JPS59173520A - Suction system for maltiple cylinder internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve volumetric efficiency by connecting the collecting part, etc. of a suction manifold to a volumetric part through a closing valve, in a system in which said suction manifold is divided according to a plural number of cylinder groups formed by collecting cylinders which do not ajoin each other in regard to their suction order. CONSTITUTION:When applied to a six-cylinder engine in which the suction order of each cylinder is, #1-#5-#3-#6-#2-#4, the cylinders are grouped in a first cylinder group 2a comprising #1 to #3 cylinders and a second cylinder group 2b comprising #4 to #6 cylinders. The upper course sides of the collecting parts 4a, 4b of the divided suction manifolds 2a, 2b are extended close to an air cleaner 6 through suction passage 5a, 5b and joined at a confluent part 7. A volumetric part 12 is provided between the collecting parts 4a, 4b and the confluent part 7, and each collecting part 4a, 4b and each suction pipe 5a, 5b is connected to the volumetric part 12 through openings 13a, 13b and 14a, 14b which are opened and closed by means of valves 15a, 15b and 16a, 16b respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable intake system for a multi-cylinder internal combustion engine, which controls fluctuations in intake pressure and improves the volumetric efficiency of the engine.

It is well known that the engine's volumetric efficiency (the ratio of the amount of intake air to the stroke volume of the cylinder) changes depending on the shape of the intake system of an internal combustion engine. One idea is to take advantage of this by varying the length, volume, etc. of the intake passage depending on the operating conditions of the engine to obtain high volumetric efficiency from low speeds to high speeds.

For example, in an intake system of a multi-cylinder internal combustion engine, the intake manifold is divided into a plurality of groups of cylinders whose intake orders are not adjacent to each other, and the intake passages from each intake manifold gathering part to the air cleaner are merged downstream of the air cleaner. An intake device has been proposed in which a plurality of intake passages are configured to communicate with each other, and the communication is cut off by a valve. However, since the intake passages are connected to each other without a volume part, there is a problem in that the pressure drop at the connection part is large during the intake stroke of the engine, and the intake inertia effect is not fully utilized in the high-speed range.

Hikari Dish ■ Kaisako's goal is to improve the volumetric efficiency in a wide speed range, especially in the high speed range, in a multi-cylinder internal combustion engine, thereby improving engine output and emissions.

A multi-cylinder internal combustion engine in which the bottomless intake manifold is divided into a plurality of cylinder groups whose intake orders are not adjacent to each other, and the intake passages from each intake manifold gathering part to the air cleaner are merged downstream of the air cleaner. In the intake device, the plurality of intake manifold gathering portions are connected to each other via the volume portion, and the intake passages are connected to each other via the volume portion between the intake manifold gathering portion and the intake passage merging portion. , a first valve for cutting off communication between the intake manifold gathering parts, and a second valve for cutting off communication between the intake passages, and these valves are controlled to open and close according to engine operating conditions. An intake device of the present invention is proposed.

The volume portion that communicates between the intake manifold gathering portions and the volume portion that communicates between the intake passages may be separate volume portions, or may be a common volume portion.

It is desirable that control is performed so that both valves are closed in the low speed range of the engine, the first valve is closed and the second valve is open in the middle speed range, and at least the first valve is opened in the high speed range.

In Figure 1, ■ is the main body of the 6-cylinder engine, 2 is the intake manifold, and 3 is the exhaust manifold.

The intake manifold 2 is grouped into a 10th cylinder group 2a and a 20th cylinder group 2b, which are not adjacent in intake order. That is, the intake order of each cylinder is #l-#5-#3-#
6-#2-. #4, and #1, #2, #3 are placed in the first cylinder group 2a, and #4. #
5. #6 are respectively grouped into the second cylinder group 2b. Gathering portion 4a of each divided intake manifold 2a, 2b
, 4b are provided with intake passages 5a, 5, respectively.
b to the air cleaner 6, and these intake passages 5a and 5b meet at a merging portion 7 downstream of the air cleaner 6. An air flow meter (not shown) is provided upstream of this merging portion 7 (downstream of the air cleaner 6). 1o is an intake duct of the air cleaner 6 that is open to the atmosphere 11.

A volume portion 12 is provided between the intake manifold gathering portions 4a, 4b and the intake passage merging portion 7 along the longitudinal direction of the intake passages 5a, 5b. Each intake manifold gathering part 4a
, 4b communicate with the volume portion 12 via openings 13a and 13b. Upstream of the intake manifold gathering parts 4a, 4b and downstream of the merging part 7, each intake passage 5a, 5b
opening 14a.

14b are provided, and these openings 14a, 14b also communicate with the volume 12. The openings 13a and 13b are valves 15a.

15b, and the openings 14a, '14b are connected to the valve 16.
Opening and closing are controlled by a and 16b, respectively. In addition, valve 1
5a.

As 15b, 16a, and 16b, known valves such as diaphragm control valves, electromagnetic valves, and hydraulic control valves that operate under negative pressure can be used.

FIG. 2 is a diagram showing the relationship between engine speed (rotational speed) and volumetric efficiency. In FIG. 2, solid line A indicates the volumetric efficiency when all valves 15a, 15b and 16a, 16b are closed. In this case, volume part 1
2 and openings 13a, 13b and 14a, 14b
This is the same as the situation where no . Dashed line B closes valves 15a and 15b and closes valve 16a.
, 16b shows the volumetric efficiency when opened.

In this case, the confluence position of the intake pressure waves is the opening 14a,
The effect is equivalent to that of moving downstream to the position 14b, and the volumetric efficiency peaks in the medium speed range. The dash-dotted line C shows the volumetric efficiency when the valves 15a and 15b are opened, and in this case, the effect is equivalent to moving the confluence position of the intake pressure waves further downstream to the openings 13a and 13b. As a result, the peak of volumetric efficiency shifts toward the high-speed region, and the value of the peak increases.

Note that when the valves 15a and 15b are open, most of the intake pressure waves are combined or reflected through the downstream openings 13a and 15b.
13b, valves 16a, 16
It is thought that opening and closing b does not have much effect.

In view of the above circumstances, as shown in FIG. 3, the valves 16a,
If the valve 16b is controlled to be closed in the low speed range and opened in the medium and high speed ranges, and the valves 15a and 15b are controlled to be closed in the low and medium speed ranges and opened in the high speed range, the volumetric efficiency will be As shown by the broken line in Figure 2, the volumetric efficiency can be increased over the entire speed range of the engine.

Note that the engine speed is detected by well-known means,
The signal is input to a control device (not shown), and the valve 15a is activated based on a command from the control device.

15b and valves 16a and 16b are controlled to open and close.

In a multi-cylinder internal combustion engine, it is possible to improve the volumetric efficiency over a wide range of engine speeds, thus improving engine performance and emissions.

Particularly, as shown by the shaded area X in FIG. 2, the improvement in volumetric efficiency is remarkable in the high speed range.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an intake system for a multi-cylinder internal combustion engine according to the present invention;
FIG. 2 is a diagram showing the relationship between engine speed and volumetric efficiency, and FIG. 3 is a diagram showing the opening and closing states of the valves. 2... Intake manifold, 4a, 4b... Intake manifold collection part, 5a, 5b... Intake passage, 7... Merging part, 10... Air cleaner, 12... Volume part, 1
3a, 13b. 14a, 14b-opening, 15a, 15b,
16a, 16b --- valve. Figure 1 Figure 2 Engine speed Figure 3 Engine speed

Claims (1)

[Scope of Claims] 1. A multi-cylinder internal combustion system in which the intake manifold is divided into a plurality of cylinder groups whose intake orders are not adjacent to each other, and the intake passages from each intake manifold gathering part to the air cleaner are merged downstream of the air cleaner. In the intake system of an engine, the plurality of intake manifold collecting parts are connected to each other via the volume part, and the intake passages are connected between the intake manifold collecting part and the intake passage merging part via the volume part. A first valve that communicates with each other and blocks communication between the intake manifold gathering parts, and a second valve that blocks communication between the intake passages, and these valves are opened and closed according to engine operating conditions. Controlled intake system. 2. The device according to claim 1, wherein the volume portion that communicates between the intake manifold gathering portions and the volume portion that communicates between the intake passages are configured as a common volume portion. 3. In the low speed range of the engine, both valves are closed, in the middle speed range, the first valve is closed and the second valve is open, and in the high speed range, at least the first valve is opened. Apparatus described in section.