Guiding scavenging valve mechanism of engine

Abstract

The utility model 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 an air guide pipe moving along with the air inlet valve rod is arranged between the air inlet valve rod and the air inlet valve head through a support. A front-end air outlet is reserved between the front end of the air guide pipe and the head of the air inlet valve, and a rear port of the air guide pipe is communicated with the air inlet channel. Waste gas is exhausted by guiding and scavenging the inlet gas, the two-stroke-type engine exhaust pipe can be suitable for a two-stroke-type working engine, the combustion efficiency and the emission performance are improved by guiding and scavenging the inlet gas, the scavenging efficiency is greatly improved, and then the working efficiency of the engine is improved.

Description

Technical Field

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

[0002] Internal combustion engines have been around for over 150 years, and are mainly classified into two-stroke and four-stroke engines according to their working cycle. Traditional two-stroke engines use a side-mounted valve intake and exhaust system with mixed lubrication. One revolution of the crankshaft completes one power stroke, while the piston completes the four processes of intake, compression, power, and exhaust through two strokes. The exhaust gas is propelled out by a fresh air-fuel mixture. 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 block and cylinder head. The valve assembly includes intake and exhaust valves, primarily consisting of the intake valve stem and valve head. The valve train primarily includes the intake valve stem, valve head, and the cam mechanism and valve springs used to drive the valve extension and retraction. A four-stroke engine operates by rotating the crankshaft twice to complete one power stroke. The piston completes the four processes of intake, compression, power, and exhaust through four strokes. While it addresses exhaust emissions 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, consuming additional energy and time, 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 intake manifold and a streamlined intake valve head. The valve seat ring within the intake manifold has a narrow throat, and the intake valve head seals the area below the valve seat ring. During operation, the transmission ratio between the crankshaft and the intake / exhaust camshafts 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 intake and exhaust valves to open once each via the camshaft transmission mechanism, forming a two-stroke working cycle. 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 manifold and the intake valve head. The streamlined surface of the intake valve head guides the airflow to complete the scavenging process, increasing the effect of expelling exhaust gases after combustion in the cylinder. The intake valve remains within the intake manifold at all times. Compared to traditional disc-mounted valve heads, it enhances the airflow guidance effect. However, its intake valve head is still located at the intake manifold opening. Furthermore, due to the narrow throat of the intake manifold, it greatly hinders the entry of fresh gas, reduces gas flow, and severely limits the guiding gas function. In particular, it cannot reach into the piston cylinder and deeper areas to guide gas and scavenge exhaust gases. Therefore, this valve train mechanism cannot efficiently scavenge exhaust gases simultaneously during the intake 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 scavenging valve train mechanism, which solves the problem that traditional overhead valve engine valve train mechanisms are difficult to efficiently scavenge exhaust gas in two-stroke operation. It improves combustion efficiency and emission performance by guiding the intake air to scavenge the exhaust gas.

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

[0006] The air guide tube and the straight section of the air intake hole near the air inlet of the air intake channel are fitted with a clearance.

[0007] The support for the air duct includes a front support and a rear support respectively disposed at the two ends of the air duct. The front support is a connecting rod or connecting rib between the air outlet at the front end of the air duct and the head of the air intake valve; the rear support is a connecting rod or connecting rib between the rear end of the air duct and the air intake valve stem.

[0008] The air outlet at the front end of the air duct is set as an angled port facing away from the exhaust valve.

[0009] The air duct wall is provided with multiple air outlets.

[0010] The advantages and beneficial effects of this utility model are as follows: Because the engine's guided scavenging valve train adopts an overhead valve train, and a guide pipe that moves with the intake valve stem is installed between the intake valve stem and the intake valve head via a bracket, with a front outlet between the front end of the guide pipe and the intake valve head, and an intake cam protrusion that can push the intake valve head into the cylinder cavity can be provided on the intake cam of the valve train, the guide area formed by the intake valve guide pipe extending into the cylinder cavity can be controlled by the operation of the intake cam. This system utilizes a scavenging pipe to guide fresh air entering the cylinder into the scavenging area, allowing it to penetrate deep into the cylinder to purge the exhaust gases after combustion. This opens the exhaust valve and thoroughly removes the exhaust gases, avoiding the problem of traditional intake valves only scavenging exhaust gases at the valve opening and having 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 the intake air to scaveng, it improves combustion efficiency and emission performance, greatly enhancing scavenging efficiency and thus improving engine operating efficiency. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings.

[0012] Figure 1 This is a schematic diagram of the structure of this utility model installed on the engine according to an embodiment;

[0013] Figure 2 This is a structural schematic diagram of an embodiment of the present utility model;

[0014] Figure 3 This is a schematic diagram of the first intake valve structure according to an embodiment of the present utility model;

[0015] Figure 4 yes Figure 3 A schematic diagram of the longitudinal sectional view of the structure;

[0016] Figure 5 This is a schematic diagram of a second intake valve structure according to an embodiment of the present invention;

[0017] Figure 6 This is a schematic diagram of a third intake valve structure according to an embodiment of the present invention;

[0018] Figure 7 This is a structural schematic diagram of the second working state of an embodiment of this utility model;

[0019] Figure 8 This is a structural schematic diagram of the third working state of an embodiment of this utility model;

[0020] Figure 9 This is a structural schematic diagram of the fourth working state of an embodiment of this utility model;

[0021] Figure 10 This is a schematic diagram of the working state of the third embodiment of the present invention.

[0022] The numbers in the diagram are explained as follows: 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 guide area, 21. Straight section intake port, 31. Intake valve stem, 32. Air guide pipe, 33. Intake valve head, 34. Front exhaust port, 35. Rear port, 36. Bracket, 37. Exhaust port, 81. Protrusion. Detailed Implementation

[0023] according to Figures 1-10 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 scavenging valve train includes an overhead valve intake valve train assembly and an exhaust valve train assembly mounted 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 mounted in the intake passage 2. The rear of the intake valve stem is connected to an intake valve cam 8 and an intake valve spring 9, which push the intake valve to open and close the intake port 13. The engine block assembly includes a cylinder block 4, a cylinder head 1, and a crankcase 7, etc. The valve train adopts an overhead valve design. An intake valve 3 driven by the intake valve cam 8 and the intake valve spring 9 is provided on the cylinder head 1. The front of the intake valve is provided with a straight section intake hole 21 connecting the intake passage 2 and the intake port. The intake valve head 33 can block and open the intake port. 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: Figures 1-3 As shown, the intake valve stem 31 of the valve train is fixedly fitted with an air guide tube 32 via a bracket 36 at its front. The air guide tube is movably positioned within the straight section of the intake port 21 that connects the intake channel 2 and the intake inlet. The air guide tube can move with the intake valve stem. A clearance fit can be formed between the inner wall of the straight section of the intake port 21 and the air guide tube 32, which can reduce the loss of fresh air through the gap between them and reduce or prevent contact between them, thus reducing the frictional resistance generated between the valve and the air guide tube due to the up-and-down movement of the valve. Figures 2-4As shown, the intake valve stem 31 of the intake valve is connected to the intake valve head via a bracket, and an air guide pipe that moves with the intake valve stem is installed. The intake valve head 33 is disc-shaped, and a certain distance is left between the front end of the air guide pipe and the intake valve head to form a front outlet 34. The rear end 35 of the air guide pipe connects to the intake channel 2, so that the inner cavity of the air guide pipe forms a passage connecting the intake channel and the intake port. The intake cam 8 of the valve train may be provided with an intake cam protrusion 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 this valve train has a larger cam protrusion than conventional intake cams. The diameter of the intake cam 8 and the length of the intake valve stem are both greater than those of the exhaust cam 10. The intake valve spring 9 is thicker than the exhaust valve spring 11, resulting in a longer stroke to push the intake valve stem and head. This allows the intake valve head to extend into the air guide area 15 between the upper part of the cylinder cavity and the center position or near the bottom dead center of the piston. The length of the intake cam protrusion and the depth of the intake valve head extending into the cylinder cavity can be matched by the air guide tube. Therefore, fresh air entering the cylinder can be guided into the air guide area through the air guide tube to achieve the purpose of deep scavenging of exhaust gas into the cylinder cavity. This is different from the traditional intake valve operation method of engines, which only makes the valve head disengage from the valve door to form an open state. The engine's intake passage is connected to the exhaust pipe of an external turbocharger or supercharger system (i.e., a Roots blower), or it can be connected to the exhaust pipes of both the turbocharger and supercharger systems. The purpose is to allow pressurized fresh air to enter the engine's combustion chamber through the intake valve's duct.

[0024] As a further improvement, such as Figure 3 and Figure 4 As shown, the support 36 of the air duct 32 can be constructed by including a front support and a rear support respectively disposed at both ends of the air duct. The front support is a connecting rod or connecting rib near the air outlet 34 at the front end of the air duct and the intake valve head 33, and the rear support is a connecting rod or connecting rib near the rear end 35 of the air duct and the intake valve stem 31. This structure can not only securely connect the air duct to the intake valve, but also reduce obstruction of the inner cavity of the air duct, thereby increasing stability. The connecting rib can be in the shape of a longitudinal thin sheet, which can reduce air resistance.

[0025] As a further improvement, such as Figure 5As shown, the front outlet 34 of the air guide pipe 32 can be configured as an angled port facing away from the exhaust valve. The lower outlet of the air guide pipe is inclined to the direction of the intake valve head, so that when the fresh gas is ejected from the front outlet, it is directed towards the inner wall of the cylinder body away from the exhaust valve. This allows most of the gas entering the cylinder body to be sprayed towards the cylinder wall and the top of the piston. The gas rebounds from the inner wall of the cylinder body and the top of the piston to clean up the combusted exhaust gas, thus better removing the combusted exhaust gas from the cylinder body and increasing the efficiency of exhaust gas cleaning. To prevent the air guide pipe of the intake valve from changing the direction of air blowing due to rotation, the valve guide rod of the intake valve can be made into an ellipse, or an anti-rotation locating pin can be made on the valve guide rod and the air guide pipe of the valve, or the intake guide rod hole in the cylinder head can be used to limit and prevent rotation.

[0026] As a further improvement, such as Figure 6 As shown, multiple air outlets 37 can be provided on the wall of the air guide pipe 32, so that gas can be continuously injected and exhaust gas can be swept out as the air guide pipe extends into the cylinder body from the air inlet.

[0027] Working methods and principles: such as Figure 1 , Figures 7-10 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 intake and exhaust valves open and close only once every two crankshaft revolutions, while in this engine, the intake and exhaust valves each open and close once per crankshaft revolution.

[0028] The work process includes the following steps: Figure 1 In the initial working state, that is, at the beginning of the power stroke, both intake valve 3 and exhaust valve 12 are closed, piston 5 is close to the top dead center position, and the protrusions of intake valve cam 8 and exhaust 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 intake valve cam 8, exhaust valve cam 10 and crankshaft 6 rotate clockwise.

[0029] like Figure 7 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 after combustion can be discharged from the exhaust port 13.

[0030] like Figure 8As shown, before the piston 5 continues to move to the bottom dead center, the intake valve cam 8 rotates to the open intake valve state. At this time, the intake valve has just opened and begins to send fresh air into the cylinder to carry out the intake process.

[0031] like Figure 9 As shown, the process of intake and exhaust occurs simultaneously. 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 intake valve head 33 into the cylinder cavity, so that the intake valve reaches the maximum opening depth. This allows the intake duct to extend into the cylinder, and the fresh air entering the cylinder can be guided into the air guide area 15 through the air guide to achieve the purpose of sweeping exhaust gas deep into the cylinder. The pressurized fresh air is sent to the bottom of the cylinder and the combusted exhaust gas is discharged from the cylinder. After reaching the maximum depth, it retracts upward, so that the movement of the intake valve head does not interfere with or collide with the movement of the piston.

[0032] During the compression process of the engine piston, after scavenging is completed, the exhaust valve 12 closes prematurely, and the intake valve 3 guide gradually retracts, closing the intake valve. Alternatively, the exhaust and intake valves can be closed simultaneously. This position coincides with the end of the piston's replacement of fresh air, the closing position of both the intake and exhaust valves, and the beginning of the compression stroke. The piston 7 then continues to move upwards to continue the air compression process, reaching top dead center to complete the compression stroke.

[0033] like Figure 1 As shown, once the engine reaches its initial operating 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 intake and exhaust valves are 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.

[0034] like Figure 10 The diagram shows a third embodiment of the intake valve's working state. The intake valve 3 uses an angled outlet 34 at the front end of the air guide pipe 32. The outlet extends into the air guide area between the upper part of the cylinder body and near the piston's bottom dead center for scavenging. The closer the outlet is to the piston's bottom dead center, the better the scavenging effect. Ideally, the outlet should extend into the air guide area between the piston's bottom dead center and the center of the cylinder body (with the air guide pipe close to the piston top). The air guide pipe wall has multiple outlet holes 37, allowing some fresh gas to be ejected from the outlet towards the cylinder body wall away from the exhaust valve. This rebound of gas from the cylinder body wall scavenges the exhaust gas, increasing the efficiency of exhaust gas scavenging.

[0035] This utility model's valve train is mounted on an engine, and is especially suitable for two-stroke engines. By guiding and scavenging the intake air, it can achieve one power stroke per crankshaft rotation.

[0036] In summary, the purpose of this utility model has been achieved.

Claims

1. An engine guided scavenging valve train, comprising an overhead valve type intake valve train assembly and an exhaust valve train assembly mounted on the cylinder head of the cylinder block, wherein the intake valve train assembly includes an intake valve stem with an intake valve head mounted in the 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: An air guide tube that moves with the intake valve stem is provided between the intake valve stem and the intake valve head via a bracket. The air guide tube is close to the intake valve head, and a front air outlet is left between the front end of the air guide tube and the intake valve head. The rear end of the air guide tube is connected to the intake channel.

2. The engine guide scavenging valve distribution mechanism according to claim 1, characterized in that: The air guide tube and the straight section of the air intake hole near the air inlet of the air intake channel are fitted with a clearance.

3. The engine guide scavenging valve distribution mechanism according to claim 1 or 2, characterized in that: The support for the air duct includes a front support and a rear support respectively disposed at the two ends of the air duct. The front support is a connecting rod or connecting rib between the air outlet at the front end of the air duct and the head of the air intake valve; the rear support is a connecting rod or connecting rib between the rear end of the air duct and the air intake valve stem.

4. The engine guide scavenging valve distribution mechanism according to claim 1, characterized in that: The air outlet at the front end of the air duct is set as an angled port facing away from the exhaust valve.

5. The engine guide scavenging valve distribution mechanism according to claim 1, characterized in that: The air duct wall is provided with multiple air outlets.

6. The engine guide scavenging valve distribution mechanism according to claim 3, characterized in that: The air outlet at the front end of the air guide pipe is set as an oblique port facing away from the exhaust valve, and the wall of the air guide pipe is provided with multiple air outlet holes.

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