JPH04303123A - Intake control device for engine - Google Patents

Abstract

PURPOSE:To dissolve the shortage of negative pressure in a vacuum chamber during the full acceleration of an engine to secure its accelerating ability through an engine intake control device in which the negative pressure in an intake pipe changes over the route length of an intake passage, and intake inertia effect improves the charging efficiency of the engine. CONSTITUTION:In an intake control device which is provided with a vacuum chamber, and leads the negative pressure in the vacuum chamber into an actuator on the number of revolutions of an engine, and thereby changes over the intake route length, when an engine load is above a fixed value, and the number of revolutions of the engine is below a fixed value, the changing-over of the intake route length is unnecessary, and the above changing in starting the engine is prohibited. When the engine load is above the fixed value, and the changing speed of the number of revolutions of the engine in its lowering direction is above a fixed value, the changing-over of the intake route length is prohibited. In addition to that, the engine having an automatic gear is provided with a detecting means for brake actuation, and when the brake is working, and the engine load is above the fixed value, the changing-over of the length of the intake route is prohibited.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is an engine in which the length of the intake passage, that is, the actual length of the intake passage, is switched by driving the opening/closing control valve using intake pipe negative pressure. This invention relates to improvements in intake control devices.

0002

[Prior Art] Conventionally, various methods have been proposed for increasing the output by improving the filling efficiency of intake air in engines for vehicles such as automobiles. By providing a passage and switching the intake passage by opening and closing a control valve provided in the passage, the intake passage can be set substantially short in the high engine speed range, while
In the low engine speed range, the intake passage is set to be substantially longer, thereby increasing the dynamic effect of the intake air throughout the entire engine speed range.
That is, there are known devices equipped with an intake air control device that enhances the intake inertia effect and improves the filling efficiency.

Conventionally, this type of engine intake control device has been provided with a vacuum chamber for storing intake pipe negative pressure, and the negative pressure of the vacuum chamber is applied to an actuator, as shown in, for example, Japanese Utility Model Application Publication No. 1-159126. The control valve is driven to open and close by introducing the control valve.

0004

[Problems to be Solved by the Invention] On the other hand, it is known that multi-cylinder engines have a structure in which cylinders that do not operate in consecutive order are grouped together and divided into two groups, and both cylinder groups are arranged in a V-shape with respect to each other. It is being When an engine with such a structure is equipped with the above-mentioned intake control device, a surge tank is provided for each cylinder group, the surge tank and each cylinder are connected through an intake passage, and the surge tanks are connected to each other by a first ，
A control valve is provided in each of the first and second communication paths, and the opening/closing points of both control valves are set at different engine speeds, for example, as shown in FIG. 4(b). It is conceivable to control opening and closing individually in a pattern. here,
The shaded area in FIG. 4 indicates the closed state of the control valve, and each control valve is set to be switched from the closed state to the open state by introducing negative pressure to the actuator.

By the way, in an engine equipped with an automatic transmission, if the throttle valve is fully open, the engine speed is automatically changed while the engine speed is increasing in a predetermined engine speed range, and the engine speed temporarily decreases, which is a so-called stall. It is known that rotation occurs. This stall rotation occurs in a relatively low rotation range (see Fig. 4(b)), and when this phenomenon occurs, both control valves, which were once opened at engine speed Ne1 or higher, become lower than engine speed Ne1. It is closed as the rotation speed decreases to Ne1, and then reopened when the rotation speed rises above Ne1. As a result, negative pressure is introduced into the actuator twice in total by the two control valves. . Furthermore, when the transmission is shifted up in a relatively high speed range with the throttle valve fully open, at the time of this shift up, the engine speed is reduced to N, for example in FIG. 4(b).
After once decreasing from e5 or more to near Ne3, the rotational speed increases again. Therefore, negative pressure is introduced into the actuator three times in total for both control valves (two times for VRIS1 and once for VRIS2). Therefore, for example,
When the vehicle is fully accelerated from a stopped state to a speed of about 60 miles/hour, both of the control valves described above are operated a total of seven times.

However, with the engine intake control device described above, the negative pressure in the intake pipe becomes approximately 1 atm during full throttle acceleration, making it impossible to additionally introduce sufficient negative pressure into the vacuum chamber.
Moreover, due to the layout within the engine room, the volume of the vacuum chamber is limited, and while the capacity to operate the control valve 7 times is required, only a vacuum chamber with a capacity to operate the control valve 5 times can be installed. Therefore, in the high rotation and high load region before the desired speed (60 miles/Hr) is reached, there is a problem in that the negative pressure in the vacuum chamber is insufficient, resulting in poor acceleration.

[0007] In view of these problems, the present invention aims to improve the intake air filling efficiency during normal operation, while ensuring acceleration performance during full throttle acceleration by reliably and appropriately switching the intake path length. The purpose of the present invention is to provide an intake control device for an engine.

[0008]

[Means for Solving the Problems] Therefore, an engine intake control device according to the present invention includes a vacuum chamber for storing intake pipe negative pressure, and introduces the negative pressure of the vacuum chamber to an actuator based on the engine rotation speed. Therefore, in an engine intake control device that switches the intake path length, even if the intake path length is originally in the rotation range where the intake path length should be switched, if the output is not required so much, the intake path length is changed. The gist is that switching the route length is prohibited.

[0009] Here, even if the intake path length is originally in the rotation range where the length should be changed, the output is not required so much, such as at the start of a start, when shifting up during full throttle acceleration, or when using an engine with an automatic transmission. Refers to the beginning of a full throttle start, etc.

That is, in the above-mentioned intake control device, the start time is determined by detecting a state in which the engine load is above a predetermined value and the engine speed is below a predetermined value;
When this is determined, switching of the intake path length based on the engine speed is prohibited.

[0011] Furthermore, in the above-mentioned intake control device, by detecting a state in which the engine load is above a predetermined value and the rate of change in the downward direction of the engine speed is above a predetermined value, it is possible to determine when to shift up during full-throttle acceleration. , when this is determined, switching of the intake path length based on the engine speed may be prohibited.

Furthermore, the above-mentioned intake control device is provided with an automatic transmission that automatically switches the gear range, and is also provided with means for detecting the operation of the brake, and detects a state in which the brake is being applied and the engine load is above a predetermined value. By doing so, it is possible to determine when a full throttle start is started in an engine with an automatic transmission, and when this is determined, to prohibit switching of the intake path length based on the engine speed.

[0013]

[Operation] In the present invention, when the engine load is above a predetermined value and the engine speed is below a predetermined value, that is, at the beginning of a start, switching of the intake path length based on the engine speed is prohibited, thereby achieving full throttle acceleration. This eliminates unnecessary switching of the intake path length in the low engine speed range, preventing waste of negative pressure.

[0014] Furthermore, when the engine load is above a predetermined value and the rate of change in the engine speed in the downward direction is above a predetermined value,
In other words, by prohibiting switching of the intake path length based on the engine speed when shifting up during full throttle acceleration, the intake path length can be switched even if the engine speed decreases due to a shift up during full throttle acceleration. This prevents negative pressure from being wasted.

Furthermore, in an engine equipped with an automatic transmission, when the brake is in operation and the engine load is above a predetermined value, switching of the intake path length based on the engine speed is prohibited, so that the so-called Even if there is stall rotation of the automatic transmission, the intake path length is not switched, and waste of negative pressure is prevented.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. 1 to 4 show an engine intake control device according to an embodiment of the present invention. In engine 1, the 1st to 6th 6
The two cylinders are grouped into first and second cylinder groups 2a and 2b, which operate in a non-consecutive order, and both cylinder groups 2a and 2b are arranged opposite to each other in a V-shape to form a V-type six-cylinder engine. is configured. Although not specifically illustrated,
An automatic transmission is connected to the output shaft of the engine 1 to automatically change the gear range.

Further, the engine 1 is provided with first and second surge tanks 3a and 3b extending in the cylinder arrangement direction above the first and second cylinder groups 2a and 2b. The tanks 3a, 3b and each cylinder are connected by an intake manifold (not shown), and one end of an intake pipe 4a, 4b is connected to the surge tank 3a, 3b, respectively. The upstream sides of the intake pipes 4a, 4b are gathered together and connected to a throttle body 5, and a throttle valve 6 that is opened and closed by depression of an accelerator pedal is disposed within the throttle body 5. Further, an intake pipe 7 is connected to the throttle body 5, and an air cleaner 8 is connected to the upstream side of the intake pipe 7.

Between the surge tanks 3a and 3b, a first communication passage 9 with a shorter dimension is connected at approximately the center in the longitudinal direction, and a second communication passage 10 with a longer dimension is connected at one end in the longitudinal direction. The first and second communication passages 9 and 10 are provided with first and second control valves 11 and 12 that open and close them. Diaphragm type first and second actuators 13 and 14 for driving the control valves 11 and 12 are connected to the rotation shafts of the control valves 11 and 12, respectively, and negative pressure is introduced into the negative pressure chambers of the actuators 13 and 14. As a result, the control valves 11 and 12 are opened.

Further, a negative pressure introduction passage 15 is connected to the intake pipe gathering portion 4 on the downstream side of the throttle valve 6, and a check valve 16 is interposed in the middle of the negative pressure introduction passage 15. The other end of the negative pressure introduction passage 15 is a vacuum chamber 17.
The vacuum chamber 17 is connected to the vacuum chamber 17 through the negative pressure introduction passage 15 to introduce and store the negative pressure of the intake pipe collection section 4 .

One end of a negative pressure supply passage 18 is connected to the vacuum chamber 17.
A first negative pressure supply passage 19 is connected in the middle of the first
A three-way valve 20 made of an electromagnetic solenoid valve is interposed in the middle of the negative pressure supply passage 19. One output port of the three-way valve 20 is open to the atmosphere, and the other end of the first negative pressure supply passage 19 is connected to the first actuator 13. When the three-way valve 20 receives the control signal and shuts off the output port and the atmosphere, the negative pressure in the vacuum chamber 17 is transferred to the first
is introduced into the negative pressure chamber of the actuator 13.

The other end of the negative pressure supply passage 18 is connected to a three-way valve 21 consisting of an electromagnetic solenoid valve.
One output port of No. 1 is open to the atmosphere, and the other output port is connected to the second negative pressure supply passage 22. The other end of the second negative pressure supply passage 22 is connected to the second actuator 14, and when the three-way valve 21 receives a control signal and shuts off the output port and the atmosphere, the negative pressure in the vacuum chamber 17 is is introduced into the negative pressure chamber of the second actuator 14 via the negative pressure supply passages 18 and 22.

In FIG. 1, 23 is a rotational speed sensor that detects the engine rotational speed, 24 is a throttle sensor that detects the opening degree of the throttle valve 6, and 25 is a brake sensor that detects the operation of the brake (brake operation detection means). ), and 26 is the intake path length (substantive path length of the intake path)
This is a control unit that switches and controls the The control unit 2
6 inputs signals from the sensors 23 to 25, and operates the first and second three-way valves 20, 20,
By outputting a control signal to 21, the negative pressure in the vacuum chamber 17 is controlled by the first and second actuators 13, 1
4, and the intake path length is switched and controlled in pattern B shown in FIG. 4(b). Furthermore, when the brake is being applied and the engine load is above a predetermined value, the control unit 26 prohibits switching of the intake path length based on the engine speed, and pattern A shown in FIG. Control with.

Next, the operation will be explained using FIGS. 2 to 4. Here, FIG. 2 shows a flow of intake path length switching control, and FIG. 3 schematically shows the switching control process in a hardware configuration to aid understanding. Further, FIG. 4 shows the switching method when prohibiting switching and during normal operation as pattern A and pattern B, and the hatched portion in the figure shows the closed state of the control valves 11 and 12.

During normal operation of the engine 1, the control valves 11 and 12 operate as shown in FIG.
Switching is controlled as shown in pattern B of b). That is,
When the engine speed Ne is less than the first set value Ne1, which is about the idle speed, the control unit 26 does not output a control signal, and the first and second actuators 13, 14
No negative pressure is introduced into the control valves 11 and 12, and the control valves 11 and 12 are closed. Next, when the engine speed Ne becomes equal to or higher than the first set value Ne1, a control signal is output from the control unit 26 to the three-way valves 20 and 21, and the first and second actuators 13,
14 is activated and the control valves 11 and 12 are opened. Thereafter, when the engine speed Ne increases and exceeds the second set value Ne2, the output of the control signal is stopped and the control valves 11, 1
2 is closed. The engine speed Ne further increases,
When the third set value Ne3 is exceeded, a control signal is output to the second three-way valve 21, and when the fourth set value Ne4 is exceeded, a control signal is output to the first three-way valve 20, and the control valves 11 and 12 are output. They will be opened sequentially. Furthermore, when the engine speed Ne exceeds the fifth set value Ne5, the output of the control signal is stopped and the control valves 11 and 12 are closed.

As described above, during normal operation of the engine 1, the control valves 11 and 12 are controlled to open and close according to the rotational speed Ne, and the length of the intake passage is appropriately adjusted, thereby ensuring the intake inertia effect in the entire rotational range. This increases filling efficiency.

On the other hand, 60 miles/H from the vehicle stop state
At the time of full-open start to speed r, the control valves 11 and 12 are switched and controlled based on the engine rotational speed Ne as shown in pattern A in FIG. 4(a). That is, when the engine speed Ne is low, a control signal is output from the control unit 26 to the three-way valves 20 and 21, the first and second actuators 13 and 14 are operated, and the control valves 11 and 12 are opened. Then, the engine speed Ne increases to the first set value Ne.
1 and is maintained in the open state until the second set value Ne2 is reached. The engine speed Ne is the second set value Ne
2, the output of the control signal is stopped and the control valve 11
, 12 are closed, and then, as in the case of pattern B, the second control valve 12 is set to the third set value Ne3 and the fourth set value Ne
4, the first control valves 11 are respectively opened and the fifth set value N
When e5 is exceeded, the control valves 11 and 12 are closed. In this way, when starting at full throttle, switching in the low rotation range where much output is not required is prohibited.

As a result, in the control method of pattern B, stall rotation peculiar to automatic transmissions occurs while the engine speed Ne is increasing, and when the engine speed Ne falls below the first set value Ne1 and increases again. In addition, the control valve 11, which is not originally necessary,
However, in the control method of pattern A, even if stall rotation occurs, the control valves 11 and 12 are kept open as in the idle region, so the control valve 11 , 12 is required to be switched two times less in total than during normal operation. Therefore, the negative pressure in the vacuum chamber 17 is not wasted.

Next, the switching control processing in the control unit 26 will be explained in detail.

In the switching control process, as shown in FIG. 2, it is first determined whether the brake switch 25 is turned on (step S20), and if it is turned on, the throttle opening TVO From the comparison between the engine load and the set value, it is determined whether the engine load is equal to or higher than a predetermined value (step S22). Further, when the brake switch 25 is OFF, it is determined whether a predetermined time has elapsed since the brake switch 25 was turned OFF from ON (step S21).

If the engine load is above a predetermined value and if it is within a predetermined time since the brake switch 25 was turned off, it is determined that a full throttle start has begun, and the process of pattern A is performed (step S24). On the other hand, if the engine load is less than the predetermined value and the brake switch 25
If a predetermined period of time has passed since the switch was turned OFF, it is determined that the time to start at full throttle has passed, and pattern B is activated.
The following process is performed (step S23).

That is, to explain in terms of the hardware configuration using FIG. 3, the detection circuit 50 compares the throttle opening degree TVO with a set value to detect full-open acceleration, and its output is
The detection circuit 51 is input to one input terminal of the D circuit 54.
, the brake switch 25 is turned on, and the detection circuit 52 detects that a predetermined period of time has not elapsed since the brake switch 25 was turned from ON to OFF, and the start time is determined, and the outputs of both detection circuits 51 and 52 are is inputted to the other input terminal of the AND circuit 54 via the OR circuit 53.

At the start of a full-open start, the output of the AND circuit 54 rises and the control circuit 57 of pattern A is activated, but the AND circuit 54 inverted by the inverter circuit 55
Control circuit 56 of pattern B which receives the output of circuit 54 as input
is not activated. On the other hand, when the output of the AND circuit 54 has not risen, that is, when the full-open start has not started, the control circuit 56 of pattern B, which inputs the output of the AND circuit 54 inverted by the inverter circuit 55, is activated. , the control circuit 57 of pattern A is not activated.

As explained above, in the engine intake control device according to this embodiment, when the brake is in operation or immediately after the brake has stopped operating, and the engine load is above a predetermined value, it is determined that a full throttle start is to be started. This prevents switching of the intake path length and maintains the same intake path length during stall rotation and idling, which prevents the negative pressure in the vacuum chamber 17 from being wasted. The intake path length can be reliably switched during acceleration to ensure good acceleration performance.

Further, FIGS. 5 and 6 show other embodiments of the present invention. In this embodiment, instead of detecting the start of a full-throttle start as in the above-mentioned embodiment, a state in which the engine load is above a predetermined value and the engine speed is below a predetermined value is determined to be the start time, and the intake path length is Switching length is prohibited.

That is, as shown in FIG. 5, it is determined whether the engine load is above a predetermined value by comparing the throttle opening degree TVO with a set value (step S1), and if the engine load is above a predetermined value, , it is determined whether the engine speed Ne is greater than or equal to the first set value Ne1 and less than or equal to the second set value Ne2 (step S2).

If the engine load is less than the set value, or if the engine speed Ne is less than the first set value Ne1 or exceeds the second set value Ne2, it is determined that it is not the time to start, and pattern B is applied. Control is performed (step S
3). On the other hand, when the engine load is equal to or higher than the set value and the engine speed Ne is equal to or higher than the first set value Ne1, the second set value Ne is set.
If it is 2 or less, it is determined that it is time to start, and control of pattern A is performed (step S4).

That is, to explain in terms of the hardware configuration using FIG. 6, in the comparator circuit 31, the engine speed Ne is greater than or equal to the first set value Ne1 and less than the second set value Ne2. On the other hand, the detection circuit 30 compares the throttle opening degree TVO with a set value to determine the start time.

When an H signal is output from both detection circuits 30 and 31 at the start of the start, an H signal is output from the AND circuit 32, and the control circuit 35 of pattern A is activated. On the other hand, if either of the comparison circuits 30 and 31 does not output an H signal, that is, it is not at the start time, the output of the AND circuit 32 does not rise this time, and the pattern is that the signal of the AND circuit 32 inverted by the inverter 33 is input. The control circuit 34 of B is activated.

In the engine intake control device of this embodiment as described above, switching of the intake path length is prohibited in the low engine speed region at the time of start, so that during normal operation that requires output, the intake path length is Output torque can be secured by improving filling efficiency, and during full-open acceleration, insufficient negative pressure in the vacuum chamber 17 can be prevented and the length of the intake path can be reliably switched. As a result, poor acceleration in the high output region can be reliably eliminated.

Further, FIGS. 7 to 9 show still another embodiment of the present invention, in which FIG. 9 shows the engine rotational speed Ne and shift-up timing in normal switching control,
The relationship with the opening/closing status of the control valve is shown. In this embodiment, a state in which the engine load is above a predetermined value and the rate of change in the downward direction of the engine speed is above a predetermined value is determined to be an upshift during full-throttle acceleration, and switching of the intake path length is prohibited. I try to do that.

That is, as shown in FIG. 7, it is determined from the comparison between the throttle opening degree TVO and the set value whether or not the engine load is equal to or greater than a predetermined value, that is, whether or not the engine load is at full throttle acceleration (step S10). If the load is greater than or equal to a predetermined value, the deviation ΔNe of the engine speed Ne is calculated (step S
11) It is determined whether there is an upshift based on whether the rotational speed deviation ΔNe is less than or equal to a set value (<0) (
Step S12).

[0042] If the engine load is less than the set value, or if the rotation speed deviation ΔNe is greater than or equal to the set value, that is, if the rate of change in the engine speed in the downward direction is less than the predetermined value, it is determined that the output is required. Then, normal control (pattern B) is performed (step S13). On the other hand, if the engine load is greater than the set value and the rotational speed deviation ΔNe is less than the set value,
As shown in Fig. 9, it is determined that there has been an upshift in an area where switching of the intake path length is not necessary, and control to prohibit switching (
Pattern A) is performed (step S14).

That is, to describe the hardware configuration using FIG. 8, the detection circuit 40 detects full-open acceleration by comparing the throttle opening degree TVO with a set value;
1, an upshift is detected by comparing the deviation ΔNe of the engine rotational speed with the set value. When there is a shift up at full throttle acceleration and H signals are output from both circuits 40 and 41, an H signal is output from the AND circuit 42, and pattern A
control circuit 45 is activated. On the other hand, the comparison circuits 40, 4
1 does not output an H signal, that is, when the acceleration is not at full throttle, or when there is no upshift, the output of the AND circuit 42 does not rise, and the output of the AND circuit 42 inverted by the inverter 43 does not rise. The control circuit 44 of pattern B, which receives the signal as input, is activated.

[0044] In the engine intake control device of this embodiment as described above, the upshift during full-throttle acceleration is detected and the switching of the control valves 11 and 12 is prohibited, so that unnecessary switching during upshifting is prevented. By eliminating this, it is possible to prevent waste of negative pressure, eliminate the lack of negative pressure in the vacuum chamber 17, and improve acceleration performance.

[0045]

As described above, according to the present invention, a vacuum chamber for storing intake pipe negative pressure is provided, and by introducing the negative pressure of the vacuum chamber to the actuator based on the engine speed, In an engine intake control device that switches length,
When the engine load is above a predetermined value and the engine speed is below a predetermined value, when the engine load is above a predetermined value and the rate of change in the downward direction of the engine speed is above a predetermined value, or when the shift range is automatically switched In addition to being equipped with an automatic transmission, a detection means for detecting the operation of the brakes is also provided, and when the brakes are in operation and the engine load is above a predetermined value, switching of the intake path length based on the engine speed is prohibited. As a result, unnecessary switching can be prevented and the negative pressure of the vacuum chamber with limited capacity can be effectively utilized, resulting in the effect of improving acceleration performance during full throttle acceleration.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an engine equipped with an intake control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a flow of switching control in the intake air control device.

FIG. 3 is an explanatory diagram showing the above switching control method in terms of hardware configuration.

FIG. 4 is a diagram showing a control pattern A and a normal control pattern B of the present invention in the switching control.

FIG. 5 is a diagram showing a flow of switching control of an engine intake control device according to another embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the above switching control method in terms of hardware configuration.

FIG. 7 is a diagram showing a flow of switching control of an engine intake control device according to still another embodiment of the present invention.

FIG. 8 is an explanatory diagram showing the above switching control method in terms of hardware configuration.

FIG. 9 is a diagram showing the relationship between the engine speed and upshift in normal switching control and the opening/closing status of the control valve.

[Explanation of symbols]

1 Engine 3a Surge tank 3b Surge tank 4a Intake passage 4b Intake passage 9 Communication path 10 Communication path 11 Control valve 12 Control valve 13 Actuator 14 Actuator 17 Vacuum chamber

Claims (3)

[Claims] 1. An engine comprising a vacuum chamber for storing intake pipe negative pressure, the length of the intake path being switched by introducing the vacuum chamber's negative pressure into an actuator based on the engine speed. An intake control device for an engine, characterized in that when the engine load is above a predetermined value and the engine speed is below a predetermined value, switching of the intake path length based on the engine speed is prohibited. Device. 2. An engine comprising a vacuum chamber that stores negative pressure in the intake pipe, and in which the length of the intake path is switched by introducing the negative pressure in the vacuum chamber to an actuator based on the engine speed. In the intake control device, when the engine load is above a predetermined value and the rate of change in the engine speed in a downward direction is above a predetermined value, switching of the intake path length based on the engine speed is prohibited. Characteristic engine intake control device. 3. An engine comprising a vacuum chamber for storing intake pipe negative pressure, the length of the intake path being switched by introducing the negative pressure of the vacuum chamber into an actuator based on the engine speed. The intake control device is equipped with an automatic transmission that automatically switches the gear range, and is also provided with a detection means for detecting the operation of the brake, and when the brake is in operation and the engine load is above a predetermined value, the engine rotation speed is changed. An engine intake control device characterized by prohibiting switching of intake path length based on.