JPH08105337A - Internal combustion engine having variable cylinder mechanism - Google Patents

Abstract

PURPOSE: To sharply reduce a shock of an internal combustion engine having a variable cylinder mechanism at switching time from a cylinder resting mode to a whole cylinder mode. CONSTITUTION: An internal combustion engine is provided with a variable cylinder mechanism 48 which can switch a whole cylinder mode and a cylinder resting mode to/from each other, a variable cylinder control means 70 to control the variable cylinder mechanism 48, a fuel supply means FS which can supply fuel with every cylinder, a fuel supply control means 71 and an ignition timing control means 73 to control an ignition means 75. When the internal combustion engine 1 selects the cylinder resting mode, operation is set so as to stop fuel supply to resting cylinders through the fuel supply control means FS. Then, when a mode is switched to the whole cylinder mode from the cylinder resting mode, the fuel supply control means 71 states the fuel supply in order while giving a time difference, and the ignition timing control means 73 retards the ignition timing to a start of this fuel supply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine with a variable cylinder mechanism, which is switchable between an all cylinder mode in which all of a plurality of cylinders are operated and a cylinder deactivation mode in which the operation of some cylinders is stopped. .

[0002]

2. Description of the Related Art In recent years, in an internal combustion engine (engine) used in a vehicle such as an automobile, at the time of low load operation, some cylinders of a plurality of cylinders of the engine are stopped so that fuel consumption is reduced and high fuel consumption is improved. An engine with a so-called variable cylinder mechanism (or an engine with a cylinder deactivation mechanism) that operates all cylinders during load operation to improve drivability.
Has been put to practical use.

In such an engine with a variable cylinder mechanism, for example, a rocker arm having a cam follower that contacts an opening / closing cam of an intake / exhaust valve and a valve stem of the intake / exhaust valve to open / close the intake / exhaust valve. A rocker shaft that has a sub-rocker arm that directly transmits power is configured to be separable, and depending on the engine load and throttle opening, these sub-rocker arm and rocker shaft can be separated or joined to form a cylinder Mode and all cylinder mode are realized.

By the way, depending on the operating condition of the engine,
When switching from a state in which some cylinders are deactivated (hereinafter, such an operating state is referred to as cylinder deactivation mode) to a state in which all cylinders are activated (hereinafter, referred to as all cylinder mode),
Since the engine torque (or engine output) increases by the amount of cylinders that have not been operated until now, this engine torque difference (engine output difference) is transmitted to the driver as a switching shock, which may cause discomfort.

On the other hand, JP-A-56-154138
Japanese Patent Laid-Open Publication No. 2004-242242 discloses a technique in which two memories (ROMs) are provided, and when switching between the cylinder deactivation mode and the all cylinders mode, these memories are switched to change the ignition timing and the fuel injection amount. . In addition, JP-A-5-180135
The publication discloses a technique in which the shock caused by a torque change at the time of switching is reduced by retarding the ignition timing when switching between the cylinder deactivation mode and the all cylinders mode.

[0006]

However, in the above-mentioned Japanese Patent Laid-Open No. 56-154138, it is not possible to finely control both the ignition timing and the fuel injection amount, and it is not possible to greatly reduce the switching shock. There are challenges. Further, in the technique disclosed in Japanese Patent Laid-Open No. 5-180135, the switching shock is reduced only by retarding the ignition timing, and further shock reduction has been desired.

The present invention was devised in view of the above-mentioned problems, and provides an internal combustion engine with a variable cylinder mechanism, which is capable of significantly reducing the shock at the time of switching from the cylinder deactivation mode to the all cylinders mode. With the goal.

[0008]

Therefore, an internal combustion engine with a variable cylinder mechanism of the present invention according to claim 1 is an internal combustion engine having a plurality of cylinders, and a full cylinder mode in which all the plurality of cylinders are operated. And a variable cylinder mechanism capable of switching between a cylinder deactivation mode in which the operation of some of the cylinders is stopped by cutting off the intake air intake to some of the plurality of cylinders, and a load state of the internal combustion engine. Variable cylinder control means for controlling the operation of the variable cylinder mechanism so as to operate in the cylinder deactivation mode when the engine load is small and to operate in the full cylinder mode when the engine load is large, Fuel supply means for supplying fuel to each cylinder, fuel supply control means for controlling the presence or absence of fuel supply by the fuel supply means and fuel supply timing at the time of fuel supply, and ignition timing control means for controlling the ignition means are provided. The rest cylinder It is set so that the operation of a plurality of cylinders is stopped at the time of engine shutdown, and when the internal combustion engine selects the cylinder deactivation mode, the fuel supply control means is set to stop the fuel supply to the cylinders being deactivated. In an internal combustion engine with a variable cylinder mechanism, when the fuel supply control means is switched from the cylinder deactivation mode to the all cylinders mode, the fuel supply control means sequentially starts fuel supply while giving a time difference to a plurality of cylinders for which intake introduction is started. The ignition timing control means is set to retard the ignition timing with respect to the start of the fuel supply.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the internal combustion engine with a variable cylinder mechanism is such that the retard of the ignition timing at the start of fuel supply by the ignition timing control means is fuel. It is characterized in that it is started later than the start time of the fuel supply based on the time difference between the start of the supply and the start of the output of the internal combustion engine. Also,
An internal combustion engine with a variable cylinder mechanism according to a third aspect of the present invention is
In addition to the structure according to claim 1 or 2, the retard of the ignition timing at the time of starting the fuel supply by the ignition timing control means sequentially gives a fuel with a time difference when switching from the cylinder deactivation mode to the all cylinder mode. It is characterized in that it is set to be performed for all of the cylinders whose supply is started.

According to a fourth aspect of the present invention, in addition to the structure of the first or second aspect, the internal combustion engine with a variable cylinder mechanism has an ignition timing retard at the start of fuel supply by the ignition timing control means. However, it is set to be performed only for the cylinder whose fuel supply is finally started among the cylinders for which fuel supply is sequentially started while giving a time difference when switching from the cylinder deactivation mode to the all cylinders mode. It is characterized by that.

Further, in the internal combustion engine with a variable cylinder mechanism according to a fifth aspect of the present invention, in addition to the structure according to the first to fourth aspects, when the cylinder deactivation mode is switched to the full cylinder mode, It is characterized in that the fuel supply start control is set to be started with a delay of a predetermined period from the time of switching the mode.

[0012]

In the internal combustion engine with a variable cylinder mechanism according to the present invention as set forth in claim 1, the variable cylinder mechanism causes all cylinders of an internal combustion engine having a plurality of cylinders to operate, and intake to some cylinders. By shutting off the introduction, the cylinder deactivation mode in which the operation of some cylinders is stopped is switched.

The variable cylinder mechanism is controlled by the variable cylinder control means and operates in the cylinder deactivation mode when the engine load is small based on the load state of the internal combustion engine, and when the engine load is large, all cylinders are operated. Controlled to operate in mode. At this time, when the internal combustion engine selects the cylinder deactivation mode, the fuel supply control means stops the fuel supply to the cylinders that are in the cylinder deactivation, so that the fuel is used efficiently.

Further, in this internal combustion engine with a variable cylinder mechanism, when the cylinder deactivation mode is switched to the all cylinders mode, the fuel supply control means sequentially supplies fuel while giving a time difference to a plurality of cylinders for which intake introduction has been started. At the same time as the start, the ignition timing control means retards the ignition timing with respect to the start of the fuel supply, so that the switching from the cylinder deactivation mode to the all cylinders mode is made smooth.

In the internal combustion engine with a variable cylinder mechanism according to the second aspect of the present invention, the retard of the ignition timing at the start of fuel supply by the ignition timing control means is increased by the output of the internal combustion engine after the start of fuel supply. It starts later than the start time of fuel supply based on the time difference until the start. In the internal combustion engine with a variable cylinder mechanism according to the present invention as set forth in claim 3, the ignition timing control means is provided for all of the cylinders in which fuel supply is sequentially started while giving a time difference when switching from the cylinder deactivation mode to the all cylinders mode. The ignition timing is retarded at the start of fuel supply.

In the internal combustion engine with a variable cylinder mechanism according to the present invention as set forth in claim 4, the fuel is finally supplied to the last of the cylinders in which fuel supply is sequentially started while giving a time difference when switching from the cylinder deactivation mode to the all cylinders mode. Only for the cylinders whose supply is started, the ignition timing control means retards the ignition timing at the start of fuel supply. In the internal combustion engine with variable cylinder mechanism according to the fifth aspect of the present invention, when the cylinder deactivation mode is switched to the all cylinders mode, the fuel supply start control is started with a delay of a predetermined period from the mode switching time point.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 show an internal combustion engine with a variable cylinder mechanism as a first embodiment of the present invention, and FIG. 2 is a schematic block diagram showing the configuration thereof, FIG. 3 is a partial cross-sectional view showing the configuration of the main part thereof, and FIGS. 4A to 4F explain the operation thereof. FIG. 5 is a flow chart for explaining the operation.

As shown in FIG. 2, the internal combustion engine with a variable cylinder mechanism of the present embodiment is a fuel injection engine (hereinafter referred to as an engine) 1 using DOHC in-line 4-cylinder gasoline fuel. One end of an intake manifold IM capable of communicating with each cylinder is attached to a cylinder head 2 of the engine 1, and an intake manifold I
A surge tank 37 is attached to the other end of M to form an intake passage IR, and the intake passage IR further includes an intake pipe communicating with the surge tank 37, an air cleaner 38, and the like.

On the other side of the cylinder head 2, an exhaust manifold EM capable of communicating with each cylinder is attached,
An exhaust passage ER including an exhaust pipe is connected to the exhaust manifold EM. A throttle valve 40 is disposed downstream of the air cleaner 38 in the intake passage IR, and a rotary shaft 41 of the throttle valve 40 is configured to be rotated by a valve drive actuator 42 having a stepper motor. There is.

The valve drive actuator 42 is connected to an engine control unit (ECU) 32 described later,
It is configured to perform a desired rotation by a predetermined control signal. Further, the throttle valve 40 is supplied with a throttle opening signal θs corresponding to the throttle opening.
A throttle opening sensor 36 for outputting to the CU 32 is attached.

Further, a negative pressure sensor 35 for outputting a negative pressure signal Pb corresponding to the negative pressure of the intake pipe is mounted on the surge tank 37 of the intake passage IR. By the way, an intake port (not shown) of each cylinder is opened / closed by an intake valve (not shown), and an exhaust port (not shown) is also opened / closed by an exhaust valve (not shown). Each intake / exhaust valve is a well-known DOHC valve operating system. 4 is driven.

The valve train 4 includes intake / exhaust cam shafts 5 and 6 attached to the cylinder head 2 and intake / exhaust rocker shafts 7 and 8. Timing gears 9 and 10 are fixed to one ends of the intake and exhaust cam shafts 5 and 6, respectively.
Is connected to a crankshaft side (not shown) via a timing belt 11 and is driven at a rotational speed of 1/2 of the engine speed.

The intake / exhaust rocker shafts 7 and 8 are separately provided for each cylinder. The intake and exhaust valves of each cylinder are all configured to be opened and closed by a known valve operating system, one example of which is Japanese Patent Application No. 4-232232 by the present applicant.
No. 2 specification and drawings. This valve train is equipped with low / high switching means (mode switching mechanism) ML, MH having a cylinder deactivation / all cylinder switching mechanism 50 (see FIG. 3) which is a main part of the variable cylinder mechanism 48 (see FIG. 3). Has been done. As will be described in detail later, this cylinder deactivation / all cylinder switching mechanism 50
Also functions as an intake / exhaust valve stop mechanism. Mode switching mechanism M
L and MH are low solenoid valves 26 and 2 for 1 and 4 cylinders which connect the switching oil passage 23 to the hydraulic pump 25 in an intermittent manner.
It has a low solenoid valve 30 for three cylinders. In addition, the mode switching mechanisms ML and MH use the switching oil passage 24 as the hydraulic pump 25.
High solenoid valve 27 for 1 and 4 cylinders that is connected intermittently to
And a high solenoid valve 31 for two or three cylinders.
The hydraulic pump 25 is communicatively connected to the oil tank as shown.

The low-high solenoid valves 26, 30, 27, 31 are each composed of a three-way valve, and when they are turned on, they supply pressure oil for driving a hydraulic piston, which will be described later, and when they are turned off, the hydraulic actuator is connected to the drain. It is designed to connect. In this way, the solenoid valves 26, 30, 27, 31 are valves (= Oil Control Valve) that control the hydraulic pressure for driving the hydraulic piston.
Since it is ve), it is hereinafter also referred to as OCV.

These low and high solenoid valves 26, 30, 27, 3
1 is connected to the ECU 32, and is configured so that a desired switching operation is performed by a control signal from the ECU 32. Furthermore, the mode switching mechanism ML, MH
When the low electromagnetic valves 26, 30 and the high electromagnetic valves 27, 31 are both off, the intake / exhaust valve (not shown) is driven in the low speed mode. On the other hand, low and high solenoid valves 26, 30, 2
When both 7 and 31 are on, an intake / exhaust valve (not shown) is driven in the high speed mode.

Furthermore, when only the low solenoid valve 26 is turned on, the first cylinder (# 1) and the fourth cylinder (#
The cylinder deactivation mode in which the intake / exhaust valve (not shown) is idled in 4) is achieved. FIG. 3 will be referred to regarding the mode switching mechanisms ML and MH in the first cylinder (# 1) and the fourth cylinder (# 4) that can be in the cylinder deactivated state (this corresponds to the cylinder deactivated / all cylinder switching mechanism 50). However, the rocker arms 51, 51 for opening and closing the intake valve and the exhaust valve are connected to the first and fourth cylinders.
The rocker arm 51 is driven by a high speed cam (not shown), and the rocker arm 52 is driven by a low speed cam (not shown).

These rocker arms 51 and 52 can be interlocked with a T-lever 55 which can contact and drive an intake valve or an exhaust valve via hydraulic pistons 53 and 54 as a switching mechanism, respectively. There is. The hydraulic pistons 53 and 54 are connected so as to integrally operate the rocker arms 51 and 52 and the T lever 55 when the heads are fitted into the fitting holes 51A and 52A formed in the rocker arms 51 and 52, and the fitting holes 51A and 52A. When the head is removed from the locker arm 51, 52, the T lever 55 is disconnected.

The hydraulic piston 53 is a return spring 5
6 is urged to separate the head from the fitting hole 51A, and when the hydraulic pressure is supplied to the oil chamber 53A, the fitting hole 5A is inserted.
Insert the head into 1A. The hydraulic piston 54 is urged by a return spring 57 so that the head portion is fitted into the fitting hole 52A, and when the hydraulic pressure is supplied to the oil chamber 54A, the head portion is separated from the fitting hole 52A.

As a result, when hydraulic pressure is supplied to the hydraulic piston 53, the rocker arm 51 and the T lever 55 are connected,
When the hydraulic pressure of the hydraulic piston 53 is removed, the rocker arm 51
And the T lever 55 is disconnected. When the hydraulic pressure is supplied to the hydraulic piston 54, the connection between the rocker arm 52 and the T lever 55 is released, and when the hydraulic pressure of the hydraulic piston 54 is removed, the rocker arm 52 and the T lever 55 are connected.

Since the rocker arm 51 is driven by a high speed cam having a cam profile including a low speed cam, the movement of the rocker arm 51 is caused by movement of the rocker arm 51.
Includes 2 movements. Therefore, the rocker arm 51 is T
When the locker arm 52 is connected to the lever 55,
Regardless of non-connection, the T-lever 55 is driven by the high speed cam, and the intake valve and the exhaust valve are driven in the all cylinder high speed mode.

When the rocker arm 51 is disconnected from the T-lever 55, when the rocker arm 52 is connected to the T-lever 55, the T-lever 55 is driven by the low speed cam, and the intake valve and the exhaust valve are all cylinder low speed. Driven in mode.
Further, when the connection between the rocker arm 51 and the T lever 55 is released and the connection between the rocker arm 52 and the T lever 55 is also released, the T lever 55 is not driven, so that the intake valve and the exhaust valve are not opened. Will be realized.

The hydraulic pressure in the oil chamber 53A is controlled by a high electromagnetic valve (OCV for high speed) 27, and the hydraulic pressure in the oil chamber 54A is controlled by a low electromagnetic valve (OCV for low speed / cylinder deactivation) 26.
That is, when the high solenoid valve 27 is turned on (hydraulic pressure supply), the all cylinder high speed mode is set, and when both the high solenoid valve 27 and the low solenoid valve 26 are turned off (hydraulic pressure removed), the all cylinder low speed mode is set and the high solenoid valve 27 is turned off. When the low electromagnetic valve 26 is turned off (hydraulic pressure supply) as (hydraulic pressure removal), the cylinder is deactivated in the cylinder deactivation mode.

These low solenoid valve 26 and high solenoid valve 27
Are controlled by the ECU 32 together with the low electromagnetic valve 30 and the high electromagnetic valve 31, as described above. The oil chamber 53A
Is supplied with a high pressure oil pressure from an upstream side of an oil passage from an engine pump (not shown) on the engine side so that a high response hydraulic piston 53 can be driven through a high electromagnetic valve 27. It's becoming. The oil pressure in the downstream of the oil passage from the engine pump (not shown) on the engine side is supplied to the oil chamber 54A while being pressurized by the pump 60 and accumulated in the accumulator 61, and supplied through the low solenoid valve 26. The hydraulic piston 54 can be driven with a stable hydraulic pressure.

Referring again to FIG. 2, the cylinder head 2 of the engine 1 is equipped with fuel supply means FS, and the fuel supply means FS has four fuel injection means which inject fuel into intake ports (not shown) of each cylinder. The injector 28 and the fuel pressure adjusting means 29 are provided. The fuel pressure adjusting means 29 is configured to supply the fuel from the fuel supply source 44 to each injector 28 after adjusting the pressure to a constant pressure, and these injectors 28 serve as fuel control means for performing injection drive control. It is connected to the ECU 32.

The engine control by the ECU 32 will now be described. As shown in FIG.
A main part of which is constituted by a microcomputer, and the low electromagnetic valve 26, which corresponds to the operation mode set according to the operation information,
The injector drive control, the ignition timing control, and the like are configured together with the 30 and the high solenoid valves 27 and 31.

Focusing on engine operation mode control including variable cylinder control, the ECU 32 is provided with a function (hereinafter, referred to as mode control means) 70 for controlling the engine operation mode. The mode control means 70 controls the variable cylinder control. Since it also performs the above, it also functions as a variable cylinder control means. That is, as described above, the operation modes of the present engine include the cylinder deactivation mode in which the first cylinder and the fourth cylinder are deactivated by turning on / off each of the solenoid valves 26, 30, 27, 31 and the intake air of all cylinders. The all-cylinder low-speed mode in which the valves and exhaust valves are operated in the low-speed mode and the all-cylinder high-speed mode in which the intake and exhaust valves of all the cylinders are operated in the high-speed mode can be selected. Select one of them to operate the intake / exhaust valves, fuel supply status, idle speed controller (IS
C) Perform idle speed control and the like via 64 (see FIG. 3).

These modes are selected by the engine load and the engine speed (hereinafter referred to as engine speed).
It is designed to be performed according to Ne. Here, the throttle opening TPS is used as an amount corresponding to the engine load. Therefore, as shown in FIG. 3, the throttle opening sensor 36 and the engine speed sensor 33 are
It is connected to U32.

Further, in the mode control means 70, a mode determination unit (not shown) determines between the cylinder deactivation mode and the all-cylinder mode (in the case of the all-cylinder mode, the all-cylinder low-speed mode and the all-cylinder high-speed mode). The selection mode is set by the mode setting section based on the determination result by the section, and the operation of the intake valve and the exhaust valve, the fuel supply control, the idle speed control, etc. are performed according to the set mode.

The operation control of the intake valve / exhaust valve is performed while switching the mode switching mechanisms ML, MH through the low electromagnetic valves 26, 30 and the high electromagnetic valves 27, 31 described above. FIG.
In the figure, the function of the cylinder / all cylinder switching mechanism 50 in the mode switching mechanisms ML and MH is focused and shown, and the cylinder / all cylinder switching control is performed by the low solenoid valve (low speed / OCV for cylinder deactivation) 26 and Through the high solenoid valve (OCV for high speed) 27, the cylinder / all cylinder switching mechanism 5
It is performed while switching 0.

Further, as shown in FIG. 1, the ECU 32 is provided with a fuel supply control means 71 and an ignition timing control means 73, and the fuel supply means FS is controlled by the fuel supply control means 71 in the ECU 32. It is controlled according to the signal. Further, although not shown in FIGS. 2 and 3, the ignition means (spark plug) 75 provided in each cylinder of the engine 1 includes an ignition timing control means 73.
It is controlled by.

In the mode control means 70 provided in the ECU 32, each OCV is detected based on the detection information from the throttle opening sensor 36 and the engine speed sensor 33.
A control signal is set to 26, 30, 27, and 31 to actuate the hydraulic pistons 53 and 54 to operate the low / height switching means (mode switching mechanism) ML, MH and the cylinder deactivation / all cylinder switching mechanism. (Intake / exhaust valve stop mechanism) 50 is controlled.

By the way, in the internal combustion engine with a variable cylinder mechanism of the present invention, in the engine 1 thus constructed,
When the mode control means 70 determines to switch from the cylinder deactivation mode to the all cylinders mode, the fuel supply control means 71 and the ignition timing control means 73 perform the following in order to suppress the shock caused by this switching. It is designed to be controlled. The shock occurs during the switching control from the cylinder deactivation mode to the all-cylinder mode because the engine torque (engine output) sharply increases by operating the cylinder that has been deactivated.

That is, the fuel supply control means 71 starts the fuel supply sequentially while giving a time difference to each of the plurality of cylinders for which the introduction of the intake air has started, and the ignition timing control means 73 responds to the start of the fuel supply. The ignition timing is set to be retarded for all of the cylinders which are sequentially supplied with fuel while giving a time difference.

This will be explained with reference to the time charts shown in FIGS. 4A to 4F as an example. This time chart shows the control modes of the fuel supply control means 71 and the ignition timing control means 73 in the case of an in-line four-cylinder engine. It is shown. FIG.
As shown in (a), FIG. 4 (c), and FIG. 4 (d), when the control signal for switching the control mode from the cylinder deactivation mode to the all cylinders mode is set (t = 0), at the same time, the OCV 26,
Both 27 are controlled from OFF to ON, and IS
The C64 can switch the idle speed to a characteristic suitable for the all cylinder (low speed) mode.

Focusing on fuel supply control, FIG.
As shown in (b), the fuel supply control means 71 causes the fuel supply means 29 to start supplying fuel for the first one cylinder after a predetermined period T1 from when a control signal for switching to the all-cylinder mode is set (three cylinders). Fuel injection), and further, the fuel supply to the remaining one cylinder is started after a predetermined period T3 (four-cylinder fuel injection) (note that the fuel injection is performed).
Such fuel injection control is called thinning injection).

The reason why such fuel supply control is carried out is to reduce the switching shock, but the ignition timing of the ignition means 75 is changed by a predetermined gradient as shown by the broken line in FIG. 4 (e). In the conventional ignition timing control that approaches the target ignition timing of all cylinders (low speed) mode, the reduction of the engine torque fluctuation was insufficient [shown by the broken line in the graph of the engine torque characteristic of FIG. 4 (f)]. See Properties]. On the other hand, as shown in FIG. 4 (f), engine torque fluctuation occurs after a predetermined period T2 from the time of three-cylinder fuel injection, and engine torque fluctuation occurs after a predetermined period T4 from the time of four-cylinder fuel injection. Was known.

Therefore, in the present invention, the switching shock is reduced by retarding the ignition timing at the timing shown in FIG. That is, in the internal combustion engine with a variable cylinder mechanism of the present invention, the ignition timing is retarded after a predetermined period T2 from the start of the three-cylinder fuel injection, and the predetermined period T4 from the start of the four-cylinder fuel injection.
The ignition timing is also retarded later. in this way,
The fuel supply control means 71 sequentially starts fuel supply while giving a time difference to the plurality of cylinders for which intake introduction is started, and the ignition timing control means 73 causes all the cylinders of which fuel supply is sequentially started. By retarding the ignition timing, the fluctuation of the engine torque can be made to have the characteristic shown by the solid line in FIG. 4 (f), and the shock when switching from the cylinder deactivation mode to the all cylinders mode can be greatly reduced. Furthermore, this mode switching can be smoothly performed.

Since the internal combustion engine with a variable cylinder mechanism as the first embodiment of the present invention is configured as described above, the fuel injection timing and the fuel ignition timing are controlled according to the flowchart shown in FIG. 5, for example. First, as shown in FIG. 5, when there is a cylinder deactivation cancellation command (that is, a command to switch to the all cylinder mode), steps A1 and A
9. Go to step A10 at the same time, and go to step A9
The operations of the CVs 26 and 27 are controlled to switch from the cylinder deactivation mode to the all cylinders (low speed) mode. Also, step A1
At 0, the ISC is switched from the cylinder deactivation position to the low speed position.

Further, in step A1, it is judged whether or not a predetermined period T1 has elapsed with the cylinder deactivation cancellation command as a reference point. If the predetermined period T1 has not elapsed, the routine follows the NO route, and this routine is continued until the time T1 elapses. Pass through. Then, if a predetermined period T1 has elapsed from the time of issuing the cylinder deactivation cancellation command, YES
The process proceeds to step A2 through the route of No. 1, and the fuel injection is started in any one of the first and fourth cylinders that have been deactivated, and the three-cylinder fuel injection is performed.

That is, FIG. 4 (a), FIG. 4 (c), FIG.
As shown in (d), when the control mode is switched from the cylinder deactivation mode to the all cylinders mode, the OCVs 26 and 27 are immediately switched from the cylinder deactivation mode to the all cylinders (low speed) mode, and the ISC 64 is simultaneously deactivated. Although the cylinder position is switched to the all-cylinder position, the fuel injection is not injected into the three cylinders until the predetermined period T1 has elapsed for the fuel supply.

Next, the routine proceeds to step A3, where it is judged whether or not a predetermined period T2 has elapsed from the start of fuel injection into the three cylinders. Then, similar to step A1 described above, the NO route is taken until the predetermined period T2 elapses. When the predetermined time period T2 has passed, the YES route is followed by Step A.
4 and the ignition timing is retarded. In this ignition timing control, as shown in FIG. 4 (e), conventionally, the ignition timing is gradually changed with a predetermined gradient when the three-cylinder fuel injection is started. After a lapse of a predetermined period T2 from the start of the ignition, the ignition timing is retarded in consideration of the increase in the engine torque. After this retard, the ignition timing is changed with the same gradient as the conventional gradient.

As a result, as shown in FIG.
The change in engine torque at the time of cylinder fuel injection, which has changed almost stepwise in the past, becomes smooth. After that, the routine proceeds to step A5, where it is judged whether or not a predetermined period T3 has elapsed from the start of fuel injection of the three cylinders, and when it is judged that the predetermined period T3 has elapsed, the routine proceeds to the next step A6 and Start fuel injection.
The predetermined period T3 is naturally longer than the predetermined period T2 (see FIG. 4).

Then, the process proceeds to step A7, and it is determined whether or not a predetermined period T4 has elapsed since the fuel injection into all cylinders in step A6. If it is determined that the predetermined period T4 has elapsed, the process proceeds to step A8 and the ignition timing is retarded. This predetermined period T4 also takes into consideration the increase in engine torque due to the start of fuel injection in all cylinders, and according to the timing (= predetermined period T4) when the engine torque increases,
The ignition timing is retarded. After the retard, the ignition timing is changed with the same gradient as the conventional gradient, and the ignition timing is fixed at the conventional ignition timing for low speed operation [see FIG. 4 (e)].

Therefore, in the internal combustion engine with the variable cylinder mechanism according to the first embodiment of the present invention, all cylinders (low speed) are switched from the cylinder deactivation mode.
When the mode is switched to, the change characteristic of the engine torque can be made smooth, and a shock due to the increase of the engine torque hardly occurs. As a result, the driver does not feel uncomfortable, and it is possible to switch between the cylinder deactivation mode and the all cylinders (low speed) mode without impairing drivability.

Next, a second embodiment of the present invention will be described. FIGS. 6 and 7 show an internal combustion engine with a variable cylinder mechanism as a second embodiment of the present invention, and FIG. 6 explains its operation. 7 is a flow chart for explaining the operation. In the second embodiment, the specific structure of the engine is omitted, but the structure of the engine is the same as that of the first embodiment, and only the control contents are different. That is, this engine is also configured as an in-line 4-cylinder engine as shown in FIG. 2, and has an all-cylinder operation mode (all-cylinder mode) including a low-speed operation mode and a high-speed operation mode, a throttle opening TPS, and an engine rotation speed. The cylinder deactivation mode for deactivating the first and fourth cylinders can be switched based on the number Ne or the like.

In the second embodiment, the ignition timing control means 73 causes the retard of the ignition timing at the start of the fuel supply to sequentially supply fuel while giving a time difference when switching from the cylinder deactivation mode to the all cylinder mode. It is set to be performed only for the cylinder in which the fuel supply is finally started among the cylinders in which the fuel supply is started. This is shown in FIG.
Describing with reference to the time charts of (f) to (f), three-cylinder fuel injection is started after a predetermined period T1 has elapsed from the time of switching from the cylinder deactivation mode to the all cylinders mode [FIGS.
(B)]. At this time, the ignition timing by the ignition means 75 is changed with a predetermined gradient similar to that in the normal low speed mode, as shown in FIG. 6 (e). Therefore, the engine torque changes in a stepwise manner as shown in FIG. 6 (f) when the predetermined period T2 has elapsed from the time of three-cylinder fuel injection.

When the four-cylinder fuel injection is started and a predetermined period T4 has elapsed from the time of this fuel injection, the ignition timing control means 73 retards the ignition timing to smooth the engine torque as shown in FIG. 6 (f). It is designed to have various characteristics. Since the internal combustion engine with a variable cylinder mechanism as the second embodiment of the present invention is configured as described above, the fuel injection timing and the fuel ignition timing are controlled according to the flowchart shown in FIG. 7, for example.

First, as shown in FIG. 7, when there is a cylinder deactivation cancellation command (that is, a command to switch to the all cylinder mode), the process proceeds to step B1, step B7 and step B8 at the same time.
In step B7, the operations of the OCVs 26 and 27 (see FIG. 3) are controlled to switch from the cylinder deactivation mode to the all cylinders (low speed) mode. In step B8, ISC64 (see FIG.
(See) is switched from the cylinder deactivation position to the low speed position.

Further, in step B1, it is judged whether or not a predetermined period T1 has elapsed with the cylinder deactivation cancellation command as a base point, and if the predetermined period T1 has not elapsed, a NO route is taken and this routine is continued until the time T1 has elapsed. Pass through. Then, if a predetermined period T1 has elapsed from the time of issuing the cylinder deactivation cancellation command, YES
Then, the process proceeds to step B2 through the route of No. 1 to start fuel injection into any one of the first and fourth cylinders that have been deactivated, and performs three-cylinder fuel injection.

That is, FIGS. 6 (a), 6 (c) and 6
As shown in (d), when the control mode is switched from the cylinder deactivation mode to the all cylinders mode, the OCVs 26 and 27 are immediately switched from the cylinder deactivation mode to the all cylinders (low speed) mode, and the ISC 64 is simultaneously deactivated. Although the cylinder position is switched to the all-cylinder position, regarding the fuel supply main point 29, the fuel injection is not injected into the three cylinders until the predetermined period T1 elapses.

Then, after that, the routine proceeds to step B3, where it is judged whether or not a predetermined period T3 has passed since the start of fuel injection of the three cylinders, and if it is judged that the predetermined period T3 has passed,
In step B4, fuel injection into all cylinders is started. That is, as shown in FIG. 6E, unlike the first embodiment, the ignition timing is not retarded even when the fuel injection of the three cylinders is started, and the ignition timing is controlled according to the conventional low speed mode. . As a result, as shown in the engine torque characteristic diagram of FIG.
Although the engine torque fluctuates stepwise when the time elapses, the fluctuation of the engine torque at the time of fuel injection of the three cylinders does not directly cause a large shock, so that the driver is not uncomfortable.

Next, the routine proceeds from step B4 to step B5, and it is judged whether or not a predetermined period T4 has elapsed since the fuel injection into all cylinders in step B4. Here, if it is determined that the predetermined period T4 has passed, step B6
And the ignition timing is retarded. This predetermined period T4
Regarding the increase in engine torque due to the start of fuel injection in all cylinders, the ignition timing is retarded in accordance with the timing (= predetermined period T4) when the engine torque increases. Of. After the retard, the ignition timing is changed with the same gradient as the conventional gradient, and if it matches the conventional ignition timing for low speed operation, the ignition timing for low speed operation is fixed [Fig. 6].
(See (e)].

Therefore, in the internal combustion engine with the variable cylinder mechanism according to the second embodiment of the present invention, all cylinders (low speed) are switched from the cylinder deactivation mode.
When the mode is switched to, the ignition timing is retarded after the fuel is supplied to the last cylinder among the cylinders that are sequentially supplied with fuel while giving a time difference, so the engine torque change characteristics can be changed with only simple control. It can be made smooth and almost no shock is generated due to an increase in engine torque.

As a result, the driver does not feel uncomfortable, and the cylinder deactivation mode can be switched to the all cylinders (low speed) mode without impairing drivability. Next, the third embodiment of the present invention will be described. FIG. 8 is a flowchart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the third embodiment of the present invention.

The third embodiment is constructed as a V-type 6-cylinder engine, and in the cylinder deactivation mode, three cylinders of one bank are deactivated and three cylinders of the other bank are activated. ing. Also, in this V-type 6-cylinder engine, the structure of the valve operating system of each cylinder is the same as that of the above-described first embodiment, and the all-cylinder mode in which all the cylinders operate, the throttle opening TPS, and the engine. A cylinder deactivation mode in which one bank is deactivated is switched based on the rotation speed Ne and the like.

In other words, the V-type 6-cylinder engine of the third embodiment and the in-line 4-cylinder engine of the first embodiment differ only in the cylinder structure, and have the same structure except for this. In such a V-6 cylinder engine, when switching from the cylinder deactivation mode to the all cylinders mode,
The three-cylinder operation is switched to the six-cylinder operation, but in this embodiment, for the three cylinders whose operation is restarted at this time, fuel supply is sequentially started to each injector while giving a time difference by the fuel supply control means. The retarding of the ignition timing at the time of starting the fuel supply by the ignition timing control means is set to be performed for all the cylinders in which the fuel supply is sequentially started. Since the internal combustion engine with a variable cylinder mechanism as the third embodiment of the present invention is configured as described above, the fuel injection timing and the fuel ignition timing are controlled according to the flowchart shown in FIG. 8, for example.

That is, when the cylinder deactivation cancellation command is issued, the process proceeds to step C1, step C13, and step C14 at the same time. At step C13, the operation of OCV is controlled to switch from the cylinder deactivation mode to the all cylinders (low speed) mode. Further, in step C14, the ISC is switched from the cylinder deactivation position to the low speed position. Further, in step C1, it is judged whether or not a predetermined period T1 has elapsed with the cylinder deactivation cancellation command as a reference point. If the predetermined period T1 has not elapsed, the route is NO, and this routine is passed until the time T1 has elapsed.

Then, a predetermined period T1 has elapsed since the cylinder deactivation cancellation command was issued.
After a lapse of time, the process proceeds to a step C2 through a YES route to start fuel injection into any of the three cylinders that have been deactivated and perform four-cylinder fuel injection. Next, the routine proceeds to step C3, where it is judged whether or not a predetermined period T2 has elapsed from the start of the 4-cylinder fuel injection. Then, similar to step C1 described above, the NO route is taken until the predetermined period T2 elapses. After the lapse of the predetermined period T2, the process proceeds through the YES route to step C4 where the ignition timing is retarded.

After this, the process proceeds to step C5. Step C
In No. 5, it is determined whether or not a predetermined period T3 has elapsed from the start of 4-cylinder fuel injection, and if it is determined that the predetermined period T3 has elapsed, the routine proceeds to the next step C6 to start fuel injection of five cylinders. The predetermined period T3 is naturally longer than the predetermined period T2. Then, proceed to step C7,
A predetermined period T from the time of fuel injection in the five cylinders in step C6
Determine if 4 has passed. Here, the predetermined period T4
If it is determined that has passed, the process proceeds to step C8,
Ignition timing is retarded.

This predetermined period T4 also takes into consideration the increase in engine torque due to the start of fuel injection into all cylinders, and ignition is performed in accordance with the timing (predetermined period T4) when the engine torque increases. The timing is being retarded. After this, proceed to Step C9,
Here, it is determined whether or not a predetermined period T5 has elapsed from the start of fuel injection into the five cylinders, and the NO route is taken until the predetermined period T5 has elapsed. After the lapse of the predetermined period T5, the process proceeds to the step C10 through the YES route, and the 6-cylinder fuel injection (all-cylinder fuel injection) is performed.

Then, the process proceeds to step C11. In step C11, a predetermined period T6 has elapsed from the start of fuel injection into all cylinders.
It is determined whether or not it has elapsed, and if the predetermined period T6 has elapsed, the routine proceeds to the next Step C12, where the ignition timing is retarded. In the V-type 6-cylinder engine of this embodiment, when the cylinder deactivation mode is switched to the all-cylinder mode in this manner, the fuel supply control means sequentially supplies fuel to each injector for the three cylinders whose operation is restarted. And the ignition timing is retarded for all the cylinders for which the fuel supply is sequentially started. By performing fine fuel supply control and ignition timing control, the switching shock can be greatly reduced, and the V-type 6 cylinder With respect to the engine, it is possible to smoothly switch between the cylinder deactivation mode and the all cylinders mode.

Next, the fourth embodiment of the present invention will be described. FIG. 9 is a flow chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the fourth embodiment of the present invention. The fourth embodiment is configured as a V-type 6-cylinder engine that is the same as the third embodiment, and in the cylinder deactivation mode, three cylinders of one bank are deactivated and three cylinders of the other bank are activated. Is configured. Further, also in this V-type 6-cylinder engine, the structure of the valve operating system of each cylinder is the same as that of the first embodiment described above.

In other words, the V-type 6-cylinder engine of the fourth embodiment is different from the in-line 4-cylinder engine of the first embodiment only in the cylinder structure, and is otherwise the same in structure. . In the present embodiment, when the cylinder deactivation mode is switched to the all cylinders mode, the fuel supply control means sequentially starts fuel supply to each injector for the three cylinders that are restarted at this time, and the ignition timing control is performed. The retard of the ignition timing at the time of starting the fuel supply by the means is set so as to be performed only for the last cylinder to be supplied with the fuel among the cylinders with which the fuel supply is sequentially started.

Since the internal combustion engine with a variable cylinder mechanism as the fourth embodiment of the present invention is configured as described above, the fuel injection timing and the fuel ignition timing are controlled according to the flowchart shown in FIG. 9, for example. It That is, if there is a cylinder deactivation cancellation command from the ECU, step D
1, the step D9, and the step D10 are proceeded to at the same time. At the step D9, the operation of the OCV is controlled to switch from the cylinder deactivation mode to the all cylinder (low speed) mode. Further, in step D10, the ISC is switched from the cylinder deactivation position to the low speed position.

Further, in step D1, it is judged whether or not a predetermined period T1 has elapsed with the cylinder deactivation cancellation command as a reference point, and if the predetermined period T1 has not elapsed, the routine goes through the route of NO and this routine is continued until T1 time elapses. Pass through. Then, if a predetermined period T1 has elapsed from the time of issuing the cylinder deactivation cancellation command, YES
Then, the process proceeds to step D2 through the route of (4) to start fuel injection into any one of the three cylinders that have been deactivated and perform four-cylinder fuel injection.

After this, the process proceeds to step D3. Step D
In 3, it is determined whether or not a predetermined period T3 has elapsed since the start of fuel injection in the four-cylinder. If it is determined that the predetermined period T3 has elapsed, the process proceeds to the next step D4 to start fuel injection in the five cylinders. Next, the routine proceeds to step D5, where it is judged whether or not a predetermined period T5 has elapsed from the start of fuel injection into the five cylinders, and the NO route is taken until the predetermined period T5 has elapsed. When the predetermined period T5 has elapsed, the process proceeds to YES through the YES route and the 6-cylinder fuel injection (all-cylinder fuel injection) is performed.

Then, the process proceeds to step D7. In step D7, it is determined whether or not a predetermined period T6 has elapsed from the start of fuel injection in all cylinders. If it is determined that the predetermined period T6 has elapsed, the process proceeds to the next step D8 to retard the ignition timing. In the V-type 6-cylinder engine of this embodiment, when the cylinder deactivation mode is switched to the all-cylinder mode in this manner, the fuel supply control means sequentially supplies fuel to each injector for the three cylinders whose operation is restarted. The ignition timing is retarded only for the cylinder that starts fuel supply last among the cylinders that start fuel supply sequentially, and the switching shock can be reduced by a simple control, which can cause driver discomfort. Can be removed.

As a result, it becomes possible to switch from the cylinder deactivation mode to the all cylinders (low speed) mode without impairing drivability. Note that the above-mentioned first to first
In the fourth embodiment, when any of the following conditions (1) to (4) is satisfied, the ignition retard by the ignition timing control means 73 is immediately interrupted, and normal ignition timing control is performed. In the case of abrupt acceleration, the rotational speed range where the switching shock is small, the throttle opening range where the switching shock is small, and the shift is changed to a range other than the D range. All of the above conditions (1) to (2) can be detected by a known sensor provided in the vehicle, and the ECU 32 Then, based on the detection information from each sensor, when any of these conditions is met, normal ignition timing control is performed.

By the way, such control according to the present invention may be performed in combination with various other controls of the engine. Here, as a fifth embodiment, an example in which the control according to the present invention is combined with other control of the engine will be described. Although FIG. 10 is a schematic diagram showing the configuration of the control system according to the fifth embodiment, as shown in FIG.
The throttle opening TPS, the engine speed Ne, the oxygen concentration O ₂ and the information as to whether the automatic transmission is shifting or not are fetched. In addition, the ECU 32
Mode setting means 80 for setting the engine operation mode to either the cylinder deactivation mode or the all cylinder mode, and solenoid valve control means for controlling the operation of the solenoid valve (OCV) 91 according to the setting by the mode setting means 80. 81, ISC control means 82 for controlling the operation of the bypass idle speed controller (ISC) 92, fuel injection control means 83 for controlling the fuel injection means 93, and ignition means (ignition plug) 9
The ignition timing control means 84 for controlling the ignition timing of No. 4 and the power generation control means 85 for controlling the operation of the generator 95 driven by the engine 1 are provided.

In the mode setting means 80, based on the throttle opening TPS and the engine speed Ne, the throttle opening TPS1 in the higher load range than the cross point is used as the switching point, as in the first embodiment, in the cylinder deactivation mode or the all cylinders mode. Set the tube mode. However, when it is necessary to switch from the all cylinders mode to the cylinder deactivation mode by this setting, if the automatic transmission is in the gear shifting operation, it does not switch to the cylinder deactivation mode and waits until the shifting operation is completed. After the shifting operation is completed, switching to the cylinder deactivation mode is performed.

In the solenoid valve control means 81, the operation of each solenoid valve (OCV) 91 is controlled to a state according to the mode set by the mode setting means 80, and the cylinder deactivation / all cylinder switching mechanism is set to the corresponding mode state. To The ISC control means 82 controls the opening position of the valve interposed in the bypass of the ISC 92 to a cylinder deactivation position so that the idle rotation is relatively low in the cylinder deactivation mode, so that the idle rotation is higher in the all cylinder mode. The opening position of the valve installed in the bypass is controlled to the full cylinder position. In the all cylinder mode, the valve opening position may be changed between the all cylinder low speed mode and the all cylinder high speed mode.

The fuel injection control means 83 performs air-fuel ratio control in addition to the control as to whether or not fuel injection is performed.
Of course, in principle, fuel is injected into all the cylinders in the all cylinder mode, but in the cylinder deactivation mode, fuel injection is not performed in the cylinders that are in the cylinder deactivation mode. Then, at the time of switching from the cylinder deactivation mode to the all cylinders mode, fuel injection into the cylinder that newly starts intake is started after a predetermined period T1 has passed after the mode switching.
In this case as well, the fuel injection is not started at the same time for all of the cylinders for which the intake has been newly started, but the fuel injection is started while providing a time difference one by one.

For example, taking a 4-cylinder engine as an example,
The cylinders that are deactivated are, for example, two cylinders, a first cylinder and a fourth cylinder, and when switching from the deactivated cylinder mode to the all cylinders mode,
The introduction of intake air into these first cylinder and fourth cylinder is started. In the fuel injection control means 83, the first cylinder and the fourth cylinder
Even if the introduction of intake air into the cylinders is started, fuel injection is not started at the same time. For example, after a predetermined period T1 has passed after the mode switching, fuel injection into the first cylinder is first started to set the three-cylinder fuel injection state. After the lapse of the predetermined period T3, the fuel injection into the first cylinder is started to bring the fuel injection into all cylinders. Further, the periods T1 and T3 in this case are set based on the crank angle of the normal engine. The output torque of the engine is being increased stepwise by such stepwise fuel injection. As another procedure of performing the fuel injection stepwise, the three-cylinder fuel injection state may be set immediately after the mode switching, and the all-cylinder fuel injection state may be set after the subsequent period.

In the air-fuel ratio control by the fuel injection control means 83, the air-fuel ratio is stoichiometric or desired by O ₂ feedback based on the detection information of the O ₂ sensor 46 at the time of low load both in the cylinder deactivation mode and the all cylinders mode. Is controlled to be in a lean state, the O ₂ feedback is released at the time of high load, and the air-fuel ratio is controlled to be richer than that at the time of O ₂ feedback control by the open loop.

The switching load (switching throttle opening TPS) in the air-fuel ratio control mode changes depending on the engine speed, but the switching throttle opening TP in the cylinder deactivation mode.
S2 is larger than the cross point and smaller than the switching throttle opening TPS1 in the operation mode during the period. The switching throttle opening TPS3 in the all cylinder mode is naturally larger than the switching throttle opening TPS1.

The ignition timing control means 84 controls the ignition timing for suppressing an increase in the output torque of the engine that occurs in response to the start of fuel injection into a new cylinder when switching from the cylinder deactivation mode to the all cylinders mode. It is designed to perform retard control. This suppression of the ignition timing is intended to allow the output torque of the engine to increase more gradually when switching from the cylinder deactivation mode to the all cylinders mode. When fuel injection is started from the cylinder deactivated state to the activated state, the output torque rapidly increases stepwise in response to this,
At this time, if the ignition timing is temporarily retarded, the output torque is suppressed from increasing, and gradually increases to reduce the mode switching shock. The retard of the ignition timing is slightly delayed from the start of fuel injection to the cylinder that has started the operation (waiting only for the periods T2 and T4), and the timing at which the output torque actually increases after the start of fuel injection is estimated. To be executed.

The power generation control means 85 performs control (power generation cut control) to stop power generation by the power generator 95 when the engine is rotating at high speed in the cylinder deactivation mode. Of course, under conditions other than that, the power generation cut control is canceled and the generator 9
Power generation by 5 is executed. As a result, the switching shock, which is a problem when switching from the cylinder deactivation mode to the all cylinders mode when the engine is rotating at a high speed, is intended to be suppressed.

The control system of the internal combustion engine with a variable cylinder mechanism according to the fifth embodiment of the present invention is constructed as described above.
For example, each control is performed as shown in FIG. That is, as shown in FIG. 11, in step S10, the throttle opening TPS, the engine speed Ne, the oxygen concentration O ₂ and the information as to whether or not the automatic transmission is shifting are read, and the routine proceeds to step S12. First, it is determined from the flag information in the ECU 32 whether or not the current mode is the all cylinder mode. That is, if the cylinder deactivation / all cylinders flag F is 1, it is the current all cylinders mode, and if the flag F is 0, it is the current cylinders deactivation mode.

In the all cylinder mode at present, the routine proceeds to step S14, where the throttle opening TPS is set to the switching point value TPS1.
And whether to switch to the cylinder deactivation mode or not. If TPS is less than TPS1, it is necessary to switch to the cylinder deactivation mode, but at this time, the routine proceeds to step S16, where it is determined whether or not the automatic transmission (AT) is in a switching operation. If the automatic transmission is in the switching operation, the process proceeds to step S16, waits until the switching operation is completed, and switches to the cylinder deactivation mode. As a result, the switching to the cylinder deactivation mode is not performed during the switching operation of the transmission. Accordingly, if the all cylinder mode is switched to the cylinder deactivation mode during the switching operation of the transmission, a large switching shock will occur, but this can be avoided.

Next, in step S20, the operating state in the cylinder deactivation mode is set. When the cylinder deactivation mode is set, the map for cylinder deactivation is selected as the O ₂ feedback zone determination map (step S22) and step S3.
The cylinder deactivation air-fuel ratio control by 0 to S36 is executed. Also,
The solenoid valve (OCV) 81 is set to the cylinder deactivation mode (step S2
4), the ISC 92 is controlled to the cylinder deactivation position, and various control targets to be linked to the cylinder deactivation are controlled to the cylinder deactivation side (step S26). Further, in the cylinder deactivation mode, in the high engine speed region where the engine speed Ne is equal to or higher than the predetermined engine speed Ne ₁ , the process proceeds from the determination of step S28 to step S40 to perform the power generation cut control. The engine speed Ne is the predetermined speed N
If it is not in the high rotation region of e ₁ or more, the process proceeds from step S28 to step S42 to cancel the power generation cut control and execute power generation.

[0091] air-fuel ratio control for cylinder deactivation in step S30~S38 from first, at step S30, by using the O ₂ feedback zone determination map for cylinder deactivation, the detected engine speed Ne and the throttle opening TPS, O ₂ Determine if it is in the feedback zone. Throttle opening TP
If S is less than the switching throttle opening TPS2 corresponding to the engine speed Ne at this time, it is the O ₂ feedback zone, and the process proceeds to step S32 to carry out the O ₂ feedback control. If the detected throttle opening TPS is equal to or greater than the switching throttle opening TPS2, it means the enrichment zone, the process proceeds to step S34, the O ₂ feedback control is canceled, and the enrichment control is performed in step S36. Thereafter, the process proceeds to step S38, and the cylinder deactivation / all cylinder flag F is set to 0.
(Cylinder suspension mode).

On the other hand, if the flag F is 0, the cylinder is currently in the cylinder deactivation mode, and the routine proceeds from step S12 to step S44, and the throttle opening TPS is compared with the switching point value TPS1 to determine whether or not to switch to the all cylinders mode. To do. TP
If S is TPS1 or more, it is necessary to switch to the all cylinder mode.
At this time, the process proceeds to step S46 to set the operating state in the all-cylinder mode.

When the all cylinder mode is set, the solenoid valve (OC
V) 81 is set to full cylinder mode (step S48), ISC
Various control targets that should be linked to all cylinders, such as controlling 92 to all cylinder positions, are controlled to all cylinders (step S50). Further, the process proceeds to step S52 to cancel the power generation cut control and execute power generation. Immediately after switching to the all cylinders mode, the flag F is 0, the process proceeds to step S56 in the determination of step S54, and after waiting for a predetermined period T1,
In step S58, the map for all cylinders is selected as the O ₂ feedback zone determination map, fuel injection is started only in one of the cylinders that have been switched from the cylinder deactivated operation to the three-cylinder fuel injection state. Yes (step S60). Further, after waiting for a predetermined period T2 in step S62, the ignition timing is retarded (step S64). Then, after the three-cylinder fuel injection state is set in step S66, the fuel injection is started for the predetermined period T3, and the fuel injection to the remaining cylinders is started to set the all-cylinder fuel injection state (step S6).
8). Furthermore, after waiting for a predetermined period T4 in step S70, the ignition timing is retarded again (step S70).
72).

In this way, when the all-cylinder fuel injection state is reached, the all-cylinder air-fuel ratio control in steps S74 to S80 is executed. That is, first, in step S74, O for all cylinders
_{2 Based} on the detected engine speed Ne and throttle opening TPS using the feedback zone determination map,
₂ Determine if it is in the feedback zone. If the throttle opening TPS is less than the switching throttle opening TPS2 corresponding to the engine speed Ne at this time, it is in the O ₂ feedback zone, and the routine proceeds to step S76 to execute the O ₂ feedback control. If the detected throttle opening TPS is equal to or greater than the switching throttle opening TPS2, it means the enrichment zone, the process proceeds to step S78, the O ₂ feedback control is released, and the enrichment control is performed in step S80. After that, the process proceeds to step S82, and the cylinder deactivation all cylinder flag F is set to 1 (all cylinder mode).

Although the four-cylinder engine has been described in each of the above-described embodiments, the engine (internal combustion engine) to which the present invention is applicable is not limited to the number of cylinders, the in-line type or the V-type. .

[0096]

As described above in detail, according to the internal combustion engine with a variable cylinder mechanism of the present invention as defined in claim 1, the internal combustion engine has a plurality of cylinders, and all the plurality of cylinders are operated. A variable cylinder mechanism capable of switching between a cylinder mode and a cylinder deactivation mode in which operation of some of the cylinders is stopped by cutting off intake air to some of the plurality of cylinders, and a load of the internal combustion engine. Variable cylinder control means for controlling the operation of the variable cylinder mechanism so as to operate in the cylinder deactivation mode when the engine load is small based on the state and to operate in the full cylinder mode when the engine load is large. A fuel supply means for supplying fuel to each cylinder, a fuel supply control means for controlling the presence / absence of fuel supply by the fuel supply means and a fuel supply timing at the time of fuel supply, and an ignition timing control means for controlling the ignition means And the rest In this mode, the operation of a plurality of cylinders is set to stop, and when the internal combustion engine selects the cylinder deactivation mode, the fuel supply control means stops the fuel supply to the cylinders in the cylinder deactivation. In an internal combustion engine with a cylinder mechanism, when the fuel supply control means is switched from the cylinder deactivation mode to the all cylinders mode, the fuel supply control means sequentially starts fuel supply while giving a time difference to a plurality of cylinders for which intake introduction has been started. As the ignition timing control means is set to retard the ignition timing with respect to the start of the fuel supply, the output increase of the internal combustion engine is smoothed when switching from the cylinder deactivation mode to the all cylinders mode. Therefore, the shock due to the output fluctuation of the internal combustion engine can be significantly reduced. Further, since it is not necessary to newly provide a component, there is an advantage that such a shock reducing effect can be realized at low cost.

According to the internal combustion engine with a variable cylinder mechanism of the present invention as defined in claim 2, in addition to the structure of claim 1, the retard of the ignition timing at the start of fuel supply by the ignition timing control means is increased. When switching from the cylinder deactivation mode to the all-cylinder mode, the configuration is started after the start of the fuel supply based on the time difference from the start of the fuel supply until the output of the internal combustion engine starts to increase. It is possible to greatly reduce the switching shock caused by the increase in the output of the internal combustion engine. There is also an advantage that such a shock reducing effect can be realized at low cost.

According to the internal combustion engine with a variable cylinder mechanism of the present invention as defined in claim 3, in addition to the structure of claim 1 or 2, the ignition timing at the time of starting the fuel supply by the ignition timing control means. The retard is set so as to be performed for all of the cylinders in which fuel supply is sequentially started while giving a time difference at the time of switching from the cylinder deactivation mode to the all cylinder mode, thereby increasing the output of the internal combustion engine. It can be made smooth, and the switching shock can be greatly reduced at low cost.

According to a fourth aspect of the present invention, in addition to the structure of the first or second aspect, the internal combustion engine with a variable cylinder mechanism has an ignition timing retard at the start of fuel supply by the ignition timing control means. However, it is said that it is set to be performed only for the cylinder whose fuel supply is finally started among the cylinders which are sequentially supplied with fuel while giving a time difference when switching from the cylinder deactivation mode to the all cylinders mode. With the configuration, the switching shock can be reduced only by simple control, and the switching from the cylinder deactivation mode to the all cylinders mode can be executed without making the driver feel uncomfortable.
There is also an advantage that such a shock reducing effect can be realized at low cost.

Further, the internal combustion engine with a variable cylinder mechanism according to a fifth aspect of the present invention, in addition to the constitutions according to the first to fourth aspects, has the following features when the deactivated cylinder mode is switched to the all-cylinder mode. With the configuration in which the start control of the fuel supply is started with a delay of a predetermined period from the time of switching the mode, the output increase of the internal combustion engine can be smoothed and the switching shock can be reduced at low cost. There is an advantage that you can.

[Brief description of drawings]

FIG. 1 is a control block diagram focusing on control contents in an internal combustion engine with a variable cylinder mechanism as a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of an internal combustion engine with a variable cylinder mechanism as a first embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing a configuration of a main part of an internal combustion engine with a variable cylinder mechanism as a first embodiment of the present invention.

FIG. 4 is a time chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the first embodiment of the present invention.

FIG. 5 is a flow chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the first embodiment of the present invention.

FIG. 6 is a time chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the second embodiment of the present invention.

FIG. 7 is a flow chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the second embodiment of the present invention.

FIG. 8 is a flow chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the third embodiment of the present invention.

FIG. 9 is a flow chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the fourth embodiment of the present invention.

FIG. 10 is a schematic block diagram showing a configuration of a control system in an internal combustion engine with a variable cylinder mechanism as a fifth embodiment of the present invention.

FIG. 11 is a flow chart for explaining the operation of the internal combustion engine with a variable cylinder mechanism as the fifth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 engine (internal combustion engine with variable cylinder mechanism) 2 cylinder head 4 DOHC type valve system 5,6 intake / exhaust cam shaft 7,8 intake / exhaust rocker shaft 9,10 timing gear 11 timing belt 23 switching oil passage 23 hydraulic pump 26 low electromagnetic valve (OCV for low speed and cylinder deactivation) 27 High solenoid valve (OCV for high speed) 28 Injector 28A Injector driver 29 Fuel pressure adjusting means 30 Low solenoid valve (OCV for low speed) 31 High solenoid valve (OCV for high speed) 32 Electronic control unit 35 Negative Pressure sensor 36 Throttle opening sensor 37 Surge tank 38 Air cleaner 40 Throttle valve 41 Throttle valve 40 rotation shaft 42 Valve drive actuator 44 Fuel supply source 46 O ₂ sensor 48 Variable cylinder mechanism 50 Cylinder / all cylinder switching mechanism (intake / exhaust valve) Stopping mechanism) 51,52 Rocker arm 51 , 52A Fitting hole 53, 54 Hydraulic piston 53A, 54A Oil chamber 55 T lever 56, 57 Return spring 60 Hydraulic pump 61 Accumulator 64 Idle speed controller 70 Mode control means (variable cylinder control means) EM Exhaust manifold ER Exhaust passage FS Fuel supply Means IM intake manifold IR Intake passage ML, MH Low / high switching means (mode switching mechanism) 73 Ignition timing control means 71 Fuel supply control means 75 Ignition means (ignition plug) 80 Mode setting means 81 Electromagnetic valve control means 82 ISC control means 83 Fuel injection control means 84 Ignition timing control means 85 Control means 91 Electromagnetic valve (OCV) 92 Bypass type idle speed controller (IS
C) 93 fuel injection means 94 ignition means (spark plug) 95 generator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02D 43/00 301 BHZ F02P 5/15 (72) Inventor Katsunori Ueda Shibago, Minato-ku, Tokyo 33-8, Mitsubishi Motors Co., Ltd. (72) Inventor, Etsuo Shimoda 5-33, Shiba, Minato-ku, Tokyo Mitsubishi Motors, Ltd. (72) Inventor, Hideo Nakai 5-chome, Shiba, Minato-ku, Tokyo 33-8 No. Mitsubishi Motors Corporation

Claims (5)

[Claims] 1. An internal combustion engine having a plurality of cylinders, wherein the all-cylinder mode in which all of the plurality of cylinders are operated and the introduction of intake air to a part of the plurality of cylinders is cut off. A variable cylinder mechanism capable of switching between a cylinder deactivation mode for stopping the operation of the cylinders of the other section, and a case where the engine load is small when the engine load is small based on the load state of the internal combustion engine and the engine load is large The variable cylinder control means for controlling the operation of the variable cylinder mechanism so as to operate in the all cylinder mode, the fuel supply means for supplying fuel to each cylinder, the presence or absence of fuel supply by the fuel supply means, and The fuel supply control means controls fuel supply timing during fuel supply, and the ignition timing control means controls ignition means, and is set to stop the operation of the plurality of cylinders in the cylinder deactivation mode. Internal combustion machine In the internal combustion engine with a variable cylinder mechanism, which is set to stop the fuel supply to the cylinder that is in the cylinder deactivation mode when the cylinder deactivation mode is selected, the fuel supply control means changes the mode from the cylinder deactivation mode to When switching to the all cylinder mode,
The fuel supply is sequentially started while giving a time difference to the plurality of cylinders for which the introduction of intake air is started, and the ignition timing control means is set to retard the ignition timing with respect to the start of the fuel supply. An internal combustion engine with a variable cylinder mechanism, characterized in that 2. The retard of the ignition timing at the time of starting the fuel supply by the ignition timing control means is based on the time difference from the start of the fuel supply until the output of the internal combustion engine starts to increase from the start time of the fuel supply. The internal combustion engine with a variable cylinder mechanism according to claim 1, wherein the internal combustion engine is started after a delay. 3. The retardation of the ignition timing at the time of starting the fuel supply by the ignition timing control means gives a time difference at the time of switching from the cylinder deactivation mode to the all cylinder mode of the cylinders in which the fuel supply is sequentially started. The internal combustion engine with a variable cylinder mechanism according to claim 1 or 2, wherein the internal combustion engine is set to be performed for all. 4. The retardation of the ignition timing at the time of starting the fuel supply by the ignition timing control means gives a time difference at the time of switching from the cylinder deactivation mode to the all cylinders mode, and the fuel supply of the cylinders is sequentially started. The internal combustion engine with a variable cylinder mechanism according to claim 1 or 2, characterized in that it is set so as to be performed only for the cylinder whose fuel supply is finally started. 5. When the cylinder deactivation mode is switched to the all cylinders mode, the fuel supply start control is set to be started with a delay of a predetermined period from the mode switching time. An internal combustion engine with a variable cylinder mechanism according to any one of claims 1 to 4.