JPH05106686A - Engine controlling number of cylinders - Google Patents

Abstract

(57) [Summary] [Object] To provide a cylinder number control engine in which a balancer shaft is effectively operated to reduce vibration during cylinder deactivation operation without causing output reduction at high speed. A balancer shaft 24 is connected to a crankshaft 21 of an engine body 20 via sprockets 22a and 22b and a chain 23, and an electromagnetic clutch 26 is provided between the shaft end of the balancer shaft 24 and the sprocket 22b. A microcomputer 27 is provided for connecting the electromagnetic clutch 26 only during cylinder deactivation operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder number control engine that deactivates a predetermined cylinder in a low speed / low load range.

[0002]

2. Description of the Related Art As a valve device for an engine of this type aiming at both reduction of fuel consumption at low speed and improvement of intake / exhaust efficiency at high speed, there are conventionally valve devices shown in FIGS.

This is a DOHC type valve device, and this valve device 1 comprises a cam shaft 2 and a rocker shaft 3, and a low speed cam 4 having a small lift amount and a large lift amount are provided on the cam shaft 2. The high-speed cam 5 that it has is fixed.

The rocker shaft 3 is provided with a main rocker arm 6 and a pair of sub rocker arms 7 and 8.

The base end of the main rocker arm 6 described above is integrated with the rocker shaft 3 by, for example, spline connection, and the swing end contacts the valve stem end of the intake valve 9, for example.

On the other hand, the sub rocker arms 7 and 8 are rotatably supported at their base ends by the rocker shaft 3, and the roller bearings 10 are attached to their swing ends.

The swinging ends of the sub rocker arms 7 and 8 are formed by an arm portion 7A (8A) separately from the supporting portion of the roller bearing 10 in FIG. 8 showing the low speed cam 4 side. The arm portion 7A comes into contact with the plunger 13 located at the tip of the lost motion spring 12 provided on the cylinder head 11 and is urged to rotate in the clockwise direction in the drawing to press the roller bearing 10 against the cam. It is like this.

On the other hand, the sub rocker arms 7 and 8 are formed with engagement holes 7B and 8B which penetrate through the sub rocker arms 7 and 8 toward one side in the radial direction with the center part as a boundary. That is, this engagement hole 7
B and 8B form a projecting / withdrawing passage of a connecting plunger described later.

A hydraulic passage 3A is formed inside the rocker shaft 3 along the axial direction at the center of the shaft, and the engagement holes 7B, 8 in the hydraulic passage 3A are formed.
At a position facing B, the base circles of the cams 4 and 5 are orthogonal to the hydraulic passage 3A and the base circles of the roller bearings 1
A through hole 3B is formed so that the central positions thereof can be matched when facing 0.

A connecting plunger 14 which can project and retract between the through hole 3B and the above-described engaging holes 7B and 8B is loaded in the through hole 3B. That is, the connecting plunger 14 has the engaging holes 7B and 8B formed in the sub-rocker arms 7 and 8 as its head, and, for example, at the end opposite to the head in the longitudinal direction of the through hole 3B described above. A compression spring 15 disposed between the formed collar 14A and the support portion in the rocker shaft 3 normally urges the head downward to move the head from the engagement holes 7B, 8B into the through hole 3B. The position to immerse is set.

On the other hand, an output passage of a hydraulic pressure setting means (not shown) is connected to the hydraulic passage 3A in the rocker shaft 3 described above. The hydraulic pressure setting means is for setting the pressure in the hydraulic passage 3A described above according to the operating state, and outputs a drive signal to the two electromagnetically driven directional switching valves for low speed and high speed and these switching valves. The main part is a control unit such as a microcomputer.

With such a configuration, when the microcomputer determines from the input information of the engine speed, the air-fuel ratio and the accelerator opening degree that it is in a relatively low speed state, the electromagnetic wave located on the low speed side is The drive type directional control valve is excited, and the electromagnetic drive type directional control valve located on the high speed side is set to the normal position.

The above-described electromagnetically driven directional control valve on the low speed side is switched to a position in which oil from an oil pump (not shown) is pumped toward the hydraulic passage 3A by being excited, and also on the high speed side. The electromagnetically driven directional control valve located at is maintained in the initial state by not being excited and in a state in which oil is not supplied into the hydraulic passage 3A on the high speed side.

Therefore, the connecting plunger 14 located on the low speed side has the compression spring 15 as shown by the solid line in FIG.
The engaging hole 7 of the first sub-rocker arm 7 against the bias of
By projecting toward A, the rocker shaft 3 and the first sub rocker arm 7 are integrated, and the transmission of the driving force between the sub rocker arm 7 and the rocker shaft 3 is brought into contact with the low speed cam 4. The valve opening / closing control can be performed, and the connecting plunger 14 on the high speed side is left immersed in the through hole 3B of the rocker shaft 3 and is positioned on the high speed side, as shown by the chain double-dashed line in FIG. The transmission of the driving force between the second sub rocker arm 8 and the rocker shaft 3 is maintained in the disconnected state so that the valve opening / closing control by the high speed cam 5 is not exerted.

On the other hand, when the engine speed rises and reaches the high-speed rotation range, the electromagnetically driven directional control valve located on the high speed side is opposite to the above-described excitation setting for the electromagnetically driven directional control valve at low speed. The excitation setting for is performed. Therefore,
In this case, as shown in FIG. 9 used in the description of the low speed side, the connecting plunger 14 located on the high speed side is directed toward the engagement hole 8B of the second sub-rocker arm 8 as shown by the solid line. The second sub-rocker arm 8 and the second sub-rocker arm 8 are integrated by projecting the second
The transmission of the driving force between the sub rocker arm 8 and the rocker shaft 3 is set to the contact state. At this time, the connecting plunger 14 on the low speed side is converted into a position in which it is removed from the engagement hole 3A of the first sub-rocker arm 7 and retracted into the through hole 3B of the rocker shaft 3.

As a result, the valve opening / closing control by the high speed cam 5 is performed.

Further, at the low speed mentioned above, for example,
When it is determined from the input from the throttle position sensor that the engine is operating in a low load state such as idling, the opening / closing control by the low speed / high speed side cam in the selected cylinder is not performed. It

That is, in this state, the control unit releases the excitation setting for the electromagnetically driven directional control valves located on the low speed side and the high speed side.

Therefore, since the pressure-feeding position of the oil is not set by either the low speed side or the high speed side electromagnetically driven directional control valve, the pressure in the hydraulic passage 3A of the rocker shaft 3 does not rise, whereby each side is prevented. Connecting plunger 14
Is set to a normal position in which it is retracted into the through hole 3B by the biasing force of the compression spring 15, and the transmission of the driving force between the first and second sub-rocker arms 7 and 8 and the rocker shaft 3 is cut off. maintain.

As a result, each sub rocker arm 7, 8
Is a so-called valve stop state in which the open / close control by the low speed and high speed cams 4 and 5 is not applied, and the cylinder deactivated state is set here. Then, the cylinder deactivated state is switched to the setting of the operation position of the connecting plunger 14 according to the engine speed when the low load state is released.

[0021]

By the way, in an engine equipped with the above-mentioned valve device, vibration is particularly great during idle cylinder deactivation operation, and its solution is urgently needed.

Therefore, in order to reduce the above-mentioned vibration, it may be considered to attach a balancer shaft, but in this case, there is a problem that the output is reduced due to friction or inertia at high speed.

The present invention has been proposed in consideration of the above-mentioned circumstances, and the number of cylinders control can be performed by effectively operating the balancer shaft to reduce vibration during cylinder deactivation operation without lowering output at high speed. The purpose is to provide an engine.

[0024]

To achieve the above object, the structure of the present invention is a cylinder number control engine in which the operation of a predetermined cylinder is stopped in a low speed / low load region of the engine. A balancer shaft that is interlocked with the shaft via a clutch is provided, and a control means that connects the clutch only during the cylinder deactivation operation is provided.

[0025]

According to the above structure, vibration can be reduced by rotation of the balancer shaft during cylinder deactivation operation, while output can be increased by non-rotation of the balancer shaft during high speed operation.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the crankshaft 21 of the engine body 20 includes a pulley 22a, 22b and a belt 2
One balancer shaft 24 is connected via 3.

The engine main body 20 has a valve device (not shown) similar to that described in the prior art, and is composed of a cylinder number control engine that stops the operation of a predetermined cylinder during idling.

The balancer shaft 24 is rotatably supported by a transmission case or the like (not shown) via bearings. As shown in FIG. 2, an eccentric weight 25 is fitted on the shaft thereof. There is.

An electromagnetic clutch 26 is interposed between the shaft end of the balancer shaft 24 and the pulley 22b on the balancer shaft side.

The electromagnetic clutch 26 is supplied from a microcomputer 27 to which information such as engine speed and throttle position is inputted (this may also serve as the variable valve timing microcomputer described in the prior art). The drive signal allows connection only during idle cylinder deactivation.

Then, in the above connection, FIG. 3 and FIG.
The phase matching mechanism as shown in FIG. 5 performs phase matching between the crankshaft 21 and the balancer shaft 24 so that the eccentric weight 25 comes in the direction opposite to the rolling direction of the engine body 20 shown in FIG.

The phasing mechanism comprises a clutch body 26a.
When the clutch is turned on, the key 28 is projected from the side and the key 28 is fitted into the slit 29 formed in the clutch plate 26b on the pulley 22b side.

With such a configuration, the microcomputer 27 controls the electromagnetic clutch 26 based on the flowchart shown in FIG.

That is, it is determined in step P ₁ whether or not the cylinder deactivation operation is in progress. If not, the electromagnetic clutch 26 is disengaged in step P ₄ . As a result, the balancer shaft 24 is not rotated, and a decrease in output at high speed is avoided.

On the other hand, if the cylinder deactivation operation is in progress, then it is determined in step P ₂ whether or not the engine is idling. If it is not idling, the electromagnetic clutch 26 is started in step P _4.
Is disengaged and the balancer shaft 24 is not operated as described above, and if idling, the electromagnetic clutch 26 is engaged in step P ₃ .

As a result, the balancer shaft 24 rotates and the vibration in the operating range is reduced. At this time, the balancer shaft 24 rotates at the same speed as the engine speed, so that the primary vibration of the crankshaft 21 is effectively absorbed.

The present invention is not limited to the above embodiment,
It goes without saying that various modifications such as using a mechanical clutch as the clutch and operating the balancer shaft 24 even during the cylinder deactivation operation during traveling are possible without departing from the scope of the present invention.

[0038]

As described above, according to the present invention, the balancer shaft is made to act only during the cylinder deactivation operation by using the clutch, so that the vibration during the cylinder deactivation operation is not caused at the time of high speed output reduction. It can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram around an engine showing an embodiment of the present invention.

FIG. 2 is a side view of the balancer shaft.

FIG. 3 is a perspective view of the phase matching mechanism.

FIG. 4 is a side view of the phase matching mechanism.

FIG. 5 is an explanatory view of the rolling direction of the engine body and the balancing direction of the eccentric weights.

FIG. 6 is a flow chart showing an operation procedure of the microcomputer of the same.

FIG. 7 is a perspective view of a main part of a conventional valve device.

FIG. 8 is a sectional view of the same main part.

FIG. 9 is an overall sectional view of the same.

[Explanation of symbols]

 20 Engine Body 21 Crankshaft 24 Balancer Shaft 26 Electromagnetic Clutch 27 Microcomputer

Claims (1)

[Claims] 1. A cylinder number control engine in which the operation of a predetermined cylinder is stopped in a low speed / low load range of an engine, a balancer shaft which is interlocked with a crank shaft of the engine via a clutch is provided, and the clutch is provided. A cylinder number control engine provided with a control means connected only during the cylinder deactivation operation.