JPS5918529B2 - 4-stroke internal combustion engine - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a four-stroke internal combustion engine.

Conventional technology There are two methods used to supply fuel in internal combustion engines: an injection method and a carburetor method, but no matter which method is used, atomization and vaporization of fuel particles can have a large impact on engine performance. Are known.

However, when the air-fuel mixture supplied to the engine cylinder is relatively small, such as when the engine is idling or under light load, no matter which method is used, the flow energy imparted to the air-fuel mixture is small, resulting in atomization of the fuel.・Vaporization is insufficient, and as a result, fuel efficiency is reduced.During idle-link operation of a multi-cylinder engine, it is necessary to supply a rich mixture to each cylinder in order to distribute the combustible mixture to each cylinder. The current situation is that it is inevitable that the number of emissions and harmful emissions will increase.

Recently, a forced heating device for the intake manifold has been used as a countermeasure for this problem, but this device evaporates the liquid fuel and is not very effective in promoting the vaporization of the fuel in the air-fuel mixture that passes through it in a short period of time. It is known.

This is because the cycle strokes (intake, compression, combustion, exhaust) of internal combustion engines have traditionally been open cycles, and therefore the time given to fuel vaporization becomes more restricted as the engine speed increases. There is a fundamental problem in receiving it.

Purpose of the Invention The present invention provides a closed-cycle operation in the intake stroke to provide flow energy and the time necessary for vaporization to the supplied air-fuel mixture when the intake air is small, thereby promoting and activating vaporization. The main purpose is to achieve uniform air-fuel mixture distribution in a multi-cylinder engine by activating vaporization.
The aim is to improve combustion efficiency and reduce harmful components emitted.

Structure of the Invention The structure of the present invention is to provide a throttle valve that responds to the engine load in the intake passage that connects the engine combustion chamber and the carburetor. The partial load passage, which has a small cross-sectional area and long passage length, is branched and the partial load passage is connected again to the suction passage downstream of the throttle valve, and the throttle valve is closed during partial load operation. During operation, the air-fuel mixture flows reciprocally in the partial load passage, increasing the flow energy of the air-fuel mixture and providing the time required for vaporization, thereby promoting the vaporization of the fuel and reducing the The purpose is to activate the vaporized fuel by exchanging heat with the combustion gas of the cycle.

Furthermore, the configuration of the present invention is such that a throttle valve that responds to the engine load is provided in the intake passage that connects the engine combustion chamber and the carburetor, and the cross-sectional area from the intake passage between the carburetor and the nine throttle valves is larger than that of the intake passage. Branch a small partial load passage with a long passage length, connect the partial load passage again to the intake passage downstream of the throttle valve, and connect a pressure regulating vessel equipped with a pressure regulating diaphragm to the partial load passage. Another feature is that the throttle valve is closed during partial load operation to further increase the time required for vaporization using the pressure regulating vessel.

Referring to the drawings, 1 is a combustion chamber, 2 is an intake valve, 3 is an exhaust valve, 4 is a spark plug, 5 is an intake passage forming a passage for high-load operation, 6 is an exhaust passage, and 7 is an intake passage 50. a carburetor attached to the inlet; 8 a throttle valve inserted into the intake passage 5;
Reference numerals 9 indicate partial load passages branched from the intake passage 5 between the carburetor 7 and the throttle valve 8, and these partial load passages 9 are connected to the intake passage 5 again downstream of the throttle valve 8.

The throttle valve 8 and the throttle valve (not shown) of the carburetor 7 are connected to a valve link actuating handle 10, which throttle valve 8 is closed during part-load operation by means of the valve link actuating handle 10;
The valve is opened during high load operation.

As shown in the drawing, the partial load passage 9 has a considerably smaller cross-sectional area and a considerably longer passage length than the intake passage 5, and the partial load passage 9 has a pressure regulating vessel equipped with a pressure regulating diaphragm 11. 12 are connected.

As mentioned above, during partial load operation, the throttle valve 8 is closed, so during the valve overlap period of the intake valve 2 and the exhaust valve 3, the blowback effect of the combustion gas that inevitably occurs at low engine speeds causes the combustion gas to flow in the carburetor 7. The formed air-fuel mixture is supplied into the combustion chamber 1 while reciprocating within the partial load passage 9.

Therefore, during this time, the vaporization of the fuel is promoted, and heat exchange occurs with the high-temperature burnt gas in the intake passage 5 near the combustion chamber 1, resulting in an activating effect, during idling and light loads where vaporization was previously poor. etc., it becomes easier to achieve a stable air-fuel mixture distribution, which improves both ignition and combustibility, which is advantageous for fuel efficiency.In addition, the EGR effect is performed simultaneously during the heat exchange process with burned gas, so the amount of NOx generated is extremely small. .

Furthermore, by connecting the pressure regulating container 12 to the partial load passage 9, the diaphragm 11 is displaced downward in the drawing during the blowback action, so that the air-fuel mixture is transferred to the pressure regulating container 12.
Then, when the air-fuel mixture starts flowing into the combustion chamber 1, the diaphragm 11 moves upward in the drawing, so that the air-fuel mixture accumulated in the pressure regulating vessel 12 flows into the partial load passage 9. being pushed out.

By providing the pressure regulating container 12 in this way, the air-fuel mixture can be temporarily stored, giving more time for vaporization, thus further promoting vaporization of the fuel.

The ability to switch between high and low load flow paths with a simple butterfly valve mechanism is an advantage of the structure of the present invention that cannot be overlooked.

The effects of the present invention are listed below.

1. By making the cross-sectional area of the partial load passage smaller than the cross-sectional area of the intake passage, the air-fuel mixture can be made to flow through the partial load passage at a high speed.

Further, by making the passage length of the partial load passage longer than the passage length of the intake passage, the time that the air-fuel mixture stays in the partial load passage can be increased.

That is, it is possible to lengthen the time it takes for fuel supplied from the carburetor to reach the combustion chamber.

In this way, by increasing the time it takes for the fuel supplied from the carburetor to reach the combustion chamber, the vaporization of the fuel can be promoted accordingly, and during this time, as mentioned above, the air-fuel mixture moves through the part-load passage at a high temperature. Since the fuel is allowed to flow at a high speed, vaporization of the fuel can be sufficiently promoted.

1. Vaporization and activation are promoted, the ignition rate is improved, and stable lean mixture combustion is possible.

(Reduction of COlHC and aldehydes) 1. Uniform mixture distribution to each cylinder of a multi-cylinder engine is possible, which improves torque distribution and reduces vibration.

(Reduction of vibration, improvement of responsiveness) - Lean mixture combustion becomes possible, improving thermal efficiency and reducing harmful exhaust components.

(Fuel efficiency improves and CO1HC decreases) 1. Due to the self-EGR effect, less NOx is generated.

(Reduction in NOx)

[Brief explanation of the drawing]

The figure is a plan view schematically showing a four-stroke internal combustion engine according to the present invention. 1... Combustion chamber, 2... Intake valve, 3... Exhaust valve, 5
... Intake passage, 7... Carburetor, 8... Throttle valve, 9
. . . Partial load passage, 11 . . . Pressure adjustment diaphragm, 12 . . . Pressure adjustment vessel.

Claims (1)

[Scope of Claims] 1. A throttle valve that responds to the engine load is provided in the intake passage that connects the engine combustion chamber and the carburetor, and the intake passage or the intake passage between the carburetor and the throttle valve is also disconnected. A four-cycle cycle in which a partial load passage with a small area and a long passage length is branched and the partial load passage is connected again to the intake passage downstream of the throttle valve, and the throttle valve is closed during partial load operation. Internal combustion engine. 2. A throttle valve that responds to the engine load is provided in the intake passage that connects the engine combustion chamber and the carburetor, and a section from the intake passage between the carburetor and the throttle valve that has a smaller cross-sectional area and a longer passage length than the intake passage. The load passage is branched, the partial load passage is connected again to the intake passage downstream of the throttle valve, and a pressure regulating vessel equipped with a pressure regulating diaphragm is connected to the partial load passage, thereby performing partial load operation. 4. The throttle valve was closed when
cycle internal combustion engine.