JP2003184590A - Cylinder cut-off control device for multiple-cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder cut-off control device for a multiple-cylinder internal combustion engine, which suppresses vibration caused by fluctuation of torque of the internal combustion engine. <P>SOLUTION: The control device is provided with an intake air controller 4 placed in intake air paths 2a-2d of respective cylinders 1a-1d of the internal combustion engine 1, and a cylinder cut-off control means, which executes a control for cylinder cut-off in order to shut down operation of a cylinder 1d of the objective cut-off cylinder under predetermined conditions of the engine. The compression ratio of the cylinder 1d is set higher beforehand than a normal compression ratio. In operation for cylinder cut-off, an intake control valve 40 placed in the intake air path of the cut-off cylinder is full opened by the cylinder cut-off control means, and at the same time, fuel injection to the cut-off cylinder is stopped. Difference in cylinder internal pressures between explosion cylinders and the cut-off cylinder is reduced in the cylinder cut-off operation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder internal combustion engine for improving fuel efficiency by suspending operation of some cylinders under predetermined operating conditions of the multi-cylinder internal combustion engine, such as during low load operation. The present invention relates to a reduced cylinder control device.

[0002]

2. Description of the Related Art Conventionally, as a cylinder cut-off control device for improving the fuel efficiency by suspending the operation of some cylinders during a low load operation of a multi-cylinder internal combustion engine, a cylinder cut-off control device which is preset when the execution condition of the cylinder cut-off control is satisfied. Which stops the fuel injection to the reduced cylinders (Japanese Patent Laid-Open No. 53-40124), and when the execution conditions of the reduced cylinder control are satisfied, the fuel injection to the reduced cylinders is stopped and the intake air of the reduced cylinders is intaken. There is known one that shuts off the passage to stop the supply of intake air (Japanese Patent Laid-Open No. 63-65136).

However, such a conventional cut-off cylinder control device is
When the execution condition of the cut-out cylinder control is satisfied, the operation of the cut-out cylinder is stopped as it is by stopping the fuel injection or stopping the fuel injection and blocking the intake passage, and the condition for returning from the cut-out cylinder control during the cut-out cylinder control. If the above condition is satisfied, the operation of the reduced cylinder is restarted as it is.Therefore, when starting the reduced cylinder control or returning to the normal operation, a rapid torque fluctuation occurs in the internal combustion engine, which makes the internal combustion engine uncomfortable. There was a problem of causing vibration.

In order to prevent such torque fluctuation,
Conventionally, when the execution condition of the reduced cylinder control is satisfied, first, the intake passage of one of the plurality of cylinders preset as the reduced cylinder is cut off, and then the intake passages of the other reduced cylinders are cut off. In this way, the number of reduced cylinders for which the operation is stopped is increased stepwise, and when the intake passage of each reduced cylinder is cut off (that is, when the operation is stopped), the intake air amount of the cylinders before and after the operation is continued is suppressed. It has been proposed (Japanese Patent Laid-Open No. 3-70828).

In the proposed device, the output difference between the reduced cylinder and the cylinders before and after the reduced cylinder becomes small, and the reduced cylinder gradually increases. Therefore, the torque fluctuation of the internal combustion engine caused by the reduced cylinder control is suppressed. Will be able to. However, in the proposed device, the number of reduced cylinders is gradually increased, so that there is a problem that it takes time to suspend the operation of all the cylinders set as the reduced cylinders.

Further, when the operation of the reduced cylinder is stopped, the output of the cylinder which should continue the operation before and after the reduced cylinder is also reduced, so that the rapid torque fluctuation due to the stop of the output of the reduced cylinder is suppressed. Although it is possible to do so, there is also a problem that the output torque of the internal combustion engine at the start of the cut-off cylinder control is greatly reduced temporarily. In other words, in a multi-cylinder internal combustion engine, when a specific cylinder is set as a reduced cylinder and its operation is suspended, output torque cannot be obtained from the reduced cylinder, so that a constant output torque is obtained from the internal combustion engine. Is required to increase the output torque of other cylinders that continue to operate more than usual, but in the above proposed device, the output torques of the other cylinders are also reduced before and after the cut-off cylinders are deactivated. The desired output torque cannot be generated. When the number of reduced cylinders is increased stepwise as described above, the torque of the internal combustion engine changes periodically as the number of reduced cylinders increases.

As a solution to the above problem, the applicant of the present invention has previously proposed a cylinder cut-off control device for an internal combustion engine known from Japanese Patent Laid-Open No. 7-217463. This known cut-off cylinder control device gradually changes the open period during the cut-off cylinder intake stroke of the intake control valve provided in the intake passage of the cut-off cylinder at the start and end of the cut-off cylinder control to reduce the cut-off cylinder. The torque fluctuation of the internal combustion engine that occurs at the start and end of control is suppressed.

However, in the case where the cut-out cylinder control is always performed for a specific cylinder preset as the cut-out cylinder, there is no problem if the cut-out cylinder control execution period is relatively short. When the deceleration operation of the engine continues for a long time and the cut-off cylinder control is executed for a relatively long period (for example, about 10 minutes), oil rises in the cut-off cylinder due to the pressure difference with the crank chamber during that period, and the combustion chamber temperature And the spark plug is smoldered. Therefore, in the above-described known cut-off cylinder control device, during execution of cut-off cylinder control, by switching cut-off cylinders in which operation is suspended,
The above problems are prevented from occurring. In each of the above-mentioned conventional techniques, the intake control valve of the reduced cylinder (rest cylinder) is closed during the reduced cylinder operation. Therefore, as shown in FIG. 4A, there is a large difference in in-cylinder pressure between the explosive cylinder and the reduced cylinder, which causes vibration due to torque fluctuations of the internal combustion engine.

[0009]

As described above, in the conventionally known cut-off cylinder control device, in order to suppress the torque fluctuation of the internal combustion engine, the cut-off cylinder of the intake control valve is started and stopped at the start and end of the cut-off cylinder control. In order to prevent the occurrence of problems such as gradually changing the open period during the intake stroke, rising oil in the reduced cylinder, lowering the combustion chamber temperature and smoldering the spark plug, etc. Needing cumbersome control of. Further, the difference in the cylinder pressure between the explosive cylinder and the reduced cylinder is large, which causes engine vibration.

The object of the present invention is to suppress vibrations due to torque fluctuations of the internal combustion engine without requiring such complicated control, and to raise oil in the reduced cylinder, decrease in combustion chamber temperature, and spark plug. It is an object of the present invention to provide a reduced-cylinder control device for a multi-cylinder internal combustion engine that can prevent the occurrence of problems such as smoldering.

[0011]

As a means for solving the above-mentioned problems, the present invention provides a reduced-cylinder control device for a multi-cylinder internal combustion engine according to each of the claims. The cylinder cut-off control device for a multi-cylinder internal combustion engine according to claim 1 sets a compression ratio of a cylinder which is a cylinder cut-off target in advance to a higher compression ratio than a normal compression ratio, and the cylinder cut-off control means performs the cylinder cut-down target during a cylinder cut-off operation. By fully opening the intake control valve of the idle cylinder and stopping the fuel injection in the idle cylinder, the in-cylinder pressure difference between the explosive cylinder and the idle cylinder is reduced. As a result, it is possible to reduce the torque fluctuation and the vibration caused thereby during the reduced cylinder operation. Further, since the cylinder pressure of the deactivated cylinder can be increased, it is possible to prevent the occurrence of oil rise, decrease in combustion chamber temperature, smoldering of the spark plug, and the like.

According to another aspect of the present invention, the cylinder cut-off control device controls the intake control valves of the explosive cylinders to increase the intake amount by the cylinder cut-off control means during the cylinder cut-off operation. The torque can be supplemented even during the reduced-cylinder operation, and the average generated torque can be kept equal to that before the reduced-cylinder operation. According to the third aspect of the present invention, there is further provided a passage switching valve in the exhaust passage of the cylinder subject to the reduction of cylinders, which is capable of switching between an exhaust line passing through the catalyst and a bypass exhaust line not passing through the catalyst. During the cut-off cylinder operation, the cut-off cylinder control means can switch the flow path switching valve so that the exhaust gas from the idle cylinder passes through the bypass discharge line. As a result, the exhaust gas from the explosive cylinder and the blow-through gas from the idle cylinder are mixed to reduce the exhaust gas temperature or dilute the exhaust gas without degrading the catalytic function, and the catalyst can be effectively operated. it can.

According to another aspect of the present invention, in the reduced cylinder control device, during a high load operation, the reduced cylinder control means throttles the intake control valve of the cylinder to be reduced whose compression ratio is set higher than usual. The amount of intake air is reduced, which can prevent the occurrence of knocking due to the high compression ratio of the cylinder to be reduced during high load operation (all cylinder explosion).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A cylinder reduction control apparatus for a multi-cylinder internal combustion engine according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the system configuration of a multi-cylinder internal combustion engine in which the reduced cylinder control device of the present embodiment is mounted. As shown in FIG. 1, this system configuration is provided in a four-cylinder internal combustion engine 1, an intake system 2 and an exhaust system 3 of the internal combustion engine 1, and intake manifolds 2a to 2d connected to each cylinder of the intake system 2. The intake control device 4 and an electronic control unit (ECU) 5 that controls the intake control device 4 and the like.

The internal combustion engine 1 is equipped with four cylinders 1a-1d. Each cylinder 1a-1d is provided with an intake valve (not shown) and an exhaust valve (not shown) that are opened and closed by a high speed compatible cam, and the intake manifolds 2a-2d upstream of the intake valves of each cylinder are provided. Only the air cleaner 6 is provided in the intake system 2 upstream of the intake manifolds 2a to 2d in which the intake control device 4 is provided. In the system configuration of the multi-cylinder internal combustion engine of the present invention, There is no throttle valve that is opened or closed by accelerator operation. A catalyst unit 7 is provided in the exhaust system 3 downstream of the exhaust valves of the cylinders 1a to 1d, and the exhaust system 3 includes an exhaust line 3a that passes through the catalyst unit 7 and a bypass exhaust that does not pass through the catalyst unit 7. A cylinder 1d that has two systems of a line 3b and is a cylinder reduction target by a cylinder reduction operation described later.
The exhaust line 3a and the bypass exhaust line 3
A flow path switching valve 31 that can switch the discharge route between b and b is provided. This flow path switching valve 31
Is switched by the ECU 5.

Further, in the internal combustion engine 1, a crank angle sensor 81 for outputting a pulse signal when the pistons of the cylinders 1a to 1d are located at the top dead center (TDC) as a sensor for detecting the operating state of each cylinder, and for each cylinder. A cylinder discrimination sensor 82 for detecting torque or combustion, an opening sensor 83 for detecting the opening of the intake control valve of the intake control device 4, an air flow meter 84 for detecting the intake air amount of the entire internal combustion engine 1, and an accelerator pedal depression amount. An accelerator opening sensor 85 and the like for detecting the E are provided, and the detection signals from these sensors are
It is output to CU5.

The ECU 5 is configured as an arithmetic logic circuit centering on a CPU, a ROM, and a RAM, and is connected to an input / output unit via a common path to perform input / output with the outside. Detection signals from the respective sensors are input to the ECU 5, from which a rotary solenoid actuator (R / S actuator) and a flow passage switching valve 3 of an intake control device 4 which will be described later are provided.
The control output signal is output to 1. Therefore, this ECU 5
Corresponds to the cut-off cylinder control means of the present invention.

Next, the intake control device 4 will be described with reference to FIGS. FIG. 2 is a vertical sectional view of the intake control device 4. The intake control device 4 mainly includes an intake control valve 40 and an R / S actuator 50. Intake control valve 40
Includes a butterfly-type circular valve plate (valve body) 41 provided inside the intake manifolds 2a to 2d. Circular valve plate 4
1 is rotatably supported by a support shaft 42 and has a very narrow clearance with respect to the wall surfaces of the intake manifolds 2a to 2d and swings around the support shaft 42 in a non-contact manner.
In addition, one end of the support shaft 42 is supported by the intake manifolds 2a to 2d by a bearing 43, and the other end of the support shaft 42 is R
It is connected to the / S actuator 50.

A spring 44 is provided at one end of the support shaft 42 for holding the circular valve plate (valve body) 41 at a neutral position (half open state) when the R / S actuator 50 is not energized. Further, the intake control valve 40 is provided with an opening sensor 83 that detects the opening of the circular valve plate 41.

The R / S actuator 50 comprises a ferromagnetic rotor 51 and a ferromagnetic stator 52. The rotor 51 is connected to a support shaft 42 of the intake control valve 40. FIG. 3 is a cross-sectional view of the R / S actuator 50. The rotor 51 has a solid rod-shaped portion 5 having a circular cross section.
1a and two fan-shaped parts 51b provided symmetrically with respect to the axis of the solid rod-shaped part 51a (axial center of the rotor) and provided on the peripheral surface of the solid rod-shaped part 51a. Has been formed. Electromagnetic coils 53a to 53d are arranged in the stator 52 in four directions at 90 ° intervals, and the stator 52 has electromagnetic coils 53a and 53d.
A pair of projecting portions 52a that taper toward the rotor 51 are formed from the portion where 3c is provided,
Similarly, a pair of extending portions 52b extending from the portion where the electromagnetic coils 53b and 53d are provided and having a concave arc surface whose tip is the same as the arc of the fan-shaped portion 51b is formed.

The intake control valve 40 is fully closed by contacting one side surface of the fan-shaped portion 51b of the rotor 51 with the side surface of one protruding portion 52a of the stator 52, that is, at the position shown in FIG. , The rotor 51 is rotated so that the fan-shaped portion 51b of the rotor 51 is in contact with the circular arc surface of the extending portion 52b of the stator 52, and the rotor 51 is rotated to the side surface of the other protruding portion 52a of the stator 52.
By contacting the other side surface of the fan-shaped portion 51b of the rotor 51,
The intake control valve 40 is fully opened. Therefore, the period during which the intake control valve 40 moves from the fully closed state to the fully open state, that is,
During the movement period of the rotor 51 from the fully closed position to the fully open position, an air gap g is formed between the side surface of the fan-shaped portion 51b of the rotor 51 and the protruding portion 52a of the stator 52, and the rotation of the rotor 51 causes the air gap g to change. Changes. That is, the rotor 51 swings between the two protrusions 52a, and swings in the range of about 90 °.

The intake control device 4 thus constructed is
It works as follows. When the R / S actuator 50 electromagnetic coils 53a to 53d are energized in a predetermined energizing direction,
The rotor 51 in the neutral position by the spring 44 is
The spring 44 overcomes the torque of the spring 44 to rotate and is held in the fully closed position. Therefore, the circular valve plate 41 of the intake control valve 40 directly connected to the rotor 51 is also held from the neutral (half-open) state to the fully closed state. When the energization of the electromagnetic coils 53a to 53d of the R / S actuator 50 is stopped, the rotor 5
1 and the circular valve plate 41 are rotated by the torque of the spring 44, and the rotor 51 reaches near full opening (the circular valve plate 41 is near full opening). In this case, the rotor 51 and the circular valve plate 41 do not reach full opening due to friction and viscous resistance.
In this state, the electromagnetic coil 5 of the R / S actuator 50
3a to 53d are energized in the opposite direction to the previous one (electromagnetic coil 53).
When the energization is performed again by switching the energization directions of b and 53d), the rotor 51 is attracted and held in the fully open position.
Therefore, the circular valve plate 41 of the intake control valve 40 is also held in the fully open state. In this way, the intake air amount for each cylinder of the internal combustion engine is controlled by repeating the above operation (switching the energization direction of the electromagnetic coil) at a desired timing.

Next, the cut-off cylinder control, which is a feature of the present invention and is executed in the ECU 5, will be described with reference to FIGS. 1 and 4. In the present invention, the cylinder 1d to be reduced
That is, the compression ratio of the idle cylinder during the reduced cylinder operation is set to a value higher than the normal compression ratio of about 11, for example, about 14, for example. First, the accelerator pedal depression amount and the internal combustion engine rotational speed, which represent the internal combustion engine load, obtained based on the detection signals from the accelerator opening sensor 85 and the crank angle sensor 81 are read into the ECU 5, and the operating state of the internal combustion engine is read. If the cylinder is in the cylinder reduction control area when the load is low, the cylinder reduction control is performed.

In response to a command from the ECU 5 which is the cylinder reduction control means, the intake manifold 2d of the cylinder 1d which is the cylinder reduction target.
The intake control valve 40 provided in the
By stopping the fuel injection to the cylinder 1d, the cylinder 1d is put into a rest state. Explosion cylinders 1a, 1 in other operating states
b and 1c are provided with E in order to supplement the torque for the idle cylinder 1d.
In response to a command from the CU 5, the opening time of each intake control valve 40 is lengthened and the intake amount is increased, so that the average generated torque is maintained at the same level as before the reduced cylinder operation.

In the exhaust system 3, when the reduced-cylinder operation is started, the flow passage switching valve 31 is instructed by the command from the ECU 5.
Is switched, and the flow of exhaust gas from the idle cylinder 1d is switched from the exhaust line 1a passing through the catalyst 7 to the bypass exhaust line 1b not passing through the catalyst 7. Exhaust gas from the other explosion cylinders 1a, 1b, 1c is discharged through the catalyst 7.

Conventionally, the intake system is provided with a throttle valve that works in conjunction with the accelerator. During low load operation, the amount of air is throttled by the throttle valve, and in addition, it is provided on the intake manifold of each cylinder. The intake control valve is also closed in the idle cylinder. Therefore, as shown in FIG. 4A, the pressure difference between the in-cylinder pressures in the deactivated cylinder and the detonated cylinder is large, which causes vibration and noise of the internal combustion engine during the reduced cylinder operation.

According to the present invention, during low load operation, the cylinder pressure does not rise so much even in the explosive cylinders 1a, 1b, 1c because the intake air amount is small. On the other hand, in the deactivated cylinder 1d, since the intake control valve 40 is fully opened, the intake amount increases, and the compression ratio is set high, so the cylinder pressure increases. Therefore, as shown in FIG. 4 (b), since the pressure difference between the in-cylinder pressures between the explosive cylinders 1a, 1b, 1c and the idle cylinder 1d is small, the vibration and noise of the internal combustion engine during the reduced cylinder operation can be reduced. it can.

In the present invention, the compression ratio of the cylinder 1d, which is the object of cylinder reduction during the cylinder reduction operation, is set higher than the normal compression ratio in advance. Therefore, during high load operation (explosion of all cylinders), the compression ratio between the cylinders is different, which may cause knocking. In order to prevent the occurrence of knocking, the intake manifold 2 of the cylinder 1d is operated during high load operation.
The opening time of the intake control valve 40 provided in d is set to the other cylinders 1a, 1
b, 1c shorter than the opening time of the intake control valve 40,
The amount of intake air to the cylinder 1d is reduced.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a multi-cylinder internal combustion engine equipped with a reduced cylinder control device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of an intake control device used in the present invention.

FIG. 3 is a cross-sectional view of a rotary solenoid actuator of the intake control device used in the present invention.

FIG. 4 is a graph illustrating a difference between (a) conventional cylinder reduction control and (b) the present invention cylinder reduction control.

[Explanation of symbols]

1 ... Internal combustion engine 1a, 1b, 1c ... Explosion cylinder 1d ... idle cylinder 2 ... Intake system 3 ... Exhaust system 3a ... Discharge line 3b ... Bypass discharge line 31 ... Flow path switching valve 4 ... Intake control device 40 ... Intake control valve 5 ... ECU (reduced cylinder control means) 50 ... Rotary solenoid actuator 7 ... Catalyst part 81 ... Crank angle sensor 82 ... Cylinder discrimination sensor 83 ... Opening sensor 85 ... Accelerator position sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F01N 3/20 F01N 3/20 T 3/24 3/24 R F02D 9/02 351 F02D 9/02 351P 361 361G 361J 41/04 310 41/04 310D 43/00 301 43/00 301H 301Z F term (reference) 3G065 AA05 CA13 DA07 GA05 GA41 GA46 HA03 KA34 KA36 3G084 AA03 BA05 BA24 DA02 DA11 DA23 FA10 FA19 FA39 3G091 AA02 DAA28 AB01 HB03 3G092 AA14 AC01 BA01 BB01 BB10 CA03 CA07 CA09 CB05 DC01 DC12 DC15 DF01 DF02 DF09 DG02 DG07 DG09 EA01 EA11 FA05 FA14 FA16 FA20 GA06 GA14 HA01X HA06X HA14Z HB01Z HD09X HE03Z HE05Z 3G301 HA07 JA02 JA04 JA05 JA33 JA37 KA09 LA01 LC01 MA06 MA24 MA25 NE06 PA01Z PA11A PA13A PB03Z PC01Z PE05Z PE06Z

Claims (4)

[Claims] 1. An intake control valve provided in each intake passage of each cylinder of an internal combustion engine, and when not energized, the intake control valve is held in a neutral position where the intake passage is half-opened, and when energized, an energization current is supplied. Accordingly, the rotary solenoid actuator that opens and closes the intake control valve in a direction corresponding to the energization direction, and, under predetermined conditions of the internal combustion engine, suspends the operation of the cylinder that is the target of cylinder reduction, and executes the cylinder reduction control. In a cylinder reduction control apparatus for a multi-cylinder internal combustion engine including cylinder control means, a compression ratio of a cylinder that is a cylinder reduction target is set higher than a normal compression ratio in advance, and during the cylinder reduction operation, the cylinder reduction control means Thus, by simultaneously opening the intake control valve provided in the intake passage of the deactivated cylinder of the deactivated cylinder and stopping the fuel injection of the deactivated cylinder, the explosive cylinder and the deactivated cylinder that are not the reduced cylinder are And a cylinder-reducing control device for a multi-cylinder internal combustion engine, which reduces a cylinder pressure difference between the cylinder and the cylinder. 2. The reduced cylinder operation means controls each intake control valve in the intake passage of the explosive cylinder so as to increase the intake amount of the explosive cylinder during the reduced cylinder operation. Item 2. A reduced cylinder control device for a multi-cylinder internal combustion engine according to Item 1. 3. A flow path switching valve capable of switching between an exhaust line that passes through the catalyst and a bypass exhaust line that does not pass through the catalyst is further provided in the exhaust passage of the cylinder to be cut-off cylinder, and at the time of cut-out cylinder operation. The multi-cylinder internal combustion engine according to claim 1 or 2, characterized in that the flow path switching valve is switched by the cut-off cylinder control means so that exhaust gas from the idle cylinder passes through the bypass exhaust line. Cylinder reduction control device. 4. During high-load operation, the cut-off cylinder control means controls the intake control valve of the cylinder subject to cut-off cylinder whose compression ratio is set higher than usual so as to reduce the intake amount. The reduced cylinder control device for a multi-cylinder internal combustion engine according to claim 1, 2, or 3.