside of the cylinder block 2 in the length direction LL. This is larger than the torque reduction amount ΔTQd (2) of the second cylinder located at 及 び and the torque reduction amount ΔTQd (3) of the third cylinder, and is the largest among the torque reduction amounts ΔTQd (j) of the jth cylinder. FIG. 5 shows the torque reduction amount ΔTQd (j) of the j-th cylinder with the vertical axis.

  Thus, the indicated torque TQi (j) and the torque decrease amount ΔTQd (j) of the j-th cylinder vary. If the torque varies between cylinders in this way, engine vibration and noise may increase undesirably. Therefore, in the embodiment according to the present invention, the torque decrease amount ΔTQd (j) resulting from the increase in the combustion chamber volume due to the combustion pressure is calculated for each cylinder so that the torque decrease amounts ΔTQd (j) of the plurality of cylinders are substantially equal to each other. In addition, the torque generated by the plurality of cylinders is adjusted based on the torque reduction amount ΔTQd (j).

  First, a method for adjusting the generated torque in the embodiment according to the present invention will be described. In the embodiment according to the present invention, the target torque decrease amount ΔTQdt is set, and the generated torque of the j-th cylinder is adjusted so that the torque decrease amount ΔTQd (j) of the j-th cylinder becomes the target torque decrease amount ΔTQdt. In the embodiment according to the present invention, the target torque reduction amount ΔTQdt is set to the maximum among the torque reduction amounts ΔTQd (j) of the j-th cylinder. In the example shown in FIG. 5, since the torque decrease amount ΔTQd (1) (= ΔTQd (4)) of the first cylinder # 1 is the maximum, the target torque decrease amount ΔTQdt is the torque decrease amount ΔTQd ( 1). FIG. 6 shows the relationship between the torque decrease amount ΔTQd (j) and the target torque decrease amount ΔTQdt shown in FIG.

  Next, a torque adjustment amount ΔTQa (j) required to make the torque decrease amount ΔTQd (j) of the j-th cylinder the target torque decrease amount ΔTQdt is calculated (ΔTQa (j) = ΔTQdt−ΔTQd (j)). The torque adjustment amount ΔTQa (j) of the jth cylinder is a positive value when the generated torque of the jth cylinder is to be reduced, and the torque adjustment amount ΔTQa (j) of the jth cylinder is when the generated torque of the jth cylinder is to be increased. Negative value. In the example shown in FIG. 6, the torque adjustment amount ΔTQa (1) of the first cylinder # 1 and the torque adjustment amount ΔTQa (4) of the fourth cylinder # 4 are zero, and the torque adjustment amount ΔTQa of the second cylinder # 2 The torque adjustment amount ΔTQa (3) of (2) and the third cylinder # 3 is “ΔTQdt−ΔTQ”. That is, the torque reduction amounts ΔTQd (1) and ΔTQd (4) are not changed in the first cylinder # 1 and the fourth cylinder # 4. On the other hand, in the second cylinder # 2 and the third cylinder # 3, the torque reduction amounts ΔTQd (2) and ΔTQd (3) are increased by the torque adjustment amounts ΔTQa (2) and ΔTQa (3), or the generated torque is increased. The torque adjustment amounts are decreased by ΔTQa (2) and ΔTQa (3).

Various methods are known for adjusting the generated torque or the torque decrease amount. In the embodiment according to the present invention, the generated torque or the torque decrease amount is adjusted by adjusting the ignition timing. Specifically, the ignition timing SA (j) (crank angle) of the j-th cylinder is calculated using, for example, the following equation.
SA (j) = SAb + ΔSA (j)
Here, SAb represents the basic ignition timing, and ΔSA (j) represents the ignition timing correction value for the j-th cylinder.

  The basic ignition timing SAb is obtained in advance as a function of the engine operating state, for example, the engine load factor KL and the engine speed Ne, and is stored in advance in the ROM 32 in the form of a map shown in FIG. The engine load factor KL (%) is the ratio of the engine load to the total load.

  The ignition timing correction value ΔSA (j) is for adjusting the torque generated in the j-th cylinder by the torque adjustment amount ΔTQa (j) described above. The ignition timing correction value ΔSA (j) is zero when the torque adjustment amount ΔTQa (j) is zero, and increases as the torque adjustment amount ΔTQa (j) increases. That is, the ignition timing SA (j) is retarded as the torque adjustment amount ΔTQa (j) increases. The ignition timing correction value ΔSA (j) is stored in advance in the ROM 32 in the form of a map shown in FIG.

  As a result, the torque reduction amount ΔTQd (j) of each cylinder becomes substantially equal to each other. Accordingly, the generated torque amounts of the cylinders are substantially equal to each other. In this way, engine vibration and noise are suppressed.

  Next, a method of calculating the torque decrease amount ΔTQd (j) of the j-th cylinder in the embodiment according to the present invention will be described. As described above, the combustion chamber volume increases due to the combustion pressure in each cylinder, and the torque decreases. In this case, as shown in FIG. 9, the torque decrease amount ΔTQd (j) of the jth cylinder increases as the increase ΔV (j) in the combustion chamber volume due to the combustion pressure of the jth cylinder increases. Therefore, in the embodiment according to the present invention, the combustion chamber volume increase ΔV (j) of the j-th cylinder is calculated first, and then the torque decrease amount ΔTQd (j) of the j-th cylinder is calculated using the map of FIG. The torque reduction amount ΔTQd (j) of the j-th cylinder is stored in advance in the ROM 32 in the form of a map shown in FIG.

The combustion chamber volume increase ΔV (j) of the j-th cylinder is calculated as follows, for example. As described above, the torque decrease amount ΔTQd (j) of the j-th cylinder varies, and therefore, the increase in the combustion chamber volume due to the combustion pressure of the j-th cylinder also varies. When the cylinder in which the increase in the combustion chamber volume due to the combustion pressure is maximized is referred to as the maximum volume increase cylinder, in the embodiment according to the present invention, the combustion chamber volume increase ΔVm of the maximum volume increase cylinder is first calculated. The combustion chamber volume increase ΔVm of the maximum volume increase cylinder is calculated using, for example, the following equation.
ΔVm = ΔVp + ΔVr + ΔVy
Here, ΔVp is the increase in the combustion chamber volume in the pitch direction in the maximum volume increase cylinder, ΔVr is the increase in the combustion chamber volume in the roll direction in the maximum volume increase cylinder, and ΔVy is the combustion chamber volume in the yaw direction in the maximum volume increase cylinder. Each increase is shown. The pitch direction is a direction around the central axis LWC extending in the width direction LW as indicated by an arrow P in FIG. Further, the roll direction is a direction around the central axis LLC extending in the length direction LL as indicated by the arrow R in FIG. 10, and the yaw direction is the center extending in the height direction LH as indicated by the arrow Y in FIG. This is the direction around the axis LHC.

  As described above, the increase in the combustion chamber volume due to the combustion pressure is caused by the relative movement of the cylinder block 2 with respect to the crankcase 1. This relative movement of the cylinder block 2 can be divided into a relative movement in the pitch direction, a relative movement in the roll direction, and a relative movement in the yaw direction, and the combustion chamber volume increase is also caused by the relative movement in the pitch direction. This can be divided into a volume increase ΔVp, a combustion chamber volume increase ΔVr caused by relative movement in the roll direction, and a combustion chamber volume increase ΔVy caused by relative movement in the yaw direction.

  When the maximum value of the in-cylinder pressure of each cylinder when it is assumed that the cylinder block 2 does not move relative to the crankcase 1 due to the combustion pressure is referred to as an in-cylinder pressure peak value Pp, combustion in the pitch direction is performed as shown in FIG. The chamber volume increase ΔVp, the combustion chamber volume increase ΔVr in the roll direction, and the combustion chamber volume increase ΔVy in the yaw direction increase as the in-cylinder pressure peak value Pp increases. Further, the combustion chamber volume increase ΔVp in the pitch direction is larger than the combustion chamber volume increase ΔVr in the roll direction and the combustion chamber volume increase ΔVy in the yaw direction. These combustion chamber volume increases ΔVp, ΔVr, ΔVy are stored in advance in the ROM 32 in the form of a map shown in FIG. 11 as a function of the in-cylinder pressure peak value Pp.

The in-cylinder pressure peak value Pp is calculated using the following equation, for example.
Pp = Ppb · kPp1 · kPp2
Here, Ppb represents a basic in-cylinder pressure peak value, kPp1 represents a first correction coefficient (0 <kPp1 ≦ 1), and kPp2 represents a second correction coefficient (0 <kPp2).

  The basic in-cylinder pressure peak value Ppb is an in-cylinder pressure peak value when the engine operating state represented by, for example, the EGR rate and the equivalence ratio (air-fuel ratio) is in the basic state, and as shown in FIG. 12, the engine load factor KL It becomes higher as becomes larger. The basic in-cylinder pressure peak value Ppb is stored in advance in the ROM 32 as a function of the engine load factor KL in the form of a map shown in FIG. In the embodiment according to the present invention, the engine operating state is in the basic state when the EGR rate REGR is zero and the equivalence ratio φ is 1 (theoretical air-fuel ratio). The EGR rate REGR is a ratio of the EGR gas amount to the in-cylinder gas amount (air amount + EGR gas amount).

  The first correction coefficient kPp1 is for correcting the basic in-cylinder pressure peak value Ppb based on the EGR rate REGR. As shown in FIG. 13, the first correction coefficient kPp1 is 1 when the EGR rate REGR is zero, and decreases as the EGR rate REGR increases. The first correction coefficient kPp1 is stored in advance in the ROM 32 in the form of a map shown in FIG.

  The second correction coefficient kPp2 is for correcting the basic in-cylinder pressure peak value Ppb based on the equivalence ratio φ. As shown in FIG. 14, the second correction coefficient kPp2 is 1 when the equivalence ratio φ is 1, and increases as the equivalence ratio φ increases. The second correction coefficient kPp2 is stored in advance in the ROM 32 in the form of a map shown in FIG.

  In this way, the in-cylinder pressure peak value Pp is calculated from the basic in-cylinder pressure peak value Ppb, the first correction coefficient kPp1, and the second correction coefficient kPp2, and the combustion chamber volume increases ΔVp, ΔVr, ΔVy is calculated, and the combustion chamber volume increase ΔVm of the maximum volume increase cylinder is calculated from the combustion chamber volume increase ΔVp, ΔVr, ΔVy.

  FIG. 15 shows distances L (j) from the center LL0 in the length direction LL of the cylinder block 2 to the cylinder axis C (j) of the j-th cylinder. In FIG. 15, B (j) represents the cylinder bore of the j-th cylinder, and LCB represents the length of the cylinder block 2 in the length direction LL. In the example shown in FIG. 15, the distance L (1) of the first cylinder # 1 and the distance L (4) of the fourth cylinder # 4 are substantially equal to each other, the distance L (2) and the third number of the second cylinder # 2. The distance L (3) of cylinder # 3 is substantially equal to each other. Further, the distance L (1) of the first cylinder # 1 and the distance L (4) of the fourth cylinder # 4 are the largest of the distances L (j) of the jth cylinder. In the embodiment according to the present invention, it is assumed that the cylinder having the longest distance L (j) is the maximum volume increase cylinder, and therefore, the first cylinder # 1 and the fourth cylinder # 4 are the maximum volume increase cylinder. doing. For this reason, the combustion chamber volume increase ΔVm calculated as described above becomes the combustion chamber volume increase ΔV (1) of the first cylinder # 1 and the combustion chamber volume increase ΔV (4) of the fourth cylinder # 4. Equivalent to.

  On the other hand, the remaining cylinder, that is, the combustion chamber volume increase ΔV (2) of the second cylinder # 2 and the combustion chamber volume increase ΔV (3) of the third cylinder # 4 are calculated as follows, for example. In the embodiment according to the present invention, it is assumed that the combustion chamber volume increase ΔV (j) of the j-th cylinder increases as the distance L (j) of the j-th cylinder increases. Therefore, the combustion chamber volume increase ΔV (2) of the second cylinder # 2 is (L (2) / L (1)) times the combustion chamber volume increase ΔV (1) of the first cylinder # 1. (ΔV (2) = ΔV (1) · (L (2) / L (1))). The combustion chamber volume increase ΔV (3) of the third cylinder # 3 is equal to the combustion chamber volume increase ΔV (2) of the second cylinder # 2.

  When the combustion chamber volume increase ΔV (j) of the j-th cylinder is calculated in this way, the torque decrease amount ΔTQd (j) of the j-th cylinder is calculated using the map of FIG. 9 as described above. Next, the target torque decrease amount ΔTQdt is set, and the generated torque of the jth cylinder is adjusted so that the torque decrease amount ΔTQd (j) of the jth cylinder becomes the target torque decrease amount ΔTQdt.

  FIG. 16 shows a routine for calculating the torque adjustment amount ΔTQa (j) of the j-th cylinder according to the embodiment of the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 16, in step 100, the basic in-cylinder pressure peak value Ppb is calculated using the map of FIG. In the subsequent step 101, the first correction coefficient kPp1 is calculated using the map of FIG. In the subsequent step 102, the second correction coefficient kPp2 is calculated using the map of FIG. In the subsequent step 103, the in-cylinder pressure peak value Pp is calculated (Pp = Ppb · kPp1 · kPp2). In the following step 104, the combustion chamber volume increases ΔVp, ΔVr, and ΔVy are respectively calculated in the map of FIG. In the following step 105, the combustion chamber volume increase ΔVm of the maximum volume increase cylinder is calculated (ΔVm = ΔVp + ΔVr + ΔVy). In the subsequent step 106, the combustion chamber volume increase ΔV (j) of the j-th cylinder is calculated. In the subsequent step 107, the torque reduction amount ΔTQd (j) of the j-th cylinder is calculated using the map of FIG. In the following step 108, the torque adjustment amount ΔTQa (j) of the j-th cylinder is calculated.

  FIG. 17 shows a routine for executing the ignition control of the embodiment according to the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 17, in step 200, the basic ignition timing SAb is calculated using the map of FIG. In the following step 201, the ignition timing correction value ΔSA (j) for the j-th cylinder is calculated using the map of FIG. In the subsequent step 202, the ignition timing SA (j) of the j-th cylinder is calculated (SA (j) = SAb + ΔSA (j)). In the subsequent step 203, an ignition action is executed in the spark plug 6.

  In another embodiment according to the present invention, the generated torque or torque decrease amount ΔTQd (j) is adjusted by adjusting the fuel injection amount or the equivalence ratio. In this case, it is preferable that the target torque decrease amount ΔTQdt is set between the maximum and minimum values of the torque decrease amount ΔTQd (j) of the j-th cylinder. In this way, the fuel injection amount is decreased or the air-fuel ratio is shifted to the lean side in order to increase the torque decrease amount ΔTQd (j) in some cylinders. On the other hand, in the remaining cylinders, the fuel injection amount is increased in order to decrease the torque decrease amount ΔTQd (j), or the air-fuel ratio is shifted to the rich side. As a result, it becomes possible to maintain the air-fuel ratio of the exhaust gas while suppressing the variation in torque decrease amount ΔTQd (j) between the cylinders. The air-fuel ratio of the exhaust gas is the ratio of air and fuel supplied to the exhaust passage, the combustion chamber, and the intake passage upstream from the position where the exhaust passage is located.

1 Crankcase 2 Cylinder block A Variable compression ratio mechanism 54,55 Camshaft

Claims (1)

A plurality of cylinders and a variable compression ratio mechanism capable of changing a mechanical compression ratio by a control shaft, wherein the plurality of cylinders are arranged substantially along an engine length direction axis, and the control shaft is the engine length A control device for an internal combustion engine, extending substantially along a longitudinal axis,
Calculating means for calculating for each cylinder a torque reduction amount caused by an increase in the combustion chamber volume due to the combustion pressure;
Adjusting means for respectively adjusting the generated torques of the plurality of cylinders based on the torque reduction amounts so that the torque reduction amounts of the plurality of cylinders are substantially equal to each other;
The control apparatus of the internal combustion engine provided with.

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