JPH0350907B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine, more specifically, an ignition timing system for an engine in which the substantial passage shape of the intake system of the engine is made variable depending on the operating condition. This relates to a control device.

(Prior Art) In addition to superchargers such as turbochargers, supercharging using dynamic effects such as the inertia effect, pulsation effect, and resonance effect of the intake air is known as a means for increasing the filling efficiency of intake air into the engine. These supercharging effects are generally limited in the area in which they can be effectively obtained due to constraints on the characteristics of the supercharger and the shape of the intake passage.

For this reason, in engines, especially automobile engines, by changing the actual shape of the passage in the intake system depending on the operating conditions, it is possible to expand the area where supercharging effects can be obtained or to improve the effect in a limited area. Some devices are known that provide an effective supercharging effect.

Here, as a means to change the shape of the intake passage,
As seen in Japanese Utility Model Application Publication No. 56-105626, changing the length of the intake pipe, providing a volume in the intake passage,
Means such as changing the volume of the volume provided in the intake passage or changing the diameter of the intake passage have been proposed, and in this type of engine, generally,
A switching valve is disposed in the intake system, and the intake system is variably controlled by opening and closing the switching valve depending on the operating state.

In other words, the shape of the passage in the intake system is changed by controlling the opening and closing of the switching valve, thereby expanding the area where the supercharging effect can be obtained or obtaining an effective supercharging effect in a limited area. be.

Therefore, in this type of engine, the intake characteristics will change rapidly after the switching of the switching valve, and the required advance angle of the ignition timing will also change rapidly accordingly. .

In contrast, conventional ignition timing control for this type of engine involves, for example, setting multiple ignition timings based on the required advance angle, and determining the target ignition timing for each operating state by an interpolation method based on adjacent setting values. It was supposed to be done.

(Problems to be Solved by the Invention) However, with conventional control, it is difficult to obtain ignition timing control characteristics that correspond to the sudden change in the required ignition timing after the switching point of the switching valve.
In the switching region of the switching valve, there is a problem in that the target value is far from the required advance angle.

The present invention has been made in view of the above problems, and its technical problem is an ignition timing control device for an engine that optimizes ignition timing control in an operating range in which the switching valve is switched. The purpose is to provide

(Means and actions for solving the problem) In order to achieve the above technical problem, the present invention provides a switching valve that is disposed in the intake system of the engine and is controlled to open and close according to the operating state. As shown in FIG. The required ignition timing under the intake system passage shape when the valve is opened is set as data, and in the valve closing region where the switching valve is closed, the required ignition timing under the intake system passage shape when the switching valve is closed is set as data. A map in which the required ignition timing of the switching valve is set as data, and when transitioning from the valve open region to the valve closed region in synchronization with the opening/closing control of the switching valve, the required ignition timing in the valve open region in the map is set. When changing the data to the hypothetical required ignition timing when the switching valve is closed in the valve-opening region, and transitioning from the valve-closing region to the valve-opening region,
ignition control characteristic changing means for changing required ignition timing data in the valve closing region in the map to virtual required ignition timing when the switching valve is opened in the valve closing region; and the ignition control characteristic changing means. target ignition timing determining means for determining a target ignition timing according to the operating condition by linear interpolation based on a map whose data has been changed by; The configuration includes ignition control means for igniting the ignition plug at the appropriate timing.

(Example) Hereinafter, regarding an example of the present invention, two groups of cylinders whose intake strokes are not consecutive are connected to each other through independent passages.
An example of an engine in which independent surge tanks in the intake system are connected to two surge tanks, each connected to an independent passage acting as a resonance pipe upstream of the surge tank, and communicated with each other depending on the rotation speed, will be explained based on drawings. .

In FIG. 2, 1 is an engine body, and the engine body 1 has a combustion chamber 6 defined by a cylinder head 2 and a piston (not shown) fitted into a cylinder block (not shown). 6 has an intake port 8 and an exhaust port 10 opened, the intake port 8 is provided with an intake valve (not shown), and the exhaust port 10 is provided with an exhaust valve (not shown). There is.

The intake system 12 of the engine body 1 connected to the intake port 8 has two independent passages 13a downstream of an air cleaner (not shown), which are sequentially arranged from the upstream side.
The independent passages 13a, 13b are each provided with a throttle valve 14, and the independent passages 13a, 13b communicate with independent surge tanks 16a, 16b, respectively.
a and 16b communicate with cylinder groups that are not adjacent to each other in the intake stroke through independent passages 17, respectively. Further, the surge tanks 16a and 16b are defined by a partition wall 18, and communication is controlled by a switching valve 24 provided on the partition wall 18.

That is, when the switching valve 24 is closed, the independent passage 13
a, 13b act as resonance pipes, while an inertial effect is created between the surge tanks 16a, 16b and each intake port 8 when the switching valve 24 is open. Therefore, the intake system 15 has two vibration systems by switching the switching valve 24, and by using these two vibration systems, the switching valve 24 can be closed in the low rotation speed range and the high rotation speed range. Supercharging is obtained by the resonance effect of the intake air, while supercharging is obtained by the inertia effect of the intake air in the short passage 17 (when the switching valve 24 is open) in the medium rotation speed range. From this, as shown in Fig. 3, a torque curve shown by a solid line is obtained in the low engine speed range (Ne<N ₁ ) where the engine speed (Ne) is low, and in the middle engine speed range (N ₁
<Ne), a torque curve shown by a broken line is obtained, and ignition timing control corresponding to this is required. In addition, in FIG. 3, the torque curve in the high rotation range is omitted.

To briefly explain the ignition timing control in the present invention, as a target ignition timing determining means,
As shown in Fig. 4, there is a basic ignition timing map (hereinafter referred to as the basic IG map) divided by engine speed and throttle opening. The required lead angle at 2500γpm, the required lead angle X2 at 13000γpm, etc. are set, and this setting value 1,
X2 and the like are appropriately changed in synchronization with the switching of the switching valve 24 to determine the target ignition timing.

In addition, the change value to be replaced with the above set value is the virtual required advance angle when the switching valve 24 is closed in the low rotation speed range (Ne<N ₁ ), for example, x in FIG.
1, and in the middle rotation speed range (N ₁ < Ne < N ₂ ), the virtual required advance angle when the switching valve 24 is opened is set to a value of 2 in FIG. When changing the data of the above setting values ・1 and ×2, when the engine operating condition is in the low speed range, the engine speed
The set value x 2 at 3000γpm is changed to 2. This constitutes an ignition control characteristic changing means that changes the ignition timing control characteristic to an ignition timing control characteristic corresponding to the requested ignition timing in accordance with the opening and closing of the switching valve 24.

The target ignition timing between the engine speed of 2500 γpm and the switching point _N1 of the switching valve 24 is determined by the set value x 1, which is the required advance angle when the switching valve 24 is closed, and the change value x 2. determined by linear interpolation based on Conversely, when the engine speed is in the medium speed range, the setting value at engine speed 2500γpm x 1
The data was changed to ・1 and ×2 to ・2, and the target ignition timing between switching point N ₁ and 3000γpm is the changed value ・ which is the required advance angle when the switching valve 24 is opened. 1 and the set value 2.

Below, the content of ignition timing control in the present invention will be explained in detail based on a flowchart.

First, the switching valve 24 is opened and closed by an actuator 28 operated by an output signal from the control unit 26, and as shown in _FIG .
In the high rotation speed range (Ne>N ₂ ), the switching valve 24 is closed, and in the middle rotation speed range (N ₁ <Ne<N ₂ ), the switching valve 24 is opened. The operating range of the switching valve 24 is such that the switching operation is performed when the load is above a predetermined load, and it is always open when the load is below the predetermined load.

The control unit 26 also receives an engine speed signal from the rotation speed sensor 30, and based on this engine speed signal, controls the first rotation that is turned off when the engine speed (Ne) is N1 _or more. A few switches (NSW1) and the engine speed changes.
A second rotation speed switch (NSW ₂ ) is provided, which is turned OFF when N ₂ or more, and an injection amount switch (TPSW) is provided, which is turned OFF when the injection amount of the injector that supplies fuel to the engine is more than a predetermined value. ), and from the control unit 26,
An ignition timing control signal is output to the igniter 32, and the spark plug 34 is ignited. Of course, the ignition of the ignition plug 34 is performed by supplying the ignition plug 34 with a secondary current generated by the igniter 32 cutting off the primary current.

Based on the above, the ignition timing control when switching the switching valve 24 will be explained. First, in step S1, the injection amount switch (TPSW) is turned on (ON).
It is determined whether or not this is the case, and if the fuel injection amount is equal to or greater than the predetermined value, the process proceeds to the next step 2.
Note that when the fuel injection amount is above a predetermined value, that is, when the operating state is below a predetermined load, the switching valve 24 is not switched, so the ignition timing is determined based on the above-mentioned basic IG map.

In step S2 and the next step S3, it is determined whether the rotation speed switches (NSWI, NSW2) are on or off, and whether the switching valve 24 is open or closed is determined. As shown in Fig. 5, both rotation speed switches (NSWI, NSW2) are ON in the low rotation speed range (Ne<N ₁ ), so steps S3 to S4 are performed.
On the other hand, in the middle rotation speed range (N ₁ < Ne < N ₂ ), NSW1 is off (OFF) and NSW2 is on (ON), so step S3 to step S5
In the high rotation speed range (N ₂ < Ne), NSW2
is off (OFF), the process advances from step S2 to step S4. That is, in the region where the switching valve 24 is closed, the process proceeds to step S4, and in the region where the switching valve 24 is open, the process proceeds to step S5. and,
In step S4 and step S5 above, the basic
The setting value data on the IG map is changed.

In step S4, the switching valve 24 is closed, that is, in the low rotational speed region (Ne<N ₁ ) or the high rotational speed region (N ₂ <Ne), so the data in the relevant region is set as the set value ×1, ×4. Then, on the other hand, the data is changed to change the set value ・2, ・2 in the middle rotation speed range (N ₁ < Ne < N ₂ ) to the changed value x 2, x 3, and in the next step S6, the set value x 1 The target ignition timing is determined by linear interpolation based on the change value x 2 or the set value x 4 and the change value x 3. In other words, when switching from the medium rotation speed range to the low rotation speed range or high rotation speed range and switching to close the switching valve 24, the data in each range is transferred to the switching valve 24 in synchronization with this switching. The target ignition timing is determined based on the control characteristics at a value corresponding to the required advance angle when the valve is closed. Therefore, the switching valve 2
The ignition timing control characteristic of the switching region 4 (the side with the switching point) can be made to match the required ignition timing.

On the other hand, in step S5, the switching valve 24 is open, that is, in the middle rotation speed range (N ₁ < Ne < N ₂ ), so the data in this area is set to the set values ・2, ・3, and the data in the low rotation speed region The data is changed so that the data at (Ne<N ₁ ) is the change value 1, and the data in the high rotation speed range (N ₂ <Ne) is the change value 4.
In step S6, the target ignition timing is determined by linear interpolation based on the change value 1 and the set value 2 or the set value 3 and the change value 4. In other words, when the changeover valve 24 is switched to the middle rotation speed range, in synchronization with this switching, based on the control characteristics at a value corresponding to the required advance angle when the switch valve 24 is opened, The target ignition timing is determined, and the ignition timing control characteristics in the switching region of the switching valve 24 can be made to match the required ignition timing. Then, in step S7, an ignition timing control signal is output to the igniter 32 based on the target ignition timing determined in step S6.

Although one embodiment of the present invention has been described above, the above-mentioned dual injection switch (TPSW) may be replaced with a throttle opening sensor or the like capable of detecting a load exceeding a predetermined value. Furthermore, as a means for synchronizing the switching of the switching valve 24 and the above data change, an output signal from an engine rotation speed sensor or an opening/closing control signal for the switching valve 24 may be used. Furthermore, means for changing the shape of the engine intake passage are not limited to the embodiments, but may include changing the length of the intake pipe, changing the volume of the volume provided in the intake passage, changing the diameter of the intake passage, or changing the diameter of the intake passage. As shown in Japanese Utility Model Application Publication No. 105626/1983, this includes those in which the shape of the intake passage is changed by a switching valve in response to supercharging by a supercharger.

(Effects of the Invention) As is clear from the above description, according to the present invention, in a device provided with a switching valve that changes the substantial passage shape of the intake system, the valve opening region is adjusted in synchronization with switching of the switching valve. When transitioning from the valve closing region to the valve closing region, all data in the map is the required ignition timing when the switching valve is closed, and when transitioning from the valve closing region to the valve opening region, all the data in the map is set to the required ignition timing when the switching valve is closed. Since this is the required ignition timing when the valve is opened, in the switching region where the switching valve is controlled to open and close, the continuity of the data that is the basis for determining the ignition timing by linear interpolation is ensured, and therefore the switching It becomes possible to optimize ignition timing control in this region.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of the present invention, Fig. 2 is an overall system diagram in an embodiment of the present invention, Fig. 3 is a diagram showing the relationship between the switching of the switching valve and the torque curve, and Fig. 4 is the target ignition. An ignition timing control map used for timing determination, FIG. 5 is a diagram showing the relationship between switching of the switching valve and required ignition timing, and FIG. 6 is a flowchart showing one control example of the present invention. DESCRIPTION OF SYMBOLS 1...Engine main body, 15...Intake system of the engine, 24...Switching valve provided with the intake system, 26...
...Control unit, 32...Igniter,
34...Spark plug.

Claims (1)

[Claims] 1. A switching valve is disposed in the intake system of the engine and is controlled to open and close depending on the operating state, and the substantial passage shape of the intake system can be varied by opening and closing the switching valve. In the engine configured as shown in FIG. In the valve region, there is a map in which the required ignition timing under the shape of the passage of the intake system when the switching valve is closed is set as data, and a map in which the required ignition timing is set as data under the shape of the passage of the intake system when the switching valve is closed. When moving to the valve region, the required ignition timing data in the valve open region in the map is changed to the virtual required ignition timing when the switching valve is closed in the valve open region, and the data is changed from the valve closed region to the virtual required ignition timing when the switching valve is closed in the valve open region. When moving to the valve opening region,
ignition control characteristic changing means for changing required ignition timing data in the valve closing region in the map to virtual required ignition timing when the switching valve is opened in the valve closing region; and the ignition control characteristic changing means. target ignition timing determining means for determining a target ignition timing according to the operating condition by linear interpolation based on a map whose data has been changed by; An ignition timing control device for an engine, comprising: ignition control means for igniting a spark plug at the specified timing.