JPS58202341A - Cylinder number control engine - Google Patents

Abstract

PURPOSE:To keep the combustion of cylinders at the stopping side in good condition as well as to improve the accelerability of an engine, by opening a fresh air cutoff valve in a suction passage at the stopping side after closing an exhaust reflux value installed in each cylinder at the stopping side, in time of changing over from partial cylinder operation to all-cylinder operation in a multicylinder engine. CONSTITUTION:In time of light load in an engine consisting of cylinders D and E at the stopping side and cylinders A and B at the operating side, a fresh air cutoff valve 10 installed in a suction passage 4 at the stopping side is closed while an exhaust reflux valve 12 in an exhaust circulating passage 11 installed in a space between the stopping side suction passage 4 and an exhaust passage 7 at the stopping side is opened. From this condition, when shifting to all-cylinder operation, first the exhaust reflux valve 12 is closed, then the fresh air cutoff valve 10 is opened somewhat being delayed though, so that suction pressure inside the stopping side suction passage 4 is raised up whereby exhaust gases out of cylinders at the stopping side will not be sucked into cylinders at the operating side, thus a state of combustion is favorably maintained and furthermore both drivingness and accelerability are improved.

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 range or the like.

In general, fuel efficiency tends to improve when an engine is operated under a high load. Therefore, in a multi-cylinder engine, fuel supply to some cylinders is cut to stop operation when the engine load is light. An engine with controlled number of cylinders was devised that relatively increases the load on the remaining active cylinders by that amount, thereby improving overall fuel efficiency in the light load range.

(% Application No. 50-28770.54-30729, etc.) In this type of engine previously proposed by the present applicant, as shown in Fig. 1, cylinders A-C on the operating side and cylinders D-C on the idle side Correspondingly, the intake passage 1 is divided downstream of the throttle valve 2 into an operating side intake passage 3 and an idle side intake passage 4 (and is divided into an operating side exhaust passage 6 and an idle side exhaust passage 7 halfway through the exhaust passage 5). It is divided.

When the operation of cylinders D-F is completely stopped in the light load range of the engine, for example, based on the intake air amount signal from the intake air position needle 8 and the rotation speed signal from the ignition coil, which is slow as shown in the figure, the engine speed is compared to the rotation speed. When the load falls below a predetermined value, the control circuit 9 activates the fuel injection valve d corresponding to the cylinder D-F.
-ft, the fuel supply t-m is cut off, and the fresh air cutoff valve 10 provided at the upstream portion of the idle-side intake passage 4 is closed.

At the same time, the exhaust gas recirculation valve 12t of the circulation passage 11 connecting the downstream side of this cutoff valve 1O and the idle side exhaust passage 7 is opened to recirculate a part of the exhaust gas to the idle side cylinder DNF.

As a result, partial cylinder operation is performed by operating only the active cylinders A to C while reducing the pumping loss in the idle cylinders D to F.

Further, partial cylinder operation is performed in the same manner during idle link when the throttle valve 2 is fully closed and both the load rotational speeds are small. However, during one-part cylinder operation.

To keep the engine output the same as when operating on all cylinders.

In the control circuit 9, the injection valves 1 to 1 corresponding to the working cylinders A-C
The injection constant of C is switched to approximately double.

However, in such a conventional example.

This is because when switching the number of cylinders, the fresh air cutoff valve 10 of the idle-side intake passage 4 and the exhaust gas recirculation valve 12 of the exhaust circulation passage 11 are opened and closed at the same time.

For example, when transitioning from partial cylinder operation to full cylinder operation, exhaust gas recirculated to the idle cylinder D-FK via the exhaust circulation passage 1111 passes from the idle side intake passage 4 to the cutoff valve 10 and passes through the active side intake passage 3. There was a problem in that the fuel flowed into the engine and was sucked into the operating cylinders A-C. As a result, the combustion state temporarily deteriorates, leading to a decrease in output, which significantly impairs drivability, especially at the beginning of acceleration.

This invention was made by focusing on these conventional problems.In order to shift from one partial cylinder operation to full cylinder operation, the exhaust recirculation valve is first closed, and then, after a certain delay, the fresh air cutoff valve is opened. To provide an engine with a controlled number of cylinders, which solves the above problem by completely increasing the negative pressure in the intake passage on the idle side, thereby preventing the exhaust gas recirculating the cylinder on the idle side from flowing into the active cylinder. With the goal.

The present invention will be explained below based on the drawings.

FIG. 2 shows an embodiment of the present invention, which is an example applied to a four-cylinder engine. In this example, there are active cylinders A and B that are constantly supplied with fuel and fresh air and continue to operate, and a dormant cylinder that stops operating (stops combustion) when the fuel supply is cut off at the light load region.

The position of E is swapped with that in FIG. 1, and a carburetor 13 (not limited thereto) is used as a fuel supply device instead of the fuel injection valve 1%f.

The intake passages 1 and exhaust passages 5 correspond to these cylinders A, B, D, and E, respectively, and the working side intake passages 3 and the idle side intake passages 4. It is divided into a working side exhaust passage 6 and a resting side exhaust passage 7, and a fresh air cutoff valve l is installed in the upstream part of the resting side intake passage 4.
An exhaust gas recirculation valve 12 is interposed in the middle of an exhaust circulation passage 11 that connects the idle-side intake passage 4 and the idle-side exhaust passage 7 downstream of this cutoff valve 10.

For example, a solenoid valve is used as the exhaust gas recirculation valve 12, and when excited by a command from the control circuit 14, the exhaust circulation passage 11t is closed, and when opened, the passage 11 is opened.

On the other hand, the fresh air cutoff valve 10 is connected to a diaphragm device 15 as a driving means, and selectively introduces engine suction negative pressure (negative pressure inside the working side intake passage 3 and atmospheric pressure) into the negative pressure chamber 16. A three-way solenoid valve 17 is provided.

This three-way solenoid valve 171'! , the control circuit 14 via a diaphragm switch 18t which is opened and closed in response to the differential pressure between the negative pressure inside the working side intake passage 3 and the negative pressure inside the idle side intake passage 4.
When the diaphragm switch 18 is connected to the battery 19 and is energized, atmospheric pressure is introduced into the diaphragm device 15 and the fresh air cutoff valve 10' is opened.

When the switch 18 is turned off and opened, suction negative pressure is introduced and the fresh air cutoff valve 101 is closed.

This seven-diamond ram switch 18 includes a spring 21 that presses the diaphragm 20 from behind, and a spring 21 that presses the diaphragm 20 from behind.
The working side intake passage 3 is connected to the first negative pressure chamber 23 on the side of the spring 21 which is defined by a contact point 22 which is connected and disconnected by the back and forth movement of Are the side intake passages 4 communicating with each other, and are the negative pressures tX of both sides equal?

Alternatively, if the negative pressure in the idle side intake passage 4 is stronger than the negative pressure in the working side intake passage 3, it is set so that it becomes conductive and opens when it becomes weaker.

A load sensor 26 that is linked to the accelerator pedal 25
(Also, based on the load signal from the intake air indicator 89 and the rotation signal from the rotation sensor 2F5 (or ignition coil 29) provided on the crankshaft 27, the control circuit 14 is activated in the light engine load range or when the engine is idle. Exhaust recirculation valve 12t - open, exhaust recirculation valve 1 in other areas
Command to close 2.

When this exhaust recirculation valve 12 is opened, the negative pressure in the idle side intake passage 4 becomes weaker than the negative pressure in the working side intake passage 3, so the diaphragm switch 18 is turned off, and the three-way solenoid valve 17 is switched. A suction negative pressure is introduced into the diaphragm device 15. As a result, the fresh air cutoff valve 1o closes after some delay.

The supply of air-fuel mixture from the carburetor 13 to the idle cylinder E is cut off, and its operation is completely stopped, and partial cylinder operation is performed (as shown).

On the other hand, when the exhaust recirculation valve 12 closes, the negative pressure in the idle side intake passage 4 rises, and when this exceeds the negative pressure in the active side intake passage 3, the diaphragm switch 18 is turned on and atmospheric pressure is applied to the diaphragm device 15. be introduced. Therefore, the fresh air cutoff valve 10 is opened after a delay, thereby restarting the supply of air-fuel mixture to the cylinder on the side where the cylinder is closed and restoring its operation.
The partial cylinder operation is shifted to full cylinder operation as shown in FIG.

That is, when restoring the operation of the cylinder E on the inactive side.

A control means is configured to open the fresh air cutoff valve lO after closing the exhaust recirculation valve 12, and the negative pressure in the intake passage 4 on the idle side is
The fresh air cutoff valve 10 is prevented from opening until the negative pressure in the working side intake passage 3 becomes approximately equal to or higher than the negative pressure.

Note that 30 in Figure 1 is the cylinder connected to the idle side from the ignition coil 29 via the distributor 31.

This is a switch that interrupts the ignition current sent to the spark plug (not shown) of E, and is opened by a command from the control circuit '14 when the actuator 1 is stopped, thereby saving power.

With this configuration, when transitioning from one partial cylinder operation to full cylinder operation, the exhaust recirculation valve 12 is closed, and then the fresh air cutoff valve 10 is closed after the negative pressure in the intake passage 4 on the idle side has sufficiently increased. will be held.

Therefore, during one-part cylinder operation, the exhaust circulation passage 11'? The exhaust gas that is recirculated to the idle side cylinders through It is cleanly discharged from the cylinder E through the idle side exhaust passage 7.

Therefore, the combustion state in the operating cylinders A and B is maintained well, while in the idle cylinders and E, the air-fuel mixture is supplied from the carburetor 13 at the same time as exhaust noise is emitted, and combustion starts immediately. be done.

As a result, the operating cylinders A and B, and the idle cylinder.

E can operate smoothly, and good drivability can be obtained without causing a temporary decrease in output unlike the conventional example, and acceleration performance etc. can be improved.

On the other hand, when transitioning from full cylinder operation to partial cylinder operation,
The exhaust gas recirculation valve 12 is opened and the negative pressure in the intake passage 4 on the idle side is weakened, and at the same time the fresh air cutoff valve 1o is closed.
The downstream air-fuel mixture is combusted in the cylinder E, and then the exhaust gas is recirculated from the exhaust circulation passage 11 to the idle cylinder and E.

Therefore, the transition to 5-part cylinder operation is carried out smoothly.
The engine condition is maintained in good condition.

During partial cylinder operation, the exhaust gas is recirculated to the idle cylinder E, and as this is repeatedly compressed and expanded, the combustion pressure is almost balanced with the combustion pressure in the active cylinders A and H, as shown in Figure 4. It is possible.

Therefore, torque fluctuations and rotational fluctuations do not increase significantly compared to the operating pressure state during all-cylinder operation shown in FIG. 5, and the occurrence of unpleasant vibrations can be sufficiently suppressed.

Of course, since the pressure inside the intake passage 4 on the idle side becomes approximately atmospheric pressure, the pumping loss can be reduced.

In this embodiment, the opening/closing timing of the fresh air cutoff valve 10 relative to the exhaust gas recirculation valve 12 may be controlled by the control circuit 14.

As explained above, according to the present invention, in a cylinder number control engine in which the fresh air cutoff valve is closed during partial cylinder operation and the exhaust recirculation valve is opened to recirculate engine exhaust gas to the cylinder on the idle side, When returning from operation and transitioning to all-cylinder operation, the fresh air cutoff valve is fully opened after a certain delay after the exhaust recirculation valve is fully closed, increasing the negative pressure in the intake passage on the idle side, so that the exhaust gas recirculation valve is fully closed and the negative pressure in the intake passage on the idle side is increased. This has the effect that the exhaust gas generated by the combustion engine is not sucked into the operating cylinder, and the combustion state 1 engine state can be maintained in good condition to improve driveability and acceleration.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the configuration of a conventional example, FIG. 2 is a cross-sectional view of the configuration of an embodiment of the present invention, FIG. 3 is a diagram of the operating state of the present invention during all-cylinder operation, and FIGS. 4 and 5. are acupressure diagrams showing changes in cylinder pressure during partial cylinder operation and full cylinder operation, respectively. 2... Throttle valve, 3... Working side intake passage, 4... Stopping side intake passage, 6... Working side exhaust passage - 7... Stopping side exhaust passage, 10... Fresh air cutoff Valve, 11...Exhaust circulation passage. 12... Exhaust recirculation valve, 13... Carburizer, 14...
Control circuit, 15...Diaphragm device, 17...Three-way solenoid valve, 18...Die'? 7 Ram Switch, 26
...Load sensor, 28... Rotation sensor. Patent applicant Nissan Motor Co., Ltd. No. 4M Fig. 5

Claims (1)

[Scope of Claims] A multi-cylinder system comprising a dormant cylinder whose fuel supply is interrupted and its operation ceases in the light load range of the engine, and an active cylinder which is constantly supplied with fuel and fresh air and continues to operate. In an engine, the intake passage is divided from the upper middle corresponding to the cylinder on the idle side and the cylinder on the operating side, and the exhaust passage is similarly divided halfway, and the fresh air cutoff valve that closes when the operating body is stopped is installed in the intake passage on the idle side. ,
An exhaust circulation passage is formed that connects the idle-side intake passage downstream of the connecting valve to the idle-side exhaust passage, and the exhaust circulation passage is provided with an exhaust recirculation valve that opens when the operating body is stopped. 4! A control means is provided which opens a fresh air key valve after closing the exhaust gas recirculation valve when restoring the operation of the cylinder on the idle side.
The characteristic is a cylinder number controlled engine.