JPS61255218A - Intake device of engine - Google Patents

Abstract

PURPOSE:To facilitate production of high swirl and to improve combustion efficiency, according to the method wherein the intake valve of an auxiliary intake port is further delayed for control than the closing timing of the intake valve of a main intake port according to the operation condition of an engine, and blowing-back fuel-air mixture from a cylinder at a preceding stage can be introduced to a cylinder at a following stage. CONSTITUTION:In a 4-cylinder engine, cylinders 1-4 are provided with exhaust ports 1E-4E, main intake ports 1P-4P, each positioned in a position allowing promotion of formation of a swirl, and relatively large auxiliary intake ports 1S-4S, respectively, each positioned in a position adjoining to the main intake port. Communicating ports 11-14, through each of which the auxiliary intake port at a preceding stage is connected to the main intake port at a following stage in relation to the ignition order of each cylinder, are provided. Auxiliary intake valves 1S2-4S2, the closing timings of which are further delayed than those of main intake valves 1P1-4P1 during middle and low load range, are mounted to the auxiliary intake ports 1S-4S, and shutter valves 1S3-4S3, closed during low speed running, are mounted in auxiliary intake pipes 1S1-4S4.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine intake system.

(Prior Art) In an engine, for example, a gasoline engine for an automobile, the accelerator opening degree is adjusted in accordance with load conditions on the engine such as during running or idling to control the operating characteristics of the engine.

The accelerator opening degree is adjusted by controlling the amount of air-fuel mixture taken in by an intake valve that throttles the intake passage in accordance with the amount by which the accelerator is depressed.

(Problems to be Solved and Attempted by the Invention) In the above-mentioned engine load control by adjusting the accelerator opening degree, since the intake air is throttled by the intake valve, there is a risk of causing an intake loss.

Specifically, the current situation is that this suction loss accounts for about 12% of the 10-mode fuel efficiency, and is one of the causes of worsening fuel efficiency.

Moreover, in conventionally known engines, a pumping action occurs during the intake stroke when the intake valve closes when air is taken into the cylinder, especially in a low load range, and this action also has drawbacks. there were.

In other words, the negative pressure generated by the lowering of the piston acts to cancel the flow resistance to the mixture at the intake section, and when the mixture is drawn in, the pumping action takes away the engine output, causing the engine to run smoothly. The drawback was that it led to losses.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an engine intake system that eliminates the drawbacks mentioned above. In order to achieve this, a main intake port and an adjacent sub-intake port with a larger diameter than the main intake port are formed in the engine cylinder, and each port is provided with an intake valve for opening and closing. The intake valve at the intake port is controlled to delay the closing timing of the intake valve for the main intake port depending on the engine load and rotational conditions, and this delay control controls the air-fuel mixture introduced into the cylinder at the previous stage in the ignition order. It is designed to be introduced into the main intake port 1 in the cylinder at the rear stage which is connected to the auxiliary intake port 1 at the front stage.

In other words, the air-fuel mixture introduced into the cylinder whose ignition sequence has changed from the intake stroke to the compression stroke is introduced into the main intake port of the cylinder whose ignition stroke has changed from the intake stroke.

(Example) The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows a schematic plan view of an engine with four cylinders.

Each cylinder 1, 2, 3.4 has one exhaust port IE,
2E, 3E, 4E, the main intake ports IP, 2P, 3P, 4 are located at positions lateral to one side of the cylinder diameter line to promote swirl formation.
P, and a sub-intake port Is having a larger diameter than the main intake port at a position adjacent to the main intake port, 23.33.
43 are formed respectively.

Main intake pipes IP□, 2P1.3P□, 4P1 are connected between each main intake port and the Tsuyuel injection mixer 5.
However, between each sub-intake port and the twin injection mixer 5, there are sub-intake pipes Is1.2S1, 3S.

4S, are connected to each other.

Main intake port IP, 2P, 3P, in each cylinder
Main intake valve IP1.2P1.3 for opening and closing 4P and exhaust ports IE, 2E, 3E, and 4E.
P... 4P and exhaust valve 1. El, 2E1.3
E□ and 4E□ are provided respectively.

Each of these times, as shown in FIG. 2, is driven to open and close by an OHC mechanism composed of a camshaft 6 and a rocker arm 7 in a manner normally used in this type of engine.

On the other hand, sub-intake ports Is1.2S, 3S, 4S
1 also has an auxiliary intake valve 1 for opening and closing it. S2.2S
2' and 332°4S are provided, respectively.

In each of these cases, as shown in FIG.
It is designed to be opened and closed by a mechanism.

The camshaft 8 for this sub-intake valve is provided in a retard control mechanism DM shown in FIG.

The retard control mechanism DM includes a swing arm 15 that is swingably supported by a camshaft 6 for the main intake valve, and a swing arm 15 that is rotatably attached to the swing end of the swing arm 15. A first driven gear 17 that meshes with the first driving gear 16 fixed to the shaft 6, a rotating arm 19 having at its swing end a second driving gear 18 that meshes with the first driven gear 17; A sub-intake valve cam @8 to which the base end of the arm 19 is pivotally connected and is integrated with a second driven gear 20 that meshes with the second drive gear 18; The first
A rod member 21 is in contact with the end opposite to the end having the drive gear 18, and the rod member 21 is moved up and down in the figure. 8, and a transmission motor M, which is a driving member that rotates around the rotation axis 8.

The swinging arm 15 forms a part of a differential mechanism for retarding operation, which will be described later, and when the other end of a spring 22, which has one end hung on the cylinder head side, is applied, the swinging end is the first driven gear 17 and the second driving gear 1 on the rotating arm 19 side.
8 is given a rotational habit in a direction that always meshes with each other.

The direction and amount of rotation of the motor M are set and controlled by a control circuit (not shown), and the direction and amount of rotation are set according to the load condition of the engine based on the amount of depression of the accelerator pedal, etc. It looks like this.

Drive transmission from the electric motor M to the rod material 21 is carried out between the worm M1 attached to the shaft of the electric motor M and the rod material 2.
The worm wheel 2 has a female threaded portion formed on its inner circumferential surface to be screwed into the male threaded portion 21a integrated into the motor side end of the worm wheel 2.
1b.

Now, a case will be described in which when the worm M1 of the electric motor M rotates, the female threaded portion of the worm wheel 21b rotates and moves the rod material 21 up and down.

For example, when the rod 21 moves upward in FIG. 4, the end of the rotating arm 19 is pushed by the rod 21 as shown by the two-dot chain line in the figure, camshaft 8
Rotate counterclockwise using the fulcrum.

When this rotating arm 19 rotates, the swinging arm 15 resists the bias of the spring 22 via the second driving gear 18 and the first driven gear 17 of the rotating arm 19, and as shown in the figure, It swings counterclockwise about the camshaft 6 as a fulcrum.

At this time, the camshaft 6 for the main intake valve is
The drive gear 16 is on the fixed side of the differential mechanism, and the first driven gear 17 rolls on the first drive gear 16 during the swinging process of the swing arm 15.

Therefore, the first driven gear 1 rolling on the first driving gear 15
7, the meshing position with the first drive gear 15 is shifted from the position before rolling.

In this way, the first driven gear 1 with respect to the first driving gear 15
By shifting the engagement position of 7, for example, the time when the top edge of the auxiliary intake valve camshaft 8 faces the rocker arm can be changed from the time when the cam top edge of the main intake valve camshaft 6 faces the rocker arm. It is possible to delay the angle.

The above-mentioned sub-intake valve camshaft 8 receives air from the main intake valve camshaft 6 by rotating the second driven gear 20 via the first drive and driven gears 16 and 17 and the second drive gear 18. The auxiliary intake valve is driven to open and close by receiving the drive from the auxiliary intake cam. The retardation of this sub-intake valve will be described later.

Inside the aforementioned auxiliary intake pipe IS1.2S1.3S, 4S1, there is a shutter valve Is, 2S for opening and closing it.
3.3S,.

4S3 are provided respectively.

This shirt valve is driven to open and close by a vacuum motor attached to the engine E.
Particularly when the engine E rotates at low speed over the entire load range, the auxiliary intake pipe is closed to stop intake from the intermediate pipe.

As a result, during low-speed rotation, air is taken into the cylinder only from the main intake port 1, which has a smaller diameter than the auxiliary intake port, making it easier to generate high-speed swirl within the cylinder.

On the other hand, there is a connection between the main intake pipe and the auxiliary intake pipe between each cylinder, which is a means for connecting the auxiliary intake port at the front stage and the main intake port at the rear stage in the ignition order of each cylinder, which will be explained next. Ports 1.1.12.13.14 are arranged respectively.

For this communication port 11.1.2.13.14, the symbols 1, 2, and 3.4 shown in FIG. Assuming that the numbers are set as 1 → 3 → 4 → 2, the sub intake port 1S of the first cylinder 1 and the main intake port 3P of the third cylinder 3 are connected as shown in Fig. 3. , and the sub-intake port 3s of the 3rd cylinder 3 and the main intake port 4P of the 4th cylinder 4.
The sub-intake ports 1 to 48 of the fourth cylinder 4 are connected to the main intake port 2P of the second cylinder 2, respectively.

The operation of the above-mentioned configuration will be explained with reference to the diagram of FIG. 5 as follows.

In FIG. 5, the cam opening degree and air-fuel mixture intake in the medium and low load ranges indicate the state in the cylinder at the front stage in the ignition order.

In medium and low load ranges, the retard control mechanism DM (see Figure 4) allows the auxiliary intake valve's idle timing to be set to DT more than that of the main intake valve.
only to be delayed.

Due to this delay in closing the auxiliary intake valve, cylinders 1°2.3.
4, in the cylinder where the intake stroke shifts to the compression stroke, the air-fuel mixture is once sucked in, and this intake air-fuel mixture is blown back from within that cylinder through the auxiliary intake port during the compression stroke (region I in the figure). Become.

The blown-back air-fuel mixture is then transferred to the later cylinders in the ignition order, that is, the cylinders that are in the intake stroke, through communication ports H, 1, I2, .
1.3.14 (see Figure 2) and is introduced via the main intake port (area ■ in the figure).

The air-fuel mixture introduced into the cylinder during the intake stroke is promoted by the negative pressure during the intake stroke, and
The amount introduced is determined by the opening degree of the shutter valve in the auxiliary intake pipe that communicates with the preceding cylinder in the ignition order.

FIG. 6 shows this state by dividing the rotation state in each load range.

In FIG. 6, the auxiliary intake valve is shown as an S valve,
It has been clarified how the amount of retardation of the auxiliary intake valve (S valve) and the opening degree of the shatter valve in each load range affect the swirl efficiency in the cylinder and the filling efficiency of the air-fuel mixture.

In FIG. 6, intake air heating means the degree to which the air-fuel mixture receives heat, and pumping loss means the degree to which it affects the reduction in engine output.

In Fig. 6, "The lower the load range, the larger the retardation amount of the auxiliary intake valve (S valve) is set to increase the retardation amount of the auxiliary intake valve (S valve). Because the amount of air-fuel mixture blown back increases,
Combined with the configuration of the main intake port, the air-fuel mixture blown into the subsequent cylinder, that is, the cylinder that has entered the intake stroke, flows at an extremely high flow velocity.

Next, a modification of the communication port in the above-described embodiment will be explained with reference to the drawings from FIG. 7 onwards.

Note that the same members in FIGS. 7 through 12 as those shown in FIGS. 1 through 4 are given the same reference numerals.

Main intake pipes IP1, 2P1, 3P, 4P, shown in FIG.
and sub-intake pipe Is, , 2S, , 3S, , 4S
1, as shown in FIG. 9, the main intake pipes and the sub-intake pipes of each cylinder are arranged so as to be located on a virtual center line PC1SC parallel to the cylinder arrangement direction.

Therefore, the main intake pipe and auxiliary intake pipe are as shown in Figure 8.
When viewed from the front of the engine, each cylinder is formed to have the same shape.

On the other hand, in order to make the flow path shapes of the main intake pipe and the auxiliary intake pipe common to the corresponding intake pipes in each cylinder, the communication ports 1.10, 120, 130, and 140 are arranged as shown in FIG. In addition, the main intake pipe and the sub intake pipe are set in a shape that allows the main intake pipe and the sub intake pipe to be connected while bypassing adjacent intake pipes on the virtual center lines PC and SC.

According to this configuration of the communication port, the shape of the main intake pipe connected from the fuel injection mixer to the main intake port and the auxiliary intake pipe connected from the fuel injection mixer to the auxiliary intake port in each cylinder are determined. Since the shape of each cylinder is the same, the fuel distribution and swirl characteristics for each cylinder are uniform, and the assembly of the shatter valve is also possible because the auxiliary intake pipes are aligned at the same position. Compared to the case where the main intake pipe and the auxiliary intake pipe are mixed at the same position, that is, on the virtual center line, as in the embodiment shown in Figure 3, it is only necessary to assemble a single item, which simplifies the structure of the shirtta valve. be able to.

The use of such a communication port can be applied to a cylinder head having a size that allows a space for forming a so-called communication port, such as a cylinder block and a cylinder head that are integrally molded.

Further, FIGS. 10 to 12 show an example in which the communication port is provided outside the cylinder head of the engine instead of being provided inside the cylinder head of the engine.

In other words, the communication port is formed in the adapter 00 made of a shochu-heating member attached to the side of the cylinder head in a position continuous with the main and sub-intake ports, and its shape is similar to that of the seventh
The settings are the same as those shown in FIGS.

The adapter 100 is made of, for example, a heat-resistant synthetic resin and is provided with communication ports.

In this way, by providing the communication port outside the cylinder head of the engine via the adapter, a space for forming the communication port inside the cylinder head is not required, so that it is possible to suppress the increase in bulk of the cylinder head.

(Effect) Second, according to the present invention, the medium/low load range, in other words,
When lean combustion is required, the air-fuel mixture from the earlier cylinder can be introduced into the later cylinder in the ignition order, so the latter cylinder can generate a high swirl due to extremely strong blowing from the main intake port. This makes it possible to increase the combustion efficiency during lean combustion, and also allows the amount of blowback mixture to be variably set, making it possible to adjust the setting range of the mixture amount to obtain high EGR1 and high compression ratio. It is also possible to expand.

Moreover, as the load decreases, the amount of heat absorbed by the air-fuel mixture from the engine increases by increasing the amount of retardation of the sub-intake valve. The heat gain that affects the promotion of atomization of the air-fuel mixture is increased by reducing the amount of heat that becomes a loss, thereby allowing rapid and complete combustion to be performed and improving combustion efficiency.

In addition, since the pumping action in the intake stroke can be effectively used to create an ideal intake swirl according to each load condition, the same result can be obtained as suppressing the drop in engine output taken away by the pumping action. It will be done.

Furthermore, at high speeds and high loads, the main intake valve and auxiliary intake valve can increase the charging efficiency of air supply and achieve high output, resulting in high performance with high combustion efficiency and high output. We can provide a variety of engines.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the present invention, FIG. 2 is a view taken along the ■-■ arrow in FIG. 1, FIG. 3 is a view taken along the mm--m arrow in FIG. 1, and FIG. 8 is a schematic plan view showing the main parts of the embodiment of the present invention, FIG. 8 is a view taken along arrows ■-■ in FIG. 7, and FIG.
X-11X arrow view, FIG. 10 is a schematic plan view showing a further modified example of the main part of the embodiment of the present invention shown in FIG. 7, and FIG. Arrow view, 12th
The figure is a view taken along the arrow -■ in FIG. 10. 1, 2, 3, 4... cylinder, 1. P, 2P, 3
P, 4P...Main intake port, IP, 2P□, 3P,
, 4P1... Main intake valve, Is, 2S, 3S. 4S...Sub-intake port, Is2.2S2.3S2.4
S2...Sub-intake valve, is, , 2S3.3S3.4
S3...Shatta valve, E...Engine, 11, 12
, 1.3, 1.4... Communication port, DM... Retard control mechanism.

Claims (1)

[Claims] In an engine having multiple cylinders, a main intake port that communicates with a swirl forming blowout position in each cylinder, a main intake valve that opens and closes this port, and a main intake valve that opens and closes this port, and that communicates with the inside of the cylinder adjacent to the main intake port. A sub-intake port is formed larger than the above-mentioned main intake port, and a sub-intake port is provided to handle the engine load and
A sub-intake valve that can be opened and closed is controlled to retard the opening/closing timing of the main intake valve depending on the rotational state, and the sub-intake valve is provided in an intake passage communicating with the sub-intake port, and is provided in an intake passage communicating with the sub-intake port, and is provided in the engine load/rotation state. A shutter valve that opens and closes the intake passage according to , the closing timing of the auxiliary intake valve is delayed relative to that of the main intake valve, and due to this delay, the air-fuel mixture taken into the cylinder is transferred from the cylinder that has entered the compression stroke to the main intake air in the cylinder that has entered the intake stroke. An engine intake device characterized in that the air is introduced into the same cylinder through a port.