JPS59110858A - Ignition timing control device for engine with its number of cylinders controlled - Google Patents

Abstract

PURPOSE:To suppress shocks likely when the number of cylinders in service is to be changed over, by so controlling the ignition delay angle of a cylinder to be put in standstill or restituted to service as to change gradually, when a changing-over is sensed from the reduced cylindrical operation to the full is sensed or vice versa. CONSTITUTION:If a control device 8 has judged that the load of engine obtained from the output of a throttle opening sensor 7 etc. is of a one of low-load operating condition, the internal cylinders E1 is put out of operation, only external cylinders E0 being left in service. Said control device 8 is equipped with a sensor for the number of cylinders in service. This sensor is to sense the event of changing over from the reduced cylindrical operation to the full or vice versa. Control shall be so performed that the ignition delay angle of the cylinder to be put in standstill or restituted to service will change gradually, when said sensor gives a change-over signal, so as to suppress shocks likely to be generated when changing-over of the number of cylinders takes place.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for an engine with a controlled number of cylinders, and more particularly to an ignition timing control device for an engine with a controlled number of cylinders, which stops combustion in a specific cylinder in a specific operating state and operates with the remaining cylinders. The present invention relates to an ignition timing control device.

In general, the higher the engine load, the better the fuel efficiency tends to be.In recent years, multi-cylinder engines have stopped the fuel supply to some groups of cylinders when the engine load is light, thereby reducing the fuel consumption of the remaining operating cylinders. Engines that control the number of cylinders are being put into practical use, which relatively increases the load on the engine and improves fuel efficiency in low-load operating ranges. However, this conventional engine with cylinder number control has a drawback in that torque fluctuations are large when switching between full-cylinder operation and reduced-cylinder operation, which causes extreme discomfort to the driver.

To overcome this drawback of conventional cylinder number controlled engines,
For example, as shown in Japanese Patent Application Laid-Open No. S-IJA32, the fuel supply to the cylinders is stopped in a predetermined cycle depending on the no-load or low-load state of the engine, thereby preventing large torque fluctuations. There are ways to prevent this. However, if fuel supply to the cylinders is stopped in a predetermined cycle, the average torque fluctuation becomes smooth to some extent, but since reduced cylinder operation and full cylinder operation are still repeated, the torque fluctuation in the adjacent cycle is The problem is that it's big.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of conventional engines with controlled number of cylinders, the present invention provides an ignition timing control device for an engine with controlled number of cylinders that can switch between reduced-cylinder operation and full-cylinder operation with smooth torque fluctuations. The purpose is to

The present invention provides an ignition timing control device for an engine with cylinder number control that stops combustion in a specific cylinder and operates the remaining cylinders in a specific operating state. A number-of-operating-cylinder detector detects the switching from operation to reduced-cylinder operation and generates a switching signal, and upon receiving the switching signal, gradually changes the ignition retard amount of the cylinder to be stopped or restored. The present invention is characterized in that it is provided with an ignition retard amount controller that controls the amount of ignition retardation.

Specifically, the ignition timing control device for an engine with a plurality of cylinders with multiple cylinders according to the present invention configured as described above delays the ignition timing of the returning cylinder by a relatively large predetermined value, for example, when switching from reduced-cylinder operation to full-cylinder operation. By reducing the generated torque of the returning cylinder immediately after the switching, and then gradually bringing the ignition timing closer to the ignition timing of the other cylinders, that is, by gradually reducing the ignition retard angle, the generation of the returning cylinder is reduced. The torque is brought close to the torque generated by other cylinders, and when switching from current cylinder operation to reduced cylinder operation, the ignition timing of the cylinder to be deactivated is delayed by a relatively small predetermined value, that is, the ignition timing is retarded by a small amount. By doing this, the generated torque of the cylinder to be deactivated is slightly reduced before completely reducing the number of cylinders, and then by gradually increasing the amount of retardation of the ignition timing, the generated torque of the cylinder to be deactivated is reduced. Since the torque is gradually reduced and finally stopped completely, the torque fluctuation when switching between reduced-cylinder operation and full-cylinder operation is smoothed out, and there is no torque shock.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ignition timing control device for an engine with controlled number of cylinders according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

, f-7 are schematic diagrams of a cylinder number controlled engine equipped with an ignition timing control device according to an embodiment of the present invention.

In Figure 1, the symbol E indicates a t-cylinder engine installed in a car. As will be explained in detail later, this engine E only uses the outer cylinder EO during low-load operating conditions such as idling or deceleration. The number of cylinders is controlled so that the inner cylinder E1 is activated and the inner cylinder E1 is deactivated.

The intake system of the engine E includes an intake pipe section 1, a throttle valve 2, and an intake manifold 3.

This intake manifold 3 has the above-mentioned Hirono cylinder F'1+EO.
The intake manifold portions 3m+3b*3c and 3d are each individually connected to each other. This intake manifold part 3m, 3b.

3e and 3d each have 1. Fuel injection valves 4a, 4b, 4e, and 4d are provided.

An air flow meter 5 and an air cleaner 6 are provided upstream of the throttle valve 2 in the intake pipe section 1 . This air flow meter 5 detects the amount of intake air flowing through the intake pipe line 1, and outputs an intake air amount signal S1 corresponding to the amount of intake air.
It is designed to output .

The throttle valve 2 is provided with a throttle opening sensor 7 that detects the throttle opening and outputs a throttle opening signal S2 corresponding to the throttle opening in order to detect the engine load. Output ends of the air flow sensor 5 and throttle opening sensor 7 are respectively connected to input ends of a control device 8 comprising a microcomputer or the like.

The other input terminal of this control device 8 includes a crank angle sensor 9 that detects a crank angle and outputs a crank angle signal S5 corresponding to the crank angle, and a crank angle sensor 9 that detects the output torque of the engine E and outputs a crank angle signal S5 corresponding to the crank angle. The torque sensor 10 outputs a torque signal S4 according to the
each connected.

The control device 8 receives an intake air amount signal S1, a throttle opening signal S2, a crank angle signal S5, and a torque signal S from the air claw sensor 5, throttle opening sensor 7, crank angle sensor 9, and torque sensor 10.
4, and in response to these signals, the fuel injection valve 4a +
4b + 4e * 4a fuel injection amount and injection timing, and each cylinder EO.

Spark plugs installed in El 11 m, 1 l b,
11 e.

The ignition timing is controlled by the lid. Further, this control device 8 is capable of controlling the fuel injection valves 4b and 4e for the inner cylinder E1 and the fuel injection valves 4m and 4d for the outer cylinder EQ in separate systems, and controls the throttle opening. When the throttle opening signal 82 from the sensor 7 is smaller than a predetermined value, that is, when the engine is operating at low load or idling, a cylinder number control flag is set, and the fuel injection valve 4b to the inner cylinder E1 is injected according to this flag. , 4e is stopped, the inner cylinder E1 is deactivated, and only the outer cylinder is operated in a reduced cylinder operation, and on the other hand, when the throttle opening signal S2 from the throttle opening sensor 7 is larger than the predetermined value,
In other words, all cylinders can be operated during medium-load or high-load operation of the engine.

However, when switching from the reduced-cylinder operation to the full-cylinder operation, in the example described above, the number of active cylinders doubles, so the generated torque also doubles, giving a shock to the driver.

Therefore, in the present invention, when returning to all-cylinder operation,
Spark plugs llb and li of the inner cylinder E1, which is the return cylinder
The ignition timing of cylinder E1 is delayed by a predetermined value to gradually return to the normal ignition timing, thereby gradually increasing the generated torque of the cylinder E1, thereby preventing the torque shock at the time of switching the operation.

Next, with reference to the following figures, the ignition timing control of the restored cylinders when switching from the reduced cylinder operation to the full cylinder operation will be described in detail.

This diagram is a flowchart of the ignition timing control described above by the control device 8.

In order to determine the ignition timing of the inner cylinder E1, it is first determined whether the cylinder number control flag for performing the above-mentioned cylinder number control is set. If this determination is No, then it is determined whether the cylinder number control flag was in the reset state during the previous control cycle as well, and it is determined whether or not it is the moment to return to all cylinder operation. When this determination is YES, that is, at the moment when all cylinder operation is resumed, the throttle opening speed d
``Tv0 and the generated torque T of the engine E during partial cylinder operation immediately before the current control cycle, the retardation correction amount initial value C...t=11 (μ'TVO, To determine the time t=t (Tvo, To) and the retardation correction control time t. Then,
Ignition flags 11b and 11e of the inner cylinder E1, which is the return t cylinder.
The ignition timing is corrected to be retarded by the value Ceut from the normal ignition timing, and the control of this cycle is completed. Please note that the ignition timing has been remade immediately after returning to full cylinder operation.
cut is the above initial value Ccut o.

In the next control cycle as well, it is first determined whether or not the cylinder number control flag is set, but in this case the determination is of course NO, so next it is determined whether it is the moment when all cylinders are returned to operation. It will be done. Since this control cycle is not immediately after returning to all-cylinder operation, this judgment is N
It becomes O. Next, it is determined whether the retardation correction control time t is O. If this determination is No, that is, time r11J't
is not 0, the above Ccut o I! : The ignition timing is advanced by the amount that should be advanced in one control cycle determined by t, that is, the Ccut is attenuated, and the control time Δt for one control cycle is counted down. Next, the ignition flag 11b.

ie attenuated above from the normal ignition timing.
The ignition is retarded. The above control is performed until 1=0, and the generated torque of the restored cylinder E1 is gradually increased to prevent torque shock immediately after all cylinders are returned to operation.

In the above control, it is determined whether the cylinder number control flag is set, that is, whether cylinder reduction operation is being performed, and whether t=θ, that is, whether the ignition timing of the reduced cylinder is the same as the ignition timing of other cylinders. When is YES, fuel is not supplied to the idle cylinder, so there will be no problem even if the ignition timing of that cylinder is set to normal ignition timing, so ignition is performed at the normal ignition timing.

The relationship between the setting of the cylinder number control flag, the reset state, the retard amount, and the torque value in the above control is as shown in the time chart in Figure 3, and the generated torque of engine E gradually increases after all cylinders return to operation. I know what you're doing. In addition, in Figure 3, the symbol A indicates the time of reduced cylinder operation, and the symbol B indicates the time of reduced cylinder operation.
indicates when all cylinders are operating.

Next, the circuit for controlling the ignition timing explained above is as follows.
The explanation will be given with reference to the block diagram of the 3D diagram.

The throttle opening sensor 7 receives a signal S from the sensor 7.
An acceleration determination circuit 12 is connected which determines whether or not the vehicle is in an acceleration state based on 2. On the other hand, a torque determination circuit 13 that determines the magnitude of the torque generated by the engine E is connected to the torque sensor 10. The outputs of the acceleration determination circuit 12 and the torque determination circuit 13 are determined by the retardation correction amount calculation circuit 1.
It is connected to the input terminal of 4. The other input terminal of this retard angle correction amount calculation circuit 14 is connected to a cylinder number control end signal generation circuit 1.
5 is connected. This cylinder number control end signal generation circuit 15 has an input end connected to the output end of the cylinder number control circuit 16, and generates a cylinder number control end signal when the cylinder number control circuit 16 ends its operation. When the retard correction amount calculation circuit 14 receives the cylinder number control end signal from the circuit 15, it receives a signal indicating the acceleration state from the acceleration determining circuit 12 and a signal indicating the torque state from the torque determining circuit 13. Then, based on these signals, the retard angle correction amount initial value Ccuto and the retard angle correction control time t are calculated. A retard control circuit 17 is connected at its input end to the output end of the retard correction amount calculation circuit 14, and this retard control circuit 17 outputs an output to the return cylinder ignition circuit 18 based on the above Ccut o and t. Then, the ignition timing of the spark plugs llb and lie is controlled according to the flowchart shown in the diagram.

In addition, in the above embodiment, ignition timing control when switching from reduced cylinder operation to all cylinder operation was explained, but the present invention is also applicable to ignition timing control when switching from all cylinder operation to reduced cylinder operation. can do. In addition, the ignition timing control at the time of switching in this case is performed by delaying the ignition timing of the cylinder to be stopped by a relatively small predetermined value, that is, by retarding the ignition timing of the cylinder by a small amount immediately after the switching, so as to completely reduce cylinder operation. By slightly decreasing the torque generated by the cylinder to be deactivated and gradually increasing the amount of retardation of the hindlimb ignition timing, the torque generated by the cylinder to be deactivated is gradually reduced, and finally the torque generated by the cylinder to be deactivated is completely reduced. All you have to do is pause it.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a cylinder number control engine equipped with an ignition timing control device according to an embodiment of the present invention, Figure 12 is a flowchart of ignition timing control according to the present invention, and Figure 3 is a set of cylinder number control flags. , reset state,
The time chart showing the relationship between the retard amount and the torque value is an electric circuit diagram showing the main part of the ignition timing control of the present invention. E・・・・・・・・・Engine, EO・・・・・・・
...Outer cylinder, El...Inner cylinder, 4m+4tz4e+4d...Fuel injection valve, 7...Throttle opening sensor, 8...
・・・・・・Control circuit, 10・・・・・・・・・
Torque sensor, 11m, 11b, lie, lid
・−・・−・・Spark plug patent applicant Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] In a cylinder number control engine ignition timing control device that stops combustion in a specific cylinder and operates the remaining cylinders in a specific operating state, when switching from reduced-cylinder operation to all-cylinder operation, or from all-cylinder operation to reduced-cylinder operation, A number-of-operating-cylinder detector detects when switching to operation and generates a switching signal, and when receiving the switching signal, controls to gradually change the ignition retard amount of the cylinder to be stopped or restored. An ignition timing control device for an engine with a controlled number of cylinders, characterized in that an ignition retardation amount controller is provided.