JPS6323544Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to four-stroke internal combustion engines for automobiles and other vehicles. The applicant of this application previously developed an engine of this type with a throttle valve and a check valve downstream of the throttle valve, which allows intake air to flow in but prevents reverse flow, in the intake passage that is connected to the cylinder of the engine via the intake valve. Thus, we have proposed a formula that is intended to improve the output characteristics of the engine, particularly in the low speed range. (Refer to Japanese Patent Publication No. 47-50884.) The present invention relates to an improvement of this type of engine, and includes an intake passage 4 that is connected to the cylinder 2 of a four-cycle engine through an intake valve 3, and that includes: In an internal combustion engine that includes a throttle valve 6 and a check valve 7 located downstream of the throttle valve 6 to allow inflow of intake air but prevent reverse flow, the intake passage 4 is provided in the vicinity of the check valve 7. It is characterized by comprising a chamber 10 that opens upstream of the check valve 7.

Embodiments of the present invention will be explained with reference to attached drawings.

In the drawings, 1 is an engine, and 2 is a cylinder thereof.A throttle valve 6 in a carburetor 5 and intake air downstream of the throttle valve 6 in a carburetor 5 are allowed to flow into an intake passage 4 that is connected to the cylinder 2 via an intake valve 3. However, it is equipped with a check valve 7 that prevents backflow. The check valve 7 is made of a reed valve, for example, and has a lead 7b on the valve body 7a, and a presser spacer 8 on the back side thereof. In the drawings, reference numeral 9 indicates an air cleaner at the upper end of the intake passage 4.

The above is not particularly different from what was proposed earlier, and the check valve 7 acts to improve the output characteristics of the engine 1, especially in the low speed range, but according to the present invention,
In this device, the intake passage 4 is provided with a chamber 10 inserted into the passage 4 at an intermediate portion between the throttle valve 6 and the check valve 7. In the illustrated spacer 8, a pipe 8a extending laterally is provided, and a chamber 10 prepared separately in advance is fitted at the open end of the chamber 10 to be inserted into the passage 4. The chamber 10 may be made of iron or other metal, rubber or other elastic material, etc., and its volume is, for example, about 200 c.c. when the engine 1 is a 50 c.c. single cylinder. . To explain its operation, for example, it is as shown in FIGS. 2 to 4,
The chamber 10 performs a respiratory function. That is, during the intake process of the engine 1, the check valve 7 opens as shown in the second figure, and the air-fuel mixture is guided into the cylinder 22 through it, and at this time, a negative suction pressure is generated on the upstream side of the check valve 7, which causes a negative pressure in the chamber 10. Also becomes negative pressure. Next, considering the case where the valve 7 closes near the end of the suction process, some negative suction pressure remains in the chamber 10,
This negative pressure sucks the air-fuel mixture from the carburetor 5 as shown in the third figure, and the chamber 10 is filled with the air-fuel mixture. When the next intake stroke is reached, the air-fuel mixture in this chamber 10 is led into the cylinder 2 together with the air-fuel mixture from the carburetor 5, as shown in FIG. The supply increases its suction efficiency and improves its output characteristics. In this case, since the engine is a 4-cycle engine, at the end of the intake stroke shown in the third figure, the intake valve 3 and the check valve 7 are closed, so that the chamber a between the two valves is closed.
Both the chamber b in the chamber 10 and the chamber c between the check valve 7 and the throttle valve 6 are in a negative pressure state, but the chamber b in the chamber 10 is closed and the air-fuel mixture is not allowed to flow as shown in the second figure. Because of the outflow, the degree of negative pressure is extremely significant, and the check valve 7 and throttle valve 6
The air-fuel mixture in between flows into the chamber c due to inertia, so the pressure is close to atmospheric pressure. A negative pressure difference occurs between the check valve 7 and the check valve 7, but in this case, the check valve 7 has a chamber b in the chamber 10 with a high degree of negative pressure near the upstream side of the check valve 7.
Since the chamber 10 is open, the above-mentioned fluttering can be effectively prevented, and the air-fuel mixture from the chamber 10 generates a vortex in the intake passage 4 to agitate the air-fuel mixture and improve its atomization. Further, this chamber 10 acts to reduce the pumping output required for intake by the engine 1, and is effective in improving fuel efficiency. That is, as described above, the chamber 10 sucks the air-fuel mixture into it in advance due to some residual suction negative pressure, and then this air-fuel mixture is guided to the cylinder 2 together with the air-fuel mixture from the carburetor 5 in the intake process. , acts to reduce the pumping horsepower required for suction in the suction stroke of the engine 1.

In addition, according to the experiments of the present invention, it was confirmed that the engine of the present invention is excellent in output characteristics as shown in FIGS. 5 and 6, and is also excellent in fuel efficiency as shown in FIG. 7. That is, Figures 5 and 6 are output characteristic diagrams when the throttle valve 6 is half open and fully open, where A is the output characteristic of the conventional conventional engine and B is the output characteristic of the previously proposed engine with a check valve. The output characteristic of the engine, C, is the output characteristic of the present invention. Furthermore, FIG. 7 is a fuel efficiency characteristic diagram, in which A shows the case of a normal type engine, B shows the case of the engine with a check valve, and C shows the case of the present invention.

As described above, according to the present invention, the intake passage 4 of a four-cycle engine in which the throttle valve 6 and the check valve 7 are provided in front and behind each other is provided with a chamber 10 that opens close to the check valve 7. Therefore, the air-fuel mixture in the chamber 10 has a breathing effect, increasing the suction efficiency of the 4-cycle engine and improving the output characteristics, as well as reducing the suction horsepower and improving fuel efficiency. Since it opens close to and upstream of the check valve 7, when the breathing action of the chamber 10 is discharged, an excess flow is generated in the intake passage to improve the agitation of the air-fuel mixture, and when the breathing action is inhaled, the The suction negative pressure acts as a tensile force on the back surface of the check valve 7, and the pressure difference between the chamber a between the intake valve 3 and the check valve 7 and the chamber c between the check valve 7 and the throttle valve 5 is large.
Even though the engine is a cycle engine, it has the effect of ensuring that the check valve is closed and preventing the valve from fluttering when the valve is closed.

[Brief explanation of drawings]

Fig. 1 is a cutaway side view of one example of the device of the present invention;
Figures 4 through 4 are explanatory diagrams of the operating principle, and Figure 5.
6 and 6 are output characteristic diagrams, and FIG. 7 is a fuel efficiency characteristic diagram. 1...Engine, 2...Cylinder, 3...Intake valve, 4...Intake passage, 6...Throttle valve, 7...
...Check valve, 10... Chamber.

Claims (1)

[Scope of utility model registration request] Intake valve 3 in cylinder 2 of a 4-stroke engine
An intake passage 4 is provided which is continuous through the intake passage 4.
An internal combustion engine comprising a throttle valve 6 and a check valve 7 located downstream of the throttle valve 6 to allow intake air to flow in but prevent reverse flow.
An internal combustion engine characterized in that the intake passage 4 is provided with a chamber 10 that is close to the check valve 7 and opens upstream of the check valve 7.