Engine guide exhaust valve gear

Abstract

The utility model provides a kind of engine guiding exhaust gas distribution mechanism, solved the problem that traditional overhead valve engine distribution mechanism is difficult to clean exhaust gas efficiently under two-stroke working mode, technical scheme is: including the overhead valve exhaust valve distribution assembly and intake valve distribution assembly being set on the engine combustion chamber cylinder head, exhaust valve rod has the gas guide pipe of being packaged with the movement of exhaust valve rod by support, gas guide pipe is close to exhaust valve head, and front end intake port is left between the front end of gas guide pipe and exhaust valve head, and gas guide pipe rear end port communicates exhaust passage.It is discharged exhaust gas by guiding exhaust, it can be applicable to two-stroke working engine, form independent lubricating system and crankshaft rotation complete once work, by guiding exhaust scavenging, improve combustion efficiency and emission performance, greatly improve the scavenging efficiency, and further improve engine working efficiency.

Description

Technical Field

[0001] This utility model relates to the field of internal combustion engine technology, and in particular to an engine guide exhaust valve distribution mechanism, which is applicable to overhead valve type two-stroke engines. Background Technology

[0002] Internal combustion engines have a history of over 150 years since their practical application. Based on their working cycle, they are mainly divided into two-stroke engines and four-stroke engines. Traditional two-stroke engines use side-mounted valves for intake and exhaust, with one revolution of the crankshaft completing one power stroke. The piston completes four processes—exhaust, compression, power, and exhaust—through two strokes, relying on a fresh air-fuel mixture to push out the exhaust gases. Due to limitations in its structure, valve train, and scavenging process, there is a significant amount of residual exhaust gas, and unburned oil is expelled with the exhaust, resulting in low combustion efficiency, poor emissions, severe exhaust pollution, and high fuel consumption. The valve train is a crucial component of the engine. Four-stroke engines typically use an overhead valve train, including the valve assembly and valve train located in the cylinder head of the combustion chamber. The valve assembly includes the exhaust valve and intake / exhaust valve stems and valve heads. The valve train mainly includes the exhaust valve stem, valve head, cam mechanism for driving valve extension and retraction, and valve springs. A four-stroke engine operates by rotating the crankshaft twice to complete one power stroke. The piston completes the four processes of exhaust, compression, power, and exhaust through four strokes. While this solves the exhaust emission problem through separate lubrication, its operating method has significant drawbacks. The crankshaft needs to rotate twice to complete one power stroke, and the valve train must coordinate with the crankshaft to complete all four processes. This results in substantial stroke losses and unnecessary mechanical wear, as well as additional energy and time consumption, leading to fuel waste and mechanical damage. Furthermore, the long power stroke cycle results in a large engine size and increased manufacturing costs. Therefore, there is an urgent need to develop new engine structures and valve designs to solve these technical problems.

[0003] Patent document CN107420195B discloses a two-stroke engine based on a four-stroke engine structure. Its improved valve train structure features a longitudinally positioned exhaust pipe and a longitudinally streamlined exhaust valve head. The valve seat ring inside the exhaust pipe has a narrow throat, and the exhaust valve head seals the area below the valve seat ring. During operation, the transmission ratio between the crankshaft and the exhaust camshaft is 1:1. Each reciprocating motion of the piston within the cylinder drives the crankshaft-connecting rod mechanism to rotate one revolution, which in turn drives the exhaust valve to open once via the camshaft transmission mechanism, forming a two-stroke working cycle. When the exhaust valve opens, the exhaust valve also opens, allowing fresh gas to enter the cylinder combustion chamber through the gap between the narrow throat of the exhaust pipe and the exhaust valve head. The streamlined surface of the exhaust valve head guides the airflow to complete the scavenging process, increasing the effect of expelling post-combustion exhaust gases from the cylinder. The exhaust valve remains within the exhaust pipe at all times. Compared to traditional disc-shaped valve heads, it improves the airflow guidance effect. However, its exhaust valve head is still located at the exhaust pipe opening. Moreover, due to the narrow throat of the exhaust pipe, it greatly hinders the entry of fresh gas and reduces the gas flow, which greatly limits the guiding gas function. In particular, it cannot reach into the piston cylinder and deeper areas to guide the gas to sweep away exhaust gas. Therefore, this valve train cannot efficiently sweep away and remove exhaust gas at the same time during the exhaust process, and cannot further improve combustion efficiency and emission performance. Utility Model Content

[0004] The purpose of this invention is to provide an engine-guided exhaust valve train that solves the problem that traditional overhead valve engine valve trains are unable to efficiently remove exhaust gas in a two-stroke operating mode. By guiding the exhaust gas, it removes exhaust gas, thereby improving combustion efficiency and emission performance.

[0005] The technical solution adopted by this utility model is as follows: The engine guide exhaust valve distribution mechanism includes a top-mounted exhaust valve distribution assembly and an intake valve distribution assembly installed on the cylinder head of the engine combustion chamber. The exhaust valve distribution assembly includes an exhaust valve stem with an exhaust valve head installed in the exhaust passage. An exhaust valve cam and an exhaust valve spring are connected to the rear of the exhaust valve stem to push the exhaust valve to open and close the exhaust port. The key technical point is that the exhaust valve stem has a guide pipe that moves with the exhaust valve stem through a bracket. The guide pipe is close to the exhaust valve head, and a front air inlet is left between the front end of the guide pipe and the exhaust valve head. The rear end of the guide pipe is connected to the exhaust passage.

[0006] The air guide pipe and the straight section of the exhaust port near the exhaust outlet of the exhaust channel are fitted with a clearance.

[0007] The support for the air duct is a connecting rod or connecting rib plate installed between the inner wall of the air duct and the exhaust valve rod in the middle of the air duct.

[0008] The support for the air duct is located near the two ends or the middle of the air duct.

[0009] The advantages and beneficial effects of this utility model are as follows: Because the engine guide exhaust valve timing mechanism adopts an overhead valve timing mechanism, and uses a guide pipe that moves with the exhaust valve stem fixedly mounted on the exhaust valve stem of the timing mechanism, with a front air inlet between the front end of the guide pipe and the exhaust valve head, and an exhaust cam protrusion that can push the exhaust valve head into the engine combustion chamber cavity, the exhaust cam operation can control the guide area formed by the exhaust valve guide pipe extending into the engine combustion chamber cavity. Therefore, the exhaust gas in the cylinder can be guided and discharged into the guide pipe using the guide pipe, achieving deep intake of exhaust gas into the engine combustion chamber and near the top of the engine piston, fully scavenging the exhaust gas. This avoids the problem of traditional exhaust valves only being able to draw in and discharge exhaust gas at the valve opening, resulting in low scavenging efficiency. Therefore, it is particularly suitable for two-stroke engines, forming an independent lubrication system and completing one power stroke per crankshaft rotation. By guiding and scavenging the exhaust gas, combustion efficiency and emission performance are improved, greatly increasing scavenging efficiency and thus improving engine operating efficiency. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings.

[0011] Figure 1 This is a schematic diagram of the structure of this utility model installed on the engine according to an embodiment;

[0012] Figure 2 This is a structural schematic diagram of an embodiment of the present utility model;

[0013] Figure 3 This is a schematic diagram of the exhaust valve structure according to an embodiment of the present invention;

[0014] Figure 4 yes Figure 3 A schematic diagram of the longitudinal sectional view of the structure;

[0015] Figure 5 This is a structural schematic diagram of the second working state of an embodiment of this utility model;

[0016] Figure 6 This is a structural schematic diagram of the third working state of an embodiment of this utility model;

[0017] Figure 7 This is a structural schematic diagram of the fourth working state of an embodiment of this utility model;

[0018] Figure 8 This is a structural schematic diagram of the fifth working state of an embodiment of this utility model;

[0019] Figure 9 This is a schematic diagram of the gas distribution phase of this utility model.

[0020] The numbers in the diagram are explained as follows: 1. Cylinder head, 2. Exhaust passage, 3. Exhaust valve, 4. Engine combustion chamber, 5. Piston, 6. Crankshaft, 7. Crankcase, 8. Exhaust valve cam, 9. Exhaust valve spring, 10. Intake valve cam, 11. Intake valve spring, 12. Intake valve, 13. Exhaust port, 14. Fuel injector, 15. Straight section exhaust port, 16. Air guide area, 31. Exhaust valve stem, 32. Air guide pipe, 33. Exhaust valve head, 34. Front intake port, 35. Rear port, 36. Bracket, 81. Protrusion. Detailed Implementation

[0021] according to Figure 1-9 This utility model will be described in detail, and its implementation will be illustrated by examples. Figure 1 and Figure 2 As shown, an engine-guided exhaust valve train includes an overhead valve type exhaust valve train assembly and an intake valve train assembly mounted on the cylinder head 1 of the engine combustion chamber. The exhaust valve train assembly includes an exhaust valve stem 31 with an exhaust valve head 33 mounted in the exhaust passage 2. An exhaust valve cam 8 and an exhaust valve spring 9 are connected to the rear of the exhaust valve stem to push the exhaust valve to open and close the exhaust port 13. The engine block assembly includes an engine combustion chamber 4, a cylinder head 1, and a crankcase 7, etc. The valve train uses an overhead valve design. An exhaust valve 3, driven by the exhaust valve cam 8 and the exhaust valve spring 9, is mounted on the cylinder head 1. The front of the exhaust valve is located at a straight section exhaust port 21 connecting the exhaust passage 2 and the exhaust port. The exhaust valve head 33 can block and open the exhaust port 13. The crankshaft connecting rod mechanism's crankshaft 6 drives the camshaft and crankshaft to rotate synchronously via timing gears, chains, or timing belts, operating in a two-stroke mode. The improvement lies in: Figure 3 As shown, the exhaust valve stem 31 of the valve train is fixedly fitted with an air guide pipe 32 at its front end via a bracket 36. The air guide pipe is movably positioned within the straight section of the exhaust port 21, which connects the exhaust passage 2 and the exhaust outlet. The air guide pipe can move with the exhaust valve stem. A clearance fit can be formed between the inner wall of the straight section of the exhaust port 21 and the air guide pipe 32, reducing the loss of fresh air through this gap and minimizing or preventing contact between them, thus reducing frictional resistance between the valve and the air guide pipe caused by the valve's up-and-down movement. Figure 3 and Figure 4As shown, the exhaust valve stem 31 of the exhaust valve has a disc-shaped exhaust valve head 33 at its front end. A certain distance is left between the front end of the air guide pipe and the exhaust valve head to form a front air intake 34. The rear end 35 of the air guide pipe connects to the exhaust passage 2, so that the inner cavity of the air guide pipe forms a passage connecting the exhaust passage and the exhaust port. The exhaust cam 8 of the valve train may be provided with an exhaust cam protrusion 81 that pushes the front end of the air guide pipe 32 of the exhaust valve into the inner cavity of the engine combustion chamber 4. The exhaust cam 8 of this valve train has a larger protrusion than the intake cam 10 of a conventional intake valve 12. The diameter and length of the exhaust cam 8 are both greater than those of the intake cam 10. The exhaust valve spring 9 is thicker than the intake valve spring 11, resulting in a longer stroke to push the exhaust valve stem and head. This allows the exhaust valve head to extend into the air guide area 15 between the upper part to the center position or near the bottom dead center of the piston in the engine combustion chamber. The length of the exhaust cam protrusion and the depth of the exhaust valve head extending into the engine combustion chamber can be matched by the air guide pipe. Therefore, the fresh air entering the cylinder can be guided into the air guide area by the air guide pipe, achieving deep intake of exhaust gas from the engine combustion chamber and near the top of the piston. This thoroughly removes the exhaust gas, avoiding the problem of low scavenging efficiency in traditional exhaust valves that can only intake and exhaust exhaust gas at the valve opening. This is different from the traditional engine exhaust valve operation method, which only allows the valve head to leave the valve opening.

[0022] As a further improvement, such as Figure 3 and Figure 4 As shown, the support 36 of the air guide pipe 32 can be a connecting rod or connecting rib between the inner wall of the air guide pipe near both ends or in the middle and the exhaust valve stem 31, so that the air guide pipe is stably connected to the exhaust valve stem. The connecting rib can be in the shape of a longitudinal thin sheet, which can reduce air resistance. The air guide pipe and the support can be connected and fixed by welding to the exhaust valve stem or by an integral structure.

[0023] Working methods and principles: such as Figure 1 , Figures 5 to 9 As shown, the power stroke, exhaust, intake, and compression processes of a two-stroke diesel engine with valves are sequentially displayed, along with the operating states at each stage. This utility model engine is a two-stroke engine, and its valve train differs from that of traditional engines. In a traditional four-stroke engine, the exhaust valve opens and closes only once every two crankshaft revolutions, while in this engine, the exhaust valve opens and closes once for every one revolution of the crankshaft.

[0024] The work process includes the following steps: Figure 1In the initial working state, that is, at the beginning of the power stroke, both exhaust valve 3 and intake valve 12 are closed, piston 5 is close to the top dead center position, and the protrusions of exhaust valve cam 8 and intake valve cam 10 rotate away from the spring position; then the crankshaft drives the camshaft to rotate counterclockwise synchronously through the timing gear, chain or timing belt; during the cycle, this process is also the power stroke, pushing the piston to move downward from the top dead center, and exhaust valve cam 8, exhaust valve cam 10 and crankshaft 6 rotate counterclockwise.

[0025] like Figure 5 As shown, the exhaust valve cam 10 is set to push the exhaust valve spring 11 to open the exhaust valve 12 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, so that the exhaust gas in the upper part of the combustion chamber after combustion can be discharged from the exhaust port 13.

[0026] like Figure 6 As shown, before the piston 5 continues to move to the bottom dead center, the intake valve cam 10 rotates to the state of opening the exhaust valve, and begins to send fresh air into the engine combustion chamber for the intake process; at this time, the exhaust valve cam 8 pushes the exhaust valve head 33 into the engine combustion chamber cavity, so that the exhaust valve reaches the maximum opening depth, and the exhaust duct extends into the engine combustion chamber. It can use the duct to guide the exhaust gas from the middle of the combustion chamber to the piston top duct area 15 into the exhaust duct, and discharge the exhaust gas that has been burned at the bottom of the engine combustion chamber out of the cylinder body, so as to achieve the purpose of sweeping exhaust gas deep into the engine combustion chamber. After reaching the maximum depth, it retracts upward, so that the movement of the exhaust valve head does not interfere with or collide with the movement of the piston.

[0027] like Figure 7 As shown, after the piston continues to move to bottom dead center, it gradually moves upwards. During this process, the intake valve opens, and after scavenging is completed, the exhaust valve 12 closes prematurely, and the exhaust valve 3 guide gradually retracts to close the exhaust valve. Alternatively, the exhaust valve and exhaust valve can be set to close simultaneously; this position coincides with the end of the piston's fresh air exchange.

[0028] like Figure 8 The diagram shows the compression process of the engine piston, with the exhaust valve at its closed position, marking the beginning of the compression stroke. Piston 7 continues to move upwards to compress the air, reaching top dead center to complete the compression stroke.

[0029] like Figure 1As shown, once the engine reaches its initial working position, the air-fuel mixture is ignited, pushing the piston to perform work. With the piston near top dead center, fuel injector 14 operates, injecting atomized diesel fuel into the combustion chamber. Alternatively, gasoline or other combustible gases can be injected into the engine cylinder after the exhaust valve is closed. Adding a spark plug transforms it into a gasoline engine. Alternatively, the engine can burn natural gas or liquefied petroleum gas (LPG). After completing one working cycle, the engine enters the next power stroke.

[0030] like Figure 9 The diagram shows the valve timing of this invention. The crankshaft, intake camshaft, and exhaust camshaft rotate counter-clockwise along the coordinate axis. 'a' represents the angular range of the exhaust camshaft from opening to closing, 'b' represents the angular range of the intake camshaft from opening to closing, 'c' represents the angular range of the piston crankshaft's power stroke, and 'd' represents the angular range of the piston crankshaft's compression stroke. The intake valve can open at a position of 28 to 35 degrees before the piston reaches bottom dead center, and the exhaust valve can open at a position of 30 to 60 degrees before the intake valve opens. The intake and exhaust valves can close simultaneously or with a delay. The angle range of the protrusions on the intake and exhaust valve cams can be adjusted, reducing the engine's intake and exhaust strokes.

[0031] This utility model's valve train is mounted on an engine, particularly suitable for two-stroke engines. By guiding exhaust gas through scavenging, it ensures that the engine performs work once per crankshaft revolution. The exhaust gas is guided from the cylinder into the intake manifold via a scavenging pipe, allowing it to penetrate deep into the combustion chamber and near the piston top, effectively scavenging the exhaust gas. This reduces manufacturing costs, increases engine power, and enables the engine to achieve power output comparable to large-displacement, multi-cylinder engines with a smaller displacement and fewer cylinders. It also reduces fuel consumption and maintenance costs. The design reduces engine size and weight, lowering production and maintenance costs, while also reducing the size of the engine support frame. By eliminating separate intake and exhaust strokes, it improves fuel efficiency. It significantly reduces engine stroke losses, minimizing fuel consumption and mechanical wear caused by the intake and compression strokes, resulting in higher thermal efficiency and greater energy savings and environmental friendliness. This utility model is particularly suitable for automotive engines with longer piston formations.

[0032] In summary, the purpose of this utility model has been achieved.

Claims

1. An engine-guided exhaust valve train, comprising an overhead valve type exhaust valve train assembly and an intake valve train assembly disposed on the cylinder head of the engine combustion chamber, the exhaust valve train assembly comprising an exhaust valve stem with an exhaust valve head disposed in the exhaust passage, the rear of the exhaust valve stem being connected to an exhaust valve cam and an exhaust valve spring to push the exhaust valve to open and close the exhaust port, characterized in that: The exhaust valve stem has an air guide pipe that moves with the exhaust valve stem via a bracket. The air guide pipe is close to the exhaust valve head, and there is a front air inlet between the front end of the air guide pipe and the exhaust valve head. The rear end of the air guide pipe is connected to the exhaust channel.

2. The engine guide exhaust valve timing mechanism according to claim 1, characterized in that: The air guide pipe and the straight section of the exhaust port near the exhaust outlet of the exhaust channel are fitted with a clearance.

3. The engine guide exhaust valve timing mechanism according to claim 1 or 2, characterized in that: The support for the air duct is a connecting rod or connecting rib plate installed between the inner wall of the air duct and the exhaust valve rod in the middle of the air duct.

4. The engine guide exhaust valve timing mechanism according to claim 1, characterized in that: The support for the air duct is located near the two ends or the middle of the air duct.

Images