JPH11148381A - Idle speed controller for internal combustion engine with variable valve timing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unstable rotation of an internal combustion engine at the time of idling, so as to prevent engine stall by conducting ISC corresponding to the number of failures in variable valve timing mechanisms (VVT) at the time of failure of the VVTs in the internal combustion engine. SOLUTION: The targeted rotational speed (S130) of an ISC and the opening of an ISCV (S135) when one VVT has abnormality in timing advance ('NO' at S110 or 'YES' at S120) are set larger (S140, S145) than those when all VVTs are normal ('NO' at S100 and S120), they are set further larger (S150, S155) when two VVTs have abnormality in timing advance ('YES' at S100 and S110). The number of the abnormal VVTs are reflected in the targeted rotational speed of the ISC and the opening of the ISCV, thus it is possible to prevent idle rotation from becoming unstable regardless of the number of the abnormal VVTs, and prevent engine stall effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control system for an internal combustion engine having a variable valve timing mechanism, and more particularly, to one or both of an intake valve and an exhaust valve in each of a plurality of banks provided in the internal combustion engine. The present invention relates to an internal combustion engine idle speed control device that includes a variable valve timing mechanism that adjusts timing and that controls the internal combustion engine speed during idling to a target speed.

[0002]

2. Description of the Related Art When an internal combustion engine used in a vehicle or the like is idling, it is drawn into the internal combustion engine bypassing a throttle valve so as to obtain an appropriate idle speed according to the operating state of the internal combustion engine. An idle speed control device (idle speed control: ISC) for automatically adjusting the amount of air is known.

In such an internal combustion engine, an internal combustion engine having a variable valve timing mechanism for adjusting the valve timing of an intake valve or an exhaust valve to efficiently operate the internal combustion engine according to the operating state is known. Are known.

In this variable valve timing mechanism, the actuator is driven to set the valve timing position in two stages according to the operating state of the internal combustion engine, such as when the internal combustion engine is idling, rotating at a low speed, or under a high load.
Alternatively, control for switching to multiple stages or more or for continuous switching is performed. The opening timings of the intake valve and the exhaust valve partially overlap, and the amount of overlap is automatically adjusted by the operation of the actuator.

[0005] If the variable valve timing mechanism fails, an appropriate valve overlap amount cannot be realized in accordance with the operation state of the internal combustion engine. In particular, when a failure occurs during idling, in which the valve overlap becomes unnecessarily large, the internal EGR amount becomes large, causing unstable idling and possibly causing engine stall.

In order to solve such a problem, an idle speed control valve (I) for adjusting the amount of intake air supplied to the internal combustion engine during idling according to the deviation between the actual valve timing and the target valve timing.
A technique for correcting the opening of SCV) is known (Japanese Patent Application Laid-Open No. Hei 7-119526). That is, if the valve overlap amount becomes large due to the failure of the variable valve timing mechanism, a correction that the ISCV is greatly opened is performed accordingly, and the idle rotation is stabilized.

[0007]

However, there are a plurality of banks such as a V-type engine, and each of the banks has
In the case of an internal combustion engine equipped with a variable valve timing mechanism,
As described above, the ISC depends on the valve overlap amount.
Only by adjusting V, it was found that when two or more variable valve timing mechanisms failed, the instability of the internal combustion engine rotation during idling could not be prevented, which could cause engine stall.

[0008] In the internal combustion engine provided with such a plurality of variable valve timing mechanisms, there is conventionally no known solution to the problem when two or more variable valve timing mechanisms fail.

According to the present invention, when a variable valve timing mechanism fails in an internal combustion engine provided with a plurality of variable valve timing mechanisms, an ISC is performed in accordance with the number of failed variable valve timing mechanisms, so that the internal combustion engine during idling is operated. It is an object of the present invention to prevent unstable rotation of the engine so as not to cause engine stall.

[0010]

According to a first aspect of the present invention, there is provided an idle speed control system for an internal combustion engine having a variable valve timing mechanism, wherein one or both of an intake valve and an exhaust valve are provided in each of a plurality of banks provided in the internal combustion engine. An idle speed control device for an internal combustion engine, comprising a variable valve timing mechanism for adjusting a valve timing and controlling a rotation speed of the internal combustion engine during idling to a target rotation speed, wherein an actual valve in each of the variable valve timing mechanisms is provided. In each of the valve timing detecting means for detecting the timing and the variable valve timing mechanism, the actual valve overlap estimated by the actual valve timing detected by the valve timing detecting means,
An overlap abnormality detecting means for detecting whether or not a target valve overlap estimated by a target valve timing is larger than an allowable amount; and If the actual valve overlap is larger than the target valve overlap by more than the allowable amount by the detection means, the internal combustion engine during idling is set in accordance with the number of variable valve timing mechanisms larger than the allowable amount. And an idle target rotation speed correcting means for correcting the target rotation speed.

Here, the idling target rotational speed correcting means includes:
The variable valve timing mechanism in which the actual valve overlap is larger than the target valve overlap exceeds the allowable amount is regarded as a variable valve timing mechanism in which an abnormality has occurred, that is, the target valve overlap amount is subtracted from the actual valve overlap amount. If the value exceeds the allowable amount, the variable valve timing mechanism is considered to be abnormal,
The target rotational speed of the internal combustion engine during idling is corrected in accordance with the number of abnormal variable valve timing mechanisms.

In an internal combustion engine provided with a plurality of variable valve timing mechanisms, a case where one variable valve timing mechanism becomes abnormal and a case where two or more variable valve timing mechanisms become abnormal have been described. As described above, in the correction of the same target rotation speed, even if the idle rotation is stabilized when only one variable valve timing mechanism is abnormal, the rotation is not stabilized with two or more but is stabilized only by a larger correction. .

In the idle speed control device for an internal combustion engine with a variable valve timing mechanism according to the first aspect, the number of abnormal variable valve timing mechanisms is reflected in the target rotation speed of the internal combustion engine at the time of idling. The idle rotation can be stabilized by appropriate correction when the variable valve timing mechanism is abnormal or when two or more variable valve timing mechanisms are abnormal. Even so, engine stall can be prevented.

More specifically, as set forth in claim 2, the idle target rotational speed correction means includes a variable valve timing mechanism in which the actual valve overlap is larger than the target valve overlap by more than an allowable amount. The target rotation speed of the internal combustion engine at the time of idling is corrected to be larger as the number is larger, thereby stabilizing the idle rotation by appropriate correction when the variable valve timing mechanism is abnormal. Thus, no matter how many variable valve timing mechanisms become abnormal, engine stall can be prevented.

According to a third aspect of the present invention, in the configuration of the idle speed control device for an internal combustion engine having the variable valve timing mechanism according to the first or second aspect, further, in any one of the variable valve timing mechanisms, the overlap is provided. If the abnormality detection means detects that the actual valve overlap is greater than the target valve overlap and is larger than the allowable amount, the idling is performed according to the number of variable valve timing mechanisms larger than the allowable amount. An idle speed control valve opening correction means for correcting the opening of the idle speed control valve for adjusting the intake air amount to the internal combustion engine at the time. In this way, when correcting the opening of the idle speed control valve as well as the target rotational speed, when the variable valve timing mechanism is abnormal, the idle rotation is stabilized by appropriate correction, especially immediately after the abnormality. The engine stall can be prevented no matter how many variable valve timing mechanisms become abnormal. Therefore, by providing the above-described idle speed control valve opening correction means in addition to the above-mentioned idle target rotation speed correction means, the idle rotation can be more effectively corrected by appropriate correction when the variable valve timing mechanism is abnormal. Can be stabilized, and engine stall can be prevented no matter how many variable valve timing mechanisms become abnormal.

Also, it is effective to use the idle speed control valve opening correction means alone instead of using the idle speed control valve opening correction means together with the idle target rotation speed correction means. That is,
As described in claim 4, in each of a plurality of banks provided in the internal combustion engine, a variable valve timing mechanism for adjusting valve timing of one or both of an intake valve and an exhaust valve is provided, and the number of rotations of the internal combustion engine during idling is provided. An idle speed control device for an internal combustion engine that controls the valve speed to a target speed, wherein the valve timing detecting means for detecting an actual valve timing in each of the variable valve timing mechanisms; and It is detected whether or not the actual valve overlap estimated by the actual valve timing detected by the timing detecting means is larger than an allowable amount with respect to the target valve overlap estimated by the target valve timing. An overlap abnormality detecting means; In any of the valve timing mechanism, the actual valve overlap at the overlapping abnormality detecting means with respect to the target valve overlap,
If it is detected that the value is larger than the allowable amount, the idle speed control valve for adjusting the intake air amount to the internal combustion engine during idling according to the number of variable valve timing mechanisms larger than the allowable amount is opened. And an idle speed control valve opening correction means for correcting the opening degree, and the above-described effect as the idle speed control valve opening correction means can be obtained.

More specifically, as set forth in claim 5, the idle speed control valve opening correction means includes a variable valve timing mechanism in which the actual valve overlap is larger than an allowable amount with respect to the target valve overlap. By correcting the opening of the idle speed control valve to a larger value as the number increases, the idle rotation can be stabilized by appropriate correction when the variable valve timing mechanism is abnormal. Thus, no matter how many variable valve timing mechanisms become abnormal, engine stall can be prevented.

Since the valve timing only needs to be able to estimate the valve overlap, for example, the advance amount of the intake valve may be used as the valve timing. That is, as set forth in claim 6, the valve timing detection means detects the advance amount of the intake valve of each bank as actual valve timing, and the overlap abnormality detection means corresponds to the actual valve overlap. The advance amount of the intake valve detected by the valve timing detection means may be used as the physical quantity to be performed, and the target advance angle of the intake valve may be used as the physical quantity corresponding to the target valve overlap.

As described above, if the intake valve is advanced,
It can be grasped directly and can be processed quickly. Since the valve timing only needs to be able to estimate the valve overlap, for example, the retard amount of the exhaust valve may be used as the valve timing. That is, as set forth in claim 7, the valve timing detecting means detects the retard amount of the exhaust valve of each bank as actual valve timing, and the overlap abnormality detecting means corresponds to the actual valve overlap. The retard amount of the exhaust valve detected by the valve timing detecting means may be used as the physical quantity to be performed, and the target retard amount of the exhaust valve may be used as the physical quantity corresponding to the target valve overlap.

As described above, if the exhaust valve is retarded,
It can be grasped directly and can be processed quickly. Of course, from the phase of the intake valve or the phase of the exhaust valve, or from the phase of both the intake valve and the exhaust valve when the valve timing of both the intake valve and the exhaust valve can be adjusted by the variable valve timing mechanism, The valve overlap amount may be estimated, and the valve overlap amount may be used.

The variable valve timing mechanism is not particularly limited. For example, a first rotating body interlocked with one of the two rotating shafts and a rotating body of the other of the two rotating shafts are provided. A second rotating body interlocked with an axis, and a relative rotation between the first rotating body and the second rotating body can variably set a rotational phase difference between the two rotating axes within an allowable range. May be adopted. With such a configuration, the valve timing can be switched steplessly in the internal combustion engine. Alternatively, for example, the valve timing may be switched in a stepwise manner by selecting and switching cams of the intake valve and the exhaust valve from a plurality of cams.

The allowable amount used when the overlap abnormality detecting means detects that the actual valve overlap is abnormally large with respect to the target valve overlap may be zero. That is, if the actual valve overlap is slightly larger than the target valve overlap, the variable valve timing mechanism may be detected as abnormal. Also, by setting a plus tolerance, the overlap abnormality detection means detects that the variable valve timing mechanism is normal if it is within a certain width, and that the variable valve timing mechanism is abnormal if it exceeds the width. You may make it.

[0023]

FIG. 1 is a schematic configuration diagram showing a gasoline engine system as one embodiment to which the present invention is applied.

V-type 6-cylinder engine 10 as an internal combustion engine
Includes a cylinder block 11 in which a plurality of cylinders are formed in a V-shape when viewed in the vertical direction of the drawing, a left cylinder head 12L and a right cylinder head 12R connected to an upper portion of the cylinder block 11, respectively. A cylinder group LS and a right cylinder group RS are formed. Hereinafter, these cylinder groups will be referred to as banks. Note that the left bank LS has 2
The fourth (# 2), fourth (# 4) and sixth (# 6) cylinders belong to the right bank RS, and the first (# 1), third (# 3) and fifth (# 5) cylinders belong to the right bank RS. The cylinder belongs.

The engine 10 also includes a piston 13 which reciprocates substantially vertically in each cylinder of the cylinder block 11, and a lower end of each piston 13 is connected to a crankshaft 14. By moving up and down, the crankshaft 14 is rotated.

In the vicinity of the crankshaft 14,
A crank angle sensor 40 is provided. The crank angle sensor 40 includes a magnetic rotor (not shown) connected to the crankshaft 14 and an electromagnetic pickup (not shown). Here, teeth are formed at equal angles on the outer periphery of the magnetic rotor, and a pulse-like crank angle signal is generated each time the teeth pass in front of the electromagnetic pickup.

Further, after a reference position signal is generated by a cylinder discriminating sensor 42 to be described later, the number of generated crank angle signals from the crank angle sensor 40 is measured.
At 70 (described later), the rotation speed (engine speed NE) of the crankshaft 14 is calculated.

The space defined by the inner walls of each cylinder block 11, the cylinder heads 12L and 12R, and the top of the piston 13 functions as a combustion chamber 15 for burning an air-fuel mixture.
An ignition plug 16 for igniting the air-fuel mixture is disposed at the top of L and 12R so as to project into the combustion chamber 15. Distributors 18 are provided in the vicinity of the two exhaust-side camshafts 33L, 33R of the two cylinder heads 12L, 12R, respectively, and each distributor 18 is provided with the rotation of the two exhaust-side camshafts 33L, 33R. A cylinder discrimination sensor 42 for detecting a reference position signal generated at a predetermined rate is provided. The reference position signal is used for detecting the reference position of the crankshaft 14 and determining the cylinder.

Each ignition plug 16 is connected to a distributor 18 via a plug cord or the like (not shown). The high voltage output from the igniter 19 based on an ignition signal from an ECU 70 (described later) The gas is distributed to each spark plug 16 by each distributor 18 in synchronization with the crank angle.

Further, the cylinder block 11 is provided with a water temperature sensor 43 for detecting the temperature (cooling water temperature) THW of the cooling water flowing through the cooling water passage. further,
Each of the two cylinder heads 12L and 12R has an intake port 22 and an exhaust port 32. The intake port 22 is connected to the intake passage 20, and the exhaust port 32 is connected to the exhaust passage 30. ing. Each intake port 22 of the cylinder head 12 has an intake valve 2
1 is disposed, and an exhaust valve 31 is disposed at each exhaust port 32.

Then, each intake valve 2 of the left bank LS
A left intake camshaft 23L for opening and closing the intake valve 21 is disposed above the right bank R.
Above each intake valve 21 of S, a right intake side camshaft 23R for opening and closing the intake valve 21 is arranged. Also, each exhaust valve 31 of the left bank LS
A left-side exhaust-side camshaft 33L for opening and closing the exhaust valve 31 is disposed above the right bank RS.
Above each exhaust valve 31, a right exhaust camshaft 33R for opening and closing the exhaust valve 31 is disposed.

Further, both intake side camshafts 23L, 23L
At one end of the 3R, an intake-side timing pulley 27 is provided.
Are mounted, and both exhaust side camshafts 33L, 33
An exhaust-side timing pulley 34 is attached to one end of each R. And, each timing pulley 27, 3
4 is connected to the crankshaft 14 via a timing belt 35.

Therefore, when the engine 10 is operating,
Each camshaft 2 from the crankshaft 14 via a timing belt 35 and timing pulleys 27 and 34
The rotational driving force is transmitted to 3L, 23R, 33L, 33R, and the respective camshafts 23L, 23R, 33L, 33R rotate, whereby the respective intake valves 21 and the respective exhaust valves 31 are opened and closed. These valves 21, 31
Is synchronized with the rotation of the crankshaft 14 and the vertical movement of the piston 13, that is, in synchronization with a series of four strokes of the engine 10 including an intake stroke, a compression stroke, an explosion / expansion stroke, and an exhaust stroke. It is driven at the opening and closing timing.

Further, both intake side camshafts 23L, 2L
In the vicinity of 3R, cam angle sensors 44L and 44R are provided, respectively.
(Corresponding to a valve timing detecting means) is provided, and each of the cam angle sensors 44L, 44R includes a magnetic rotor (not shown) connected to both intake side camshafts 23L, 23R and an electromagnetic pickup (not shown). ). Further, a plurality of teeth are formed at equal angles on the outer periphery of the magnetic rotor, for example, a compression TD of a predetermined cylinder.
Before C, a pulse-like cam angle signal (displacement timing signal) accompanying the rotation of the intake-side camshaft 23 is detected between BTDC 90 ° to 30 °.

Further, in the gasoline engine system according to the present embodiment, the opening / closing timing of the intake valve 21;
That is, the variable valve timing mechanisms 50L, 5 driven by hydraulic pressure are respectively applied to the intake timing pulleys 27 of the left bank LS and the right bank RS in order to change the valve overlap amount by changing the valve timing.
OR (hereinafter referred to as “VVT”). The VVTs 50L and 50R change the displacement angles of the intake camshafts 23L and 23R with respect to the rotation of the crankshaft 14 (the intake timing pulley 27) to continuously (steplessly) adjust the valve timing of the intake valve 21. This is a mechanism for making changes.

Each of the VVTs 50L, 50R has a corresponding oil control valve 80L, 80L.
R (hereinafter referred to as “OCV”), an oil pump 64
L, 64R and oil filters 66L, 66R are connected. In the present embodiment, an actuator is configured by the OCVs 80L and 80R, the oil pumps 64L and 64R, and the like.

An air cleaner 24 is connected to the air intake side of the intake passage 20, and a throttle valve 26 which is opened and closed in conjunction with an accelerator pedal (not shown) is provided in the middle of the intake passage 20. ing. The intake air amount is adjusted by opening and closing the accelerator pedal.

In the vicinity of the throttle valve 26, a throttle sensor 4 for detecting the throttle opening TA is provided.
5 are provided. Further, the throttle valve 26
A surge tank 25 for suppressing intake pulsation is formed on the downstream side. The surge tank 25 is provided with an intake pressure sensor 46 for detecting an intake pressure PM in the surge tank 25. An injector 17 for supplying fuel to the combustion chamber 15 is provided near the intake port 22 of each cylinder. Each injector 17 is an electromagnetic valve that is opened by energization, and each injector 17 is supplied with fuel pumped from a fuel pump (not shown).

Therefore, when the engine 10 is operating,
The air filtered by the air cleaner 24 is taken into the intake passage 20, and fuel is injected from each injector 17 toward each intake port 22 at the same time as taking in the air. As a result, an air-fuel mixture is generated at the intake port 22, and the air-fuel mixture is sucked into the combustion chamber 15 with the opening of the intake valve 21 that is opened during the intake stroke.

The exhaust gas generated by the combustion in the combustion chamber 15 passes through the catalytic converter 28 provided in the exhaust passage 30 and is discharged into the atmosphere. In the present embodiment, the bypass passage 91 is provided so that the upstream side and the downstream side of the throttle valve 26 communicate with each other. An idle speed control valve (ISCV) 92 is provided in the bypass passage 91. When idling, the ISCV
The opening of the valve 92 is adjusted by the ECU 70, whereby the amount of intake air flowing through the bypass passage 91 is controlled, whereby the engine speed (idling speed) during idling is controlled.
Is controlled. In addition, ISCV92
Is driven by a solenoid (not shown), and this solenoid is driven by duty control by the ECU 70 as described later. Therefore, ISCV9
2 is adjusted to an opening degree according to the duty.

Next, the system configuration of the VVTs 50L and 50R will be described with reference to FIG. For convenience of explanation, FIG. 2 shows VVT50L in the left bank LS.
And the VVT 50R in the right bank RS, the cross section near the intake side camshaft 23 where the VVT 50 is disposed, and the entire control system of the VVT 50 are shown.

The control system of the VVT 50 includes a VVT 5
0, an OCV 80 for applying a driving force to the VVT 50,
An OCV based on input signals from various sensors such as a cam angle sensor 44 for detecting a cam angle signal and a cam angle sensor 44.
An ECU 70 is provided for performing VVT control for controlling the drive of the intake valve 21 to adjust the intake valve 21 to a target advance amount.

The VVT 50 is disposed between the intake side camshaft 23 and the intake side timing pulley 27,
The intake camshaft 23 is rotatably supported between the cylinder head 12 and the bearing cap 51. An intake-side timing pulley 27 is mounted in the vicinity of the distal end of the intake-side camshaft 23 so as to be relatively rotatable, and an inner cap 52 is provided with a hollow bolt 53 and a pin 54 at the distal end of the intake-side camshaft 23. Are attached so as to be integrally rotatable.

A housing 56 having a cap 55 is attached to the intake-side timing pulley 27 by bolts 57 and pins 58 so as to be integrally rotatable. With this housing 56, the tip of the intake-side camshaft 23 and the inner The entire cap 52 is covered. Further, on the outer periphery of the intake-side timing pulley 27, a number of external teeth 27a for mounting the timing belt 35 are formed.

The intake camshaft 23 and the intake timing pulley 27 are connected by a ring gear 59 interposed between the housing 56 and the inner cap 52. The ring gear 59 has a substantially annular shape, and is housed in a space S surrounded by the intake-side timing pulley 27, the housing 56, and the inner cap 52 so as to be able to reciprocate in the axial direction of the intake-side camshaft 23. . A large number of teeth 59 are provided on the inner and outer circumferences of the ring gear 59.
a, 59b are formed.

Correspondingly, a large number of teeth 52a, 52a are provided on the outer periphery of the inner cap 52 and the inner periphery of the housing 56.
56b are formed. These teeth 59a, 59b,
Both 52a and 56b are helical teeth whose tooth traces intersect with the axis of the intake-side camshaft 23 at a predetermined angle. That is, the teeth 52a and the teeth 59a mesh with each other, and the teeth 56b and the teeth 59b mesh with each other to form a helical spline.

The rotation of the intake-side timing pulley 27 is transmitted to the intake-side camshaft 23 via the housing 56 and the inner cap 52 due to the engagement. Also, each tooth 59a, 59b, 52a, 56
Since b is a helical tooth, when the ring gear 59 moves in the axial direction of the intake side camshaft 23, a twisting force is applied to the inner cap 52 and the housing 56, and the intake side camshaft 23 is attached to the intake side timing pulley 27. Move relative to

In the space S, a first hydraulic chamber 60 is provided at the distal end of the ring gear 59 for moving the ring gear 59 in the axial direction, and a second hydraulic chamber 61 is provided at the proximal end of the ring gear 59.
have. The bearing cap 51 has a first hydraulic pressure supply hole 51a and a second hydraulic pressure supply hole 51b. The first camshaft 23 has a first
A first hydraulic supply path 62 that connects the hydraulic supply hole 51a to the first hydraulic chamber 60 and a second hydraulic supply path 63 that connects the second hydraulic supply hole 51b to the second hydraulic chamber 61 are formed. .

The lubricating oil sucked up from the oil pan 65 by the hydraulic pump 64 is supplied to each of the hydraulic pressure supply holes 51a and 51b through the oil filter 66 at a predetermined pressure. In addition, each hydraulic supply path 60, 6
In order to selectively supply the hydraulic pressure to each of the hydraulic chambers 60 and 61 through the hydraulic pressure supply hole 1, an OCV 8 is provided in each of the hydraulic pressure supply holes 51 a and 51 b.
0 is connected.

The OCV 80 is a four-port directional control valve for switching the flow direction of lubricating oil by causing a plunger 83 driven by an electromagnetic actuator 81 and a coil spring 82 to reciprocate a spool 84 in the axial direction. Then, the electromagnetic actuator 81
However, the duty is controlled to adjust the opening degree, and the magnitude of the hydraulic pressure supplied to each of the hydraulic chambers 60 and 61 is adjusted.

The casing 85 of the OCV 80 has a tank port 85t, an A port 85a, a B port 85b, and a reservoir port 85r. The tank port 85t is connected to the oil pan 65 via the hydraulic pump 64, and the A port 85a is connected to the first hydraulic supply hole 5
1a and the B port 85b are connected to the second hydraulic pressure supply hole 51b. The reservoir port 85r is connected to the oil pan 65.

The spool 84 is a cylindrical valve body,
It has four lands 84a for sealing the flow of the lubricating oil between the two ports, a passage 84b communicating between the two ports and allowing the flow of the lubricating oil, and two passages 84c.

In the VVT 50 having these configurations, OVT
When the drive of the CV 80 is controlled and the spool 84 is moved to the left in the drawing, the passage 84b
t and the A port 85a, and the first hydraulic pressure supply hole 51a
Is supplied with lubricating oil. Then, the first hydraulic pressure supply hole 51a
Is supplied to the first hydraulic chamber 60 via the first hydraulic pressure supply path 62, and the hydraulic pressure is applied to the distal end side of the ring gear 59.

At the same time, the passage 84c communicates between the B port 85b and the reservoir port 85r, and the lubricating oil in the second hydraulic chamber 61 is supplied to the second hydraulic supply path 63, the second hydraulic supply hole 51b, and the OCV 80. Is discharged to the oil pan 65 through the B port 85b and the reservoir port 85r.

Accordingly, the ring gear 59 is moved while rotating to the base end side (right side in the drawing) by the hydraulic pressure applied to the front end side, and twist is given to the intake side camshaft 23 via the inner cap 52. . As a result, the rotational phase (displacement angle) of the intake side camshaft 23 with respect to the intake side timing pulley 27 (crankshaft 14) is changed (displaced), and the intake side camshaft 23 is shifted from the most retarded angle to the most advanced angle. To the intake valve 21
Is advanced.

When the valve opening timing is advanced,
The valve overlap amount at which the intake valve 21 and the exhaust valve 31 are simultaneously opened increases. The ring gear 59
Is restricted by the ring gear 59 abutting on the intake-side timing pulley 27. When the ring gear 59 abuts on the intake-side timing pulley 27 and stops, the valve opening timing of the intake valve 21 is adjusted. It becomes the fastest and the valve overlap amount becomes the maximum.

On the other hand, when the drive of the OCV 80 is controlled and the spool 84 is moved rightward in the drawing, the passage 84
b communicates between the tank port 85t and the B port 85b,
Lubricating oil is supplied to the second hydraulic pressure supply hole 51b. And
The lubricating oil supplied to the second hydraulic pressure supply hole 51b is supplied to the second hydraulic pressure chamber 61 via the second hydraulic pressure supply passage 63, and the hydraulic pressure is applied to the base end side of the ring gear 59.

At the same time, the passage 84c communicates between the A port 85a and the reservoir port 85r, and the lubricating oil in the first hydraulic chamber 60 is supplied to the first hydraulic supply path 62, the first hydraulic supply hole 51a, and the OCV 80. Is discharged to the oil pan 65 through the A port 85a and the reservoir port 85r.

Accordingly, the ring gear 59 is moved while rotating to the distal end side (leftward in the drawing) by the hydraulic pressure applied to the proximal end side, so that the intake side camshaft 23 is twisted in the opposite direction via the inner cap 52. Granted. As a result,
Intake side timing pulley 27 (crankshaft 14)
, The rotational phase (displacement angle) of the intake camshaft 23 is changed (displaced), and the intake camshaft 23 is displaced from the most advanced angle to the most retarded angle, and the valve opening timing of the intake valve 21 is changed. Is retarded. That is,
The amount of advance is reduced.

In this manner, the advance amount of the valve opening timing of the intake valve 21 is reduced, so that the intake valve 21
And the exhaust valve 31 are simultaneously opened, the valve overlap amount is small or zero. The movement of the ring gear 59 toward the distal end is regulated by the contact of the ring gear 59 with the housing 56. When the ring gear 59 contacts the housing 56 and stops, the valve opening timing of the intake valve 21 becomes the latest. (The most retarded angle) and the amount of advanced angle becomes the minimum.

The valve timing of the intake valve 21 changed by the VVT 50 includes a cam angle signal (displacement timing signal) output from the cam angle sensor 44 and a crank angle signal (reference timing signal) output from the crank angle sensor 40. ).

That is, for example, after the displacement timing signal is input to the ECU 70, the first input crank angle signal is recognized as the reference timing signal, and the reference timing signal is input after the displacement timing signal is input. Is measured using the engine speed NE. Then, the actual displacement angle VTB of the intake-side camshaft 23 with respect to the crankshaft 14 is calculated by converting the time into a displacement angle using the relationship between the known time and the crank angle.

Subsequently, the engine 10 according to the present embodiment
Will be described with reference to a control block diagram shown in FIG. The control system of the engine 10 includes an electronic control unit 70
(Hereinafter simply referred to as “ECU”). In the present embodiment, the ECU 70 performs processing as an idling target rotation speed correction unit (steps S100, S110, S120, S130, S140,
S150) and processing as an idle speed control valve opening correction means (step S100, which will be described later).
(S110, S120, S135, S145, S155)
And running.

The ECU 70 has a ROM 71 which stores various control programs such as VVT control, ignition timing control, fuel injection control, and control at the time of failure, and a map for calculating a target value corresponding to various conditions. . Also,
The ECU 70 executes a calculation process based on the control program stored in the ROM 71,
And a backup RAM 74 for temporarily storing various data stored in the RAM 73 when power supply is stopped, and the like.

Then, the CPU 72, the ROM 71, and the RAM
73 and a backup RAM 74 include a bidirectional bus 75
And the input interface 76 and the output interface 77.

The input interface 76 includes a crank angle sensor 40, a cylinder discrimination sensor 42, a water temperature sensor 43,
A left cam angle sensor 44L, a right cam angle sensor 44R, a throttle sensor 45, an intake pressure sensor 46, and the like are connected. If the signal output from each sensor is an analog signal, the signal is converted into a digital signal by an A / D converter (not shown), and then converted into a digital signal.
Is output to

The output interface 77 includes an injector 17, an igniter 19, and OCVs 80L and 80.
External circuits such as R and ISCV 92 are connected, and the operation of these external circuits is controlled based on the calculation result of the control program executed by the CPU 72. Note that V
The VT50L is controlled by driving the OCV80L, and the VT50R is controlled by the OCV80L.
The control is performed independently by controlling the driving of R.

Next, in the ISC performed when the engine 10 is idling, the valve timing control device VC
The operation when the VVTs 50L and 50R fail (failure) will be described.

FIG. 4 shows an IS executed by the ECU 70.
Of C, the target rotation speed N repeatedly performed every 16 ms
T and the opening dcal of ISCV92 (actually, ISCV9
9 is a flowchart showing a 16 ms routine for setting a duty that finally determines the opening degree of the second (also referred to as a final duty). Steps in the flowchart corresponding to each process are represented by “SＳ”.

When the process proceeds to this routine, it is determined whether the right bank advance fail flag xvvtf1 is on (ON) (S100). If the right bank advance fail flag xvvtf1 is on (“YE
S "), it is determined whether or not the left bank advance fail flag xvvtf2 is on (S110). Also, when the right bank advance fail flag xvvtf1 is not on (S
"NO" at 100), left bank advance fail flag xv
It is determined whether vtf2 is on (S120).

The right bank advance fail flag xvv
tf1 and left bank advance fail flag xvvtf2
ON / OFF is set by a VVT advance angle abnormality detection routine shown in FIG. Here, the VVT advance angle abnormality detection routine will be described.

First, the right target advance angle VTTR calculated for adjusting the VVT 50R based on the current operation state by the VVT control is read into the working memory (S20).
0) Then, the right actual advance angle VTBR is detected from the right cam angle sensor 44R as described above (S210).

Next, it is determined whether or not a value obtained by subtracting the right target advance angle VTTR from the right actual advance angle VTBR is equal to or smaller than the allowable value VVTS (S220). If VTBR-VTTR is equal to or smaller than the allowable value VVTS ("YES" in S220),
Regarding the VVT50R, it is determined that no advance abnormality has occurred, and the right bank advance fail flag xvvtf1 is set to OFF (S230). VTBR-VT
If TR exceeds the allowable value VVTS ("N" in S220)
O "), it is determined that the VVT 50R is abnormal in advance, and the right bank advance fail flag xvvtf1 is set to ON (S240).

Next, the left target advance angle VTTL calculated for adjusting the VVT 50L based on the current operation state by the VVT control is read into the working memory (S25).
0) Next, the left actual advance angle VTBL is detected from the left cam angle sensor 44L as described above (S260).

Next, it is determined whether a value obtained by subtracting the left target advance angle VTTL from the left actual advance angle VTBL is equal to or smaller than the allowable value VVTS (S270). If VTBL-VTTL is equal to or smaller than the allowable value VVTS ("YES" in S270),
Regarding the VVT 50L, it is determined that the advance angle abnormality has not occurred, and the left bank advance angle fail flag xvvtf2 is set to OFF (S280). VTBL-VT
If the TL exceeds the allowable value VVTS ("N" in S270
O "), it is determined that the VVT 50L is abnormal in advance, and the left bank advance fail flag xvvtf2 is set to ON (S290).

As described above, the right bank advance fail flag xvvtf1 and the left bank advance fail flag x
On / off of vvtf2 is set. Therefore, if the right bank advance fail flag xvvtf1 is on, it is understood that the VVT 50R is too advanced from the target, and if the left bank advance fail flag xvvtf2 is on, the VVT 50L is more advanced than the target. It turns out that it is too much. This excessive advance indicates that the advance amount of the intake valve 21 with respect to the exhaust valve 31 is too large, and the valve overlap amount is too large than the target.

Returning to the description of the processing in FIG. 4, if both the right bank advance fail flag xvvtf1 and the left bank advance fail flag xvvtf2 are off (“NO” in both S100 and S120), the target rotation speed NT Is set (S130), and the target rotation speed set value NTN of
0 is set to the expected VVT fail amount dvtf for correcting the opening of the CV 92 (S135).

The right bank advance fail flag xvv
When tf1 is off, left bank advance fail flag xvvt
When f2 is ON (“NO” in S100 and S1
20 (“YES”), or when the right bank advance fail flag xvvtf2 is on and the left bank advance fail flag xvvtf2 is off (“YE in S100”).
S "and" NO "in S110), the target rotational speed NT
The first abnormal time target rotational speed set value NTVTVTFL is set (S140), and the first abnormal time correction value D is added to the estimated VVT fail amount dvtf for correcting the opening of the ISCV 92.
The VTFL is set (S145).

The right bank advance fail flag xvv
tf1 and left bank advance fail flag xvvtf2
Are both ON ("YES" in both S100 and S110), the second abnormal target rotational speed set value NTVVTFH is set as the target rotational speed NT (S150), and the ISC
The second abnormal-state correction value DVTFH is set to the estimated VVT fail amount dvtf for correcting the opening of the V92 (S155).

The target rotational speed set value NTN, the first abnormal target rotational speed set value NTVVTFL, and the second abnormal target rotational speed set value NTVVTFH have a relationship represented by the following equation.

[0081]

[Expression 1] NTVVTHF>NTTVVTFL> N
TN> 0 The relationship between the first abnormal-time correction value DVTFL and the second abnormal-time correction value DVTFH is expressed by the following equation.

[0082]

DVTFH>DVTFL> 0 Step S135, Step S145 or Step S
After 155, the final duty dcal is calculated by the following equation.
Is calculated (S160), and the 16 ms routine is temporarily ended.

[0083]

## EQU3 ## dcal (i) = dthw (i) + dfb
(I) + dvtf (i) where dthw is a water temperature correction amount set according to the value of the cooling water temperature THW detected by the water temperature sensor 43, d
fb is a feedback correction amount described later, and the suffix (i) indicates a value at the present time.

Next, the setting of the feedback correction amount dfb will be described. FIG. 6 shows that every 180 ° crank angle,
9 shows a flowchart of a 180 ° CA routine for setting a feedback correction amount dfb.

In this routine, first, the actual engine speed NE calculated by measuring the frequency of occurrence of the crank angle signal from the crank angle sensor 40 in a routine not shown is shown.
Is determined to be equal to or higher than the target rotational speed NT (S30).
0). If NE ≧ NT (“YES” in S300),
In order to reduce the engine speed NE, as shown in the following equation, the feedback correction amount df obtained immediately before
A value obtained by subtracting the correction amount EDFB from b (i-1) is set as a new feedback correction amount dfb (i) (S
310).

[0086]

Dfb (i) = dfb (i−1) −EDFB Here, the subscript (i−1) means a value obtained one time before (i).

If NE <NT ("NO" in S300), to increase the engine speed NE,
As shown in the following equation, a value obtained by adding the correction amount EDFB to the feedback correction amount dfb (i-1) obtained immediately before is set as a new feedback correction amount dfb (i) (S320).

[0088]

Dfb (i) = dfb (i-1) + EDFB In this manner, the engine speed NE becomes the target engine speed NT.
Feedback control is performed so that

Further, based on the final duty dcal obtained in step S160, the opening of the ISCV 92 is duty-controlled by a "4ms routine" executed every 4ms shown in FIG.

First, the ECU 70 turns on the ISCV 92 solenoid so as to open the ISCV 92 (S400). Next, the timing at which the solenoid for the ISCV 92 is turned off is set in a timer built in the ECU 70 (S410), and the process is terminated once.

In the setting of the timer in step S410, the value of 4 ms × final duty dcal is set. That is, the value of the final duty dcal is 4 m
s is the value indicating the ratio of the solenoid ON time for the ISCV 92 within 4 s, and 4 ms × final duty d
After the lapse of cal time, the solenoid for ISCV 92 is turned off.

By the duty control performed in the 4 ms routine, the opening degree of the ISCV 92 is changed to the final duty d.
The opening is adjusted to an opening according to the value of cal. Therefore, the opening of the ISCV 92 increases as the estimated VVT fail amount dvtf constituting a part of the final duty dcal increases, and the opening of the ISCV 92 decreases as the estimated VVT fail amount dvtf decreases.

As described above, according to the present embodiment,
Steps S100, S110, S120, S130, S
140 and S150 (corresponding to the processing as the idling target rotation speed correction means), the two VVTs 50
When one of R and 50L is abnormal in the advance angle, the target rotational speed setting value NTN set as the target rotational speed NT of the engine 10 at the time of idling when both the VVTs 50R and 50L are normal. Is set as the target rotation speed NT, and when both VVTs 50R and 50L are abnormally advanced, the first set value is set when one of them is abnormally advanced. A second abnormal time target rotational speed set value NTVVTHF which is larger than the 1 abnormal time target rotational speed set value NTVVTFL is set as the target rotational speed NT.

That is, when the advance amount of the intake valve 21 becomes abnormally large and the valve overlap amount exceeds the target amount by more than the allowable amount VVTS, the number of abnormally advanced VVTs increases. Accordingly, the target rotation speed NT of the engine 10 during idling is corrected to be larger as the number is larger. As described above, the number of abnormal VVTs is reflected in the target rotational speed NT of the engine 10 during idling.
Even when one of the VVTs is abnormal, the idle rotation can be stabilized by appropriate correction, and engine stall can be prevented no matter how many VVTs become abnormal.

In the present embodiment, step S10
0, S110, S120, S135, S145, S15
5 (corresponding to the processing as the idle speed control valve opening correction means), two VVTs
If one of 50R and 50L is abnormal in advance angle,
I when both VVTs 50R and 50L are normal
When the opening of the SCV 92 is set to a larger opening, and both the VVTs 50R and 50L are abnormally advanced,
The opening is set to be larger than the opening of the ISCV 92 which is set when one of the two is abnormally advanced.

That is, if the advance amount of the intake valve is abnormally large and the valve overlap amount is larger than the target and exceeds the allowable amount VVTS, the amount of VVT having the abnormal advance angle is determined. And the larger the number, the more I
The opening of the SCV 92 is corrected to be larger. As described above, the number of abnormal VVTs is reflected in the opening of the ISCV 92. Therefore, even when only one VVT is abnormal, two V
Even when the VT is abnormal, by appropriately correcting the ISCV opening, it is possible to prevent the idling speed from becoming unstable, particularly immediately after the VVT becomes abnormal, and the target rotational speed NT
In addition to the above correction, the idle rotation can be more effectively stabilized, and the engine stall can be sufficiently prevented.

Further, in the present embodiment, the advance amount of the intake valve is used, and the valve overlap amount is estimated based on the advance amount. As described above, since the advance amount that can be captured directly is used, quick processing is possible.

The present invention is not limited to the above-described embodiment, and may be implemented as follows, with a part of the configuration being appropriately changed without departing from the spirit of the invention. In the above-described embodiment, the idling target rotational speed correcting means (steps S100, S110, S120, S13)
0, S140 and S150) and an idle speed control valve opening correction means (steps S100 and S100).
S110, S120, S135, S145, and S155) are used together, but they may be used alone. By the effect of the idle target rotation speed correction means or the idle speed control valve opening degree correction means itself, idle rotation can be stabilized and engine stall can be prevented.

The valve timing only needs to be able to estimate the valve overlap. Therefore, instead of the advance amount of the intake valve described above, for example, the retard amount of the exhaust valve may be used as the valve timing. In this way, if the amount of retardation of the exhaust valve is the same as the amount of advancement, it can be directly detected, and prompt processing can be performed. Of course, from the phase of the intake valve or the phase of the exhaust valve, or from the phase of both the intake valve and the exhaust valve,
The degree of valve overlap may be estimated, and the valve overlap amount may be used.

The allowable amount VVTS used in the abnormality detection in steps S220 and S270 may be zero. Also,
A plus allowable value VVTS may be set to detect that the VVT is normal if it is within a certain width, and that the VVT is abnormal if it exceeds the width.

In the above-described embodiment, an example in which the V-type engine 10 is employed as the internal combustion engine has been described. However, the present invention is applicable to any type of engine such as a horizontally opposed engine as long as it has a plurality of banks. it can. Further, the present invention can be applied not only to a gasoline engine but also to a diesel engine. The number of banks is not limited to two, but includes three or more.

In the above-described embodiment, the VVT 50 of the type in which the ring gear 59 moves is adopted as the variable valve timing mechanism.
(E.g., a vane-type VVT) may be employed.
Is not particularly limited. For example, the cam of the intake valve or the exhaust valve may be selected from a plurality of cams and switched to switch the valve timing in a stepwise manner. Further, another actuator may be used in place of the OCV 80.

In the above embodiment, the ECU 70
Has been described as executing a plurality of types of control as described above.
Data communication may be performed between the devices by the in-vehicle LAN.

[0104]

According to the first aspect of the present invention, the number of abnormal variable valve timing mechanisms as described above is reflected in the target rotational speed of the internal combustion engine during idling. Therefore, when only one variable valve timing mechanism is abnormal or when two or more variable valve timing mechanisms are abnormal, the idle rotation can be stabilized by appropriate correction. Even if the valve timing mechanism becomes abnormal, engine stall can be prevented.

According to a second aspect of the present invention, in accordance with the number of variable valve timing mechanisms that exceed the permissible amount and are larger than the permissible amount, the idling target engine speed correction means increases the number of the variable valve timing mechanisms so that the larger the number is, the more the internal combustion engine is idling. When the variable valve timing mechanism is abnormal, the idle speed can be stabilized by appropriate correction by correcting the target rotation speed to a larger value. Stalls can be prevented.

In the third aspect of the present invention, the idle speed control apparatus for an internal combustion engine with a variable valve timing mechanism according to the first or second aspect further includes a variable number of abnormal variable valve timing mechanisms as described above. An idle speed control valve opening correction means for correcting the opening of the idle speed control valve accordingly. Therefore, not only the target rotation speed but also the opening of the idle speed control valve can be corrected,
When the variable valve timing mechanism is abnormal, especially immediately after it becomes abnormal, the idle rotation can be more effectively stabilized, and no matter how many variable valve timing mechanisms become abnormal, engine stall can be prevented. Can be.

As described in claim 4, instead of using the idle speed control valve opening correction means together with the idle target rotational speed correction means, the idle speed control valve opening correction means may be used alone. No matter how many variable valve timing mechanisms become abnormal, there is the effect of stabilizing idle rotation, especially immediately after the abnormality, to prevent engine stall.

According to a fifth aspect of the present invention, the idle speed control valve opening correction means is responsive to the number of the variable valve timing mechanisms which are larger than the permissible amount. By correcting the valve opening to the larger one, when the variable valve timing mechanism is abnormal, the idle rotation can be stabilized by appropriate correction, and no matter how many variable valve timing mechanisms become abnormal, the engine Stalls can be prevented.

Further, as described in claim 6, the valve timing detecting means detects the advance amount of the intake valve of each bank as the actual valve timing, and the overlap abnormality detecting means corresponds to the actual valve overlap. The advance amount of the intake valve detected by the valve timing detecting means may be used as the physical quantity, and the advance amount of the target intake valve may be used as the physical quantity corresponding to the target valve overlap. That is, since the valve overlap amount increases as the valve timing of the intake valve advances, the valve overlap can be estimated from the advance amount of the intake valve. As described above, the advance amount of the intake valve can be directly grasped, and prompt processing can be performed.

Further, since the valve overlap amount increases as the valve timing of the exhaust valve is retarded, the valve overlap can be estimated from the retard amount of the exhaust valve. Therefore, as described in claim 7, the valve timing detecting means detects the delay amount of the exhaust valve of each bank as the actual valve timing, and the overlap abnormality detecting means detects the physical quantity corresponding to the actual valve overlap. Alternatively, the retard amount of the exhaust valve detected by the valve timing detecting means may be used, and the retard amount of the target exhaust valve may be used as the physical quantity corresponding to the target valve overlap. As described above, the amount of retardation of the exhaust valve can be directly detected, and prompt processing can be performed.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram illustrating a schematic configuration of a gasoline engine system according to an embodiment.

FIG. 2 is a schematic configuration diagram of a variable valve timing mechanism system in the gasoline engine system.

FIG. 3 shows an EC in the gasoline engine system.
FIG. 2 is a block diagram showing a control system of U.

FIG. 4 shows a target rotational speed NT executed by the ECU.
9 is a flowchart illustrating a “16 ms routine” for setting the ISCV and the opening degree dcal of the ISCV.

FIG. 5 is a flowchart showing a “VVT advance angle abnormality detection routine” executed by the ECU.

FIG. 6 shows a crank angle 18 executed by the ECU.
For each 0 °, the feedback correction amount dfb is set to “1”.
Flowchart showing "80 CA routine".

FIG. 7 is a flowchart showing a “4 ms routine” for performing duty control of an ISCV opening executed by the ECU.

[Explanation of symbols]

LS: left cylinder group (left bank), RS: right cylinder group (right bank), VC: valve timing control device, 1
0 ... V type engine, 11 ... Cylinder block, 12 ... Cylinder head, 12L ... Left cylinder head, 12R ...
Right cylinder head, 13 piston, 14 crankshaft, 15 combustion chamber, 16 spark plug, 17 injector, 18 distributor, 19 igniter, 20 intake passage, 21 intake valve, 22 intake port, 23 ... intake side camshaft, 23L ... left intake side camshaft, 23R ... right intake side camshaft,
24 ... air cleaner, 25 ... surge tank, 26 ... throttle valve, 27 ... intake-side timing pulley, 27a
... external teeth, 28 ... catalytic converter, 30 ... exhaust passage, 31
... Exhaust valve, 32 ... Exhaust port, 33L ... Left exhaust camshaft, 33R ... Right exhaust camshaft, 34
... Exhaust-side timing pulley, 35 ... Timing belt,
40 ... crank angle sensor, 42 ... cylinder discrimination sensor, 43
... water temperature sensor, 44 ... cam angle sensor, 44L ... left cam angle sensor, 44R ... right cam angle sensor, 45 ... throttle sensor, 46 ... intake pressure sensor, 50 ... variable valve timing mechanism (VVT), 50L ... left VVT, 50R
… Right side VVT, 51… bearing cap, 51a… first hydraulic supply hole, 51b… second hydraulic supply hole, 52… inner cap, 52a… teeth, 53… hollow bolt, 54… pin, 55… cap, 56… housing , 56b ... teeth,
57 bolt, 58 pin, 59 ring gear, 59
a, 59b, 52a, 56b ... teeth, 60 ... first hydraulic chamber,
61 ... second hydraulic chamber, 62 ... first hydraulic supply path, 63 ... second
Hydraulic supply path, 64: hydraulic pump, 64L, 64R: oil pump, 65: oil pan, 66: oil filter,
66L, 66R: oil filter, 70: electronic control unit (ECU), 71: ROM, 72: CPU, 73: RA
M, 74: backup RAM, 75: bidirectional bus, 7
6 Input interface, 77 Output interface, 80, 80L, 80R Oil control valve (OCV), 81 Electromagnetic actuator, 82 Coil spring, 83 Plunger, 84 Spool, 8
4a: land, 84b, 84c: passage, 85: casing, 85a: A port, 85b: B port, 85r
... Reservoir port, 85t ... Tank port, 91 ... Bypass passage, 92 ... Idle speed control valve (ISCV)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/22 301 F02D 41/22 301H

Claims (7)

[Claims] 1. A variable valve timing mechanism for adjusting valve timing of one or both of an intake valve and an exhaust valve in each of a plurality of banks provided in an internal combustion engine, and a target rotation speed of the internal combustion engine during idling. An idle speed control device for an internal combustion engine that controls the number of valves in each of the variable valve timing mechanisms; and a valve timing detection means in each of the variable valve timing mechanisms. An overlap abnormality that detects whether or not the actual valve overlap estimated by the actual valve timing detected at the time is larger than an allowable amount with respect to the target valve overlap estimated by the target valve timing. Detecting means; and the variable valve In any of the imaging mechanisms, if the actual valve overlap is detected to be larger than the allowable amount with respect to the target valve overlap by the overlap abnormality detecting means, the variable variable is set to be larger than the allowable amount. Idle speed control means for correcting the target speed of the internal combustion engine during idling according to the number of valve timing mechanisms. apparatus. 2. The idle target rotation speed correction means according to the number of variable valve timing mechanisms whose actual valve overlap is larger than an allowable amount with respect to the target valve overlap. 2. The idle speed control device for an internal combustion engine with a variable valve timing mechanism according to claim 1, wherein the target speed of the internal combustion engine at the time is corrected to a larger value. 3. The configuration of an idle speed control device for an internal combustion engine with a variable valve timing mechanism according to claim 1 or 2, further comprising: If it is detected that the valve overlap is larger than the target valve overlap and is larger than the allowable amount, according to the number of the variable valve timing mechanisms that are larger than the allowable amount, the internal combustion engine during idling is controlled. An idle speed control device for an internal combustion engine with a variable valve timing mechanism, comprising an idle speed control valve opening correction means for correcting an opening of an idle speed control valve for adjusting an intake air amount. 4. A variable valve timing mechanism for adjusting valve timing of one or both of an intake valve and an exhaust valve in each of a plurality of banks provided in the internal combustion engine, and controlling a rotational speed of the internal combustion engine during idling to a target rotational speed. An idle speed control device for an internal combustion engine that controls the number of valves in each of the variable valve timing mechanisms; and a valve timing detection means in each of the variable valve timing mechanisms. An overlap abnormality that detects whether or not the actual valve overlap estimated by the actual valve timing detected at the time is larger than an allowable amount with respect to the target valve overlap estimated by the target valve timing. Detecting means; and the variable valve In any of the imaging mechanisms, if the actual valve overlap is detected to be larger than the allowable amount with respect to the target valve overlap by the overlap abnormality detecting means, the variable variable is set to be larger than the allowable amount. Idle speed control valve opening correction means for correcting the opening of the idle speed control valve for adjusting the intake air amount to the internal combustion engine during idling according to the number of valve timing mechanisms. An idle speed control device for an internal combustion engine with a variable valve timing mechanism. 5. The idle speed control valve opening correction means according to the number of variable valve timing mechanisms in which the actual valve overlap exceeds the target valve overlap by more than an allowable amount, the larger the number is,
5. The idle speed control device for an internal combustion engine with a variable valve timing mechanism according to claim 3, wherein the opening of the idle speed control valve is corrected to be larger. 6. The valve timing detecting means detects an advance amount of an intake valve of each of the banks as actual valve timing, and the overlap abnormality detecting means detects the valve advance as a physical quantity corresponding to the actual valve overlap. Using the advance amount of the intake valve detected by the timing detection means,
The idle speed control device for an internal combustion engine with a variable valve timing mechanism according to any one of claims 1 to 5, wherein a target advance amount of the intake valve is used as a physical amount corresponding to the target valve overlap. 7. The valve timing detecting means detects a delay amount of an exhaust valve of each of the banks as actual valve timing, and the overlap abnormality detecting means detects the valve as a physical quantity corresponding to the actual valve overlap. Using the retard amount of the exhaust valve detected by the timing detecting means,
The idle speed control device for an internal combustion engine with a variable valve timing mechanism according to any one of claims 1 to 5, wherein a target retard amount of the exhaust valve is used as a physical quantity corresponding to the target valve overlap.