JP3807473B2 - Internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine (hereinafter referred to as an engine) capable of switching between uniform combustion and stratified combustion.
[0002]
[Related background]
In recent years, in order to reduce emissions and improve fuel efficiency, an engine that enables stratified combustion with a lean air-fuel ratio as a whole has been put into practical use after an air-fuel mixture near the stoichiometric air-fuel ratio is formed around the spark plug. ing. As one of the techniques for realizing stratified combustion, for example, JP-A-9-79079 proposes an in-cylinder injection engine that directly injects fuel into a cylinder. In this in-cylinder injection engine, fuel is injected in the compression stroke and transferred to the spark plug together with the reverse tumble flow generated in the cavity of the piston, so that the mixture near the stoichiometric air-fuel ratio that can be ignited around the spark plug. In addition, it is possible to operate at an extremely lean air-fuel ratio of about 40 air-fuel ratio.
[0003]
The above-described compression stroke injection is mainly performed during idle operation or low load traveling, and fuel is injected during the intake stroke during high load traveling. In this intake stroke injection, as in a normal intake pipe injection type engine, a uniform air-fuel mixture is formed in the cylinder and uniform combustion is performed, so that a large amount of fuel is burned to ensure engine output.
[0004]
[Problems to be solved by the invention]
Specifically, the switching between the uniform combustion and the stratified combustion is performed according to a map set in a region based on the target average effective pressure Pe (representing the load) and the engine rotational speed Ne shown in FIG. Therefore, it is desirable to perform stratified combustion advantageous in terms of fuel efficiency, and there is a desire to expand the stratified combustion region. However, if the stratified combustion region is excessively expanded to the high load side, the fuel injection amount increases with the target average effective pressure Pe, so that the air-fuel ratio around the spark plug becomes overrich, and incomplete combustion is caused. It is generated and smoke is generated. Therefore, for example, even during slow acceleration, when the predetermined load is exceeded, there is no choice but to switch to uniform combustion from the viewpoint of exhaust gas, leaving room for improvement in terms of improving fuel consumption.
[0005]
An object of the present invention is to provide an internal combustion engine capable of achieving further improvement in fuel consumption by expanding the operation range in which stratified combustion is possible to the high load side while preventing the generation of smoke.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a supercharging means for supercharging intake air of an internal combustion engine, and a first operation for performing stratified combustion is set so as to include a supercharging region by the supercharging means. An operation state switching means for switching the operation state of the internal combustion engine, a supercharging pressure adjustment means capable of adjusting a supercharging pressure of the supercharging means, and an operation state switching When the switch is made between the first operating state and the second operating state by the means, the supercharging pressure adjusting means is controlled so that the second operating state side has a low supercharging pressure with respect to the first operating state. When the desired supercharging pressure is not reached in the supercharging region by the supercharging means in the first operating state, the supercharging pressure is reduced by the supercharging pressure adjusting means, and the operating state switching means a fail-safe control means for switching a specific area of the first operating state to the second operating state by It includes those were.
Stratified combustion is realized by forming an air / fuel mixture with an appropriate air / fuel ratio around the spark plug, but it cannot be performed at a predetermined load or higher because it becomes overrich as the fuel injection amount increases. It must be switched to. Here, when supercharging is performed, an amount of oxygen sufficient to meet the increase in fuel injection amount is ensured. Therefore, an air-fuel mixture having an appropriate air-fuel ratio is formed around the spark plug, and smoke due to incomplete combustion is formed. It becomes possible to perform stratified combustion without generating. Therefore, the area | region of a 1st driving | running state is expanded to the high load side, and the opportunity to perform stratified combustion increases. In the second operating state, the engine torque becomes higher in the second operating state than in the first operating state, but the supercharging pressure is reduced accordingly. Switchable.
Also, in the supercharging region in the first operating state, that is, the region where stratified combustion is realized by supercharging, when the desired supercharging pressure is insufficient for some reason, it is suitable for uniform combustion in the second operating state. Thus, after the supercharging pressure is reduced, the operation state is switched to the second operation state, and as a result, the injected fuel is reliably ignited and burned without deteriorating the exhaust gas characteristics.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
[First embodiment]
Hereinafter, a first embodiment in which the present invention is embodied in an in-cylinder injection engine that directly injects fuel into a cylinder will be described.
In the overall configuration diagram of FIG. 1, reference numeral 1 denotes an in-cylinder injection gasoline engine for an automobile, and the combustion chamber 5 and the intake system are designed exclusively for in-cylinder injection. The cylinder head 2 of the engine 1 is provided with an electromagnetic fuel injection valve 4 together with a spark plug 3 for each cylinder, and high-pressure fuel supplied from a fuel pump (not shown) is supplied from the fuel injection valve 4 to the combustion chamber 5. It is designed to be injected directly into the inside. An intake port 6 is formed in the cylinder head 2 in a substantially upright direction, and an intake passage 7 is connected to the intake port 6. The intake air taken in from the intake passage 7 is introduced into the combustion chamber 5 through the intake port 6 as the intake valve 8 is opened, and generates a reverse tumble flow in the cavity of the piston 5a. Fuel is injected from the injection valve 4 and burned by ignition of the spark plug 3.
[0011]
The intake passage 7 includes an air flow sensor (AFS) 9 that detects the intake air amount Af, a compressor 11 of a turbocharger 10 that supercharges the intake air, an intercooler 12 that cools the intake air whose temperature has increased due to the supercharging by the compressor 11, A throttle valve 14 that is opened and closed by a step motor 13 to adjust the amount of intake air is provided. An exhaust port 15 is formed in the cylinder head 2 in a substantially horizontal direction, and an exhaust passage 16 is connected to the exhaust port 15. The exhaust gas after combustion is discharged into the atmosphere through the exhaust port 15 and the exhaust passage 16 when the exhaust valve 17 is opened. The exhaust passage 16 is provided with a turbine 18 of the turbocharger 10 that is coaxially coupled to the compressor 11 and driven to rotate by exhaust gas, and a catalyst and a silencer (not shown).
[0012]
The turbocharger 10 is configured as a variable geometry turbo capable of arbitrarily adjusting the supercharging pressure, and a plurality of vanes 19 are disposed in the turbine 18 so as to surround the turbine rotor 18a. The opening degree of these vanes 19 is simultaneously changed by the vane adjusting actuator 21 via the rods 20 (illustration of the connection state between the vanes 19 and the rods 20), and as a result, the flow velocity of the exhaust gas introduced into the turbine rotor 18a. Changes and the supercharging pressure is adjusted.
[0013]
In the vehicle compartment, an input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) used for storing control programs and control maps, an ECU (engine) equipped with a central processing unit (CPU), a timer counter, etc. A control unit 31 is installed and performs overall control of the engine 1. On the input side of the ECU 31, in addition to the air flow sensor 9, an accelerator sensor 32 that detects an accelerator operation amount APS by a driver, a crank angle sensor 33 that outputs a crank angle signal for each predetermined crank angle, and a turbocharger 10. A supercharging pressure sensor 34 for detecting the supercharging pressure Pb is connected. Further, the ignition plug 3 and the fuel injection valve 4 are connected to the output side of the ECU 31, and an ETV-CU (electronic throttle valve control unit) 35 is connected to the ETV-CU 35. A step motor 13 of the valve 14 is connected.
[0014]
Based on detection information from each sensor, the ECU 31 performs fuel injection control by the fuel injection valve 4, ignition timing control by the ignition plug, vane opening control of the turbocharger 10, throttle opening control via the ETV-CU 35, and the like. Execute.
Next, the control executed by the ECU 31 in the in-cylinder injection engine 1 configured as described above will be described. Prior to that, the characteristics of the map used for determining the fuel injection mode in the fuel injection control will be described in detail. .
[0015]
FIG. 2 is an explanatory diagram showing a control map for determining the fuel injection mode, and this map is stored in the storage device of the ECU 31. In the fuel injection control, the fuel injection mode is switched based on the target average effective pressure Pe (representing the load) of the engine 1 and the engine speed Ne according to this map. The fuel injection mode representing the stroke in which the fuel is injected is roughly divided into a compression stroke injection mode and an intake stroke injection mode. As shown by the solid line in the figure, the compression stroke injection mode has a target average effective pressure Pe and an engine speed. Ne is set in a relatively low region, and the intake stroke injection mode is set in a region higher than Ne.
[0016]
In the compression stroke injection mode, fuel is injected in the compression stroke and transferred to the spark plug 3 together with the reverse tumble flow generated in the cavity of the piston 5a, so that the mixture near the stoichiometric air-fuel ratio that can be ignited around the spark plug 3 is obtained. After forming the air, it is possible to perform stratified combustion at an ultra-lean air-fuel ratio of about 40 air-fuel ratio as a whole, achieving reduction of CO and HC and improvement of fuel consumption. Also, in the intake stroke injection mode, fuel is injected in the intake stroke as in a normal intake pipe injection type engine, and a uniform mixture is formed in the cylinder to perform uniform combustion, thereby burning a large amount of fuel. To ensure engine output. Although not shown, the intake stroke injection mode is subdivided into an SF / B mode that performs feedback control to the theoretical air-fuel ratio and an O / L mode that performs open-loop control to the rich air-fuel ratio. Within the injection mode region, the SF / B mode is set to a region where the target average effective pressure Pe and the engine rotational speed Ne are relatively low, and the O / L mode is set to a relatively high region.
[0017]
In this embodiment, the map characteristic of FIG. 2 is set on the assumption that the turbocharger 10 is supercharged. That is, as shown by the solid line, the intake air is supercharged by the turbocharger 10 so that the volumetric efficiency (unit intake air) is higher than that of a naturally aspirated in-cylinder injection engine (hereinafter referred to as an NA engine) indicated by a two-dot chain line. The index representing the amount of oxygen that contributes to combustion per stroke) has increased significantly. This is an advantage of the known turbocharger 10 that increases the amount of combustible fuel and improves the full-open torque. However, in the engine 1 of this embodiment that performs stratified combustion, the stratified combustion region (compression stroke injection mode) 2) can be expanded to the high load side (B region in FIG. 2) on which the turbocharger 10 is supercharged.
[0018]
As described in detail below, as described in the problem to be solved by the invention, the limit of the stratified combustion region related to the load is that when the fuel injection amount increases with the target average effective pressure Pe, The region of the stratified combustion is set with a target average effective pressure Pe that is determined based on whether the air-fuel ratio becomes over-rich and does not generate smoke due to the over-rich. By supercharging the turbocharger 10, an oxygen amount sufficient to meet the increase in the fuel injection amount is ensured, so that an air-fuel mixture with an appropriate air-fuel ratio is formed around the spark plug 3 even on the higher load side, Layered combustion is possible without generating smoke due to incomplete combustion. Therefore, in the engine 1 of the present embodiment, the region of the compression stroke injection mode is greatly expanded to the high load side (high Pe side) compared to the NA engine. The reason why the compression stroke injection mode region is not expanded in the low rotation region is that sufficient exhaust pressure for operating the turbocharger 10 cannot be obtained in this region, and the supercharging pressure does not increase.
[0019]
On the other hand, the ECU 31 executes the main routine shown in FIG. 3 at a predetermined control interval. First, detection information from each sensor is input in step S2, and based on the accelerator operation amount APS detected by the accelerator sensor 32 in step S4 and the engine rotational speed Ne calculated from the crank angle signal from the crank angle sensor 33. Then, the target average effective pressure Pe is calculated according to a preset map. Next, in step S6, the fuel injection mode is determined from the map of FIG. 2 based on the target average effective pressure Pe, and in order to achieve the target average effective pressure Pe on the basis of the fuel injection mode, the fuel injection amount, the fuel injection timing, The ignition timing, the target supercharging pressure of the turbocharger 10, the target throttle opening, etc. are set. Although not described in detail, these setting processes are performed according to a map (not shown).
[0020]
Thereafter, the corresponding control is executed in step S10 based on each set control amount, and this routine is terminated. For example, the fuel injection valve 4 is driven and controlled based on the fuel injection amount and the fuel injection timing, the fuel injection is executed in the stroke determined in the fuel injection mode, and the ignition plug 3 is driven and controlled based on the ignition timing. To do. Further, the vane adjustment actuator 21 is driven and controlled based on the target boost pressure, the vane opening of the turbocharger 10 is adjusted, the target throttle opening is output to the ETV-CU 35, and the throttle opening θTH is adjusted. . In the present embodiment, the ECU 31 when executing the process of step S6 described above functions as an operating state switching unit, and the turbocharger 10 functions as a supercharging unit.
[0021]
Since the turbocharger 10 is supercharged as described above, the compression stroke injection mode can be continued without generating smoke up to a region where the target average effective pressure Pe is higher than that of the N / A engine. Opportunities for super lean stratified combustion in stroke injection mode are dramatically increased. Therefore, it is possible to further improve fuel efficiency by fully utilizing the advantages of the compression stroke injection mode while preventing the occurrence of smoke.
[0022]
[Second Embodiment]
Hereinafter, a second embodiment in which the present invention is embodied in another in-cylinder injection engine 1 will be described. The basic configuration of the engine 1 of the present embodiment, the control contents based on the main routine of FIG. 3, the map characteristics of FIG. 2, and the like are the same as those of the first embodiment. The vane opening degree of the charger 10 is controlled. Therefore, the difference will be described mainly.
[0023]
The ECU 31 executes the transient control routine shown in FIG. 4 at a predetermined control interval. First, in step S12, it is determined whether or not the fuel injection mode has been switched from the compression stroke injection mode to the intake stroke injection mode as a result of the control by the main routine described above. If NO (No), the process proceeds to step S14. Conversely, it is determined whether or not the intake stroke injection mode has been switched to the compression stroke injection mode. If NO, the routine is terminated as it is. Therefore, in step S10 of the main routine in this case, the vane opening degree of the turbocharger 10 is controlled so as to achieve the target boost pressure set in step S8 as usual.
[0024]
On the other hand, when the determination in step S12 is YES (positive), the vane opening is corrected to the open side in step S16, and when the determination in step S14 is YES, the vane opening is closed in step S18. After correction, the routine is terminated. The vane opening correction amount is determined in advance by an bench test of the engine 1, and the correction amount is read from the map according to, for example, the engine rotational speed Ne, the target average effective pressure Pe, and the like. In the present embodiment, the ECU 31 when executing the processes of steps S12 to S18 described above functions as a transient control unit, and the vane 19 and the vane adjusting actuator 21 function as a supercharging pressure adjusting unit.
[0025]
Based on the correction processing in step S16 and step S18, each control amount is set on the premise of the corrected vane opening degree in step S8 of the main routine. The injection amount is set to decrease, and conversely, at the time of correction to the closing side, the fuel injection amount is set to increase according to the increase in the supercharging pressure. Therefore, by the process of step S10, control is performed in a direction in which the engine torque is temporarily reduced at the time of correction to the open side, and control is performed in a direction to temporarily increase the engine torque at the time of correction in the close side.
[0026]
Here, compared with the compression stroke injection mode of stratified combustion, in the intake stroke injection mode of uniform combustion, the engine torque generated due to the difference in the combustion mode and the control contents such as the throttle opening and ignition timing in accordance therewith. Is slightly higher. Therefore, switching from the compression stroke injection mode to the intake stroke injection mode causes a step-like increase in engine torque, but is temporarily controlled in the torque decreasing direction by the above-described opening side correction of the vane opening degree. The engine torque increases smoothly with mode switching. Similarly, switching from the intake stroke injection mode to the compression stroke injection mode causes a stepwise decrease in the engine torque, but the engine torque decreases smoothly because it is controlled in the direction of increasing the torque by the closing correction of the vane opening. Is done.
[0027]
Therefore, in the engine 1 of the second embodiment, in addition to the operations and effects described in the first embodiment, it is possible to suppress a sudden change in engine torque that occurs at the time of mode switching and to realize a favorable operating environment. .
[Third embodiment]
A third embodiment in which the present invention is embodied in another in-cylinder injection engine 1 will be described below. The basic configuration of the engine 1 of the present embodiment, the control contents based on the main routine of FIG. 3, the map characteristics of FIG. 2, and the like are the same as those of the first embodiment, and the difference relates to the vane control of the turbocharger 10. The point is to implement a countermeasure against failure. Therefore, the difference will be described mainly.
[0028]
The ECU 31 executes the failure control routine shown in FIG. 5 at a predetermined control interval. Here, for convenience of explanation, in the compression stroke injection mode of FIG. 2, an area corresponding to the NA engine (inside the two-dot chain line) is A, and an area enlarged by supercharging is B. The ECU 31 first inputs the supercharging pressure Pb of the turbocharger 10 from the supercharging pressure sensor 34 in step S22, and determines in step S24 whether or not the operating state of the engine 1 is within the B region of the compression stroke injection mode. . If YES, the difference ΔPb between the actual boost pressure Pb and the target boost pressure is calculated in step S26, and the difference ΔPb is compared with preset determination values ΔPb0 and −ΔPb0 in step S28 to determine the difference ΔPb. When it is within the values ΔPb0 and −ΔPb0, the routine is terminated as it is.
[0029]
If the difference ΔPb is equal to or less than the determination value −ΔPb0 and exceeds the normal range and the boost pressure Pb is low, the vane opening is corrected to full open in step S30, and the control map of FIG. The engine characteristic, that is, the characteristic in which the region B is set to the region in the intake stroke injection mode is changed, and the routine is terminated. As a result, in step S8 of the main routine shown in FIG. 3, each control amount is set in the intake stroke injection mode and on the premise that the vane is fully opened.
[0030]
On the other hand, if the difference ΔPb is equal to or larger than the determination value ΔPb0 in step S28 and exceeds the normal range and the boost pressure Pb is high, the process proceeds to step S34, and each control amount set in step S8 of the main routine. Is corrected based on the difference ΔPb. This correction process is for correcting an increase in engine torque caused by excessive supercharging pressure Pb, and each control amount is corrected in a direction to suppress the engine torque.
[0031]
When the determination in step S24 is NO, that is, when the operating state of the engine 1 is in the region A or the intake stroke injection mode, the boost pressure Pb is set in step S36 in the same manner as in step S26. A difference ΔPb from the target boost pressure is calculated. Next, in step S38, it is determined whether or not the difference ΔPb is within the determination values ΔPb0 and −ΔPb0. If YES, the routine ends. Note that, as the determination values ΔPb0 and −ΔPb0 at this time, values different from those in step S26 may be used. When the determination in step S38 is NO, each control amount in step S8 is corrected based on the difference ΔPb in step S34. The purpose of this correction process is the same as in step S34, and is for correcting fluctuations in engine torque due to excessive or excessive supercharging pressure Pb. In the present embodiment, the ECU 31 when executing the processing of the above steps S28 to S32 functions as a failure time control means.
[0032]
Here, as detailed in the first embodiment, the stratified combustion is realized by supercharging in the B region. Accordingly, if the supercharging pressure Pb becomes excessively low due to some factor during the operation in the region B and the supercharging pressure Pb becomes excessively small, the amount of oxygen is insufficient with respect to the amount of fuel, and is appropriately disposed around the spark plug 3. Thus, an incomplete combustion is caused without forming a proper air-fuel ratio mixture. In this embodiment, when such a situation occurs, after the insufficient supercharging is stopped as described above and the non-supercharging operation similar to that of the NA engine is performed, the intake air is drawn based on the control map for the NA engine. Since it is switched to uniform combustion in the stroke injection mode, the injected fuel can be reliably ignited and burned.
[0033]
Therefore, in the engine of the third embodiment, in addition to the operations and effects described in the first embodiment, even when the abnormality occurs in the vane control of the turbocharger 10 and the supercharging pressure is insufficient, B Smoke generation due to incomplete combustion in the region can be prevented in advance.
[Fourth embodiment]
A fourth embodiment in which the present invention is embodied in another in-cylinder injection engine 1 will be described below. The basic configuration of the engine 1 of the present embodiment, the control contents based on the main routine of FIG. 3, the map characteristics of FIG. 2, etc. are the same as those of the first embodiment, and the difference depends on the accelerator operation amount APS. This is to change the region of the compression stroke injection mode and the intake stroke injection mode. Therefore, the difference will be described mainly.
[0034]
The ECU 31 executes the acceleration control routine shown in FIG. 6 at a predetermined control interval. First, in step S42, it is determined whether or not the current fuel injection mode is the compression stroke injection mode. In step S44, a determination value in which the change rate ΔAPS of the accelerator operation amount APS is set in advance as a value corresponding to rapid acceleration. It is determined whether it is greater than or equal to ΔAPS0. If any determination is NO, the routine is terminated as it is.
[0035]
If both the determinations in steps S42 and S44 are YES, the control map of FIG. 2 is changed to a characteristic in which the B region is set to the intake stroke injection mode region in step S46, and the vane opening is set to the open side in step S48. After correction, the routine is terminated. The correction amount of the vane opening is set to an amount corresponding to the difference in engine torque between stratified combustion and uniform combustion. As a result, the torque increase when switching from stratified combustion to uniform combustion is caused by the decrease in supercharging pressure Pb. Absorbed.
[0036]
Therefore, when the rapid acceleration is performed within the compression stroke injection mode region (regardless of the A region or the B region), the region B is switched to the intake stroke injection mode by the process of step S46. During such sudden acceleration, the operating state normally shifts from the compression stroke injection mode region to the O / L mode side in the direction of increasing the target average effective pressure Pe in FIG. Although acceleration is performed with the engine torque generated by uniform combustion based on the fuel ratio, it passes through the B region in the acceleration process. Since the B region is switched to the intake stroke injection mode as described above, the switching from the stratified combustion to the uniform combustion is performed at an earlier timing of the boundary between the A region and the B region. In response to the prompt launch.
[0037]
Since the determination in step S44 is NO during slow acceleration, the map characteristics are not changed in step S46, and stratified combustion is continued until the upper limit timing of the B region, thereby reducing CO and HC and improving fuel efficiency. It is done. In the present embodiment, the ECU 31 when executing the processes of steps S42 to S48 described above functions as an acceleration control unit.
[0038]
As described above, in the engine of the fourth embodiment, in addition to the operations and effects described in the first embodiment, the B region is switched from the stratified combustion to the uniform combustion at the time of sudden acceleration, so the uniform combustion starts at an earlier timing. As a result, the engine torque can be quickly raised and a very good acceleration feeling can be realized.
This is the end of the description of the embodiment. However, the embodiment of the present invention is not limited to this embodiment. For example, in the first embodiment, the engine 1 includes the turbocharger 10 capable of adjusting the supercharging pressure. However, in the first embodiment, it is not necessary to positively adjust the supercharging pressure in accordance with the operating state. Therefore, it may be replaced with a normal turbocharger whose boost pressure is uniquely determined according to the operating state of the engine 1 or a supercharger driven by a crankshaft.
[0039]
In the second to third embodiments, the supercharging pressure adjusting means capable of adjusting the supercharging pressure is the vane 19. However, when a normal turbocharger is used, the supercharging pressure adjusting means is used as the wastegate. The present invention can be implemented as a valve. Specifically, in the third embodiment, for example, when a phenomenon occurs in which the wastegate valve is fixed on the open side and the supercharging pressure Pb is insufficient, the control map is determined because the supercharging operation has already been performed. By switching to the characteristic for the NA engine and making the B region uniform combustion, incomplete combustion when the supercharging pressure adjusting means fails can be prevented as in the third embodiment.
[0040]
On the other hand, in each of the above embodiments, it is embodied as an in-cylinder injection type engine that directly injects into the cylinder. If it is, it will not be limited to a cylinder injection type engine. Therefore, for example, the present invention may be embodied as an intake pipe injection type lean burn engine that performs stratified combustion using swirl, tumble flow, or the like, and a turbocharger or the like may be combined to expand the stratified combustion region by supercharging.
[0041]
【The invention's effect】
As described above, according to the internal combustion engine of the first aspect of the present invention, smoke is prevented from being generated due to incomplete combustion, and the operating range in which stratified combustion is possible is expanded to the high load side to further improve fuel efficiency. It can be achieved, and torque fluctuations that occur when the operating state is switched can be suppressed to achieve a favorable operating environment , and even if there is an abnormality in the supercharging means and the supercharging pressure is insufficient, Smoke generation due to complete combustion can be prevented in advance .
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing an internal combustion engine of an embodiment.
FIG. 2 is an explanatory diagram showing a map for determining a fuel injection mode.
FIG. 3 is a flowchart showing a main routine executed by the ECU.
FIG. 4 is a flowchart showing a transient control routine executed by the ECU.
FIG. 5 is a flowchart showing a failure time control routine executed by the ECU.
FIG. 6 is a flowchart showing an acceleration control routine executed by the ECU.
[Explanation of symbols]
1 engine (internal combustion engine)
10 Turbocharger (supercharging means)
19 Vane (supercharging pressure adjustment means)
21 Vane adjustment actuator (supercharging pressure adjustment means)
31 ECU (operating state switching means, transient control means, failure time control means, acceleration time control means)

Claims (1)

Supercharging means for supercharging intake air of the internal combustion engine;
Operation state switching for switching the operation state of the internal combustion engine between a first operation state that is set to include a supercharging region by the supercharging means and executes stratified combustion and a second operation state that performs uniform combustion Means,
A supercharging pressure adjusting means capable of adjusting a supercharging pressure of the supercharging means;
When the operation state switching means switches between the first operation state and the second operation state, the supercharging is performed so that the second operation state side has a low supercharging pressure with respect to the first operation state. Transient control means for controlling the pressure adjusting means ;
When the desired supercharging pressure is not reached in the supercharging region of the supercharging means in the first operating state, the supercharging pressure is reduced by the supercharging pressure adjusting means, and the operating state switching means is used to reduce the supercharging pressure. An internal combustion engine comprising : a failure time control means for switching a specific region of one operating state to a second operating state .

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