JPH08105336A - Internal combustion engine having variable cylinder mechanism - Google Patents

Abstract

PURPOSE: To check the occurrence of a large switching shock in 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 actuation of the variable cylinder mechanism 48 so that an engine is operated in a cylinder resting mode when an engine load is small and it is operated in a whole cylinder mode when the engine load is large according to a load condition of the internal combustion engine and a power generation control means 76 to control actuation of a generator 78 driven by the internal combustion engine. The power generation control means 76 is constituted so as to stop or restrain and control power generation by the generator at cylinder resting mode operation time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an all-cylinder mode in which all cylinders are operated, and an idle mode in which the operation of these cylinders is stopped by shutting off intake air introduction to some of the cylinders. The present invention relates to an internal combustion engine with a variable cylinder mechanism that can switch between cylinder mode.

[0002]

2. Description of the Related Art Conventionally, in a multi-cylinder internal combustion engine, when the engine load is low, intake air is cut off to some cylinders, fuel supply is stopped, and some cylinders are deactivated. Technology has been developed and put into practical use to increase the combustion efficiency of operating cylinders to suppress the generation of harmful exhaust gas and to improve the fuel efficiency by reducing pumping loss by improving the load factor of the engine. .

In this case, the point is how to smoothly switch between the mode in which all cylinders are operated (all cylinder mode) and the mode in which some cylinders are deactivated (cylinder deactivation mode). For example, in Japanese Examined Patent Publication No. 63-21811, the intake manifold pressure at which the engine output torque during the cylinder deactivation mode operation and the engine output torque during the all cylinder mode operation are substantially equal to each other is set as a switching point, and the intake manifold pressure of the engine is changed. A technique is disclosed in which the cylinder deactivation mode is selected when it is smaller than this switching point, and the all cylinders mode is selected when the intake manifold pressure of the engine is equal to or higher than this switching point.

The intake manifold pressure of the engine corresponds to the load of the engine represented by the throttle valve opening. However, in a general internal combustion engine in which intake is introduced through the same throttle valve, the engine output torque is the engine. The characteristics with respect to the load (throttle valve opening) are as shown in FIG. That is,
Within a certain range, as the engine load increases, the engine output torque also increases.However, at low load, all-cylinder operation has a greater effect of pumping loss than cylinder-stop operation, so cylinder operation at the same load The output torque is larger in the case of 1. However, due to the absolute difference in the combustion energy at the time of high load, the output torque in the case of all-cylinder operation is naturally larger than that in the cylinder deactivation operation.

As described above, there is an intersection point (cross point) where the output torques are equal, and by using this cross point as a switching point to switch the cylinder deactivation mode to the all cylinders mode, a shock at the time of mode switching is avoided. It is possible to switch smoothly.

[0006]

By the way, in order to further improve the fuel efficiency of the engine and suppress the generation of harmful exhaust gas, the engine must be operated in the cylinder deactivation mode up to a load higher than the cross point. Can be considered. In particular, in vehicles having an automatic transmission connected to an engine through a fluid coupling, which has become widespread in automobiles, there is a torque cross due to the fluid coupling, so that the demand for improvement in fuel consumption is more remarkable.

However, in the high load region above the cross point, as shown in FIG. 10, when the cylinder deactivation mode is set, the output torque of the engine becomes smaller than that in the all cylinder mode. When switching from the cylinder deactivation mode to the all-cylinder mode in a region, the output torque suddenly increases, causing a switching shock. In particular, this switching shock from the cylinder deactivation mode to the all cylinders mode is remarkable when the engine speed is high.

Further, Japanese Patent Application No. 5-1719 filed by the present applicant
No. 65 discloses a technique of reducing the power generation amount of the alternator to reduce the torque shock at this time after switching from the all cylinder mode to the all cylinder mode, but at the time of switching from the all cylinder mode to the all cylinder mode. The shock of is not considered. The present invention was devised in view of such problems, and an object thereof is to provide an internal combustion engine with a variable cylinder mechanism, which prevents a large switching shock from occurring when switching from the cylinder deactivation mode to the all cylinders mode. To do.

[0009]

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, In an internal combustion engine with a variable cylinder mechanism having a power generation control means for controlling the operation of a power generator driven by the internal combustion engine, the power generation control means stops or suppresses power generation by the power generator during the cylinder cutoff mode operation. To control It is characterized in that it is set.

According to a second aspect of the present invention, in the internal combustion engine with a variable cylinder mechanism according to the first aspect, the power generation control means operates during the cylinder deactivation mode operation in the high speed rotation range of the internal combustion engine. It is characterized in that it is set so as to perform control to stop or suppress power generation by the generator. Further, in the internal combustion engine with a variable cylinder mechanism according to a third aspect of the present invention, in the configuration according to the first or second aspect, the variable cylinder control means causes the engine output torque during the cylinder deactivation mode operation and the full cylinder mode. It is set to switch between the cylinder deactivation mode operation and the all cylinder mode operation with an engine load larger than the reference engine load with which the engine output torque during operation is substantially equal. It is characterized by that.

[0011]

In the internal combustion engine with a variable cylinder mechanism according to the present invention as set forth in claim 1, the variable cylinder control means operates in the cylinder deactivation mode when the engine load is small based on the load state of the internal combustion engine. When is large, the operation of the variable cylinder mechanism is controlled so as to operate in the all cylinder mode. The power generation control means controls to stop or suppress power generation by the generator during the cylinder cutoff mode operation. This eliminates the load of the generator during the cylinder deactivation mode operation and increases the engine output during the cylinder deactivation mode operation. Then, when the control to stop or suppress the power generation is released at the same time as switching from the cylinder deactivation mode operation to the all cylinder mode operation, the load of the generator is added when the operation is switched to the all cylinder mode operation, and the output increase of the engine is suppressed. As a result, the shock at the time of switching is reduced.

In the internal combustion engine with a variable cylinder mechanism according to the second aspect of the present invention, the power generation control means stops the power generation by the generator during the cylinder cutoff mode operation in the high speed rotation region of the internal combustion engine. Since the suppression control is performed, the shock at the time of switching from the cylinder deactivation mode to the full cylinder mode in the high speed rotation region of the internal combustion engine is reduced, while the mode switching shock does not pose a problem. Power generation by the power generator can be executed outside the rotation region, and the mode switching shock can be reduced while securing sufficient opportunities for power generation.

In the internal combustion engine with a variable cylinder mechanism according to the present invention as set forth in claim 3, the variable cylinder control means controls the engine output torque during the cylinder deactivation mode operation and the engine output torque during the all cylinder mode operation. When the engine load is larger than the reference engine load, the switching between the cylinder deactivation mode operation and the all cylinder mode operation is performed. When the engine load is larger than the reference engine load, the output torque of the engine is smaller in the cylinder deactivation mode operation than in the all cylinder mode operation in the original engine characteristics, but the power generation control means, during the cylinder deactivation mode operation, Since the control for stopping or suppressing the power generation by the generator is performed, the output torque of the engine during the cylinder deactivation mode operation increases by this amount, and approaches the output torque of the engine during the all cylinder mode operation. Therefore, in the high speed rotation region of the internal combustion engine, the shock when switching from the cylinder deactivation mode to the full cylinder mode is reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, an internal combustion engine with a variable cylinder mechanism as a first embodiment of the present invention will be described with reference to FIGS. Now, as shown in FIG. 2, the internal combustion engine with a variable cylinder mechanism of the present embodiment is a fuel injection engine (hereinafter, the internal combustion engine is referred to as an engine) 1 that uses DOHC in-line 4-cylinder gasoline fuel.

In the cylinder head 2 of this engine 1,
One end of an intake manifold IM capable of communicating with each cylinder is attached, and a surge tank 37 is attached to the other end of the intake manifold IM to form an intake passage IR, and the intake passage IR is further connected to the surge tank 37. It has an intake pipe and an air cleaner 38 which communicate with each other. An exhaust manifold EM capable of communicating with each cylinder is attached to the other side of the cylinder head 2, and an exhaust passage ER including an exhaust pipe and the like is connected to the exhaust manifold EM.

A throttle valve 40 is arranged downstream of the air cleaner 38 in the intake passage IR, and a rotary shaft 41 of the throttle valve 40 is rotated by a valve drive actuator 42 having a stepper motor. It is configured. The valve drive actuator 42 is connected to an engine control unit (ECU) 32, which will be described later, and is configured to perform 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 U32 is attached. Further, a negative pressure sensor 35 that outputs a negative pressure signal Pb corresponding to the negative pressure of the intake pipe is attached to 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 opened / closed by an exhaust port (not shown). Each intake / exhaust valve is a well-known DOHC type valve operating valve. It is driven by the system 4. The valve train 4 includes intake / exhaust cam shafts 5, 6 attached to the cylinder head 2 and intake / exhaust rocker shafts 7, 8.

Timing gears 9 and 10 are fixed to one ends of the intake and exhaust cam shafts 5 and 6, respectively.
0 is connected to the 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 constructed so as to be opened and closed by a well-known valve system, one example of which is as follows:
It is disclosed in the specification and drawings of Japanese Patent Application No. 4-232322 filed by the present applicant. This valve system has a low / high switching means (mode switching mechanism) ML, M having a cylinder deactivation / all-cylinder switching mechanism 50 (see FIG. 3) which is a main part of the variable cylinder mechanism 48.
H is installed. The mode switching mechanisms ML and MH have low electromagnetic valves 26 for the 1 and 4 cylinders and low electromagnetic valves 30 for the 2 and 3 cylinders, which connect the switching oil passage 23 to the hydraulic pump 25 in an intermittent manner. In addition, the mode switching mechanism ML,
The MH includes a high solenoid valve 27 for the 1 and 4 cylinders and a high solenoid valve 31 for the 2 and 3 cylinders, which connects the switching oil passage 24 to the hydraulic pump 25 in a discontinuous manner. The hydraulic pump 25 is communicatively connected to the oil tank as shown.

Each of the low and high solenoid valves 26, 30, 27, 31 is composed of a three-way valve. When each valve is turned on, hydraulic oil for driving a hydraulic piston, which will be described later, is supplied, and when it is turned off, the hydraulic actuator is drained. 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.

Further, 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. With reference to FIG. 3, 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) will be described. However, the rocker arms 51, 5 for opening and closing the intake valve and the exhaust valve are connected to the first and fourth cylinders.
2, 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).

The rocker arms 51 and 52 can be interlocked with a T-lever 55 that can contact and drive an intake valve or an exhaust valve via hydraulic pistons 53 and 54, respectively. The hydraulic pistons 53 and 54 have fitting holes 51A and 52 formed in the rocker arms 51 and 52, respectively.
When the head is inserted into A, the rocker arms 51 and 52 and the T lever 55 are connected so as to operate integrally, and the insertion hole 51
When the head is removed from A, 52A, the rocker arm 51,
The connection between 52 and the T lever 55 is released.

The hydraulic piston 53 is the 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 that includes a low speed cam, the movement of the rocker arm 51 results in the rocker arm 5 moving.
Includes 2 movements. Therefore, the rocker arm 51 is T
When the locker arm 52 is connected to the lever 55,
The T-lever 55 is driven by the high speed cam regardless of non-connection.

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 results in the rocker arm 5 moving.
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 solenoid valve (OCV for high speed) 27, and the hydraulic pressure in the oil chamber 54A is controlled by a low solenoid 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 provided with fuel supply means FS, and the fuel supply means FS injects 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. here,
Explaining the engine control by the ECU 32, E
The CU 32 is configured with a microcomputer as its main part, and performs injector drive control, ignition control, etc. together with the low electromagnetic valves 26, 30 and the high electromagnetic valves 27, 31 according to the operation mode set according to the operation information. Is configured.

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. 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) Performs idle speed control and the like through 64.

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, the throttle opening sensor 36 and the engine speed sensor 33 are connected to the ECU 32.

When the engine load is small, the cylinder deactivation mode is selected, when the engine load is large, the all cylinder low speed mode is selected, and when the engine load is larger, the all cylinder high speed mode is selected. There is. When switching between the cylinder deactivation mode and the all-cylinder mode (all-cylinder low-speed mode) and the switching between the all-cylinder low-speed mode and the all-cylinder low-speed mode in the all-cylinder mode, the load (switching load) serving as a switching reference is set, respectively. Then, the detected engine load can be compared with this switching load.

By the way, in the variable cylinder mechanism of the present engine, the switching throttle opening TPS1 corresponding to the load for deactivating cylinders / all cylinders (first engine load) is given as follows. That is, the output torque of the engine (here, indicated by the average effective pressure Pe corresponding to the output torque) increases the engine load (throttle valve opening TPS) within a certain range, as described in the section of the related art. And the characteristics become as shown in FIGS. 4 and 5. FIG. 5 shows FIG. 4 in more detail. Although the intake pressure itself is different between the cylinder deactivated state and the full cylinder state as shown in FIG. 5A, the average effective pressure Pe corresponding to the output torque of the engine. In the low load, the output torque is larger in the in-cylinder operation than in the all-cylinder operation, but the output torque is larger in the all-cylinder operation than in the in-cylinder operation, and there is an intersection (cross point) where the output torque becomes equal. Conventionally, the cross point is used as a switching point, and if it is less than this, switching is made to the cylinder deactivation mode, and if it is more than this, switching is made to the all cylinder mode.

On the other hand, in the present engine, the switching point is changed to a region where the engine load (throttle valve opening TPS) is larger than this cross point, and the engine load (throttle valve opening TPS) is increased to a large region. The cylinder deactivation mode is maintained to perform the cylinder deactivation mode in a wider operating region, and the fuel consumption is further improved by expanding the range of the cylinder deactivation mode operation.

Specifically, the switching throttle opening (first engine load) TPS1 is set in a load region larger than the load (reference load) corresponding to the cross point, and the engine load, that is, the throttle opening TPS is set to this. The cylinder deactivation mode is selected in a region less than the switching throttle opening TPS1, and the all cylinders mode is selected in a region in which the throttle opening TPS is greater than the switching throttle opening TPS1.

Since the optimum value of the switching load changes depending on the engine speed, the switching load (switching throttle opening TPS1) is set according to the engine speed. Therefore, based on the switching throttle opening TPS1, for example, the engine speed Ne and the engine load (throttle opening)
Select the cylinder deactivation mode and all cylinders mode for TPS 2
A dimension map is provided, and the optimum mode can be selected from the detected engine speed Ne and engine load (throttle opening) TPS based on this map.

The optimum switching load (switching throttle opening TPS1) tends to be set to a smaller value as the engine speed increases. In the mode control means 70, the mode determination unit 70A 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 mode setting unit 70B sets a selection mode, and the intake valve / exhaust valve operation, fuel supply control, idle speed control, and the like are performed according to the setting mode.

The operation control of the intake valve / exhaust valve is performed by 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.

By the way, in this engine, as shown in FIG. 1, an engine-driven generator (alternator) 7 driven through a crankshaft (not shown) of the engine.
8 is provided, and the ECU is provided with power generation control means 76 for controlling the operation of the power generator 80.
The power generation control means 76 includes a power generation cut determination means 76A and a power generation / power generation cut control means 76B.

The power generation cut-off determining means 76A determines that the power generation cut-off control is performed only when the engine speed Ne is higher than the set value Ne ₁ during the cylinder cutoff mode operation. It is determined to cancel the cut control and execute the power generation cut. In the power generation / power generation cut control means 76B, the generator 8 is determined based on this determination result.
It is designed to control the operation of zero.

Since the internal combustion engine with the variable cylinder mechanism as the first embodiment of the present invention is constructed as described above, the switching control between the cylinder deactivation mode and the all cylinders mode is shown in FIGS. As described above, the switching is performed at the switching point in the load area larger than the load (reference load) corresponding to the cross point. Therefore, the cylinder deactivation mode is activated in a load region that is greater than the cross point. In this region, the deactivation of the engine tends to cause an increase in output torque of the engine, resulting in insufficient output. A switching shock is likely to occur when the mode is switched to the all cylinders mode, but with this engine, power generation cut is executed and the power generation load is lost during such a cylinder deactivation mode operation when the engine is rotating at high speed. The engine output in the cylinder deactivation mode operation increases by that amount, and a switching shock is less likely to occur when the cylinder deactivation mode is switched to the all cylinders mode.

That is, in this engine, the operation of the generator 80 is controlled as shown in FIG. 6, for example. That is, first, in the ECU 32, the throttle opening sensor 3
6, each detection value TPS from the engine speed sensor 33,
Ne is read (step A10), and the detected throttle opening TPS is compared with the engine operation mode switching throttle opening TPS1 at the detected engine speed Ne to determine whether it is in the cylinder deactivation mode (step A1).
2).

If the detected throttle opening TPS is less than the switching throttle opening TPS1, the cylinder is in the cylinder deactivation mode, the solenoid valves 27 and 26 are set to the cylinder deactivation mode, and the idle speed control and the like are also set to the cylinder deactivation mode. In the cylinder deactivation mode, the routine proceeds to step A14, where the detected engine speed Ne is compared with the reference speed Ne ₁ to determine whether the engine speed is in the high rotation range. If Ne ≧ Ne _{1, the} engine speed is in the high speed range, and the process proceeds to step A16, where the power generation cut control is executed. Also, Ne ≧ Ne ₁
If not, the process proceeds to step A18, the engine speed is not in the high rotation range, the power generation cut control is canceled, and power generation is executed.

If the detected throttle opening TPS is greater than or equal to the switching throttle opening TPS1, it is the all cylinder mode,
From step A12, the process proceeds to step A18, where the engine speed is not in the high rotation range, the power generation cut control is canceled, and power generation is executed. When the power generation cut control is performed, the loss of engine output is reduced and the usable engine output increases accordingly. Therefore, switching from cylinder deactivation mode to full cylinder mode when the engine is running at high speed cuts the power generation during cylinder deactivation mode operation. The power generation load is eliminated by the control, and the power generation load is restored by canceling the power generation cut control during the all-cylinder mode operation. Therefore, when switching from the cylinder deactivation mode to the all cylinders mode with the engine running at high speed, the engine output usually increases rapidly and a mode switching shock occurs. As a result, a sudden increase in engine output is avoided and a mode switching shock is suppressed.

Further, in a region other than the high-speed rotation region of the engine where the switching shock does not pose a problem, the power generation by the generator 78 is executed, and the switching shock, which is a problem, can be avoided while sufficiently securing the opportunity of power generation. For example, as shown in FIG. 7, the throttle opening TPS is once lowered,
When the all cylinder mode temporarily switches to the cylinder deactivation mode and returns to the all cylinder mode again, the cylinder deactivation mode is activated when the engine speed is high. The target duty D _FR is adjusted to perform power generation cut control. As a result, the current generated by the generator (alternator) 78 decreases, and the output torque of the engine sharply increases at the time of returning from the cylinder deactivation mode to the all cylinders mode as indicated by the broken line due to the reduction of the engine load. As shown by, the sudden increase is suppressed and the switching shock is reduced.

Further, the engine output itself in the cylinder deactivation mode is increased by the power generation cut control, so that the output shortage in the cylinder deactivation mode can be suppressed, and the driver does not feel the output shortage while expanding the cylinder deactivation mode operation range. You can In addition,
In this embodiment, the power generation cut control is performed when the engine is in the high speed rotation state during the cylinder deactivation mode operation. However, instead of the power generation cut control, the power generation suppression control is performed to reduce the power generation amount and reduce the power generation load. May be. It is also possible to always perform the power generation cut control or the power generation suppression control during the cylinder deactivation mode operation regardless of the engine rotation state.

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 second embodiment, an example in which the control according to the present invention is combined with other control of the engine will be described. FIG. 8 is a schematic diagram showing the configuration of the control system according to the second embodiment. As shown in FIG. 8, the ECU 32 includes a throttle opening sensor (throttle position sensor) 36, an engine speed sensor 33, and an oxygen sensor. From the concentration sensor 46 and the automatic transmission control means 74, information such as the throttle opening TPS, the engine speed Ne, the oxygen concentration O ₂ and whether or not the automatic transmission is shifting is taken in.

Further, the ECU 32 has a mode setting means 80 for setting the engine operation mode to either the cylinder deactivation mode or the all cylinder mode, and a solenoid valve (OCV) 91 according to the setting by the mode setting means 80. Solenoid valve control means 81 for controlling the operation of the bypass type idle speed controller (ISC) 92, ISC control means 82 for controlling the operation of the bypass type idle speed controller (ISC) 92, fuel injection control means 83 for controlling the fuel injection means 93, and ignition means (ignition means). The ignition timing control means 84 for controlling the ignition timing of the plug 94 and the power generation control means 85 for controlling the operation of the generator 95 driven by the engine 1 are provided.

The mode setting means 80 uses the throttle opening TPS and the engine speed Ne as the switching point, based on the throttle opening TPS and the engine speed Ne, with the throttle opening TPS1 in the higher load range than the cross point as the switching point or in 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.

The solenoid valve control means 81 controls the operation of each solenoid valve (OCV) 91 to a state according to the mode set by the mode setting means 80, and sets the cylinder deactivation / 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 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.

Further, 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 varies 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 second 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. 9, in step S10, 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 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. In other words,
If the all-cylinder flag F is 1, it is currently in the all-cylinder mode, and if the flag F is 0, it is currently in the cylinder-off mode.

If it is currently in the all cylinders mode, 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 operation waits until the switching operation is completed (step S18), and the switching to the cylinder deactivation mode is executed.
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.

[0063] 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 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 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. .

[0068]

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. In the internal combustion engine with a variable cylinder mechanism having a power generation control means for controlling the operation of a power generator driven by the internal combustion engine, the power generation control means stops the power generation by the power generator during the cylinder cutoff mode operation, or I will control to suppress With this configuration, the switching shock associated with the switching from the cylinder deactivation mode operation to the all cylinder mode operation is reduced, and, for example, when the engine is equipped in a vehicle, the drive feeling can be improved. is there.

According to the internal combustion engine with a variable cylinder mechanism of the present invention as defined in claim 2, in the structure of claim 1, the power generation control means operates in the cylinder deactivation mode in the high speed rotation region of the internal combustion engine. At the time, the configuration is set to stop or suppress the power generation by the generator, and it is possible to reduce the mode switching shock from the cylinder deactivation mode operation to the all-cylinder mode operation while securing sufficient opportunities for power generation. The advantage is that the drive feeling can be improved while ensuring the power generation performance.

According to the internal combustion engine with a variable cylinder mechanism of the present invention as defined in claim 3, in the structure of claim 1 or 2, the variable cylinder control means causes the engine output torque during the cylinder deactivation mode operation. And the engine output torque during the all-cylinder mode operation is substantially equal to the reference engine load that is larger than the reference engine load, switching between the cylinder deactivation mode operation and the all-cylinder mode operation is performed. With the configuration that is set to, the mode switching shock can be reduced while the mode switching setting that tends to cause a large mode switching shock with the characteristics of the original engine is performed, and the drive feeling can be improved. is there.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a control system of an internal combustion engine with a variable cylinder mechanism as a first embodiment of the present invention.

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

FIG. 4 is a characteristic diagram of the output torque of the engine for explaining the control and effect of the internal combustion engine with the variable cylinder mechanism as the first embodiment of the present invention.

FIG. 5 is a characteristic diagram of the output torque of the engine for explaining the control and the effect of the internal combustion engine with the variable cylinder mechanism as the first embodiment of the present invention.

FIG. 6 is a flowchart showing a control procedure of the internal combustion engine with a variable cylinder mechanism as the first embodiment of the present invention.

FIG. 7 is a time chart for explaining effects of the internal combustion engine with a variable cylinder mechanism as the first embodiment of the present invention.

FIG. 8 is a schematic block diagram showing a control system of an internal combustion engine with a variable cylinder mechanism as a second embodiment of the present invention.

FIG. 9 is a flowchart showing a control procedure of an internal combustion engine with a variable cylinder mechanism as a second embodiment of the present invention.

FIG. 10 is a characteristic diagram of the output torque of the engine for explaining the problems of the conventional example and 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 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 Rotation shaft of throttle valve 40 Valve drive actuator 44 Fuel supply source 46 O ₂ sensor 48 Variable cylinder mechanism 50 Cylinder / all cylinder switching mechanism 51, 52 Rocker arm 51A, 52A Fitting holes 53, 54 Hydraulic piston 53A 54A Oil Chamber 55 T Lever 56, 57 Return Spring 60 Hydraulic Pump 61 Accumulator 66 Idle Speed Controller (ISC) 70 Mode Control Means (Variable Cylinder Control Means) 70A Mode Judgment Unit 70B Mode Setting Unit 76 Power Generation Control Means 76A Power Generation Cut Judging Means 76B Power generation / power generation cut control means 78 Engine driven generator (alternator) 80 Mode setting means 81 Electromagnetic valve control means 82 ISC control means 83 Fuel injection control means 84 Ignition timing control means 85 Power generation control means 91 Electromagnetic valve (OCV) 92 Bypass type idle speed controller (IS
C) 93 fuel injection means 94 ignition means (ignition plug) 95 generator 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)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Nakai 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation

Claims (3)

[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 mechanism includes variable cylinder control means for controlling the operation of the variable cylinder mechanism so as to operate in the all cylinder mode, and power generation control means for controlling the operation of a generator driven by the internal combustion engine. An internal combustion engine with a variable cylinder mechanism, wherein the power generation control means is set to perform control to stop or suppress power generation by the generator during the cylinder cutoff mode operation. 2. The power generation control means is set so as to perform control to stop or suppress power generation by the generator during the cylinder cutoff mode operation in the high speed rotation region of the internal combustion engine. An internal combustion engine with a variable cylinder mechanism according to claim 1. 3. The variable cylinder control means controls the engine output torque in the cylinder deactivation mode operation and the engine output torque in the all cylinder mode operation to be substantially equal to each other, with respect to the reference engine load. 3. The internal combustion engine with a variable cylinder mechanism according to claim 1, wherein the internal combustion engine with variable cylinder mechanism is set to switch between the cylinder deactivation mode operation and the all cylinder mode operation with a large engine load.