JPH03928A - Intake system for internal combustion engine - Google Patents

Abstract

PURPOSE:To surely perform combustion of mixture and improve fuel consumption by forming a feed nozzle to feed exhaust gas (or air) in the proximity of an intake valve, and blowing out exhaust gas from the feed nozzle synchronizing with the section stroke of an internal combustion engine. CONSTITUTION:When an EGR device is used as an exhaust gas for pumping loss feed device, a control valve 20 is provided between on the way of an exhaust gas recovering pipe 23 connecting its upper stream end to a recovery port 13a formed on an exhaust manifold 13, and the lower stream end of the recovering pipe 23 is connected to the introducing port 31 of a rotary valve 30 as a feed timing control means to inject exhaust gas synchronizing with the suction stroke of an engine 1. The control valve 20 is controlled for its opening degree with negative suction pressure through a control valve 38 controlled according to the load and the rotating speed of the engine. A feed nozzle 37a arranged on the part facing an intake valve 9 in an intake passage 7 is connected to the feed port of the rotary valve 30 through piping.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake system for an internal combustion engine.
The present invention relates to an intake device that can improve fuel consumption rate (hereinafter referred to as fuel efficiency).

(Prior Art) The operation of a 4-stroke engine consists of four strokes: an intake stroke, a compression stroke, a combustion-expansion stroke, and an exhaust stroke.The intake stroke opens the intake valve and moves the piston downward to create a negative load inside the combustion chamber. This is a stroke in which pressure is generated and the fuel mixture is sucked into the combustion chamber.In this intake stroke, there is a so-called pumping loss, which is the pumping loss when sucking the fuel mixture into the combustion chamber by the downward movement of the piston. There is a problem that this occurs and fuel consumption deteriorates.

This pumping loss increases during low load operation with the throttle valve in a substantially closed state. In order to reduce such pumping loss as much as possible and improve fuel efficiency, an intake device that supplies a portion of the exhaust gas into the intake manifold has conventionally been added to the engine. This intake system has one end of an exhaust gas recovery pipe connected to the exhaust manifold, and the other end connected to a gathering part of the intake manifold, and the recovery pipe is equipped with a diaphragm control valve that opens and closes depending on the internal pressure of the intake manifold. It is configured with the following settings. According to this intake device, the internal pressure of the intake manifold can be brought to a substantially atmospheric pressure state by supplying exhaust gas into the intake manifold and mixing it with the fuel mixture, so that the pumping loss during the intake stroke can be reduced.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned conventional intake system, the pumping loss can be reduced by increasing the amount of exhaust gas supplied. However, if the amount of exhaust gas exceeds, for example, 20% of the fuel mixture, the fuel mixture Good combustion cannot be obtained, leading to poor flame propagation and misfires. Therefore, there is a problem that there is a limit to increasing the amount of exhaust gas supplied, and as a result, there is a limit to reducing the pumping loss as well.

Here, in order to increase the amount of exhaust gas supplied without causing poor flame propagation or misfire, the exhaust gas and fuel mixture are supplied into the combustion chamber in a layered manner, and the area around the ignition part, that is, the spark plug, is It is conceivable to make only the fuel mixture unevenly distributed. However, the above-mentioned conventional intake system has a structure in which exhaust gas is inhaled by the negative pressure of the intake manifold.On the other hand, in the case of a multi-cylinder engine, since one of the cylinders is in the intake stroke, the above-mentioned intake Generally, the internal pressure of the manifold is maintained at negative pressure at all times. Therefore, in the conventional device, exhaust gas continuously flows into the intake manifold, and for example, in a four-cylinder engine, approximately 374 of the total amount of exhaust gas supplied to the intake manifold flows into the intake manifold before the intake stroke. There has already been an influx, and as a result,
Even if the exhaust gas supply port is provided near the intake valve, the exhaust gas is drawn in from the entire circumference of the intake valve at the beginning of the intake stroke and diffuses within the combustion chamber. Therefore, it is difficult to supply the exhaust gas in a stratified manner with conventional devices.

The present invention has been made in view of the above-mentioned conventional situation, and an object of the present invention is to provide an intake device for an internal combustion engine that can increase the amount of exhaust gas supplied while reliably avoiding poor flame propagation and misfire, and can further reduce pumping loss. It is an object.

[Means for solving problems]

Therefore, the present invention forms a supply nozzle for supplying exhaust gas or air near the intake valve in the intake passage communicating with the combustion chamber, and jets out the exhaust gas or air from the supply nozzle in synchronization with the intake stroke. This is an intake system for an internal combustion engine, characterized in that it is provided with a supply timing control means for controlling the supply timing.

The supply timing control means can be realized, for example, by connecting a rotary timing valve to the supply nozzle and synchronizing the opening operation of the valve with the opening operation of the intake valve.

Furthermore, when the exhaust gas and air are injected into the combustion chamber, it is desirable to give them directionality so that they swirl along the inner circumferential wall of the cylinder or along the bottom wall of the intake passage. The stratified supply of the fuel mixture and fuel mixture can be more reliably performed.

Further, in the present invention, either exhaust gas or air may be supplied, but from the viewpoint of reducing pumping loss and ensuring an air/fuel ratio A/F that allows the three-way catalyst to operate efficiently. If it stands, it is desirable to supply exhaust gas.

[Effect]

According to the intake system for an internal combustion engine according to the present invention, the exhaust gas or air is ejected from the vicinity of the intake valve in synchronization with the intake stroke, so that the exhaust gas or air is ejected in a concentrated manner only during the intake stroke. Therefore, the exhaust gas or air and the fuel mixture can be supplied into the combustion chamber in a layered manner, and only the fuel mixture can be unevenly distributed in the ignition part. As a result, the amount of exhaust gas supplied can be increased while the fuel mixture is reliably combusted, bombing loss can be reduced without problems such as poor flame propagation and misfires, and fuel efficiency can be improved.

(Example〕 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Figures 1 to 4 are diagrams for explaining an intake system for a four-stroke engine according to an embodiment of the present invention.In this embodiment, an exhaust gas recirculation system (EGR) is used to reduce An example will be explained in which the pump is also used as an exhaust gas supply device for pumping loss.

In the figure, 1 is a four-cycle engine that uses gas such as propane as fuel, and this has a cylinder head 3 placed on the top surface of a cylinder block 2, and a head cover (not shown) that covers the top surface of the cylinder block 2. It has a structure covered with A piston 4 is disposed in the cylinder block 2 so as to be reciprocatable, and a combustion chamber 5 is formed by the piston 4 and a recess formed in the base of the cylinder head 3. Note that 5a is a spark plug. The cylinder head 3 is formed with an exhaust passage 6 and an intake passage 7 that communicate with the combustion chamber 5, respectively, and each passage 6.7 is provided with an exhaust valve 8 and an intake valve 9 for opening and closing the passage. There is. Each valve 8.9 also has a coil spring 1.
0 in the closing direction. Further, a camshaft 12 is disposed at the upper end of each valve 8.9 via a cylindrical valve lifter 11, and the camshaft 12 is disposed at the upper end of each valve 8.9.
Although not shown, 2 is connected to the crankshaft via a timing belt.

One end of an exhaust manifold 13 is connected to the exhaust passage 6, and the other end of the exhaust manifold 13 is connected to a muffler via a three-way catalytic converter (not shown). Further, one end of an intake manifold 14 is connected to the intake passage 7, and a capretor 15 is connected to the other end of the intake manifold 14.

This carburetor 15 includes a venturi section 15a to which a fuel supply pipe 15c is connected, and a throttle valve 15b disposed downstream of the venturi section 15a, and an air cleaner 16 is connected to the upstream end of the carburetor 15. .

Reference numeral 18 designates the intake device of this embodiment, which includes a control valve 20 interposed in the middle of the exhaust gas recovery vibe 23.
and a rotary valve 30 as a supply timing control means for injecting exhaust gas in synchronization with the intake stroke of the engine 1.
It is composed of. The control valve 20 has a recovery passage 20b and a supply passage 20 in a valve body 20a.
c is in communication with each other, an on-off valve 21 is disposed in the recovery passage 20b, and a diaphragm 22 is connected to the on-off valve 21. In addition, the exhaust gas recovery vibe 23
The upstream end of the exhaust manifold 13 is connected to the recovery port 13a formed in the exhaust manifold 13, and the lower end thereof is connected to the inlet 31 of the rotary valve 30. Further, one end of a communication pipe 24 is connected to the diaphragm 22, and the other end of the communication pipe 24 is connected to a communication port 14a formed in the intake manifold 14. Further, a control valve 38 is interposed in the middle of this communication pipe 24. This control valve 38 is for opening and closing the on-off valve 21 according to the engine load and engine speed. For example, when the engine load is low, the on-off valve 21 is throttled to reduce the exhaust gas flow rate and stabilize combustion. Plan. Also, when the load is constant, the higher the engine speed, the more the opening/closing valve 2
1 to keep the exhaust gas flow rate constant.

The rotary valve 30 is constructed by inserting a rotary valve 30b into a valve body 30a fixed on the intake manifold 14. A supply port 32 is formed in the valve body 30a so as to be perpendicular to the introduction port 31,
This introduction port 31. The supply port 32 is communicated or closed by rotation of the rotary valve 30b. Further, a sprocket 33 is fixed to the rotating shaft of the rotary valve 30b, and this sprocket 33 is attached to the camshaft 1.
Timing belt 3 is attached to sprocket 34 fixed to sprocket 2.
5. When the camshaft 12 presses the intake valve 9 to open the rotary valve 30b, the inlet port 31 and the supply port 32 communicate with each other in synchronization with this.

One end of an exhaust gas supply vibrator 37 is connected to the supply port 32 of the rotary valve 30, and the other end of this is connected to a supply nozzle 37a.

This supply nozzle 37a is arranged in a portion of the intake passage 7 of the cylinder head 3 facing the intake valve 9, and the tip of the nozzle 37a is directed in the tangential direction of the inner wall of the combustion chamber 5 (the fourth (see figure).

This allows the intake device 1 to eject exhaust gas from the supply nozzle 37a in synchronization with the intake stroke of the engine 1.
8 are made up.

Next, the effects of this embodiment will be explained.

The operation of the intake system 18 of the four-cycle engine 1 of this embodiment will be explained with reference to FIGS. 2 to 4. FIG.

In the intake stroke of the engine 1, the camshaft 12 opens the intake valve 9 in synchronization with the downward movement of the piston 4, and the rotary valve 30b of the low-return valve 30 communicates the inlet 31 and the supply port 32, thereby causing combustion. A fuel mixture F and exhaust gas G are drawn into the chamber 5 . In this case, the exhaust gas G ejected from the supply nozzle 37a is controlled by the opening of the on-off valve 21 by the control valve 38 and the combustion chamber 5.
The amount corresponding to the negative pressure inside the combustion chamber 5 is supplied.
It swirls along the inner wall of the combustion chamber 5, and is unevenly distributed on the inner circumferential wall of the combustion chamber 5. On the other hand, the fuel mixture F is supplied in an amount corresponding to the opening degree of the throttle valve 15b, and
The exhaust gas G and the fuel mixture F are unevenly distributed in the center of the combustion chamber 5, so that the exhaust gas G and the fuel mixture F are supplied in two layers: an outer layer and a center layer.

As described above, according to this embodiment, the exhaust gas G is concentrated in synchronization with the single stroke of the engine 10) and is ejected so as to swirl along the inner circumferential wall of the combustion chamber 5, so that the exhaust gas G and the fuel are The air-fuel mixture F can be unevenly distributed in a layered manner, and as a result, even if a large amount of exhaust gas G is supplied, almost no effect on ignition and flame propagation can be avoided. As a result, pump loss can be reduced by the amount that the supply amount of exhaust gas G can be increased, and fuel efficiency can be improved. Moreover, in this embodiment, since the exhaust gas is recirculated, the combustion temperature is lowered and NO8 can be reduced. Furthermore, since the exhaust gas is supplied, the A/F can be set within the operating range (stoichiometric air-fuel ratio) of the three-way catalyst, allowing the three-way catalyst to operate effectively.

In addition, although the above embodiment has been explained by taking as an example the case where exhaust gas is supplied during the intake stroke, the present invention may also supply air, and even in this case, it is possible to supply the exhaust gas in a layered manner by synchronizing with the intake stroke. The same effect as in the above embodiment can be obtained.

Further, in the above embodiment, the rotary valve 30b starts opening at the same time as the intake valve 9 starts opening, but the opening timing does not necessarily have to be the same.
The key is to adjust the timing so that the exhaust gas can be ejected in a concentrated manner near the intake valve during any period during the intake stroke.6 Figures 5 and 6 show a modification of the above embodiment. Inside, the same reference numerals as in FIG. 1 indicate the same or corresponding parts. In this modification, the bottom wall 1 of the intake manifold 14
4b is formed with an exhaust gas supply passage 40, the upstream end of the passage 40 communicates with the supply port 32 of the low-resolution valve 30, the downstream end communicates with a supply nozzle 41, and the supply nozzle 41 is connected to a slit along the bottom wall of the intake passage 7. This is an example in which it is formed into a shape.

In this modification, exhaust gas is sucked into the combustion chamber 5 along the bottom wall surface of the intake passage 7 in synchronization with the intake stroke of the engine 1, and is unevenly distributed on the right inner wall portion of the combustion chamber 5 in FIG. It happens. In this manner, also in this modification, the exhaust gas and the fuel mixture can be supplied in a layered manner, and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the intake system for an internal combustion engine according to the present invention, the supply nozzle is formed near the intake valve, and supply timing control is performed to eject exhaust gas or air from the supply nozzle in synchronization with the intake stroke. Since the means is provided, exhaust gas or air and fuel mixture can be supplied into the combustion chamber in a stratified manner, and the amount of exhaust gas etc. to be supplied can be increased while ensuring combustion of the fuel mixture. This has the effect of reducing bombing loss and improving fuel efficiency.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining an intake system for a four-stroke engine according to an embodiment of the present invention.
The figure is a schematic diagram of the configuration, Figure 2 is a schematic diagram of the intake stroke, and Figure 3 is a schematic diagram of the intake of exhaust gas.
Fig. 4 is a schematic diagram of the inside of the combustion chamber, Fig. 5 is a schematic configuration diagram showing a modification of the above embodiment, and Fig. 6 is a vr-vr diagram of Fig. 5.
FIG. In the figure, 1 is a 4-cycle engine (internal combustion engine), 5 is
1 is a combustion chamber, 7 is an intake passage, 9 is an intake valve, 18 is an intake device, 30 is a rotary valve (supply timing control means), 3
7a and 41 are supply nozzles, and G is exhaust gas.

Claims (1)

[Claims] (1) Near the intake valve in the intake passage communicating with the combustion chamber,
An internal combustion engine characterized by comprising a supply nozzle for supplying exhaust gas or air, and supply timing control means for jetting out the exhaust gas or air from the supply nozzle in synchronization with the intake stroke of the internal combustion engine. Engine intake system.