JP2003113718A - Intake passage control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a deterioration in operability at idling caused by an individual difference between a pair of intake throttle valves. SOLUTION: An intake passage control device for an engine comprises intake collectors 4 and 5 independent on a cylinder group basis, the intake throttle valves 8 and 9 independent of cylinder group basis and capable of regulating intake air introduced into corresponding intake collectors, a first communicating passage 18 interconnecting the independent intake collectors, an on-off valve 19 for connecting and disconnecting the first communicating passage, and a first on-off valve controlling means 21 for closing the on-off valve 19 when engine speed is not higher than a first predetermined changeover speed and opening the on-off valve 19 when the engine speed exceeds the first changeover speed. A second on-off valve controlling means 21 is provided to open the on-off valve 19 at idling independently of the first on-off valve controlling means 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine intake passage control device.

[0002]

2. Description of the Related Art An independent intake collector is provided for each of the two cylinder groups, a partition wall that separates the two intake collectors is communicated, and an opening / closing valve is provided in the communication hole so that the engine rotation speed is lower than the switching rotation speed. The on-off valve is fully closed and each intake collector is made independent to obtain the resonance supercharging effect to improve the full load torque in the low and medium rotation speed range. On the other hand, when the engine rotation speed exceeds the switching rotation speed, it opens and closes. Some open the valve fully (see Japanese Utility Model Publication No. 4-8304).

[0003]

By the way, in the above-mentioned conventional apparatus, the intake throttle valve is provided for each of the two cylinder groups corresponding to the independent intake collector. Even if the pair of intake throttle valves have the same structure, the individual difference in the air flow rate flowing through each intake throttle valve becomes large at the time of idling when the air flow rate is the smallest. That is, even when the same command value is issued from the control device to the pair of intake throttle valve actuators at the time of idling, variation occurs in the air flow rate flowing through each intake throttle valve, and due to this variation, the generated torque differs for each cylinder group, Due to this, rotation fluctuations occur (see the solid line in FIG. 6), which causes vehicle body vibrations and deteriorates drivability during idling.

Therefore, an object of the present invention is to prevent deterioration of drivability during idling due to individual differences between a pair of intake throttle valves by opening the opening / closing valve during idling even in a low / medium speed range. .

[0005]

SUMMARY OF THE INVENTION A first aspect of the present invention adjusts a plurality of cylinder groups, an independent intake collector for each cylinder group, and an independent intake air introduced to a corresponding intake collector for each cylinder group. A possible intake throttle valve, a first communication passage that connects the independent intake collectors, an open / close valve that connects and disconnects the first communication passage, and an engine rotation speed that is less than or equal to a predetermined first switching rotation speed. An intake air passage control device for an engine, comprising: an opening / closing valve first control means that closes the opening / closing valve and opens the opening / closing valve when the engine rotation speed exceeds the first switching rotation speed. No. 1 control means, and an on-off valve second control means for opening the on-off valve.

According to a second aspect of the invention, in the first aspect of the invention, a large-capacity intake collector separate from the independent intake collector, and a second series connecting the large-capacity intake collector and the independent intake collector. The passage, the collector capacity switching valve that connects and disconnects the second communication path, the independent intake collector and the large-capacity intake collector are used when the engine rotation speed is equal to or lower than a predetermined second switching rotation speed. Collector capacity switching valve control means for shutting off by the collector capacity switching valve and communicating with the collector capacity switching valve when the engine speed exceeds the second switching speed.

According to a third aspect of the invention, in the second aspect of the invention, the second switching rotation speed is matched with the first switching rotation speed.

[0008]

When the on-off valve is closed even during idling when the air flow rate is the smallest, the air flow rate flowing through each intake throttle valve varies due to the individual difference in the air flow rate flowing through each intake throttle valve. The rotation fluctuation occurs due to the difference in the torque of each cylinder group due to the variation (see the solid line in FIG. 6), which causes the vehicle vibration and deteriorates the drivability at the time of idling. According to the second and third aspects, at the time of idling, the on-off valve is opened and the independent intake collectors are connected by the communication passage. As a result, since air flows between the independent intake collectors, the pressure in one intake collector becomes the same as the pressure in the other intake collector even if the flow rate of air passing through each intake throttle valve is different, and therefore The flow rate of air sucked into the combustion chamber of each cylinder from each intake collector becomes constant.

As described above, in the first, second and third inventions,
Since it is possible to reduce the variation in the air flow rate between the intake collectors at the time of idling when the air flow rate is small, it is possible to suppress the variation in the generated torque between the cylinder groups, thereby improving the stability of idle rotation (FIG. 6). See the dashed line).

When the engine speed is in the low speed range exceeding the idle speed, the on-off valve is closed and the intake collector is independent for each cylinder group, so that the pressure waves generated in each intake collector interfere with each other. From being avoided,
The resonance supercharging effect of the intake air is sufficiently obtained, and the full load performance in the low rotation speed range is improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 showing the configuration of the first embodiment, a first cylinder group consisting of # 1, # 3, and # 5 cylinders respectively provided in a pair of banks of a V-type 6-cylinder engine 1; With the second cylinder group consisting of 2, # 4, and # 6 cylinders, the ignition timings of the respective cylinders of the respective cylinder groups are not continuous, and the opening timings of the intake valves do not overlap (hence no intake interference). It is in.

The intake ports of the cylinders of the first cylinder group and the second cylinder group are opened on the inner wall of the bank. Each branch intake passage 2 connected to each intake port opening of the first cylinder group,
Each branch intake passage 3 is connected to the side wall of the intake collector 4 whose upstream end is horizontally arranged above the cylinder bank and is connected to each intake port opening of the second cylinder group.
The upstream end thereof is connected to and connected to the side wall of the intake collector 5 which is horizontally arranged above the cylinder bank.

Throttle chambers 10 and 11 having intake throttle valves 8 and 9 driven by electric signals from a control device 21 are provided at the front ends of the intake collectors 4 and 5, respectively.
, And the throttle chambers 10 and 11 are connected to one surge tank 14 via connecting members (not shown). Surge tank 14 orthogonal to the cylinder row
An intake pipe 15 is connected to the front wall of the device, and an air cleaner (not shown) is connected to an upstream end of the intake pipe 15 via an air flow meter 16.

Here, the intake passage connecting the one intake collector 4 to the surge tank 14 and the intake passage connecting the other intake collector 5 to the surge tank 14 have the same length.

A communication passage 18 that connects the two intake collectors 4 and 5 is provided near the front ends of the intake collectors 4 and 5, and an opening / closing valve 19 that connects and disconnects the communication passage 18 is provided.

A fuel injection valve 20 is attached to each of the branch intake passages 2 and 3 of each cylinder.

The control device 2 in which the signal of the intake air flow rate from the air flow meter 16 is input together with the signals from the engine speed sensor 22, the accelerator sensor 23 and the like.
In 1, the accelerator opening (accelerator pedal depression amount)
And controlling the opening of the pair of intake throttle valves 8 and 9 and the fuel injection amount from the fuel injection valve 20 for each cylinder so that a target engine torque corresponding to the engine rotation speed can be obtained.
Engine rotation speed and switching rotation speed (first switching rotation speed)
In comparison, the open / close valve 19 is fully closed in the low / medium rotation speed range below the switching rotation speed, whereas the opening / closing valve 19 is fully opened in the high rotation speed range above the switching rotation speed.

Further, during idling when combustion becomes unstable, idle speed control is performed by increasing or decreasing the opening of the pair of intake throttle valves 8 and 9 so that the actual engine speed matches a preset target value. And the opening / closing valve 19 is opened during this idling.

The control of the on-off valve 19 executed by the control device 21 (first on-off valve control means and second on-off valve control means) will be further described with reference to the flow chart of FIG. 3. The flow of FIG. Every 10 ms).

In FIG. 3, in step 1, the engine rotation speed Ne is read from the rotation speed sensor 22, and this is compared with the switching rotation speed (for example, 2800 rpm) in step 2. When the engine rotation speed is equal to or lower than the switching rotation speed, the process proceeds to step 3 to check whether the engine is idle. If it is idle, the routine proceeds to step 4, where the on-off valve 19 is opened. When the rotational speed range exceeds the idling time, the routine proceeds from step 3 to step 5 where the on-off valve 19 is fully closed to obtain the resonance supercharging effect of intake air as in the conventional device.

On the other hand, when the engine rotation speed exceeds the switching rotation speed, the routine proceeds from step 2 to step 6, and at this time, the opening / closing valve 19 is opened as in the conventional device.

The operation of this embodiment will be described below.

The flow rate of the air sucked from the air cleaner is measured by the air flow meter 16 and then the intake pipe 1
5 and flows into the surge tank 14. Then, from here, it is distributed from each branch intake passage 2 to the combustion chamber of each cylinder of the first cylinder group via the connecting member, one intake passage formed of the throttle chamber 10 and one intake collector 4, and the connecting member, It is distributed from each branch intake passage 3 to the combustion chamber of each cylinder of the second cylinder group via the other intake passage formed of the throttle chamber 11 and the other intake collector 5.

On the other hand, the fuel injection amount is calculated by the controller 21 based on the intake air amount measured by the air flow meter 16 so that a predetermined target equivalent ratio is obtained.
This fuel injection amount is injected and supplied from the fuel injection valve 20 of each cylinder at a predetermined timing.

In this case, when the throttle actuator (not shown) is driven in response to the depression of the accelerator pedal to open the pair of intake throttle valves 8 and 9, the intake passage between the surge tank 14 and one intake collector 4 is opened. And the length of the intake passage between the surge tank 14 and the other intake collector 5 are set to be the same, so that the natural frequencies of the air columns in the respective passages become equal, whereby the first cylinder Intake air is supplied to the group and the second cylinder group substantially in the same manner.

Now, when the engine rotational speed is in the low / medium rotational speed region below the switching rotational speed of 2800 rpm, the on-off valve 19 is fully closed. The pressure change in the intake collector becomes larger than when the on-off valve 19 is open (see the solid line in FIG. 4), which causes the resonance supercharging effect, so that the full load torque can be improved as shown in FIG.

However, even if the pair of intake throttle valves 8 and 9 have the same structure, the individual differences in the air flow rates flowing through the intake throttle valves 8 and 9 become large at the time of idling when the air flow rate is the smallest. That is, even when the same command value is issued from the control device 21 to the pair of throttle actuators at the time of idling, variations occur in the air flow rate flowing through the intake throttle valves 8 and 9, and due to this variation, the torque generated varies among the cylinder groups. Occurs, which causes rotation fluctuation (see the solid line in FIG. 6), which causes deterioration of drivability at the time of idling. In the present embodiment, in the low / medium rotation speed range below the switching rotation speed. However, at the time of idling, the on-off valve 19 is opened and the two intake collectors 4, 5 are connected by the communication passage 18.

As a result, since air flows back and forth between the intake collectors 4 and 5, even if the flow rates of the air passing through the intake throttle valves 8 and 9 are different, the pressure in one intake collector 4 and the other intake collector 5 are different. Since the internal pressure becomes the same, the flow rate of the air drawn from each intake collector 4, 5 into the combustion chamber of each cylinder via the branch intake passages 2, 3 becomes constant, and a difference occurs in the generated torque for each cylinder group. It is difficult (see the chain line in FIG. 6). As a result, the stability of idle rotation is improved.

The engine rotation speed is the switching rotation speed 2
In the high rotation speed range over 800 rpm, the on-off valve 19 is opened, and the intake air of all the cylinders is supplied to the two intake collectors 4, 5.
Meet in an open space. At this time, it becomes the same as the normal case where there is only one intake collector, and the same torque as in the normal case is obtained (see FIG. 5).

7 and 8 show a second embodiment, which replaces FIGS. 1 and 2 of the first embodiment. This embodiment is premised on a switchable intake collector volume. That is, two independent intake collectors 4, 5
Large capacity intake collector 31 with a certain distance above the
Are arranged, and the large-capacity intake collector 31 and the two intake collectors 4 and 5 are provided in a plurality (four in the figure) of the communication passage 3.
A collector capacity switching valve 33 is provided which is connected via 2 and connects / shuts off each of the four communication passages 32 under the same conditions as the on-off valve 19 in response to a signal from the control device 21.

Note that, in FIG. 7, the central portion of the intake collector 31 is drawn through, and it is difficult to see, so the drawing of the fuel injection valve is omitted.

According to such an intake passage device, when the engine rotation speed exceeds the switching rotation speed of 2800 rpm, in addition to opening the on-off valve 19, all four collector capacity switching valves 33 are fully opened, and the two collectors 4, By connecting 5 to the large-capacity collector 31 via the four communication passages 32, the full-load performance at high engine speed can be improved (see the alternate long and short dash line in FIG. 9).

As shown in FIG. 9, the switching rotational speed for connecting the large-capacity collector 31 and the intake collectors 4, 5 to each other depends on the engine torque of the resonance supercharging effect due to the two collectors and the large-capacity one collector. By setting the rotation speed at which the engine torque of the intake inertia effect becomes equal, the maximum effect of improving the torque in the entire rotation speed range can be obtained.

The engine speed is 2800 rpm.
4 collector capacity switching valves 3 in the following low / medium speed range
If all 3 are fully closed, it becomes the same as the case where the large-capacity intake collector 31 is not provided (that is, the same as the first embodiment).

Therefore, even in such an intake passage device,
A communication passage 18 that connects the two intake collectors 4 and 5 is provided near the front ends of the intake collectors 4 and 5, and an on-off valve 19 that connects and disconnects the communication passages 18 is provided, respectively, and the engine rotation speed is higher than 2800 rpm. While the on-off valve 19 is opened in the rotation speed range, the engine rotation speed is 280
When the low / medium speed range of 0 rpm or less is reached, this on-off valve 1
When 9 is fully closed, the resonance supercharging effect can be obtained and the torque at full load can be improved.

Further, the stability of idle rotation can be improved by opening the on-off valve 19 fully only during idling.

In the embodiment, the V-type engine is divided into two cylinder groups for each bank, and the independent intake collector is arranged corresponding to each cylinder group. However, the present invention is not limited to this, and it is not limited to this. The present invention can be applied to a case where the engine is divided into two cylinder groups and independent intake collectors are arranged corresponding to the respective cylinder groups. Further, the number of cylinder groups is not limited to two.

In the second embodiment, the case where the collector displacement switching valve is switched at the switching rotation speed of the on-off valve (first switching rotation speed) has been described, but the rotation speed at which the collector capacity switching valve is switched (second switching rotation speed) is It does not have to be the same as long as it is equal to or higher than the first switching rotation speed at which the torque improvement effect at a high rotation speed can be obtained by switching to the large capacity collector.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a configuration of an engine having an independent intake collector according to a first embodiment.

FIG. 2 is a schematic elevational view of an engine also having an independent intake collector.

FIG. 3 is a flowchart for explaining control of an opening / closing valve.

FIG. 4 is a waveform diagram showing changes in collector internal pressure when the on-off valve is opened and when it is closed.

FIG. 5 is a characteristic diagram of engine torque according to the first embodiment.

FIG. 6 is a waveform diagram showing each rotation fluctuation during idling when the on-off valve is opened and closed.

FIG. 7 is a schematic plan view showing the configuration of an engine having an independent intake collector according to the second embodiment.

FIG. 8 is a schematic elevational view of an engine also having an independent intake collector.

FIG. 9 is a characteristic diagram of engine torque according to the second embodiment.

[Explanation of symbols]

4, 5 intake collector 18 communication passages (first communication passage) 19 open / close valve 21 Control device 31 Large intake collector 32 communication paths (second communication path) 33 Collector capacity switching valve

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Claims (3)

[Claims] 1. A plurality of cylinder groups, an intake collector that is independent for each cylinder group, an intake throttle valve that is independent for each cylinder group, and is capable of adjusting intake air introduced into a corresponding intake collector, and the independent intake collector. A first communication passage that connects between the intake collectors, an opening / closing valve that connects and disconnects the first communication passage, and the opening / closing valve is closed when the engine rotation speed is equal to or lower than a predetermined first switching rotation speed to rotate the engine rotation. Speed is the first
An on-off valve control device for an engine, comprising: an on-off valve first control means for opening the on-off valve when the switching speed exceeds a switching speed. An on-off valve second for opening the on-off valve regardless of the on-off valve first control means during idling. An intake passage control device for an engine, comprising: a control means. 2. A large-capacity intake collector separate from the independent intake collector, a second communication passage connecting the large-capacity intake collector and the independent intake collector, and the second communication passage. A collector capacity switching valve that connects and disconnects, and the independent intake collector and the large capacity intake collector are shut off by the collector capacity switching valve when the engine speed is equal to or lower than a predetermined second switching speed. The intake passage control device for the engine according to claim 1, further comprising: a collector displacement switching valve control unit that communicates with the collector displacement switching valve when the rotation speed exceeds the second switching rotation speed. 3. The intake passage control device for an engine according to claim 2, wherein the second switching rotation speed is matched with the first switching rotation speed.