JP7412595B2 - Valve control device and valve control method - Google Patents

Description

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

In recent years, various efforts have been made to meet the demands for improving engine performance in automobiles, such as improving fuel efficiency and reducing exhaust emissions. (abbreviated as “flow”)). In particular, in a method called DI (Direct Injection) in which fuel is injected directly into the cylinder, it is necessary to mix the injected fuel with the intake air in an extremely short period of time, so the strength of the in-cylinder flow increases the It has a large influence on the formation and subsequent combustion performance.

Methods to strengthen the flow in the cylinder include improving the shape of the intake port and piston crown, or dividing the inside of the intake port into upper and lower parts and using a tumble control valve to restrict the flow to one side. There is a method to strengthen the tumble, which is a vertical vortex, in the cylinder by raising the cylinder. There is also a method of generating a horizontal swirl (swirling flow) within the cylinder by blocking the flow to one of the left and right intake ports with a swirl control valve.

In addition, the in-cylinder flow is also changed by controlling the valve timing of the intake valve and exhaust valve as other means. In connection with this, Patent Document 1 discloses a method of generating swirl in a cylinder by using a difference in valve profile between two intake valves.

Japanese Patent Application Publication No. 11-229913

The technology described in Patent Document 1 differs the valve lift curves of two intake valves and generates 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 necessarily sufficient. was not something that could be obtained.

Under the above circumstances, there has been a demand for a method that can further strengthen the in-cylinder flow when generating swirl in the cylinder due to the difference in opening between the two intake valves.

In order to solve the above problems, a valve control device according to one aspect of the present invention controls the opening/closing drive of a first intake valve and a second intake valve provided in an intake port communicating with the inside of a cylinder of an internal combustion engine. The first intake valve is controlled 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. and a control device for controlling the lift amount of the second intake valve and the lift amount of the second intake valve.

According to at least one aspect of the present invention, it is possible to generate a swirl in the cylinder due to the difference in opening between two intake valves, and to reverse the rotational direction of the swirl midway. This makes it possible to further strengthen the in-cylinder flow.
Problems, configurations, and effects other than those described above will be made clear by the following description of the embodiments.

1 is a schematic configuration diagram of an engine to which the present invention is applied. FIG. 2 is a schematic diagram showing an intake valve and an exhaust valve. FIG. 2 is a block diagram showing an example of a hardware configuration of an ECU. FIG. 3 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of two intake valves according to the first embodiment of the present invention. FIG. 5 is a schematic diagram showing changes in the direction of swirl within the combustion chamber when two intake valves are operated according to the valve lift curve of FIG. 4. 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 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 the 1st Embodiment of this invention. 3 is a simulation result of analyzing the sensitivity of the swirl ratio to the phase difference in valve timing at which the valve lift amount is maximum in the first embodiment of the present invention. 3 is a simulation result of analyzing the sensitivity of the tumble ratio to the phase difference in valve timing at which the valve lift amount is maximum in the first embodiment of the present invention. 3 is a simulation result of analyzing the sensitivity of turbulent flow kinetic energy to a phase difference in valve timing at which the valve lift amount is maximum in the first embodiment of the present invention. 3 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 amount is maximum in the first embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of two intake valves according to the second embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the third embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the fourth embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the fifth embodiment of the present invention. FIG. 18 is a schematic diagram showing changes in the direction of swirl within the combustion chamber when two intake valves are operated according to the valve lift curve of FIG. 17; FIG. 7 is another operating characteristic curve diagram (valve lift curve) of the intake valve in the fifth embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the sixth embodiment of the present invention. FIG. 12 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the seventh embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the first example of the ninth embodiment of the present invention. FIG. 7 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of an intake valve according to a second example of the ninth embodiment of the present invention.

Hereinafter, examples of modes 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 this specification and the accompanying drawings, components having substantially the same functions or configurations are given the same reference numerals and redundant explanations are omitted.
1. First embodiment (example where there is a phase difference between the peak timings of two intake valves)
2. Second embodiment (example where the valve lift curve has a flat portion on the valve opening side or valve closing side)
3. Third embodiment (example where two intake valves have different peak timings and peak values)
4. Fourth embodiment (example where the peak timings of two intake valves are both advanced)
5. Fifth embodiment (example where one of the two intake valves has one peak and the other has two peaks)
6. Sixth embodiment (example where one valve lift curve of two intake valves has a flat part)
7. Seventh embodiment (example where the valve lift curves of two intake valves have multiple peaks)
8. Eighth embodiment (example where two intake valves have the same peak timing but different peak values and different valve closing timings)
9. Ninth embodiment (example where two intake valves have the same peak timing but different peak values and different opening/closing valve timings)

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 diagram showing an intake valve and an exhaust valve.

In FIG. 1, an engine 100 has an intake port 4 and an exhaust port 5 connected to a combustion chamber 12 made up of a cylinder 1, a cylinder head 2, and a piston 3. A connecting 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. The combustion chamber 12 and the intake port 4 are partitioned off by a pair of intake valves 6a and 6b. Further, the combustion chamber 12 and the exhaust port 5 are partitioned off by a pair of exhaust valves 7a and 7b.

The engine 100 generates mixture 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 has a mechanism for letting energy in and out. That is, in normal operating conditions, the intake valves 6a and 6b are closed during the exhaust stroke, and as the piston 3 rises, the exhaust valves 7a and 7b open, allowing the air to flow from the combustion chamber 12 to the exhaust port 5. Exhaust is performed. In the following intake stroke, the exhaust valves 7a and 7b are closed, and as the piston 3 descends, the intake valves 6a and 6b open, so that air is taken into the combustion chamber 12 from the intake port 4.

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

Furthermore, a fuel injection valve 10 that injects fuel and a spark plug 11 that ignites 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 for converting reciprocating motion by the piston 3 into rotational motion, and sends an output signal to the engine control unit (ECU). 20.

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

That is, the ECU 20 controls the valve timing, valve lift curve, etc. related to the opening/closing of the intake valves 6a and 6b via the intake valve drive devices 8a and 8b. Further, the ECU 20 controls valve timing, valve lift curves, etc. related to the opening/closing 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, injection pulse width, etc. in the fuel injection valve 10, and controls the ignition timing, etc. in the ignition plug 11.

[ECU hardware configuration]
FIG. 3 is a block diagram showing an example of the hardware configuration of the ECU 20. As shown in FIG.
The ECU 20 includes an input circuit 191, an A/D conversion section 192, a CPU (Central Processing Unit) 193 that 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 develops a program stored in the ROM 194 (an example of a storage unit) into the RAM 195 and executes it, thereby realizing a plurality of functions described later in this embodiment. CPU 193 is an example of a control device. For example, the CPU 193 generates a control signal that controls opening and closing of the intake valves 6a and 6b, and performs control to output the control signal to the intake valve drive devices 8a and 8b and the exhaust valve drive devices 9a and 9b.

The input circuit 191 takes in signals output from the sensors 200 as input signals 190. The sensors 200 include, 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 noise components from the input signal 190, and converts the noise-removed signal into an A/D converter. 192.

The A/D converter 192 converts the 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 variety of calculations, diagnosis, control, etc. by executing control logic (program) stored in a storage medium such as the ROM 194. . Note that the calculation results of the CPU 193 and the conversion results of the A/D converter 192 are temporarily stored in the RAM 195. Further, in this embodiment, as the ROM 194, a nonvolatile 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 implementing the valve control method of the present invention is written is stored in the 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 to control a controlled object 210 such as an actuator for driving the engine 100. The objects to be controlled are, for example, 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.

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

The communication circuit 199 is a communication interface that is connected to a communication device (not shown) and other ECUs so as to be able to transmit and receive data.

<1. First embodiment>
Next, a 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 explained with reference to FIG. 4.

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

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

In this embodiment, the intake valve drive device 8a synchronizes the 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 lifts the valve of the intake valve 6a. The valve timing (crank angle Pa) at which the amount is maximum is advanced more than usual to obtain a left-right asymmetric valve lift curve C6a. Similarly, the intake valve driving device 8b synchronizes the opening start timing and closing end timing of the intake valve 6b with the opening start timing and closing end timing of the intake valve 6a, and adjusts the valve lift amount of the intake valve 6b. The maximum valve timing (crank angle Pb) is retarded than usual to create a left-right asymmetric valve lift curve C6b. That is, the phase difference Dp is adjusted to the valve timing (crank angles Pa, Pb) at which the valve lift amount of the intake valves 6a and 6b is maximum without changing the opening start timing and the 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, the rate of change in the valve lift amount for the intake valve 6a until the valve lift amount reaches the maximum is large, and after the peak until the valve closes, the rate of change in the valve lift amount is large. The rate of change in valve lift 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 reaches the maximum is smaller than that of the intake valve 6b, and after the peak until the valve closes, The rate of change in valve lift is large.

As described above, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU 193) 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 in the lift amount of the second intake valve (crank angle Pb) until the lift amount reaches its peak.

According to the valve control device according to the present embodiment configured in this way, 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 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 its peak is different from the timing at which the lift amount of the second intake valve reaches its peak (the phase difference Dp is ) can be provided. Since the lift amounts of the two intake valves reach their peaks at different times during one cycle (intake period), the magnitude relationship between the lift amounts of the two intake valves is reversed at least once (once in Figure 4). , it becomes possible to reverse the rotational direction of the swirl within the combustion chamber 12.

[Change in direction of swirl]
FIG. 5 is a schematic diagram showing changes in the direction of swirl within the combustion chamber 12 when the intake valves 6a and 6b are operated according to the valve lift curve of FIG. A swirl is a vortex (transverse vortex) of air flow that is 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, the intake valve 6a is initially opened wider than the intake valve 6b, as shown in the upper part of FIG. Flow rate increases. Therefore, a clockwise swirl SWa is formed in the combustion chamber 12 due to the flow rate difference.

Thereafter, as shown in the lower part of FIG. 5, on the contrary, the intake valve 6b becomes more open than the intake valve 6a, and the flow rate of air flowing from the intake valve 6b side increases this time. Therefore, a counterclockwise swirl SWb is formed in the combustion chamber 12 due to the flow rate difference. That is, the rotational direction of the swirl generated within the combustion chamber 12 is reversed during the intake stroke.

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

(Change in swirl ratio)
FIG. 6 shows simulation results showing changes in swirl ratio in the first embodiment. The horizontal axis in 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 rotational speed of the swirl to the rotational speed of the engine.

If there is no phase difference between the valve timings at which the valve lift amount of the intake valves 6a and 6b is maximum, the air flows into the cylinder from the left and right intake valves 6a and 6b in the same way, and there is no bias, which is indicated by the broken line. As such, no swirl occurs. On the other hand, if there is a phase difference in the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximum, as shown by the solid line, the swirl ratio initially becomes negative (in the clockwise direction shown in FIG. 5). It has become. Thereafter, the swirl ratio changes to positive (counterclockwise direction shown in FIG. 5), indicating that the direction of rotation of the swirl is reversed midway.

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

It is shown that when there is a phase difference between the valve timings at which the valve lift amount of the intake valves 6a and 6b is maximum, the tumble is also stronger than when there is no phase difference. From the start of valve opening until around the valve timing (crank angle Pr) when the valve lift amounts of the intake valves 6a and 6b are reversed, there is no phase difference due to the collision of the intake air taken in from the intake valves 6a and 6b. The tumble (dashed line) is stronger than the tumble (solid line) when there is a phase difference. Thereafter, when the valve lift amounts of the intake valves 6a and 6b are reversed, the direction of rotation of the swirl is reversed and the flow is disturbed. That is, when the valve lift amount is reversed, part of the flow in the horizontal direction shifts to the diagonal direction or the vertical direction. Therefore, as the piston 3 approaches top dead center from around the time when the valve lift amount is reversed, the strength of the tumble in the absence of a phase difference decreases, but the strength of the tumble in the case of a phase difference maintains a higher strength. .

(Change in kinetic energy of turbulent flow)
FIG. 8 is a simulation result showing changes in the kinetic energy of turbulent flow in the cylinder in the first embodiment. The horizontal axis in FIG. 8 represents the crank angle [°bTDC], and the vertical axis represents the turbulent kinetic energy [mJ].
If there is a phase difference between the valve timings at which the valve lift amount of the intake valves 6a and 6b is maximum, the flow will be disturbed when the rotating direction of the swirl shown in FIG. 6 is reversed, compared to the case where there is no phase difference. It has been shown that this occurs, and the subsequent turbulent kinetic energy increases.

(Change in kinetic energy of average flow)
FIG. 9 shows simulation results showing changes in the kinetic energy of the average flow in the first embodiment. The horizontal axis in 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 maximum, the difference shown in FIG. 6 is greater than when there is no phase difference. It is shown that the kinetic energy of the average flow increases after the direction of rotation of the swirl is reversed.

As shown from the above simulation results, without changing the valve opening start timing and valve closing end timing of the two intake valves 6a and 6b, one intake valve advances the valve timing at which the valve lift amount is maximum. 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 in the timing at which the valve lift amount of the two intake valves 6a and 6b is maximum, a difference occurs in the flow rate of air from the two intake valves 6a and 6b, and a swirl occurs, and the rotation thereof The direction is reversed midway, 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 can be improved, and the combustion performance of the engine 100 can be improved.

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

(Swirl ratio sensitivity analysis results)
FIG. 10 is a simulation result of analyzing the sensitivity of the swirl ratio to the phase difference in valve timing at which the valve lift amount of the two intake valves 6a and 6b is maximum in the first embodiment. In FIG. 10, the horizontal axis represents the crank angle [°bTDC], and the vertical axis represents the swirl ratio. Here, we compare the changes in the swirl ratio in cylinder 1 when the phase difference in valve timing at which the valve lift amount is maximum is set to 40 degrees, 60 degrees, 80 degrees, 100 degrees, and 120 degrees in terms of crank angle. are doing.

In Figure 10, no matter what the crank angle is, the value of the swirl ratio turns from negative to positive from the time the two intake valves start opening to the time they end closing. It is shown that the direction reverses halfway. The magnitude of the swirl ratio after the value of the swirl ratio changes from negative to positive increases in accordance with the phase difference in valve timing at which the valve lift amount is maximum.

However, regarding the magnitude of the absolute value of the swirl ratio in the negative direction that initially occurs immediately after the valve starts opening, there are two cases: when the phase difference is from 40 degrees to 100 degrees and when the phase difference is from 100 degrees to 120 degrees. The increase width of the absolute value of the swirl ratio is different. In other words, when the phase difference is 100 degrees or more, the sensitivity of the swirl ratio immediately after the valve starts increases, and there is a large difference in the level of the swirl ratio when the phase difference is 80 degrees or less and when it 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 at the beginning, as seen at 40 degrees, 60 degrees, and 80 degrees, but when the phase difference is 120 degrees, It was only slightly larger. Therefore, it can be said that it is desirable that the difference in valve timing (phase difference) at which the valve lift amount of the two intake valves 6a and 6b is maximum is 100 degrees or more.

In this way, by setting the phase difference in the valve timing to 100 degrees or more, it is possible to make the difference in the strength of the reversed swirl larger than when the phase difference in the valve timing is less than 100 degrees, and to improve the in-cylinder flow. can be further strengthened.

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

In FIG. 11, it is shown that the larger the phase difference between the valve timings at which the valve lift amount of the two intake valves 6a and 6b is maximum, the stronger the tumble becomes as a whole. Although not shown, the same tendency was observed even when the phase difference in valve timing was 40 degrees, 60 degrees, and 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 turbulent flow in the cylinder 1 to the phase difference in valve timing that maximizes the valve lift amount of the two intake valves 6a and 6b in the first embodiment. . The horizontal axis in 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 rotating direction of the swirl shown in FIG. 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 phase difference in valve timing was 40 degrees, 60 degrees, and 140 degrees.

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

In FIG. 13, as in the case of turbulent kinetic energy, a difference occurs in the kinetic energy of the average flow from the timing after the swirl rotation method shown in FIG. 10 is reversed. That is, FIG. 13 shows a tendency that the larger the phase difference between the valve timings at which the valve lift amount of the two intake valves 6a and 6b becomes maximum, the larger the kinetic energy of the average flow becomes. Although not shown, the same tendency was observed even when the phase difference in valve timing was 40 degrees, 60 degrees, and 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 A valve control device that controls the opening/closing drive of a second intake valve (intake valve 6b), the valve control device controlling the lift amount of the first intake valve and the lift amount of the second intake valve during one cycle of the internal combustion engine. A control device (CPU 193) is provided that controls the lift amount of the first intake valve and the lift amount of the second intake valve so that the relationship is reversed at least once.

According to the valve control device according to the first embodiment configured as described above, by reversing the magnitude relationship between the lift amount of the first intake valve and the lift amount of the second intake valve at least once, The rotational direction of the swirl generated in the cylinder can be reversed during the intake operation due to the difference in the opening degrees of the two intake valves. This makes it possible to further strengthen the in-cylinder flow.

Furthermore, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU 193) determines the timing (crank angle Pa) when the lift amount of the first intake valve (intake valve 6a) reaches its peak, and the timing when the lift amount of the first intake valve (intake valve 6a) reaches its peak. 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 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 at least once.

Furthermore, in the valve control device (ECU 20) according to the present embodiment, the control device (CPU 193) determines the timing (crank angle Pa) when the lift amount of the first intake valve (intake valve 6a) reaches its peak, and the timing when the lift amount of the first intake valve (intake valve 6a) reaches its peak. Control is performed so that the difference from the timing (crank angle Pb) at which the lift amount of the intake valve (intake valve 6a) reaches its peak is 100 degrees or more in terms of crank angle.

According to the valve control device according to the present embodiment configured in this way, by setting the phase difference between the timings at which the lift amounts of the two intake valves reach their peaks to be 100 degrees or more, a swirl is created before and after the rotation direction is reversed. The difference in strength can be made larger. By increasing the difference in strength of the reversed swirl, 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 (CPU 193) starts opening the valve 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 as described above, by controlling the opening/closing drive of the two intake valves by matching the valve opening start timing and the valve opening end timing between the two intake valves, It is possible to further increase the in-cylinder flow rate while performing intake at an optimal period designed in advance.

<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. 14. This embodiment also targets the engine 100 shown in FIG.

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

In FIG. 4 described above, after the valve lift amount of the intake valve 6a reaches the maximum, the valve lift amount gradually decreases, but as shown in FIG. You may also give it a period of time in which it becomes constant. Similarly, in FIG. 4, the valve lift amount of the intake valve 6b gradually increases until it reaches the maximum value, but as shown in FIG. A period during which the lift amount is approximately constant may be provided.

In this way, by providing a period in which the valve lift amount is maintained constant during the valve lift, it is possible to form an asymmetrical valve lift curve centered around the center of the valve opening start time and valve opening end time. can. Therefore, it is possible to provide a phase difference to the valve timing at which the valve lift amount of the two intake valves 6a and 6b becomes maximum. Thereby, a swirl is generated in the combustion chamber 12 due to the difference in opening between the intake valves 6a and 6b, and the direction of rotation thereof is reversed midway, thereby further strengthening the in-cylinder flow.

<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. 15. This embodiment also targets the engine 100 shown in FIG.

FIG. 15 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the two intake valves 6a and 6b according to the third embodiment. In FIG. 15, the horizontal axis 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 valve lift amounts of the intake valves 6a and 6b are the same, but as shown in FIG. It is also possible to change the maximum value of the valve lift amount. That is, in the valve control device (ECU 20) according to the third embodiment, the control device (CPU 193) determines the peak value of the lift amount of the first intake valve (crank angle Pa) and the peak value of the lift amount of the first intake valve (crank angle Pa). 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 phase difference Dp between the valve timings at which the valve lift amount of the intake valves 6a and 6b reaches its peak is the same as the phase difference Dp in FIG. 4.

As explained in the first and second embodiments, the difference in opening between the intake valves 6a and 6b at the valve timing when the valve lift amount is maximum affects the strength of the swirl (in-cylinder flow). Furthermore, 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 the opening degree of the intake valves 6a and 6b changes, and the intensity of the generated swirl can be controlled. becomes possible.

For example, in the example shown in FIG. 15, after the valve timing (crank angle Pr) at 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 increases, and the intensity of the swirl increases. Furthermore, 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 (same as the valve timing at which the valve lift curve Cn reaches its peak). Then, the angle changes to the advanced angle side. In this way, by advancing the valve timing in which the valve lift amounts of the two intake valves are reversed, the strength of the swirl at the ignition and combustion timing increases compared to when the valve timing is not advanced, and the in-cylinder flow increases. will be further strengthened.

In addition, in FIG. 15, the valve timing (crank angle Pr) at which the valve lift amounts of the intake valves 6a and 6b are reversed changes to the advanced side from the valve timing at which the valve lift curve Cn reaches its peak. It is not excluded that the valve timing changes to the retarded 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. 16. This embodiment also targets the engine 100 shown in FIG.

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

FIG. 16 shows that the maximum values of the valve lift amounts of the intake valves 6a and 6b are the same, but the valve timing at which the valve lift amount of the intake valves 6a and 6b is the maximum is different from that of the valves of the first and second embodiments. This is on the advanced side compared to the timing (valve timing at which the valve lift curve Cn reaches its peak). That is, in FIG. 16, the valve timing (crank angle Pr) at which the valve lift amounts of the two intake valves 6a and 6b are reversed is changed to the more advanced side than the valve timing of the first and second embodiments. .

The fourth embodiment configured as described above advances the valve timing at which the valve lift amounts of the two intake valves are reversed, but does not advance the valve timing as in the third embodiment. The intensity of the swirl at the ignition/combustion timing can be increased compared to the case where the This further strengthens the in-cylinder flow.

Note that in FIG. 16, the valve timing at which the valve lift amount of the intake valves 6a and 6b is maximum is advanced from the valve timing at which the valve lift curve Cn reaches its peak, but this is not limited to this example. In other words, control may be performed so that the difference in valve timing at which the valve lift curve C6a and the valve lift curve Cn reach a peak becomes larger than the difference in valve timing at which the valve lift curve C6b and the valve lift curve Cn reach a peak.

In addition, in FIG. 16, the valve timings (crank angles Pr, Pb) at which the valve lift amounts of the intake valves 6a and 6b peak are changed to the advanced side compared to the valve timing at the peak of the valve lift curve Cn. , it is not excluded that the valve timing changes to the retarded 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. This embodiment also targets the engine 100 shown in FIG.

[Valve lift curve]
FIG. 17 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the two intake valves 6a and 6b according to the fifth embodiment. The horizontal axis in 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 once during one cycle, and the intake valve 6b opens and closes twice during one cycle. The CPU 193 of the ECU 20 synchronizes the first opening start timing of the intake valve 6a and the first opening start timing of the intake valve 6b, and also adjusts the closing end timing of the intake valve 6a and the second closing start timing of the intake valve 6b. Match 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 timings at which these peak values occur.

Note that 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 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. In addition, the intake valve 6b is completely closed in the first opening/closing operation (valve lift amount becomes 0), and then the second opening/closing operation is performed, but before it is completely closed, The opening/closing valve operation may be performed for the second time.

[Change in direction of swirl]
FIG. 18 is a schematic diagram showing changes in the direction of swirl within the combustion chamber 12 when the intake valves 6a and 6b are operated according to the valve lift curve of FIG. 17.
As shown in FIG. 18, when looking over time, first the valve lift amount of the intake valve 6b is larger than the valve lift amount of the intake valve 6a, so the flow rate of air entering from the intake valve 6b is large, and the amount of air entering the combustion chamber 12 is large. A counterclockwise swirl SWb is formed (upper row of FIG. 18). Next, the valve lift amount of the intake valve 6a increases, the valve lift amount of the intake valve 6b decreases, and the flow rate of air from the intake valve 6a increases, creating a clockwise swirl SWa ( Figure 18 middle row). Furthermore, as 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 forming the counterclockwise swirl SWb increases again. (lower row of Figure 18).

In other words, by varying the number of times the two intake valves 6a and 6b are opened, the difference in opening between the two intake valves 6a and 6b can be changed over time. By changing the direction of the generated swirl, it becomes possible to increase the turbulence of the air within 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) is opened and closed once during one cycle, and the second intake valve (intake valve 6b) is opened and closed once during one cycle. is set to open and close the valve twice in one cycle. Then, the control device (CPU 193) determines that 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 that the peak value of the lift amount of the second intake valve is 1 The second and second peak values are controlled to be larger than the lift amount of the first intake valve at the peak timing.

In the fifth 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 twice. As a result, the rotational direction of the swirl generated in the cylinder due to the difference in the opening degree of the two intake valves is reversed twice during the intake operation, causing a more complicated air flow than when reversing once. It becomes possible to strengthen the flow.

<Modification of fifth embodiment>
In the fifth embodiment described above, when the intake valve 6b opens and closes twice in one cycle, the valve opens and closes 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). In FIG. 19, the horizontal axis represents the crank angle, and the vertical axis represents the valve lift amount.
As shown in FIG. 19, a pause period Ti is provided between the first closing end timing and the second opening start timing of the intake valve 6b. It is configured to widen the interval between opening and closing valve operations. Even with this 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 the in-cylinder flow is further improved than when reversed once. It becomes possible to strengthen the

<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. 20. This embodiment also targets the engine 100 shown in FIG.

FIG. 20 is an operating characteristic curve diagram (valve lift curve) showing the relationship between the valve lift amount and crank angle of the intake valve according to the sixth embodiment. In FIG. 20, the horizontal axis 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 generally triangular shape, with the valve lift amount reaching a maximum (peak) at the center (crank angle Pa) of the valve lift curve C6a. On the other hand, the valve lift curve C6b of the intake valve 6b has a larger rate of change in rise and fall than the valve lift curve C6a of the intake valve 6a, and has a period (flat portion) during which the maximum value is maintained. It is shaped like a shape. In this example, the valve timing in the middle of the period during 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, both sides (advanced side In 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 opening start timing and the closing end timing of the intake valve 6a and the intake valve 6b are the same.

Therefore, initially the opening amount of the intake valve 6b is greater than the opening amount of the intake valve 6a, and then, around the area where the valve lift amount of the intake valve 6a is maximum, the opening amount of the intake valve 6a is larger than the opening amount of the intake valve 6a. This is larger than the opening amount of the intake valve 6b. Thereafter, the opening amount of the intake valve 6b becomes larger than the opening amount of the intake valve 6a again.

Therefore, in this embodiment as well, as shown in FIG. 18, since the flow rate of air from the intake valve 6b is large at first after the valve opening starts, a counterclockwise swirl SWb is formed in the combustion chamber 12, and then, An increase in the flow rate of air from the intake valve 6a induces a clockwise swirl SWa, and then an increase in the flow rate of air from the intake valve 6b causes a counterclockwise swirl SWb to be formed again. become. Even if symmetrical valve lift curves C6a and C6b are used for the two intake valves 6a and 6b, the difference in valve lift amount will cause a difference in flow rate, and the direction of the swirl formed in the combustion chamber 12 will change. 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) are opened and closed once during one cycle. is set to do so. Then, the control device (CPU 193) maintains the state in which the lift amount of the second intake valve reaches its peak for a certain period of time, and controls the timing (crank angle 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 lift amount is more advanced than the first period within a certain period. In the second period (period T2) on the side and 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 set to 2 while the second intake valve is maintained in the open state. It can be reversed several times. As a result, the rotational direction of the swirl generated in the cylinder due to the difference in the opening degree of the two intake valves is reversed twice during the intake operation, causing a more complicated air flow than when reversing once. 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. 21. This embodiment also targets the engine 100 shown in FIG.

In this embodiment, the opening start and closing timings of the intake valves 6a and 6b are aligned, and the valve lift curves of the intake valves 6a and 6b each have a plurality of peaks, and the phase at which the peak occurs Assume that they are shifted from each other. That is, near multiple 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 other hand, near multiple 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 and crank angle of the intake valve according to the seventh embodiment. In FIG. 21, the horizontal axis 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 relationship of the valve lift amounts of the intake valves 6a and 6b is different occurs a total of four times. The larger the lift amount of the intake valve, the greater the flow rate of air flowing into the combustion chamber 12, causing a swirl within the combustion chamber 12. Therefore, each time the valve lift changes in magnitude, a flow occurs in the opposite direction. Therefore, according to the valve lift curves C6a and C6b, the effect of reversing the rotating direction of the swirl three times is activated, and a more complicated flow is generated, thereby strengthening the in-cylinder flow.

Although a case has been described in which the valve lift curves C6a and C6b of the intake valves 6a and 6b each have two peaks, the number of peaks in the valve lift curves of the intake valves 6a and 6b may be three or more. In addition, the intake valves 6a and 6b perform a second opening/closing operation before they are completely closed in the first opening/closing operation (the valve lift amount becomes 0), but they are completely closed once. After that, the second opening/closing valve operation may be performed.

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) are opened and closed multiple times during one cycle. is set to do so. Then, the control device (CPU 193) determines that 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 The plurality of peak values of are controlled to be larger than the lift amount of the first intake valve at the peak timing.

In the seventh embodiment configured as described above, while the second intake valve is kept open, a plurality of magnitude relationships between the lift amount of the first intake valve and the lift amount of the second intake valve are set. It can be reversed several times. This number of reverse rotations is the sum of the number of peaks of valve lift amounts of the two intake valves. As a result, the rotational 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 during the intake operation, causing a more complicated air flow than when the swirl is reversed once or twice. Furthermore, it becomes possible to strengthen the in-cylinder flow.

<8. Eighth embodiment>
In the first to seventh embodiments described above, by aligning the opening and closing timings of the intake valves 6a and 6b, it is possible to avoid changing from the pre-designed optimal timing for intake and exhaust. desirable. However, it is also possible to make the opening and closing timings of the intake valves 6a and 6b different from each other. In this case as well, by giving a phase difference to the valve timing at which the valve lift amount of the intake valves 6a and 6b reaches its maximum value (peak), a difference in opening degree occurs between the intake valves 6a and 6b, and a swirl occurs. , and the opening degrees of the intake valves 6a and 6b are switched. Then, the direction of the swirl generated within 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 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. In FIG. 22, the horizontal axis 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 reaches a peak at the crank angle Pa. Further, the valve lift curve C6b of the intake valve 6b reaches a peak at the crank angle Pb, which is the same 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 maximum. 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, although the valve lift curve C6a is approximately symmetrical around the valve timing (crank angle Pa) that reaches its peak, the valve lift curve C6b shows that the rate of change in valve lift amount after the peak is higher than the rate of change in the valve lift amount until the peak. The rate of change in valve lift until valve opening is small. From another perspective, the opening timing of the intake valve 6a is the same as the opening timing of the intake valve 6b, but the closing timing of the intake valve 6a is earlier than the closing 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 and crank angle of the intake valve according to the second example of the ninth embodiment. In FIG. 23, the horizontal axis 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 reaches a peak at the crank angle Pa. Further, the valve lift curve C6b of the intake valve 6b reaches a peak at the crank angle Pb, which is the same as the crank angle Pa. That is, the intake valves 6a and 6b have the same valve timing at which the valve lift amount reaches its 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 about the valve timings (crank angles Pa and Pb) that are approximately at their peaks. However, the rate of change in the amount of valve lift until the valve lift curve C6a reaches its peak and the rate of change in the amount of valve lift from the peak until the valve closes are respectively the amount of valve lift until the valve lift curve C6b reaches its peak. is larger than the rate of change in the valve lift amount from the peak until the valve closes. From another perspective, the opening timing of the intake valve 6a is later than the opening timing of the intake valve 6b, and the closing timing of the intake valve 6a is earlier than the closing timing of the intake valve 6b.

As described above, in the valve control device (ECU 20) according to the ninth embodiment, the control device (CPU 193) controls the timing at which the lift amount of the first intake valve (intake valve 6a) reaches its peak and the timing at which the lift amount of the first intake valve (intake valve 6a) reaches its peak. In addition to matching the timing (crank angles Pa, Pb) at which the lift amount of the valve (intake valve 6b) reaches its peak, 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 The first intake valve and the second intake valve are different from each other, and further, 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 opening/closing drive.

In this embodiment configured in this way, even when the valve timings at which the lift amounts of the first intake valve and the second intake valve reach their peaks are matched, a difference in opening degree occurs between the two intake valves. can generate swirl inside the cylinder. Furthermore, in this embodiment, since the opening degrees of the two intake valves can be switched, the direction of the swirl is reversed and the in-cylinder flow is further strengthened.

Furthermore, the present invention is not limited to the embodiments described above, and it goes without saying that various other applications and modifications may be made without departing from the gist of the present invention as set forth in the claims.
For example, each of the embodiments described above describes valve control of an engine control unit (valve control device) in detail and specifically in order to explain the present invention in an easy-to-understand manner, and does not necessarily include all of the described components. but not limited to. Moreover, it is possible to replace a part of the configuration of one embodiment with the component of another embodiment. It is also possible to add components of other embodiments to the configuration of one embodiment. Further, it is also possible to add, replace, or delete other components to a part of the configuration of each embodiment.

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

DESCRIPTION OF SYMBOLS 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...Spark 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...Crank angle at which the valve lift amount peaks

Claims (6)

A valve control device that controls opening/closing driving of a first intake valve and a second intake valve provided in an intake port communicating with the inside of a cylinder of an internal combustion engine,
The lift amount of the first intake valve and the lift amount of the second intake valve are reversed twice during one cycle of the internal combustion engine. comprising a control device for controlling the lift amount of the second intake valve ;
The first intake valve is set to perform an on-off valve operation once during one cycle, and the second intake valve is set to perform an on-off valve operation twice during one cycle,
The control device is configured such that 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 first lift amount of the second intake valve is larger than the lift amount of the second intake valve at the peak timing. and controlling the second peak value to be larger than the lift amount of the first intake valve at the peak timing.
Valve control device. The control device is configured to match the opening start timing of the first intake valve and the first opening start timing of the second intake valve, and to match the closing end timing of the first intake valve and the first opening start timing of the second intake valve. Align with the second closing end timing of intake valve 2.
The valve control device according to claim 1. A valve control device that controls opening/closing driving of a first intake valve and a second intake valve provided in an intake port communicating with the inside of a cylinder of an internal combustion engine,
The lift amount of the first intake valve and the lift amount of the second intake valve are reversed at least three times during one cycle of the internal combustion engine. comprising a control device that controls a lift amount of the second intake valve ,
The first intake valve and the second intake valve are set to perform open/close valve operations multiple times during one cycle,
The control device is configured such that 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 larger than the lift amount of the second intake valve at the peak timing. Control is performed such that the plurality of peak values are larger than the lift amount of the first intake valve at the peak timing.
Valve control device. The control device synchronizes the first valve opening start timing and the final valve opening end timing between the first intake valve and the second intake valve, and controls the first intake valve and the second intake valve. The valve control device according to claim 3 , wherein the valve control device controls opening and closing drive of an intake valve. A valve control method for a control device that controls opening/closing driving of a first intake valve and a second intake valve provided in an intake port communicating with the inside of a cylinder of an internal combustion engine, the method comprising:
The control device controls the first intake valve 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 twice during one cycle of the internal combustion engine. and the lift amount of the second intake valve ,
The first intake valve is set to perform an on-off valve operation once during one cycle, and the second intake valve is set to perform an on-off valve operation twice during one cycle,
The control device is configured such that 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 first lift amount of the second intake valve is larger than the lift amount of the second intake valve at the peak timing. and controlling the second peak value to be larger than the lift amount of the first intake valve at the peak timing.
Valve control method. A valve control method for a control device that controls opening/closing driving of a first intake valve and a second intake valve provided in an intake port communicating with the inside of a cylinder of an internal combustion engine, the method comprising:
The control device controls the first intake valve 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 three times during one cycle of the internal combustion engine. controlling the lift amount of the valve and the lift amount of the second intake valve ;
The first intake valve and the second intake valve are set to perform open/close valve operations multiple times during one cycle,
The control device is configured such that 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 larger than the lift amount of the second intake valve at the peak timing. Control is performed such that the plurality of peak values are larger than the lift amount of the first intake valve at the peak timing.
Valve control method.

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