JP5195064B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that includes a throttle and an EGR valve in an intake system.

  An internal combustion engine having an external EGR device for recirculating exhaust gas into a cylinder is known. The external EGR device includes an EGR passage that connects the exhaust passage and the intake passage, and an EGR valve that is provided in the EGR passage. The amount of EGR gas recirculated into the cylinder (hereinafter referred to as EGR amount) can be controlled by the opening degree of the EGR valve.

  In such an internal combustion engine with an external EGR device, if the ratio of the EGR gas to the in-cylinder gas (hereinafter referred to as the EGR rate) is excessively increased, the combustion of the mixed gas becomes unstable and misfire occurs. . When misfire occurs, not only drivability is reduced due to torque fluctuation, but also the catalyst is damaged. For this reason, in an internal combustion engine with an external EGR device, at the time of deceleration, the EGR valve is closed simultaneously with the throttle, so that the amount of intake air is reduced by the closing of the throttle so that the EGR amount is also reduced.

  However, since EGR gas remains downstream of the EGR valve in the EGR passage, even when the EGR valve is closed at the same time as the throttle, the EGR rate temporarily increases rapidly due to the residual EGR gas flowing into the cylinder. It will be. For this reason, if the EGR rate during steady operation is set high, the EGR rate may exceed the combustion limit when the EGR rate suddenly rises temporarily during deceleration. In a conventional internal combustion engine, in order to prevent misfire during deceleration, the EGR rate during steady operation is set to be lower with a sufficient margin than the combustion limit.

  EGR has the effect of improving the fuel efficiency by reducing the pump loss of the internal combustion engine. The effect of reducing pump loss by EGR can be increased as the EGR rate is increased. Therefore, from the viewpoint of fuel efficiency, the EGR rate is desired to be set as high as possible. However, as described above, the EGR rate during steady operation cannot be set so high considering misfire during deceleration. If the EGR rate during steady operation is set high, it is necessary to suppress the rapid increase in the EGR rate during deceleration by some method.

As a technique for suppressing the rapid increase in the EGR rate during deceleration, there is a technique described in Japanese Patent Application Laid-Open No. 2006-194143. This technique estimates the in-cylinder EGR rate based on the intake pressure, the engine speed, and the EGR valve opening when a deceleration request is made to the internal combustion engine, and the estimated EGR rate falls below a predetermined value. Until then, the throttle opening at the time of deceleration request is maintained. According to this technique, since the throttle is closed after the residual EGR gas in the intake passage becomes sufficiently small, an increase in the relative EGR rate accompanying a decrease in the intake air amount can be suppressed low.
JP 2006-194143 A

  However, the technique described in Japanese Patent Application Laid-Open No. 2006-194143 has a problem in that the speed reduction performance of the internal combustion engine is sacrificed. In this technique, when the deceleration request is made, the throttle is not closed immediately, but the throttle opening at the time of the deceleration request is maintained for a while. Therefore, the decrease in the engine speed is delayed by that amount. In order to prevent misfire, it is important to suppress the rapid increase in the EGR rate at the time of deceleration. However, it is not preferable from the viewpoint of drivability that the deceleration performance is reduced.

  The present invention has been made in order to solve the above-described problems, and is an internal combustion engine that can prevent a misfire by suppressing an increase in the EGR rate at the time of deceleration while ensuring a deceleration performance according to a deceleration request. An object of the present invention is to provide a control device.

In order to achieve the above object, a first aspect of the invention controls an internal combustion engine having an EGR valve provided in an EGR passage connecting an exhaust passage and an intake passage of the internal combustion engine, and a throttle provided in the intake passage. In the device
Deceleration request acquisition means for acquiring a deceleration request to the internal combustion engine;
When the deceleration request is acquired, the throttle is operated in the closing direction, and the throttle is moved to an intermediate opening between the final throttle opening determined based on the magnitude of the deceleration request and the throttle opening at the time when the deceleration request is acquired. Intake control means for temporarily stopping or slowing down the closing operation of the throttle when closed;
It is characterized by having.

In order to achieve the above object, the second invention has an EGR valve provided in an EGR passage connecting an exhaust passage and an intake passage of the internal combustion engine, and a throttle provided in the intake passage. In the control device of
EGR amount calculation means for calculating the amount of EGR gas flowing into the cylinder of the internal combustion engine (hereinafter referred to as EGR amount) based on the operating state of the internal combustion engine;
Combustion limit filling efficiency calculating means for calculating a combustion limit filling efficiency corresponding to a combustion limit of the internal combustion engine based on the EGR amount;
Deceleration request acquisition means for acquiring a deceleration request to the internal combustion engine;
When the deceleration request is acquired, the throttle is operated in the closing direction, and when the actual charging efficiency calculated from the opening of the throttle is reduced to the combustion limit charging efficiency, the closing operation of the throttle is temporarily stopped. Or intake control means for slowing down,
It is characterized by having.

According to a third aspect of the present invention, there is provided an internal combustion engine having an EGR valve provided in an EGR passage connecting an exhaust passage and an intake passage of the internal combustion engine and a throttle provided in the intake passage in order to achieve the above object. In the control device of
Deceleration request acquisition means for acquiring a signal indicating a deceleration request to the internal combustion engine;
Intake control means for converting the deceleration request signal into the throttle control signal via a plurality of parameters;
EGR amount calculation means for calculating the amount of EGR gas flowing into the cylinder of the internal combustion engine (hereinafter referred to as EGR amount) based on the operating state of the internal combustion engine;
Combustion limit filling efficiency calculating means for calculating a combustion limit filling efficiency corresponding to a combustion limit of the internal combustion engine based on the EGR amount;
The predetermined parameter value of the plurality of parameters is converted into a charging efficiency, and when the converted charging efficiency is smaller than the combustion limit charging efficiency, the predetermined parameter is set so that the charging efficiency is equal to or higher than the combustion limit charging efficiency. Correction means for correcting the value of
It is characterized by having.

According to a fourth invention, in the third invention,
The intake control means includes
Target torque setting means for setting a target torque of the internal combustion engine based on the deceleration request signal;
A target charging efficiency calculating means for calculating a target charging efficiency from the target torque;
Target throttle opening calculating means for calculating a target throttle opening from the target charging efficiency;
Control signal generating means for generating the control signal based on the target throttle opening,
The correction means uses the target charging efficiency as the predetermined parameter, and corrects the target charging efficiency to a value equal to or higher than the combustion limit charging efficiency when the target charging efficiency is smaller than the combustion limit charging efficiency. It is a feature.

A fifth invention is the fourth invention,
The correcting means guards the target charging efficiency with a lower limit value, and sets the combustion limit charging efficiency as a lower limit value.

According to a sixth invention, in the third invention,
The intake control means includes
Target torque setting means for setting a target torque of the internal combustion engine based on the deceleration request signal;
A target charging efficiency calculating means for calculating a target charging efficiency from the target torque;
Target throttle opening calculating means for calculating a target throttle opening from the target charging efficiency;
Control signal generating means for generating the control signal based on the target throttle opening,
The correction means uses the target torque as the predetermined parameter, and when the charging efficiency converted from the target torque is smaller than the combustion limit charging efficiency, based on the ratio of the combustion limit charging efficiency to the converted charging efficiency. Then, the target torque is corrected.

A seventh invention is the invention according to any one of the fourth to sixth inventions,
Estimated torque calculation means for calculating an estimated torque when the ignition timing is set to the optimal ignition timing based on the actual throttle opening;
Torque efficiency calculating means for calculating, as torque efficiency, a ratio between the target torque set based on the deceleration request signal and the estimated torque;
An ignition timing control means for calculating an ignition delay amount with respect to an optimal ignition timing using the torque efficiency, and controlling the ignition timing based on the ignition delay amount;
Is further provided.

In an eighth aspect based on the seventh aspect,
The internal combustion engine is an internal combustion engine having a plurality of cylinders,
A retard limit setting means for setting a retard limit value of the ignition timing based on the target charging efficiency and the EGR amount;
A retard limiting means for limiting the retard of the ignition timing with the retard limit value;
Retard angle limit torque calculating means for calculating a retard angle limit torque when the ignition timing is set to the retard angle limit value;
Cylinder deactivation means for deactivating some cylinders according to the torque difference when the retard limit torque is greater than the target torque;
Is further provided.

According to a ninth invention, in the seventh invention,
The internal combustion engine is an internal combustion engine capable of changing the opening timing of the exhaust valve,
A retard limit setting means for setting a retard limit value of the ignition timing based on the target charging efficiency and the EGR amount;
A retard limiting means for limiting the retard of the ignition timing with the retard limit value;
Retard angle limit torque calculating means for calculating a retard angle limit torque when the ignition timing is set to the retard angle limit value;
An exhaust valve control means for changing a valve opening timing of the exhaust valve according to the torque difference when the retard limit torque is larger than the target torque;
Is further provided.

  According to the first aspect of the present invention, when the deceleration is requested, the throttle is not closed at a stroke until the final throttle opening, but the closing operation is temporarily stopped or slowed down at the intermediate opening. The decrease in filling efficiency can be temporarily stopped or slowed down. According to this, it is possible to suppress an increase in the EGR rate when the residual EGR gas flows into the cylinder after the EGR valve is closed, and the EGR rate during steady operation can be set higher accordingly. . Further, according to the present invention, once the deceleration request is acquired, the throttle is temporarily closed to the intermediate opening, so that the rotational speed of the internal combustion engine can be quickly reduced from the time when the deceleration request is acquired. That is, according to this invention, it is possible to achieve both fuel efficiency and deceleration performance.

  According to the second aspect of the invention, instead of closing the throttle at a stroke to the final throttle opening when a deceleration request is made, the combustion limit charging efficiency is calculated based on the EGR amount, and the charging efficiency is reduced to the combustion limit charging efficiency. By temporarily stopping or slowing down the throttle closing operation at the time of the drop, the reduction in filling efficiency during the deceleration process can be temporarily stopped or slowed down. According to this, it is possible to prevent the EGR rate from exceeding the combustion limit due to a decrease in the charging efficiency, and accordingly, the EGR rate during steady operation can be set high. In addition, according to the present invention, after the deceleration request is acquired, the throttle can be closed until the charging efficiency reaches the combustion limit charging efficiency, so that the rotational speed of the internal combustion engine can be quickly reduced from the time when the deceleration request is acquired. it can. That is, according to this invention, it is possible to achieve both fuel efficiency and deceleration performance.

  According to the third invention, when there is a deceleration request to the internal combustion engine, the deceleration request signal is converted into a throttle control signal via a plurality of parameters. At that time, the value of a predetermined parameter among a plurality of parameters is converted into the charging efficiency, and when the converted charging efficiency becomes smaller than the combustion limit charging efficiency based on the EGR amount, the charging efficiency is set to be equal to or higher than the combustion limit charging efficiency. As described above, the value of the predetermined parameter is corrected. By performing such correction processing, the closing operation of the throttle can be temporarily stopped or slowed down in the process of closing the throttle to the final throttle opening. As a result, the decrease in the charging efficiency in the deceleration process temporarily stops or slows down immediately before the charging efficiency falls below the combustion limit charging efficiency, and the occurrence of misfire due to a rapid increase in the EGR rate is prevented. Therefore, according to the present invention, the EGR rate during steady operation can be set higher as much as the increase in the EGR rate during deceleration is suppressed. Further, according to the present invention, after the deceleration request is acquired, the throttle can be closed until the charging efficiency converted from the value of the predetermined parameter becomes smaller than the combustion limit charging efficiency. In addition, the rotational speed of the internal combustion engine can be reduced. That is, according to this invention, it is possible to achieve both fuel efficiency and deceleration performance.

  According to the fourth aspect of the invention, since the throttle control signal is generated based on the target throttle opening calculated from the target charging efficiency, the target charging efficiency is set to the future value of the charging efficiency realized by the operation of the throttle. Equivalent to. Therefore, when the target charging efficiency becomes smaller than the combustion limit filling efficiency, the target closing efficiency is corrected to a value equal to or higher than the combustion limit filling efficiency, so that the throttle closing operation is performed immediately before the charging efficiency actually falls below the combustion limit filling efficiency. By temporarily stopping or slowing down, it is possible to reliably prevent the charging efficiency from falling below the combustion limit charging efficiency.

  According to the fifth aspect of the invention, in order to correct the target charging efficiency, the target charging efficiency is compared with the combustion limit charging efficiency that is the lower limit value, and the larger of the target charging efficiency and the combustion limit charging efficiency is determined. Since only the selection is required, the calculation required for the correction process can be simplified, and the calculation load on the control device can be suppressed.

  According to the sixth aspect, the target charging efficiency is calculated from the target torque, and the throttle control signal is generated based on the target throttle opening calculated from the target charging efficiency. The efficiency corresponds to the future value of the charging efficiency realized by the operation of the throttle. Therefore, when the converted charging efficiency becomes smaller than the combustion limit charging efficiency, the target torque is corrected based on the ratio of the combustion limit charging efficiency to the converted charging efficiency before the actual charging efficiency falls below the combustion limit charging efficiency. In this case, the closing operation of the throttle is temporarily stopped or slowed down to reliably prevent the charging efficiency from falling below the combustion limit charging efficiency.

  According to the seventh aspect, the torque that can be realized with the actual throttle opening is calculated as the estimated torque of the internal combustion engine, and the ignition delay amount with respect to the optimal ignition timing based on the torque efficiency that is the ratio between the estimated torque and the target torque. Is calculated. Therefore, when the throttle closing operation is temporarily stopped or slowed down so that the EGR rate does not exceed the combustion limit, the ignition timing is automatically retarded so as to compensate for the delay in torque reduction caused thereby. Will be. Therefore, according to the present invention, it is possible to quickly reduce the generated torque of the internal combustion engine to the torque according to the deceleration request while suppressing the increase in the EGR rate during deceleration and preventing misfire.

  According to the eighth aspect of the present invention, when the retard of the ignition timing is limited by the retard limit value set based on the target charging efficiency and the EGR amount, the retard limit torque corresponding to the retard limit value. Some cylinders are deactivated according to the torque difference between the target torque and the target torque. Therefore, according to the present invention, it is possible to quickly reduce the generated torque of the internal combustion engine to the torque according to the deceleration request while surely preventing not only misfiring due to a rapid increase in the EGR rate but also misfiring due to the excessive delay of the ignition timing. Can do.

  According to the ninth aspect, when the retard of the ignition timing is limited by the retard limit set based on the target charging efficiency and the EGR amount, the retard limit torque corresponding to the retard limit is set. The opening timing of the exhaust valve is changed according to the torque difference between the target torque and the target torque. Therefore, according to the present invention, it is possible to quickly reduce the generated torque of the internal combustion engine to the torque according to the deceleration request while surely preventing not only misfiring due to a rapid increase in the EGR rate but also misfiring due to the excessive delay of the ignition timing. Can do.

  Prior to the description of the embodiments of the present invention, the points of the present invention common to the embodiments will be described with reference to FIGS.

  FIG. 1 is a graph showing a relationship among an intake air amount (hereinafter, air amount), an EGR amount, and a combustion limit EGR rate. The intake air amount (air amount) referred to in this specification is the in-cylinder intake air amount per cycle and is different from the air amount (air flow rate) flowing per unit time. A charging efficiency or load factor obtained by making the intake air amount dimensionless may be used. The solid line in the figure indicates the combustion limit EGR rate at each value of the air amount, and the region below this line is a combustible region. And the area | region above this line turns into a misfire area | region. Each broken line in the figure is a line showing the relationship between the air amount and the EGR rate when the EGR amount is constant. The relationship between the air amount and the EGR rate changes according to the magnitude of the EGR amount.

  Here, it is assumed that the operating state of the internal combustion engine determined by the air amount and the EGR amount is located at a point P0 on the graph of FIG. In this state, when a driver requests deceleration, the throttle is operated in the closing direction according to the magnitude of the deceleration request, and the air amount is decreased from the current KL0. KLref is the final air volume when the throttle is closed as required for deceleration.

  During deceleration, the EGR valve of the external EGR device is also closed. However, since EGR gas remains downstream of the EGR valve in the EGR passage, the amount of EGR flowing into the cylinder does not decrease immediately. Therefore, if the throttle is closed at once and the air amount is reduced to KLref, the EGR rate exceeds the combustion limit EGR rate and enters the misfire region, as indicated by a point P1 on the graph of FIG.

  Therefore, in the present invention, the air amount is not reduced from KL0 to KLref all at once, but is reduced to KLref2 before the EGR rate exceeds the combustion limit EGR rate as indicated by a point P2 on the graph of FIG. did. Then, as indicated by a point P3 on the graph of FIG. 1, after waiting for the EGR amount to decrease, the air amount is decreased from KLref2 to KLref. Such a change in the air amount can be realized by intake control using a throttle. In the present invention, the change in the air amount as described above is realized by temporarily stopping or slowing down the throttle closing operation during deceleration.

  FIG. 2 is a time chart showing temporal changes in engine speed, air amount, EGR valve open / close state, EGR amount, and EGR rate during deceleration. Regarding the air amount, the time change when the intake control according to the present invention is performed is shown by a solid line, and the time change by the conventional control is shown by a broken line. Further, the time change of the EGR rate realized by the intake control according to the present invention is indicated by a solid line, and the time change of the EGR rate in the case of the conventional control is indicated by a broken line.

  As shown in FIG. 2, according to the intake air control according to the present invention, the rate of decrease of the air amount is temporarily reduced during the process of decreasing the amount of air, so that the EGR rate increases due to a delay in the decrease of the EGR amount. Therefore, the EGR rate during steady operation can be set higher accordingly. On the other hand, in the case of the conventional control, the EGR rate suddenly rises with a sudden decrease in the air amount during deceleration, so the EGR rate during steady operation cannot be set too high. That is, when compared with the conventional control, it is possible to set the EGR rate at the time of steady operation higher than the conventional one by performing the intake control according to the present invention.

  In FIG. 2, the air amount decreases in two stages, but this is only an example of the form of air amount change realized by the intake control of the present invention. For example, if the throttle is gradually opened after the closing operation of the throttle is temporarily stopped or slowed down, the rate of decrease in the air amount gradually increases.

  Further, according to the intake air control according to the present invention, the air amount is not decreased at a stroke after waiting for the EGR amount to sufficiently decrease, but as shown in FIG. Since the amount is decreased, it is possible to eliminate the delay in the deceleration start with respect to the deceleration request. That is, by performing the intake air control according to the present invention, both fuel efficiency and deceleration performance can be achieved.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 3 is a block diagram showing the configuration of the control device for the internal combustion engine as the first embodiment of the present invention. The control device of the present embodiment is applied to an internal combustion engine with an external EGR device, and is configured as a control device that controls operations of a throttle and an EGR valve that are actuators of the internal combustion engine with an external EGR device. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  As shown in FIG. 3, the control device of the present embodiment includes an intake control unit 4 that controls the operation of the throttle 8 and an EGR control unit 6 that controls the operation of the EGR valve 10. Moreover, the deceleration request | requirement determination part 2 which determines the presence or absence of a driver | operator's deceleration request | requirement based on an accelerator opening is provided. When it is determined that there is a deceleration request, the deceleration request determination unit 2 transmits a deceleration request signal to the intake control unit 4 and the EGR control unit 6. The deceleration request signal includes the magnitude of the deceleration request as information. When receiving the deceleration request signal, the intake control unit 4 operates the throttle 8 in the closing direction. Further, the EGR control unit 6 that has received the deceleration request signal operates the EGR valve 10 in the closing direction.

  The control device of the present embodiment further includes an EGR amount calculation unit 12 and a combustion limit determination unit 14. The EGR amount calculation unit 12 calculates the EGR amount flowing into the cylinder of the internal combustion engine based on the opening degree of the EGR valve. For the calculation of the EGR amount, a mathematical formula or a map obtained by modeling the response of the EGR amount to the operation of the EGR valve based on fluid dynamics or the like can be used. Further, since the EGR amount and its changing speed are affected by the engine speed and the intake air amount, they are used as parameters in the calculation of the EGR amount.

  The combustion limit determination unit 14 calculates a combustion limit air amount corresponding to the combustion limit of the internal combustion engine based on the EGR amount calculated by the EGR amount calculation unit 12. Specifically, the combustion limit determination unit 14 stores a map of the relationship between the air amount, the EGR amount, and the combustion limit EGR rate shown in FIG. 1, and the combustion limit air amount is determined using this map. calculate. For example, in FIG. 1, when the EGR amount is egr1, the combustion limit air amount is KLref2. Next, the combustion limit determination unit 14 determines whether or not the current air amount is less than the combustion limit air amount, and inputs the determination result to the intake control unit 4. The current air amount is calculated based on the throttle opening.

  When it is determined that the air amount has decreased to the combustion limit air amount, the intake control unit 4 temporarily stops or slows down the closing operation of the throttle 8. Meanwhile, the EGR amount flowing into the cylinder decreases, and the combustion limit air amount also decreases accordingly. If it is determined that the combustion limit air amount has decreased below the final air amount determined from the magnitude of the deceleration request, the intake control unit 4 restarts the closing operation of the throttle 8 and the throttle 8 is made to the final throttle opening. It is supposed to close.

  As described above, the control device according to the present embodiment, when there is a deceleration request from the driver, does not close the throttle 8 to the final throttle opening at once, but when the air amount is reduced to the combustion limit air amount. Thus, the closing operation of the throttle 8 is temporarily stopped or slowed down. According to this, since the decrease in the air amount during the deceleration process is temporarily stopped or slowed down, the EGR rate is prevented from exceeding the combustion limit due to the decrease in the air amount, and misfire is prevented in advance. be able to. In addition, since the throttle 8 can be closed until the air amount reaches the combustion limit air amount after obtaining the deceleration request, the rotational speed of the internal combustion engine can be quickly reduced from the time when the deceleration request is obtained. That is, according to the control device of the present embodiment, it is possible to achieve both prevention of misfire and deceleration performance.

  In the present embodiment, the deceleration request determination unit 2 corresponds to the “deceleration request acquisition means” of the second invention. The EGR amount calculation unit 12 corresponds to the “EGR amount calculation unit” of the second invention, and a partial function of the combustion limit determination unit 14 corresponds to the “combustion limit charging efficiency calculation unit” of the second invention. Yes. The partial function of the combustion limit determination unit 14 and the intake control unit 4 constitute the “intake control means” of the second invention.

  Further, the present embodiment also corresponds to the first invention. In the present embodiment, the deceleration request determination unit 2 corresponds to the “deceleration request acquisition means” of the first invention. The combustion limit determination unit 14 and the intake control unit 4 constitute the “intake control means” of the first invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings.

  In the second embodiment, the present invention is applied to a torque demand type control device that sets a target torque and performs torque control according to the amount of air. FIG. 4 is a block diagram showing the configuration of the control device for the internal combustion engine as the second embodiment of the present invention. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  The accelerator opening signal is input to the control device of the present embodiment from an accelerator sensor (not shown). The accelerator opening signal is a signal reflecting the driver's accelerator operation, and a deceleration request is included in the accelerator opening signal. The input accelerator opening signal is converted into a target torque by the target torque setting unit 20. When the request included in the accelerator opening signal is an acceleration request, the target torque is set to a larger value, and when the request is a deceleration request, the target torque is set to a smaller value.

  The target torque is converted into the target air amount by the target air amount calculation unit 22. A map that defines the relationship between torque and air volume is used for the conversion. In this map, various operating conditions that affect the relationship between torque and air amount, such as engine speed, A / F, and ignition timing, are used as parameters. The target air amount (KLref) obtained by the target air amount calculation unit 22 is input to the target air amount correction unit 30.

  The EGR amount calculated by the EGR amount calculation unit 28 is also input to the target air amount correction unit 30. The EGR amount calculation unit 28 calculates the EGR amount that flows into the cylinder of the internal combustion engine based on the opening degree of the EGR valve. In FIG. 4, the control system of the EGR valve is omitted, but the opening degree of the EGR valve is controlled according to the air amount and the engine speed. At the time of deceleration, control is performed to operate the EGR valve in the closing direction so as to reduce the EGR amount. In calculating the EGR amount, a mathematical formula or a map obtained by modeling the response of the EGR amount to the operation of the EGR valve based on fluid dynamics or the like can be used. Further, since the EGR amount and its changing speed are affected by the engine speed and the air amount, they are used as parameters in the calculation of the EGR amount.

  The target air amount correction unit 30 stores a map of the relationship among the air amount, the EGR amount, and the combustion limit EGR rate shown in FIG. The target air amount correction unit 30 compares the EGR amount input from the EGR amount calculation unit 28 with the map data, and calculates a combustion limit air amount corresponding to the EGR amount. Then, the target air amount (KLref) is compared with the combustion limit air amount, and the larger one is output as the corrected target air amount (KLref2).

  The corrected target air amount (KLref2) is converted into the target throttle opening by the target throttle opening calculation unit 24. The air inverse model is used for conversion. The air inverse model is an inverse model obtained by modeling the response of the intake air amount to the operation of the throttle on the basis of fluid dynamics and the like and expressing it by a mathematical expression. The target throttle opening obtained by the target throttle opening calculation unit 24 is set in the throttle control unit 26. The throttle control unit 26 generates a control signal for operating the throttle based on the target throttle opening.

  As described above, when there is a deceleration request to the internal combustion engine, the control device of the present embodiment converts the deceleration request signal into a throttle control signal via the target torque, target air amount, and target throttle opening. Convert. At that time, the target air amount is compared with the combustion limit air amount, and the larger one is selected as the final target air amount, so that the throttle closing operation is temporarily stopped immediately before the air amount actually falls below the combustion limit air amount. Can be stopped or blunted. As a result, the decrease in the air amount during the deceleration process temporarily stops or slows down immediately before the air amount falls below the combustion limit air amount, and the occurrence of misfire due to a rapid increase in the EGR rate is prevented. Further, according to the control device of the present embodiment, after obtaining the deceleration request from the driver, the throttle can be closed until the target air amount becomes smaller than the combustion limit air amount. The speed of the internal combustion engine can be quickly reduced.

  In the present embodiment, the target torque setting unit 20 corresponds to the “deceleration request acquisition means” of the third invention. The target torque setting unit 20, the target air amount calculation unit 22, the target throttle opening calculation unit 24 and the throttle control unit 26 constitute the “intake control means” of the third invention. In particular, the target torque setting unit 20 corresponds to the “target torque setting means” of the fourth invention, the target air amount calculation unit 22 corresponds to the “target charging efficiency calculation means” of the fourth invention, and the target throttle opening degree The calculation unit 24 corresponds to “target throttle opening calculation means” of the fourth invention, and the throttle control unit 26 corresponds to “control signal generation means” of the fourth invention. Further, in the present embodiment, the EGR amount calculation unit 28 corresponds to “EGR amount calculation means” of the third invention. The target air amount correction unit 30 corresponds to the “combustion limit charging efficiency calculation means” of the third invention and the “correction means” of the third and fourth inventions.

  This embodiment also corresponds to the second invention. In the present embodiment, the target torque setting unit 20 corresponds to the “deceleration request acquisition means” of the second invention. The EGR amount calculation unit 28 corresponds to the “EGR amount calculation unit” of the second invention, and a partial function of the target air amount correction unit 30 corresponds to the “combustion limit charging efficiency calculation unit” of the second invention. . The target torque setting unit 20, the target air amount calculation unit 22, the target air amount correction unit 30, the target throttle opening calculation unit 24, and the throttle control unit 26 constitute the “intake control means” of the second invention. .

  Further, the present embodiment also corresponds to the first invention. In the present embodiment, the target torque setting unit 20 corresponds to the “deceleration request acquisition means” of the first invention. The target torque setting unit 20, the target air amount calculation unit 22, the target air amount correction unit 30, the target throttle opening calculation unit 24, and the throttle control unit 26 constitute the “intake control means” of the first invention. .

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to the drawings.

  FIG. 5 is a block diagram showing the configuration of the control device for the internal combustion engine as the third embodiment of the present invention. The control device of the present embodiment has a configuration in which a part related to the correction of the target air amount is partially modified while being based on the configuration of the control device of the second embodiment. In FIG. 5, elements common to the second embodiment are given the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the second embodiment is omitted or simplified, and the configuration different from the second embodiment is mainly described.

  The control device of the present embodiment includes an air amount ratio calculation unit 32 that calculates the ratio of the combustion limit air amount to the target air amount. The air amount ratio calculation unit 32 stores a map of the relationship among the air amount, the EGR amount, and the combustion limit EGR rate shown in FIG. The air amount ratio calculation unit 32 compares the EGR amount input from the EGR amount calculation unit 28 with the map data, and calculates a combustion limit air amount (KLref2) corresponding to the EGR amount. Then, an air amount ratio that is a ratio (= Klref2 / KLef) of the combustion limit air amount (KLref2) to the target air amount (KLref) is calculated. However, the air amount ratio is set to 1 or more, and the air amount ratio is set to 1 when the target air amount (KLref) is larger than the combustion limit air amount (KLref2).

  The air amount ratio is input to the target air amount correction unit 34 together with the target air amount (KLref). The target air amount correction unit 34 multiplies the target air amount (KLref) by the air amount ratio and outputs the multiplication result as a corrected target air amount. The corrected target air amount is converted into a target throttle opening, and the operation of the throttle is controlled by a control signal generated based thereon.

  The relationship between each component of the control device of the present embodiment and each of the first, second, third, and fourth inventions is the same as in the second embodiment. However, in the present embodiment, the air amount ratio calculation unit 32 corresponds to the “combustion limit charging efficiency calculation means” of the third invention, and the third and third operations are performed by the air amount ratio calculation unit 32 and the target air amount correction unit 34. The “correction means” of the fourth invention is configured.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to the drawings.

  In the fourth embodiment, the present invention is applied to a torque demand type control device that can control torque by using not only the air amount but also the ignition timing. FIG. 6 is a block diagram showing a configuration of a control device for an internal combustion engine as the fourth embodiment of the present invention. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  The internal combustion engine according to the present embodiment includes a throttle, a variable valve timing device, a variable valve lift amount device, an external EGR device (an EGR passage and an EGR valve) as actuators for controlling the operation thereof. ), An ignition device and a fuel supply device. In order to control these actuators, the control device shown in FIG. 6 includes a throttle control unit 70, a VVT control unit 72, a VL control unit 74, an external EGR control unit 76, an ignition timing control unit 78, and a driver for each actuator. A fuel supply control unit 80 is provided. These control units 70, 72, 74, 76, 78, 80 calculate the operation amount of the actuator in charge according to the control amount calculated from various information input to the control device.

  The information input to the control device includes requests regarding various functions of the internal combustion engine in addition to the operating state information of the internal combustion engine such as the engine speed. The functions of the internal combustion engine include drivability, exhaust gas, fuel consumption, noise, vibration, and the like. A host control device (not shown) that controls the entire drive device of the vehicle expresses the requests related to these functions as three physical quantities of torque, efficiency, and air-fuel ratio, and supplies them to the control device. That is, the torque request value, the efficiency request value, and the air-fuel ratio request value are input to the control device. The term “efficiency” as used herein means the conversion efficiency of thermal energy that can be converted into torque to torque, and is expressed as a ratio where the torque obtained at the optimal ignition timing is 1. The optimum ignition timing refers to the retard side of the MBT or trace knock ignition timing.

  In the present embodiment, the deceleration request issued by the driver through the accelerator operation is input to the host control device on the accelerator opening signal. Since the host controller calculates the torque request value from the accelerator opening signal and supplies it to the controller, the deceleration request for the internal combustion engine is expressed by the torque request value and input to the controller.

  Further, this control device has a function of estimating the operating state information of the internal combustion engine that cannot be obtained by measuring means such as a sensor or detecting means based on other information. Specifically, the estimated torque calculating unit 48 is provided as a function for estimating the torque, and the estimated EGR amount calculating unit 50 is provided as a function for estimating the EGR amount.

  The estimated torque calculation unit 48 calculates the torque obtained when the ignition timing is set to the optimum ignition timing based on the current throttle opening as the estimated torque. For the calculation of the estimated torque, various operating conditions that affect the relationship between the throttle opening and the torque, such as the engine speed, A / F, valve timing, and EGR valve opening, are used as parameters.

  The estimated EGR amount calculation unit 50 calculates the EGR amount obtained in the current operation state of the variable valve timing device, the variable valve lift amount device, and the external EGR device as the estimated EGR amount. Both the variable valve timing device and the variable valve lift amount device correspond to an internal EGR actuator that adjusts the internal EGR amount. The external EGR device can adjust the external EGR amount. For the calculation of the estimated EGR amount, a mathematical formula or a map obtained by modeling the response of the EGR amount to the operation of each actuator based on fluid dynamics or the like can be used. In these mathematical formulas and maps, various operating conditions that affect the response of the EGR amount, such as the engine speed and the intake air amount, can be used as parameters. In the first to third embodiments, the EGR amount thus calculated is simply expressed as the EGR amount, but in this embodiment, the estimation is made to clarify that it is not an actual value but an estimated value. Expressed as EGR amount.

  The control device includes a target torque setting unit 40 that sets a target value of torque of the internal combustion engine, a target efficiency setting unit 42 that sets a target value of efficiency, and a target A that sets a target value of an air-fuel ratio (hereinafter referred to as A / F). A / F setting unit 44 and a target EGR amount setting unit 46 for setting a target value of the EGR amount are provided. Among these, the target torque setting unit 40, the target efficiency setting unit 42, and the target A / F setting unit 44 set their respective target values based on the required values input from the host controller. The target EGR amount setting unit 46 sets the target EGR amount using a plurality of parameters indicating the operating state of the internal combustion engine, for example, a map having the engine speed and the required load as axes.

  The target torque and the target efficiency are used for calculating a target value of the intake air amount (hereinafter simply referred to as air amount). The target air amount is one of parameters used in a calculation process for converting a deceleration request signal into a throttle control signal. The target air amount is also used to generate control signals for the variable valve timing device, the variable valve lift amount device, and the external EGR device. The control device includes a target torque correction unit 52, a torque-air amount conversion unit 54, and a lower limit guard unit 56 as means for calculating the target air amount.

  The target torque and target efficiency are input to the target torque correction unit 52. The target torque correction unit 52 divides and corrects the target torque by the target efficiency, and outputs the corrected target torque to the torque-air amount conversion unit 54. If the target efficiency is a normal value of 1, the target torque set by the target torque setting unit 40 is output to the torque-air amount conversion unit 54 as it is. On the other hand, if the target efficiency is smaller than the normal value 1, the target torque is raised by division by the target efficiency, and the raised corrected target torque is output to the torque-air amount conversion unit 54.

  The torque-air amount conversion unit 54 calculates an air amount necessary for realizing the corrected target torque using an air amount map. The air amount map is a map for converting the corrected target torque into the air amount, and describes the relationship between the torque and the air amount when the ignition timing is the optimal ignition timing. In the air amount map, various operating conditions that affect the relationship between torque and air amount, such as engine speed, A / F, and EGR amount, are used as parameters. Among these, regarding the EGR amount, the larger one of the target EGR amount and the estimated EGR amount is selected by the maximum value selection unit 62 and input to the air amount map.

  FIG. 7 shows an image of the air amount map. As shown in this figure, the operating region of the internal combustion engine is divided into a combustible region and a misfire region depending on the relationship between the EGR amount and the air amount. The air amount map is created so that the relationship between the EGR amount and the air amount is within the combustible region. For example, even when the optimum air amount calculated from the corrected target torque and other parameter values such as the engine speed is α, the air amount map calculates β as the air amount in consideration of the EGR amount γ. It is like that.

  The air amount obtained by the torque-air amount conversion unit 54 is guarded by the lower limit guard unit 56. The lower limit guard unit 56 compares the input air amount with the combustion limit air amount, and outputs the input air amount as it is when the input air amount is equal to or greater than the combustion limit air amount. On the other hand, if the input air amount is smaller than the combustion limit air amount, the combustion limit air amount is output instead of the input air amount. The air amount output from the lower limit guard unit 56 is the final target air amount. The guard process by the lower limit guard unit 56 is a process for suppressing an increase in the EGR rate due to a decrease in the air amount, thereby ensuring operation in the combustible region.

  The combustion limit air amount used in the lower limit guard unit 56 is calculated by the combustion limit air amount calculation unit 58. The combustion limit air amount calculation unit 58 calculates the combustion limit air amount using the combustion limit air amount map. The combustion limit air amount map is a map in which the relationship between the EGR amount and the combustion limit air amount is stored, and various operating conditions that affect the combustion state when EGR is introduced, such as the engine speed, are used as parameters. . FIG. 8 is a diagram showing an image of a combustion limit air amount map. The EGR amount that is the basis for determining the combustion limit air amount is the EGR amount selected by the maximum value selection unit 62, that is, the larger EGR amount of the target EGR amount and the estimated EGR amount.

  The target air amount output from the lower limit guard unit 56 is used by the intake system target control amount calculation unit 60 together with the target EGR amount. The intake system target control amount calculation unit 60 calculates the control amount of each actuator using an air inverse model, a VVT model, a VL model, and an external EGR model. The VVT model is a numerical expression of the response of the internal EGR amount to changes in the valve timing of the intake valve and the exhaust valve. The VL model expresses the response of the internal EGR amount to a change in the lift amount of the intake valve by a mathematical expression. The external EGR model is a mathematical expression of the response of the external EGR amount to the operation of the EGR valve. The intake system target control amount calculation unit 60 calculates the target control amount of each actuator using these models, and sets it in the corresponding control units 70, 72, 74, 76. For example, the target throttle opening is set in the throttle control unit 70.

  Next, calculation of the operation amount of the actuator related to ignition will be described. An actuator related to ignition is an ignition device, and an ignition timing (represented by a crank angle) based on TDC is used as an operation amount. The control device calculates the target ignition timing in the target ignition timing calculation unit 68 and sets it in the ignition timing control unit 78.

  Torque efficiency is used for calculation of the target ignition timing in the target ignition timing calculation unit 68. The torque efficiency is a ratio of the target torque to the estimated torque of the internal combustion engine, and is calculated by the torque efficiency calculation unit 64. The torque efficiency calculation unit 64 divides the target torque set by the target torque setting unit 40 by the estimated torque calculated by the estimated torque calculation unit 48, and calculates the calculation result as torque efficiency. However, the torque efficiency output from the torque efficiency calculation unit 64 is not input to the target ignition timing calculation unit 68 as it is, but the corrected torque efficiency subjected to the guard processing by the lower limit guard unit 66 is input to the target ignition timing calculation unit 68. Entered.

  The target ignition timing calculation unit 68 first calculates an ignition delay amount with respect to the optimal ignition timing from the input torque efficiency. An ignition timing map is used to calculate the ignition retard amount. The ignition timing map is a multi-dimensional map with a plurality of parameters including torque efficiency as axes, and uses various operating conditions that affect the determination of ignition timing, such as EGR amount, A / F, and engine speed, as parameters. It has been. These parameters are entered with current values. However, the larger one of the target EGR amount and the estimated EGR amount is used for the EGR amount, and the target A / F is used for A / F.

  In the ignition timing map, the ignition delay amount when the torque efficiency is 1 is set to zero, and the smaller the torque efficiency is, the larger the ignition delay amount is set. Therefore, when the estimated torque and the target torque match, the torque efficiency becomes 1, so that the ignition retardation amount becomes zero. On the other hand, when the torque efficiency is smaller than 1, that is, when there is a difference between the estimated torque and the target torque, an ignition delay amount is calculated to compensate for the difference by torque adjustment by retarding the ignition timing. The The target ignition timing calculation unit 68 calculates the target ignition timing from the ignition delay amount determined using the ignition timing map and the optimal ignition timing determined from the operating state of the internal combustion engine, and sets it in the ignition timing control unit 78. To do.

  The torque efficiency guard process by the lower limit guard unit 66 is a process for preventing misfiring due to excessive retard of the ignition timing. The lower limit guard unit 66 compares the input torque efficiency with the lower limit efficiency, and outputs the torque efficiency as it is if the torque efficiency is equal to or higher than the lower limit efficiency. On the other hand, if the torque efficiency is smaller than the lower limit efficiency, the lower limit efficiency is output instead of the torque efficiency. Here, the lower limit efficiency is set according to the EGR amount. This is because, under the introduction of EGR, the possibility of misfire varies depending on the EGR amount even if the ignition retard amount is the same. As the EGR amount that determines the lower limit efficiency, the larger one of the target EGR amount and the estimated EGR amount is used.

  Finally, calculation of the operation amount of the actuator related to fuel supply will be described. An actuator related to fuel supply is a fuel supply device, and the drive time of the injector, that is, the fuel injection time is used as an operation amount. The fuel supply device may supply fuel directly into the cylinder or may inject fuel into the intake port. The fuel supply control unit 80 uses the target A / F set by the target A / F setting unit 44 as a control amount, and calculates a fuel injection time that is an operation amount based on the target A / F.

  The configuration and function of the control device according to the present embodiment have been described above. Next, the operation of the control device according to the present embodiment will be described with reference to FIG.

  FIG. 9 is a time chart showing the operation of the control device in response to a deceleration request from the driver. The deceleration request issued by the driver through the accelerator operation is expressed as a torque request value from the host controller and is input to the controller. The control device sets a target torque based on this torque request value. Specifically, as shown by the solid line at the top of the time chart, the target torque is greatly reduced stepwise to quickly respond to the deceleration request.

  The second stage of the time chart shows the change in the target air amount with a solid line. In the present embodiment, each of the torque-air amount conversion unit 54 and the lower limit guard unit 56 corrects the target air amount in consideration of the EGR amount. In the third stage of the time chart, the change in the throttle opening is shown by a solid line. As shown in this time chart, according to the control device of the present embodiment, the closing operation of the throttle can be temporarily stopped or slowed down in the process of closing the throttle to the final throttle opening.

  On the other hand, when the correction considering the EGR amount is not performed, the target air amount decreases stepwise in accordance with the change of the target torque, as indicated by a broken line in the second stage of the time chart. In this case, as indicated by a broken line in the third stage of the time chart, the throttle is closed at a stroke so as to undershoot the final throttle opening, and then returned to the final throttle opening.

  The fourth stage of the time chart shows the change in the EGR valve opening. When the target torque is reduced due to the deceleration request, the EGR valve is also operated in the closing direction in accordance with the operation in the closing direction of the throttle. The opening degree of the EGR valve at this time is controlled so as to realize the target EGR rate shown in the fifth stage of the time chart. The target EGR rate can be calculated from the target EGR amount and the target air amount set by the target EGR amount setting unit 46. In this embodiment, the target EGR amount is set, but the target EGR rate is set based on the engine speed, the required load, etc., and the target EGR amount is calculated from the target EGR rate and the target air amount. It may be calculated.

  In the fifth stage of the time chart, the actual EGR rate change is shown together with the target EGR rate. A solid line indicates a change in the EGR rate by the control device of the present embodiment, that is, a change in the EGR rate when the target air amount is corrected in consideration of the EGR amount. On the other hand, a broken line indicates a change in the EGR rate when the target air amount is not corrected.

  When the target air amount is not corrected, the EGR rate increases rapidly after the EGR valve is closed. This is because the EGR gas remaining downstream of the EGR valve flows into the cylinder. As a result, the EGR rate temporarily exceeds the target EGR rate, and when the target EGR rate is set at the limit of the combustion limit EGR rate, the possibility of misfire increases. On the other hand, according to the control device of the present embodiment, the throttle closing operation is temporarily stopped or slowed down immediately before the air amount falls below the combustion limit air amount, so that the increase in the EGR rate is suppressed, The occurrence of misfire due to a rapid rise in the EGR rate is prevented.

  At the bottom of the time chart, the change in the ignition timing by the control device of the present embodiment is shown by a solid line. According to the control device of the present embodiment, an estimated torque (indicated by a dotted line at the top of the time chart) when the ignition timing is set to the optimal ignition timing is calculated, and a torque that is a ratio between the estimated torque and the target torque Based on the efficiency, an ignition retardation amount with respect to the optimal ignition timing (indicated by a dotted line at the bottom of the time chart) is calculated. Therefore, when the decrease in the air amount is temporarily stopped or slowed down so that the EGR rate does not exceed the combustion limit, the ignition timing is automatically retarded so as to compensate for the delay in the decrease in torque. become.

  As described above, according to the control apparatus of the present embodiment, when there is a deceleration request to the internal combustion engine, the deceleration request signal is sent to the throttle via the target torque, target air amount, and target throttle opening. Convert to control signal. At that time, the target air amount is compared with the lower limit combustion limit air amount, and the target air amount is guarded by the combustion limit air amount. The closing operation can be temporarily stopped or slowed down. As a result, the decrease in the air amount during the deceleration process temporarily stops or slows down immediately before the air amount falls below the combustion limit air amount, and the occurrence of misfire due to a rapid increase in the EGR rate is prevented. Therefore, according to the control device of the present embodiment, the EGR rate during steady operation can be set higher as much as the increase in the EGR rate during deceleration is suppressed.

  Further, according to the control device of the present embodiment, after the deceleration request is acquired, the throttle can be closed until the target air amount becomes smaller than the combustion limit air amount. The engine speed can be reduced. Further, when the closing operation of the throttle is temporarily stopped or slowed down, the ignition timing is automatically retarded so as to compensate for the delay in torque reduction caused by the operation. Therefore, according to the control device of the present embodiment, it is possible to quickly reduce the generated torque of the internal combustion engine to the torque according to the deceleration request while suppressing the increase in the EGR rate during deceleration and preventing misfire.

  In the present embodiment, the target torque setting unit 40 corresponds to the “deceleration request acquisition means” of the third invention. Further, the target torque setting unit 40, the torque-air amount conversion unit 54, the intake system target control amount calculation unit 60, and the throttle control unit 70 constitute the “intake control means” of the third invention. In particular, the target torque setting unit 40 corresponds to the “target torque setting means” of the fourth invention, the torque-air amount conversion unit 54 corresponds to the “target charging efficiency calculation means” of the fourth invention, and the intake system target The control amount calculation unit 60 corresponds to “target throttle opening calculation means” of the fourth invention, and the throttle control unit 70 corresponds to “control signal generation means” of the fourth invention.

  In the present embodiment, the estimated EGR amount calculation unit 50 and the target EGR amount setting unit 46 correspond to the “EGR amount calculation means” of the third invention. The combustion limit air amount calculation unit 58 corresponds to “combustion limit filling efficiency calculation means” of the third invention. The lower limit guard unit 56 corresponds to the “correction unit” of the third to fifth inventions.

  In the present embodiment, the estimated torque calculator 48 corresponds to the “estimated torque calculator” of the seventh invention. The torque efficiency calculation unit 64 corresponds to the “torque efficiency calculation means” of the seventh invention. The target ignition timing calculation unit 68 and the ignition timing control unit 78 constitute the “ignition timing control means” of the seventh invention.

  This embodiment also corresponds to the second invention. In the present embodiment, the target torque setting unit 40 corresponds to the “deceleration request acquisition means” of the second invention. The estimated EGR amount calculation unit 50 corresponds to “EGR amount calculation means” of the second invention, and the combustion limit air amount calculation unit 58 corresponds to “combustion limit charging efficiency calculation means” of the second invention. The target torque setting unit 40, the torque-air amount conversion unit 54, the lower limit guard unit 56, the intake system target control amount calculation unit 60, and the throttle control unit 70 constitute the “intake control means” of the second invention. .

  Further, the present embodiment also corresponds to the first invention. In the present embodiment, the target torque setting unit 40 corresponds to the “deceleration request acquisition means” of the first invention. The target torque setting unit 40, the torque-air amount conversion unit 54, the lower limit guard unit 56, the combustion limit air amount calculation unit 58, the intake system target control amount calculation unit 60, and the throttle control unit 70, Control means "is configured.

Embodiment 5 FIG.
Next, a fifth embodiment of the present invention will be described with reference to the drawings.

  FIG. 10 is a block diagram showing a configuration of a control device for an internal combustion engine as the fifth embodiment of the present invention. Similar to the control device of the fourth embodiment, the control device of the present embodiment is a torque demand type control device that can control the torque by using not only the air amount but also the ignition timing. In FIG. 10, elements common to the fourth embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the fourth embodiment will be omitted or simplified, and a configuration different from that of the fourth embodiment will be described.

  In the present embodiment, unlike the fourth embodiment, the target EGR amount is not used to control the valve timing variable device, the valve lift amount variable device, and the external EGR device which are internal EGR actuators. In FIG. 10, the control system of these actuators is omitted, but these actuators are controlled using a map having air quantity and engine speed as main parameters. For example, in the case of an external EGR device, the opening degree of the EGR valve is controlled according to the air amount and the engine speed. Further, when there is a deceleration request, control is performed to operate the EGR valve in the closing direction so as to reduce the EGR amount.

  For this reason, the control device of the present embodiment does not have a function of setting the target EGR amount. That is, the target EGR amount setting unit 46 provided in the control device of the fourth embodiment is not provided in the control device of the present embodiment. Further, the maximum value selection unit 62 related to the target EGR amount is not provided with the control device of the present embodiment.

  The control device according to the present embodiment includes only a throttle among intake system actuators as a control target, and includes a target throttle opening calculation unit 82 as means for calculating a target control amount. The target throttle opening calculation unit 82 converts the target air amount into the target throttle opening using an air inverse model, and inputs the target throttle opening to the throttle control unit 70.

  The target air amount serving as the basis for the target throttle opening is calculated using the torque-air amount conversion unit 54 and the lower limit guard unit 56 as in the fourth embodiment. In the present embodiment, the estimated EGR amount calculated by the estimated EGR amount calculation unit 50 is used for correcting the target air amount. Specifically, the torque-air amount conversion unit 54 uses the estimated EGR amount as one of the parameters of the air amount map. Further, the lower limit guard unit 56 uses the combustion limit air amount determined from the estimated EGR amount as the lower limit value of the target air amount.

  In the present embodiment, the target throttle opening calculation unit 82 calculates the target throttle opening, the lower limit guard unit 66 sets the lower limit efficiency, and the target ignition timing calculation unit 68 calculates the ignition retard amount. The estimated EGR amount calculated by the estimated EGR amount calculation unit 50 is referred to.

  As described above, in the control device of the present embodiment, each EGR actuator is not controlled according to the target EGR amount, and the control of the EGR amount is performed independently of the control of the air amount. However, when the target air amount is lowered due to the deceleration request to the internal combustion engine, the combustion limit air amount calculated from the estimated EGR amount and the target air amount are compared, and the target air amount is automatically guarded by the combustion limit air amount. Is done. Therefore, according to the control device of the present embodiment, even if each EGR actuator is not controlled according to the target EGR amount, it is possible to suppress a temporary increase in the EGR rate during the deceleration process, and due to a sudden increase in the EGR rate. The occurrence of misfire can be prevented.

  The relationship between each component of the control device of the present embodiment and each of the first, second, third, fourth, fifth, and seventh inventions is the same as in the fourth embodiment. However, in the present embodiment, the target throttle opening calculation unit 82 corresponds to the “target throttle opening calculation means” of the fourth invention.

Embodiment 6 FIG.
Next, a sixth embodiment of the present invention will be described with reference to the drawings.

  FIG. 11 is a block diagram showing a configuration of a control device for an internal combustion engine as the sixth embodiment of the present invention. Similar to the control devices of the fourth and fifth embodiments, the control device of the present embodiment is a torque demand type control device that can control the torque by using not only the amount of air but also the ignition timing. In addition, the control device of the present embodiment is configured to use only the estimated EGR amount as information for calculating the control amount of each actuator, as in the control device of the fifth embodiment, without using the target EGR amount. It has become. In FIG. 11, elements common to the fifth embodiment are denoted by the same reference numerals.

  The control device of the present embodiment and the control device of the fifth embodiment include a plurality of units for converting a deceleration request signal into a throttle control signal so that the intake air amount does not fall below the combustion limit air amount determined from the EGR amount. This is common in that one of the parameters is corrected. However, the control device of the fifth embodiment corrects the target air amount, whereas the control device of the present embodiment is different in that the target torque is corrected.

  First, the target torque correction method employed in the present embodiment will be described with reference to FIG. 1 used in the description of the first embodiment. In the present embodiment, the target torque is converted into an air amount. The converted air amount is assumed to be KLref shown in FIG. Further, an EGR amount is acquired, and an air amount at which the EGR rate becomes the combustion limit EGR rate is calculated based on the EGR amount. Let the combustion limit air amount be KLref2 shown in FIG. In the present embodiment, the ratio of the combustion limit air amount to the air amount converted from the target torque (= KLref2 / KLef) is defined as the air amount ratio.

  Next, processing for converting the air amount ratio into the torque ratio is performed. In the present embodiment, the ratio of the torque that can be realized with the converted air amount to the torque that can be realized with the combustion limit air amount is defined as the torque ratio. The torque that can be realized with the converted air amount is the torque when the combustion limit EGR rate is ignored, and is equal to the target torque. According to this definition, the torque ratio is 1 when the converted air amount is equal to the combustion limit air amount, and is smaller than 1 when the converted air amount is less than the combustion limit air amount. However, the torque ratio is fixed to 1 when the converted air amount is larger than the combustion limit air amount.

  Next, the target torque is divided by the torque ratio, and the calculation result is used as the corrected target torque. The corrected target torque is equal to the torque that can be realized with the combustion limit air amount based on the EGR amount. In the present embodiment, the target air amount is calculated using the corrected target torque, and the throttle is controlled by calculating the target throttle opening from the target air amount.

  In the torque demand control employed in the present embodiment, the target air amount is calculated from the target torque, and the throttle is controlled based on the target throttle opening calculated from the target air amount. According to such a control sequence, the air amount converted from the target torque corresponds to a future value of the air amount realized by the operation of the throttle. Therefore, by correcting the target torque with a torque ratio corresponding to the ratio between the converted air amount and the combustion limit air amount, the throttle closing operation is temporarily stopped immediately before the actual air amount falls below the combustion limit air amount or Can be slowed down.

  The configuration for realizing the correction method described above is the configuration of the control device shown in FIG. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the fifth embodiment is omitted or simplified, and the configuration different from the fifth embodiment is mainly described.

  The control device of the present embodiment excludes the lower limit guard unit 56 and the combustion limit air amount calculation unit 58 from the control device of the fifth embodiment, and instead calculates for calculating the torque ratio used for correcting the target torque. The configuration is such that elements 84, 86 and 88 are added. In FIG. 11, the components that are common to the control device of the fifth embodiment, such as the target A / F setting unit, and are not related to the characteristic portions of the present embodiment are not shown. ing.

  In the control device of the present embodiment, the target torque set by the target torque setting unit 40 is input to the air amount conversion unit 84 in parallel with being input to the target torque correction unit 90 and the torque efficiency calculation unit 64. Is also entered. The air amount conversion unit 84 converts the target torque into an air amount under the precondition that the ignition timing is the optimal ignition timing. An air volume map is used for conversion. The air amount map used here may be the same as the air amount map used in the torque-air amount converter 54.

  The air amount obtained by the air amount conversion unit 84 is input to the air amount ratio calculation unit 86. The estimated EGR amount calculated by the estimated EGR amount calculation unit 50 is also input to the air amount ratio calculation unit 86 at the same time. The air amount ratio calculation unit 86 stores a map of the relationship between the air amount, the EGR amount, and the combustion limit EGR rate shown in FIG. The air amount ratio calculation unit 86 reads the combustion limit air amount corresponding to the estimated EGR amount from the map, and calculates the ratio of the combustion limit air amount to the air amount input from the air amount conversion unit 84.

  The conversion of the air amount ratio to the torque ratio is performed by the torque ratio calculation unit 88. The torque ratio calculation unit 88 calculates a torque ratio corresponding to the air amount ratio using a conversion formula or a map. As described above, if the air amount based on the target torque is equal to or greater than the combustion limit air amount based on the EGR amount, the torque ratio is 1. However, if the air amount is less than the combustion limit air amount, the torque ratio is smaller than 1. Become. The calculated torque ratio is input to the target torque correction unit 90.

  The target torque correction unit 90 corrects the target torque by dividing the target torque by the target efficiency and the torque ratio, and outputs the corrected target torque to the torque-air amount conversion unit 54. If the torque ratio is 1, the target torque corrected with the target efficiency is output to the torque-air amount converter 54. On the other hand, if the torque ratio is smaller than 1, the target torque is raised by division by the torque ratio, and the raised corrected target torque is output to the torque-air amount conversion unit 54.

  The torque-air amount conversion unit 54 calculates an air amount necessary for realizing the corrected target torque using an air amount map. Since the correction in consideration of the EGR amount has already been performed on the target torque, in the present embodiment, the air amount calculated by the torque-air amount conversion unit 54 is used as it is as the target air amount. That is, the air amount obtained by the torque-air amount conversion unit 54 is input to the target throttle opening calculation unit 82 as it is. The target throttle opening calculation unit 82 calculates the target throttle opening using an air inverse model, and sets the calculated target throttle opening in the throttle control unit 70. Although not shown in the drawing, the torque-air amount conversion unit 54 and the target throttle opening calculation unit 82 can also use the estimated EGR amount as reference information.

  In the present embodiment, the target torque setting unit 40 corresponds to the “deceleration request acquisition means” of the third invention. Further, the target torque setting unit 40, the torque-air amount conversion unit 54, the target throttle opening calculation unit 82, and the throttle control unit 70 constitute the “intake control means” of the third invention. In particular, the target torque setting unit 40 corresponds to “target torque setting means” of the sixth invention, and the torque-air amount conversion unit 54 corresponds to “target charging efficiency calculation means” of the sixth invention, and the target throttle opening. The degree calculator 82 corresponds to the “target throttle opening calculator” of the sixth invention, and the throttle controller 70 corresponds to the “control signal generator” of the sixth invention.

  In the present embodiment, the estimated EGR amount calculation unit 50 implements the “EGR amount calculation means” of the third invention, and the partial function of the air amount ratio calculation unit 86 enables the “combustion limit filling” of the third invention. "Efficiency calculation means" is realized. The air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, and the target torque correction unit 90 constitute the “correction means” of the third and sixth aspects of the invention. The relationship between each component of the control device of the present embodiment and each of the seventh inventions is the same as in the case of the fifth embodiment.

  This embodiment also corresponds to the second invention. In the present embodiment, the target torque setting unit 40 corresponds to the “deceleration request acquisition means” of the second invention. The estimated EGR amount calculation unit 50 corresponds to the “EGR amount calculation unit” of the second invention, and a partial function of the air amount ratio calculation unit 86 corresponds to the “combustion limit charging efficiency calculation unit” of the second invention. Yes. Then, the target torque setting unit 40, the air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, the target torque correction unit 90, the torque-air amount conversion unit 54, the target throttle opening calculation unit 82, and the throttle The control unit 70 constitutes the “intake control means” of the second invention.

  Further, the present embodiment also corresponds to the first invention. In the present embodiment, the target torque setting unit 40 corresponds to the “deceleration request acquisition means” of the first invention. Then, the target torque setting unit 40, the air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, the target torque correction unit 90, the torque-air amount conversion unit 54, the target throttle opening calculation unit 82, and the throttle The control unit 70 constitutes the “intake control means” of the first invention.

  In this embodiment, the combustion limit air amount is obtained from the estimated EGR amount when calculating the air amount ratio. However, a control device that controls each actuator using the target EGR amount calculates the combustion limit air amount. A target EGR amount may be used. For example, the target EGR amount and the estimated EGR amount may be compared to select the larger one, and the selected EGR amount may be input to the air amount ratio calculation unit 86.

Embodiment 7 FIG.
Next, a seventh embodiment of the present invention will be described with reference to the drawings.

  FIG. 12 is a block diagram showing a configuration of an internal combustion engine control apparatus according to Embodiment 7 of the present invention. The control device according to the present embodiment is based on the configuration of the control device according to the sixth embodiment, but has a configuration in which a part related to correction of the target torque is partially modified. In FIG. 12, elements common to the sixth embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the sixth embodiment is omitted or simplified, and the configuration different from that of the sixth embodiment is mainly described.

  The control device of the present embodiment is different from the control device of the sixth embodiment in the configuration of the part that reflects the torque ratio in the target torque. In the control device of the sixth embodiment, the target torque is divided by both the torque ratio and the target efficiency. For this reason, when both the torque ratio and the target efficiency are values smaller than 1, the target air amount obtained by the torque-air amount conversion unit 54 is greatly increased by the double correction of the target torque. According to the configuration shown in FIG. 11, the ignition timing is automatically retarded so as to compensate for the increased amount of air, so that the target torque can be realized, but the fuel consumption is increased by increasing the retard amount. Will get worse.

  Therefore, the control apparatus of the present embodiment employs a configuration that can prevent double correction of the target torque based on the torque ratio and the target efficiency. In the control device of the present embodiment, the torque ratio calculated by the torque ratio calculation unit 88 is input to the correction coefficient selection unit 92 as shown in FIG. The target efficiency set by the target efficiency setting unit 42 is also input to the correction coefficient selection unit 92. In the sixth embodiment, the target torque is corrected by using both the torque ratio and the target efficiency. However, in this embodiment, only one of the torque ratio and the target efficiency is selected and used for correcting the target torque. .

  The output of the correction coefficient selection unit 92 is automatically switched according to a predetermined switching condition. The target efficiency is selected when priority is given to the accuracy of ignition timing control, and the torque ratio is selected when priority is given to air amount control so that the EGR rate does not exceed the combustion limit during deceleration. For example, the target efficiency may be normally output, and when the torque ratio becomes smaller than 1, the torque ratio may be output. Further, the torque ratio and the target efficiency may be compared and the smaller one may be output. The target torque correction unit 52 divides the target torque by the torque ratio or target efficiency selected by the correction coefficient selection unit 92 and outputs the corrected target torque to the torque-air amount conversion unit 54.

  The relationship between each component of the control device of the present embodiment and each of the first, second, third, sixth and seventh inventions is the same as that of the sixth embodiment. However, in the present embodiment, the “correction means” according to the third and sixth aspects of the invention includes the air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, the correction coefficient selection unit 92, and the target torque correction unit 52. Is configured. In the present embodiment, the target torque setting unit 40, the air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, the target torque correction unit 52, the torque-air amount conversion unit 54, the target throttle opening. The degree calculating section 82 and the throttle control section 70 constitute the “intake control means” of the first and second aspects of the invention.

Embodiment 8 FIG.
Next, an eighth embodiment of the present invention will be described with reference to the drawings.

  FIG. 13 is a block diagram showing the configuration of the control apparatus for an internal combustion engine as the eighth embodiment of the present invention. The control device according to the present embodiment is based on the configuration of the control device according to the sixth embodiment, but has a configuration in which a part related to correction of the target torque is partially modified. In FIG. 13, elements common to the sixth embodiment are given the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the sixth embodiment is omitted or simplified, and the configuration different from that of the sixth embodiment is mainly described.

  As described above, in the configuration of the control device of the sixth embodiment, when the target torque is doubly corrected by the torque ratio and the target efficiency, the ignition timing is greatly retarded. For this reason, the control device of the seventh embodiment employs a configuration that can prevent double correction of the target torque. In contrast, the control device of the present embodiment employs a configuration in which the ignition timing is not retarded even if the target torque is corrected by the torque ratio. The purpose of correcting the target torque based on the torque ratio is to prevent the air amount from falling below the combustion limit air amount, so that the ignition timing delay for compensating the torque is not necessarily required.

  As shown in FIG. 13, in the control device of the present embodiment, the target torque set by the target torque setting unit 40 is first divided by the torque ratio by the target torque first correction unit 94. Then, the target torque corrected by the target torque first correction unit 94 is input to the torque efficiency calculation unit 64. According to this, since the ignition timing is retarded based on the ratio between the corrected target torque reflecting the torque efficiency and the estimated torque, the ignition timing is retarded when the torque ratio becomes smaller than 1. There is nothing.

  The control device according to the present embodiment includes a target torque second correction unit 96 that further divides the target torque corrected by the target torque first correction unit 94 by the target efficiency. Further, a target torque selection unit 98 that selects and outputs either one of the correction target torque output from the target torque first correction unit 94 and the correction target torque output from the target torque second correction unit 96 is provided. Yes. The corrected target torque selected by the target torque selector 98 is output to the torque-air amount converter 54. The output of the target torque selector 98 is automatically switched according to a predetermined switching condition. When priority is given to air amount control so that the EGR rate does not exceed the combustion limit during deceleration, the corrected target torque output from the target torque first correction unit 94 is selected. When the accuracy of the ignition timing control is prioritized, the corrected target torque output from the target torque second correction unit 96 is selected.

  The relationship between each component of the control device of the present embodiment and each of the first, second, third, and sixth inventions is the same as that of the sixth embodiment. However, in the present embodiment, the “correction means” of the third and sixth inventions is configured by the air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, and the target torque first correction unit 94. Yes. In the present embodiment, the target torque setting unit 40, the air amount conversion unit 84, the air amount ratio calculation unit 86, the torque ratio calculation unit 88, the target torque first correction unit 94, the torque-air amount conversion unit 54, the target The throttle opening calculation section 82 and the throttle control section 70 constitute the “intake control means” of the first and second inventions.

Embodiment 9 FIG.
Next, a ninth embodiment of the present invention will be described with reference to the drawings.

  FIG. 14 is a block diagram showing a configuration of a control device for an internal combustion engine as the ninth embodiment of the present invention. The control apparatus according to the present embodiment is based on the configuration of the control apparatus according to the fourth embodiment shown in FIG. FIG. 14 shows the configuration of the characteristic part of this embodiment. In FIG. 14, elements common to the fourth embodiment are denoted by the same reference numerals.

  In the control device of the fourth embodiment, which is the base of the present embodiment, the ignition timing control is performed according to the torque efficiency that is the ratio between the estimated torque and the target torque when the ignition timing is set to the optimum ignition timing. For this reason, when the internal combustion engine decelerates, if the throttle closing operation is temporarily stopped or slowed down so that the EGR rate does not exceed the combustion limit, automatic compensation is made so as to compensate for the delay in torque reduction caused by the throttle closing operation. Therefore, the ignition timing is retarded. However, if the ignition timing is retarded too much, misfire will occur. Therefore, in the control device of the fourth embodiment, the ignition timing is retarded by guarding the torque efficiency by the lower limit guard unit 66 (see FIG. 6). Restricted.

  Limiting the retard of the ignition timing is necessary to prevent misfire. However, since the torque cannot be reduced to the target torque, the deceleration performance is reduced. The control device of the present embodiment has been further improved in this regard. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  Calculation elements newly added in the present embodiment are a minimum torque calculation unit 100 and a cylinder deactivation determination unit 102. The minimum torque calculation unit 100 calculates the minimum torque that can be realized by the ignition timing control based on the target air amount output from the lower limit guard unit 56, that is, the torque when the ignition timing is retarded to the limit. The ignition timing when the torque efficiency is guarded by the lower limit guard 66 is the retard limit ignition timing.

  The minimum torque varies depending on the relationship between the air amount and the EGR amount. For this reason, the minimum torque calculation unit 100 stores a minimum torque map that describes the relationship among the air amount, the EGR amount, and the minimum torque. The minimum torque calculation unit 100 inputs the target air amount and the EGR amount to the minimum torque map, and outputs the minimum torque determined from those input conditions. Since the present embodiment is based on the fourth embodiment, the EGR amount used here is the larger of the target EGR amount and the estimated EGR amount.

  FIG. 15 is a diagram showing an image of the minimum torque map. In the figure, two curves showing the relationship between torque and EGR amount are drawn. The upper curve is a curve showing the relationship between the torque and the EGR amount when the ignition timing is set to the optimum ignition timing under the combustion limit air amount. The lower curve is a curve showing the relationship between the torque and the EGR amount when the ignition timing is set to the retard limit ignition timing under the combustion limit air amount. The torque range that can be realized by the ignition timing control is a range between the upper curve and the lower curve, and the torque range below the lower curve is a range that cannot be realized only by the ignition timing control. .

  In the present embodiment, when the target torque set by the target torque setting unit 40 (see FIG. 6) is smaller than the minimum torque, that is, even if the ignition timing is set to the retard limit ignition timing, the target torque cannot be realized. In some cases, some cylinders of the internal combustion engine are deactivated to reduce the torque. The cylinder deactivation is realized by stopping fuel supply to the cylinder, that is, by fuel cut. The cylinder deactivation may be accompanied by a stop of the operation of the intake valve or the exhaust valve.

  The cylinder deactivation determination unit 102 compares the minimum torque with the target torque and determines whether or not the target torque can be achieved. When it is determined that the target torque cannot be realized, the number of cylinders to be deactivated is determined according to the torque difference between the minimum torque and the target torque, and a cylinder deactivation flag indicating the number of deactivated cylinders is output. In response to the cylinder deactivation flag, the fuel supply control unit 80 (see FIG. 6) performs fuel cut on the target cylinder.

  As described above, the control device according to the present embodiment, when the retard of the ignition timing is limited by the retard limit ignition timing at the time of deceleration of the internal combustion engine, the minimum torque that can be realized at the retard limit ignition timing and the target Some cylinders are deactivated according to the torque difference from the torque. According to this, it is possible to quickly reduce the generated torque of the internal combustion engine to the torque according to the deceleration request while reliably preventing not only misfire due to the rapid increase in the EGR rate but also misfire due to the excessive delay of the ignition timing.

  In the present embodiment, the lower limit guard part 66 that guards the torque efficiency corresponds to the “retard angle limit setting means” and the “retard angle limit means” of the eighth invention. The minimum torque calculation unit 100 corresponds to the “retarding limit torque calculation unit” of the eighth invention, and the cylinder deactivation determination unit 102 and the fuel supply control unit 80 constitute the “cylinder deactivation unit” of the eighth invention. Has been.

  The configuration shown in FIG. 14 is based on the configuration of the control device according to the fourth embodiment. However, the minimum torque calculation unit 100 and the cylinder deactivation determination unit 102 which are characteristic portions of the present embodiment are the same as those in the fifth embodiment. It can also be combined with the control device of 8 thru | or 8.

Embodiment 10 FIG.
Next, a tenth embodiment of the present invention will be described with reference to the drawings.

  FIG. 16 is a block diagram showing a configuration of a control device for an internal combustion engine according to the ninth embodiment of the present invention. Similar to the control device of the ninth embodiment, the control device of the present embodiment is configured to compensate for the delay in torque reduction when the retard of the ignition timing is limited by other means. In FIG. 16, elements common to the ninth embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  The control device of the present embodiment and the control device of the ninth embodiment are different in the means for further reducing the torque when the ignition timing retardation is limited. In the present embodiment, the torque is reduced by changing the valve opening timing (hereinafter referred to as EVO) of the exhaust valve. For this reason, the control device of the present embodiment includes an EVO calculation unit 104 for calculating EVO instead of the cylinder deactivation determination unit 102 of the control device of the ninth embodiment.

  The EVO calculation unit 104 compares the minimum torque with the target torque to determine whether the target torque can be achieved. When it is determined that the target torque cannot be achieved, EVO is calculated based on the torque difference between the minimum torque and the target torque. The VVT control unit 72 (see FIG. 6) controls the variable valve timing device on the exhaust valve side so as to realize the calculated EVO. In FIG. 17, the range indicated by the solid line is the normal valve opening period of the exhaust valve, and when the target torque is lower than the minimum torque, the EVO is advanced as indicated by the broken line. As shown in the PV diagram of FIG. 18, by advancing EVO, the decrease in the in-cylinder pressure in the expansion stroke can be accelerated, and the torque can be decreased accordingly.

  As described above, the control device according to the present embodiment, when the retard of the ignition timing is limited by the retard limit ignition timing at the time of deceleration of the internal combustion engine, the minimum torque that can be realized at the retard limit ignition timing and the target The EVO is advanced according to the torque difference from the torque. According to this, it is possible to quickly reduce the generated torque of the internal combustion engine to the torque according to the deceleration request while reliably preventing not only misfire due to the rapid increase in the EGR rate but also misfire due to the excessive delay of the ignition timing.

  In the present embodiment, the lower limit guard unit 66 that guards the torque efficiency corresponds to the “retard angle limit setting means” and the “retard angle limit means” of the ninth invention. The minimum torque calculator 100 corresponds to the “retarding limit torque calculator” of the ninth invention, and the EVO calculator 104 and the VVT controller 72 constitute the “exhaust valve controller” of the ninth invention. ing.

  The configuration shown in FIG. 16 is based on the configuration of the control device according to the fourth embodiment. However, the minimum torque calculation unit 100 and the EVO calculation unit 104, which are characteristic parts of the present embodiment, are provided in the fifth to fifth embodiments. It can also be combined with eight control devices.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, as an embodiment of the third invention, instead of correcting the target air amount and target torque, the intake air amount is set to be equal to or higher than the combustion limit intake air amount (the charging efficiency is set to be equal to or higher than the combustion limit charging efficiency). Thus, the target throttle opening degree may be corrected.

It is a graph which shows the relationship between intake air amount, EGR amount, and combustion limit EGR rate. It is a time chart which shows each time change of the engine speed at the time of deceleration, air quantity, the opening-and-closing state of an EGR valve, EGR amount, and an EGR rate. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 1 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 2 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 3 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 4 of this invention. It is a figure which shows the image of the air quantity map used in the case of calculation of target air quantity. It is a figure which shows the image of the combustion limit air amount map used in the case of calculation of the combustion limit air amount. It is a time chart which shows operation | movement of the control apparatus of the internal combustion engine as Embodiment 4 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 5 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 6 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 7 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 8 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 9 of this invention. It is a figure which shows the image of the minimum torque map used in the case of calculation of the minimum torque. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 10 of this invention. It is a valve timing diagram for demonstrating the exhaust valve control which concerns on Embodiment 10 of this invention. It is a figure for demonstrating the torque reduction effect by adjustment of the valve opening time of an exhaust valve.

Explanation of symbols

2 Deceleration request determination unit 4 Intake control unit 6 EGR control unit 8 Throttle 10 EGR valve 12 EGR amount calculation unit 14 Combustion limit determination unit 20 Target torque setting unit 22 Target air amount calculation unit 24 Target throttle opening calculation unit 26 Throttle control unit 28 EGR amount calculation unit 30 Target air amount correction unit 32 Air amount ratio calculation unit 34 Target air amount correction unit 40 Target torque setting unit 42 Target efficiency setting unit 44 Target A / F setting unit 46 Target EGR amount setting unit 48 Estimated torque calculation Unit 50 estimated EGR amount calculation unit 52 target torque correction unit 54 torque-air amount conversion unit 56 lower limit guard unit 58 combustion limit air amount calculation unit 60 intake system target control amount calculation unit 62 maximum value selection unit 64 torque efficiency calculation unit 66 lower limit Guard unit 68 Target ignition timing calculation unit 70 Throttle control unit 72 VVT control unit 74 VL control unit 76 External EGR control unit 78 Ignition timing control unit 80 Fuel supply control unit 82 Target throttle opening calculation unit 84 Air amount conversion unit 86 Air amount ratio calculation unit 88 Torque ratio calculation unit 90 Target torque correction unit 92 Correction coefficient selection unit 94 Target torque first correction unit 96 Target torque second correction unit 98 Target torque selection unit 100 Minimum torque calculation unit 102 Cylinder deactivation determination unit 104 EVO calculation unit

Claims (2)

In a control device for an internal combustion engine having an EGR valve provided in an EGR passage connecting an exhaust passage and an intake passage of the internal combustion engine, and a throttle provided in the intake passage,
Deceleration request acquisition means for acquiring a deceleration request to the internal combustion engine;
When the deceleration request is acquired, the throttle is operated in the closing direction, and the throttle is moved to an intermediate opening between the final throttle opening determined based on the magnitude of the deceleration request and the throttle opening at the time when the deceleration request is acquired. Intake control means for temporarily stopping or slowing down the closing operation of the throttle when closed;
A control device for an internal combustion engine, comprising: In a control device for an internal combustion engine having an EGR valve provided in an EGR passage connecting an exhaust passage and an intake passage of the internal combustion engine, and a throttle provided in the intake passage,
EGR amount calculation means for calculating the amount of EGR gas flowing into the cylinder of the internal combustion engine (hereinafter referred to as EGR amount) based on the operating state of the internal combustion engine;
Combustion limit filling efficiency calculating means for calculating a combustion limit filling efficiency corresponding to a combustion limit of the internal combustion engine based on the EGR amount;
Deceleration request acquisition means for acquiring a deceleration request to the internal combustion engine;
When the deceleration request is acquired, the throttle is operated in the closing direction, and when the actual charging efficiency calculated from the opening of the throttle is reduced to the combustion limit charging efficiency, the closing operation of the throttle is temporarily stopped. Or intake control means for slowing down,
A control device for an internal combustion engine, comprising:

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