JPH05340275A - Intake contol device of internal combustion engine - Google Patents

Abstract

PURPOSE:To control an engine speed to a target idling speed with high accuracy, and stably at the time of idling. CONSTITUTION:As a throttle valve 14 has a prescribed clearance, intake air is passing the clearance at the time of idling. An intake manifold 13 is branched into intake passages 13a,... which are communicated with respective cylinders 5 to 8, and intake control valves 2 are provided in respective intake passages 13a.... An idling number of revolution is regulated by controlling the intake control valve 2. The delay time of feed back control is unified and shortened since the intake control valve 2 is provided in the vicinity of each cylinder 5 to 8 comparing with an idling speed control valve (ISCV), and at an equal distance to each cylinder 5 to 8. It is possible to control the idling rotational number of an engine with high accuracy and stably since an intake air-fuel mixture amount is regulated per cylinder by the intake control valve 2 provided per intake passage 13a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device for an internal combustion engine, which controls the amount of air-fuel mixture sucked into each cylinder in order to adjust the idle speed of the internal combustion engine during idling.

[0002]

2. Description of the Related Art A conventional internal combustion engine is disclosed in Japanese Patent Laid-Open No. 63-290.
As described in Japanese Patent Publication No. 37, 37, a bypass passage for bypassing the throttle valve to allow the intake air to flow therethrough when the throttle valve is fully closed, and an idle speed control for adjusting the amount of intake air flowing through the bypass passage provided in the bypass passage. An intake control device having a valve (hereinafter abbreviated as ISCV) and further provided with a rotation speed sensor for detecting the engine rotation speed of the internal combustion engine is provided.

In this type of intake control device, the engine speed is detected when the internal combustion engine is idling, and based on this, I
By changing the opening of the SCV and adjusting the intake air amount, the engine speed can be controlled to a predetermined target idle speed.

[0004]

However, the air-fuel mixture is supplied to each cylinder of the internal combustion engine through a plurality of intake passages branched downstream of the throttle valve and the bypass passage. Since each of these intake passages has a predetermined length, the amount of the air-fuel mixture sucked into each cylinder changes after the ISCV opening is changed, and the output torque of each cylinder changes. There was a predetermined delay time until. Therefore, the above delay time exists in the feedback control system of the ISCV opening based on the engine speed. If such a delay time is long, the control accuracy cannot be sufficiently improved even if the correction function is used in the feedback control system.

Moreover, since the length from the branch point of each intake passage to the cylinder is different depending on the cylinder, the delay time is different for each cylinder. Therefore, there is a variation in each cylinder in the time when the change in the ISCV opening is reflected in the output torque of each cylinder. That is, the delay time of the feedback control system differs for each cylinder. Therefore, a correction function for simultaneously correcting the delay time for each cylinder cannot be obtained. Therefore,
This type of intake control device could not stably control to the target idle speed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an intake control device for an internal combustion engine, which can control the engine speed to a target idle speed with high accuracy and stability during idling. It was

[0007]

The present invention, which has been made to achieve the above object, secures a predetermined intake passage when an accelerator operation is not performed, as illustrated in FIG. Means, a plurality of intake control valves that are provided for each of a plurality of intake passages that communicate with each cylinder of the internal combustion engine, and that open and close the intake passages; Rotation speed detecting means for detecting the engine speed of the internal combustion engine, and at the time of idling of the internal combustion engine, the difference between the engine speed of the internal combustion engine detected by the speed detecting means and a predetermined target idle speed An opening / closing control unit that brings the engine speed closer to the target idle speed by controlling the opening / closing drive unit based on the adjustment of the amount of the air-fuel mixture sucked into each cylinder. Internal combustion engine The intake control device has the gist.

[0008]

In the present invention thus constituted, the intake flow passage ensuring means secures a predetermined intake flow passage during idling when the accelerator operation is not performed. The intake air taken in through the intake passage is supplied to each cylinder as an air-fuel mixture through each intake passage. An intake control valve is provided in each cylinder, and the opening / closing drive means adjusts the amount of the air-fuel mixture sucked into each cylinder by opening / closing each intake control valve provided in each intake passage. To do. That is, in the intake stroke of each cylinder, it is possible to adjust the intake air-fuel mixture amount by adjusting the opening / closing timing and the opening degree of the intake control valve.

The opening / closing control means controls the opening / closing drive means on the basis of the difference between the engine speed of the internal combustion engine detected by the engine speed detecting means and a predetermined target idle speed, and the engine speed is controlled. The number is brought close to the above target idle speed. Here, the intake control valve is provided closer to each cylinder than the conventional ISCV, and is also provided for each cylinder. Therefore, the delay time in the feedback control system of each cylinder can be made short and uniform.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention. In FIG. 1, the four-cylinder engine 1 is provided with an intake valve 11 and an exhaust valve 12 for each cylinder 5, 6, 7, and 8. Further, the intake manifold 13 at the upstream position of each intake valve 11 is branched into four intake passages 13a communicating with the respective cylinders 5 to 8, and the intake control valve 2 is provided in each intake passage 13a. Be done.

The intake control valve 2 is, as shown in FIG. 2, a butterfly type circular valve plate 21 disposed in an intake passage 13a.
Have. The valve plate 21 is screwed to the support shaft 22 and is rotated and opened / closed. As shown in FIG. 3, the circular valve plate 21 has a structure which swings in a non-contact manner with a very narrow clearance with respect to the wall of the intake passage 13a. The support shaft 22 is supported on the wall of the intake passage 13a by a bearing, and its end portion extends into the lower drive portion.

The support shaft 2 extending into the casing 23 of the drive unit.
A magnet member 24 is fitted on the outer circumference of the circle 2 and magnetic poles are formed on the magnet member 24 so as to have different poles symmetrically in the circumferential direction. Also, on the inner wall of the casing 23,
As shown in FIG. 4, a pair of electromagnetic coils 25a and 25b facing the magnet member 24 and a pair of permanent magnets 26a and 26.
b and are arranged.

As shown in FIG. 5, the opening of the valve plate 21 is determined by the balance between the coercive force F1 between the permanent magnet 26a and the magnet member 24 and the magnetomotive torque F2 between the electromagnetic coil 25b and the magnet member 24. Therefore, by controlling the current value of the electromagnetic coil 25b, the valve plate 21 is opened 90 ° (fully opened).
It can be opened and closed to any opening from 0 to 0 (fully closed). The same applies to the permanent magnet 26b and the electromagnetic coil 25a. As a result, it is possible to obtain a partially opened degree of opening such as the control valve positions 21a and 21b indicated by the broken line and the two-dot chain line in FIG. Here, the magnet member 24,
Electromagnetic coils 25a and 25b, and permanent magnet 26a
And 26b correspond to the opening / closing drive means.

As shown in FIG. 1, the intake manifold 13
A throttle valve 14 that is operated via an accelerator pedal (not shown) to adjust the amount of air taken into the engine 1 is disposed upstream of the above. The throttle valve 14 has a predetermined clearance even when the accelerator pedal is not operated, and is configured to ensure a predetermined intake flow path required for idling. That is, the throttle valve 14
The clearance of corresponds to the intake passage securing means. The intake control valve 2 is opened / closed by an energization signal from an input / output unit 32 of a control circuit 3 as an opening / closing control unit having a CPU 31 built therein. The control circuit 3 is provided with a ROM 33 for storing a control program and a RAM 34 for storing control data.

The intake control valve 2 is opened and closed by the calculation in the control circuit 3 to which various signals such as the engine speed are input.
This is done by issuing the energization signal at an appropriate time. In the engine 1, a crank angle sensor 35 that outputs a pulse signal when the pistons of the cylinders 5 to 8 are located at the top dead center (TDC), a rotation speed sensor 36 that outputs a pulse signal at every predetermined crank angle, A torque sensor 37 for detecting the torque for each cylinder, an intake pipe pressure sensor 38 for detecting the air amount for each cylinder, a throttle sensor 39 for detecting the amount of depression of the accelerator, that is, the load state of the engine 1, and a water temperature for detecting the water temperature of the cooling water. A detection sensor 40, an emission detection sensor 41 that detects the state of emission, and the like are provided. In the vicinity of the throttle valve 14, an idle switch for detecting the idle position of the throttle valve 14 is provided, and a throttle position sensor 42 for detecting the opening degree of the throttle valve 14 is arranged.

In the present embodiment, the intake control valve 2 is opened / closed based on the signals from the above-mentioned sensors, and the idle speed is controlled by adjusting the amount of air-fuel mixture sucked into each cylinder 5-8. There is. Next, the operation of this embodiment configured as described above will be described. 6 to 9 are time charts showing the control pattern of the intake control valve 2 in the embodiment.

FIG. 6 shows that the opening timing of the intake control valve 2 is fixed,
This shows a pattern for controlling only the valve closing timing. When the valve opening timing is fixed before the intake valve is opened as shown in FIG. 6, it is possible to prevent the pressure in the cylinder from decreasing and reduce the load. FIG. 7 shows a pattern in which the closing timing of the intake control valve 2 is fixed and only the opening timing is controlled. As shown in FIG. 7, when the valve closing timing is fixed near the bottom dead center BDC or after the intake valve is closed, it is possible to prevent the stirring effect (swirl effect) in the cylinder from being attenuated and to obtain good combustibility. You can FIG. 8 shows a pattern for controlling both the opening timing and the closing timing of the intake control valve 2. By performing the control in this way, it is possible to perform control having both the characteristics of the valve opening timing control and the characteristics of the valve closing timing control. FIG. 9 shows a pattern in which the valve closing timing is controlled and the opening degree of the intake control valve 2 is partially opened. When the partial opening control is performed in this way, the opening time of the intake control valve 2 can be lengthened,
This can improve the accuracy of control. Then, these various control patterns are appropriately selected according to the characteristics of the engine 1. Hereinafter, a detailed control method will be described with respect to the pattern of FIG. 6 in which only the closing timing of the intake control valve 2 is controlled during idling. Similar control methods can be considered for the patterns of FIGS. 7 to 9.

FIG. 10 is a flow chart showing the main routine of the opening / closing control processing of the intake control valve 2 in the below-mentioned first to fourth embodiments. Note that this processing is performed by the engine 1
Is a process that is repeatedly executed at predetermined time intervals during the operation.
When the processing is started, first, at step 1001, it is determined based on a signal from the throttle position sensor 42 whether the engine 1 is in the idle state. That is, when the throttle valve 14 is in the idle position, it is determined that the throttle valve 14 is in the idle state. The determination of the idle position may be made based on the signal from the throttle sensor 39. When it is determined that the vehicle is idle, step 100
Move to 3. In step 1003, the target idle speed θ based on the cooling water temperature detected based on the signal from the water temperature detection sensor 40, the electric load, the air conditioner load, and the shift position of the shift lever in the case of a torque converter vehicle.
Calculate 1. In the following step 1005, the closing timing of each intake control valve 2 is corrected by the control valve closing timing correction routine, which will be described later, and the process ends.

On the other hand, if it is determined in step 1001 that the idle state is not established, the process proceeds to step 1007. In step 1007, the accelerator depression amount, that is, the load of the engine 1 is read based on the signal from the throttle sensor 39, and the actual engine speed θ is read based on the signal from the rotational speed sensor 36. In the following step 1009,
The valve opening timing and valve closing timing of the intake control valve 2 are calculated as described below.

That is, first, in calculating the valve opening timing and valve closing timing of the intake control valve 2, the top dead center TD of the valve opening timing is calculated.
The advancing amount with respect to C is the valve opening timing TO, the valve closing timing is at the bottom dead center B
The amount of advance for DC is set as the valve closing timing TC. Opening time T
O is calculated from Table 1 based on the actual engine speed θ of the engine 1.

[0021]

[Table 1]

On the other hand, when determining the valve closing timing TC, first the load (accelerator depression amount) and the actual engine speed θ of the engine 1
Based on Table 2, the valve closing basic advance amount TCBSE is calculated from Table 2.

[0023]

[Table 2]

Subsequently, the valve closing timing TC is calculated by the following equation. TC = TCBSE + TTC + FTC + TRTC + BTC + N
TC + NETC + TDC where TTC: A / F correction advance amount during transition FTC: Combustion temperature correction advance amount TRTC: Traction control correction advance amount BTC: Intake brake control advance amount during deceleration NTC: Corrected advance amount at knocking NETC: Corrected advance amount for air amount control TDC: Corrected advance amount for change over time of actuator After that, at step 1011 the drive of the intake control valve 2 is instructed, and then the process is terminated. .. When the driving of the intake control valve 2 is instructed, a driving signal is output to the electromagnetic coils 25a and 25b at a timing corresponding to the valve opening timing TO and the valve closing timing TC by another routine (not shown). Table 1,
Table 2 is an excerpted description of a part of the table stored in the ROM 33 that corresponds to a part of the rotational speed θ. For an intermediate value of the represented rotational speed θ, for example, an ordinary calculation such as interpolation calculation is performed. The valve opening timing TO calculated by the method is associated with the valve closing basic advance amount TCBSE.

Next, the control valve closing timing correction routine, which is the main part of the present invention, will be described. FIG. 11 shows the first
It is a flow chart showing a control valve closing timing correction routine of an example. When the processing is started, first, at step 101, the target idle speed θ1 is determined from the map A shown in FIG.
The initial value TCIDLE of the valve closing timing TC corresponding to is read and the valve closing timing TC is set to TCIDLE. In the following step 103, driving of the intake control valve 2 is instructed at the valve closing timing TC. Here, the valve closing timing TC is represented by an advance amount with respect to the bottom dead center BDC. Therefore, as the numerical value of the valve closing timing TC increases, the intake control valve 2 is closed earlier, and the output torque of the engine 1 decreases.

Next, at step 105, the actual engine speed θ
In step 107, the difference between the read actual engine speed θ and the target idle speed θ1 is Δθ.
Is calculated. In the subsequent step 109, the rotation speed difference Δ
It is determined whether θ is equal to or less than the allowable value α. If it is determined that the allowable value α is not less than or equal to the allowable value α, the process proceeds to the subsequent step 111.
In step 111, the valve closing timing correction amount ΔIDLE corresponding to the rotation speed difference Δθ is read from the map B shown in FIG. In the following step 113, the valve closing timing correction amount ΔIDLE is added to the currently set valve closing timing TC, and this is newly set as the valve closing timing TC. Further Step 1
In 15, the intake control valve 2 is set at the newly set closing timing TC.
Is instructed to drive, and the process proceeds to step 105. Thereafter, the loop of steps 105 to 115 repeats the correction of the valve closing timing TC until the rotational speed difference Δθ becomes equal to or less than the allowable value α.

On the other hand, if it is determined in step 109 that the rotational speed difference Δθ is equal to or less than α, the process proceeds to step 117.
At step 117, the initial value TCIDL of the valve closing timing TC
Rewrite E with the valve closing timing TC at that time, and replace this with RAM
Store in 34 and return to the main routine. When this routine operates again, the initial value TCIDLE is read from the RAM 34 in step 101, and the map closing A is executed as the valve closing timing TC regardless of the map A.

Here, the maps A and B are both in the ROM 3
It is stored in 3. The closing timing TC of the intake control valve 2 is set to be delayed as the actual engine speed θ becomes lower or the target idle speed θ1 becomes higher.
On the other hand, the valve opening timing TO is set by another routine (not shown).
When the engine 1 is idling, it is fixed at a predetermined position near the bottom dead center BDC. Therefore, the lower the actual engine speed θ, the longer the intake time of the cylinders 5 to 8 to improve the output torque, and the actual engine speed θ can approach the target idle speed θ1.

As described above, in this embodiment, the intake time of each cylinder 5-8, that is, the air-fuel mixture to be sucked, is controlled by the intake control valve 2 provided for each of the plurality of intake passages 13a communicating with the cylinders 5-8. The amount is individually adjusted and the actual engine speed θ is controlled to the target idle speed θ1. Here, the intake control valve 2 is
Since the cylinders are provided in the vicinity of the cylinders 5 to 8 from the position where the ISCV is provided in the conventional internal combustion engine, the actual engine speed θ
It is possible to reduce the delay time of feedback control based on. The intake control valve 2 is provided for each cylinder 5-8. Therefore, it is possible to make the delay time uniform for each cylinder even though the four intake passages 13a have different lengths.

Therefore, in this embodiment, the actual engine speed θ can be controlled to the target idle speed θ1 with high accuracy and stability during idling. Therefore, if the present embodiment is applied, it is possible to improve the fuel efficiency of the internal combustion engine by setting the target idle speed θ1 to an extremely small value immediately before the engine stall occurs. Further, in this embodiment, since the ISCV and the bypass passage are not provided, the structure near the throttle valve 14 can be simplified.

In the first embodiment, the four intake control valves 2
Are controlled to the same valve closing timing TC, but the valve closing timing TC of each intake control valve 2 may be different for each cylinder. By changing the closing timing TC of the intake control valve 2 for each cylinder, it is possible to reduce the output torque of some cylinders to below the engine stall occurrence limit and improve the fuel consumption during idling. I know.

FIG. 14 is a flow chart showing a control valve closing timing correction routine of the second embodiment. In this routine, a pair of intake control valves 2 belonging to the first cylinder 5 and the fourth cylinder 8 (provisionally referred to as the intake control valve 2a in the description of the routine) and a pair of intake control valves 2 belonging to the second cylinder 6 and the third cylinder 7 are provided. Intake control valve 2 (in the description of this routine, the intake control valve 2b
It is different from the closing time). That is, when the process is started, in step 201, the pair of intake control valves 2
The initial value TCIDLEa of the valve closing timing TCa for a is
It is read from the map C shown in FIG. Then step 20
3, the valve closing timing TCb for the pair of intake control valves 2b
The initial value TCIDLEb of is also read from the map C.

Next, at step 205, each intake control valve 2
After instructing the driving of a and 2b, the actual engine speed θ is read in step 207, and the speed difference Δθ from the target idle speed θ1 is calculated in step 209. Step two
When it is determined in step 11 that Δθ ≦ α (allowable value) is not satisfied, the correction amount ΔIDLE corresponding to the rotational speed difference Δθ is read from the map B in step 213. In the following steps 215 and 217, the valve closing timing TCa is set with the correction amount ΔIDLE.
And TCb are corrected, and in step 219, the drive of each intake control valve 2a, 2b is instructed.

When it is determined in step 211 that the rotational speed difference Δθ is less than or equal to the allowable value α, the process proceeds to steps 221, 223 in order, and the initial values TCIDLE of the valve closing timings TCa, TCb are set.
a, TCIDLEb valve closing timing TCa, TC at that time
Rewrite in b and return to the main routine.

In this embodiment, as shown in FIG. 15, the initial value TCIDLEa of the valve closing timing TCa is made larger than the initial value TCIDLEb of the valve closing timing TCb. Therefore, the intake air-fuel mixture for the fourth cylinders 5 and 8 can be made smaller than the engine stall occurrence limit to further improve the fuel efficiency.

When the cylinders 5 to 8 are divided into groups as in this embodiment and the intake air amount of a specific cylinder is made extremely small, the fluctuation rate of the actual engine speed θ (rotation speed It is desirable that the fluctuation rate does not become excessive. Therefore, the control valve closing timing correction routine of the third embodiment shown in FIG. 16 may be applied to the engine 1 having a high rotation fluctuation rate.

In the third embodiment, steps 301 to 319 correspond to steps 201 to 219 of the second embodiment.
Since the configuration is similar to the above, detailed description will be omitted. When it is determined in step 311 that the rotational speed difference Δθ is less than or equal to the allowable value α, the process proceeds to step 321, and the rotational fluctuation rate during the period in which the crankshaft makes one rotation calculated by another routine (not shown) falls within the allowable range. Determine if there is. If the rotation fluctuation rate is not within the allowable range, the routine proceeds to step 323, where the valve closing timing correction amount ΔH (> 0) corresponding to the rotation fluctuation rate is read from the map D shown in FIG. In the following step 325, the valve closing timing correction amount ΔH is subtracted from the currently set valve closing timing TCa, and this is newly added to the valve closing timing T
Set as Ca. In the subsequent step 327, the intake control valves 2a and 2a are respectively set at the newly set valve closing timing TCa and the valve closing timing TCb set in step 317.
Instruct to drive b. In the loop including steps 321 to 327, the correction of the valve closing timing TCa is repeated until the rotation fluctuation rate falls within the allowable range. That is, the valve closing timing TCa is set to be larger than the valve closing timing TCb in advance, but each time step 325 is repeated, the valve closing timing TCa becomes smaller, the difference from the valve closing timing TCb becomes smaller, and the rotation fluctuation rate becomes smaller. Become.

On the other hand, when it is determined in step 321 that the rotational fluctuation rate is within the allowable range, steps 331 and 333 are performed.
To the initial value TCI of the valve closing timings TCa and TCb.
The closing timing TC of DLEa and TCIDLEb at that time
Rewrite with a and TCb to return to the main routine. By preventing the rotation fluctuation rate from becoming excessive in this way, stable control can be executed.

Further, it is desirable to apply the fourth embodiment shown in FIG. 18 to the engine 1 in which the torque fluctuation between the cylinders 5 to 8 is large. In the fourth embodiment, the valve closing timings TCi (i = 1 to 4) of the first to fourth cylinders 5 to 8 are individually controlled.
When the process is started, in step 401, each valve closing timing TCi is set to an initial value TCIDLEi (i = 1 to 4) based on a map (not shown) similar to the maps A and C. Subsequently, in step 403, driving of the intake control valve 2 is instructed. Thereafter, each valve closing timing TCi is set to the valve closing timing correction amount ΔID of the map B until the rotational speed difference Δθ becomes equal to or less than the allowable value α by a loop including steps 405 to 415.
Correct with LE.

When the rotational speed difference Δθ becomes equal to or less than the allowable value α and the routine proceeds to step 417, the actual torque value Ti for each cylinder is read based on the signal from the torque sensor 37. In the following step 419, the actual torque values Ti are compared with each other to determine whether the inter-cylinder torque fluctuation is within the allowable range. As the method for determining the inter-cylinder torque fluctuation, a method of determining the average torque of each cylinder 5-8 as a reference torque, and a method of determining the cylinder 5-8
Various methods such as a method of selecting any one of the cylinders and determining it as the reference torque, a method of determining the target torque as the reference torque, etc.

When it is judged that the inter-cylinder torque fluctuation is out of the allowable range, in the subsequent step 421, the cylinders 5 to 8 are selected so that the difference between the actual torque value Ti and the reference torque is the largest.
Next, at step 423, the torque difference ΔTn is calculated by subtracting the actual torque value Tn (n is any one of 1 to 4) of the cylinders 5 to 8 from the reference torque, and based on this, the torque difference ΔTn is calculated.
The valve closing timing correction amount ΔHn is read from the map E of 9. In the following step 425, the currently set valve closing timing T
The valve closing timing correction amount ΔHn is added to Cn, and this is newly set as the valve closing timing TCn. Further, in the following step 427, driving of each intake control valve 2 is instructed, and the process proceeds to step 417. Thereafter, the loop of steps 417 to 427 repeats the correction of the valve closing timing TCn until the inter-cylinder torque fluctuation falls within the allowable range. Note that n may change during the repetition of this loop.

On the other hand, when it is determined in step 419 that the inter-cylinder torque fluctuation is within the allowable range, the process proceeds to step 429. In step 429, the initial value TCIDLEi of each valve closing timing TCi is rewritten with the valve closing timing TCi at that time, and the process returns to the main routine.

In the present embodiment, for example, when the torque difference ΔTn is positive (there are cylinders 5 to 8 having a small actual torque value Ti), the closing timing TCn of the intake control valve 2 in the cylinders 5 to 8 concerned. Can be corrected to decrease, that is, the valve closing timing TCn can be delayed to increase the actual torque value Tn. Therefore, even in the engine 1 in which the torque fluctuation between the cylinders 5 to 8 is large, the actual torque values Ti of the cylinders 5 to 8 can be made uniform, and the rotation fluctuation rate can be further improved. Torque difference ΔTn
The same is true when is negative. Therefore, the target idle speed θ1 can be set lower to improve fuel economy.

Next, in the explosion stroke of each cylinder 5-8,
The actual engine speed θ of the engine 1 detected individually based on the crankshaft rotation speed at that time {hereinafter, each cylinder 5-8
A description will be given of an embodiment that is effective for the engine 1 in which there is a large variation in the rotational speed θi (described as i = 1 to 4)}. 20, 2
1 is a flow chart showing the opening / closing control processing of the intake control valve of the fifth embodiment.

The processing of steps 501 to 525 is the same as the processing of steps 1001 to 415 of the fourth embodiment shown in FIGS. 10 and 18, so detailed description will be omitted. However, the return position after valve closing timing correction is shown in FIG.
Slightly different from When it is determined in step 519 that the rotational speed difference Δθ is equal to or less than the allowable value α, the process proceeds to step 527, and the initial value TCIDLEi of each valve closing timing TCi is rewritten with the valve closing timing TCi at that time. Continued Step 529
Then, the rotational speed θi of each cylinder 5-8 is read, and step 5
At 31, the rotational speed difference Δθi is calculated by subtracting each rotational speed θi from the target idle rotational speed θ1.

Next, when proceeding to step 533, FIG.
From the map F, the valve closing timing correction amount ΔKi corresponding to the rotational speed difference Δθi of each cylinder 5-8 is read. In the following step 535, the currently set valve closing timings TCi
Is added to the valve closing timing correction amount ΔKi, and this is newly set as the valve closing timing TCi. Further, in the following step 537, the drive of each intake control valve 2 is instructed, and the process proceeds to step 539.

In step 539, it is determined whether the engine 1 is in the idle state. If it is not in the idle state, the process proceeds to steps 503 and 505 to calculate the control valve opening / closing timing from Tables 1 and 2, and if it is still in the idle state, the process proceeds to the following step 541. In step 541, it is determined whether the target idle speed θ1 has been changed due to, for example, a change in the air conditioner load. If there is a change, the process proceeds to step 509 to calculate the target idle speed θ1 again, while if there is no change, the process proceeds to step 529.
Move to. In this case, the rotation speed θi of each cylinder 5-8 can be brought close to the target idle rotation speed θ1 by the loop including steps 529 to 541. For this reason, it becomes possible to significantly improve the rotational fluctuation rate of the engine 1 and set the target idle speed θ1 to be extremely small.

In the fifth embodiment, step 53
At 1, the difference in rotation speed Δθi between the target idle rotation speed θ1 and the rotation speed θi (i = 1 to 4) of each cylinder 5-8 is detected, and this rotation speed difference Δ is detected by the loop including steps 529 to 541. Although θi is eliminated, the rotational speed θi of each cylinder 5-8 is compared with each rotational speed θi detected before 720 ° CA in step 531 to eliminate this rotational speed difference. May be.

Further, in each of the above embodiments, the pattern of FIG. 6 in which only the valve closing timing TC is corrected has been described. However, the valve closing timing TC is opened in the same manner as the valve closing timing TC is advanced (increase correction) in each of the above described embodiments. If the valve timing TO is retarded (decreased), FIG.
The control of the pattern can be executed, and the valve closing timing TC
By correcting both the valve opening timing TO and the valve opening timing TO, it is possible to execute the control in the pattern of FIG. Further, if the intake control valve 2 is controlled to be partially opened (the pattern in FIG. 9), the change in the intake air-fuel mixture amount with respect to the change in the valve closing timing TC or the valve opening timing TO becomes small, and highly accurate control can be executed. it can. Furthermore, the present invention is not limited to the above-mentioned respective embodiments, and various embodiments other than the above-described respective embodiments can be appropriately combined, applied to a 6-cylinder engine, and the like.

[0050]

As described above in detail, in the intake control device of the present invention, the amount of the air-fuel mixture sucked into each cylinder is controlled by the intake control valve provided for each of the plurality of intake passages communicating with each cylinder. Is adjusted to control the engine speed to the target idle speed. Since the intake control valve is provided closer to each cylinder than the conventional ISCV, the delay time of feedback control based on the engine speed can be shortened. Further, since the intake control valve is provided for each cylinder, the delay time in the feedback control system of each cylinder can be made uniform.

Therefore, in the present invention, the engine speed can be controlled to the target idle speed with high accuracy and stability during idling. Therefore, if the present invention is applied, the idle speed of the internal combustion engine can be set to an extremely small value immediately before the engine stall occurs, and the fuel consumption of the internal combustion engine can be improved.

Further, if the present invention is applied, it is not necessary to provide the ISCV, and the structure in the vicinity of the throttle valve can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment.

FIG. 2 is a sectional view showing a configuration of an intake control valve shown in FIG.

3 is a cross-sectional view taken along line I-I shown in FIG.

4 is a cross-sectional view taken along the line JJ shown in FIG.

FIG. 5 is an explanatory diagram of opening control of an intake control valve.

FIG. 6 is a time chart showing a pattern for controlling only the valve closing timing of the embodiment.

FIG. 7 is a time chart showing a pattern for controlling only the valve opening timing of the embodiment.

FIG. 8 is a time chart showing a pattern for controlling the valve opening timing and the valve closing timing of the embodiment.

FIG. 9 is a time chart showing a pattern for performing partial open control of the intake control valve of the embodiment.

FIG. 10 is a flow chart showing a main routine of opening / closing control processing of the intake control valve in the first to fourth embodiments.

FIG. 11 is a flow chart showing a control valve closing timing correction routine of the first embodiment.

FIG. 12 is a map showing a relationship between a target idle speed and a valve closing timing initial value in the first embodiment.

FIG. 13 is a map showing a relationship between a rotation speed difference and a closing timing correction amount in the first embodiment.

FIG. 14 is a flowchart showing a control valve closing timing correction routine of the second embodiment.

FIG. 15 is a map showing a relationship between a target idle speed and a valve closing timing initial value in the second embodiment.

FIG. 16 is a flowchart showing a control valve closing timing correction routine of the third embodiment.

FIG. 17 is a map showing the relationship between the rotation fluctuation rate and the valve closing timing correction amount according to the third embodiment.

FIG. 18 is a flow chart showing a control valve closing timing correction routine of a fourth embodiment.

FIG. 19 is a map showing the relationship between the torque difference and the valve closing timing correction amount in the fourth embodiment.

FIG. 20 is a flowchart showing an intake valve opening / closing control process of a fifth embodiment.

FIG. 21 is a flowchart showing an intake valve opening / closing control process of a fifth embodiment.

FIG. 22 is a map showing the relationship between the rotation speed difference and the valve closing timing correction amount in the fifth embodiment.

FIG. 23 is a diagram illustrating the configuration of the present invention.

[Explanation of symbols]

1 ... Engine 2 ... Intake control valve
3 ... Control circuit 5, 6, 7, 8 ... Cylinder 11 ... Intake valve
13 ... Intake manifold 13a ... Intake passage 14 ... Throttle valve
21 ... Circular valve plate 35 ... Crank angle sensor 36 ... Rotation speed sensor
37 ... Torque sensor 38 ... Intake pipe pressure sensor 39 ... Throttle sensor
40 ... Water temperature detection sensor 42 ... Throttle position sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yurio Nomura 1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd. (72) Inventor Hideki Obayashi 1-1-chome, Showa town, Kariya city, Aichi prefecture NIDEC Co., Ltd. (72) Inventor Tokio Obama 1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. An intake passage ensuring means for ensuring a predetermined intake passage when an accelerator operation is not performed, and a plurality of intake passages that are provided for each of a plurality of intake passages communicating with each cylinder of an internal combustion engine. A plurality of intake control valves for opening and closing passages; an open / close drive means for opening and closing each intake control valve; a rotation speed detection means for detecting an engine speed of the internal combustion engine; Controlling the opening / closing drive means on the basis of the difference between the engine speed of the internal combustion engine detected by the number detecting means and a predetermined target idle speed to adjust the amount of the air-fuel mixture sucked into each cylinder. Thus, an intake control device for an internal combustion engine, comprising: an opening / closing control unit that brings the engine speed closer to the target idle speed.