JPS58195006A - Engine of controllable cylinder number - Google Patents

Abstract

PURPOSE:To aim at causing the pressure balance among respective cylinders to be kept in good condition, by making a stable compressed pressure maintainable in a way of securing a sufficient amount of suction air in the cylinders at the stopping side in time of partial cylinders operation. CONSTITUTION:When an actuator 19 is in operation, a selector ring 15 shifts in an arrow direction so that a rocker arm 14 is pushed to some extent. Therefore, while its follower part exists in a base circle region of first cams 11 and 12, the arm 4 transfers to second cams 13 and 14. Accordingly, at this time a suction valve and exhaust valves are driven to open or close in response to profiles of the correspondent second cams 13 and 14. Each of these first cams 11 and 12 performs opening or closing with the ordinary timing. On the other hand, each of these second cams 13 and 14 keeps a closing state of an exhaust valve 3 intact and opens a suction valve 2 ranging from the exhaust stroke to the suction stroke, closing it in a range from the compression stroke to the expansion stroke. With this method, torque variations can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a cylinder number control engine that performs partial cylinder operation by suspending the operation of some cylinders in a light engine load operating range.

In general, fuel consumption tends to improve when an engine is operated under a high load.For this reason, in a four-stroke multi-cylinder engine, operation of some cylinders is stopped when the load is light, and only this amount remains. A nine-cylinder control engine was devised to relatively increase the load on the operating cylinders and improve fuel efficiency in the light load range as a whole (Japanese Patent Application No. 1983).
-30729 etc.).

The main methods of deactivating some cylinders are to stop the supply of fuel or to restrict the opening of the intake valve and exhaust valve.・It is said to have the advantage that there is relatively little increase in torque fluctuation or rotational fluctuation due to repeated expansion.

However, in a machine that performs partial cylinder operation with the intake and exhaust valves closed, the cylinder pressure in the cylinder on the idle side gradually decreases because blow pie is generated toward the crankcase during repeated compression and expansion. However, the problem arises that torque fluctuations increase.

For example, Figure 1 shows a 4-cylinder engine with $2. This shows the change in the in-cylinder pressure (P, ~P4) of each cylinder when partial cylinder operation is continued with intake and exhaust of the $3 cylinder stopped, but initially the peak values of p, , p, About half of p, p4 is obtained, but if the engine is stopped, the pressure change will be almost smoothed out as shown in the figure, and under this condition, the combustion pressure will reach a peak at every crank angle of 1800 in normal all-cylinder operation. On the other hand, when two cylinders are deactivated, a large pressure peak occurs every 3,600 mph, and as a result of concentrating the mixture in the two operating cylinders, this peak value is considerably higher than when all cylinders are operating. However, there was a problem in that the smoothness of rotation was significantly impaired.

In addition, in the case of a 6-cylinder engine, for example, if you close the intake and exhaust valves of cylinders #4 to #6 and perform partial cylinder operation,
In a 6-cylinder engine, the intake air is compressed during the exhaust stroke, so the compression cycle is as shown in Figure 2.
This overlaps with the combustion cycle of the cylinder, which may actually lead to an increase in torque fluctuation, etc.

This invention was made with attention to such problems, and during partial cylinder operation, either the intake valve or the exhaust valve of the cylinder on the idle side is kept closed, and the other is also controlled during its intake stroke. It is configured to open during the exhaust stroke and close during the compression and expansion strokes, replenishing intake air and preventing pressure drop in the cylinder on the idle side due to continued partial cylinder operation, as well as avoiding compression during the exhaust stroke. An object of the present invention is to provide an engine with a controlled number of cylinders that solves the above-mentioned problems.

Hereinafter, the present invention will be explained based on the drawings. FIG. 3 is a block diagram of a main part showing an embodiment of the present invention, and FIGS. 4 and 5 are a partial detailed view and a partial sectional view thereof.

First, to explain the configuration, in the figure, 1 is the cylinder head, 2 is the intake valve of the cylinder on the idle side, 3 is the exhaust valve, and 4 is the intake valve 2.
5 is a rocker arm on the exhaust valve 3 side, 6 is a rocker shaft, 7 is a bracket that supports the rocker shaft 6 on the cylinder head 1, and 9 is a camshaft.

This camshaft 9 is given a predetermined profile for opening and closing the intake and exhaust valves 2 and 3 via rocker arms 4.5 during normal intake and exhaust strokes, respectively, in cooperation with the pulp spring 10. a first cam 11.12 with a profile given to it, and a second cam 13.12 with a profile described below.
14 are formed adjacent to each other.

On the other hand, the rocker arms 4 and 5 are supported so that they are not only swingable relative to the rocker shaft 6, but also movable in the axial direction between the brackets 70.

At the same time, the rocker shaft 6 has a rocker arm 4,
A switching ring 15 that is slidable in the axial direction is fitted between the rocker arm 4.5 and one of the brackets 7, and the rocker arm 4.5 has a first spring 16 interposed between the switching ring 15 and the switching ring 15.
A second spring 17 interposed between the other bracket 7
The axial positioning is performed according to the tension balance between the

This switching ring 15 is connected via a rod 18 to an actuator 1 composed of a solenoid or a hydraulic cylinder.
The initial positions of the rocker arms 4 and 5 are set such that when the actuator 19 is not in operation, the intake and exhaust valves 2 and 3 are driven to open and close according to the first cam 11.12.

When the actuator 19 is activated, the switching ring 15 moves in the direction of the arrow due to its driving force, and as the spring 16.17 is compressed, the rocker arm 4.5 is pushed, and its 7th opener portion 2o While in the base circle area of the first cam 11.12, it transfers to the second cam 13.14.

Therefore, at this time, the intake and exhaust valves 2.3 are driven to open and close according to the profiles of the corresponding second cams 13 and 14.

Of these, the second cam 14 corresponding to the exhaust valve 3 is the sixth cam.
As shown in the figure, the second cam 1 is formed into a perfect circle with the same diameter as the pace circle of the first cam 120, and corresponds to the intake valve 2.
3, as shown in FIG. 7, the lift portion 21 precedes the first cam 11 by about 90 degrees, and its width is approximately twice that of the first cam 11, and its overall height is approximately half that of the first cam 11. It is formed like this.

That is, in the case of the first cam 11, 12, as shown in FIG. 8, the intake and exhaust valves 2 and 3 are driven to open and close to perform normal intake and exhaust operations.

On the other hand, in the case of the second cam 13, 14, the exhaust valve 3 is kept closed, and the intake valve 2 is opened from its exhaust stroke to the intake stroke, as shown in FIG. It is closed until the expansion stroke.

As a result, there is a means for keeping the exhaust valve 3 corresponding to the cylinder on the idle side closed, and a means for opening the intake valve 2 for a period corresponding to the intake and exhaust strokes, and a means for opening the intake valve 2 for a period corresponding to the compression and expansion strokes. is composed of. Note that these means are formed depending on the number of cylinders on the deactivated side.

FIG. 10 shows an example in which the above means is applied to a 6-cylinder engine, in which cylinders #1 to #3 are used as active cylinders, and cylinders #4 to 6 are used as idle cylinders, and 22 is an intake passage, 23 24 indicates a throttle valve, and 24 indicates an exhaust passage.

A signal from a load cell (not shown) that detects the load state from the opening degree of the throttle valve 23, etc. 1. -Depending on -n, 7
. □ □ K ga, oh, yo -1-2, 78
, the actuator 19 is commanded to operate, and the positions of the rocker arms 4.5 corresponding to the intake and exhaust valves 2 and 3 of the idle side cylinder wells 4 to #6 are controlled by the first cams 11 and 12, respectively.
to the second cam 13.14.

At this time, the fuel injection valves 27 provided in the corresponding intake boats 26 are kept fully closed by a command from the control circuit 25 so that the supply of fuel to the idle cylinders #4 to #6 is cut off.

As a result, the supply of fuel is cut off to cylinders #4 to #6 on the idle side, and the operation (combustion) is suspended. At the same time, intake air is introduced during each intake stroke, and compression action (compression pressure) is applied only during the compression stroke. can get.

On the other hand, fuel and fresh air are of course supplied to the active cylinders #1 to #3, and partial cylinder operation is performed by increasing the load per unit cylinder.

In addition, outside the above light load range, the rocker arm 4.5 returns to the position above the i-th cam 11.12, and the injection valve z
Fuel is supplied from r and 'Js, and normal all-cylinder operation is performed.

With this configuration, during partial cylinder operation, a sufficient amount of intake air is always ensured in the cylinder on the idle side, and a stable and high compression pressure can be maintained in the compression stroke.

For this reason, the compression pressure does not decrease due to continued partial cylinder operation as in the conventional case, and the pressure balance with the active cylinder is maintained in a perfect balance to sufficiently compensate for torque fluctuations and rotational fluctuations caused by partial cylinder operation. can be suppressed to

In addition, since the intake air is not compressed during the exhaust stroke, for example, in the case of a 6-cylinder engine, the compression cycle is prevented from overlapping with the combustion cycle of the active cylinder (the first
(See Figure 1). Therefore, it is possible to effectively reduce torque fluctuations, etc., without causing an increase.

In this embodiment, in this way, the torque during partial cylinder operation,
This prevents the occurrence of irregular vibrations such as fluctuations in
It can be easily applied to engines other than cylinder engines and six-cylinder engines.

As another example, during partial cylinder operation, while the intake valve of the cylinder on the idle side is closed, the exhaust valve 3 is opened during the intake and exhaust strokes and closed during the compression and expansion strokes, as shown in FIG. It can also be configured as

In this case, the first and second cams 1 corresponding to the intake valve 2
1.13 is formed as shown in FIG. 6, and first and second cams 12.14 corresponding to the exhaust valve 3 are formed as shown in FIG. However, in the second cam 14 of the exhaust valve 3, the lift portion 21 is moved back by 90 degrees with respect to the first cam 12.

According to this, of course, the above-mentioned effects can be obtained, and since high-temperature exhaust gas is always introduced into the cylinder on the idle side, there is no fear that the cylinder will be cooled, and wear of various parts can be suppressed as much as possible. Furthermore, since the intake valve 2 is closed, one fuel supply system such as a fuel injection valve is sufficient.

As explained above, according to the present invention, during partial cylinder operation in which fuel supply to some cylinders is cut off and their operation is suspended,
Since either the intake valve or the exhaust valve of the cylinder on the idle side is closed, the other is opened during the intake and exhaust strokes, and closed during the compression and expansion strokes.
It is possible to secure a sufficient amount of intake air in the idle cylinder to maintain stable compression pressure, and the combustion cycle does not overlap with the combustion cycle of the active cylinder, maintaining a good pressure balance between each cylinder, making it possible to maintain a stable compression pressure. Regardless of whether the engine is a 6-cylinder engine or not, it is possible to significantly reduce torque fluctuations during partial cylinder operation, thereby improving driving performance.

[Brief explanation of drawings]

1 and 2 are acupressure diagrams showing changes in cylinder pressure in the active cylinder and the idle cylinder in the conventional example, FIG. 3 is a main part configuration diagram showing an embodiment of the present invention, and FIG. Fig. 5 is a partial detailed view and a partial sectional view thereof, Figs. 6 and 7 are diagrams of the shape of the cam of the present invention, and Fig. 8 is a diagram of the operating state of the intake and exhaust valves in normal conditions.
・・Figure 9 is a diagram of the operation state of the intake valve during partial cylinder operation.・
・Figure 10 is a schematic configuration diagram of an engine to which the present invention is applied,
FIG. 11 shows acupressure lines representing changes in the cylinder pressures of the active cylinder and the idle cylinder of a six-cylinder engine, and FIG. 12 is a diagram showing the operating state of an exhaust valve according to another embodiment of the present invention. 2... Intake valve, 3... Exhaust valve, 4.5... Rocker arm, 9... Camshaft 7), 11.12... First cam, 13114... Second cam , 19... Actuator, 25... Control circuit, 27.28...
fuel injection valve. Tano Nishi□ 1:,,.・１゛□・：′i′; Fig. 3 19 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 List of figures Investigation Point 1. 1 Hole Figure 10

Claims (1)

[Claims] In a multi-cylinder engine that has a dormant cylinder that stops operating when the fuel supply is cut off in the light load range of the engine, and an active cylinder that is constantly supplied with fuel and fresh air and continues to operate,
At the time of the fuel cutoff, means for keeping either the intake valve or the exhaust valve of the cylinder on the idle side closed, and also opening the other for a period corresponding to the intake and exhaust strokes of that cylinder, and keeping the other open for the compression and expansion strokes. A number-of-cylinders control engine characterized by comprising: means for opening the cylinders for corresponding periods.