JPS581254B2 - 4 Cycle Ninen Kikan - Google Patents

Description

[Detailed description of the invention] This invention ensures combustion of the lean mixture by making the air-fuel mixture of a four-cycle internal combustion engine a lean air-fuel mixture as a whole, but partially rich air-fuel mixture near the spark plug. This relates to a four-stroke internal combustion engine.

In particular, this invention provides a port for introducing air near the bottom dead center of the piston in a four-stroke reciprocating internal combustion engine, and air is introduced into the cylinder from this port to make the air-fuel mixture a non-homogeneous air-fuel mixture, and a rich mixture. This makes it possible to operate the internal combustion engine with an extremely lean mixture as a whole, and to eliminate CO, HC, and the most difficult-to-treat mixtures. In addition to being an effective means of pollution prevention by minimizing the amount of NOx emitted, it also has many features such as improving engine performance and making the device relatively simple.

Conventional four-stroke internal combustion engines are designed to keep the mixture of fuel and air as homogeneous as possible.

Further, the air to fuel ratio A/F has been used in the range of 10:1 to 16:1 depending on the required use of the internal combustion engine.

For example, 10-13:1 during acceleration, 15-13:1 during constant speed.
16:1, and 11 to 14:1 at high speeds and high outputs.

FIG. 2 shows a relationship curve between exhaust pollution components and air-fuel ratio A/F of a general internal combustion engine.

The curve shown by the solid line shows an example when the combustion chamber temperature is high,
The dotted curve shows the low case.

A common condition for improving the performance of an internal combustion engine is to increase the gas temperature in the combustion chamber even at the same air-fuel ratio.

Therefore, CO and HC gases burn well and are not included in the exhaust gas much, but NOx significantly increases.

Conversely, when the combustion gas temperature is low, the amount of NOx generated is small, but HC increases.

As shown in Figure 2, when the air-fuel ratio is extremely low, that is, when the mixture is rich, NOx can be reduced, but CO
, HC becomes an extremely large value.

Conversely, when the air-fuel ratio is large, that is, the mixture is lean, the N
Not only Ox, but also CO and HC should become small values, which should be preferable, but in this case, since the calorific value per volume of the mixture is small, not only will the engine output and rotational speed become low, There are disadvantages in that phenomena such as misfires occur and the HC value increases, further rendering the system inoperable.

This invention attempts to eliminate the above-mentioned drawbacks by burning an extremely lean mixture of 19 to 21:1 as a whole.

As shown in FIG. 1, a first chamber 1 serving as a rich mixture chamber is disposed above the cylinder 2, and is provided with an ignition plug 3 as an ignition means and an intake hole 4 for sucking in a rich mixture. The intake hole 4 is provided with an intake valve 5 to open and close the intake hole 4.

The first chamber 1 is also provided with a nozzle hole 6 to conduct the first chamber 1 into the cylinder 2.

Therefore, the intake valve 5 opens during the intake stroke, and the piston 7
When the cylinder 2 descends, the carburetor 8 attached to the top of the cylinder 2
The rich mixture is sucked into the first chamber 1 through the intake hole 4 .

After the first chamber 1 is filled with the rich mixture, the mixture is sucked into the cylinder 2 through the injection holes 6.

In this invention, a port 9 is provided in the T-direction portion of the cylinder 2, and when the piston 7 has passed the middle of its intake stroke as a left-input device, the secondary air pre-pressurized in the crank chamber 10 is passed through the boat 9 into the cylinder. 2.

FIG. 4 shows a case in which secondary air is precompressed by a blower 19 as a left-inlet device.

As mentioned above, the first chamber 1 is filled through the intake hole 4, and the cylinder 2 is filled with air.
The air-fuel mixture sucked into the cylinder is a rich air-fuel mixture, but the pressure is low, and the secondary air that flows in from port 9 at the bottom of the cylinder is pre-pressurized, so this secondary air can absorb the rich air-fuel mixture. The primary air-fuel mixture is pushed up, and a non-homogeneous or stratified air-fuel mixture is formed inside the cylinder 2.

The concentration of the rich mixture in the first chamber 1 and the concentration of the stratified mixture in the cylinder 2 are determined by the concentration of the mixture produced in the carburetor 8, the resistance of the intake system, and the opening of the port 9 at the bottom of the cylinder. It is determined by the hole time, hole area, preload force, etc.

The secondary air flowing in from port 9 is heated or cooled, the exhaust gas is mixed with it and recirculated, and water, alcohol (methanol), and other combustion suppressants and combustion promoters are added to create an air-fuel mixture. can flow into port 9 to improve engine performance and prevent pollution.

By forming a stratified mixture as described above, it is possible to reliably ignite the rich mixture around the ignition plug 3 first.

Then, using the power of the flame, the lean and rich aiki in the lower part of cylinder 2 is completely burned one after another to prevent misfires.

In the suction stroke of this invention, as shown in FIG. 1, when the histone 7 passes the center of the stroke, the port 9 is opened at the upper helix of the piston 7, and the piston 7 continues to descend, passing the bottom dead center. The secondary air sucked and compressed into the crank chamber 10 is pumped into the crank chamber 10 by the pump action performed by the vertical movement of the piston until the open port 9 is closed again. It flows forcefully into the cylinder 2 through the cylinder 2.

In this case, if the shape of the port 9 is inclined in the tangential direction with respect to the wall of the cylinder 2, the inflowing secondary air will flow into the cylinder 2 along the cylinder wall.
It directly licks the surface of the piston 7 inside and rises while making a turning movement.

Therefore, the upward flow is attenuated, which not only helps to form a stratified mixture with the rich mixture from above, but also facilitates complete combustion of the lean mixture portion during combustion.

Similarly, if the nozzle hole 6 is formed in a tangential direction to the wall of the cylinder 2, the rich air-fuel mixture will flow downward while swirling inside the cylinder 2, further improving the same effect as above.

The above-mentioned rich primary mixture has a pressure somewhat lower than atmospheric pressure, but the secondary air has a pressure considerably higher than atmospheric pressure, so the secondary air pushes up from the bottom upwards while mixing with the primary mixture. , a so-called perfect stratified mixture is formed.

When the piston 7 starts moving upward and closes the port,
Since the stratified mixture in cylinder 2 has a prepressure slightly higher than atmospheric pressure, this is a better condition for improving output than in a conventional four-stroke engine.

As the piston 7 moves upward, the air-fuel mixture in the first chamber 1 and the cylinder 2 is compressed into a stratified air-fuel mixture.

As the area around the ignition plug 3 is surrounded by a rich air-fuel mixture as mentioned above, combustion is fast and the temperature of the combustion gas is high, so the inside of the first chamber 1 becomes extremely high temperature and pressure, and unburned components due to lack of air are It passes through the nozzle hole 6 and is ejected into the cylinder 2 together with the flame.

Since the first chamber 1 is a rich mixture, a large amount of CO and HC are generated, but due to the lack of oxygen even at high temperatures, the generation of NOx is suppressed and becomes small.

Subsequently, the unburned part is injected into cylinder 2 at high temperature, but since the mixture inside cylinder 2 becomes leaner as it moves toward the lower part of the cylinder, CO and H are supplied with enough oxygen.
C is completely combusted and eliminated as shown in FIG.

As for NOx, even if there is sufficient oxygen supplementation in cylinder 2, the ambient gas temperature is not high enough to generate NOx, so NOx cannot be generated, and the value remains very small. .

In this way, the combustion of the mixture is transferred from the first chamber 1 to the cylinder 2, but unlike the conventional homogeneous mixture combustion, the combustion method uses a non-homogeneous, stratified mixture, resulting in a very A lean mixture can be completely combusted.

During the combustion period, the piston 7 receives power from the combustion gas as an output source and descends to perform the expansion stroke, but shortly before the upper helix of the piston 7 opens the port 9 provided at the bottom of the cylinder 2 again. First, it is necessary to open the exhaust valve 11 located at the top of the cylinder to lower the gas pressure inside the cylinder 2 to near atmospheric pressure.

When the exhaust valve 11 opens, the gas in the cylinder 2 is discharged into the exhaust pipe with great force.

Because the air column inside the exhaust pipe is extremely high-speed, Cadenashi (K
Due to the adenacy effect, the gas pressure in the cylinder 2 is (possibly) lowered to below atmospheric pressure.

When the piston 7 continues to descend 5 degrees and opens the port 9 provided in the lower part of the cylinder 2, the secondary air pre-pressurized by the up and down movement of the piston 7 in the crank chamber 10 returns to the suction stroke. Similarly, the gas flows into the cylinder 2 through port 9.

This secondary air pushes up the residual exhaust gas in the upper layer toward the exhaust valve 11 at the top of the cylinder and exhausts it, so that the inside of the cylinder is almost replaced with fresh air.

Due to changes in engine load, rotational speed, intake and exhaust system, etc.
There is a possibility that the gas in the cylinder 2 flows back into the port 9 when the port is opened as described above, but the countermeasure for this is exactly the same as in the case of a conventional two-cycle engine, and this countermeasure is already known.

The secondary air from port 9 flows into cylinder 2 until piston 7 passes through the dead center and moves upward again, closing port 9.
The exhaust valve 11 is the same as in the case of a normal four-stroke engine, although the combustion gas is pushed up from below.
After opening the port, which is closed after passing the top dead center, the exhaust gas is expelled through the exhaust stroke due to the upward movement of the piston 7, which is exactly the same as the exhaust stroke of a normal four-stroke engine. .

The difference is that in conventional engines, the upper surface of the piston 7 is in direct contact with the hot gas, whereas in this invention, cold secondary air is inserted between them to push out the exhaust gas. That's true.

When the piston 7 approaches the dead center, there is no exhaust air in the upper part of the cylinder 2 and in the exhaust hole 12, but rather a small amount of air is sent out to the exhaust pipe.

During the exhaust period, cold secondary air flowing from port 9 along the upper surface of piston 7 reduces the heat load on piston 7 and has a positive effect such as cooling the lubricating oil in cylinder 2. Not only that, but secondary air is sent into the exhaust pipe 12 at the end of the exhaust stroke, so there is no need to install a special air pump to prevent exhaust pollution, and in the unlikely event that the primary air-fuel mixture Even if the overall air-fuel mixture becomes too rich and exceeds the stoichiometric mixture ratio, it is possible to make it function as a type of thermal reactor by heating a part of the exhaust pipe and keeping it warm. It is possible to burn CO and HC gases in the exhaust pipe to eliminate exhaust pollutants.

When the piston 7 passes the top dead center following the exhaust stroke, the piston 7 begins its downward movement, but the intake stroke and the like that start again thereafter repeat the above-mentioned cycle from the beginning.

The crank chamber 10 shown in FIG. 1 is of a closed type and functions as an air pump.

A heater 1 is installed in the conduit 13 that sends secondary air to the crank chamber 10.
4, it is possible to raise the temperature of the secondary air flowing into the cylinder 2 during cold weather.

The adjustment valve 17 is a valve for fine adjustment in the case of partial load, and the one shown in FIG. The pump valve function was achieved by opening and closing the secondary air inlet port 16, but instead of providing the secondary air port 16 at the bottom of the cylinder, a check valve (non-rethane valve) 18 was installed in the crank chamber. This is an example of a pump being installed.

The above secondary air supply means utilizes the pump pressure in the crank chamber 10 caused by the vertical movement of the piston, but as shown in FIG. 4, the outlet of the secondary air supply pipe 16 is connected to the port 9, and this A blower 19 and an air cleaner 20 may be provided in the pipe 16.

According to this invention, although it is a four-cycle engine,
The rich air-fuel mixture is sucked into the first chamber 1 through the intake valve 5 provided at the top of the cylinder and into the upper part of the cylinder 2 through the first chamber 1, and then flows into the port 9 provided in the lower part of the cylinder. The secondary air is pushed up to the top of this cylinder 2 to create a stratified or non-homogeneous mixture, and by igniting this rich mixture, a lean mixture of 19 to 21:1 is created as a whole. Regardless of the amount of fuel, it can be completely combusted, the exhaust gas pollutants such as NOx, CO, and HC can be extremely reduced, and the economic effects are also high.

If the air in the crank chamber 10 is used as the secondary air introduced from the port 9, the contaminants in the crank chamber 10 will be sent into the cylinder 2 together with the secondary air, so countermeasures against contaminants in the blow-by gas will be solved at the same time. be done.

The piston 7 is passed through the port 16 provided in the lower part of the cylinder.
While the cylinder is near the bottom dead center, the air to be sent into the cylinder 2 or the mixture of air mixed with water, exhaust gas, and additives is pumped by a Roots blower or air pump in addition to the air pump by the crankcase 10. can be preloaded and fed by a blower such as a centrifugal blower.

In the case of the present invention, in order to burn an extremely lean mixture,
CO, HC in exhaust gas. Because it is designed to minimize HOx, the calorific value is small, and the average effective pressure is also low. By prepressing the intake pressure, the output per cylinder volume can be increased, making it possible for this type of engine to Can compensate for deficiencies.

This invention is not limited to the above embodiments, but can be applied to a wide range of applications without departing from the gist of the invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional elevational view showing an example of a four-cycle internal combustion engine according to the present invention, FIG. 2 is a diagram showing an exhaust gas concentration curve versus air-fuel ratio and an air-fuel ratio of gas in a cylinder, and FIG. FIG. 4 is a schematic diagram showing another embodiment according to the invention. In the drawing, 1 is the first chamber, 2 is the cylinder, 3 is the spark plug, 4 is the intake hole, 5 is the intake valve, 6 is the injection hole in the first chamber, 7 is the piston, 8 is the carburetor, and 9 is the second chamber. Secondary air port, 10 is a crank chamber, 11 is an exhaust valve, 12 is an exhaust hole, 13 is a secondary air conduit,
14 is a heater (heat exchanger), 15 is an air cleaner, 1
6 is a secondary air (to the crank chamber) supply port, 17 is a secondary air amount adjustment valve, 18 is a crank chamber check valve, 19 is a secondary air blower, and 20 is an air cleaner.

Claims (1)

[Claims] 1. In a four-cycle reciprocating internal combustion engine, a first chamber having an ignition plug and a rich mixture intake valve is provided at the top of the cylinder, and during the intake stroke, the second chamber is injected through the first chamber. That is, a port is provided in the lower part of the cylinder wall for sucking in a rich mixture into the main air and pressurizing the air or mixture into the cylinder near the bottom dead center of the piston, and a press-in device is connected to this port. , a four-cycle internal combustion system characterized by forming a stratified mixture in which the mixture becomes rich near the ignition plug when ignited and becomes leaner as the distance from the ignition plug increases, thereby making it possible to burn a lean mixture as a whole. institution. 2. In a four-stroke reciprocating internal combustion engine, a first chamber having an ignition plug and a rich mixture intake valve is provided at the top of the cylinder, and during the intake stroke, air flows through the first chamber to the second chamber, that is, the main air. A port is provided in the lower part of the cylinder wall for sucking in a rich mixture and pressurizing air or the mixture into the cylinder near the bottom dead center of the piston, and a press-in device is connected to this port, and the port is connected to the cylinder wall. When ignited, the fuel mixture is tilted in the tangential direction, forming a stratified mixture in which the mixture becomes rich near the spark plug and becomes leaner as it gets farther from the spark plug, making it possible to burn a lean mixture as a whole. A four-stroke internal combustion engine characterized by: