Patent Application
20150260091
1. Field of Invention
The present invention relates to a cooling fin, and particularly to an external cooling fin for a rotary engine.
2. Description of Related Art
In general, an engine cooling system is mainly categorized into a water-cooling type and an air-cooling type. The air-cooling type has two alternatives, a natural air cooling and a compulsory air cooling. The compulsory air cooling inducts external cooling air by a device (such as a compressor) on heat dissipation, but the natural air cooling, by natural airflow from the vehicle speed.
The rotary engine is unique in its assembly, which includes side housings, housing outer casings, center housing, an eccentric shaft and a rotor. The triangular-shaped rotor is aligned in the housings and mounted on the eccentric shaft which the rotor revolves on, and air breathing through the ports on the center housing.
Due to fewer components, the rotary engine, with rotational motion in operation, has the advantages of compact size in comparison to a 3-cylinder piston engine, with reciprocating motion in operation, and also it characterizes with light weight, low fuel consumption, and high thrust/load. Therefore, ordinary cooling system with a relative large size on the piston engine may not be compatible with a rotary engine. With high heat load over limited surface area, a light-weighted fin to extend the exposed surface area for the rotary engine heat dissipation is designed
In view of the shortcomings of the prior art, it is a primary objective of the present invention to overcome the shortcomings by applying an external cooling fin to a rotary engine, wherein a rotary engine has several coupled cooling fins, tuning-forklike, atop the housings and side housings to enhance heat dissipation efficiency.
To achieve the aforementioned objective, the present invention provides both side housings and rotor center housing which has several tuning-forklike fins atop for lowering the temperature of the rotary engine. The cooling fins are coupled and rooted on the housing along with its outer surface. And the roots of the tuning-fork-like fins can be in regular or irregular shape, equal or unequal width. The length ratio of the fins to the roots is approximately 2:1. 2-tooth tuning fork fins or multi-tooth fins are included in the present invention.
The gap between the fins can be coarse or fine based on the heat distribution on the housings. More fine-distributed fins are required for high heat load at combustion zone than the others. As to the cold zone close to the intake port, it is not a must to have fins.
The cooling fins are aligned to the center of the crank shaft and extended radially outward from the roots on the housing outer casings, orthogonal or with a tilt angle from the surface.
The root and the outward stem of the cooling fin can be integrally formed as a whole, wherein the cooling fin has a thickness from 1 mm to 3 mm, and a length from 5 cm to 10 cm, but the invention is not limited to such arrangements only.
The technical characteristics and objectives of the present invention can be further understood by the following detailed description of preferred embodiments and related drawings.
With reference to
With reference to
Each of the coupled cooling teeth 130, tuning fork like, includes a root 210 that stretches outward into two teeth 220, and the root 210 is disposed at the bottom of the cooling fins 130, and coupled to the rotary engine housing 120 The root 210 and the rotary engine housing 120 can be integrally formed as a whole, or connected to each other as an assembly. The heat generated from the combustion of the engine conducts through the root 210 on the housing to the fins 220.
The two-tooth fins 220 enlarge the exposed surface area for dissipating the heat effectively, so that different outward stretching fin teeth such as a three, or a four is included in the present invention. In this preferred embodiment, the two-tooth fin is used to improve the heat dissipation efficiency. The length ratio of the fin tooth 220 to the root 210 will be ranged from 1 to 3.
In this preferred embodiment, the length ratio of the root 210 to the fin tooth 220 is approximately 1:2. In other words, the root length takes one third of the total length, from the bottom of the root to the fin tip. In this preferred embodiment, the thickness of the cooling fin 130 ranges from 1 mm to 3 mm, and the length from 5 cm to 10 cm, but the invention is not limited to such ranges only.
The cooling teeth 130 are radially, to the crank shaft center, stretched outward from the root 210 and distributed circumferentially along the engine housing, so the gap at the bottom of the cooling fin 130 is narrower than that at the tip of the cooling fin 130.
The heat distribution of the rotary engine 100 is not uniform. For instance, higher temperature appears at the ignition location of the rotary engine 100, and lower temperature, around the intake port of the rotary engine 100. If the cooling teeth 130 of the rotary engine 100 are equal spaced on the rotary engine, then the fins at high temperature zone close to ignition location will be insufficient or the fins at low temperature zone close to the intake port will be more than necessary and increase the overall weight. In this preferred embodiment, the cooling teeth 130 are distributed with different densities based on the heat load distribution. Therefore, the cooling fins at high heat zone, between ignition location and the exhaust port, takes high density distribution to offer sufficient exposed surface area for heat dissipation. The cooling fins at the low temperature zone, between the intake port to the ignition location, takes low density distribution or no fins required there in order not to have an excess weight.
With reference to
With reference to
In this preferred embodiment of the present invention in
With reference to
The two-tooth fins 620 enlarge the exposed surface area for dissipating the heat effectively at the tip, so that different outward stretching fin teeth such as a three, a four or a branch-shaped is included in the present invention. In this preferred embodiment, the two-tooth fin is used to improve the heat dissipation efficiency. The length ratio of the fin tooth 620 to the root 610 will be ranged from 1 to 3.
In this preferred embodiment, the length ratio of the root 610 to the fin tooth 620 is approximately 1:2. In other words, the root length takes one third of the total length, from the bottom of the root to the fin tip. In this preferred embodiment, the thickness of the cooling fin 430 ranges from 1 mm to 3 mm, and the length from 5 cm to 10 cm, but the invention is not limited to such ranges only.
The cooling teeth 430 are radially, to the crank shaft center, stretched outward from the root 610 and distributed circumferentially along the rotor housing or with a tilt angle to the root surface, so the gap at the bottom of the cooling fin 430 would be close to the gap at the tip.
The heat distribution of the rotary engine 400 is not uniform. For instance, higher temperature appears at the ignition location of the rotary engine 400, and lower temperature, around the intake port of the rotary engine 400. If the cooling teeth 430 of the rotary engine 400 are equal spaced on the rotary engine, then the fins at high temperature zone close to ignition location will be insufficient or the fins at low temperature zone close to the intake port will be more than necessary and increase the overall weight. In this preferred embodiment, the cooling teeth 130 are distributed with different densities based on the heat load distribution. Therefore, the cooling fins at high heat zone, between ignition location and the exhaust port, takes high density distribution to offer sufficient exposed surface area for heat dissipation. The cooling fins at the low temperature zone, between the intake port to the ignition location, takes low density distribution or no fins required there in order not to have an excess weight as shown in
The specific cooling fins in the present invention offer a high air cooling efficiency by increasing the exposed surface area. With its simplicity in function and no other auxiliary devices required, the cooling fins of the present invention effectively fit to a compact engine compartment such as a light sport aircraft. To enhance heat dissipation efficiency, continuous fin design and testing are required in sizes, shapes, and density alignments to secure a stable rotary engine operation. The external cooling fins in the present invention are typically used in a rotary engine to achieve a better heat dissipation efficiency for a more stable engine operation.
While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.
