JPH03189321A - Intake device of engine - Google Patents

Abstract

PURPOSE:To prevent respective chambers from being communicated with via a bypass when a control valve is closed at a low speed range and the like by closing an opening part at a downstream end of the bypass passage which communicates with the respective chambers of a surge tank by the control valve which divides the respective chambers. CONSTITUTION:A surge tank 14 divided into two chambers 241, 242 by a partition wall 20 and a control valve 22 is provided. The inside of the surge tanke 14 is changed over to communicated or partitioned conditions by opening/closing of the control valve 22 so as to vary the number of synchronized rotations. A downstream part of a bypass passage 30 is branched so as to connect downstream ends 301, 302 to chambers 241, 242. Opening parts of downstream ends 301, 302 are closed by the control valve 22 when the valve 22 is closed in the chambers 241, 242. Since the opening parts of the downstream ends 301, 302 are synchronizedly closed when the control valve 22 is closed at a low speed range and the like, the chambers 241, 242 are not mutually communicated through the bypass passage 30, and deviation in the number of syncthronized rotations rarely occur.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake system for a multi-cylinder engine.

[Conventional technology]

Conventionally, devices have been known in which a surge tank is provided in the intake manifold of an engine, and the interior of the surge tank is divided into two spaces by a partition wall and a control valve. In such an intake system, for example, when the engine is in a low or medium speed rotation range, the above control valve is closed and the equivalent pipe length of the intake system is lengthened, thereby lowering the tuned rotation speed and reducing inertia at low rotation speeds. In addition to increasing the supercharging effect, the control valve is opened at high speeds to shorten the equivalent pipe length, thereby increasing the tuned rotational speed and increasing the inertial supercharging effect at high speeds.

Furthermore, such a two-chamber split type intake system is provided with a bypass passage that bypasses the throttle valve and communicates the upstream side and downstream side (generally a surge tank) of the throttle valve. It has become known that the idling speed is precisely controlled by supplying auxiliary intake air and adjusting its flow rate (see Japanese Utility Model Publication No. 152731/1983).

[Problem to be solved by the invention]

In the above device, since the surge tank is divided into two chambers, it is difficult to connect the downstream end of the bypass passage to the center of the surge tank; in reality, it must be connected to one of the two chambers. No.

Therefore, the auxiliary intake air is supplied to the surge tank in a biased manner to one of the two chambers, and it is difficult to distribute it evenly. An effective countermeasure against this problem is to branch the downstream portion of the bypass passage into two and connect each downstream end to each chamber, but with this configuration, the control valve is closed and the surge Even if the compartments in the tank are isolated, these two chambers will be indirectly connected to each other via a bypass passage, which has the disadvantage of shifting the synchronized rotational speed and halving the resonance supercharging effect. .

In view of these circumstances, it is an object of the present invention to provide an engine intake device that has a simple structure, can evenly distribute auxiliary intake air, and can sufficiently obtain a resonant supercharging effect by changing the tuned rotation speed. With the goal.

[Means to solve the problem]

The present invention includes a surge tank divided into two chambers by a partition wall and a control valve, and is configured such that opening and closing of the control valve switches the interior of the surge tank between a communicating state and an isolated state, thereby changing the synchronized rotation speed. On the other hand, in an engine intake system in which a bypass passage is provided at a position that bypasses the throttle valve and communicates the upstream side and the downstream side thereof,
The downstream portion of the bypass passage is branched and each downstream end is connected to each chamber of the saji tank, and when the control valve is in a closed state in each chamber, the downstream end of the bypass passage is opened by the control valve. Each downstream end is placed in a position where the section is closed.

[For production]

In the above configuration, for example, by closing the control valve during low rotation, the two chambers in the surge tank are completely separated, and the equivalent pipe length of the intake system becomes longer. As a result, the tuned rotational speed is lowered, and the frequency of the intake vibration of the air column in the intake system is matched with the opening/closing cycle of the intake valve, resulting in resonant supercharging. Moreover,
At this time, the openings that are the joints between each chamber and the bypass passage are closed simultaneously by the control valve, so the chambers are not communicated with each other through the bypass passage, and there is almost no deviation in the synchronized rotation speed. .

On the other hand, for example, by opening the control valve in the high rotation range, the inside of the surge tank is communicated, the ventilation resistance is reduced, and the equivalent pipe length of the intake system is shortened, which increases the tuned rotation speed and increases the synchronized rotation speed in the low rotation range. The output will be improved as well.

〔Example〕

FIGS. 2 and 3 show the external appearance of an engine according to an embodiment of the present invention, and FIG. 1 is a schematic diagram thereof.

Here, a V-type 6-cylinder engine is shown.

The first to sixth cylinders of this engine body 10 are connected to a common saji tank 14 through independent intake pipes 121 to 126, respectively.
The cylinders are connected to the cylinders, and each cylinder is divided into 2.1 loops, which are not adjacent to each other in the order in which they undergo the combustion stroke.In other words, the three cylinders, the 1st cylinder, the 3rd cylinder, and the 5th cylinder, are connected to The cylinders are provided as an A group in a common bank, and three cylinders, the second cylinder, the fourth cylinder, and the sixth cylinder, are provided as a B group in a bank different from the above.

Further, an upstream intake pipe 18 is connected to the upstream side of the surge tank 14 via a throttle body 16.

As shown in FIG. 1, the inside of the surge tank 14 is divided into a left chamber 241 and a right chamber 242 by a partition wall 20 and a control valve 22.
1,123. ．． The cylinders of group A are connected to each other through 125, and independent intake pipes 122, 124, 126 are connected to the right chamber 242.
The cylinders of group B are connected through the cylinder. The control valve 22 is driven to open and close by an actuator 23 shown in FIG. 2 (see the solid line and two-dot chain line in FIG. 1). The rooms are connected to each other and each room 2 is closed.
41.242 are now isolated from each other.

On the other hand, inside the throttle body 16, the left ventricle 2
A first passage 261 communicating with the right ventricle 241 and a second passage 262 communicating with the right ventricle 242 are formed independently, and each passage 2
A throttle valve 28 is disposed within 61,262.

The upstream intake pipe 18 is connected to each passage 261 and 262.
are connected, and these upstream intake pipes 18 are gathered at a portion further upstream than the illustrated portion.

Further, in this engine, a bypass passage (hereinafter referred to as an ISC passage) 30 is provided at a position that bypasses the throttle valve 28 and communicates the upstream side and the downstream side thereof. Specifically, the upstream end of this ISO passage 30 is connected to the gathering part of the upstream intake pipe 18, and the downstream part branches into two downstream ends 301 and 302, each of which is connected to the left and right sides of the surge tank 14. Connected to rooms 241 and 242. A bypass valve (hereinafter referred to as an ISO valve) 32 is provided at an intermediate portion of this bypass passage 30, and this IS
By adjusting the air flow rate in the ISO passage 30 by the O valve 32, idle rotation speed control (IS
C; Idle 5peed C++nj+ol) is performed.

In addition, as a feature of this embodiment device, FIGS.
As shown in FIGS. (a) and (b), the downstream end 301 (302) of the bypass passage 30 is connected to the chamber 242 (241) on the opposite side of the chamber 241 (242) to which they are connected.
) is introduced into the interior from the bottom wall and rises upward.
Furthermore, it opens toward the chamber 241 (242) to be connected.

The connection positions of these downstream ends 301 and 302 are set so that their respective openings are simultaneously blocked from the front by the control valves 22 in the closed state as shown in FIG. 5(a).

Further, the actuator 23 and the IsC valve 32
The actuator (not shown) is connected to an ECU (not shown). This ECU controls the opening and closing of the multiple valves 22 and 30 based on the engine speed and engine load, and in this embodiment, control is performed as shown in the graph of FIG. 6.

Next, the operation of this engine will be explained.

First, in a low rotation and low load region such as during idling, the control valve 22 is opened and the ISC valve 32 is opened.

As a result, as shown in FIG. 5(b), the ISO
Each downstream end 301 and 302 of the passageway 30 is open, and each chamber 24
Auxiliary intake air (ISC air) is supplied within 1.242.

By adjusting the flow rate of the ISO air by ①SCSC2O3 degrees, the engine speed in this region is controlled.

Next, under high load conditions where a relatively high output is required even in the same low rotation range, the ISO valve 32 is closed and the control valve 22 is closed. As a result, each room 241.2
42 are isolated from each other, the equivalent pipe length becomes longer, and the tuned rotation speed at which a resonance effect is obtained is lowered. In this low rotation range, the frequency of the intake vibration of the air column and the opening/closing cycle of the intake valve are matched, and the engine output increases. improves. Moreover, at this time, as shown in FIG. 5(a), the openings at the downstream ends 301 and 302 of the ISO passage 30 are simultaneously closed by the control valve 22, so that the structure shown in FIG. (A structure in which only the ISO passage 30 is provided), the chambers 241 and 242 are not communicated by the ISC passage 30. That is, in the structure of this embodiment, each chamber 241, 242 is completely isolated by the control valve 22, and there is no deviation in the synchronized rotational speed due to the communication as described above.

On the other hand, in the high rotation range, by opening the control valve 22, the compartments 241 and 242 in the surge tank 14 are communicated with each other. This shortens the equivalent tube length, increases the tuning speed at which resonance effects can be achieved, and
Airflow resistance is reduced, which improves power output in the high rotation range. In addition, at this time, both chambers 241 and 242 are
Although they are also communicated through the O passage 30, since the pressure waves are propagated mainly through the surge tank 14, there is almost no effect on the tuned rotation speed.

As described above, in this engine, when the control valve 22 closes, the openings at the downstream ends 301 and 302 of the ISO passage 30 are closed by the control valve 22, so that deviations in the synchronized rotation speed can be prevented even in the low rotation range. High output can be obtained due to the resonance effect without any generation. Moreover, painting room 241.2
42 respectively at the downstream ends 301 and 302 of the ISO passage 30.
Since the downstream end is connected, ■S
C air can be distributed more evenly to each cylinder. Moreover, since each opening is closed simultaneously using the control valve 22, there is no need to provide a new valve, etc., and the above effects can be obtained with a simple structure.

In this embodiment, ■ Each downstream end 301 of the SC passage 30
, 302 are introduced into the inside of the surge tank 14 from the bottom wall thereof, but in the present invention, each downstream end 301,
As long as the opening of 302 is in a position where it can be closed by control valve 22, any connection structure may be used.

〔Effect of the invention〕

As described above, the present invention connects each chamber of the surge tank to the downstream end of the bypass passage that short-circuits the upstream and downstream sides of the throttle valve, and in each chamber, the control valve in the surge tank is in a closed state. This control valve closes the openings at each downstream end when the engine is in the low rotation range, so when the control valve closes in the low rotation range, the bypass passage does not communicate with each chamber. , there is no deviation in the tuned rotation speed.

Therefore, with a simple structure, it is possible to ensure high output through a sufficient resonant supercharging effect while uniformly distributing the auxiliary intake air through the bypass passage.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an intake system of an engine according to an embodiment of the present invention, FIG. 2 is a plan view showing the external appearance of the engine, FIG. 3 is a front view showing the external appearance of the engine, and FIG. FIG. 5(a) is a partial cross-sectional perspective view showing the main parts inside the surge tank in the same engine. FIG. 5(a) is a partial cross-sectional plan view showing the control valve in the surge tank in a closed state. FIG. A partial cross-sectional plan view showing a state in which the control valve is open in the same surge tank, Fig. 6 is a graph showing the details of the multi-valve opening/closing control performed in the above engine, and Fig. 7 is an example of a conventional engine intake system. FIG. 10... Engine body, 14... Surge tank, 2
0... Bulkhead, 22... Control valve, 241... Left ventricle,
242... Right ventricle, 28... Throttle valve, 30...
・ISO passage (bypass passage), 301, 302...
Downstream end of ISO passage, 32...ISC valve.

Claims (1)

[Claims] 1. It has a surge tank divided into two chambers by a partition wall and a control valve, and is configured so that the inside of the surge tank is switched between a communicating state and an isolated state by opening and closing the control valve, and the synchronized rotation speed changes. In an engine intake system in which a bypass passage is provided at a position that bypasses a throttle valve and communicates the upstream side and the downstream side thereof, the downstream portion of the bypass passage is branched and each downstream end is connected to each of the surge tanks. An engine characterized in that each downstream end of the bypass passage is connected to a chamber, and each downstream end is arranged at a position where an opening at the downstream end of the bypass passage is closed by the control valve when the control valve is in a closed state in each of the chambers. intake device.