JPS62288321A - Suction device for multicylinder engine - Google Patents

Abstract

PURPOSE:To improve suction efficiency, by a method wherein, at the time when the opening timing of a rotary valve opened and closed in linkage with rotation of an engine located upstream a suction port is delayed under the given running state of an engine, the more the number of revolutions is decreased, the more the closing timing thereof is increased. CONSTITUTION:A rotary valve 24 rotated in linkaged with rotation of a crank shaft 5 is provided upstream a suction port 15, and a volume chamber 14 reflecting auction pulsation is provided upstream the rotatry valve. The rotational phase of the rotary valve 24 to the crank shaft 5 is regulated according to the running state of an engine by means of a control device. During low rotation in that the opening timing of the rotary valve is delayed, the more the number of revolutions is decreased, the more the closing timing of the rotary valve is increased, and this constitution eliminates the influence exercised by suction pulsation of other cylinder.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an intake system for a multi-cylinder engine that achieves an intake inertia effect.

(Prior art) In the engine intake system, there is a
As shown in Publication No. 18, the intake port is provided in an intake passage upstream of an intake port that opens and closes in synchronization with engine rotation, and is opened later than the opening timing of the intake port at least when the engine is under high load and low rotation speed, a rotary valve that opens after this point to delay the intake start timing; and an inversion section that is provided in the intake passage upstream of the rotary valve and that reverses the intake negative pressure wave that occurs downstream of the rotary valve when the rotary valve opens. Some engines are equipped with such a system that the amplitude of the change in intake pressure is increased to enhance the intake inertia effect, particularly under high load and low rotation, thereby increasing the charging efficiency, that is, the engine torque. Furthermore, by providing an advance mechanism that advances the opening timing of the rotary valve according to the engine speed, the rotary valve actively obtains the intake inertia effect in the low engine speed range, while the engine already has a large intake inertia effect. In the high rotation range, the opening timing is advanced to prevent the rotary valve from creating intake resistance, that is, to minimize pumping loss.

(Problem to be Solved by the Invention) By the way, the opening period of the rotary valve is generally set to be approximately the same as the opening period of the intake port in order to ensure a sufficient intake period during high engine speeds. It is. Therefore, if the opening timing of the rotary valve is delayed, the intake end timing will inevitably be determined by the closing timing of the intake port. The closing timing of the intake port is normally set to be much later than the intake bottom dead center.

Here, we are currently using a 4-cycle in-line 4-cylinder engine, and the ignition order is 1.
Assuming the carrot of 3 and 4.2, even if the opening timing of the rotary valve is delayed, due to the above-mentioned reasons, the intake of the next No. 3 cylinder must start before the intake of the No. 1 cylinder ends. There is. However, when the ignition order, that is, the intake timing overlaps between adjacent cylinders in the intake stroke, interference between the cylinders causes the intake inertia effect in the cylinder immediately before the end of intake to be affected by the next cylinder whose rotary valve begins to open. The problem was that the system would be weakened. The adverse effects caused by this interference of intake air between cylinders become more pronounced as the engine rotational speed decreases and the intake air flow velocity decreases.

Therefore, an object of the present invention is to prevent the adverse effects of intake air interference between cylinders when obtaining an intake inertia effect using a rotary valve, so that this intake inertia effect can always be fully utilized. An object of the present invention is to provide an intake system for a multi-cylinder engine.

(Means and operations for solving the problem) In order to achieve the above-mentioned object, the present invention provides an air intake inertia effect, at least under high load and low rotation, and the lower the engine rotation speed, the more the rotary valve opens. The idea is to shorten the period and bring the closing date earlier. in particular.

Provided in the intake passage upstream of the intake port that opens and closes in synchronization with the rotation of the engine, and opens later than the opening timing of the intake port and after the intake top dead center at least when the engine is under high load and low rotational speed to start the intake. a rotary valve that delays the opening period of the rotary valve; an inversion part that is provided in the intake passage upstream of the rotary pulp and that reverses the intake negative pressure wave that is generated downstream of the rotary valve when the rotary valve opens; an opening period adjusting means for adjusting the closing timing of the rotary valve; and an opening period adjusting means for controlling the opening period adjusting means in the region where the intake start timing is delayed to adjust the closing timing of the rotary valve as the engine speed is lower. The configuration includes a control means for accelerating the speed, and the following.

With such a configuration, it is possible to effectively generate an intake inertia effect according to the engine speed and ensure the intake period to be as long as possible, thereby improving the filling efficiency as a whole.

(Example) Examples of the present invention will be described below based on the attached drawings.

In FIG. 1, l is a 4-stroke, in-line 4-cylinder engine, which is a reciprocating type in which a crankshaft 5 is rotationally driven via a connecting rod 4 by the reciprocating motion of a piston 3 fitted into a cylinder 2. It belongs to The combustion chamber 6 defined by the piston 3 has an intake port 7 and an exhaust port 8.
is opened, the intake port 7 is opened and closed by an intake valve 9, and the exhaust port 8 is opened and closed by an exhaust valve 10 at known timings in synchronization with the rotation of the crankshaft 5. That is, the opening/closing timing of the intake valve 9 is as shown in FIG.

An intake passage 11 connected to the intake port 7 is an air crevice 1.
one common passage 13 extending from 2, a surge tank 14 as a reversal section provided in the middle of the common passage 13, and an independent passage 15 that extends from the surge tank 14 to the intake port 7 of each cylinder 2. It is equipped with and,
In the common intake passage 13 upstream of the surge tank 14,
An air flow meter 16 and a throttle valve 17 are provided, and each independent passage 15 is provided with a fuel injection valve 18.

A rotary valve 21 is provided in the independent passage 15. As shown in FIG. 2, the rotary valve 21 includes a casing 22 that is integrally formed with each independent passage 15 and extends in the cylinder arrangement direction, and a rotor that is rotatably disposed inside the casing 22 via a bearing 23. 24. In the embodiment, the rotor 24 is a cylindrical body with a bottom, and intake air is supplied into the rotor 24 from an open end thereof. The rotor 24 has four communication ports 25 opened in its open surface, corresponding to the positions of the independent intake passages 15, and the number of which corresponds to the number of cylinders 2. Such a rotor 24 is linked to the crankshaft 5 so that it rotates once for every two revolutions of the crankshaft 5, as will be described later. Then, the ignition order of each cylinder 2 is from the right side to the left side in FIG. 2
The order is C→2d→2b. Therefore, due to the relationship of the rotational speed and the ignition order, the communication ports 25 of the second cylinder 2b and the third cylinder 2c are connected to the rotor with respect to the communication ports 25 of the first cylinder 2a and the fourth cylinder 2d. Circumferential direction of 24 18
They are formed with a phase difference of 0°.

The communication ports 25 of the rotor 24 are each larger in opening width than the independent passage 15 in the axial direction of the rotor 24 . Further, the end of the communication port 25 on the lag side in the rotational direction of the rotor 24 is an inclined surface 25a. The rotor 24, together with its bearing 23, is attached to the casing 22.
It can be displaced by a predetermined amount in the axial direction along a guide 22a formed in the axial direction. As a result, the communication port 25 and the independent passage 15 change according to the axial displacement of the rotor 24.
The opening period of the rotary valve 21 communicating with the rotary valve 21, that is, the closing timing of the rotary valve 21 is adjusted.

Note that the first rotor 24 is biased by a spring 26 to the state shown in FIG. 2 in which the opening period is the longest.

a- The rotor 24 of the tally valve 21 is connected to the crankshaft 5
It is designed to be mechanically driven via an advance angle mechanism 27. That is, the advance mechanism 27
A first helical gear 28 formed at one end of 4, and a second helical gear 3 disposed axially opposite to the first helical gear 28 and attached to a pulley 29.
0, a timing belt 32 is stretched between the pulley 29 and a pulley 31 provided on the crankshaft 5, and the pulley 29 is driven to rotate by the crankshaft 5 at the rotational speed of that station. ing. Both helical gears 28 and 3 above
0, the adjustment piece 33 is engaged with the adjustment piece 33.
By displacing 7I in the axial direction of the rotor 24,
The relative rotational position (advance amount) of the first helical gear 28 (that is, the rotor 24) with respect to the S2 helical gear 29 (that is, the crankshaft 5) is changed. The drive displacement of the swing lever 3
This is performed by the first motor 35 via the motor 4.

Further, a sleeve 36 is fitted into the casing 22 on one end surface side of the bearing 23 that supports the first rotor 24 in a slidable but non-rotatable manner. This sleeve 36 has a tooth portion 36a that meshes with a helical gear 37, and by rotating the helical gear 37 in a predetermined direction by a second motor 38, the sleeve 36 is displaced to the left in FIG. As a result, the rotor 24 itself can be moved to the left in FIG. 2 against the spring 26. vice versa,
When the helical gear 37 is rotated in the other direction, the rotor 24 is moved to the left in FIG. 2 by the action of the spring 26.

41 in FIG. 2 is a control unit, and this control unit 41
Signals are input from a rotation speed sensor 42 that detects the engine rotation speed and a load sensor 43 that detects the engine load. Further, this control unit 41 outputs an output to both the first and second motors 35 and 38.

Now, next, both motors 35 and 38 by the control unit 41
The contents of control, that is, advance control of the opening timing of the rotary valve 21 and control of the opening period, that is, the closing timing, of the rotary valve 21 will be explained.

First, when the engine is running at high speed, the opening timing of the rotary valve 21 almost coincides with the opening timing of the intake valve 9. The closing timing of the rotary valve 21 is in the longest state [the rotor 24 is at the right stroke end in FIG. Ru.

Now, when the engine speed is below a predetermined value and the engine load is above a predetermined value, the opening timing of the rotary valve 21 is later than the opening timing of the intake valve 9 and the intake top dead, as shown in FIG. point (TDC). As a result, the independent intake passage 15 downstream of the rotary valve 21
The intake negative pressure wave generated within the cylinder 2 is reversed by the surge tank 14 to become a positive pressure wave, which is introduced into the cylinder 2. At this time, as the engine speed becomes lower, the rotor 24 is displaced to the left in FIG. 2, and the closing timing of the rotary valve 21 is made earlier than the closing timing of the intake valve 9. When the engine speed is extremely low, when the rotary valve 21 is opened in a certain cylinder 2 (No. 3 cylinder 2c in FIG. 3), the rotary valve 21 of the previous cylinder 2 (No. 1 cylinder 2a in FIG. 3) is opened. 21 has already been closed. That is, when focusing on cylinders with adjacent ignition orders, the overlap in their intake timings becomes smaller as the engine speed decreases, as shown in FIG. 4, and eventually the amount of overlap becomes zero.

Here, in FIG. 3, the maximum opening period of the rotary valve 21 is shown as 1, and an example of the opening period that is reduced by advancing the closing timing is shown as 22. Further, the amount of overlap between adjacent cylinders when the closing timing of the rotary valve 21 is not advanced in any way is indicated by 13, and the amount of overlap in FIG. 4 means this sentence 3.

In the case of the embodiment, when the rotor 24 is displaced in the axial direction, the rotational phase relative to the crankshaft 5 (rotary valve 2
1) is shifted, the advance angle mechanism 27 is adjusted to compensate for this shift.

Although the embodiments have been described above, the present invention can be similarly applied to diesel engines. Furthermore, the invention is not limited to reciprocating engines, and can be similarly applied to rotary piston engines whose intake ports are opened and closed by a rotor. Further, the closing timing of the rotary valve 21 may be adjusted by forming an inclined surface corresponding to the inclined surface of the communication port 25 on the casing 22. This can also be achieved by providing the casing 22 separately from the independent intake passage 15 and displacing the casing 22 in the axial direction with respect to the rotor 24. Of course, when the surge tank 14 is not used, the part of the air cleaner 12, that is, the atmosphere, can be used as the inversion part of the intake negative pressure wave.

(Effects of the Invention) As is clear from the above description, the present invention can always effectively improve charging efficiency due to the intake inertia effect by preventing the adverse effects of intake air interference between cylinders.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a detailed sectional view taken along line II--II in FIG. 1. FIG. 3 is a graph showing the opening/closing timing of rotary valves and intake valves for cylinders with adjacent firing orders. FIG. 4 is a graph showing the amount of overlap in intake timing between cylinders with adjacent ignition orders. 1: Engine body 2 Two cylinders 6: Combustion chamber 7: Intake port 9: Intake valve ll: Intake passage 13: Common intake passage 14: Surge tank (reversed part) 15: Independent intake passage 21 = rotary/<-lube 22: Casing 24: Rotor 25: Communication port 25a: Inclined surface (for adjusting closing time) -27:
Advance angle mechanism (for opening timing adjustment) 35. 38: Motor 41: Control unit 42 Knee i! Sensor (engine speed) 43: Sensor (engine load)

Claims (1)

[Claims] (1) Provided in the intake passage upstream of an intake port that opens and closes in synchronization with engine rotation, and opens later than the opening timing of the intake port and after intake top dead center at least when the engine is under high load and at low engine speeds. a rotary valve that delays the intake start timing; an inversion section that is provided in the intake passage upstream of the rotary valve and that reverses the intake negative pressure wave that occurs downstream of the rotary valve when the rotary valve opens; and an opening of the rotary valve. an opening period adjustment means that adjusts the closing timing of the rotary valve by adjusting the period; and an opening period adjustment means that controls the opening period adjustment means in the region where the intake start timing is delayed, so that the lower the engine speed, the more the rotary valve closes. An intake system for a multi-cylinder engine, comprising: a control means for advancing the closing timing;