Guiding scavenging valve mechanism of engine

Abstract

The invention provides an engine guiding scavenging valve mechanism which solves the problem that a traditional overhead valve type engine valve mechanism is difficult to efficiently sweep waste gas in a two-stroke working mode. According to the technical scheme, the air inlet valve air distribution assembly of the engine guiding scavenging air distribution machine comprises an air inlet valve rod arranged in an air inlet channel, the rear portion of the air inlet valve rod is connected with an air inlet valve cam and an air inlet valve spring pushing air inlet valve opening and closing air inlet, and the air inlet valve rod is provided with an air guide pipe which moves along with the air inlet valve rod through a support sleeve and is close to the head of an air inlet valve. A front-end air outlet is reserved between the front end of the air guide pipe and the air inlet valve head, and a rear port of the air guide pipe communicates with the air inlet channel. By conducting guiding scavenging on inlet air and exhausting waste gas, the double-stroke-type engine can be suitable for a double-stroke-type working engine, an independent lubricating system is formed, a crankshaft rotates by a circle to complete one-time acting, by conducting guiding scavenging on the inlet air, the combustion efficiency and the emission performance are improved, the scavenging efficiency is greatly improved, and then the working efficiency of the engine is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of internal combustion engines, and particularly to an engine guided scavenging valve train, which is applicable to an overhead valve two-stroke engine. Background Art

[0002] Internal combustion engines have a history of more than 150 years since their invention. According to the working cycle mode, they are mainly divided into two-stroke engines and four-stroke engines. Traditional two-stroke engines use a side-mounted valve intake and exhaust hybrid lubrication. The crankshaft rotates one week to complete one power stroke, and the intake, compression, power stroke, and exhaust processes are completed through two strokes of the piston. The exhaust gas is pushed out by the new mixture. Limited by its structure, valve train, and scavenging process, there is a lot of exhaust gas residue, and the unburned oil is discharged with the exhaust gas, resulting in problems such as low combustion efficiency, poor emission performance, serious exhaust gas pollution, and high fuel consumption. The valve train is an important component of the engine. Four-stroke engines usually use an overhead valve train, including a valve group and a valve drive group arranged on the cylinder head of the cylinder block. The valve group includes an intake valve and an exhaust valve. The intake and exhaust valves mainly include an intake valve stem and a valve head. The valve drive group mainly includes an intake valve stem, a valve head, a cam mechanism for driving and pushing the valve to expand and contract, and a valve spring. The working mode of a four-stroke engine is that the crankshaft rotates two weeks to complete one power stroke, and the intake, compression, power stroke, and exhaust processes are completed through four strokes of the piston. Although it solves the exhaust emission problem through separate lubrication, its working mode has obvious drawbacks. The engine crankshaft needs to rotate two circles to do one power stroke, and the valve train needs to cooperate with the crankshaft to complete the four processes of intake, compression, power stroke, and exhaust. During this period, a large amount of stroke loss and unnecessary mechanical wear are generated, and additional energy and time are consumed, resulting in fuel waste and mechanical loss. In addition, due to the long working time cycle, the engine is large in size and the manufacturing cost increases. Therefore, it is urgent to develop a new engine structure and valve design to solve the above technical problems.

[0003] The patent document with the publication number CN107420195B provides a two-stroke engine based on the structure of a four-stroke engine. The improved structure of its valve train is to set a longitudinally arranged intake pipe and a longitudinally arranged streamlined intake valve head. A narrow throat is set in the valve seat ring in the intake pipe, and the sealing part of the intake valve head is below the valve seat ring. During operation, the transmission ratio of the crankshaft to the intake camshaft and the exhaust camshaft is 1:1. Each time the piston completes a reciprocating motion in the cylinder, it drives the crank connecting rod mechanism to rotate one week, and drives the intake valve and the exhaust valve to open once each through the camshaft transmission mechanism, forming a two-stroke working cycle mode. When the intake valve opens, the exhaust valve also opens. Fresh gas enters the cylinder combustion chamber through the gap between the narrow throat of the intake pipe and the intake valve head. The streamlined surface of the intake valve head is used to guide the air flow to complete the scavenging process, increasing the effect of ejecting the exhaust gas after combustion in the cylinder. The intake valve always remains in the intake pipe. It has an improved effect on guiding the air flow compared with the traditional disc-shaped valve head, but its intake valve head is still at the intake pipe port. Moreover, due to the narrow throat set in the intake pipe, it greatly hinders the entry of fresh gas, reduces the gas flow rate, and greatly limits the function of guiding gas. Especially, it cannot extend into the piston cylinder interior and deeper areas to guide gas and scavenge exhaust gas. Therefore, this valve train is difficult to scavenge exhaust gas efficiently during the intake process and cannot further improve the combustion efficiency and emission performance. Summary of the Invention

[0004] The object of the present invention is to provide an engine guiding scavenging valve train, which solves the problem that the valve train of the traditional overhead valve engine is difficult to scavenge exhaust gas efficiently in the two-stroke working mode. It discharges exhaust gas through guiding scavenging of intake air, and improves the combustion efficiency and emission performance.

[0005] The technical solution adopted by the present invention is: the engine guiding scavenging valve train includes an overhead valve type intake valve train assembly and an exhaust valve train assembly arranged on the cylinder head of the cylinder block. The intake valve train assembly includes an intake valve rod with an intake valve head arranged in the intake passage. The rear part of the intake valve rod is connected with an intake valve cam and an intake valve spring to push the intake valve to open and close the intake port. The technical key point is that: the intake valve rod has a guide pipe sleeved through a bracket and moving along with the intake valve rod. The guide pipe is close to the intake valve head. There is a front end air outlet between the front end of the guide pipe and the intake valve head, and the rear end port of the guide pipe communicates with the intake passage.

[0006] The guide pipe and the straight section intake hole of the intake passage near the intake port are in clearance fit.

[0007] The bracket of the guide pipe is a connecting rod or a connecting rib plate arranged between the inner wall of the middle part of the guide pipe and the intake valve rod;

[0008] The bracket of the air duct includes a front bracket and a rear bracket respectively arranged at both ends of the air duct. The front bracket is a connecting rod or a connecting rib plate between the front end air outlet of the air duct and the intake valve stem or the intake valve head; the rear bracket is a connecting rod or a connecting rib plate between the rear end port of the air duct and the intake valve stem.

[0009] The front end air outlet of the air duct is arranged as an inclined port facing away from the exhaust valve.

[0010] A plurality of air outlet holes are provided on the wall of the air duct.

[0011] The advantages and beneficial effects of the present invention are as follows: Since the engine guiding scavenging valve train adopts an overhead valve train, and an air duct that moves with the intake valve stem is fixedly sleeved on the intake valve stem of the valve train, a front end air outlet is left between the front end of the air duct and the intake valve head. An intake cam convex portion that can push the intake valve head into the inner cavity of the cylinder can also be provided on the intake cam of the valve train. It is possible to control the air guiding area formed by the intake valve air duct extending into the inner cavity of the cylinder through the operation of the intake cam. Therefore, the fresh air entering the cylinder can be guided by the air duct and blown into the air guiding area, so as to reach deep into the cylinder to purge the exhaust gas after combustion, open the exhaust valve to work, and fully sweep the exhaust gas, avoiding the problem of low scavenging efficiency of the traditional intake valve that can only purge the exhaust gas at the valve port. Therefore, it is especially applicable to engines operating in the two-stroke cycle, forming an independent lubrication system and completing one power stroke in one revolution of the crankshaft. By guiding the intake air for scavenging, the combustion efficiency and emission performance are improved, the scavenging efficiency is greatly improved, and thus the engine working efficiency is improved. Description of the Drawings

[0012] The present invention will be further described below with reference to the drawings.

[0013] Figure 1 is a schematic structural diagram of the embodiment of the present invention installed on the engine; Figure 2 is a schematic structural diagram of the embodiment of the present invention; Figure 3 is a schematic diagram of the first intake valve structure of the embodiment of the present invention; Figure 4 is Figure 3 a schematic longitudinal sectional view structure diagram of Figure 5 is a schematic diagram of the second intake valve structure of the embodiment of the present invention; Figure 6 is a schematic diagram of the third intake valve structure of the embodiment of the present invention; Figure 7 is a schematic diagram of the fourth intake valve structure of the embodiment of the present invention; Figure 8 is a schematic diagram of the fifth intake valve structure of the embodiment of the present invention; Figure 9 It is a schematic structural diagram of the second working state of the embodiment of the present invention; Figure 10 It is a schematic structural diagram of the third working state of the embodiment of the present invention; Figure 11 It is a schematic structural diagram of the fourth working state of the embodiment of the present invention; Figure 12 It is a schematic structural diagram of the fifth working state of the embodiment of the present invention; Figure 13 It is a schematic structural diagram of the fifth intake valve working state of the embodiment of the present invention; Figure 14 It is a schematic diagram of the valve timing of the present invention.

[0014] Description of the numbers in the figure: 1 cylinder head, 2 intake passage, 3 intake valve, 4 cylinder block, 5 piston, 6 crankshaft, 7 crankcase, 8 intake valve cam, 9 intake valve spring, 10 exhaust valve cam, 11 exhaust valve spring, 12 exhaust valve, 13 exhaust port, 14 fuel injector, 15 air guiding area, 21 straight-section intake hole, 31 intake valve stem, 32 air duct, 33 intake valve head, 34 front end air outlet, 35 rear port, 36 bracket, 37 air outlet hole, 81 convex part. Detailed implementation manners

[0015] According to Figures 1-14 the present invention will be described in detail. The embodiments are as follows Figure 1 and Figure 2 shown, an engine directed scavenging valve train. The valve train includes an overhead valve type intake valve train assembly and an exhaust valve train assembly provided on the cylinder head 1 of the engine cylinder block. The intake valve train assembly includes an intake valve stem 31 with an intake valve head 33 provided in the intake passage 2. The rear part of the intake valve stem is connected with an intake valve cam 8 and an intake valve spring 9 to push the intake valve to open and close the intake port 13. The engine body group includes: cylinder block 4, cylinder head 1, crankcase 7, etc. The valve train adopts overhead valves. An intake valve 3 driven by the intake valve cam 8 and the intake valve spring 9 is provided on the cylinder head 1. A straight-section intake hole 21 communicating the intake passage 2 with the intake port is provided at the front part of the intake valve. The intake valve head 33 can block and open the intake port; the crankshaft 6 of the crankshaft connecting rod mechanism drives the synchronous rotation of the camshaft and the crankshaft through timing gears, chains or timing belts and operates in a two-stroke working mode. The improvement lies in: as Figures 1 to 3As shown, at the front part of the intake valve stem 31 of the valve train, an air guide pipe 32 is fixedly sleeved through a bracket 36. The air guide pipe is movably arranged in the straight-line intake hole 21 where the intake passage 2 communicates with the intake port. The air guide pipe can move along with the intake valve stem. A clearance fit can be formed between the inner wall of the straight-line intake hole 21 and the air guide pipe 32, which can reduce the loss of fresh air from the gap between them and also reduce or prevent contact between them, thus reducing the frictional resistance generated between the valve and the air guide pipe due to the up-and-down movement of the valve. As Figure 2 and Figure 3 shown, at the front end of the intake valve stem 31 of the intake valve, a disc-shaped intake valve head 33 is provided. A certain distance is left between the front end of the air guide pipe and the intake valve head to form a front-end air outlet 34. The rear port 35 of the air guide pipe communicates with the intake passage 2, so that the inner cavity of the air guide pipe forms a passage connecting the intake passage and the intake port. The intake cam 8 of the valve train can be provided with an intake cam convex part 81 that pushes the front end of the air guide pipe 32 of the intake valve into the inner cavity of the cylinder block 4. The intake cam 8 of the intake valve of this valve train has a larger convex part than the conventional intake cam. The diameter of the intake cam 8 and the length of the intake valve stem are both larger than those of the exhaust cam 10, and the intake valve spring 9 is thicker than the exhaust valve spring 11, so that the stroke of pushing the intake valve stem and the head is relatively long, and the intake valve head can be pushed into the upper part of the inner cavity of the cylinder block to the center position or the air guiding area 15 between the positions close to the bottom dead center of the piston. The intake cam 8 pushing the intake valve head into the inner cavity of the cylinder block can adopt that the length of the intake cam convex part matches the depth of the intake valve head extending into the cylinder block. Therefore, the fresh air entering the cylinder can be guided by the air guide pipe and blown into the air guiding area, achieving the purpose of deeply purging the exhaust gas in the cylinder block, which is different from the working mode of the intake valve of the traditional engine, where only the valve head is separated from the air port to form an open state. The intake passage of the engine is connected to the outlet pipe of the turbocharging system or the mechanical supercharging system (i.e., the Roots blower) externally connected to the engine, or can also be connected to the outlet pipes of the turbocharging system and the mechanical supercharging system at the same time. The purpose is to let the pressurized fresh air enter the combustion chamber of the engine through the air guide pipe of the intake valve.

[0016] As a further improvement, as Figure 3 shown, the bracket 36 of the air guide pipe 32 can adopt a connecting rod or a connecting rib plate between the inner wall of the air guide pipe in the middle of the air guide pipe and the intake valve stem 31, so that the air guide pipe is stably connected to the intake valve stem part. The connecting rib plate can adopt a longitudinal thin sheet shape, which can reduce the resistance to air. The air guide pipe and the bracket can be connected and fixed by welding or an integral structure with the intake valve stem.

[0017] As a further improvement, as Figure 3 and Figure 4As shown in the figure, the bracket 36 of the air duct 32 can adopt a structure including a front bracket and a rear bracket respectively arranged at both ends of the air duct. The front bracket is a connecting rod or a connecting rib plate between the front end air outlet 34 of the air duct and the intake valve stem 31, and the rear bracket is a connecting rod or a connecting rib plate between the rear end port 35 of the air duct and the intake valve stem 31. It can not only stably connect the air duct with the intake valve, but also reduce the blockage of the inner cavity channel of the air duct. As Figure 5 shown, the front bracket can also adopt a connecting rod or a connecting rib plate between the front end air outlet of the air duct and the valve head, which can increase the stability. The connecting rib plate can adopt a longitudinal thin sheet shape, which can reduce the resistance to air.

[0018] As a further improvement, as Figure 6 shown, the front end air outlet 34 of the air duct 32 can be set as an inclined port facing away from the exhaust valve. The air outlet at the lower part of the air duct is in an inclined state with the direction of the intake valve head, so that when the fresh gas is ejected from the front end air outlet, it faces the inner wall of the cylinder block away from the exhaust valve, and most of the gas entering the cylinder block is sprayed onto the cylinder wall and the top of the piston. The inner wall of the cylinder block and the top of the piston are used to rebound the gas to sweep the burned exhaust gas, and the burned exhaust gas is better excluded from the cylinder block, increasing the efficiency of sweeping the exhaust gas. In order to prevent the air duct of the intake valve from changing the blowing direction due to movement and rotation, the valve guide rod of the intake valve can be made elliptical, or a positioning pin for preventing rotation can be made on the valve guide rod and the air duct of the valve, or the rotation can be prevented by limiting through the intake guide rod hole of the cylinder head.

[0019] As a further improvement, as Figure 7 shown, a plurality of air outlet holes 37 can be arranged on the wall of the air duct 32, so that when the air duct extends into the cylinder block from the air inlet, gas can be continuously ejected to sweep out the exhaust gas.

[0020] Working method and principle: As Figure 1 、 Figures 9 to 13 shown, the power stroke, exhaust, intake, and compression processes of a two-stroke diesel engine with a valve are successively shown, as well as the working states at each time period. The engine of the present invention is a two-stroke engine, and the working mode of the valve train is different from that of a traditional engine. The four-stroke valve train of a traditional engine has the intake valve and the exhaust valve open and close once every two revolutions of the crankshaft, while the valve train of the present engine has the intake valve and the exhaust valve open and close once each when the crankshaft rotates one revolution.

[0021] The working process includes the following steps: Figure 1This is the initial working state, that is, at the start of the power stroke. The intake valve 3 and the exhaust valve 12 are both in the closed state. The piston 5 is close to the top dead center position. The raised portions of the intake valve cam 8 and the exhaust valve cam 10 rotate to a position away from the spring. Then the crankshaft drives the camshaft to rotate synchronously counterclockwise through the timing gear, chain or timing belt. During cyclic operation, this process is also the power stroke, pushing the piston to move downward from the top dead center. The intake valve cam 8, the exhaust valve cam 10 and the crankshaft 6 rotate clockwise.

[0022] As Figure 9 shown, the exhaust valve cam 10 is arranged to push the exhaust valve spring 11 to open the exhaust valve 12 in advance before the piston 5 moves to the bottom dead center, releasing the pressure in the combustion chamber. At this time, the intake valve remains closed; this allows the burned exhaust gas to be discharged from the exhaust port 13.

[0023] As Figure 10 shown, before the piston 5 continues to move to the bottom dead center, the intake valve cam 8 rotates to the state of opening the intake valve. At this time, the intake valve just opens, and fresh air begins to be sent into the cylinder block for the intake process.

[0024] As Figure 11 shown, this is the process of simultaneous intake and exhaust. The piston continues to move to the bottom dead center and then gradually moves upward after passing the bottom dead center. During this process, the intake valve cam 8 pushes the head of the intake valve 33 into the inner cavity of the cylinder block, so that the intake valve reaches the maximum opening depth. The intake duct extends into the cylinder block, and the fresh air entering the cylinder can be guided by the duct to be blown into the air guiding area 15, achieving the purpose of deeply sweeping the exhaust gas in the cylinder block, sending the supercharged fresh air to the bottom of the cylinder block and then discharging the burned exhaust gas out of the cylinder block. After reaching the maximum depth, it retracts upward, so that the movement process of the head of the intake valve does not interfere with the movement position of the piston; As Figure 12 shown, this is the compression process of the engine piston. After scavenging, the exhaust valve 12 closes in advance, and the duct of the intake valve 3 gradually retracts to close the intake valve; it is also possible to arrange for the exhaust valve and the intake valve to close simultaneously. This position is just the position where the piston finishes replacing the fresh air, and it is also the position where the intake valve and the exhaust valve are closed, and it is also the start of the compression stroke. The piston 7 begins to continue moving upward to compress the air. The piston continues to move upward to reach the top dead center, completing the compression stroke process.

[0025] As Figure 1As shown, when it reaches the initial working state position, the mixed gas is ignited to drive the piston to do work. The piston of the engine is near the top dead center. The fuel injector 14 works to inject atomized diesel into the combustion chamber. It is also possible to inject gasoline or other combustible gases into the engine cylinder after the intake valve and the exhaust valve are closed. A spark plug can be added to turn it into a gasoline engine, or the engine can burn natural gas, liquefied gas, etc. After completing a working cycle, the engine enters the next power stroke.

[0026] As Figure 13 As shown, it is a schematic structural diagram of the fifth working state of the intake valve of the embodiment of the present invention. The front end air outlet 34 of the air duct 32 of the intake valve 3 is an inclined port. The front end air outlet of the air duct extends into the upper part of the cylinder inner cavity to the air guiding area between near the bottom dead center of the piston for scavenging. The closer the front end air outlet of the air duct is to the bottom dead center position of the piston, the better the scavenging effect. It is optimal that the front end air outlet of the air duct extends into the air guiding area between near the bottom dead center of the piston and the center of the cylinder inner cavity (let the air duct be close to the piston top). A plurality of air holes 37 are provided on the wall of the air duct, so that part of the fresh gas is ejected from the front end air outlet towards the inner wall of the cylinder away from the exhaust valve, and the inner wall of the cylinder is used to rebound the gas to scavenge the exhaust gas, increasing the efficiency of scavenging the exhaust gas.

[0027] Figure 14 As shown, it is a schematic diagram of the valve timing of the present invention. Among them, the rotation directions of the crankshaft, the intake cam, and the exhaust cam rotate counterclockwise along the coordinate. a represents the angle range of the exhaust cam from opening to closing, b represents the angle range of the intake cam from opening to closing, c represents the stroke angle range of the piston crankshaft for doing work, and d represents the angle range of the piston crankshaft compression stroke. The intake valve can be opened at a position 28 degrees to 35 degrees before the piston reaches the bottom dead center. The exhaust valve can be opened at a position 30 degrees to 60 degrees before the intake valve opens. The intake valve can be closed simultaneously with the exhaust valve or can be closed with a certain delay angle. It can be adjusted by adjusting the angle range of the convex parts of the intake valve cam and the exhaust valve cam, reducing the intake stroke and the exhaust stroke of the engine.

[0028] The valve train of the present invention is assembled on an engine, and is particularly applicable to an engine operating in a two-stroke cycle. By guiding the intake air for scavenging, it can achieve one power stroke per revolution of the crankshaft. Therefore, the manufacturing cost is reduced, the engine power is increased, and the engine can achieve a power output comparable to that of a large-displacement multi-cylinder engine with a smaller displacement and fewer cylinders. At the same time, the fuel consumption and maintenance cost of the engine are reduced. The volume of the engine is reduced, the weight is lightened, the production cost and maintenance cost are reduced, and the size of the engine support frame is also reduced; since the independent intake and exhaust strokes are eliminated, it is more fuel-efficient. The stroke loss of the engine is significantly reduced, the fuel consumption and mechanical wear caused by the intake and compression strokes are reduced, the thermal efficiency is higher, and it is more energy-saving and environmentally friendly. The present invention is particularly suitable for automotive engines with a relatively long piston stroke.

[0029] In summary, the object of the present invention is achieved.

Claims

1. An engine guided scavenging air distribution mechanism, comprising an overhead valve type intake valve distribution assembly and an exhaust valve distribution assembly arranged on a cylinder block and a cylinder head, wherein the intake valve distribution assembly comprises an intake valve stem with an intake valve head arranged in an intake passage, and an intake valve cam and an intake valve spring are connected to the rear of the intake valve stem to push the intake valve to open and close the intake port, characterized in that: The intake valve stem has an air guide pipe which moves with the intake valve stem through a bracket sleeve. The air guide pipe is close to the intake valve head. A front air outlet is left between the front end of the air guide pipe and the intake valve head. The rear end of the air guide pipe is connected to the intake channel.

2. The engine guided scavenging valve mechanism according to claim 1, characterized in that: The air guide pipe is clearance-matched with the straight section air inlet hole of the air inlet passage close to the air inlet port.

3. The engine guided scavenging valve mechanism according to claim 1 or 2, characterized in that: The support of the air guide pipe is a connecting rod or a connecting rib plate arranged between the inner wall of the middle part of the air guide pipe and the intake valve rod.

4. The engine guided scavenging valve mechanism according to claim 1, characterized in that: The support of the air duct includes a front support and a rear support respectively arranged at the two ends of the air duct. The front support is a connecting rod or a connecting rib plate between the front end air outlet of the air duct and the intake valve rod or the intake valve head; the rear support is a connecting rod or a connecting rib plate between the rear end of the air duct and the intake valve rod.

5. The engine guided scavenging valve mechanism according to claim 1, characterized in that: The front air outlet of the air guide pipe is arranged as an oblique port facing away from the exhaust valve.

6. The engine guided scavenging valve mechanism according to claim 1, characterized in that: The wall of the air guide tube is provided with a plurality of air outlet holes.

7. The engine guided scavenging valve mechanism according to claim 3, characterized in that: The front air outlet of the air guide pipe is arranged as an oblique port facing away from the exhaust valve, and a plurality of air outlet holes are arranged on the wall of the air guide pipe.

8. The engine guided scavenging valve mechanism according to claim 4, characterized in that: The front air outlet of the air guide pipe is arranged as an oblique port facing away from the exhaust valve, and a plurality of air outlet holes are arranged on the wall of the air guide pipe.

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