CN113795656B - Variable compression ratio mechanism, engine and automobile - Google Patents
Variable compression ratio mechanism, engine and automobile Download PDFInfo
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- CN113795656B CN113795656B CN201980087088.6A CN201980087088A CN113795656B CN 113795656 B CN113795656 B CN 113795656B CN 201980087088 A CN201980087088 A CN 201980087088A CN 113795656 B CN113795656 B CN 113795656B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D15/00—Varying compression ratio
- F02D15/02—Varying compression ratio by alteration or displacement of piston stroke
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- General Engineering & Computer Science (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
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Abstract
The invention relates to a variable compression ratio mechanism, a variable compression ratio engine and an automobile, wherein the variable compression ratio mechanism comprises a piston, a crankshaft, an eccentric shaft with an eccentric wheel, an adjusting connecting rod rotatably arranged on a crank pin in the crankshaft, and an executing connecting rod and a driving connecting rod which are hinged at two ends of the adjusting connecting rod and are respectively hinged with the piston and the eccentric wheel, wherein the adjusting connecting rod comprises an upper rod part and a lower rod part which are fixedly connected together by a connecting piece, and when an included angle CA between a motion track of a hinge shaft center between the piston and the executing connecting rod and a connecting line between a crankshaft rotation center and a crank pin center is 30-40 degrees, a connecting line between hinge shaft centers at two ends of the executing connecting rod is parallel or nearly parallel to the axis of the connecting piece. The variable compression ratio mechanism can enable the cylinder explosion pressure transmitted to the adjusting connecting rod by the executing connecting rod to be transmitted along the axial direction of the connecting piece, and the tangential force borne by the connecting piece is reduced, so that the connecting piece can be prevented from being damaged, and the reliability of connection can be guaranteed.
Description
Technical Field
The invention relates to the technical field of engines, in particular to a variable compression ratio mechanism, and also relates to a variable compression ratio engine with the variable compression ratio mechanism and an automobile with the variable compression ratio engine.
Background
At present, engines used on automobiles are all fixed compression ratio engines, namely the compression ratio of the engine cannot change along with the load. However, the compression ratio should be determined as a compromise between dynamic performance, economy and post-combustion, which cannot be too large or too small, and at low speed and low load or partial load, if the compression ratio is too small, the combustible mixture cannot be sufficiently mixed, resulting in low combustion efficiency, high fuel consumption, and insufficient combustion emission, while at high speed and high load, if the compression ratio of the engine is too large, knocking is easily generated, if light, power output is affected, and if heavy, engine parts are damaged.
The multi-connecting rod type variable compression ratio mechanism is the only engine technology which achieves mass production conditions, and changes the compression ratio of an engine by continuously changing the top dead center position of the piston of the engine so as to meet different engine load requirements, so that the engine always works in the best working area, the dynamic property of the engine can be improved, the oil consumption can be reduced, the emission can be reduced, and the contradiction between the dynamic property, the economical efficiency and the emission can be well solved.
The existing multi-connecting-rod type variable compression ratio mechanism is generally composed of a piston, a crankshaft, an eccentric shaft with an eccentric wheel, an adjusting connecting rod rotating on a crank pin of the crankshaft, an executing connecting rod and a driving connecting rod hinged at two ends of the adjusting connecting rod and respectively hinged with the piston and the eccentric shaft.
Under the rotation of the eccentric shaft, the top dead center of the piston can be changed through the linkage of the multi-connecting-rod structure, so that the change of the compression ratio can be realized. However, in the existing variable compression ratio mechanism with a multi-link structure, because the swing angle of the link is large, the abrasion loss of the link is large, the abrasion is serious, and the reliability of the mechanism is influenced after a long time.
In addition, the adjusting link is generally formed in a separate structure in an expansion-breaking manner and is connected to the adjusting link by a connecting member such as a connecting member. During the operation of the engine, the combustion and explosion force in the cylinder borne by the piston is transmitted to the multi-connecting-rod structure, so that the stress on the connecting piece in the adjusting connecting rod is large, particularly the connecting piece can bear large tangential force, the connecting piece is easy to damage, the connection failure is further caused, and the normal operation of the engine is influenced.
Disclosure of Invention
In view of the above, the present invention is directed to a variable compression ratio mechanism capable of reducing the tangential force of a link in an adjusting link during engine operation.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a variable compression ratio mechanism comprises a piston arranged in an engine cylinder body in a sliding mode, a crankshaft arranged in the engine cylinder body in a rotating mode, an eccentric shaft with an eccentric wheel, an adjusting connecting rod arranged on a crank pin in the crankshaft in a rotating mode, and an executing connecting rod and a driving connecting rod which are hinged to two ends of the adjusting connecting rod and are respectively hinged to the piston and the eccentric wheel;
the adjusting connecting rod comprises an upper rod part and a lower rod part which are fixedly connected together by a connecting piece, a joint surface between the upper rod part and the lower rod part is orthogonal to the axis of the connecting piece, a mounting hole for the crank pin to pass through is formed between the upper rod part and the lower rod part in a surrounding manner, and the connecting pieces are two connecting pieces which are respectively arranged on the opposite sides of the mounting Kong Liangxiang;
the distance L1 between the centers of hinge shafts at two ends of the execution connecting rod, the distance L2 between the centers of hinge shafts between the crank pin and the adjustment connecting rod and the execution connecting rod, the distance L3 between the centers of hinge shafts between the crank pin and the adjustment connecting rod and the drive connecting rod, the distance L4 between the centers of hinge shafts at two ends of the drive connecting rod, and the distance e between the movement track of the center of a hinge shaft between the piston and the execution connecting rod and the perpendicular line of the rotation center of the crankshaft are set to be 30-40 degrees, and the connecting line between the centers of hinge shafts at two ends of the execution connecting rod is parallel or nearly parallel to the axis of the connecting piece.
Further, the connecting piece is a bolt.
Furthermore, the piston and the execution connecting rod are hinged and connected through a connecting pin, and the execution connecting rod, the driving connecting rod and the adjusting connecting rod are hinged and connected through a connecting pin.
Furthermore, a bushing pressed in the corresponding pin hole is arranged at each connecting pin.
Further, the upper rod part and the lower rod part are formed by a powder forging process.
Furthermore, a meshing part which is used for forming mutual meshing between the upper rod part and the lower rod part is arranged at the position of the combining surface.
Further, the snapping part comprises a positioning protrusion integrally configured on the upper rod part and a groove configured on the lower rod part corresponding to the positioning protrusion, and the positioning protrusion is embedded in the groove.
Furthermore, the occlusion part comprises pin holes correspondingly arranged on the upper rod part and the lower rod part, and positioning pins with two ends respectively inserted in the pin holes on the upper rod part and the lower rod part.
Furthermore, the occlusion part comprises a positioning groove, a positioning sleeve ring and a positioning convex head, wherein the positioning groove is formed in the upper rod part by surrounding the connecting piece, the positioning sleeve ring is embedded into the positioning groove and sleeved on the connecting piece, the positioning sleeve ring is provided with the positioning convex head, the positioning hole is formed in the lower rod part by surrounding the connecting piece, the positioning hole is matched with the positioning convex head, and the positioning convex head is embedded into the positioning hole.
Further, the swing angle of the actuating link is set to be less than 30 ° with the actuating link and the inter-piston hinge shaft as swing centers, and the swing angle of the driving link is set to be less than 27 ° with the eccentric as swing centers.
Further, a distance L1 between hinge shaft centers at both ends of the actuating link, a distance L2 between a center of the crank pin and a center of the hinge shaft between the adjusting link and the actuating link, a distance L3 between a center of the crank pin and a center of the hinge shaft between the adjusting link and the actuating link, and a distance L4 between hinge shaft centers at both ends of the actuating link are set to satisfy the following relations: L1/L3= L4/L2.
Further, a distance L3 between the center of the crank pin and the center of the hinge shaft between the adjusting link and the driving link, a distance L4 between the centers of the hinge shafts at both ends of the driving link, a distance L5 between the center of the eccentric wheel and the center of rotation of the crankshaft, and a distance r between the center of rotation of the crankshaft and the center of the crank pin are set to satisfy (L4) 2 +L3 2 -r 2 ）/L5 2 The value of (b) is between 0.9 and 1.1.
Compared with the prior art, the invention has the following advantages:
(1) According to the variable compression ratio mechanism, when the included angle CA is 30-40 degrees, namely the crankshaft rotates to the position near the maximum explosion pressure of the cylinder, the axis of the execution connecting rod is parallel or nearly parallel to the axis of the connecting piece, so that the explosion pressure of the cylinder transmitted to the adjusting connecting rod by the execution connecting rod is transmitted along the axial direction of the connecting piece, the tangential force borne by the connecting piece is reduced, the damage to the connecting piece can be avoided, and the connection reliability can be guaranteed.
In addition, the engaging part is arranged at the joint surface between the upper rod part and the lower rod part in the adjusting connecting rod, and when the explosion pressure of the cylinder is less than the maximum value, the engaging part can bear the tangential force borne by the connecting piece, so that the tangential force of the connecting piece can be reduced, the damage of the connecting piece is avoided, and the connection reliability of the connecting piece can be guaranteed.
(2) The variable compression ratio mechanism of the invention can reduce the friction loss and the reciprocating inertia force of the connecting rod by limiting the swinging angle of the connecting rod during work, thereby reducing the abrasion of the connecting rod.
In addition, the invention can realize the reduction of the swing angle of the connecting rod during the work by setting the distance relationship between the components, thereby reducing the friction loss of the connecting rod due to the reduction of the swing angle, reducing the swing acceleration of the connecting rod to reduce the reciprocating inertia force of the connecting rod, and reducing the abrasion of the connecting rod.
It is another object of the present invention to provide a variable compression ratio engine including an engine block, and further including a variable compression ratio mechanism as described above provided in the engine block.
It is a further object of the present invention to provide an automobile including the variable compression ratio engine described above.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic structural view of a variable compression ratio mechanism according to a first embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an adjusting link according to a first embodiment of the present invention;
fig. 3 is a schematic structural view of an engaging portion formed by the positioning protrusion and the groove according to a first embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an engaging portion formed by a positioning pin and a pin hole according to a first embodiment of the present invention;
fig. 5 is a schematic structural view of an engaging portion formed by the positioning collar and the positioning hole according to the first embodiment of the present invention;
FIG. 6 is a diagram illustrating the relationship between the distance and the angle between the components of the variable compression ratio mechanism according to the first embodiment of the present invention;
FIG. 7 is a schematic view of an angle adjustment link according to one embodiment of the present invention;
fig. 8 is a schematic swinging diagram of the actuating link according to the first embodiment of the present invention (the structure of the dotted line in the figure is a diagram illustrating the actuating link swinging to the other extreme position);
fig. 9 is a schematic diagram of the swing of the driving link according to the first embodiment of the present invention (the dotted line structure in the figure is the driving link when the driving link swings to the other extreme position);
description of reference numerals:
1-piston, 2-actuating link, 3-adjusting link, 4-crankshaft, 5-driving link, 6-eccentric shaft, 7-eccentric wheel, 8-link, 9-locating pin, 10-locating collar, 11-piston connecting pin, 12-actuating link connecting pin, 13-driving link connecting pin, 14-crank pin;
101-positioning raised heads;
301-upper rod part, 3011-positioning bulge, 302-lower rod part, 303-mounting hole and 304-connecting pin hole of adjusting connecting rod.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Example one
The present embodiment relates to a variable compression ratio mechanism which is a multi-link type variable compression ratio mechanism, and as shown in fig. 1, the mechanism includes a piston 1 slidably provided in an engine block, not shown in the drawings, a crankshaft 4 rotatably provided in the engine block and an eccentric shaft 6 having an eccentric 7, an adjusting link 3 rotatably provided on a crank pin in the crankshaft 4, and an actuating link 2 and a driving link 5 hinged to both ends of the adjusting link 3 and hinged to the piston 1 and the eccentric 7, respectively.
As shown in fig. 2, the structure of the adjusting link 3 specifically includes an upper rod portion 301 and a lower rod portion 302 which are fixedly connected together by a connecting piece 8, the structures of the upper rod portion 301 and the lower rod portion 302 are preferably set to be the same, and both can be formed by a powder forging process, and a joint surface M is formed between the two due to connection, and the joint surface M is also orthogonally arranged with respect to the axis of the connecting piece 8. Further, a mounting hole 303 for passing a crank pin of the crankshaft 4 is also formed between the upper rod portion 301 and the lower rod portion 302, that is, the adjusting link 3 is rotatably mounted on the crank pin through the mounting hole 303, and the connecting members 8 are respectively provided at two opposite sides of the mounting hole 303.
In this embodiment, the connecting member 8 for fixedly connecting the two rod portions of the adjusting connecting rod 3 is preferably a bolt, and both the upper rod portion 301 and the lower rod portion 302 as the main structure of the adjusting connecting rod 3 can be formed by a powder forging process, and after the connecting member 8 is connected, a structure with central symmetry is formed between the upper rod portion 301 and the lower rod portion 302, i.e., relative to the center of the mounting hole 303. The upper rod part 301 and the lower rod part 302 are respectively provided with a through adjusting connecting rod pin hole 304, and the actuating connecting rod 2 and the driving connecting rod 5 are respectively connected with the adjusting connecting rod pin holes 304 on the upper rod part 301 and the lower rod part 302.
In addition, in the present embodiment, an engaging portion for engaging the upper rod portion 301 and the lower rod portion 302 with each other is also provided at the upper rod portion 301 and the joint surface M. The engagement part can share the component force of the explosion pressure along the joint surface when the explosion pressure in the cylinder is transmitted to the adjusting connecting rod 3 through the actuating connecting rod 2 in the running process of the engine, so that the tangential force born by the connecting piece 8 formed by the bolt can be reduced, and the aim of avoiding the damage of the bolt can be fulfilled.
Structurally, as a possible structure, as shown in fig. 3, for example, the engaging portion includes a positioning protrusion 3011 integrally formed on the upper rod portion 301, and a groove is formed on the lower rod portion 302 corresponding to the positioning protrusion 3011, and the positioning protrusion 3011 is inserted into the groove, thereby achieving the mutual engagement between the upper rod portion 301 and the lower rod portion 302.
As another possible structure, as shown in fig. 4, the engaging portion may also include pin holes correspondingly formed on the upper rod portion 301 and the lower rod portion 302, and positioning pins 9 respectively inserted into the pin holes formed on the upper rod portion 301 and the lower rod portion 302 at two ends. Thus, the upper rod portion 301 and the lower rod portion 302 can be engaged with each other by inserting both ends of the positioning pin 9 into the pin holes of the two rod portions.
It should be noted that the shape of the positioning protrusion 3011 is not limited to that shown in fig. 3, and the matching groove may be any shape that can make the two rods assume a snap-fit shape. Meanwhile, the positioning pin 9 is also the same as the positioning protrusion 3011, and the cross-sectional shape of the pin hole matched with the positioning pin is not limited, so that the snap function can be realized. In addition, for the positioning protrusions 3011 or the positioning pins 9, the number of the positioning protrusions and the arrangement rule at the joint surface M can be selected according to the shape and the size of the joint surface between the upper rod portion 301 and the lower rod portion 302, and the positioning protrusions and the positioning pins do not affect the structural strength of the joint surface between the two rod portions, and can ensure that a required biting force is obtained.
Of course, in addition to the positioning protrusions 3011 and the positioning pins 9, as another possible structure, as shown in fig. 5, the engaging portion of the present embodiment may further include a positioning groove formed on the upper rod portion 301 around the connecting member 8, a positioning collar 10 having a positioning protrusion 101 embedded in the positioning groove and sleeved on the connecting member 8, and a positioning hole formed on the lower rod portion 302 around the connecting member 8. The positioning holes are arranged in a shape, number and position arrangement which is matched to the positioning projections 101 on the positioning collar 10, so that the positioning projections 101 can be inserted into the positioning holes, and the two rod parts can be engaged with each other.
In addition to the above-described adjusting link 3 in the present embodiment, other components such as the actuating link 2, the driving link 5, and others can be referred to in the related art of the engine. In a preferred embodiment, the piston 1 and the actuating link 2, the actuating link 2 and the adjusting link 3, and the driving link 5 and the adjusting link 3 are hinged by connecting pins. At this time, the piston 1 and the actuating link 2 are hinged to each other by a piston connecting pin 11, and the adjusting link 3 is hinged to the actuating link 2 and the driving link 5 by an actuating link connecting pin 12 and a driving link connecting pin 13, respectively. In the embodiment, the connecting pins can be respectively provided with the bushings which are pressed in the corresponding pin holes, so that the abrasion of the connecting pins and the connecting rod structures is reduced.
When the variable compression ratio mechanism of the embodiment works, the eccentric shaft 6 in the variable compression ratio mechanism can be driven to rotate by a motor arranged on an engine cylinder body through a speed reducer, the rotation of the eccentric shaft 6 enables the supporting point of the driving connecting rod 5 to move up and down through the eccentric wheel 7, the change of the supporting point of the driving connecting rod 5 can change the upper dead point of the piston 1 through the linkage of the adjusting connecting rod 3 and the executing connecting rod 2, and therefore the adjustment of the compression ratio of the engine can be realized.
Further, referring to fig. 6, for each component in the variable compression ratio mechanism, the present embodiment also makes a distance L1 between the centers of the hinge shafts at both ends of the actuating link 2, i.e., a distance between the center of the piston connecting pin 11 and the center of the actuating link connecting pin 12, a distance L2 between the center of the crank pin 14 and the centers of the hinge shafts between the adjusting link 3 and the actuating link 2, i.e., a distance between the center of the crank pin 14 and the centers of the hinge shafts between the adjusting link 3 and the actuating link 5, i.e., a distance L3 between the center of the crank pin 14 and the centers of the hinge shafts between the driving link 3 and the actuating link 5, i.e., a distance between the center of the crank pin 14 and the center of the driving link connecting pin 13, a distance L4 between the centers of the hinge shafts at both ends of the driving link 5, i.e., a distance between the centers of the piston connecting pin 11 and the actuating link 2 and a perpendicular line e between the centers of rotation of the crank shaft 4, set such that the five distances are approximately parallel to the axis of the connecting rod 3 and the adjusting link 8 or the connecting rod connecting pin 8, when the angle CA between the centers of the hinge shafts between the piston connecting pin 4 and the crank pin 14 is 30 ° -and the actuating link.
Specifically, as shown in fig. 7, when the above-mentioned angle CA is 30 ° to 40 °, for example, 32 °, 35 °, 36.5 ° or 38 °, the crankshaft 4 in the engine is rotated until the fuel explosion pressure in the engine block is in the vicinity of the maximum value, at which time the above-mentioned distances L1, L2, L3, L4 and e make the line connecting the center of the piston connecting pin 11 and the center of the actuator connecting rod connecting pin 12 parallel or nearly parallel to the axis of the connecting member 8, that is, the angle A7+ A8 is equal to or nearly 90 °. Therefore, when the explosion pressure of the cylinder is transmitted to the adjusting connecting rod 3 through the actuating connecting rod 2, because the actuating connecting rod 2 is parallel or nearly parallel to the bolt, the direction of the force FB transmitted to the adjusting connecting rod 3 is also parallel or nearly parallel to the bolt, so that the stress of the bolt is mainly the force F7y along the axial direction of the bolt, and the tangential force F7x vertical to the axial direction of the bolt is smaller, thereby achieving the effect of avoiding the damage of the bolt.
The angle A7 is an angle between a plane of the joint surface of the adjusting link 3 and a line connecting the center of the actuating link connecting pin 11 and the center of the driving link connecting pin 12, and the angle A8 is an angle between a line connecting the center of the actuating link connecting pin 11 and the center of the driving link connecting pin 12 and a line connecting the centers of the piston connecting pin 11 and the actuating link connecting pin 12.
In addition, when the crankshaft 4 rotates to make CA at other angles than the above-mentioned 30 ° -40 °, the deviation of the sum of the angles A7 and A8 is larger than 90 °, so that the direction of the force FB transmitted from the actuating link 2 to the adjusting link 3 forms a certain angle with the axial direction of the bolt, and can be decomposed into two force components along the axial direction and the tangential direction of the bolt (i.e. along the extension direction of the joint surface M). In this case, the design of the engaging portion of the adjusting link 3, which is received at the joint surface M between the upper rod portion 301 and the lower rod portion 302, can share the component force transmitted to the joint surface between the upper rod portion 301 and the lower rod portion 302 through the positioning protrusion 3011, the positioning pin 9 or the positioning protrusion 101 on the positioning collar 10, so that the tangential force borne by the bolt can be reduced, and the purpose of avoiding the bolt from being damaged can be achieved.
The variable compression ratio mechanism of the embodiment can reduce the tangential force applied to the connecting piece 8 formed by the bolts by making the driving connecting rod 2 and the bolt axially parallel and arranging the occlusion part on the adjusting connecting rod 3 through the two designs, thereby avoiding the damage of the connecting piece 8, and selecting the bolts into smaller specifications, thereby having good practicability.
Further, in the variable compression ratio mechanism of the present embodiment, the pivot angle of the actuator connecting rod 2 is set to be less than 30 ° with the hinge shaft between the actuator connecting rod 2 and the piston 1, that is, the piston connecting pin 11, as the pivot center, and the pivot angle of the drive connecting rod 5 is set to be less than 27 ° with the eccentric 7 as the pivot center. By limiting the swing angle of the two connecting rods during working, the friction loss and the reciprocating inertia force of the connecting rods can be reduced, and the effect of reducing the abrasion of the connecting rods can be achieved.
Based on the above setting of the pivot angle, as an embodiment, referring to fig. 6 in combination with fig. 8, for each component in the variable compression ratio mechanism, taking the actuating link 2 that swings during operation as an example, the distance L1 between the centers of hinge shafts at both ends of the actuating link 2, i.e., the distance between the center of the piston connecting pin 11 and the center of the actuating link connecting pin 12, the distance L2 between the center of the crank pin 14 and the center of a hinge shaft between the adjusting link 3 and the actuating link 2, i.e., the distance between the center of the crank pin 14 and the center of a hinge shaft between the actuating link 12, the distance L3 between the center of the crank pin 14 and the center of a hinge shaft between the adjusting link 3 and the driving link 5, i.e., the distance L4 between the centers of hinge shafts at both ends of the driving link 5, i.e., the distance between the center of a hinge shaft between the driving link connecting pin 13 and the center of the eccentric 7, is set to satisfy L1/L3L 4 = L4/L2.
Due to the arrangement of the relation, when the execution connecting rod 2 works, the included angle beta between the limit positions (2 a and 2 b) at two sides to which the execution connecting rod swings can be within 30 degrees, and the swinging angle of the execution connecting rod 2 is small, so that the friction loss of the execution connecting rod in swinging can be reduced, the inertia force of reciprocating swinging of the execution connecting rod can be reduced, and the purpose of reducing the abrasion is further achieved. When the above relation L1/L3= L4/L2 is not satisfied, the larger the deviation between L1/L3 and L4/L2 is, the larger the swing angle β of the actuating link 2 becomes, and at this time, the wear amount due to the swing is greatly increased.
Similar to the above-mentioned setting of the swing angle of the actuating link 2, for the setting of the swing angle of the actuating link 5 which is also in the swing shape during operation, as a practical implementation, the present embodiment is combined with the setting of the center of the crank pin 14 and the center of the hinge shaft between the adjusting link 3 and the actuating link 2 as shown in fig. 9A distance L3 between the centers of the crank pins 14 and the centers of the drive link connecting pins 13, a distance L4 between the centers of the hinge shafts at both ends of the drive link 5, a distance between the centers of the drive link connecting pins 13 and the eccentric 7, a distance L5 between the centers of the eccentric 7 and the center of rotation of the crank shaft 4, and a distance r between the center of rotation of the crank shaft 4 and the center of the crank pins 14 are set to satisfy (L4) 2 +L3 2 -r 2 ）/L5 2 The value of (A) is between 0.9 and 1.1.
At this time, the expression (L4) composed of the above distances 2 +L3 2 -r 2 ）/L5 2 The value of (b) may be, for example, 0.9, 0.95, 1.0, 1.02, 1.05, 1.08 or 1.1. The value of the expression is in the interval, so that the included angle alpha between the limit positions (5 a and 5 b) at two sides of the swing of the driving connecting rod 5 can be within 27 degrees when the driving connecting rod 5 works, the swing angle of the driving connecting rod 5 is small, the friction loss of the driving connecting rod 5 in the swing can be reduced, the inertia force of the reciprocating swing of the driving connecting rod can be reduced, and the purpose of reducing the abrasion is achieved. When the value of the above expression is not within the above numerical range, the more it exceeds the range, the larger the swing angle α of the drive link 5 becomes, and at this time, the amount of wear due to the swing is greatly increased.
The variable compression ratio mechanism of the present embodiment can reduce the friction loss and the reciprocating inertia force of the actuator link 2 and the drive link 5 during operation by limiting the swing angles of the two links, thereby reducing the wear thereof and improving the service life of the two link structures, and thus has excellent practicability.
Example two
The present embodiment relates to a variable compression ratio engine that includes an engine block, and further includes a variable compression ratio mechanism as in the first embodiment provided in the engine block.
The engine of the present embodiment, by using the variable compression ratio mechanism of the first embodiment, can reduce the wear of the actuator link 2 and the drive link 5, and can improve the service life of the two link structures, thereby having excellent practicability.
The engine of the embodiment adopts the variable compression ratio mechanism in the first embodiment, so that the tangential force borne by the connecting piece formed by the bolt in the adjusting connecting rod can be reduced, the connecting piece can be prevented from being damaged, the connection reliability can be guaranteed, and the practicability is good.
EXAMPLE III
The present embodiment relates to an automobile including a variable compression ratio engine as in the second embodiment.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (13)
1. A variable compression ratio mechanism comprises a piston (1) arranged in an engine cylinder in a sliding way, a crankshaft (4) arranged in the engine cylinder in a rotating way and an eccentric shaft (6) with an eccentric wheel (7), an adjusting connecting rod (3) arranged on a crank pin (14) in the crankshaft (4) in a rotating way, and an executing connecting rod (2) and a driving connecting rod (5) which are hinged at two ends of the adjusting connecting rod (3) and are respectively hinged with the piston (1) and the eccentric wheel (7); the method is characterized in that:
the adjusting connecting rod (3) comprises an upper rod part (301) and a lower rod part (302) which are fixedly connected together through a connecting piece (8), a joint surface between the upper rod part (301) and the lower rod part (302) is orthogonal to the axis of the connecting piece (8), a mounting hole (303) for the crank pin (14) to pass through is formed between the upper rod part (301) and the lower rod part (302), and the connecting piece (8) is divided into two parts which are arranged on two opposite sides of the mounting hole (303);
and the distance L1 between the centers of the hinge shafts at the two ends of the execution connecting rod (2), the distance L2 between the center of the crank pin (14) and the center of the hinge shaft between the adjustment connecting rod (3) and the execution connecting rod (2), the distance L3 between the center of the crank pin (14) and the center of the hinge shaft between the adjustment connecting rod (3) and the drive connecting rod (5), the distance L4 between the centers of the hinge shafts at the two ends of the drive connecting rod (5), and the perpendicular distance e between the movement locus of the center of the hinge shaft between the piston (1) and the execution connecting rod (2) and the rotation center of the crank shaft (4) and the rotation center of the crank pin (14) are set to be parallel or nearly parallel to the axis of the connecting piece (8) when the included angle CA between the movement locus of the center of the hinge shaft between the piston (1) and the execution connecting rod (2) and the connecting line between the rotation center of the crank shaft (4) and the center of the crank pin (14) is 30-40 degrees;
the pivot angle of the actuating connecting rod (2) is set to be lower than 30 degrees by taking a hinge shaft between the actuating connecting rod (2) and the piston (1) as a pivot center, and the pivot angle of the driving connecting rod (5) is set to be smaller than 27 degrees by taking the eccentric wheel (7) as a pivot center.
2. The variable compression ratio mechanism according to claim 1, characterized in that: the connecting piece (8) is a bolt.
3. The variable compression ratio mechanism according to claim 1, characterized in that: the piston (1) and the execution connecting rod (2), the driving connecting rod (5) and the adjusting connecting rod (3) are hinged through connecting pins.
4. The variable compression ratio mechanism according to claim 3, characterized in that: and bushings which are pressed in the corresponding pin holes are respectively arranged at the connecting pins.
5. The variable compression ratio mechanism according to claim 1, characterized in that: the upper rod part (301) and the lower rod part (302) are formed by a powder forging process.
6. The variable compression ratio mechanism according to any one of claims 1 to 5, characterized in that: and the joint surface is provided with a meshing part which is used for forming mutual meshing between the upper rod part (301) and the lower rod part (302).
7. The variable compression ratio mechanism according to claim 6, characterized in that: the occluding part comprises a positioning protrusion (3011) integrally constructed on the upper rod part (301) and a groove constructed on the lower rod part (302) corresponding to the positioning protrusion (3011), and the positioning protrusion (3011) is embedded in the groove.
8. The variable compression ratio mechanism according to claim 6, characterized in that: the occlusion part comprises pin holes correspondingly arranged on the upper rod part (301) and the lower rod part (302), and positioning pins (9) with two ends respectively arranged in the pin holes on the upper rod part (301) and the lower rod part (302).
9. The variable compression ratio mechanism according to claim 6, characterized in that: the occlusion part comprises a positioning groove, a positioning sleeve ring (10) and a positioning raised head (101), wherein the positioning groove is formed in the upper rod part (301) around the connecting piece (8), the positioning sleeve ring is embedded into the positioning groove and sleeved on the connecting piece (8), the positioning sleeve ring is provided with the positioning raised head (101), the positioning hole is formed in the lower rod part (302) around the connecting piece (8), the positioning hole is matched with the positioning raised head (101) and the positioning raised head (101) is embedded into the positioning hole.
10. The variable compression ratio mechanism according to claim 1, characterized in that: execute distance L1 between connecting rod (2) both ends articulated shaft center, crank pin (14) center with adjust connecting rod (3) and execute distance L2 between connecting rod (2) articulated shaft center, crank pin (14) center with adjust connecting rod (3) and drive connecting rod (5) between articulated shaft center distance L3, and drive connecting rod (5) both ends articulated shaft center between distance L4 is set up to satisfy following relational expression: L1/L3= L4/L2.
11. The variable compression ratio mechanism according to claim 1, characterized in that: the crank pin (14) center and the an adjusting link (3) and a drive link (c)5) A distance L3 between the centers of the hinge shafts, a distance L4 between the centers of the hinge shafts at both ends of the driving link (5), a distance L5 between the center of the eccentric wheel and the center of the crank shaft, and a distance r between the center of the crank shaft and the center of the crank pin are set to satisfy (L4) 2 +L3 2 -r 2 ）/L5 2 The value of (A) is between 0.9 and 1.1.
12. A variable compression ratio engine comprising an engine block, characterized in that: further comprising a variable compression ratio mechanism according to any one of claims 1 to 11 provided in the engine block.
13. An automobile, characterized in that: comprising a variable compression ratio engine according to claim 12.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811646188.1 | 2018-12-30 | ||
| CN201811646189.6 | 2018-12-30 | ||
| CN201811646189.6A CN110657024A (en) | 2018-12-30 | 2018-12-30 | Variable compression ratio mechanism and engine |
| CN201811646188.1A CN110671199B (en) | 2018-12-30 | 2018-12-30 | Variable compression ratio mechanism and engine |
| PCT/CN2019/129241 WO2020140843A1 (en) | 2018-12-30 | 2019-12-27 | Variable compression ratio mechanism, engine and automobile |
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| Publication Number | Publication Date |
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| CN113795656A CN113795656A (en) | 2021-12-14 |
| CN113795656B true CN113795656B (en) | 2023-01-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201980087088.6A Active CN113795656B (en) | 2018-12-30 | 2019-12-27 | Variable compression ratio mechanism, engine and automobile |
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| Country | Link |
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| CN (1) | CN113795656B (en) |
| WO (1) | WO2020140843A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114893295B (en) * | 2022-05-25 | 2023-07-04 | 一汽解放汽车有限公司 | Engine connecting rod and engine |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4038959B2 (en) * | 2000-05-09 | 2008-01-30 | 日産自動車株式会社 | Variable compression ratio mechanism of internal combustion engine |
| JP4175110B2 (en) * | 2002-12-27 | 2008-11-05 | 日産自動車株式会社 | Internal combustion engine with variable compression ratio mechanism |
| JP4387770B2 (en) * | 2003-11-19 | 2009-12-24 | 日産自動車株式会社 | Internal combustion engine |
| JP2009108708A (en) * | 2007-10-26 | 2009-05-21 | Nissan Motor Co Ltd | Link geometry for multi-link engine |
| CN101701548B (en) * | 2009-11-20 | 2012-09-05 | 天津大学 | Engine with adjustable compression ratio |
| DE102011104531A1 (en) * | 2011-06-18 | 2012-12-20 | Audi Ag | Internal combustion engine |
| DE102013021980A1 (en) * | 2013-12-20 | 2015-06-25 | Audi Ag | Coupling link for a multi-link crank drive and multi-link crank drive |
| CN206889097U (en) * | 2017-05-17 | 2018-01-16 | 广州汽车集团股份有限公司 | Variable compression ratio device and variable compression ratio engine |
| CN107023386B (en) * | 2017-05-17 | 2022-12-30 | 广州汽车集团股份有限公司 | Variable compression ratio device and variable compression ratio engine |
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2019
- 2019-12-27 WO PCT/CN2019/129241 patent/WO2020140843A1/en active Application Filing
- 2019-12-27 CN CN201980087088.6A patent/CN113795656B/en active Active
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| WO2020140843A1 (en) | 2020-07-09 |
| CN113795656A (en) | 2021-12-14 |
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