JPH0612061B2 - Intake method of internal combustion engine - Google Patents

Description

The present invention relates to an intake method for an automobile engine or the like.

(Prior Art) In a conventional automobile engine, one intake passage communicates with the intake port of each cylinder of the engine and the intake distribution chamber of the intake manifold. When the intake distribution chamber and the intake port are communicated with each other through a single intake passage as described above, the effective pipe length of the intake system cannot be changed in accordance with the low speed and high speed operation states of the engine, and the maximum charging efficiency is achieved in all operation regions. Will be difficult to obtain.

Therefore, the present applicant has proposed, as Japanese Patent Laid-Open No. 60-60258, an intake device in which the intake port of each cylinder and the intake distribution chamber are communicated not only by the intake passage but also by a bypass.

In the intake method using this intake device, the on-off valve provided in the bypass is closed in the low engine speed region, and intake is performed through the intake passage of a length that can maximize the charging efficiency in the low engine speed region. The opening / closing valve of the bypass is opened in the rotation region, and the intake is mainly performed by the bypass of the pipe length that maximizes the filling efficiency in the high rotation region.

(Problems to be Solved by the Invention) FIG. 5 is a graph showing the relationship between engine speed and torque. Line segment (a) shows the characteristics of the intake passage, and line segment (b) shows the opening of the bypass. The characteristics are shown below.

As is clear from this graph, for example, in the case of 1500 RPM or less, there is almost no difference between the torque characteristic due to the intake passage and the torque characteristic due to the bypass. Therefore, at 1500 RPM or less, even if the bypass opening / closing valve is closed, there is no special effect.

Nevertheless, in the past, since the bypass opening / closing valve is closed in all of the low speed rotation range, soot in the gas mixed in the intake air such as blow-by gas adheres to the opening / closing valve, which causes galling. Alternatively, it may cause a stick (malfunction).

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an intake method using an intake device provided with a bypass in addition to the intake passage, in an intake port of a cylinder and a single intake distribution chamber. Are independently connected to each other through an intake passage for low speed operation and a bypass for high speed rotation, and the intake passage for low speed operation is set to a length that can enhance filling efficiency during low speed operation. The high-speed operation bypass is set to a length that can enhance the charging efficiency during high-speed operation, and the high-speed operation bypass is provided with an opening / closing valve, so that the predetermined rotation is judged to be during high-speed operation. If the number of rotations is equal to or more than a certain number, the on-off valve is opened, and if the number of rotations is less than the predetermined number of rotations which is determined to be during low speed operation, the number of rotations is close to above the idling. The on-off valve is opened in the low opening range of the valve.

(Operation) When the rotational speed is below the idling speed and the throttle valve has a low opening, intake is performed through the intake passage and the bypass, and when the rotational speed is less than the predetermined rotational speed and is equal to or higher than the idling speed, the intake air is provided only through the intake passage. When the engine speed is equal to or higher than the predetermined rotation speed, the intake air is taken through the intake passage and the bypass. When the rotation speed is higher than the predetermined rotation speed, the intake air is dominated by the bypass having a small intake resistance.

(Example) Below, the Example of this invention is described based on an accompanying drawing.

FIG. 1 is a partially cutaway front view of a V-type 6-cylinder engine to which the intake method according to the present invention is applied, and FIG. 2 is a plan view of the same engine. The engine (1) includes a pair of cylinder rows (2), (3) is arranged parallel to the crankshaft, and each cylinder row (2), (3) is composed of three cylinders (4a) ... (4f), and between the cylinder rows (2), (3) Is formed with a V bank (5), and the intake ports (6a) ... (6f) facing the V bank (5) are provided in each cylinder (4a).
.. (4f), and an intake manifold (7) for distributing and supplying the air-fuel mixture to the cylinders (4a) ... (4f) is arranged in the V bank (5).

The intake manifold (7) has three parts along the axial direction of the crankshaft, that is, the first block (7a), the second block (7b) and an intermediate plate connecting the blocks (7a) and (7b).
It consists of (8). The intake manifold (7) has one common intake distribution chamber (9) and the intake passages (10a) ... (10f) extending from the distribution chamber (9) to the respective intake ports (6a) ... (6f). And bypasses (11a) ... (11f) extending from the intake distribution chamber (9) and opening in the middle of each intake passage (10a) ... (10f).

Here, the structure of a typical example of the intake passage and the bypass will be described with reference to FIG. 3 which is a longitudinal sectional view. The intake passage (10) has an intake distribution chamber () formed inside the second block (7b). 9) is opened on the lower surface, passes through the lower side of the intake distribution chamber (9) and turns upward, passes through the upper side of the intake distribution chamber (9) and the intermediate plate (8), and reaches the intake port (6), The bypass (11) opens to the side of the intake distribution chamber (9), penetrates the intermediate plate (8), and opens to the middle of the intake passage (10). The bypass (11) is not provided in the middle of any of the intake passages (10a) ... (10f) regardless of the representatives.
a) ... (11f) is open.

Further, each intake passage (10a) ... (10f) has a relatively small diameter, and its effective intake pipe length is a length that can maximize the charging efficiency during low-speed operation of the engine, and each bypass (11a) ... (11f) has a relatively large length. With a large diameter, the effective intake pipe length is the length that can maximize the charging efficiency during high-speed operation of the engine.
Inside a) ... (11f) are provided butterfly-type on-off valves (12a) ... (12f) that are opened and closed by an actuator (not shown).

An intake method when the intake device having the above-mentioned configuration is adopted will be described with reference to the flowchart of FIG.

First, it is determined whether the engine speed (Ne) is higher than a predetermined speed (N _BPS ). Here, the predetermined rotation speed refers to the minimum rotation speed when the engine is in the high-speed operation region, and is a value within the range of approximately 3500 to 4000 RPM when considered based on FIG. Then, the engine speed (Ne) is the predetermined speed.
Bypass (11) if determined to be higher than (N _BPS ).
Via the on-off valve (12) inside. Then, the air that has entered the intake distribution chamber (9) of the intake manifold (7) through the air cleaner is supplied to the intake port through the intake passage (10) and the bypass (11), but the bypass (11) Is the intake passage (10)
Intake resistance is small because the pipe length is short and large compared to, and the bypass (11) becomes dominant as the upstream intake pipe length,
The effective pipe length of the intake passage (10) is shortened. As a result, the effective pipe length has changed to a length at which the maximum filling efficiency is obtained during high-speed operation of the engine.

Since the fuel injection nozzle is provided near the intake port, the air-fuel mixture is supplied to the intake port.

On the other hand, when the engine speed (Ne) is lower than the predetermined speed (N _BPS ), it is determined whether the engine is idling or not.
Judge based on (Ne) and throttle valve opening.

When it is determined that the engine is not idling, specifically, in FIG. 5, the engine speed (Ne) is 1500 RPM <N.
When in the low speed operation region of e <N _BPS , the on-off valve (12) is closed and intake is performed only through the intake passage (10). Then, since the effective pipe length of the intake passage (10) is set so as to obtain the maximum filling efficiency during the low speed operation, the maximum torque can be obtained even during the low speed operation.

Further, when it is determined that the idling state, specifically, the fifth
In the figure, in the region lower than about 1500 RPM and in the low opening region of the throttle valve, the on-off valve (1
Open 2). In this region, torque does not change even if the on-off valve (12) is opened or closed. However, by opening the open / close valve (12), it is possible to prevent soot and the like from adhering to the open / close valve (12).

In the embodiment, it is determined whether or not it is in the idling state. However, if the opening of the throttle valve is small, the on-off valve may be opened without determining whether or not it is in the idling state. . This is because the engine torque is not required even when the engine speed is high in the operating state of the engine brake, and therefore opening the on-off valve does not affect the engine operation.

(Effects of the Invention) As described above, according to the present invention, in the intake device having the optimum effective pipe length in both the low speed and high speed operation regions, it is possible to reduce the rotation speed to less than the idling speed and the low opening region of the throttle valve. Since the on-off valve is opened in the region where the intake pipe length does not affect the torque characteristics, it is possible to prevent soot and the like from adhering to the on-off valve and prevent galling or sticking. Further, when idling, when intake noise is a concern, the operating noise of the injector or the like can be reduced by shortening the effective pipe length. When the engine speed is lower than the predetermined speed, which is judged to be during low-speed operation, the open / close valve is always closed to maintain the effective pipe length when the engine speed is near idling or higher (normal operation range). In such cases, the on-off valve does not operate repeatedly, so drivability such as responsiveness can be improved. Further, since the number of times the on-off valve is operated is reduced, the durability of the valve can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an intake device for carrying out the method of the present invention, FIG. 2 is a plan view of the intake device, FIG. 3 is a sectional view showing a relationship between an intake passage and a bypass, and FIG. The flowchart of the method of the invention, FIG. 5 is a graph showing the relationship between engine speed and torque. In the drawing, (1) is the engine, (6a) ... (6f) is the intake port,
(7) is an intake manifold, (10), (10a) ... (10f) are intake passages, (11), (11a) ... (11f) are bypasses, and (12) is an on-off valve.

Claims (1)

[Claims] 1. An intake passage for low speed operation, wherein the intake port of a cylinder and a single intake distribution chamber are independently provided to communicate with each other through an intake passage for low speed operation and a bypass for high speed operation. The road is set to a length that can enhance the filling efficiency during low-speed operation, the bypass for high-speed operation is set to a length that can enhance the filling efficiency during high-speed operation, and the bypass for high-speed operation is further set. An open / close valve is provided, and the open / close valve is opened at a predetermined rotation speed or higher determined to be during high-speed operation, and the open / close valve is opened at a rotation speed near idling or higher below the predetermined rotation speed determined to be during low-speed operation. An intake method for an internal combustion engine, wherein the on-off valve is closed, and the on-off valve is opened in a low opening region of the throttle valve which is lower than the rotational speed near idling.