JP2020133415A - Control device for internal combustion engine - Google Patents

Abstract

To provide a control device for an internal combustion engine that enables a user to feel desired appropriate deceleration when the user releases an accelerator pedal for deceleration, in an internal combustion engine including a supercharger with a variable nozzle.SOLUTION: A control device includes: accelerator return state calculation means for calculating an accelerator return state that is a release state of an accelerator pedal during deceleration in which the accelerator pedal is released on the basis of a detection signal from accelerator pedal depression amount detection means; target engine braking force related information calculation means for calculating target engine braking force related information that is a target value of information related to engine braking force of an internal combustion engine based on the accelerator return state during deceleration; and deceleration time variable nozzle opening adjustment means for adjusting the engine braking force of the internal combustion engine by adjusting an opening of the variable nozzle to the closing side on the basis of the target engine braking force related information during deceleration and thus increasing exhaust pressure in an exhaust manifold.SELECTED DRAWING: Figure 6

Description

The present invention relates to an internal combustion engine control device that controls an internal combustion engine system having a supercharger equipped with a variable nozzle.

Some internal combustion engines installed in vehicles in recent years are equipped with a supercharger (so-called turbocharger) that supercharges using the energy of exhaust gas in order to obtain a larger output. The supercharger is provided with a variable nozzle so that the turbocharger can be efficiently supercharged even when the flow rate of the exhaust gas is small. Conventionally, in a vehicle equipped with an internal combustion engine system having a supercharger equipped with a variable nozzle, when the user depresses the accelerator pedal, a pleasant feeling of acceleration can be experienced. In recent years, in addition to this feeling of acceleration, it is desired that the user can experience an appropriate feeling of deceleration when the accelerator pedal is released.

For example, in Patent Document 1, in a hybrid vehicle having an engine having a turbocharger provided with a variable nozzle and a motor generator, the variable nozzle is fully opened at the time of deceleration to perform regenerative control (that is, braking at the time of deceleration). A method for controlling deceleration of a vehicle, which further improves the efficiency of regenerative energy, is disclosed.

Further, Patent Document 2 discloses a variable-capacity turbocharger including an inner peripheral scroll portion and an outer peripheral scroll portion, and a control valve controlled to be fully open or fully closed at the exhaust inlet portion of the outer peripheral scroll portion. It is described that a vehicle equipped with the variable capacity turbocharger can increase the back pressure of the internal combustion engine and secure good engine braking by controlling the control valve to the fully closed position when the vehicle decelerates.

Japanese Unexamined Patent Publication No. 2006-220045 Japanese Unexamined Patent Publication No. 2000-8868

The vehicle deceleration control method described in Patent Document 1 focuses on improving the regenerative energy efficiency, and when the user releases the accelerator pedal, the regenerative control may give a feeling of deceleration. It may be different from the appropriate deceleration feeling that the user expects depending on the pedal operation.

Further, in the variable capacity turbocharger described in Patent Document 2, the back pressure of the internal combustion engine is increased and engine braking force is generated by closing the outer peripheral scroll portion and using only the inner peripheral scroll portion when the vehicle is decelerated. .. However, since the exhaust inlet portion of the outer peripheral scroll portion can be controlled only to be fully open or fully closed, it is not possible to adjust to an appropriate deceleration feeling expected by the user according to the accelerator pedal operation.

The present invention has been devised in view of these points, and in an internal combustion engine system having a supercharger equipped with a variable nozzle, when the user decelerates by returning the accelerator pedal, the expected appropriate deceleration feeling is obtained. An object of the present invention is to provide a control device for an internal combustion engine that can be experienced.

In order to solve the above problems, the first invention of the present invention is a supercharger having a variable nozzle whose opening degree is adjusted according to an operating state of an internal combustion engine, and an accelerator pedal depression amount for detecting an accelerator pedal depression amount. An actuator including the variable nozzle is detected for an internal combustion engine system mounted on a vehicle having a detection means, and the operating state of the internal combustion engine including the accelerator pedal depression amount is detected, and based on the detected operating state. The supercharger has a turbine that rotates using the energy of exhaust gas, and the variable nozzle is transferred to the internal combustion engine according to the operating state of the internal combustion engine. The opening degree of the flow path that guides the exhaust gas can be adjusted, and the control device is based on the detection signal from the accelerator pedal depression amount detecting means, and the accelerator pedal that has been depressed is said to be decelerated when the accelerator pedal is returned. An accelerator return state calculating means for calculating the accelerator return state, which is the release state of the accelerator pedal, and a target value of information related to the engine braking force of the internal combustion engine based on the accelerator return state at the time of deceleration. A target engine braking force-related information calculating means for calculating engine braking force-related information, and an exhaust manifold that adjusts the opening degree of the variable nozzle to the closing side based on the target engine braking force-related information during deceleration. This is an internal combustion engine control device having a deceleration variable nozzle opening degree adjusting means that adjusts the engine braking force of the internal combustion engine by increasing the exhaust pressure of the internal combustion engine.

Next, the second invention of the present invention is the control device for the internal combustion engine according to the first invention, and the control device calculates the accelerator return state when the accelerator return state calculation means calculates the accelerator return state. This is an internal combustion engine control device that calculates the accelerator return state based on the depression amount reduction rate, which is the reduction rate of the accelerator pedal depression amount.

Next, the third invention of the present invention is the control device for the internal combustion engine according to the second invention, and the control device is the target engine calculated by the target engine braking force related information calculation means. The braking force-related information includes the target acceleration during deceleration, which is the target value of the acceleration on the deceleration side of the vehicle based on the accelerator release state, and the target acceleration during deceleration has a large reduction rate of the depression amount. Control of the internal combustion engine, which is set so as to be larger, and the increase rate of the target acceleration during deceleration is set to be larger than the increase rate of the depression amount reduction rate as the depression amount reduction rate is larger. It is a device.

Next, the fourth invention of the present invention is the control device for the internal combustion engine according to the third invention, and the target acceleration during deceleration further increases as the vehicle speed, which is the speed of the vehicle, increases. It is a control device of an internal combustion engine that is set to be.

Next, the fifth invention of the present invention is a control device for an internal combustion engine according to any one of the first to fourth inventions, and the internal combustion engine system has a plurality of the above-mentioned supercharging. A machine is mounted, and a switching means capable of switching the number of the superchargers to be operated from among the plurality of superchargers according to the operating state of the internal combustion engine is provided, and the control device is provided with a switching means. Based on the operating state of the internal combustion engine, it is possible to calculate the exhaust flow rate, which is the flow rate of the exhaust gas from the internal combustion engine, and the upper limit exhaust flow rate to each of the superchargers, and the variable nozzle is opened during deceleration. When the opening degree of the variable nozzle is adjusted by the degree adjusting means, when the exhaust flow rate to the supercharger being operated exceeds the upper limit exhaust flow rate, the supercharging that should be operated by controlling the switching means. It is an internal combustion engine control device that increases the number of machines and adjusts the opening degree of each of the variable nozzles of each of the operated superchargers to the closing side.

Next, the sixth invention of the present invention is a control device for an internal combustion engine according to any one of the first to fourth inventions, and the internal combustion engine system has a plurality of superchargings. A machine is mounted, and a switching means capable of switching the number of the superchargers to be operated from among the plurality of superchargers according to the operating state of the internal combustion engine is provided, and the control device is provided with a switching means. The upper limit rotation speed of each supercharger can be calculated based on the operating state of the internal combustion engine, and is operated when the opening degree of the variable nozzle is adjusted by the variable nozzle opening degree adjusting means during deceleration. When the number of revolutions of the turbocharger exceeds the upper limit of the number of revolutions, the number of the turbochargers to be operated by controlling the switching means is increased, and each of the turbochargers operated. It is an internal combustion engine control device that adjusts the opening degree of the variable nozzle to the closing side.

According to the first invention, at the time of deceleration, the target engine braking force related information is calculated based on the released state of the accelerator pedal, and the variable nozzle is controlled to the closing side based on the target engine braking force related information to exhaust. The exhaust pressure in the manifold is increased to increase the pump loss of the piston. As a result, the user can experience an appropriate deceleration feeling due to an appropriate engine brake when decelerating when the accelerator pedal is released. Further, by adjusting the opening degree of the variable nozzle, it is easy to make fine adjustments so that a desired engine braking force can be obtained.

According to the second invention, the feeling of deceleration expected by the user can be appropriately estimated by calculating the accelerator return state based on the depression amount reduction rate.

According to the third invention, the target engine braking force-related information includes the target acceleration during deceleration, which is the target value of the acceleration on the deceleration side of the vehicle based on the accelerator release state. Then, the magnitude of the deceleration target acceleration with respect to the magnitude of the depression amount reduction rate in the accelerator return state is not linear but non-linear, and the larger the depression amount reduction rate is, the increase rate of the deceleration target acceleration with respect to the increase rate of the depression amount reduction rate. Since it is set to be large, the user can experience a more sharp deceleration feeling.

According to the fourth invention, the target acceleration during deceleration is set to increase as the vehicle speed increases, so that the user feels an appropriate deceleration according to the vehicle speed when decelerating when the accelerator pedal is released. Can be experienced.

In the fifth invention, for example, in an internal combustion engine system having two superchargers, when only one supercharger is used, the flow rate of exhaust gas is large, and one supercharger has a variable nozzle. It may be predicted that durability etc. will be affected if the pressure is excessively squeezed to the closing side. In such a case, the number of turbochargers to be operated is increased (two turbochargers are operated), and the opening degree of the variable nozzle of each supercharger is adjusted. As a result, it is possible to prevent the reliability of the turbocharger from being affected.

In the sixth invention, for example, in an internal combustion engine system having two superchargers, when only one supercharger is used, the flow rate of exhaust gas is large and the rotation speed of the supercharger is very high. It is high, and in one supercharger, if the variable nozzle is further controlled to the closing side, it may be predicted that the rotation speed will reach the speed at which durability and the like are affected. In such a case, the number of turbochargers to be operated is increased (two turbochargers are operated), and the opening degree of the variable nozzle of each supercharger is adjusted. As a result, it is possible to prevent the reliability of the turbocharger from being affected.

It is a figure explaining the example of the whole schematic structure of the internal combustion engine system (internal combustion engine system including two superchargers) which has the control device of the internal combustion engine of this invention. It is a flowchart explaining an example of the processing procedure (the whole processing procedure) of the control device in 1st Embodiment. It is a flowchart explaining the example of the processing procedure (processing procedure of variable nozzle adjustment processing at the time of deceleration) of the control device in 1st Embodiment. In the first embodiment, it is the flowchart explaining the example of skipping the existing variable nozzle opening degree control when the engine brake request flag is ON. In the first embodiment, it is the flowchart explaining the example of skipping the existing supercharger switching control when the engine brake request flag is ON. In the first embodiment, an operation waveform explaining the calculation of the target torque during deceleration, the adjustment of the opening degree of the variable nozzle so as to approach the target torque during deceleration, and the like when the user decelerates by returning the accelerator pedal. is there. It is a figure explaining the example of the stepping amount reduction rate, the target acceleration characteristic at the time of deceleration in the 1st Embodiment. In the first embodiment, it is a figure explaining the example of the intake flow rate, the supercharging pressure / atmospheric pressure, and the upper limit rotation speed characteristic. In the second embodiment, it is the flowchart explaining the example of the processing procedure of the control device (processing procedure of variable nozzle adjustment processing at the time of deceleration). In the second embodiment, an operation waveform explaining the calculation of the target torque during deceleration, the adjustment of the opening degree of the variable nozzle so as to approach the target torque during deceleration, and the like when the user decelerates by returning the accelerator pedal. is there.

● [Example of the overall schematic configuration of the internal combustion engine system 1 (Fig. 1)]
Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. First, an example of an overall schematic configuration of an internal combustion engine system 1 having an internal combustion engine control device 70 will be described with reference to FIG. In the description of the present embodiment, an internal combustion engine 10 (for example, a diesel engine) mounted on a vehicle will be used as an example of the internal combustion engine. Further, in the example of the internal combustion engine system 1 shown in FIG. 1, two turbochargers, a first supercharger 31 and a second supercharger 32, are arranged in parallel, but the intake bypass pipe 11CB and the intake bypass valve By having 61, it is possible to supercharge the second supercharger 32 and the first supercharger 31 in series.

Hereinafter, the entire internal combustion engine system 1 will be described in order from the intake side (upper side of FIG. 1) to the exhaust side (lower side of FIG. 1) with reference to FIG. On the inflow side of the intake pipe 11A, an intake flow rate detecting means 21 (for example, an intake flow rate sensor), an atmospheric pressure detecting means 22D (for example, a pressure sensor), and an intake temperature detecting means 22E (for example, a temperature sensor) are provided. There is. The intake flow rate detecting means 21 outputs a detection signal according to the flow rate of the air sucked by the internal combustion engine 10 to the control device 70. The atmospheric pressure detecting means 22D outputs a detection signal corresponding to the atmospheric pressure (atmospheric pressure) of the atmosphere to the control device 70, and the intake air temperature detecting means 22E is the temperature of the air sucked by the internal combustion engine 10 (in the intake pipe 11A). A detection signal corresponding to the air temperature) is output to the control device 70. The outflow side of the intake pipe 11A is bifurcated into the intake pipes 11B1 and 11B2, and is connected to the inflow side of the intake pipe 11B1 and the inflow side of the intake pipe 11B2.

The outflow side of the intake pipe 11B1 is connected to the inflow side of the compressor 31A of the first supercharger 31 (first turbocharger). Further, the outflow side of the intake bypass pipe 11CB is connected in the middle of the intake pipe 11B1. The outflow side of the compressor 31A is connected to the inflow side of the intake pipe 11C1, and the outflow side of the intake pipe 11C1 is merged with the outflow side of the intake pipe 11C2 and connected to the inflow side of the intake pipe 11D. The compressor 31A is rotationally driven by a turbine 31B that rotates using the energy of the exhaust gas, compresses the air taken in from the intake pipe 11B1 and discharges (supercharges) it to the intake pipe 11C1.

The outflow side of the intake pipe 11B2 is connected to the inflow side of the compressor 32A of the second supercharger 32 (second turbocharger). The outflow side of the compressor 32A is bifurcated into the intake pipe 11C2 and the intake bypass pipe 11CB, and is connected to the inflow side of the intake pipe 11C2 and the inflow side of the intake bypass pipe 11CB. The outflow side of the intake pipe 11C2 merges with the outflow side of the intake pipe 11C1 and is connected to the inflow side of the intake pipe 11D. Further, the intake pipe 11C2 is provided with an intake switching valve 62 that opens and closes the intake pipe 11C2 based on a control signal from the control device 70. The outflow side of the intake bypass pipe 11CB is connected to the intake pipe 11B1. Further, the intake bypass pipe 11CB is provided with an intake bypass valve 61 that opens and closes the intake bypass pipe 11CB based on a control signal from the control device 70.

The turbine 32B that rotationally drives the compressor 32A is rotationally driven by the energy of the exhaust gas when the exhaust switching valve 63 is opened. The exhaust switching valve 63 opens and closes the exhaust pipe 12B2 based on the control signal from the control device 70. When the exhaust switching valve 63 is opened and the turbine 32B is rotationally driven, the control device 70 opens one of the intake switching valve 62 and the intake bypass valve 61 and closes the other. Further, when the exhaust switching valve 63 is closed, the control device 70 closes both the intake switching valve 62 and the intake bypass valve 61.

When the compressor 32A is rotationally driven by the turbine 32B, when the intake switching valve 62 is in the open state and the intake bypass valve 61 is in the closed state, the air sucked from the intake pipe 11B2 is compressed and discharged to the intake pipe 11C2 ( Supercharge). Further, when the compressor 32A is rotationally driven by the turbine 32B, when the intake switching valve 62 is in the closed state and the intake bypass valve 61 is in the open state, the air sucked from the intake pipe 11B2 is compressed to the intake bypass pipe 11CB. Discharge (supercharge).

The inflow side of the intake pipe 11D is connected to the outflow side of the intake pipe 11C1 and the outflow side of the intake pipe 11C2, and the outflow side of the intake pipe 11D is connected to the inflow side of the intake manifold 11E. In any one of the intake pipe 11C1, the intake pipe 11D, and the intake manifold 11E, which is on the downstream side of the compressor 31A of the first supercharger 31, the supercharging pressure detecting means 22A (for example, a pressure sensor) for detecting the supercharging pressure is used. ) Is provided. The supercharging pressure detecting means 22A outputs a detection signal corresponding to the pressure of the supercharged intake air to the control device 70.

The outflow side of the intake manifold 11E is connected to each cylinder of the internal combustion engine 10.

The internal combustion engine 10 has a plurality of cylinders, and injectors 43A to 43H are provided in each cylinder. Fuel is supplied to the injectors 43A to 43H from the common rail 42 via a fuel pipe, and the injectors 43A to 43H are driven by a control signal from the control device 70 to inject fuel into the respective cylinders.

Fuel is supplied to the common rail 42 from a fuel pressure adjusting pump 41 driven based on a control signal from the control device 70. Further, the common rail 42 is provided with a fuel pressure detecting means 23 (for example, a pressure sensor) for detecting the pressure of the fuel in the common rail 42. The fuel pressure detecting means 23 outputs a detection signal corresponding to the detected fuel pressure to the control device 70. The control device 70 controls the fuel pressure adjusting pump 41 so that the fuel pressure based on the detection signal from the fuel pressure detecting means 23 becomes the target fuel pressure.

The internal combustion engine 10 is provided with a rotation detecting means 25 (for example, a rotation sensor), a coolant temperature detecting means 24 (for example, a temperature sensor), and the like. The rotation detecting means 25 outputs a detection signal corresponding to the rotation speed of the crankshaft of the internal combustion engine 10 (that is, the engine rotation speed) to the control device 70. The coolant temperature detecting means 24 detects the temperature of the cooling coolant circulated in the internal combustion engine 10 and outputs a detection signal corresponding to the detected temperature to the control device 70.

The inflow side of the exhaust manifolds 12A1 and 12A2 is connected to the exhaust side of the internal combustion engine 10, the inflow side of the exhaust pipe 12B1 is connected to the outflow side of the exhaust manifold 12A1, and the inflow side of the exhaust pipe 12B2 is connected to the outflow side of the exhaust manifold 12A2. It is connected. The outflow side of the exhaust pipe 12B1 is connected to the inflow side of the turbine 31B of the first supercharger 31, and the outflow side of the exhaust pipe 12B2 is connected to the inflow side of the turbine 32B of the second supercharger 32. Further, the exhaust pipe 12B2 is provided with an exhaust switching valve 63 that opens and closes the exhaust pipe 12B2 based on a control signal from the control device 70. Further, the exhaust pipe 12B1 and the exhaust pipe 12B2 are connected to an exhaust bypass pipe 12BB that guides the exhaust gas in the exhaust pipe 12B2 to the exhaust pipe 12B1 when the exhaust switching valve 63 is in the closed state.

Further, the exhaust manifold 12A1 is provided with an exhaust pressure detecting means 22F (for example, a pressure sensor) for detecting the pressure of the exhaust in the exhaust manifold 12A1. The exhaust pressure detecting means 22F outputs a detection signal corresponding to the pressure of the exhaust gas in the exhaust manifold 12A1 to the control device 70. Similarly, the exhaust manifold 12A2 is provided with an exhaust pressure detecting means 22G (for example, a pressure sensor) for detecting the pressure of the exhaust in the exhaust manifold 12A2. The exhaust pressure detecting means 22G outputs a detection signal corresponding to the pressure of the exhaust in the exhaust manifold 12A2 to the control device 70.

The inflow side of the exhaust pipe 12C2 is connected to the outflow side of the turbine 32B of the second supercharger 32, and the outflow side of the exhaust pipe 12C2 is connected in the middle of the exhaust pipe 12C1. The inflow side of the exhaust pipe 12C1 is connected to the outflow side of the turbine 31B of the first supercharger 31, and the outflow side of the exhaust pipe 12C1 is connected to the inflow side of the oxidation catalyst 51. The exhaust pipe 12D, which is downstream from the connection point between the exhaust pipe 12C1 and the exhaust pipe 12C2, is connected to the inflow side of the oxidation catalyst 51. Further, the exhaust pipe 12C1 includes an exhaust pressure detecting means 22B (for example, a pressure sensor) for detecting the exhaust pressure in the exhaust pipe 12C1 and an exhaust temperature detecting means 26 (for example, a temperature sensor) for detecting the temperature of the exhaust in the exhaust pipe 12C1. Etc. are provided. The exhaust pressure detecting means 22B outputs a detection signal corresponding to the detected pressure to the control device 70, and the exhaust temperature detecting means 26 outputs a detection signal corresponding to the detected temperature to the control device 70.

The turbine 31B of the first supercharger 31 is provided with a variable nozzle 31C capable of adjusting the flow velocity of the exhaust gas that rotationally drives the turbine 31B (the opening degree of the flow path that guides the exhaust gas to the turbine 31B can be adjusted). ing. The variable nozzle 31C is operated by a nozzle driving means 31D (for example, an electric motor) that operates in response to a control signal from the control device 70. Further, the nozzle opening degree detecting means 31E (for example, a rotation angle sensor) outputs a detection signal according to the operating state of the nozzle driving means 31D (in this case, the rotation angle of the electric motor) according to the opening degree of the variable nozzle 31C. Output to. The control device 70 controls the nozzle driving means 31D so that the opening degree of the variable nozzle 31C obtained based on the detection signal from the nozzle opening degree detecting means 31E becomes the target nozzle opening degree. The opening degree of the variable nozzle 31C is adjusted from the control device 70 according to the operating state of the internal combustion engine 10. The same applies to the variable nozzle 32C, the nozzle driving means 32D, and the nozzle opening degree detecting means 32E of the turbine 32B of the second supercharger 32, and the description thereof will be omitted.

The outflow side of the oxidation catalyst 51 is connected to the inflow side of the DPF 52 (particulate particulate filter). The oxidation catalyst 51 oxidizes and purifies HC (hydrocarbon) and CO (carbon monoxide) in the exhaust gas of the internal combustion engine 10.

The outflow side of the DPF 52 is connected to the inflow side of the urea SCR53. The DPF 52 collects fine particles in the exhaust. Further, the DPF 52 is provided with a differential pressure detecting means 22C (for example, a differential pressure sensor) for detecting the pressure difference between the inflow side and the outflow side of the DPF 52. The differential pressure detecting means 22C outputs a detection signal corresponding to the pressure difference between the inflow side and the outflow side of the DPF 52 to the control device 70. The control device 70 can estimate the amount of fine particles deposited on the DPF 52 from the differential pressure based on the detection signal from the differential pressure detecting means 22C.

The urea SCR53 uses urea injected from a urea water addition valve (not shown) to reduce and purify NOx (nitrogen oxides) in the exhaust gas.

The vehicle speed detecting means 22H (for example, a vehicle speed sensor) is provided in the vicinity of the wheels of the vehicle, for example, and outputs a detection signal corresponding to the rotation speed of the wheels to the control device 70.

The accelerator pedal depression amount detecting means 27 (for example, an accelerator pedal depression angle sensor) is provided on the accelerator pedal, and outputs a detection signal according to the depression amount of the accelerator pedal by the driver to the control device 70.

The control device 70 has at least a control means 71 (CPU) and a storage means 73. The control device 70 detects the operating state of an internal combustion engine (internal combustion engine system) having a plurality of turbochargers, and controls the amount of fuel injected into the cylinder of the internal combustion engine based on the detected operating state. The control device 70 (control means 71) is not limited to the above-mentioned detection means and each actuator shown in FIG. 1, and operates the internal combustion engine 10 based on detection signals from various detection means including the above-mentioned detection means. Detect the condition. The control device 70 (control means 71) includes various injectors 43A to 43H, an intake bypass valve 61, an intake switching valve 62, an exhaust switching valve 63, nozzle driving means 31D and 32D, and a fuel pressure adjusting pump 41. Control the actuator of. The control device 70 (control means 71) has various processing means such as an accelerator return state calculation means 71A, a target engine braking force related information calculation means 71B, and a deceleration variable nozzle opening degree adjusting means 71C. However, these will be described later. The storage means 73 is, for example, a storage device such as a Flash-ROM, and stores programs, data, and the like for executing a process described later.

The intake bypass valve 61, the intake switching valve 62, and the exhaust switching valve 63 are controlled to be in an open state or a closed state by the control device 70, and a plurality of turbochargers (in this case, 2) are controlled according to the operating state of the internal combustion engine 10. It is a switching means that can switch the number of turbochargers to be operated from among the two turbochargers.

● [Processing procedure of the control device 70 in the first embodiment (FIGS. 2 to 5) and an example of an operation waveform in the first embodiment (FIG. 6)]
Next, an example of the processing procedure of the control device 70 (control means 71) in the first embodiment will be described with reference to the flowcharts shown in FIGS. 2 to 5. The process shown in FIG. 2 is started, for example, at a predetermined time interval (for example, an interval of several [ms] to several tens [ms]), and when activated, the control device 70 (control means 71) proceeds to step S010. To proceed. Note that FIG. 6 shows an example of the operation waveform in the first embodiment.

In step S010, the control device 70 acquires and stores physical quantities based on the detection signals from various detection means as input signal processing, and proceeds to the process in step S015. For example, the current accelerator pedal depression amount, vehicle speed, intake flow rate, atmospheric pressure, intake temperature, supercharging pressure, coolant temperature, amount of fuel to be injected, injection time width, fuel pressure, internal combustion engine rotation speed, exhaust manifold 12A1 Internal exhaust pressure, exhaust manifold 12A2 internal exhaust pressure, turbine downstream exhaust pressure, exhaust temperature, first supercharger / second supercharger operating state, variable nozzle opening of the first supercharger, second supercharger The opening degree of the variable nozzle of the above, the differential pressure of the DPF, etc. are acquired. And the control device 70 is the accelerator pedal depression amount this time, vehicle speed this time, intake flow rate this time, atmospheric pressure this time, intake temperature this time, supercharging pressure this time, coolant temperature this time, fuel amount this time, injection time width this time, fuel pressure this time, This time rotation speed, this time exhaust manifold (12A1) inside exhaust pressure, this time exhaust manifold (12A2) inside exhaust pressure, this time turbine downstream exhaust pressure, this time exhaust temperature, this time supercharger operating state (1 turbo operation or 2 turbo operation), It is stored as the first supercharger nozzle opening this time, the second supercharger nozzle opening this time, the differential pressure this time, and the like. The physical quantities to be stored are not limited to these, and the control device 70 acquires and stores various physical quantities and the like based on the operating state of the internal combustion engine.

In step S015, the control device 70 calculates the accelerator return state and proceeds to step S020. For example, the control device 70 calculates the depression amount reduction rate obtained by subtracting the accelerator pedal depression amount this time from the previous accelerator pedal depression amount (accelerator pedal depression amount at the time of the previous processing) as the accelerator return state. In this case, when calculating the accelerator return state, the control device 70 calculates the accelerator return state based on the depression amount reduction rate, which is the reduction rate of the accelerator pedal depression amount (depression amount reduction rate = previous accelerator pedal depression amount-). This time the accelerator pedal depression amount). Therefore, as shown in FIG. 6, the greater the inclination at which the accelerator pedal depression amount decreases, the greater the depression amount reduction rate.

The control device 70 (control means 71) executing the process of step S015 returns the accelerator pedal at the time of deceleration when the depressed accelerator pedal is returned based on the detection signal from the accelerator pedal depression amount detecting means. It corresponds to the accelerator return state calculation means 71A (see FIG. 1) that calculates the accelerator return state, which is a state.

In step S020, the control device 70 determines whether or not the depression rate reduction rate is equal to or greater than the reduction rate threshold value, and if the depression amount reduction rate is equal to or greater than the reduction rate threshold value (Yes), it is determined that deceleration is in progress. The process proceeds to step S025A, and if the depression rate reduction rate is less than the reduction rate threshold value (No), it is determined that deceleration is not occurring and the process proceeds to step S025B. An appropriate value for the reduction rate threshold value is determined by an experiment or the like.

When the process proceeds to step S025B, the control device 70 determines that the vehicle is not decelerating, sets the engine brake request flag to OFF, and ends the process.

When the process proceeds to step S025A, the control device 70 determines that the vehicle is decelerating, sets the engine brake request flag to ON, and proceeds to the process to step S030. As shown in FIG. 6, the engine brake request flag is set to ON when the depression rate reduction rate is equal to or higher than the reduction rate threshold value. The engine brake request flag is used in [variable nozzle opening degree control] (FIG. 4) and [supercharger switching control] (FIG. 5), which will be described later.

The control device 70 (control means 71) executing the processes of the subsequent steps S030, S035, S040, and S045 is an internal combustion engine based on the accelerator return state during deceleration (when the engine brake request flag = ON). It corresponds to the target engine braking force-related information calculation means 71B (see FIG. 1) that calculates the target engine braking force-related information, which is the target value of the information related to the engine braking force.

In step S030, the control device 70 calculates the target acceleration during deceleration and the target vehicle acceleration during deceleration, and proceeds to step S035. For example, the control device 70 calculates the target acceleration during deceleration using the stepping amount reduction rate, the vehicle speed this time, the stepping amount reduction rate shown in FIG. 7, and the target acceleration characteristic during deceleration. The stepping amount reduction rate and the target acceleration characteristic during deceleration shown in FIG. 7 are stored in the storage means 73, and the stepping amount reduction rate and the target acceleration during deceleration according to the vehicle speed are set.

The target acceleration during deceleration is one of the target engine braking force related information, and is the target value of the acceleration on the deceleration side of the vehicle based on the accelerator release state. As shown in the stepping amount reduction rate / deceleration target acceleration characteristic in FIG. 7, the deceleration target acceleration is set so as to increase as the stepping amount reduction rate increases. The target acceleration during deceleration is set so that the larger the depression rate decrease rate, the larger the increase rate of the target acceleration during deceleration with respect to the increase rate of the depression amount decrease rate (the inclination is not a constant linear shape, and the inclination is It is set to gradually increase). The target acceleration during deceleration is set so as to increase as the vehicle speed increases. Since the air resistance of the vehicle and the friction of the drive system fluctuate according to the vehicle speed, it is more preferable to set the target supercharging pressure during deceleration according to the vehicle speed.

In the example of FIG. 7, an example in which three characteristics of vehicle speed = 0 [km / h], 50 [km / h], and 100 [km / h] are set is shown. For example, the vehicle speed is 75 [km / h]. When [km / h] and stepping amount reduction rate = D1, D1 (50) obtained by using the characteristics of the vehicle speed 50 [km / h] and the stepping amount reduction rate D1 and the vehicle speed 100 [km / h] D1 (100) obtained by using the characteristics and the stepping amount reduction rate D1, and the target acceleration D1 (75) during deceleration corresponding to the stepping amount reduction rate D1 and the vehicle speed 75 [km / h] by using interpolation or the like. Ask for. By appropriately setting the depression reduction rate and target acceleration characteristics during deceleration shown in FIG. 7 through experiments and simulations using an actual vehicle, the engine braking force that can be experienced when decelerating when the accelerator pedal is released can be freely set. Can be set to.

Then, the control device 70 obtains the target vehicle acceleration during deceleration (see FIG. 6) by using the obtained target acceleration during deceleration (see FIG. 7). For example, the control device 70 sets the deceleration target vehicle acceleration that reflects the obtained deceleration target acceleration as the acceleration on the deceleration side. It should be noted that the target acceleration during deceleration may be multiplied by various coefficients to process the target acceleration during deceleration to set the target vehicle acceleration during deceleration. The target vehicle acceleration during deceleration is also one of the target engine braking force related information.

In step S035, the control device 70 calculates a deceleration target torque (see FIG. 6) based on the deceleration target vehicle acceleration, and proceeds to step S040. For example, the control device 70 can calculate the engine torque generated in the current internal combustion engine by using various physical quantities (current rotation speed, current fuel amount, etc.) stored in step S010. Then, the control device 70 can calculate how much the current engine torque should be attenuated in order to satisfy the target vehicle acceleration during deceleration. The target torque during deceleration is also one of the target engine braking force related information.

In step S040, the control device 70 calculates the target exhaust resistance during deceleration (see FIG. 6) based on the target torque during deceleration, and proceeds to step S045. For example, the control device 70 has various physical quantities and the like stored in step S010 (exhaust pressure in the exhaust manifold this time, operating state of the supercharger this time, downstream exhaust pressure of the turbine this time, first supercharger nozzle opening this time, second this time. The exhaust resistance of the current internal combustion engine can be calculated by using the turbocharger nozzle opening, the differential pressure this time, etc.). Then, the control device 70 can calculate how much the current exhaust resistance should be increased in order to satisfy the target torque during deceleration. By increasing the exhaust resistance, the pump loss torque of the piston of the internal combustion engine can be increased, so that the engine torque generated by the internal combustion engine can be reduced. Further, the control device 70 can calculate the pump loss torque by using various physical quantities (physical quantities based on the operating state of the internal combustion engine) acquired in step S010. The target exhaust resistance during deceleration is also one of the target engine braking force related information.

In step S045, the control device 70 calculates the pressure inside the deceleration target exhaust manifold (see FIG. 6) based on the deceleration target exhaust resistance, and proceeds to step S050. For example, the control device 70 can calculate (detect) the pressure inside the exhaust manifold of the current internal combustion engine by using various physical quantities and the like (exhaust pressure inside the exhaust manifold this time) stored in step S010. Then, the control device 70 can calculate how much the current pressure inside the exhaust manifold should be increased in order to satisfy the target exhaust resistance during deceleration. The pressure inside the target exhaust manifold during deceleration is also one of the information related to the target engine braking force.

In step S050, the control device 70 executes [SB100: variable nozzle adjustment process during deceleration] shown in FIG. 3 to end the process. In the first embodiment, [SB100: variable nozzle adjustment processing during deceleration] (see FIG. 3) is executed in step S050, but in the second embodiment described later, [SB200: variable during deceleration] is executed. Nozzle adjustment process] (see FIG. 9) is executed.

The control device 70 (control means 71) executing the process of step S050 opens the variable nozzle at the time of deceleration based on the target engine braking force related information (in this case, the pressure in the target exhaust manifold during deceleration). It corresponds to the variable nozzle opening adjustment means 71C (see FIG. 1) during deceleration, which adjusts the engine braking force of the internal combustion engine by adjusting to the closed side and increasing the exhaust pressure in the exhaust manifold. The details of [SB100: variable nozzle adjustment processing during deceleration] will be described below with reference to FIG.

● [SB100: Variable nozzle adjustment processing during deceleration] (Fig. 3)
When the control device 70 starts [SB100: variable nozzle adjustment process during deceleration] in step S050 shown in FIG. 2, the process proceeds to step SB110 shown in FIG.

In step SB110, the control device 70 determines whether or not only the first turbocharger is operating in the current turbocharger operating state (1 turbo operation or 2 turbo operation) stored in step S010. When only the first turbocharger is operating (1 turbo is operating) (Yes), the process proceeds to step SB115, and the first supercharger and the second turbocharger are operating (2 turbo is operating). If there is (No), the process proceeds to step SB140B.

When the process proceeds to step SB115, the control device 70 calculates the upper limit rotation speed of the first turbocharger and proceeds to the process to step SB120. For example, the control device 70 includes various physical quantities (current supercharging pressure, this time atmospheric pressure, this time intake flow rate, etc.) stored in step S010, and intake flow rate / supercharging pressure / atmospheric pressure / upper limit rotation speed characteristics (FIG. 8). The upper limit rotation speed of the first turbocharger is calculated based on (see). The control device 70 uses the intake air flow rate and the supercharging pressure / atmospheric pressure to extract the upper limit rotation speed line (with a single point chain line in FIG. 8) from the intake air flow rate / supercharging pressure / atmospheric pressure / upper limit rotation speed characteristics. Therefore, the upper limit rotation speed of the first supercharger can be calculated. The intake flow rate, supercharging pressure / atmospheric pressure, and upper limit rotation speed characteristic shown in FIG. 8 are stored in the storage means 73. The method for calculating the upper limit rotation speed of the first turbocharger is not limited to this method.

In step SB120, the control device 70 estimates or detects the rotation speed of the first supercharger and proceeds to step SB125. For example, when the control device 70 has the turbine rotation speed detecting means of the first supercharger, the control device 70 detects the rotation speed of the first supercharger based on the detection signal from the turbine rotation speed detecting means. When the turbine rotation speed detecting means is not provided, various physical quantities stored in step S010 (current rotation speed, exhaust pressure in the exhaust manifold this time, exhaust pressure downstream of the turbine this time, exhaust temperature this time, first excess this time). The rotation speed of the first turbocharger is estimated using the feeder nozzle opening degree, etc.).

In step SB125, the control device 70 determines whether or not the detected or estimated rotation speed of the first supercharger is less than the upper limit rotation speed of the first supercharger, and the rotation speed is less than the upper limit rotation speed of the first supercharger. If there is (Yes), the process proceeds to step SB140A, and if it is equal to or higher than the upper limit rotation speed of the first turbocharger (No), the process proceeds to step SB130.

When the process proceeds to step SB140A, the control device 70 opens the first variable nozzle so that the exhaust pressure in the exhaust manifolds 12A1 and 12A2 becomes the target exhaust manifold internal pressure during deceleration calculated in step S045. (To the closing side) feedback control (controlling the nozzle driving means 31D) is performed to end the process shown in FIG. 3, and the process returns to the downstream of step S050 shown in FIG. 2 to end the process.

When the process proceeds to step SB130, the switching means is controlled to operate the first supercharger and the second supercharger. For example, the control device 70 controls the intake switching valve 62 (switching means) shown in FIG. 1 from the closed state to the open state, keeps the intake bypass valve 61 (switching means) in the closed state, and exhaust switching valve 63 (switching means). ) Is controlled from the closed state to the open state, from the 1-turbo state in which only the first supercharger is operated to the 2-turbo state in which the first supercharger and the second supercharger are operated. Change the operating state of. By operating the first supercharger and the second supercharger to divide the exhaust energy even if the upper limit rotation speed of the first supercharger is exceeded in the operating state of only the first supercharger. , Both superchargers can be prevented from reaching the upper limit rotation speed. In the description of the present embodiment, an example in which the intake bypass valve 61, the intake switching valve 62, and the exhaust switching valve 63 are provided as the switching means has been described, but the switching means switches the number of superchargers to be operated. Anything that can be done is sufficient.

When the process proceeds to step SB140B, the control device 70 closes (closes) the opening degree of the first variable nozzle so that the exhaust pressure in the exhaust manifold 12A1 becomes the deceleration target exhaust manifold internal pressure calculated in step S045. Feedback control (controlling the nozzle driving means 31D) is performed (on the side). Further, the control device 70 feedback-controls (nozzle drive) the opening degree of the second variable nozzle (to the closing side) so that the exhaust pressure in the exhaust manifold 12A2 becomes the target exhaust manifold internal pressure during deceleration calculated in step S045. Means 32D is controlled). Then, the control device 70 ends the process shown in FIG. 3, returns to the downstream of step S050 shown in FIG. 2, and ends the process.

In this way, when adjusting the opening degree of the variable nozzle (in the processing of SB100), the control device 70 operates only the number of revolutions of the supercharger that is operating (in this case, only the first supercharger). When the number of revolutions of the first turbocharger (in this case, the upper limit of the number of revolutions of the first turbocharger) exceeds the upper limit (in this case, the intake bypass valve, the intake switching valve, the exhaust switching valve). ) To increase the number of turbochargers to be operated (in this case, increase to the first turbocharger + the second turbocharger). Then, the control device 70 has a variable nozzle of each of the operated superchargers (in this case, the first supercharger and the second supercharger) (in this case, the variable nozzle of the first supercharger and the second supercharger). 2 Adjust the variable nozzle of the turbocharger) to the closing side to increase the pressure inside the exhaust manifold.

In the operation waveform shown in FIG. 6, the operating state of the turbocharger is changed from "first supercharger only" to "first supercharger + second" before the rotation speed of the first supercharger reaches the upper limit rotation speed. An example of the state of switching to the "supercharger" is shown. As shown in FIG. 6, by switching from the operating state of "only the first supercharger" to the operating state of "first supercharger + second supercharger", the exhaust energy is changed to the first supercharger and the first supercharger. Since the number of revolutions of the first supercharger can be reduced by dividing the turbocharger into two turbochargers, it is possible to appropriately prevent the reliability of the supercharger from being affected.

● [Existing variable nozzle opening control (Fig. 4) and existing turbocharger switching control (Fig. 5)]
Next, changes to the existing variable nozzle opening control will be described with reference to FIG. When the processing of steps SB140A and SB140B (see FIG. 3) described above is executed, the existing variable nozzle opening degree control is not executed.

Therefore, as shown in FIG. 4, the control device 70 first determines in step SN010 whether or not the engine brake request flag (see FIG. 2) is ON in the existing variable nozzle opening control process. To do. Then, when the engine brake request flag is ON (Yes), the control device 70 skips the existing variable nozzle opening control of step SN100, and when the engine brake request flag is OFF (No), the existing variable nozzle opening control of step SN100 is skipped. The variable nozzle opening control of is executed.

Next, changes to the existing supercharger switching control (control of the intake bypass valve, the intake switching valve, and the exhaust switching valve) will be described with reference to FIG. When executing the process of step SB130 (see FIG. 3) described above, the existing supercharger switching control is not executed.

Therefore, as shown in FIG. 5, the control device 70 first determines in step ST010 whether or not the engine brake request flag (see FIG. 2) is ON in the process of the existing supercharger switching control. To do. When the engine brake request flag is ON (Yes), the control device 70 skips the existing supercharger switching control in step ST100, and when the engine brake request flag is OFF (No), the existing supercharger switching control in step ST100 is skipped. The supercharger switching control of is executed.

[[Processing procedure of the control device 70 in the second embodiment (FIG. 9) and an example of an operation waveform in the second embodiment (FIG. 10)]
Next, the second embodiment will be described with reference to the flowchart shown in FIG. 9 and the operation waveform shown in FIG. In the second embodiment, in step S050 shown in FIG. 2, [SB200: variable nozzle adjustment process during deceleration] (FIG. 9) is executed instead of [SB100: variable nozzle adjustment process during deceleration] (FIG. 3). The difference is that they do the same. Hereinafter, [SB200: variable nozzle adjustment processing during deceleration] shown in FIG. 9 will be described. In the flowchart shown in FIG. 9, steps SB215, SB220, and SB225 are changed with respect to the flowchart shown in FIG. 3, and the rotation speed of the first supercharger is changed to the exhaust flow rate to the first supercharger. ing. Therefore, in the operation waveform of FIG. 10, the first supercharger rotation speed and the second supercharger rotation speed in the operation waveform of FIG. 6 are the exhaust flow rate to the first supercharger and the exhaust gas to the second supercharger. It has been changed to the flow rate.

When the control device 70 starts [SB200: variable nozzle adjustment process during deceleration] in step S050 shown in FIG. 2, the process proceeds to step SB210 shown in FIG.

In step SB210, the control device 70 determines whether or not only the first turbocharger is operating in the current turbocharger operating state (1 turbo operation or 2 turbo operation) stored in step S010. When only the first turbocharger is operating (1 turbo is operating) (Yes), the process proceeds to step SB215, and the first turbocharger and the second turbocharger are operating (2 turbo is operating). If there is (No), the process proceeds to step SB240B.

When the process proceeds to step SB215, the control device 70 calculates the upper limit exhaust flow rate of the first supercharger and proceeds to the process to step SB220. For example, the control device 70 is based on various physical quantities stored in step S010 (current rotation speed, current exhaust pressure in the exhaust manifold, this time first supercharger nozzle opening, this time turbine downstream exhaust pressure, etc.). 1 Calculate the upper limit exhaust flow rate of the turbocharger. There are various methods for calculating the upper limit exhaust flow rate of the first turbocharger, but since it is an existing method, the details will be omitted.

In step SB220, the control device 70 estimates the exhaust gas flow rate to the first supercharger and proceeds to step SB225. For example, the control device 70 stores various physical quantities and the like (current rotation speed, this time exhaust pressure in the exhaust manifold, this time the first supercharger nozzle opening, this time turbine downstream exhaust pressure, this time exhaust temperature, etc.) stored in step S010. It is used to estimate the exhaust flow rate to the first turbocharger.

In step SB225, the control device 70 determines whether or not the estimated exhaust flow rate to the first supercharger is less than the upper limit exhaust flow rate of the first supercharger, and is less than the upper limit exhaust flow rate of the first supercharger. If (Yes), the process proceeds to step SB240A, and if it is equal to or higher than the upper limit exhaust flow rate of the first turbocharger (No), the process proceeds to step SB230.

When the process proceeds to step SB240A, the control device 70 opens the first variable nozzle so that the exhaust pressure in the exhaust manifolds 12A1 and 12A2 becomes the target exhaust manifold internal pressure during deceleration calculated in step S045. (To the closing side) feedback control (controlling the nozzle driving means 31D) is performed to end the process shown in FIG. 3, and the process returns to the downstream of step S050 shown in FIG. 2 to end the process.

When the process proceeds to step SB230, the switching means is controlled to operate the first supercharger and the second supercharger. For example, the control device 70 controls the intake switching valve 62 (switching means) shown in FIG. 1 from the closed state to the open state, keeps the intake bypass valve 61 (switching means) in the closed state, and exhaust switching valve 63 (switching means). ) Is controlled from the closed state to the open state, from the 1 turbo state in which only the first supercharger is operated to the 2 turbo state in which the first supercharger and the second supercharger are operated. Change the operating state (number of turbochargers to operate). By operating the first supercharger and the second supercharger to divide the exhaust energy even if the upper limit exhaust flow rate of the first supercharger is exceeded in the operating state of only the first supercharger. , Both turbochargers can be prevented from reaching the upper limit exhaust flow rate. In the description of the present embodiment, an example in which the intake bypass valve 61, the intake switching valve 62, and the exhaust switching valve 63 are provided as the switching means has been described, but the switching means switches the number of superchargers to be operated. Anything that can be done is sufficient.

When the process proceeds to step SB240B, the control device 70 closes (closes) the opening degree of the first variable nozzle so that the exhaust pressure in the exhaust manifold 12A1 becomes the target exhaust manifold internal pressure during deceleration calculated in step S045. Feedback control (controlling the nozzle driving means 31D) is performed (on the side). Further, the control device 70 feedback-controls (nozzle drive) the opening degree of the second variable nozzle (to the closing side) so that the exhaust pressure in the exhaust manifold 12A2 becomes the target exhaust manifold internal pressure during deceleration calculated in step S045. Means 32D is controlled). Then, the control device 70 ends the process shown in FIG. 9, returns to the downstream of step S050 shown in FIG. 2, and ends the process.

In this way, when adjusting the opening degree of the variable nozzle (in the processing of SB200), the control device 70 operates only the exhaust flow rate to the operating supercharger (in this case, only the first supercharger). When the exhaust flow rate to the first turbocharger (in this case, the upper limit exhaust flow rate of the first supercharger) exceeds the upper limit exhaust flow rate (in this case, the intake bypass valve, the intake switching valve, the exhaust). Increase the number of turbochargers that should be operated by controlling the switching valve) (in this case, increase to the first turbocharger + the second turbocharger). Then, the control device 70 is a variable nozzle (in this case, a variable nozzle of the first supercharger and a second supercharger) of each of the operated superchargers (in this case, the first supercharger and the second supercharger). Adjust the variable nozzles of the turbocharger) to the closing side to increase the pressure inside the exhaust manifold.

In the operation waveform shown in FIG. 10, the operating state of the turbocharger is changed from "only the first turbocharger" to "first supercharger + first" before the exhaust flow rate to the first supercharger reaches the upper limit exhaust flow rate. An example of the state of switching to "2 supercharger" is shown. As shown in FIG. 6, by switching from the operating state of "only the first supercharger" to the operating state of "first supercharger + second supercharger", the exhaust gas is changed to the first supercharger and the first supercharger. Since it is possible to reduce the exhaust flow rate to the first supercharger by dividing it into two superchargers, it is possible to appropriately prevent the reliability of the supercharger from being affected.

The control device for an internal combustion engine of the present invention is not limited to the configuration, structure, processing procedure, operation, etc. described in the present embodiment, and various changes, additions, and deletions can be made without changing the gist of the present invention. is there. Further, the internal combustion engine system is not limited to the one shown in the example of FIG. 1, and can be applied to various internal combustion engine systems.

In the description of the present embodiment, an internal combustion engine system having two superchargers, a first supercharger and a second supercharger, has been described as an example, but an internal combustion engine having one supercharger is also described. It is applicable and is also applicable to an internal combustion engine having three or more turbochargers. Further, in the description of the present embodiment, an example of a configuration in which the first supercharger and the second supercharger are supercharged in parallel (a configuration in which supercharging can be performed in series) has been described. It is possible to apply the present invention regardless of whether the turbocharger is supercharged in parallel or supercharged in series.

In the description of the present embodiment, the target engine braking force related information includes the target acceleration during deceleration, the target vehicle acceleration during deceleration, the target torque during deceleration, the target exhaust resistance during deceleration, and the pressure inside the target exhaust manifold during deceleration. Explained, and explained that the control device adjusts the opening degree of the variable nozzle so that the exhaust pressure in the exhaust manifold becomes the target exhaust manifold internal pressure at the time of deceleration. However, for example, the opening degree of the variable nozzle may be adjusted so that the acceleration of the vehicle becomes the target vehicle acceleration during deceleration, and the opening degree of the variable nozzle may be adjusted so that the corresponding physical quantity becomes the target engine braking force related information. Just do it. Further, the stepping amount reduction rate and the target acceleration characteristic during deceleration shown in FIG. 7 do not have to be a curved characteristic but may be a linear characteristic, and are set so as to increase as the vehicle speed increases. It does not have to be.

Further, the numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values. Further, the above (≧), the following (≦), the larger (>), the less than (<), etc. may or may not include the equal sign.

1 Internal combustion engine system 10 Internal combustion engine 11A, 11B1, 11B2, 11C1, 11C2, 11D Intake pipe 11CB Intake bypass pipe 11E Intake manifold 12A1, 12A2 Exhaust manifold 12B1, 12B2, 12C1, 12C2 Exhaust pipe 12BB Exhaust bypass pipe 21 22A Supercharging pressure detecting means 22B Exhaust pressure detecting means 22C Differential pressure detecting means 22D Atmospheric pressure detecting means 22E Intake temperature detecting means 22F, 22G Exhaust pressure detecting means 22H Vehicle speed detecting means 24 Coolant temperature detecting means 25 Rotation detecting means 26 Exhaust temperature Detection means 27 Accelerator pedal depression amount detection means 31 First supercharger 31A, 32A Compressor 31B, 32B Turbine 31C, 32C Variable nozzle 31D, 32D Nozzle drive means 31E, 32E Nozzle opening detection means 32 Second supercharger 41 Fuel pressure Adjustment pump 51 Oxidation catalyst 52 DPF
53 Urea SCR
61 Intake bypass valve (switching means)
62 Intake switching valve (switching means)
63 Exhaust switching valve (switching means)
70 Control device 71 Control means 71A Accelerator return state calculation means 71B Target engine braking force related information calculation means 71C Variable nozzle opening adjustment means during deceleration 73 Storage means

Claims (6)

A turbocharger with a variable nozzle whose opening is adjusted according to the operating condition of the internal combustion engine,
Accelerator pedal depression amount detecting means for detecting accelerator pedal depression amount,
The operating state of the internal combustion engine including the accelerator pedal depression amount is detected for the internal combustion engine system mounted on the vehicle, and the actuator including the variable nozzle is controlled based on the detected operating state. It is a control device for an internal combustion engine.
The turbocharger has a turbine that rotates using the energy of exhaust gas.
The variable nozzle can adjust the opening degree of the flow path that guides the exhaust gas to the turbine according to the operating state of the internal combustion engine.
The control device is
Based on the detection signal from the accelerator pedal depression amount detecting means, the accelerator return state calculating means which calculates the accelerator return state which is the return state of the accelerator pedal at the time of deceleration when the depressed accelerator pedal is returned, and the accelerator return state calculation means.
At the time of deceleration, a target engine braking force-related information calculating means for calculating target engine braking force-related information, which is a target value of information related to the engine braking force of the internal combustion engine based on the accelerator release state, and
At the time of deceleration, the engine braking force of the internal combustion engine is adjusted by adjusting the opening degree of the variable nozzle to the closing side and increasing the exhaust pressure in the exhaust manifold based on the target engine braking force related information. , Variable nozzle opening adjustment means during deceleration,
Have,
Control device for internal combustion engine. The control device for an internal combustion engine according to claim 1.
The control device is
When calculating the accelerator return state by the accelerator return state calculating means, the accelerator return state is calculated based on the depression amount reduction rate, which is the reduction rate of the accelerator pedal depression amount.
Control device for internal combustion engine. The control device for an internal combustion engine according to claim 2.
The control device is
The target engine braking force-related information calculated by the target engine braking force-related information calculation means includes a deceleration target acceleration which is a target value of the acceleration on the deceleration side of the vehicle based on the accelerator release state. And
The target acceleration during deceleration is
It is set so that the larger the stepping amount reduction rate is, the larger the stepping amount reduction rate is, and the larger the stepping amount reduction rate is, the larger the increase rate of the target acceleration during deceleration is set with respect to the increase rate of the stepping amount reduction rate. ing,
Control device for internal combustion engine. The control device for an internal combustion engine according to claim 3.
The target acceleration during deceleration is
Further, it is set so that the vehicle speed, which is the speed of the vehicle, increases as the vehicle speed increases.
Control device for internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 4.
The internal combustion engine system includes
Multiple turbochargers are installed,
A switching means capable of switching the number of the superchargers to be operated from among the plurality of the superchargers according to the operating state of the internal combustion engine is provided.
The control device is
Based on the operating state of the internal combustion engine, it is possible to calculate the exhaust flow rate, which is the flow rate of the exhaust gas from the internal combustion engine, and the upper limit exhaust flow rate to each of the superchargers.
When adjusting the opening degree of the variable nozzle by the deceleration variable nozzle opening degree adjusting means, if the exhaust flow rate to the supercharger being operated exceeds the upper limit exhaust flow rate, the switching means is controlled. The number of the superchargers to be operated is increased, and the opening degree of the variable nozzle of each of the superchargers operated is adjusted to the closing side.
Control device for internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 4.
The internal combustion engine system includes
Multiple turbochargers are installed,
A switching means capable of switching the number of the superchargers to be operated from among the plurality of the superchargers according to the operating state of the internal combustion engine is provided.
The control device is
It is possible to calculate the upper limit rotation speed of each supercharger based on the operating state of the internal combustion engine.
When adjusting the opening degree of the variable nozzle by the deceleration variable nozzle opening degree adjusting means, when the rotation speed of the supercharger being operated exceeds the upper limit rotation speed, the switching means is controlled and operated. The number of the superchargers to be operated is increased, and the opening degree of the variable nozzle of each of the superchargers operated is adjusted to the closing side.
Control device for internal combustion engine.

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