JPH0723541Y2 - Intake control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an intake control device for an internal combustion engine.

[Conventional technology]

For example, in recent years, internal combustion engines mounted in passenger cars and the like have been required to satisfy the contradictory conditions of high output in addition to low pollution and fuel consumption.

Generally, in this type of internal combustion engine, improving the efficiency of intake of air into the combustion chamber is extremely important for increasing the output. For example, when trying to increase the maximum output, the equivalent intake pipe length of the engine is shortened by increasing the cross-sectional area of the intake passage, and it is given to the intake system that matches the high rotational speed range of the engine to increase the engine The intake efficiency is utilized in the rotational speed range to improve the intake efficiency.

By the way, if the cross-sectional area of the intake passage is increased in this way, the flow velocity of the air sucked in other rotational speed regions of the engine decreases, so that a large torque cannot be obtained. To address such a problem, for example, in Japanese Patent Laid-Open No. 61-255214, an intake control valve that connects two intake passages to the combustion chamber and opens and closes one of the intake passages is provided. While opening and inhaling from both intake passages, at other times, closing the control valve and inhaling from only one intake passage to match the natural frequency of the intake system to the low rotation range and utilize the intake inertia effect An intake control device capable of doing so has been proposed.

[Problems to be solved by the device]

The intake control device described above is provided with an intake control valve which is provided in the intake passage and has a variable passage cross-sectional area so as to change the equivalent intake pipe length. This control valve is operated by air pressure such as negative pressure in the intake manifold, for example. Connected to a diaphragm type actuator that controls the opening and closing of the pressure between the negative pressure chamber of this actuator and the intake manifold by the control computer so as to guide the negative pressure in the manifold to the actuator negative pressure chamber according to the engine speed. The valve is installed. By the way, when the intake control valve is to be opened, there is a constant time lag Δt from the time when the computer outputs the open signal, that is, the ON signal to the pressure switching valve until the intake control valve is fully opened. Therefore, in the conventional device, the valve opening signal is output to the pressure switching valve at the rotational speed NE _ON slightly before the target rotational speed NE _AI at which the suction efficiency is improved and the output starts to increase. However, since the number of revolutions NE _ON is set only one in the conventional device, as shown in FIG. 8, the engine rotation speed is high in the vehicle running state, for example, in the first gear (low gear) and the rotation speed increase. However, the degree of rotation increase per unit time (hereinafter referred to as "rotation increase speed") is different from that in a slower state, for example, in the case of the 4th or 5th gear (top gear). If an intake control valve that is adapted to the rotation speed increase in 4th or 5th gear is used, when accelerating in 1st gear, the target rotation speed NE _AI must be exceeded until the intake control valve closes to fully open. And the ideal starting point for intake efficiency improvement (ie NE
There was a problem that the intake control valve became a resistance until it was fully opened later than _AI ), the output momentarily decreased, and the drivability deteriorated.

[Means for Solving the Problems]

According to the present invention to solve the above problems, as shown in FIG. 1, an intake control valve for varying the equivalent intake pipe length of the engine, a drive means for driving the intake control valve, and a rotation of the engine. The engine speed sensor that detects the engine speed and the engine speed increase speed measured this time by the engine speed sensor are measured using the engine speed increase speed measured last time. And an engine speed increasing speed estimating means for estimating the engine speed increasing speed, and as the estimated future engine speed increasing speed is higher, the engine speed at the time of transmitting the valve opening signal of the intake control valve to the driving means is changed to the low speed side. The intake control valve actuation speed variable setting means to be set, and the drive means when the engine speed detected by the engine speed sensor reaches the speed set by the intake control valve actuation speed variable setting means. To An intake control device for an internal combustion engine, comprising: a valve opening / closing means for outputting the valve opening signal.

[Action]

In the intake control device for the internal combustion engine described above, the engine speed increase rate estimation means measures the engine speed increase speed measured this time by the engine speed sensor using the previously measured engine speed increase speed. The intake control valve actuation speed variable setting means estimates the engine rotation speed increase speed of the intake control valve, and drives the intake control valve opening signal as the engine rotation speed increase speed estimated accurately in this way increases. In order to variably set the engine speed when transmitting to the low speed side, no matter which gear ratio is selected in the transmission, no matter how the driver depresses the accelerator pedal, the intake control valve will fully open. The engine speed that is set can be made to match the target speed that causes inertial supercharging, and the engine output can be reliably improved.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is a sectional view showing a main part of an internal combustion engine (hereinafter referred to as an engine) in which an intake device according to the present invention is implemented, and FIG. 3 is a sectional view taken along line III-III of FIG. At 1
Shown by means the engine body. This engine body 1
Includes a cylinder 2 and a cylinder head 3, and a combustion chamber 5 is formed above the piston 4. The cylinder head 3 is formed with two intake passages 6a, 6b communicating with the combustion chamber 5, and air is introduced into the combustion chamber 5 via two intake valves 7, 7. Reference numeral 8 is an exhaust passage through which the combustion gas in the combustion chamber 5 is discharged via two exhaust valves 9,9. Reference numeral 10 is a well-known valve mechanism that drives the intake / exhaust valves 7 and 9, 11 is an electronically controlled fuel injection valve, and 12 is a spark plug.

Reference numeral 13 is a valve body connected to the cylinder head 3 corresponding to the intake passages 6a and 6b, and 14 is an intake manifold connected to the valve body 13. A surge tank 15 is provided on the upstream side of the intake manifold 14. On the upstream side of the surge tank 15, an air purifier (not shown) is provided via a manual throttle valve 16. That is, the cylinder head 3, the valve body 13, and the intake manifold 14 have two intake passages 6a and 6b, and the intake passage 17 that connects the surge tank 15 and the combustion chamber 5 to each other.
Is formed. In this intake passage 17, in order to reduce the fluid resistance of air at the time of high engine rotation, the intake passage
6a and the intake passage 6b are merged, and a large cross-sectional area is set. As for the shape of the intake passages 6a and 6b, if only one of them has a natural frequency at that time that matches the low engine speed range, an intake inertia effect can be obtained. It is set so that the intake inertia effect can be obtained by matching the range.

One of the intake passages 6a, 6b for each cylinder
Is equipped with a spiral intake control valve 18 that closes when the engine is running at low speed. In the embodiment, this control valve 18 is a valve body
It is installed in 13 and is controlled by the engine speed. That is, the arm 19 is fixed to the valve shaft 18a of the control valve 18, and the arm 19 is connected to the actuator 21 via the link 20. Actuator 21 is a case
21a, a diaphragm 21b that defines the case 21a into an atmosphere chamber 22 and a negative pressure chamber 23, a rod 21c that is connected to the diaphragm 21b and has a tip end pivotally attached to the link 20, and the rod 21c. It is composed of a spring 21d for urging the chamber 22 and the like. The negative pressure chamber 23 is connected to the negative pressure tank 25 via the pressure switching valve 24 (hereinafter, referred to as negative pressure switching valve) and the pipelines 24a and 24b. The negative pressure tank 25 communicates with the surge tank 15 of the intake manifold 14 through the pipe 25a, and the negative pressure on the engine intake side is accumulated.

26 is the actuator 21 depending on the rotation speed of the engine.
An engine control computer for controlling the engine speed sensor 29 of the distributor 28 with a signal line 27 on the input side.
It is connected to the. Further, the signal line 30 on the output side is connected to the negative pressure switching valve 24. That is, when the engine is running at a low speed, a signal for opening the negative pressure switching valve 24 and opening the negative pressure chamber 23 to the atmosphere is output from the signal line 30. On the other hand, when the engine speed increases and becomes high, the signal line 30
Outputs a signal for connecting the negative pressure switching valve 24 to the ON state and communicating the pipe line 24a with the negative pressure tank 25.

In the engine intake device configured in this way,
When the engine body 1 is operated at a low rotation speed, the engine control computer 26 turns off the negative pressure switching valve 24, and the actuator 21 opens the negative pressure chamber 23 to the atmosphere.
As a result, atmospheric pressure acts on the negative pressure chamber 23, and the control valve 18 springs.
Since it is kept closed by the urging force of 21d, air is sucked into the combustion chamber 5 only through the intake passage 6b.

Then, when the opening degree of the throttle valve 16 increases and the engine reaches a high rotation speed, this rotation is input to the computer 26 from the signal line 27, and a signal for turning on the negative pressure switching valve 24 is output from the signal line 30. It As a result, the negative pressure of the negative pressure tank 25 is introduced into the negative pressure chamber 23 of the actuator 21, and the diaphragm 21
b moves to the negative pressure side against the spring 21d. With this, the rod 21c is retracted, so that the arm 19 is rotated via the link 20 and the control valve 18 is opened, so that air is taken in by the intake passages 6a, 6a.
It is sucked into the combustion chamber 5 via b.

According to the present invention, the above-mentioned negative pressure switching valve 24 is turned off (closed).
The engine speed NE _ON when changing from the state to the on (valve opening) state is the running state of the vehicle, that is, specifically, when the rotation increases in the first gear (low gear), for example, in the second state.
Or 3rd gear, or 4th or 5th gear (top gear)
Since the rotation increasing speed is different from the case where the rotation is increasing, the setting is made differently in each case. Therefore, as shown in FIG. 4, a memory (not shown) of the engine control computer 26 stores a map of the _ON signal output rotational speed NE _ON which is preset corresponding to the rotational speed increase NE, and is detected. The higher the rotational speed increase ΔNE per unit time, the smaller the rotational speed NE _ON is set, and the control valve 18 is set to fully open with good compatibility at the target intake control valve full-open rotational speed NE _AI . .

FIG. 5 is a flow chart of a program for obtaining the degree of rotation speed increase per unit time, that is, the speed of rotation increase in the intake control device of the present invention described above. It is assumed that this program is a routine that is interrupted every predetermined unit time such as 24 ms.

First, in step S101, the current rotation speed NE _NEW is read from the engine rotation speed sensor 29. Next, in step S102, it is determined whether NE _NEW is greater than NE _OLD by comparing the number of revolutions NE _OLD read at the previous execution of this program with the number of revolutions NE _{NEW of} this time. If Yes in step S102, that is, if the engine speed has increased, the process proceeds to step S103, and the engine speed of this time
By subtracting the previous rotational speed NE _OLD from NE _{NEW and} halving it, add 1/2 of the change amount ΔNE _OLD that has been calculated up to that point to the newly calculated change amount ΔNE _NEW , The rotation speed is calculated by a so-called smoothing process. In the next step S104, the previous engine speed NE _OLD is subtracted from the current engine speed NE _NEW to obtain the change amount ΔNE _OLD to be used in the next flow execution, and in step S105, the current engine speed NE _NEW End this program with the rotation speed NE _OLD used for the next flow execution.
Incidentally, although it goes back and forth, No in step S102, that is, when the rotational speed is decreased, steps S103 and 104 are skipped and step S10
Proceed to 5 and end this program with NE _OLD ← NE _NEW . That is, the above-described program is for obtaining the amount of change ΔNE for each execution of this flow when the rotation speed is increased, and is for adjusting the intake control valve opening start timing from the negative pressure switching valve OFF state to the ON state. It detects the degree of engine acceleration.

FIG. 6 shows the rotational speed increase ΔNE detected as described above.
The number of rotations that outputs the ON signal to the negative pressure switching valve 24 according to
A program for selectively determining NE _ON and energizing and de-energizing the valve 24 according to the detected rotational speed NE, which is a routine incorporated and processed in the main routine. This routine will be described below with reference to the map shown in FIG.

First, in step S1, the engine rotation speed increase ΔNE _NEW calculated by the routine of FIG. 5 is read, and it is determined whether or not it is equal to or greater than the predetermined value x of FIG. 4, and if Yes, step S2
On the other hand, if it is less than x, it is determined as No and the step
Proceeding to S4, for example, the ON signal output speed a set for increasing the speed of the fourth or fifth gear is selected. Δ in step S2
It is determined whether NE _NEW is greater than or equal to a predetermined value y. That is, this step S2 is performed at the time of acceleration in the first gear with the largest rotation speed increase ΔNE, or is smaller than that, for example, in the second or third gear.
It is for determining whether the gear is accelerating,
If y or more, Yes is determined and the process proceeds to step S3 to select a predetermined rotation speed c smaller than the rotation speed a. Also, x ≦ ΔNE
_{If NEW} <y, the determination is No and the process proceeds to step S5 to select a predetermined value b between the rotational speeds a and c. If each ON signal output speed NE _ON (a or b or c) is selected as described above, the process proceeds to step S6, where the current engine speed NE _NEW is read from the engine speed sensor 29, NE _NEW
In each case, it is determined whether or not the predetermined number of revolutions NE _{ON selected} , that is, a or b or c or more. Then, if Yes in step S6, whether the ON signal for opening the negative pressure switching valve 24 is currently transmitted, that is, the flag F _ON =
Whether or not it is 1 is checked in step S7. If F _ON ≠ 1, a signal for turning on the negative pressure switching valve 24 is output from the output boat (not shown) of the control computer 26 in step S8. Then, in step S9, the flag F _ON is set, and this routine ends. On the other hand, Yes in step S7, that is, if the ON signal has already been output, that state is maintained and the present routine ends. Although it moves back and forth, No in the previous step S6, that is, the current rotational speed NE _NEW is the rotational speed NE _ON (a or b or c)
If it is less than the value, the process proceeds to step S10 to see if the ON signal is being output, that is, whether the flag F _ON is currently set (F _ON ← 1). If Yes, the negative pressure is switched in step S11. The valve 24 is turned off (ON signal output is stopped), the process proceeds to step S12, the flag F _ON is reset (F _ON ← 0), and this routine ends. On the other hand, if it is No in step S10, that is, if the ON signal output stop to the negative pressure switching valve 24 has already been achieved, this state is maintained and this routine is terminated and returned. Although the present embodiment has been described above with reference to the map shown in FIG. 4, the ON signal output rotation speed may be provided in correspondence with the speed increasing state of each gear.

As described above, according to the present embodiment, a map search is performed for the energized engine speed NE _ON of the negative pressure switching valve 24, which starts the valve opening operation after the intake control valve 18 is closed, according to the engine speed increasing speed ΔNE _NEW. By selecting the
As shown in the figure, the intake control valve 18 can be fully opened in a timely manner at the target rotational speed NE _AI , which is required to improve the intake efficiency corresponding to each acceleration state of the vehicle, and thus drivability is not deteriorated. . Of course, the preset rotational speeds a, b, and c are preset in consideration of the time lag Δt at which the intake control valve actually opens when the negative pressure switching valve is turned on. It can be experimentally determined by the actual acceleration state. In this embodiment, the vehicle acceleration state is divided into three gears and modeled, and the predetermined values a, b, and c are set for each of them, but in another embodiment, for example, the map of FIG. 4 is further subdivided. The rotational speed NE _ON selected in various acceleration states may be linearly changed.

〔effect〕

As described above, according to the present invention, the timing of energizing the pressure switching valve is variably set according to the rotational speed at that time so that the intake control valve can be operated at almost the same engine speed over each speed increasing state. It is possible to fully open the intake control valve.Therefore, there is no difference in the intake control valve full-open timing that has been seen in the past, and the intake passage cross-sectional area increases at an appropriate timing when the engine reaches the high-speed region where improved intake efficiency is required. This is achieved, and since the equivalent intake pipe length is reduced, the natural frequency of the intake system is increased, the output is smoothly increased, and drivability is improved.

[Brief description of drawings]

1 is a sectional view showing the claims of the present invention; FIG. 2 is a sectional view showing an essential part of an engine in which an intake control device according to the present invention is implemented; FIG. 3 is a sectional view taken along line III-III in FIG. 2; FIG. 4 is a map diagram showing the negative pressure switching valve ON signal output rotation speed NE _ON set for the rotation speed increase speed ΔNE; FIG. 5 is a flow chart diagram of a program for obtaining the rotation increase degree per unit time; Fig. 7 is a flow chart of a program for controlling intake based on the map shown in Fig. 4; Fig. 7 is a diagram showing intake control valve full opening timing in each acceleration state of the intake control device according to the present invention; The figure which shows a control valve full opening timing. 17 ... Intake passage, 24 ... Pressure switching valve, 26 ... Control computer.

Claims (1)

[Scope of utility model registration request] 1. An intake control valve for varying an equivalent intake pipe length of an engine, a drive means for driving the intake control valve, an engine speed sensor for detecting an engine speed, and an engine speed sensor. The engine speed increase rate estimation means for estimating the engine speed increase rate in the future by measuring the engine speed increase rate measured this time by using the previously measured engine speed increase rate, and the estimated future The higher the engine speed increase speed, the intake control valve operating speed variable setting means for variably setting the engine speed at the time of transmitting the valve opening signal of the intake control valve to the driving means, and the engine. Valve opening / closing means for outputting the valve opening signal to the driving means when the engine speed detected by the rotation speed sensor reaches the rotation speed set by the intake control valve operating rotation speed variable setting means. Octopus Intake air control system for an internal combustion engine characterized by.