JPH02215925A - Intake pipe for internal combustion engine - Google Patents

Abstract

PURPOSE:To effectively utilize intake pulsation over the whole area of operating ranges by opening or closing an on-off valve installed in an intermediate part of each interconnecting pipe connecting an outlet end of a volumetric part to an exhaust pipe main flow part according to an engine driving status. CONSTITUTION:There are provided volumetric parts 7-9 aside from an intake main flow part in such a way as to be connected to an intake pipe 5 in series by interconnecting pipes 10-12. Valves 13-15 installed in an intermediate part of these respective interconnecting pipes 10-12, are opened or closed via a controller 16 in accord with a driving condition. In brief, these valves are closed in order of 15, 14 and 13 in proportion as making engine speed go up, whereby characteristic frequency goes up and volumetric efficiency is improved for a resonance effect. With this constitution, intake pulsation is effectively utilized over the whole area of operating ranges, whereby the volumetric efficiency is increased and, a charging air quantity is also increased. Engine power can be thus improved over the whole area.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an intake pipe for an internal combustion engine.

[Conventional technology]

FIG. 3 shows an example of a structural diagram of an intake system of a conventional internal combustion engine. In the figure, 1 is an intake manifold, 2 is a surge tank, 3 is a throttle bidet, 4 is a throttle valve, 5 is an air intake pipe, and 6 is an air cleaner. The A end of the intake system is open to the atmosphere, and the B end communicates with the cylinder through a passage in the cylinder head, and is opened and closed by an intake valve (not shown).

Next, the operation of the conventional example will be explained.

During the intake stroke, air is sucked through the υA end by negative pressure generated by the downward movement of a piston (not shown).

This sucked air flows through the parts 6, 5, 4, 3°2
．． 1, passes through a cylinder head internal passage (not shown) from the B end, passes through the intake valve section, enters the cylinder, and is filled.

At this time, the amount of air inflow is adjusted by changing the opening degree of the throttle valve 4 depending on the operating conditions.

However, air is not inhaled as a steady flow, but because the negative pressure generated in the cylinder is repeatedly reflected at the open end of the volume, the atmosphere, and the valve, the air pulsates in the intake pipe, and is inhaled as an unsteady flow. be done. As the amount of air intake increases, that is, the volumetric efficiency increases, more fuel can be supplied and the output increases. For this reason, the length, diameter, and
Determining the volume.

[Problem that the invention seeks to solve]

In this manner, in the conventional example, the length and diameter of the entire intake system from the air cleaner to the intake valve are determined so that the volumetric efficiency is maximized due to pulsations within the intake pipe. However, there are times when it is not possible to make full use of the pulsation due to engine and loading constraints. Furthermore, even if pulsation can be exploited, the natural frequency of the entire system is fixed, and pulsation can only be exploited at a certain rotation speed and load, and if the operating conditions are deviated from, the volumetric efficiency will be adversely affected. It may also cause a decline.

The purpose of the present invention is to solve the problems of the conventional devices, and to improve the output of an internal combustion engine over the entire operating range by effectively utilizing intake pulsation, increasing the volumetric efficiency, and increasing the amount of charged air that enters the cylinder. Provides an intake pipe.

[Means to solve problems]

The intake pipe of the internal combustion engine according to the present invention includes a main stream portion of the intake pipe;
A plurality of volume parts provided separately: a communication pipe that connects these volume parts in series and connects its outlet end to the main flow part of the intake pipe; and a communication pipe provided in the middle of each of the communication pipes. The engine is characterized by comprising a pipe opening/closing valve; and a controller that opens and closes the opening/closing valve according to the operating conditions of the engine to vary the volume of the entire intake pipe.

[Effect]

With the configuration described above, the volume of the intake system is variable according to the operating conditions, so the pulsation of the intake air can be used effectively over the entire rotation speed range, improving volumetric efficiency over the entire range and increasing engine output. It becomes possible.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the present invention, as shown in FIG. 1, the main flow part of the intake air is connected to the intake/main inlet 5).

Valves 13, 14. are provided in the middle of each of the communicating pipes.
15 is provided, and a controller 16 is provided according to the operating conditions.
It is opened and closed through. The main part of this intake system is the same parts as the conventional example: intake manifold 1% surge tank 2,
The throttle is composed of a day 3, a throttle valve 4, an air intake/main valve 5, an air cleaner 6, and a passage in the cylinder head.

Next, the operation of the above embodiment will be explained.

At low speeds near certain rotational speeds N and l, all groups 13
．． 14.15 is opened and the volume part? , 8.9 all communicate with the main air intake part. For this reason, the natural frequency of the entire intake system is lower than when only the main intake part is used, and the volumetric efficiency can be increased due to the resonance effect near the rotational speed NEI. Next, the rotational speed increases and when the rotational speed approaches N□, the valve 15 is closed and the volumes 7 and 8 communicate with the main flow portion.

For this reason, compared to when the entire volume is in communication, the natural frequency is higher and a larger resonance is obtained at N□ where the rotational speed is higher than NEl, and the volumetric efficiency η is improved.

Next, when the rotation speed becomes even higher, the valve 14
is closed and only the volume portion 7 is in communication, the natural frequency further increases, and the volumetric efficiency η7 improves at the rotation speed N based on the same principle as above. Next, even higher rotation speed N! ,,
When this happens, the valve 13 closes and there is almost only the main flow of intake air, resulting in the original volumetric efficiency characteristic of the main flow.

The above explanation will be explained with reference to FIG. 2. The solid line (-) shows the relationship diagram between the volumetric efficiency and the rotational speed N0 in the case of the conventional example, that is, it is the volumetric efficiency characteristic that only the main flow part of the intake air has. When all the valves are open and the entire volume part communicates with the main flow part, the rotation speed is N8. In the vicinity, the volumetric efficiency η9 improves as indicated by the broken line <---) due to resonance. Next, when the valve 15 closes, the natural frequency increases and becomes as shown by a dashed line (-1-) near the rotational speed NEfl, and similarly the valve 14 closes at the rotational speed N0. In the vicinity, the volumetric efficiency η improves as shown by the two-dot chain line (-1--). Further, when all the valves 13° 14.15 are closed, the volumetric efficiency characteristic for only the main intake portion, ie, the solid line (-), becomes as described above.

Here, the valves 13, 14, and 15 are opened and closed as described above according to the rotational speed, and the total volume of the volume section provided separately from the main flow section is made variable. A volumetric efficiency characteristic with a similar envelope curve can be obtained, and the volumetric efficiency can be improved by taking advantage of resonance across the entire rotation speed range.

Note that these valves are opened and closed via a controller 16 to which a signal of engine rotational speed is input.

〔Effect of the invention〕

Since the present invention is configured as described above, the intake pulsation can be effectively utilized over the entire operating range, the volumetric efficiency is increased, and the amount of air charged into the cylinder is increased, so that the output can be improved over the entire operating range.

[Brief explanation of the drawing]

Figures 1 and 2 are related to the present invention; Figure 1 is a schematic diagram of the intake system of the embodiment, Figure 2 is a performance curve diagram obtained by the present invention, and Figure 3 is a diagram of the intake system of a conventional internal combustion engine. It is a diagram. 7.8.9...Multiple volume parts, 10, 11, 12
...Communication pipe, 13.14.15...Communication pipe opening/closing valve, 16...Controller.

Claims (1)

[Claims] A main flow section of the intake pipe; and a plurality of volume sections (7), (8), and (9) provided separately; the plurality of volume sections are connected in series, and the outlet end is connected to the main flow section of the intake pipe; Communication pipe (1
0), (11), and (12); communicating pipe opening/closing valves (13) and (14) provided at the intermediate portions of each of the communicating pipes, respectively;
, (15); and a controller (
16) An intake pipe for an internal combustion engine comprising: