JP6311363B2 - Control device for internal combustion engine - Google Patents

Description

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

  As a technique related to control of an onboard internal combustion engine, so-called torque base control is known in which driving of various actuators is controlled based on a required torque requested by a driver. In torque-based control, the required torque is calculated based on the accelerator operation amount by the driver and the operating state of the internal combustion engine at that time, and the target torque is calculated by adding engine loss such as pump loss and friction loss to the required torque. Is calculated. In order to realize the target torque, the operation of various actuators such as a throttle adjustment device, an injection device, and an ignition device is controlled.

  Further, for example, Patent Document 1 discloses a technique for adjusting the amount of air in the cylinder and the EGR rate by cooperating a plurality of actuators. Specifically, for this technique, a correction coefficient for correcting the influence of EGR on the torque is calculated based on the target EGR rate and the actual value or estimated value of the current air amount, and the target is calculated using the correction coefficient. The target air amount is calculated from the value obtained by correcting the torque, and the operation of each of the plurality of actuators is controlled based on the target air amount and the target EGR rate.

Japanese Patent No. 4251228

  By the way, in the configuration using the external EGR device, even if the EGR valve is operated to introduce an amount of EGR gas corresponding to the target EGR rate, the EGR gas corresponding to the change in the opening degree of the EGR valve is actually in the internal combustion engine. It takes time for gas transportation or the like to be sucked into the cylinder. That is, a delay in transient response occurs with respect to the introduction of EGR gas. In this regard, the above-described prior art is intended to perform torque control so as not to be affected by EGR, but it is considered that there is still room for improvement.

  The main object of the present invention is to provide a control device for an internal combustion engine that can achieve high accuracy and stabilization of torque control when EGR gas is introduced.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  The control device for an internal combustion engine in the present invention is provided in a torque control means for controlling torque generated in the internal combustion engine (10) based on a required torque determined according to a user's request, and an EGR pipe (36). And an EGR control means for driving the EGR valve (37) and controlling the flow rate of the EGR gas recirculated from the exhaust side to the intake side via the EGR pipe. And a target EGR rate setting means for setting a target EGR rate that is a target value of the EGR rate in the internal combustion engine, and a delay in response until the EGR gas that has passed through the EGR valve flows into the cylinder of the internal combustion engine. Based on the deviation between the response limiting means for limiting the response of the target EGR rate based on the response, the target EGR rate for which the response limiting is limited by the response limiting means, and the target EGR rate for which the response is not limited, the introduction of EGR gas Correction parameter calculation means for calculating a correction parameter for correcting the influence on the accompanying torque, and torque correction means for correcting the required torque with the correction parameter calculated by the correction parameter calculation means. Features.

  In the above configuration, when the required torque is corrected, a correction parameter for torque correction is calculated based on the deviation between the target EGR rate with a response limit and the target EGR rate without a response limit. Torque control can be carried out in consideration of the change in torque loss and the change in combustion state. In this case, when the target EGR rate changes (transient), torque correction is performed in consideration of the response delay of the actual EGR rate with respect to the change in the target EGR rate. For this reason, it is possible to appropriately cope with the transient response when the EGR gas is introduced. As described above, high accuracy and stabilization of torque control at the time of introduction of EGR gas can be realized.

The block diagram which shows the outline of the engine control system in embodiment of invention. The functional block diagram which shows the outline | summary of the engine control by a torque base. The functional block diagram which shows the outline | summary of the control regarding EGR at the time of introduction | transduction of EGR gas. The time chart which shows the delay of the actual EGR rate with respect to a target EGR rate. The figure which shows the relationship between an EGR rate deviation and EGR efficiency. The figure which shows the relationship between an EGR rate and a cooling loss in an engine heat account. The flowchart which shows the process sequence of air quantity control. The flowchart which shows the process sequence of EGR control.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In this embodiment, a multi-cylinder four-cycle gasoline engine (internal combustion engine) mounted on a vehicle is to be controlled, and electronic control of various actuators in the engine is performed. First, the overall schematic configuration of the engine control system will be described with reference to FIG.

  In the engine 10 shown in FIG. 1, an air flow meter 12 for detecting an intake air amount is provided upstream of the intake pipe 11. A throttle valve 14 whose opening degree is adjusted by a throttle actuator 13 such as a DC motor is provided on the downstream side of the air flow meter 12. The opening (throttle opening) of the throttle valve 14 is detected by a throttle opening sensor 15 built in the throttle actuator 13. A surge tank 16 is provided on the downstream side of the throttle valve 14, and an intake manifold 17 that is connected to an intake port of each cylinder is attached to the surge tank 16.

  The intake port and the exhaust port of the engine 10 are respectively provided with an intake valve and an exhaust valve (both not shown). The engine 10 is provided with an intake side valve mechanism 21 that changes the opening / closing timing of the intake valve and an exhaust side valve mechanism 22 that changes the opening / closing timing of the exhaust valve. Further, the engine 10 is provided with a fuel injection valve 23 and a spark plug 24 for each cylinder.

  An exhaust manifold 25 is connected to the exhaust port of the engine 10, and an exhaust pipe 26 is connected to a collecting portion of the exhaust manifold 25. The exhaust pipe 26 is provided with a catalyst 28 for purifying harmful components in the exhaust. In the present embodiment, a three-way catalyst that purifies three components of CO, HC, and NOx is used as the catalyst 28. An air-fuel ratio sensor 29 that detects the air-fuel ratio (oxygen concentration) of the air-fuel mixture is provided on the upstream side of the catalyst 28 as a detection target.

  A turbocharger 30 serving as a supercharger is provided between the intake pipe 11 and the exhaust pipe 26. The turbocharger 30 includes an intake compressor 31 disposed on the upstream side of the throttle valve 14 in the intake pipe 11, an exhaust turbine 32 disposed on the upstream side of the catalyst 28 in the exhaust pipe 26, and the intake compressor 31 and the exhaust turbine 32. The rotating shaft 33 to be connected is provided. In the turbocharger 30, when the exhaust turbine 32 is rotated by the exhaust flowing through the exhaust pipe 26, the intake compressor 31 is rotated with the rotation of the exhaust turbine 32, and the intake air is compressed by the centrifugal force generated by the rotation of the intake compressor 31. (Supercharged).

  Further, the intake pipe 11 is provided with an intercooler 34 as a heat exchanger for cooling the supercharged intake air on the downstream side of the throttle valve 14, and the intake air is cooled by the intercooler 34. A reduction in air charging efficiency is suppressed. The intercooler 34 is, for example, a water-cooled intake air cooling means. In the present embodiment, the intercooler 34 is provided integrally with the surge tank 16, but the intercooler 34 may be provided upstream of the surge tank 16 or upstream of the throttle valve 14.

  Further, the engine 10 is provided with an external EGR device 35 that introduces a part of the exhaust gas as EGR gas to the intake side. The EGR device 35 includes an EGR pipe 36 that connects the intake pipe 11 and the exhaust pipe 26, an electromagnetically driven EGR valve 37 that adjusts the amount of EGR gas flowing through the EGR pipe 36, and an EGR cooler 38 that cools the EGR gas. And have. The EGR cooler 38 is, for example, a water-cooled EGR cooling means. The EGR pipe 36 is provided so as to connect the downstream side of the exhaust turbine 32 (for example, the downstream side of the catalyst 28) in the exhaust pipe 26 and the upstream side of the intake compressor 31 in the intake pipe 11, and thereby the so-called LPL. A system (low pressure loop system) EGR system is constructed.

  In addition, the present system includes a crank angle sensor 41 that outputs a crank angle signal for each predetermined crank angle of the engine 10, a water temperature sensor 42 that detects the coolant temperature of the engine 10, and an accelerator sensor 43 that detects the amount of accelerator operation by the driver. Various sensors such as are provided.

  The ECU 50 is composed mainly of a microcomputer (hereinafter referred to as a microcomputer 51) composed of a CPU, a ROM, a RAM, and the like as well known, and executes various control programs stored in the ROM, thereby performing various controls of the engine 10. carry out. Specifically, the microcomputer 51 inputs detection signals and the like from the various sensors described above, and based on the input detection signals and the like, the throttle valve 14, the fuel injection valve 23, the spark plug 24, the EGR valve 37, and the like. Control the drive.

  In the present embodiment, engine control based on torque is performed, and the microcomputer 51 controls the air amount by adjusting the opening of the throttle valve 14 or the fuel injection amount in accordance with the required torque requested by the driver (user). Control, ignition timing control, and EGR rate control are appropriately implemented. Thereby, the torque generated by the engine 10 is controlled. In this case, in particular, the microcomputer 51 calculates a target throttle opening that is an air amount control parameter as an air amount control function, and controls the intake air amount of the engine 10 based on the target throttle opening. Further, the microcomputer 51 controls the flow rate of the EGR gas recirculated from the exhaust side to the intake side based on the engine operating state as an EGR control function. In addition to the above, the torque-based control includes control of the opening / closing timing of the intake valve and the exhaust valve, but the description is omitted in this embodiment. In the present embodiment, the microcomputer 51 constitutes torque control means and EGR control means.

  FIG. 2 is a functional block diagram showing an outline of engine control based on torque. Each function shown in FIG. 2 is realized by the microcomputer 51 of the ECU 50.

  In FIG. 2, the required torque of the engine 10 is calculated based on, for example, the engine rotational speed NE and the accelerator operation amount. The torque correction unit M11 performs various corrections on the required torque to calculate the target torque. In the torque correction unit M11, the target torque is calculated by correcting the engine loss and various kinds of efficiency. As the engine loss correction, for example, torque correction based on pump loss and friction loss is performed. As the efficiency correction, ignition efficiency correction based on the ignition timing and air-fuel ratio efficiency correction based on the actual air-fuel ratio are performed.

  Here, regarding the ignition timing, the ignition efficiency calculation unit M12 calculates a retard amount of the actual ignition timing with respect to MBT, and calculates an ignition efficiency E1 based on the retard amount. As for the actual air-fuel ratio, the air-fuel ratio efficiency calculation unit M13 calculates the air-fuel ratio efficiency E2 based on the target air-fuel ratio each time. The ignition efficiency E1 is calculated so as to be smaller as the retard amount of the actual ignition timing with respect to MBT is larger, and the air-fuel ratio efficiency E2 is richer than a predetermined rich air-fuel ratio as a peak, and The leaner the value, the smaller the value. Note that the smaller the efficiency, the smaller the generated torque in the engine 10. Then, the torque correction unit M11 divides the required torque by the multiplication value of the ignition efficiency E1 and the air-fuel ratio efficiency E2, and calculates the target torque as a result.

  The target air amount calculation unit M14 calculates a target charge air amount based on the target torque using a predetermined charge air amount model. The target opening calculation unit M15 calculates a target throttle opening based on a target charging air amount and an estimated charging air amount calculated by a later-described charging air amount estimation unit M17 using a predetermined intake system model. . Further, the throttle control unit M16 calculates a control duty for driving the throttle actuator 13 based on the target throttle opening and the actual throttle opening detected by the throttle opening sensor 15. The throttle actuator 13 is driven by this control duty to adjust the throttle opening, and the air amount is controlled accordingly.

  The filling air amount estimation unit M17 estimates the filling air amount based on the actual throttle opening and the actual intake air amount detected by the air flow meter 12, using a predetermined intake system model.

  In addition, the ignition timing calculation unit M18 calculates the ignition timing based on the estimated charge air amount and the engine speed NE. Based on this ignition timing, the spark plug 24 is driven to ignite. The injection amount calculation unit M19 calculates the fuel injection amount based on the estimated charge air amount, the target air-fuel ratio, and the actual air-fuel ratio detected by the air-fuel ratio sensor 29. The injection amount calculation unit M19 calculates the fuel injection amount by performing air-fuel ratio feedback control so that the actual air-fuel ratio matches the target air-fuel ratio. The fuel injection valve 23 is driven based on this fuel injection amount.

  In the system according to the present embodiment, in the engine control based on the torque, the required torque efficiency is further corrected based on the EGR rate of the external EGR device 35, and the air amount control that reflects the EGR is performed. The details will be described below.

  FIG. 3 is a functional block diagram showing an outline of EGR-related control at the time of introduction of EGR gas. FIG. 3 shows the EGR control unit M20 as a main part, and the torque correction unit M11, the target air amount calculation unit M14, and the target opening calculation unit M15 in the figure are the same as those shown in FIG. . Each function shown in FIG. 3 is realized by the microcomputer 51 of the ECU 50 as in FIG.

  In the EGR control unit M20 of FIG. 3, the target EGR rate calculation unit M21 calculates the target EGR rate based on the air amount and the engine rotational speed NE that are load parameters. In the present embodiment, the target charge air amount calculated by the target air amount calculation unit M14 is used as a load parameter. Specifically, the target EGR rate is calculated based on the target charge air amount and the engine rotational speed NE using a map that defines the relationship among the target charge air amount, the engine rotational speed NE, and the target EGR rate.

  The response limiting unit M22 limits the response of the target EGR rate based on a response delay until the EGR gas that has passed through the EGR valve 37 flows into the engine cylinder. At this time, response restriction is performed on the target EGR rate using an air model that simulates the behavior related to in-cylinder inflow of EGR gas, and the actual EGR rate at the time when EGR gas flows into the in-cylinder is calculated. Thereby, the EGR rate in accordance with the actual change is calculated. The air model was constructed based on a response delay from when the EGR valve 37 opening degree change was commanded to when the EGR gas increased or decreased by the EGR opening change was sucked into the cylinder (combustion chamber). Therefore, the response delay of the EGR valve 37 and the transport delay of the EGR gas in the EGR pipe 36 and the intake pipe 11 are taken into consideration. In this embodiment, the air model is expressed as a first-order lag model with a time constant T [s] and a dead time L [s], and the transfer function is constructed as “(1 / Ts + 1) e ^ −Ls”.

  When the target EGR rate is response-limited, a delay is given when a transient change occurs in the target EGR rate. This will be described with reference to FIG. In FIG. 4, the target EGR rate without response limitation is T1, and the target EGR rate with response limitation is T2. As shown in FIG. 4, when the target EGR rate increases, T1 increases and changes stepwise, whereas T2 increases and changes with a predetermined delay due to response limitation. Further, when the target EGR rate decreases, T1 decreases and changes stepwise, whereas T2 decreases and changes with a predetermined delay due to response limitation.

  Then, in the EGR efficiency calculation unit M23, the deviation between the target EGR rate whose response is limited by the response limiting unit M22 and the target EGR rate where the response is not limited (= target EGR rate with response limitation−target EGR rate without response limitation) ) And the EGR efficiency E3 is calculated based on the EGR rate deviation. In FIG. 3, the EGR efficiency calculation unit M23 calculates the EGR efficiency E3 based on the deviation (T2−T1) between the target EGR rate without response limitation T1 and the target EGR rate with response limitation T2. . The EGR efficiency E3 is a correction parameter for correcting the influence on the torque accompanying the introduction of EGR gas. In the present embodiment, the EGR efficiency calculation unit M23 corresponds to “correction parameter calculation means”.

  Specifically, the EGR efficiency calculation unit M23 calculates the EGR efficiency E3 using the relationship shown in FIG. In FIG. 5, when the EGR rate deviation is 0 or in the vicinity of 0, the EGR efficiency E3 is set to 1, and the EGR efficiency E3 is reduced as the absolute value of the EGR rate deviation increases (that is, the torque increase correction amount is increased). Such a relationship has been established.

  More specifically, when the EGR rate deviation is negative, that is, when “T2 <T1” is obtained by increasing the target EGR rate as indicated by X1 in FIG. 4, the actual EGR rate with respect to the target value. It is considered that the cooling loss in the engine 10 increases due to the decrease in EGR, and therefore the EGR efficiency E3 is lowered. That is, the EGR efficiency E3 is calculated by reflecting the increase in the cooling loss of the engine 10. FIG. 6 shows the relationship between the EGR rate and the cooling loss in the heat account of the engine 10. According to FIG. 6, for example, when the EGR rate is 0% and 25%, it can be confirmed that the cooling loss is smaller at 25%. That is, it can be seen that the greater the degree of decrease in the actual EGR rate with respect to the target value, the greater the decrease in cooling loss.

  On the other hand, when the EGR rate deviation is positive, that is, when the target EGR rate decreases and changes as shown by X2 in FIG. 4 so that “T2> T1”, the actual EGR rate with respect to the target value It is considered that the combustion state deteriorates due to the increase in the EGR, and therefore the EGR efficiency E3 is lowered. That is, the EGR efficiency E3 is calculated by reflecting that the combustion of the engine 10 deteriorates.

  In FIG. 5, the slope (change rate) of the EGR efficiency on the vertical axis with respect to the EGR rate deviation on the horizontal axis may be different between the positive and negative cases of the EGR rate deviation. The slope may be larger than when the is negative, or vice versa. It is also possible to calculate the EGR efficiency E3 based on the target EGR rate. In this case, the EGR efficiency E3 may be set to a smaller value as the target EGR rate is larger.

  The EGR efficiency calculated by the EGR efficiency calculation unit M23 is used for torque correction by the torque correction unit M11. That is, the torque correction unit M11 divides the required torque by the multiplication value of the ignition efficiency E1, the air-fuel ratio efficiency E2, and the EGR efficiency E3, and calculates the target torque as a result. As a result, appropriate air amount control can be performed while taking into account the effects of ignition timing, air-fuel ratio, and EGR on torque.

  Further, the target EGR opening degree calculation unit M24 calculates a target EGR opening degree that is a target value of the opening degree of the EGR valve 37, based on the target EGR rate. Specifically, the target EGR opening is calculated based on the target EGR rate using a map that defines the relationship between the target EGR rate and the target EGR opening. Then, the EGR valve 37 is driven based on the target EGR opening, and the EGR gas amount is adjusted accordingly. At this time, the EGR valve 37 does not add an EGR response and is immediately controlled according to the target EGR rate.

  In the actual EGR rate calculation unit M25, based on the target EGR opening degree and the delay in response until the EGR gas that has passed through the EGR valve 37 flows into the engine cylinder, the EGR rate when the EGR gas flows into the cylinder A certain actual EGR rate is calculated. At this time, response restriction is performed on the target EGR opening using an air model that simulates the behavior related to in-cylinder inflow of EGR gas, and the actual EGR rate is calculated. Note that the air model used in the actual EGR rate calculation unit M25 may be the same as the air model used in the response limiting unit M22, and is expressed as a first-order lag model.

  The actual EGR rate calculated by the actual EGR rate calculation unit M25 is used for calculation of the target throttle opening by the target opening calculation unit M15. As a result, the target throttle opening can be appropriately calculated while taking into account the EGR response when the EGR gas is introduced.

  Next, an air amount control processing procedure performed by the microcomputer 51 of the ECU 50 and an EGR control processing procedure will be described with reference to the flowcharts of FIGS. 7 and 8. The processing shown in these flowcharts is repeatedly performed by the microcomputer 51 at a predetermined cycle.

  First, in the flowchart of FIG. 7 showing the processing procedure of the air amount control, in step S11, the required torque of the engine 10 is calculated based on the engine speed NE and the accelerator operation amount. In subsequent step S12, various corrections for engine loss and efficiency are performed on the required torque to calculate a target torque. At this time, the correction based on the ignition efficiency E1, the air-fuel ratio efficiency E2, and the EGR efficiency E3 is performed regarding the efficiency correction.

  Thereafter, in step S13, the target charge air amount is calculated based on the target torque using the charge air amount model, and in step S14, the target charge air amount and the actual charge air amount (actual throttle opening) are calculated using the intake system model. The target throttle opening is calculated on the basis of the actual EGR rate and the estimated charge air amount estimated from the degree and the actual intake air amount. Further, in step S15, feedback control of the throttle opening is performed based on the target throttle opening and the actual throttle opening.

  In the flowchart of FIG. 8 showing the processing procedure of EGR control, in step S21, the target EGR rate T1 is calculated based on the target charge air amount and the engine speed NE. In the subsequent step S22, the target EGR rate T1 is limited based on the delay of the EGR valve response, and the target EGR rate T2 with response limit is calculated. In step S23, a deviation (= T2−T1) between the target EGR rate T1 that is not response-restricted and the target EGR rate T2 that is response-restricted is calculated, and in step S24, EGR rate deviation is calculated based on the EGR rate deviation. The efficiency E3 is calculated.

  In step S25, the target EGR opening is calculated based on the target EGR rate calculated in step S21. In step S26, the EGR opening degree is controlled. In this case, the EGR valve 37 is driven based on the target EGR opening, and the EGR gas amount is adjusted accordingly. Thereafter, in step S27, the actual EGR rate is calculated based on the target EGR opening degree and the delay of the EGR response.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  In the above configuration, when the required torque is corrected, the EGR efficiency E3, which is a correction parameter for torque correction, is calculated based on the deviation between the target EGR rate T2 with response limitation and the target EGR rate T1 without response limitation. Therefore, torque control can be carried out in consideration of changes in torque loss and combustion state associated with the introduction of EGR gas. In this case, when the target EGR rate changes (transient), torque correction is performed in consideration of the response delay of the actual EGR rate with respect to the change in the target EGR rate. For this reason, it is possible to appropriately cope with the transient response when the EGR gas is introduced. As described above, high accuracy and stabilization of torque control at the time of introduction of EGR gas can be realized.

  Incidentally, as another method for correcting the influence on the torque associated with the introduction of EGR gas, an air flow meter 12 is used to detect the change in intake air amount associated with the introduction of EGR gas. It is conceivable that the actual EGR rate is estimated based on the actual intake air amount and torque correction is performed based on the estimated value of the actual EGR rate. However, in such a case, a calculation loop (feedback loop) of “actual intake air amount → estimation of actual EGR rate → torque correction → intake air amount control” is formed, and there is a concern that the system may diverge due to the loop. Is done. For example, when the actual intake air amount increases, the estimated value of the actual EGR rate decreases, and the intake air amount is controlled to increase to compensate for the increase in cooling loss caused by the decrease in the actual EGR rate. As a result, system divergence occurs and control becomes unstable. In this respect, in the present embodiment, since the response limitation of the target EGR rate is performed to cope with the delay of the EGR response, the feedback loop can be eliminated regarding the torque correction based on the EGR rate. As a result, the system can be stabilized.

  In particular, when an LGR (low-pressure loop) EGR system is used, the response delay of EGR becomes relatively large and the influence on torque control becomes large. Even in such a system, appropriate torque control can be realized.

  The configuration is such that the EGR efficiency E3 is calculated such that as the deviation between the target EGR rate T2 whose response is limited and the target EGR rate T1 whose response is not limited is larger, the torque increase correction amount is larger (see FIG. 5). Therefore, torque correction can be performed in consideration of the degree of EGR response delay.

  When the target EGR rate T1 changes to the increase side and to the decrease side, the EGR efficiency E3 is calculated so as to decrease as the EGR rate deviation (= T2−T1) increases. As a result, proper torque control can be performed when an EGR transient occurs.

  When the target EGR rate T2 whose response is limited with respect to the target EGR rate T1 whose response is not limited is small, the EGR efficiency E3 is calculated to reflect the increase in the cooling loss of the internal combustion engine, and the target whose response is not limited When the target EGR rate T2 whose response is limited with respect to the EGR rate T1 is large, the EGR efficiency E3 is calculated by reflecting that the combustion of the internal combustion engine is deteriorated due to excessive EGR (see FIG. 5). Therefore, appropriate transient response control can be performed in both cases where the target EGR rate increases and decreases.

  The target EGR opening is calculated from the target EGR rate, and the EGR valve 37 is controlled by the target EGR opening, while the actual EGR rate is calculated by reflecting the EGR response in the target EGR opening, and the actual EGR rate is used. The target throttle opening was calculated. In this case, since the operation of the EGR valve 37 is controlled without adding an EGR response, a quick transient response can be realized when the EGR valve 37 is operating. In addition, the actual EGR rate is calculated by reflecting the EGR response in the target EGR opening, and the throttle opening is controlled using the actual EGR rate. Therefore, the amount of EGR gas actually flowing into the engine cylinder is reflected. However, the air amount control can be properly performed.

  You may change the said embodiment as follows, for example.

  A configuration in which the target EGR rate T1 is determined to change to the increasing side and to the decreasing side, and torque correction based on the EGR rate deviation is performed only when it is determined that these changes occur. Also good.

  In the above embodiment, the target throttle opening as the air amount control parameter is calculated on the basis of the actual EGR rate calculated by limiting the target EGR opening, but this is changed and the actual EGR rate is changed. The target charge air amount as the air amount control parameter may be calculated based on the above.

  -As an external EGR system, an HPL (high-pressure loop) EGR system may be used. In this EGR system, an EGR pipe is provided so as to connect the upstream side of the exhaust turbine 32 in the exhaust pipe 26 and the downstream side of the intake compressor 31 in the intake pipe 11. In this case as well, as described above, torque correction based on EGR efficiency may be performed.

  As the torque correction, in addition to the above, efficiency correction based on the opening / closing timing of the intake valve by the intake side valve mechanism 21 and efficiency correction based on the opening / closing timing of the exhaust valve by the exhaust side valve mechanism 22 may be performed. .

  -This invention is applicable also to internal combustion engines other than a gasoline engine, for example, a diesel engine.

  DESCRIPTION OF SYMBOLS 10 ... Engine (internal combustion engine), 36 ... EGR piping, 37 ... EGR valve, 50 ... ECU, 51 ... Microcomputer (torque control means, EGR control means, target EGR rate setting means, response limiting means, correction parameter calculation means, torque Correction means).

Claims (5)

Based on the required torque determined according to the user's request, the torque control means for controlling the torque generated in the internal combustion engine (10) and the EGR valve (37) provided in the EGR pipe (36) are driven, An internal combustion engine control device comprising: EGR control means for controlling a flow rate of EGR gas recirculated from the exhaust side to the intake side via the EGR pipe,
Target EGR rate setting means for setting a target EGR rate that is a target value of the EGR rate in the internal combustion engine;
Response limiting means for limiting response of the target EGR rate based on a delay in response until the EGR gas that has passed through the EGR valve flows into the cylinder of the internal combustion engine;
Based on a deviation between the target EGR rate whose response is limited by the response limiting means and the target EGR rate which is not response-limited, a correction parameter for correcting the influence on the torque associated with the introduction of EGR gas is calculated. Correction parameter calculation means for
Torque correction means for correcting the required torque with the correction parameter calculated by the correction parameter calculation means;
A control device for an internal combustion engine, comprising:   2. The correction parameter calculation unit calculates the correction parameter such that a torque increase correction amount increases as a deviation between the response-limited target EGR rate and the non-response-limited target EGR rate increases. The control apparatus of the internal combustion engine described in 1.   When the target EGR rate set by the target EGR rate setting unit changes to the increase side and when the target EGR rate changes to the decrease side, the correction parameter calculation unit does not limit the response to the target EGR rate that has been response limited. The control device for an internal combustion engine according to claim 1 or 2, wherein the correction parameter is calculated based on a deviation from a target EGR rate.   The correction parameter calculation means reflects the increase in cooling loss of the internal combustion engine when the target EGR rate that is response-restricted with respect to the target EGR rate that is not response-restricted is small. And the correction parameter is set so as to reflect that the combustion of the internal combustion engine is deteriorated due to excessive EGR when the target EGR rate whose response is limited with respect to the target EGR rate whose response is not limited is large. The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the controller is calculated. The torque control means has control parameter calculation means for calculating an air amount control parameter based on the required torque, and an air amount control means for controlling the intake air amount of the internal combustion engine based on the air amount control parameter. And
The EGR control means calculates a target EGR opening that is a target value of the opening of the EGR valve based on the target EGR rate, and controls the operation of the EGR valve by the target EGR opening. A control device for an internal combustion engine,
When the EGR gas flows into the cylinder, the target EGR opening calculated by the EGR control means is limited by the response delay until the EGR gas that has passed through the EGR valve flows into the cylinder of the internal combustion engine. An actual EGR rate calculating means for calculating an actual EGR rate that is an EGR rate of
5. The control device for an internal combustion engine according to claim 1, wherein the control parameter calculation unit calculates the air amount control parameter based on an actual EGR rate calculated by the actual EGR rate calculation unit.

Images