JP5169653B2 - Control method and apparatus for spark ignition direct injection engine - Google Patents

Description

The present invention relates to a control method and apparatus for a spark ignition direct injection engine.

Engines, particularly spark ignition engines for automobiles, have a strong tendency to use direct injection in which fuel is directly injected into the combustion chamber from the viewpoint of a high degree of freedom in fuel injection timing selection and improved efficiency. In addition, gasoline is generally used as a fuel for a spark ignition direct injection engine, but recently, a mixed fuel in which ethanol is mixed with gasoline and a fuel in which ethanol is 100% are often used. . For example, E10 (contains 10% ethanol and the remaining 90% is gasoline), E25 (contains 25% ethanol), E85 (combined fuel in which ethanol is mixed with gasoline), depending on the content ratio of ethanol in the fuel. (Contains 85% ethanol).

In Patent Document 1, when a plurality of types of fuels having different octane numbers, for example, gasoline, ethanol, and a mixed fuel of ethanol and gasoline are selectively used, a mirror having a low octane number is used at low load. A cycle is disclosed in which combustion is performed at a high compression ratio while using a high-octane fuel at high loads.

In Patent Document 2, in order to prevent knocking in a high load region of the engine, a predetermined period in which the intake valve is closed after the exhaust valve is closed near the intake top dead center is set. A negative overlap is disclosed in which an intake valve is opened during an intake stroke after a predetermined period has elapsed.
JP 2008-031948 A JP 2002-213259 A

By the way, when using a mixed fuel of gasoline and ethanol, the content ratio of ethanol in the fuel may be significantly changed. That is, the ethanol content may vary over a wide range from 0% (ie, gasoline 100%) to 100% (ie, ethanol 100%).

On the other hand, there is a large difference in fuel vaporization characteristics between gasoline and ethanol, and fuel with a high ethanol or ethanol content ratio (especially with an ethanol content ratio of 10% or more) reduces the fuel component that tends to vaporize and fuel. The vaporization characteristics of the engine are considerably poorer than those of gasoline, and therefore, the combustion stability is low when the engine is cold or in a low speed region, particularly in a low speed / low load region.

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a spark ignition type direct current engine that can sufficiently ensure combustion stability in the low speed region of the engine regardless of the ethanol content. An object of the present invention is to provide an injection engine control method and apparatus.

In order to achieve the above object, the following first solution is adopted in the control method of the present invention. That is, as described in claim 1 in the claims,
Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control method in which the mixed fuel can be used.
When it is determined that the first fuel in which the content of ethanol in the fuel is 10% or more is used in the low speed region of the engine, the intake valve and the exhaust valve are each closed during the intake stroke. Fuel injection is performed in a period that sets a period and overlaps at least a part of the predetermined period,
When it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used in the low speed region of the engine , the intake valve and the exhaust valve are each closed during the intake stroke. In addition to setting the period, fuel injection is performed during the opening period of the intake valve in the intake stroke.
It is like that.

According to the above-described solution technique, during the predetermined period in which both the intake valve and the exhaust valve are closed, the inside of the cylinder is brought to a very large negative pressure as the intake stroke proceeds. Therefore, by injecting the first fuel having poor fuel vaporization characteristics so as to overlap with a part of the predetermined period, the first fuel is sufficiently evaporated in the cylinder having an extremely large negative pressure. (Sufficient promotion of vaporization and atomization) ensures sufficient combustion stability. Further, when using the second fuel with good fuel vaporization characteristics, the fuel injection is performed during the opening period of the intake valve in the normal intake stroke, avoiding the predetermined period in which a large negative pressure is generated, thereby The situation where the internal pressure is low and the injected fuel jumps too much, and the fuel component that adheres in large amounts to the piston top surface or combustion chamber wall surface and does not vaporize easily causes smoke generation, and opens the intake valve. It is possible to increase the homogeneity of the air-fuel mixture by utilizing the intake air flow at the time, and sufficiently ensure the combustion stability.
In addition to the above, since a large negative pressure is generated in the cylinder when the intake valve is closed in the intake stroke, a large intake flow using the large negative pressure in the cylinder is utilized when the intake valve is opened. Can be obtained, and the combustion stability can be further improved. Regardless of the content ratio of ethanol, it is possible to set the valve timing to uniformly set a predetermined period in the low speed region of the engine, which is also preferable in preventing the valve timing from being changed frequently.

In order to achieve the above object, the following second solution is adopted in the control method of the present invention. That is, as described in claim 2 in the scope of claims,
Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control method in which the mixed fuel can be used.
In the low speed / high load region of the engine, the exhaust valve is closed after the intake top dead center, and the intake valve is opened during the intake stroke delayed for a predetermined period after the exhaust valve is closed,
When it is determined that the first fuel in which the content of ethanol in the fuel is 10% or more is used in the low speed / high load region of the engine, it is in a period overlapping with at least a part of the predetermined period. On the other hand, when it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used, the fuel injection is performed during the intake valve opening period in the intake stroke. And
The fuel injection in a period overlapping with at least a part of the predetermined period of the first fuel is a batch injection,
The fuel injection in the opening period of the intake valve in the intake stroke of the second fuel is divided injection in the intake stroke, or divided injection in the intake stroke and the compression stroke.
It is like that. According to the second solution described above, regardless of the ethanol content ratio, the intake valve is closed late by setting a predetermined period in which both the intake valve and the exhaust valve are closed in the intake stroke. As a result, the in-cylinder temperature decreases and knocking can be suppressed by shortening the combustion time using the large intake flow after the intake valve is opened. Therefore, when the second fuel, which is likely to cause knocking, is used, the effect of accelerating the intake air flow can be obtained by injecting fuel during the intake valve opening period in the intake stroke. Combustion stability is ensured and knocking can be reliably prevented. Also, when using the first fuel with poor fuel vaporization characteristics, the fuel is injected in a period that overlaps at least a part of the predetermined period, and vaporization and fog are generated using a large negative pressure in the cylinder. Acceleration can be promoted to ensure stable combustion.

In addition to the above, a bad first fuel vaporization characteristics of the fuel is by a batch injection, once its vaporization and to promote atomization, be preferred over the combustion stability ensured, also short predetermined period of time It becomes possible to inject a relatively large amount of fuel corresponding to the above. In addition, the second fuel with good fuel vaporization characteristics uses split injection of a relatively large amount of fuel to homogenize the air-fuel mixture and a part of the fuel to the piston top surface and combustion chamber wall surface. It is preferable in terms of prevention of knocking and ensuring of combustion stability by satisfying both prevention of adhesion.

In order to achieve the above object, the following first solution is adopted in the control device of the present invention. That is, as described in claim 3 in the claims,
Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control device in which the mixed fuel can be used,
Valve timing adjusting means for setting a predetermined period during which the intake valve and the exhaust valve are closed in the intake stroke;
When it is determined that the first fuel in which the ethanol content in the fuel is 10% or more is used in the low speed region of the engine, the valve timing adjusting means is controlled to set the predetermined period. First fuel injection control means for performing fuel injection during a period overlapping with at least a part of the predetermined period;
When it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used in the low speed region of the engine, the valve timing adjusting means is controlled to set the predetermined period. And a second fuel injection control means for performing fuel injection during the valve opening period of the intake valve in the intake stroke;
It is supposed to be equipped with. According to the said solution technique, the control apparatus for performing the control method of Claim 1 is provided.

In order to achieve the above object, the following second solution is adopted in the control apparatus of the present invention. That is, as described in claim 4 in the claims,
Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control device in which the mixed fuel can be used,
Valve timing adjusting means for opening the intake valve during the intake stroke delayed for a predetermined period after the exhaust valve is closed after the intake top dead center;
When it is determined that the first fuel in which the ethanol content in the fuel is 10% or more is used in the low speed / high load region of the engine, the valve timing adjusting means is controlled to control the predetermined period. A first fuel injection control means for performing fuel injection during a period overlapping with at least a part of the predetermined period;
When it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used in the low-speed / high-load region of the engine, the fuel is consumed during the intake valve opening period in the intake stroke. Second fuel injection control means for performing injection;
Bei to give a,
The fuel injection in a period overlapping with at least a part of the predetermined period of the first fuel is a batch injection,
The fuel injection in the opening period of the intake valve in the intake stroke of the second fuel is divided injection in the intake stroke, or divided injection in the intake stroke and the compression stroke.
It is like that. According to the above solution, a control device for executing the control method according to claim 2 is provided.

According to the present invention, combustion stability in the engine low speed region can be ensured regardless of the content ratio of ethanol.

In FIG. 1, E is an engine, particularly an automobile engine. In the embodiment, E is an in-line four-cylinder engine. In FIG. 1, one cylinder is representatively shown, and a combustion chamber 4 is defined by a cylinder 1, a cylinder head 2, and a piston 3 slidably fitted in the cylinder 1. A fuel injection valve 5 and a spark plug 6 are disposed facing the combustion chamber 4.

In the combustion chamber 4, two intake ports 10 and two exhaust ports 11 formed in the cylinder head 2 are opened. In FIG. 1, one of the two intake ports 10 and the two exhaust ports 11 is disposed in a direction perpendicular to the paper surface and is not depicted in FIG. 1. The intake port 10 is opened and closed by an intake valve 12, and the exhaust port 11 is opened and closed by an exhaust valve 13. A camshaft for driving the intake valve 12 to open and close is indicated by reference numeral 14, and a camshaft for driving the exhaust valve 13 to open and close is indicated by reference numeral 15. Each of the camshafts 14 and 15 is interlocked with a crankshaft (that is, the piston 3) (not shown). A phase adjustment mechanism 16 is incorporated in the interlocking mechanism between the crankshaft and the camshaft 14 for the intake valve 12. The phase adjusting mechanism 16 changes the rotational position of the camshaft 14 relative to the rotational position of the crankshaft, and has a function of offsetting the opening / closing timing of the intake valve 12 as will be described later. Such a phase adjustment mechanism 16 is hydraulic or electromagnetic, and various types have been proposed and well known in the art, and detailed description thereof will be omitted.

The intake port 10 in each cylinder is connected to a surge tank 21 via a branch intake passage 20. A common intake passage 22 is connected to the surge tank 21. An air cleaner 23 is disposed at the upstream end of the common intake passage 22, and a throttle valve 24 is disposed downstream of the air cleaner 23. On the other hand, the exhaust gas from the exhaust port 11 is discharged to the atmosphere through the exhaust passage 30. An exhaust gas purification device 31 such as a three-way catalyst is disposed in the exhaust passage 30. An air-fuel ratio sensor S3 is disposed in the exhaust passage 30 upstream of the exhaust gas purification device 31. The air-fuel ratio sensor S3 may be one that turns on and off at the theoretical air-fuel ratio, and may be one that can detect the air-fuel ratio continuously.

In FIG. 2, U is a controller (control unit) configured using a microcomputer. The controller U controls the fuel injection valve 5, the spark plug 6, and the phase adjustment mechanism 16 described above. Signals from various sensors S1 to S5 are input to the controller U. The sensor S1 detects an engine load. In the embodiment, the sensor S1 detects an intake air amount. The sensor S2 detects the engine speed. Sensor S3 is the air-fuel ratio sensor described above. The sensor S4 detects the rotational position of the crankshaft, that is, the crank angle.

An outline of the control of the controller U will be described with reference to FIGS. First, FIG. 3 shows a map for controlling the phase adjustment mechanism 16. In FIG. 3, the engine speed and the engine load are used as parameters, and the area is divided into two regions X1 and X2. In FIG. 3, WOT indicates the total load. The region X1 is set as a region other than the high load region of the entire low rotation region and the middle / high rotation region. The region X2 is set as a region other than the region X1 (the region X2 is a region excluding the low rotation region in the high load region). In addition, the low rotation side boundary line of the region X2 is indicated by the α line, the load boundary line is indicated by the β line, and the region that rotates at a higher speed than the α line and has a higher load than the β line is defined as the region X2. ing. In the embodiment, the α line is set to the rotation speed N1 (linear), and the β line is a constant load R1 in the low rotation range up to N1, but in the range of the rotation speed N1 or more, the rotation speed increases. It is set nonlinearly so that the load is gradually increased.

In the region X2, the intake valve 12 and the exhaust valve 13 are set to normal opening / closing timing. That is, as shown in FIG. 4, the exhaust valve 13 is closed after the intake top dead center, the intake valve 12 is opened before the intake top dead center, the intake valve 12, the exhaust valve 13, Are made to have an overlap opened together. The fuel injection is performed while the intake valve 12 is open.

On the other hand, in the region X1, as shown in FIG. 5 or FIG. 6, the valve opening timing of the intake valve 12 is opened at a timing that is considerably later than the intake top dead center, that is, a timing that is later than the valve closing timing of the exhaust valve 13. Thus, a predetermined period T that is the time when both the intake valve 12 and the exhaust valve 13 are closed is set. An open / close state in which the intake valve 12 and the exhaust valve 13 are both closed for a predetermined period T is referred to as a negative overlap. The closing timing of the intake valve 12 is set so as to be in the middle of the compression stroke that is considerably later than the intake bottom dead center. In other words, the intake valve 12 is offset in the direction in which the valve opening period is retarded as a whole by the phase adjusting mechanism 16, and the intake valve is closed late, which also serves as a valve timing for reducing the pumping loss.

The fuel injection timing in the region X1 where the negative overlap is set is set as follows. First, in the low load region (region where the load is lower than the β-ray in FIG. 3 and the region extends from the low speed to the high speed range), the first fuel (ethanol) in which the mixing ratio of ethanol in the fuel is 10% or more. (Including the case of 100%), fuel injection is performed at a timing overlapping with at least a part of the predetermined period T as shown in FIG. In the predetermined period T, an extremely large negative pressure is generated in the cylinder as the piston 3 moves toward the intake bottom dead center while the intake valve 12 is closed. Therefore, by injecting the first fuel, which has poor ignitability and fuel vaporization characteristics, into the atmosphere where the large negative pressure is generated, its evaporation is promoted (evaporation and atomization is promoted) and stable. Combustion can be obtained.

On the other hand, when the second fuel in which the mixing ratio of ethanol in the fuel is less than 10% (including the case of gasoline 100%) is used in the low load region, the fuel injection is performed in the intake stroke. The intake valve 12 after the predetermined period T is opened. That is, since a large intake flow is generated in the cylinder when the intake valve 12 is opened by the large negative pressure generated in the cylinder during the predetermined period T, the second excellent in ignitability and fuel vaporization characteristics. The fuel is homogenized by this large intake air flow, and combustion stability is ensured. If the second fuel is injected during the predetermined period T, the fuel will fly too much and will adhere to the top surface of the piston 3 and the inner wall surface of the combustion chamber 4 that are still close to top dead center. This is undesirable in terms of homogenization.

In the region X1, which is negatively overlapped, in the low speed / high load region (the region where the rotation is lower than N1 in FIG. 3 and the load is higher than R1), fuel injection is performed as follows. First, when the first fuel having poor ignitability and fuel vaporization characteristics is used, fuel injection is executed so as to overlap with at least a part of the predetermined period T as shown in FIG. (Batch injection). In the low-speed / high-load region, knocking generally tends to be a problem, but knocking does not become a problem when using the first fuel with poor ignitability and fuel vaporization characteristics. The fuel injection promotes the evaporation of fuel using a large negative pressure in the cylinder, and ensures combustion stability.

In the low speed / high load region, when using the second fuel, which has good ignitability and fuel vaporization characteristics and is likely to cause knocking problems, as shown in FIG. Divided injection. That is, in the embodiment, the pre-stage injection is executed in a period during which the intake valve 12 is open in the intake stroke, and the post-stage injection is executed in the compression stroke (late stage). By adopting such split injection, in the pre-stage injection, the air-fuel mixture is homogeneous due to a large intake flow when the intake valve 12 is opened (a large negative pressure is generated in the cylinder in a predetermined period T in advance). Therefore, a situation in which a locally rich portion is formed in the cylinder is prevented, and the temperature in the cylinder also decreases during the predetermined period T, so that knocking can be prevented. Further, by performing the post-stage injection, the necessary fuel amount as a whole is ensured while reducing the injection quantity of the pre-stage injection. The ignition is performed after the compression top dead center, but can be performed before the compression top dead center as long as knocking can be prevented. Further, the divided injection may be three or more divided injections, and the divided injection may be performed only during a period in which the intake valve 12 is opened in the intake stroke.

The controller U is adapted to determine the mixing ratio of ethanol in the fuel. That is, in the same operation state (operation state where the engine speed and engine load are the same), the ethanol content increases as the current fuel injection amount increases with respect to the air-fuel ratio detected by the air-fuel ratio sensor S3. It can be judged. That is, the theoretical air-fuel ratio of gasoline is 14.7, whereas the theoretical air-fuel ratio of ethanol is 9, so the difference in the theoretical air-fuel ratio is used to determine the mixing ratio of ethanol in the fuel. can do. When an air-fuel ratio sensor S3 that is turned on and off at the theoretical air-fuel ratio is used, the mixing ratio of ethanol in the fuel is determined when the air-fuel ratio sensor S3 detects the stoichiometric air-fuel ratio. do it.

FIG. 7 is a flowchart showing the above-described control example by the controller U. This flowchart will be described below. In the following description, Q indicates a step. First, in Q1, signals from various sensors S1 to S4 are read. Thereafter, in Q2, it is determined whether or not the current operating state of the engine E is the region X1 shown in FIG. If the determination in Q2 is YES, the phase adjustment mechanism 16 is controlled so that a negative overlap is obtained in Q3. If NO in Q2, the phase adjustment mechanism 16 is controlled so that there is an overlap in Q4.

After Q3 and Q4, based on the air-fuel ratio detected by the air-fuel ratio sensor S3 and the fuel injection amount in Q5, the mixing ratio of ethanol in the fuel is about the currently used fuel. Determined. Thereafter, at Q6, it is determined whether or not the vehicle is in a low speed region (a rotation region equal to or less than N1 in FIG. 3). If the determination in Q6 is YES, it is determined in Q7 whether or not it is a high load region (region of higher load than the β line in FIG. 3). When the determination in Q7 is YES, it is determined whether or not the currently used fuel is the first fuel in which the mixing ratio of ethanol in the fuel is 10% or more. When the determination in Q8 is YES, in Q9, as shown in FIG. 6, fuel injection is performed at a timing that overlaps at least a part of the predetermined period T. When the determination in Q8 is NO, in Q10, as shown in FIG. 6, split injection is performed between the front-stage injection in the intake stroke and the rear-stage injection in the compression stroke.

If the determination in Q7 is NO, it is determined in Q11 whether the currently used fuel is the first fuel in which the mixing ratio of ethanol in the fuel is 10% or more. If YES in Q11, fuel injection is performed in Q12 at a timing that overlaps at least a part of the predetermined period T as shown in FIG. If NO in Q11, fuel injection is performed in Q13 during a period in which the intake valve 12 is open during the intake stroke (second fuel injection mode shown in FIG. 5).

When the determination in Q6 is NO, in Q13, fuel injection is performed during a period in which the intake valve 12 is open in the intake stroke (depending on the load, the case where there is an overlap shown in FIG. There is a case of negative overlap shown in FIG.

Although the embodiment has been described above, the present invention is not limited to the embodiment, and can be appropriately changed within the scope described in the scope of claims. For example, the invention includes the following cases. . Only when the ethanol content is high (for example, 10% or more), the negative overlap may be set and the fuel injection may be performed during the predetermined period T. In order to detect the mixing ratio of ethanol in the fuel, a dedicated sensor for detecting the mixing ratio may be used separately.

The engine E may be of an appropriate type such as a supercharged type, three cylinders, six cylinders or more. Further, the negative overlap may be set by changing the opening / closing timing of the exhaust valve and changing the opening / closing timing of both the intake valve and the exhaust valve. In this way, the degree of freedom of the negative overlap period and size can be expanded, and a negative overlap more suitable for the engine operating state can be set.

Further, in a setting where a negative overlap is detected at the time of deceleration detection, it is preferable to maintain the negative overlap until at least immediately before the fuel return (advance the fuel return when the throttle valve is fully closed in advance). The negative overlap may be set only when the fuel returns from the fully closed throttle valve. Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

The simplified system diagram which shows an example of the engine to which this invention was applied. The block diagram which shows the example of a control system of this invention. The map which shows the example of a change of the overlap state of an intake valve and an exhaust valve. The figure which shows the setting of the overlap in a high speed and high load area | region, and a fuel-injection aspect. The figure which shows the setting of the negative overlap in a low load area | region, and a fuel-injection aspect. The figure which shows the setting of the negative overlap in a low speed and high load area | region, and a fuel-injection aspect. The flowchart which shows the example of control of this invention.

U: Controller E: Engine 4: Combustion chamber 5: Fuel injection valve 6: Spark plug 12: Intake valve 13: Exhaust valve 16: Phase adjustment mechanism S1: Sensor (engine load)
S2: Sensor (engine speed)
S3: Sensor (air-fuel ratio sensor)
S4: Sensor (crank angle)

Claims (4)

Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control method in which the mixed fuel can be used.
When it is determined that the first fuel in which the content of ethanol in the fuel is 10% or more is used in the low speed region of the engine, the intake valve and the exhaust valve are each closed during the intake stroke. Fuel injection is performed in a period that sets a period and overlaps at least a part of the predetermined period,
When it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used in the low speed region of the engine , the intake valve and the exhaust valve are each closed during the intake stroke. In addition to setting the period, fuel injection is performed during the opening period of the intake valve in the intake stroke.
A control method for a spark ignition direct injection engine. Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control method in which the mixed fuel can be used.
In the low speed / high load region of the engine, the exhaust valve is closed after the intake top dead center, and the intake valve is opened during the intake stroke delayed for a predetermined period after the exhaust valve is closed,
When it is determined that the first fuel in which the content of ethanol in the fuel is 10% or more is used in the low speed / high load region of the engine, it is in a period overlapping with at least a part of the predetermined period. On the other hand, when it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used, the fuel injection is performed during the intake valve opening period in the intake stroke. And
The fuel injection in a period overlapping with at least a part of the predetermined period of the first fuel is a batch injection,
The fuel injection in the opening period of the intake valve in the intake stroke of the second fuel is divided injection in the intake stroke, or divided injection in the intake stroke and the compression stroke.
A control method for a spark ignition direct injection engine. Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control device in which the mixed fuel can be used,
Valve timing adjusting means for setting a predetermined period during which the intake valve and the exhaust valve are closed in the intake stroke;
When it is determined that the first fuel in which the ethanol content in the fuel is 10% or more is used in the low speed region of the engine, the valve timing adjusting means is controlled to set the predetermined period. First fuel injection control means for performing fuel injection during a period overlapping with at least a part of the predetermined period;
When it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used in the low speed region of the engine, the valve timing adjusting means is controlled to set the predetermined period. And a second fuel injection control means for performing fuel injection during the valve opening period of the intake valve in the intake stroke;
A control device for a spark ignition direct injection engine. Gasoline and ethanol provided with fuel discrimination means for directly injecting fuel from a fuel injection valve into a combustion chamber, igniting an air-fuel mixture in the combustion chamber by a spark plug, and determining a content ratio of ethanol in the fuel And a spark-ignition direct-injection engine control device in which the mixed fuel can be used,
Valve timing adjusting means for opening the intake valve during the intake stroke delayed for a predetermined period after the exhaust valve is closed after the intake top dead center;
When it is determined that the first fuel in which the ethanol content in the fuel is 10% or more is used in the low speed / high load region of the engine, the valve timing adjusting means is controlled to control the predetermined period. A first fuel injection control means for performing fuel injection during a period overlapping with at least a part of the predetermined period;
When it is determined that the second fuel in which the ethanol content in the fuel is less than 10% is used in the low-speed / high-load region of the engine, the fuel is consumed during the intake valve opening period in the intake stroke. Second fuel injection control means for performing injection;
Bei to give a,
The fuel injection in a period overlapping with at least a part of the predetermined period of the first fuel is a batch injection,
The fuel injection in the opening period of the intake valve in the intake stroke of the second fuel is divided injection in the intake stroke, or divided injection in the intake stroke and the compression stroke.
Control apparatus for a spark ignition direct injection engine, wherein the this.

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