JPS63198721A - Device for variable air intake pipe length for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain pertinent air intake pipe length at all times by moving a slide pipe depending upon an operation condition and adjusting the length of an air intake pipe via the provision of an air intake passage and a bellmouth within the air intake pipe and the installation of the slide pipe within the bellmouth. CONSTITUTION:When an engine is operated, a control unit 23 makes judgment about an operation condition on the basis of signals from each type of sensors. In this case, when the engine is operating at a low speed and a low load, a relay switch is turned ON, thereby making a vacuum tank 20 and a piston chamber 16 continuous to each other and moving a slide piston 13. And a slide pipe 11 is moved within a bellmouth part 10, and connected to the air intake passage 8 of an air intake pipe 5 and air introduced to a surge tank part via a throttle valve is fed to each cylinder. The length of the slide pipe 11 is thereby made relatively large and a fuel consumption rate is mainly improved. On the other hand, the slide piston 13 is retained at a constant position with a spring 17 at a high speed and a high load.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention is automatic! ■The length of the intake pipe is 8 [j
[Introducing a variable intake pipe stage device for an internal combustion engine.] [Prior art] In general, in a fuel-injected internal combustion engine, the 1-luke [well, depending on the length of the intake pipe, it is easily affected by the inertia of the intake air and the pulsation effect, so it should be made longer in the low speed range and shorter by 1 in the high speed range. This makes it possible to improve the torque by 1-lux in each operating range. Therefore, in the past, various devices have been devised in which the length of the intake pipe is made variable in order to achieve proper intake inertia and pulsation effect.For example, as an example suitable for natural intake,
As shown in Japanese Unexamined Patent Publication No. 59-101535, an intake expansion chamber provided in an intake passage communicating with the atmosphere is divided into two, and the engine side passage is formed to be expandable and contractable by negative pressure in the intake pipe. As an example suitable for a supercharger 6j engine, as shown in Japanese Utility Model Application Publication No. 58-181931'?j, the length of the resonance passage section is adjusted by sliding the i1 dynamic resonance tube according to the boost pressure. [Problems to be solved by the invention] However, in the prior art mentioned above, in the case of department names, link! The structure is complicated and operation reliability is poor, and in multi-cylinder engines, the engine side passage in each intake passage is
Because it has a structure that expands and contracts with one diaphragm,
The problem is that it requires precision in the positional relationship of the tube axes, etc. by machining the outer and inner tubes, and is not very suitable for reconnaissance.In the latter case, depending on the boost pressure Since the length of the resonance passage section is variable, it is naturally not applicable to naturally aspirated engines.The present invention has been made in view of the above-mentioned circumstances.
An intake passage section and a bell mouth section are provided inside the intake pipe, and by combining these with a variable intake pipe length mechanism, the intake pipe length is controlled according to the operating conditions from low speed range to high speed range.
A variable intake pipe length device for an internal combustion engine is provided for the purpose of improving torque due to intake inertia and pulsation effect. [Means for Solving the Problems] In order to achieve the above object, the present invention provides an intake passage having a tapered tapered surface on the engine side of the intake pipe connected to the intake boat of the cylinder head. A surge tank part is integrally formed with the throttle valve copper of the intake pipe, and a bell mouth part is installed in the surge tank part facing the intake passage part, and in the bell mouth part, The old VJ pipe with a tapered surface formed at the tip on the intake passage side is slidably inserted, and a sliding piston that slides inside the cylinder via a piston rod is installed at the rear end of the sliding pipe. At the same time, a screw chamber is formed between the partition wall supporting the piston rod and the sliding piston, and a spring interposed in the piston blank space,
The above-mentioned sliding pipe is urged in a direction away from the intake passage of the intake pipe, and 1. At low speeds of the engine, in communication with the tank or atmosphere,
Only at low loads 11,1, the solenoid valve is controlled to apply negative pressure to the piston chamber.1. [This is constructed by connecting the sliding pipe and the intake passage portion of the intake pipe. (Function) Based on the above configuration, according to the present invention, an intake passage portion and a bell mouth portion are provided in the intake pipe of the engine, and
A sliding pipe of ms is installed in the bell mouth pipe, and the sliding pipe is connected to the intake passage only at low speeds and low loads of the engine to increase the length of the intake pipe. It is possible to set an appropriate intake pipe length in the entire operating range, and it is possible to obtain the effect of intake inertia and pulsation, and it is possible to improve the output. (Example) Hereinafter, an example according to the present invention will be described in detail based on the attached drawings. Fig. 1 is a part showing a variable intake pipe length device for a four-cylinder internal combustion engine, which is an example according to the present invention. The broken plan view and Figure 2 are cross-sectional views taken along the line ■-■ in Figure 1.
2 indicates a cylinder head of an internal combustion engine, 2 indicates a combustion chamber of each cylinder, 3 indicates an intake valve, 4 indicates an exhaust valve, 5 indicates an intake pipe, and 6 indicates a throttle valve. An intake passage portion 8 having a tapered taper angle θ is formed on the engine side of the intake pipe 5 connected to each intake boat 7 of the cylinder head 1, and this intake passage portion 8 has a tapered surface 8a. It is provided. Further, a surge tank portion 9 is integrally provided on the side of the throttle valves 1 to 6 of the intake pipe 5, and a bell mouth is provided in the surge tank portion 9, facing the intake passage portion 8 of each cylinder. The section 10 is IFFed. A sliding tube 11 having a tapered surface 11a formed on the outer periphery of the tip on the side of the intake passage section 8 is slidably fitted into the cylinder of the bell mouth section 10. The opening piston 13 is installed in the cylinder 14 via the screw and rod 12 which are fixed together.
The sliding piston 13 is connected to the partition wall 15 [! l fJJ
The spring 17 interposed in the piston chamber 1G formed between the pistons 13 is normally set at a position away from the intake passage section 8 of the intake pipe 5 (X1). 5 is provided with a negative pressure takeoff via 118, and this zero pressure takeoff via 18 is connected to the piston chamber 1 via a one-way valve 19, a negative pressure tank 20, and a solenoid valve 21.
The pressure inside the piston chamber 1G is controlled by communicating with the inside of the piston chamber 1G and by opening the atmosphere to the atmosphere 1]22 through the solenoid valve 21 and switching the above N solenoid valve 21 with a signal from the control unit 23. It is supposed to be adjusted. In the figure, reference numeral 24 is a seal for the piston rod 12 provided on the partition wall 15, which prevents air leakage between the surge tank portion 9 and the piston chamber 1G. Also 1
4aia This is an air handling hole that keeps the inside of the cylinder 14 at an atmospheric pressure of 1.5 to 7. Here, the 7ff solenoid valve 21 is controlled by ff1lI.
As shown in FIG. 32, the Konitz 1-23 is composed of a microcomputer, etc., and when the relay switch 25 is turned ON1 by a signal from the control unit 23, the individual power supply 2G is applied to the coil of the solenoid valve 21. 21a is excited, so normally (1 pressure tank 20 side is closed and the screw [・n?
The valve body 2112 that opens the air vent 16 to the atmosphere opens the air port 22 to communicate the negative pressure tank 20 and the piston chamber 1G, and slides the active screw 13 against the spring 17 with resistance i). As shown in Figure 2, the tip of the m-flow tube 11 is inhaled? It is connected to the intake passage section 8 of No. 15. The control unit 23 controls the engine rotation speed sensor 27 installed in the engine's:
A signal from the suction pipe pressure hinge J28 that detects the suction pipe negative pressure is input to the rotation speed frame output section 30 and the suction pipe pressure output group 31 of the control unit 23, respectively. Suction pipe pressure P/J< is lowered. The above rotation'r! l1g output section 30 and suction pipe pressure retrieval section 3
The output signal from 1 is input to the table search unit 32, which performs a table lookup as shown in FIG. It is determined whether the pressure P is deeper than the specified value pc at low load, and only at low speed and low load, the table search section 32 outputs a signal to the output circuit 33, and the relay switch 25
Turn on? Ill. In addition, in the control unit 23, when the engine is at a low speed and other than the low load 114, the signal from the table search section 32 is not output and there is no output signal 3 from the output circuit 33, so the relay switch 25 is turned OFF. state, 1
! The valve body 21b of the magnetic valve 21 is biased by a spring 21C to close the passage on the negative pressure tank 20 side and open the screw chamber 16 to the atmosphere. Next, the operation of the variable intake pipe length device according to the present invention configured as described above will be explained as shown in FIG.
I will explain next. First, when the engine is operated, in step S1, the number of engine rotations is determined by the engine speed sensor 27 and the suction pipe pressure sensor 28.
The engine speed N and suction pipe pressure P are calculated based on the output signal from the
A table look-up is carried out based on the engine rotation number N and the suction pipe pressure P which are weighted against the standard suction pipe pressure [)C, and it is determined in step S3 whether it is a low speed, low load region or a high speed, high load region. If the judgment in step S3 is that the speed is low and the load is low, the control unit 23 outputs a signal to turn on the relay switch 25 and helirace switch 25 in step S4, and when the relay switch 25 turns 0N1J, the solenoid valve 21 is activated and negative pressure is generated. The tank 20 and the piston chamber 16 are made to communicate with each other, and a negative Ft is introduced into the piston chamber 1G to close the sliding screw 1hen 1.
3 is moved from the state shown in FIG. 1 to the state shown in FIG. 2 as shown. Along with this, the sliding pipe 11 is connected to the intake passage section 8 of the intake pipe 5 by sliding within the bell mouth section 10, and introduced into the fluid tank section 9 via the throttle valve 6. Intake air (well, it is sucked into each cylinder from the rear of the bell mouth part 10. At this time, the intake f~ length is (12>I!, i), and if FJ Shokei 11 is not connected, Intake pipe length J
! , can be made more beautiful than 1. Further, if the engine is operating in the high-speed, high-negative range as determined in step S3, no signal is output from the control unit 23 to the relay switch 25 in step S5, and therefore the relay switch 25 is turned OFF. δ
The magnetic valve 21 is not activated, and the inside of the piston chamber 1G is open to the atmosphere. Therefore, the J learning piston 13 is held in the state shown in FIG. 1 by the biasing force of the spring 17, and intake air is drawn directly into each cylinder from the intake passage section 8 of the intake pipe 5, so that the length of the intake pipe is 11. [Effects of the Invention] As explained above in detail, the variable intake pipe length #& position of the internal combustion engine according to the present invention allows the intake pipe length to be lengthened at low speeds and low f1'fjJ depending on the operating condition of the engine. ,high speed,
For high load (1r), the intake pipe length is set short, and the intake pipe length is set to a single length, which improves the fuel efficiency in the low speed and low load range compared to the conventional engine. It is possible to improve output in all operating ranges. Further, according to the present invention, an intake passage section and a bell mouth section are provided inside the intake pipe, and a variable intake pipe length device in which an IJ pipe is installed is combined with this, and one device is provided for each cylinder. Due to the simple structure, the reliability of the structure is higher than that of a variable intake pipe length S1i arrangement using a conventional link mechanism, etc., and it is possible to improve the intake capacity and the output.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view showing a variable intake pipe length device for a four-cylinder internal combustion engine which is an embodiment of the present invention, FIG. 2 is a sectional view taken along line U-II in FIG. 1, and FIG. FIG. 4 is an explanatory diagram showing the control unit according to the present invention (FIG. 4 is a characteristic diagram of the table lookup section in the control unit, and FIG. 5 is a one-shot diagram showing the operation according to the present invention). ... Intake pipe, 6... Throttle valve, 8... Intake passage section, 8a... Taber surface, 9... Surge tank section, 10... Bell mouth section, 11... Opening pipe , 11a
...Taber surface, 13...Opening piston, 14...
Cylinder, 15... Partition wall, 1G... Piston chamber,
17...Spring, 19...One-way valve, 20...
- Negative control unit, 21... Solenoid valve, 23... Control unit. Patent Attorney Susumu Murai Figure 5

Claims (1)

[Claims] An intake passage portion having a tapered surface is formed on the engine side of the intake pipe connected to the intake boat of the cylinder head, and a surge tank portion is integrally formed on the throttle valve side of the intake pipe. a bell mouth portion facing the intake passage portion is installed in the surge tank portion;
A sliding tube having a tapered surface at its tip on the side of the intake passage is slidably inserted into the bell mouth portion, and the sliding tube slides inside the cylinder via a piston rod at the rear end of the sliding tube. A sliding piston is installed, and a piston chamber is formed between the sliding piston and a partition wall that supports the piston rod, and a spring interposed in the piston chamber allows the sliding pipe to be moved from the intake passage of the intake pipe. At the same time, the piston chamber is communicated with the negative pressure tank storing the intake pipe negative pressure or the atmosphere through a solenoid valve controlled by the control unit, and only when the engine is running at low speed and under low load. A variable intake pipe length device for an internal combustion engine, characterized in that the solenoid valve is controlled to apply a negative pressure to the piston chamber, thereby connecting the sliding pipe and an intake passage of an intake pipe.