JP4254021B2 - Catalyst early warm-up control device for in-cylinder internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst early warm-up control device for a direct injection internal combustion engine having a function of warming up an exhaust gas purifying catalyst early in a direct injection internal combustion engine.
[0002]
[Prior art]
In a cylinder injection internal combustion engine (direct injection engine), purification of exhaust gas is performed by a catalyst as in the case of an intake pipe injection engine. However, if the catalyst does not rise to the activation temperature, the exhaust gas is exhausted. Therefore, it is desirable to perform early catalyst warm-up control that raises the exhaust gas temperature after startup and raises the catalyst temperature to the activation temperature early after starting. In an intake pipe injection engine, early catalyst warm-up control is performed by ignition delay angle control or the like, but in a direct injection engine, as shown in JP-A-4-183922, the upstream side of the catalyst in the exhaust pipe is ignited. When a catalyst is provided and the temperature of the catalyst is lower than a predetermined temperature, additional fuel is injected in the expansion stroke or exhaust stroke to mix the fuel into the exhaust gas, and this is ignited by the ignition device in the exhaust pipe and burned. There is one in which the exhaust temperature is raised to warm up the catalyst.
[0003]
However, in this configuration, it is necessary to provide an ignition device in the exhaust pipe, and there is a disadvantage that the cost increases accordingly.
[0004]
In order to eliminate this drawback, as shown in Japanese Patent Application Laid-Open No. 8-291729, after the main injection for generating the engine output in the compression stroke, the post-injection is performed in the expansion stroke, and the combustion heat of the main injection fuel The post-injected fuel is burned to increase the exhaust temperature and promote the warm-up of the catalyst.
[0005]
[Problems to be solved by the invention]
Even in a direct injection engine, since the fuel pressure is low at the time of start-up and the required injection amount is large, fuel is injected during the intake stroke to perform homogeneous combustion. Therefore, when starting, even if the catalyst is inactive, operate in homogeneous combustion mode, and after starting, switch to stratified combustion mode where fuel is injected in the compression stroke and stratified combustion is performed in the compression stroke As described in the above publication, there is a type in which the catalyst is warmed up by performing post-injection in the expansion stroke.
[0006]
However, when switching from the homogeneous combustion mode to the stratified combustion mode, the air system such as the throttle valve is largely switched, so that there is a considerable delay in switching the air system. That is, after switching from the homogeneous combustion mode to the stratified combustion mode, there is a considerable delay in increasing the amount of air charged in the cylinder to the target value. Therefore, immediately after switching to the stratified combustion mode, if the post-injection is started with the post-injection amount at the time of normal stratified combustion, the amount of air (oxygen amount) in the cylinder is insufficient and the fuel of the post-injection is burned sufficiently This results in worse exhaust emissions.
[0007]
Therefore, it is conceivable to delay the start timing of the post-injection by the delay of the air system. However, in the stratified combustion mode, since a large amount of air is sucked into the cylinder and discharged, the start timing of the post-injection (the exhaust temperature rise) If the temperature start time) is delayed, the exhaust temperature decreases immediately after switching to the stratified combustion mode, the exhaust temperature is lowered, the catalyst is cooled, the catalyst warm-up is increasingly delayed, and the exhaust emission is deteriorated. .
[0008]
Moreover, since the in-cylinder temperature is low immediately after starting, the period during which the post-injected fuel can be ignited by the combustion heat of the main injected fuel is shortened. For this reason, if the post-injection is started at the post-injection timing at the time of normal stratified combustion immediately after switching to the stratified combustion mode, there is a possibility that the fuel of the post-injection cannot be ignited by the combustion heat of the main injection fuel.
[0009]
The present invention has been made in view of such circumstances. Therefore, even if the post-injection is started immediately after switching to the stratified combustion mode, the post-injection fuel can be sufficiently burned. Thus, an object of the present invention is to provide a catalyst early warm-up control device for a direct injection internal combustion engine that can improve early catalyst warm-up performance and reduce exhaust emission.
[0010]
[Means for Solving the Problems]
[0012]
In addition, since the in-cylinder temperature is low immediately after start-up, considering that the period in which the post-injected fuel can be ignited by the combustion heat of the main injected fuel is shortened, the early warm-up of the catalyst is performed as in claim 1. when required, a predetermined time period from switching to the stratified combustion mode to the in-cylinder temperature is raised to a predetermined temperature you correct advancing the post injection timing. Here, the “predetermined period” may be set in consideration of the period until the in-cylinder temperature rises to the in-cylinder temperature during normal stratified combustion. If the post-injection timing is corrected to advance during this period and the post-injection timing is brought close to the combustion timing of the main injection fuel, the combustion heat of the main injection fuel can be obtained even when the in-cylinder temperature is low immediately after switching to the stratified combustion mode. Thus, the post-injection can be performed at a time when the post-injected fuel can be ignited. This makes it possible to reliably burn the post-injected fuel immediately after switching to the stratified combustion mode and to promote warm-up of the catalyst. Further, in the invention according to claim 1 , the post-injection is performed so that the fuel injected later is ignited and burned in the cylinder for a predetermined period from when the stratified combustion mode is switched to when the in-cylinder temperature rises to the predetermined temperature. The timing is corrected to advance.
[0013]
In this case, the advance angle correction amount of the post injection timing may be a fixed value, but as in claim 2 , the advance angle correction amount of the post injection timing is set according to the deviation between the control target value of the air system and the actual measurement value. You may make it do. In this way, the advance angle correction amount of the post injection timing can be optimized by following the rise in the in-cylinder temperature (increase in the in-cylinder charged air amount) immediately after switching to the stratified combustion mode, and the catalyst early The effect of improving warm-up performance and reducing exhaust emissions can be increased.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment (1)]
Hereinafter, an embodiment (1) of the present invention will be described with reference to FIGS.
First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the direct injection engine 11 that is a direct injection internal combustion engine. A throttle valve 15 whose opening degree is adjusted by a step motor 14 is provided downstream of the air cleaner 13. Is provided. The step motor 14 is driven based on an output signal from an engine electronic control circuit (hereinafter referred to as “ECU”) 16, whereby the opening (throttle opening) of the throttle valve 15 is controlled. Accordingly, the intake air amount to each cylinder is adjusted. A throttle sensor 17 for detecting the throttle opening is provided in the vicinity of the throttle valve 15.
[0015]
A surge tank 19 is provided downstream of the throttle valve 15, and an intake manifold 20 that introduces air into each cylinder of the engine 11 is connected to the surge tank 19. A first intake passage 21 and a second intake passage 22 are respectively formed in the intake manifold 20 of each cylinder, and the first intake passage 21 and the second intake passage 22 are formed in each cylinder of the engine 11. The two intake ports 23 are connected to each other. A swirl control valve 24 is disposed in the second intake passage 22 of each cylinder. The swirl control valve 24 of each cylinder is connected to a step motor 26 via a common shaft 25. The step motor 26 is driven based on an output signal from the ECU 16 to control the opening degree of the swirl control valve 24, and the swirl flow intensity in each cylinder is adjusted according to the opening degree. A swirl control valve sensor 27 that detects the opening degree of the swirl control valve 24 is attached to the step motor 26.
[0016]
A fuel injection valve 28 for directly injecting fuel into the cylinder is attached to the upper part of each cylinder of the engine 11. The fuel sent from the fuel tank (not shown) to the fuel delivery pipe 29 through the fuel pipe 45 is injected into the combustion chamber from the fuel injection valve 28 of each cylinder and mixed with the intake air introduced from the intake port 23. As a result, an air-fuel mixture is formed. A fuel pressure sensor 30 for detecting the fuel pressure is attached to the fuel delivery pipe 29.
[0017]
Further, an ignition plug (not shown) is attached to the cylinder head of the engine 11 for each cylinder, and the air-fuel mixture in the combustion chamber is ignited by ignition of each ignition plug. The cylinder discrimination sensor 32 outputs a pulsed cylinder discrimination signal when the specific cylinder reaches the intake top dead center, and the crank angle sensor 33 sets the crankshaft of the engine 11 to a predetermined crank angle (for example, 30 ° C.). Each time the engine rotates, a pulsed crank angle signal is output, and the engine speed is detected based on the output frequency of the crank angle signal. Further, crank angle detection and cylinder discrimination are performed based on the crank angle signal and the cylinder discrimination signal.
[0018]
On the other hand, an exhaust pipe 37 is connected to the exhaust port 35 of the engine 11 via an exhaust manifold 36. In the exhaust pipe 37, a three-way catalyst 38 for efficiently purifying exhaust gas in the vicinity of the stoichiometric air-fuel ratio and a NOx occlusion type lean NOx catalyst 39 are arranged in series. The lean NOx catalyst 39 adsorbs NOx in the exhaust during lean operation where the oxygen concentration in the exhaust is high, and reduces the adsorbed NOx when the air-fuel ratio is switched to rich and the oxygen concentration in the exhaust decreases. Purify and release. A NOx concentration sensor (not shown) for detecting the NOx concentration in the exhaust gas flowing out from the lean NOx catalyst 39 is installed on the downstream side of the lean NOx catalyst 39, and the lean NOx catalyst 39 estimated from the NOx concentration in the exhaust gas. When the amount of NOx adsorbed exceeds a predetermined value, the air-fuel ratio is temporarily switched from lean to rich.
[0019]
Further, an EGR pipe 40 that recirculates a part of the exhaust gas is connected between the upstream side of the three-way catalyst 38 in the exhaust pipe 37 and the surge tank 19, and an EGR amount ( An EGR valve 41 for controlling the exhaust gas recirculation amount is provided. The accelerator pedal 18 is provided with an accelerator sensor 42 that detects the accelerator opening.
[0020]
Output signals from the various sensors described above are input to the ECU 16. The ECU 16 is mainly composed of a microcomputer, and in accordance with a control program stored in a built-in ROM (storage medium), based on various sensor outputs, the step motors 14 and 26, the EGR valve 41, and the fuel injection valve 28 described above. Control the operation of the spark plug. For example, during low / medium load operation, a small amount of fuel is injected in the compression stroke so that the air-fuel ratio becomes lean, and a thicker air-fuel mixture is formed around the spark plug to cause stratified combustion. Let the air-fuel ratio as a whole be lean (stratified combustion mode). Further, at the time of high load operation or at the time of start-up, the fuel injection amount is increased so as to be near or slightly richer than the theoretical air-fuel ratio, and fuel is injected in the intake stroke to perform homogeneous combustion (homogeneous combustion mode). Thus, the function of the ECU 16 for switching the combustion mode plays a role corresponding to the combustion mode switching means in the claims.
[0021]
Further, the ECU 16 executes the catalyst early warm-up control program shown in FIG. 2 to switch to the stratified combustion mode to generate engine output in the compression stroke when the early warm-up of the three-way catalyst 38 is required. After performing the main injection, post-injection is performed in the expansion stroke (see FIG. 5), and the post-injection fuel is combusted by the combustion heat of the main injection fuel to raise the exhaust gas temperature. Further, during the early catalyst warm-up control, the post-injection amount is corrected to decrease and the post-injection timing is advanced by a predetermined period after switching to the stratified combustion mode (see FIG. 4). Hereinafter, processing contents of the catalyst early warm-up control program will be described.
[0022]
This program is started at every predetermined crank angle after an ignition switch (not shown) is turned on, and serves as a catalyst early warm-up control means in the claims. When this program is started, first, in step 101, it is determined whether or not the three-way catalyst 38 is in an activated state based on whether or not the catalyst temperature is equal to or higher than the activation lower limit temperature (for example, 200 ° C.). The catalyst temperature may be detected using a catalyst temperature sensor (not shown) installed on the three-way catalyst 38, or the catalyst temperature may be estimated from the cooling water temperature and the elapsed time after starting.
[0023]
If it is determined in step 101 that the three-way catalyst 38 is in an active state, it is not necessary to perform early catalyst warm-up control, so the routine proceeds to step 102 and the count value of the elapsed time counter CCNG after stratified combustion mode switching is reached. Is reset to 0 and the program is terminated. The elapsed time counter CCNG after switching the stratified combustion mode is a counter that counts the elapsed time after switching the stratified combustion mode.
[0024]
On the other hand, if the three-way catalyst 38 is not yet activated, the routine proceeds to step 103, where it is determined whether or not a post-injection execution condition (catalyst early warm-up control execution condition) is satisfied. Here, the post-injection execution condition is an operation state in which stable combustion is possible even when the post-injection is performed after switching to the stratified combustion mode. For example, as shown in FIG. A region where the engine load is small may be determined as the post-injection execution region, or the post-injection execution condition may be a light load region and a predetermined time or more after the start.
[0025]
Even after the start, if the post-injection execution condition is not satisfied, the post-injection (catalyst early warm-up control) is not performed, and the count value of the elapsed time counter CCNG after stratified combustion mode switching is reset to 0 (step 102). ), This program ends.
[0026]
On the other hand, if the post-injection execution condition is satisfied, the process proceeds to step 104, where it is determined whether or not the current combustion mode is the stratified combustion mode. The mode is switched from the homogeneous combustion mode to the stratified combustion mode, the count value of the elapsed time counter CCNG after switching to the stratified combustion mode is reset to 0 (step 106), and this program is terminated.
[0027]
On the other hand, after the post-injection execution condition is established and the stratified combustion mode is switched, the routine proceeds to step 107, where the post-injection amount Q2ND and the post-injection timing A2ND are calculated from a map or the like according to the current engine operating state ( The post-injection timing A2ND is set based on, for example, the compression top dead center). Thereafter, the routine proceeds to step 108, where it is determined whether or not the count value of the elapsed time counter CCNG after switching to the stratified combustion mode is greater than or equal to a predetermined value B, that is, whether or not the elapsed time after switching to the stratified combustion mode has exceeded a predetermined time. To do. Here, the predetermined value B is set to a value corresponding to a period during which an air system delay (oxygen supply amount delay) occurs after switching to the stratified combustion mode.
[0028]
Therefore, if the count value of the elapsed time counter CCNG after switching to the stratified combustion mode is less than the predetermined value B, the air system has been delayed after switching to the stratified combustion mode. After the combustion mode switching elapsed time counter CCNG is incremented, the routine proceeds to step 110 where the post-injection amount Q2ND is corrected to decrease in consideration of the delay of the air system after switching to the stratified combustion mode, and the post-injection timing A2ND is set. Correct the advance angle.
[0029]
At this time, the reduction correction of the post-injection amount Q2ND is performed by multiplying the post-injection amount Q2ND obtained in step 107 by the correction coefficient K1 (K1 <1.0), and the advance angle correction of the post-injection timing A2ND is performed in step 107. This is performed by subtracting the advance angle correction amount T1 from the post-injection timing A2ND obtained in the above. Here, although the correction coefficient K1 and the advance correction amount T1 may be fixed values, they may be changed according to the count value of the elapsed time counter CCNG after stratified combustion mode switching. For example, as the count value of the elapsed time counter CCNG after switching to the stratified combustion mode increases, the correction coefficient K1 is increased to reduce the decrease correction amount of the post-injection amount Q2ND and the advance angle correction amount T1 (FIG. 4). reference).
[0030]
Reduction correction of the post-injection amount Q2ND and advance angle correction of the post-injection timing A2ND are performed until the count value of the elapsed time counter CCNG after stratified combustion mode switching reaches the predetermined value B. As a result, the reduction correction of the post-injection amount Q2ND and the advance angle correction of the post-injection timing A2ND are performed during a period in which the air system delay occurs after switching to the stratified combustion mode.
[0031]
Thereafter, when the count value of the elapsed time counter CCNG after switching to the stratified combustion mode reaches the predetermined value B, the count value of the counter CCNG is fixed to the predetermined value B (step 110), the post-injection amount Q2ND is decreased and corrected. The advance angle correction at time A2ND is terminated. Thus, after the delay of the air system can be ignored, the post-injection is performed at the post-injection amount Q2ND and the post-injection timing A2ND obtained in step 107. The post-injected fuel is ignited and burned by the combustion heat of the main injection fuel, and the exhaust temperature is raised to promote the warm-up of the three-way catalyst 38.
[0032]
An execution example of the catalyst early warm-up control of the present embodiment (1) described above will be described with reference to the time chart of FIG. When the engine is started, the post-injection execution condition (catalyst early warm-up control execution condition) is not satisfied, and the engine 11 is started in the homogeneous combustion mode. When the post-injection execution condition is satisfied after the start, the required combustion mode is switched to the stratified combustion mode, and the air system (throttle valve 15, swirl control valve 24, etc.) is immediately switched to the control target value for stratified combustion. At this time, at the same time as the required combustion mode is switched to the stratified combustion mode, the target value of the intake air amount increases in a stepped manner. However, since the air system is delayed, the actual intake air amount is delayed with respect to the target value. Increase.
[0033]
Slightly after the switching of the air system (switching of the target value of the intake air amount), the main injection timing is switched to the compression stroke and switched to stratified combustion, and at the same time, the post-injection is started. Immediately after switching to stratified combustion, the intake air amount has not yet increased to the target value, so if the post-injection is started at the post-injection amount during normal stratified combustion immediately after switching to stratified combustion, the amount of air in the cylinder The (oxygen amount) is insufficient, and the post-injected fuel cannot be combusted sufficiently, resulting in a deterioration in exhaust emission.
[0034]
Therefore, in the present embodiment (1), the period until the predetermined time B elapses after switching to stratified combustion (compression stroke injection), that is, the period until the intake air amount increases to near the target value is Correct the injection amount to decrease. As a result, the post-injection amount can be reduced to an appropriate injection amount that takes into account the delay of the air system, so even if the post-injection is started immediately after switching to stratified combustion, the post-injection is performed with respect to the actual cylinder air charge The amount of fuel does not become excessive, the post-injection fuel can be burned reliably, the warming-up of the three-way catalyst 38 can be promoted by increasing the exhaust temperature by post-injection immediately after switching to stratified combustion, Exhaust emissions can be reduced.
[0035]
Further, in consideration of the fact that the in-cylinder temperature is low immediately after the start of post-injection (immediately after switching to stratified combustion), the period in which the post-injected fuel can be ignited by the combustion heat of the main injected fuel is shortened. In (1), the post-injection timing is corrected to advance during a period from when switching to stratified combustion until a predetermined time B has elapsed. As a result, the injection timing can be brought close to the combustion timing of the main injection fuel, so that even when the in-cylinder temperature immediately after switching to stratified combustion is low, the timing is such that the post-injection fuel can be ignited by the combustion heat of the main injection fuel. The post-injection can be performed, and the fuel of the post-injection can be surely burned immediately after switching to the stratified combustion mode, and the warm-up of the three-way catalyst 38 can be promoted.
[0036]
In the present embodiment (1), both the post-injection amount reduction correction and the post-injection timing advance correction are performed during a period from when switching to stratified combustion (compression stroke injection) until a predetermined time B has elapsed. Although implemented, only one of them may be implemented. Further, when both the post-injection amount reduction correction and the post-injection timing advance correction are performed, the time for performing the post-injection amount reduction correction and the time for performing the post-injection timing advance correction may be different. For example, the latter may be shorter than the former.
[0037]
[Embodiment (2)]
In the above embodiment (1), the post-injection amount reduction correction amount and the post-injection timing advance correction amount are set by the elapsed time after switching to stratified combustion. However, the embodiment of the present invention shown in FIGS. In the form (2), the reduction correction amount of the post injection amount and the advance correction amount of the post injection timing are set according to the deviation between the target value of the intake air amount and the actual measurement value.
[0038]
In the present embodiment (2), the catalyst early warm-up control is performed as follows by the program of FIG. First, in step 201, it is determined whether or not the three-way catalyst 38 is in an activated state. If the three-way catalyst 38 is already in an activated state, the program is terminated without performing the subsequent processing. To do.
[0039]
On the other hand, if the three-way catalyst 38 is not yet activated, the routine proceeds to step 202, where the post injection execution condition (catalyst early warm-up control execution condition) is established by the same method as in the embodiment (1). Determine whether or not. If the post-injection execution condition is not satisfied, the program is terminated without performing the subsequent processing.
[0040]
On the other hand, if the post-injection execution condition is satisfied, the process proceeds to step 203, where it is determined whether or not the current combustion mode is the stratified combustion mode. The mode is changed from the homogeneous combustion mode to the stratified combustion mode, and this program is terminated.
[0041]
On the other hand, after the post-injection execution condition is satisfied and the stratified combustion mode is switched to, the routine proceeds to step 205 where the post-injection amount Q2ND and the post-injection timing A2ND are calculated from a map or the like according to the current engine operating state. Thereafter, the routine proceeds to step 206, where it is determined whether or not the actual intake air amount measured by the intake air amount sensor (not shown) has increased to the vicinity of the target intake air amount.
Actual intake air amount ≥ Target intake air amount-α
Here, α is a correction coefficient for allowing detection error of the intake air amount sensor. The target intake air amount is set by the ECU 16 (control target value setting means).
[0042]
If the actual intake air amount <target intake air amount−α, the actual intake air amount has not yet increased to the vicinity of the target intake air amount (the delay in the air system cannot be ignored). The injection amount reduction correction amount Qs and the post-injection timing advance correction amount Ts are calculated according to the deviation between the target intake air amount and the actual intake air amount using the maps shown in FIGS. As a result, the larger the deviation between the target intake air amount and the actual intake air amount, the larger the post-injection amount decrease correction amount Qs and the post-injection timing advance correction amount Ts.
[0043]
Thereafter, the process proceeds to step 209, where the post-injection amount Q2ND obtained in step 205 is reduced by a reduction correction amount Qs (Q2ND ← Q2ND−Qs), and the post-injection timing A2ND obtained in step 205 is further advanced. The advance angle is corrected by Ts (A2ND ← A2ND−Ts).
[0044]
Thereafter, when the actual intake air amount increases to near the target intake air amount, the process proceeds from step 206 to step 208, where both the reduction correction amount Qs and the advance correction amount Ts are set to zero. Thus, the reduction correction of the post injection amount Q2ND and the advance angle correction of the post injection timing A2ND are finished, and the post injection is performed at the post injection amount Q2ND and the post injection timing A2ND obtained in step 205.
[0045]
In the present embodiment (2) described above, the post-injection amount reduction correction amount Qs and the post-injection timing advance correction amount Ts are set according to the deviation between the target intake air amount and the actual intake air amount. Improving the post-injection amount decrease correction amount Qs and the post-injection timing advance correction amount Ts by following the actual increase in the in-cylinder charged air amount and the increase in the in-cylinder temperature immediately after switching to the stratified combustion mode. The effect of improving the catalyst early warm-up performance and reducing exhaust emissions can be increased.
[0046]
In this embodiment (2), the deviation between the target intake air amount and the actual intake air amount is used as a parameter for evaluating the delay of the air system after switching the stratified combustion mode. A deviation from the intake pipe pressure or a deviation between the target throttle opening and the actual throttle opening may be used.
[0047]
Further, in the present embodiment (2), both the post-injection amount decrease correction and the post-injection timing advance correction are performed, but only one of them may be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an entire engine control system in an embodiment (1) of the present invention. FIG. 2 is a flowchart showing a process flow of a catalyst early warm-up control program in an embodiment (1). FIG. 4 is a diagram conceptually showing a map for determining a post-injection execution region. FIG. 4 is a time chart showing an execution example of catalyst early warm-up control in the embodiment (1). FIG. 5 is a main injection, post-injection, and in-cylinder temperature. FIG. 6 is a flowchart showing the flow of processing of the catalyst early warm-up control program of the embodiment (2). FIG. 7 is a post-injection amount based on a deviation between the target intake air amount and the actual intake air amount. FIG. 8 is a diagram conceptually showing a map for obtaining a reduction correction amount Qs of the engine. FIG. 8 is a diagram conceptually showing a map for obtaining the advance correction amount Ts of the post injection timing from the deviation between the target intake air amount and the actual intake air amount. Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Direct injection engine (cylinder injection internal combustion engine), 12 ... Intake pipe, 15 ... Throttle valve, 16 ... ECU (combustion mode switching means, catalyst early warm-up control means, control target value setting means), 24 ... Swirl Control valve, 28 ... Fuel injection valve, 37 ... Exhaust pipe, 38 ... Three-way catalyst, 39 ... Lean NOx catalyst, 41 ... EGR valve.

Claims (2)

In a cylinder injection internal combustion engine in which fuel is directly injected from a fuel injection valve into a cylinder and burned, and the exhaust gas is purified by a catalyst.
Combustion mode switching means for switching between a homogeneous combustion mode for injecting fuel in the intake stroke and performing homogeneous combustion and a stratified combustion mode for injecting fuel in the compression stroke and for performing stratified combustion in accordance with the operating state;
When the catalyst is required to be warmed up early, the catalyst is warmed up by switching to the stratified combustion mode and performing the main injection for generating the engine output in the compression stroke and then performing the post-injection in the expansion stroke to increase the exhaust temperature. Control means,
The catalyst early warm-up control means is configured such that when the catalyst is required to be warmed up early, the post-injected fuel is injected into the cylinder for a predetermined period after switching to the stratified combustion mode until the in-cylinder temperature rises to a predetermined temperature. A catalyst early warm-up control device for a cylinder injection internal combustion engine, wherein the post-injection timing is corrected so as to ignite and burn in the cylinder. Control target value setting means for setting a control target value of the air system according to the operating state,
2. The in-cylinder according to claim 1 , wherein the catalyst early warm-up control unit sets an advance correction amount of the post-injection timing according to a deviation between a control target value of the air system and an actual measurement value. A catalyst early warm-up control device for an injection internal combustion engine.

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