JP2012163010A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine having a manifold injection valve and an in-cylinder direct-injection valve, and capable of adequately and efficiently performing manifold injection and in-cylinder direct-injection.SOLUTION: When fuel is injected from both a first fuel injection valve for injecting fuel in an air intake passage of an internal combustion engine and a second fuel injection valve for injecting fuel directly in a combustion chamber of the internal combustion engine, the fuel injection amount from the first and second fuel injection valves is set based on the intake air volume to be measured during the expansion stroke (the measurement period A). When it is detected that the internal combustion engine is in an accelerated/decelerated state, the fuel injection amount of the in-cylinder intake stroke injection and the in-cylinder compression stroke injection from the second fuel injection valve is corrected based on the intake air volume to be measured during the exhaust stroke (the measurement period B) and the intake stroke (the measurement period C).

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a fuel injection control technique for an internal combustion engine capable of performing both intake pipe injection and in-cylinder injection.

2. Description of the Related Art Recently, an internal combustion engine control apparatus that includes an intake pipe injection valve and an in-cylinder injection valve in a multi-cylinder internal combustion engine and can perform both intake pipe injection and in-cylinder injection in accordance with the operating state of the internal combustion engine Has been developed.
Usually, in an internal combustion engine, the fuel injection amount is set based on the intake air amount. In the internal combustion engine having the intake pipe injection valve and the in-cylinder injection valve, the intake pipe injection is performed one stroke before the intake pipe injection. For example, based on the intake air amount measured during the expansion stroke, the fuel injection amount is set based on the intake air amount measured during the intake stroke, for example, one stroke before the in-cylinder injection. is doing.

  Then, in the case of performing both intake pipe injection and in-cylinder injection, after obtaining the fuel injection amount based on the intake air amount, the fuel injection amount in the in-cylinder injection is corrected according to the change in the intake air amount The apparatus of this is disclosed (patent document 1).

JP 2008-75514 A

However, when both intake pipe injection and in-cylinder injection are performed, the technique disclosed in Patent Document 1 always calculates the intake air amount for correcting the fuel injection amount from the in-cylinder injection valve. Thus, even when the internal combustion engine is in a steady operation state and correction is not necessary, the amount of intake air for correction is calculated.
Implementation of such unnecessary calculations increases the burden of calculation processing, is not efficient, and is not preferable.

  Further, in an internal combustion engine having a variable valve timing device capable of varying the opening / closing timing of the intake valve and the exhaust valve, the intake air amount varies depending on the overlap amount of the opening / closing timing of the intake valve and the exhaust valve. Therefore, especially when the intake air amount changes greatly as in acceleration / deceleration, it is desirable to use the intake air amount measured by an air flow sensor or the like provided in the intake passage for calculation as it is, which causes an error in the fuel injection amount. Not that.

  An object of the present invention is to provide a control device for an internal combustion engine that includes an intake pipe injection valve and an in-cylinder injection valve, and that can efficiently perform intake pipe injection and in-cylinder injection appropriately.

  In order to achieve the above object, a control apparatus for an internal combustion engine according to claim 1 includes a first fuel injection valve that injects fuel into an intake passage of the internal combustion engine, and a second fuel injection that directly injects fuel into a combustion chamber of the internal combustion engine. A valve, intake air amount measuring means for measuring the intake air amount into the combustion chamber, and fuel injection control means for controlling fuel injection injected from the first and second fuel injection valves in accordance with the operating state of the internal combustion engine And an acceleration / deceleration state detection means for detecting that the internal combustion engine is in an acceleration / deceleration state, wherein the fuel injection control means is configured to inject the intake when fuel is injected from both the first and second fuel injection valves. A fuel injection amount to be injected from the first and second fuel injection valves is set based on the intake air amount measured during the expansion stroke by the air amount measuring means, and the internal combustion engine is accelerated / decelerated by the acceleration / deceleration state detecting means. Be in a state Once detected, and corrects the fuel injection amount injected from said second fuel injection valve based on the intake air amount measured during the exhaust stroke or the intake stroke by the intake air quantity measuring means.

  According to a second aspect of the present invention, there is provided a control device for an internal combustion engine according to the first aspect, wherein the fuel injection control means measures the intake air amount when the acceleration / deceleration state detection means detects that the internal combustion engine is in an acceleration / deceleration state. The fuel injection amount injected from the second fuel injection valve is corrected according to the difference between the intake air amount measured during the expansion stroke and the intake air amount measured during the exhaust stroke or the intake stroke. It is characterized by.

  According to a third aspect of the present invention, there is provided a control device for an internal combustion engine according to the first or second aspect, wherein the fuel injection control means takes in the intake stroke for the fuel injection timing from the second fuel injection valve in accordance with the operating state of the internal combustion engine. The fuel injection is controlled by selecting either the stroke injection or the compression stroke injection in the compression stroke, and when the acceleration / deceleration state detecting means detects that the internal combustion engine is in the acceleration / deceleration state, When the intake stroke injection is selected, the fuel injection amount injected from the second fuel injection valve is corrected based on the intake air amount measured during the exhaust stroke by the intake air amount measuring means, and the compression stroke is corrected. When injection is selected, the fuel injection amount injected from the second fuel injection valve is corrected based on the intake air amount measured during the intake stroke by the intake air amount measuring means. To.

  According to a fourth aspect of the present invention, there is provided a control device for an internal combustion engine according to any one of the first to third aspects, wherein the internal combustion engine has a variable valve timing device that varies an overlap amount of a valve opening period between the intake valve and the exhaust valve, The intake air amount measured during the exhaust stroke or the intake stroke by the intake air amount measuring means is corrected according to the overlap amount variable by the variable valve timing device.

  According to the control apparatus for an internal combustion engine of claim 1, the fuel injection control means supplies fuel from both the first fuel injection valve that injects fuel into the intake passage and the second fuel injection valve that injects fuel directly into the combustion chamber. When injecting, the fuel injection amount to be injected from the first and second fuel injection valves is set based on the intake air amount measured during the expansion stroke by the intake air amount measuring means, and the internal combustion engine is detected by the acceleration / deceleration state detecting means. Is detected in the acceleration / deceleration state, the amount of fuel injected from the second fuel injection valve is corrected based on the amount of intake air measured during the exhaust stroke or the intake stroke by the intake air amount measuring means. I am doing so.

  Therefore, when fuel is injected from both the first fuel injection valve and the second fuel injection valve, the fuel injection amount injected from the first and second fuel injection valves based on the intake air amount measured during the expansion stroke. When the internal combustion engine is in a steady operation state, fuel injection is normally performed by the first and second fuel injection valves based on the fuel injection amount. However, the internal combustion engine is in an acceleration / deceleration state, that is, transient When it is detected that the engine is in the operating state, the fuel injection amount injected from the second fuel injection valve is corrected based on the intake air amount measured during the exhaust stroke or the intake stroke, and from the second fuel injection valve, Fuel injection is performed based on the corrected fuel injection amount.

  Thus, when it is detected that the internal combustion engine is in an acceleration / deceleration state, that is, in a transient operation state, the intake air amount is reduced between the fuel injection by the first fuel injection valve and the fuel injection by the second fuel injection valve. However, the fuel injection from the first fuel injection valve is corrected by correcting the fuel injection from the second fuel injection valve only when such an internal combustion engine is in a transient operation state. The fuel injection from the second fuel injection valve can be performed appropriately and efficiently, and the air-fuel ratio can be efficiently increased with respect to the target air-fuel ratio regardless of whether the internal combustion engine is in a steady operation state or a transient operation state. Thus, the response state of the internal combustion engine can be maintained in a good state at all times.

According to the control apparatus for an internal combustion engine of claim 2, when the acceleration / deceleration state detection means detects that the internal combustion engine is in the acceleration / deceleration state, the fuel injection control means detects the intake air amount measurement means during the expansion stroke. The fuel injection amount injected from the second fuel injection valve is corrected in accordance with the difference between the intake air amount measured during the exhaust stroke and the intake stroke measured during the exhaust stroke or the intake stroke.
This makes it possible to easily and appropriately set the fuel injection amount to be injected from the second fuel injection valve in accordance with the change in the intake air amount, and to improve the efficiency regardless of whether the internal combustion engine is in a steady operation state or a transient operation state. Well, the operating state of the internal combustion engine can always be maintained in a good state.

  According to the control device for an internal combustion engine of claim 3, when the acceleration / deceleration state detecting means detects that the internal combustion engine is in the acceleration / deceleration state, when the intake stroke injection is selected for the second fuel injection valve, When the amount of fuel injected from the second fuel injection valve is corrected based on the amount of intake air measured during the exhaust stroke by the intake air amount measuring means, and the compression stroke injection is selected for the second fuel injection valve The fuel injection amount injected from the second fuel injection valve is corrected based on the intake air amount measured during the intake stroke by the intake air amount measuring means.

  Therefore, when the intake stroke injection is selected for the second fuel injection valve, the fuel injection amount to be injected from the second fuel injection valve is set based on the intake air amount measured during the exhaust stroke before the first stroke. When the compression stroke injection is selected for the second fuel injection valve, the fuel injection amount to be injected from the second fuel injection valve is set based on the intake air amount measured during the intake stroke before the first stroke. .

As a result, the intake air amount measured during the previous stroke is the same regardless of whether the intake stroke injection is selected for the second fuel injection valve or the compression stroke injection is selected. Based on this, the fuel injection amount injected from the second fuel injection valve can be corrected, and the fuel injection amount injected from the second fuel injection valve can be set appropriately.
According to the control device for an internal combustion engine of claim 4, the internal combustion engine has a variable valve timing device that varies an overlap amount during a valve opening period of the intake valve and the exhaust valve, and the exhaust stroke or The intake air amount measured during the intake stroke is corrected according to the overlap amount that is variable by the variable valve timing device.

  Therefore, if the overlap amount of the valve opening period between the intake valve and the exhaust valve is varied by the variable valve timing device, the intake air amount changes. However, the intake air amount measuring means determines the exhaust stroke or the intake stroke. By correcting the intake air amount measured in between according to the overlap amount, the fuel injection amount can be corrected based on the actual intake air amount, and the fuel injection from the second fuel injection valve is more appropriate. Can be implemented.

1 is an overall configuration diagram showing a control device for an internal combustion engine according to the present invention. It is a fuel-injection mode selection map. 3 is a time chart schematically showing a fuel injection timing and an intake air amount measurement period. It is a map which shows the relationship between engine rotational speed Ne, overlap amount, and a correction coefficient.

Hereinafter, an embodiment of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram showing an internal combustion engine control apparatus according to the present invention.
The control apparatus for an internal combustion engine according to the present invention is mounted on a vehicle, and the engine (internal combustion engine) 1 can change a valve mechanism as shown in the figure, and includes intake pipe injection and in-cylinder injection. And a multi-cylinder engine capable of performing both of the above.

  The valve mechanism is a double overhead cam (DOHC) four-valve type valve mechanism, and timing pulleys 4a and 4b are connected to the front ends of the intake cam shaft 3a and the exhaust cam shaft 3b on the cylinder head 2, respectively. The pulleys 4 a and 4 b are connected to the crankshaft 6 through the timing belt 5. Thus, when the engine 1 is operated, the camshafts 3a and 3b are rotationally driven together with the timing pulleys 4a and 4b as the crankshaft 6 is rotated, and the intake valves 7a and Each exhaust valve 7b is driven to open and close.

  A vane type variable timing mechanism (variable valve timing device) 8 is provided between the intake camshaft 3a and the intake side timing pulley 4a. The vane-type variable timing mechanism 8 is publicly known and will not be described in detail. However, a vane rotor is rotatably provided in a housing provided in the timing pulley 4a, and an intake camshaft 3a is connected to the vane rotor. Configured. An oil control valve (OCV) 9 is connected to the timing variable mechanism 8, and the OCV 9 is switched using hydraulic oil supplied from an oil pump (abbreviated as O / P in the figure) 10 of the engine 1, and the OCV 9 is switched. Accordingly, by applying hydraulic pressure to the vane rotor, the phase of the intake camshaft 3a with respect to the timing pulley 4a, that is, the opening / closing timing of the intake valve 7a can be adjusted.

  Further, a vane type timing variable mechanism (variable valve timing device) 41 similar to the intake side is provided between the exhaust camshaft 3b and the exhaust side timing pulley 4b. The vane-type timing variable mechanism 41 is also well-known and will not be described in detail. However, a vane rotor is rotatably provided in a housing provided in the timing pulley 4b, and the intake camshaft 3b is connected to the vane rotor. Configured. An oil control valve (OCV) 42 is connected to the timing variable mechanism 41, and the OCV 42 is switched using hydraulic oil supplied from the oil pump 10 of the engine 1, and hydraulic pressure is applied to the vane rotor according to the switching of the OCV 42. Thus, the phase of the exhaust camshaft 3b with respect to the timing pulley 4b, that is, the opening / closing timing of the exhaust valve 7b can be adjusted.

Specifically, by adjusting the opening / closing timing of the intake valve 7a and the exhaust valve 7b by the timing variable mechanism 8 and the timing variable mechanism 41, the overlap amount of the valve opening period of the intake valve 7a and the exhaust valve 7b can be varied. Is possible.
An intake passage 12 is connected to the intake port 11 of the cylinder head 2, and an air cleaner 13, a throttle valve 14, and a fuel injection valve (first fuel injection valve) 15 are sequentially provided in the intake passage 12 from the intake upstream side. Is provided. Thus, when the engine 1 is in the intake stroke, air is introduced from the air cleaner 13 into the intake passage 12 as the piston 16 is lowered when the intake valve 7a is opened. After the flow rate is adjusted according to the opening of the throttle valve 14, the fuel is mixed with fuel injected from the fuel injection valve 15 (intake pipe injection), and flows into the cylinder through the intake port 11.

In addition, the cylinder head 2 is provided with a spark plug 19 that faces the inside of the cylinder and performs ignition. As a result, it is possible to ignite the air-fuel mixture of the intake air and the fuel flowing into the cylinder as described above, thereby causing homogeneous combustion.
Further, the cylinder head 2 is provided with a fuel injection valve (second fuel injection valve) 20 that faces the cylinder and directly injects fuel into the cylinder. The fuel injection valve 20 is configured to be able to inject fuel (in-cylinder compression stroke injection) toward a cavity 16a formed on the top surface of the piston 16 when the piston 16 is in a predetermined position range, for example. As a result, when the engine 1 is in a compression stroke, for example, fuel is collected in the vicinity of the spark plug 19 while generating a longitudinal vortex (tumble flow) in the combustion chamber formed in the cylinder, so that the fuel injection amount is small. It is possible to cause stratified combustion by igniting with the spark plug 19 even under an air-fuel ratio situation. Further, the fuel injection valve 20 can inject fuel into the combustion chamber (in-cylinder intake stroke injection) even when the engine 1 is in the intake stroke, and can cause homogeneous combustion.

On the other hand, an exhaust passage 18 is connected to the exhaust port 17 of the cylinder head 2. Thereby, when the engine 1 is in the exhaust stroke, the exhaust gas ignited and burned by the spark plug 19 is guided from the exhaust port 17 to the exhaust passage 18 as the piston 16 rises when the exhaust valve 7b is opened, It is discharged to the outside through the catalyst 24 and a silencer (not shown).
An ECU (electronic control unit) including an input / output device (not shown), a storage device (ROM, RAM, etc.) used for storing control programs and control maps, a central processing unit (CPU), a timer counter, etc. ) (Fuel injection control means) 31 is installed and performs overall control of the engine 1. On the input side of the ECU 31, there are a rotation speed sensor 32 for detecting the engine rotation speed Ne, a throttle position (TPS) that is the opening of the throttle valve 14, and a throttle sensor (acceleration / deceleration state detection means) 33 for detecting the engine load. Various sensors such as a water temperature sensor 34 for detecting the water temperature Tw and an air flow sensor (intake air amount measuring means) 35 for detecting the intake air amount are connected. The OCVs 9 and 42, the fuel injection valves 15 and 20, the spark plug 19 and the like are connected to the output side of the ECU 31.

  Thus, the ECU 31 calculates the target phase angle of the timing variable mechanism 8 and the timing variable mechanism 41 from the engine rotation speed Ne and TPS (engine load) according to a preset map, and drives the OCV 9 and OCV 42 to actually The timing variable mechanism 8 and the timing variable mechanism 41 are controlled so that the phase angle becomes the target phase angle. Note that when the engine 1 is cold-started such that the coolant temperature Tw is low, the timing variable mechanism 8 and the timing variable mechanism 41 are controlled to have a phase angle different from that at the time of warm-start in order to suppress discharge of unburned HC. Is done. Further, based on detection information from each sensor, the fuel injection timing, the fuel injection amount, and the ignition timing are determined, and the fuel injection valve 15, the fuel injection valve 20, and the spark plug 19 are driven and controlled.

Hereinafter, the control of the control apparatus for an internal combustion engine according to the present invention configured as described above, that is, the contents of fuel injection control will be described in detail.
As described above, in the control device for an internal combustion engine according to the present invention, the engine 1 has the two fuel injection valves of the fuel injection valve 15 and the fuel injection valve 20, and the fuel injection is performed according to the operating state of the engine 1. The fuel injection from the valve 15 and the fuel injection from the fuel injection valve 20 are selectively used.

  Referring to Table 1, the table shows seven fuel injection modes that can be implemented in the control device for an internal combustion engine according to the present invention.

  As shown in the table, in the control apparatus for an internal combustion engine according to the present invention, mode 1: single intake pipe injection, mode 2: single cylinder intake stroke injection, mode 3: single cylinder compression stroke injection, mode 4: normal Intake pipe injection and in-cylinder intake stroke injection, mode 5: normal intake pipe injection and in-cylinder compression stroke injection, mode 6: intake pipe injection and in-cylinder intake stroke injection during acceleration / deceleration, mode 7: during acceleration / deceleration Intake pipe injection and in-cylinder compression stroke injection can be appropriately performed.

In the control apparatus for an internal combustion engine according to the present invention, these fuel injection modes are selected according to the operating state of the engine 1. Specifically, the operating state of the engine 1 includes, for example, a normal operating state, a catalyst temperature increasing operation state (cold start operating state), a special operating state, and a lean operating state, and the fuel injection mode according to these operating states. Is appropriately selected.
Referring to FIG. 2, each of (a) normal operation state, (b) catalyst temperature rising operation state, (c) special operation state, and (d) lean operation state is preset according to the engine speed Ne and the engine load. Each of the fuel injection mode selection maps is shown, and the fuel injection mode corresponding to the operating state of the engine 1 is appropriately selected according to these maps.

  Specifically, (a) in the normal operation state, mode 1 single intake pipe injection is selected in a region where both the engine speed Ne and the engine load are low, and mode 4 is selected in a region where both are high. Normal intake pipe injection and in-cylinder intake stroke injection are selected. (B) In the catalyst temperature rising operation state, the mode 4 normal intake pipe injection and in-cylinder intake stroke injection are selected in a region where both the engine speed Ne and the engine load are low, and in both regions where both are high. Mode 5 normal intake pipe injection and in-cylinder compression stroke injection are selected. (C) When the vehicle is in a special operation state (for example, when the vehicle is stopped, sudden acceleration starts from a low speed, or when climbing up a steep slope), the mode 1 alone is used in a region where both the engine speed Ne and the engine load are low. In the region where the intake pipe injection is selected and the engine speed Ne is low and the engine load is high, the mode 2 single cylinder intake stroke injection is selected. In the area where both are high, the mode 4 normal intake pipe injection and cylinder intake are selected. Select stroke injection. (D) In the lean operation state, the mode 3 single cylinder compression stroke injection is selected in the region where both the engine speed Ne and the engine load are low, and the mode 4 normal intake is performed in the region where both are high. Pipe injection and in-cylinder intake stroke injection are selected.

  Even in the driving states shown in the above (a) to (d), the opening degree of the throttle valve 14 is greatly changed with a predetermined change degree, and the vehicle suddenly accelerates or decelerates. When it is determined that the engine 1 is in the acceleration / deceleration state based on the information from the above, when (a) the normal operation state, (b) the catalyst temperature increase operation state, and (c) the special operation state, 6 is selected for the intake pipe injection and the in-cylinder intake stroke injection during acceleration / deceleration. (D) In the lean operation state, the intake pipe injection and the in-cylinder compression stroke injection during acceleration / deceleration in mode 7 are selected. .

Hereinafter, the fuel injection modes from Mode 1 to Mode 7 will be described in detail.
In the case of fuel injection, first, a target air-fuel ratio (target A / F) is set based on the engine rotational speed Ne and the engine load, and the target A / F and the intake air amount detected by the air flow sensor 35 are set. Based on this, the total fuel injection amount is set.
When the total fuel injection amount is set, the fuel amounts to be injected from the fuel injection valve 15 and the fuel injection valve 20 are respectively determined according to the above-described modes 1 to 7. Specifically, in each map of FIG. 2 described above, reference injection ratios of fuel amounts injected from the fuel injection valve 15 and the fuel injection valve 20 are set in advance according to the engine speed Ne and the engine load. The amount of fuel injected from the fuel injection valve 15 and the fuel injection valve 20 is set in accordance with the reference injection ratio.

  Referring to FIG. 3, the fuel injection timings of the fuel injection valve 15 and the fuel injection valve 20 and the intake air amount measurement period by the air flow sensor 35 are schematically shown in a time chart. Further, referring to Table 2, the intake air amount measurement periods corresponding to the above-described modes 1 to 7 are indicated by circles, and the intake air amount is measured according to the modes 1 to 7 based on the table. A period is selected.

As shown in FIG. 3, the intake air amount measurement period includes a measurement period A in the expansion stroke, a measurement period B in the exhaust stroke, and a measurement period C in the intake stroke.
As shown in Table 2, in the single intake pipe injection in mode 1, the intake pipe fuel injection amount is set based on the intake air amount measured in the measurement period A, and in the single cylinder intake stroke injection in mode 2, The in-cylinder fuel injection amount is set based on the intake air amount measured in the measurement period B. In the single in-cylinder compression stroke injection in mode 3, the in-cylinder fuel injection amount is set based on the intake air amount measured in the measurement period C. Is set. That is, for the single intake pipe injection in mode 1, the single in-cylinder intake stroke injection in mode 2, and the single in-cylinder compression stroke injection in mode 3, the fuel injection amount is based on the intake air amount measured in the period one step before. Is set.

  In the normal intake pipe injection and in-cylinder intake stroke injection in mode 4, and in the normal intake pipe injection and in-cylinder compression stroke injection in mode 5, the entire fuel is calculated based on the intake air amount measured in the measurement period A. An injection amount is set, and the fuel injection amount is distributed to the intake pipe fuel injection amount and the in-cylinder fuel injection amount according to the reference injection ratio of the fuel amount injected from the fuel injection valve 15 and the fuel injection valve 20. That is, when normal intake pipe injection and in-cylinder intake stroke injection in mode 4 and normal intake pipe injection and in-cylinder compression stroke injection in mode 5 are selected, in-cylinder intake stroke injection and in-cylinder compression stroke injection are selected. Even if there is, the intake pipe fuel injection amount and the in-cylinder fuel injection amount are set based only on the intake air amount measured in the measurement period A in the expansion stroke.

  In other words, when both the intake pipe injection and the in-cylinder injection are performed, the intake air amount is in the measurement period B even in the measurement period A when the engine 1 is normally operated without acceleration / deceleration. Can be regarded as equivalent even during the measurement period C, and not only the intake pipe fuel injection quantity but also the in-cylinder fuel injection quantity is set based on the intake air quantity measured during the measurement period A. Thus, when normal intake pipe injection and in-cylinder intake stroke injection in mode 4 and normal intake pipe injection and in-cylinder compression stroke injection in mode 5 are selected, in-cylinder intake stroke injection and in-cylinder compression stroke are performed. The in-cylinder fuel injection amount in the injection can be determined at an early stage, and fuel injection control can be performed efficiently without waste.

  In intake pipe injection and in-cylinder intake stroke injection during acceleration / deceleration in mode 6, the entire fuel injection amount is set based on the intake air amount measured in the measurement period A, and the fuel injection amount is set according to the reference injection ratio. Is distributed between the intake pipe fuel injection amount and the in-cylinder fuel injection amount. For the in-cylinder intake stroke injection, the in-cylinder fuel injection amount is corrected and set based on the intake air amount measured in the measurement period B. Similarly, in the intake pipe injection and the in-cylinder compression stroke injection during acceleration / deceleration in mode 7, the entire fuel injection amount is set based on the intake air amount measured in the measurement period A, and according to the reference injection ratio. The fuel injection amount is distributed between the intake pipe fuel injection amount and the in-cylinder fuel injection amount. For the in-cylinder compression stroke injection, the in-cylinder fuel injection amount is corrected and set based on the intake air amount measured in the measurement period C. Is done.

  Specifically, in mode 6, after obtaining the intake pipe fuel injection amount and the in-cylinder fuel injection amount based on the intake air amount measured in the measurement period A, the intake air amount measured in the measurement period A and the measurement period A difference from the intake air amount measured in B is calculated, a fuel injection increase / decrease amount is calculated based on the difference, and this fuel injection increase / decrease amount is added to the in-cylinder fuel injection amount to thereby determine the cylinder in the cylinder intake stroke injection. Set the internal fuel injection amount. Similarly, in mode 7, after obtaining the intake pipe fuel injection amount and the in-cylinder fuel injection amount based on the intake air amount measured in the measurement period A, the intake air amount measured in the measurement period A and the measurement period C are calculated. In-cylinder fuel in in-cylinder compression stroke injection is obtained by calculating a difference from the measured intake air amount, calculating a fuel injection increase / decrease amount based on this difference, and adding this fuel injection increase / decrease amount to the in-cylinder fuel injection amount. Set the injection amount.

  That is, during the acceleration / deceleration of the engine 1, that is, during the transient operation of the engine 1, the intake pipe fuel injection amount and the in-cylinder fuel injection amount based on the intake air amount measured in the measurement period A in the expansion stroke as in the normal case. Thereafter, the in-cylinder fuel injection amount is further corrected and set based on the intake air amount measured in the measurement period B and the measurement period C one step before the in-cylinder intake stroke injection and the in-cylinder compression stroke injection, respectively. I am doing so.

As a result, even when the engine rotational speed Ne changes suddenly during the transient operation of the engine 1 and the intake air amount changes with time, the fuel injection valve 15 and the fuel injection valve 20 respectively. An appropriate amount of fuel can be injected without excess or deficiency.
As described above, according to the control apparatus for an internal combustion engine according to the present invention, when the engine 1 is in the steady operation state, not only the intake pipe fuel injection amount but also the cylinder based on the intake air amount measured in the measurement period A. Only when the internal fuel injection amount is set and the engine 1 is in a transient operation state, the intake measured in the measurement period B and the measurement period C one step before the in-cylinder intake stroke injection and the in-cylinder compression stroke injection, respectively. The in-cylinder fuel injection amount is corrected and set based on the air amount.

Therefore, the fuel injection from the fuel injection valve 15 and the fuel injection from the fuel injection valve 20 can be performed appropriately and efficiently, and the engine 1 is in a transient operation state even when it is in a steady operation state. Even so, it is possible to efficiently prevent the response delay of the air-fuel ratio from occurring with respect to the target A / F, and the operating state of the engine 1 can always be maintained in a good state.
The engine 1 can adjust the opening / closing timing of the intake valve 7a and the exhaust valve 7b by the timing variable mechanism 8 and the timing variable mechanism 41 to vary the overlap amount of the valve opening period of the intake valve 7a and the exhaust valve 7b. Since the intake air amount into the cylinder also changes according to the overlap amount, the intake air amounts in the measurement period B and the measurement period C are corrected according to the overlap amount.

  Specifically, referring to FIG. 4, the relationship among the engine speed Ne, the overlap amount, and the correction coefficient during acceleration (a) and deceleration (b) is set in advance and shown as a map. A correction coefficient is read from the same figure in accordance with Ne and the overlap amount, and each intake air amount in the measurement period B and measurement period C is calculated by multiplying the correction coefficient.

  As a result, particularly when the engine 1 is in a transient operation state and the intake air amount changes greatly, if the intake air amount measured by the air flow sensor 35 provided in the intake passage 12 is directly used for calculation, an error in the fuel injection amount occurs. However, it is possible to set the in-cylinder fuel injection amount based on an appropriate intake air amount that is realistic and to inject a more appropriate amount of fuel from the fuel injection valve 20. Can do.

The description of the embodiment is finished as above, but the aspect of the present invention is not limited to the above embodiment.
For example, in each of the above embodiments, the intake air amount in the measurement period B and the measurement period C is corrected according to the overlap amount in the valve opening period of the intake valve 7a and the exhaust valve 7b. If it is not so large, this correction need not be performed.

1 engine (internal combustion engine)
7a Intake valve 7b Exhaust valve 8, 41 Timing variable mechanism (variable valve timing device)
12 Intake passage 15 Fuel injection valve (first fuel injection valve)
20 Fuel injection valve (second fuel injection valve)
31 ECU (electronic control unit) (fuel injection control means)
32 Rotational speed sensor 33 Throttle sensor (acceleration / deceleration state detection means)
35 Air flow sensor (Measurement of intake air volume)

Claims (4)

A first fuel injection valve for injecting fuel into an intake passage of the internal combustion engine;
A second fuel injection valve that directly injects fuel into the combustion chamber of the internal combustion engine;
An intake air amount measuring means for measuring an intake air amount into the combustion chamber;
Fuel injection control means for controlling the fuel injection injected from the first and second fuel injection valves in accordance with the operating state of the internal combustion engine;
Acceleration / deceleration state detection means for detecting that the internal combustion engine is in an acceleration / deceleration state,
When the fuel injection control means injects fuel from both the first and second fuel injection valves, the first and second fuel injection control means are based on the intake air amount measured during the expansion stroke by the intake air amount measurement means. When the fuel injection amount to be injected from the second fuel injection valve is set and the acceleration / deceleration state detecting means detects that the internal combustion engine is in the acceleration / deceleration state, the intake air amount measuring means detects the exhaust stroke or the intake stroke. A control apparatus for an internal combustion engine, wherein a fuel injection amount injected from the second fuel injection valve is corrected based on an intake air amount measured in between. The fuel injection control means includes
When the acceleration / deceleration state detection means detects that the internal combustion engine is in an acceleration / deceleration state, the intake air amount measurement means measures between the intake air amount measured during the expansion stroke and the exhaust stroke or the intake stroke. 2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection amount injected from the second fuel injection valve is corrected in accordance with a difference from the intake air amount that is performed. The fuel injection control means includes
The fuel injection is controlled by selecting either the intake stroke injection in the intake stroke or the compression stroke injection in the compression stroke for the fuel injection timing from the second fuel injection valve according to the operating state of the internal combustion engine. And
When it is detected by the acceleration / deceleration state detection means that the internal combustion engine is in an acceleration / deceleration state,
When the intake stroke injection is selected, the fuel injection amount injected from the second fuel injection valve is corrected based on the intake air amount measured during the exhaust stroke by the intake air amount measuring means;
When the compression stroke injection is selected, the fuel injection amount injected from the second fuel injection valve is corrected based on the intake air amount measured during the intake stroke by the intake air amount measuring means. The control device for an internal combustion engine according to claim 1 or 2. The internal combustion engine has a variable valve timing device that varies the amount of overlap between the intake valve and the exhaust valve during the valve opening period,
The intake air amount measured during the exhaust stroke or the intake stroke by the intake air amount measuring means is corrected according to the overlap amount that is variable by the variable valve timing device. The control apparatus of the internal combustion engine in any one of these.

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