JP4602383B2 - Control device for variable valve internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve operating internal combustion engine and a control method used in a vehicle such as an automobile, and more particularly to a variable valve that performs intake air amount control by continuously controlling a lift amount and a valve opening period of an intake valve. The present invention relates to a valve-type internal combustion engine and a control method.

  In recent years, for the purpose of reducing the fuel consumption of an internal combustion engine for automobiles, a variable valve-operated internal combustion engine that controls intake air amount by an intake valve that can variably set a lift amount and a valve opening period is becoming widespread. As a variable valve-operated internal combustion engine, each cylinder has two intake ports and intake valves that individually open and close each intake port. In the low speed region of the internal combustion engine, one of the intake valves is connected to the engine load. Regardless of the height, the valve is closed and fixed, and at least one of the lift amount and the valve opening period of the other intake valve is continuously increased gradually in response to an increase in engine load. There exists what performs swirl control in a combustion chamber (for example, patent documents 1).

JP 7-332045 A

  In a conventional variable valved internal combustion engine such as that disclosed in Patent Document 1, since some intake valves are stopped in the low engine speed operating range, the intake air amount is low in the low engine speed and high load range. It is thought to be insufficient.

  Further, in the conventional variable valve-operated internal combustion engine, no consideration is given to reducing variations in intake air amount due to variations (errors) in the lift amount and valve opening period of the intake valve in the low intake air amount region. Variations in the intake air amount, particularly variations in the intake air amount in the low intake air amount region, greatly reduce the control accuracy of the air-fuel ratio of the air-fuel mixture (fuel-air) and deteriorate engine performance.

  The present invention has been made to solve the above-described problems, and an object thereof is to perform intake air amount control by continuously controlling the lift amount and valve opening period of the intake valve. In an internal combustion engine with a variable valve mechanism that can perform the intake valve, there is no fear that the intake air amount will be insufficient, and highly accurate intake air amount control is performed by reducing variations in the intake air amount due to variations in lift amount and valve opening period. It is an object of the present invention to provide a variable valve operating internal combustion engine and a control method.

  In order to achieve the above-described object, a variable valve-actuated internal combustion engine according to the present invention has a plurality of intake ports for each cylinder and intake valves that individually open and close the intake ports, and lifts the intake valves. In a variable valved internal combustion engine that includes a variable valve mechanism that continuously and variably sets at least one of an amount and a valve opening period, and that controls the amount of intake air using an intake valve, At least one of the lift amount and the valve opening period of the intake valve can be individually variably set for each intake valve, and the plural in one cylinder according to the operating state such as the intake air amount of the internal combustion engine Control means for independently setting and controlling the operation modes of the intake valves.

  According to the variable valve type internal combustion engine of the present invention, the operation mode (lift amount or / and valve opening period) of a plurality of intake valves in one cylinder is independently controlled by the control means according to the operating state of the internal combustion engine. By setting the appropriate operation mode for each intake valve, there is no shortage of intake air amount, and it is possible to reduce variations in intake air amount due to variations in lift amount and valve opening period.

  In the variable valve operating internal combustion engine according to the present invention, the control means pauses at least one intake valve of the plurality of intake valves provided in one cylinder in a low air amount region. In the high air amount region, the intake valve and other intake valves operated in the low air amount region are operated. As a result, there is no shortage of intake air amount, and variations in intake air amount due to variations in lift amount and valve opening period are reduced.

  In the variable valve operating internal combustion engine according to the present invention, the diameters of a plurality of intake ports provided in one cylinder and the corresponding intake valves are different. In this case, the control means stops the intake valve having the larger diameter among the plurality of intake valves provided in one cylinder in the low air amount region, and reduces the intake valve in the middle and high air amount regions. All of the plurality of intake valves provided in one cylinder are operated. As a result, there is no shortage of intake air amount, and variations in intake air amount due to variations in lift amount and valve opening period are reduced.

  Further, the control means operates the intake valve having a larger diameter among the plurality of intake valves provided in one cylinder in the medium air amount region, and pauses the intake valve having the smaller diameter. In the high air volume region, all of the plurality of intake valves provided in one cylinder are operated. As a result, there is no shortage of intake air amount, and variations in intake air amount due to variations in lift amount and valve opening period are reduced.

  In addition, during the transition from the low air amount region to the high air amount region, the control means reduces the intake air amount by the intake valve operated in the low air amount region during the transient change, and in the middle and high air amount regions. The intake air amount by the intake valve to be activated is increased during the transient change, and conversely, during the transition from the high air amount region to the low air amount region, the intake by the intake valve to be operated in the middle and high air amount regions The air amount is decreased during the transient change, and the intake air amount by the intake valve operated in the low air amount region is increased during the transient change. As a result, there is no shortage of intake air amount, and variations in intake air amount due to variations in lift amount and valve opening period are reduced.

  Further, when the control means switches the valve to be operated from the intake valve that is operated in the low air amount region to the intake valve that is operated in the high air amount region, the latter minimum intake air amount is greater than or equal to the former maximum intake air amount. To do.

  Further, the control means is configured to change the low air amount region according to the operation state before the transient change and the operation state after the transient change intended by the driver at the time of the transient change from the low air amount region to the medium to high air amount region. It is also possible to change the amount of decrease in the amount of air passing through the intake valve that is operated in step S1, and to obtain a transient characteristic that is suitable for the operation state before the transient change and the transient operation intended by the driver.

  Further, the variable valve operating internal combustion engine according to the present invention transiently changes the amount of air passing through the intake valve operated in the low load operation region according to the operating state before the transient change and the operating state after the transient change intended by the driver. It is prohibited to increase the amount of air passing through the intake valve operated in the high-load operation region as compared to before the transient change while reducing the amount compared to before the change.

  Further, the variable valve operating internal combustion engine according to the present invention has means for generating a negative pressure upstream of the intake valve in the low air amount region, and the plurality of intake valves provided in one cylinder in the low air amount region. Of these, the intake air amount is controlled by one intake valve. Thereby, the lift amount and valve opening period of the intake valve can be expanded in the low air amount region, and the variation in the intake air amount due to the variation in the lift amount and the valve opening period is further reduced.

  In addition, the variable valve operating internal combustion engine according to the present invention includes a fuel injection valve that individually injects fuel into each of the plurality of intake ports arranged in one cylinder. The respective fuel injection amounts are determined by the respective air amounts that pass through the intake valves provided in one cylinder. Thereby, the generation of the air-fuel mixture in the plurality of intake ports does not become uneven.

  In order to achieve the above object, a control method for a variable valve operating internal combustion engine according to the present invention includes a plurality of intake ports for each cylinder and intake valves that individually open and close each intake port. In the control method of the variable valve operating internal combustion engine, which includes a variable valve mechanism that continuously and variably sets at least one of the lift amount or the valve opening period of the intake valve and controls the intake air amount by the intake valve, At least one of lift amounts or valve opening periods of the plurality of intake valves in one cylinder is individually controlled according to the operating state of the internal combustion engine.

  According to the control method for a variable valve internal combustion engine according to the present invention, the operation mode (lift amount or / and valve opening period) of a plurality of intake valves in one cylinder is determined by the control means in accordance with the operating state of the internal combustion engine. Each is set independently, and the appropriate setting of the operation mode for each intake valve prevents the intake air amount from becoming insufficient, and it is possible to reduce variations in intake air amount due to variations in lift amount and valve opening period. .

  As understood from the above description, according to the variable valve operating internal combustion engine and the control method according to the present invention, the operation modes of a plurality of intake valves provided in one cylinder are individually changed depending on the operation region of the engine. As a result, it is possible to reduce the variation in intake air amount due to variations in the lift amount and valve opening period of the intake valve, eliminate the deterioration in the control accuracy of the air-fuel ratio of the air-fuel mixture caused by the variation in intake air amount, and The performance can be improved.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
(Embodiment 1)
FIG. 1 shows Embodiment 1 of a variable valve operating internal combustion engine according to the present invention. The variable valve internal combustion engine 100 is a gasoline engine for automobiles, and has a piston 4 that can reciprocate in a cylinder wheel 3 formed in the cylinder block 1. The piston 4 is connected to a crank mechanism (not shown) by a connecting rod 2. A cylinder head 5 is attached to the upper part of the cylinder block 1. The cylinder head 5 defines a combustion chamber 6 between the piston 4 and the cylinder head 5. Although only one cylinder (combustion chamber 6) is shown in FIG. 1, a gasoline engine for automobiles is usually a multi-cylinder engine such as a 4-cylinder engine or a 6-cylinder engine.

  An intake port 11 and an exhaust port 21 are formed in the cylinder head 5. A spark plug 9 for spark ignition is attached to the cylinder head 5, and an intake valve 7 for opening and closing the intake port 11 and an exhaust valve 8 for opening and closing the exhaust port 21 are respectively attached. An intake port 11, an exhaust port 21, an intake valve 7 that opens and closes the intake port 11, and an exhaust valve 8 that opens and closes the exhaust port 21 are provided for each cylinder (see FIG. 2).

  The intake valve 7 is provided with a variable valve mechanism 10 that can continuously change the lift amount, the valve opening period, and the phase. A fuel injection valve 12 that injects fuel into the intake port 11 is attached upstream of the intake valve 7.

  The internal combustion engine 100 sucks air from the intake port 11 into the combustion chamber 6 that becomes negative pressure by the reciprocating operation (intake stroke) of the piston 4. The fuel injected from the fuel injection valve 12 into the intake port 11 is sucked into the combustion chamber 6 together with the intake air sucked into the combustion chamber 6.

  The fuel sucked into the combustion chamber 6 is mixed with the air sucked into the combustion chamber 6, ignited by the spark plug 9, and burned. The already burned gas in the combustion chamber 6, that is, the exhaust gas, is discharged out of the combustion chamber 6 from the exhaust port 21 by the reciprocating operation (exhaust stroke) of the piston 4.

  The control unit 13 is of a computer type and includes an engine control unit 16, a variable valve control unit 17, an injector drive circuit 18, a transmission control unit 19, and the like, and operates the internal combustion engine 100 from output signals of various sensors. The state is detected, and the variable valve mechanism 10, the fuel injection valve 12, and the spark plug 9 mounted on the internal combustion engine 100 are controlled according to the detection result.

  Signals input from the various sensors to the control unit 13 are shown below. In the present embodiment, the crank angle, cylinder discrimination signal, throttle opening, accelerator pedal depression amount, brake pedal depression amount, intake air temperature, intake air amount, water temperature, exhaust temperature, and exhaust oxygen concentration are input to the control unit 13. . Only the intake air amount sensor 14 and the throttle opening sensor 15 are shown in the figure.

  The fuel injection and ignition timing for each cylinder is controlled by the control unit 13, and the injection pulse signal and the ignition signal are processed in the control unit 13 to control the injection and ignition timing.

  In the internal combustion engine 100 of the present embodiment, the intake air amount control can be performed by using the intake valve 7 provided with the variable valve mechanism 10 for the purpose of improving fuel efficiency by reducing pump loss. When the intake air amount control is performed using the intake valve 7 provided with the variable valve mechanism 10, the intake air amount is changed by continuously varying the lift amount and the valve opening period of the intake valve 7 in the partial load operation region. Is controlling. Conventionally, the largest pump loss occurs in the idle operation region in which the throttle is fully closed. Therefore, the most effective fuel consumption reduction effect can be obtained by using the variable valve mechanism described in this embodiment. It is an idle operation area.

  However, in order to perform idle operation with the variable valve mechanism, the lift amount and the valve opening period of the intake valve need to be extremely small. Therefore, the intake air amount per cycle due to variations in the lift amount and the valve opening period of the intake valve Variation and intake air amount variation between cylinders occur.

  Therefore, in the present embodiment, the valve seat diameters of the two intake valves provided in one cylinder are configured to be different. FIG. 2 shows the cylinder head 5 viewed from the piston 4 side. In the present embodiment, the intake port 7a has a small valve seat diameter and the intake port 11b has a large valve seat diameter.

  Furthermore, the variable valve mechanism 10 is configured such that the lift amount and the valve opening period of the intake valves 7a and 7b in one cylinder can be individually variably set. The variable valve control unit 17 of the control unit 13 which is a control unit of the variable valve mechanism 10 independently sets and controls the operation modes of the intake valves 7a and 7b in one cylinder according to the operating state of the internal combustion engine 100. To do. The operation mode of the intake valves 7a and 7b referred to here means a combination of the lift amount, the valve opening period, and the phase.

  FIG. 3 shows operation modes of the intake valves 7a and 7b of the variable valve internal combustion engine of the present embodiment. FIG. 3A shows a distribution example of low to high air volume regions (A) to (D) determined by torque and engine speed. The amount of air (intake air amount) in the present embodiment means the amount of air taken in during one engine cycle.

  Specifically, in the low air amount region (A), as shown in FIG. 3B, the intake valve 7b is set to zero lift, and the lift amount, valve opening period, and phase of the intake valve 7a are variably set. Perform quantity control. In the middle air amount region (B), as shown in FIG. 3 (c), the intake valve 7a is set to zero lift, and the air amount control is performed by variably setting the lift amount, the valve opening period, and the phase of the intake valve 7b. In the high air amount regions (C) and (D), as shown in FIGS. 3D and 3E, the lift amount, the valve opening period and the phase of both the intake valve 7a and the intake valve 7b are variably set. To control the intake air amount.

  In the region (C) where the air amount is relatively small in the high air amount region, the intake air amount is reduced by changing the phase and changing the lift amount and the valve opening period of the intake valve 7b from the full lift state. The lift amount and valve opening period of 7a are increased and the phase is changed so that the difference between the required air amount and the air amount passing through the intake valve 7b is supplied to the combustion chamber 6 through the intake valve 7a.

  In the embodiment shown in FIG. 2, there are two intake valves, but there may be three intake valves. When there are three intake valves, the intake valve with the smallest valve seat diameter may be 7a, and the other two intake valves may be the large intake valve 7b.

  As described above, in the present embodiment, in the low air amount region (A), the intake air amount control is performed only by the small-diameter intake valve 7a, so that each of a plurality of intake valves provided in one cylinder is the same. It is necessary to increase the lift amount and the valve opening period in order to ensure an opening area suitable for the required intake air amount, compared with the case where the intake air amount control is performed by controlling the intake air amount. The opening area referred to here is a port opening area per unit time for each stroke.

  Thereby, as shown in FIG. 4, the variation in the air amount due to the variation in the intake valve lift amount and the valve opening period in the low air amount region (A) can be reduced. This means that since the port diameter of the intake valve 7a is small, the ratio of the variation of the intake air amount to the variation amount of the lift amount and the valve opening period is small. Note that the lift variation amount in FIG. 4 represents variation from the target lift, and the intake air amount variation represents variation from the target air amount.

  In the low air amount region (A) where the intake air amount control is performed only by the intake valve 7a, it is determined by the air amount when the intake valve 7a is at full lift at each engine speed. In the low air amount region (A), the lift provided in the intake valve 7a and the valve opening period may be increased by closing the throttle provided upstream of the intake valve to apply a negative pressure in the intake pipe. This is because the amount of air that fills the intake pipe decreases, and it is necessary to increase the opening area of the intake valve 7a to ensure the amount of air.

  In the middle air amount region (B), since the air amount control is performed only by the intake valve 7b, the intake valve 7b suitable for the required intake air amount is compared with the case where both the intake valve 7a and the intake valve 7b are operated. In order to secure the opening area, it is necessary to expand the lift amount and the valve opening period. Thereby, the variation in the intake air amount due to the variation in the lift amount and the valve opening period of the intake valve 7b in the medium air amount region (B) can be reduced.

  The reason why both the intake valve 7a and the intake valve 7b are not operated in the middle air amount region (B) is that the intake valve 7a is set to zero lift, and the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7a. This is to eliminate the addition of the variation of.

  The middle air amount region (B) in which the intake air amount control is performed only by the intake valve 7b is determined by the air amount when the intake valve 7b is fully lifted at each engine speed.

  In the high air amount regions (C) and (D), both the intake valve 7a and the intake valve 7b are operated to secure the intake air amount. In the region (C) where the air amount is relatively small in the high air amount region, when the lift amount and the valve opening period of the intake valve 7a are increased from zero lift while the lift amount and the valve opening period of the intake valve 7b are maintained at the maximum, Variations in the air amount occur due to variations in the lift amount and valve opening period of the intake valve 7a.

  Therefore, the lift amount and the valve opening period of the intake valve 7a when the lift amount and the valve opening period when the variation in the amount of air passing through the intake valve 7b is within the allowable range depending on the engine speed are determined in advance. In a region (C) where the air amount is relatively small in the air amount region, a predetermined lift amount and valve opening period are given to the intake valve 7a, and the difference in the amount of air passing through the intake valve 7a from the required air amount is taken into the intake air. It can be given by controlling the lift amount, valve opening period and phase of the valve 7b.

  Next, the control at the time of transition in this embodiment is demonstrated using FIG. Depending on the driver's intention, the control unit 13 causes various changes in engine rotation and torque as shown in FIG.

  In the case of changing from the target air amount region (A) to (B) in FIG. 5 (a), first, as shown in FIG. 5 (b), the lift amount and the valve opening period of the intake valve 7a are set. By increasing it, the opening area is increased. When the lift amount and the valve opening period of the intake valve 7a reach the maximum value in configuration and reach the maximum air amount obtained when only the intake valve 7a is operated, the lift amount of the intake valve 7a during the transient change In addition, the valve opening period is decreased, and the lift amount and the valve opening period of the intake valve 7b are increased in synchronization with this to increase the opening area. The target value of the opening area of the intake valve 7b is determined by the target air amount determined from the driver's intention. Finally, the opening area of the intake valve 7a is made zero.

  The reason for performing this control is as follows. If control is performed to increase the opening area of the intake valve 7b while keeping the opening area of the intake valve 7a at the maximum value, it is slightly larger than the maximum air amount obtained when only the intake valve 7a is operated. When the air amount is the target, it is necessary to slightly increase the lift amount and the valve opening period of the intake valve 7b to increase the opening area. Therefore, the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7b Variation occurs.

  Therefore, in the present embodiment, by reducing the opening area of the intake valve 7a, it is necessary to increase the opening area of the intake valve 7b in order to secure the air amount. This control makes it possible to increase the lift amount and the valve opening period of the intake valve 7b, so that variations in the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7b can be reduced.

  Finally, by setting the opening area of the intake valve 7a to zero, it is possible to completely eliminate variations in the intake air amount due to variations in the lift amount and valve opening period of the intake valve 7a. The opening area of the intake valve 7a may not be zero. In that case, the target value of the opening area of the intake valve 7a and the intake valve 7b is determined by the target air amount determined from the driver's intention.

  Further, at the time of a transient change from the low air amount region to the medium air amount region, the intake valve 7a that is operated in the low air amount region is changed according to the operation state before the transient change and the operation state after the transient change intended by the driver. The amount of decrease in the amount of air passing therethrough can also be changed.

  When changing from the target air amount region (B) to (C) in FIG. 5 (a), first, as shown in FIG. 5 (c), the lift amount and the valve opening period of the intake valve 7b are set. By increasing it, the opening area is increased. When the lift amount and the valve opening period of the intake valve 7b reach the maximum value in the configuration and reach the maximum air amount obtained when only the intake valve 7b is operated, the lift amount of the intake valve 7b during the transient change In addition to decreasing the valve opening period, the lift amount and the valve opening period of the intake valve 7a are increased in synchronization with this to increase the opening area. The target value of the opening area of the intake valve 7a and the intake valve 7b is determined by the target air amount determined from the driver's intention.

  The reason for performing this control is as follows. If control is performed to increase the opening area of the intake valve 7a while keeping the opening area of the intake valve 7b at the maximum value, it is slightly larger than the maximum air amount obtained when only the intake valve 7b is operated. When the air amount is the target, it is necessary to slightly increase the lift amount and the valve opening period of the intake valve 7a to increase the opening area. Therefore, the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7a. Variation occurs.

  Therefore, in this embodiment, it is necessary to increase the opening area of the intake valve 7a in order to secure the air amount by reducing the opening area of the intake valve 7b. This control makes it possible to increase the lift amount and the valve opening period of the intake valve 7a, so that variations in the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7a can be reduced. As a result, the deterioration of the control accuracy of the air-fuel ratio of the air-fuel mixture due to the variation in the intake air amount is eliminated, and the engine performance is improved.

  In the case where the target air amount region (C) changes to (D) in FIG. 5 (a), as shown in FIG. 5 (d), the lift amount and valve opening of the intake valve 7a and the intake valve 7b. The opening area is increased by increasing the period. At the time of transition from the target air amount region (C) to (D), the lift amount and the valve opening period of the intake valve 7a and the intake valve 7b can maintain sufficiently large values throughout the transition. It is not necessary to perform intake valve control as in the case of a transient change from (A) to (B) and from the target air amount region (B) to (C). The target value of the opening area of the intake valve 7a and the intake valve 7b is determined by the target air amount determined from the driver's intention.

  At the time of transition from the high air amount region to the low air amount region, conversely to the above control, the intake air amount by the intake valve 7b operated in the middle and high air amount regions is decreased during the transient change, and The intake air amount by the intake valve 7a operated in the low air amount region is increased during the transient change.

  In the present embodiment, since the amount of air passing through the plurality of intake valves 7a and 7b provided in one cylinder varies depending on the engine operating region, each intake valve is operated for each intake valve operation mode shown in the present embodiment. It is necessary to inject an amount of fuel commensurate with the amount of air passing through the valve. As shown in FIG. 6, it is ideal to provide the fuel injection valve 12 individually for each of the plurality of intake ports 11a and 11b arranged in one cylinder.

(Embodiment 2)
Next, Embodiment 2 of the variable valve operating internal combustion engine according to the present invention will be described. The overall configuration of the variable valve internal combustion engine of the present embodiment is the same as that shown in FIG. 1, and in this embodiment, the valve seat diameters of the intake valves 7c and 7d provided in one cylinder. Are configured to be equal to each other. FIG. 7 shows the cylinder head 5 viewed from the piston 4 side.

  In this embodiment, an intake valve 7c used in the low air amount region and an intake valve 7) used in the high air amount region are used. Further, the operation mode of each of the intake valves 7c and 7d provided in one cylinder is changed depending on the operation region of the engine. Also in this embodiment, the operation mode of the intake valve means a combination of the lift amount, the valve opening period, and the phase.

  Specifically, as shown in FIG. 8, in the low air amount region (A), as shown in FIG. 8B, the intake valve 7d is set to zero lift, and the lift amount, valve opening period and phase of the intake valve 7 are set. The air amount is controlled by controlling. In the high air amount regions (C) and (D), as shown in FIGS. 8C and 8D, by controlling the lift amount, valve opening period and phase of both the intake valve 7 and the intake valve 7d. Perform intake air volume control. FIG. 8A shows a distribution example of the low to high air amount regions (A), (C), and (D) determined by the torque and the engine speed.

  In the region (C) where the air amount is relatively small in the high air amount region, the lift amount and the valve opening period of the intake valve 7c are reduced and the phase is changed to reduce the amount of air passing therethrough and the lift of the intake valve 7d. The amount and the valve opening period are increased and the phase is changed so that the difference between the required air amount and the air amount passing through the intake valve 7 is supplied to the combustion chamber through the intake valve 7d.

  Note that the amount of air in the present embodiment means the amount of air sucked during one cycle. In FIG. 7, the number of intake valves is two. However, the number of intake valves may be three. When there are three intake valves, the intake valve 7c used in the low air amount region and the other intake valves 7d are used.

  As described above, also in the present embodiment, since the air amount control is performed only by the intake valve 7c in the low air amount region (A), each of the plurality of intake valves provided in one cylinder is similarly controlled to control the air amount. Compared to the case where the amount control is performed, it is necessary to expand the lift amount and the valve opening period in order to ensure an opening area suitable for the required intake air amount. Thereby, as shown in FIG. 4, the variation in the air amount due to the variation in the intake valve lift amount and the valve opening period in the low air amount region can be reduced. As a result, the deterioration of the control accuracy of the air-fuel ratio of the air-fuel mixture due to the variation in the intake air amount is eliminated, and the engine performance is improved.

  The low air amount region (A) where the intake air amount control is performed only by the intake valve 7c is determined by the air amount when the intake valve 7c is at full lift at each engine speed. In the low air volume region (A), the lift amount and the valve opening period of the intake valve 7c may be increased by closing the throttle provided upstream of the intake valve to apply a negative pressure in the intake pipe. This is because the amount of air that fills the intake pipe decreases, and it is necessary to increase the opening area of the intake valve 7c to ensure the amount of air.

  In the high air amount region, both the intake valve 7c and the intake valve 7d are operated to secure the intake air amount. In the region (C) where the air amount is relatively small in the high air amount region, when the lift amount and the valve opening period of the intake valve 7d are increased from zero lift while the lift amount and the valve opening period of the intake valve 7c are maintained at the maximum, Variations in the air amount occur due to variations in the lift amount and valve opening period of the intake valve 7d.

  Therefore, the lift amount and the valve opening period of the intake valve 7c when the lift amount and the valve opening period when the variation in the amount of air passing through the intake valve 7d is within the allowable range depending on the engine speed are determined in advance. In a region (C) where the air amount is relatively small in the air amount region, a predetermined lift amount and valve opening period are given to the intake valve 7c, and the difference between the required air amount and the amount of air passing through the intake valve 7c is determined as the intake valve. It can be given by controlling the lift, valve opening period and phase of 7d.

  Next, the control at the time of transition in this embodiment is demonstrated using FIG. Depending on the driver's intention, the control unit 13 causes various changes in engine rotation and torque as shown in FIG. 9A.

  In the case where a transient change is made from the target air amount region (A) to (C) in FIG. 9 (a), as shown in FIG. 9 (b), first, the lift amount and the valve opening period of the intake valve 7c. Increase the opening area. When the lift amount and the valve opening period of the intake valve 7c reach the maximum value in configuration and reach the maximum air amount obtained when only the intake valve 7c is operated, the lift amount of the intake valve 7c during the transient change In addition to decreasing the valve opening period, the lift amount and the valve opening period of the intake valve 7d are increased in synchronization with this to increase the opening area. The target value of the opening area of the intake valve 7 and the intake valve 7d is determined by the target air amount determined from the driver's intention.

  The reason for performing this control is as follows. If the control is performed so that the opening area of the intake valve 7d is increased while the opening area of the intake valve 7c is maintained at the maximum value, it is slightly larger than the maximum air amount obtained when only the intake valve 7c is operated. When the air amount is the target, it is necessary to slightly increase the lift amount and the valve opening period of the intake valve 7d to increase the opening area. Therefore, the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7d Variation occurs.

  Therefore, in this embodiment, it is necessary to increase the opening area of the intake valve 7d in order to secure the air amount by reducing the opening area of the intake valve 7c. This control makes it possible to increase the lift amount and the valve opening period of the intake valve 7d, so that variations in the intake air amount due to variations in the lift amount and the valve opening period of the intake valve 7d can be reduced. As a result, the deterioration of the control accuracy of the air-fuel ratio of the air-fuel mixture due to the variation in the intake air amount is eliminated, and the engine performance is improved.

  Further, at the time of a transient change from the low air amount region to the high air amount region, the intake valve 7c that is operated in the low air amount region is changed according to the operation state before the transient change and the operation state after the transient change intended by the driver. The amount of decrease in the amount of air passing therethrough can also be changed.

  In the case where the target air amount region (C) is changed to (D) in FIG. 9 (a), as shown in FIG. 9 (c), the lift amount and valve opening of the intake valve 7c and the intake valve 7d are opened. The opening area is increased by increasing the period. At the time of transition from the target air amount region (C) to (D), the lift amount and the valve opening period of the intake valve 7c and the intake valve 7d can be maintained at sufficiently large values throughout the transition. There is no need to perform intake valve control as in the transitional change from (A) to (C). The target value of the opening area of the intake valve 7c and the intake valve 7d is determined by the target air amount determined from the driver's intention.

  In this embodiment as well, during the transition from the high air amount region to the low air amount region, the intake air amount by the intake valve 7d operated in the middle and high air amount regions is changing transiently, contrary to the above control. The intake air amount by the intake valve 7c operated in the low air amount region is increased during the transient change.

  In the present embodiment, the amount of air passing through the intake valves 7c and 7d provided in one cylinder varies depending on the engine operating region. Therefore, the intake air for each operation mode of the intake valves 7c and 7d shown in the present embodiment is different. It is necessary to inject an amount of fuel commensurate with the amount of air passing through the valve. Therefore, in this case as well, as shown in FIG. 6, it is ideal to provide the fuel injection valve 12 for each intake port arranged in one cylinder.

1 is a system diagram of a variable valve internal combustion engine according to a first embodiment of the present invention. The figure which shows the structure of the intake valve seat diameter of the variable valve-actuated internal combustion engine of FIG. The figure which shows the operation mode of the intake valve by the driving | running state of the variable valve internal combustion engine of FIG. The figure which shows the reduction effect of the dispersion | variation in the air quantity by the dispersion | variation in the intake valve lift amount and valve opening period of 1st and 2nd embodiment of this invention. The figure which shows the control method of the intake valve operation | movement at the time of the transition of 1st Embodiment of this invention. The figure which shows arrangement | positioning of the fuel injection valve of the variable valve operating internal combustion engine of 1st and 2nd embodiment of this invention. The figure which shows the structure of the intake valve seat diameter of 2nd Embodiment of this invention. The figure which shows the operation mode of the intake valve by the driving | running state of the variable valve operating internal combustion engine of 2nd Embodiment of FIG. The figure which shows the control method of the intake valve operation | movement at the time of the transition of 2nd Embodiment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Internal combustion engine 1 Cylinder block 2 Connecting rod 3 Cylinder 4 Piston 5 Cylinder head 6 Combustion chamber 7 (7a, 7b, 7c, 7d) Intake valve 8 Exhaust valve 9 Spark plug 10 Variable valve mechanism 11 (11a, 11b) Intake port 12 Fuel injection valve

Claims (5)

Each cylinder has a plurality of intake ports and an intake valve that individually opens and closes each intake port, and at least one of the lift amount and the valve opening period of the intake valve is continuously variably set. In a variable valve operating internal combustion engine that includes a valve mechanism and controls the amount of intake air by the intake valve,
The plurality of intake valves that individually open and close the plurality of intake ports include a first intake valve and a second intake valve,
In the control mode of the high air amount region where the air amount is the largest during the control mode of the plurality of intake valves based on the intake air amount, the low air amount region obtained by dividing the high air amount region into two by the air amount Then, by operating the lift amount or valve opening period and phase of the second intake valve, the amount of air passing through the second intake valve is changed from the required amount of air to the amount of air passing through the first intake valve. A control apparatus for a variable valve operating internal combustion engine, characterized in that control is performed so as to obtain a difference obtained by subtracting. The control apparatus for a variable valve operating internal combustion engine according to claim 1,
The first intake valve is given a predetermined lift amount and a valve opening period,
The difference is obtained by subtracting the amount of air passing through the first intake valve when the predetermined lift amount and the valve opening period are given from the required air amount. Control device for an internal combustion engine. Each cylinder has a plurality of intake ports and an intake valve that individually opens and closes each intake port, and at least one of the lift amount and the valve opening period of the intake valve is continuously variably set. In a variable valve operating internal combustion engine that includes a valve mechanism and controls the amount of intake air by the intake valve,
The plurality of intake valves that individually open and close the plurality of intake ports include a first intake valve and a second intake valve having a valve seat diameter larger than the first intake valve,
The control of the intake air amount is as follows:
A first mode in which the air amount is controlled only by the first intake valve;
A second mode in which the amount of air is controlled only by the second intake valve;
A predetermined lift amount and valve opening period are given to the first intake valve, and the lift amount or valve opening period and phase of the second intake valve are manipulated to pass through the second intake valve. A third mode for controlling the air amount to be a difference obtained by subtracting the amount of air passing through the first intake valve from the required air amount;
A fourth mode of controlling the air amount with the first intake valve while maintaining the lift amount and the valve opening period of the second intake valve to the maximum;
A control apparatus for a variable valve operating internal combustion engine, comprising: In the control apparatus for a variable valve operating internal combustion engine according to claim 3,
When the lift amount and the valve opening period of the first intake valve reach the maximum during the transition period during which the first mode is switched to the second mode, the opening area of the first intake valve is reduced. A control apparatus for a variable valve operating internal combustion engine, wherein the opening area of the second intake valve is increased in synchronization. In the control apparatus for a variable valve operating internal combustion engine according to claim 3 or 4,
When the lift amount and the valve opening period of the second intake valve reach the maximum during the transition period from the second mode to the third mode, the opening area of the second intake valve is reduced. A control apparatus for a variable valve operating internal combustion engine, wherein the opening area of the first intake valve is increased synchronously.

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