JPH02199220A - 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 an air intake pipe passage so that the pressure in an air intake pipe becomes maximum when an air intake cam opens. CONSTITUTION:The pressure in an air intake pipe at the time when the cam of each air cylinder opens is subjected to averaging process by detecting the pressure in an air intake pipe at the time when a cam opens by way of sampling the output signals from an air intake pipe pressure sensor 22 provided in the vicinity of an air intake valve 9 in a corresponding cylinder with the signal of a cam open angle of the corresponding cylinder obtained from a crack angle detection sensor 25 and a cam angle detection sensor 28 as a trigger, in a controller 30. Thereafter, the air intake pipe length is changed by driving a stepping motor 19 so that the pressure in the air intake pipe becomes maximum. Consequently, as the pressure in the air intake pipe becomes high at the time when the air intake cam opens, 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- and high-speed rotation 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 includes a variable length intake pipe device for an automobile engine.
After the control device performs arithmetic processing according to pressure fluctuations in the intake pipe, intake cam opening angle timing, etc., the drive device controls the intake pipe length to maximize the inertia effect over the entire operating range. The object of the present invention is to provide a control device for a variable length intake pipe that can improve output by obtaining volumetric efficiency.

[Means for Solving the Problems] 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 In an engine having a variable length intake pipe device in which a variable length intake pipe is installed in the pipe, the length of the intake pipe is variable by forward or reverse rotation of a stepping motor, an intake pipe pressure sensor installed near the intake valve of the engine; , an intake cam opening angle detection sensor that detects the intake cam opening angle, and a control device that receives signals from the longest intake pipe length detection sensor and calculates the optimum intake pipe length. The intake pipe length is controlled so that the intake pipe pressure at this time is maximized by the intake cam opening angle determined.

[For production]

In such a configuration, while the engine is running, the control device receives various signals 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, and performs calculation processing. At the same time, the drive device controls the intake pipe length to the optimum length so that the intake pipe pressure is maximized.

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, reference numeral 1 denotes an engine body consisting of a cylinder block 2 and a cylinder head 3, and each cylinder 2a of the cylinder block 2 has a piston 5 that slides up and down via a connecting rod 4 by a crankshaft (not shown). is installed.

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 lO is installed.

One end of an intake pipe 11 is communicated with the upstream side of the intake port 7 via a throttle body 11a having a throttle valve 11b, and the other end of this intake pipe 11 is connected to the
A curved portion 11c curved into an arc having a curvature of radius R1 is formed, and this curved portion 11c 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.
The side wall 13a of No. 3 is rotatably supported via a bearing 17 provided on L3a.

In addition, the drive shaft [6 has an air duct (
(variable length intake pipe) 1g is installed via the stem part lea, and the base end 18a of the air duct 18 is slidably disposed inside from the open end of the curved part lie of the intake pipe 11. ing. Here 1. A stepping motor 19 that rotates forward and backward in response to a signal from a control device 30, which will be described later, is installed at one end of the L drive shaft 16, and the rotation of the drive shaft 16 causes the base end 18a of the air duct 18 to be rotated.
is slid inside the curved part 11c of the intake pipe [1], and the length 1, n of the air duct 18 extending from the end lid of the curved part 1.1c of the intake pipe 11 can be made variable. .

Further, the tip end 1.8b of the air duct 18 is formed into a bell mouth shape and opens into the air chamber 13, so that even when the intake pipe length λn is the longest (fl wax), the curved portion of the intake pipe 11 A stopper (not shown) is provided to prevent it from coming off the edge.

Further, at a predetermined position on the side wall 13a in the air chamber 13, an intake pipe length longest detection sensor 20 made of an electromagnetic pick amplifier or the like is installed. When the position of 21 is detected, it is detected that the intake pipe length Ln of the air duct 18 is the longest (Jl max), and this signal is sent to the control device 3.
It is set to be output as 0.

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 1, an intake pipe pressure sensor 2 is installed near the intake valve 9 of the intake port 7 of each cylinder.
2 are installed respectively, and this intake pipe pressure sensor 2
Two output signals are output to the control device 30.

Further, a crank angle detection sensor 25 for detecting the crank angle is installed opposite to the crank rotor 24 provided on the crankshaft 23 of the engine 1, and a cam rotor 27 of the camshaft 26 is installed to discriminate between cylinders. The cam angle sensor 28 for
Output signals from the intake cam opening angle detection sensors consisting of eight intake cam opening angle detection sensors are each manually input to the control device 3o.

The control device 3o includes an intake pipe pressure sensor 22. Crank angle detection sensor 25. Cam angle sensor 28. Ignition switch 29. It receives the output signal from the longest intake pipe length detection sensor 20, performs arithmetic processing, and outputs a drive signal for forward or reverse rotation to the stepping motor 19.

Here, the control device 3o includes an I10 port 30a of an input/output interface, a CPU 30b that processes signals from the I10 port 30a, a ROM memory 30c that stores control programs, and an R memory that temporarily stores data.
The AM memory 30d etc. calculates and processes the driving force of the stepping motor 19 according to a predetermined program,
The drive signal is outputted from the drive circuit 30e to rotate the stepping motor 19 forward or reverse.

On the other hand, when the engine 1 has four cylinders, the crank rotor 24 has #1 cylinder as shown in FIG. #2 cylinder intake cam opening angle detection protrusion (slit may also be used) 24a,
The #3 and #34 cylinder intake cam opening angle detection protrusions 24b are provided, and the cam rotor 27 is provided with an ignition order #3
1. #3. #2. Cylinder t discrimination protrusion (slit temoyoi) 27a for distinguishing each cylinder according to #4
(1 piece), 27b (3 pieces).

27c (2 pieces) and 27d (4 pieces) are provided.

Further, the protrusions 24a, 24 of the crank rotor 24
The crank pulse signal from the crank angle sensor 25 that detected b and the protrusions 27a to 27 of the cam rotor 27
The cam pulse signal from the cam angle sensor 28 that detected d is set as shown in the timing chart of FIG. The pulse is set to represent the intake cam opening angle χ1 of the corresponding cylinder expressed 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, and shows the cam opening angle of the corresponding cylinder obtained from the crank angle detection sensor 25 and the cam angle sensor 28. Using the signal of χ1 as a trigger, the output signal of the intake pipe pressure sensor 22 installed near the intake valve 9 in the corresponding cylinder is sampled to detect the intake pipe pressure at the cam opening angle χ1, and the intake pipe pressure at the cam opening angle χ1 is detected. It is now possible to average the intake pipe pressure at the intake cam opening angle χ1 and change the intake pipe length 1n by driving the stepping motor 19 so that the intake pipe pressure P1 at this time becomes the maximum. ing.

Hereinafter, the operation of the control device configured as described above will be explained based on the block diagram shown in FIG. 6 and the flowchart shown in FIG. 7.

First, when the ignition switch 29 is turned on, the engine is started, the start state is determined by the start determination means 31 of the control device 30, and a normal rotation signal is output from the stepping motor drive means 32 to the stepping motor 19. . When the stepping motor 19 is driven in normal rotation,
In step S1, the rotation of the drive shaft 16 causes the air duct 1 to
B is rotated clockwise in FIG.
The longest intake pipe length detection sensor 2 installed on the side wall 13a of 3
0, the protrusion 21 of the drive shaft 1B faces the intake pipe length longest detection sensor 20, and a signal is outputted to the intake pipe length longest determination means 33. As a result, the intake pipe length maximum determining means 33 determines that the intake pipe length Jtn is the longest j! l1ax, and outputs a drive stop signal to the stepping motor 19 via the stepping motor drive means 32 to stop the stepping motor 19 at the longest position of the intake pipe length. Therefore, when starting the engine, the intake pipe length Jln is set to be the longest. From then on, the intake pipe length control by the start determination means 31 is not performed, but is controlled in step S2 and thereafter.

Next, in step S2, the crank angle detection sensor 25
The output signal (crank pulse) from the cam angle sensor 28 and the output signal (cam pulse) from the cam angle sensor 28 are sent to the cylinder discrimination means 34.
The cylinder is read and cylinders are identified. That is, the cylinder discrimination means 34 discriminates the cylinder by counting the number of cam pulses in the cam pulse group from the input of a crank pulse until the input of the next crank pulse, as shown in the timing chart of FIG. , outputs a cylinder discrimination signal to the intake pipe pressure calculation means 35. The intake pipe pressure calculation means 35 uses a trigger signal output from the trigger means 3B in synchronization with the output signal (crank pulse) of the crank angle sensor 28 to calculate the intake pipe pressure in the corresponding cylinder discriminated by the cylinder discrimination means 34. Read the output signal from the pipe pressure sensor 22 and start 1 cycle (engine 720 rotations)
By sampling the intake pipe pressure when the intake cam opening angle χ1 of each cylinder in , and averaging this, the intake pipe pressure P1 when the intake cam angle is the cam opening angle χ1 is obtained.
Calculate.

Note that in order to simplify the calculation of the intake pipe pressure P1 when the intake cam angle is the cam opening angle χ1, the intake pipe pressure P1 immediately upstream of the intake valve 9 is detected only at the intake port 7 in one cylinder. In addition to installing the intake pipe pressure sensor 22, a protrusion or slit-shaped detection portion is installed on the cam rotor 27 only at a portion corresponding to the cam opening angle χ1 in the one cylinder (#1 cylinder), and this is connected to the intake cam. It may be detected by the cam angle sensor 28 as an opening angle detection sensor and used as a trigger signal when reading the output signal from the intake pipe pressure sensor 22. According to this, the crank angle detection sensor 25. Further, the trigger means 36 and the cylinder discrimination means 34 of the control device 80 are unnecessary and simplified.

Next, in step S8, the intake pipe pressure "force P1" at the intake cam opening angle χ1 calculated in step S2 is expressed as:
Comparison standard data P. , D as storage means (RAM)
30d and output to the intake pipe pressure comparison means 38, where the intake pipe pressure P1 newly inputted from the intake pipe pressure calculation means 35 and the comparison reference data stored in the storage means 30d are outputted to the intake pipe pressure comparison means 38. POLD
A comparison is made with

Next, the process proceeds to step S4, where the output signal from the intake pipe pressure comparison means 38 is input to the stepping motor drive means 32, and the stepping motor drive means 32 outputs a signal for reversing the stepping motor 19 by one pitch.
The air duct 18 is rotated by a predetermined angle in the counterclockwise direction in FIG. 1 to shorten the intake pipe length An by one pitch. Next, the process proceeds to step S5, where the cam opening angle χ is newly determined based on the output signal from the intake pipe pressure sensor 22 when the cam angle is the cam opening angle.
The intake pipe pressure P1 at the time of 1 is calculated. and step S
In step 6, the comparison reference data POLD stored in the storage means 3od stored in step S3 and the intake pipe pressure P1 calculated in step S5 are compared by the intake pipe pressure comparison means 38, and if POLD≦P1, step Returning to S4, the intake pipe length 1n is further increased by 1 via the stepping motor 9 based on the output signal from the stepping motor driving means 32.
Shorten the pitch. On the other hand, in step S6 above, Poto
>PI, the process proceeds to step S7, where the output signal of the intake pipe length longest detection sensor 20 is read into the intake pipe length longest determination means 33, and it is determined whether the intake pipe length 1n is in the longest state.

If it is determined that the intake pipe length An is the longest, the process returns to step S4, and the intake pipe length is shortened by one pitch by the same operation as described above. On the other hand, if it is determined that the intake pipe length 1n is not the longest, the process advances from step S7 to step S8.

In step S8, a drive signal is output to the stepping motor 19 via the stepping motor drive means 32.

Then, the stepping motor 19 is rotated forward one pitch, and the air duct 18 is rotated by a predetermined angle in the clockwise direction in FIG. 2 to obtain the intake pipe length j! The process advances to step S9 by increasing n by one pitch, where the intake pipe pressure P1 for the intake cam opening angle χ1 is newly determined, and the process advances to step SIO.

In step SlO, the comparison reference data P stored in the storage means 30d in step S3 is stored. LD and the intake pipe pressure P1 at the intake cam opening angle χ1 detected after increasing the intake pipe length 2n by one pitch in step S9, and the intake pipe pressure comparing means 38 compares Po1. If o>Pl, the process returns to step S8, and the output signal from the stepping motor drive means 32 causes the intake pipe length j! Although n is further lengthened by one pitch, P
If OLD≦P1, the process returns to step S2, and the intake pipe pressure P1 at the intake cam opening angle χ1 is newly calculated, and the comparison reference data P is stored in the storage means 37 in step S3. Intake pipe pressure P1 obtained from LD in step S2
Update with.

Therefore, the intake pipe length J! is such that the intake pipe pressure P1 becomes maximum when the intake cam angle is the opening angle χ1! , n is controlled,
The volumetric efficiency of intake air improves in all operating conditions,
It is possible to improve engine output.

〔Effect of the invention〕

As explained in detail above, according to the present invention, each signal such as the intake pipe pressure installed near the intake valve in the intake port, the cam opening angle timing of the intake cam, and the intake pipe length at that point is received. The intake pipe length is calculated by the control device, and based on this, the intake pipe length is controlled to the optimum length so that the intake pipe pressure is maximized. The fresh air flows in,
Volumetric efficiency can be significantly improved.

In addition, when starting the engine, the intake pipe length is set to the longest, and the intake pipe length is changed to the optimum length in all operating ranges so that the intake pipe pressure according to the intake cam opening angle is maximized depending on the operating condition. Since the efficiency can be increased, the output of the engine can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a variable length intake pipe control device according to the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is an explanatory diagram showing the relationship between a crank rotor and a cam rotor. Fourth
Fig. 5 is a timing chart showing the relationship between cam pulses and crank pulses, Fig. 5 is an intake pipe pressure sensor near the intake valve of the engine, Fig. 6 is a block diagram showing the functions of the control device according to the present invention, and Fig. 7 is a FIG. 2 is a flowchart diagram of a control device for explaining the present invention in detail. ■...Engine, 3...Cylinder head, 7...
Intake port, 9... Intake valve, 11... Intake pipe,
lie...Bending portion, 12...Variable intake device, ■3.
... Air chamber, 16... Drive shaft, 18... Air duct, 19... Stepping motor, 20... Intake pipe length longest detection sensor, 22... Intake pipe pressure sensor,
25.28...Intake cam opening angle detection sensor (crank angle detection sensor, cam angle sensor), 3o...Control device. Patent Applicant Fuji Heavy Industries Co., Ltd. Agent Patent Attorney Nobu Kobashi Slag Volume

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 the length of the intake pipe is variable by forward or reverse rotation of a stepping motor in the intake pipe in the air chamber. In an engine having a variable length intake pipe device in which a variable length intake pipe is installed, an intake pipe pressure sensor installed near the intake valve of the engine, an intake cam opening angle detection sensor for detecting an intake cam opening angle, and a control device that receives the signal from the longest intake pipe length detection sensor and calculates the optimal intake pipe length.The intake pipe pressure at this time is determined by the intake cam opening angle obtained from the intake cam opening angle detection sensor. A control device for a variable length intake pipe characterized by controlling the length of the intake pipe so as to maximize the length of the intake pipe.