JP2004324572A - Control unit of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control unit of an internal combustion engine capable of suppressing torque fluctuation accompanying change of the number of operating cylinders in the internal combustion engine in which the number of operating cylinders can be changed according to its operation state. <P>SOLUTION: The electronic control unit (ECU) changes the number of operating cylinders according to the operation state of the engine (steps 115, 120, 130). A phase with respect to rotation of an output axis in a series of combustion strokes in the operating cylinders is changed according to the change of the number of operating cylinders by controlling a phase variable mechanism (steps 120, 125). With regard to this phase changing, a difference between a phase in a predetermined operating cylinder and a phase in another operating cylinder is considered to be a phase interval. The phase is changed so as to make the phase intervals approximately equal among the operating cylinders. For example, the phase is changed so as to make the phase interval larger when the number of operating cylinders decreases and smaller when the number of operating cylinders increases. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an internal combustion engine, and more particularly to a control device suitable for being applied to an internal combustion engine that performs a reduced cylinder operation in which a specific cylinder is deactivated according to an operation state of the engine.
[0002]
[Prior art]
Conventionally, a plurality of cylinders are provided, and a series of combustion strokes such as an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke are performed for each cylinder in accordance with the reciprocation of a piston in each cylinder, and output. An internal combustion engine in which a shaft is rotated is general.
[0003]
As a technique for controlling such an internal combustion engine, there is a technique for changing the number of operating cylinders, which are cylinders in which combustion is performed, according to an engine operating state (for example, see Patent Document 1). This technique is called so-called reduced cylinder operation control, in which fuel supply to a specific cylinder is stopped during low-speed running, light-load running, etc., and the internal combustion engine is operated only with the remaining cylinders. The aim is to improve fuel efficiency by reducing the amount.
[0004]
Further, in Patent Document 1, when the piston is located near the top dead center in the exhaust stroke of the idle cylinder, both the intake valve and the exhaust valve are closed, so that the minimum gas is sealed in the cylinder. ing. Due to this encapsulation, expansion and contraction of 1 atm or less are repeated in the idle cylinder with the reciprocating motion of the piston, thereby reducing the stroke loss and cooling loss. In addition, since no air is sucked and discharged in the idle cylinder, loss due to air viscosity, inertia, and the like is eliminated.
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 5-42652
[0006]
[Problems to be solved by the invention]
However, in Patent Document 1 described above, although the fuel loss can be improved by reducing the friction loss in the deactivated cylinder, the explosion intervals between the operating cylinders become uneven due to the reduced number of cylinders, and the fluctuation of the output torque of the internal combustion engine increases. I do. As a result, inconveniences such as an increase in vibration and noise of the internal combustion engine may occur. Such a problem (torque fluctuation and increase in vibration and noise due to the torque fluctuation) can occur not only in Patent Document 1 but also in an internal combustion engine in which conventional reduced-cylinder operation control is performed.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an internal combustion engine in which the number of operating cylinders is changed according to the operating state of the internal combustion engine. An object of the present invention is to provide a control device for an internal combustion engine that can suppress fluctuation.
[0008]
[Means for Solving the Problems]
Hereinafter, the means for achieving the above object and the effects thereof will be described.
According to the first aspect of the present invention, there is provided an internal combustion engine in which a plurality of cylinders are provided, and a series of combustion strokes are performed for each cylinder in accordance with reciprocation of a piston in each cylinder, and an output shaft is rotated. Variable cylinder control means for changing the number of operating cylinders according to the operating state of the internal combustion engine, and a variable phase mechanism for changing the phase of the series of strokes in the operating cylinder with respect to rotation of the output shaft. And phase control means for variably controlling the phase by the phase variable mechanism in accordance with a change in the number of operating cylinders by the variable cylinder control means.
[0009]
According to the above configuration, the number of operating cylinders is changed by the variable cylinder control means according to the operating state of the internal combustion engine. By this change, for example, when a specific cylinder is stopped and the number of operating cylinders is reduced, the substantial displacement of the internal combustion engine is temporarily reduced, and the fuel efficiency is improved. On the other hand, when the variable phase mechanism is controlled by the phase control means, the phase of the series of combustion strokes with respect to the rotation of the output shaft is changed, and the explosion interval between the working cylinders changes accordingly. Therefore, by changing the phase so as to provide an appropriate explosion interval in accordance with the change in the number of operating cylinders, it is possible to reduce torque fluctuations and thereby reduce vibration and noise.
[0010]
According to a second aspect of the present invention, in the first aspect of the invention, the phase control means sets a difference between a phase in a predetermined working cylinder and a phase in another working cylinder as a phase interval, Are changed before and after the phase change.
[0011]
Here, in general, if the explosion intervals between the working cylinders are not uniform, the fluctuation of the output torque tends to increase, and the vibration and noise tend to increase. In this regard, according to the second aspect of the present invention, the phase interval is changed to a different value when the phase is changed. With this change, the explosion interval between the working cylinders changes. Therefore, it is possible to reduce the torque fluctuation by changing the phase interval so that an appropriate explosion interval is obtained.
[0012]
According to a third aspect of the present invention, in the second aspect of the present invention, the phase control unit increases the phase interval in accordance with control by the variable cylinder control unit to reduce the number of operating cylinders. And
[0013]
According to the above configuration, when the number of active cylinders is reduced by the variable cylinder control means, no explosion is performed on the idle cylinders, so that the explosion interval between the active cylinders is different from that before the change in the number of active cylinders. Under the uniform explosion interval, the explosion interval after the change in the number of operating cylinders becomes larger than before the change. In this regard, in the invention according to the third aspect, the phase interval is increased according to the decrease in the number of operating cylinders. Therefore, by increasing the phase interval in this way, it is possible to make the explosion intervals substantially uniform for the reduced operating cylinders.
[0014]
According to a fourth aspect of the present invention, in the second or third aspect of the invention, the phase control means reduces the phase interval in accordance with control for increasing the number of operating cylinders by the variable cylinder control means. And
[0015]
According to the above configuration, when the number of working cylinders is increased by the variable cylinder control means, the explosion is also performed on the cylinders that have been suspended until then, so the explosion interval between the working cylinders is different from that before the change in the number of working cylinders. Come. Under the same explosion interval, the explosion interval after the change in the number of operating cylinders becomes smaller than before the change. In this regard, in the invention according to claim 4, the phase interval is reduced as the number of operating cylinders increases. Therefore, by reducing the phase interval in this way, it is possible to make the explosion intervals approximately equal for the increased number of operating cylinders.
[0016]
In the invention described in claim 5, in the invention described in any one of claims 1 to 4, the phase control unit changes the phase interval between the operating cylinders according to a change in the number of operating cylinders by the variable cylinder control unit. It is assumed that the phase is changed so as to be substantially equal.
[0017]
According to the above configuration, when the number of working cylinders is changed by the variable cylinder control means, the explosion interval between the working cylinders becomes different from that before the change in the number of working cylinders in accordance with the change. On the other hand, in the invention described in claim 5, the phase is changed such that the phase interval is substantially equal between the operating cylinders according to the change in the number of operating cylinders. Due to this phase change, after the number of operating cylinders is changed, explosions are performed at substantially equal intervals, and it is possible to suppress torque fluctuations and effectively reduce vibration and noise.
[0018]
In the invention described in claim 6, in the invention described in any one of claims 1 to 5, the variable cylinder control means sets all the cylinders as active cylinders when the internal combustion engine is started, and at least two active cylinders. And the phase control means, when the internal combustion engine is stopped, wherein the strokes of all the combustion target cylinders allow the output shaft to rotate when the engine is started. It is assumed that the phase is changed as follows.
[0019]
According to the above configuration, when the phase is changed by the phase control unit when the internal combustion engine is stopped, the strokes of all (at least two) cylinders to be burned make the output shaft rotatable at the next engine start. To be. Then, when the internal combustion engine is started by the variable cylinder control means, when the air-fuel mixture is ignited substantially simultaneously for all the combustion target cylinders stopped in the above-described stroke, explosion and combustion are performed in these combustion target cylinders substantially simultaneously. The piston is pushed down, and the output shaft is driven to rotate. A large torque is required to rotate the output shaft without inertia force, but since combustion is performed substantially simultaneously in a plurality of combustion target cylinders that are stopped during the process of enabling the output shaft to rotate, a large torque is required. The output shaft is driven to rotate. Therefore, rotation of the output shaft for starting the engine is possible without using a starter for starting the engine.
[0020]
In the invention described in claim 7, in the invention described in claim 6, it is assumed that the stroke that enables the output shaft to rotate is the first half of the expansion stroke.
According to the above configuration, the volume of the combustion chamber is reduced with the engine valve closed, and the air in the combustion chamber is compressed in the first half of the expansion stroke in which the piston is in the process of descending. Therefore, when the internal combustion engine is started, when fuel is injected and ignited in all the cylinders to be burned, explosion and combustion are reliably performed, the corresponding piston is pushed down, and the output shaft is driven to rotate.
[0021]
In the invention described in claim 8, in the invention described in claim 6 or 7, the phase control means sets the phase changed at the time of the engine stop to a predetermined rotation speed of the output shaft at the time of the engine start. The variable cylinder control means keeps the combustion until substantially exceeding the predetermined value at the time of starting the engine until the rotation speed of the output shaft exceeds the predetermined value.
[0022]
According to the above configuration, when the internal combustion engine is started, the substantially simultaneous combustion of all the combustion target cylinders is continued, so that the rotation speed of the output shaft is increased. This type of combustion is continued until the rotation speed of the output shaft exceeds a predetermined value. When the rotation speed of the output shaft becomes equal to or higher than a predetermined value, the combustion in the above-described mode is stopped and the output shaft is rotated by inertia even if combustion is performed for each cylinder. Variable cylinder control and phase control according to the number of operating cylinders can be performed.
[0023]
According to a ninth aspect of the present invention, in the invention according to the sixth or seventh aspect, the phase control means converts the phase changed when the engine is stopped to the number of times of combustion or the number of times of combustion per hour when the engine is started. Is maintained until a predetermined value is exceeded, and the variable cylinder control means continues the phase changed when the engine is stopped until the number of combustions or the number of combustions per time exceeds the predetermined value. I do.
[0024]
According to the above configuration, when the internal combustion engine is started, the substantially simultaneous combustion of all the combustion target cylinders is continued, so that the rotation speed of the output shaft is increased. The combustion in this mode is continued until the number of times of combustion or the number of times of combustion per hour exceeds a predetermined value. When the above condition is satisfied, the combustion in the above-described mode is stopped, and the output is rotated by inertia even if the combustion is performed one by one. Therefore, the variable cylinder control according to the engine operating state, and Phase control according to the number of operating cylinders becomes possible.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a vehicle includes a gasoline engine (hereinafter simply referred to as a four-cylinder of a first cylinder # 1, a second cylinder # 2, a third cylinder # 3, and a fourth cylinder # 4) having a plurality of cylinders. An engine 11 is mounted as an internal combustion engine. A piston 12 is accommodated in each of the cylinders # 1 to # 4 so as to be able to reciprocate. A combustion chamber 13 for burning a mixture of fuel and air is provided on the head side (upper side in FIG. 1) of the piston 12 in each of the cylinders # 1 to # 4. The piston 12 is lowered by receiving a pressure (combustion pressure) generated by combustion in the combustion chamber 13. A common output shaft 14 is arranged near the lower part of each cylinder # 1 to # 4. The output shaft 14 corresponds to a crankshaft in a general crank structure, and is rotatably supported on an engine body such as a cylinder block and a crankcase by a bearing 15 (see FIG. 2).
[0026]
The engine 11 is provided with the following movement direction conversion mechanisms A for each of the cylinders # 1 to # 4 in order to convert the movement of each piston 12 into the rotation movement of the output shaft 14. As shown in FIGS. 2 and 3, one end (a lower end in FIG. 2, a right end in FIG. 3) of a link 17 is supported on the output shaft 14 so as to be relatively rotatable. The link 17 can swing up and down with the output shaft 14 as a fulcrum. The link 17 and the piston 12 are connected by a connecting member 18. The connecting member 18 corresponds to a connecting rod in a general crank structure, is connected to the piston 12 by a pin 19 at an upper end, and is connected to a distal end of the link 17 by a pin 21 at a lower end (the upper end in FIG. (Left end in FIG. 3).
[0027]
On the other hand, in the engine body, crank members 23 to 26 for each of cylinders # 1 to # 4 are rotatably supported by bearings 22. Each of the crank members 23 to 26 has a crank pin 23a to 26a at a position eccentric from the rotation center C. Each of the crank pins 23a to 26a revolves around the rotation center C as the corresponding crank members 23 to 26 rotate. Each of the crank pins 23 a to 26 a is movably engaged in a slide groove 27 provided in the corresponding link 17. The slide groove 27 absorbs a change in the interval between the output shaft 14 and the crank pins 23a to 26a due to the rotation of the crank members 23 to 26.
[0028]
Electromagnetic clutches 28 are provided between the output shaft 14 and each link 17 in order to transmit the swing of the link 17 to the output shaft 14 or cut off the transmission. Each electromagnetic clutch 28, when energized, connects the corresponding link 17 and output shaft 14 so as to be integrally rotatable, enabling power transmission between the two. When the energization is stopped, the electromagnetic clutches 28 release the connection and cut off the transmission of power between the links 17 and the output shaft 14.
[0029]
Each of the electromagnetic clutches 28 is energized during an arbitrary period during a period in which the piston 12 descends and the link 17 swings downward. For example, when the swing of the link 17 is going to be faster than the rotation of the output shaft 14, the electromagnetic clutch 28 is energized during the period in which the piston 12 descends due to the combustion pressure generated due to the combustion of the air-fuel mixture. On the other hand, the electromagnetic clutches 28 are not energized when the piston 12 moves up and the link 17 swings upward. This is to prevent the rotation in the direction opposite to the direction when the piston is lowered from being transmitted to the output shaft 14.
[0030]
As shown in FIG. 1, each cylinder # 1 to # 4 is connected to an intake passage 31 for guiding air outside the engine 11 to the combustion chamber 13. An exhaust passage 32 for guiding exhaust generated in the combustion chamber 13 to the outside of the engine 11 is connected to each of the cylinders # 1 to # 4. In the engine 11, as engine valves, an intake valve 33 that opens and closes between the intake passage 31 and the combustion chamber 13 and an exhaust valve 34 that opens and closes between the exhaust passage 32 and the combustion chamber 13 are reciprocally provided. . In this embodiment, an electromagnetically driven valve is employed as a valve operating mechanism for driving the intake and exhaust valves 33 and 34. In this electromagnetically driven valve, when the solenoids 33a and 34a are energized, the intake and exhaust valves 33 and 34 reciprocate to open and close. The opening and closing timings of the intake and exhaust valves 33 and 34 can be changed by controlling the timing of energizing the solenoids 33a and 34a.
[0031]
A throttle valve 35 is provided rotatably in the middle of the intake passage 31. An actuator 36 such as a motor is drivingly connected to the throttle valve 35. The amount of air flowing through the intake passage 31 changes according to the rotation angle (throttle opening) of the throttle valve 35. Note that the throttle opening is adjusted by the ECU 55 (which will be described later) controlling the actuator 36 in accordance with the amount of depression of the accelerator pedal 37 operated by the driver. The amount of the air is also adjusted by controlling the lift of the electromagnetically driven valve.
[0032]
The engine 11 is provided with an electromagnetic fuel injection valve 38 corresponding to each of the cylinders # 1 to # 4. Each fuel injection valve 38 is opened and closed to inject fuel into the corresponding cylinder # 1 to # 4. The injected fuel mixes with the intake air taken into each combustion chamber 13 through the intake passage 31 to form an air-fuel mixture.
[0033]
The engine 11 is provided with spark plugs 39 corresponding to the cylinders # 1 to # 4. An igniter 41 is connected to each ignition plug 39 via an ignition coil 42. The igniter 41 interrupts the primary current of the ignition coil 42 based on the ignition signal. Due to this interruption, a high voltage is generated in the secondary coil of the ignition coil 42, and the ignition plug 39 is ignited. Then, the air-fuel mixture is ignited by the spark discharge accompanying the ignition of the ignition plug 39 and burns. The piston 12 is pushed down by the high-temperature and high-pressure combustion gas generated at this time.
[0034]
In each movement direction conversion mechanism A, the downward movement of the piston 12 is transmitted to the link 17 via the connecting member 18, and the link 17 swings downward about the output shaft 14 as a fulcrum. With this swing, the crank members 23 to 26 rotate in a predetermined direction (for example, clockwise), and the crank pins 23a to 26a revolve around the rotation center C. When the piston 12 reaches the vicinity of the bottom dead center, the crank pins 23a to 26a of the crank members 23 to 26 are located below the rotation center C. The crank members 23 to 26 continue to rotate due to inertia even after the piston 12 reaches the bottom dead center. This rotation is transmitted to the link 17 via the crank pins 23a to 26a, and the link 17 swings upward with the output shaft 14 as a fulcrum. As described above, the link 17 swings upward with the output shaft 14 as a fulcrum by receiving a force from the crank members 23 to 26. This swing is transmitted to the piston 12 via the connecting member 18, and the piston 12 rises. In this way, the piston 12 that has fallen due to the combustion pressure rises due to the revolution of the crank pins 23a to 26a. Accordingly, the piston 12 reciprocates continuously, and the link 17 continuously swings up and down.
[0035]
In the process in which the swing of the link 17 is transmitted to the output shaft 14, the swing is restrained in one direction by the electromagnetic clutch 28. That is, as described above, when the electromagnetic clutch 28 is energized during an arbitrary period of the period in which the link 17 swings downward, the output shaft 14 rotates integrally with the link 17. Accordingly, the output shaft 14 rotates by one predetermined angle (less than 360 degrees) in one direction (clockwise) while the piston 12 makes one reciprocation. Thus, the combustion pressure accompanying the combustion is extracted as the rotational force (output torque) of the output shaft 14.
[0036]
While the output shaft 14 makes two rotations and the pistons 12 make two reciprocations, the engine 11 performs a series of four combustion operations, namely, an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each of the cylinders # 1 to # 4. This is a so-called four-cycle engine that performs two strokes (cycles). The intake stroke and the expansion stroke are performed when the piston 12 descends, and the compression stroke and the exhaust stroke are performed when the piston 12 rises.
[0037]
In the intake stroke, the exhaust valve 34 is closed, the intake valve 33 is opened, and fuel is injected from the fuel injection valve 38 into the combustion chamber 13. The injected fuel mixes with the air sucked into the combustion chamber 13 due to a decrease in the pressure (in-cylinder pressure) in the combustion chamber 13 due to the lowering of the piston 12. In the compression stroke, the intake valve 33 in addition to the exhaust valve 34 is closed. For this reason, the pressure in the combustion chamber 13 rises with the rise of the piston 12, and the pressure and temperature of the air-fuel mixture rise.
[0038]
In the expansion stroke, ignition is performed by the ignition plug 39 with both the intake and exhaust valves 33 and 34 closed, and the mixture is ignited and exploded. The piston 12 is pushed down by the downward force accompanying this explosion, and a rotational force is applied to the output shaft 14 via the connecting member 18 and the link 17. In the exhaust stroke, the exhaust valve 34 is opened. Therefore, the exhaust gas generated in the combustion chamber 13 is discharged to the exhaust passage 32 as the piston 12 rises.
[0039]
Here, a cylinder in which a series of combustion strokes is performed as described above is referred to as a working cylinder. On the other hand, in the engine 11 of the present embodiment, the specific cylinder may be stopped depending on the operation state. The pause here means that at least the fuel injection is stopped among the fuel injection by opening the fuel injection valve 38, the ignition by the spark plug 39, and the opening of the intake / exhaust valves 33 and 34, and the explosion of the air-fuel mixture The combustion is temporarily stopped.
[0040]
A series of strokes for the combustion described above is performed at different timings (rotation angles of the output shaft 14) for each of the cylinders # 1 to # 4 according to the number of operating cylinders. FIG. 4A shows the relationship between the rotation angle of the output shaft 14 and the stroke when all of the cylinders # 1 to # 4 (four cylinders) are operated during normal operation. As can be seen from this figure, the same stroke is shifted in the order of the first cylinder # 1 → the third cylinder # 3 → the fourth cylinder # 4 → the second cylinder # 2 by a predetermined rotation angle (180 °). Done. Note that this order is merely an example and can be changed as appropriate. FIG. 4B shows a relationship between the rotation angle and the stroke of the output shaft 14 when all of the cylinders # 1 to # 4 (four cylinders) are operated when the engine is started. As can be seen from this figure, for example, each stroke of the third cylinder # 3 is performed in synchronization with the first cylinder # 1. The two cylinders to be synchronized are the cylinders that are originally scheduled to burn first and second when the engine is started. The other cylinders (# 4, # 2) are the same as in the normal operation described above (FIG. 4A).
[0041]
FIG. 5 shows the rotation angle of the output shaft 14 when one predetermined cylinder (here, # 2) is stopped and the remaining three cylinders (# 1, # 3, # 4) are operated. It shows the relationship with the process. As can be seen from this figure, the same stroke is performed in the order of the first cylinder # 1 → the third cylinder # 3 → the fourth cylinder # 4 with a predetermined rotation angle (240 °) being shifted.
[0042]
FIG. 6 shows the rotation angle and stroke of the output shaft 14 when two predetermined cylinders (here, # 2 and # 3) are stopped and the remaining two cylinders (# 1 and # 4) are operated. The relationship is shown. As can be seen from this figure, the same stroke is performed in the order of the first cylinder # 1 → the fourth cylinder # 4 with a predetermined rotation angle (360 °) shifted.
[0043]
Further, in the engine 11 of the present embodiment, it is possible to change the crank angle phase, which is the phase of the crank pins 23a to 26a with respect to the rotation of the output shaft 14, by making the energization timing of each electromagnetic clutch 28 variable. . For example, during a period in which the piston 12 descends due to the combustion pressure generated due to the combustion of the air-fuel mixture, the energization timing of the electromagnetic clutch 28 is delayed as compared with the normal time. In this case, since the combustion pressure is consumed only for pushing down the piston 12, that is, not consumed for rotating the output shaft 14, the piston 12 descends at a correspondingly high speed, and the crank angle phase advances. Be horned. Through this change, the phase with respect to the rotation of the output shaft 14 in the above-described series of combustion strokes (the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke) is changed. If a difference between a phase in a predetermined working cylinder and a phase in another working cylinder is defined as a phase interval, the phase interval differs before and after the phase change.
[0044]
As described above, in the present embodiment, the movement direction conversion mechanism A provided with the electromagnetic clutch 28 is used as a phase for changing the phase (crank angle phase) with respect to the rotation of the output shaft 14 in a series of strokes for combustion in the working cylinder. Used as a variable mechanism.
[0045]
By changing the energization timing, for example, based on the crank angle phases of the crank pins 24a and 25a corresponding to the cylinders # 2 and # 3, the crank angles of the crank pins 23a and 26a corresponding to the cylinders # 1 and # 4 The phase is changed as follows according to the number of operating cylinders.
[0046]
When the number of operating cylinders is “2”, as shown in FIGS. 7A and 7B, the crank angle phases of the crank pins 23a and 26a corresponding to the cylinders # 1 and # 4 are The crank pins 24a and 25a corresponding to # 2 and # 3 are shifted by 180 degrees in the rotation direction (for example, clockwise) with respect to the crank angle phase. When the number of operating cylinders is "4", it is basically the same as the case where the number of operating cylinders is "2". However, when the engine 11 is stopped, the crankpin corresponding to the combination that is in the vicinity of the expansion stroke immediately before the stop is selected from the combination of the two cylinders in the explosion order in preparation for the next start. The crank angle phases of 23a to 26a are made the same. For example, when these cylinders are the cylinders # 1 and # 3, as shown in FIGS. 8A and 8B, the crank angle phase of the crank pin 25a corresponding to the cylinder # 3 becomes the cylinder # 1. And the crank angle phase of the crank pin 23a corresponding to In this case, the crank angle phase of the crank pin 25a corresponding to the cylinder # 3 is the same as the crank angle phase of the crank pins 23a and 26a corresponding to the cylinders # 1 and # 4. It is shifted by 180 ° in the rotation direction (clockwise direction) with respect to the crank angle phase.
[0047]
When the number of operating cylinders is "3", as shown in FIGS. 9A and 9B, the crank angle phase of the crank pin 23a corresponding to the cylinder # 1 is changed to the cylinder # 2, # 3. Are shifted by 120 ° in the rotation direction with respect to the crank angle phases of the crank pins 24a and 25a corresponding to the above. Further, the crank angle phase of crank pin 26a corresponding to cylinder # 4 is shifted by 240 ° in the rotational direction with respect to the crank angle phase of crank pins 24a and 25a corresponding to cylinders # 2 and # 3. As a result, the angle formed by the crank pins 23a to 26a with respect to the rotation center C decreases from 180 ° when the number of operating cylinders is “2” or “4” to 120 °.
[0048]
By the way, a battery (not shown) is mounted on a vehicle as a power source of various electric devices. The various electric devices include an ECU 55 described later. The supply and stop of electric power from the battery to various electric devices are performed in response to the operation of an ignition switch (SW) 44 shown in FIG. 1 by the driver. As is well known, the ignition switch 44 is movable between an off position and an on position, and between the on position and a start position. Basically, electric power is supplied to various electric devices while the ignition switch 44 is operated to the ON position. In the vehicle of the present embodiment, a starter used for a general engine as a starting device is not provided.
[0049]
The vehicle is provided with various sensors other than the above-described ignition switch 44 in order to detect the operating state of the engine 11. For example, as shown in FIGS. 1 and 2, a rotation angle sensor 45 that generates a pulse signal every time the output shaft 14 rotates by a predetermined angle is provided near the output shaft 14. The signal from the rotation angle sensor 45 is used for calculating the rotation angle of the output shaft 14 and the engine rotation speed NE which is the rotation speed of the output shaft 14 per unit time. In the vicinity of each of the crank members 23 to 26, there are provided crank angle sensors 46 to 49 which generate a pulse-like signal each time they rotate by a predetermined angle.
[0050]
As shown in FIG. 1, an intake pressure sensor 50 for detecting the pressure (intake pressure) of intake air is provided downstream of the throttle valve 35 in the intake passage 31. An accelerator sensor 51 is provided near the accelerator pedal 37 to detect the amount of depression of the accelerator pedal 37 by the driver (accelerator opening). In the vicinity of the throttle valve 35, a throttle sensor 52 for detecting a throttle opening is provided.
[0051]
An electronic control unit (ECU) mainly composed of a microcomputer for controlling various parts of the vehicle including the engine 11 based on the detection values of the ignition switch 44, various sensors 45 to 52, and the like. 55 are provided. In the ECU 55, a central processing unit (CPU) performs arithmetic processing according to a control program and initial data stored in a read-only memory (ROM), and performs various controls based on the arithmetic results. The calculation result by the CPU is temporarily stored in a random access memory (RAM).
[0052]
Next, the operation of the present embodiment configured as described above will be described.
11 and 12 show a routine for controlling the operation of the engine 11 among the processes executed by the ECU 55, and are executed at a predetermined timing, for example, at regular intervals. The engine control routine includes control at the time of starting the engine (start control) performed in steps 100 to 110, control during normal operation (normal control) performed in steps 115 to 140, and engine control performed in steps 145 to 160. It is roughly divided into stop control (stop control).
[0053]
In the start control, all the cylinders # 1 to # 4 are set as operating cylinders when the engine is started. In addition, two working cylinders in a continuous explosion order are set as combustion target cylinders that perform combustion substantially simultaneously. Then, combustion is performed at a timing corresponding to the crank angle phase changed when the engine was stopped last time. In the normal control, the number of operating cylinders is changed according to the operation state of the engine 11. Also, the phase of the series of strokes for combustion in the working cylinder with respect to the rotation of the output shaft 14 is changed according to the change in the number of working cylinders. In the stop control, when the engine 11 is stopped, the crank angle phase is changed so that the strokes of all (two in this case) the combustion target cylinders become the strokes that enable the output shaft 14 to rotate at the next engine start. You. Next, the contents of each control will be described.
[0054]
In the start control, the ECU 55 first determines whether or not an engine start condition is satisfied in step 100 of FIG. Here, the engine start condition includes, for example, “the ignition switch 44 has been operated to the ON position”. If this determination condition is satisfied, the routine proceeds to step 105, where fuel injection and ignition are performed at a timing according to the crank angle phase at the time of the previous engine stop. In the crank angle phase when the engine is stopped, the cylinders in which the first and second explosions and combustions are performed when the engine 11 is started this time are both stopped in the first half of the expansion stroke. Then, fuel injection is performed substantially simultaneously for these cylinders, and ignition is performed substantially simultaneously. In the first half of the expansion stroke, the volume of the combustion chamber 13 is reduced in a state where the intake and exhaust valves 33 and 34 are both closed, and the air in the combustion chamber 13 is discharged immediately after the piston 12 starts to descend. Compressed. Therefore, when fuel is injected and ignited in both cylinders, explosion and combustion occur, the corresponding piston 12 descends, and the output shaft 14 is driven to rotate.
[0055]
At this time, since the explosion and combustion are performed almost simultaneously by the fuel injection and the ignition for the two cylinders and the pistons 12 are pushed down, the output shaft 14 has a higher output than the case where the explosion and combustion are performed in one cylinder. A large force is transmitted, and the output shaft 14 rotates. A large torque is required to rotate the output shaft 14 having no inertia force, but since the combustion is performed substantially simultaneously in the two cylinders, the output shaft 14 is rotated with a large torque. The rotation speed of the output shaft 14 (engine rotation speed NE) is increased by continuously performing such combustion in the two cylinders.
[0056]
Next, at step 110, it is determined whether or not the engine speed NE obtained from the signal of the rotation angle sensor 45 is higher than a predetermined value α. Here, the predetermined value α is set to a value approximately equal to or slightly larger than the minimum value of the engine rotation speed required for the engine 11 to continue operating. If the determination condition of step 110 is not satisfied, the process returns to step 105 described above. Thus, the substantially simultaneous combustion in the two cylinders is continued until the engine speed NE exceeds the predetermined value α. On the other hand, if the determination condition of step 110 is satisfied, it is considered that the output shaft 14 will rotate due to inertia even if the combustion in the above-described mode is stopped and combustion is performed one cylinder at a time. After the control, the process proceeds to the normal control. If the determination condition of step 100 is not satisfied, the process shifts to the normal control without performing the processing of steps 105 and 110.
[0057]
In the normal control, first, in step 115, the ECU 55 calculates the target number of operating cylinders based on the operating state at that time. In this calculation, for example, a map shown in FIG. 10 is referred to. In this map, the operating range of the engine 11 represented by the engine rotational speed NE and the engine load is a range in which all the cylinders (four cylinders) are driven, a range in which the three cylinders are driven, and a range in which the two cylinders are driven. Is divided into Then, the operating range to which the engine rotational speed NE and the engine load belong at that time is determined from the map. Note that the engine load is calculated based on, for example, parameters related to the intake air amount of the engine 11 (for example, throttle opening, accelerator opening, intake pressure, and the like).
[0058]
Next, in step 120, it is determined whether the target number of operating cylinders has been changed. That is, it is determined whether or not the current target number of operating cylinders obtained in step 115 is different from the target number of operating cylinders obtained in the previous control cycle. If this determination condition is satisfied, a process of changing the crank angle phase is performed in step 125. In this change process, for example, a target crank angle corresponding to the target number of operating cylinders in step 115 is calculated. For example, the target crank angle phase of the crank pins 24a and 25a corresponding to the cylinders # 2 and # 3 is used as a reference. As shown in FIGS. 7A and 7B, when the target number of operating cylinders is “4” or “2”, the target crank of the crank pins 23a and 26a corresponding to the cylinders # 1 and # 4. As the angular phase, a value obtained by delaying or advancing by 180 ° with respect to the target crank angle phase of the crank pins 24a and 25a corresponding to the cylinders # 2 and # 3 is calculated.
[0059]
When the target number of operating cylinders is “3”, as shown in FIGS. 9A and 9B, the target crank angle phase of the crank pin 23a corresponding to the cylinder # 1 is set to the cylinder # 2. , # 3, a value advanced by 120 ° with respect to the target crank angle phase of the crank pins 24a, 25a is calculated. Incidentally, the target crank angle phase of the crank pin 23a is a value delayed by 60 ° from the target crank angle phase when the above-mentioned target number of operating cylinders is “4” or “2”. A value obtained by advancing the target crank angle phase of the crank pins 24a and 25a corresponding to the cylinders # 2 and # 3 by 240 ° is calculated as the target crank angle phase of the crank pin 26a corresponding to the cylinder # 4. Incidentally, the target crank angle phase of the crank pin 26a is a value advanced by 60 ° with respect to the target crank angle phase when the above-mentioned target number of operating cylinders is "4" or "2". Then, power is supplied to the electromagnetic clutch 28 for each of the cylinders # 1 to # 4 so that the actual crank angle phase obtained based on the signals from the rotation angle sensor 45 and the crank angle sensors 46 to 49 matches the target crank angle phase. Control timing.
[0060]
Next, in step 130, fuel injection and ignition are performed at a timing corresponding to the crank angle phase changed in step 125. In the process of step 130, the fuel injection from the fuel injection valve 38, the ignition of the spark plug 39, and the driving (opening) of the intake and exhaust valves 33 and 34 are stopped, that is, deactivated, for the specific cylinder. Is also included. As described above, the cylinders to be deactivated are the second and third cylinders # 2 and # 3 when the target number of operating cylinders is "2" (see FIG. 6), and the target number of cylinders is "3". ", The second cylinder # 2 (see FIG. 5).
[0061]
Further, when the target number of operating cylinders is changed from "4" or "2" to "3", fuel injection and ignition are performed between the operating cylinders # 1, # 3, and # 4 in accordance with the change. The interval between the angles is changed from 180 ° shown in FIG. 4A or 360 ° shown in FIG. 6 to 240 ° shown in FIG.
[0062]
When the target number of operating cylinders is changed from “3” to “4” or “2”, the number of operating cylinders # 1 to # 4 or between the operating cylinders # 3 and # 4 is changed in accordance with the change. The interval at which fuel injection and ignition are performed is changed from 240 ° shown in FIG. 5 to 180 ° shown in FIG. 4A or 360 ° shown in FIG.
[0063]
In step 130, the timings of the valve opening periods of the intake and exhaust valves 33 and 34 are also changed.
On the other hand, if the determination condition in step 120 is not satisfied (the target number of operating cylinders is not changed), in step 135, the previous crank angle phase is held. In step 140, the fuel injection, ignition and intake / exhaust valves 33, 34 are driven at the same timing as the previous time.
[0064]
Then, after the processing of step 130 or 140 described above, the process proceeds to the stop control of FIG. As described above, in the normal control, the number of operating cylinders is changed according to the operating state of the engine 11. With this change, when the specific cylinders (# 2, # 3) are stopped and the number of operating cylinders is reduced, the substantial displacement of the engine 11 is temporarily reduced. On the other hand, when the number of working cylinders is changed, the phase of the series of combustion strokes with respect to the rotation of the output shaft 14 is changed, and the explosion interval between the working cylinders (# 1 to # 4) is changed accordingly. Changes.
[0065]
Here, in general, if the explosion intervals between the working cylinders # 1 to # 4 are not uniform, the generated torque fluctuates greatly, and vibration and noise tend to increase. In this regard, in the present embodiment, the phase interval is changed to a different value when the phase is changed. With this change, the explosion interval between the working cylinders # 1 to # 4 changes. Therefore, by changing the phase interval so as to provide an appropriate explosion interval, torque fluctuation is reduced.
[0066]
More specifically, when the number of operating cylinders is changed, the explosion interval between the operating cylinders # 1 to # 4 is different from that before the change in the number of operating cylinders. When the number of operating cylinders is reduced from, for example, “4” to “3”, no explosion is performed for the inactive cylinder (# 2). Therefore, the explosion interval between the operating cylinders # 1 to # 4 is changed before the change in the number of operating cylinders. And different. Under the uniform explosion interval, the explosion interval after the change in the number of operating cylinders becomes larger than before the change. Conversely, when the number of operating cylinders is increased from, for example, “3” to “4”, the cylinder (# 2) which has been stopped up to that time also explodes, and thus the number of operating cylinders # 1 to # 4 is increased. The explosion interval differs from before the change in the number of operating cylinders. Under the same explosion interval, the explosion interval after the change in the number of operating cylinders becomes smaller than before the change.
[0067]
On the other hand, in the present embodiment, the crank angle phase is changed in accordance with the change in the number of operating cylinders so that the phase interval becomes uniform among the operating cylinders # 1 to # 4. Due to this phase change, explosions are performed at substantially equal intervals after the number of operating cylinders is changed. For example, when the number of working cylinders is reduced, the phase interval is increased in accordance with the decrease, so that the explosion intervals of the reduced working cylinders (# 1, # 3, # 4) become substantially equal. . When the number of operating cylinders is increased, the phase interval is reduced in accordance with the increase, so that the explosion intervals of the increased operating cylinders # 1 to # 4 are substantially equal. Thus, even if the number of operating cylinders is increased or decreased, the explosion intervals are substantially equalized, so that torque fluctuation is suppressed.
[0068]
In the stop control, the ECU 55 first determines in step 145 whether a predetermined engine stop condition is satisfied. Here, the engine stop condition includes, for example, “the ignition switch 44 has been operated to the off position”. If the determination condition of step 145 is not satisfied, a series of processes of the engine control routine is temporarily ended to continue the normal control.
[0069]
On the other hand, if the determination condition in step 145 is satisfied, in step 150, the fuel injection and ignition for all the working cylinders # 1 to # 4 are stopped. Next, in step 155, the strokes of all (two in this case) combustion target cylinders, which are originally scheduled to be first and secondly burned at the next engine start, rotate the output shaft 14 at the time of the engine start. The crank angle phase is changed so that the stroke becomes possible (the first half of the expansion stroke). Specifically, the crank angle phase is changed so that the two combustion target cylinders stop in the first half of the expansion stroke. Then, in step 160, the energization of the solenoids 33a, 34a of the combustion target cylinder is stopped to close the intake / exhaust valves 33, 34, and then the engine control routine is ended once.
[0070]
As described above, when the crank angle phase is changed when the engine 11 is stopped, the stroke (expansion stroke) in which the output shaft 14 is rotatable in preparation for the next start of the engine (strokes of all (two) cylinders). First half).
[0071]
In the above-described engine control routine, the processing of steps 115, 120, and 130 corresponds to a variable cylinder control unit. Further, the processing of steps 120 and 125 corresponds to the phase control means.
[0072]
According to the embodiment described above, the following effects can be obtained.
(1) The number of operating cylinders is changed according to the operating state of the engine 11. With this change, the specific cylinders (# 2, # 3) are deactivated and the number of operating cylinders is reduced, so that the actual displacement of the engine 11 can be temporarily reduced to improve fuel efficiency.
[0073]
Further, by changing the crank angle phase of the crank pins 23a to 26a in accordance with the change in the number of operating cylinders, the phase with respect to the rotation of the output shaft 14 in a series of strokes for combustion in the operating cylinders is changed. Therefore, by changing the explosion interval between the working cylinders # 1 to # 4 and changing the phase so as to provide an appropriate explosion interval, it is possible to reduce torque fluctuations and thereby reduce vibration and noise. .
[0074]
(2) Related to the above (1), the difference between the phase in a predetermined operating cylinder and the phase in another operating cylinder is defined as a phase interval, and the phase interval is made different before and after the phase change, thereby enabling operation. The explosion interval between cylinders is changed. Therefore, by changing the phase interval so as to have an appropriate explosion interval, the torque fluctuation can be reduced, and the above-mentioned effect (1) can be further ensured.
[0075]
(3) According to the change in the number of operating cylinders, the phase is changed so that the phase interval is substantially equal between the operating cylinders # 1 to # 4. Therefore, when the number of working cylinders is changed, the explosion interval between the working cylinders is different from that before the change in the number of working cylinders in accordance with the change, but by changing the phase as described above, the number of working cylinders is changed. Later, the explosions are performed at substantially equal intervals, so that the torque fluctuation can be suppressed and the vibration and noise can be effectively reduced.
[0076]
(4) The phase interval is increased according to the control for reducing the number of operating cylinders. Therefore, when the number of operating cylinders is reduced from, for example, “4” to “3”, no explosion is performed for the inactive cylinder (# 2). Is larger than before the change. However, by increasing the phase interval as described above, it becomes possible to make the explosion intervals substantially uniform for the reduced operating cylinders.
[0077]
(5) The phase interval is reduced according to control for increasing the number of operating cylinders. Therefore, when the number of operating cylinders is increased from, for example, "3" to "4", the cylinder (# 2) which has been inactive up to that time also explodes, and under the uniform explosion interval, the number of operating cylinders increases. Explosion interval after change is smaller than before. However, by reducing the phase interval as described above, it is possible to make the explosion intervals substantially equal for the increased number of operating cylinders.
[0078]
(6) If it is attempted to change the number of operating cylinders without changing the crank angle phase, the number of operating cylinders that can equalize the explosion intervals between cylinders # 1 to # 4 is "4" and "4". 2 ". When the number of operating cylinders is “4”, the explosion and combustion are performed every 180 ° (see FIG. 4A), and when the number of operating cylinders is “2”, the explosion and combustion are performed every 360 °. (See FIG. 6). Therefore, if an attempt is made to improve fuel economy, which is the original purpose of reduced cylinder operation, while suppressing vibration, the number of operating cylinders will be switched between "4" and "2". However, when the number of operating cylinders is limited to “4” and “2”, the reduced cylinder operation region is accordingly limited. For example, in FIG. 10, a region indicated as a three-cylinder operation region is set as a four-cylinder operation region as indicated by a two-dot chain line. Therefore, the reduced cylinder operation is performed only by the two-cylinder operation. In this case, there is a limit in improving fuel efficiency.
[0079]
In this regard, in this embodiment, as described above, the crank angle phase is changed according to the change in the number of operating cylinders so that the explosion and combustion are performed at substantially equal angular intervals regardless of the number of operating cylinders. I have to. When the number of operating cylinders is “3”, explosion and combustion are performed every 240 ° (see FIG. 5). Therefore, in the variable cylinder control, the explosion intervals between the working cylinders # 1, # 3, and # 4 can be made substantially equal even if the number of working cylinders is set to "3". Therefore, as shown by the solid line in FIG. 10, a part of the four-cylinder operation region becomes a three-cylinder operation region, and the reduced-cylinder operation region is accordingly enlarged. Accordingly, it is possible to further reduce fuel consumption.
[0080]
(7) When the engine is started, all the cylinders # 1 to # 4 are set as working cylinders, and two working cylinders whose explosion order is continuous are set as combustion target cylinders that perform combustion almost simultaneously. Further, when the engine is stopped, the phases are changed so that the strokes of all the combustion target cylinders become the strokes that allow the output shaft 14 to rotate at the next engine start. Therefore, a large torque is required to rotate the output shaft 14 having no inertial force. However, as described above, combustion is performed almost simultaneously in all the combustion target cylinders that are stopped during the process of enabling the output shaft 14 to rotate. Therefore, the output shaft 14 can be rotated with a large torque. Therefore, the rotation of the output shaft 14 for starting the engine becomes possible without using a starter for starting the engine.
[0081]
(8) The “first half of the expansion stroke” is the stroke in which the output shaft 14 is rotatable in the above (7). In the first half of the expansion stroke, the volume of the combustion chamber 13 is reduced with the intake and exhaust valves 33 and 34 closed, and the piston 12 is in the process of descending, and the air in the combustion chamber 13 is compressed. . Therefore, when the engine 11 is started, by injecting and igniting fuel in these combustion target cylinders, explosion and combustion are performed, the corresponding piston 12 is lowered, and the output shaft 14 is reliably driven to rotate. it can.
[0082]
(9) The phase changed when the engine is stopped is held until the engine rotation speed NE exceeds a predetermined value α at the time of the next engine start. Further, the combustion performed substantially simultaneously in all the combustion target cylinders when the engine is started is continued until the engine speed NE exceeds the predetermined value α. Therefore, if the engine rotation speed NE increases and exceeds a predetermined value α due to this continuation, the output shaft 14 is rotated by inertia even if the combustion in the above-described mode is stopped and combustion is performed for each cylinder. Thus, variable cylinder control according to the operating state of the engine 11 and phase control according to the number of operating cylinders can be performed.
[0083]
Note that the present invention can be embodied in another embodiment described below.
-When the specific cylinder is stopped in the variable cylinder control, the fuel injection and the ignition to the same cylinder are stopped. At this time, the piston 12 may move in each of the cylinders # 1 to # 4 or may stop.
[0084]
-The target number of operating cylinders may be calculated by a method different from the above embodiment. For example, the engine load in the map of FIG. 10 described above may be changed to the required torque required for the engine 11. In this case, the required torque is obtained based on, for example, the vehicle speed, the shift position of the transmission, the throttle opening, and the like. In a vehicle equipped with a navigation system, road information from the system may be reflected in the calculation of the target number of operating cylinders. For example, on a downhill, a value smaller than “4” is calculated as the number of operating cylinders.
[0085]
In the three-cylinder operation in which the second cylinder # 2 and the third cylinder # 3 have the same crank angle phase, either one of the two cylinders # 2 and # 3 may be stopped during the three-cylinder operation. Alternatively, the cylinder to be deactivated may be switched when a predetermined condition is satisfied. For example, both cylinders # 2 and # 3 may be stopped alternately or at regular intervals.
[0086]
The present invention is not limited to four cylinders but is applicable to engines having a plurality of cylinders.
As the variable phase mechanism for changing the crank angle phase, a mechanism having a configuration different from that of the above embodiment may be used.
[0087]
For example, the electromagnetic clutch 28 in the movement direction conversion mechanism A of the embodiment is replaced with a one-way clutch that locks when the swing of the link 17 is going to be faster than the rotation of the output shaft 14. A motor generator, which is a motor having a power generation function, is drivingly connected to each of the crank members 23 to 26. Then, when retarding the crank angle phase, the motor generator is caused to function as a generator. In this case, since a part of the rotational energy of the crank members 23 to 26 is consumed for power generation, the rotation of the crank members 23 to 26 can be slowed. Conversely, when advancing the crank angle phase, the motor generator functions as an electric motor to rotate the crank members 23 to 26 at high speed.
[0088]
The number of combustion target cylinders that perform combustion substantially simultaneously when the engine 11 starts is not limited to two, and may be three or more. In this case, when the engine 11 is stopped, the crank angle phase is changed so that all of the three or more cylinders set as the combustion target cylinders stop in the first half of the expansion stroke.
[0089]
The process of step 110 in FIG. 11 may be “whether the number of combustions (number of ignitions) or the number of combustions per hour (number of ignitions) exceeds a predetermined value”. By doing so, the crank angle phase changed when the engine is stopped is held until the number of combustions or the number of combustions per time (combustion time interval) exceeds a predetermined value when the engine is started. Further, the crank angle phase changed when the engine is stopped is continued until the number of combustions or the number of combustions per time exceeds a predetermined value.
[0090]
Even if the processing content of step 110 is changed in this way, the same operation and effect as the processing before the change (whether the engine speed NE is higher than the predetermined value α) can be obtained. That is, when the engine 11 is started, the substantially simultaneous combustion of all the combustion target cylinders is continued, so that the rotation speed of the output shaft 14 increases. The combustion in this mode (a plurality of substantially simultaneous combustions when the engine is started) is continued until the number of combustions or the number of combustions per time exceeds a predetermined value. When the above condition is satisfied, the output of the engine is rotated by inertia even if the combustion in the above-described mode is stopped and the combustion is performed for each cylinder, so that the variable cylinder control according to the operating state of the engine 11 is performed. In addition, phase control according to the number of operating cylinders can be performed.
[0091]
The present invention is not limited to the four-cycle engine described above, but is also applicable to a so-called two-cycle engine in which a combustion cycle is performed once while the piston makes one reciprocation. In this case, in the combustion cycle, each piston rises to compress the air-fuel mixture, and each piston that receives the pressure (combustion pressure) generated by combustion in the combustion chamber descends to take out effective work. It consists of an explosion (expansion) process.
[0092]
The present invention is widely applicable to a device that changes the phase (crank angle phase) according to a change in the operating state of the engine. Here, the operating state is typically changed by the above-described control for changing the number of operating cylinders (variable cylinder control). In addition, the operating state also changes depending on the variable compression ratio, misfire, variable air-fuel ratio, various failures, variable ignition timing, variable valve timing, fuel injection timing, supercharging state, variable air-fuel ratio of only a specific cylinder, and the like.
[0093]
When the operating state changes, the output torque changes. Due to this change, the output torque of some cylinders may be lower than the output torque of other cylinders. For example, in the case of the variable cylinder control, the idle cylinder corresponds to the above-mentioned partial cylinder, and the working cylinder corresponds to the above-mentioned other cylinder. Therefore, from this viewpoint, it can be said that the variable cylinder control is a control for changing the output torque generated in each cylinder (output torque control). In this case, the change of the crank angle phase by the phase variable mechanism is controlled so that the crank angle phase corresponds to the output torque generated in each cylinder. In particular, when performing control to reduce the output torque by reducing the number of working cylinders, the phase variable mechanism is controlled so that the crank angle phase changes to the side where the explosion intervals of the working cylinders are equal. This can be realized, for example, by changing the phase of each operating cylinder so that the interval between the explosion timing of some cylinders and the explosion timing of other cylinders becomes narrow.
[0094]
-A cylinder different from the above-described embodiment may be set as the idle cylinder.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the configuration of an embodiment embodying the present invention.
FIG. 2 is a schematic plan view showing a movement direction conversion mechanism.
FIG. 3 is a partial perspective view of a movement direction conversion mechanism.
FIGS. 4A and 4B are explanatory diagrams showing the relationship between the rotation angle of the output shaft and the stroke of each cylinder when the number of operating cylinders is “4”.
FIG. 5 is an explanatory diagram showing the relationship between the rotation angle of the output shaft and the stroke of each cylinder when the number of operating cylinders is “3”.
FIG. 6 is an explanatory diagram showing the relationship between the rotation angle of the output shaft and the stroke of each cylinder when the number of operating cylinders is “2”.
FIG. 7A is a schematic perspective view schematically showing the form of each crank member when the number of operating cylinders is set to “2” or “4” (during normal operation); FIG. 4 is an explanatory diagram showing a crank angle phase of a crank pin in those crank members.
8A is a schematic perspective view schematically showing the configuration of each crank member when the number of operating cylinders is “4” (when the engine is started), and FIG. 8B is a schematic perspective view of the crankpins of those crank members. Explanatory drawing which shows a crank angle phase.
9A is a schematic perspective view schematically showing the configuration of each crank member when the number of operating cylinders is “3”, and FIG. 9B shows the crank angle phase of each crank pin in those crank members. FIG.
FIG. 10 is a schematic diagram showing a map structure of a map used for determining the number of operating cylinders.
FIG. 11 is a flowchart showing a procedure for controlling the engine.
FIG. 12 is a flowchart showing a procedure for controlling the engine.
[Explanation of symbols]
11: engine (internal combustion engine), 12: piston, 14: output shaft, 55: ECU (variable cylinder control means, phase control means), A: movement direction conversion mechanism (variable phase mechanism), # 1: first cylinder, # 2: second cylinder, # 3: third cylinder, # 4: fourth cylinder, NE: engine speed (rotation speed of output shaft), α: predetermined value.

Claims (9)

A plurality of cylinders are provided, and is used for an internal combustion engine in which a series of strokes for combustion is performed for each cylinder with reciprocation of a piston in each cylinder and an output shaft is rotated,
Variable cylinder control means for changing the number of operating cylinders according to the operating state of the internal combustion engine,
A phase variable mechanism that changes a phase with respect to rotation of the output shaft in the series of strokes in the working cylinder;
A control device for an internal combustion engine, comprising: phase control means for variably controlling the phase by the variable phase mechanism in accordance with a change in the number of operating cylinders by the variable cylinder control means. 2. The internal combustion engine according to claim 1, wherein the phase control unit sets a difference between a phase in a predetermined operating cylinder and a phase in another operating cylinder as a phase interval, and changes the phase interval before and after the phase change. Engine control device. 3. The control device for an internal combustion engine according to claim 2, wherein said phase control means increases said phase interval in accordance with control by said variable cylinder control means for reducing the number of operating cylinders. 4. The control device for an internal combustion engine according to claim 2, wherein the phase control unit reduces the phase interval according to control for increasing the number of operating cylinders by the variable cylinder control unit. 5. 5. The phase control unit according to claim 1, wherein, in accordance with a change in the number of operating cylinders by the variable cylinder control unit, the phase is changed so that the phase interval is substantially equal between the operating cylinders. 6. 3. The control device for an internal combustion engine according to claim 1. The variable cylinder control means, when the internal combustion engine is started, all cylinders are working cylinders, and at least two working cylinders are combustion target cylinders that perform combustion substantially simultaneously,
The phase control means, when the internal combustion engine is stopped, changes the phase so that the strokes of all of the combustion target cylinders become strokes that allow the output shaft to rotate when the engine is started. 6. The control device for an internal combustion engine according to any one of 5. 7. The control device for an internal combustion engine according to claim 6, wherein the stroke that enables the output shaft to rotate is a first half of an expansion stroke. The phase control means holds the phase changed at the time of stopping the engine until the rotation speed of the output shaft exceeds a predetermined value at the time of starting the engine,
8. The control device for an internal combustion engine according to claim 6, wherein the variable cylinder control means continues the combustion performed substantially simultaneously in the combustion target cylinder at the time of starting the engine until the rotation speed of the output shaft exceeds the predetermined value. 9. . The phase control means holds the phase changed at the time of stopping the engine until the number of times of combustion or the number of times of combustion per time exceeds a predetermined value at the time of starting the engine,
8. The control device for an internal combustion engine according to claim 6, wherein the variable cylinder control means continues the phase changed when the engine is stopped until the number of combustions or the number of combustions per time exceeds the predetermined value. .

Images