WO2022113511A1 - Valve control device, and valve control method - Google Patents

Abstract

Provided is a valve control device that controls driving to open/close a first intake valve and a second intake valve and that is provided to an intake port which is in communication with the inside of a cylinder of an internal combustion engine. The valve control device comprises a control device that controls a lift amount of the first intake valve and a lift amount of the second intake valve so that the relationship between the lift amount of the first intake valve and the lift amount of the second intake valve is reversed at least once during one cycle of the internal combustion engine.

Description

Valve control device and valve control method

The present invention relates to a valve control device and a valve control method for controlling an intake valve of an engine.

In recent years, various efforts have been made to meet the demands for improving engine performance such as improving fuel efficiency and reducing exhaust gas for automobiles, and as one of the countermeasures, the flow of air sucked into the cylinder of the engine (hereinafter referred to as "inside the cylinder"). Abbreviated as "flow"). In particular, in the method of injecting fuel directly into the cylinder called DI (Direct Injection), it is necessary to mix the injected fuel and the sucked air in an extremely short time, so the strength of the in-cylinder flow is the air-fuel mixture. It has a large effect on the formation and subsequent combustion performance.

As a method of strengthening the in-cylinder flow, a method of devising the shape of the intake port and the shape of the piston crown surface, or a method of partitioning the inside of the intake port up and down and using a tumble control valve to stop the flow to either the top or bottom to control the flow velocity. There is a way to raise it and strengthen the tumble, which is a vertical vortex in the cylinder. Further, there is a method of generating a swirl (swirl flow) which is a lateral vortex in the cylinder by blocking the flow to one of the left and right intake ports with a swirl control valve.

Also, as another means, the in-cylinder flow changes by controlling the valve timing of the intake valve and exhaust valve. In this regard, Patent Document 1 discloses a method of generating a swirl in a cylinder by a difference in valve profiles of two intake valves.

Japanese Unexamined Patent Publication No. 11-22991

The technique described in Patent Document 1 makes the valve lift curves of the two intake valves different, and generates a swirl in the cylinder due to the difference in the amount of air sucked into the cylinder from each intake valve, but the swirl strength is not always sufficient. Was not obtained.

From the above situation, a method that makes it possible to further strengthen the in-cylinder flow when a swirl is generated in the cylinder due to the difference in opening between the two intake valves has been desired.

In order to solve the above problems, the valve control device of one aspect of the present invention controls the opening / closing drive of the first intake valve and the second intake valve provided in the intake port communicating with the inside of the cylinder of the internal combustion engine. The first intake valve is a valve control device that reverses the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve at least once during one cycle of the internal combustion engine. A control device for controlling the lift amount of the second intake valve and the lift amount of the second intake valve is provided.

According to at least one aspect of the present invention, a swirl can be generated in the cylinder by the difference in opening degree between the two intake valves, and the rotation direction of the swirl can be reversed in the middle. As a result, it becomes possible to further strengthen the in-cylinder flow.
Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.

It is a schematic block diagram of the engine to which this invention is applied. It is a schematic diagram which shows the intake valve and the exhaust valve. It is a block diagram which shows the hardware configuration example of an ECU. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of two intake valves which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the change of the direction of a swirl in a combustion chamber when two intake valves and are operated according to the valve lift curve of FIG. It is a simulation result which shows the change of the swirl ratio in the 1st Embodiment of this invention. It is a simulation result which shows the change of the tumble ratio in the 1st Embodiment of this invention. It is a simulation result which shows the change of the kinetic energy of the turbulent flow in the 1st Embodiment of this invention. It is a simulation result which shows the change of the kinetic energy of the average flow in 1st Embodiment of this invention. It is a simulation result which analyzed the sensitivity of the swirl ratio with respect to the phase difference of the valve timing which maximizes the valve lift amount in the 1st Embodiment of this invention. It is a simulation result which analyzed the sensitivity of the tumble ratio with respect to the phase difference of the valve timing which maximizes the valve lift amount in the 1st Embodiment of this invention. It is a simulation result which analyzed the sensitivity of the kinetic energy of the turbulence with respect to the phase difference of the valve timing which maximizes the valve lift amount in the 1st Embodiment of this invention. It is a simulation result which analyzed the sensitivity of the kinetic energy of the average flow with respect to the phase difference of the valve timing which maximizes the valve lift amount in the 1st Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of two intake valves which concerns on 2nd Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on 3rd Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on 4th Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on 5th Embodiment of this invention. It is a schematic diagram which shows the change of the direction of a swirl in a combustion chamber when two intake valves and are operated according to the valve lift curve of FIG. It is another operation characteristic curve diagram (valve lift curve) of the intake valve in 5th Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on 6th Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on 7th Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on 1st example of the 9th Embodiment of this invention. It is an operation characteristic curve diagram (valve lift curve) which showed the relationship between the valve lift amount and the crank angle of the intake valve which concerns on the 2nd example of the 9th Embodiment of this invention.

Hereinafter, examples of embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The explanation will be given in the following order. In the present specification and the accompanying drawings, components having substantially the same function or configuration are designated by the same reference numerals, and duplicate description will be omitted.
1. 1. First embodiment (example in which there is a phase difference between the peak timings of the two intake valves)
2. 2. Second embodiment (an example in which there is a flat portion on the valve opening side or valve closing side of the valve lift curve)
3. 3. Third embodiment (example in which the peak timing and the peak value of the two intake valves are different)
4. Fourth embodiment (example in which the peak timings of the two intake valves are both advanced)
5. Fifth Embodiment (Example of one of two intake valves having one peak and the other having two peaks)
6. Sixth embodiment (an example where one of the two intake valves has a flat portion on the valve lift curve)
7. Seventh Embodiment (Example of having a plurality of peaks in the valve lift curve of two intake valves)
8. Eighth embodiment (an example in which the peak timings of the two intake valves are the same, the peak values are different, and the valve closing timings are different).
9. Ninth embodiment (an example in which the peak timings of the two intake valves are the same, the peak values are different, and the on-off valve timings are different).

First, a schematic configuration of an engine to which the present invention is applied will be described with reference to FIGS. 1 and 2.
FIG. 1 is a schematic configuration diagram of an engine.
FIG. 2 is a schematic view showing an intake valve and an exhaust valve.

In FIG. 1, in the engine 100, an intake port 4 and an exhaust port 5 are connected to a combustion chamber 12 composed of a cylinder 1, a cylinder head 2, and a piston 3. The connection portion of the intake port 4 with the cylinder head 2 is branched into a first intake port and a second intake port. The first intake port is provided with an intake valve 6a, and the second intake port is provided with an intake valve 6b. Further, the connection portion of the exhaust port 5 with the cylinder head 2 is branched into a first exhaust port and a second exhaust port. The first exhaust port is provided with an exhaust valve 7a, and the second exhaust port is provided with an exhaust valve 7b. A pair of intake valves 6a and 6b are configured to partition the combustion chamber 12 from the intake port 4. Further, the pair of exhaust valves 7a and 7b is configured to partition the combustion chamber 12 from the exhaust port 5.

The engine 100 mixes between the intake port 4 and the combustion chamber 12 and between the exhaust port 5 and the combustion chamber 12 by the vertical movement of the piston 3 and the opening and closing of the intake valves 6a and 6b and the exhaust valves 7a and 7b. It is a mechanism to take care of yourself. That is, in a normal operating state, the intake valves 6a and 6b are closed in the exhaust stroke, the piston 3 rises, and the exhaust valves 7a and 7b open to move from the combustion chamber 12 to the exhaust port 5. Exhaust is done. In the subsequent intake stroke, the exhaust valves 7a and 7b are in a closed state, the piston 3 descends, and the intake valves 6a and 6b open, so that intake air is taken from the intake port 4 into the combustion chamber 12.

The intake valves 6a and 6b are opened and closed by the intake valve drive devices 8a and 8b. Here, the intake valve drive devices 8a and 8b may have cam shapes such that the valve lift curves are different from each other. Further, the intake valves 6a and 6b may be electromagnetic devices or mechanical devices capable of independently changing the valve lift curves. In the case of a configuration in which the valve lift curve can be changed independently, it is also possible to switch the valve lift curve depending on the operating area. For example, in the high load operation region, a valve lift curve set to a value in which the valve lift amount is larger than that in the low load operation region may be used. Further, the exhaust valves 7a and 7b are opened and closed by the exhaust valve drive devices 9a and 9b.

Further, a fuel injection valve 10 for injecting fuel and a spark plug 11 for igniting the air-fuel mixture are installed in the combustion chamber 12. The crank angle sensor 14 detects the rotation angle position of the crank 13 which is a shaft (axis) for converting the reciprocating motion of the piston 3 into the rotational motion, and outputs an output signal to the engine control unit (ECU). It is a device to send to 20.

The engine 100 is composed of the above parts. The intake valve drive devices 8a and 8b, the exhaust valve drive devices 9a and 9b, the fuel injection valve 10, and the spark plug 11 are controlled by the ECU 20. The ECU 20 is an example of a valve control device.

That is, the ECU 20 controls the valve timing, the valve lift curve, and the like related to the on-off valves of the intake valves 6a and 6b via the intake valve drive devices 8a and 8b. Further, the ECU 20 controls the valve timing, the valve lift curve, and the like related to the on-off valves of the exhaust valves 7a and 7b via the exhaust valve drive devices 9a and 9b. Further, the ECU 20 controls the fuel injection timing, the injection pulse width, and the like in the fuel injection valve 10, and controls the ignition timing and the like in the spark plug 11.

[ECU hardware configuration]
FIG. 3 is a block diagram showing a hardware configuration example of the ECU 20.
The ECU 20 includes an input circuit 191 and an A / D conversion unit 192, a CPU (Central Processing Unit) 193 which is a central processing unit, a ROM (Read Only Memory) 194, a RAM (Random Access Memory) 195, and an output circuit 196. There is. Further, the ECU 20 includes a communication circuit 199. The ECU 20 is composed of, for example, a microcomputer.

The CPU 193 expands the program stored in the ROM 194 (an example of the storage unit) into the RAM 195 and executes it, thereby realizing a plurality of functions described later in the present embodiment. The CPU 193 is an example of a control device. For example, the CPU 193 generates a control signal for controlling the opening / closing drive of the intake valves 6a and 6b, and controls the output to the intake valve drive devices 8a and 8b and the exhaust valve drive devices 9a and 9b.

The input circuit 191 takes in the signal output from the sensors 200 as an input signal 190. The sensors 200 are, for example, a throttle sensor, a water temperature sensor, a crank angle sensor 14, an intake cam angle sensor, an exhaust cam angle sensor, and the like. When the input signal 190 is an analog signal (for example, a signal from a water temperature sensor, a throttle sensor, etc.), the input circuit 191 removes a noise component from the input signal 190 and converts the signal after noise removal into A / D. Output to unit 192.

The A / D conversion unit 192 converts an analog signal into a digital signal and outputs it to the CPU 193. The CPU 193 takes in the digital signal output from the A / D conversion unit 192 and executes a control logic (program) stored in a storage medium such as ROM 194 to execute a wide variety of operations, diagnosis, control, and the like. .. The calculation result of the CPU 193 and the conversion result of the A / D conversion unit 192 are temporarily stored in the RAM 195. Further, in the present embodiment, as the ROM 194, a non-volatile memory such as an EEPROM (Electrically Erasable and Programmable Read Only Memory) whose contents can be rewritten is used. For example, a program in which an algorithm for realizing the valve control method of the present invention is described is stored in ROM 194 or an auxiliary storage device (not shown).

The calculation result of the CPU 193 is output as a control signal 197 from the output circuit 196, and is used for controlling a controlled object 210 such as an actuator for driving the engine 100. The control target is, for example, an intake valve drive device 8a, 8b, an exhaust valve drive device 9a, 9b, a fuel injection valve 10, a spark plug 11, and the like.

When the input signal 190 is a digital signal, the input signal 190 is sent directly from the input circuit 191 to the CPU 193 via the signal line 198, and the CPU 193 executes necessary calculations and controls.

The communication circuit 199 is a communication interface that is connected to a communication device (not shown) and other ECUs so that data can be transmitted and received.

<1. First Embodiment>
Next, the first embodiment of the present invention will be described with reference to FIGS. 4 to 13. First, the valve lift curves of the two intake valves 6a and 6b will be described with reference to FIG.

[Valve lift curve]
FIG. 4 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and the crank angle of the two intake valves 6a and 6b according to the first embodiment. The horizontal axis of FIG. 4 represents the crank angle, and the vertical axis represents the valve lift amount.

Conventionally, as shown by the broken line, the valve lift curve Cn of the intake valve reaches the maximum value approximately at the center of the valve opening start time and the valve closing end time suitable for intake into the cylinder 1. It has a symmetrical shape. When two intake valves are provided, the two intake valves operate on the same valve lift curve Cn. During the intake period from the start of valve opening to the end of valve closing, the intake valves 6a and 6b are opened and air is sucked into the cylinder 1.

In the present embodiment, the intake valve drive device 8a matches the valve opening start timing and valve closing end timing of the intake valve 6a with the valve opening start timing and valve closing end timing of the intake valve 6b, and the valve lift of the intake valve 6a. The valve timing (crank angle Pa) that maximizes the amount is advanced more than usual so that the valve lift curve C6a is asymmetrical. Similarly, the intake valve drive device 8b matches the valve opening start timing and valve closing end timing of the intake valve 6b with the valve opening start timing and valve closing end timing of the intake valve 6a, and the valve lift amount of the intake valve 6b is increased. The maximum valve timing (crank angle Pb) is retarded more than usual so that the valve lift curve C6b is asymmetrical. That is, the phase difference Dp is set at the valve timing (crank angles Pa, Pb) at which the valve lift amount of the intake valves 6a and 6b is maximized without changing the valve opening start timing and the valve closing end timing of the intake valves 6a and 6b. Is giving.

Looking at the rate of change in the valve lift amount of the intake valves 6a and 6b, for the intake valve 6a, the rate of change in the valve lift amount until the maximum valve lift amount is large, and after the peak until the valve is closed. The rate of change in the valve lift amount is small. Regarding the rate of change in the valve lift amount of the intake valve 6b, the rate of change in the valve lift amount until the valve lift amount is maximized is smaller than that in the case of the intake valve 6b, and after the peak until the valve is closed. The rate of change in the valve lift amount is large.

As described above, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU193) determines the rate of change in the lift amount until the lift amount of the first intake valve (crank angle Pa) reaches its peak. It is configured to control the rate of change of the lift amount until the lift amount of the second intake valve (crank angle Pb) reaches the peak.

According to the valve control device according to the present embodiment configured as described above, the timing at which the lift amount of the first intake valve reaches the peak and the timing at which the lift amount of the second intake valve reaches the peak can be freely controlled. can do. Therefore, according to the valve control device according to the present embodiment, the timing at which the lift amount of the first intake valve reaches the peak and the timing at which the lift amount of the second intake valve reaches the peak are different (phase difference Dp). Can be provided). Then, the timing at which the lift amounts of the two intake valves reach their peaks differs during one cycle (intake period), so that the magnitude relationship between the lift amounts of the two intake valves is reversed at least once (once in FIG. 4). , It becomes possible to reverse the rotation direction of the swirl in the combustion chamber 12.

[Change in swirl direction]
FIG. 5 is a schematic view showing a change in the direction of the swirl in the combustion chamber 12 when the intake valves 6a and 6b are operated according to the valve lift curve of FIG. The swirl is a vortex (lateral vortex) of an air flow generated in a direction perpendicular to the driving direction of the piston. The number of arrows represents the magnitude of the flow rate.

By setting the valve lift curves C6a and C6b as described above, as shown in the upper part of FIG. 5, the intake valve 6a is first opened wider than the intake valve 6b, and the air flowing from the intake valve 6a side is opened. The flow rate of is increased. Therefore, a clockwise swirl SWa is formed in the combustion chamber 12 due to the flow rate difference.

After that, as shown in the lower part of FIG. 5, on the contrary, the intake valve 6b is opened wider than the intake valve 6a, and this time, the flow rate of the air flowing from the intake valve 6b side increases. Therefore, a counterclockwise swirl SWb is formed in the combustion chamber 12 due to the flow rate difference. That is, the rotation direction of the swirl generated in the combustion chamber 12 is reversed in the middle of the intake stroke.

[simulation result]
The results of simulating this embodiment by CFD (Computational Fluid Dynamics) will be described below.

(Change in swirl ratio)
FIG. 6 is a simulation result showing a change in the swirl ratio in the first embodiment. The horizontal axis of FIG. 6 represents the crank angle [° bTDC], and the vertical axis represents the swirl ratio. The swirl ratio is expressed as the ratio of the rotation speed of the swirl to the rotation speed of the engine.

When there is no phase difference in the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximized, air flows into the cylinder from the left and right intake valves 6a and 6b in the same manner, and there is no bias, so it is shown by a broken line. No swirl occurs. On the other hand, when there is a phase difference in the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximized, as shown by the solid line, the swirl ratio of minus (clockwise direction shown in FIG. 5) is first introduced. It has become. After that, the swirl ratio changes to plus (counterclockwise direction shown in FIG. 5), indicating that the swirl rotation direction is reversed in the middle.

(Change in tumble ratio)
FIG. 7 is a simulation result showing a change in the tumble ratio in the first embodiment. The horizontal axis of FIG. 7 represents the crank angle [° bTDC], and the vertical axis represents the tumble ratio. The tumble is a vertical vortex generated in the combustion chamber 12. The tumble ratio is expressed as the ratio of the rotation speed of the tumble to the rotation speed of the engine.

It is shown that when there is a phase difference in the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximized, the tumble is stronger than when there is no phase difference. When there is no phase difference due to collision of the intake air sucked from the intake valves 6a and 6b from the start of valve opening to the vicinity of the valve timing (crank angle Pr) where the valve lift amounts of the intake valves 6a and 6b are reversed. The tumble (broken line) of is stronger than the tumble (solid line) when there is a phase difference. After that, when the valve lift amounts of the intake valves 6a and 6b are reversed, the rotation direction of the swirl is reversed and the flow is turbulent. That is, when the valve lift amount is reversed, a part of the lateral flow shifts to the diagonal direction or the vertical direction. Therefore, as the piston 3 approaches the top dead center from the time when the valve lift amount is reversed, the strength of the tumble when there is no phase difference decreases, but the tumble when there is a phase difference maintains a higher strength. ..

(Changes in kinetic energy of turbulence)
FIG. 8 is a simulation result showing a change in the kinetic energy of the turbulent flow in the cylinder in the first embodiment. The horizontal axis of FIG. 8 represents the crank angle [° bTDC], and the vertical axis represents the turbulent kinetic energy [mJ].
When there is a phase difference in the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximized, the flow is turbulent when the rotation direction of the swirl shown in FIG. 6 is reversed as compared with the case where there is no phase difference. Has been shown to increase the subsequent turbulent kinetic energy.

(Change in kinetic energy of average flow)
FIG. 9 is a simulation result showing a change in the kinetic energy of the average flow in the first embodiment. The horizontal axis of FIG. 9 represents the crank angle [° bTDC], and the vertical axis represents the turbulent kinetic energy [mJ].
Similar to the turbulent kinetic energy shown in FIG. 8, when there is a phase difference in the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximized, it is shown in FIG. 6 as compared with the case where there is no phase difference. It is shown that the kinetic energy of the average flow increases after the rotation direction of the swirl is reversed.

As shown from the above simulation results, one intake valve advances the valve timing at which the valve lift amount is maximized without changing the valve opening start timing and valve closing end timing of the two intake valves 6a and 6b. It is preferable to control the operation of the two intake valves 6a and 6b so that the other intake valve on the corner side is shifted to the retard side. By providing a phase difference at the timing when the valve lift amount of the two intake valves 6a and 6b is maximized, a difference occurs in the flow rate of air from the two intake valves 6a and 6b, a swirl is generated, and the rotation thereof. The direction is reversed in the middle, and as a result, the in-cylinder flow is strengthened. By strengthening the in-cylinder flow, the EGR (Exhaust Gas Recirculation) limit and the lean limit are improved, and the combustion performance of the engine 100 can be improved.

[Valve timing phase difference and sensitivity]
Further, a sensitivity analysis was performed using the phase difference of the valve timing at which the valve lift amount of the two intake valves 6a and 6b is maximized as a parameter, and the results are shown below.

(Swirl ratio sensitivity analysis result)
FIG. 10 is a simulation result of analyzing the sensitivity of the swirl ratio with respect to the phase difference of the valve timing at which the valve lift amount of the two intake valves 6a and 6b in the first embodiment is maximized. The horizontal axis of FIG. 10 represents the crank angle [° bTDC], and the vertical axis represents the swirl ratio. Here, the change in the swirl ratio in the cylinder 1 when the phase difference of the valve timing at which the valve lift amount is maximized is set to 40 degrees, 60 degrees, 80 degrees, 100 degrees, and 120 degrees as the crank angle is compared. is doing.

In FIG. 10, the value of the swirl ratio changes from negative to positive from the start of opening the two intake valves to the end of closing the two intake valves regardless of the crank angle, and the rotation of the swirl. It is shown that the direction is reversed in the middle. The magnitude of the swirl ratio after the value of the swirl ratio changes from negative to positive increases according to the phase difference of the valve timing at which the valve lift amount is maximized.

However, regarding the magnitude of the absolute value of the swirl ratio in the negative direction that first occurs immediately after the start of valve opening, there are cases where the phase difference is from 40 degrees to 100 degrees and cases where the phase difference is from 100 degrees to 120 degrees. The amount of increase in the absolute value of the swirl ratio is different. That is, when the phase difference is 100 degrees or more, the sensitivity of the swirl ratio immediately after the valve start becomes high, and there is a big difference in the swirl ratio level between the case where the phase difference is 80 degrees or less and the case where the phase difference is 100 degrees or more. Can be seen. Although not shown, when the phase difference is 140 degrees, there is no increase in the absolute value of the swirl ratio in the negative direction that occurs first at 40 degrees, 60 degrees, and 80 degrees, and when it is 120 degrees. It was only slightly larger than. Therefore, it can be said that the valve timing difference (phase difference) at which the valve lift amount of the two intake valves 6a and 6b is maximized is preferably 100 degrees or more.

In this way, by setting the valve timing phase difference to 100 degrees or more, the difference in the strength of the swirl that reverses can be made larger than when the valve timing phase difference is less than 100 degrees, and the in-cylinder flow can be increased. Can be further strengthened.

(Results of tumble ratio sensitivity analysis)
FIG. 11 is a simulation result of analyzing the sensitivity of the tumble ratio with respect to the phase difference of the valve timing at which the valve lift amount of the two intake valves 6a and 6b in the first embodiment is maximized. The horizontal axis of FIG. 11 represents the crank angle [° bTDC], and the vertical axis represents the tumble ratio. Here, the change in the tumble ratio in the cylinder 1 when the phase difference of the valve timing at which the valve lift amount is maximized is set to 80 degrees, 100 degrees, and 120 degrees as the crank angle is compared.

FIG. 11 shows that the larger the phase difference between the valve timings at which the valve lift amounts of the two intake valves 6a and 6b are maximized, the stronger the tumble as a whole. Although not shown, the same tendency was observed even when the valve timing phase difference was 40 degrees, 60 degrees, or 140 degrees.

(Results of sensitivity analysis of turbulent kinetic energy)
FIG. 12 is a simulation result of analyzing the sensitivity of the kinetic energy of the turbulent flow in the cylinder 1 to the phase difference of the valve timing at which the valve lift amount of the two intake valves 6a and 6b in the first embodiment is maximized. .. The horizontal axis of FIG. 12 represents the crank angle [° bTDC], and the vertical axis represents the turbulent kinetic energy [mJ].

In FIG. 12, a difference is seen in the turbulent kinetic energy from the timing after the rotation direction of the swirl shown in FIG. 10 is reversed, and the phase difference of the valve timing at which the valve lift amounts of the two intake valves 6a and 6b are maximized. It has been shown that the larger the value, the greater the turbulent kinetic energy. Although not shown, the same tendency was observed even when the valve timing phase difference was 40 degrees, 60 degrees, or 140 degrees.

(Results of sensitivity analysis of kinetic energy of average flow)
FIG. 13 is a simulation result of analyzing the sensitivity of the kinetic energy of the average flow to the phase difference of the valve timing at which the valve lift amounts of the two intake valves 6a and 6b in the first embodiment are maximized. The horizontal axis of FIG. 13 represents the crank angle [° bTDC], and the vertical axis represents the turbulent kinetic energy [mJ] of the average flow.

Also in FIG. 13, as in the case of the turbulent kinetic energy, there is a difference in the kinetic energy of the average flow from the timing after the rotation method of the swirl shown in FIG. 10 is reversed. That is, FIG. 13 shows that the larger the phase difference between the valve timings at which the valve lift amounts of the two intake valves 6a and 6b are maximized, the larger the kinetic energy of the average flow. Although not shown, the same tendency was observed even when the valve timing phase difference was 40 degrees, 60 degrees, or 140 degrees.

As described above, the valve control device (ECU 20) according to the first embodiment includes the first intake valve (intake valve 6a) and the first intake valve (intake valve 6a) provided in the intake port communicating with the inside of the cylinder (combustion chamber 12) of the internal combustion engine. It is a valve control device that controls the opening / closing drive of the second intake valve (intake valve 6b), and the lift amount of the first intake valve and the lift amount of the second intake valve are large or small during one cycle of the internal combustion engine. A control device (CPU193) for controlling the lift amount of the first intake valve and the lift amount of the second intake valve is provided so that the relationship is reversed at least once.

According to the valve control device according to the first embodiment configured as described above, the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve is reversed at least once. The rotation direction of the swirl generated in the cylinder due to the difference in opening between the two intake valves can be reversed in the middle of the intake operation. As a result, it becomes possible to further strengthen the in-cylinder flow.

Further, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU193) has a timing (crank angle Pa) at which the lift amount of the first intake valve (intake valve 6a) reaches a peak and a second. The timing (crank angle Pb) at which the lift amount of the intake valve (intake valve 6b) reaches its peak is controlled to be different.

According to the valve control device according to the present embodiment configured as described above, the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve can be reversed at least once.

Further, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU193) has a timing (crank angle Pa) at which the lift amount of the first intake valve (intake valve 6a) reaches a peak and a second. The difference from the timing (crank angle Pb) at which the lift amount of the intake valve (intake valve 6a) reaches its peak is controlled so that the crank angle is 100 degrees or more.

According to the valve control device according to the present embodiment configured in this way, by setting the phase difference at the timing when the lift amount of the two intake valves reaches the peak to 100 degrees or more, the swirl before and after the rotation direction is reversed. The difference in strength can be made larger. Then, by increasing the difference in the strength of the swirl that reverses, it becomes possible to further strengthen the in-cylinder flow.

Further, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU193) starts valve opening between the first intake valve (crank angle Pa) and the second intake valve (crank angle Pb). It is configured to control the opening / closing drive of the first intake valve and the second intake valve by matching the timing and the valve opening end timing, respectively.

According to the valve control device according to the present embodiment configured in this way, the opening / closing drive of the two intake valves is controlled by matching the valve opening start timing and the valve opening end timing between the two intake valves. It is possible to further enhance the in-cylinder flow rate while inhaling in a pre-designed optimum period.

<2. Second embodiment>
Next, the operation of the two intake valves 6a and 6b according to the second embodiment of the present invention will be described with reference to FIG. Also in this embodiment, the engine 100 shown in FIG. 1 is targeted.

FIG. 14 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and the crank angle of the two intake valves 6a and 6b according to the second embodiment. The horizontal axis of FIG. 14 represents the crank angle, and the vertical axis represents the valve lift amount.

In FIG. 4 described above, the valve lift amount gradually decreases after the valve lift amount of the intake valve 6a becomes maximum, but as shown in FIG. 14, the valve lift amount is approximately in the middle of the decrease in the valve lift amount. You may give a period to be constant. Similarly, in FIG. 4, the valve lift amount gradually increases until the valve lift amount of the intake valve 6b reaches the maximum value, but as shown in FIG. 14, the valve is in the middle of increasing the valve lift amount. A period may be given in which the lift amount becomes substantially constant.

In this way, even by providing a period in which the valve lift amount is maintained constant in the middle of the valve lift, it is possible to form a left-right asymmetric valve lift curve centered on the center of the valve opening start time and valve opening end time. can. Therefore, it is possible to give a phase difference to the valve timing at which the valve lift amounts of the two intake valves 6a and 6b are maximized. As a result, a swirl is generated in the combustion chamber 12 due to the difference in opening degree between the intake valves 6a and 6b, and the rotation direction thereof is reversed in the middle, so that the in-cylinder flow can be further strengthened.

<3. Third Embodiment>
Next, the operation of the two intake valves 6a and 6b according to the third embodiment of the present invention will be described with reference to FIG. Also in this embodiment, the engine 100 shown in FIG. 1 is targeted.

FIG. 15 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and the crank angle of the two intake valves 6a and 6b according to the third embodiment. The horizontal axis of FIG. 15 represents the crank angle, and the vertical axis represents the valve lift amount.

In the first and second embodiments described above (see FIGS. 4 and 14), the maximum values of the valve lift amounts of the intake valves 6a and 6b are the same, but as shown in FIG. 15, the intake valves 6a and 6b are the same. It is also possible to change the maximum value of the valve lift amount of. That is, in the valve control device (ECU 20) according to the third embodiment, the control device (CPU193) has a peak value of the lift amount of the first intake valve (crank angle Pa) and a second intake valve (crank angle). The peak value of the lift amount of Pb) is controlled respectively. FIG. 15 shows an example in which the peak value of the valve lift curve C6b of the intake valve 6b is larger than the peak value of the valve lift curve C6a of the intake valve 6a. The valve timing phase difference Dp at which the valve lift amount of the intake valves 6a and 6b peaks is the same as the phase difference Dp in FIG.

As described in the first and second embodiments described above, the difference in opening between the intake valves 6a and 6b at the valve timing at which the valve lift amount is maximized affects the strength of the swirl (in-cylinder flow). Further, as shown in FIG. 15, by changing the peak value of the valve lift amount of the intake valves 6a and 6b, the difference in opening degree between the intake valves 6a and 6b is changed, and the strength of the generated swirl is controlled. Will be possible.

For example, in the example shown in FIG. 15, after the valve timing (crank angle Pr) in which the valve lift amounts of the intake valves 6a and 6b are reversed, the difference in opening between the intake valves 6a and 6b becomes large, and the strength of the swirl increases. Further, the valve timing (crank angle Pr) at which the valve lift amounts of the intake valves 6a and 6b are reversed is compared with the valve timing of the first and second embodiments (the same as the valve timing at which the valve lift curve Cn peaks). Then, it changes to the advance angle side. In this way, by advancing the valve timing at which the valve lift amounts of the two intake valves are reversed, the strength of the swirl at the ignition / combustion timing is increased as compared with the case where the valve timing is not advanced, and the in-cylinder flow. Is further strengthened.

In FIG. 15, the valve timing (crank angle Pr) at which the valve lift amounts of the intake valves 6a and 6b are reversed is changed to the advance angle side with respect to the valve timing at which the valve lift curve Cn peaks. It does not rule out that the valve timing changes to the retard side.

<4. Fourth Embodiment>
Next, the operation of the two intake valves 6a and 6b according to the fourth embodiment of the present invention will be described with reference to FIG. Also in this embodiment, the engine 100 shown in FIG. 1 is targeted.

FIG. 16 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount of the intake valve and the crank angle according to the fourth embodiment. The horizontal axis of FIG. 16 represents the crank angle, and the vertical axis represents the valve lift amount.

In FIG. 16, the maximum value of the valve lift amount of the intake valves 6a and 6b is the same, but the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximum is the valve of the first and second embodiments. It is on the advance side as compared with the timing (valve timing at which the valve lift curve Cn peaks). That is, in FIG. 16, the valve timing (crank angle Pr) in which the valve lift amounts of the two intake valves 6a and 6b are reversed is changed to the advance angle side with respect to the valve timings of the first and second embodiments. ..

The fourth embodiment configured in this way does not advance the valve timing as in the third embodiment by advancing the valve timing at which the valve lift amounts of the two intake valves reverse. It is possible to increase the strength of the swirl at the ignition / combustion timing as compared with the case. As a result, the in-cylinder flow is further strengthened.

In FIG. 16, the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximized is on the advance side with respect to the valve timing at which the valve lift curve Cn peaks, but the present invention is not limited to this example. That is, the difference between the valve timing that is the peak of the valve lift curve C6a and the valve lift curve Cn may be controlled to be larger than the difference between the valve timing that is the peak of the valve lift curve C6b and the valve lift curve Cn.

In FIG. 16, the valve timing (crank angles Pr, Pb) at which the valve lift amounts of the intake valves 6a and 6b peak is changed to the advance side with respect to the valve timing of the peak of the valve lift curve Cn. , It does not exclude that the valve timing changes to the retard side.

<5. Fifth Embodiment>
Next, the operation of the two intake valves 6a and 6b according to the fifth embodiment of the present invention will be described with reference to FIGS. 17 and 18. Also in this embodiment, the engine 100 shown in FIG. 1 is targeted.

[Valve lift curve]
FIG. 17 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and the crank angle of the two intake valves 6a and 6b according to the fifth embodiment. The horizontal axis of FIG. 17 represents the crank angle, and the vertical axis represents the valve lift amount.

In FIG. 17, the intake valve 6a opens and closes the valve once in one cycle, and the intake valve 6b opens and closes the valve twice in one cycle. The CPU 193 of the ECU 20 matches the first valve opening start timing of the intake valve 6a with the first valve opening start timing of the intake valve 6b, and the valve closing end timing of the intake valve 6a and the second closing timing of the intake valve 6b. Match with the valve end timing. The peak value of the valve lift amount of the intake valve 6a is larger than the valve lift amount of the intake valve 6b at the valve timing at which the peak value is reached. Further, the two peak values of the valve lift amount of the intake valve 6b are larger than the valve lift amount of the intake valve 6a at the valve timing at which the peak values are obtained.

Although FIG. 17 shows an example in which the peak value of the valve lift amount of the intake valve 6a is larger than the peak value of the valve lift amount of the intake valve 6b, the valve lift amount of the intake valves 6a and 6b is shown. The peak values may be the same. Further, the two peak values of the valve lift amount of the intake valve 6b may be different values. Further, the intake valve 6b is completely closed (the valve lift amount becomes 0) by the first on-off valve operation, and then the second on-off valve operation is performed, but before the valve is completely closed, 2 The on-off valve operation for the second time may be performed.

[Change in swirl direction]
FIG. 18 is a schematic view showing a change in the direction of the swirl in the combustion chamber 12 when the intake valves 6a and 6b are operated according to the valve lift curve of FIG.
Looking at it over time as shown in FIG. 18, first, since the valve lift amount of the intake valve 6b is larger than the valve lift amount of the intake valve 6a, the flow rate of the air entering from the intake valve 6b is large, and the inside of the combustion chamber 12 A counterclockwise swirl SWb is formed in (upper part of FIG. 18). Next, the valve lift amount of the intake valve 6a becomes large, the valve lift amount of the intake valve 6b becomes small, the flow rate of air from the intake valve 6a increases, and conversely, a clockwise swirl SWa is formed ( (Middle of FIG. 18). Further, when the valve lift amount of the intake valve 6b becomes larger than the valve lift amount of the intake valve 6a again, the flow rate of air from the intake valve 6b increases, and the force for forming the counterclockwise swirl SWb again increases. It works (lower part of Fig. 18).

That is, the difference in opening degree between the two intake valves 6a and 6b can be changed with time by making the number of times the two intake valves 6a and 6b open different. Then, by changing the direction of the generated swirl, it becomes possible to increase the turbulence of the air in the cylinder 1 and strengthen the in-cylinder flow.

As described above, in the valve control device (ECU 20) according to the fifth embodiment, the first intake valve (intake valve 6a) opens and closes once in one cycle, and the second intake valve (intake valve 6b). Is set to operate the on-off valve twice in one cycle. Then, in the control device (CPU193), the peak value of the lift amount of the first intake valve is larger than the lift amount of the second intake valve at the peak timing, and the lift amount of the second intake valve is 1 The peak values of the first and second peaks are controlled to be larger than the lift amount of the first intake valve at the peak timing.

In the fifth embodiment configured in this way, the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve can be reversed twice. As a result, the rotation direction of the swirl generated in the cylinder due to the difference in opening of the two intake valves is reversed twice in the middle of the intake operation, causing a more complicated air flow than in the case of one reverse rotation, and further in the cylinder. It becomes possible to strengthen the flow.

<Modified example of the fifth embodiment>
In the fifth embodiment described above, when the intake valve 6b opens and closes the valve twice in one cycle, the valve is opened and closed twice in succession, but other operations may be used.

FIG. 19 is another operating characteristic curve diagram (valve lift curve) of the two intake valves 6a and 6b in the fifth embodiment (see FIG. 17). The horizontal axis of FIG. 19 represents the crank angle, and the vertical axis represents the valve lift amount.
As shown in FIG. 19, a rest period Ti is provided between the first valve closing end timing and the second valve opening start timing of the intake valve 6b, and the first on-off valve operation and the second opening / closing valve operation of the intake valve 6b are provided. It is configured to widen the interval between on-off valve operations. Even with such a configuration, the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve can be reversed twice, so that the in-cylinder flow is further increased than in the case of one reverse rotation. Can be strengthened.

<6. Sixth Embodiment>
Next, the operation of the two intake valves 6a and 6b according to the sixth embodiment of the present invention will be described with reference to FIG. Also in this embodiment, the engine 100 shown in FIG. 1 is targeted.

FIG. 20 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount of the intake valve and the crank angle according to the sixth embodiment. The horizontal axis of FIG. 20 represents the crank angle, and the vertical axis represents the valve lift amount.

The valve lift curve C6a of the intake valve 6a has a maximum (peak) valve lift amount at the center (crank angle Pa) of the valve lift curve C6a and has a substantially triangular shape. On the other hand, the valve lift curve C6b of the intake valve 6b has a larger rate of change between rising and falling than the valve lift curve C6a of the intake valve 6a, and has a period (flat portion) in which the maximum value is maintained. It has a shape. In this example, the valve timing in the middle of the period in which the maximum value of the valve lift curve C6b is maintained is the crank angle Pb, which is the same as the crank angle Pa, but may be different from the crank angle Pa.

Here, the peak value of the valve lift amount of the intake valve 6a is larger than the maximum value of the valve lift amount of the intake valve 6b. Further, during the period in which the maximum value of the valve lift curve C6b is maintained, the peak value of the valve lift amount of the intake valve 6a is larger than the maximum value of the valve lift amount of the intake valve 6b on both sides (advance angle side) of T1. In the period T2 on the retard side), the maximum value of the valve lift amount of the intake valve 6b is larger than the valve lift amount of the intake valve 6a. Further, the valve opening start timing and the valve closing end timing of the intake valve 6a and the intake valve 6b are the same.

Therefore, the opening amount of the intake valve 6b is larger than the opening amount of the intake valve 6a at first, and then the valve opening amount of the intake valve 6a is larger in the vicinity where the valve lift amount of the intake valve 6a is maximum. It becomes larger than the valve opening amount of the intake valve 6b. After that, the valve opening amount of the intake valve 6b becomes larger than the valve opening amount of the intake valve 6a again.

Therefore, also in this embodiment, as shown in FIG. 18, since the flow rate of air from the intake valve 6b is large at the beginning after the valve opening is started, a counterclockwise swirl SWb is formed in the combustion chamber 12, and then. On the contrary, a clockwise swirl SWa is induced by increasing the flow rate of air from the intake valve 6a, and then a counterclockwise swirl SWb is formed again by increasing the flow rate of the intake air from the intake valve 6b. become. Even if the two intake valves 6a and 6b are symmetrical valve lift curves C6a and C6b, the flow rate differs due to the difference in the valve lift amount, and the direction of the swirl formed in the combustion chamber 12 is changed. It will be reversed twice.

As described above, in the valve control device (ECU 20) according to the sixth embodiment, the first intake valve (intake valve 6a) and the second intake valve (intake valve 6b) operate the on-off valve once in one cycle. It is set to do. Then, the control device (CPU193) maintains a state in which the lift amount of the second intake valve reaches the peak for a certain period of time, and the timing (crank angle) when the lift amount of the first intake valve reaches the peak within a certain period of time. In the first period (period T1) including Pa), the lift amount of the first intake valve is larger than the lift amount of the second intake valve, and the advance angle is larger than the first period within a certain period. In the second period (period T2) on the side and the retard side, the lift amount of the second intake valve is controlled to be larger than the lift amount of the first intake valve.

In the sixth embodiment configured in this way, the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve is 2 while the valve open state of the second intake valve is maintained. It can be reversed once. As a result, the rotation direction of the swirl generated in the cylinder due to the difference in opening of the two intake valves is reversed twice in the middle of the intake operation, causing a more complicated air flow than in the case of one reverse rotation, and further in the cylinder. It becomes possible to strengthen the flow.

<7. Seventh Embodiment>
Next, the operation of the two intake valves 6a and 6b according to the seventh embodiment of the present invention will be described with reference to FIG. Also in this embodiment, the engine 100 shown in FIG. 1 is targeted.

In the present embodiment, the timings of valve opening start and valve closing end of the intake valves 6a and 6b are matched, and the valve lift curves of the intake valves 6a and 6b each have a plurality of peaks, and the phases at which the peaks are reached. Are offset from each other. That is, in the vicinity of a plurality of peaks of the valve lift amount of the intake valve 6a, the valve lift amount of the intake valve 6a is larger than the valve lift amount of the intake valve 6b. On the contrary, in the vicinity of a plurality of peaks of the valve lift amount of the intake valve 6b, the valve lift amount of the intake valve 6b is larger than the valve lift amount of the intake valve 6a.

FIG. 21 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount of the intake valve and the crank angle according to the seventh embodiment. The horizontal axis of FIG. 21 represents the crank angle, and the vertical axis represents the valve lift amount.

As shown in FIG. 21, since the valve lift curves C6a and C6b of the intake valves 6a and 6b each have two peaks, a state in which the magnitude relation of the valve lift amounts of the intake valves 6a and 6b is different occurs four times in total. The larger the lift amount of the intake valve, the larger the flow rate of the air flowing into the combustion chamber 12, which causes a swirl in the combustion chamber 12. Therefore, every time the valve lift amount is changed, a flow in the opposite direction is caused. Therefore, according to the valve lift curves C6a and C6b, the action of reversing the rotation direction of the swirl three times works, and a more complicated flow is generated, so that the in-cylinder flow is strengthened.

Although the case where the valve lift curves C6a and C6b of the intake valves 6a and 6b each have two peaks has been described, the number of peaks of the valve lift curves of the intake valves 6a and 6b may be three or more. Further, the intake valves 6a and 6b perform the second on-off valve operation before the valve is completely closed by the first on-off valve operation (the valve lift amount becomes 0), but the valve is completely closed once. Then, the on-off valve operation may be performed for the second time.

As described above, in the valve control device (ECU 20) according to the seventh embodiment, the first intake valve (intake valve 6a) and the second intake valve (intake valve 6b) operate the on-off valve a plurality of times in one cycle. It is set to do. Then, in the control device (CPU193), the plurality of peak values of the lift amount of the first intake valve are larger than the lift amount of the second intake valve at the peak timing, and the lift amount of the second intake valve is large. The plurality of peak values of the above are controlled to be larger than the lift amount of the first intake valve at the peak timing.

In the seventh embodiment configured in this way, a plurality of magnitude relations between the lift amount of the first intake valve and the lift amount of the second intake valve are set in a state where the valve open state of the second intake valve is maintained. It can be reversed once. The number of reversals is the sum of the peak numbers of the valve lift amounts of the two intake valves. As a result, the rotation direction of the swirl generated in the cylinder due to the difference in the opening degree of the two intake valves is reversed multiple times in the middle of the intake operation, causing a more complicated air flow than in the case of reversing once and twice. Furthermore, it becomes possible to strengthen the in-cylinder flow.

<8. Eighth Embodiment>
In the first to seventh embodiments described above, by matching the timings of the valve opening start and valve closing ends of the intake valves 6a and 6b, the timing may not be changed from the optimum timing for the intake and exhaust designed in advance. desirable. However, it is also possible to make the timings of the valve opening start and the valve closing end of the intake valves 6a and 6b different from each other. Even in this case, by giving a phase difference to the valve timing at which the valve lift amount of the intake valves 6a and 6b becomes the maximum value (peak), an opening difference occurs between the intake valve 6a and the intake valve 6b, and a swirl occurs. Moreover, the magnitudes of the opening degrees of the intake valve 6a and the intake valve 6b are switched. Then, the direction of the swirl generated in the combustion chamber 12 is reversed, and the in-cylinder flow is strengthened. By strengthening the in-cylinder flow, the EGR limit and the lean limit are improved, and the combustion performance of the engine 100 can be improved.

<9. Ninth Embodiment>
Next, as a ninth embodiment of the present invention, first and second examples in which the peaks of the valve lift curves of the two intake valves 6a and 6b coincide with each other will be described with reference to FIGS. 22 and 23.

[First example]
FIG. 22 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount of the intake valve and the crank angle according to the first example of the ninth embodiment. The horizontal axis of FIG. 22 represents the crank angle, and the vertical axis represents the valve lift amount.

In FIG. 22, the valve lift curve C6a of the intake valve 6a peaks at the crank angle Pa. Further, the valve lift curve C6b of the intake valve 6b peaks at the same crank angle Pb as the crank angle Pa. That is, the intake valves 6a and 6b have the same valve timing at which the valve lift amount is maximized. However, the maximum value (peak value) of the valve lift amount of the intake valve 6a is larger than the maximum value (peak value) of the valve lift amount of the intake valve 6b.

Further, the valve lift curve C6a is symmetrical about the valve timing (crank angle Pa) at which the peak is generally reached, but the valve lift curve C6b is closed after the peak rather than the rate of change of the valve lift amount until the peak. The rate of change in the valve lift amount until valve is small. From another viewpoint, the valve opening start timing of the intake valve 6a is the same as the valve opening start timing of the intake valve 6b, but the valve closing end timing of the intake valve 6a is earlier than the valve closing end timing of the intake valve 6b. ..

[Second example]
FIG. 23 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount of the intake valve and the crank angle according to the second example of the ninth embodiment. The horizontal axis of FIG. 23 represents the crank angle, and the vertical axis represents the valve lift amount.

In FIG. 23, the valve lift curve C6a of the intake valve 6a peaks at the crank angle Pa. Further, the valve lift curve C6b of the intake valve 6b peaks at the same crank angle Pb as the crank angle Pa. That is, the intake valves 6a and 6b have the same valve timing at which the valve lift amount becomes maximum (peak). However, the maximum value (peak value) of the valve lift amount of the intake valve 6a is larger than the maximum value (peak value) of the valve lift amount of the intake valve 6b.

Furthermore, the valve lift curves C6a and C6b are symmetrical with respect to the valve timing (crank angles Pa and Pb) at which the peak is generally reached. However, the rate of change in the valve lift amount until the valve lift curve C6a reaches its peak and the rate of change in the valve lift amount after the peak until the valve closes are the valve lift amounts until the valve lift curve C6b reaches its peak, respectively. It is larger than the rate of change of the valve lift and the rate of change of the valve lift amount after the peak until the valve is closed. From another viewpoint, the valve opening start timing of the intake valve 6a is later than the valve opening start timing of the intake valve 6b, and the valve closing end timing of the intake valve 6a is earlier than the valve closing end timing of the intake valve 6b.

As described above, in the valve control device (ECU 20) according to the ninth embodiment, the control device (CPU193) has a timing at which the lift amount of the first intake valve (intake valve 6a) reaches a peak and a second intake. The timing (crank angle Pa, Pb) at which the lift amount of the valve (intake valve 6b) reaches its peak is adjusted, and the peak value of the lift amount of the first intake valve and the peak value of the lift amount of the second intake valve are set. The first intake valve and the second intake valve are different so that at least one of the valve opening start timing and the valve opening end timing is shifted between the first intake valve and the second intake valve. Controls open / close drive.

In the present embodiment configured as described above, even when the valve timing at which the lift amount of the first intake valve and the second intake valve peaks is matched, the opening difference between the two intake valves occurs. It is possible to generate a swirl in the cylinder. Further, in the present embodiment, since the sizes of the opening degrees of the two intake valves can be exchanged, the direction of the swirl is reversed and the in-cylinder flow is further strengthened.

Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that various other application examples and modifications can be taken as long as they do not deviate from the gist of the present invention described in the claims.
For example, each of the above-described embodiments describes the valve control of the engine control unit (valve control device) in detail and concretely in order to explain the present invention in an easy-to-understand manner, and necessarily includes all the components described above. Not limited to. Further, it is possible to replace a part of the configuration of one embodiment with a component of another embodiment. It is also possible to add components of another embodiment to the configuration of one embodiment. It is also possible to add, replace, or delete other components with respect to a part of the configuration of each embodiment.

Further, each of the above configurations, functions, processing units, etc. may be realized by hardware by designing a part or all of them by, for example, an integrated circuit. As the hardware, a processor device in a broad sense such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) may be used.

1 ... Cylinder, 2 ... Cylinder head, 3 ... Piston, 4 ... Intake port, 5 ... Exhaust port, 6a, 6b ... Intake valve, 7a, 7b ... Exhaust valve, 8a, 8b ... Intake valve drive device, 9a, 9b ... Exhaust valve drive device, 10 ... fuel injection valve, 11 ... ignition plug, 12 ... combustion chamber, 14 ... crank angle sensor, 20 ... ECU (valve control device), 100 ... engine, 193 ... CPU (control device), C6a, C6b ... Valve lift curve, Pa, Pb ... Cylinder angle at which the valve lift amount peaks

Claims (11)

1. A valve control device for controlling the opening / closing drive of the first intake valve and the second intake valve, which are provided in the intake port communicating with the inside of the cylinder of the internal combustion engine.
   The lift amount of the first intake valve and the lift amount of the first intake valve are reversed so that the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve is reversed at least once during one cycle of the internal combustion engine. A valve control device including a control device for controlling the lift amount of the second intake valve.
2. The valve control device according to claim 1, wherein the control device controls so that the timing at which the lift amount of the first intake valve reaches its peak and the timing at which the lift amount of the second intake valve reaches its peak are different. ..
3. In the control device, the difference between the timing when the lift amount of the first intake valve reaches the peak and the timing when the lift amount of the second intake valve reaches the peak is 100 degrees or more in terms of the crank angle. The valve control device according to claim 2.
4. The control device determines the rate of change of the lift amount until the lift amount of the first intake valve reaches the peak and the rate of change of the lift amount until the lift amount of the second intake valve reaches the peak. The valve control device according to claim 2, which controls each.
5. The valve control device according to claim 2, wherein the control device controls the peak value of the lift amount of the first intake valve and the peak value of the lift amount of the second intake valve.
6. The control device opens and closes the first intake valve and the second intake valve by matching the valve opening start timing and the valve opening end timing between the first intake valve and the second intake valve. The valve control device according to claim 1, wherein the drive is controlled.
7. The first intake valve is set to operate the on-off valve once in one cycle, and the second intake valve is set to operate the on-off valve twice in one cycle.
   In the control device, the peak value of the lift amount of the first intake valve is larger than the lift amount of the second intake valve at the peak timing, and the lift amount of the second intake valve is the first time. The valve control device according to claim 1, wherein the second peak value is controlled to be larger than the lift amount of the first intake valve at the peak timing.
8. The first intake valve and the second intake valve are set to operate the on-off valve once in one cycle.
   The control device maintains the state in which the lift amount of the second intake valve reaches the peak for a certain period of time, and includes the timing when the lift amount of the first intake valve reaches the peak within the fixed period. In the period of, the lift amount of the first intake valve is larger than the lift amount of the second intake valve, and is on the advance side and the retard side of the first period within the fixed period. The valve control device according to claim 1, wherein the lift amount of the second intake valve is controlled to be larger than the lift amount of the first intake valve in the second period.
9. The first intake valve and the second intake valve are set to operate the on-off valve multiple times in one cycle.
   In the control device, the plurality of peak values of the lift amount of the first intake valve are larger than the lift amount of the second intake valve at the peak timing, and the lift amount of the second intake valve is large. The valve control device according to claim 1, wherein a plurality of peak values are controlled to be larger than the lift amount of the first intake valve at the peak timing.
10. The control device matches the timing when the lift amount of the first intake valve reaches the peak and the timing when the lift amount of the second intake valve reaches the peak, and the peak of the lift amount of the first intake valve. The value and the peak value of the lift amount of the second intake valve are made different, and further, at least one of the valve opening start timing and the valve opening end timing between the first intake valve and the second intake valve. The valve control device according to claim 1, which controls the opening / closing drive of the first intake valve and the second intake valve so as to shift the valve.
11. It is a valve control method of a control device for controlling the opening / closing drive of the first intake valve and the second intake valve provided in the intake port communicating with the inside of the cylinder of the internal combustion engine.
    The first intake is such that the control device reverses the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve at least once during one cycle of the internal combustion engine. A valve control method for controlling the lift amount of the valve and the lift amount of the second intake valve.

Images