JPH02199222A - Controller of variable length air intake pipe - Google Patents

Abstract

PURPOSE:To make it possible to utilize an inertia effect to the maximum extent all over a drive range by controlling air intake pipe length so that the pressure in an air intake pipe becomes maximum when an air intake cam opens or shuts in accordance with the range of the number of revolution of an engine. CONSTITUTION:Outlet signals from an air intake pipe pressure sensor 22 provided in the vicinity of an air intake valve 9 in a corresponding air cylinder are sampled with the signal of a cam open angle of the corresponding air cylinder obtained from a crank angle detection sensor 25 and a cam angle detection sensor 28 as a trigger in a controller 30. And air intake pipe length is changed by driving a stepping motor 19 so that the pressure in the air intake pipe becomes maximum at the shutting angle of the air intake valve 9 in the range of low speed rotation and at the opening angle in the range of high speed rotation. Consequently, the pressure in the air intake pipe becomes high at the time when the air intake cam opens, and accordingly, a large amount of new air flows in so as to make it possible to widely improve the volumetric efficiency, when the cam opens.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is capable of controlling the length of the intake pipe so that the intake pipe pressure is maximized depending on the entire operating state from low speed rotation to high speed rotation of the engine. The present invention relates to a control device for a variable length intake pipe that can maintain maximum volumetric efficiency over a range and improve output.

[Conventional technology]

Generally, in order to improve engine output, it is desirable to increase the length of the intake pipe in the engine's low-speed rotation range, and to shorten the intake pipe length in the medium-high speed range.

Therefore, as shown in Japanese Patent Application Laid-open No. 60-19914 and Japanese Patent Application Laid-open No. 60-132023, prior art has been known in which the intake pipe length is varied by detecting the engine rotation speed using a rotation speed sensor. ing.

[Problem to be solved by the invention]

However, in order to improve the volumetric efficiency of the engine, the dynamic effects in the intake pipe, that is, the inertial effects, must be optimally controlled according to a wide range of engine operating conditions. In both cases, the length of the intake pipe is set to a predetermined value based on the operating conditions, so the length of the intake pipe is uniquely controlled based on the engine speed. There are problems in that the pipe length cannot be finely adjusted, the intake pipe length is not always optimal, and the intake pipe length is unstable, and responsiveness is poor.

The present invention was proposed to address the above-mentioned problems, and is a variable-length intake pipe device for an automobile engine. After calculation processing is performed by the device, the intake pipe length is controlled by the control device so that the intake pipe pressure is maximized when the intake cam closes in the low-speed rotation range and when the intake cam opens at the high-speed rotation range. The object of the present invention is to provide a control device for a variable length intake pipe that can improve output by maximally utilizing inertia effects over the entire operating range and obtaining high volumetric efficiency.

[Means to solve the problem]

In order to achieve this object, the present invention extends the upstream side of an intake pipe that communicates with the upstream side of the intake port of the engine into an air chamber, and also arranges a variable length intake pipe in the intake pipe in the air chamber. In the variable length intake pipe device that controls the intake pipe length through a driving means, an engine speed range determination means for comparing the engine speed with a set value to determine whether the engine speed is in a low speed speed range or a high engine speed speed range; According to the output signal of the engine speed range determination means, the intake cam closing angle is detected when the engine is in a low speed range, and the intake cam opening angle is detected when the engine is in a high speed range. In response to the trigger signal from the intake cam closing angle/opening angle detection means that outputs a trigger signal in synchronization and the intake cam closing angle/opening angle detection means,
an intake pipe pressure calculation means that samples the intake pipe pressure near the intake valve and calculates the intake pipe pressure at the time of the intake cam closing angle or the intake cam opening angle; and the intake pipe pressure calculated by the intake pipe pressure calculation means. and an intake pipe pressure update/comparison means that compares the value with the value stored in the storage means to set the optimum intake pipe length and updates the stored value, and when the engine is in a low speed rotation range, when the intake cam closes the angle, The present invention is characterized in that the intake pipe length is controlled so that the intake pipe pressure is maximized at each intake cam opening angle when the engine is in a high speed rotation range.

[For production]

In such a configuration, when the engine is running, the intake port!・
The intake pipe length is set by the control device based on various signals such as the intake pipe pressure near the intake valve in the engine, the cam opening timing of the intake cam, and the engine speed at that time. The intake pipe length is controlled to the optimum length so that the intake pipe pressure is maximized at the opening angle of the intake cam in the high-speed rotation range and at the opening angle of the intake cam.

Therefore, in the entire operating range of the engine, the intake pipe pressure is at its maximum when the optimum intake pipe length is set, so a large amount of fresh air is introduced into the combustion chamber the moment the intake cam opens, resulting in high volumetric efficiency. Obtainable.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a control device for a variable length intake pipe according to the present invention. In the figure, symbol ■ indicates cylinder block 2. The engine body consists of a cylinder head 3, and each cylinder 2a of the cylinder block 2 is provided with a piston 5 that slides up and down via a connecting rod 4 by a crankshaft (not shown).

Further, an intake port 7 and an exhaust port 8 are communicated with the combustion chamber 6 of the cylinder head 3, and an intake valve 9 that opens at a predetermined timing is connected to the opening of the intake port 7 and the exhaust port 8, respectively. An exhaust valve 10 is installed.

A throttle valve 29 is provided on the upstream side of the intake port 7.
One end of the intake pipe 11 is connected to the throttle body 11a through the throttle body 11a, and the other end of the intake pipe 11 has a curved portion ttb curved into an arc having a radius R1.
is formed, and this curved portion ttb extends into the air chamber 13 of the variable intake device 12.

The air chamber 13 has a volume expanded in the cylinder row direction in the case of a multi-cylinder engine, and air sucked from the air cleaner 14 is introduced through an intake pipe 15. At the center of the curvature of the curved intake pipe 11 in the air chamber 13, as shown in FIG.
It is rotatably supported via bearings 17 provided on side walls 13a and 13a of 3.

The drive shaft 16 also has an air duct (
A variable length intake pipe) 18 is installed via the stem part lea, and the base end 18a of the air duct 18 is movably arranged inward from the open end 11d of the curved part ttb of the intake pipe 11. ing. Here, a stepping motor I9 that rotates forward and backward in response to a signal from a control device 35, which will be described later, is installed at one end of the drive shaft 1B, and the rotation of the drive shaft 1B causes the base end of the air duct 18 to 18
a is the curved portion 11.a of the intake pipe 11. The intake pipe length Ln of the air duct 18 that is moved inside the intake pipe 11 and extends from the open end lid of the curved portion 111J of the intake pipe 11 can be made variable.

In addition, the tip 111b of the air duct ift is formed into a bell mouth shape and opens into the air chamber 13, so that even when the intake pipe length 11n is the longest (J, 1ax),
Curved portion 11 of intake pipe 11. A stopper (not shown) is provided to prevent it from coming off the opening end lid of b.

Further, at a predetermined position on the side wall 13a in the air chamber 13, an intake pipe length longest detection sensor 20 consisting of an electromagnetic pickup or the like is installed. When the position is detected, it is detected that the intake pipe length ftn of the air duct 18 is the longest (JIll1ax), and this signal is output to the control device 35.

On the other hand, in order to detect the intake pipe pressure of the intake air introduced into the combustion chamber 6 from the intake port 7 of the engine I, an intake pipe pressure sensor detects the intake pipe pressure near the intake valve 9 of the intake port 7 of each cylinder. 22 are installed corresponding to each cylinder, and an output signal from this intake pipe pressure sensor 22 is output to a control device 35.

Further, a crank angle detection sensor 25 for detecting a crank angle is installed opposite to a crank rotor 24 provided on a crankshaft 23 of the engine 1, and a cam rotor 27 fixed to a camshaft 26 is provided with a crank angle detection sensor 25 for detecting a crank angle. A cam angle sensor 28 is installed for cylinder discrimination. Further, the throttle valve 29 installed in the throttle body Lla is provided with a throttle position sensor 30 that detects the throttle opening, and an idle switch 3I that detects the idling position where the throttle valve 29 is fully closed. The intake pipe length longest detection sensor 20. Intake pipe pressure sensor 22. Crank angle detection sensor 25. Cam angle sensor 28. Throttle position sensor 30. The output signals from the idle switch 31 and the idle switch 31 are respectively input to the control device 35.

The control device 35 includes the intake pipe pressure sensor 22. Crank angle detection sensor 25. Cam angle sensor 28. Intake pipe length longest detection sensor 20. Throttle position sensor 30, idle switch 31. and ignition switch 3
It receives the output signal from 6, performs arithmetic processing, and outputs a driving signal for forward or reverse rotation to the stepping motor 19.

Here, the control device 35 has an input/output interface I10 port 35. a, I/O port 35
It consists of a CPU 35b that processes signals from a, a ROM 35c that stores control programs, etc., a RAM 356 that temporarily stores data, etc., and performs arithmetic processing for driving the stepping motor 19 according to a predetermined program. The drive signal is outputted from the drive circuit 35e to rotate the stepping motor 19 forward or reverse.

On the other hand, if the engine l is a four-cylinder engine, the third
As shown in the figure, the crank rotor 24 has #1. #2 cylinder intake cam opening angle detection protrusion (slits may also be used) 24
a and #3. #4 cylinder intake cam opening angle detection protrusion 24b
And #1. #2 cylinder intake cam closing angle detection protrusion 24c; #3. #4 cylinder intake cam closing angle detection protrusion 24d is provided, and the cam rotor 27 is provided with a #4 cylinder intake cam closing angle detection protrusion 24d.
1. #3゜#2. Cylinder discrimination protrusion (slit may also be used) 27a (1 piece) for discriminating each cylinder according to #4,
27b (3 pieces), 27c (2 pieces), 27d (
4 pieces) are provided for the tail.

Further, the protrusions 24a to 24 of the crank rotor z4
The crank pulse signal from the crank angle detection sensor 25 that detects d and the cam pulse signal from the cam angle sensor 28 that detects the protrusions 27a to 27d of the cam rotor 27 are set as shown in the timing chart of FIG. , the number of cam pulses in the cam pulse group represents the corresponding cylinder number, and the crank pulse input next to the cam < Lus group is the intake cam opening angle ),
The next input crank pulse is set to represent the intake cam closing angle χ2 (intake valve 9 open→closed) in the previous cylinder in the ignition order of the cylinder represented by the number of cam pulses.

FIG. 5 shows the relationship between the fluctuation of the intake pipe pressure in the intake port 7 and the intake cam angle. Using the signal synchronized with the intake cam opening angle χ1 of the corresponding cylinder as a trigger, the output signal from the intake pipe pressure sensor 22 that detects the intake pipe pressure in the intake port 7 near the intake valve 9 in the corresponding cylinder is sampled. Calculate the intake pipe pressure at the intake cam opening angle χ1, average the intake pipe pressure at the intake cam opening angle χ1 in each cylinder, and step the pressure so that the intake pipe pressure P1 at this time becomes the maximum. Drive the motor 19 to determine the intake pipe length j! In addition, in the case of an engine medium speed rotation range, the intake cam is controlled by sampling the output signal from the intake pipe pressure sensor 22 in the corresponding cylinder using a signal synchronized with the intake cam closing angle χ2 of the corresponding cylinder as a trigger. The intake pipe pressure at the closing angle χ2 is calculated, the intake pipe pressure at the intake cam closing angle χ2 in each cylinder is averaged, and the stepping motor 19 is activated so that the intake pipe pressure P2 at this time becomes the maximum. It is driven to control the intake pipe length Jtn.

Furthermore, the functional configuration of the control device 35 is as shown in the block diagram of FIG. Longest intake pipe length determining means 51. Idle determination means 52. Engine rotation speed calculation means 53. Engine speed range determination means 54, throttle opening change rate calculation means 55. Acceleration determining means 5B, cylinder determining means 57. Intake cam closing angle/opening angle detection means 5B, intake pipe pressure calculation means 59. Memory means 60, intake pipe pressure update/
Comparison means 61. and stepping motor drive means 62
Consisting of

Hereinafter, the functions of the control device 35 configured as described above will be described as the sixth function.
The explanation will be based on the block diagram shown in the figure.

First, the start determination means 50 detects the ignition switch 3
When the control device 35 is turned on by the signal from B, it is determined that the start has started, and a normal rotation drive signal is output to the stepping motor 19 via the stepping motor drive means 63 to rotate the stepping motor 19 in the normal direction, thereby causing the drive shaft 1B to rotate. The air duct 18 is rotated clockwise in FIG. 1 through the air duct 18, and is driven in the longest direction of the intake pipe length. Note that the start determining means 50 drives the stepping motor 19 only at the time of starting, and thereafter the start determining means 50 stops driving the stepping motor 19 and outputs a determination command signal to the idle determining means 52.

When the protrusion 21 of the drive shaft 1B faces the longest intake pipe length detection sensor 20, the longest intake pipe length determining means 51 receives an output from the longest intake pipe length detection sensor 20, and determines that the intake pipe length is the longest and starts the stepping motor. Drive means 62
A normal rotation direction drive stop signal is output to the stepping motor 19 to stop driving the stepping motor 19.

When a determination command signal is input from the start determination means 50 after the engine is started, the idle determination means 52 turns the idle switch 31 (turned ON when the throttle valve is fully open) to O.
When the idle switch 31 is ON, that is, when idling, a normal rotation drive signal is applied to the stepping motor 19 via the stepping motor drive means B2 to drive the stepping motor 19 in the longest direction of the intake pipe length. On the other hand, when the idle switch 31 is OFF, a determination command signal is given to the engine rotation speed range determining means 54.

The engine rotation speed calculation means 53 calculates the engine rotation speed N based on the crank pulse signal from the crank angle detection sensor 25.

The engine rotation speed range determining means 54 includes the idle determining means 5
When the determination command signal when the idle switch 31 is OFF is given from 2, the engine rotation speed calculation means 53
Read the engine rotation speed N calculated in , compare the engine rotation speed N with a set value No (for example, 3000 rpm), and if N<NQ, determine that the engine is in the low speed rotation range,
A computation command signal is given to the throttle opening change rate calculation means 55, and on the other hand, when N≧No, it is determined that the engine is in the high speed rotation range, and the intake cam closing angle/opening angle detection means 58 is notified of the engine high speed rotation. give a signal.

The throttle opening change rate calculating means 55 reads the output signal from the throttle position sensor 30 when the calculation command signal for the low engine speed rotation range is input from the engine speed range determining means 54, and calculates the throttle opening change rate per unit time. Opening change amount, that is, throttle opening change rate dθ/d
t is calculated and a signal is output to the acceleration determining means 56.

The acceleration determination means 56 is the throttle opening change rate calculation means 5.
The throttle opening change rate dθ/dt calculated in step 5 is read, the throttle opening change rate dθ/dt is compared with the reference setting value A, and if dθ/d t >A, it is determined that the operation is accelerating. The low-speed rotation/acceleration signal is output to the intake cam closing angle/opening angle detection means 58, and when dθ/dt≦A, it is determined that the operating state is low-speed rotation/steady operation, and the low-speed rotation/steady signal is output to the intake cam closing angle/opening angle detection means 58. It is output to the opening angle detection means 58.

The cylinder discrimination means 57 reads the crank pulse signal from the crank angle detection sensor 25 and the cam pulse signal from the cam angle sensor 28, discriminates the cylinder, and outputs the discriminated cylinder signal to the intake cam closing angle/opening angle detection means 58. do.

Here, the crank pulse from the crank angle detection sensor 25 and the cam pulse from the cam angle sensor 28 are set as shown in the timing chart of FIG. 4, and the number of cam pulses in the cam pulse group represents the corresponding cylinder number.
The first crank pulse input next to the cam pulse group represents the intake cam opening angle χ1 of the corresponding cylinder expressed by the above cam pulse number, and the second crank pulse is expressed by the above cam pulse number. It is set to represent the intake cam closing angle χ2 of the previous cylinder in the cylinder ignition order.

Therefore, the cylinder determining means 57 determines the corresponding cylinder by counting the number of cam pulses in a group of cam pulses input after a crank pulse is input until the next crank pulse is input.

The intake cam closing angle/opening angle detecting means 58 is connected to the engine rotation speed range determining means 54. The signal from the acceleration determining means 56 is read, and when the engine high speed rotation signal is input, the crank pulse (intake cam opening angle χ
1), the trigger signal of the corresponding cylinder discriminated by the cylinder discriminating means 57 is transmitted to the intake pipe pressure calculating means 59.
Output to. Furthermore, when a low-speed rotation/acceleration or low-speed rotation/steady signal is input, the cylinder discriminating means 57 performs a signal in synchronization with the second crank pulse (corresponding to the intake cam closing angle χ2) after the cam pulse is input. A trigger signal for the cylinder immediately preceding the determined cylinder in the ignition order is output to the intake pipe pressure calculation means 59. Furthermore, when an engine medium speed rotation signal is input, a trigger signal for the corresponding cylinder determined by the cylinder determination means 57 is synchronized with a crank pulse (corresponding to the intake cam opening angle χ1) input next to the cam pulse. , and in synchronization with the second crank pulse (corresponding to the intake cam closing angle χ2) after the input of the cam pulse, the trigger signal for the previous cylinder in the firing order of the cylinder determined by the cylinder determining means 57 is transmitted. Intake pipe pressure calculation means 5
Output to 9.

The intake pipe pressure calculation means 59 reads the output signal from the intake pipe pressure sensor 22 in the corresponding cylinder in synchronization with the trigger signal from the intake cam closing angle/opening angle detection means 58, and reads the output signal from the intake pipe pressure sensor 22 in the corresponding cylinder for one cycle (when the crankshaft is intake cam opening angle χ1 for each cylinder (when rotating). Alternatively, by averaging the intake pipe pressure at the intake cam closing angle χ2,
The intake pipe pressure Pi when the intake cam opening angle is χ1 or the intake pipe pressure P2 when the intake cam closing angle is χ2 is calculated.

The intake pipe pressure updating/comparing means 61 includes the engine speed range determining means 54. The signal from the acceleration determining means 56 is read, and when the engine high speed rotation signal is input, the intake pipe pressure P1 at the intake cam opening angle χ1 calculated by the intake pipe pressure calculating means 59 is read, and this is used as the previous value. is stored in the storage means 60 as intake pipe pressure data P10LD, and thereafter, a reverse drive signal for one step is given to the stepping motor 19 via the stepping motor drive means 62, and the stepping motor 19 is rotated in the counterclockwise direction in FIG. , the intake pipe length 1n is shortened by 1 pitch, and then the intake pipe pressure P1 at the time of the intake cam opening angle χ1 is newly read from the intake pipe pressure calculation means 59, and the intake pipe length Jln is shortened by 1 pitch. The above intake pipe pressure P10LD and intake pipe length 1
Compare the intake pipe pressure P1 after reducing n by one pitch,
Intake pipe length j until P1to≦P1! n is shortened by 1 pitch, and when l'1oLo≦P1, the intake pipe length 1n is lengthened by 2 pitches, and then the output signal from the engine speed range determining means 54° acceleration determining means 56 is newly output. Load.

On the other hand, when the low speed rotation/acceleration signal is manually input from the acceleration determining means 56, the intake pipe pressure updating/comparing means 61 calculates the intake cam closing angle χ calculated by the intake pipe pressure calculating means 59.
2, and stores this in the storage means 61 as the previous intake pipe pressure data P20LD;
Thereafter, a reverse drive signal for one step is given to the stepping motor 19 via the stepping motor drive means 62, the intake pipe length 1n is shortened by one pitch, and then the intake cam closing angle χ2 is newly calculated from the intake pipe pressure calculation means 59. Read the intake pipe pressure P2 at the time of and compare the intake pipe pressure data P20LD before shortening the intake pipe length Jln by 1 pitch with the intake pipe pressure P2 after shortening the intake pipe length 1n by 1 pitch, and determine that P20LD≦P2. The intake pipe length 1n is shortened by 1 pitch until P20LD≦P2, the intake pipe length 1n is lengthened by 2 pitches, and then the engine speed range determining means 54. The output signal from the acceleration determining means 56 is read.

Further, when the engine low speed rotation/steady signal is input from the acceleration determining means 56, the intake pipe pressure updating/comparing means 61
reads the intake pipe pressure P2 at the intake cam closing angle χ2 calculated by the intake pipe pressure calculation means 59, stores this in the storage means 61 as the previous intake pipe pressure data P20LD, and then drives the stepping motor. A forward rotation drive signal for one step is applied to the stepping motor 19 via the means 62, the stepping motor 19 is rotated clockwise in FIG. 1, the intake pipe length 1n is lengthened by one pitch, and then a new intake pipe is The intake pipe pressure P2 at the intake cam closing angle χ2 is read from the pressure calculation means 59, and the above intake pipe pressure data P20LD is obtained before the intake pipe length 1n is lengthened by one pitch.
and the intake pipe pressure P2 at the intake cam closing angle χ2 after increasing the intake pipe length Ln by one pitch, and P20LD≦
Shorten the intake pipe length Jln by 1 pitch until it reaches P2,
If it becomes P2ot, o5P2, change the intake pipe length An to 2.
The pitch is shortened, and then a new engine speed range determination means 54. The output signal from the acceleration determining means 56 is read.

Next, the control procedure by the control device 35 will be explained according to the flowchart shown in FIG.

The control device 35 receives a signal from the ignition switch 36.
When turned on, first, in step 81, a normal rotation drive signal is given to the stepping motor 19, and the stepping motor 1
9 is rotated in the clockwise direction in FIG. 1 via the drive shaft I6, and when the protrusion 21 of the drive shaft 16 faces the longest intake pipe length detection sensor 20,
The intake pipe length 1n is determined to be the longest and the stepping motor 19
By stopping the driving of the stepping motor 19, the stepping motor 19 is stopped at the position where the intake pipe length is the longest, thereby making the intake pipe length 1n the longest when starting the engine.

Next, the process proceeds to step S2, where it is determined whether or not the idle switch 31 is on. If the idle switch 32 is on, the process returns to step S1, and the intake pipe length 1n is made the longest. Further, if the idle switch 31 is OFF, step S
3, the engine rotation speed N is calculated based on the output signal of the crank angle detection sensor 25.

Next, in step S4, the engine speed N and set value No.
(for example, 3000 rpm), and if N<NQ, it is determined that the engine is in the low speed rotation range and the process proceeds to step S5; if N≧No, it is determined that the engine is in the high speed rotation area and the process proceeds to step S319.

In step S5, the output signal of the throttle position sensor 30 is read, and the throttle opening change amount per unit time, that is, the throttle opening change rate dθ/dt is calculated, and the process proceeds to step S6, where the throttle opening change rate dθ/dt is calculated.
t is compared with the reference setting value A, and if dθ/d t >A, it is determined that the operation is accelerated and the process proceeds to step 813, where dθ
If /dt≦A, it is determined that the operating state is steady and the process proceeds to step S7.

When the process proceeds to step S7, the process proceeds to step 5200 shown in FIG. 8 due to an interruption.

Steps 5200 to 5211 are a flowchart for sampling the intake pipe pressure P2 when the intake cam closing angle is Cy is counted up by +1 and the process proceeds to step 5201. After the cam pulse signal is input, it is determined whether or not the crank pulse signal from the crank angle detection sensor 25 is input. If the crank pulse signal is not manually input, step 5201 is performed. Return to
Furthermore, when one cam pulse is input, the cam pulse counter cy is counted up by +1, and after the cam pulse is input, when a crank pulse from the crank angle detection sensor 25 is manually input, the process advances to step 5202 and cylinder discrimination is performed. That is, the crank pulse from the crank angle detection sensor 25 that detects the protrusions 24a to 24d of the crank rotor 24, and the protrusions 27a to 27d of the cam rotor 27.
The cam pulse from the cam angle sensor 28 that detected the fourth
Since the settings are as shown in the timing chart in the figure, step 3200. After a cam pulse is manually input in step 5201, the corresponding cylinder can be determined by counting the number of cam pulses in a group of manually input cam pulses until the next crank pulse is input manually. If three cam pulses are manually input before the crank pulse of #
3 cylinders), in this case, the intake cam closing angle χ2
In order to detect the timing of , in step 5202, the previous cylinder is determined based on the ignition order of the cylinder represented by the number of cam pulses. For example, if the engine has 4 cylinders and the ignition order is #1 → #3 → #2 → #4 cylinder, this is stored in advance as data in the ROM 35c of the control device 35, and the number of cam pulses in the cam pulse group is If the cylinder determined by is the #3 cylinder, the previous cylinder in the ignition order is determined to be the #1 cylinder. Then, in step 8203, when one crank pulse is input after the cam pulse is input, the crank pulse counter Cr is counted up by +1, and in step 5204, the count value of the crank pulse counter Cr is greater than or equal to nr (for example, 2 or more). is determined, and if Cr<nr, return to step 5203;
Furthermore, when the next crank pulse is input, the crank pulse counter Cr is counted up by +1. If it is determined in step 5204 that Cr≧nr, the process advances to step 5205. That is, when nr (2) crank pulses are input after the cam pulses in the cam pulse group are manually input, this is when the cylinder (#1 cylinder) determined in step 5202 reaches the intake cam closing angle χ2. , this is determined in step 8204, and step 52
At step 05, in synchronization with this, the output signal of the intake pipe pressure sensor 22 (#1 intake pipe pressure sensor) of the cylinder (#1 cylinder) discriminated at step 8202 is read, and the intake pipe pressure P2 is read.
Calculate. As a result, the intake pipe pressure P2 when the corresponding cylinder has the intake cam closing angle χ2 is calculated.

Next, the process proceeds to step 820B, where the cam pulse counter Cy is cleared (Cy←φ), and in step 8207, the crank pulse counter C is cleared (Cr←φ).

Next, the process advances to step 8208, where the 1-cycle determination counter C1 is counted up by 1, and the process proceeds to step 5209, where the value of the 1-cycle determination counter C1 becomes rz (
For example, in the case of a 4-cylinder engine, it is determined whether CI is greater than or equal to rz -4), and if CI<nl, the process returns to step 5200 and steps 8200 to 3208 are repeated.

As a result, one cycle (the crankshaft 23
intake cam closing angle χ for each cylinder (when rotating 20')
The intake pipe pressure P2 at step 2 is calculated.

Also, if C1≧01, step! Proceed to 3210,
Intake pipe pressure P at intake cam closing angle χ2 in each cylinder
2 is averaged, and this average value v2 is calculated as the intake cam closing angle χ
Set it as the intake pipe pressure P2 at step 321.
1 clears the counter C1 for determining one cycle (C1←φ
), the sampling of the intake pipe pressure P2 is completed, and the process proceeds to step s8 in FIG.

In step S8, the intake pipe pressure P2 at the intake cam closing angle χ2 sampled as described above is stored and updated in the RAM 35d as the previous intake pipe pressure data P20LD, and the process advances to step S9 to update the stepping motor 19.
Drive one step forward rotation to obtain the intake pipe length j! Increase n by one pitch and proceed to step 81G.

In addition, the intake pipe length j! If n is already the longest, jump to step S9 and proceed to step sl after a predetermined time.

Proceed to.

Proceeding to step SlO, the program for sampling the intake pipe pressure P2 at the intake cam closing angle χ2 described above starts, and the intake pipe pressure P2 is newly sampled in steps 8200 to 5211, and step St
t, and this newly sampled intake pipe pressure P2
and the previous intake pipe pressure data P20LD stored in step s8, and if P2゜LD>P2, the process returns to step S7, and if P20LD≦P2, the process proceeds to step 812 where the stepping motor 19 is driven in two steps in reverse, and the intake pipe length j! Shorten n by 2 pitches and return to step S2.

In other words, when the engine is running at low speed and in a steady state, the intake cam closing angle χ2 before increasing the intake pipe length Jtn by one pitch
The intake pipe pressure P2oto and the intake pipe length j! Compare the intake pipe pressure P2 at the intake cam closing angle χ2 after increasing n by one pitch, and increase the intake pipe length by 11. Increase n by 1 pitch, P2oto:5P2
If this happens, shorten the intake pipe length 1n by 2 pitches, and then repeat this process based on the judgment to shorten the intake pipe length j.
! n is controlled so that the intake pipe pressure P2 at the intake cam closing angle χ2 is maximized.

On the other hand, if it is determined in step SB that dθ/d t >A and the acceleration state is present, the process proceeds to step 813, and samples the intake pipe pressure P2 at the intake cam closing angle χ2 in steps 5200 to 5ztt. In step S14, this is converted into the previous intake pipe pressure data P2゜L.
D, the intake pipe pressure data P20LD is stored in the RAM 35d, and the process proceeds to step S15, where the stepping motor 19 is reversely driven by one step, thereby increasing the intake pipe length to 1! Step SlB by shortening n by 1 pitch
Proceed to. In step S16, the intake pipe pressure P2 is newly sampled in steps 8200 to 5211, and the process proceeds to step 317, where the newly sampled intake pipe pressure P2 and the previous intake pipe pressure data P20LD stored in step 914 are combined. If P2oto>P2, return to step 813,
If P2°LD≦P2, the program proceeds to step S18, where the stepping motor 19 is driven in forward rotation by two steps, the intake pipe length 1n is lengthened by two pitches, and the process returns to step S2.

Therefore, when operating the engine at low speed and acceleration, the intake pipe length j! Intake cam closing angle χ before n is shortened by 1 pitch
Intake pipe pressure P20LD and intake pipe length j! n to 1
Compare the intake pipe pressure P2 at the intake cam closing angle χ2 after shortening the pitch, and increase the intake pipe length j! until P20LD≦P2! Shorten n by 1 pitch < C, P 20LD≦P2
If this happens, the intake pipe length ln is lengthened by 2 pitches, and this process is repeated based on the determination, so that the intake pipe length 1n is controlled so that the intake pipe pressure P2 at the time of the intake cam closing angle χ2 is maximized. Ru.

Further, if it is determined in step S4 that N≧No and the engine is rotating at high speed, the process advances to step S19.

When the process proceeds to step S19, the process proceeds to step 5100 shown in FIG. 9 due to an interruption. step sio.

Steps 8108 to 8108 are a flowchart for sampling the intake pipe pressure P1 when the intake cam opening angle χ1, and in step 5too, the cam pulse signal from the cam angle sensor 28 is read, and when one cam pulse is input, the cam pulse counter Cy is counted by +1. Step 81
After the cam pulse signal is input manually, it is determined whether the crank pulse signal from the crank angle sensor 25 is input, and if the crank pulse signal is not input, the process proceeds to step STO.

Returning to step 5102, when one more cam pulse is input, the cam pulse counter Cy is counted up by +1, and after another cam pulse is input, when the crank pulse from the crank angle sensor 25 is manually input, the process advances to step 5102, and the cam pulse counter Cy is counted up by +1. Cylinder discrimination is performed based on the count number of Cy.

That is, as shown in the timing chart of FIG.
Step 8100゜ After the crank pulse is manually input in step 5101, the corresponding cylinder is determined in step 5102 by counting the number of cam pulses in the cam pulse group input until the next crank pulse is input. . Then, after the cam pulses in the cam pulse group have been input, the time when the crank pulse for one outlet is manually input is when the intake cam opening angle χ1 is reached, and in synchronization with this, in step St port 3, step 510
The output signal of the intake pipe pressure sensor 22 of the cylinder determined in is read, and the intake pipe pressure P1 is calculated. by this,
The intake pipe pressure P1 when the corresponding cylinder has the intake cam opening angle χ1 is calculated.

Next, the process proceeds to step 8104, where the cam pulse counter Cy is cleared (Cy←φ), the process proceeds to step 3105, where the 1-cycle discrimination counter C1 is counted up by +1, and the process proceeds to step 8106, where the value of the 1-cycle discrimination counter C1 is is nl (for example, in the case of a 4-cylinder engine, nl
l = 4) or more, and (if 1<nl, return to step 8100 and perform steps 5too to 510 above).
Repeat step 5. As a result, the intake pipe pressure P1 at the intake cam opening angle χ1 in each cylinder in one cycle (when the crankshaft 23 rotates 720'') is calculated.Furthermore, if C1≧01, the process advances to step 5107. , intake pipe pressure P1 at intake cam opening angle χ1 in each cylinder
is averaged, and this average value v1 is calculated as the intake cam opening angle χ1
Set as the intake pipe pressure P1 at step 810g.
Clear the 1 cycle discrimination counter C1 with (Ct-φ)
Then, sampling of the intake pipe pressure P1 is completed, and the process proceeds to step 820.

In step 320, the intake pipe pressure P1 at the intake cam opening angle χ1 sampled as described above is stored and updated in the RAM 35d as the previous intake pipe pressure data P10LD, and the process proceeds to step S21, where the stepping motor 19 is The intake pipe length in is shortened by one pitch by driving in reverse step.

Next, when the process proceeds to step 822, the intake pipe pressure P1 at the intake cam opening angle χ1 is newly sampled in steps 5100 to 510g, and the process proceeds to step 823, where the newly sampled intake pipe pressure P1 and
The previous intake pipe pressure data P10LD stored in the above step 32G is compared with P1. If LD>Pl, the process returns to step S19; if P10LD≦P1, the process proceeds to step S24, where the stepping motor 19 is driven in forward rotation by two steps to lengthen the intake pipe length An by two pitches, and the process returns to step S2. .

Therefore, when the engine rotates at high speed, the intake pipe length j!
Intake pipe pressure P10LD at intake cam opening angle χ1 before n is shortened by 1 pitch and intake pipe length, 1! Compare the intake pipe pressure P1 at the intake cam opening angle χ1 after shortening n by one pitch, and increase the intake pipe length 1n until F'1oto≦P1.
is shortened one pitch at a time, and when PloLo:5P1 is reached, the intake pipe length 11 is lengthened by two pitches, and this process is repeated based on the judgment, so that the intake pipe length j! n is
The intake pipe pressure P1 at the intake cam opening angle χ1 is controlled to be maximum.

In this embodiment, the intake pipe pressure sensor 2 detects the intake pipe pressure immediately upstream of the intake valve 9 of the intake port 7 of each cylinder.
2 are arranged corresponding to each cylinder, and the intake pipe pressure at the intake cam closing angle χ2 and the intake cam opening angle χ1 of each cylinder is determined, and this is averaged to obtain the intake pipe pressure p2. p
1, however, the intake pipe pressure sensor 22 is provided only for one cylinder, and the intake cam closing angle χ2. Alternatively, the intake pipe pressure at the opening angle χ1 is determined, and this is calculated as the intake pipe pressure P2. Alternatively, it may be set as Pl.

〔Effect of the invention〕

As explained in detail above, according to the variable length intake pipe device of the present invention, various parameters such as the intake pipe pressure near the intake valve in the intake port, the cam opening timing of the intake cam, and the intake pipe length at that point can be adjusted. The control device receives the signal and processes it, and based on the signal, the intake pipe length is controlled to the optimum length so that the intake pipe pressure is maximized when the intake cam is closed when the engine is running at low speeds, and when the intake cam is open when the engine is running at high speeds. If the intake pipe pressure is high, a large amount of fresh air will flow in when the cam opens, greatly improving volumetric efficiency.

In addition, the intake pipe length is set to the longest when the engine is started and when idling, and the intake pipe pressure is set to the maximum according to the cam opening timing of the intake cam in all operating conditions from low engine speed range to high engine speed range. By changing the length of the intake pipe to the optimum length over the entire operating range, volumetric efficiency can be improved, which can improve engine output.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a control device for a variable length intake pipe according to the present invention, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is an explanatory diagram showing the relationship between a crank rotor and a cam rotor.
FIG. 4 is a timing chart showing the relationship between cam pulses and crank pulses, FIG. 5 is an explanatory diagram showing the relationship between intake cam angle and intake pipe pressure, FIG. 6 is a block diagram showing the functions of the control device, and FIG. 9 through 9 are flowcharts illustrating the control procedure of the control device according to the present invention. l...Engine, 3...Cylinder head, 7...
Intake port, 9... Intake valve, 11... Intake pipe,
llb...Bending portion, 12...Variable intake device, 13.
... Air chamber, 1B... Drive shaft, 18... Air duct, ■9... Stepping motor, 20... Intake pipe length longest detection sensor, 22... Intake pipe pressure sensor,
25... Crank angle detection sensor, 28... Cam angle sensor, 35... Control device, 54... Engine speed range discrimination means, 58... Intake cam closing angle/opening angle detection means, 59 ...Intake pipe pressure calculation means, 61...Intake pipe pressure updating/comparison means. Patent applicant Fuji Heavy Industries Co., Ltd. Figure 2 Figure 5 Agent Patent attorney Nobu Kobashi Slag amount

Claims (1)

[Scope of Claims] The upstream side of an intake pipe that communicates with the upstream side of the intake port of the engine is extended into an air chamber, and a variable length intake pipe is arranged in the intake pipe in the air chamber, and In a variable length intake pipe device that controls the length of the intake pipe, the engine speed range determining means compares the engine speed with a set value to determine whether the engine is in a low engine speed range or a high engine speed range; According to the output signal of
An intake cam closing angle/opening angle detection means outputs a trigger signal in synchronization with the intake cam closing angle or intake cam opening angle, and a detection means near the intake valve according to the trigger signal from the intake cam closing angle/opening angle detection means. an intake pipe pressure calculation means for sampling the intake pipe pressure and calculating the intake pipe pressure at the intake cam closing angle or the intake cam opening angle; and a storage means for storing the intake pipe pressure calculated by the intake pipe pressure calculation means. It is equipped with an intake pipe pressure update/comparison means that compares it with a stored value and sets the optimum intake pipe length, and also updates the stored value.
When the engine is in the high speed range, the intake cam opening angle
A control device for a variable length intake pipe, characterized in that the intake pipe length is controlled so that each intake pipe pressure is maximized.