Engine

The invention involves an engine that the cylinder block contains a coupled piston formed by a main piston, an external piston. The external piston is sleeved outside of the main piston and uses the rods on the two sides to connect to the heart-shape groove on the two sides of the crankshaft inside the crankcase at the bottom of the cylinder block. It moves with the main piston in an upward stroke and in a downward stroke. It forms a direct fuel injection device in the cylinder without carburetor. It does not need to add lubricants in the fuels. Besides, the engine has increased compression ratio.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to the structure of a two-stroke internal combustion engine. Especially, it involves a type of engine that converts the instant power of fuel into cyclic linear movement of an external piston.

2. Description of the Prior Art

Current internal combustion engines (engine) are mainly two-stroke or four-stroke. Please refer toFIG. 1for the structure for a common two-stroke engine. Its cylinder block10has an air intake11and an air exhaust12on two opposite sides. A piston13has a sealing piston ring14inside the cylinder block10. One end of a connecting rod15connects to a piston pin16inside the piston13. The other end of the connecting rod15connects to a crankshaft18inside a crankcase17at the bottom of a cylinder block10. When the piston13is in an upward stroke at the top of cylinder block10to compress the mixed fuels, a spark plug19ignites the fuels to explode and force the piston13in a downward stroke. Then through the crankshaft18, the power is output. When the piston13is below the air exhaust12in a downward stroke, the combustion waste gases are exhausted. Upon exhausting the waste gases, the air exhaust12experiences a Venturi effect that builds up pressure in the crankcase, so the pressure in the top of the cylinder block10becomes negative. The air intake11(with check valve) sucks in mixed fuel gases. At this moment, the piston13uses the rotational power from the connecting rod15and the crankshaft18to generate an upward stroke and compress the mixed fuel gases again and ignite to explode. From the description above, it is known that the two-stroke engine has advantages in simple structure, low power loss and high power output. Since the piston13passes by the air intake11and the air exhaust12on two opposite sides of the cylinder block10in an upward stroke and a downward stroke, the crankcase17cannot store engine oils inside. But because mechanical movement needs lubrication, the two-stroke engine needs lubricants in its fuels. Thus, combustion causes lubricant film formations and the combustion is apparently incomplete. This leads to emission of polluting waste gases that cause environmental issues. The objective of the invention is to provide for a two-stroke engine to minimize pollution from emission of waste gases and increase its power output.

SUMMARY OF THE INVENTION

Therefore, the main objective of the invention is to provide a two-stroke engine that places an external piston on the main piston. The external piston uses two side connecting rods to connect to the two sides of the crankshaft in a heart-shape groove and is able to move with the main piston in an upward stroke and a downward stroke, so the explosive power from combustion is converted to cyclic linear motion. This is to replace the complicated air valve structure in a four-stroke engine. The invention also adds blocking rings to the skirt section of the external piston and the main piston. This design and the pre-compression single-stream airway inside the crankcase can provide lubrication as four-stroke engine does and remove the restriction that two-stroke engine has to add lubricants to its fuels.

Another objective for the invention is for the external piston to close the air intake valve and the air exhaust valve early and block the leaking of the mixed fuel gases in the cylinder by angular variation of the heart-shape grooves on the two opposite sides of the crankshaft, and also to increase gas intake capacity for the cylinder and the compression ratio to add power.

Another objective for the invention is to provide an engine with an oil supply system that uses the oil pump driven by the heart-shape grooves on the two sides of the crankshaft to lubricate mechanical parts and replace carburetors. It pumps out fixed amount of oils in standard mixing ratio and prevents backflow of oils by a check valve. Through one-way pressure-regulating valve, the fuel enters in one way. Fuel supply is adjustable and a stable amount of fuel is directly injected to the cylinder to overcome the shortcoming of traditional carburetors and electronic fuel injectors.

Another objective of the invention is to provide an engine that the 1st stage cylinder bore of the external piston and cylinder block has waving edges, so when the external piston and the cylinder block contact each other, there is waving contact surface and the main piston and the external piston move at the same time. The piston ring of the main piston can enter or leave smoothly the chamber of the external piston without jamming up the groove.

To realize the above objective, the invention provides an engine that its cylinder block has coupled piston comprising a main piston and an external piston. The mentioned external piston encloses the main piston and uses two sides connecting rods to connect to the two sides of the crankshaft in a heart-shape groove inside the crankcase at the bottom of the cylinder block, so it moves along with the main piston in an upward stroke and a downward stroke.

It is preferred that the skirt section for the main piston or the external piston for the coupled piston has blocking rings to prevent lubricants from leaking through air intake and air exhaust.

It is more preferred that the heart-shape grooves at the two sides of the crankshaft driving the external piston in an upward stroke and a downward stroke are formed by connection of large and small circular grooves.

It is also more preferred that the heart-shape grooves at the two sides of the crankshaft are concave, convex or combination of both as toothed wheels.

It is also more preferred that the cylinder bore is two sections in the cylinder block, and has two different inner diameters.

It is also more preferred that that the crankcase at the bottom of the cylinder block passes to a single-stream independent airway and controls the direction of gas flow through the airway.

It is also more preferred that the gases inside the crankcase at the bottom of the cylinder block enter the cylinder through a single-stream independent airway or leave the crankcase before re-entering the cylinder.

It is also more preferred that the cylinder has a direct fuel injection system composed of an oil pump, a check valve and a regulating valve. The power for oil supply system is generated by the rotation of heart-shape grooves on two sides of the crankshaft inside the crankcase at the bottom of the cylinder block.

It is also more preferred that the contact surface of the external piston and the first section of the cylinder are waving.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

To further explain the objective, features and benefits of the invention, a preferred embodiment is described as follows:

Please refer toFIG. 2toFIG. 8. The structure for the engine in the invention mainly uses a coupled piston structure consisting of a main piston20and an external piston30inside a cylinder block10. When the coupled piston moves inside the cylinder block10in an upward stroke and a downward stroke, the external piston30can open or close the air intake11and the air exhaust12on the two opposite sides of the cylinder block10. This prevents the lubricants171stored inside the crankcase17from leaking out. Thus, the invention utilizes the lubrication concept of four-stroke engine to overcome the restriction of a two-stroke engine of having to add lubricants in the fuels, to improve the emission of waste gases. The features for the invention are as inFIG. 8that shows the main piston20has a sealing piston ring21at top and a sealing blocking ring22at a skirt; the external piston30has a chamber31passing through its interior, a sealing piston ring32at top, a sealing blocking ring33at a skirt; the main piston20is able to move up and down inside the chamber31of the external piston30; one end of a connecting rod15connects to a piston pin16and also links to the main piston20while the other end connects to the crankshaft18inside the crankcase17at the bottom of the cylinder block10; a rod seat34at the two opposite sides of the bottom end of the skirt of the external piston30is for connection of one end of the rod35while the other end connects to a guide pulley36, so the rod35uses the guide pulley36to lie against the heart-shaped grooves on the two sides of the crankshaft18and is thus driven to move the external piston30in a upward stroke and a downward stroke; the heart-shaped groove is ring shaped grooves on the two sides of the crankshaft18, concave or convex or a combination of both as toothed wheel, with one half as large circular groove41coaxial with the crankshaft18and the other half forms two small circular groove42A and42B non-coaxial with the crankshaft18; a groove low point43is formed and near the center of crankshaft18between openings of the two small circular grooves42A and42B; the interior of cylinder block10has two sections, the 1 st stage cylinder bore10A equivalent to the outside diameter of the main piston20, the 2nd stage cylinder bore10B equivalent to the outside diameter of the external piston30, while the air intake11and the air exhaust12on the two opposite sides of the cylinder block10are located on the 2nd stage cylinder bore10B; as shown inFIG. 2,FIG. 6andFIG. 7at this location the crankshaft18uses the connecting rod15to push the main piston20up to inside the 1st stage cylinder bore10A of the cylinder block10, and the main piston20uses its top piston ring21to seal the compressed mixed fuel gases, and the heart-shape grooves on the two sides of the crankshaft18use the large circular groove41to push against the guide pulley36of the rod35and allow the external piston30to remain at the top of the 2nd stage cylinder bore10B of the cylinder block10, and the piston ring32and the blocking ring33at the top and the skirt are around the position of the air intake and the air exhaust11,12to stop the lubricants inside the crankcase17from leaking through the air intake and the air exhaust11,12; as shown inFIG. 3at this position, the spark plug19ignites the compressed mixed fuel gases and pushes the main piston20in a downward stroke into the chamber31of the external piston30, and the downward main piston20uses the connecting rod15to push the crankshaft18counterclockwise 90 degrees, and the rods35at the two sides of the external piston30still have their guide pulley36inside the heart-shape large circular groove41, so the rods35do not move with the main piston20and are still at the position to seal the air intake and the air exhaust11,12; as shown inFIG. 4at this position the main piston20continues its downward stroke and uses the connecting rod15to push the crankshaft18counterclockwise to 180 degrees, and at the same time the guide pulley36on the rods35on the two sides of the external piston30enters from one small circular groove42B into the heart-shape groove low point43, and the rod35can pull the external piston30and moves together with the main piston20downward to open the air intake and the air exhaust11,12; as shown inFIG. 5at this position the crankshaft18continues to rotate counterclockwise to about 270 degrees and pushes the main piston20and the external piston30together upward to the top point of the 2nd stage cylinder bore10B of the cylinder block10, and the external piston30seals the air intake and the air exhaust11,12again until it gets back to the position shown inFIG. 2, and the crankshaft18completes a full cycle (360 degrees) and drives the main piston20upward again to compress the mixed fuel gases; in summary, the coupled piston composed of the main piston20and the external piston30is to prevent the leaking of lubricants171inside the crankcase17from leaking through the air intake and the air exhaust11,12, and a four-stroke engine concept is used to solve the emission pollution issue for two-stroke engine that had to add lubricants to the fuels; further, through the angular variation of the large circular grooves41on the two sides of the crankshaft18and the two small circular grooves42A,42B, the external piston30can close out in an early time the air intake and air exhaust11,12on the two opposite sides of the cylinder block10to prevent the leaking of the mixed fuel gases inside the cylinder block10, and the external piston30can also increase air intake to raise up the compression ratio and the power output as well.

Please refer toFIG. 9andFIG. 10. They are the illustrations for gas flow in the different sections of the single-way independent airway for the invention. The inlet of the single-flow independent airway50has throttle valve51and the first check valve52, and the second check valve53on the way to the crankcase17, the third check valve54on the same way to the airway50, and the end of the independent airway50connects to the air intake11for the cylinder block10, and a fuel injector55or a carburetor56is in the middle; thus, the independent airway50capacity is determined by the air intake volume due to the upward stroke of the main piston20and the external piston30inside the cylinder block10to the top point of the crankcase17, as shown inFIG. 9. When the main piston20and the external piston30move upward to the top point (compression, ignition), an equal amount of air intake from the crankcase17lowers the air pressure inside the crankcase17and opens up the second check valve53to allow outside air going to the airway50(indicated by X); as shown inFIG. 10, when the main piston20and the external piston30move downward to the bottom point (explosion, exhaust) of the cylinder block10, they compress the air inside the crankcase17and close the first check valve52and the second check valve53, and open the third check valve54, and press the mixed lubricated fuel gases (indicated by 0) inside the crankcase17into the independent airway50and push the outside air (indicated by X) already inside the independent airway50through the fuel injector55or the carburetor56and the air intake11to the cylinder block10; in this way, the invention uses the first check valve52, the second check valve53and the third check valve54to control the single-way flow in the airway, and allow the outside air (indicated by X) and the crankcase17fuel gases (indicated by O) to enter in sequence, and as a result the fuel gases (indicated by O) inside the crankcase17always circulate in the independent airway50and the crankcase17, and after the outside air (indicated by X) enters the independent airway50, it does not enter the crankcase17, instead, is pushed through the fuel injector55or the carburetor56and the air intake11to the inside of the cylinder block10.

Please refer toFIG. 11for the coupled piston and the direct fuel injection system in the invention. The oil supply system consists of an oil pump60, a check valve62, one-way regulating valve63and the fuel lines61in the middle. The oil pump60is driven by the rotation of the heart-shape grooves on the two sides of the crankshaft18and the standard mixed fuel is sucked through fuel feed lines631and the one-way regulating valve63into the oil pump60. After pressurization of the oil pump60, the fuel is injected by the check valve62and the fuel injector55into the cylinder block10. The valve body621of the check valve62is subject to push by the rear spring622to close the valve port623and stop the backflow of the fuel inside the fuel injector55. Please refer to A-A Figure. The four sides of the valve body621are four flat surfaces. When the oil pump60pumps a certain quantity of fuel to push the valve body621backward to open the valve port623, the fuel can pass through the clearance624among four flat sides and flow to the fuel injector55through the check valve62; the one-way regulating valve63has a regulating screw636in the front end, a fuel feed line631on its side, a fuel line61connecting to an oil pump60in the back, and a valve rod632penetrating inside the valve body633. The valve rod632and the valve body633have four flat surfaces on four sides. Pressurized gasoline through the fuel feed line631enters the one-way regulating valve63and flows between clearance634between flat surfaces on the four sides of the valve rod632to push the valve rod632forward and open, so the fuel flows into the fuel line61in one way. When the oil pump60pumps the fuel in the fuel line61into the check valve62, if pressure is built up, it can push back the valve body623of the one-way regulating valve63and the valve rod632backward. This allows the pressurized fuel to flow back to the inside of the one-way regulating valve63through the flat clearance635on the four sides of the valve body633, then flow back to the fuel tank through the fuel feed line631. Thus, it enables the fuel injector55injects the fuels to the cylinder block10stably and directly.

Please refer toFIG. 12. The invention uses a coupled piston that moves simultaneously and is added a lubricating oil pump. The oil pump system includes an oil pump70and its fuel feeding check valve port71, fuel discharge check valve port72. The oil pump70is driven by the rotating heart-shape groove on the two sides of the crankshaft18or the rod35of the external piston30.

Please refer toFIG. 13andFIG. 14for the structure of the joint of the external piston and the cylinder block and its relation with the piston ring of the main piston. The top of the chamber31for the external piston30has waving flange80. The bottom of the 1 st stage cylinder bore10A for the cylinder block10has corresponding waving flange81. When the external piston30is located at the top of the 2ndstage cylinder bore10B for the cylinder block10. The waving flange80at the top of the chamber31is inserted into the waving flange81at the bottom of the 1st stage cylinder bore10A. In this way, it forms waving joint (as shown inFIG. 14). When the main piston20is in the same upward and downward strokes with the external piston30in the chamber31, when the piston ring21passes the interface of the external piston30and the 1st stage cylinder bore10A, it passes smoothly, so the piston ring21for the main piston20will not be stuck in the groove.

In summary, the invention improves the emission for a two-stroke engine without the complicated structure of valves in a four-stroke engine, and also increases air intake for the cylinder and its compression ratio to boost the power output. Besides, it also has the advantage of using the direct fuel injection system without carburetor.

Description of Main Components