US3448727A - Exhaust device for rotary piston engine - Google Patents
Exhaust device for rotary piston engine Download PDFInfo
- Publication number
- US3448727A US3448727A US713029A US3448727DA US3448727A US 3448727 A US3448727 A US 3448727A US 713029 A US713029 A US 713029A US 3448727D A US3448727D A US 3448727DA US 3448727 A US3448727 A US 3448727A
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- US
- United States
- Prior art keywords
- exhaust
- port
- rotary piston
- piston engine
- exhaust device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B55/00—Internal-combustion aspects of rotary pistons; Outer members for co-operation with rotary pistons
- F02B55/16—Admission or exhaust passages in pistons or outer members
Definitions
- This invention relates to an improved exhaust device for rotary piston engines.
- the first Way which is known as a peripheral exhaust type
- a single exhaust port is provided on the center housing, through which port the Working fluid is exhausted
- the second Way which is known as a side exhaust type
- a single exhaust port is provided on the side housing, through which port the working fluid is exhausted.
- the side exhaust type in regard to exhaust efliciency which effects the output efficiency of the engine, as the working fluid is rapidly exhausted through the exhaust port, because the passage resistance is small and it is possible to make a sudden change in the opening area of the exhaust port from the beginning of the opening to its complete opening.
- An object of the present invention is to provide an improved exhaust device of the peripheral exhaust type for the rotary piston engines having a superior exhaust efficiency and a high output power.
- Another object of the present invention is to provide an improved exhaust device to reduce the occurrence of an unpleasant exhaust noise of especially high frequency.
- the exhaust port on the center housing consists of a plurality of ports, each having a comparatively small opening area so as to prevent the occurrence of the turbulent flow caused by 'ice the abrupt increase of opening rate of the exhaust port as the rotor rotates and by the sudden expansion of the working fluid accompanying the opening of the exhaust port and especially, to prevent the occurrence of high frequencyexhaust noise caused thereby.
- FIG. 1 shows vertical section front view of a rotary piston engine equipped with an embodiment of the exhaust device in accordance with the present invention
- FIG. 2 is a partial side view of the device of- FIG. 1 illustrating the exhaust ports
- FIG. 3 shows another embodiment of the exhaust device of the present invention.
- FIG. 4 shows a graph in which a comparison is made on the sound pressure of the exhaust noise versus frequency between the rotary engine equipped with the exhaust device according to the present invention and the conventional rotary engine.
- 1 is a center housing with a polyarciform inner face; 2 and 2, side housings fitted on both sides of center housing 1; 3, the polygonal rotor that is supported by eccentric shaft 4 and makes a planetary rotation inside the casing consisting of the center housing 1 and the side housings 2, 2; 5 is an intake port provided on the center housing 1; 6a, 6b and 6c are the exhaust ports which are provided on the center housing, separated by partitions 7a and 7b, respectively, and designed so that these exhaust ports successively communicate with working chamber 8 accompanied with the rotation of rotor 3.
- the opening rate of the exhaust ports shows a comparatively gradual increase with the rotation of rotor 3 and, at the same time, exhaust port 6a, which is separated from port 6b by partition 711, has a comparatively small opening area when it is opened and the working fluid in working chamber 8 is exhausted. Therefore, the working fluid does not expand suddenly in the port 6a, and when the rotor 3 further rotates, exhaust ports 6b and 60 will open successively in this order and the Working fluid pressure will decrease gradually, so that it is possible to prevent a high frequency exhaust noise from occurring.
- FIG. 3 Another embodiment shown in FIG. 3 is similar to the foregoing embodiment shown in FIG. 2, and as the rotor 3 rotates, exhaust ports 6a, 6b and 60, which are separated by partitions 7a and 7b, open in this order and, in consequence, the working fluid pressure in the working chamber decreases gradually.
- the opening rate of the exhaust ports is changed by designing the exhaust ports such that, after exhaust port 6a begins to open and opens to some extent, exhaust port 6b begins to open, and before exhaust port 6!) is fully opened, exhaust port 60 begins to open.
- the opening rate of the exhaust port is comparatively gradual and there is no danger of turbulent flow occurring in the vicinity of the exhaust ports caused by a sudden expansion of the working fluid, in spite of the fact that the exhaust ports are provided on the center housing. Therefore, the occurrence of an unpleasant exhaust noise, particularly of a high frequency, can be prevented.
- FIG. 4 shows sound pressure on ordinate in db and noise frequency on abscissa in c.p.s.
- the Curve B shows exhaust noise sound pressure taken on the conventional rotary piston engine equipped with a single exhaust port on the center housing
- the Curve C shows that taken on the rotary piston engine equipped with the exhaust device of the present invention.
- the Curve C shows that the noise sound pressure is significantly decreased in comparing to the Curve B especially in high frequency nozzle range.
- a rotary piston engine comprising a casingcom prising two parallelly arranged side housings and a center housing mounted therebetween, and a rotor supported by an eccentric shaft so as to planetarily rotate within the casing to perform the steps of intake, compression, explosion and exhaust of a working fluid, an exhaust device having a plurality of exhaust ports provided on the center housing with partitions separating these ports from each other, the exhaust ports being successively opened as the rotor rotates.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Silencers (AREA)
- Tires In General (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
Description
June 10, 1969 TAKAHARU KOBAYAKAWA 3,443,727
EXHAUST DEVICE FOR ROTARY PISTON ENGINE Sheet 1 of 2 Filed March 14, 1968 vFIG! FIG.2
June 10, 1969 TAKAHARUKOBAYAKAWA 3,448,727
EXHAUST DEVICE FOR ROTARY PISTON ENGINE Filed March 14, 1968 Sheet 2 of 2 SOUND PRESSURE (db) FREQUENCY (cps) United States Patent US. Cl. 123-8 3 Claims ABSTRACT OF THE DISCLOSURE This invention provides an improved exhaust device for rotary piston engine to reduce the occurrence of the exhaust noise when the working fluid is exhausted, and the improvement resides in that a plurality of exhaust ports divided by partitions are provided on the center housing of the casing, the exhaust ports being successively opened as the rotor rotates.
This invention relates to an improved exhaust device for rotary piston engines.
Generally, with a rotary piston engine in which each process, such as intake, compression and explosion of the working fluid and exhaust, is performed by the planetary rotating motion of a polygonal rotor in a casing which comprises two parallel side housings and a center housing having a polyarciform inner face interposed between them, there are two ways in exhausting the working fluid.
According to the first Way, which is known as a peripheral exhaust type, a single exhaust port is provided on the center housing, through which port the Working fluid is exhausted, while according to the second Way, which is known as a side exhaust type, a single exhaust port is provided on the side housing, through which port the working fluid is exhausted. Each of the aforesaid two ways has its merits and defects, however, in view of the basic structure of this type of engine, the first Way, i.e. the peripheral exhaust type is known to be superior to the second way, i.e. the side exhaust type, in regard to exhaust efliciency which effects the output efficiency of the engine, as the working fluid is rapidly exhausted through the exhaust port, because the passage resistance is small and it is possible to make a sudden change in the opening area of the exhaust port from the beginning of the opening to its complete opening.
In the past, a single port with the necessary area of opening had been adopted as the exhaust port on the center housing. This is excellent in exhaust efficiency, as mentioned above, but, at the same time, as the opening ratio of the exhaust port increases sharply with the rotation of the rotor and the expansion ratio of the working fluid in the working chamber becomes large simultaneously with the opening of the exhaust port, a turbulent flow occurs in the vicinity of the exhaust port, which results in making it impossible to prevent an unpleasant exhaust noise, e.g. from the order of to 10 c.p.s., and especially high frequency noise from occurring.
An object of the present invention is to provide an improved exhaust device of the peripheral exhaust type for the rotary piston engines having a superior exhaust efficiency and a high output power.
Another object of the present invention is to provide an improved exhaust device to reduce the occurrence of an unpleasant exhaust noise of especially high frequency.
In accordance with the present invention, the exhaust port on the center housing consists of a plurality of ports, each having a comparatively small opening area so as to prevent the occurrence of the turbulent flow caused by 'ice the abrupt increase of opening rate of the exhaust port as the rotor rotates and by the sudden expansion of the working fluid accompanying the opening of the exhaust port and especially, to prevent the occurrence of high frequencyexhaust noise caused thereby.
The present invention will be described more in detail referring to illustrative embodiments shown'in the drawing, in which:
FIG. 1 shows vertical section front view of a rotary piston engine equipped with an embodiment of the exhaust device in accordance with the present invention;
FIG. 2 is a partial side view of the device of- FIG. 1 illustrating the exhaust ports;
FIG. 3 shows another embodiment of the exhaust device of the present invention; and
FIG. 4 shows a graph in which a comparison is made on the sound pressure of the exhaust noise versus frequency between the rotary engine equipped with the exhaust device according to the present invention and the conventional rotary engine.
In FIGS. 1 and 2, 1 is a center housing with a polyarciform inner face; 2 and 2, side housings fitted on both sides of center housing 1; 3, the polygonal rotor that is supported by eccentric shaft 4 and makes a planetary rotation inside the casing consisting of the center housing 1 and the side housings 2, 2; 5 is an intake port provided on the center housing 1; 6a, 6b and 6c are the exhaust ports which are provided on the center housing, separated by partitions 7a and 7b, respectively, and designed so that these exhaust ports successively communicate with working chamber 8 accompanied with the rotation of rotor 3.
In such a structure, the opening rate of the exhaust ports shows a comparatively gradual increase with the rotation of rotor 3 and, at the same time, exhaust port 6a, which is separated from port 6b by partition 711, has a comparatively small opening area when it is opened and the working fluid in working chamber 8 is exhausted. Therefore, the working fluid does not expand suddenly in the port 6a, and when the rotor 3 further rotates, exhaust ports 6b and 60 will open successively in this order and the Working fluid pressure will decrease gradually, so that it is possible to prevent a high frequency exhaust noise from occurring.
Another embodiment shown in FIG. 3 is similar to the foregoing embodiment shown in FIG. 2, and as the rotor 3 rotates, exhaust ports 6a, 6b and 60, which are separated by partitions 7a and 7b, open in this order and, in consequence, the working fluid pressure in the working chamber decreases gradually. However, in this embodiment, the opening rate of the exhaust ports is changed by designing the exhaust ports such that, after exhaust port 6a begins to open and opens to some extent, exhaust port 6b begins to open, and before exhaust port 6!) is fully opened, exhaust port 60 begins to open.
As the present invention was designed in the structure mentioned above, the opening rate of the exhaust port is comparatively gradual and there is no danger of turbulent flow occurring in the vicinity of the exhaust ports caused by a sudden expansion of the working fluid, in spite of the fact that the exhaust ports are provided on the center housing. Therefore, the occurrence of an unpleasant exhaust noise, particularly of a high frequency, can be prevented.
FIG. 4 shows sound pressure on ordinate in db and noise frequency on abscissa in c.p.s. The Curve B shows exhaust noise sound pressure taken on the conventional rotary piston engine equipped with a single exhaust port on the center housing, while the Curve C shows that taken on the rotary piston engine equipped with the exhaust device of the present invention. As apparent from the graph, the Curve C shows that the noise sound pressure is significantly decreased in comparing to the Curve B especially in high frequency nozzle range.
What is claimed is:
1. In a rotary piston engine comprising a casingcom prising two parallelly arranged side housings and a center housing mounted therebetween, and a rotor supported by an eccentric shaft so as to planetarily rotate within the casing to perform the steps of intake, compression, explosion and exhaust of a working fluid, an exhaust device having a plurality of exhaust ports provided on the center housing with partitions separating these ports from each other, the exhaust ports being successively opened as the rotor rotates.
2. The exhaust device according to claim 1, in which a 3; The exhaust device according to claim 1, in which a succeeding port will begin to open after a preceding port is opened to some extent.
References Cited UNITED STATES PATENTS 0 CARLTON R. CROYLE, Primary Examiner.
-D. HART, Assistant Examiner.
US. Cl. X.R.
succeeding port will open just after a preceding port is 15 91-56 fully opened.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1777767 | 1967-03-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3448727A true US3448727A (en) | 1969-06-10 |
Family
ID=11953130
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US713029A Expired - Lifetime US3448727A (en) | 1967-03-20 | 1968-03-14 | Exhaust device for rotary piston engine |
Country Status (4)
Country | Link |
---|---|
US (1) | US3448727A (en) |
DE (1) | DE1601837B1 (en) |
FR (1) | FR1557378A (en) |
GB (1) | GB1213718A (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3894819A (en) * | 1973-07-18 | 1975-07-15 | Toyota Motor Co Ltd | Exhaust port of a rotary piston engine |
US3954356A (en) * | 1974-11-01 | 1976-05-04 | General Motors Corporation | Rotary engine rotor housing having coolant cooled bridged exhaust port |
US3981643A (en) * | 1974-11-29 | 1976-09-21 | General Motors Corporation | Rotary combustion engine two-piece apex seal arrangement |
US4054400A (en) * | 1976-04-08 | 1977-10-18 | Caterpillar Tractor Co. | Engine port bridging |
US4308002A (en) * | 1979-10-25 | 1981-12-29 | Alfonso Di Stefano | Wankel-type engine with semi-circular sectional configuration for chamber end surface |
US4386890A (en) * | 1981-02-02 | 1983-06-07 | Curtiss-Wright Corporation | Delivery valve assembly, especially for rotary compressors |
DE3414987A1 (en) * | 1983-04-19 | 1984-10-25 | Toyo Kogyo Co. Ltd., Hiroshima | EXHAUST OPENING TRAINING FOR CYLINDER ENGINES |
DE3643717A1 (en) * | 1985-12-20 | 1987-10-22 | Tanazawa Hakkosha Kk | PLASTIC PROFILE FORM AND METHOD FOR THEIR PRODUCTION |
US20130247866A1 (en) * | 2012-03-22 | 2013-09-26 | Eugene Gekht | Port for rotary internal combustion engine |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0203973A1 (en) * | 1984-12-10 | 1986-12-10 | DAVIES, Bryan John | Rotary engine with external combustion chamber |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3075505A (en) * | 1959-04-23 | 1963-01-29 | Nsu Motorenwerke Ag | Port construction for rotary combustion engine |
US3103208A (en) * | 1960-06-07 | 1963-09-10 | Curtiss Wright Corp | Intake port construction for rotary mechanisms |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2720904B2 (en) * | 1990-08-31 | 1998-03-04 | 富士通株式会社 | Self-describing database management system configuration method and development / modification method |
-
1968
- 1968-03-13 DE DE19681601837 patent/DE1601837B1/en not_active Withdrawn
- 1968-03-14 US US713029A patent/US3448727A/en not_active Expired - Lifetime
- 1968-03-19 GB GB03358/68A patent/GB1213718A/en not_active Expired
- 1968-03-20 FR FR1557378D patent/FR1557378A/fr not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3075505A (en) * | 1959-04-23 | 1963-01-29 | Nsu Motorenwerke Ag | Port construction for rotary combustion engine |
US3103208A (en) * | 1960-06-07 | 1963-09-10 | Curtiss Wright Corp | Intake port construction for rotary mechanisms |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3894819A (en) * | 1973-07-18 | 1975-07-15 | Toyota Motor Co Ltd | Exhaust port of a rotary piston engine |
US3954356A (en) * | 1974-11-01 | 1976-05-04 | General Motors Corporation | Rotary engine rotor housing having coolant cooled bridged exhaust port |
US3981643A (en) * | 1974-11-29 | 1976-09-21 | General Motors Corporation | Rotary combustion engine two-piece apex seal arrangement |
US4054400A (en) * | 1976-04-08 | 1977-10-18 | Caterpillar Tractor Co. | Engine port bridging |
US4308002A (en) * | 1979-10-25 | 1981-12-29 | Alfonso Di Stefano | Wankel-type engine with semi-circular sectional configuration for chamber end surface |
US4386890A (en) * | 1981-02-02 | 1983-06-07 | Curtiss-Wright Corporation | Delivery valve assembly, especially for rotary compressors |
DE3414987A1 (en) * | 1983-04-19 | 1984-10-25 | Toyo Kogyo Co. Ltd., Hiroshima | EXHAUST OPENING TRAINING FOR CYLINDER ENGINES |
US4543926A (en) * | 1983-04-19 | 1985-10-01 | Mazda Motor Corporation | Exhaust port structure for rotary piston engines |
DE3643717A1 (en) * | 1985-12-20 | 1987-10-22 | Tanazawa Hakkosha Kk | PLASTIC PROFILE FORM AND METHOD FOR THEIR PRODUCTION |
US20130247866A1 (en) * | 2012-03-22 | 2013-09-26 | Eugene Gekht | Port for rotary internal combustion engine |
US8905736B2 (en) * | 2012-03-22 | 2014-12-09 | Pratt & Whitney Canada Corp. | Port for rotary internal combustion engine |
Also Published As
Publication number | Publication date |
---|---|
GB1213718A (en) | 1970-11-25 |
DE1601837B1 (en) | 1971-10-21 |
FR1557378A (en) | 1969-02-14 |
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