1. Field of the Invention
This invention relates to internal combustion engines, especially an olive-shaped rotary engine.
2. Description of Related Art
Currently piston reciprocating engines are commonly used in automobiles. A piston reciprocating engine drives a piston's reciprocating and rectilinear motion by combusting in a combustion chamber. Then the piston's reciprocating motion is converted to a crankshaft's rotary motion through a connecting rod and the crankshaft, thus driving gearing's output. The piston reciprocating engines have large reciprocating inertia, complex structure and large volume. To solve these problems, Wankel, a German engineer, invented the rotary internal combustion engine in 1950s. The rotary internal combustion engine can directly convert the heat energy that is given off after the combustion and expansion of the fuel and air to the mechanical energy that drives the rotation of the rotor. Then the rotor drives the principal shaft to put out energy. As it cancels the rectilinear motion, the rotary internal combustion engine of the same power has simpler structure, smaller volume, lighter weight, and lower vibration and noise. Even though it has many advantages, the rotary internal combustion engine is not widely used because the shape of its combustion chamber can't make the fuel fully combust. Besides, the path of the flame propagation is long, increasing the loss of the fuel oil. In addition, the rotary internal combustion engine can only be ignited by spark ignition and can't be ignited by compression ignition, so it can't use diesel fuel. Furthermore, the rotary internal combustion engine has small output torque and its structure has high requirements for the lubrication of the engine, cooling and sealing. Therefore it has high manufacturing process requirements. Because of these reasons, the rotary internal combustion engine can't be widely used.
This invention aims at overcoming the above defects the existing piston engine and rotary internal combustion engine have, and providing a new-type olive-shaped rotary engine. The olive-shaped rotary engine is of simple structure, small volume and light weight. In addition, it operates stably, reduces vibration, improves output torque and makes fuel fully combust. It can use a wide range of the available fuels and has minor mechanical wear.
This invention is realized by the following technical solutions. The olive-shaped rotary engine comprises a crankshaft, a shell and a triangle rotor. The shell mould cavity is olive-shaped and both ends are covered with end caps. The triangle rotor is placed in the olive-shaped mould cavity. The mould cavity curve and hollows of the triangle rotor are of the same breadth, and the shaft line of the principal shaft of the crankshaft is coincident with the center of the mould cavity. The rotor is connected with the crankshaft through a connecting handle. The cylinder on the connecting handle is the rotor's connecting shaft, which is placed at the center hole of the triangle rotor. Its shaft line is coincident with the center line of the rotor. The rotor's connecting shaft is sleeved on a crankpin through its eccentric orifice. The connector on one side of the rotor's connecting shaft is equipped with a gear set, which is used to control the rotation of the connecting handle. The crankshaft rotates when the gear set drives the connecting handle to rotate, thus making the moving path of the center of the rotor's connecting shaft a shuttle-like path.
Assume the crank radius of the crankshaft is R. Then the distance between the rotor's connecting shaft and the shaft line of the crankpin is √{square root over (3)} R, and the shuttle-like moving path is an arc line crossed by two circles with the distance from their centers of 2√{square root over (3)}(13+√{square root over (3)})R and a radius of 2(1+√{square root over (3)})R.
Assume an outer corner between a connecting line that connects the center of the crankpin with the center of the principal shaft of the crankshaft and the major shaft of the shell is α. And the outer corner between a connecting line that connects the center of the rotor's connecting shaft with the center of the crankpin and a connecting line that connects the center of the crankpin with the center of the principal shaft of the crankshaft is β. The relationship of the two angles is:
When 0°≦α≦180°, tan(β/2)=0.5×tan(90−α)×{(3−√{square root over (3)})+√{square root over ((2−√{square root over (3)})×[2+4/(1+sin α)])}}
When 180°≦α≦360°, tan(β/2)=0.5×tan(90−α)×{(3−√{square root over (3)})+√{square root over ((2−√{square root over (3)})×[2+4/(1−sin α)])}}
The gear set in this invention comprises the following gears. A connecting handle's gear is fixed on the connector on one side of the rotor's connecting shaft. This gear is sleeved on the crankpin and is coaxial with the crankpin. Another gear is fixed on the shell. The gear is sleeved on the principal shaft of the crankshaft. Its center is coincident with the rotation center of the crankshaft. The rotary shaft of two coaxial idle pulleys is placed on the gear carrier of the crankshaft and is meshed with the shell's fixed gear and the connecting handle's gear respectively.
According to the above relationship of angles and the transmission gear ratio between the gears meshed with each other in the gear set, the crankshaft is reverse rotary with the connecting handle and the transmission gear ratio between the connecting handle and the crankshaft is:
Because the cycle of α is 180°, when 180°≦α≦360°, it's acceptable to substitute α−180°.
Two sets of air inlets and air outlets are placed on the shell, symmetrically on the hollows near two top ends of the olive-shaped mould cavity, of which the air inlet is close to the olive-shaped top end. A combustion chamber is placed at the air outlet or air inlet. The shape of the combustion chamber depends on the mode of the combustion. The compression ratio of the engine depends on the volume of the combustion chamber. According to the requirements of different fuels, the sides are equipped with either spark plug or oil sprayer. The internal surface of the olive-shaped shell is equipped with air press channel which is close to the combustion chamber, The air press channel can be single-channel or multi-channels, The air press chambers which are formed when the rotor is rotating is connected with the combustion chamber through the air press channel. Grooves are placed respectively in the middle of two cambered surfaces of the olive-shaped shell, and a sealing strip is placed in each of the grooves. The sealing strip clings to the rotor through a leaf spring in the groove. The surface of the sealing strip facing the triangle rotor is double hollows which are applicable to the arc curve of the rotor with the larger radius and the arc curve of the rotor with the smaller radius respectively. Both ends of the rotor are covered with triangle arc sealing strips. They are placed in the groove near the end's edge of the rotor. The leaf spring is placed in the groove to make the sealing strips cling to the end cap of the shell. The side of the end cap facing the rotor can be inserted with ceramic plates, which can reduce the heat loss when the rotor rotates because of its good thermo insulating property. A balancing plate is fixed on the connecting handle and it's used to balance the rotor's engine.
The cambered surface of the triangle rotor is a closed camber line, which is formed by three 60° arcs with a larger radius being crossed with three 60° arcs with a smaller radius. The mould cavity of the olive-shaped shell is a closed camber line, which is formed by two 120° arcs with a larger radius being crossed with two 120° arcs with smaller radius. The smaller radius is r=(0.5˜3) R, and the larger radius is R′=2(3+√{square root over (3)})R+r.
The invention has the following advantages. This engine is of small volume, light weight, large output torque under the same working volume, good accelerating ability and low working noise. Compared with piston reciprocating engines, it's of simpler structure, less operating parts and more stable operation. Compared with the existing triangle rotary internal combustion engines, the shape of the combustion chamber according to the present invention can make the fuel fully combust and use diesel oil as the fuel. In addition, when the explosive power is at its maximum, there's generally no torque output for piston reciprocating engines and rotary internal combustion engines; but there's torque output for the engines according to the present invention. Compared with the existing engines, the torque output maximum has been greatly improved. The rotating speed of the crankshaft according to the present invention is slower than that of the triangle rotary internal combustion engines, so it can not only reduce the loss of the engine's parts but also reduce the requirements for lubrication and sealing. All in all, whether it's under a high rotating speed or under a low rotating speed, the torque output of the engine according to the present invention is larger. It overcomes the defect of smaller torque output when the triangle rotary internal combustion engine operates under a low rotating speed, thus reducing the consumption of the fuels.
An embodiment of the invention is a birotary engine. The birotary engine has compact structure and stable operation, being equivalent to piston reciprocating four cylinder engine. The structure of its crankshaft is shown in
As is shown in the drawings, the crankshaft 3 is placed at the center of the mould cavity of the olive-shaped shell, that is, its shaft line is coincident with the center line of the mould cavity. The connecting handle 4 is the connector between the rotor 2 and the crankshaft 3. Its cylinder is the rotor's connecting shaft 41, which is placed in the center hole of the rotor 2. Its shaft line is coincident with the center line of the rotor. The rotor's connecting shaft 41 is sleeved on a crankpin 32 through its eccentric orifice. Assume the radius of the crankshaft is R. The eccentric orifice between the rotor's connecting shaft 41 and the shaft line of the crankpin 32 is √{square root over (3)} R. A connector 42 on one side of the rotor's connecting shaft 41 is equipped with the gear set, which is the driving mechanism used to control the rotation of the connecting handle 4. When the principal shaft 31 of the crankshaft rotates, the gear set drives the connecting handle 4 to rotate, making the shaft line of the rotor's connecting shaft 41 of the connecting handle 4 move along a shuttle-like moving path, that is, the shuttle-like moving path is the arc line crossed by two circles with the distance between their centers of 2√{square root over (3)}(1+√{square root over (3)})R and a radius of 2(1+√{square root over (3)})R, as shown in
The above gear set comprises the following four gears: a gear fixed on the connecting handle 4, that is, the connecting handle's gear 51 which is sleeved on the crankpin 32 and is coaxial with the crankpin 32; a gear fixed on the shell 1, that is, the shell's fixed gear 54 which is sleeved on the principal shaft 31 of the crankshaft and is coaxial with the principal shaft 31 of the crankshaft; and coaxial idle pulleys 52 and 53 meshed with the connecting handle's gear 51 and the shell's fixed gear 54 respectively and with their rotary shaft 55 placed on the gear carrier 56. The shell's fixed gear 54 and the idle pulley 53 are common circular gear and have a transmission ratio of 2; and the idle pulley 52 and the connecting handle's gear 51 are gears with special shape and have the following transmission ratio:
As shown in
When 0°≦α≦180°, tan(β/2)=0.5×tan(90−α)×{(3−√{square root over (3)})+√{square root over ((2−√{square root over (3)})×[2+4/(1+sin α)])}}
When 180°≦α≦360°, tan(β/2)=0.5×tan(90−α)×{(3−√{square root over (3)})+√{square root over ((2−√{square root over (3)})×[2+4/(1−sin α)])}}
According to the above relationship of the angles, the crankshaft 3 is reverse rotary with the connecting handle 4. According to the transmission ratio of the gear set, the rotating speed of the connecting handle 4=the rotating speed of the crankshaft 3×
When 0°≦α≦180°, the above formula is applicable; when 180°≦α≦360°, it's acceptable to substitute α−180°. According to the above formula, the rotating speed of the connecting handle 4 is about twice of the rotating speed of the crankshaft 3.
As shown in
As shown in
The triangle rotor 2 divides the shell 1 into two working chambers, every working chamber is equipped with air inlet 11 and air outlet 12. The air inlet 11 and the air outlet 12 are close to top ends of olive-shaped shell, and the air outlet 12 is equipped with the combustion chamber 13. The internal surface which is close to the combustion chamber 13 is equipped with groove which is used as the air press channel 14. When the rotor rotates and compresses, the air pressing chamber is formed in the inner chamber of the shell, the air in the air press chamber is compressed into the air press channel 14, and entered into the combustion chamber 13. According to the different kind of the fuels, the combustion mode can be swirl combustion, turbulent flow combustion, or mixed combustion. The combustion chamber which is used for the swirl combustion is single or double swirl chamber. As is shown by
The balancing of this engine comprises two parts. First, this engine is a birotary engine. As shown in
The sealing of the triangle rotors includes cambered surface seal and the end face seal. The cambered surface seal is shown in
The cooling system of this engine is shown in
When the rotor 2 rotates in the olive-shaped shell 1, it should be lubricated in order to reduce the friction between the external surface of the rotor 1 and the cambered surface of the mould cavity and the end cap 17 of the shell. The lubrication includes rotor cambered surface lubrication and rotor end lubrication. The rotor cambered surface lubrication is shown in
When the triangle rotor 2 rotates in the shell 1, it divides the space in the shell 1 into two parts, thus forming an upper working chamber and a lower working chamber. With the continual rotation of the rotor 2, the volumes of the two working chambers are changed continually. Two sets of air inlets 11, air outlets 12 and the combustion chamber 13 are placed on the hollows of the two ends of the olive-shaped shell 1. When a valve mechanism 9 controls the valve, the air inlet and air outlet are opened and closed, and the basic working process of the internal combustion engine is realized in the two working chambers respectively. The working process of the rotary engine is as follows. Firstly as shown in
The air outlet 12 in the figures is close to the olive-shaped shell's end. Besides, the location of the air inlet 11 and the air outlet 12 can be exchanged, i.e., placing the air inlet 11 close to the olive-shaped shell's end. When the air inlet 11 is close to the olive-shaped shell's end and the combustion chamber is at the bottom of the air outlet, the performance of the engine is better.
The gear set mentioned in this invention can be realized by installing externally tangent gears and other gear structure. The transmission ratio is not limited to the numbers in the embodiments. As long as they are of the same effect, they are acceptable. In addition, this engine can be configured as multiple rotary engines connected in series, thus making the output of the engine more stable.
Number | Date | Country | Kind |
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200810015978.X | May 2008 | CN | national |
The present application claims the benefit of International Application No. PCT/CN2009/000477, for which this application hereby enters the U.S. National Stage under 35 USC 371.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CN09/00477 | 4/30/2009 | WO | 00 | 1/24/2011 |