JPS587811B2 - Internal combustion engine gas injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas injection device for internal combustion engines, particularly for automobiles.

In conventional internal combustion engines for automobiles with a carburetor, the opening of the throttle valve is small and the amount of intake air is small during idle operation and light load operation, so the speed of the air-fuel mixture flowing into the cylinder from the intake manifold during the intake stroke is is low, and therefore the swirl of the air-fuel mixture inside the cylinder is also weak.

As a result, at the time of ignition, which normally occurs at the end of the compression stroke, the swirl of the air-fuel mixture remaining in the cylinder becomes weaker, resulting in lower ignition and combustibility, so in order to ensure stable engine operation, it is necessary to It is necessary to supply a mixture with a lower air-fuel ratio than during load operation, which not only increases fuel consumption but also reduces CO and CO in the exhaust gas due to incomplete combustion of the rich mixture.
There is a disadvantage that HC increases.

Recently, it has been proposed to burn a mixture that is sufficiently leaner than the stoichiometric mixture ratio, with the aim of reducing CO, HC, and even NOx in engine exhaust gas.
It has also been proposed to extract part of the exhaust gas from the engine exhaust system and mix it into the air-fuel mixture for combustion in order to reduce NOx in the exhaust gas, but in either case, the ignition of the air-fuel mixture Since the fuel efficiency and combustibility are lowered, drivability is lowered and fuel efficiency is also lowered.

Special Publication No. 47-24041 and Special Publication No. 47-43366
The prior art shown in the No. 1 sucks a rich mixture and air or a lean mixture into the cylinder through separate routes, prevents the two from mixing until the point of ignition, and immediately before ignition, the rich mixture is sucked into the cylinder around the spark plug. The air or lean mixture is guided to a location away from the spark plug, ignites the rich mixture, improves ignition combustibility, and achieves lean combustion with a large overall air-fuel ratio. However, according to such technology, there is a problem in that the device and control become complicated in order to always achieve good stratification and lead a rich air-fuel mixture to the vicinity of the spark plug regardless of the operating state.

The present invention is directed to an internal combustion engine proposed in view of the above, namely, to an intake manifold 11 forming a part of a main intake passage 10 in which a throttle valve (not shown) is interposed, as shown in FIG. 1 or FIG. A spark gap 18 of a spark plug 16 in a combustion chamber 14 with an intake port 12 connected thereto.
At the same time, an injection hole 20 for injecting gas in a set direction within the combustion chamber 14 as shown by an arrow Sub-intake passage 2
4 is provided, and gas is injected into the combustion chamber 14 from the injection hole 20 during the intake stroke, giving a strong swirl or turbulence to the air-fuel mixture supplied into the combustion chamber 14, and further scavenging air around the spark gap 18. In an internal combustion engine that improves ignitability and combustibility, expands the lean burn limit, and improves fuel efficiency and drivability, the main intake air between the venturi part of the carburetor and the above-mentioned throttle valve position at idle. A first port bored in the wall of the intake pipe of the passage and located substantially opposite to or downstream of the end face of the throttle valve when the throttle valve is idling, and becomes upstream from the opposite end face position of the throttle valve when the throttle valve opens. The auxiliary intake passage is connected to both ports of the second port bored in the intake pipe wall of the main intake passage, and the gas flow rate is controlled at least in a predetermined low-load operating range from the idling time of the engine and the operating range in the vicinity thereof. The gist of the present invention is a gas injection device characterized by being configured to increase the amount of gas.

In addition, in FIG. 1 and FIG. 2 above, 26 is a cylinder head, 28 is a cylinder block, 30 is a piston,
32 is the main intake valve, 34, 36 are rocker arms, 38, 4
0 is Rockshaft, 42 is camshaft, 44, 46
is a cam, 47 is an exhaust port, 48 is an exhaust valve, 50, 52
, 54 are adjustment screws, 56, 58, 60 are valve springs, 62, 64, 66 are retainers, 68 is a jet body, 10 is a jet piece, and the auxiliary intake valve 22 that opens and closes the auxiliary intake passage 24 is , 1st
As shown in the figure, it is driven by a rocker arm 34 that drives the main intake valve 32, and has substantially the same opening and closing timing as the main intake valve 32.

The main object of the present invention is to control the injection amount of the injection fluid from the injection hole (the amount of supply to the sub-intake passage), and to inject the gas in a predetermined low-load operating region from the operating region during and around idling. In addition to maximizing the jet effect from the injection holes in the predetermined low-load operating range mentioned above, it also reduces idling instability due to excessive injection, engine malfunction during extremely light-load operation, drivability, and fuel efficiency. An object of the present invention is to provide a gas injection device for an internal combustion engine for an automobile that prevents deterioration of the engine.

Further, in the present invention, the injection hole is communicated with the first port between the venturi part of the carburetor and the throttle valve position at idle, and some fuel is injected from the venturi part through the first port. When the air-fuel mixture is inhaled, it comes into contact with the auxiliary intake valve, the area near the injection hole, etc., and the fuel is vaporized, and the heat of vaporization cools the auxiliary intake valve, the area around the injection hole, etc., resulting in premature burnout or premature burnout due to overheating. This has the effect of preventing ignition.

Next, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 3 to 7.

FIG. 3 is a schematic layout diagram for explaining the overall structure of an embodiment of the present invention, in which the cylinder head portion of the internal combustion engine main body 72 is formed to have the same structure as that shown in FIGS. 1 and 2 above. and each element of the same part has the corresponding first
To describe each element with the same reference numerals as those in the figures and FIG. Furthermore, an air cleaner 78 is attached above the carburetor 76.

On the other hand, a catalytic converter (not shown) is interposed in the gathering part of the exhaust manifold 74, and exhaust gas purified by the catalytic converter is discharged into the atmosphere through an exhaust pipe 80.

A main intake passage 10 that communicates from the air cleaner 18 to the intake port 12 via the carburetor 76 and the intake manifold 11.
The detailed structure of the carburetor 16 portion will be explained with reference to FIGS. 4 to 1. The carburetor 16 is of a two-barrel type, and a main intake passage 10 is formed by a primary throttle bore 82 and a secondary throttle bore 84. There is.

By the way, the carburetor 76 has a two-part structure including an atsupa body 86 and a lower body 88.
A primary venturi 90 is formed in the bore 82 of the
A secondary venturi 92 is formed in the bore 84.

Further, a throttle shaft 94 is provided in the bore 82 of the lower body 88.
A throttle valve 96 that rotates around a throttle shaft 98 is installed in the bore 84, and a throttle valve 100 that rotates around a throttle shaft 98 is installed in the bore 84, and the throttle valve 96 is linked by operating an accelerator pedal (not shown). Alternatively, the throttle valve 100 is opened and operated via a cable, and mainly controls the intake air amount and mixture concentration from idle to medium load. It opens when the load exceeds the load, and closes in the operating range from idle to medium load.

By the way, as is clear from FIG. 1, the sub intake passage 24 formed in the cylinder head 26 is connected to the intake manifold 11.
It communicates between the joint surfaces of the lower body 88 and the intake manifold 11 through a sub-intake passage 24 formed integrally with the lower body 88, and the sub-intake passage 24 includes a hole 102 that penetrates from the upper surface to the lower surface of the lower body 88; Hole 1 located close to bore 82 via groove 104 formed on the upper surface of lower body 88
06 and 108.

Further, when the throttle valve 96 on the intake pipe wall on the bore 82 side of the lower body 88 is located at the idle opening shown in the drawing, it is substantially opposed to the end surface 110 of the throttle valve 96, and when the throttle valve 96 opens. A port 112 is bored at a set position upstream from the position of the opposing end face 110 of the throttle valve 96, and a port 114 is bored at a position always sufficiently upstream from the position of the opposing end face 110 of the throttle valve 96. Port 112 communicates with hole 106 and port 114 communicates with hole 108 .

According to the above configuration, from the air cleaner 78 to the main intake passage 10
Most of the air taken into the engine is mixed with fuel at a predetermined air-fuel ratio in the carburetor 16, and then taken into the combustion chamber 14 through the intake port 12, and a portion is mixed into the combustion chamber 14 through the ports 112 and 114.
are guided to the grooves 104 through the holes 106 and 108, and further from the grooves 104 to the injection holes 20 via the holes 102 and the auxiliary intake passage 24, and from the injection holes 20 to the combustion chamber 1.
It is injected within 4 days.

The amount of injection and the strength of the jet flow from the injection hole 20 are determined by the amount of restriction determined by the resistance in the passage from the ports 112 and 114 to the injection hole 20 via the auxiliary intake passage 24;
Opening timing and period of sub-intake valve 22 and throttle valve 96
It changes depending on the opening degree, vehicle speed, etc.

In addition, especially at low throttle opening, port 112
In response to changes in the hole diameter and position of the holes 114 and 114, the injection amount characteristics with respect to the throttle opening change greatly.

In this embodiment, as shown in FIG. 5, the port 112 and the port 114 are
The opening positions of the openings have angles of C=55° and D=250 on a plane centered on a point on the center line of the bore 82, respectively.

Further, as shown in FIG. 6, the port 112 is located below the height of the center line of the throttle shaft 94 by E=2.5 to 3.1 mm, and as shown in FIG. The port 114 is located F=5.0 mm higher than the position shown in FIG.

Therefore, during idling with a small throttle opening or when operating with a very light load, the opposite end surface 11 of the throttle valve 96
0 is located above or at approximately the same position as the port 112, and the negative pressure generated in the port 112 increases due to the throttling action of the throttle valve 96, and this large negative pressure causes the boat 11 to
A part of the intake air flowing into the groove 104 from 4 through the hole 108 returns to the main intake passage 10 through the hole 106 and the port 112.
taken back inside.

Therefore, even though high negative pressure is generated in the combustion chamber 14 during the intake stroke, the flow rate of air injected into the combustion chamber 14 from the injection hole 20 can be suppressed within a range that does not cause combustion instability. .

On the other hand, when the throttle valve 96 is opened slightly from the above state and the opposing end surface 110 comes below the port 112, the negative pressure generated at the port 112 becomes a low negative pressure, and the port 11
4, the pressure difference between the pressure inside the main intake passage 10 and the vicinity of the main intake passage 10 becomes smaller.
Most of the intake air flowing into the groove 104 from the port 114 is guided to the injection hole 20 via the auxiliary intake passage 24, and when the throttle valve 96 is opened, the negative pressure generated in the port 112 is generated in the port 114. It becomes almost equal to the negative pressure that occurs, and approaches atmospheric pressure.

Therefore, due to the high negative pressure generated in the combustion chamber 14 during the intake stroke, a large amount of intake air is injected into the combustion chamber 14 from the injection hole 20, and as a result, the intake air-fuel mixture in the combustion chamber 14 is caused by the jet flow of the intake air. Generates strong swirl or turbulence.

In this embodiment, the amount of sub-intake air supplied from the injection holes 30 is set to approximately 30 to 50% of the total intake air amount at idle, and in a predetermined low-load operating region, the ratio of the amount of sub-intake air is greater than that at idle. To increase.

By the way, in the conventional device, the negative pressure of the port 112 as described above was not applied to the intake passage to the auxiliary intake passage 24, and intake was only taken from a place where the pressure was always close to atmospheric pressure. If the injection amount is optimal in the operating range, the intake amount from the auxiliary intake passage 24 will be large during idling or extremely light load operation, and the spark gap of the ignition plug 16 and the area around the spark plug 18 will be supercooled, reducing the ignitability of the air-fuel mixture. This has the drawback of causing a misfire and making idling and extremely light load operation unstable.

In the above embodiment, a high negative pressure is generated in the port 112 during idling and under very light load, and a portion of the air that has flowed into the groove 104 returns to the main intake passage 10, so that the injection from the injection hole 20 is prevented. This reduces the amount of power generated, eliminates instability during idling and extremely light load operation, reduces engine vibration, and improves drivability and fuel efficiency.

In addition, in the above embodiment, the port 112 is C=55°
On the other hand, the port 114 is located close to the throttle shaft 94 at an angle of D=25°, which is far from the throttle shaft 96. In order to prevent the influence of the intake manifold negative pressure, which is a high negative pressure generated on the downstream side, from being affected as much as possible on the port 114, the effect of the above-mentioned manifold negative pressure is strongly applied to the port 112 at the idle opening, so that the throttle valve This is provided with the intention of gradually reducing the effect as the valve 96 opens and moves.

Although not shown, in a device in which a choke valve is installed upstream of the venturi 90, a larger amount of fuel is injected from a main nozzle (not shown) that opens into the venturi 90 when the choke valve is closed.

Therefore, if too much fuel enters from the port 114, the spark plug 16 injected from the injection hole 20 will fog up, causing a starting failure, but in the above embodiment, in order to prevent the fuel from entering too much, F= The port 114 is opened 5.0 mm above the throttle valve 96 as much as possible.

In addition, port 114 in the above actual case is Venturi 9.
0 and the upper surface of the throttle valve 96, the air-fuel mixture containing some fuel is sucked in from the port 114 during medium and high loads, and the air-fuel mixture is transferred to the sub-intake valve 22,
The fuel is vaporized by contacting the jet piece 70 and the like, and the heat of vaporization causes the sub-intake valve 22 and the jet piece 70 to
etc., thereby preventing burnout or premature ignition due to overheating.

FIG. 8 shows a modification of the above embodiment, in which an adjustment screw 116 is provided to adjust the flow area of the port 114 in the above embodiment, and by adjusting the screw 116, the sub-intake flow rate can be easily adjusted to an optimum amount. It is adjusted so that

Note that in the above modification, the flow area of the port 114 is adjusted, but even if an adjustment screw is provided in the port 112 and the flow area of the port 112 is adjusted, the sub-intake amount can be adjusted in the same way.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an automobile internal combustion engine provided for the present invention;
FIG. 2 is a bottom view of the combustion chamber of the automobile internal combustion engine in FIG. An enlarged sectional view of the main part of the embodiment, FIG. 5 is a view taken along the J-J arrow in FIG. 4,
6 is a sectional view taken along the line AA in FIG. 5, FIG. 1 is a sectional view taken along the line BB in FIG. 10: Main intake passage, 11: Intake manifold, 12: Intake port, 14: Combustion chamber, 16 Two spark plugs, 18: Spark gap, 20: Injection hole, 22: Sub-intake valve, 24:
Sub-intake passage, 26: cylinder head, 32: main intake valve,
12: Internal combustion engine body, 16: Carburetor, 18: Air cleaner, 82: Primary throttle bore, 84: Secondary throttle bore, 86: Atsupa body, 88: Lower body, 90: Primary venturi, 92: Second 96, 100: Throttle valve, 102, 106, 108
: hole, 104: groove, 110: end face, 112: 114: port, 116: adjustment screw.

Claims (1)

[Claims] 1. The spark gap of the ignition plug faces into the combustion chamber which has an intake port connected to the main intake passage in which the throttle valve of the carburetor is installed, and the spark gap of the ignition plug is located near the spark gap in the combustion chamber. In an internal combustion engine that is provided with an injection hole that injects gas in a set direction and a sub-intake passage that is connected to the injection hole via a sub-intake valve, the venturi part of the carburetor and the above-mentioned throttle valve position at idle and a first port bored in the intake pipe wall of the main intake passage between the main intake passage and the first port located substantially opposite to or downstream of the end face of the throttle valve at idle, and when the throttle valve opens and moves. The auxiliary intake passage is connected to both ports of a second port bored in the intake pipe wall of the main intake passage upstream from the opposing end face position, and the auxiliary intake passage is connected to both ports of a second port bored in the intake pipe wall of the main intake passage, which is located upstream from the opposite end face position, and is connected to a predetermined lower temperature than the operating range at least when the engine is idling and in the vicinity thereof. A gas injection device for an internal combustion engine, characterized in that the gas injection device is configured to increase the gas flow rate in a load operating region. 2. A gas injection device for an internal combustion engine, in which at least one of the first port and the second port is provided with an adjustment screw for adjusting the flow rate.