JP2007120410A - Intake control device for vehicular engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve operation property of a vehicle by avoiding change of intake air quantity with excess response in a device controlling intake air quantity of an engine by continuously changing intake valve opening characteristics. <P>SOLUTION: When acceleration demand of a driver is detected based on change quantity ΔAPS of accelerator opening APS, target opening characteristics of an intake valve is dulled with a dulling coefficient according to the change quantity ΔAPA. In the dulling process, response of the target opening characteristics is delayed more as the driver demands slower acceleration. Consequently, acceleration shock due to too sensitive response of engine torque to slight acceleration operation can be prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake control device for a vehicle engine that controls an intake air amount of an engine by continuously changing an opening characteristic of the intake valve.

In Patent Document 1, the intake valve is opened and closed by a three-dimensional cam in which at least the lift amount of the cam profile is changed in the axial direction, and the lift amount of the intake valve is changed in conjunction with the depression amount of the accelerator pedal. An intake air amount control device that controls the amount of intake air into the cylinder of an engine is disclosed.
JP 2001-182563 A

By the way, when the intake air amount is controlled by the throttle valve, the intake air is distributed to each cylinder after the intake air is charged into the intake collector downstream of the throttle valve. There is a tendency for the change in the intake air amount to be delayed.
On the other hand, in the case of the device that controls the intake air amount by changing the opening characteristic of the intake valve as described above, in order to control the intake air amount immediately before the cylinder, the cylinder is controlled against the control of the opening characteristic of the intake valve. The amount of intake air changes without delay.

  Therefore, in the device that controls the intake air amount by the opening characteristic of the intake valve, the engine output changes with a very fast response to the accelerator operation, but in this case, it is sensitive to a slight accelerator operation. Although engine torque will react and the driver intends to accelerate slowly, the engine output will increase in a short time, and the driver may be given an acceleration shock.

  The present invention has been made in view of the above problems, and in an apparatus for controlling the intake air amount of an engine by continuously changing the opening characteristics of the intake valve, avoids a change in the intake air amount due to an excessive response. An object is to improve the drivability of the vehicle.

Therefore, the vehicle engine intake control apparatus according to the first aspect of the present invention is characterized in that the control speed of the intake valve opening characteristic is changed in accordance with the driver's request for acceleration.
According to such a configuration, since the response when changing the opening characteristic of the intake valve is changed according to the degree of acceleration demand of the driver, it is possible to set a transient response of the intake air amount that meets the driver's request.

Accordingly, it is possible to prevent the engine output from changing suddenly and giving an acceleration shock to the driver in response to the driver's slow acceleration request, and the drivability of the vehicle is improved.
The invention according to claim 2 is characterized in that, in the invention according to claim 1, when the acceleration request of the driver is weak, the control speed of the opening characteristic of the intake valve is made slower than when the acceleration request is strong. .

According to such a configuration, when the acceleration request is weak, the control speed of the opening characteristic of the intake valve is relatively slow so that a change in the engine output corresponding to the driver's slow acceleration request occurs. When it is strong, the control speed of the opening characteristic of the intake valve is made relatively fast so that a high response can be obtained by controlling the intake air amount immediately before the cylinder.
Therefore, it is possible to prevent the engine output from suddenly increasing due to a slow acceleration request and giving an acceleration shock to the driver, while increasing the engine output in a responsive manner at the time of a rapid acceleration request to exhibit high driving performance. it can.

On the other hand, the vehicle engine intake control device according to the invention of claim 3 responds to the acceleration request after temporarily changing the opening characteristic of the intake valve in the reverse direction with respect to the driver's acceleration request. It is characterized by changing the opening characteristics of the intake valve in the direction.
According to this configuration, when a driver's acceleration request is generated, before the intake air amount is increased, the intake valve open characteristic is changed in a direction to temporarily reduce the intake air amount, and then the acceleration request is met. The opening characteristic of the intake valve is changed in a direction to increase the intake air amount.

  Therefore, the response of the increase change of the engine output to the acceleration request is delayed, and the occurrence of the acceleration shock can be avoided.

Embodiments of the present invention will be described below.
FIG. 1 is a system configuration diagram of a vehicle engine in the embodiment.
In FIG. 1, an intake pipe 102 of an engine (gasoline internal combustion engine) 101 is provided with an electronic control throttle 104 that opens and closes a throttle valve 103 b by a throttle motor 103 a, and the electronic control throttle 104 and the intake valve 105 are interposed therebetween. Then, air is sucked into the combustion chamber 106.

Further, an electromagnetic fuel injection valve 131 is provided in the intake port 130 upstream of the intake valve 105 of each cylinder, and the fuel injection valve 131 is an injection pulse of an injection pulse signal sent from an engine control unit 114 described later. An amount of fuel (gasoline) proportional to the width (valve opening time) is injected.
The air-fuel mixture formed in the combustion chamber 106 is ignited and burned by spark ignition by a spark plug (not shown).

The combustion exhaust in the combustion chamber 106 is discharged through the exhaust valve 107, purified by the front catalyst 108 and the rear catalyst 109, and then released into the atmosphere.
The exhaust valve 107 is driven to open and close by a cam 111 provided on the exhaust camshaft 110 while maintaining a constant valve lift, valve operating angle, and valve timing.
On the other hand, on the intake valve 105 side, a variable valve event and lift (VEL) mechanism 112 that continuously varies the valve lift amount of the intake valve 105 together with the operating angle is provided.

Further, on the intake valve 105 side, a VTC (Variable Valve Timing Control) mechanism 113 that continuously varies the center phase of the valve operating angle of the intake valve 105 by changing the rotation phase of the intake side drive shaft with respect to the crankshaft. Is provided.
The engine control unit 114 incorporating the microcomputer sets the fuel injection amount, the ignition timing, the target intake air amount, and the target intake negative pressure by arithmetic processing according to a program stored in advance, and fuel injection based on these. Control signals are output to the valve 131, the power transistor for the ignition coil, the electronic control throttle 104, the VEL mechanism 112, and the VTC mechanism 113.

In this embodiment, the electronic control throttle 104 is provided mainly for generating intake negative pressure, and the intake air amount of the engine 101 is changed by changing the opening characteristics of the intake valve 105 by the VEL mechanism 112 and the VTC mechanism 113. Be controlled.
The engine control unit 114 includes an air flow meter 115 for detecting the intake air amount of the engine 101, an accelerator pedal sensor 116 for detecting the depression amount (opening degree) of an accelerator pedal operated by a vehicle driver, and a reference for the crankshaft 120. A crank angle sensor 117 that outputs a crank angle signal for each rotational position, a throttle sensor 118 that detects the opening TVO of the throttle valve 103b, a water temperature sensor 119 that detects the cooling water temperature of the engine 101, and a reference for an intake drive shaft 3 to be described later A detection signal is input from a cam sensor 132 that outputs a cam signal for each rotational position and an intake pressure sensor 134 that detects an intake manifold pressure (intake pressure) downstream of the throttle valve 103b and upstream of the intake valve 105.

FIG. 2 is a perspective view showing the structure of the VEL mechanism 112.
In the engine 101 of the embodiment, a pair of intake valves 105 are provided in each cylinder, and an intake drive shaft 3 that is rotationally driven by the crankshaft 120 rotates along the cylinder row direction above the intake valves 105. Supported as possible.
A swing cam 4 that contacts the valve lifter 105a of the intake valve 105 and opens and closes the intake valve 105 is fitted on the intake drive shaft 3 so as to be relatively rotatable.

Between the intake drive shaft 3 and the swing cam 4, a VEL mechanism 112 for continuously changing the operating angle and valve lift amount of the intake valve 105 is provided.
A VTC mechanism 113 that continuously changes the center phase of the operating angle of the intake valve 105 by changing the rotational phase of the intake drive shaft 3 with respect to the crankshaft 120 is provided at one end of the intake drive shaft 3. It is arranged.

  As shown in FIGS. 2 and 3, the VEL mechanism 112 includes a circular drive cam 11 that is eccentrically fixed to the intake drive shaft 3 and a ring-shaped link that is externally fitted to the drive cam 11 so as to be relatively rotatable. 12, a control shaft 13 extending in the cylinder row direction substantially parallel to the intake drive shaft 3, a circular control cam 14 eccentrically fixed to the control shaft 13, and a relative rotation with the control cam 14 The rocker arm 15 has one end connected to the tip of the ring-shaped link 12 and a rod-shaped link 16 connected to the other end of the rocker arm 15 and the swing cam 4.

The control shaft 13 is rotationally driven by a motor 17 through a gear train 18 within a predetermined control range.
With the above configuration, when the intake drive shaft 3 rotates in conjunction with the crankshaft 120, the ring-shaped link 12 moves substantially in translation through the drive cam 11, and the rocker arm 15 swings around the axis of the control cam 14. Then, the swing cam 4 swings through the rod-shaped link 16 and the intake valve 105 is driven to open and close.

Further, by driving and controlling the motor 17 to change the rotation angle of the control shaft 13, the axial center position of the control cam 14 serving as the rocking center of the rocker arm 15 changes and the posture of the rocking cam 4 changes. .
As a result, the operating angle of the intake valve 105 and the valve lift amount continuously change while the central phase of the operating angle of the intake valve 105 remains substantially constant.

A detection signal from an angle sensor 133 that detects the rotation angle of the control shaft 13 is input to the engine control unit 114, and the control shaft 13 is rotated to a target angle position corresponding to a target lift amount. The motor 17 is feedback controlled based on the detection result of the angle sensor 133.
FIG. 4 shows the structure of the VTC mechanism 113.

  The VTC mechanism 113 is fixed to the cam sprocket 51 (timing sprocket) rotated by the crankshaft 120 via a timing chain and the end of the intake drive shaft 3, and is rotatably accommodated in the cam sprocket 51. A rotary member 53, a hydraulic circuit 54 that rotates the rotary member 53 relative to the cam sprocket 51, and a lock mechanism 60 that selectively locks the relative rotational position of the cam sprocket 51 and the rotary member 53 at a predetermined position. And.

The cam sprocket 51 includes a rotating part (not shown) having a tooth part meshed with a timing chain (or timing belt) on the outer periphery, and a housing that is disposed in front of the rotating part and rotatably accommodates the rotating member 53. 56, and a front cover and a rear cover (not shown) for closing the front and rear openings of the housing 56.
The housing 56 has a cylindrical shape with openings at the front and rear ends, and has a trapezoidal shape in cross section on the inner peripheral surface. It is projecting at.

The rotating member 53 is fixed to the front end of the intake drive shaft 3, and four vanes 78 a, 78 b, 78 c, 78 d are provided on the outer peripheral surface of the annular base 77 at 90 ° intervals.
Each of the first to fourth vanes 78a to 78d has a substantially inverted trapezoidal cross section, and is disposed in a recess between the partition walls 63. The recesses are separated from each other in the rotational direction, and the vanes 78a to 78d. An advance side hydraulic chamber 82 and a retard side hydraulic chamber 83 are formed between both sides and both side surfaces of each partition wall 63.

The lock mechanism 60 is configured such that the lock pin 84 engages with an engagement hole (not shown) at the rotation position (reference operation state) on the maximum retard angle side of the rotation member 53.
The hydraulic circuit 54 includes two systems, a first hydraulic passage 91 that supplies and discharges hydraulic pressure to the advance side hydraulic chamber 82 and a second hydraulic passage 92 that supplies and discharges hydraulic pressure to the retard side hydraulic chamber 83. These hydraulic passages 91 and 92 are connected to a supply passage 93 and drain passages 94a and 94b through passage switching electromagnetic switching valves 95, respectively.

The supply passage 93 is provided with an engine-driven oil pump 97 that pumps the oil in the oil pan 96, while the downstream ends of the drain passages 94 a and 94 b communicate with the oil pan 96.
The first hydraulic passage 91 is connected to four branch passages 91 d that are formed substantially radially in the base 77 of the rotating member 53 and communicate with the advance-side hydraulic chambers 82. It is connected to four oil holes 92 d that open to the retard side hydraulic chamber 83.

The electromagnetic switching valve 95 is configured such that an internal spool valve body relatively switches and controls the hydraulic passages 91 and 92, the supply passage 93, and the drain passages 94a and 94b.
The engine control unit 114 controls the energization amount for the electromagnetic actuator 99 that drives the electromagnetic switching valve 95 based on a duty control signal on which a dither signal is superimposed.

For example, when a control signal (OFF signal) with a duty ratio of 0% is output to the electromagnetic actuator 99, the hydraulic oil pressure-fed from the oil pump 47 is supplied to the retard-side hydraulic chamber 83 through the second hydraulic passage 92. At the same time, the hydraulic oil in the advance side hydraulic chamber 82 is discharged from the first drain passage 94 a into the oil pan 96 through the first hydraulic passage 91.
Therefore, the internal pressure of the retard side hydraulic chamber 83 is high and the internal pressure of the advance side hydraulic chamber 82 is low, and the rotating member 53 rotates to the maximum retard side via the vanes 78a to 78b. The opening period of the intake valve 105 (the center phase of the valve operating angle) is delayed.

On the other hand, when a control signal (ON signal) with a duty ratio of 100% is output to the electromagnetic actuator 99, the hydraulic oil is supplied into the advance side hydraulic chamber 82 through the first hydraulic passage 91 and the retard side hydraulic pressure is supplied. The hydraulic oil in the chamber 83 is discharged to the oil pan 96 through the second hydraulic passage 92 and the second drain passage 94b, and the retard side hydraulic chamber 83 becomes low pressure.
For this reason, the rotating member 53 rotates to the maximum advance side via the vanes 78a to 78d, and thereby the opening period of the intake valve 105 (the center phase of the valve operating angle) is accelerated.

A mechanism for continuously changing the operating angle and lift amount of the intake valve 105 and a mechanism for continuously changing the center phase of the valve operating angle of the intake valve 105 are shown in FIGS. It is not limited to that.
Further, the mechanism for making the opening characteristic of the intake valve 105 variable is not limited to the combination of the VEL mechanism 112 and the VTC mechanism 113, for example, as disclosed in JP-A-2001-182563. A mechanism using a three-dimensional cam or a mechanism for opening and closing an engine valve by an electromagnet as disclosed in Japanese Patent Laid-Open No. 2000-213663 can be employed.

Next, the control of the electronic control throttle 104, the VEL mechanism 112, and the VTC mechanism 113 by the engine control unit 114 will be described in detail according to the flowchart of FIG.
In the flowchart of FIG. 5, first, in step S11, a target intake air amount is calculated from the accelerator opening and the engine speed.

In step S12, a target negative pressure is calculated to respond to a negative pressure request for evaporation purge from the canister, a negative pressure request in the brake master back, and the like. The target negative pressure is a target value when the suction negative pressure is generated by the closing control of the throttle valve 103b.
In step S13, the target throttle opening of the throttle valve 103b is calculated based on the target intake air amount and the target negative pressure.

In step S14, the target intake air amount is corrected and set according to the target negative pressure.
In step S15, based on the target intake air amount corrected and set in step S14, the target lift amount (target angle of the control shaft 13) in the VEL mechanism 112 and the target advance angle of the valve timing in the VTC mechanism 113. Set the value.
In step S16, the electronic control throttle 104 is controlled according to the target throttle opening.

In step S17, the VEL mechanism 112 and the VTC mechanism 113 are controlled according to the target lift amount and the target advance value.
The flowchart of FIG. 6 shows the control of the VEL mechanism 112 and the VTC mechanism 113 in step S17.
In the flowchart of FIG. 6, in step S101, a change amount ΔAPS (opening change rate) per unit time of the accelerator pedal opening APS is calculated.

The change amount ΔAPS is calculated by subtracting the accelerator pedal opening a unit time ago from the latest accelerator pedal opening.
The change amount ΔAPS is data indicating a positive value when the accelerator pedal opening degree is increasing and indicating the degree of acceleration demand of the driver.
In step S102, it is determined whether or not the driver is requested to accelerate by determining whether or not the amount of change ΔAPS is a positive value.

If it is determined that the acceleration is not requested, the process proceeds to step S103, and the VEL mechanism 112 and the VTC mechanism are set with the target lift amount and the target advance value set in step S15 as final target values, respectively. 113 is controlled.
On the other hand, if it is determined in step S102 that the driver requests acceleration, the process proceeds to step S104.

In step S104, the smoothing coefficient KN (0 ≦ KN ≦ 1) used for the smoothing process of the target lift amount and the target advance value set in step S15 is set based on the change amount ΔAPS.
The smoothing coefficient KN is a coefficient that increases the target delay actually used for control with respect to the target lift amount and the target advance value set in step S15 as the value thereof increases. The smaller the ΔAPS is, the larger the value is set.

  That is, when it is determined that the change amount ΔAPS is small and the driver requests slow acceleration (acceleration request is weak), the target lift amount and the target advance value ( If the setting is made so that the change in the opening characteristic of the intake valve 105 is delayed, and conversely, when it is determined that the change amount ΔAPS is large and the driver is requesting rapid acceleration (the acceleration request is strong), the accelerator The target lift amount and the target advance angle value (open characteristics of the intake valve 105) are set to follow and change without delay with respect to the pedal opening change.

In step S105, the target lift amount and the target advance value set in step S15 are smoothed using the smoothing coefficient KN.
Specifically, the target lift amount and the target advance value set in step S15 this time are set as the latest target values, and the target lift amount and the target advance value used in the previous control of the VEL mechanism 112 and the VTC mechanism 113 are set. When this is the previous final target value, this final target value is
Current final target value = last final target value × KN + latest target value × (1−KN)
Calculate as

  However, the present invention is not limited to the configuration in which the smoothing process is performed. For example, the target lift amount and the target advance value are passed through an analog or digital filter, and the data after passing is set as a final target value. The time constant of the filter can be increased as the amount of change ΔAPS is smaller. As a method of setting the final target value delayed with respect to the target lift amount and the target advance value set in step S15. Various known methods can be applied.

In step S106, the VEL mechanism 112 and the VTC mechanism 113 are controlled based on the final target value after the annealing process in step S105.
As in the present embodiment, when the intake air amount of the engine 101 is controlled by the intake valve 105, the intake air amount is adjusted immediately before the cylinder. Therefore, compared to the case where the intake air amount is controlled by the throttle valve 103b, The cylinder intake air amount can be changed with good response.

However, when the driver is requesting slow acceleration, if the cylinder intake air amount changes with good response, the engine output reacts sensitively to the movement of the accelerator, giving an acceleration shock to the driver. there is a possibility.
On the other hand, when the smoothing process is performed on the target value of the opening characteristic of the intake valve 105 as in the above-described embodiment, the target lift amount with respect to the change in the accelerator opening degree is requested at the time of a slow acceleration request for the driver to depress the accelerator pedal slowly. And the response of the target advance value (opening characteristic of the intake valve 105), in other words, the control speed of the opening characteristic of the intake valve 105 is slow (see FIG. 7). Even if the amount is controlled, the engine output does not change responsively and it is possible to prevent the driver from being given an acceleration shock.

On the other hand, when the driver demands rapid acceleration, the target lift amount and the target advance value (open characteristics of the intake valve 105) are changed with a relatively responsive response to changes in the accelerator opening. High acceleration performance can be exhibited by taking advantage of high response performance by controlling the intake air amount with the valve 105.
By the way, in the embodiment shown in the flowchart of FIG. 6, it is determined whether or not to perform the smoothing process based on whether or not the driver is in an acceleration request state, but the smoothing process is most required. Since it is at the time of the driver's request for slow acceleration, the smoothing process can be performed only at the time of request for slow acceleration as in the second embodiment shown in the flowchart of FIG.

In the flowchart of FIG. 8, in step S201, the change amount ΔAPS is calculated in the same manner as in step S101.
In step S202, it is determined whether or not the driver is requesting slow acceleration by determining whether or not the change amount ΔAPS is positive and the absolute value thereof is equal to or less than a predetermined value.
If it is not a slow acceleration request, that is, if a steady, sudden acceleration, or deceleration operation is requested, the process proceeds to step S203, and the target lift amount and the target advance value set in step S15 are finalized. The VEL mechanism 112 and the VTC mechanism 113 are controlled as target values.

On the other hand, if it is determined in step S202 that the driver is requesting slow acceleration, the process proceeds to step S204.
In step S204, even in the same slow acceleration state, the smoothing coefficient KN is set to a larger value as the acceleration request is weaker (the smaller the change amount ΔAPS is).
In step S205, in the same manner as in step S105, the target lift amount and target advance value set in step S15 are subjected to an annealing process according to the smoothing coefficient KN, and the result is obtained. The final target value is set (see FIG. 7).

In the next step S206, the VEL mechanism 112 and the VTC mechanism 113 are controlled by using the target lift amount and the target advance value smoothed in step S205 as final target values, respectively.
In the first and second embodiments shown in the flowcharts of FIGS. 6 and 8, the target lift amount and the target advance value are subjected to the smoothing process, resulting in the control speed of the opening characteristic of the intake valve 105. However, as in the third embodiment shown in the flowchart of FIG. 9, during the slow acceleration, the open characteristic of the intake valve 105 is temporarily reversed (intake air amount decreasing direction). By changing to the direction corresponding to the acceleration request (increase direction of the intake air amount), the rise response of the engine output (intake air amount) can also be delayed, thereby generating an acceleration shock. Can be suppressed.

In the flowchart of FIG. 9, in step S301, the change amount ΔAPS is calculated as in step S101.
In step S302, it is determined whether or not the driver is requesting slow acceleration by determining whether or not the change amount ΔAPS is positive and the absolute value thereof is equal to or less than a predetermined value.
If it is not a slow acceleration request, that is, if a steady, sudden acceleration, or deceleration operation is requested, the process proceeds to step S303, and the target lift amount and the target advance value set in step S15 are finalized. The VEL mechanism 112 and the VTC mechanism 113 are controlled as target values.

On the other hand, if it is determined in step S302 that the driver is requesting slow acceleration, the process proceeds to step S304.
In step S304, it is determined whether or not it is within a predetermined period immediately after the generation of the slow acceleration request.
If it is within a predetermined period immediately after the generation of the slow acceleration request, the process proceeds to step S305, in which the target lift amount and the target advance value set in step S15 are reversed, that is, the intake air amount is decreased. In the next step S306, the VEL mechanism 112 and the VTC mechanism 113 are controlled based on the target lift amount and the target advance value corrected in the reverse direction.

The predetermined period during which the control in the reverse direction is performed and / or the correction width in the reverse direction can be variably set according to the amount of change ΔAPS, but is a fixed value stored in advance. You can also.
On the other hand, if it is in the slow acceleration request state but is not within the predetermined period immediately after the generation of the slow acceleration request, the process proceeds to step S307, and in the same manner as in step S204, the acceleration is further accelerated even in the same slow acceleration state. The smoothing coefficient KN is set to a larger value as the request is weaker (the smaller the change amount ΔAPS is).

In step S308, in the same manner as in step S105, the target lift amount and the target advance value set in step S15 are subjected to an annealing process according to the smoothing coefficient KN. Final target value.
That is, immediately after the acceleration request is generated, after the target opening characteristic of the intake valve 105 is temporarily changed in the decreasing direction of the intake air amount, the control target that changes after the original target opening characteristic by the annealing process is changed. Set (see FIG. 10).

In the next step S309, the VEL mechanism 112 and the VTC mechanism 113 are controlled by using the target lift amount and the target advance value smoothed in step 308 as final target values, respectively.
By the way, in each of the above embodiments, the control speed of the opening characteristic of the intake valve is changed by correcting the target lift amount and the target advance value, but the VEL mechanism is based on the target lift amount and the target advance value. The control speed of the opening characteristic of the intake valve can also be changed by changing the gain for feedback control of the 112 and the VTC mechanism 113.

The flowchart of FIG. 11 shows a fourth embodiment in which the control speed of the opening characteristic of the intake valve 105 with respect to accelerator change is changed by setting the feedback gain.
In the flowchart of FIG. 11, in step S401, the change amount ΔAPS is calculated in the same manner as in step S101.
In step S402, it is determined whether or not the driver is requested to accelerate by determining whether or not the amount of change ΔAPS is a positive value.

If the acceleration is not requested, the process proceeds to step S403, where a basic value is set as a feedback gain. In the next step S404, the target lift amount and the target advance value are set based on the feedback gain as the basic value. Thus, the VEL mechanism 112 and the VTC mechanism 113 are feedback-controlled.
The feedback control is performed by, for example, a proportional / integral operation based on a deviation of an actual value with respect to a target lift amount and a target advance value, and in step S403, as a proportional gain used for the proportional operation and an integral gain in the integral operation, A basic value stored in advance is set.

The feedback control is not limited to that based on proportional / integral operation, and may be based on, for example, proportional / integral / differential operation, or a system that controls the target by sliding mode control. .
On the other hand, if it is determined in step S402 that the driver has requested acceleration, the process proceeds to step S405, and a feedback gain (for example, proportional gain / integral gain) is set according to the change amount ΔAPS.

  Here, for example, when the proportional gain / integral gain is variably set according to the change amount ΔAPS, when it is determined that the change amount ΔAPS is small and the driver is requesting slow acceleration, the proportional gain · The integral gain is set to a small value, and when it is determined that the change amount ΔAPS is large and the driver is requesting rapid acceleration, the proportional gain / integral gain is set to a relatively large value.

In the next step S406, feedback control is performed on the VEL mechanism 112 and the VTC mechanism 113 so that the target lift amount and the target advance value are obtained based on the feedback gain set in step S405.
As described above, if the feedback gain is set to be variable, the actual lift amount with respect to the changes in the target lift amount and the target advance value (open characteristics of the intake valve 105) corresponding to the change in the accelerator pedal opening. The speed at which the advance value changes changes, and when the slow acceleration is requested, the control speed of the opening characteristic of the intake valve 105 is slowed down with respect to the change in the opening degree of the accelerator pedal (see FIG. 12). The control speed of the opening characteristic of the intake valve 105 with respect to the change in the opening is relatively increased.

Therefore, when the driver requests a slow acceleration, the engine output does not change responsively to the change in the accelerator pedal opening, and it is possible to prevent the driver from receiving an acceleration shock, while the driver makes a sudden acceleration. When requested, the engine output can be changed with good response to the change in the accelerator opening, and high acceleration performance can be exhibited.
Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with effects.
(A) In the vehicle engine intake control device according to any one of claims 1 to 3,
An intake control apparatus for a vehicle engine, wherein a driver's acceleration request is determined based on a change amount per unit time of an accelerator opening.

According to such a configuration, if the accelerator opening change operated by the driver is fast, it is determined that the rapid acceleration is requested, and if the accelerator opening change is relatively slow, it is determined that the slow acceleration is requested. .
Therefore, the degree of acceleration demand of the driver can be detected simply and accurately.
(B) In the vehicle engine intake control apparatus according to claim 1 or 2,
An intake control device for a vehicular engine, wherein a control speed of the open characteristic of the intake valve is changed by delaying a transient response of a target value of the open characteristic of the intake valve.

According to this configuration, for example, by delaying the transient response of the target value of the open characteristic set according to the accelerator opening, etc., and controlling the open characteristic of the intake valve based on the target value delayed in the response, the driver The opening characteristic of the intake valve can be changed at a control speed corresponding to the degree of acceleration demand.
(C) In the vehicle engine intake control apparatus according to claim (b),
Smoothing the target value of the opening characteristic of the intake valve with a smoothing coefficient according to the degree of acceleration demand of the driver, and controlling the opening characteristic of the intake valve based on the target value after the smoothing process An intake control device for an engine for a vehicle.

According to such a configuration, for example, the target value of the opening characteristic set according to the accelerator opening degree is smoothed with the smoothing coefficient according to the driver's acceleration request degree, and the target subjected to the smoothing process is processed. By controlling the opening characteristic of the intake valve so as to be a value, the control speed of the opening characteristic of the intake valve can be changed according to the degree of acceleration demand of the driver.
(D) In the vehicle engine intake control apparatus according to claim 1 or 2,
An intake control device for a vehicular engine, wherein a control speed of an open characteristic of the intake valve is changed by changing a gain in feedback control of the open characteristic of the intake valve.

According to this configuration, by changing the gain in feedback control that brings the actual opening characteristic of the intake valve closer to the target opening characteristic, the opening characteristic of the intake valve is changed at a control speed according to the degree of acceleration demand of the driver. be able to.
(E) In the intake control device for a vehicle engine according to any one of claims 1 to 3,
A first variable valve mechanism that continuously changes the lift amount and / or operating angle of the intake valve; and a second variable valve mechanism that continuously changes the center phase of the operating angle of the intake valve. An intake control device for a vehicular engine, wherein an opening characteristic of the intake valve is changed by the first variable valve mechanism and the second variable valve mechanism.

  According to such a configuration, the intake air amount of the engine can be controlled by continuously changing the lift amount and / or operating angle of the intake valve and the center phase of the operating angle.

The system diagram of the engine for vehicles in an embodiment. The perspective view which shows the variable valve mechanism of the intake valve in embodiment. The figure which shows the VEL mechanism in embodiment. The figure which shows the VTC mechanism in embodiment. The flowchart which shows the intake control in embodiment. The flowchart which shows 1st Embodiment of intake valve control. The time chart which shows the mode of the change of the target opening characteristic of the intake valve in the said 1st Embodiment. The flowchart which shows 2nd Embodiment of intake valve control. The flowchart which shows 3rd Embodiment of intake valve control. The time chart which shows the mode of the change of the target opening characteristic of the intake valve in the said 3rd Embodiment. The flowchart which shows 4th Embodiment of intake valve control. The time chart which shows the mode of the change of the actual opening characteristic of the intake valve in the said 4th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Intake drive shaft, 13 ... Control shaft, 99 ... Electromagnetic actuator, 101 ... Engine, 104 ... Electronic control throttle, 105 ... Intake valve, 112 ... VEL mechanism, 113 ... VTC mechanism, 114 ... Engine control unit, 116 ... Accelerator Pedal sensor, 117 ... crank angle sensor, 120 ... crankshaft

Claims (3)

In an intake control device for a vehicle engine that controls the intake air amount of the engine by continuously changing the opening characteristics of the intake valve,
An intake control apparatus for a vehicular engine, wherein a control speed of an opening characteristic of the intake valve is changed according to a driver's acceleration request degree. 2. The intake control apparatus for a vehicle engine according to claim 1, wherein when the driver's acceleration request is weak, the control speed of the opening characteristic of the intake valve is made slower than when the acceleration request is strong. In an intake control device for a vehicle engine that controls the intake air amount of the engine by continuously changing the opening characteristics of the intake valve,
A vehicle characterized by temporarily changing an opening characteristic of the intake valve in a reverse direction in response to a driver's acceleration request, and then changing the opening characteristic of the intake valve in a direction corresponding to the acceleration request. Engine intake control system.