JP2015214957A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine control device capable of suppressing the occurrence of knocking in an internal combustion engine in which two types of fuels different in octane number are injected.SOLUTION: A control device 1 of an internal combustion engine 3 including a second variable cam phase mechanism 9 capable of changing valve timing of intake valves 4a and 4b so as to set different timing to the intake valves 4a and 4b from each other; and first and second injection valves 11 and 12 injecting ethanol and gasoline, respectively, comprises an ECU 2. The ECU 2 controls the second variable cam phase mechanism 9 so that the valve timing of the first intake valve 4a is earlier than the valve timing of the second intake valve 4b (step 13); controls the first fuel injection valve 11 so as to inject the ethanol at predetermined first timing after timing at which the first intake valve 4a starts to open (step 4); and controls the second fuel injection valve 12 so as to inject the gasoline at predetermined second timing later than the predetermined first timing (step 4).

Description

  The present invention relates to an internal combustion engine including a valve timing changing device that changes valve timings of two intake valves provided for each cylinder so as to be different from each other, and two fuel injection devices that inject fuels having different octane numbers. The present invention relates to a control device.

  Conventionally, what was described in patent document 1 is known as a control apparatus of an internal combustion engine. The internal combustion engine includes a port fuel injection valve and an in-cylinder fuel injection valve. From the port fuel injection valve, ethanol as fuel is injected into the intake passage, and from the in-cylinder fuel injection valve, fuel is supplied. Gasoline is injected directly into the cylinder.

  In the embodiment shown in FIGS. 7 and 8 of this control device, the required voltage Pe for the spark plug is predicted according to the air amount, ignition timing and crank angle detected by the air flow meter (step 31), and this required voltage Pe. Is greater than the threshold value Pt, a ratio between the amount of ethanol injected by the port fuel injector and the amount of gasoline injected by the in-cylinder fuel injector is determined, and based on this ratio, the in-cylinder fuel injector and The port fuel injection valve is driven (step 33). Thereby, the required voltage Pe for the spark plug can be reduced, and misfire is suppressed.

JP 2009-174354 A

  According to the control device of Patent Document 1, in order to suppress misfire without considering the combustion state of the air-fuel mixture in the cylinder, in accordance with the required voltage Pe, the amount of ethanol injected by the port fuel injection valve, Since the ratio to the gasoline injection amount by the in-cylinder fuel injection valve is merely determined, knocking may occur due to the combustion state of the air-fuel mixture in the cylinder.

  The present invention has been made to solve the above problems, and provides an internal combustion engine control device capable of suppressing the occurrence of knocking in an internal combustion engine in which two types of fuel having different octane numbers are injected. With the goal.

  In order to achieve the above object, the invention according to claim 1 can change the valve timings of the two intake valves 4a and 4b provided for each cylinder 3a and the two intake valves 4a and 4b to be different from each other. A valve timing changing device (second variable cam phase mechanism 9), a first fuel injection device (first fuel injection valve 11) for injecting a first fuel (ethanol) having a predetermined octane number, and a lower octane number than the first fuel; A control device 1 for an internal combustion engine 3 having a second fuel injection device (second fuel injection valve 12) for injecting second fuel (gasoline), wherein the internal combustion engine 3 is in a predetermined operating state (second operating region). A valve timing control means (ECU2, step 13) for controlling the valve timing changing device so that one of the two intake valves 4a, 4b has an earlier valve timing than the other. First injection control means (ECU2, step 4) for controlling the first fuel injection device so as to inject the first fuel at a predetermined first timing after the timing at which one of the intake valves 4a starts to open; And a second injection control means (ECU2, step 4) for controlling the second fuel injection device so as to inject the second fuel at a predetermined second timing that is later than one timing.

  According to the control device for an internal combustion engine, when the internal combustion engine is in a predetermined operation state, the valve timing changing device is controlled so that one of the two intake valves has an earlier valve timing than the other. Since the first fuel injection device is controlled so that the first fuel is injected at a predetermined first timing after the intake valve starts to open, only one of the intake valves is opened at the predetermined first timing. The first fuel can be injected at a timing such that a swirl flow is generated in the cylinder by setting the timing when the lift of one intake valve is larger than that of the other intake valve, Thereby, the air-fuel mixture layer of the first fuel can be formed along the inner wall surface of the cylinder. Further, since the second fuel injection device is controlled so as to inject the second fuel at a predetermined second timing that is later than the predetermined first timing, the mixture layer of the second fuel is changed to the mixture layer of the first fuel. It can be formed inside the layer. As a result, an air-fuel mixture layer mainly composed of the first fuel having a high octane number is arranged on the inner wall surface of the cylinder where knocking is likely to occur, and an air-fuel mixture layer mainly composed of the second fuel having a lower octane number is formed Since it is possible to form a layered air-fuel mixture arranged inside, knocking can be effectively suppressed without increasing the octane number of the air-fuel mixture as a whole.

  According to a second aspect of the present invention, in the control device 1 for the internal combustion engine 3 according to the first aspect, the first fuel is injected again at a predetermined third timing that is later than the predetermined second timing. It is further provided with the 3rd injection control means (ECU2, Step 4) which controls a fuel injection device.

  According to the control device for the internal combustion engine, the first fuel injection device is controlled so as to inject the first fuel again at the predetermined third timing that is later than the predetermined second timing. A fuel-air mixture layer composed mainly of one fuel is arranged on the inner wall surface of the cylinder where knocking is likely to occur, and a gas-fuel mixture layer composed mainly of a second fuel having a lower octane number is arranged on the inner side. An air-fuel mixture can be reliably formed. As a result, the occurrence of knocking can be more effectively suppressed.

  According to a third aspect of the present invention, in the control device 1 for the internal combustion engine 3 according to the first or second aspect, the predetermined first timing is such that the lift of the one intake valve 4a starts from the timing when the one intake valve 4a starts to open. The timing is set to a timing during the period up to the vicinity of the same timing as the lift of the other intake valve 4b, the predetermined second timing is later than the predetermined first timing, and the other intake valve 4b is closed. It is characterized by being set to the previous timing.

  According to this control device for an internal combustion engine, the timing during the period from the timing when one of the intake valves begins to open until the timing when the lift of one of the intake valves becomes the same as the lift of the other intake valve, that is, the swirl flow is The first fuel is injected at a timing that occurs in the engine, the second fuel is injected at a timing that is later than the injection timing of the first fuel and before the closing timing of the other intake valve, so the octane number is high The air-fuel mixture layer mainly composed of the first fuel is arranged on the inner wall surface of the cylinder where knocking is likely to occur, and the air-fuel mixture layer mainly composed of the second fuel having a lower octane number is disposed on the inner side. A layered air-fuel mixture can be more reliably formed. As a result, the occurrence of knocking can be further effectively suppressed.

  The invention according to claim 4 is a valve timing changing device (second variable) capable of changing the valve timings of the two intake valves 4a and 4b provided for each cylinder 3a and the two intake valves 4a and 4b to be different from each other. A cam phase mechanism 9), a first fuel injection device (first fuel injection valve 11) for injecting a first fuel (ethanol) having a predetermined octane number, and a second fuel (gasoline) having a lower octane number than the first fuel. The control device 1 for the internal combustion engine 3 having a second fuel injection device (second fuel injection valve 12) that performs two intakes when the internal combustion engine 3 is in a predetermined operation state (second operation region). The valve timing control means (ECU 2, step 13) for controlling the valve timing changing device and the other intake valve 4b start to open so that one of the valves 4a and 4b has an earlier valve timing than the other. A fourth injection control means for controlling the second fuel injection device so as to inject the second fuel at a predetermined fourth timing after the predetermined timing, and at a predetermined fifth timing later than the predetermined fourth timing. And a fifth injection control means for controlling the first fuel injection device so as to inject the fuel.

  According to the control device for an internal combustion engine, when the internal combustion engine is in a predetermined operation state, the valve timing changing device is controlled so that one of the two intake valves has an earlier valve timing than the other. Since the second fuel injection device is controlled so as to inject the second fuel at a predetermined fourth timing after the timing at which the intake valve starts to open, the predetermined fourth timing is set to one intake valve and the other, for example. By setting the timing at which the lifts in the intake valves are equal to each other, or a timing near the front and rear thereof, the second fuel mixture can be formed in the entire cylinder. Further, since the first fuel injection device is controlled to inject the first fuel at a predetermined fifth timing that is later than the predetermined fourth timing, the predetermined fifth timing is set to the lift of one intake valve. Is set after the timing at which it becomes relatively smaller than the other intake valve, so that the first fuel can be injected at a timing at which a swirl flow is generated in the cylinder. An air-fuel mixture layer can be formed along the inner wall surface of the cylinder. As a result, the air-fuel mixture layer mainly composed of the first fuel having a high octane number is disposed on the inner wall surface of the cylinder where knocking is likely to occur, and the air-fuel mixture layer mainly composed of the second fuel having a lower octane number is disposed on the inner side. Since the layered air-fuel mixture is formed in the disposed state, the occurrence of knocking can be effectively suppressed without increasing the octane number of the air-fuel mixture as a whole.

  According to a fifth aspect of the present invention, in the control device 1 for the internal combustion engine 3 according to the fourth aspect, the predetermined fourth timing is a period from a timing at which the other intake valve 4b begins to open to a timing at which the other intake air closes. The predetermined fifth timing is set later than the predetermined fourth timing and is set to a timing before the closing timing of the other intake valve 4b.

  According to the control device for an internal combustion engine, the second fuel is injected at a timing during a period from the timing when the other intake valve starts to open to the timing when the other intake valve closes, which is later than the injection timing of the second fuel. In addition, since the first fuel is injected at a timing before the closing timing of the other intake valve, that is, a timing at which a swirl flow is generated in the cylinder, an air-fuel mixture layer mainly composed of the first fuel having a high octane number is formed. It is possible to more reliably form a stratified mixture in a state where an air-fuel mixture layer mainly composed of a second fuel having a lower octane number is arranged on the inner wall surface side of the cylinder where knocking is likely to occur. . As a result, the occurrence of knocking can be further effectively suppressed.

  The invention according to claim 6 is a valve timing changing device (second variable) capable of changing the valve timings of the two intake valves 4a and 4b provided for each cylinder 3a and the two intake valves 4a and 4b to be different from each other. A cam phase mechanism 9), a first fuel injection device (first fuel injection valve 11) for injecting a first fuel (ethanol) having a predetermined octane number, and a second fuel (gasoline) having a lower octane number than the first fuel. The control device 1 for the internal combustion engine 3 having a second fuel injection device (second fuel injection valve 12) that performs two intakes when the internal combustion engine 3 is in a predetermined operation state (second operation region). The valve timing control means (ECU2, step 13) for controlling the valve timing changing device and the first fuel injection device to control the valve timing changing device so that one of the valves 4a and 4b has an earlier valve timing than the other. The first fuel is injected such that the fuel injection timing and the second fuel injection timing by the second fuel injection device are within the period from the timing when one intake valve 4a starts to open until the timing when the other intake valve 4b closes. While controlling an injection device and a 2nd fuel injection device, the swirl flow formed in cylinder 3a in the injection timing of the 1st fuel from the 1st fuel injection device in the injection timing of the 1st fuel is the 2nd fuel injection device Injection control means (ECU 2, step 4) for setting the timing to become stronger than the swirl flow formed in the cylinder 3a at the injection timing.

  According to the control device for the internal combustion engine, when the internal combustion engine is in a predetermined operation state, the valve timing changing device is controlled so that one of the two intake valves has an earlier valve timing than the other. The injection timing of the first fuel by the fuel injection device and the injection timing of the second fuel by the second fuel injection device are in a period from the timing after one intake valve begins to open until the timing when the other intake valve closes. The first fuel injection device and the second fuel injection device are controlled. In that case, the swirl flow formed in the cylinder at the injection timing of the second fuel injection device is the swirl flow formed in the cylinder at the injection timing of the first fuel from the injection timing of the first fuel from the first fuel injection device. Since the timing is set to be stronger than the flow, the mixture layer of the second fuel is formed inside the mixture layer of the first fuel while the mixture layer of the first fuel is formed along the inner wall surface of the cylinder. can do. As a result, an air-fuel mixture layer mainly composed of the first fuel having a high octane number is arranged on the inner wall surface of the cylinder where knocking is likely to occur, and an air-fuel mixture layer mainly composed of the second fuel having a lower octane number is formed Since it is possible to form a layered air-fuel mixture arranged inside, knocking can be effectively suppressed without increasing the octane number of the air-fuel mixture as a whole.

  The invention according to claim 7 is the control device 1 for the internal combustion engine 3 according to any one of claims 1 to 6, wherein the first fuel injection device is an intake passage 10 upstream of the two intake valves 4a and 4b. The second fuel injection device is provided so as to inject the second fuel directly into the cylinder 3a.

  According to this control device for an internal combustion engine, the first fuel injection device is provided so as to inject the first fuel into the intake passage upstream of the two intake valves. By appropriately setting the timing at which the fuel flows into the cylinder via the intake port, the air-fuel mixture of the first fuel can flow into the cylinder in a swirl state. Furthermore, since the second fuel injection device is provided so as to inject the second fuel directly into the cylinder, the mixture layer mainly composed of the first fuel having a high octane number is likely to knock. It is possible to reliably form a stratified mixture in a state where it is arranged on the wall surface side and an air-fuel mixture layer mainly composed of the second fuel having a lower octane number is arranged on the inner side. As a result, the operational effects of the invention according to any one of claims 1 to 4 can be reliably achieved.

It is a figure showing typically composition of a control device concerning one embodiment of the present invention, and an internal-combustion engine to which this is applied. It is a perspective view which shows typically the structure of an intake valve mechanism. It is a figure which shows a lift curve when the cam phase of a 1st intake valve and a 2nd intake valve is set to the most advanced angle position and the most retarded angle position by the 1st variable cam phase mechanism. It is a figure which shows a lift curve when the phase difference between the 1st intake valve 4a and the 2nd intake valve 4b is set to the value 0 by the 2nd variable cam phase mechanism. It is a figure which shows a lift curve when the phase difference between the 1st intake valve 4a and the 2nd intake valve 4b is set to the maximum value by the 2nd variable cam phase mechanism. It is a flowchart which shows a fuel-injection control process. It is a flowchart which shows a valve timing control process. FIG. 5A is a plan view and FIG. 5B is a front view schematically showing the flow of the air-fuel mixture in the cylinder when only the first intake valve is in the open state at the initial stage of the intake stroke. (A) Plane schematically showing the flow of the air-fuel mixture in the cylinder and the fuel injection of the second fuel injection valve when the first intake valve and the second intake valve are open at the same lift in the middle of the intake stroke It is a figure and (b) front view. FIG. 5A is a plan view and FIG. 5B is a front view schematically showing the flow of the air-fuel mixture in the cylinder when only the first intake valve is in the open state in the latter stage of the intake stroke. It is a figure which shows the layered air-fuel | gaseous mixture produced | generated when the operation area | region of an internal combustion engine exists in the high knock area | region where a knocking is easy to generate | occur | produce.

  Hereinafter, an internal combustion engine control apparatus according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the control device 1 of the present embodiment includes an ECU 2, and various control processes such as a fuel injection control process are executed by the ECU 2 as will be described later.

  The internal combustion engine (hereinafter referred to as “engine”) 3 is an in-line four-cylinder type having four sets of cylinders 3a and pistons 3b (only one set is shown), and is mounted on a vehicle (not shown). As shown in FIGS. 1 and 2, the engine 3 includes first and second intake valves 4a and 4b provided for each cylinder 3a, and exhaust valves 5 and 5 (one for each cylinder 3a). Only, and an intake valve mechanism 6 for opening and closing the first and second intake valves 4a and 4b.

  Specifically, the intake valve mechanism 6 is configured in the same manner as that proposed by the present applicant in Japanese Patent No. 4747158 and the like. The first variable cam phase mechanism 8 and the second variable cam phase mechanism 9 are configured.

  The intake camshaft 7 is a combination of an inner shaft and an outer shaft (both not shown), and the first intake cam 7a is attached to the inner shaft so as to rotate together. During the rotation of the intake camshaft 7, the first intake valve 4a is driven by the first intake cam 7a, and accordingly the first intake port 10a (see FIGS. 8 to 10) is opened and closed.

  The outer shaft is disposed outside the inner shaft, and is disposed so as to be rotatable around an axis within a predetermined range relative to the inner shaft. The second intake cam 7b is integrated with the outer shaft. It is attached to rotate. During the rotation of the intake camshaft 7, the second intake valve 4b is driven by the second intake cam 7b, and accordingly opens and closes the second intake port 10b (see FIGS. 8 to 10).

  Further, the first variable cam phase mechanism 8 continuously steps the relative phase of the intake camshaft 7 relative to the crankshaft 3c (hereinafter referred to as “intake cam phase”) CAIN within a predetermined range to the advance side or the retard side. It is to be changed and is provided at the end of the intake camshaft 7 on the intake sprocket (not shown) side.

  The first variable cam phase mechanism 8 is configured in the same manner as that proposed by the present applicant in the above-mentioned Japanese Patent No. 4747158 and the like. A valve 8a and the like are provided. In the case of the first variable cam phase mechanism 8, the intake cam phase CAIN is set to a predetermined maximum advance value CAINad and a predetermined maximum delay angle by controlling the first cam phase control valve 8a by a drive signal from the ECU 2. It is continuously changed between the values CAINrt.

  In this case, the two intake valves 4a and 4b have a solid line in FIG. 3 when the intake cam phase CAIN is controlled to a predetermined maximum advance value CAINad in a state where the phase difference DCAIN = 0 described later. When the intake cam phase CAIN is controlled to a predetermined most retarded angle value CAINrt, it opens and closes at the most retarded angle timing indicated by a two-dot chain line in FIG. That is, the valve timing of the two intake valves 4a and 4b is set between the most advanced timing shown by the solid line in FIG. 3 and the most retarded timing shown by the two-dot chain line in FIG. It is changed steplessly. Note that CA on the horizontal axis in FIG. 3 is a crank angle.

  On the other hand, the second variable cam phase mechanism 9 (valve timing changing device) has a relative phase difference between the first intake cam 7a and the second intake cam 7b, that is, the first intake valve 4a and the second intake valve 4b. The phase difference DCAIN between the intake camshaft 7 and the first variable cam phase mechanism 8 is changed in a stepless manner within a predetermined range.

  The second variable cam phase mechanism 9 is configured in the same manner as that proposed by the present applicant in the above-mentioned Japanese Patent No. 4747158, etc., and detailed description thereof is omitted, but the second cam phase control is omitted. A valve 9a is provided. In the case of the second variable cam phase mechanism 9, the second cam phase control valve 9a is controlled by a drive signal from the ECU 2, whereby the phase difference DCAIN is continuously set between the value 0 and a predetermined maximum value DCAINmax. Change. The predetermined maximum value DCAINmax is set to a predetermined positive value.

  In this case, the two intake valves 4a and 4b open and close at the same phase timing shown in FIG. 4 when DCAIN = 0, and open and close at the maximum phase difference timing shown in FIG. 5 when DCAIN = DCAINmax. That is, as shown in FIG. 5, when it is at the maximum phase difference timing, the second intake valve 4b opens and closes at a timing delayed by DCAINmax compared to the first intake valve 4a. With the above configuration, the valve timing of the two intake valves 4a and 4b is steplessly changed between the same phase timing shown in FIG. 4 and the maximum phase difference timing shown in FIG. 5 by the second variable cam phase mechanism 9. Is done.

  The two exhaust valves 5 and 5 are driven by an exhaust valve mechanism (not shown) during operation of the engine 3 to discharge the combustion gas in the cylinder 3a to the exhaust passage 15 side.

  Further, the engine 3 is provided with a first fuel injection valve 11, a second fuel injection valve 12, a spark plug 13, and a crank angle sensor 20. In this case, the first fuel injection valve 11, the second fuel injection valve 12, and the spark plug 13 are all provided for each cylinder 3a (only one is shown).

  First, the first fuel injection valve 11 (first fuel injection device) injects ethanol from a fuel tank (not shown) and is upstream of the branch start portions of the two intake ports 10a and 10b of each cylinder 3a. It is attached to the intake manifold so as to face the intake passage 10. As a result, when both of the two intake valves 4a and 4b are in the open state, the spray of ethanol injected from the first fuel injection valve 11 enters the cylinder 3a via the two intake ports 10a and 10b. Inflow (see FIG. 9).

  The second fuel injection valve 12 (second fuel injection device) injects gasoline from a fuel tank (not shown), and is attached to the cylinder head so as to face the cylinder 3a. Thereby, the gasoline is directly injected into the cylinder 3a by the second fuel injection valve 12 (see FIGS. 9 and 10).

  Further, both the first fuel injection valve 11 and the second fuel injection valve 12 described above are electrically connected to the ECU 2, and the ethanol injection timing of the first fuel injection valve 11 by the ECU 2 as will be described later. And the injection amount and the injection timing and the injection amount of gasoline by the second fuel injection valve 12 are controlled. That is, fuel injection control is executed.

  In addition to this, the spark plug 13 is also electrically connected to the ECU 2, and the ignition timing of the air-fuel mixture by the spark plug 13 is controlled by the ECU 2. That is, ignition timing control is executed.

  On the other hand, the crank angle sensor 20 includes a magnet rotor and an MRE pickup, and outputs a CRK signal and a TDC signal, which are pulse signals, to the ECU 2 as the crankshaft 3c rotates. The CRK signal is output at one pulse every predetermined crank angle (for example, 2 °), and the ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal.

  The TDC signal is a signal indicating that the piston 3b of each cylinder 3a is at a predetermined crank angle position slightly ahead of the TDC position of the intake stroke. In the case of the four-cylinder engine of this embodiment, the crank angle One pulse is output every 180 °.

  Further, an accelerator opening sensor 21 is electrically connected to the ECU 2. The accelerator opening sensor 21 detects a depression amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) of the vehicle, and outputs a detection signal indicating it to the ECU 2.

  On the other hand, the ECU 2 is composed of a microcomputer including a CPU, RAM, ROM, an I / O interface (all not shown), and the like based on the detection signals of the various sensors 20 and 21 described below. As described above, various control processes such as a fuel injection control process are executed. In the present embodiment, the ECU 2 corresponds to valve timing control means, first to fifth injection control means, and injection control means.

  Next, the fuel injection control process will be described with reference to FIG. This fuel injection control process controls the injection timing and injection amount of ethanol by the first fuel injection valve 11 and the injection timing and injection amount of gasoline by the second fuel injection valve 12, and the ECU 2 controls the TDC signal. It is executed in synchronization with the generation timing.

  As shown in the figure, first, in step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), a required torque TRQ is searched by searching a map (not shown) according to the engine speed NE and the accelerator pedal opening AP. Is calculated.

  Subsequently, it progresses to step 2 and performs a driving | running | working area | region determination process. In this operation region determination process, based on the engine speed NE and the required torque TRQ, it is determined whether or not the operation region of the engine 3 is in a high knock region where knocking is likely to occur, such as a high rotation & high load region, Based on the determination result, the value of the high knock flag F_KNOCK is set. Specifically, the high knock flag F_KNOCK is set to “1” when the operation region of the engine 3 is in the high knock region, and is set to “0” otherwise.

  In step 3 following step 2, it is determined whether or not the high knock flag F_KNOCK described above is “1”. When the determination result is YES, it is determined that the ethanol & gasoline injection control process should be executed because the operation region of the engine 3 is in a high knock region where knocking is likely to occur. & Execute gasoline injection control process.

  In this ethanol & gasoline injection control process, only the ethanol injection by the first fuel injection valve 11 is executed at the initial timing of the intake stroke, and only the gasoline injection by the second fuel injection valve 12 is executed at the middle timing of the intake stroke. While being executed, only ethanol injection by the first fuel injection valve 11 is executed again at a later timing of the intake stroke. As a result, in the cylinder 3a, as will be described later, a layered mixture in which the ethanol spray is mainly disposed on the inner wall surface side of the cylinder 3a and the gasoline spray is mainly disposed on the center side of the cylinder 3a. Is formed (see FIG. 11).

  In this case, the first and second ethanol injection timings and injection amounts by the first fuel injection valve 11 and the gasoline injection timing and injection amount by the second fuel injection valve 12 are the engine speed NE, the required torque TRQ, It is determined according to the target intake cam phase CAINcmd, the target phase difference DCAINcmd, and the like. More specifically, at the first ethanol injection start timing (predetermined first timing), the lifts of the first intake valve 4a and the second intake valve 4b are the same from the timing at which the first intake valve 4a starts to open. It is set between the same lift timing (for example, the crank angle CA = CA1 timing in FIG. 5).

  The gasoline injection start timing (predetermined second and fourth timings) is from the same lift timing to the timing at which the second intake valve 4b is closed, that is, the lift of the second intake valve 4b is the first intake. A period larger than the lift of the valve 4a is set. Furthermore, the second injection start timing (predetermined third and fifth timings) of ethanol is set between the gasoline injection start timing and the timing at which the second intake valve 4b is closed. As described above, after the ethanol & gasoline injection control process is executed in step 4, the present process is terminated.

  On the other hand, when the determination result in step 3 is NO, it is determined that the gasoline injection control process should be executed because the operation region of the engine 3 is in a region where knocking is unlikely to occur, and the process proceeds to step 5. The gasoline injection control process is executed. In this gasoline injection control process, the injection timing and injection amount of gasoline by the second fuel injection valve 12 are determined according to the engine speed NE, the required torque TRQ, the target intake cam phase CAINcmd, the target phase difference DCAINcmd, and the like. Accordingly, the opening timing and opening time of the second fuel injection valve 12 are controlled.

  Next, the valve timing control process will be described with reference to FIG. In this valve timing control process, the intake cam phase CAIN and the phase difference DCAIN are controlled by driving the first variable cam phase mechanism 8 and the second variable cam phase mechanism 9, respectively. (For example, 10 msec).

  As shown in the figure, first, in step 10, a target cam phase CAINcmd is calculated by searching a map (not shown) according to the engine speed NE and the required torque TRQ. This target cam phase CAINcmd corresponds to the target value of the intake cam phase CAIN.

  Next, the routine proceeds to step 11 where a target phase difference DCAINcmd is calculated by searching a map (not shown) according to the engine speed NE and the required torque TRQ. The target phase difference DCAINcmd is a value corresponding to the target value of the phase difference DCAIN. Specifically, when the operation region of the engine 3 is in a predetermined first operation region (for example, a low load & high rotation region), When the value is set to 0 and is in the second operation region (predetermined operation state) that is an operation region other than the first operation region, it is within a range from a positive value larger than the value 0 to the predetermined maximum value DCAINmax described above. Set to a value. In particular, when the operating range of the engine 3 is in the above-described high knock range, the predetermined maximum value DCAINmax and a value in the vicinity thereof are set.

  In step 12 following step 11, a first cam phase control process is executed. In this first cam phase control process, the value of the control input signal corresponding to the target cam phase CAINcmd calculated in step 10 is calculated, and the control input signal calculated in this way is supplied to the first variable cam phase mechanism 8. . Thereby, the actual cam phase CAIN is controlled to be the target cam phase CAINcmd.

  Next, the routine proceeds to step 13 where a second cam phase control process is executed. In this second cam phase control process, the value of the control input signal corresponding to the target phase difference DCAINcmd calculated in step 11 is calculated, and the control input signal thus calculated is supplied to the second variable cam phase mechanism 9. . Thereby, the actual phase difference DCAIN is controlled to be the target phase difference DCAINcmd.

  As described above, after the second cam phase control process is executed in step 13, this process is terminated.

  Next, referring to FIGS. 8 to 11, when the operation region of the engine 3 is in the high knock region, the mixing in the cylinder 3 a when the fuel injection control process and the valve timing control process are executed as described above. The generating operation of the ki will be described.

  First, when the operation region of the engine 3 is in the high knock region, as described above, the target phase difference DCAINcmd is set to the predetermined maximum value DCAINmax and a value in the vicinity thereof in the valve timing control process. DCAIN is controlled to be a value in the vicinity of DCAINmax.

  When the phase difference DCAIN is controlled in this way, the first intake valve 4a starts to open at an earlier timing than the second intake valve 4b in the early stage of the intake stroke, so that the air in the intake passage 10 is As indicated by the arrow Y1 in 8 (a) and (b), the air flows into the cylinder 3a only through the first intake port 10a. Thereby, a swirl flow is formed in the cylinder 3a.

  In that case, in the ethanol & gasoline injection control process of the fuel injection control process, between the timing when the first intake valve 4a starts to open and the same lift timing when the lifts of the first intake valve 4a and the second intake valve 4b are the same. Only the ethanol injection by the first fuel injection valve 11 is executed, so that the mixture of ethanol flows as a swirl flow from the upper side to the lower side in the cylinder 3a. Thereby, an air-fuel mixture layer is formed mainly on the inner wall surface side of the cylinder 3a.

  Then, in the middle stage of the intake stroke, the air in the intake passage 10 near the same lift timing at which the lifts of the first intake valve 4a and the second intake valve 4b are the same is shown in FIGS. 9 (a) and 9 (b). As indicated by the arrow Y2, the air flows into the cylinder 3a at substantially the same flow rate through both the first intake port 10a and the second intake port 10b. Thereby, the air in the intake passage 10 flows into the cylinder 3a with almost no swirl flow.

  In that case, as described above, in the fuel injection control process, the gasoline injection from the second fuel injection valve 12 is executed during the period from the same lift timing to the timing at which the second intake valve 4b is closed. The air-fuel mixture layer containing the main component is formed inside the air-fuel mixture layer containing ethanol as the main component, that is, on the center side of the cylinder 3a.

  Further, at the end of the intake stroke, as the first intake valve 4a closes, the air in the intake passage 10 becomes the second intake air as shown by the arrow Y3 in FIGS. 10 (a) and 10 (b). It flows into the cylinder 3a only through the port 10b. Thereby, the swirl flow in the cylinder 3a becomes strong again. At that time, as described above, the second injection of ethanol by the first fuel injection valve 11 is executed after the gasoline injection start timing, so that the air-fuel mixture formed on the inner wall surface side of the cylinder 3a is The ethanol concentration increases in the layer.

  As a result of the above operation, when the operating range of the engine 3 is in the high knock range, as shown in FIG. 11, an air-fuel mixture layer mainly composed of gasoline is arranged on the center side of the cylinder 3a so as to enclose it. In addition, a layered mixture in which an air-fuel mixture layer containing ethanol as a main component is disposed on the inner wall surface side of the cylinder 3a is formed in the cylinder 3a. As described above, according to the control device 1 of the present embodiment, the gas mixture layer mainly composed of ethanol having a high octane number is arranged on the inner wall surface side of the cylinder 3a where knocking is likely to occur, and the octane number is lower than that. A mixture of gas mixtures with gasoline as the main component can be formed on the inside of the mixture, so knocking can be effectively suppressed without increasing the octane number of the mixture as a whole. Can do.

  The embodiment is an example in which the second variable cam phase mechanism 9 is used as the valve timing changing device. However, the valve timing changing device of the present invention is not limited to this, and the valve timings of the two intake valves are different from each other. As long as it can be changed as such. For example, as a valve timing changing device, two electromagnetic valve mechanisms that open and close two intake valves by the power of an electromagnet may be used, and one of the two intake valves is driven by a fixed valve mechanism, A type in which the other is driven by an electromagnetic valve mechanism may be used.

  The embodiment is an example in which ethanol and gasoline are used as the first fuel and the second fuel. However, the first fuel and the second fuel of the present invention are not limited to these, and the second fuel is more than the first fuel. May have a low octane number, in other words, the first fuel may have a higher octane number than the second fuel. For example, MTBE (methyl tertiary butyl ether) or ETBE (ethyl tertiary butyl ether) may be used as the first fuel, and gasoline may be used as the second fuel.

  Further, in the embodiment, the ethanol injection as the first fuel is executed in the early stage of the intake stroke, the gasoline injection as the second fuel is executed in the middle stage of the intake stroke, and the ethanol re-injection is executed in the later stage of the intake stroke. However, the injection method of the first fuel and the second fuel is not limited to this, and any method may be used as long as it can generate a layered mixture as shown in FIG. For example, in the injection method of the embodiment, the ethanol injection in the initial stage of the intake stroke may be omitted, the gasoline injection may be executed in the middle of the intake stroke, and the ethanol re-injection may be executed in the latter stage of the intake stroke. Good.

  Further, in the injection method of the embodiment, the ethanol re-injection in the later stage of the intake stroke is omitted, the ethanol injection as the first fuel is executed at the beginning of the intake stroke, and the gasoline injection as the second fuel is performed in the middle of the intake stroke. It may be configured to execute. Further, the ethanol injection timing may be set to a timing at which the swirl flow formed in the cylinder 3a at the ethanol injection timing becomes stronger than the swirl flow formed in the cylinder 3a at the gasoline injection timing.

  On the other hand, the embodiment is an example in which a port fuel injection type is used as the first fuel injection valve, but the first fuel injection valve of the present invention is not limited to this, but is a cylinder fuel injection type. May be used. In this case, it is advantageous to use a port fuel injection type as the first fuel injection valve from the viewpoint of appropriately generating the stratified mixture as shown in FIG.

  The embodiment is an example in which the control device of the present invention is applied to an internal combustion engine for a vehicle. However, the control device of the present invention is not limited to this, and is an internal combustion engine for ships or an internal combustion engine for other industrial equipment. Applicable to institutions.

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 ECU (Valve timing control means, 1st injection control means, 2nd injection control means, 3rd injection control means, 4th injection control means, 5th injection control means, injection control means)
3 Internal combustion engine 3a Cylinder 4a First intake valve 4b Second intake valve 9 Second variable cam phase mechanism (valve timing changing device)
10 Intake passage 11 First fuel injection valve (first fuel injection device)
12 Second fuel injection valve (second fuel injection device)

Claims (7)

Two intake valves provided for each cylinder, a valve timing changing device capable of changing valve timings of the two intake valves to be different from each other, a first fuel injection device for injecting a first fuel having a predetermined octane number, A control device for an internal combustion engine having a second fuel injection device for injecting a second fuel having a lower octane number than the first fuel,
Valve timing control means for controlling the valve timing changing device so that one of the two intake valves has an earlier valve timing than the other when the internal combustion engine is in a predetermined operating state;
First injection control means for controlling the first fuel injection device to inject the first fuel at a predetermined first timing after the timing at which the one intake valve starts to open;
Second injection control means for controlling the second fuel injection device so as to inject the second fuel at a predetermined second timing that is later than the predetermined first timing;
A control device for an internal combustion engine, comprising:   The apparatus further comprises third injection control means for controlling the first fuel injection device such that the first fuel is injected again at a predetermined third timing that is later than the predetermined second timing. Item 2. A control device for an internal combustion engine according to Item 1.   The predetermined first timing is set to a timing during a period from the timing at which the one intake valve starts to open until the timing at which the lift of the one intake valve becomes the same as the lift of the other intake valve. 3. The internal combustion engine according to claim 1, wherein the predetermined second timing is set to a timing later than the predetermined first timing and before the timing at which the other intake valve is closed. Engine control device. Two intake valves provided for each cylinder, a valve timing changing device capable of changing valve timings of the two intake valves to be different from each other, a first fuel injection device for injecting a first fuel having a predetermined octane number, A control device for an internal combustion engine having a second fuel injection device for injecting a second fuel having a lower octane number than the first fuel,
Valve timing control means for controlling the valve timing changing device so that one of the two intake valves has an earlier valve timing than the other when the internal combustion engine is in a predetermined operating state;
Fourth injection control means for controlling the second fuel injection device so as to inject the second fuel at a predetermined fourth timing after the timing at which the other intake valve starts to open;
Fifth injection control means for controlling the first fuel injection device so as to inject the first fuel at a predetermined fifth timing that is later than the predetermined fourth timing;
A control device for an internal combustion engine, comprising:   The predetermined fourth timing is set to a timing during a period from a timing at which the other intake valve starts to open to a timing at which the other intake valve closes, and the predetermined fifth timing is the predetermined fourth timing. 5. The control device for an internal combustion engine according to claim 4, wherein the control device is set at a timing later than the timing and before the timing at which the other intake valve is closed. Two intake valves provided for each cylinder, a valve timing changing device capable of changing valve timings of the two intake valves to be different from each other, a first fuel injection device for injecting a first fuel having a predetermined octane number, A control device for an internal combustion engine having a second fuel injection device for injecting a second fuel having a lower octane number than the first fuel,
Valve timing control means for controlling the valve timing changing device so that one of the two intake valves has an earlier valve timing than the other when the internal combustion engine is in a predetermined operating state;
The timing at which the other intake valve closes after the timing at which the one intake valve begins to open is determined based on the injection timing of the first fuel by the first fuel injection device and the injection timing of the second fuel by the second fuel injection device. The first fuel injection device and the second fuel injection device are controlled so that the injection timing of the first fuel from the first fuel injection device is controlled so that the first fuel injection device is injected. Injection control means for setting the swirl flow formed in the cylinder at the timing to be stronger than the swirl flow formed in the cylinder at the injection timing of the second fuel injection device;
A control device for an internal combustion engine, comprising: The first fuel injection device is provided to inject the first fuel into an intake passage upstream of the two intake valves;
The control apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein the second fuel injection device is provided so as to inject the second fuel directly into a cylinder.

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