JP2002213260A - Valve drive device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and rapidly output torque equivalent to the required load for an internal combustion engine. SOLUTION: This device is provided with a valve 3 for opening and closing an opening communicating with a combustion chamber 6 of the internal combustion engine, and opening degree changing mechanism 30 for changing the opening degree of the valve, and an opening timing changing mechanism for changing the opening timing of the valve. The target opening degree of the valve is set according to the required output of the internal combustion engine. The target opening timing of the valve is set according to the required output of the internal combustion engine. When the change rate of the required load is larger than a predetermined value while the target opening degree is not changed, the target opening degree is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a valve driving device for an internal combustion engine.

[0002]

2. Description of the Related Art There are various demands for an internal combustion engine, such as improvement of fuel consumption, reduction of exhaust emission, and improvement of output. A technique for changing the opening degree and the opening timing of an intake valve in order to optimize the operation of an internal combustion engine to meet these demands is known. This technology is disclosed in, for example,
-235305. According to the technique disclosed in the publication, the opening degree and the opening timing of the intake valve are changed in accordance with the required load of the internal combustion engine and the engine speed to optimize the operation of the internal combustion engine.

[0003]

The load required when the change rate of the required load of the internal combustion engine is relatively large, that is, the amount of air taken into the combustion chamber of the internal combustion engine in order to output torque. Need to be increased at a relatively large rate. However, the above publication is not designed to change the opening degree and the opening timing of the intake valve according to the change rate of the required load of the internal combustion engine. For this reason, according to the above-mentioned publication, only the valve opening timing may be changed in spite of the fact that the change rate of the required load of the internal combustion engine is relatively large and the intake air amount should be increased at a relatively large rate.

However, in the above publication, to change the valve opening timing, it is necessary to rotate the camshaft so that the rotation phase changes. If the valve opening timing is changed by using this method, the camshaft must be rotated until the target valve opening timing is reached. Takes some time. For this reason, even if the valve opening timing is changed, the intake air amount cannot be increased at a large rate, and the torque corresponding to the required load of the internal combustion engine cannot be output reliably and quickly. This is also a problem that occurs in an internal combustion engine in which the amount of intake air can be changed by changing the opening degree and opening timing of the exhaust valve. Therefore, an object of the present invention is to enable a torque corresponding to a required load of an internal combustion engine to be output reliably and quickly.

[0005]

According to a first aspect of the present invention, there is provided a valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, and for changing a valve opening degree of the valve. Opening degree changing mechanism, opening degree setting means for setting a target opening degree of the valve according to the required output of the internal combustion engine, and a valve opening timing changing mechanism for changing the opening timing of the valve And a valve driving device for an internal combustion engine, comprising: valve opening timing setting means for setting the valve opening timing of the valve according to the required output of the internal combustion engine. When the target valve opening degree is large but not changed, the target valve opening degree is increased. That is, the opening degree of the valve is controlled based on the change rate of the required load.

According to a second invention, in the first invention, a throttle valve for shutting off an intake passage of the internal combustion engine is provided, and a change rate of a required load of the internal combustion engine is larger than a predetermined change rate. When the value is a negative value but the target valve opening degree is not changed, the target valve opening degree is increased and the throttle valve is closed. According to a third aspect, in the first aspect, the target timing is set according to the target valve opening degree and the required output of the internal combustion engine.

According to a fourth aspect of the present invention, there is provided a valve for opening / closing an opening communicating with a combustion chamber of an internal combustion engine, and a valve opening characteristic changing mechanism for changing the valve opening characteristic of the valve. And a valve opening characteristic setting means for setting a target valve opening characteristic in accordance with the required output of the internal combustion engine, wherein the valve opening characteristic changing mechanism is driven so that the valve opening characteristic becomes the target valve opening characteristic. In the valve drive device for an internal combustion engine, the lower limit value for the amount of air sucked into the combustion chamber is set based on the responsiveness of the valve opening characteristic changing mechanism, and the air sucked into the combustion chamber during engine operation Is maintained above the lower limit. That is, according to this, even if the intake air amount is reduced by changing the valve opening characteristic of the valve, the intake air amount is maintained at a value higher than the lower limit determined according to the response factor of the valve opening characteristic changing mechanism. .

According to a fifth aspect of the present invention, there is provided a valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, and a valve opening characteristic changing mechanism for changing the valve opening characteristic of the valve. And a valve opening characteristic setting means for setting a target valve opening characteristic in accordance with the required output of the internal combustion engine, wherein the valve opening characteristic changing mechanism is driven so that the valve opening characteristic becomes the target valve opening characteristic. In the valve drive device for an internal combustion engine, the lower limit value of the amount of air taken into the combustion chamber is set based on the operating speed of the valve opening characteristic changing mechanism, and the amount of air taken into the combustion chamber during engine operation Is maintained at or above the lower limit. That is, according to this, even if the intake air amount is reduced by changing the valve opening characteristic of the valve, the intake air amount is maintained at a value higher than the lower limit determined according to the operation speed of the valve opening characteristic changing mechanism.

According to a sixth aspect, in the fifth aspect, the lower limit is set to be larger as the operation speed of the valve opening characteristic changing mechanism is lower. According to a seventh aspect, in the fifth or sixth aspect, the operating speed of the valve opening characteristic changing mechanism is measured when the engine is decelerated. According to an eighth aspect of the present invention, there is provided a valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, a valve opening characteristic changing mechanism for changing a valve opening characteristic of the valve, and an internal combustion engine. Valve opening characteristic setting means for setting the target valve opening characteristic according to the required output of the engine,
In a valve driving device for an internal combustion engine configured to drive a valve opening characteristic changing mechanism so that a valve opening characteristic becomes a target valve opening characteristic,
The target valve opening characteristic set by the valve opening characteristic setting means is changed so that the amount of air sucked into the combustion chamber at the time of engine operation start is increased. That is, at the time of starting the operation of the engine, a larger amount of air than the amount determined according to the required output is sucked into the combustion chamber. According to a ninth aspect of the present invention, there is provided a valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, and a valve opening characteristic setting unit for changing a valve opening characteristic of the valve. In the valve driving device for an internal combustion engine, which drives the valve opening characteristic changing mechanism so that the valve opening characteristic becomes the target valve opening characteristic, when the required output change rate is larger than a predetermined value, the valve passes through the opening. The target valve opening characteristic set by the valve opening characteristic setting means is corrected so that the flow rate of the fluid to be increased is increased. In order to solve the above problems, in a tenth invention, a valve for opening and closing an opening leading to a combustion chamber of an internal combustion engine, a valve opening degree changing means for changing the valve opening degree of the valve, And a target valve opening degree setting means for setting a target valve opening degree of the valve in accordance with the required output. In the valve drive device for an internal combustion engine, when the change rate of the required load is larger than a predetermined value, the valve opening is performed. The target valve opening degree set by the degree changing means is increased.

According to a tenth aspect of the present invention, there is provided a valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, and changing a valve opening characteristic for changing the valve opening characteristic of the valve. A valve opening characteristic setting means for setting a target valve opening characteristic in accordance with a required output of the internal combustion engine, and driving the valve opening characteristic changing mechanism such that the valve opening characteristic becomes the target valve opening characteristic. In such a valve drive device for an internal combustion engine, when the change rate of the required output is larger than a predetermined value, the control amount for driving the valve opening characteristic changing mechanism is increased.

According to a twelfth aspect, in the tenth aspect, the valve opening characteristic changing mechanism changes a valve opening degree changing mechanism for changing a valve opening degree and a valve opening timing. For changing the valve opening timing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. First, an overall configuration of an internal combustion engine provided with the variable valve apparatus of the present invention will be described with reference to FIG. The internal combustion engine shown in FIG. 1 is a so-called four-cycle gasoline engine. In FIG. 1, 1 is an engine body, 2 is an intake port, 3 is an intake valve, 4 is an exhaust port, 5 is an exhaust valve,
6 is a combustion chamber, 7 is a spark plug. A piston 8 is arranged in the combustion chamber 6. The intake valve 3 is driven to open and close by an intake valve driving device described later.

The intake port 2 is connected to an intake manifold 9. The intake manifold 9 is connected to an intake passage 11 via a surge tank 10. The engine body 1 is located in the intake passage 11.
A mass flow rate detector 12 for detecting a mass flow rate of air to be sucked into the air (hereinafter, an intake air amount) is disposed. An air cleaner 13 is connected to the intake passage 5 on the upstream side of the mass flow detector 12. On the other hand, a throttle valve 15, which is normally fully opened, is disposed in the intake passage 5 on the downstream side. A fuel injection valve 16 is attached to the intake manifold 9 downstream of the throttle valve 15 and near the intake port 2. The fuel injection valve 16 is connected to a fuel tank 18 via a fuel supply passage 17. A fuel pump 19 having a variable discharge amount is disposed in the fuel supply passage 17. The exhaust port 4 is connected to an exhaust manifold 20. The exhaust manifold 20 is connected to an exhaust passage 21.

The engine body 1 includes an ignition distributor 25.
Is attached. Two crank angle sensors 26 and 27 are attached to the ignition distributor 25. These crank angle sensors 26 and 27 generate a pulse signal for each predetermined rotation of an engine crankshaft (not shown). The crank angle sensor 26 outputs a pulse signal for detecting a reference position every time the engine stroke in the specific combustion chamber 6 reaches the compression top dead center, ie, every time the engine crankshaft rotates 720 °. On the other hand, the crank angle sensor 27 outputs a pulse signal for detecting a crank rotation angle every time the engine crankshaft rotates 30 °. The engine speed is calculated based on the reference position detection pulse signal and the crank rotation angle detection pulse signal.

The internal combustion engine has an electronic control unit 50.
The electronic control unit 50 is composed of a digital computer, and a ROM (read only memory) 52, a RAM (random access memory) 53, a CPU (microprocessor) 54, an input port 55, and an output port 56 connected to each other by a bidirectional bus 51. Is provided. The mass flow detector 12 is connected to the input port 55 via the corresponding AD converter 57. Therefore, these outputs are input to the input port 55 via the corresponding AD converter 57.
Also, the crank angle sensors 26 and 27 are connected to the input port 55
Directly connected to Therefore, these pulse signals are directly input to input port 55.

The ignition plug 7, the fuel injection valve 16 and the fuel pump 19 are connected to an output port 56 via a corresponding drive circuit 58.
Connected to. Therefore, these operations are controlled by the electronic control unit 50 according to the engine request. A load sensor 28 is connected to the accelerator pedal 14. The load sensor 28 detects a required load on the internal combustion engine. The load sensor 28 is connected to the input port 55 via the corresponding AD converter 57. Therefore, the output from the load sensor 28 is input to the input port 55 via the AD converter 57.

Next, the configuration of the intake valve driving device of the present embodiment will be described with reference to FIG. The intake valve driving device includes a cam mechanism for opening and closing the intake valve 3. The cam mechanism has a lift amount changing mechanism 30. The lift amount changing mechanism 30 of the present embodiment can change the lift amount of the intake valve 3, that is, the degree of opening, and the operating angle, that is, the opening period of the intake valve 3 (the opening period of the intake valve). The lift amount changing mechanism 30 has three cams 32a, 32b, 32c and three lift arms 33a, 33b, 33c corresponding thereto. The cams 32a, 32b, 32c are mounted on a common camshaft 34. Further, the amount by which each of the cams 32a, 32b, 32c lifts the intake valve 3, that is, the opening degree and the period during which the intake valve 3 is opened, that is, the intake valve opening period, are different from each other. In this embodiment, the lift amount of the central cam 32a is the smallest and the intake valve opening period is the shortest, and the lift amount of the left cam 32b of the central cam 32a in FIG. Then, shortly, the lift amount of the cam 32c on the right side of the center cam 32a in FIG. 2 is the largest and the intake valve open period is the longest. In the following description, the center cam 32a is referred to as a small cam, the left cam 32b is referred to as a middle cam, and the right cam 32c is referred to as a large cam for convenience. In the lift amount changing mechanism of the present embodiment, the lift amount of the intake valve 3 and the opening period of the intake valve are simultaneously changed by switching the cam that substantially functions to lift the intake valve 3. , The lift amount includes the intake valve open period. Of course, it is within the scope of the present invention to use a mechanism that changes only the lift amount or only the intake valve opening period instead of the lift amount change mechanism of the present embodiment.

The lift arms 33a, 33b, 33c are pivotally mounted on a common arm shaft 35.
The central lift arm 33a is pivoted by the small cam 32a. The lift arm 33a at the center as viewed in FIG.
The left lift arm 33b is pivoted by the middle cam 32b. The lift arm 33 at the center as seen in FIG.
The lift arm 33c on the right side of a is pivoted by the large cam 32c. In the following description, for convenience, the central lift arm 33a is referred to as a small lift arm, the left lift arm 33b is referred to as a middle lift arm, and the right lift arm 33c is referred to as a large lift arm. In this embodiment, the small lift arm 33a contacts the intake valve 3 to open the intake valve 3.

As shown in FIG. 3, the small lift arm 33a
Is formed with one through hole 36 at one end. Through hole 36
Extends in the lateral direction of the small lift arm 33a. A hydraulic chamber 37b is formed at one end of the middle lift arm 33b. A pin 38b is slidably housed in the hydraulic chamber 37b. The pin 38b is urged by a coil spring 39b. A hydraulic chamber 37c is also formed at one end of the large lift arm 33c.
A pin 38c is slidably housed in the hydraulic chamber 37c. The pin 38c is urged by a coil spring 39c.

The two hydraulic chambers 37b and 37c are connected to a hydraulic line 42.
Is connected to the oil pan 41 via the. Hydraulic line 42
A switching valve 40 and an oil pump 49 are disposed in the first position. The oil pump 49 can selectively introduce engine oil into one of the two hydraulic chambers 37b and 37c by switching the switching valve 40. The oil pump 49 and the switching valve 40 are connected to the output port 56 via the corresponding drive circuit 58, and the operation thereof is controlled by the electronic control unit 50.

The cam mechanism further includes a lift timing changing mechanism 31. The lift timing changing mechanism 31 can change the lift timing of the intake valve 3, that is, the valve opening timing. Lift timing change mechanism 31
Has a rotor 43 and a housing 44. Rotor 43
Is rotatably accommodated in the housing 44 within a certain range. The rotor 43 is non-rotatably attached to the camshaft 34.

As shown in FIG. 4, the rotor 43 has four blades 45 extending radially outward. These blades 45 are equally spaced along the circumferential direction of the rotor 43. On the other hand, the housing 44 has four partition walls 46 extending radially inward. These partitions 46 are equally spaced along the circumferential direction of the housing 44. Rotor 43
Is accommodated in the housing 44, the blades 4 of the rotor 43
8 and the partition 46 of the housing 44
a and 46b are formed. These compartments function alternately as advancing compartments 46a or retarding compartments 46b along the circumferential direction.

The compartments 46a and 46b are connected to the hydraulic line 4
2 and connected to an oil pan 41. Hydraulic line 4
2 is provided with a switching valve 48 and an oil pump 49.
By switching the switching valve 48, the oil pump 49 can selectively introduce the engine oil into one of the advance compartment 46a and the retard compartment 46b.
The switching valve 48 is connected to the output port 55 via the corresponding drive circuit 58, and its operation is controlled by the electronic control unit 50.

The housing 44 is a gear, and engages with a gear 60 rotated by the output of the internal combustion engine as shown in FIG. Therefore, the housing 44 is rotated by the output of the internal combustion engine, and the rotation of the housing 44 is transmitted to the rotor 43 via the engine oil in the compartments 46a and 46b. Thus, the cams 32a, 32b, 3
2c is rotated.

Next, the operation of the lift amount changing mechanism will be described.
When the engine oil is introduced into the hydraulic chambers 37b, 37c, the pins 38b, 38c are pressed against the urging force of the coil springs 39b, 39c by the pressure of the engine oil, and the hydraulic chamber 3
7b and 37c, and finally engages with the through hole 36 of the small lift arm 33a. Of course, when the engine oil is not introduced into any of the hydraulic chambers 37b and 37c, both the pins 38b and 38c remain housed in the hydraulic chambers 37b and 37c, respectively.

When engine oil is not introduced into any of the hydraulic chambers 37b and 37c, the small lift arm 3
3a is driven by the small cam 32a. Therefore, at this time, the lift amount of the intake valve 3 is relatively small, so that the amount of air sucked into the combustion chamber 6 (intake amount) is relatively small. When engine oil is introduced into the hydraulic chamber 37b of the middle lift arm 33b, the small lift arm 33a
Is reciprocated by the middle cam 32b together with the middle lift arm 33b. Accordingly, the lift amount of the intake valve 3 at this time is medium, so the intake amount is medium. When engine oil is introduced into the hydraulic chamber 37c of the large lift arm 33c, the small lift arm 33a is reciprocated by the large cam 32c together with the large lift arm 33c. Therefore, the lift amount of the intake valve 3 at this time is relatively large, so that the intake amount is relatively large.

It should be noted that whether or not engine oil should be introduced into the hydraulic chambers 37b, 37c, and which hydraulic chamber 37b, 37c
Whether the engine oil should be introduced into 37c will be described in connection with the operation control of the internal combustion engine described later. Next, the operation of the lift timing changing mechanism will be described. Advancement compartment 46
When the engine oil is introduced into a or the retarding chamber 46b, the rotor 43 is rotated relative to the housing 44 by the pressure of the engine oil. When the engine oil is introduced into the advance compartment 46a, the rotor 43 is rotated relative to the housing 44 so that the lift timing of the intake valve 3 by the cams 32a, 32b, 32c is advanced. On the other hand, retard cell 4
When the engine oil is introduced into 6b, the cam 32
The rotor 43 is relatively rotated with respect to the housing 44 so that the lift timing of the intake valve 3 by a, 32b, and 32c is delayed.

It should be noted that whether or not engine oil should be introduced into the compartments 46a, 46b, and which compartment 46a, 46b
Whether engine oil should be introduced to b will be described in connection with the next operation control of the internal combustion engine. Next, the operation control of the internal combustion engine in this embodiment will be described. Elements to be controlled in the operation control of the internal combustion engine include, for example, the amount of fuel injected from the fuel injection valve 16 (hereinafter, referred to as fuel injection amount), the timing of actually injecting fuel from the fuel injection valve 16 (hereinafter, fuel injection timing). ), The timing at which fuel is ignited by the ignition plug 7 (hereinafter, ignition timing), the lift amount of the intake valve 3, the opening degree of the throttle valve 15, and the lift timing of the intake valve 3. Although the fuel injection timing and the ignition timing may be changed according to the operating state of the internal combustion engine, in the present embodiment, they are constant regardless of the operating state of the internal combustion engine. Accordingly, control of the remaining fuel injection amount, the lift amount of the intake valve 3, the opening degree of the throttle valve 15, and the lift timing of the intake valve 3 will be described below.

First, control of the fuel injection amount will be described. According to the present embodiment, the mass flow rate detector 12 detects the amount of air sucked into the combustion chamber 6 per unit engine speed (intake amount), and detects the amount of air so that the air-fuel ratio becomes the target air-fuel ratio. Inject the appropriate amount of fuel. The target air-fuel ratio in this embodiment is a stoichiometric air-fuel ratio. Next, control of the opening of the throttle valve 15 will be described. In this embodiment, the opening of the throttle valve 15 is usually set to the maximum. That is, the throttle valve 15 is normally fully opened. Therefore, in this embodiment, the intake air amount
It is not controlled by adjusting the opening of the
The control is performed by changing the lift amount and the lift timing of the intake valve 3 as described later.

Next, the control of the lift amount of the intake valve 3 and the control of the lift timing will be described together. Although the details will be described later, in the present embodiment, the lift amount is roughly determined based on the engine speed and the required load if the change rate of the required load is smaller than a predetermined ratio, that is, based on the required output, and the lift amount is determined. Is larger than a predetermined ratio, it is determined based on the change rate of the required load regardless of the engine speed and the required load. On the other hand, the lift timing is based on the engine speed and the required load using a map determined for each lift amount determined based on the engine speed and the required load when the required load change rate is smaller than a predetermined ratio. That is, it is determined based on the required output. That is, the lift timing is determined based on the lift amount and the required output regardless of the required load change rate. Then, the lift amount changing mechanism 30 and the lift timing changing mechanism 31 are driven to obtain the lift amount and the lift timing determined in this way.

Normally, when the rate of change of the required load is large, it is necessary to greatly change the intake air amount. However, when the system is configured so that only the lift timing is changed when the change rate of the required load is large, the intake air amount cannot be largely changed following the change of the required load. This is because, in the lift timing changing mechanism as in the present embodiment, it takes time until the lift timing reaches the target lift timing. On the other hand, according to the lift amount changing mechanism of the present embodiment, the lift amount can be changed quickly. Therefore, if the lift amount is intentionally changed when the change rate of the required load is large as in the present embodiment, the intake air amount can be changed greatly following the change in the required load. Also, while the lift amount is changed and the intake air amount is greatly changed as in the present embodiment, the target lift timing is set regardless of the required load change rate, and the lift timing is changed so that the lift timing becomes the target lift timing. If the mechanism is driven, when the change rate of the required load becomes small, the lift amount is set to the lift amount determined by the engine speed and the required load. Obtainable. Thus, the torque corresponding to the required load of the internal combustion engine can be output reliably and quickly.

Next, the procedure for setting the target lift amount and the procedure for setting the target lift timing will be described in detail. According to the present embodiment, the target lift amount is initially set according to the required load change rate per unit time (hereinafter simply referred to as the required load change rate) dL / dt and the required load L as shown in FIG. Follow the determined control. That is, when the required load change rate dL / dt is a relatively small positive value and the required load L is a positive value, the target lift amount is set according to the first control A, and the required load change rate dL / dt is set to a medium value. When the required load L is a positive value and the required load L is a positive value, according to the second control B, the required load change rate dL / dt is a relatively large positive value and the required load L is a positive value. Sometimes the third control C
Obey.

The target lift amount is set according to the first control A when the required load change rate dL / dt is a relatively small negative value and the required load L is a positive value. Even when dt is a relatively small value and the required load L is a negative value, according to the first control A, the required load change rate dL / dt is a moderate negative value and the required load L is positive. The fourth control D is performed when the value is Further, when the required load change rate dL / dt is a moderate negative value and the required load L is a negative value, the target lift amount is set according to the second control B, and the required load change rate dL / dt is compared. When the required load L is a positive value and the required load L is a positive value, according to the fifth control E, the required load change rate dL / dt is a relatively large negative value and the required load L is a negative value. In some cases, the third control C is followed.

In the first control A, the setting of the target lift amount follows the control determined according to the engine speed Ne and the required load L as shown in FIG. That is, when the engine output calculated from the engine speed Ne and the required load L is relatively small, the setting of the target lift amount follows the sixth control S. According to the sixth control S, the target lift amount is set relatively small,
At this time, the lift amount changing mechanism 30 is
3b hydraulic chamber 37b and large lift arm 33c hydraulic chamber 3
No engine oil is introduced into any of 7c. Therefore, since the cam for reciprocating the small lift arm 33a is the small cam 32a, the intake amount is relatively small. A target lift timing is set based on the engine speed Ne and the required load L from a map as shown in FIG. 7 determined according to the target lift amount set in this way, and the lift is set in accordance with the target lift timing. The timing change mechanism 31 is driven. Since the output performance and exhaust emission of the internal combustion engine are determined according to the lift timing, the map of FIG. 7 is formed in consideration of these circumstances. According to the map shown in FIG. 7, the engine oil is introduced into the retardation compartment 46b so that the target lift timing is delayed as the engine speed Ne increases. Further, the engine oil is introduced into the advance compartment 46a so that the target lift timing is earlier as the required load L is larger.

When the engine output is moderate, the target lift follows the seventh control M. According to the seventh control M, the target lift amount is set to a medium level, and at this time, the lift amount changing mechanism 30 operates the hydraulic chamber 37b of the medium lift arm 33b.
Let the engine oil be introduced to the engine. Therefore, the cam for reciprocating the small lift arm 33a is substantially the middle cam 32b.
Therefore, the intake air amount is medium. The target lift timing is determined based on the engine speed Ne and the required load L from a map as shown in FIG. 7 which is determined according to the target lift amount set in this way. The timing change mechanism 31 is driven.

Further, when the engine output is relatively large, the target lift follows the eighth control L. According to the eighth control L, the target lift amount is set relatively large. At this time, the lift amount changing mechanism 30 causes the engine oil to be introduced into the hydraulic chamber 37c of the large lift arm 33c. Therefore, since the cam for reciprocating the small lift arm 33a is substantially the large cam 32c, the intake air amount is relatively large. The target lift timing is determined based on the engine speed Ne and the required load L from a map as shown in FIG. 7 which is determined according to the target lift amount set in this way. The timing change mechanism 31 is driven.

As described above, the required load change rate dL / dt
Is a medium positive value, the target lift amount is set according to the second control B, and the target lift amount is increased by this control. Therefore, the lift amount changing mechanism 30 changes the cam to be operated from the current cam to the cam having the larger lift amount. That is, if the currently functioning cam is the small cam 32a, the lift amount changing mechanism 30 changes the functioning cam from the small cam 32a to the medium cam 32b, and if the currently functioning cam is the medium cam 32b. The cam to be operated is changed from the middle cam 32b to the large cam 32c. As described above, when the required load change rate dL / dt is a medium positive value, the intake air amount needs to be increased relatively large in order to increase the output torque following the increase in the required load L. According to the second control B, the target lift amount is relatively increased, and the intake air amount is also increased relatively. Therefore, a torque that follows a change in the required load can be output. Note that even when the second control B is executed, the target lift timing is shown in FIG. 7 corresponding to the controls S, M, and L determined based on the engine speed Ne and the required load L shown in FIG. Is set from such a map. Although the description is omitted below, the target lift timing is similarly set when the second control B, the third control C, the fourth control D, and the fifth control E are executed, as shown in FIG. It is set from a map as shown in FIG. 7 corresponding to control determined based on the rotation speed Ne and the required load L.

As described above, the required load change rate dL / dt
Is a relatively large positive value, the target lift amount is set according to the third control C. According to this control, the target lift amount is maximized. Therefore, the lift amount changing mechanism 30 changes the cam to be operated from the current cam to the large cam 32.
Change to c. That is, the lift amount changing mechanism 30 is
Even if the functioning cam is the small cam 32a, the middle cam 32
Even in the case of b, this cam is changed to the large cam 32c. As described above, when the required load change rate dL / dt is a relatively large positive value, the intake air amount needs to be largely increased in order to increase the output torque following the increase in the required load L. According to the third control C, the target lift amount is greatly increased, and the intake air amount is also greatly increased. Therefore, a torque that follows a change in the required load can be output.

As described above, the required load change rate dL / dt
Is a moderate negative value and the required load L is a positive value, the target lift amount is set according to the fourth control D, and the target lift amount is reduced by the control. Accordingly, the lift amount changing mechanism 30 changes the cam to be operated from the current cam to a cam having a smaller lift amount. That is, the function of the lift amount changing mechanism 30 is such that the large cam 32
c, the functioning cam is changed from the large cam 32c to the medium cam 32b, and the cam currently functioning is the medium cam 3
If it is 2b, the function cam is changed from the middle cam 32b to the small cam 32a. Thus, the required load change rate dL
When / dt is a moderate negative value, the intake air amount needs to be reduced relatively largely in order to follow the decrease in the required load L and reduce the output torque. According to the fourth control D, the target lift amount is relatively greatly reduced, and the intake air amount is also relatively greatly reduced. Therefore, a torque that follows a change in the required load can be output.

On the other hand, as described above, the required load change rate dL
When / dt is a moderate negative value and the required load L is a negative value, the above-described second control B is executed. However, the phenomenon that occurs in the internal combustion engine at this time is different from the case of the second control B described above. When the required load L is a negative value, it means that it is necessary to apply a so-called engine brake. In the present embodiment, the engine brake can be applied by executing the second control B. That is, when the required load change rate dL / dt is a moderate negative value, the fuel injection amount decreases. Therefore, the second control B
Therefore, even if the intake air amount increases, the output torque does not increase, but rather decreases. Moreover, since the intake air volume is large, the piston 8
Introduces air into the fuel chamber 6, thereby consuming the energy of the internal combustion engine. Thus, the required load change rate dL / dt
Is a medium value and the required load L is a negative value,
That is, if the second control B is executed when it is necessary to apply the engine brake, the output torque does not increase and the energy of the internal combustion engine is consumed, so that the engine speed decreases.
Thus, according to the present embodiment, the engine brake can be applied as required.

As described above, the required load change rate dL / dt
Is a relatively large negative value and the required load L is a positive value, the setting of the target lift amount follows the fifth control E,
According to this control, the target lift amount is reduced to the maximum.
Therefore, the lift amount changing mechanism 30 changes the functioning cam to the small cam 32a regardless of whether the currently functioning cam is the large cam 32c or the middle cam 32b. As described above, when the required load change rate dL / dt is a relatively large negative value and the required load L is a positive value, the intake air amount is increased to follow the decrease in the required load L and reduce the output torque. It needs to be reduced. According to the fifth control E, the target lift amount is greatly reduced, and the intake air amount is also greatly reduced. Therefore, a torque that follows a change in the required load can be output.

As described above, the required load change rate dL / dt
Is a relatively large negative value and the required load L is a negative value, the third control C is executed. However, the phenomenon that occurs in the internal combustion engine at this time is different from the case of the third control C described above. If the required load L is a negative value as described above, it means that it is necessary to apply the engine brake. In this embodiment, by executing the third control C, the engine brake can be greatly applied.
That is, when the required load change rate dL / dt is a relatively large negative value, the fuel injection amount sharply decreases. For this reason, even if the intake air amount is greatly increased by the third control C, the output torque is not increased but rather becomes very small. In addition, since the intake air amount becomes very large, the piston 8 causes air to flow into the combustion chamber 6.
The energy of the internal combustion engine is largely consumed for introduction into the internal combustion engine. As described above, when the required load change rate dL / dt is a relatively large negative value, that is, when the third control C is executed when it is necessary to apply a large amount of engine brake, the output torque does not increase, and Since a large amount of energy is consumed, the engine speed rapidly decreases. Thus, according to the present embodiment, the engine brake can be applied as required.

In this embodiment, the required load change rate dL / d
When t is a relatively large value and the required load L is a negative value, in addition to executing the third control C, the opening degree of the throttle valve 15 is minimized. According to this, the amount of energy of the internal combustion engine consumed by the piston 8 to introduce air into the combustion chamber 6 is greatly increased, so that the engine brake can be greatly applied as required.

When the required load change rate dL / dt is a relatively large negative value and the required load L is a negative value, in addition to executing the third control C, the fuel injection amount is reduced to zero. It may be. According to this, the output torque of the internal combustion engine becomes zero, so that the engine brake can be greatly applied as required. A specific example of the operation control of the internal combustion engine described above is shown in the flowchart of FIG. First, at step 10, it is determined whether or not the absolute value of the required load change rate dL / dt is larger than a predetermined value α. Step 10
If it is determined that the absolute value of the required load change rate dL / dt is larger than the predetermined value α in step 1,
Proceed to 1. On the other hand, when it is determined in step 10 that the absolute value of the required load change rate dL / dt is equal to or smaller than the predetermined value α, the process proceeds to step 14 and the first control A
Is executed.

In step 11, the required load change rate dL / d
It is determined whether or not the absolute value of t is equal to or larger than a predetermined value α and smaller than a predetermined value β. Β is α
Greater value. When it is determined in step 11 that the absolute value of the required load change rate dL / dt is equal to or larger than the predetermined value α and smaller than the predetermined value β, the process proceeds to step 12. On the other hand, in step 11, the absolute value of the required load change rate dL / dt is set to a predetermined value β.
When it is determined that this is the case, the process proceeds to step 17.

In step 12, the required load change rate dL / d
It is determined whether or not t is greater than zero (dL / dt> 0). When it is determined in step 12 that dL / dt> 0, the process proceeds to step 13 where the second control B is executed. On the other hand, in step 12, dL / dt ≦ 0
When it is determined that is, the routine proceeds to step 15, where it is determined whether or not the required load L is larger than zero (L> 0).
When it is determined in step 15 that L> 0, the routine proceeds to step 16, where the fourth control D is executed. On the other hand, when it is determined in step 15 that L ≦ 0, the process proceeds to step 13 where the second control B is executed.

In step 17, the required load change rate dL / d
It is determined whether or not t is greater than zero (dL / dt> 0). When it is determined in step 17 that dL / dt> 0, the process proceeds to step 18 and the third control C is executed. On the other hand, in step 17, dL / dt ≦ 0
When it is determined that is, the routine proceeds to step 19, where it is determined whether or not the required load L is larger than zero (L> 0).
When it is determined in step 19 that L> 0, the routine proceeds to step 20, where the fifth control B is executed. On the other hand, when it is determined in step 19 that L ≦ 0, the process proceeds to step 18 and the third control C is executed.

FIG. 9 shows an example in which the operation of the internal combustion engine is controlled according to this flowchart. In FIG. 9, (A) indicates a required load, (B) indicates a required load change rate, (C) indicates a cam to be operated, and (D) indicates time. Α and β correspond to predetermined values in the flowchart, La represents a required load corresponding to the engine speed dividing the sixth control S and the seventh control M, and Lb represents a seventh load. This is a required load corresponding to the engine speed that separates the control M from the eighth control L. In the following description, the lift timing is omitted.

At time t2, the required load L is rapidly increased. At this time, since the required load change rate dL / dt is a positive value and the absolute value thereof is larger than a predetermined value β, the cam functioned based on the third control C is the large cam 32a. At time t3, the required load change rate dL / dt is zero, and since its absolute value is smaller than the predetermined value α, the cam functioned based on the first control A is the middle cam 32b. Further, at time t4, the required load L is reduced relatively sharply. At this time, the required load change rate dL / dt is a negative value, and its absolute value is larger than the predetermined value α and smaller than the predetermined value β, so that it is made to function based on the fourth control D. The cam is a small cam 32a.

Next, at time t5, the required load change rate dL /
Since dt is zero and its absolute value is smaller than the predetermined value α, the cam functioned based on the first control A is the middle cam 32b. Further, the required load L gradually decreases from the time t6, and the required load change rate dL at this time.
The absolute value of / dt is smaller than a predetermined value α, and the cam functioned based on the first control A is the middle cam 32.
b is maintained. When the required load L becomes smaller than the predetermined threshold value La at the time t6, the cam functioned based on the first control A is the small cam 32a.

Further, the required load L gradually increases from time t9. At this time, the absolute value of the required load change rate dL / dt is smaller than a predetermined value α, and the function is performed based on the first control A. The cam is maintained on the small cam 32a. When the required load L becomes larger than the predetermined threshold value La at time t10, the cam functioned based on the first control A is the middle cam 32b.

Further, at time t12, the required load L sharply decreases. At this time, the required load change rate dL / dt is a negative value, the absolute value of which is larger than the predetermined value β, and the required load L is zero, so that the function is performed based on the third control C. The cam is a large cam 32c. At time t13, the required load change rate dL / dt is zero, and since its absolute value is smaller than the predetermined value α, the cam functioned based on the first control A is the small cam 32b.

Although the internal combustion engine in the above embodiment is a gasoline engine having a stoichiometric air-fuel ratio as a target air-fuel ratio, the present invention can be applied to any internal combustion engine whose intake air amount should be controlled in accordance with the required load change rate. Can be. Therefore, for example, the present invention can be applied to a so-called lean-burn engine or a diesel engine having a very large target air-fuel ratio.

In the above embodiment, only the depression amount of the accelerator pedal is considered as a factor for changing the required load. However, when the internal combustion engine is mounted on a vehicle such as an automobile, electric power for an air conditioner or the like is generated. For this reason, it is necessary to increase the load (torque) output from the internal combustion engine. Therefore, in addition to the amount of depression of the accelerator pedal, the required power and the like may be considered as a factor for changing the required load.

Further, for example, an internal combustion engine of a type in which a negative pressure formed in an intake passage when air is introduced into a fuel chamber is temporarily accumulated, and a brake is driven using the accumulated negative pressure. There are advantages to applying the present invention.
That is, if the third control is executed when the negative pressure accumulated in the internal combustion engine of this type is insufficient, a large negative pressure can be formed in the intake passage. Therefore, the required negative pressure can be stored at an early stage.

Next, an intake valve driving device according to a second embodiment will be described. The second embodiment is the same as the first embodiment in the configuration of the intake valve driving device, but differs from the first embodiment in the control of the intake valve driving device. According to the basic control of the intake valve driving device in the second embodiment, the target lift amount is set by the controls S, M, and L selected based on the engine speed Ne and the required load L according to the relationship shown in FIG. , Each control S,
A target lift timing is set based on the engine speed Ne and the required load L from a map as shown in FIG. 7 corresponding to M and L, and the set target lift amount and target lift timing are achieved. The lift amount changing mechanism 30 and the lift timing changing mechanism 31 are driven as required.

As described above, an object of the present invention is to reliably and promptly output a torque corresponding to a required load after a change in the required load. It is extremely important to achieve this goal especially when accelerating the engine. In order to achieve the object at the time of engine acceleration, it is necessary to rapidly increase the intake air amount to the target intake air amount and increase the fuel injection amount to the target fuel injection amount. Here, since the operating speed of the fuel injection valve 16 is relatively high, the fuel injection amount can be rapidly increased to its target value.

However, when it is attempted to increase the intake air amount to the target intake air amount by driving the lift amount changing mechanism or the lift timing changing mechanism, the operating speed of these changing mechanisms depends on the state of the factor that determines the operating speed. In some cases, the intake air amount cannot be rapidly increased to the target intake air amount because the air intake amount may be relatively slow in some cases. That is, when the intake air amount is increased by the lift amount changing mechanism 30 or the lift timing changing mechanism 31, depending on the state of the factor that determines the operation speed of these changing mechanisms, the control delay of the intake air amount is caused by the operation delay of these changing mechanisms. Is a problem to be solved.

Therefore, in the second embodiment, when the intake air amount is increased to solve this problem, the intake air amount can be immediately increased to the target intake air amount. According to the additional control executed in addition to the basic control of the second embodiment to achieve this object, at least one of the operating speed of the lift amount changing mechanism 30 and the operating speed of the lift timing changing mechanism 31 is measured in advance. Then, a lower limit value Gamin relating to the intake air amount corresponding to the operating speed V measured based on the relationship shown in FIG. 10 is calculated, and the actual intake air amount is set to be equal to or more than the calculated lower limit value Gamin in all engine operation regions. Try to keep. That is, even if the intake air amount is reduced, the intake air amount is limited so as not to be lower than the lower limit value Gamin. Specifically, the change of the cam to be operated in the lift amount changing mechanism 30 is limited so that the intake air amount does not become smaller than the lower limit Gamin, or the change of the lift timing in the lift timing changing mechanism 31 is limited. In this case, when the lift amount changing mechanism is configured to change the lift amount stepwise as described above, the lift amount is set so that the intake air amount does not become smaller than the lower limit value. When the operation of the change mechanism is limited, and the lift amount change mechanism can continuously change the lift amount, the lift amount by the lift amount change mechanism is set to a certain value so that the intake air amount does not become smaller than the lower limit value. Limit to lift.

Here, as shown in FIG.
When the operation speed V is within a certain range W, the in becomes larger as the operation speed V becomes slower, and when the operation speed V becomes slower than the certain range W, it becomes a certain large constant value. If it is earlier than this, it will have a certain small constant value. Therefore, according to the second embodiment, even if the operating speed V is relatively slow, the intake air amount is maintained at least at the relatively large lower limit value Gamin, so that the amount to be increased when the intake air amount is increased can be reduced. Therefore, the actual intake air amount can be quickly increased to the target intake air amount.

The calculation of the lower limit in the additional control of the second embodiment is shown in the flowchart of FIG. In FIG. 11, first, at step 100, it is determined whether or not the engine is being decelerated. When it is determined in step 100 that the engine is being decelerated, at step 101, at least one of the operating speed V of the lift amount changing mechanism 30 and the operating speed V of the lift timing changing mechanism 31 is measured. The operating speed of the lift amount changing mechanism 30 is measured, for example, from the time required to change a currently functioning cam to another cam. The operating speed of the lift timing changing mechanism 31 is measured, for example, from the time required to drive the lift timing changing mechanism 31 to a phase different from the current phase and to change the current phase to a phase different from the current phase.
Here, when Step 101 is executed, Step 10
Since the engine deceleration operation is determined by 0, even if the phase of the cam functioning in the lift amount changing mechanism 30 or the phase of the lift timing changing mechanism 31 is changed regardless of the required torque or the like, the influence on the engine operation is extremely small. .
Next, at step 102, the lower limit value Gamin regarding the intake air amount corresponding to the operating speed V based on the relationship of FIG.
Is calculated.

On the other hand, when it is determined in step 100 that the engine is not being decelerated, it is determined that driving the lift amount changing mechanism 30 or the lift timing changing mechanism 31 to measure the operating speed V affects the engine operation. Then, the processing routine ends without executing steps 101 and 102. In the second embodiment, the operating speed of the lift amount changing mechanism or the lift timing changing mechanism is directly measured, and the lower limit value regarding the intake air amount is calculated based on the measured operating speed. Since it depends on the temperature or pressure of the oil (engine oil in this embodiment) for driving the change mechanism, the operating speed is estimated based on the temperature or pressure of this oil,
The lower limit may be calculated based on the estimated operating speed, or the lower limit may be calculated directly based on the temperature or pressure of the oil. In this case, the operating speed increases as the oil temperature increases, and the operating speed increases as the oil pressure increases.

When the lower limit value is calculated using the oil temperature or oil pressure as described above, it is not necessary to drive the lift amount changing mechanism or the lift timing changing mechanism in order to measure the operating speed. Step 100 of the flowchart can be omitted. In this case, for example, the lower limit value may be calculated at a predetermined time interval. According to the present invention, the operating speed described above,
The lower limit can also be calculated using factors other than oil temperature or oil pressure, and therefore, according to the present invention, the lower limit is generally a lift change mechanism for a command issued to change the operating speed. Alternatively, it may be calculated based on a factor relating to the responsiveness of the lift timing changing mechanism. The fact that the operation of the internal combustion engine is started may be used as a factor for determining the operation speed of the lift amount changing mechanism or the lift timing changing mechanism. That is, when the operation of the engine is stopped, the pressure of the oil for driving the lift amount changing mechanism and the lift timing changing mechanism is reduced to zero. Therefore, at the next engine start, the lift amount changing mechanism is in a state of driving the intake valve by the small cam, and the lift timing changing mechanism is in the state most retarded. Here, when the engine is started, the combustion of the fuel in the combustion chamber is not stable, so that even if the engine speed is small and the required load is small, the intake air amount needs to be larger than the intake air amount set by the normal intake air amount control. .
However, when the engine is started, the operating speed of these change mechanisms is low because the temperature of the oil for driving the lift amount change mechanism and the lift timing change mechanism is low. Therefore, even if the lift amount changing mechanism or the lift timing changing mechanism is driven in accordance with the normal intake amount control, the intake amount required at the time of starting the engine cannot be secured. Therefore, at the time of engine start, as in the second embodiment, the lower limit of the intake air amount is set to an amount larger than the intake air amount set based on the engine speed and the required load by the normal intake air amount control, and the lift amount changing mechanism is used. And a lift timing changing mechanism is driven. As a specific example, for example, when the engine is started, the target lift amount is set to be larger than the lift amount set by normal intake air amount control. In the illustrated lift amount changing mechanism, the cam set by the normal intake air amount control is changed by one step to a cam having a larger lift amount. According to this, the required intake air amount can be immediately secured even at the time of engine start, thereby improving the engine startability. Further, even when the internal combustion engine is requested to perform an acceleration operation immediately after the start of the engine, a required intake air amount can be secured.

Next, an intake valve driving device according to a third embodiment will be described. The third embodiment is the same as the first embodiment in the configuration of the intake valve driving device, and the same as the second embodiment in the basic control of the intake valve driving device. By the way, when the operation of the internal combustion engine is stopped, the hydraulic chamber 37 of the lift amount changing mechanism 30 is changed.
b, 37c, the pressure of the engine oil supplied to the engine is reduced and the advance timing compartment 4 of the lift timing changing mechanism 31 is moved.
The pressure of the engine oil supplied to 6a and the retarding compartment 46b decreases. As is apparent from the structures of the lift amount changing mechanism 30 and the lift timing changing mechanism 31, the lift amount changing mechanism 30 opens the intake valve 3 by the small cam 32a, and the lift timing changing mechanism 31 is most retarded. State. Therefore, when the operation of the internal combustion engine is started later, the lift amount changing mechanism 30 is operated from the state in which the intake valve 3 is opened by the small cam 32a, and the lift timing changing mechanism 31 is operated from the most retarded state. I'm sullen. At this time, if the target lift amount is the lift amount achieved by the small cam 32a or if the target lift timing is the most retarded timing, there is no problem. For example, changing the 30 cams from the small cam 32a to the middle cam 32b,
In many cases, it is necessary to drive the lift timing changing mechanism 31 to the advance side.

However, when the engine is started, the engine oil temperature is also low, so that the lift amount changing mechanism 3
0 and the operation speed of the lift timing changing mechanism 31 are relatively slow. For this reason, it takes time to set the intake air amount to the target intake air amount, so that it is not possible to immediately output a torque corresponding to the required load. Thus, according to the additional control of the third embodiment, which is executed in addition to the basic control, when the stop of the engine operation is requested or immediately after the engine operation is stopped, the lift amount changing mechanism 30 substantially functions. The medium cam 32b or the large cam 32c,
Alternatively, the lift timing changing mechanism 31 is fixed at a state advanced from a state most retarded by a predetermined amount (hereinafter, a predetermined state). According to this, the next time the operation of the internal combustion engine is started, the cam that functions substantially in the lift amount changing mechanism 30 is the middle cam 32b or the large cam 32c, or the lift timing changing mechanism 31 is Since the advance is made from the retarded state, the intake air amount is immediately set as the target intake air amount, and thus the torque corresponding to the required load can be output immediately.

The additional control of the third embodiment is shown in the flowchart of FIG. In FIG. 12, step 200 is first performed.
It is determined whether or not the stop of the operation of the internal combustion engine has been requested in. When it is determined in step 200 that the stop of the operation of the internal combustion engine has been requested, the process proceeds to step 201, where the cam that functions substantially in the lift amount changing mechanism 30 is set to the middle cam 32b or the large cam 32c, or the lift timing is changed. The operating state of the mechanism 31 is fixed to a state advanced from a state most retarded by a predetermined amount (predetermined state). Here, the lift amount changing mechanism 30
There are various means for fixing the operation state of the lifter to a predetermined state. For example, there is a pin that can protrude from the outside of the hydraulic chambers 37b and 37c of the lift amount changing mechanism 30 to the inside thereof. There are various means for fixing the operation state of the lift timing changing mechanism 31 to a predetermined state. However, for example, from the outside of the advance angle chamber 46a of the lift timing changing mechanism 31 to the inside thereof. There are protruding pins. If the pins are projected into the hydraulic chambers 37b, 37c or the advance compartment 46a when the stop of the internal combustion engine is requested, the lift amount changing mechanism 3
0 or the operation state of the lift timing changing mechanism 31 can be fixed to a predetermined state.

The predetermined state to be fixed when the stop of the operation of the internal combustion engine is requested may be always a constant state or may be variable according to various conditions. For example, before the engine is stopped, a lower limit value of the intake air amount is calculated based on a factor (for example, an operating speed) relating to the responsiveness of the lift amount changing mechanism or the lift timing changing mechanism. The state may be a predetermined state.

Next, an intake valve driving device according to a fourth embodiment will be described. The fourth embodiment is the same as the first embodiment in the configuration of the intake valve driving device, and the same as the second embodiment in the basic control of the intake valve driving device. When the lift amount changing mechanism 30 or the lift timing changing mechanism 31 is driven to increase or decrease the intake air amount during engine acceleration or engine deceleration, these changing mechanisms 30 and 3
Since the operation speed of No. 1 is slow, the intake air amount cannot be quickly changed to the target intake air amount. That is, these change mechanisms 3
A control delay of the intake air amount occurs due to the operation delay of 0,31.

Therefore, according to the additional control of the fourth embodiment, FIG.
A correction coefficient K is calculated based on the required load change rate dL / dt according to the relationship shown in FIG. 3, and the correction coefficient K is set to a target engine oil flow rate (a cam functioning in the lift amount changing mechanism 30 when the required load changes). The amount of engine oil to be introduced into the hydraulic chambers 37b and 37c to change, or the engine oil to be introduced into the advance compartment 46a or the retard compartment 46b in order to make the lift timing the target lift timing. Of the lift amount changing mechanism 30 or the lift timing changing mechanism 31 based on the target engine oil flow rate thus calculated.
Is driven. That is, when the required load change rate dL / dt is larger than a predetermined value, the intake valve opening device;
That is, the control amount for driving and controlling the lift amount changing mechanism 30 or the lift timing changing mechanism 31 is increased.

In the additional control, the correction coefficient K is set as shown in FIG.
Is 1.0 when the required load change rate dL / dt is within a certain range W including zero, and gradually increases as the required load change rate dL / dt increases beyond the range W; When the required load change rate dL / dt becomes a certain value or more, the maximum value becomes a constant value. The correction coefficient K gradually increases as the required load change rate dL / dt falls below the range W and becomes smaller. When the required load change rate dL / dt becomes a certain value or less, the correction coefficient K becomes the largest value and becomes a constant value.

Therefore, according to the additional control of the fourth embodiment, the required load change rate dL / d during engine acceleration and engine deceleration
When t exceeds the range W, the target engine oil flow rate is increased according to the required load change rate dL / dt. For this reason, the cam that substantially functions is immediately changed to the target cam by the lift amount changing mechanism 30, or the lift timing is immediately set to the target lift timing by the lift timing changing mechanism 31, so that the intake air amount is immediately set to the target lift timing. It becomes the intake volume. Thus, according to the fourth embodiment, the torque corresponding to the required load can be output quickly and reliably.

FIG. 1 shows an example of the engine operation in the fourth embodiment.
The results are shown in FIG. In FIG. 14, (A) shows the required load change rate,
(B) shows the actual engine oil flow rate, (C) shows the actual intake air amount, (D) shows the actually output torque, and (E) shows the time. According to FIG. 14, the required load change rate dL / dt at time t0 exceeds the range W in FIG. At this time, the engine oil flow rate Vo is increased as shown by the solid line in FIG. The engine oil flow rate Vo here is not multiplied by the correction coefficient K.
It is larger than the engine oil flow indicated by the chain line in (B).

According to this, as shown by the solid line in FIG. 14 (C), the intake air amount Ga is increased faster than the intake air amount when the correction coefficient is not multiplied (the chain line in FIG. 14 (C)). Therefore, as shown by the solid line in FIG. 14D, the output torque T is increased faster than the torque when the correction coefficient is not multiplied (the chain line in FIG. 14D). For example, the lift amount can be continuously changed by a lift amount changing mechanism, and at the time of engine acceleration, the operating speed of the lift amount changing mechanism can be increased by increasing the target lift amount. The fourth embodiment can also be applied to a case where the intake valve driving device is configured so that the operating speed of the lift amount changing mechanism can be increased by reducing the target lift amount during deceleration. . In this case, for example, as the required load change rate increases, the target lift amount is temporarily increased or decreased at a larger rate according to the required load change rate, and when the initial target lift amount is achieved, or when the intake air amount is increased. When the target intake air amount has been reached, the target lift amount may be used as the initial target lift amount. Alternatively, when the required load change rate is larger than a predetermined value, the target lift amount is temporarily increased or decreased, and when the initial target lift amount is achieved, or when the intake air amount becomes the target intake air amount. Alternatively, the target lift amount may be used as the initial target lift amount. Therefore, in a broad sense, when the target valve opening characteristic is set with respect to the opening characteristic of the intake valve such as the lift amount, and the intake valve driving device is driven to achieve the target valve opening characteristic, the larger the required load change rate is, In a large percentage,
Alternatively, the target valve opening characteristic is temporarily corrected so that the intake air amount is increased or decreased when the required load change rate is larger than a predetermined value, and the initial target valve opening characteristic is achieved. If the target valve opening characteristic is returned to the original target valve opening characteristic, the object of the present invention can be achieved.

If the additional control of the second to fourth embodiments is applied to the first embodiment, the object of the present invention can be achieved more reliably. Furthermore, the object of the present invention can be achieved more reliably even if the additional control of the second to fourth embodiments is combined and applied to the basic control.

The solution of the first embodiment to the fourth embodiment is also applicable to an internal combustion engine in which the amount of air sucked into the combustion chamber can be changed by changing the opening characteristics of the exhaust valve. The present invention can also be used to eliminate a control delay of the exhaust gas amount (or the intake air amount) caused by an operation delay of a mechanism for changing a valve opening characteristic of a valve. The first to fourth embodiments relate to an intake valve driving device driven by engine oil. The present invention is applied to an intake valve driving device driven by electromagnetic force of an electromagnetic solenoid, and The present invention can also be used to eliminate a delay in controlling the amount of intake air due to an operation delay in the driving device.

[0076]

According to the first aspect of the present invention, the degree of opening of the valve is controlled based on the required load change rate. Therefore, even if the target valve opening degree is not changed, when the change rate of the required load is large, the amount of fluid passing through the opening leading to the combustion chamber is reliably and quickly controlled to the target amount. Therefore, according to the present invention, the internal combustion engine can output the torque corresponding to the required load reliably and quickly.

According to the fourth and fifth aspects of the present invention, even if the intake air amount is reduced by changing the valve opening characteristic of the valve, the intake air amount is a factor relating to the responsiveness of the valve opening characteristic changing mechanism or the operating speed. Is maintained more than the lower limit determined in accordance with. Therefore, when the intake air amount is to be increased, the intake air amount is not less than the lower limit at a minimum, so that the intake air amount can be quickly increased to the target intake air amount. Therefore, a torque corresponding to the required load can be output reliably and quickly. According to the eighth aspect, at the time of starting the operation of the engine, a larger amount of air than the amount determined according to the required output is sucked into the combustion chamber. Therefore, combustion in the combustion chamber at the time of starting operation of the engine is stabilized.
That is, a torque corresponding to the engine load necessary for stabilizing the combustion in the combustion chamber at the time of starting the operation of the engine can be output reliably and quickly. According to the ninth aspect, the flow rate of the fluid passing through the opening communicating with the combustion chamber is increased when the change rate of the required load is larger than a predetermined value, and thus the target flow rate is reliably and quickly controlled.
Therefore, according to the present invention, the internal combustion engine can output the torque corresponding to the required load reliably and quickly. According to the tenth aspect, when the required load is larger than the predetermined value, the target valve opening degree is increased, and therefore, the flow rate of the fluid passing through the opening communicating with the combustion chamber is increased, and the target flow rate is reliably and rapidly increased. Is controlled. Therefore, according to the present invention, the internal combustion engine can output the torque corresponding to the required load reliably and quickly.

According to the tenth aspect, the control amount for driving the valve opening characteristic changing mechanism is increased when the required output change rate is greater than a predetermined value. For this reason, the operation speed of the valve opening characteristic changing mechanism is increased, and the intake air amount can be rapidly increased to the target intake air amount. Therefore, the torque corresponding to the required load can be output reliably and quickly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an internal combustion engine provided with an intake valve driving device of the present invention.

FIG. 2 is a diagram showing a configuration of an intake valve driving device of the present invention.

FIG. 3 is a diagram showing a configuration of a lift amount changing mechanism of the present invention.

FIG. 4 is a diagram showing a configuration of a lift timing changing mechanism of the present invention.

FIG. 5 is a diagram showing a relationship between a time Δt, a required load change amount ΔL, and an operation control mode of the internal combustion engine.

FIG. 6 is a diagram showing a relationship among an engine speed Ne, a required load L, and a cam mode.

FIG. 7 is a diagram showing a relationship among an engine speed Ne, a required load L, and a lift timing.

FIG. 8 is a flowchart for controlling the operation of the internal combustion engine.

FIG. 9 is a time chart showing a specific example of operation control of the internal combustion engine.

FIG. 10 is a diagram illustrating a relationship between an operation speed and a lower limit value.

FIG. 11 is a flowchart for executing additional control of the second embodiment.

FIG. 12 is a flowchart for executing additional control of the third embodiment.

FIG. 13 is a diagram showing a relationship between a required load change rate and a correction coefficient.

FIG. 14 is a diagram for explaining a fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine main body 3 ... Intake valve 6 ... Fuel chamber 30 ... Lift amount change mechanism 32a ... Small cam 32b ... Middle cam 32c ... Large cam

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02D 41/04 310 F02D 41/04 310C 320 320 41/10 320 41/10 320 41/12 320 41/12 320 43 / 00 301 43/00 301K 301Z 45/00 312 45/00 312H 312F 312G 312E (72) Inventor Kazuhisa Mogi 1 Toyota Town, Toyota City, Aichi Prefecture F-term in Toyota Motor Corporation (reference) 3G018 AB04 BA01 BA15 BA33 CB03 DA01 DA14 DA72 DA73 DA74 DA83 EA02 EA11 EA16 EA17 EA35 FA04 FA07 GA03 3G084 BA05 BA23 CA04 CA06 CA07 DA04 EB09 FA00 FA07 FA10 FA18 FA20 FA33 FA38 FA39 3G092 AA01 AA11 BA01 DA01 DA02 DA03 DC01 DF04 GA05 GA01 GA03 HE03Z HE04Z HE08Z HF08Z 3G301 HA01 HA19 JA03 KA06 KA12 KA16 KA28 LA01 LA07 NC04 PA01Z PA17Z PE00Z PE01Z PE03Z PE04Z PE08Z PE10Z PF03Z

Claims (12)

[Claims] 1. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, a valve opening degree changing mechanism for changing the valve opening degree of the valve, and a valve for an intake valve according to a required output of the internal combustion engine. Valve opening degree setting means for setting a target valve opening degree, a valve opening timing changing mechanism for changing the valve opening timing of the valve, and setting a target valve opening timing of the valve according to a required output of the internal combustion engine And a valve drive device for an internal combustion engine, comprising: a valve opening timing setting means for setting the required valve opening degree when the required load change rate is larger than a predetermined change rate but the target valve opening degree is not changed. A valve drive device for an internal combustion engine, characterized in that: 2. A throttle valve for shutting off an intake passage of an internal combustion engine, wherein a change rate of a required load of the internal combustion engine is larger than a predetermined change rate and is a negative value, but a target valve opening degree is changed. 2. The valve drive device for an internal combustion engine according to claim 1, wherein the target valve opening degree is increased and the throttle valve is closed when the change is not made. 3. The valve driving device for an internal combustion engine according to claim 1, wherein the target valve opening timing is set according to the target valve opening degree and a required output of the internal combustion engine. 4. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, a valve opening characteristic changing mechanism for changing valve opening characteristics of the valve, and a target valve opening according to a required output of the internal combustion engine. A valve opening characteristic setting means for setting a characteristic, wherein the valve opening device is configured to drive the valve opening characteristic changing mechanism so that the valve opening characteristic becomes the target valve opening characteristic. Setting a lower limit value for the amount of air to be sucked in based on a responsiveness factor of the valve opening characteristic changing mechanism,
A valve driving device for an internal combustion engine, wherein an amount of air sucked into a combustion chamber during operation of the engine is maintained at or above the lower limit. 5. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, a valve opening characteristic changing mechanism for changing valve opening characteristics of the valve, and a target valve opening according to a required output of the internal combustion engine. A valve driving device for an internal combustion engine, comprising a valve opening characteristic setting means for setting characteristics, and driving a valve opening characteristic changing mechanism so that the valve opening characteristic becomes the target valve opening characteristic. A lower limit value for the amount of air to be taken in is set based on the operating speed of the valve opening characteristic changing mechanism, and the amount of air taken into the combustion chamber during operation of the engine is maintained at or above the lower limit value. A valve drive device for an internal combustion engine, characterized by the following. 6. The valve driving device for an internal combustion engine according to claim 5, wherein the lower limit is set to be larger as the operation speed of the valve opening characteristic changing mechanism is lower. 7. The valve drive device for an internal combustion engine according to claim 5, wherein an operation speed of the valve opening characteristic changing mechanism is measured when the engine is decelerated. 8. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, a valve opening characteristic changing mechanism for changing valve opening characteristics of the valve, and a target valve opening according to a required output of the internal combustion engine. A valve drive device for an internal combustion engine, the valve drive device having a valve opening characteristic setting means for setting a characteristic and driving the valve opening characteristic changing mechanism so that the valve opening characteristic becomes the target valve opening characteristic. A valve driving device for an internal combustion engine, wherein a target valve opening characteristic set by the valve opening characteristic setting means is changed such that an amount of air taken into the combustion chamber at a time increases. 9. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, and valve opening characteristic setting means for changing the valve opening characteristic of the valve, wherein the valve opening characteristic is a target valve opening characteristic. In the valve driving device for an internal combustion engine, which drives the valve opening characteristic changing mechanism such that the flow rate of the fluid passing through the opening increases when the change rate of the required output is larger than a predetermined value. Wherein the target valve opening characteristic set by the valve opening characteristic setting means is corrected. 10. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, valve opening degree changing means for changing the valve opening degree of the valve, and a target of the valve according to a required output of the internal combustion engine. In a valve drive device for an internal combustion engine, comprising a target valve opening degree setting means for setting a valve opening degree, a target set by the valve opening degree changing means when a change rate of a required load is larger than a predetermined value. A valve driving device for an internal combustion engine configured to increase a valve opening degree. 11. A valve for opening and closing an opening communicating with a combustion chamber of an internal combustion engine, a valve opening characteristic changing mechanism for changing valve opening characteristics of the valve, and a target valve opening according to a required output of the internal combustion engine. A valve driving device for an internal combustion engine, comprising a valve opening characteristic setting means for setting characteristics, and driving the valve opening characteristic changing mechanism so that the valve opening characteristics become the target valve opening characteristics. A valve driving device for an internal combustion engine, wherein a control amount for driving a valve opening characteristic changing mechanism is increased when a change rate is larger than a predetermined value. 12. The valve opening characteristic changing mechanism includes a valve opening degree changing mechanism for changing a valve opening degree, and a valve opening timing changing mechanism for changing a valve opening timing. 12. The valve drive device for an internal combustion engine according to claim 11.