JPS63162939A - Exhaust port structure for rotary piston engine - Google Patents

Abstract

PURPOSE:To dilute exhaust gas flowing in an actuating chamber being under a suction stroke and to enable prevention of income of exhaust gas, by a method wherein during overlap of suction with exhaust, secondary air is injected through the leading side of an exhaust port opening part. CONSTITUTION:During a time when actuating chambers 3A and 3B are intercommunicated through an exhaust port opening part 4a, exhaust gas in the actuating chamber 3A is exhausted through an exhaust port 4, and a part of exhaust gas flows through an exhaust port opening part 4a to the actuating chamber 3B and is mixed with intake air. However, since secondary air introduced to a secondary air feed passage 9 is injected, as shown by an arrow mark 16, through a nozzle 10 and flows in the actuating chamber 3B together with exhaust gas, the exhaust gas is diluted to reduce the pollution level of intake air. Besides, a secondary air flow injected through the nozzle 10 forms an air curtain to shut off income of the exhaust gas to the actuating chamber 3B, and thereby a pollution level is further reduced. This constitution performs the explosion stroke of the actuating chamber 3B by means of intake air being in a state approximately similar to a normal state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an exhaust port structure for a rotary piston engine, and more particularly to an exhaust port structure in which an exhaust port insert is inserted.

(Prior art) A rotary piston engine exhaust system in which a cylindrical exhaust port insert is inserted into an exhaust port having an opening on the trochoid inner peripheral surface of a rotor housing, leaving a gap for secondary air supply on its outer periphery. The port structure is from the 1980s.
It is disclosed in the publication No.-108727. According to the above configuration, since there is a gap between the outer periphery of the exhaust port insert and the inner periphery of the exhaust port, there is a gap between the outer periphery of the exhaust port insert and the inner periphery of the exhaust port. This reduces the influence of the exhaust gas passing through the exhaust port, thereby avoiding a drop in the temperature of the exhaust gas passing through the exhaust port, and promoting the reaction that accumulates in the exhaust gas purification device provided in the exhaust pipe. In addition, oxygen is replenished by the secondary air introduced into the gap, and the reaction in the exhaust gas purification device is promoted.

On the other hand, in a rotary piston engine, during the overlap period in which the working chamber in the intake stroke and the working chamber in the exhaust stroke communicate through the opening of the exhaust port, exhaust gas flows from the working chamber in the exhaust stroke to the opening of the exhaust port. There is a phenomenon where secondary air flows into the working chamber during the intake stroke through the gap, reducing ignition performance and making idle rotation unstable. It is known that the incoming exhaust gas is diluted, reducing the exhaust gas contamination of the intake air, and maintaining normal combustion in the subsequent combustion stroke.

However, when introducing secondary air into the gap formed on the outer periphery of the exhaust port insert, the cooling water passage and bolt insertion holes are opened around the exhaust boat, so the secondary air is introduced into the gap formed on the outer periphery of the exhaust port insert. It is necessary to provide an air passage that supplies air from the bottom of the rotor housing to the inside of the rotor housing and reaches the bottom of the exhaust port insert. It had to be formed at a position away from the surface. Therefore, only a small amount of secondary air is blown into the working chamber during the intake stroke, and there is a problem in that the exhaust gas dilution effect in the intake air by the secondary air during the overlap period as described above cannot be sufficiently obtained.

(Object of the Invention) In view of the above circumstances, the present invention is capable of sufficiently diluting the exhaust gas flowing into the working chamber during the intake stroke during the overlap period with secondary air, and further diluting the exhaust gas. It is an object of the present invention to provide an exhaust port structure for a rotary piston engine that also allows the inflow to be blocked by a secondary air flow.

(Structure of the Invention) Therefore, in the present invention, a cylindrical exhaust port insert is inserted into an exhaust port having an opening on the inner peripheral surface of the trochoid of the rotor housing, leaving a gap for secondary air supply on the outer periphery of the exhaust port insert. In the exhaust port structure of a rotary piston engine, a secondary air supply passage is provided inside the exhaust port insert, and the secondary air that has passed through the rotor housing and reached the gap is fed to the secondary air supply passage. an inlet for introducing the secondary air into the secondary air supply passage, and an inlet for introducing the secondary air from the secondary air supply passage to the short axis side of the trochoid at the opening of the exhaust port, that is, on the leading side with respect to rotor rotation. The above object is achieved by forming an outlet for leading out the air.

(Effects of the Invention) According to the present invention, the exhaust gas flowing from the working chamber side in the exhaust stroke to the working chamber side in the intake stroke through the opening of the exhaust port during the overlap period of the intake and exhaust gases flows through the opening of the exhaust port. The secondary air ejected from the secondary air outlet formed on the leading side of the chamber is reliably diluted, and since this secondary air flow forms an air curtain, the exhaust gas towards the working chamber during the intake stroke is diluted. It is also possible to block the inflow of

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a rotary piston engine including the exhaust port structure of the present invention, which has a trochoidal inner circumferential surface 1a, and three working chambers are formed by a rotor 2 that performs planetary rotational motion along this inner circumferential surface 1a. The rotor housing l in which the rotor housing 3 is formed is provided with an exhaust port 4 having an opening 4a on the trochoid inner circumferential surface 1a. Further, an intake boat 6 is opened in one side housing 5, which is attached to sandwich the rotor housing l.

As shown in FIGS. 2 and 3, a cylindrical exhaust port insert 7 is inserted into the exhaust port 4, leaving a gap 8 around its outer periphery. This exhaust port insert 7
has a double structure at its central portion with an outer cylinder 7a and an inner cylinder 7b, and an annular secondary air supply passage 9 is formed by the gap between the outer cylinder 7a and the inner cylinder 7b. There is. The end of the secondary air supply passage 9 opposite to the exhaust boat opening 4a is closed, and the exhaust boat opening 4a is closed.
The side ends are also closed except for the leading side with respect to rotor rotation, that is, the short axis side of the trochoidal curve forming the inner circumferential surface 1a of the rotor housing 1. Then, only the outer cylinder 7a and the inner cylinder 7b on the leading side are extended toward the leading side of the exhaust boat opening 4a to form a nozzle 10, and this nozzle 10 supplies secondary air to the secondary air supply passage 9. A secondary air outlet 11 is formed for blowing out the air from the air into the working chamber 3.

On the other hand, the rotor housing l includes a secondary air supply passage 9 formed by the outer cylinder 7a and the inner cylinder 7b of the exhaust port insert 7, and a gap 8 formed on the outside of this passage 9.
On the other hand, an air passage 12 for supplying secondary air from an air pump is provided, and this air passage 12 opens into the gap 8 at an opening 12a. The outer cylinder 7a of the exhaust port insert 7 has the opening 12a.
A secondary air introduction port 13 for introducing secondary air into the passage 9 is provided at a position facing the secondary air introduction port 13 .

Therefore, the secondary air supplied from the air passage 12 flows into the gap 8 through the inlet 13, enters the passage 9 from the inlet 13, and is ejected from the nozzle 1°.

The above is an example of the configuration of the exhaust port structure according to the present invention, and the combustion gas exploded and expanded by the ignition of the eight spark plugs I4, the operation of which will be explained next, causes the rotor 2 to rotate in the direction of the arrow 15. As the rotor 2 rotates to the position shown in FIG. 2, the working chamber 3A begins to enter the exhaust stroke;
The working chamber 3B on the leading side with respect to A begins to enter the intake stroke, and the working chambers 3A and 3''B are connected to the exhaust boat opening 4a.
This is an overlapping period that communicates through. Therefore, the exhaust gas in the working chamber 3A is exhausted through the exhaust port 4, and a portion of this exhaust gas flows into the leading side working chamber 3B through the exhaust boat opening 4a and mixes with the intake air. However, the secondary air introduced into the secondary air supply passage 9 is ejected from the nozzle 10 as shown by the arrow 16 and flows into the working chamber 3B together with the exhaust gas, so the exhaust gas is diluted and the intake air is contaminated. degree is reduced. Moreover, since the secondary air flow G±air curtain ejected from the nozzle 10 is formed to block the exhaust gas from flowing into the working chamber 3B, the degree of contamination of the intake air is further reduced.

Therefore, the explosion stroke in the working chamber 3B is performed with intake air in a state close to normal, and a decrease in engine output can be avoided.

On the other hand, during the exhaust stroke, the secondary air ejected from the nozzle 10 and the secondary air flowing out from the gap 8 flow out from the exhaust port 4 together with the exhaust gas, and the exhaust gas purifier installed in the exhaust pipe downstream of the exhaust port 4 introduced into the device. Since the exhaust port insert 7 is inserted into the exhaust port 4 with a gap 8 left for supplying secondary air, the exhaust port insert 7 does not come into direct contact with the rotor housing 1 which is being cooled. Exhaust boat insert 7
The temperature of the exhaust gas flowing therein is maintained, and the above-mentioned secondary air supplies oxygen for combustion in the purification device to promote the purification reaction.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a rotary piston engine to which the exhaust port structure of the present invention is applied, Fig. 2 is an enlarged sectional view of its main parts, and Fig. 3 is a sectional view taken along the ■-■ stripes in Fig. 2. , 4th
The figure is a front view of the exhaust boat opening. 1-...Rotor housing 4...Exhaust boat 7-
Exhaust port insert 7a--outer cylinder 7b...-inner cylinder 8-gap 9--secondary air supply passage 10--nozzle 11-2
Secondary air outlet 12...-Air passage 13...Secondary air inlet

Claims (1)

[Claims] A rotary piston engine in which a cylindrical exhaust port insert is inserted into an exhaust port having an opening on the trochoid inner circumferential surface of a rotor housing, leaving a gap for secondary air supply on its outer periphery. In the exhaust port structure, a secondary air supply passage is provided inside the exhaust port insert, and the secondary air passing through the rotor housing and reaching the gap is transferred to the secondary air supply passage. A rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary machine characterized by forming an inlet for introducing the secondary air into the secondary air supply passageway Piston engine exhaust port structure.