Control device for internal combustion engine system

Abstract

To provide a control device for an internal combustion engine system, which when an acceleration request is made by a driver, by more appropriately determine whether or not the acceleration request involves an insufficient amount of fresh air intake, can suppress deterioration of acceleration performance and generation of smoke and, further, more reduce a NOx generation amount.SOLUTION: A control device comprises: a fresh air supply acceleration request occurrence determination unit that, based on a supercharging-related quantity in the operating state of an internal combustion engine including the input of an acceleration request from a driver, determines whether or not the acceleration request is such that a fresh air intake amount of the internal combustion engine becomes insufficient; a fresh air supply acceleration request termination determination unit that, based on the supercharging-related quantity, determines whether or not the fresh air supply acceleration request ends; and a fresh air supply acceleration request time EGR reduction unit that forcibly reduces the opening of an EGR valve during a fresh air supply acceleration request period from when it is determined that the fresh air supply acceleration request occurs until it is determined that the fresh air supply acceleration request ends.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a control device for an internal combustion engine system having an EGR system that returns a portion of the exhaust gas to an intake air, and a turbocharger. [Background technology]

[0002] Conventionally, an EGR system is a typical system for reducing NOx emissions from an internal combustion engine mounted on a vehicle. Examples of components of an EGR system include an EGR pipe, an EGR cooler, a bypass pipe, an adjustment valve, and an EGR valve. The EGR pipe is a pipe connected from an exhaust path to an intake path and flows a part of the exhaust gas from the exhaust path to the intake path as EGR gas. The EGR cooler is disposed in the EGR pipe and adjusts (lowers) the temperature of the EGR gas in the EGR pipe. The bypass pipe is a pipe branched from the EGR pipe upstream of the EGR cooler, connected to the EGR pipe downstream of the EGR cooler, and bypasses the EGR cooler. The adjustment valve is provided at the connection point between the EGR pipe and the bypass pipe and adjusts the ratio between the amount of EGR gas passing through the EGR cooler and the amount of EGR gas passing through the bypass pipe. The EGR valve adjusts the opening of the EGR pipe to adjust the flow rate of EGR gas returned from the exhaust path to the intake path. The EGR system reduces the oxygen concentration in the intake air inside the cylinder by returning a portion of the exhaust gas to the intake air as EGR gas, and also reduces the amount of NOx generated by increasing the heat capacity through water vapor and lowering the temperature of the combustion gas.

[0003] For example, the opening of the EGR valve is adjusted by feedback control so that the actual EGR rate, which is the amount of EGR gas relative to the amount of intake air in the cylinder (amount of fresh intake air + amount of EGR gas), approaches a target EGR rate calculated according to the operating state of the internal combustion engine. In recent years, there has been a trend to increase the amount of EGR gas over a wider operating range in order to further reduce NOx emissions (there is a trend to set the target EGR rate to a higher value over a wider operating range).

[0004] If EGR is performed during a sudden acceleration request with the accelerator pedal depressed deeply, the amount of fresh air intake is reduced by the amount of EGR gas flow. During such acceleration, the target EGR rate is instantaneously changed according to the driving condition. However, since the opening of the EGR valve is tracked by feedback control, even if the target EGR rate is instantaneously reduced, the change in the opening of the EGR valve is slow, making it difficult to avoid an excessive EGR state at the start of acceleration. If there is an excessive EGR state during acceleration, the amount of fuel injected will be excessive compared to the amount of fresh air intake, which is undesirable as it may cause deterioration of acceleration and smoke.

[0005] For example, in the engine exhaust gas recirculation device described in Patent Document 1, when the amount of change in accelerator opening per unit time (accelerator operation speed) is equal to or greater than a first judgment value, it is judged that the engine is required to accelerate, and a command is issued to fully close the EGR valve. Also, in the engine exhaust gas recirculation device of Patent Document 1, when the demand for acceleration based on the amount of change in accelerator opening per unit time disappears and the accelerator opening is equal to or less than a second judgment value, the command to fully close the EGR valve is cancelled. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-122613 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the exhaust gas recirculation device of the engine described in Patent Document 1, when an acceleration request is made by depressing the accelerator suddenly (accelerator operation speed is high), the EGR valve is quickly fully closed based on the accelerator operation speed. This avoids a state in which the amount of fresh air intake is insufficient (excessive EGR state), and prevents deterioration of acceleration and generation of smoke. Note that while the EGR valve is fully closed, deterioration of acceleration and generation of smoke can be avoided, but the amount of NOx generated increases. In Patent Document 1, whether or not the EGR valve is fully closed is switched when acceleration is requested based on the amount of change per unit time of the accelerator opening (accelerator operation speed). However, when the vehicle speed is relatively low, the amount of fresh air intake is likely to be insufficient when acceleration is requested, and when the vehicle speed is relatively high, the amount of fresh air intake is often not insufficient when acceleration is requested. For this reason, it may not be possible to appropriately determine whether or not the acceleration request is one in which the amount of fresh air intake is insufficient. In other words, in the exhaust gas recirculation device of the engine described in the cited document 1, when acceleration is required, the EGR valve may be fully closed even though there is a sufficient amount of fresh air intake, which is undesirable in that it may increase the amount of NOx generated more than necessary.

[0008] The present invention has been devised in consideration of these points, and has an objective of providing a control device for an internal combustion engine system that, when a driver requests acceleration, can more appropriately determine whether the acceleration request results in an insufficient amount of fresh air intake, thereby not only suppressing deterioration of acceleration performance and the generation of smoke, but also further reducing the amount of NOx generated. [Means for solving the problem]

[0009] In order to solve the above problems, a first aspect of the present invention is a control device for an internal combustion engine system, the internal combustion engine system comprising an internal combustion engine, an EGR valve for adjusting an EGR amount for returning a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine, a supercharger for supercharging the intake air of the internal combustion engine, and the control device for detecting an operating state of the internal combustion engine and controlling the internal combustion engine based on the operating state. The control device has a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred if it is determined that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including an input of an acceleration request from a driver, and determines that the fresh air compensation acceleration request has occurred if it is determined that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is insufficient, and After the acceleration request in which the fresh air intake amount is insufficient is changed to the acceleration request in which the fresh air intake amount is not insufficient, a fresh air supplement acceleration request end determination unit for determining whether the fresh air supplement acceleration request has been generated or not; acceleration request and an EGR amount reducing unit at the time of fresh air compensation acceleration request which forcibly reduces the opening of the EGR valve during a fresh air compensation acceleration request period until it is determined that the fresh air compensation acceleration request period has ended. When the control device determines in the fresh air compensation acceleration request occurrence determination unit whether or not the acceleration request is one in which the fresh air intake amount is insufficient based on the supercharging-related amount, the control device calculates a supercharging pressure deviation by subtracting an actual supercharging pressure, which is the actual supercharging pressure of the internal combustion engine, from a target supercharging pressure, which is the supercharging pressure of the internal combustion engine that should be a target calculated based on the operating state, and determines that the fresh air compensation acceleration request, which is an acceleration request in which the fresh air intake amount is insufficient, has occurred if the fluctuation amount of the supercharging pressure deviation with respect to time, which is obtained by subtracting the previous supercharging pressure deviation from the current supercharging pressure deviation, is equal to or greater than a fresh air compensation acceleration request determination threshold value. A control device for an internal combustion engine system.

[0012] Next, the present invention The second invention is the above First invention The control device of the internal combustion engine system according to the present invention is a control device for an internal combustion engine system, the control device being configured to calculate the fresh air compensation acceleration request occurrence determination threshold value based on the operating state in the fresh air compensation acceleration request occurrence determination unit.

[0013] Next, a third aspect of the present invention is a control device for an internal combustion engine system according to the first or second aspect of the present invention, wherein the control device, when determining whether the acceleration request has ended in the fresh air supplement acceleration request end determination unit, and determining whether or not the acceleration request is terminated after the acceleration request in which the fresh air intake amount is insufficient is followed by an acceleration request in which the fresh air intake amount is not insufficient. A realizable target boost pressure, which is a boost pressure, is calculated based on the operating state and a map in which the realizable target boost pressure corresponding to the operating state is set, or is calculated using each parameter of the operating state, and it is determined that the acceleration request has ended when an actual boost pressure, which is the actual boost pressure of the internal combustion engine, becomes equal to or higher than the realizable target boost pressure. Alternatively, and determining whether or not the acceleration request is terminated after the acceleration request in which the fresh air intake amount is insufficient is followed by an acceleration request in which the fresh air intake amount is not insufficient. A realizable target supercharging pressure, which is a supercharging pressure, is calculated based on a map in which the realizable target supercharging pressure corresponding to the operating state is set and the operating state, or is calculated using each parameter of the operating state, and a supercharger driving energy that is predicted to be required to be input to the supercharger in order to make the supercharging pressure the realizable target supercharging pressure is calculated. a supercharger driving energy for determining the end of an acceleration request after the acceleration request in which the fresh air intake amount is insufficient is changed to an acceleration request in which the fresh air intake amount is not insufficient, based on a map in which the supercharger driving energy corresponding to the supercharging pressure and the operating state is set and on the realizable target supercharging pressure and the operating state, or on the realizable target supercharging pressure and each parameter of the operating state, and determines that the acceleration request has ended when actual driving energy, which is supercharger driving energy actually input to the supercharger and calculated using each parameter of the operating state, becomes equal to or greater than the realizable target driving energy.

[0014] Next, the present invention The fourth invention The first invention to the The third invention The control device for an internal combustion engine system according to any one of claims 1 to 5, wherein the control device is configured to, in the fresh air compensation acceleration request period, reduce the EGR amount by the fresh air compensation acceleration request period. The amount of fresh air intake is insufficient for acceleration request During this period, the opening degree of the EGR valve is reduced in accordance with the operating state.

[0015] Next, a fifth aspect of the present invention is a control device for an internal combustion engine system according to any one of the first to fourth aspects of the present invention, wherein the control device maintains, in the EGR reduction section during fresh air supplementary acceleration request, during an acceleration request period in which the fresh air intake amount is not insufficient during the fresh air supplementary acceleration request period, the opening degree of the EGR valve that was reduced during the acceleration request period in which the fresh air intake amount is insufficient. A sixth aspect of the present invention is a control device for an internal combustion engine system, the internal combustion engine system including an internal combustion engine, an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine, a supercharger that supercharges the intake air of the internal combustion engine, and the control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state. The control device has a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred when it is determined that the acceleration request is an acceleration request in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including an input of an acceleration request from a driver, and that the fresh air compensation acceleration request has occurred when it is determined that the acceleration request is an acceleration request in which the fresh air intake amount is insufficient, a fresh air compensation acceleration request end determination unit that determines whether or not the acceleration request has ended after transitioning from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient based on the supercharging-related amount, and a fresh air compensation acceleration request time EGR amount reduction unit that forcibly reduces the opening of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred to when it is determined that the acceleration request has ended. and determining whether or not the acceleration request is terminated after the acceleration request in which the fresh air intake amount is insufficient is followed by an acceleration request in which the fresh air intake amount is not insufficient. A realizable target boost pressure, which is a boost pressure, is calculated based on the operating state and a map in which the realizable target boost pressure corresponding to the operating state is set, or is calculated using each parameter of the operating state, and when an actual boost pressure, which is an actual boost pressure of the internal combustion engine, becomes equal to or higher than the realizable target boost pressure, it is determined that the acceleration request has ended, or and determining whether or not the acceleration request is terminated after the acceleration request in which the fresh air intake amount is insufficient is followed by an acceleration request in which the fresh air intake amount is not insufficient. A realizable target supercharging pressure, which is a supercharging pressure, is calculated based on a map in which the realizable target supercharging pressure corresponding to the operating state is set and the operating state, or is calculated using each parameter of the operating state, and a supercharger driving energy that is predicted to be required to be input to the supercharger in order to make the supercharging pressure the realizable target supercharging pressure is calculated. a supercharger driving energy for determining the end of an acceleration request after the acceleration request in which the fresh air intake amount is insufficient is changed to an acceleration request in which the fresh air intake amount is not insufficient,based on a map in which the supercharger driving energy corresponding to the supercharging pressure and the operating state is set and on the realizable target supercharging pressure and the operating state, or on the realizable target supercharging pressure and each parameter of the operating state, and determines that the acceleration request has ended when actual driving energy, which is supercharger driving energy actually input to the supercharger and calculated using each parameter of the operating state, becomes equal to or greater than the realizable target driving energy. A seventh aspect of the present invention is a control device for an internal combustion engine system, the internal combustion engine system including an internal combustion engine, an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine, a supercharger that supercharges the intake air of the internal combustion engine, and the control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state. The control device has a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred if it is determined that the acceleration request is an acceleration request for which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including input of an acceleration request from the driver, and determines that the fresh air compensation acceleration request has occurred if it is determined that the acceleration request is an acceleration request for which the fresh air intake amount is insufficient; a fresh air compensation acceleration request termination determination unit that determines whether the acceleration request has ended after transitioning from an acceleration request for which the fresh air intake amount is insufficient to an acceleration request for which the fresh air intake amount is not insufficient based on the supercharging-related amount; and an EGR reduction unit during fresh air compensation acceleration request that forcibly reduces the opening of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred to when it is determined that the acceleration request has ended. The control device is a control device for an internal combustion engine system in which, in the EGR reduction section during fresh air supplementary acceleration request, during a period of acceleration request in which the fresh air intake amount is insufficient during the fresh air supplementary acceleration request period, the opening degree of the EGR valve is reduced in accordance with the operating condition. An eighth aspect of the present invention is a control device for an internal combustion engine system, the internal combustion engine system including an internal combustion engine, an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine, a supercharger that supercharges the intake air of the internal combustion engine, and the control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state. The control device has a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred if it is determined that the acceleration request is an acceleration request for which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including input of an acceleration request from the driver, and determines that the fresh air compensation acceleration request has occurred if it is determined that the acceleration request is an acceleration request for which the fresh air intake amount is insufficient; a fresh air compensation acceleration request termination determination unit that determines whether the acceleration request has ended after transitioning from an acceleration request for which the fresh air intake amount is insufficient to an acceleration request for which the fresh air intake amount is not insufficient based on the supercharging-related amount; and an EGR reduction unit during fresh air compensation acceleration request that forcibly reduces the opening of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred to when it is determined that the acceleration request has ended. The control device is a control device for an internal combustion engine system, and in the EGR reduction section during fresh air supplementary acceleration request, during an acceleration request period in which the fresh air intake amount is not insufficient during the fresh air supplementary acceleration request period, maintains the opening degree of the EGR valve that was reduced during the acceleration request period in which the fresh air intake amount is insufficient. Effect of the Invention

[0016] According to the first aspect of the present invention, when a driver requests acceleration, the control device determines whether the acceleration request is one in which the fresh air intake amount is insufficient based on a supercharging-related amount related to supercharging. If the control device determines that the acceleration request is one in which the fresh air intake amount is insufficient, the control device forcibly reduces the opening of the EGR valve to avoid a shortage of the fresh air intake amount. Since the intake air in which fresh air and EGR gas are mixed is supercharged and filled into the cylinder of the internal combustion engine by the supercharger, the supercharging-related amount includes a fresh air-related amount related to fresh air. In other words, determining whether the fresh air intake amount is insufficient based on the supercharging-related amount can more appropriately determine whether the acceleration request is one in which the fresh air intake amount is insufficient compared to determining whether the acceleration request is one in which the fresh air intake amount is insufficient based on the accelerator opening. Therefore, by more appropriately determining whether the acceleration request is one in which the fresh air intake amount is insufficient (an acceleration request that requires a forcible reduction in the EGR valve), in addition to suppressing deterioration of acceleration and generation of smoke, the amount of NOx generated can be further reduced.

[0017] First invention According to the method, when judging whether the acceleration request will cause a shortage of the fresh air intake amount based on the supercharging-related amount, the judgment is based on the deviation between the target supercharging pressure and the actual supercharging pressure. Therefore, it is possible to more appropriately judge whether the acceleration request will cause a shortage of the fresh air intake amount, compared to the case where the acceleration request will cause a shortage of the fresh air intake amount based on the accelerator opening.

[0018] First invention According to the method, when the amount of change in the supercharging pressure deviation with respect to time becomes equal to or greater than the fresh air compensation acceleration request determination threshold, it is determined that the acceleration request is one that causes a shortage of the fresh air intake amount. This makes it possible to more appropriately determine whether the acceleration request is one that causes a shortage of the fresh air intake amount.

[0019] The second invention According to the method, the fresh air compensation acceleration request determination threshold is calculated (changed) based on the operating state, thereby making it possible to more appropriately determine whether or not the acceleration request results in a shortage of the fresh air intake amount.

[0020] It is preferable to appropriately determine the start timing of the fresh air compensation acceleration request period during which the opening of the EGR valve is forcibly reduced, and then to appropriately determine the end timing. If the end timing is determined too early, acceleration may deteriorate and smoke may be generated, and if the end timing is determined too late, the opening of the EGR valve will be forcibly reduced for a period longer than necessary, resulting in an increase in the amount of NOx generated more than necessary. The third invention In the above, by utilizing the fact that the actual boost pressure reaches the feasible target boost pressure before the actual boost pressure reaches the target boost pressure, or by utilizing the fact that the actual driving energy reaches the feasible target driving energy before the actual boost pressure reaches the target boost pressure, the end of the fresh air supplement acceleration request period can be determined at a more appropriate timing that is neither too early nor too late.

[0021] The fourth invention According to this, at the start of the fresh air replenishment acceleration request period (the period during which a fresh air replenishment acceleration request is occurring), the opening of the EGR valve is forcibly and instantly reduced to an appropriate opening (the amount of EGR gas is instantly reduced), thereby preventing a shortage of fresh air intake volume when acceleration is required.

[0022] The fifth invention According to the above, during the period when a fresh air replenishment acceleration request is made but a fresh air replenishment acceleration request is not occurring, the opening degree of the EGR valve that was reduced when a fresh air replenishment acceleration request was made is maintained (kept), thereby making it possible to appropriately continue to avoid a shortage of fresh air intake volume when acceleration is required. [Brief description of the drawings]

[0023] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of an internal combustion engine system as a whole; [Diagram 2] 13 is a flowchart illustrating an example of a processing procedure of “overall processing” according to the first embodiment. [Diagram 3] 3 is a flowchart illustrating an example of a process procedure of “EGR valve control during steady operation” described in the flowchart of FIG. 2. [Figure 4] FIG. 4 is a diagram illustrating an example of the operation of the first embodiment. [Diagram 5] FIG. 1 is a diagram for explaining an example of operation of a conventional system in which the opening of the EGR valve is not forcibly reduced (reduced by feedback) when acceleration is required. [Figure 6] 13 is a flowchart illustrating an example of a processing procedure of “overall processing” according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] [Example of schematic configuration of internal combustion engine system 1 (Figure 1)] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, an example of a schematic configuration of an internal combustion engine system 1 will be described with reference to Fig. 1. In the description of this embodiment, an internal combustion engine 10 (e.g., a diesel engine) mounted on a vehicle will be used as an example of the internal combustion engine. Note that the intake pipes 11A and 11B and the intake manifold 11C correspond to the intake path, and the exhaust manifold 12A and the exhaust pipes 12B and 12C correspond to the exhaust path.

[0025] The entire system will be described below in order from the intake side to the exhaust side. An air cleaner (not shown) and an intake air amount detection device 21 (e.g., an intake air flow rate sensor) are provided on the inflow side of the intake pipe 11A. The intake air amount detection device 21 outputs a detection signal corresponding to the flow rate of air (fresh intake air amount) taken in by the internal combustion engine 10 to the control device 50. The intake air amount detection device 21 is also provided with an intake air temperature detection device 28A (e.g., an intake air temperature sensor) and an atmospheric pressure detection device 23 (e.g., an atmospheric pressure sensor). The intake air temperature detection device 28A outputs a detection signal corresponding to the temperature of the intake air passing through the intake air amount detection device 21 to the control device 50. The atmospheric pressure detection device 23 outputs a detection signal corresponding to the surrounding atmospheric pressure to the control device 50.

[0026] The outlet side of the intake pipe 11A is connected to the inlet side of a compressor 35, and the outlet side of the compressor 35 is connected to the inlet side of the intake pipe 11B. The compressor 35 of the turbocharger 30 (corresponding to a supercharger) is driven to rotate by a turbine 36 which is driven to rotate by the energy of the exhaust gas (supercharger driving energy), and supercharges the intake air that has flowed in from the intake pipe 11A by compressing it and sending it to the intake pipe 11B.

[0027] A compressor upstream pressure detection device 24A (e.g., a pressure sensor) is provided in the intake pipe 11A upstream of the compressor 35. The compressor upstream pressure detection device 24A outputs a detection signal corresponding to the pressure of the intake air in the intake pipe 11A to the control device 50. A compressor downstream pressure detection device 24B (e.g., a pressure sensor) is provided in the intake pipe 11B downstream of the compressor 35 (at a position in the intake pipe 11B between the compressor 35 and the intercooler 16). The compressor downstream pressure detection device 24B outputs a detection signal corresponding to the pressure of the intake air in the intake pipe 11B to the control device 50.

[0028] An intercooler 16 is disposed upstream of the intake pipe 11B, and a throttle device 47 is disposed downstream of the intercooler 16. The intercooler 16 is disposed downstream of the compressor downstream pressure detection device 24B. An intake air temperature detection device 28B (e.g., an intake air temperature sensor) is provided between the intercooler 16 and the throttle device 47. The intake air temperature detection device 28B outputs a detection signal corresponding to the temperature of the intake air whose temperature has been reduced by the intercooler 16 to the control device 50.

[0029] The throttle device 47 is capable of adjusting the intake flow rate (amount of fresh air intake) by driving a throttle valve 47V that adjusts the opening of the intake pipe 11B based on a control signal from the control device 50. The control device 50 is capable of adjusting the opening of the throttle valve 47V by outputting a control signal to the throttle device 47 based on a detection signal from a throttle opening detection device 47S (e.g., a throttle opening sensor) and a target throttle valve opening.

[0030] The accelerator pedal depression amount detection device 25 is, for example, an accelerator pedal depression angle sensor, and is provided on the accelerator pedal. The control device 50 can detect the amount of depression of the accelerator pedal by the driver based on the detection signal from the accelerator pedal depression amount detection device 25.

[0031] The outflow side of the intake pipe 11B is connected to the inflow side of the intake manifold 11C, and the outflow side of the intake manifold 11C is connected to the inflow side of the internal combustion engine 10. A supercharging pressure detection device 24C (e.g., a pressure sensor) is provided downstream of the throttle device 47 in the intake pipe 11B (in the intake manifold 11C), and the outflow side of the EGR pipe 13 is connected to it. The supercharging pressure detection device 24C outputs a detection signal corresponding to the pressure of the intake air (supercharging pressure) immediately before it flows into the intake manifold 11C to the control device 50. From the outflow side of the EGR pipe 13 (the connection with the intake pipe 11B), the EGR gas that flows in from the inflow side of the EGR pipe 13 (the connection with the exhaust manifold 12A or the exhaust pipe 12B) is discharged into the intake pipe 11B.

[0032] The internal combustion engine 10 has a plurality of cylinders 45A-45D, and injectors 43A-43D are provided for each cylinder. Fuel is supplied to the injectors 43A-43D via a common rail 41 and fuel pipes 42A-42D, and the injectors 43A-43D are driven by control signals from a control device 50 to inject fuel into each of the cylinders 45A-45D. A fuel pressure detection device 73 is provided in the common rail 41, and fuel adjusted to a target fuel pressure by a fuel pump 72 is filled in the common rail 41. The control device 50 controls the fuel pump 72 so that the fuel pressure detected by the fuel pressure detection device 73 approaches the target fuel pressure.

[0033] The internal combustion engine 10 is provided with a crank angle detector 22A, a cam angle detector 22B, a coolant temperature detector 28C, and the like. The crank angle detector 22A is, for example, a rotation sensor, and outputs a detection signal corresponding to the rotation angle of the crankshaft of the internal combustion engine 10 to the control device 50. The cam angle detector 22B is, for example, a rotation sensor, and outputs a detection signal corresponding to the rotation angle of the camshaft of the internal combustion engine 10 to the control device 50. The control device 50 can detect the stroke and rotation angle of each cylinder based on the detection signals from the crank angle detector 22A and the cam angle detector 22B. The coolant temperature detector 28C is, for example, a temperature sensor, and outputs a detection signal corresponding to the temperature of the cooling coolant (cooling water temperature) circulated in the internal combustion engine 10 to the control device 50. Although not shown, an oil temperature detector is provided in the internal combustion engine 10. The oil temperature detector is, for example, a temperature sensor, and outputs a detection signal corresponding to the temperature of the oil circulated in the internal combustion engine 10 to the control device 50.

[0034] An inlet side of an exhaust manifold 12A is connected to the exhaust side of the internal combustion engine 10, and an inlet side of an exhaust pipe 12B is connected to the outlet side of the exhaust manifold 12A. The outlet side of the exhaust pipe 12B is connected to the inlet side of a turbine 36, and the outlet side of the turbine 36 is connected to the inlet side of an exhaust pipe 12C.

[0035] An inlet side of the EGR pipe 13 is connected to the upstream side of the exhaust pipe 12B (or the exhaust manifold 12A). The EGR pipe 13 corresponds to an EGR flow path, and communicates the exhaust pipe 12B with the intake pipe 11B, and is capable of returning a part of the exhaust gas flowing in the exhaust pipe 12B (or the exhaust manifold 12A) to the intake pipe 11B (returning a part of the exhaust gas to the intake). The EGR pipe 13 is provided with an EGR cooler 15 and an EGR valve 14. The control device 50 can adjust the flow rate of the EGR gas flowing in the EGR pipe 13 by adjusting the opening degree of the EGR valve 14. The inlet side of the bypass pipe 13B is connected to the upstream side of the EGR cooler 15 in the EGR pipe 13, and the outlet side of the bypass pipe 13B is connected to the downstream side of the EGR cooler 15 in the EGR pipe 13. An adjustment valve 14B is provided at one of the connection points between the EGR pipe 13 and the bypass pipe 13B. The bypass pipe 13B forms a path that causes the EGR gas flowing through the EGR pipe 13 to bypass the EGR cooler 15. The control device 50 controls the adjustment valve to adjust the ratio between the amount of EGR gas passing through the EGR cooler 15 and the amount of EGR gas passing through the bypass pipe 13B, thereby adjusting the temperature of the EGR gas.

[0036] Further, an exhaust manifold pressure detection device 26C (e.g., a pressure sensor) is provided on the upstream side of the exhaust pipe 12B (or the exhaust manifold 12A). The exhaust manifold pressure detection device 26C outputs a detection signal corresponding to the exhaust pressure in the exhaust manifold 12A to the control device 50.

[0037] The exhaust pipe 12B is provided with an exhaust temperature detection device 29. The exhaust temperature detection device 29 is, for example, an exhaust temperature sensor, and outputs to the control device 50 a detection signal corresponding to the exhaust temperature.

[0038] The outlet side of the exhaust pipe 12B is connected to the inlet side of the turbine 36, and the outlet side of the turbine 36 is connected to the inlet side of the exhaust pipe 12C. The turbine 36 is provided with a variable nozzle 33 capable of controlling the flow rate of exhaust gas led to the turbine 36 (capable of adjusting the degree of closure of the flow path that leads the exhaust gas to the turbine), and the closure degree (opening degree) of the variable nozzle 33 is adjusted by a nozzle driving device 31. The control device 50 is capable of adjusting the intake supercharging pressure by outputting a control signal to the nozzle driving device 31 to adjust the closure degree (opening degree) of the variable nozzle 33 based on a detection signal from a nozzle closure detection device 32 (e.g., a nozzle closure sensor) and a target variable nozzle closure degree (opening degree).

[0039] A turbine upstream pressure detection device 26A (e.g., a pressure sensor) is provided in the exhaust pipe 12B upstream of the turbine 36. The turbine upstream pressure detection device 26A outputs a detection signal corresponding to the exhaust pressure in the exhaust pipe 12B to the control device 50. A turbine downstream pressure detection device 26B (e.g., a pressure sensor) and an air-fuel ratio detection device 29AF (e.g., an A / F sensor) are provided in the exhaust pipe 12C downstream of the turbine 36. The turbine downstream pressure detection device 26B outputs a detection signal corresponding to the exhaust pressure in the exhaust pipe 12C to the control device 50. In addition, the air-fuel ratio detection device 29AF outputs a detection signal corresponding to the air-fuel ratio of the exhaust gas flowing in the exhaust pipe 12B to the control device 50.

[0040] An exhaust purification device 61 is connected to the outlet side of the exhaust pipe 12C. For example, when the internal combustion engine 10 is a diesel engine, the exhaust purification device 61 includes an oxidation catalyst, a particulate filter, a selective reduction catalyst, and the like.

[0041] The vehicle speed detection device 27 is, for example, a vehicle speed detection sensor, and is provided on the wheels of the vehicle, etc. The vehicle speed detection device 27 outputs a detection signal to the control device 50 according to the rotation speed of the wheels of the vehicle.

[0042] The control device 50 includes a CPU 51, a RAM 52, a storage device 53, a timer 54, and the like. The control device 50 (CPU 51) receives detection signals from the various detection devices described above and outputs control signals to the various actuators described above. The inputs and outputs of the control device 50 are not limited to the detection devices and actuators described above. The temperature and pressure of each part may be calculated by estimation without mounting a sensor. The control device 50 can detect the operating state of the internal combustion engine 10 based on detection signals from various detection devices including the detection devices described above, and controls various actuators including the actuators described above based on the operating state. The storage device 53 is, for example, a storage device such as a Flash-ROM or an EEPROM, and stores programs and data for executing control and self-diagnosis of the internal combustion engine. The RAM 52 includes a volatile memory and a non-volatile memory. The control device 50 (CPU 51) includes a fresh air supplement acceleration request occurrence determination unit 51A, a fresh air supplement acceleration request end determination unit 51B, an EGR amount reduction unit 51C when fresh air supplement acceleration is requested, and the like, but these will be described in detail later.

[0043] The throttle valve 47V and EGR valve 14 described above are actuators provided in the intake path and capable of increasing the boost pressure, and the variable nozzle 33 is an actuator provided in the exhaust path and capable of increasing the boost pressure.

[0044] [Processing procedure of the control device 50 according to the first embodiment (FIGS. 2 and 3)] Next, an example of a processing procedure of the control device 50 in the first embodiment will be described with reference to the flowcharts shown in Fig. 2 and Fig. 3. The control device 50 (CPU 51) starts up the "overall processing" shown in Fig. 2 at a predetermined time interval (several [ms] to several tens of [ms]), for example, and advances the processing to step S010.

[0045] In step S010, the control device 50 detects the operating state of the internal combustion engine, including the input of an acceleration request from the driver (e.g., a sudden depression of the accelerator pedal), and proceeds to step S015. The control device 50 detects the operating state based on the detection signals from the various detection devices described above, the operating states of the various actuators, and the like.

[0046] In step S015, the control device 50 calculates the required fuel injection amount based on, for example, the accelerator pedal depression amount (or the accelerator pedal depression amount and the internal combustion engine speed) and a map in which the required fuel injection amount is set, and proceeds to step S020.

[0047] In step S020, the control device 50 calculates the target boost pressure (pimtrg_1) based on, for example, the required fuel injection amount (or the required fuel injection amount and the internal combustion engine speed) and a map in which the target boost pressure is set, and proceeds to step S025.

[0048] In step S025, the control device 50 calculates a boost pressure deviation (pimdlt) which is the deviation between the target boost pressure (pimtrg_1) and the actual boost pressure (actual boost pressure), and diverts the process to step S030. The actual boost pressure, which is the actual boost pressure, was detected in step S010. Also, "boost pressure deviation (pimdlt)" = "target boost pressure (pimtrg_1)" - "actual boost pressure".

[0049] In step S030, the control device 50 calculates the amount of fluctuation (Δpimdlt) of the supercharging pressure deviation (pimdlt) with respect to time, and proceeds to step S035. Δpimdlt is calculated as the slope of the supercharging pressure deviation (pimdlt) (see "supercharging pressure deviation (pimdlt)" and "Δpimdlt" in FIG. 4).

[0050] In step S035, the control device 50 calculates a realizable target boost pressure (pimtrg_2) which is a boost pressure different from the target boost pressure (pimtrg_1) and is a realizable boost pressure, and proceeds to step S040. The control device 50 calculates the realizable target boost pressure (pimtrg_2) which is predicted to be realizable when the actuators (throttle valve 47V, EGR valve 14, variable nozzle 33 in this case) which are provided in the intake path or exhaust path of the internal combustion engine and capable of increasing the boost pressure are driven further (from the current operating state) toward the side which increases the boost pressure. For example, the control device 50 determines, from operating conditions such as the internal combustion engine speed, the internal combustion engine load, the intake and exhaust gas flow rates, the internal combustion engine coolant temperature, and the internal combustion engine oil temperature, the achievable target boost pressure (pimtrg_2), which is the boost pressure predicted to be achievable if the variable nozzle 33, the EGR valve 14, and the throttle valve 47V are driven in a direction that further increases the boost pressure.

[0051] For example, a map or the like is created in which the realizable target boost pressure (pimtrg_2) corresponding to the driving state is calculated using an experiment using an actual vehicle or a simulation using model control. The control device 50 calculates the realizable target boost pressure (pimtrg_2) based on the map and the driving state. Alternatively, the control device 50 calculates the realizable target boost pressure (pimtrg_2) using values ​​of various parameters based on model control.

[0052] In step S040, the control device 50 calculates the feasible target driving energy (etintrg) and the actual driving energy (etin) which is the actual supercharger driving energy, and proceeds to step S045. The feasible target driving energy (etintrg) is the supercharger driving energy predicted to be required to be input to the turbocharger (supercharger) in order to make the actual supercharging pressure (actual supercharging pressure) the feasible target supercharging pressure (pimtrg_2). The actual driving energy (etin) is the supercharger driving energy actually input to the turbocharger (supercharger).

[0053] For example, a map or the like is prepared in which the supercharger drive energy is calculated according to the supercharging pressure and the operating state (such as the exhaust gas flow rate and the variable nozzle closure degree) through experiments using an actual vehicle or simulations using model control. The control device 50 calculates the realizable target drive energy (etintrg) based on the map, the realizable target supercharging pressure (pimtrg_2), and the operating state. Alternatively, the control device 50 calculates the realizable target drive energy (etintrg) using the values ​​of various parameters based on model control.

[0054] The control device 50 calculates the actual driving energy (etin), for example, using the following (Equation 1). If there is no detection device (sensor, etc.) that detects the necessary parameters used in (Equation 1), the necessary parameters may be estimated or calculated from parameters obtained by other detection devices. etin=Cp*G4*T4*{1-[1 / (P4 / P6)]^[(K-1) / K]} (Formula 1) Cp: ​​exhaust gas specific heat at constant pressure (constant) G4: Gas flow rate + fuel injection amount T4: Exhaust gas temperature P4: Turbine inlet pressure (turbine upstream pressure) P6: Turbine outlet pressure (turbine downstream pressure) K: Specific heat ratio (constant)

[0055] In step S045, the control device 50 calculates the fresh air compensation acceleration request determination threshold (C1) based on the driving state, and proceeds to step S050. For example, a map is prepared in which the fresh air compensation acceleration request threshold is set according to the driving state, based on an experiment using an actual vehicle or a simulation using model control. The control device 50 calculates the fresh air compensation acceleration request determination threshold (C1) based on the map and the driving state.

[0056] In step S050, the control device 50 judges whether Δpimdlt (the amount of change in the boost pressure deviation (pimdlt) with respect to time) calculated in step S030 is equal to or greater than the fresh air compensation acceleration request judgment threshold (C1). If Δpimdlt is equal to or greater than the fresh air compensation acceleration request judgment threshold (C1) (Yes), the control device 50 advances the process to step S055, and if not (No), the control device 50 advances the process to step S060.

[0057] If the process proceeds to step S055, the control device 50 determines that a fresh air compensation acceleration request has occurred, sets the fresh air compensation acceleration request flag to ON, sets the EGR amount reduction flag to ON, and proceeds to step S075.

[0058] If the process proceeds to step S060, the control device 50 sets the EGR amount reduction flag to OFF, and proceeds to step S065.

[0059] In step S065, the control device 50 judges whether the actual drive energy (etin) is equal to or greater than the realizable target drive energy (etintrg). If the actual drive energy (etin) is equal to or greater than the realizable target drive energy (etintrg) (Yes), the control device 50 advances the process to step S070, and if not (No), the control device 50 advances the process to step S075.

[0060] When the process proceeds to step S070, the control device 50 determines that the request for acceleration of fresh air supplementation has ended, sets the fresh air supplementation acceleration request flag to OFF, and proceeds to step S075.

[0061] When the process proceeds to step S075, the control device 50 judges whether or not the fresh air compensation acceleration request flag is ON. When the fresh air compensation acceleration request flag is ON (Yes), the control device 50 proceeds to step S080, and when it is not ON (No), the control device 50 ends the process shown in Fig. 2. When the process shown in Fig. 2 is ended as a result of the judgment in step S075 being (No), the control of the opening degree of the EGR valve is feedback-controlled so as to approach the target EGR rate in "Control of the EGR valve during steady operation" in Fig. 3 described later.

[0062] When the process proceeds to step S080, the control device 50 determines whether the EGR amount reduction flag is ON. If the EGR amount reduction flag is ON (Yes), the control device 50 proceeds to step S085, and if not (No), the control device 50 proceeds to step S090.

[0063] When the process proceeds to step S085, the control device 50 obtains an amount of decrease in the EGR opening degree corresponding to the operating state, controls the EGR valve opening degree to be forcibly and quickly decreased to an opening degree obtained by subtracting the amount of decrease in the EGR opening degree from the current opening degree of the EGR valve, and ends the process shown in Fig. 2. Note that instead of decreasing the opening degree by the amount of decrease in the EGR opening degree, the EGR valve opening degree may be fully closed.

[0064] When the process proceeds to step S090, the control device 50 controls the opening degree of the EGR valve so as to maintain (hold) the current opening degree of the EGR valve, and ends the process shown in Fig. 2. In this case, the opening degree of the EGR valve that was reduced in step S085 is maintained, and therefore the forcibly reduced opening degree is maintained.

[0065] Next, an example of [EGR valve control during steady operation] shown in Fig. 3 will be described. The control device 50 (CPU 51) starts [EGR valve control during steady operation] shown in Fig. 3 at a predetermined time interval (several [ms] to several tens of [ms]), for example, and advances the process to step SE010.

[0066] In step SE010, the control device 50 determines whether the fresh air compensation acceleration request flag is OFF. If the fresh air compensation acceleration request flag is OFF (Yes), the control device 50 proceeds to step SE020. If not (No), the control device 50 ends the process shown in FIG. 3 and does not control the opening of the EGR valve in the process shown in FIG.

[0067] When the process proceeds to step SE020, the control device 50 executes control of the opening degree of the existing EGR valve and ends the process shown in Fig. 3. For example, the control device 50 calculates a target EGR rate (the amount of EGR gas relative to the amount of intake air in the cylinder (amount of fresh intake air + amount of EGR gas)) based on the operating state of the internal combustion engine, and feedback-controls the opening degree of the EGR valve so that the actual EGR rate approaches the target EGR rate.

[0068] [Comparison of an example of the operation of the first embodiment (FIG. 4) with the operation of a conventional system that does not forcibly reduce the EGR valve (FIG. 5)] The example shown in Fig. 4 shows an example of the operation of the first embodiment based on the processing of the flowcharts shown in Fig. 2 and Fig. 3. In the example shown in Fig. 4, the driver lightly depresses the accelerator pedal to drive at a low speed before time T1, but suddenly depresses the accelerator pedal just before time T1 to request acceleration.

[0069] In the example of Figure 4, the acceleration period Tacc1, which is the period from time T1 to time T4, indicates the acceleration period of the vehicle, and the fresh air replenishment acceleration request period Tair, which is the period from time T1 to time T3 (the period when the ``fresh air replenishment acceleration request flag'' is ON), corresponds to the fresh air replenishment acceleration request period.

[0070] [Behavior in the period before time T1] First, the operation in the period before time T1 will be described. Before time T1, the driver slightly depresses the accelerator pedal and drives at a low speed. At this time, as shown in FIG. 4, the "accelerator opening" is low and almost constant, and the "vehicle speed" is also low and almost constant. In addition, the "target boost pressure (pimtrg_1)", "realizable target boost pressure (pimtrg_2)", and "actual boost pressure" in the "boost pressure" are also low and almost constant. For this reason, the "boost pressure deviation (pimdlt)" and "Δpimdlt" are almost zero, and the "realizable target driving energy (etintrg)" and "actual driving energy (etin)" in the "driving energy" are also low and almost constant.

[0071] In addition, both the "fresh air compensation acceleration request flag" and the "EGR amount reduction flag" are set to OFF, and the EGR valve opening is feedback-controlled in step SE020 shown in Fig. 3. In this case, the "EGR valve opening" is controlled to a relatively large opening so as to approach the target EGR rate, and a relatively large amount of EGR gas is mixed into the intake air. For this reason, the "amount of exhaust NOx (instantaneous value)" is low, and the slope of the "amount of exhaust NOx (accumulated value)" is also gentle.

[0072] [Operation during the period from just before time T1 to time T2] Next, the operation in the period from immediately before time T1 to time T2 will be described. The period from time T1 to time T2 is the period of "Δpimdlt≧C1" in "Δpimdlt" in FIG. 4. The driver suddenly and greatly depresses the accelerator pedal immediately before time T1 to request acceleration, and the "accelerator opening" rises suddenly and greatly. As a result, the "target boost pressure (pimtrg_1)" in the "boost pressure" also rises suddenly and greatly from immediately before time T1. The "realizable target boost pressure (pimtrg_2)" and the "actual boost pressure" rise more slowly compared to the "target boost pressure (pimtrg_1)", and the "actual boost pressure" is lower than the "realizable target boost pressure (pimtrg_2)".

[0073] The "supercharging pressure deviation (pimdlt)" is the "target supercharging pressure (pimtrg_1)" - the "actual supercharging pressure", and rises sharply immediately before time T1 and then gradually decreases as the "actual supercharging pressure" rises. Therefore, the slope of the "supercharging pressure deviation (pimdlt)", "Δpimdlt", rises sharply immediately before time T1 and then falls sharply. The period when "Δpimdlt" ≧ C1 is the period from time T1 to time T2.

[0074] The "realizable target driving energy (etintrg)" in the "driving energy" rises gradually, similar to the "realizable target boost pressure (pimtrg_2)" in the "boost pressure". Also, the "actual driving energy (etin)" in the "driving energy" rises gradually, similar to the "actual boost pressure" in the "boost pressure", and the "actual driving energy (etin)" is lower than the "realizable target driving energy (etintrg)".

[0075] During the period from time T1 to time T2, Δpimdlt≧C1, so the "fresh air compensation acceleration request flag" and the "EGR amount reduction flag" are both set to ON. Therefore, the "EGR valve opening" is forcibly and quickly reduced, and a shortage of the fresh air intake amount is avoided. In addition, the "emission NOx amount (instantaneous value)" increases, and the slope of the "emission NOx amount (integrated value)" also becomes large.

[0076] [Operation during the period from time T2 to time T3] Next, the operation during the period from time T2 to time T3 will be described. The timing of time T3 is the timing when "actual driving energy (etin)≧realizable target driving energy (etintrg)" in "driving energy". During the period from time T2 to time T3, "accelerator opening" is held constant, and the driver continues to request acceleration. Also, "target boost pressure (pimtrg_1)" in "boost pressure" is held at a substantially constant value, and "realizable target boost pressure (pimtrg_2)" and "actual boost pressure" are gradually increasing.

[0077] The "supercharging pressure deviation (pimdlt)" gradually decreases as the "actual supercharging pressure" gradually increases. Therefore, "Δpimdlt", which is the slope of the "supercharging pressure deviation (pimdlt)", has a negative value, and Δpimdlt < C1.

[0078] The "achievable target driving energy (etintrg)" in "driving energy" gradually rises, similar to the "achievable target supercharging pressure (pimtrg_2)" in "supercharging pressure". Also, the "actual driving energy (etin)" in "driving energy" gradually rises, similar to the "actual supercharging pressure" in "supercharging pressure". The "actual driving energy (etin)" is lower than the "achievable target driving energy (etintrg)", and at time T3, "actual driving energy (etin) ≥ achievable target driving energy (etintrg)".

[0079] At time T3 when "actual driving energy (etin) ≥ achievable target driving energy (etintrg)", the "fresh air replenishment acceleration request flag" is set to OFF. During the period from time T2 to time T3, since Δpimdlt < C1, the "EGR reduction flag" is set to OFF. Therefore, during the period from time T2 to time T3, the "EGR valve opening" maintains (holds) the previous EGR valve opening, maintains (holds) the state of being forcibly reduced, and avoids the shortage of fresh air intake. Also, the increasing state of the "exhaust NOx amount (instantaneous value)" is maintained (continued), and the slope of the "exhaust NOx amount (integrated value)" also remains in a large state (continued).

[0080] [Operation during the period from time T3 to time T4] Next, the operation during the period from time T3 to time T4 will be described. The timing of time T4 is the timing when the "vehicle speed", which has been increasing in response to the driver's acceleration request, reaches a constant vehicle speed and the vehicle acceleration is completed, and is different from the timing when the "fresh air compensation acceleration request flag" ends (OFF). During the period from time T3 to time T4, the "accelerator opening" is held constant and the driver's acceleration request continues. Also, the "target boost pressure (pimtrg_1)" in the "boost pressure" is held at a substantially constant value, the "realizable target boost pressure (pimtrg_2)" is rising slowly, and the "actual boost pressure" rises slowly and then drops slightly to approach the target boost pressure.

[0081] The "supercharging pressure deviation (pimdlt)" gradually decreases with the gradual increase in the "actual boost pressure", then gradually increases and approaches zero, and the slope of the "supercharging pressure deviation (pimdlt)", "Δpimdlt", approaches zero from a negative value, and Δpimdlt <C1となっている。

[0082] The "realizable target driving energy (etintrg)" in the "driving energy" increases gradually, similar to the "realizable target boost pressure (pimtrg_2)" in the "boost pressure". Also, the "actual driving energy (etin)" in the "driving energy" increases gradually, similar to the "actual boost pressure" in the "boost pressure", and then drops slightly to approach the realizable target driving energy. The "actual driving energy (etin)" is higher than the "realizable target driving energy (etintrg)", and at time T4, the "actual driving energy (etin) ≒ realizable target driving energy (etintrg)".

[0083] In the period from time T3 to time T4, the "fresh air compensation acceleration request flag" and the "EGR amount reduction flag" are both set to OFF. Therefore, the "EGR valve opening" is feedback controlled to approach the target EGR rate in the processing of step SE020 shown in Fig. 3. As a result, the "emission NOx amount (instantaneous value)" gradually decreases according to the operation of the EGR valve opening, and the slope of the "emission NOx amount (integrated value)" also gradually becomes smaller.

[0084] [Behavior after time T4] Next, the operation after time T4 will be described. After time T4, the "accelerator opening" is kept constant, but the vehicle has completed acceleration. Also, the "target boost pressure (pimtrg_1)", "realizable target boost pressure (pimtrg_2)", and "actual boost pressure" in the "boost pressure" are almost the same value.

[0085] "Supercharging pressure deviation (pimdlt)" and "Δpimdlt", which is the slope of "Supercharging pressure deviation (pimdlt)", are both almost zero, and Δpimdlt <C1となっている。

[0086] In addition, the "realizable target driving energy (etintrg)" and "actual driving energy (etin)" in "driving energy" are almost the same value.

[0087] After time T4, both the "fresh air compensation acceleration request flag" and the "EGR amount reduction flag" are set to OFF, and the "EGR valve opening" is feedback-controlled to approach the target EGR rate in the process of step SE020 shown in Fig. 3. As a result, the "emission NOx amount (instantaneous value)" is maintained at a value that has decreased in accordance with the operation of the EGR valve opening, and the slope of the "emission NOx amount (accumulated value)" is also maintained at a small slope.

[0088] For example, even if the accelerator pedal depression speed is the same, when the vehicle speed is relatively high, the amount of fresh air intake may not be insufficient compared to when the vehicle speed is relatively low. If the EGR valve is fully closed based on the accelerator pedal depression speed, the EGR valve may be fully closed even if the amount of fresh air intake is not insufficient, and the amount of NOx generated may be increased unnecessarily. However, in the first embodiment of the present application, whether or not an acceleration request (a fresh air compensation acceleration request) in which the amount of fresh air intake of the internal combustion engine is insufficient is determined based on the supercharging-related amount (in this case, Δpimdlt), so that it is possible to more appropriately determine whether or not the acceleration request is insufficient in the amount of fresh air intake compared to when it is determined based on the accelerator pedal depression speed. Therefore, it is possible to appropriately avoid an unnecessary increase in the amount of NOx generated.

[0089] In addition, in the case of conventional control in which the full closure control of the EGR valve is released when the depression amount of the accelerator pedal is returned to a predetermined amount, the period of full closure control of the EGR valve is long, and there are cases in which the amount of NOx generated increases unnecessarily. However, in the first embodiment of the present application, whether or not the fresh air compensation acceleration request has ended is determined based on the supercharging-related amount (in this case, when the actual driving energy is equal to or greater than the feasible target driving energy), so the end of the fresh air compensation acceleration request can be determined at a more appropriate timing that is neither too early nor too late, compared to when it is determined based on the depression amount of the accelerator pedal. Therefore, an unnecessary increase in the amount of NOx generated can be appropriately avoided.

[0090] [Comparison with the operation of a conventional system that does not forcibly reduce the EGR valve (Fig. 5)] FIG. 5 shows an example of the operation when the driver makes the same acceleration request as in FIG. 4 in the "conventional system that does not forcibly reduce the EGR valve when acceleration is requested." The "accelerator opening" in FIG. 5 is the same as the "accelerator opening" in FIG. 4, and the "target boost pressure" in "boost pressure" in FIG. 5 is the same as the "target boost pressure (pimtrg_1)" in "boost pressure" in FIG. 4. In addition, in the conventional system shown in FIG. 5, compared to FIG. 4, the "realizable target boost pressure," "boost pressure deviation," "Δpimdlt," "realizable target driving energy" and "actual driving energy" in "driving energy," "fresh air compensation acceleration request flag," and "EGR reduction flag" are not calculated (not set), so are not shown.

[0091] In the conventional system shown in FIG. 5, the "EGR valve opening" is gradually reduced by feedback control in the period from time T1Z to time T2Z when the "accelerator opening" rises significantly and an acceleration request is initiated. However, the reduction speed is very slow compared to the reduction speed of the "EGR valve opening" from time T1 to time T2 shown in FIG. 4. Therefore, in the conventional system shown in FIG. 5, a shortage of the fresh air intake occurs immediately after time T1Z when the acceleration request is initiated, and acceleration performance deteriorates. However, in the first embodiment shown in FIG. 4, the "EGR valve opening" is forcibly and instantly reduced in the short period from time T1 to time T2 when it is determined that a fresh air supplement acceleration request has occurred, thereby avoiding a shortage of the fresh air intake.

[0092] Since the shortage of the fresh air intake amount can be avoided, the delay time Tdly1 until the "vehicle speed" starts to increase in the first embodiment shown in FIG. 4 is shorter than the delay time TdlyZ until the "vehicle speed" starts to increase in the conventional system shown in FIG. 5. Therefore, the first embodiment shown in FIG. 4 suppresses the deterioration of acceleration. Also, since the first embodiment shown in FIG. 4 avoids the shortage of the fresh air intake amount during acceleration, the inclination angle of the increase of the "actual boost pressure" in the "boost pressure" and the inclination angle of the increase of the "vehicle speed" are larger than those of the conventional system shown in FIG. 5, and the deterioration of acceleration is suppressed. Therefore, the acceleration period Tacc1 (not the fresh air compensation acceleration request period Tair) from the start to the end of the acceleration of the vehicle in the first embodiment shown in FIG. 4 is shorter than the acceleration period TaccZ in the conventional system shown in FIG. 5, and the deterioration of acceleration is suppressed. Also, although not shown, the first embodiment shown in FIG. 4 avoids the shortage of the fresh air intake amount during acceleration, and the generation of smoke is also suppressed.

[0093] Also, the maximum value Vnox1 of the "amount of exhausted NOx (instantaneous value)" during the acceleration period Tacc1 in the first embodiment shown in Fig. 4 is slightly larger than the maximum value VnoxZ of the "amount of exhausted NOx (instantaneous value)" during the acceleration period TaccZ in the conventional system shown in Fig. 5 (because the EGR valve is forcibly reduced). However, since the acceleration period Tacc1 in the first embodiment shown in Fig. 4 is shorter than the acceleration period TaccZ in the conventional system shown in Fig. 5, the "amount of exhausted NOx (integrated value)" during the acceleration period, Qnox1 shown in Fig. 4, is equal to or smaller than QnoxZ shown in Fig. 5.

[0094] In the first embodiment shown in FIG. 4, even if the "accelerator opening" is in the same starting state, the actual boost pressure, the target boost pressure, and the like are different due to the difference in the operating state between the case where an acceleration request is made while traveling at a low vehicle speed (and low revolutions) and the case where an acceleration request is made while traveling at a high vehicle speed (and medium to high revolutions). Therefore, the boost-related amount (boost pressure deviation, Δpimdlt, and fresh air compensation acceleration request determination threshold C1) are also different. For this reason, for example, when the amount of fresh air intake is insufficient in an acceleration request from a low vehicle speed, it is appropriately determined that a fresh air compensation acceleration request has occurred, and when the amount of fresh air intake is not insufficient in an acceleration request from a high vehicle speed, it is appropriately determined that a fresh air compensation acceleration request has not occurred. That is, in the case of an acceleration request in which the amount of fresh air intake is not insufficient, it is appropriately determined that a fresh air compensation acceleration request has not occurred, and the opening of the EGR valve is not forcibly reduced unnecessarily, so that an unnecessary increase in NOx can be suppressed.

[0095] In a conventional system (not shown) that determines whether the acceleration request is one that will cause a shortage of fresh air intake based on the accelerator opening state (accelerator operation speed, etc.) when the driver requests acceleration, and reduces the opening of the EGR valve when it is determined that the fresh air intake amount is insufficient, cannot distinguish between a case where the acceleration request is made while driving at a low vehicle speed (and low revolutions) and a case where the acceleration request is made while driving at a high vehicle speed (and medium to high revolutions) when the same "accelerator opening" is in a rising state. In other words, when the acceleration request is made from a high vehicle speed, the opening of the EGR valve is reduced even though the fresh air intake amount is not actually insufficient, which may cause an unnecessary increase in NOx. However, in the first embodiment of the present application, it is determined whether the acceleration request is one that will cause a shortage of fresh air intake based on the supercharging-related amount (supercharging pressure deviation, Δpimdlt, and fresh air compensation acceleration request determination threshold C1), so that even in the above example, it is possible to appropriately distinguish and determine whether the acceleration request is one that will cause a shortage of fresh air intake amount.

[0096] In the first embodiment shown in FIG. 4, the end of the fresh air compensation acceleration request is determined based on the supercharging-related amount (realizable target driving energy based on the realizable target supercharging pressure, actual driving energy, etc.), so that the end of the fresh air compensation acceleration request can be determined at an appropriate timing, not too early and not too late, before the actual supercharging pressure reaches the target supercharging pressure, without returning the accelerator opening. This makes it possible to suppress an unnecessary increase in NOx. Since the end of the fresh air compensation acceleration request is determined taking into account environmental conditions such as intake temperature and coolant temperature, and parameters used to calculate the driving energy of the supercharger (EGR gas amount, exhaust temperature, exhaust gas amount, etc.), EGR control can be resumed at the earliest possible time (EGR valve control is returned to feedback control from forced reduction), so that acceleration performance can be further improved while suppressing the "NOx emission (integrated value)" to a level lower than that of the conventional system in FIG. 5.

[0097] [Processing procedure of the control device 50 according to the second embodiment (FIG. 6)] Next, an example of the processing procedure of the control device 50 in the second embodiment will be described with reference to the flowchart shown in Fig. 6. The flowchart of the second embodiment shown in Fig. 6 differs from the flowchart of the first embodiment shown in Fig. 2 in that step S040 is omitted and the determination in step S065 is changed to a determination in step S065B. The following mainly describes the differences. Note that the explanation of the omission of step S040 will be omitted.

[0098] In step S065B, the control device 50 determines whether the actual boost pressure is equal to or greater than the realizable target boost pressure (pimtrg_2). If the actual boost pressure is equal to or greater than the realizable target boost pressure (pimtrg_2) (Yes), the control device 50 proceeds to step S070, and if not (No), the control device 50 proceeds to step S075.

[0099] In step S065 in Fig. 2, it is determined whether the actual driving energy (etin) is equal to or greater than the realizable target driving energy (etintrg), but in step S065B in Fig. 6, it is determined whether the actual boost pressure is equal to or greater than the realizable target boost pressure (pimtrg_2). In this case, since it is not necessary to calculate the actual driving energy (etin) or the realizable target driving energy (etintrg), the processing load on the CPU 51 is reduced.

[0100] Also, the example of operation is similar to that of the first embodiment shown in FIG. 4, and the position of time T2 (the position where the actual driving energy ≧ the feasible target driving energy in “driving energy”) is changed to the position where the actual boost pressure ≧ the feasible target boost pressure in “boost pressure”, but it is approximately the same position.

[0101] The control device 50 (CPU 51) which executes the processing of steps S010 to S030 and steps S045 to S055 of the first embodiment shown in FIG. 2 and the second embodiment shown in FIG. 6 corresponds to a fresh air compensation acceleration request occurrence determination unit 51A (see FIG. 1) which determines that a fresh air compensation acceleration request has not occurred if it determines that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including input of an acceleration request from the driver, and determines that a fresh air compensation acceleration request has occurred if it determines that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is insufficient.

[0102] In addition, the control device 50 (CPU 51) executing the processing of steps S035, (step S040) and steps S060 to S070 in the first embodiment shown in Figure 2 and the second embodiment shown in Figure 6 corresponds to a fresh air supplementation acceleration request end determination unit 51B (see Figure 1) that determines whether or not the fresh air supplementation acceleration request has ended based on the supercharging-related amount.

[0103] In addition, the control device 50 (CPU 51) executing the processing of steps S075 to S090 in the first embodiment shown in Figure 2 and the second embodiment shown in Figure 6 corresponds to an EGR reduction unit 51C (see Figure 1) at the time of fresh air replenishment acceleration request, which forcibly reduces the opening of the EGR valve during the fresh air replenishment acceleration request period from when it is determined that a fresh air replenishment acceleration request has occurred to when it is determined that the fresh air replenishment acceleration request has ended.

[0104] The control device 50 of the internal combustion engine system of the present invention is not limited to the configuration, processing procedures (flowcharts), etc. described in this embodiment, and various modifications, additions, and deletions are possible without departing from the spirit of the present invention.

[0105] In the description of this embodiment, an example has been described in which whether or not a fresh air compensation acceleration request has occurred is determined based on the amount of change (Δpimdlt) over time in the boost pressure deviation (pimdlt) between the target boost pressure and the actual boost pressure, but the determination may be based on other boost-related quantities (e.g., a required fresh air amount, etc.) related to boost. Also, in the description of this embodiment, an example has been described in which the value of the fresh air compensation acceleration request determination threshold C1 is changed depending on the operating state, but the value of the fresh air compensation acceleration request determination threshold C1 may be a constant.

[0106] In addition, the calculation method of the achievable target boost pressure, the achievable target drive energy, and the actual drive energy is not limited to the example described in this embodiment, and may be calculated in any manner. Furthermore, the determination of the end of the fresh air compensation acceleration request is not limited to the determination method described in this embodiment. For example, the end of the fresh air compensation acceleration request may be determined when the actual boost pressure almost matches the target boost pressure.

[0107] In the embodiment, the opening of the EGR valve is forcibly decreased during the period when the fresh air refill acceleration request is generated, but the opening of the EGR valve may be fully closed during this period. Also, in the embodiment, the opening of the EGR valve is maintained (kept) during the period when the fresh air refill acceleration request is not generated, but the opening of the EGR valve may be gradually decreased or gradually increased depending on the operating state.

[0108] In the description of the present embodiment, a turbocharger equipped with a variable nozzle has been taken as an example, but a turbocharger equipped with a wastegate valve may also be used. Also, in the description of the present embodiment, a turbocharger having a turbine and a compressor (driving energy is exhaust energy) has been taken as an example of a supercharger, but an electric supercharger having an electric motor and a compressor (driving energy is electrical energy) or a supercharger (driving energy is the rotational energy of a crankshaft) may also be used.

[0109] Furthermore, the control device for an internal combustion engine of the present invention is not limited to diesel engines, but can also be applied to gasoline engines.

[0110] Additionally, greater than or equal to (≧), less than or equal to (≦), larger than (>), less than (<), etc. may or may not include an equal sign. [Explanation of symbols]

[0111] 1 Internal Combustion Engine System 10 Internal combustion engine 11A, 11B Intake pipe 11C Intake manifold 12A Exhaust manifold 12B, 12C exhaust pipe 13 EGR piping 13B Bypass piping 14 EGR valve 14B Regulating valve 15 EGR cooler 16 Intercooler 21 Intake volume detection device 22A Crank angle detector 22B Cam angle detector 23 Atmospheric pressure detector 24A Compressor upstream pressure detector 24B Compressor downstream pressure detector 24C Boost pressure detector 25 Accelerator pedal depression amount detection device 26A Turbine upstream pressure detector 26B Turbine downstream pressure detection device 26C Exhaust manifold pressure detector 27 Vehicle speed detection device 28A, 28B Intake air temperature detector 28C Coolant temperature detector 29 Exhaust temperature detector 29AF Air-fuel ratio detector 30 Turbocharger 31 Nozzle drive unit 32 Nozzle closure detection device 33 Variable Nozzle 35 Compressor 36 Turbine 41 Common Rail 43A~43D Injectors 45A~45D Cylinder 47 Throttle device 47S Throttle opening detector 47V throttle valve 50 Control device 51 CPU 51A Fresh air replenishment acceleration request occurrence determination unit 51B Fresh air replenishment acceleration request end determination unit 51C EGR reduction section when fresh air supplement acceleration is required 52 RAM 53 Storage device 54 Timer 61 Exhaust purification device 72 Fuel Pump 73 Fuel pressure detection device Tacc1 acceleration period Tair New Air Compensation Acceleration Request Period

Claims

1. A control device for an internal combustion engine system, The internal combustion engine system includes: An internal combustion engine; an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine; A supercharger that supercharges the intake air of the internal combustion engine; a control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state; It has The control device includes: a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred when it is determined that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including an input of an acceleration request from a driver, and determines that the fresh air compensation acceleration request has occurred when it is determined that the acceleration request is one in which the fresh air intake amount is insufficient; a fresh air compensation acceleration request end determination unit that determines whether or not the acceleration request has ended after transitioning from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient based on the supercharging-related amount; an EGR amount reducing unit at the time of fresh air compensation acceleration request, which forcibly reduces an opening degree of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred until when it is determined that the acceleration request has ended; having The control device includes: when the fresh air compensation acceleration request occurrence determination unit determines whether or not the acceleration request is one in which the fresh air intake amount is insufficient based on the supercharging-related amount, A boost pressure deviation is calculated by subtracting an actual boost pressure, which is an actual boost pressure of the internal combustion engine, from a target boost pressure, which is a target boost pressure of the internal combustion engine calculated based on the operating state; a fresh air compensation acceleration request is determined to have occurred when a fluctuation amount of the supercharging pressure deviation with respect to time, the fluctuation amount being obtained by subtracting the previous supercharging pressure deviation from the current supercharging pressure deviation, becomes equal to or greater than a fresh air compensation acceleration request determination threshold value; A control device for an internal combustion engine system.

2. 2. The control device for an internal combustion engine system according to claim 1, The control device includes: The fresh air compensation acceleration request occurrence determination unit calculates the fresh air compensation acceleration request determination threshold value based on the operating state. A control device for an internal combustion engine system.

3. 3. The control device for an internal combustion engine system according to claim 1, The control device includes: When the fresh air supplement acceleration request end determination unit determines whether the acceleration request has ended, a realizable target supercharging pressure, which is a supercharging pressure for determining the end of an acceleration request after transition from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient, is calculated based on the operating state and a map in which the realizable target supercharging pressure corresponding to the operating state is set, or is calculated using each parameter of the operating state; determining that the acceleration request has ended when an actual boost pressure, which is an actual boost pressure of the internal combustion engine, becomes equal to or higher than the feasible target boost pressure; or, a realizable target supercharging pressure, which is a supercharging pressure for determining the end of an acceleration request after transition from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient, is calculated based on the operating state and a map in which the realizable target supercharging pressure corresponding to the operating state is set, or is calculated using each parameter of the operating state; calculating a realizable target drive energy, which is a supercharger drive energy predicted to be required to be input to the supercharger in order to set the supercharging pressure to the realizable target supercharging pressure, and which is for determining the end of an acceleration request after transition from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient, based on a map in which the supercharger drive energy corresponding to the supercharging pressure and the operating state is set, the realizable target supercharging pressure, and the operating state, or by using each parameter of the realizable target supercharging pressure and the operating state; determining that the acceleration request has ended when actual driving energy, which is supercharger driving energy actually input to the supercharger and is calculated using each parameter of the operating state, becomes equal to or greater than the feasible target driving energy; A control device for an internal combustion engine system.

4. The control device for an internal combustion engine system according to any one of claims 1 to 3, The control device includes: the fresh air compensation acceleration request time EGR amount reducing unit reduces an opening degree of the EGR valve in accordance with the operating state during an acceleration request period in which the fresh air intake amount is insufficient during the fresh air compensation acceleration request period; A control device for an internal combustion engine system.

5. The control device for an internal combustion engine system according to any one of claims 1 to 4, The control device includes: the fresh air compensation acceleration request time EGR amount reducing unit maintains the opening degree of the EGR valve that was reduced during the acceleration request period in which the fresh air intake amount is insufficient during the fresh air compensation acceleration request period in which the acceleration request period in which the fresh air intake amount is not insufficient. A control device for an internal combustion engine system.

6. A control device for an internal combustion engine system, The internal combustion engine system includes: An internal combustion engine; an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine; A supercharger that supercharges the intake air of the internal combustion engine; a control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state; It has The control device includes: a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred when it is determined that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including an input of an acceleration request from a driver, and determines that the fresh air compensation acceleration request has occurred when it is determined that the acceleration request is one in which the fresh air intake amount is insufficient; a fresh air compensation acceleration request end determination unit that determines whether or not the acceleration request has ended after transitioning from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient based on the supercharging-related amount; an EGR amount reducing unit at the time of fresh air compensation acceleration request, which forcibly reduces an opening degree of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred until when it is determined that the acceleration request has ended; having The control device includes: When the fresh air supplement acceleration request end determination unit determines whether the acceleration request has ended, a realizable target supercharging pressure, which is a supercharging pressure for determining the end of an acceleration request after transition from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient, is calculated based on the operating state and a map in which the realizable target supercharging pressure corresponding to the operating state is set, or is calculated using each parameter of the operating state; determining that the acceleration request has ended when an actual boost pressure, which is an actual boost pressure of the internal combustion engine, becomes equal to or higher than the feasible target boost pressure; or, a realizable target supercharging pressure, which is a supercharging pressure for determining the end of an acceleration request after transition from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient, is calculated based on the operating state and a map in which the realizable target supercharging pressure corresponding to the operating state is set, or is calculated using each parameter of the operating state; calculating a realizable target drive energy, which is a supercharger drive energy predicted to be required to be input to the supercharger in order to set the supercharging pressure to the realizable target supercharging pressure, and which is for determining the end of an acceleration request after transition from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient, based on a map in which the supercharger drive energy corresponding to the supercharging pressure and the operating state is set, the realizable target supercharging pressure, and the operating state, or by using each parameter of the realizable target supercharging pressure and the operating state; determining that the acceleration request has ended when actual driving energy, which is supercharger driving energy actually input to the supercharger and is calculated using each parameter of the operating state, becomes equal to or greater than the feasible target driving energy; A control device for an internal combustion engine system.

7. A control device for an internal combustion engine system, The internal combustion engine system includes: An internal combustion engine; an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine; A supercharger that supercharges the intake air of the internal combustion engine; a control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state; It has The control device includes: a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred when it is determined that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including an input of an acceleration request from a driver, and determines that the fresh air compensation acceleration request has occurred when it is determined that the acceleration request is one in which the fresh air intake amount is insufficient; a fresh air compensation acceleration request end determination unit that determines whether or not the acceleration request has ended after transitioning from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient based on the supercharging-related amount; an EGR amount reducing unit at the time of fresh air compensation acceleration request, which forcibly reduces an opening degree of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred until when it is determined that the acceleration request has ended; having The control device includes: the fresh air compensation acceleration request time EGR amount reducing unit reduces an opening degree of the EGR valve in accordance with the operating state during an acceleration request period in which the fresh air intake amount is insufficient during the fresh air compensation acceleration request period; A control device for an internal combustion engine system.

8. A control device for an internal combustion engine system, The internal combustion engine system includes: An internal combustion engine; an EGR valve that adjusts an EGR amount that returns a portion of the exhaust gas of the internal combustion engine to an intake air of the internal combustion engine; A supercharger that supercharges the intake air of the internal combustion engine; a control device that detects an operating state of the internal combustion engine and controls the internal combustion engine based on the operating state; It has The control device includes: a fresh air compensation acceleration request occurrence determination unit that determines that a fresh air compensation acceleration request has not occurred when it is determined that the acceleration request is one in which the fresh air intake amount of the internal combustion engine is not insufficient based on a supercharging-related amount related to supercharging in the operating state of the internal combustion engine including an input of an acceleration request from a driver, and determines that the fresh air compensation acceleration request has occurred when it is determined that the acceleration request is one in which the fresh air intake amount is insufficient; a fresh air compensation acceleration request end determination unit that determines whether or not the acceleration request has ended after transitioning from an acceleration request in which the fresh air intake amount is insufficient to an acceleration request in which the fresh air intake amount is not insufficient based on the supercharging-related amount; an EGR amount reducing unit at the time of fresh air compensation acceleration request, which forcibly reduces an opening degree of the EGR valve during a fresh air compensation acceleration request period from when it is determined that the fresh air compensation acceleration request has occurred until when it is determined that the acceleration request has ended; having The control device includes: the fresh air compensation acceleration request time EGR amount reducing unit maintains the opening degree of the EGR valve that was reduced during the acceleration request period in which the fresh air intake amount is insufficient during the fresh air compensation acceleration request period in which the acceleration request period in which the fresh air intake amount is not insufficient. A control device for an internal combustion engine system.

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