JP2940413B2 - Internal combustion engine with variable cylinder mechanism - Google Patents

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 stop mode in which operation of some cylinders is stopped. .

[0002]

2. Description of the Related Art In recent years, in internal combustion engines (engines) used in vehicles such as automobiles, during low load operation, some of the plurality of cylinders of the engine are deactivated to reduce fuel consumption, and to reduce fuel consumption. During load operation, an engine with a so-called variable cylinder mechanism (or an engine with a cylinder stop mechanism) that operates all cylinders to improve drivability
Has been put to practical use.

In such an engine with a variable cylinder mechanism, for example, a rocker arm provided with a cam follower that comes into contact with an opening / closing cam of an intake / exhaust valve, and an opening / closing driving force applied to the intake / exhaust valve by coming into contact with the valve stem of the intake / exhaust valve. And a rocker shaft with a sub rocker arm that directly transmits power, and the cylinder is closed by separating or connecting these sub rocker arms and the rocker shaft according to the engine load and throttle opening. Mode and all-cylinder mode.

By the way, according to the operating state of the engine,
When switching from a state in which some cylinders are stopped (hereinafter, such an operation state is referred to as a cylinder-stop mode) to a state in which all cylinders are operated (hereinafter, referred to as an all-cylinder mode),
Since the engine torque (or engine output) is increased by the amount of the cylinder that has not been operated so far, the engine torque difference (engine output difference) is transmitted to the driver as a switching shock, which may cause discomfort.

On the other hand, Japanese Patent Application Laid-Open No. 56-154138 discloses
Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a technique having two memories (ROM), and switching between these memories when switching between the cylinder-stop mode and the all-cylinder mode to change the ignition timing and the fuel injection amount. . Also, Japanese Patent Application Laid-Open No. 5-180135
Japanese Patent Application Laid-Open Publication No. H11-163,086 discloses a technique in which the ignition timing is retarded at the time of switching between the cylinder-stop mode and the all-cylinder mode to reduce a shock caused by a torque change at the time of switching.

[0006]

However, the above-mentioned Japanese Patent Application Laid-Open No. 56-154138 does not precisely control both the ignition timing and the fuel injection amount, and does not significantly reduce the switching shock. There are issues. Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 5-180135, the switching shock is reduced only by retarding the ignition timing, and further reduction of the shock has been desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides an internal combustion engine with a variable cylinder mechanism which can significantly reduce a shock when switching from the cylinder-stop mode to the all-cylinder mode. With the goal.

[0008]

Therefore, an internal combustion engine with a variable cylinder mechanism according to the present invention is an internal combustion engine having a plurality of cylinders, wherein all the cylinders are operated. A variable cylinder mechanism capable of switching between a cylinder stop mode in which the operation of some of the plurality of cylinders is stopped by interrupting the introduction of intake air 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 to operate in the cylinder-stop mode when the engine load is small and to operate in the full-cylinder mode when the engine load is large, Fuel supply means capable of supplying fuel for 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 ignition means. In addition, the rest cylinder The operation of the plurality of cylinders is set to be stopped at the time of the engine mode, and the internal combustion engine is set so as to stop the fuel supply to the cylinder during the cylinder stop through the fuel supply control means when the cylinder stop mode is selected. In an internal combustion engine with a variable cylinder mechanism, when the fuel supply control means is switched from the cylinder-stop mode to the all-cylinder 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. And the ignition timing control means makes the output of the internal combustion engine respond to the start of the fuel supply.
Start of the fuel supply based on the time difference until it starts to increase
The ignition timing is set to be retarded later than the time point .

[0009] The variable-cylinder mechanism with an internal combustion engine of the present invention according to claim 2, in addition to the first aspect, wherein, the retarded ignition timing at the start of the fuel supply by the ignition timing control means, said When switching from the cylinder-stop mode to the all-cylinder mode
Cylinders that are started to supply fuel sequentially while giving a time difference
It is characterized in that it is set to be performed for all .

Further, in addition to the above claim 1 Symbol placement,
The retardation of the ignition timing at the start of fuel supply by the ignition timing control means gives a time difference when switching from the cylinder-stop mode to the all-cylinder mode. May be set to be performed only for the cylinders that are being started (aspect 1).

Further, the first and second aspects and the first aspect
In addition to the configuration described in any one of the above, when the mode is switched from the cylinder-stop mode to the all-cylinder mode, the fuel supply start control is started so as to be delayed by a predetermined period from the mode switching time. (Aspect 2).

[0012]

In the internal combustion engine with a variable cylinder mechanism according to the first aspect of the present invention, the variable cylinder mechanism operates all cylinders of an internal combustion engine having a plurality of cylinders, and intake air to some of the cylinders. By switching off the introduction, the mode is switched to the cylinder-stop mode in which the operation of some of the cylinders is stopped.

The above-described variable cylinder mechanism is controlled by a variable cylinder control means, and based on the load condition of the internal combustion engine, operates in a cylinder stop mode when the engine load is small, and operates in all cylinders when the engine load is large. It is controlled to operate in the mode. At this time, when the internal combustion engine selects the cylinder-stop mode, the fuel supply to the cylinders in the cylinder-stop state is stopped via the fuel supply control means, and the fuel is used efficiently.

In the internal combustion engine with a variable cylinder mechanism, when the mode is switched from the cylinder-stop mode to the all-cylinder mode, the fuel supply control means sequentially supplies fuel while giving a time difference to the plurality of cylinders for which the introduction of intake air has been started. The time difference between the start of the fuel supply and the start of the increase in the output of the internal combustion engine with respect to the start of the fuel supply.
, The ignition timing is retarded later than the start of fuel supply, thereby making the switching from the cylinder-stop mode to the all-cylinder mode smooth.

In the internal combustion engine with the variable cylinder mechanism according to the second aspect of the present invention, the mode is switched from the cylinder-stop mode to the all-cylinder mode.
Fuel supply is started sequentially while giving a time difference at the time of replacement
Fuel supply by ignition timing control means for all cylinders
The ignition timing at the start of the ignition is retarded.

In the first aspect , the ignition timing is set only for the cylinder for which the fuel supply is started last among the cylinders for which the fuel supply is started sequentially while giving a time difference when switching from the cylinder-stop mode to the all-cylinder mode. The ignition timing at the start of fuel supply is retarded by the control means. In the above-described aspect 2 , when the mode is switched from the cylinder-stop mode to the all-cylinder mode,
The fuel supply start control is started with a delay of a predetermined period from the mode switching time.

[0017]

1 to 5 show an internal combustion engine with a variable cylinder mechanism according to a first embodiment of the present invention, and FIG. , FIG. 2 is a schematic diagram schematically showing the configuration, FIG. 3 is a partial cross-sectional view showing the main configuration, and FIGS. 4 (a) to (f) all explain the operation. FIG. 5 is a flowchart for explaining the operation.

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

An exhaust manifold EM that can communicate with each cylinder is attached to the other side of the cylinder head 2.
An exhaust passage ER including an exhaust pipe and the like 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 rotation shaft 41 of the throttle valve 40 is configured to be rotated by a valve drive actuator 42 having a stepper motor. I have.

The valve drive actuator 42 is connected to an engine control unit (ECU) 32 described later,
A desired rotation is performed by a predetermined control signal. Further, the throttle valve 40 supplies a throttle opening signal θs corresponding to the throttle opening to E
A throttle opening sensor 36 that outputs 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 in the intake path IR. An intake port (not shown) of each cylinder is opened and closed by an intake valve (not shown), and an exhaust port (not shown) is opened and closed by an exhaust valve (not shown). Each intake / exhaust valve is a well-known DOHC type valve train. 4.

The valve train 4 has suction and discharge cam shafts 5 and 6 mounted on the cylinder head 2 and suction and discharge rocker shafts 7 and 8. Timing gears 9 and 10 are fixed to one ends of the intake and discharge cam shafts 5 and 6, respectively.
Is connected to a crankshaft (not shown) via a timing belt 11, and is configured to be driven at half the engine speed.

The intake / discharge rocker shafts 7, 8 are provided separately for each cylinder. All the intake and exhaust valves of each cylinder are configured to be opened and closed by a well-known valve train. One example is disclosed in Japanese Patent Application No. Hei.
No. 2 is disclosed in the specification and the drawings. This valve train is equipped with low-high switching means (mode switching mechanisms) ML and MH having a cylinder-stop / all-cylinder switching mechanism 50 (see FIG. 3) which is a main part of the variable cylinder mechanism 48 (see FIG. 3). Have been. As will be described later in detail, the cylinder-stop / all-cylinder switching mechanism 50
Also serves 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 that connect the switching oil passage 23 to the hydraulic pump 25 in an intermittent manner.
A low solenoid valve 30 for three cylinders is provided. The mode switching mechanisms ML and MH connect the switching oil passage 24 to the hydraulic pump 25.
High solenoid valve 27 for 1 and 4 cylinders connected intermittently to
And a high solenoid valve 31 for two or three cylinders.
The hydraulic pump 25 is connected to an oil tank as shown in the figure.

Each of the low and high solenoid valves 26, 30, 27, and 31 is constituted by a three-way valve, and supplies hydraulic oil for driving a hydraulic piston, which will be described later, when turned on, and connects the hydraulic actuator to the drain when turned off. It is supposed to connect. As described above, the solenoid valves 26, 30, 27, and 31 are valves that control the hydraulic pressure for driving the hydraulic piston (= Oil Control Valve).
ve), henceforth 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 to perform a desired switching operation in accordance with a control signal from the ECU 32. Further, the mode switching mechanisms ML, MH
When the low solenoid valves 26 and 30 and the high solenoid valves 27 and 31 are both off, the intake and exhaust valves (not shown) are 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 a high-speed mode.

Further, when only the low solenoid valve 26 is ON, the first cylinder (# 1) and the fourth cylinder (#
The cylinder stop mode in which an intake / exhaust valve (not shown) is operated idle in 4) is achieved. The mode switching mechanisms ML and MH in the first cylinder (# 1) and the fourth cylinder (# 4) which can be in the cylinder-stop state (this corresponds to the cylinder-stop / all-cylinder switching mechanism 50) will be described with reference to FIG. To be more specific, these first and fourth cylinders have two rocker arms 51, 52 for opening and closing the intake and exhaust valves.
A 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).

The rocker arms 51 and 52 can be linked to a T lever 55 which can contact and drive an intake valve or an exhaust valve via hydraulic pistons 53 and 54 as switching mechanisms, respectively. I have. The hydraulic pistons 53 and 54 connect the rocker arms 51 and 52 and the T-lever 55 so as to operate integrally 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 released from the, the connection between the rocker arms 51 and 52 and the T lever 55 is released.

The hydraulic piston 53 has a return spring 5
6, the head is released from the fitting hole 51A, and when the oil pressure is supplied to the oil chamber 53A, the fitting hole 5A is pressed.
Insert the head into 1A. The hydraulic piston 54 is urged by a return spring 57 so as to fit its head into the fitting hole 52A. When hydraulic pressure is supplied to the oil chamber 54A, the head is disengaged from the fitting hole 52A.

Thus, 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 is released.
Is disconnected from the T lever 55. When 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 controlled by the rocker arm 5.
2 movements. Therefore, the rocker arm 51
When the rocker 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, the rocker arm 52 is connected to 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. Driven in mode.
Further, when the connection of the rocker arm 51 to the T lever 55 is released and the connection of the rocker arm 52 to the T lever 55 is released, the T lever 55 is not driven, so that the intake valve and the exhaust valve are not opened. Is realized.

The oil pressure in the oil chamber 53A is controlled by a high solenoid valve (high-speed OCV) 27, and the oil pressure in the oil chamber 54A is controlled by a low solenoid valve (low-speed, cylinder-stop OCV) 26.
That is, when the high solenoid valve 27 is turned on (oil pressure supply), the all cylinder high speed mode is set. When both the high solenoid valve 27 and the low solenoid valve 26 are turned off (oil pressure is removed), the all cylinder low speed mode is set and the high solenoid valve 27 is turned off. When the low solenoid valve 26 is turned off (oil pressure supply) as (oil pressure removal), the cylinder enters a cylinder-stop mode in which the cylinder is closed.

The low solenoid valve 26 and the high solenoid valve 27
Is controlled by the ECU 32 together with the low solenoid valve 30 and the high solenoid 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 as to drive a hydraulic piston 53 requiring a high response through the high solenoid valve 27. It is becoming. The oil chamber 54 </ b> A is supplied with the reduced hydraulic pressure on the downstream side of the oil passage from an engine pump (not shown) on the engine side while being pressurized by the pump 60 and accumulated by the accumulator 61. The hydraulic piston 54 can be driven with stable hydraulic pressure.

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

Here, the engine control by the ECU 32 will be described. As shown in FIG.
The main part is constituted by a microcomputer, and the low solenoid valve 26,
The control unit 30 and the high solenoid valves 27 and 31 are configured to perform injector drive control, ignition timing control, and the like.

Focusing on the engine operation mode control including the 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. Therefore, it also functions as variable cylinder control means. That is, as described above, the operation mode of the present engine includes a cylinder-stop mode in which the first and fourth cylinders are closed by turning on / off each of the solenoid valves 26, 30, 27, and 31, and an intake mode for all cylinders. It is possible to select a low-speed mode for all cylinders in which the valves and exhaust valves are operated in a low-speed mode, and a high-speed mode for all cylinders in which the intake valves and exhaust valves of all the cylinders are operated in a high-speed mode. Of the intake and exhaust valves, fuel supply status, idle speed controller (IS
C) Idle speed control and the like are performed via 64 (see FIG. 3).

The selection of these modes depends on the engine load and the engine speed (hereinafter referred to as engine speed).
Ne is performed according to Ne. Here, the throttle opening TPS is used as the amount corresponding to the engine load. Therefore, as shown in FIG. 3, the throttle opening sensor 36 and the engine speed sensor 33
Connected to U32.

In the mode control means 70, a mode judging unit (not shown) judges a cylinder-stop mode and an all-cylinder mode (in the case of the all-cylinder mode, furthermore, an all-cylinder low-speed mode and an all-cylinder high-speed mode). The selection mode is set by the mode setting unit based on the determination result by the unit, and the operation of the intake valve and the exhaust valve, the fuel supply control, the idle speed control, and the like are performed according to the set mode.

The operation control of the intake valve and the exhaust valve is performed while switching the mode switching mechanisms ML and MH through the low solenoid valves 26 and 30 and the high solenoid valves 27 and 31 described above. FIG.
In the figures, the functions of the cylinder-stop / all-cylinder switching mechanism 50 in the mode switching mechanisms ML and MH are shown, and the cylinder-stop / all-cylinder switching control is performed by the low solenoid valve (low-speed / cylinder OCV) 26 and Cylinder closed / all cylinder switching mechanism 5 through high solenoid valve (OCV for high speed) 27
This is performed while switching 0.

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

The mode control means 70 provided in the ECU 32 controls each OCV based on information detected from the throttle opening sensor 36 and the engine speed sensor 33.
Control signals are set to 26, 30, 27, and 31, thereby operating the hydraulic pistons 53 and 54 to switch the low / high switching means (mode switching mechanisms) ML and MH and the cylinder-stop / all-cylinder switching mechanism. (Intake / exhaust valve stop mechanism) 50 is controlled.

By the way, in the internal combustion engine with the variable cylinder mechanism of the present invention, in the engine 1 thus configured,
When it is determined by the mode control means 70 to switch from the cylinder-stop mode to the all-cylinder mode, the fuel supply control means 71 and the ignition timing control means 73 perform the following in order to suppress the occurrence of a shock caused by this switching. Control is performed. The reason why a shock occurs during the switching control from the cylinder-stop mode to the all-cylinder mode is that the engine torque (engine output) sharply increases by activating the cylinder that has been inactive until now.

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

This will be described by taking the time charts shown in FIGS. 4A to 4F as an example. This time chart shows the control mode 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), (c) and (d) of FIG. 4, when a control signal for switching the control mode from the cylinder-stop mode to the all-cylinder mode is set (t = 0), the OCV 26,
27 are controlled from off to on, and IS
The C64 switches 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 cylinder after a predetermined period T1 after the control signal for switching to the all-cylinder mode is set (three cylinders). (Fuel injection), and is controlled so that the supply of the remaining one cylinder of fuel is started (four-cylinder fuel injection) after a predetermined period of time T3.
Such fuel injection control is called thinning injection).

The fuel supply control is performed to reduce the switching shock. The ignition timing of the ignition means 75 is changed at a predetermined gradient as shown by a broken line in FIG. In the conventional ignition timing control that approaches the target ignition timing in the all-cylinder (low speed) mode, the reduction of the engine torque fluctuation was insufficient [shown by a broken line in the engine torque characteristic graph of FIG. See properties). On the other hand, as shown in FIG. 4 (f), it has been conventionally known that an engine torque fluctuation occurs after a predetermined period T2 from the three-cylinder fuel injection and an engine torque fluctuation occurs a predetermined period T4 after the 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 the variable cylinder mechanism of the present invention, the ignition timing is retarded after the 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.
Later, the ignition timing is retarded. in this way,
The fuel supply control means 71 sequentially starts the fuel supply while giving a time difference to the plurality of cylinders for which the introduction of the intake air has been started. The ignition timing control means 73 controls all the cylinders for which the fuel supply is sequentially started. By retarding the ignition timing, the fluctuation of the engine torque can be made to have the characteristics shown by the solid line in FIG. 4 (f), and the shock when switching from the cylinder-stop mode to the all-cylinder mode can be greatly reduced. In addition, the mode can be smoothly switched.

Since the internal combustion engine with the variable cylinder mechanism according to 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, for example, a flowchart shown in FIG. First, as shown in FIG. 5, when there is a cylinder deactivation release instruction (that is, an instruction to switch to the all cylinders mode), step A1, step A
9. The process proceeds to step A10 at the same time.
The operation of the CVs 26 and 27 is controlled to switch from the cylinder-stop mode to the all-cylinder (low-speed) mode. Step A1
At 0, the ISC is switched from the cylinder rest position to the low speed position.

In step A1, it is determined whether or not a predetermined period T1 has elapsed from the time of the cylinder deactivation release command. If the predetermined period T1 has not elapsed, the routine passes through the NO route until the time T1 has elapsed. Pass through. If a predetermined period T1 has elapsed since the cylinder deactivation release instruction, YES
Then, the process proceeds to step A2, in which fuel injection is started in any one of the first and fourth cylinders that have been closed to perform three-cylinder fuel injection.

That is, FIGS. 4A, 4C, and 4
As shown in (d), when the control mode is switched from the cylinder-stop mode to the all-cylinder mode, the OCVs 26 and 27 are immediately switched from the cylinder-stop mode to the all-cylinder (low-speed) mode, and the ISC 64 is also simultaneously stopped. The cylinder position is switched to the all-cylinder position, but for fuel supply, fuel injection is not injected into the three cylinders until a predetermined period T1 has elapsed.

Next, the process proceeds to step A3, where it is determined whether or not a predetermined period T2 has elapsed from the start of the three-cylinder fuel injection. Then, similarly to the above-described step A1, the vehicle travels through the NO route until the predetermined period T2 elapses. When the predetermined period T2 has elapsed, the process proceeds to step A through the YES route.
Then, the ignition timing is retarded. In this ignition timing control, as shown in FIG. 4E, the ignition timing is conventionally gradually changed at a predetermined gradient when the three-cylinder fuel injection is started. When the predetermined period T2 elapses after the start of the ignition timing, the ignition timing is retarded in consideration of the increase in the engine torque. After the retard, the ignition timing is changed at 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 conventionally changed almost stepwise, becomes smoother. Thereafter, the process proceeds to step A5, in which it is determined whether or not a predetermined period T3 has elapsed since the start of the three-cylinder fuel injection. If it is determined that the predetermined period T3 has elapsed, the process proceeds to next step A6 in which all cylinders are started. 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, in which it is determined whether or not a predetermined period T4 has elapsed since the fuel injection in 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 account the increase in engine torque due to the start of all-cylinder fuel injection, and in accordance with the timing at which the engine torque increases (= predetermined period T4),
The ignition timing is retarded. After the retard, the ignition timing is changed at the same gradient as the conventional one, and is fixed at the conventional low-speed operation ignition timing (see FIG. 4E).

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 stop mode.
When the mode is switched to the mode, the change characteristic of the engine torque can be made smooth, and the shock accompanying the increase in the engine torque hardly occurs. As a result, the driver does not feel discomfort, and the mode can be switched between the cylinder-stop mode and the all-cylinder (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. FIG. 7 is a flowchart for explaining the operation. In the second embodiment, the specific configuration of the engine is omitted, but the configuration of the engine itself is the same as that of the first embodiment, and only the content of the control is different. That is, this engine is also configured as an in-line four-cylinder engine as shown in FIG. 2, and includes an all-cylinder operation mode (all-cylinder mode) including a low-speed operation mode and a high-speed operation mode, and a throttle opening TPS and engine rotation. It is configured to be able to switch between a cylinder stop mode in which the first and fourth cylinders are closed based on the number Ne and the like.

In the second embodiment, the ignition timing is controlled by the ignition timing control means 73 so that the retard of the ignition timing at the start of the fuel supply is given a time difference when switching from the cylinder-stop mode to the all-cylinder mode. It is set so that the fuel supply is performed only for the cylinder whose fuel supply is started last among the cylinders that are started. This is shown in FIG.
Explaining with reference to time charts (1) to (f), three-cylinder fuel injection is started after a lapse of a predetermined period T1 from the switching from the cylinder-stop mode to the all-cylinder mode [FIGS.
(B)]. At this time, the ignition timing of the ignition means 75 is changed at a predetermined gradient similar to that in the normal low-speed mode, as shown in FIG. Accordingly, the engine torque when the predetermined period T2 has elapsed from the time of the three-cylinder fuel injection changes stepwise as shown in FIG.

Then, the four-cylinder fuel injection starts, and when a predetermined period T4 has elapsed from the time of the fuel injection, the ignition timing is retarded by the ignition timing control means 73 to smoothly reduce the engine torque as shown in FIG. The characteristic is to be made. Since the internal combustion engine with a variable cylinder mechanism according to the second embodiment of the present invention is configured as described above, the fuel injection timing and the fuel ignition timing are controlled in accordance with, for example, a flowchart shown in FIG.

First, as shown in FIG. 7, when there is a cylinder deactivation release instruction (that is, an instruction to switch to the all cylinders mode), the process proceeds to step B1, step B7, and step B8 simultaneously.
In step B7, the operation of the OCVs 26 and 27 (see FIG. 3) is controlled to switch from the cylinder-stop mode to the all-cylinder (low-speed) mode. In step B8, ISC64 (FIG. 3)
Is switched from the cylinder rest position to the low speed position.

In step B1, it is determined whether or not a predetermined period T1 has elapsed from the time of the cylinder deactivation release instruction. If the predetermined period T1 has not elapsed, the routine passes through the NO route until the time T1 has elapsed. Pass through. If a predetermined period T1 has elapsed since the cylinder deactivation release instruction, YES
Then, the routine proceeds to step B2, in which fuel injection is started in any one of the first and fourth cylinders, and the three-cylinder fuel injection is performed.

That is, FIGS. 6A, 6C, and 6
As shown in (d), when the control mode is switched from the cylinder-stop mode to the all-cylinder mode, the OCVs 26 and 27 are immediately switched from the cylinder-stop mode to the all-cylinder (low-speed) mode, and the ISC 64 is also simultaneously stopped. The cylinder position is switched to the all-cylinder position. However, for the fuel supply target 29, fuel injection is not injected into the three cylinders until the predetermined period T1 has elapsed.

Then, the process proceeds to step B3, where it is determined whether or not a predetermined period T3 has elapsed since the start of the three-cylinder fuel injection. When it is determined that the predetermined period T3 has elapsed,
Proceeding to the next step B4, fuel injection of all cylinders is started. That is, as shown in FIG. 6E, unlike the first embodiment, the ignition timing is not retarded even when the three-cylinder fuel injection is started, and the ignition timing is controlled to the conventional low-speed mode. . As a result, as shown in the engine torque characteristic diagram of FIG.
Although the engine torque fluctuates in a step-like manner when the time has elapsed, the fluctuation of the engine torque during three-cylinder fuel injection does not directly cause a large shock, and therefore does not cause discomfort to the driver.

Next, the process proceeds from step B4 to step B5, and it is determined whether or not a predetermined period T4 has elapsed since the fuel injection in all cylinders in step B4. If it is determined that the predetermined period T4 has elapsed, the process proceeds to step B6.
And the ignition timing is retarded. This predetermined period T4
Is based on the consideration of the increase in engine torque due to the start of fuel injection in all cylinders, and the ignition timing is retarded in accordance with the timing at which the engine torque increases (= predetermined period T4). It is. Further, after this retard, the ignition timing is changed at the same gradient as the conventional gradient, and is fixed to the low-speed operation ignition timing when it coincides with the conventional low-speed operation ignition timing [FIG.
(E)).

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

As a result, the driver does not feel uncomfortable and can switch from the cylinder-stop mode to the all-cylinder (low-speed) mode without impairing drivability. Next, a 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 configured as a V-type six-cylinder engine. In the cylinder-stop mode, three cylinders in one bank are closed and three cylinders in the other bank are operated. ing. Also in this V-type six-cylinder engine, the structure of the valve train of each cylinder is configured in the same manner as in the first embodiment, and all-cylinder mode in which all cylinders operate, throttle opening TPS and engine It is configured to be able to switch between a cylinder-stop mode in which one bank is closed based on the rotation speed Ne and the like.

That is, the V-type six-cylinder engine according to the third embodiment and the in-line four-cylinder engine according to the first embodiment are different from each other only in the cylinder configuration. In such a V-type six-cylinder engine, when the mode is switched from the cylinder-stop mode to the all-cylinder mode,
The operation is switched from the three-cylinder operation to the six-cylinder operation. In the present embodiment, fuel supply to each injector is sequentially started for the three cylinders whose operation is restarted at this time while giving a time difference by the fuel supply control means. The ignition timing at the start of fuel supply by the ignition timing control means is set to be retarded for all cylinders for which fuel supply is sequentially started. Since the internal combustion engine with a variable cylinder mechanism according to the third embodiment of the present invention is configured as described above, the fuel injection timing and the fuel ignition timing are controlled, for example, according to a flowchart shown in FIG.

That is, when there is a cylinder deactivation release instruction, the process proceeds to step C1, step C13, and step C14 at the same time. At step C13, the operation of the OCV is controlled to switch from the cylinder deactivation mode to the all cylinder (low speed) mode. In step C14, the ISC is switched from the cylinder rest position to the low speed position. In step C1, it is determined whether or not a predetermined period T1 has elapsed from the cylinder stop release command time. If the predetermined period T1 has not elapsed, the process goes through the route of NO and passes through this routine until the time T1 elapses.

Then, for a predetermined period T1 from the cylinder deactivation release command.
After elapse, the process proceeds to step C2 via the YES route, and starts fuel injection to any of the three cylinders that have been closed so far to perform four-cylinder fuel injection. Next, the process proceeds to step C3, where it is determined whether a predetermined period T2 has elapsed from the start of the four-cylinder fuel injection. Then, similarly to the above-described step C1, the vehicle passes through the NO route until the predetermined period T2 elapses. When the predetermined period T2 has elapsed, the process proceeds to step C4 via a YES route, and the ignition timing is retarded.

Thereafter, the process proceeds to step C5. Step C
At 5, it is determined whether a predetermined period T3 has elapsed since the start of the four-cylinder fuel injection. If it is determined that the predetermined period T3 has elapsed, the routine proceeds to the next step C6, where fuel injection of the five cylinders is started. 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 the 5-cylinder fuel injection in step C6
It is determined whether four has elapsed. Here, the predetermined period T4
Is determined to have elapsed, the process proceeds to step C8,
The ignition timing is retarded.

This predetermined period T4 also takes into account the increase in engine torque due to the start of all-cylinder fuel injection, and ignition is performed in accordance with the timing at which engine torque increases (predetermined period T4). The time is being retarded. Thereafter, the process proceeds to step C9,
Here, it is determined whether or not a predetermined period T5 has elapsed from the start of the five-cylinder fuel injection, and the process passes through the NO route until the predetermined period T5 has elapsed. After the lapse of the predetermined period T5, the process proceeds to step C10 via a YES route, and six-cylinder fuel injection (all-cylinder fuel injection) is performed.

Then, the process proceeds to step C11. In step C11, a predetermined period T6 from the start of fuel injection in 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 six-cylinder engine according to the present embodiment, when switching from the cylinder-stop mode to the all-cylinder mode, the fuel supply control means sequentially supplies fuel to each injector while giving a time difference to 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 six cylinder The engine can be smoothly switched between the cylinder-stop mode and the all-cylinder mode.

Next, a fourth embodiment of the present invention will be described. FIG. 9 is a flow chart for explaining the operation of an internal combustion engine with a variable cylinder mechanism as a fourth embodiment of the present invention. The fourth embodiment is configured as the same V-type six-cylinder engine as the third embodiment. In the cylinder-stop mode, three cylinders in one bank are closed and three cylinders in the other bank operate. It is configured as follows. Also in this V-type six-cylinder engine, the structure of the valve train of each cylinder is configured in the same manner as in the first embodiment.

That is, the V-type six-cylinder engine of the fourth embodiment is different from the in-line four-cylinder engine of the first embodiment only in the configuration of the cylinders. . In this embodiment, when the mode is switched from the cylinder-stop mode to the all-cylinder mode, the fuel supply to the respective injectors is sequentially started while giving a time difference by the fuel supply control means for the three cylinders to be restarted at this time, and the ignition timing control is performed. The retard of the ignition timing at the start of the fuel supply by the means is set so as to be performed only for the cylinder to which the fuel supply is started last among the cylinders to which the fuel supply is sequentially started.

Since the internal combustion engine with a variable cylinder mechanism according to 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, for example, a flowchart shown in FIG. You. That is, when there is a cylinder release instruction from the ECU, step D
The process simultaneously proceeds to step D9 and step D10. At step D9, the operation of the OCV is controlled to switch from the cylinder-stop mode to the all-cylinder (low-speed) mode. In step D10, the ISC is switched from the cylinder rest position to the low speed position.

In step D1, it is determined whether or not a predetermined period T1 has elapsed from the cylinder deactivation release command time. If the predetermined period T1 has not elapsed, the routine passes through the NO route until the time T1 has elapsed. Pass through. If a predetermined period T1 has elapsed since the cylinder deactivation release instruction, YES
Then, the routine proceeds to step D2, in which fuel injection is started in any one of the three cylinders that have been closed so far to perform four-cylinder fuel injection.

Thereafter, 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 the fuel injection of the four cylinders. If it is determined that the predetermined period T3 has elapsed, the process proceeds to the next step D4 to start fuel injection of the five cylinders. Next, the process proceeds to step D5, where it is determined whether or not a predetermined period T5 has elapsed since the start of the five-cylinder fuel injection, and the process passes through the NO route until the predetermined period T5 has elapsed. When the predetermined period T5 has elapsed, the process proceeds to step D6 via a YES route, and six-cylinder fuel injection (all-cylinder fuel injection) is performed.

Then, the process proceeds to step D7. In step D7, it is determined whether a predetermined period T6 has elapsed since the start of fuel injection in all cylinders. If it is determined that the predetermined period T6 has elapsed, the routine proceeds to the next step D8, where the ignition timing is retarded. In the V-type six-cylinder engine according to the present embodiment, when switching from the cylinder-stop mode to the all-cylinder mode, the fuel supply control means sequentially supplies fuel to each injector while giving a time difference to the three cylinders whose operation is restarted. Starting, and the ignition timing is retarded only for the cylinder for which fuel supply is started last among the cylinders for which fuel supply is sequentially started. Can be removed.

Thus, it is possible to switch from the cylinder-stop mode to the all-cylinder (low-speed) mode without impairing drivability. In addition, the above-mentioned first to first
In the fourth embodiment, when any of the following conditions is satisfied, the ignition retard by the above-described ignition timing control means 73 is immediately interrupted, and normal ignition timing control is performed. In the case of sudden acceleration The rotation speed range where the switching shock is small The throttle opening range where the switching shock is small When the shift is changed to a range other than the D range Any of the above conditions (1) to (4) can be detected by a known sensor or the like provided in the vehicle. Then, based on the detection information from each sensor, if any of these conditions is met, normal ignition timing control is performed.

Incidentally, 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 will be described in which the control according to the present invention is combined with other control of the engine. FIG. 10 is a schematic diagram showing the configuration of a control system according to the fifth embodiment. As shown in FIG.
, The throttle opening TPS, the engine speed Ne, the oxygen concentration O ₂ , information on whether or not the automatic transmission is shifting gears, and the like are taken in. In addition, the ECU 32
Mode setting means 80 for setting the operation mode of the engine to either the cylinder-stop mode or the all-cylinder mode, and solenoid valve control means for controlling the operation of the solenoid valve (OCV) 91 in accordance with the setting by the mode setting means 80 81, an ISC control means 82 for controlling the operation of a bypass type idle speed controller (ISC) 92, a fuel injection control means 83 for controlling a fuel injection means 93, and an ignition means (spark plug) 9
An ignition timing control means 84 for controlling the ignition timing of No. 4 and a 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, as in the first embodiment, the throttle opening TPS1 in the load region higher than the cross point is set as the switching point, and the cylinder closing mode or the full cylinder mode is set. Set the cylinder mode. However, when it is necessary to switch from the all-cylinder mode to the cylinder-stop mode due to this setting, if the automatic transmission is in the shifting operation, it does not switch to the cylinder-stop mode until the shifting operation is completed and waits. After the shift operation is completed, the mode is switched to the cylinder-stop mode.

The solenoid valve control means 81 controls the operation of each solenoid valve (OCV) 91 in a state corresponding to the mode set by the mode setting means 80, and sets the cylinder-stop / all-cylinder switching mechanism 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 the idle position so that the idle speed becomes lower during the idle mode, and the idle speed becomes higher during the full mode. The opening position of the valve interposed in the bypass is controlled to all cylinder positions. 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 control of whether or not to perform fuel injection.
Of course, in the all-cylinder mode, fuel is injected into all cylinders in principle, but in the closed-cylinder mode, fuel is not injected into cylinders that are in a closed state. Then, at the time of switching from the cylinder-stop mode to the all-cylinder mode, after a predetermined period T1 has passed after the mode switching, fuel injection to the cylinder that has newly started intake is started.
In this case as well, the fuel injection is not started simultaneously for all the cylinders that have newly started the intake, but is started one by one with a time difference.

For example, taking a four-cylinder engine as an example,
The cylinders to be closed are, for example, two cylinders, a first cylinder and a fourth cylinder. When switching from the closed cylinder mode to the all-cylinder mode,
The introduction of intake air into these first and fourth cylinders is started. In the fuel injection control means 83, the first cylinder and the fourth cylinder
Even if the introduction of intake air to the cylinder is started, fuel injection is not started at the same time. For example, after a predetermined period T1 has elapsed after mode switching, first, fuel injection to the first cylinder is started to be in a three-cylinder fuel injection state. After a predetermined period T3 has elapsed, fuel injection to the first cylinder is started to bring all cylinders into fuel injection. 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 to be increased stepwise by such stepwise fuel injection. As another procedure for 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 a period of time.

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

The switching load (switching throttle opening TPS) in the air-fuel ratio control mode changes depending on the engine speed.
S2 is larger than the cross point and smaller than the switching throttle opening TPS1 of 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 which occurs in response to the start of fuel injection into a new cylinder when switching from the cylinder-stop mode to the all-cylinder mode. The retard control is performed. This suppression of the ignition timing is intended to make the output torque of the engine increase more slowly when switching from the cylinder-stop mode to the all-cylinder mode. When fuel injection is started from a cylinder-stopped state to an activated cylinder, the output torque suddenly increases in a step-like manner.
At this time, if the ignition timing is temporarily retarded, the increase in the output torque is suppressed, and the output torque increases gradually, so that the mode switching shock is reduced. Note that the retard of the ignition timing is slightly delayed from the start of fuel injection to the cylinder that has started operation (waiting for periods T2 and T4), and the timing at which the output torque actually increases after the start of fuel injection is considered. Be executed.

The power generation control means 85 performs a control (power generation cut control) to stop the power generation by the generator 95 when the engine is rotating at high speed in the cylinder-stop mode. Of course, under other conditions, the power generation cut control is canceled and the generator 9
5 to generate power. As a result, an attempt is made to suppress a switching shock which is a problem when switching from the cylinder-stop mode to the all-cylinder mode when the engine is rotating at high speed.

In the internal combustion engine with a variable cylinder mechanism according to the fifth embodiment of the present invention, the control system is configured as described above.
For example, as shown in FIG. 11, each control is performed. That is, as shown in FIG. 11, in step S10, the throttle opening TPS, engine speed Ne, the oxygen concentration O ₂ and the automatic transmission reads the information of whether or not the speed change, 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. In other words, if the cylinder-stop / all-cylinder flag F is 1, the current cylinder mode is set, and if the flag F is 0, the cylinder is the current cylinder-stop mode.

If the current mode is the all-cylinder mode, the flow advances to step S14 to set the throttle opening TPS to the switching point value TPS1.
Then, it is determined whether or not to switch to the cylinder deactivation mode. If the TPS is less than TPS1, it is necessary to switch to the cylinder-stop mode. At this time, the process proceeds to step S16 to determine whether or not the automatic transmission (AT) is performing a switching operation. If the automatic transmission is performing the switching operation, the process proceeds to step S16, and waits until the switching operation is completed to execute the switching to the cylinder-stop mode. Thus, the switching to the cylinder-stop mode is not performed during the switching operation of the transmission. Therefore, when switching from the all-cylinder mode to the cylinder-stop mode during the switching operation of the transmission, a large switching shock occurs, but this is avoided.

Next, the routine proceeds to step S20, in which the operating state in the cylinder-stop mode is set. When the cylinder deactivation mode is set, select a map for cylinder deactivation as O ₂ feedback zone determination map (step S22), and step S3
The cylinder-stop air-fuel ratio control from 0 to S36 is executed. Also,
The solenoid valve (OCV) 81 is set to the cylinder stop mode (step S2).
4) Control various objects to be interlocked with the closed cylinder, such as controlling the ISC 92 to the closed cylinder position, to the closed cylinder side (step S26). Furthermore, the cylinder deactivation mode, the engine speed Ne at the predetermined rotational speed Ne ₁ or more high speed region, the determination of step S28, performs power generation cut control proceeds to step S40. The engine speed Ne is equal to the predetermined speed N
If not e ₁ or more high speed region, the step S28, executes a power generation by releasing the power generation cut control proceeds to step S42.

[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 Judge whether it is in the feedback zone or not. Throttle opening TP
If S is less than the switching throttle opening TPS2 corresponding to the engine speed Ne at this time, it is an O ₂ feedback zone, and the process proceeds to step S32 to execute O ₂ feedback control. Detected throttle opening TPS is rich zone if switching throttle opening TPS2 or more, the process proceeds to step S34, to release the O ₂ feedback control, performs rich control at step S36. Thereafter, the process proceeds to step S38, in which the closed cylinder / all cylinder flag F is set to 0.
(Cylinder rest mode).

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

When the all-cylinder mode is set, the solenoid valve (OC
V) 81 is set to the all-cylinder mode (step S48), and the ISC
Various control objects to be linked with all the cylinders are controlled toward all the cylinders, such as controlling the 92 to the all cylinder position (Step S50). Further, the process proceeds to step S52 to cancel the power generation cut control and execute power generation. Immediately after the mode is switched to the all-cylinder mode, the flag F is 0, and the process proceeds to step S56 according to the determination in step S54, and after waiting for a predetermined period T1,
Proceeds to step S58, the selected map for all cylinders as O ₂ feedback zone determination map, and 3-cylinder fuel injection state only the start of the fuel injection one of cut unusual cylinder actuation from cylinder deactivation (Step S60). Further, after waiting for a predetermined period T2 in step S62, the ignition timing is retarded (step S64). Then, after waiting for a predetermined period T3 from the three-cylinder fuel injection state in step S66, the fuel injection to the remaining cylinders is started to be the all-cylinder fuel injection state (step S6).
8). Further, after waiting for a predetermined period T4 in step S70, the ignition timing is retarded again (step S70).
72).

When the all-cylinder fuel injection state is established, the all-cylinder air-fuel ratio control in steps S74 to S80 is executed. That is, first, in step S74, all cylinder O
_{(2) From} the detected engine speed Ne and the throttle opening TPS using the feedback zone determination map,
₂ Judge whether it is in the feedback zone or not. Throttle opening TPS is O ₂ feedback zone if switching throttle opening less than TPS2 according to the engine rotational speed Ne at this time, the process proceeds to step S76, to implement the O ₂ feedback control. Detected throttle opening TPS is rich zone if switching throttle opening TPS2 or more, the process proceeds to step S78, to release the O ₂ feedback control, performs rich control at step S80. Thereafter, the process proceeds to step S82, and the closed cylinder all cylinder flag F is set to 1 (all cylinder mode).

In each of the above embodiments, a four-cylinder engine has been described. However, the engine (internal combustion engine) to which the present invention can be applied is not limited to the number of cylinders, the in-line type, the V type, and the like. .

[0096]

As described in detail above, according to the first aspect of the present invention, there is provided an internal combustion engine having a plurality of cylinders, wherein all of the plurality of cylinders are operated. A variable cylinder mechanism capable of switching between a cylinder mode and a closed cylinder mode in which the operation of some of the plurality of cylinders is stopped by shutting off intake air to some of the plurality of cylinders; and a load on the internal combustion engine. Variable cylinder control means for controlling the operation of the variable cylinder mechanism to operate in the cylinder-stop mode when the engine load is small and to operate in the full-cylinder mode when the engine load is large based on the state; Fuel supply means capable of 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 ignition means And the rest A variable variable set so that the operation of the plurality of cylinders is stopped in the mode, and the internal combustion engine is set to stop the fuel supply to the cylinder in the cylinder stopped through the fuel supply control means when the cylinder stop mode is selected. In the internal combustion engine with a cylinder mechanism, when the fuel supply control means is switched from the cylinder-stop mode to the all-cylinder mode, fuel supply is sequentially started while giving a time difference to the plurality of cylinders for which the introduction of intake air has been started. At the same time, the ignition timing control means adjusts the output of the internal combustion engine with respect to the start of the fuel supply.
The fuel supply is opened based on the time difference until the fuel starts to increase.
With the configuration in which the ignition timing is set to be retarded later than the starting point , the output of the internal combustion engine can be smoothly increased when switching from the cylinder-stop mode to the all-cylinder mode. Shock can be greatly reduced. Also, there is so new there is no need to provide a component, an advantage that it is possible to realize such shock reduction effect at a low cost.

[0097]

[0098] Further, according to the variable-cylinder mechanism with an internal combustion engine of the present invention described in claim 2, in addition to the above claim 1 Symbol placement, the ignition timing at the start of the fuel supply by the ignition timing control means With the configuration in which the retard is set to be performed for all the cylinders for which fuel supply is sequentially started while giving a time difference when switching from the cylinder-stop mode to the all-cylinder mode, the output of the internal combustion engine is smoothly increased. The switching shock can be greatly reduced at low cost.

[0099] Further, in addition to the above claim 1 Symbol placement,
The retardation of the ignition timing at the start of fuel supply by the ignition timing control means gives a time difference when switching from the cylinder-stop mode to the all-cylinder mode. Is set to be performed only for the cylinders starting to be started (aspect 1),
The switching shock can be reduced by only simple control, and the switching from the cylinder-stop mode to the all-cylinder mode can be executed without giving the driver any discomfort. Moreover, there is an advantage that it is possible to realize such shock reduction effect at a low cost.

Further, the first and second aspects and the first aspect
In addition to the configuration described in any one of the above, when the mode is switched from the cylinder-stop mode to the all-cylinder mode, the fuel supply start control is set to be started with a delay of a predetermined period from the mode switching time. With such a configuration, the output of the internal combustion engine can be smoothly increased, and the switching shock can be reduced at low cost.

[Brief description of the 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 the internal combustion engine with a variable cylinder mechanism as the 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 flowchart illustrating an 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 an operation in an internal combustion engine with a variable cylinder mechanism as a second embodiment of the present invention.

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

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

FIG. 9 is a flowchart for explaining an operation in an internal combustion engine with a variable cylinder mechanism as a 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 flowchart illustrating the operation of an internal combustion engine with a variable cylinder mechanism according to a fifth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine (internal combustion engine with a variable cylinder mechanism) 2 Cylinder head 4 DOHC type valve train 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 (Low-speed OCV for low cylinder) 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 position sensor 37 surge tank 38 air cleaner 40 throttle valve 41 throttle rotary shaft 42 valve drive actuator 44 fuel source 46 of the valve 40 O ₂ sensor 48 variable cylinder mechanism 50 cylinder deactivation, all-cylinder switching mechanism (intake and exhaust valves Stop mechanism) 51, 52 Rocker arm 51 , 52A fitting holes 53, 54 hydraulic pistons 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 path FS fuel supply Means IM Intake manifold IR Intake path ML, MH Low / high switching means (mode switching mechanism) 73 Ignition timing control means 71 Fuel supply control means 75 Ignition means (spark plug) 80 Mode setting means 81 Solenoid valve control means 82 ISC control means 83 Fuel injection control means 84 Ignition timing control means 85 Control means 91 Solenoid valve (OCV) 92 Bypass idle speed controller (IS
C) 93 Fuel injection means 94 Ignition means (spark plug) 95 Generator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI F02D 43/00 301 F02D 43/00 301H 301Z F02P 5/15 F02P 5/15 B (72) Inventor Katsunori Ueda Shiba, Minato-ku, Tokyo 5-33-8 Mitsubishi Motors Corporation (72) Inventor Hideo Shimita 5-33-8 Shiba Minato-ku, Tokyo 5-33-8 Mitsubishi Motors Corporation (72) Inventor Hideo Nakai Minato-ku, Tokyo Shiba 5-chome No. 33-8 Mitsubishi Motors Corporation (56) References JP-A-59-110858 (JP, A) JP-A-60-50238 (JP, A) JP-A-63-1759 (JP, A) JP-A-5-180135 (JP, A) JP-A-5-195852 (JP, A) JP-A-56-154138 (JP, A) Full-scale application Sho-59-131937 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) F02D 17/02 F02D 13 / 06 F02D 41/02 F02D 41/36 F02D 43/00 F02P 5/15

Claims (2)

(57) [Claims] An internal combustion engine having a plurality of cylinders, wherein the one-cylinder mode in which all of the plurality of cylinders are operated and the introduction of intake air to some of the plurality of cylinders are cut off. A variable cylinder mechanism capable of switching between a cylinder stop mode for stopping operation of the cylinders of the section, and a case where the engine load is operated based on the load state of the internal combustion engine when the engine load is small and the engine load is large. Variable cylinder control means for controlling the operation of the variable cylinder mechanism so as to operate in the all-cylinder mode, fuel supply means capable of supplying fuel to each cylinder, presence or absence of fuel supply by the fuel supply means, Fuel supply control means for controlling fuel supply timing at the time of fuel supply; and ignition timing control means for controlling ignition means, wherein the operation of the plurality of cylinders is set to be stopped in the cylinder closing mode; Internal combustion engine When the cylinder stall mode is selected, an internal combustion engine with a variable cylinder mechanism set so as to stop supplying fuel to the cylinder during the cylinder stall through the fuel supply control means. When switched to all cylinder mode,
The fuel supply is started sequentially while giving a time difference to the plurality of cylinders for which the intake introduction has been started, and the ignition timing control means increases the output of the internal combustion engine with respect to the start of the fuel supply.
Start time of the fuel supply based on the time difference before starting
An internal combustion engine with a variable cylinder mechanism, wherein the ignition timing is set to be retarded even later . 2. The retardation of the ignition timing at the start of fuel supply by the ignition timing control means is changed from the cylinder deactivation mode to all cylinders.
Open fuel supply sequentially while giving time difference when switching to mode
Set to be performed for all starting cylinders
The internal combustion engine with a variable cylinder mechanism according to claim 1, wherein: