JP5229143B2 - Engine control device - Google Patents

Description

  The present invention relates to a control device for an engine (internal combustion engine), and more particularly to a device for avoiding knocking during deceleration and reacceleration of a vehicle.

  It is generally known that increasing the compression ratio improves the thermal efficiency of the engine. However, if the compression ratio is increased too much, knocking (abnormal combustion) occurs, so that the compression ratio cannot be increased much particularly in a high load region. For this reason, in some engines where the compression ratio can be made variable, the target compression ratio is set to be large in the low load region and small in the high load region, thereby trying to improve fuel consumption without causing knocking ( Patent Document 1).

JP 2006-161630 A

  By the way, even if the compression ratio actuator is controlled so as to obtain the target compression ratio, knocking may occur when the vehicle is decelerated and re-accelerated from the current supercharging pressure state.

  Accordingly, an object of the present invention is to avoid the occurrence of knocking when the vehicle is decelerated and reaccelerated from the current supercharging pressure state.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention includes a compression ratio variable mechanism capable of changing the compression ratio of the engine, a target compression ratio setting means (53) for setting the target compression ratio, and a compression ratio variable mechanism for achieving the set target compression ratio. Control means (35) for controlling, turbocharger (45) driven by exhaust, intake air amount adjusting means (27) for adjusting intake air amount, and intake air amount adjusting means (27) are used. And intake air amount control means (35) for controlling the intake air amount in accordance with operating conditions. On the premise of this, knocking advance determination means (54) for determining in advance whether or not knocking may occur when the vehicle is decelerated and reaccelerated from the current supercharging pressure state, and this determination means When it is determined that there is a possibility that knocking may occur when the vehicle is decelerated and re-accelerated from the current supercharging pressure state, the target compression ratio reduction correction means (55, 55) corrects the target compression ratio to the reduction side. 56).

  According to the present invention, when the throttle valve is opened by deceleration and reacceleration in a state where the actual supercharging pressure is high as in a high load state, the decrease in the actual supercharging pressure is delayed due to the response delay of the turbocharger. However, the compression ratio can be lowered in accordance with the delay, and the occurrence of knocking when the vehicle is decelerated and reaccelerated while the supercharging pressure is high can be avoided.

It is a schematic block diagram of the engine control apparatus of 1st Embodiment of this invention. It is a characteristic view of an intake valve operating angle target value. It is a characteristic figure of a base throttle valve opening. It is a schematic block diagram of a compression ratio variable mechanism. It is a posture figure of each link in a high compression ratio position and a low compression ratio position. FIG. 6 is a characteristic diagram of a target intake air amount. It is a characteristic figure of a target compression ratio basic value. It is a timing chart which shows the effect | action by the present condition control at the time of the deceleration deceleration acceleration of a vehicle. It is a timing chart which shows the effect | action by 1st Embodiment at the time of deceleration re-acceleration of a vehicle. It is the schematic which showed the function of the compression ratio control of 1st Embodiment with the block. It is a flowchart for demonstrating calculation of a target compression ratio. It is a flowchart for demonstrating calculation of a target compression ratio. FIG. 10 is a characteristic diagram of map contents defining boundaries of knocking occurrence regions at three target compression ratio basic values. It is a characteristic diagram of the correction amount. It is a characteristic view for demonstrating the correction method of a basic map. It is a characteristic view of a compression ratio correction amount basic value. It is a characteristic view of a rotational speed correction factor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a control device for an engine 1 according to an embodiment of the present invention. The engine 1 is mounted on a vehicle (not shown).

  In FIG. 1, an intake passage 23 and an exhaust passage 24 are opened in the combustion chamber 21 of the engine 1, and an intake valve 25 is opened at an opening end of the intake passage 23 to the combustion chamber 21, and an opening of the exhaust passage 24 to the combustion chamber 21. An exhaust valve 26 is provided at the end.

  The intake valve 25 includes a lift variable mechanism 27 capable of continuously increasing or decreasing a lift characteristic of the intake valve 25, specifically, a lift amount and an operating angle of the intake valve 25, and a maximum of the intake valve 25. And a phase variable mechanism capable of continuously changing the phase of the crank angle position (that is, the lift center angle of the intake valve 25) that reaches the lift to the advance side or the retard side. Since the mechanical configurations of the lift variable mechanism 27 and the phase variable mechanism 28 are known, a detailed description thereof will be omitted.

  In the engine 1 including the variable lift mechanism 27 and the variable phase mechanism 28, the lift amount and operating angle of the intake valve 25 and the phase of the lift center angle of the intake valve 25 are controlled in accordance with operating conditions to flow into the combustion chamber 21. Since the amount of intake air can be controlled, the pumping loss can be reduced compared to the case where the amount of intake air flowing into the combustion chamber 21 is controlled by the throttle valve opening, and the fuel efficiency is improved accordingly. is there.

  For this reason, in this embodiment, by searching a map having the contents shown in FIG. 2 from the accelerator opening APO and the engine speed Ne, the target value of the lift amount and operating angle of the intake valve 5 (hereinafter simply referred to as “intake valve operation”). "An angle target value") is calculated. As shown in FIG. 2, under the condition of the target intake pressure (described later), the intake valve operating angle target value is a value that increases as the accelerator opening APO increases and the engine speed Ne increases. This is to increase the intake valve operating angle and increase the amount of intake air flowing into the combustion chamber 21 and increase the torque generated by the engine as the accelerator opening APO increases and the engine speed Ne increases. It is.

  In the present embodiment, when the intake air amount is controlled by changing the lift amount and the operating angle of the intake valve 25, a certain slight negative pressure is generated in the intake passage 23 basically regardless of the operating condition, The followability to the target value of the amount of air actually sucked into the combustion chamber 21 is enhanced. When the atmospheric pressure is zero based, the pressure lower than the atmospheric pressure is “negative pressure” (negative pressure). The negative pressure in the intake passage 23 is also effective for blow-by gas processing. In response to this requirement, the intake passage 23 is provided with a throttle valve 29 (throttle valve device) whose opening degree is controlled by an actuator 30 such as a motor. Further, a throttle sensor 31 for detecting the actual throttle valve opening is provided.

  A base throttle valve opening TVObase corresponding to the accelerator opening APO and the engine rotational speed Ne is determined in advance so that the intake pressure generated downstream of the throttle valve 29 becomes the target intake pressure, and this base throttle valve opening TVObase is The throttle valve opening is controlled so as to be obtained. In the present embodiment, the base throttle valve opening TVObase is calculated by searching a map having the contents shown in FIG. 3 from the accelerator opening APO and the engine speed Ne. As shown in FIG. 3, the base throttle valve opening TVObase may be adapted so that a target intake air amount corresponding to the accelerator opening APO and the engine speed Ne is obtained under the condition of the target intake pressure.

  A fuel injection valve 33 is provided at the intake port of the intake passage 23, and a spark plug 34 is provided at the ceiling of the combustion chamber 21. A fuel injection amount for obtaining the target air-fuel ratio is calculated based on the intake air flow rate detected by the air flow meter 38, and fuel of this injection amount is injected and supplied from the fuel injection valve 33 at a predetermined timing. The formed air-fuel mixture is ignited by a spark plug 34 at a predetermined timing.

  The engine includes a variable compression ratio mechanism capable of continuously changing the compression ratio. This engine having a variable compression ratio mechanism has been previously proposed by the present applicant, and is known, for example, from Japanese Patent Application Laid-Open No. 2001-227367. Therefore, only the outline will be described with reference to FIG.

  In FIG. 4, the crankshaft 2 is provided with a crank journal 3 that is rotatably supported by a main bearing (not shown) in a cylinder block 1 that constitutes a part of the engine body for each cylinder. Each crank journal 3 has an axis O that coincides with the axis (rotation center) of the crankshaft 2 and constitutes a rotating shaft portion of the crankshaft 2.

  The crankshaft 2 includes a crankpin 4 that is eccentric from the axis O and is provided for each cylinder, a crank arm 4a that connects the crankpin 4 to the crank journal 3, and a crankpin 4 that is connected to the axis O. The counterweight 4b is disposed on the opposite side and mainly reduces the rotational primary vibration component of the piston motion. The crank arm 4a and the counterweight 4b are integrally formed in this embodiment.

  The piston 9 slidably fitted to the cylinder 10 formed for each cylinder and the crank pin 4 are mechanically linked by a plurality of link members, that is, the upper link 6 and the lower link 5. Has been. The upper end side of the upper link 6 is externally fitted to a piston pin 8 fixedly provided on the piston 9 so as to be relatively rotatable around the axis Oc. Further, the lower link side of the upper link 6 and the one main body 5a of the lower link 5 which is substantially divided into two halves are connected to each other around the axis Od by a connecting pin 7 through which both are inserted.

  The lower link 5 is configured by attaching two main bodies 5a and 5b so as to sandwich the crank pin 4. The lower link 5 is mounted so as to be relatively rotatable around the crank pin 4 and the axis Oe. Yes. The other lower link main body 5b, which is substantially divided into two parts, and the upper end side of the control link (third link) 11 are connected to each other around the axis Of by a connecting pin 12 through which both are inserted.

  The lower end side of the control link 11 is externally fitted and supported on a control shaft 13 having an eccentric cam portion 14 that is rotatably supported by the cylinder block 1 so as to be swingable around the axis Ob. That is, an eccentric cam portion 14 is rotatably provided on the outer periphery of the control shaft 13, and the axis Oa of the eccentric cam portion 14 is eccentric by a predetermined amount with respect to the axis Ob of the control shaft 13. The eccentric cam portion 14 is controlled to rotate by a compression ratio control actuator 16 via a worm gear 15 in accordance with the operating state of the engine and is held at an arbitrary rotation position. An electric motor is preferably used as the actuator 16. The motor is preferably an SRM (Switched Reluctance Motor) when operation under high temperature conditions is required, and an IPM (Interior Permanent Magnet) motor when high torque is required as the motor load.

  With such a configuration, as the crankshaft 2 rotates, the piston 9 moves up and down in the cylinder 10 via the crankpin 4, the lower link 5, the upper link 6 and the piston pin 8, and is connected to the lower link 5. The control link 11 swings with the swing axis Ob on the lower end side as a fulcrum.

  Further, the eccentric cam portion 14 is rotationally controlled by the compression ratio control actuator 16, so that the axis Ob of the control shaft 13 serving as the swing axis of the control link 11 is moved around the axis Oa of the eccentric cam portion 14. Rotation, that is, the swing center position Ob of the control link 11 moves relative to the engine body (and the crankshaft rotation center O). As a result, the stroke of the piston 9 changes, and the compression ratio of each cylinder of the engine is variably controlled. For reference, FIG. 5 schematically shows the postures of the three links 6, 5, 11 at the piston top dead center position. The left side of FIG. 5 is the high compression ratio position, and the right side of FIG. 5 is the low compression ratio position. Each link posture.

  The greatest feature of this compression ratio variable mechanism is that the top dead center position (combustion chamber volume) of the piston 9 can be changed by the angular position control of the control shaft 13, and the function as a so-called compression ratio variable mechanism is exhibited. In the present embodiment, the multi-link compression ratio variable mechanism is described, but the compression ratio variable mechanism is not limited to the multi-link type. For example, the actual compression ratio can be changed by changing the closing timing of the intake valve.

It is generally known that increasing the compression ratio improves the thermal efficiency of the engine. On the other hand, if the compression ratio is increased too much, knocking will occur, and therefore the compression ratio cannot be increased much, especially in the high load region. Therefore, in the engine 1 having the variable compression ratio mechanism, the target intake air amount (tQac) as shown in FIG. h) On the low load side where the h is small, the target compression ratio (CR0) is increased and the target intake air amount (tQac) By setting the target compression ratio (CR0) small on the high load side where h) is large, fuel consumption is improved without causing knocking.

  Returning to FIG. 1, the engine 1 further includes a turbocharger 45 in which an exhaust turbine 46 and a compressor 47 are arranged coaxially. The turbocharger 45 rotates the exhaust turbine 46 by using the energy of the exhaust, and drives the compressor 47 with this power to preload intake air. A normally closed waste gate valve 49 is provided in a passage 48 that bypasses the exhaust turbine 46. The waste gate valve 49 bypasses the exhaust when it exceeds the set boost pressure and releases it so that the boost pressure does not exceed the set boost pressure. A supercharging pressure sensor 39 for detecting the actual supercharging pressure is provided in the intake passage 23 upstream of the throttle valve 29.

Thus, when the turbocharger 45 is further provided for the engine 1 having the compression ratio variable mechanism, the method for obtaining the target compression ratio is different from that of the naturally aspirated engine as follows. That is, since the target intake air amount tQac at the time of natural intake is determined as shown in FIG. 6 according to the accelerator opening APO and the engine rotational speed Ne, the ratio between the atmospheric pressure Pa and the actual supercharging pressure rPb is The target intake air amount tQac during natural intake is corrected, that is, tQac h = tQac × Pa / rPb (1)
The supercharging pressure correction target intake air amount tQac which is the target intake air amount at the time of supercharging according to the formula h is calculated.

The turbocharger 45 is not provided, and in the natural intake state, the value of Pa / rPb, which is a fraction on the right side of the equation (1), becomes 1, and the boost pressure correction target intake air amount tQac h is equal to the target intake air amount tQac. On the other hand, since the actual supercharging pressure rPb is larger than the atmospheric pressure Pa when supercharging is performed by the turbocharger 45, the value of Pa / rPb that is a fraction on the right side of the equation (1) becomes a positive value smaller than 1. Boost pressure correction target intake air amount tQac h is smaller than the target intake air amount tQac. Thus, the supercharging pressure correction target intake air amount tQac at the time of supercharging The reason why h is set to be smaller than the target intake air amount tQac is that the intake air enters the combustion chamber 21 as much as the intake pressure is higher than the atmospheric pressure during supercharging than during natural intake. . That is, if an intake air amount exceeding the target intake air amount tQac flows into the combustion chamber 21, the pressure and temperature in the combustion chamber 21 will rise by that amount and knocking will not occur. Therefore, at the time of supercharging, the intake air amount (tQac) smaller than the target intake air amount tQac that is suitable for natural intake. By setting h), the actual intake air amount at the time of supercharging is made equal to the actual intake air amount at the time of natural intake, thereby preventing knocking.

Then, the boost pressure correction target intake air amount tQac obtained in this way is obtained. The target compression ratio basic value CR0 corresponding to h and the engine rotational speed Ne is determined as shown in FIG.

  The engine controller 35 to which the accelerator opening APO from the accelerator opening sensor 36, the rotation speed Ne from the engine rotation speed sensor 37, and the intake air flow rate signal from the air flow meter 38 are input, is based on these signals. The target value of the intake valve operating angle shown in FIG. 2, the base throttle valve opening shown in FIG. 3, the target compression ratio basic value CR0, the fuel injection amount, and the ignition timing shown in FIG. 7 are calculated. Then, the actuator of the variable lift mechanism 27 is driven so as to obtain the calculated intake valve operating angle target value, and the actuator 30 of the throttle valve 29 is driven so as to obtain the calculated base throttle valve opening, and the calculation is performed. The compression ratio actuator 16 is driven so that the target compression ratio basic value CR0 is obtained. Further, the actuator of the phase variable mechanism 28 is driven so that the intake valve 25 is opened at an optimal timing. Further, the fuel injection valve 33 and the spark plug 34 are controlled so that the calculated fuel injection amount and ignition timing are obtained.

Even if the compression ratio actuator 16 is controlled so as to obtain the target compression ratio basic value CR0 in the current control, knocking may occur when the vehicle is decelerated and re-accelerated from the current supercharging pressure state. It has been found that there is. The operation in this current control will be described with reference to FIG. 8. In FIG. 8, a deceleration operation for returning the accelerator pedal from the timing t1 in the middle of the high vehicle speed state and the steady running state to the timing t2 is performed. If the accelerator opening APO is maintained until the timing of t3, the accelerator pedal is depressed again from the timing of t3 to the timing of t5 to perform acceleration operation, and the accelerator opening APO is kept constant at the timing of t5, the throttle valve Opening TVO, boost pressure correction target intake air amount tQac h, how the actual boost pressure rPb, and the target compression ratio basic value CR0 change.

  In FIG. 8, it is assumed that the response delay of the compression ratio actuator 16 is sufficiently smaller than the response delay when the supercharging pressure decreases, and that the target compression ratio basic value CR0 and the actual compression ratio are substantially equal.

When the vehicle is decelerated at the timing of t1 in the current supercharging pressure state, particularly in a high supercharging pressure state as in a high load state, the target intake air amount tQac decreases, so the supercharging pressure correction intake air amount tQac h also decreases. At this time, the target compression ratio basic value CR0 is the boost pressure correction intake air amount tQac for improving fuel efficiency. It increases as h decreases.

  Since the turbocharger 45 has a large response delay with respect to the load change, it takes a considerable time until the decrease in the target intake air amount tQac appears in the actual supercharging pressure rPb. That is, the actual supercharging pressure rPb cannot be suddenly reduced when the vehicle is decelerated, but finally begins to decrease at a timing further delayed from the timing t2 when the deceleration is completed (see the fourth stage in FIG. 8). When the throttle valve 29 is opened more than the timing t4 in response to the reacceleration from t3, the actual supercharging pressure rPb is not sufficiently lowered at this time, so that the actual flow into the combustion chamber 21 is reduced. The amount of intake air becomes larger than when acceleration is performed in a low load state (see t4 and after in the third stage in FIG. 8).

  As a result, the pressure and temperature in the combustion chamber 21 rise unintentionally, and there is a concern about the occurrence of knocking. In this case, if the target compression ratio basic value CR0 can be reduced, even if the substantial intake air amount flowing into the combustion chamber 21 is large, it is possible to suppress an increase in pressure and temperature in the combustion chamber 21, and knocking is prevented. Occurrence can be avoided.

However, since the target compression ratio basic value CR0 is originally set in conformity with the steady operation, it takes into account that the actual boost pressure rPb decreases with a delay at the time of deceleration and re-acceleration from such a high boost pressure state. Not set up until then. For this reason, the target compression ratio basic value CR0 is determined from the timing t4 at which re-acceleration is performed regardless of the actual supercharging pressure rPb that is delayed after deceleration and re-acceleration from the high supercharging pressure state. Quantity tQac It decreases as h increases (see the bottom row in FIG. 8). In this way, since the target compression ratio basic value CR0 is set in conformity with the steady operation, the amount of intake air flowing into the combustion chamber 21 while the compression ratio remains high during deceleration reacceleration increases. There is a possibility that knocking may occur in the combustion chamber 21 due to high pressure and high temperature.

  Considering that the supercharging pressure may be high immediately before the deceleration reacceleration, the amount of intake air flowing into the combustion chamber 21 by throttle the throttle valve 29 even if the deceleration reacceleration is performed. Although it is possible to avoid knocking by restricting the torque, this method sacrifices the torque generated by the engine and deteriorates the acceleration performance.

  Therefore, in the present embodiment, it is determined in advance whether there is a possibility of knocking when the vehicle is decelerated and reaccelerated from the current boost pressure state, and the vehicle is decelerated from the current boost pressure state. When it is determined that there is a possibility of knocking when acceleration is performed, the vehicle is decelerated and re-accelerated from the high boost pressure state by correcting the target compression ratio (CR0) to the reduction side. Avoid knocking in case. At this time, the opening degree of the throttle valve 29 is maintained at an opening degree that secures the intake air amount required for acceleration and is not corrected. Alternatively, if the reduction of the compression ratio according to the present invention is not performed, the throttle valve 29 is corrected by restricting the throttle valve 29 by a predetermined amount even if it is not as much as the throttle of the intake air amount to avoid knocking. Can be suppressed on the safer side.

  This control performed by the engine controller 35 will be described in detail with reference to FIGS. 10, 11A, and 11B.

  FIG. 10 is a schematic diagram showing the function of the compression ratio control performed by the engine controller 35 as a block. The target intake air amount calculation means 51, the boost pressure correction target intake air amount calculation means 52, and the target compression ratio basic value calculation means. 53, knocking prior determination means 54, target compression ratio correction amount calculation means 55, and target compression ratio calculation means 56.

The target intake air amount calculation means 51 calculates a target intake air amount tQac based on the accelerator opening APO and the engine speed Ne. In the supercharging pressure correction target intake air amount calculation means 52, the supercharging pressure correction target intake air amount tQac is calculated from the target intake air amount tQac, the actual supercharging pressure rPb, and the atmospheric pressure Pa using the above equation (1). Calculate h.

In the knocking occurrence prior determination means 54, knocking occurs when the vehicle is decelerated and reaccelerated from the current boost pressure state based on the actual boost pressure rPb, the engine speed Ne, and the intake air temperature Tm. It is determined in advance whether there is a possibility. When it is determined by the knocking occurrence predetermining means 54 that there is a possibility of knocking when the vehicle is decelerated and reaccelerated from the current boost pressure state, the target compression ratio correction amount calculating means 55 Boost pressure correction target intake air amount tQac The compression ratio correction amount CRh0 is calculated based on h, the actual supercharging pressure rPb, and the engine speed Ne, and the target compression ratio calculation means 56 calculates the compression ratio correction amount CRh0 from the target compression ratio basic value CR0. The subtracted value is set as the target compression ratio tCR, that is,
tCR = CR0−CRh (2)
The target compression ratio tCR is calculated by the following formula (the target compression ratio is corrected to decrease).

  The engine controller 35 converts the target compression ratio tCR calculated in this way into a drive signal and outputs it to the compression ratio actuator 16, thereby achieving the target compression ratio tCR.

  FIG. 11A and FIG. 11B are flowcharts showing operations performed by the respective means 51 to 56 of FIG. 10, that is, a method for calculating the target compression ratio, and are executed at regular intervals (for example, every 10 ms).

  In step 1, the accelerator opening APO detected by the accelerator opening sensor 36, the engine rotation speed Ne detected by the engine rotation speed sensor 37, the actual boost pressure rPb detected by the boost pressure sensor 39, and the atmospheric pressure sensor 40. Is read in, and the intake air temperature Tm detected by the intake air temperature sensor 41 is read.

  In step 2, a target intake air amount tQac at the time of natural intake is calculated by searching a map having the contents shown in FIG. 6 from the accelerator opening APO and the engine speed Ne. As shown in FIG. 6, the target intake air amount tQac at the time of natural intake increases as the accelerator opening APO increases under a condition where the engine rotational speed Ne is constant, and the engine rotational speed increases under a condition where the accelerator opening APO is constant. As Ne increases, it increases.

  Here, the target intake air amount tQac during natural intake is a substitute value for the target boost pressure during supercharging. That is, if the target intake air amount tQac during natural intake during supercharging is obtained, the target supercharging pressure is obtained.

In step 3, using the actual supercharging pressure rPb detected by the supercharging pressure sensor 39 and the atmospheric pressure Pa detected by the atmospheric pressure sensor 40, the supercharging pressure correction target intake air amount according to the above equation (1). tQac Calculate h. As described above, at the time of supercharging, the supercharging pressure correction target intake air amount tQac The reason why h is made smaller than the target intake air amount tQac during natural intake is that the intake air enters the combustion chamber 21 as much as the intake pressure is higher than the atmospheric pressure during supercharging than during natural intake. In order to avoid this, the pressure and temperature in the combustion chamber 21 may rise to the extent that knocking will not occur.

In step 4, this boost pressure correction target intake air amount tQac A target compression ratio basic value CR0 is calculated by searching a map having the contents shown in FIG. 7 from h and the engine speed Ne. As shown in FIG. 7, the target compression ratio basic value CR0 is the boost pressure correction target intake air amount tQac under the condition that the engine speed Ne is constant. The smaller h is, the smaller it is. This is the boost pressure correction target intake air amount tQac. The target compression ratio basic value CR0 is increased to increase the thermal efficiency of the engine 1 at a low load when h becomes small, but the boost pressure correction target intake air amount tQac is increased. This is because knocking occurs when the target compression ratio basic value CR0 is increased even at a high load when h increases, and therefore, the target compression ratio basic value CR0 is decreased toward the higher load side to prevent the occurrence of knocking. . Also, the boost pressure correction target intake air amount tQac Under the condition that h is constant, the target compression ratio basic value CR0 does not depend much on the engine rotational speed Ne, and decreases as the engine rotational speed Ne increases only in the high rotational speed range.

  In step 5, knocking may occur when the vehicle is decelerated and re-accelerated from the current boost pressure state for each target compression ratio basic value using the actual boost pressure rPb and the engine speed Ne as parameters. From a map (this map is hereinafter referred to as “basic map”) that defines the boundary of a certain region (hereinafter, this region is simply referred to as “knock occurrence region”), it corresponds to the calculated target compression ratio basic value CR0. Select a base map. For example, assuming that the target compression ratio basic value CR0 is 10, 12, and 14 from the smaller side, and these are the first, second, and third target compression ratio basic values, each of the three target compression ratio basic values When the content of the basic map at is superimposed on FIG. 12, knocking occurs at the second compression ratio basic value (= 12) rather than the boundary A of the knocking occurrence region at the first target compression ratio basic value (= 10). The boundary B of the region where the knocking occurrence region has the basic value of the third target compression ratio (= 14) is better than the boundary B of the region where the knocking occurs at the second target compression ratio basic value (= 12). 12 is moving toward the lower right. That is, as the target compression ratio basic value CR0 increases, the knocking occurrence region expands to the side where the actual boost pressure rPb decreases and the engine speed Ne increases. This is because before the knocking has finished propagating through the entire unburned mixture by spark ignition, the unburned mixture (end gas) remaining in front of the flame is spontaneously ignited due to high temperature and pressure, causing an extreme pressure rise. This is because the phenomenon that occurs is that knocking tends to occur when the target compression ratio basic value is higher even if the actual boost pressure rPb and the engine rotational speed Ne are the same.

  Here, the target compression ratio basic value CR0 has three values of 10, 12, and 14 from the smaller side, but is not limited to this value. The minimum and maximum values of the target compression ratio basic value CR0 are determined in advance according to the engine specifications. Also, the numerical value of the target compression ratio basic value CR0 is not limited to two skips, but may be one skip. The number representing the boundary of the knocking region can be increased if there is a margin in the memory capacity, and can be decreased if there is no margin.

  In FIG. 12, for example, if the target compression ratio basic value CR0 calculated in step 4 of FIG. 11A is the first target compression ratio basic value (= 10), from the actual boost pressure rPb and the engine speed Ne. When the determined operating point is above the boundary A of the knocking occurrence region, knocking may occur when the vehicle is decelerated and reaccelerated from the current supercharging pressure state. On the other hand, when the operating point determined from the actual boost pressure rPb and the engine rotational speed Ne is below the boundary A of the knocking generation region, the vehicle is decelerated and reaccelerated from the current boost pressure state. There is no possibility that knocking will occur. Thus, the upper limit values of the actual boost pressure rPb and the engine rotation speed Ne that may cause knocking when the vehicle is decelerated and re-accelerated from the current boost pressure state at the boundary A of the knock generation region are determined. Has been decided. In other words, there is a possibility that knocking may occur when the actual boost pressure rPb and the engine rotational speed Ne when following the boundary A of the knock occurrence region are decelerated and re-accelerated from the current boost pressure state. The upper limit values of the actual supercharging pressure rPb and the engine rotational speed Ne. Therefore, selecting the basic map based on the target compression ratio may cause knocking when the vehicle is decelerated and re-accelerated from the current boost pressure state based on the target compression ratio basic value. This corresponds to determining upper limit values of the supercharging pressure rPb and the engine rotation speed Ne.

  In step 6, an intake air temperature correction amount H is calculated by searching a table having the contents shown in FIG. 13 from the intake air temperature Tm. In step 7, the basic map is corrected using the correction amount H.

  As shown in FIG. 13, the intake air temperature correction amount H is zero when the intake air temperature Tm is equal to the reference temperature T0, and increases as the intake air temperature Tm becomes higher than the reference temperature T0. Conversely, as the intake air temperature Tm becomes lower than the reference temperature T0, the intake air temperature correction amount H increases with a negative value. Here, the reference temperature T0 is the intake air temperature when the basic map is adapted.

  The correction of the basic map using the intake air temperature correction amount H will be described with reference to FIG. As shown in FIG. 14, if the boundary of the knocking occurrence region that is the content of the basic map is a solid line, the boundary of the knocking occurrence region indicated by the solid line is optimal when the intake air temperature Tm is the reference temperature T0. It will be. Therefore, when the intake air temperature Tm becomes higher than the reference temperature Tm0, the boundary of the knocking occurrence region moves away from the solid line and moves downward to the broken line, and the knocking occurrence region becomes larger than when the intake air temperature Tm is the reference temperature T0. This is because, even when the actual boost pressure rPb and the engine speed Ne are the same, when the intake air temperature Tm is higher than the reference temperature T0, the vehicle is decelerated and re-accelerated from the current boost pressure state than when the intake air temperature Tm is the reference temperature T0. This is because there is a high possibility that knocking will occur when this is performed. That is, the higher the intake air temperature Tm, the higher the possibility that knocking will occur because the end gas is exposed to a pressure and temperature that are higher in the combustion chamber 21. On the other hand, when the intake air temperature Tm becomes lower than the reference temperature T0, the boundary of the knocking occurrence region moves away from the solid line and moves upward to the one-dot chain line, and the knocking occurrence region is reduced as compared with when the intake air temperature Tm is the reference temperature T0. . This is because, even when the actual boost pressure rPb and the engine rotational speed Ne are the same, the intake air temperature Tm becomes the reference temperature when the vehicle is decelerated and re-accelerated from the current boost pressure state when the intake air temperature Tm is lower than the reference temperature T0. This is because the possibility of knocking is lower than when T0. That is, since the end gas is exposed to a pressure and temperature that are lower in the combustion chamber 21 when the intake air temperature Tm is lower, the possibility of knocking is reduced.

  As described above, since the boundary of the knocking occurrence region is affected by the intake air temperature Tm, even when the intake air temperature Tm deviates from the reference temperature T0, the vehicle is detected from the current supercharging pressure state using the boundary indicated by the solid line. When it is determined whether or not there is a possibility that knocking may occur when the deceleration reacceleration is performed, according to the actual supercharging pressure rPb and the engine speed Ne, the actual supercharging pressure state is actually exceeded. Knocking may occur when the vehicle is decelerated and re-accelerated, but knocking is not possible or when the vehicle is decelerated and re-accelerated from the current boost pressure state It is conceivable that it is erroneously determined that there is a possibility that knocking may occur even though there is no possibility that this will occur. Therefore, even when the intake air temperature Tm deviates from the reference temperature T0, it is erroneously determined whether or not knocking may occur when the vehicle is decelerated and re-accelerated from the current supercharging pressure state. Thus, the basic map is corrected using the correction amount H so that the occurrence of the occurrence of the error does not occur. For example, when the intake air temperature Tm is higher than the reference temperature T0, the boundary of the knocking generation region is corrected downward by the correction amount H with respect to the basic map. On the other hand, when the intake air temperature Tm is lower than the reference temperature T0, the boundary of the knocking generation region is corrected upward by the correction amount H with respect to the basic map.

  In FIG. 11B, in step 8, the actual boost pressure rPb and the engine speed Ne are determined on the basic map corrected by the intake air temperature correction amount H (this corrected basic map is hereinafter referred to as “corrected map”). It is checked whether or not the operating point (hereinafter, the operating point determined from the actual supercharging pressure rPb and the engine speed Ne is also simply referred to as “operating point”) is in the knocking occurrence region. If the operating point is above the boundary of the knocking generation area on the corrected map, the driving point is in the knocking generation area. Therefore, knocking may occur when the vehicle is decelerated and re-accelerated from the current boost pressure state. The process proceeds to steps 9, 10, 11, and 12.

  In this case, since the operating point moves in accordance with the actual boost pressure rPb and the engine rotational speed Ne, the state where the operating point is above the boundary of the knocking occurrence region on the corrected map continues for a predetermined time. Although the predetermined time cannot be generally specified, it depends on the actual supercharging pressure state before deceleration of the vehicle, the degree of deceleration and the deceleration time, the degree of reacceleration and the reacceleration time, and the like.

Steps 9 to 12 are portions for correcting the target compression ratio to be reduced. First, in step 9, the boost pressure correction target intake air amount tQac is set. 15 is searched from h and the actual boost pressure rPb to search the compression ratio correction amount basic value CRh0, and at step 10, the table from FIG. 16 is searched from the engine speed Ne. Thus, the rotation speed correction rate hn of the compression ratio correction amount basic value is calculated. In step 11, the rotation speed correction rate hn is multiplied by the compression ratio correction amount basic value CRh0, that is, CRh = CRh0 × hn (3)
The compression ratio correction amount CRh is calculated by the following formula. In step 12, the value obtained by subtracting the compression ratio correction amount CRh from the target compression ratio basic value CR0 is set as the target compression ratio tCR, that is, the target compression ratio tCR is calculated by the above equation (2).

As shown in FIG. 15, the compression ratio correction amount basic value CRh0 is a boost pressure correction target intake air amount tQac. h is a value that increases as the actual boost pressure rPb increases under a constant condition. This is because, as the actual boost pressure rPb is higher, when the vehicle is decelerated and re-accelerated from the current boost pressure state, the throttle valve opening increases due to the re-acceleration, the volume efficiency increases, and knocking may occur. Therefore, the compression ratio correction amount basic value CRh0 is increased so as to eliminate the possibility of knocking, so that the target compression ratio tCR when the vehicle is decelerated and re-accelerated from the current boost pressure state is set. This is to make it smaller.

As shown in FIG. 15, when the actual boost pressure rPb is high, the compression ratio correction amount basic value CRh0 is the boost pressure correction target intake air amount tQac. The value increases as h decreases. This is the boost pressure correction target intake air amount tQac. The smaller the h, the higher the compression ratio due to reacceleration when the vehicle is decelerated and reaccelerated from the current supercharging pressure state, and the possibility of knocking increases. Therefore, the compression ratio is reduced so that the possibility of knocking is eliminated. This is because the correction amount basic value CRh0 is increased, thereby reducing the target compression ratio tCR when the vehicle is decelerated and re-accelerated from the current supercharging pressure state.

  The characteristic of the compression ratio correction amount basic value CRh0 shown in FIG. 15 is that knocking may occur when the vehicle is decelerated and re-accelerated from the current boost pressure state under the condition that the engine rotational speed Ne is the reference rotational speed N0. It is a characteristic that is adapted so that there is no property. For this reason, the compression ratio correction amount basic value CRh0 may be maintained under the condition that the engine rotation speed Ne is the reference rotation speed N0. Therefore, as shown in FIG. 16, the rotation speed correction is performed when the engine rotation speed Ne is the reference rotation speed N0. The rate hn is 1.0. At this time, the compression ratio correction amount CRh matches the compression ratio correction amount basic value CRh0 from the above equation (3).

  On the other hand, if the engine rotational speed Ne is smaller than the reference rotational speed N0, knocking may occur when the vehicle is decelerated and re-accelerated from the current boost pressure state by the amount corresponding to the decrease in the engine rotational speed Ne. Get higher. This is because the lower the rotational speed, the longer the time during which the end gas is exposed to high pressure and temperature in the combustion chamber 21 and the higher the probability that knocking will occur. For this reason, when the engine rotational speed Ne is smaller than the reference rotational speed N0, the rotational speed correction rate hn is set to a value larger than 1.0 as shown in FIG. 16, whereby the compression ratio correction amount CRh is calculated from the above equation (2). Can be made larger than the compression ratio correction amount basic value CRh0, so that knocking may occur even when the vehicle is decelerated and re-accelerated from the current boost pressure state in a region where the engine rotational speed Ne is smaller than the reference rotational speed N0. Try not to have sex.

  On the other hand, if the engine rotational speed Ne becomes higher than the reference rotational speed N0, knocking may occur when the vehicle is decelerated and re-accelerated from the current boost pressure state by the amount corresponding to the increase in the rotational speed. Lower. This is because the higher the rotation speed, the shorter the time during which the end gas is exposed to high pressure and temperature in the combustion chamber 21, and the lower the probability of knocking. Therefore, when the engine rotational speed Ne is larger than the reference rotational speed N0, the rotational speed correction rate hn is set to a positive value smaller than 1.0 as shown in FIG. By making CRh larger than the compression ratio correction amount basic value CRh0, the compression ratio is increased when the vehicle is decelerated and re-accelerated from the current boost pressure state in the region where the engine rotational speed Ne is larger than the reference rotational speed N0. The fuel efficiency is improved by maintaining the thermal efficiency of the engine 1.

  After the operating point stays above the boundary of the knocking region for a while and then moves below the boundary of the knocking region, the operating point has moved out of the knocking region, so knocking may no longer occur. In step 11 of FIG. 11B, the process proceeds to step 13 and the target compression ratio basic value CR0 is set as the target compression ratio tCR as it is.

  In addition, if the operating point is originally below the boundary of the knocking generation region, the driving point is not in the knocking generation region, so that knocking may occur when the vehicle is decelerated and reaccelerated from the current boost pressure state. 11B, the process proceeds from step 8 to step 13 to directly set the target compression ratio basic value CR0 as the target compression ratio tCR.

  The target compression ratio tCR calculated in this way is converted into a drive signal in a flow (not shown) and output to the compression ratio actuator 16.

The operation of this embodiment will be described with reference to FIG. 9. FIG. 9 shows that the throttle valve opening TVO and the boost pressure correction target intake air amount tQac are the same as in FIG. h, how the actual boost pressure rPb, and the target compression ratio tCR change. What is different from FIG. 8 is the target compression ratio tCR.

In the present embodiment, for example, it is determined that knocking may occur when the vehicle is decelerated and reaccelerated from the current supercharging pressure state from the timing t11 to the timing t12. When it is determined that there is a possibility of knocking when the vehicle is decelerated and reaccelerated from the current boost pressure state, the boost pressure correction target intake air amount tQac in the third stage of FIG. 9 is determined. The compression ratio correction amount CRh is calculated as a positive value from h, the actual boost pressure rPb in the fourth stage in FIG. 9 and the engine speed Ne at that time, and this positive value is calculated from the target compression ratio basic value CR0. A value obtained by subtracting the compression ratio correction amount CRh is calculated as the target compression ratio tCR.

  As a result, the target compression ratio tCR is smaller than the target compression ratio basic value CR0 from the timing t11 to the timing t12 (see the one-dot chain line in the lowermost stage in FIG. 9). That is, when the throttle valve 29 is opened by deceleration and reacceleration while the actual supercharging pressure rPb is high, even if the decrease in the actual supercharging pressure rPb is delayed due to the response delay of the turbocharger 45, the delay is commensurate with the delay. Thus, it is possible to reduce the compression ratio, thereby preventing knocking when the vehicle is decelerated and re-accelerated from a state where the actual supercharging pressure rPb is high.

  Thus, according to the present embodiment (the invention described in claim 1), the compression ratio variable mechanism, the target compression ratio setting means for setting the target compression ratio (CR0) (see step 3 in FIG. 11A), The control means (35) for controlling the compression ratio variable mechanism so as to achieve the set target compression ratio (CR0), the turbocharger 45, the lift variable mechanism 27 (intake air amount adjusting means), the lift In an engine equipped with an intake air amount control means (35) for controlling the intake air amount according to operating conditions using the variable mechanism 27, when the vehicle is decelerated and re-accelerated from the current supercharging pressure state. When knocking occurrence predetermination means (see step 8 of FIG. 11B) for preliminarily determining whether knocking may occur or not, and when the vehicle is decelerated and reaccelerated from the current supercharging pressure state by this determination means To knockin When it is determined that there is a possibility of occurrence of the target compression ratio (CR0), the target compression ratio reduction correction means (see steps 9 to 12 in FIG. 11B) for correcting the target compression ratio (CR0) to the reduction side. When the throttle valve 29 is opened by deceleration and reacceleration while the actual supercharging pressure rPb is high, even if the decrease in the actual supercharging pressure rPb is delayed due to the response delay of the turbocharger 45, the delay is commensurate with the delay. The compression ratio can be lowered, and knocking can be avoided when the vehicle is decelerated and reaccelerated while the actual supercharging pressure rPb is high.

According to the present embodiment (the invention described in claim 2), the target compression ratio setting means calculates the target intake air amount calculation means for calculating the target intake air amount tQac during natural intake based on the operating conditions of the engine (see FIG. 11A, step 2 (see FIG. 6) and the ratio of the atmospheric pressure Pa to the actual supercharging pressure rPb, the target intake air amount tQac at the time of natural intake is corrected, and the supercharging that is the target intake air amount at the time of supercharging Pressure correction target intake air amount tQac A boost pressure correction target intake air amount calculating means for calculating h (see step 3 in FIG. 11A), and this boost pressure correction target intake air amount tQac. Since it comprises means for setting the target boost pressure (CR0) based on h (see step 4 in FIG. 11A, FIG. 7), the boost pressure correction target intake air amount tQac during supercharging. h becomes smaller than the target intake air amount tQac at the time of natural intake, thereby preventing knocking due to an intake air amount larger than the target intake air amount tQac at the time of natural intake flowing into the combustion chamber at the time of supercharging it can.

According to this embodiment (the invention according to claim 3), the target compression ratio reduction correction means is a boost pressure correction target intake air amount tQac. The compression ratio correction amount calculating means (see step 9 in FIG. 11B, FIG. 15) for calculating the compression ratio correction amount (CRh0) based on h and the actual boost pressure rPb, and the compression ratio from the target compression ratio (CR0). Since the value obtained by subtracting the correction amount (CRh0) is used again as a target compression ratio (see step 12 in FIG. 11B), the boost pressure correction target intake air amount tQac Regardless of h or the actual boost pressure rPb, it is possible to avoid the occurrence of knocking when the vehicle is decelerated and re-accelerated from the current boost pressure state.

  According to the present embodiment (the invention described in claim 4), the compression ratio correction amount (CRh0) is increased as the actual boost pressure rPb is higher (see FIG. 15). Regardless of the current actual supercharging pressure rPb, knocking can be avoided when the vehicle is decelerated and reaccelerated from the current supercharging pressure state.

According to the present embodiment (the invention described in claim 5), the compression ratio correction amount (CRh0) is set to the boost pressure correction target intake air amount tQac. The smaller h is, the larger the value is (see FIG. 15). Therefore, the current boost pressure correction target intake air amount tQac before the vehicle is decelerated and re-accelerated. Regardless of the size of h, knocking can be avoided when the vehicle is decelerated and reaccelerated from the current supercharging pressure state.

  According to the present embodiment (the invention described in claim 6), since the compression ratio correction amount (CRh0) is corrected by the engine rotational speed Ne (see steps 10 and 11 in FIG. 11B), before the vehicle is decelerated and re-accelerated. In particular, it is on the low rotational speed side, and it is possible to avoid the occurrence of knocking when the vehicle is decelerated and re-accelerated from the current supercharging pressure state regardless of the engine rotational speed Ne in this state.

  According to the present embodiment (the invention described in claim 7), the knocking occurrence predetermination means can avoid the occurrence of knocking when deceleration reacceleration is performed from the current supercharging pressure state. An actual supercharging pressure / engine speed upper limit determining means (see step 5 in FIG. 11A) for determining each upper limit value of the supercharging pressure and engine speed for each target compression ratio (CR0) is provided. When the pressure rPb and the engine rotational speed Ne are higher than the actual supercharging pressure / engine rotational speed upper limit values determined by the actual supercharging pressure / engine rotational speed upper limit determining means, the current supercharging pressure state is exceeded. Since it is determined that knocking may occur when the vehicle is decelerated and re-accelerated (see step 8 in FIG. 11B), knocking occurs when the vehicle is decelerated and re-accelerated from the current boost pressure state. Can occur It can be performed of determining whether there is a sex easily.

  According to the present embodiment (the invention described in claim 10), the intake temperature sensor 41 (temperature detection means) is provided, and the knocking occurrence region (deceleration reacceleration of the vehicle from the current supercharging pressure state) based on the intake air temperature Tm. If the vehicle is decelerated and re-accelerated from the current boost pressure state, whether or not knocking may occur is corrected. Can be accurately determined regardless of the intake air temperature Tm.

  According to the present embodiment (the invention described in claim 13), when the target compression ratio (CR0) is corrected to the reduction side, the throttle valve opening TVO is not corrected. That is, when the vehicle is decelerated and re-accelerated from the current supercharging pressure state, the throttle valve 29 is not throttled to limit the intake air amount, so that the acceleration performance is deteriorated without sacrificing torque. Can be suppressed.

  In the embodiment, a case has been described in which the amount of intake air flowing into the combustion chamber 21 is controlled by controlling the lift amount and operating angle of the intake valve 25 and the phase of the lift center angle of the intake valve 25 according to operating conditions. This is not the only case. In an engine that does not include the variable lift mechanism 27 and the variable phase mechanism 28, the present invention is also applicable to the case where the intake air amount flowing into the combustion chamber 21 is controlled by the throttle valve opening.

In the embodiment, the boost pressure correction target intake air amount tQac is based on the target intake air amount tQac. h is calculated, and the boost pressure correction target intake air amount tQac is calculated. As described above, the target compression ratio basic value CR0 is calculated based on h, but the boost pressure correction target engine torque tTeng is calculated based on the target engine torque tTeng. h (= tTeng × Pa / rPb) is calculated, and the boost pressure correction target engine torque tTeng is calculated. The target compression ratio basic value CR0 may be calculated based on h.

  In the embodiment, the case where the actual supercharging pressure rPb is detected by the supercharging pressure sensor 39 has been described. However, known techniques for estimating the actual supercharging pressure (Japanese Patent Laid-Open Nos. 2005-155506, 2001-90543, Therefore, the actual supercharging pressure may be estimated using this known technique.

  In the embodiment, the case where the boundary of the knocking occurrence region (the region where knocking may occur when the vehicle is decelerated and reaccelerated from the current boost pressure state) is corrected based on the intake air temperature Tm has been described. However, this is not the only case. The boundary of the knocking occurrence region (region where knocking may occur when the vehicle is decelerated and reaccelerated from the current supercharging pressure state) may be corrected based on the coolant temperature.

1 Engine 27 Variable lift mechanism (intake air amount adjusting means)
29 Throttle valve (throttle valve device)
35 Engine controller 41 Intake air temperature sensor (temperature detection means)
45 turbocharger

Claims (13)

A variable compression ratio mechanism capable of changing the compression ratio of the engine;
Target compression ratio setting means for setting a target compression ratio;
Control means for controlling the variable compression ratio mechanism to achieve the set target compression ratio;
A turbocharger driven by exhaust,
An intake air amount adjusting means for adjusting the intake air amount;
In an engine provided with intake air amount control means for controlling the intake air amount according to operating conditions using the intake air amount adjusting means,
Knocking occurrence predetermining means for determining in advance whether or not knocking may occur when the vehicle is decelerated and reaccelerated from the current supercharging pressure state;
The target compression ratio reduction correction that corrects the target compression ratio to the reduction side when it is determined by this determination means that knocking may occur when the vehicle is decelerated and reaccelerated from the current boost pressure state. And an engine control device. The target compression ratio setting means includes
A target intake air amount calculating means for calculating a target intake air amount during natural intake based on engine operating conditions;
A boost pressure correction target that calculates the boost pressure correction target intake air amount that is the target intake air amount at the time of supercharging by correcting the target intake air amount at the time of natural intake by the ratio of the atmospheric pressure and the actual boost pressure Intake air amount calculating means;
2. The engine control device according to claim 1, further comprising means for setting the target boost pressure based on the boost pressure correction target intake air amount. The target compression ratio reduction correction means is
Compression ratio correction amount calculating means for calculating a compression ratio correction amount based on the supercharging pressure correction target intake air amount and the actual supercharging pressure;
3. The engine control apparatus according to claim 2, further comprising means for renewing a value obtained by subtracting the compression ratio correction amount from the target compression ratio as the target compression ratio.   4. The engine control device according to claim 3, wherein the compression ratio correction amount is increased as the actual boost pressure is higher.   4. The engine control device according to claim 3, wherein the compression ratio correction amount is increased as the supercharging pressure correction target intake air amount is smaller.   The engine control apparatus according to claim 2, wherein the compression ratio correction amount is corrected by an engine speed. The knocking occurrence prior determination means is
Actual supercharging for determining each upper limit value of the actual supercharging pressure and engine speed that can avoid the occurrence of knocking when deceleration and re-acceleration is performed from the current supercharging pressure state for each target compression ratio Pressure / engine speed upper limit determination means,
If the current actual boost pressure and engine speed are above the upper limits of the actual boost pressure and engine speed determined by the actual boost pressure / engine speed upper limit determining means, The engine control device according to claim 1, wherein it is determined that knocking may occur when the vehicle is decelerated and reaccelerated from the supply pressure state.   The actual boost pressure / engine rotational speed upper limit determining means determines a boundary of a region where knocking may occur using the actual boost pressure and the engine rotational speed as parameters based on the target compression ratio. The engine control device according to claim 7, wherein the engine control device is a boundary determination unit.   9. The engine control apparatus according to claim 8, wherein the knocking region boundary determination means is a map that defines a boundary of a region where knocking may occur for each target compression ratio.   There is provided temperature detecting means for detecting the intake air temperature or the coolant temperature, and knocking may occur when the vehicle is decelerated and re-accelerated from the current supercharging pressure state based on the intake air temperature or the coolant temperature. The engine control device according to claim 9, wherein a boundary of a certain region is corrected.   2. The engine control device according to claim 1, wherein the intake air amount adjusting means is a variable lift mechanism capable of continuously increasing or decreasing a lift amount and an operating angle of the intake valve.   The engine control device according to claim 1, wherein the intake air amount adjusting means is a throttle valve device capable of adjusting an opening of a throttle valve.   13. The engine control device according to claim 12, wherein when the target compression ratio is corrected to the reduction side, the opening degree of the throttle valve is not corrected.

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