JPS5840263Y2 - internal combustion engine - Google Patents

Description

[Detailed description of the invention] The present invention relates to internal combustion engines, and in particular, when exhaust recirculation is provided to reduce NOx emitted from the engine, the air-fuel mixture in the combustion chamber is It provides kinetic energy, increases the flame propagation speed, improves combustion, and
The objective is to obtain a highly efficient engine that suppresses the generation of exhaust pollutants such as Ox and CO2HC and has a low fuel consumption rate.

Mixing ratio of fuel and air: If the engine can be operated stably with a lean mixture by lowering the total fuel consumption, the mixture will burn in the presence of sufficient oxygen, so the above CO, H
Emissions of unburned products such as carbon are small, and the combustion temperature can be kept low, resulting in less NOx.

However, with such a thin air-fuel mixture, it is generally difficult to ignite, and furthermore, the flame propagation speed becomes slow and misfires are likely to occur, making it impossible to expect smooth engine operation.

In addition, in order to further reduce the above NOx, exhaust recirculation, E,
It is known that when the OR is used, the above-mentioned deterioration in ignitability, delay in flame propagation speed, etc. become even more significant.

Therefore, conventionally, (a) a spark plug is installed in the subchamber so that a rich air-fuel mixture is supplied only around the spark plug (
(torch combustion method), (b) one combustion chamber with multiple spark plugs (double ignition method),
Furthermore, in addition to the intake and exhaust valves, a third pulp is provided in the combustion chamber and air is introduced from there to scavenge around the spark plug and ensure ignitability (air direct injection method). ) etc. have been developed.

□−′・. However, all of these methods make the overall structure of the engine extremely complex, which not only increases costs but also deteriorates maintainability.
This is not necessarily a preferable method.

The present invention was developed by focusing on this point, and when the above-mentioned EGR is installed, the air-fuel mixture that is taken into the combustion chamber through the main intake passage is supplied with a secondary air-fuel mixture that bypasses the main intake passage. The air-fuel mixture or air is injected in a jet form from the nozzle in the intake passage, giving intense kinetic energy to the air-fuel mixture in the combustion chamber, thereby activating the air-fuel mixture and increasing the ignitability and flame propagation speed. That is.

In the figure, 1 is an air cleaner, 2 is an intake pipe, 3 is an intake port, and 4 is an intake valve, and the main intake passage from the air cleaner 1 to the intake valve 4 is explained in detail below. A carburetor 5 is disposed inside the engine, and when the intake valve 4 is opened, the air-fuel mixture produced by the carburetor 5 is supplied to the combustion chamber γ of the engine 6.

8 is an exhaust valve, 9 is an exhaust boat, and these are no different from a general engine.

Reference numeral 8 denotes a sub-intake passage, and one end of the sub-intake pipe 21 bypassing the main intake passage K is connected to the throttle valve 10 of the carburetor 5.
Air intake outlet 2 formed directly below the position when fully closed.
2, and the other end is connected to an intake hole 23 formed in the cylinder head 11.

A nozzle 24 is formed at the tip of the intake hole 23, and the nozzle 24 is connected to the valve seat 12 of the intake valve 4.
It opens to the intake port 3 near the.

Further, the sub-intake pipe 21 has a sufficient thickness to prevent a pressure drop in the air (or air-fuel mixture) flowing down therein, while the nozzle 24 is narrowed to have an appropriate diameter.

Further, the axis A of the nozzle 24 is located at the valve seat 1.
2 and the direction passing through the center of the valve head part 13 at the maximum lift of the intake valve 4, the jet ejected from the nozzle 24 is directly injected into the combustion chamber γ, causing a swirl in the cylinder. It is set in the direction of strengthening.

Further, E is an EGR system, and an EGR pipe that connects a gas extraction port 31 formed in the exhaust boat 9 (or an exhaust pipe not shown) and a gas mixing port 32 provided in the intake pipe 2 (or intake port 3). There is a control valve 34 in the middle of 33,
The pressure (negative pressure) generated in the signal port 35 opened directly above the fully closed position of the throttle valve 10 is introduced into the negative pressure chamber 3γ of the control valve 34 through the vacuum pipe 36 to operate the diaphragm 38, and the bottle 39 is activated. Above EGR
The flow rate of the reflux gas flowing through the pipe 33 can now be adjusted.

In the internal combustion engine of the present invention having such a configuration, depending on the opening degree of the throttle -yf:10, while EGR is being performed, the mixture drawn into the combustion chamber 7 through the main intake passage K A jet having a kinetic energy several times to several tens of times that of air is automatically injected from the nozzle 24 of the sub-intake passage S in complete synchronization with EGR.

That is, during idling or extremely low load, NOx emissions are originally low and there is no need to use EGR, but in this case, the throttle valve 10 is in the fully closed position or the Because of the opening degree, the signal port 35 is located above the -1 fio, and the pressure generated in the port 35 is approximately the same as atmospheric pressure, and the diaphragm 3 of the control valve 34
8 does not operate and the bottle 39 keeps the BGR pipe 33 closed, so EGR is not performed.

In addition, in the above operating state, since the intake port 22 is located below the throttle valve 10, the pressures at the intake port 22 and the tip of the nozzle 24 are equal to each other (negative pressure in the intake pipe acts on both). Since there is no pressure difference within the sub-intake passage 8, no jet is ejected from the nozzle 24.

On the other hand, when the throttle valve 10 is rotated by a small angle and opened slightly, the signal port 35 is located downstream of the valve 10, and the intake outlet 22 is located upstream of the valve 10. Appropriate pressures (negative pressure and atmospheric pressure) are generated at each outlet 22.

This generated pressure (negative pressure) causes the control valve 34 to actuate the bottle 39.
Move the EGR pipe 33 to open the EGR.

At the same time, a large pressure difference is created in the sub-intake passage S between the pressure (atmospheric pressure) at the intake outlet 22 and the intake pipe negative pressure at the tip of the nozzle 24, and based on this pressure difference, the intake air is The air is injected from the outlet 22 through the sub-intake pipe 21 and into the nozzle 24 at high speed.

Since the jet ejected from the nozzle 24 passes between the valve seat 12 and the valve head portion 13 and is directly injected into the combustion chamber 7, its velocity component is hardly lost. It can be injected into the combustion chamber γ, imparting intense kinetic energy to the air-fuel mixture, and greatly activating the air-fuel mixture.

Furthermore, when the throttle valve 10 is opened wide, the negative pressure in the intake pipe decreases to approximately atmospheric pressure, and the pressure at the tip of the nozzle 24 and the pressure at the intake outlet 22 become equal, which causes the jet to be ejected. When the pressure difference disappears, the mocha at the signal port 35 cannot move the diaphragm 38, EGR is stopped, and jet ejection is also stopped at the same time.

In this way, when EGR is running, jets can be injected automatically and completely simultaneously with EC)R, imparting intense kinetic energy to the air-fuel mixture and activating it. Therefore, it is possible to sufficiently compensate for the deterioration in ignitability or the decrease in flame propagation speed caused by EGR, and improve the combustion itself to reduce CO2.
, HC, etc., and a high-performance engine with low fuel consumption can be obtained.

In addition, the only parts added to the conventional engine to construct the internal combustion engine of the present invention are the nozzle 24 and the auxiliary intake pipe 21, and the devices are different from the three conventional examples (a), (b), and
Compared to (c), the engine can be made much simpler and cheaper, and furthermore, no additional equipment is required for its control.

Generally, when the throttle valve 10 is fully opened, the intake air itself flowing into the combustion chamber 7 via the main intake passage K has relatively large kinetic energy.
In the state where 0 is almost closed (id link),
Since this kinetic energy is very small, if it is necessary to blow a jet in this state even though EGR is not installed, the auxiliary intake pipe 21 is branched as shown by the dotted line and the throttle 2 is
The main intake passage K... where atmospheric pressure is constantly acting through 5.
- This can be achieved by communicating with the auxiliary air intake outlet 26 provided in the air cleaner 1.

Furthermore, the present invention is applicable not only to engines equipped with a carburetor as shown in the figure, but also to those equipped with a fuel injection device in @death intake passage K instead of a carburetor, by providing a sub-intake passage S.
Similar effects can be obtained.

[Brief explanation of the drawing]

The figure is a partially vertical cross-sectional schematic diagram showing an embodiment of an internal combustion engine according to the present invention. E... EGR system, K main intake passage, 1... Air cleaner, 5... Carburetor, 2... Intake pipe, 3...
Intake boat, 4... Intake valve, 7... Combustion chamber, 10.
...Throttle valve, 12...Valve seat, S...
Sub-intake passage, 21... Sub-intake pipe, 22... Intake outlet, 24... Nozzle, 33... EGR pipe, 35...
・Signal hoard, 34...control valve.

Claims (1)

[Scope of utility model registration request] An internal combustion engine is provided with a throttle valve in a main intake passage leading from an air cleaner to an intake valve via an intake pipe and an intake boat, and one end has a nozzle opening to an intake port in a chamber near the intake valve, The other end is provided with an intake port opening directly below the fully closed position of the throttle valve, and the main intake passage is connected to the main intake passage by connecting the intake port and the nozzle through a sub-intake pipe. In addition to bypassing the passage, a gunar port is provided directly above the fully closed position of the throttle valve in a negative pressure chamber of a control valve disposed in the EGR system that recirculates exhaust gas extracted from the exhaust system to the intake system. The internal combustion engine is characterized in that the exhaust gas recirculation by the EGR and the jet ejection from the nozzle of the auxiliary intake passage are operated in complete synchronization according to the opening degree of the throttle valve.