A valve timing system for a V-type two-cylinder four-valve engine

Abstract

The application relates to a valve timing system of a V-type two-cylinder four-valve engine. The application comprises cylinder blocks arranged in a V type, cylinder heads arranged on two sides of the cylinder blocks respectively, two intake valves and two exhaust valves arranged on each cylinder head respectively, a combustion chamber of the cylinder head being a pinnacled combustion chamber, an air inlet of the cylinder head being arranged at the front end of the engine, an exhaust port of the cylinder head being arranged at the rear end of the engine, and a space for accommodating a valve timing system being formed in the middle of the engine; the valve timing system comprises a camshaft arranged in the middle of the cylinder block and driven to rotate by a crankshaft, four cams arranged on the camshaft in the axial direction, four tappets, four push rods, one end of each push rod being movably connected with a corresponding tappet, and a rocker arm mechanism comprising two rocker arm seats oppositely arranged on each cylinder head and intake rocker arms and exhaust rocker arms rotatably arranged on each rocker arm seat. Under the premise of meeting various requirements of the vehicle level, high performance, small size and low cost of the engine are realized.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a valve train system for a V-type two-cylinder four-valve engine. Background Technology

[0002] China's automobile industry achieved a production and sales volume exceeding 30 million vehicles in 2023, with new energy vehicle production and sales reaching 9.587 million and 9.495 million units respectively, representing year-on-year growth of 35.8% and 37.9%. Among new energy vehicles, range-extended electric vehicles (REEVs) are widely adopted by most well-known automakers due to their lower technological barriers and significant fuel-saving effects. Most mainstream REEVs in China use 1.5L-2.0L naturally aspirated or turbocharged high-efficiency gasoline engines paired with high-efficiency generators. Products featuring large vehicle models (B+ and above) with high-power range extenders have gained market acceptance, while products featuring small vehicle models (A00 and A0 class) with low-power range extenders represent a market gap.

[0003] The key factors in developing low-power range extenders are size, performance, and cost. The size of the engine determines whether a low-power range extender can be matched with the compact engine bay of small vehicles (A00 class, A0 class), while the engine performance affects the powertrain's fuel-electric conversion rate and fuel economy. Only when all of these factors are controlled within a certain range will the product be accepted by the market.

[0004] Reference Figure 4 , Figure 5 As shown, most four-valve V-type two-cylinder gasoline engines on the market currently employ either an overhead camshaft (OHC) with a dome-shaped combustion chamber or a center camshaft with a flat-top combustion chamber. The OHC configuration ensures high engine performance and is relatively easy to implement. However, the OHC's valve train is located above the cylinder head, and the two camshafts result in an excessively large engine size, making it difficult to fit into the compact engine bays of smaller vehicles, while also increasing weight and cost. The center camshaft configuration, while easier to implement, has smaller valve diameters, hindering high-speed intake and resulting in lower power output. It also makes it difficult to achieve tumble flow, leading to slower in-cylinder combustion, incomplete combustion, higher fuel consumption, higher exhaust temperatures, and reduced engine reliability.

[0005] How to balance the power, economy, reliability, and overall size of a V-type two-cylinder four-valve engine is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] Therefore, the present invention provides a valve train system for a V-type two-cylinder four-valve engine, which achieves high performance, small size and low cost of engine while meeting various automotive-grade requirements.

[0007] To solve the above-mentioned technical problems, the present invention provides a valve train system for a V-type two-cylinder four-valve engine, comprising: The cylinder block is arranged in a V-shape, and cylinder heads are provided on both sides of the cylinder block. Each cylinder head is provided with two intake valves and two exhaust valves. The cylinder head combustion chamber is a canopy combustion chamber. The intake port of the cylinder head is located at the front of the engine, and the exhaust port of the cylinder head is located at the rear of the engine, so that the middle of the engine forms a space for accommodating the valve train. The gas distribution mechanism includes: A camshaft is located in the middle of the cylinder block and is driven to rotate by a crankshaft. The camshaft has four cams arranged axially. Four pushers are respectively disposed on one side of the four cams and are driven by their respective cams; Four push rods, one end of each push rod being movably connected to the corresponding push column; The rocker arm mechanism includes two rocker arm seats mounted on each of the cylinder heads and arranged opposite to each other, and an intake rocker arm and an exhaust rocker arm that rotate with each of the rocker arm seats; the intake rocker arm and the exhaust rocker arm are connected to the other end of the corresponding push rod; the intake rocker arm is connected to the two corresponding intake valves, and the exhaust rocker arm is connected to the two corresponding exhaust valves.

[0008] In one embodiment of the present invention, the center line connecting the two intake valves on the intake rocker arm and the two exhaust valves on the exhaust rocker arm is perpendicular to the axial direction of the camshaft.

[0009] In one embodiment of the present invention, the tappet is a hydraulic tappet or a mechanical tappet.

[0010] In one embodiment of the present invention, the intake valve and the exhaust valve, which are arranged on the same rocker arm mount and parallel to the axial direction of the camshaft, have an angle of 35 to 45°.

[0011] In one embodiment of the present invention, the included angle between two push rods on the same rocker arm seat is 5~20°.

[0012] In one embodiment of the present invention, on one of the rocker arm seats, the push rod connected to the intake rocker arm makes an angle of 3 to 6° with the radial direction of the camshaft, and the push rod connected to the exhaust rocker arm makes an angle of 4 to 8° with the radial direction of the camshaft. On another rocker arm mount, the pushrod connected to the intake rocker arm makes an angle of 3~6° with the radial direction of the camshaft, and the pushrod connected to the exhaust rocker arm makes an angle of 4~8° with the radial direction of the camshaft.

[0013] In one embodiment of the present invention, a rocker arm shaft is provided between the intake rocker arm and the exhaust rocker arm and the corresponding rocker arm seat, the rocker arm shaft and the corresponding rocker arm seat are clearance fit, and the rocker arm seat is fixed to the cylinder head by bolts.

[0014] In one embodiment of the present invention, the camshaft, the intake rocker arm, the exhaust rocker arm, and the rocker arm shaft are all made of steel.

[0015] The technical solution of the present invention has the following advantages compared with the prior art: The present invention discloses a valve train system for a V-type two-cylinder four-valve engine. The intake port of the cylinder head is placed at the front of the engine, and the exhaust port is placed at the rear. This provides sufficient space in the middle of the engine to accommodate the valve train mechanism (camshaft, tappets, and pushrods). Simultaneously, the camshaft is located in the middle of the cylinder block, shortening the distance between the camshaft and crankshaft, simplifying the transmission mechanism, and reducing the overall height and width, thus achieving a compact engine design. The cylinder head combustion chamber adopts a domed combustion chamber, which, compared to a flat-top combustion chamber, has a larger intake and exhaust valve diameter, lower intake and exhaust resistance, and smoother intake and exhaust flow. It also allows for a high tumble intensity design, resulting in faster combustion rate, lower exhaust temperature, and improved engine power, economy, and reliability.

[0016] In the valve train layout, the center lines connecting the two intake valves and the two exhaust valves are perpendicular to the crankshaft direction. The centrally located camshaft, pushrod, and rocker arm design in the cylinder head allows for valve angle design, and the cylinder head can accommodate a canopy combustion chamber, ensuring high engine performance. The number of camshafts has been reduced from two to one, significantly lowering costs. Attached Figure Description

[0017] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the valve train system of the V-type two-cylinder four-valve engine of the present invention.

[0019] Figure 2 This is a schematic diagram of the gas distribution mechanism of the present invention.

[0020] Figure 3 This is a schematic diagram of the arrangement of tappets, pushrods, valves and rocker arms of the present invention.

[0021] Figure 4 This is a schematic diagram of a conventional double overhead camshaft arrangement.

[0022] Figure 5 This is a schematic diagram of a conventional center-mounted camshaft arrangement.

[0023] Explanation of reference numerals on the accompanying drawings: 1. Cylinder block; 11. Cylinder head; 11a. Intake port; 11b. Exhaust port; 21. Intake valve; 22. Exhaust valve; 3. Camshaft; 4. Support column; 5. Push rod; 6. Rocker arm mechanism; 61. Rocker arm base; 62. Intake rocker arm; 63. Exhaust rocker arm. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0025] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0026] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0028] Reference Figure 1 , Figure 2 , Figure 3 As shown, the valve train system of a V-type two-cylinder four-valve engine of the present invention includes: The cylinder block 1 is arranged in a V-shape, and cylinder heads 11 are respectively provided on both sides of the cylinder block 1. Each cylinder head 11 is provided with two intake valves 21 and two exhaust valves 22. The combustion chamber of the cylinder head 11 is a canopy combustion chamber. The intake port 11a of the cylinder head 11 is arranged at the front end of the engine, and the exhaust port 11b of the cylinder head 11 is arranged at the rear end of the engine, so that the middle of the engine forms a space for accommodating the valve train mechanism. The gas distribution mechanism includes: Camshaft 3 is located in the middle of cylinder block 1 and is driven to rotate by crankshaft. Camshaft 3 has four cams arranged axially. Four pushers 4 are respectively disposed on one side of the four cams and are driven by their respective cams; Four push rods 5, one end of each push rod is movably connected to the corresponding push column 4; The rocker arm mechanism 6 includes two rocker arm seats 61 mounted on each of the cylinder heads 11 and arranged opposite to each other, and an intake rocker arm 62 and an exhaust rocker arm 63 that rotate with each of the rocker arm seats 61; the intake rocker arm 62 and the exhaust rocker arm 63 are connected to the other end of the corresponding push rod 5; the intake rocker arm 62 is connected to the two corresponding intake valves 21, and the exhaust rocker arm 63 is connected to the two corresponding exhaust valves 22.

[0029] Specifically, the center line connecting the two intake valves 21 on the intake rocker arm 62 and the two exhaust valves 22 on the exhaust rocker arm 63 is perpendicular to the axial direction of the camshaft 3.

[0030] Specifically, the tappet 4 is a hydraulic tappet or a mechanical tappet.

[0031] Specifically, on the same rocker arm seat 61, the included angle between the intake valve 21 and the exhaust valve 22, which are arranged parallel to the axial direction of the camshaft 3, is 35~45°, and in this embodiment it is set to 41°.

[0032] Specifically, on the same rocker arm seat 61, the included angle between the two push rods 5 is 5~20°, and in this embodiment it is set to 7.6°.

[0033] Specifically, on one of the rocker arm seats 61, the angle between the push rod 5 connected to the intake rocker arm 62 and the radial direction of the camshaft 3 is 3~6°, and in this embodiment it is set to 3.5°; the angle between the push rod 5 connected to the exhaust rocker arm 63 and the radial direction of the camshaft 3 is 4~8°, and in this embodiment it is set to 6.5°. On another rocker arm mount 61, the push rod 5 connected to the intake rocker arm 62 has an angle of 3~6° with the radial direction of the camshaft 3, which is set to 3.9° in this embodiment. The push rod 5 connected to the exhaust rocker arm 63 has an angle of 4~8° with the radial direction of the camshaft 3, which is set to 5.9° in this embodiment.

[0034] Specifically, the intake rocker arm 62 and the exhaust rocker arm 63 are provided with rocker arm shafts between them and the corresponding rocker arm seats 61. The rocker arm shafts and the corresponding rocker arm seats 61 are clearance fits. The rocker arm seats 61 are fixed to the cylinder head 11 by bolts.

[0035] Specifically, the camshaft 3, the intake rocker arm 62, the exhaust rocker arm 63, and the rocker arm shaft are all made of steel.

[0036] Furthermore, the cylinder head 11 of the V-type two-cylinder engine is cast from die-cast aluminum. The intake manifold, exhaust manifold, and cooling water jacket of the cylinder head 11 are sand-cast and integrated within the cylinder head 11. This method enables the production and manufacturing of components. By arranging the intake and exhaust manifolds at the front and rear ends of the cylinder head 11, a centrally located camshaft 3 valve train can be installed in the middle of the engine block. Oil passages are cast and machined on the rocker arm seat 61, and oil is applied to the cylinder head 11 to provide forced lubrication for the valve train.

[0037] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A valve train system for a V-type two-cylinder four-valve engine, characterized in that, include: The cylinder block (1) is arranged in a V shape. Cylinder heads (11) are provided on both sides of the cylinder block (1). Each cylinder head (11) is provided with two intake valves (21) and two exhaust valves (22). The combustion chamber of the cylinder head (11) is a canopy combustion chamber. The intake port (11a) of the cylinder head (11) is arranged at the front end of the engine, and the exhaust port (11b) of the cylinder head (11) is arranged at the rear end of the engine, so that the middle part of the engine forms a space for accommodating the valve train. The gas distribution mechanism includes: A camshaft (3) is arranged in the middle of the cylinder block (1) and driven to rotate by the crankshaft. The camshaft (3) has four cams arranged along the axial direction. Four tappets (4) are respectively disposed on one side of the four cams and are driven by their respective cams; Four push rods (5), one end of each push rod is movably connected to the corresponding push column (4); The rocker arm mechanism (6) includes two rocker arm seats (61) mounted on each of the cylinder heads (11) and arranged opposite to each other, and an intake rocker arm (62) and an exhaust rocker arm (63) that rotate with each of the rocker arm seats (61); the intake rocker arm (62) and the exhaust rocker arm (63) are connected to the other end of the corresponding push rod (5); the intake rocker arm (62) is connected to the corresponding two intake valves (21), and the exhaust rocker arm (63) is connected to the corresponding two exhaust valves (22).

2. The valve train system of a V-type two-cylinder four-valve engine according to claim 1, characterized in that, The center line connecting the two intake valves (21) on the intake rocker arm (62) and the two exhaust valves (22) on the exhaust rocker arm (63) is perpendicular to the axial direction of the camshaft (3).

3. The valve train system of a V-type two-cylinder four-valve engine according to claim 1, characterized in that, The tappet (4) is a hydraulic tappet or a mechanical tappet.

4. The valve train system of a V-type two-cylinder four-valve engine according to claim 1, characterized in that, On the same rocker arm seat (61), the intake valve (21) and the exhaust valve (22) arranged parallel to the axial direction of the camshaft (3) have an angle of 35~45°.

5. The valve train system of a V-type two-cylinder four-valve engine according to claim 1, characterized in that, On the same rocker arm seat (61), the included angle between the two push rods (5) is 5~20°.

6. The valve train system of a V-type two-cylinder four-valve engine according to claim 1, characterized in that, On one of the rocker arm mounts (61), the push rod (5) connected to the intake rocker arm (62) has an angle of 3~6° with the radial direction of the camshaft (3), and the push rod (5) connected to the exhaust rocker arm (63) has an angle of 4~8° with the radial direction of the camshaft (3). On another rocker arm mount (61), the push rod (5) connected to the intake rocker arm (62) has an angle of 3~6° with the radial direction of the camshaft (3), and the push rod (5) connected to the exhaust rocker arm (63) has an angle of 4~8° with the radial direction of the camshaft (3).

7. The valve train system of a V-type two-cylinder four-valve engine according to claim 1, characterized in that, The intake rocker arm (62) and exhaust rocker arm (63) are provided with rocker arm shafts between them and the corresponding rocker arm seats (61). The rocker arm shafts and the corresponding rocker arm seats (61) are clearance fit. The rocker arm seats (61) are fixed to the cylinder head (11) by bolts.

8. The valve train system of a V-type two-cylinder four-valve engine according to claim 7, characterized in that, The camshaft (3), the intake rocker arm (62), the exhaust rocker arm (63), and the rocker arm shaft are all made of steel.

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