A method for improving the effective thermal efficiency of the engine and a power transmission mechanism produced using this method

Abstract

Power transmission mechanism for improving the effective thermal efficiency of a motor, wherein the power transmission mechanism comprises: - a first crankshaft (14) with a first crankshaft axis and a first crank (15), - a second crankshaft (22) with a second crankshaft axis and a second crank (19), - a first crank connecting rod (17) which is articulated at a first end to an end of the first crank (15) furthest from the crankshaft axis, thereby establishing a pivot axis between the first crank (15) and the first crank connecting rod (17), - a second crank connecting rod (18) which is articulated at a first end to an end of the second crank (19) furthest from the crankshaft axis, thereby establishing a pivot axis between the second crank (19) and the second crank connecting rod (18), - a connecting end axle to the first end of which a second end of the first crank connecting rod (17) is articulated, thereby defining a pivot axis between the connecting end axle and the first crank connecting rod (17), wherein a second end of the second crank connecting rod (18) is articulated to a second end of the connecting end axle, thereby defining a pivot axis between the connecting end axle and the second crank connecting rod (18), - a piston rod (12) with a first end that is attached to the connecting end axis centrally between its two pivot axes, characterized by the fact that a displacement mechanism coefficient σ pz between 0.60 and 0.75 where the offset mechanism coefficient σ pz equal to the quotient of an eccentricity e divided by the difference between distances L and R, where L, R and e denote the following: - L is a distance between the two pivot axes of the first crank connecting rod (17), wherein a distance between the two pivot axes of the second crank connecting rod (18) is equal; - R is a distance between the first crankshaft axis and the pivot axis between the first crank (15) and the first crank connecting rod (17), wherein a distance between the second crankshaft axis and the pivot axis between the second crank (19) and the second crank connecting rod (18) is equal to R; - the eccentricity e is a distance equal to half the difference between the distances La and Lv, where La is a distance between the two crankshaft axes and Lv is a distance between the two pivot axes of the connecting end axis.

Description

Technical area

[0001] The invention relates to a power transmission mechanism. Background technology

[0002] DE 10 2015 013 489 A1 describes an internal combustion engine with a double crank drive and variable compression. Power is transferred from the piston to the crank drive via a piston rod attached to the piston, which moves linearly in line with the piston's movement, and a connecting rod connected to this piston rod and the double crank drive. To adjust the compression, the connecting rod's engagement point on the piston rod can be adjusted even during engine operation.

[0003] US Patent No. 2,417,910 describes an engine with a power transmission mechanism featuring a dual crankshaft design. The crankshafts are arranged symmetrically on either side of the piston rod to balance lateral thrust on the piston. This reduces lateral wear and allows the use of envelope piston valves. The crankshafts are synchronized by gears, resulting in more effective power transmission, as the piston's downstroke extends over a larger arc angle of the crankshafts than the upstroke.

[0004] WO 90 / 01647 A1 describes a crank mechanism in which the piston's movement is slower near top dead center than near bottom dead center. The expansion and intake strokes occur at the same rotational speed over a longer period of time than the compression and exhaust strokes. During operation, there are no closing forces that could press the piston against the cylinder wall.

[0005] DE 102 47 197 A1 describes a reciprocating internal combustion engine with at least one cylinder. An intake valve and an exhaust valve are arranged in the cylinder head. A piston in the cylinder has a shaft that is guided linearly and sealed by a partition on the side of the piston facing away from the working chamber. This shaft connects the piston to a crank mechanism containing a crankshaft. The space between the piston and the partition forms a fresh charge chamber, which is connected to the environment via a valve device. There is also an overflow device that opens a transfer path from the fresh charge chamber to the working chamber when the piston is near its bottom dead center.

[0006] Currently, all types of disclosed engine power transmission mechanisms convert the reciprocating motion of the piston into rotational motion through the crank connecting rod mechanism and the crankshaft, and the crankshaft is driven by the piston connecting rod to perform work. These structures are divided into single crankshaft structure and double crankshaft structure. They are also divided into offset structure and non-offset structure. Although these engine power transmission mechanisms with these structures have their own advantages, their disadvantages still exist. For example, an alternating side pressure exists between the piston and the air cylinder wall of an offset engine with a single crankshaft structure, which affects the frictional power consumption between the piston and the air cylinder liner.Statistical data show that frictional power consumption accounts for about 75% of the engine's mechanical loss, and the frictional power consumption between the air cylinder liner and the piston ring accounts for 50% of the piston connecting rod system. Therefore, to reduce the piston's side thrust, the crankshaft offset arrangement is commonly used. However, from the disclosed technical solution, it can be seen that the offset crankshaft structure can generally eliminate the side thrust between the piston and the engine's air cylinder wall, reducing friction and vibration. Since experts in the field believe that the larger the ratio of power stroke to crankshaft rotation angle, the more work is done, the crankshaft connecting rod mechanism rotates only in the positive offset direction.The engine power transmission mechanisms arranged in the form of a positive offset result in a lower increase in the effective thermal efficiency of the engine. Summary of the invention

[0007] The purpose of the invention is to provide a power transmission mechanism for improving the effective thermal efficiency of an engine, which can overcome the deficiency of the prior art.

[0008] To achieve the above purpose, the invention provides the technical solution as defined in the appended claims.

[0009] The power transmission mechanism according to the invention for improving an effective thermal efficiency of an engine comprises the following: - a first crankshaft with a first crankshaft axis and a first crank, - a second crankshaft with a second crankshaft axis and a second crank, - a first crank connecting rod, which is articulated at a first end to an end of the first crank remote from the crankshaft axis, thereby defining a pivot axis between the first crank and the first crank connecting rod, - a second crank connecting rod, which is articulated at a first end to an end of the second crank remote from the crankshaft axis, thereby defining a pivot axis between the second crank and the second crank connecting rod, - a connecting end axis to whose first end a second end of the first crank connecting rod is articulated, whereby a pivot axis is defined between the connecting end axis and the first crank connecting rod, wherein a second end of the second crank connecting rod is articulated at a second end of the connecting end axis, whereby a pivot axis is defined between the connecting end axis and the second crank connecting rod, - a piston rod having a first end fixed to the connecting end axis centrally between its two pivot axes.

[0010] The displacement mechanism coefficient σ pz is between 0.60 and 0.75, where the displacement mechanism coefficient σ pz is equal to the quotient of an eccentricity e divided by the difference of distances L and R, where L, R and e denote the following: - L is a distance between the two pivot axes of the first crank connecting rod, wherein a distance between the two pivot axes of the second crank connecting rod is the same; - R is a distance between the first crankshaft axis and the pivot axis between the first crank and the first crank connecting rod, wherein a distance between the second crankshaft axis and the pivot axis between the second crank and the second crank connecting rod is equal to R; - the eccentricity e is a distance equal to half the difference between the distances La and Lv, where La is a distance between the two crankshaft axes and Lv is a distance between the two pivot axes of the connecting end axis.

[0011] An embodiment of the power transmission mechanism provides that it comprises a housing, wherein an air cylinder is installed in the housing, wherein a piston is installed in the air cylinder, wherein a second end of the piston rod is connected to the piston, wherein the two ends of the connecting end axis are each connected to a crank connecting rod mechanism, wherein the two crank connecting rod mechanisms have the same structure and are arranged symmetrically on both sides of the air cylinder, wherein the eccentricity e is greater than the crank radius R, wherein the crankshaft axes are each perpendicular to an air cylinder center line, wherein an imaginary connecting line between the two crankshaft axes is located between the connecting end axis and the second end of the piston rod.

[0012] A further development of this power transmission mechanism provides that the first crankshaft rotates clockwise and the second crankshaft rotates counterclockwise.

[0013] The inventive method goes beyond the concept that those skilled in the art set the offset mechanism coefficient in the negative offset mechanism to less than or equal to 0.1. Those skilled in the art have long believed that the offset coefficient in the negative offset mechanism of various engine power transmission mechanisms cannot be greater than 0.1. This concept is based on the fact that the larger the ratio of power stroke to crankshaft rotation angle, the more work is done. However, the invention states that when the crankshaft rotates in the negative offset direction, the limitation that the offset mechanism coefficient of the negative offset mechanism be less than or equal to 0.1 can be eliminated by substantially increasing the force arm coefficient of the engine. Therefore, the inventive offset mechanism coefficient is set to 0.60 to 0.75.The results show that the effective thermal efficiency of the engine can be greatly improved by these offset mechanism coefficients.

[0014] The force arm coefficient of the negative offset double crankshaft connecting rod mechanism provided by the invention is ζ r,F . ζr,F=sin(α+sin−1((e+R×sin α) / L))cos(sin−1((e+R×sin α) / L))

[0015] The force arm coefficient of the negative offset reverse pull double crankshaft connecting rod mechanism provided by the invention is ζ r,FL . ζr,FL=sin(α−sin−1((e+R×sin α) / L))cos(sin−1((e+R×sin α) / L))

[0016] In formulas I and II, L is the crank connecting rod length, R is the crank radius, e is the eccentricity, β=sin−1(e+R×sin αL), α is the crankshaft rotation angle.

[0017] From formulas I and II, it can be seen that the force arm coefficient depends on the negative offset of the crankshaft and the direction of the force applied to the crank connecting rod. At the same time, it is positively correlated with the eccentricity e and is related to the crank connecting rod length L and the crank radius R. Therefore, the geometric properties of the double crankshaft connecting rod mechanism can be determined by adjusting the eccentricity e, the crank connecting rod length L, and the crank radius r. Therefore, σ pz expressed as displacement mechanism coefficient σ pz=e / (LR), that is, the offset mechanism coefficient is the quotient of the difference between the crank connecting rod length and the crank radius divided by the eccentricity e. Therefore, when the offset mechanism coefficient is set to 0.60 to 0.75, the transmission performance of the engine power transmission mechanism can be improved by increasing the negative offset force arm coefficient of the crankshaft. That is, the effective thermal efficiency of the engine is improved.

[0018] The power transmission mechanism for improving the effective thermal efficiency of the engine, provided by the method of the present invention, also has the advantages of significant power improvement, oil savings, and low exhaust emissions. It also exhibits high power and high torque. The power stroke is accelerated, which has a positive effect on improving the combustion and compression ratio and reducing heat loss. It has few parts and low production costs. The length of the connecting rod is reduced, making the entire mechanism compact.

[0019] When the crankshaft rotates with a negative offset, the lubricating oil sprayed from the crankshaft always points toward the piston. The piston-cylinder block is well lubricated. The engine oil has strong heat dissipation to the piston, and the engine has high durability and a long service life. Description of the characters Fig. 1 is a schematic diagram of the power transmission mechanism of the negative offset double crankshaft connecting rod. Fig. 2 is a schematic diagram of the power transmission mechanism of the negative offset reverse pull double crankshaft connecting rod according to the invention. Fig. 3 is a schematic diagram of the horizontally arranged power transmission mechanism of the negative offset reverse pull double crankshaft connecting rod according to the invention. Fig. 4 is the force arm coefficient curve of the crankshaft connecting rod when the offset mechanism coefficient is 0.75. Fig. 5 is the force arm coefficient curve of the crankshaft connecting rod when the offset mechanism coefficient is 0.95. Fig.6 is the ratio of the shaft working value of the crankshaft connecting rod in the working mode such as with negative offset reverse pull, in negative offset, in positive offset and without offset to the shaft working value of the working mode without offset when the offset mechanism coefficient is 0.91. Fig. Figure 7 is the PV diagram of the power transmission mechanism with positive and negative offset reverse pull of the motor when the offset mechanism coefficient is 0.91. Fig. Figure 8 is a schematic diagram of the power output mechanism of a two-stroke, negative offset, reverse pull, twin crankshaft connecting rod engine. Fig. 9 is the force arm coefficient curve of the crankshaft connecting rod when the offset mechanism coefficient is 0.60. Specific embodiments

[0020] The invention is further described with reference to the accompanying figures.

[0021] The present invention relates to a power transmission mechanism for improving the effective thermal efficiency of an engine, in which the eccentricity between the crankshaft axis and the connecting end axis of the piston rod and the crank connecting rod, or between the crankshaft axis and the pin shaft center on the piston and the connecting end axis of the crank connecting rod in the engine power transmission mechanism is set, wherein the eccentricity e is set larger than the crank radius R, wherein the two crankshafts are arranged in negative offset or negative offset reverse pull mode, wherein the offset mechanism coefficient is the quotient of the difference between the crank connecting rod length and the crank radius divided by the eccentricity e, wherein the offset mechanism coefficient is set to 0.60 to 0.75,wherein the engine power transmission mechanism is provided with the offset mechanism coefficient.,

[0022] The eccentricity described in the above method is applicable to the negative offset arrangement of the double crankshaft and the negative offset reverse pull arrangement of the double crankshaft.

[0023] If the negative offset arrangement of the double crankshaft is adopted, the connection between the piston and the crank connecting rod can be realized in several ways: (1) The piston is connected to the piston rod, the piston rod is connected to the two crank connecting rods, and the connecting end of the piston rod and the two crank connecting rods is above the center of the crankshaft. (2) A circular sliding block is installed on the piston, and two pin shafts are installed on the circular sliding block. Each pin shaft is connected to its own crank connecting rod. In this case, the eccentricity is the distance between the crankshaft axis and the connecting end axis of the pin shaft and the crank connecting rod on the circular sliding block. (3) The piston is directly connected to two crank connecting rods. In this case, the eccentricity is the distance between the crankshaft axis and the connecting end axis of the piston and the crank connecting rod.

[0024] The displacement mechanism coefficient is 0.6 to 0.75.

[0025] The method of the invention overcomes the long-standing prejudice of technical personnel in the field. According to the research of the invention, the transmission efficiency of the engine power transmission mechanism can be improved by increasing the maximum value of the force arm coefficient, that is, the effective thermal efficiency of the engine is improved by bringing it as close as possible to the crankshaft rotation angle generated by the maximum combustion pressure in the double crankshaft connecting rod power transmission mechanism. Table 1: Change table of the crankshaft rotation angle θmax according to the maximum value ζr,max of the force arm coefficient of the offset mechanism coefficient σpz and the crankshaft in different offset modes (λ = 1 / 3.5, λ means connecting rod ratio) s pz Arrangement of the double crankshaft with positive offset Arrangement of the double crankshaft with negative offset Arrangement of the double crankshaft with negative offset reverse pull g r,max i max g r,max i max g r,max i max 0,40 1,00 77,16 1,18 75,20 1,18 94,06 0,50 1,00 78,10 1,25 75,65 1,25 90,48 0,60 1,01 79,33 1,33 76,40 1,33 86,20 0,65 1,02 80,10 1,38 76,94 1,38 83,66 0,70 1,03 80,97 1,44 77,62 1,44 80,82 0,75 1,04 82,00 1,51 78,51 1,51 77,52 0,80 1,05 83,24 1,60 79,70 1,60 73,56 0,85 1,06 84,77 1,71 81,38 1,71 68,58 0,90 1,08 86,70 1,87 83,90 1,87 61,95 0,95 1,11 89,27 2,10 88,43 2,10 51,60

[0026] According to the data in the table above: (1) The force arm coefficient of the positive offset crankshaft changes only slightly when the offset mechanism coefficient changes from small to large: however, the corresponding crankshaft rotation angle is gradually away from the top dead center. (2) The force arm coefficient of the crankshaft with negative offset increases sharply, but the corresponding crankshaft rotation angle gradually moves away from the top dead center. When the offset mechanism coefficient increases from 0.4 to 0.4, the force arm coefficient increases smoothly, and the force arm coefficient increases rapidly when the offset mechanism coefficient increases from 0.6 to 0.8. (3) When the force arm coefficient of the negative offset-reverse pull crankshaft increases sharply, the crankshaft rotation angle gradually approaches the top dead center. When the maximum value of the offset mechanism force arm coefficient is 0.4, corresponding to a crankshaft rotation angle of 94.06 degrees, it deviates too far from the top dead center of the maximum air cylinder pressure. When the maximum value of the offset mechanism force arm coefficient is 0.60, corresponding to a crankshaft rotation angle of 86.20 degrees, the increase in the offset mechanism coefficient and the maximum value of the force arm coefficient corresponds to the change in the crankshaft rotation angle, and this change is also very ideal. Therefore, the negative offset-reverse pull crankshaft arrangement and the negative offset crankshaft arrangement are the preferred arrangements.

[0027] The preferred displacement mechanism coefficient of the invention is 0.6 to 0.75. When the displacement mechanism coefficient is 0.6 to 0.75, the effect is better than 0.4 to 0.59.

[0028] The relationship between the offset mechanism coefficient of the engine power transmission mechanism and the power changes greatly. Table 2 shows the output data of the performance experiment of three offset modes of a double crankshaft engine Unit: W s pz e (cm) R / L. S (cm) Output power of the double crankshaft with positive offset Output power of the double crankshaft with negative offset Dual crankshaft output with negative offset reverse pull 0,60 4,42 0,22 4,74 901 956 990 0,75 5,50 0,22 5,22 988 1068 1105 0,85 6,2 0,22 5,74 1080 1193 1225 0,90 6,6 0,22 6,19 1160 1298 1320 0,95 7 0,22 6,91 1290 1480 1469 Experimental test status: Full throttle, FAI injector 7.05 milliseconds, compression ratio 9, fixed rpm (2543-2596). A Wande T200 digital phase voltammeter is used.

[0029] In Table 2: σ pz - Offset mechanism coefficient, e-eccentricity, L-crank connecting rod length, R-crank radius, S-piston stroke.

[0030] It can be seen from Table 2 that when the offset mechanism coefficient is 0.6 to 0.95, the performance of the engine power output mechanism with negative offset arrangement and negative offset reverse pull arrangement is significantly higher than that of the prior art crankshaft power output mechanism with positive offset.

[0031] In Table 2: the crank connecting rod length L = 9.4 cm, the crank radius R = 2.07 cm, the eccentricity e = 4.42 cm, the offset mechanism coefficient σ pz = 0.6, and the force arm coefficient curve of the connecting rod is in Fig. 9. The experimental results show that the temperature of the cylinder head in the negative offset working condition is lower than that in the positive offset working condition, which proves that the heat loss is small and the thermal efficiency is improved when it is in the negative offset working condition.

[0032] The negative offset of the crankshaft of the invention refers to the working stroke of the engine power output mechanism, and the crank rotation angle range is less than 180 degrees, as in Fig. 1. If the crank angle range during the power stroke is greater than 180 degrees, this is referred to as a positive crankshaft offset.

[0033] The negative offset reverse pull of the crankshaft of the present invention refers to the fact that the crank rotation angle range of the engine's power output mechanism in the power stroke is less than 180 degrees, while the connecting rod bears the pulling force in the power stroke, that is, the connecting end of the piston rod and the connecting rod is on the opposite side of the installation direction of the pistons on the center lines of the two crankshafts. As shown in Fig.2, the connecting ends of the piston rod and the two crank connecting rod mechanisms are located below the centers of the two crankshafts.

[0034] In Table 2, with the increase of the offset mechanism coefficient, the piston stroke S increases, thereby increasing the engine displacement. The obtained power value cannot be compared by longitudinal analysis. The influence of increasing piston stroke on the power value must be eliminated proportionally. Take these data as criteria: the offset mechanism coefficient is 0.60, the piston stroke is 4.74 cm, and the traditional positive offset power value is 901 W. First, the piston stroke increase ratio of other offset mechanism coefficient values ​​is calculated, and then the product of the stroke increase ratio and the reference power value (901 W) is divided by the traditional values ​​of positive offset, negative offset, and negative offset reverse pull, and the quotient is the power correction ratio, that is, the output efficiency relative to the traditional positive reference offset. Table 3: Table of correction ratio of the performance experiment in Table 2 s pz S (cm) Lift increase ratio Positive offset Negative offset Negative offset reverse pull 0,60 4,74 1,000 1,000 1,061 1,099 0,75 5,22 1,101 0,996 1,076 1,114 0,85 5,74 1,211 0,990 1,093 1,123 0,90 6,19 1,306 0,986 1,103 1,122 0,95 6,91 1,458 0,982 1,127 1,118

[0035] According to the data in Table 3, the traditional positive offset column shows that the offset mechanism coefficient of the power transmission mechanism is negatively correlated with the output efficiency. The negative offset column shows that the offset mechanism coefficient of the power transmission mechanism is positively correlated with the output efficiency, and the output efficiency increases monotonically. The negative offset reverse pull column shows that the output efficiency of the power transmission mechanism increases by 10% when the offset mechanism coefficient is 0.6. When the offset mechanism coefficient is 0.85, the output efficiency reaches a high point. When the offset mechanism coefficient continues to increase to 0.95, the output efficiency remains at a high level and decreases slightly.

[0036] A power transmission mechanism for improving the effective thermal efficiency of the engine defined by the method of the invention is a double crankshaft connecting rod mechanism. As in Fig. 1 and Fig.As shown in Figure 2, the first crankshaft 6 and the third crankshaft 14 rotate clockwise, while the second crankshaft 7 and the fourth crankshaft 22 rotate counterclockwise. The eccentricity is set between the crankshaft axis and the connecting end axis of the piston rod and the crank connecting rod, or between the crankshaft axis and the pin shaft center on the piston and the connecting end axis of the crank connecting rod, where the eccentricity e is set larger than the crank radius R. The two crankshafts are arranged in a negative offset arrangement or a negative offset reverse pull arrangement. The housing and the air cylinder of the engine power transmission mechanism, as well as the connection relationship with other components and the installation position, are the same as those of the prior art.When the crankshaft connecting rod mechanism moves, the eccentricity is the distance between the crankshaft axis and the center of the pin shaft on the circular sliding block and the centerline of motion of the connecting shaft of the crank connecting rod. Eccentricity can also be the distance between the crankshaft axis and the centerline of motion of the connecting shaft of the piston and the crank connecting rod. Eccentricity can also be the distance between the crankshaft axis and the centerline of motion of the connecting shaft of the piston rod and the crank connecting rod. The connecting end of the piston rod and the crank connecting rod is above the centerline of the crankshaft.

[0037] The positions of each component in the invention are shown in the figure.

[0038] The engine power transmission mechanism applicable to the method according to the invention is shown in Fig. 1, Fig.2 and Fig. 3, but the present invention is not limited to these embodiments. Since the connection of the housing, the air cylinder, and other parts of the power transmission mechanism with the structure shown in the figure is a known technology, the Fig. 1, Fig. 2 and Fig. 3 the schematic diagram of the double crankshaft connecting rod mechanism.

[0039] Fig. 1 shows a connecting rod mechanism with a negative offset of the double crankshaft to improve the effective thermal efficiency of the engine. Fig.In the negative offset structure shown in Figure 1, the connection between the piston and the crank connecting rod is realized by the circular sliding block and its pin shaft on the circular sliding block, which is one of the preferred methods. The structure for connecting the piston and the crank connecting rod can also be: the piston is connected to one end of each of the two crank connecting rods, or the piston is connected to the piston rod. The other end of the piston rod is connected to two crank connecting rods, respectively. The connecting ends of the piston rod and the two crank connecting rods are located above the centers of two crankshafts.

[0040] In Fig.1 is the first air cylinder and 2 is the first piston. A circular sliding block 20 is installed on the first piston. The first pin shaft 26 and the second pin shaft 27 are installed on the circular sliding block 20. The first pin shaft 26 is connected to one end of the first crank connecting rod 4. The other end of the first crank connecting rod 4 is connected to one end of the first crank 5 via the first crank journal 9. The other end of the first crank 5 is connected to the first crankshaft 6. The first crankshaft 6 is fixedly connected to the first synchronous gear 8. The distance between the axis of the first crankshaft 6, the axis of the first pin shaft 26, and the connecting end axis of the first crank connecting rod 4 is the first eccentricity e1. The first eccentricity e1 is larger than the radius R of the first crank 5. The second pin shaft 27 is connected to one end of the second crank connecting rod 28.The other end of the second crank connecting rod 28 is connected to one end of the second crank 29 via the second crankshaft 30. The other end of the second crank 29 is connected to the second crankshaft 7. The second crankshaft 7 is fixedly connected to the second synchronous gear 25. The first synchronous gear 8 is engaged with the second synchronous gear 25. The first crankshaft 6 rotates clockwise. The second crankshaft 7 rotates counterclockwise through a synchronous gear fixedly connected to them. The crankshaft connecting rod mechanism of the second crankshaft 7 moves symmetrically with the crankshaft connecting rod mechanism of the first crankshaft 6 with the moving center line of the first piston 2 as a plane. The rotation angle range of the crank in the power stroke is less than 180 degrees. The vertical position f of the first crank 5 is 0 degrees from the starting point.The included angle between the first crank 5 and the starting point is a. The included angle between the first crank connecting rod 4 and the axis of the first pin shaft on the piston is β.

[0041] Fig.Figure 2 shows the crankshaft connecting rod mechanism of the double crankshaft with a negative offset reverse pull arrangement for improving the effective thermal efficiency of the engine. In the figures, 10 is the second air cylinder. A second piston 11 is installed in the second air cylinder 10. The second piston 11 is connected to one end of the piston rod 12. The other end of the piston rod 12 is connected to one end of the third crank connecting rod 17 and one end of the fourth crank connecting rod 18, respectively. The other end of the third crank connecting rod 17 is connected to one end of the third crank 15 via the third crankshaft journal 16. The other end of the third crank 15 is connected to the third crankshaft 14. The other end of the fourth crank connecting rod 18 is connected to one end of the fourth crank 19 via the fourth crankshaft journal 21.The other end of the fourth crank 19 is connected to the fourth crankshaft 22. The third crankshaft 14 is synchronously and fixedly connected to the third gear 13. The fourth crankshaft 22 is synchronously and fixedly connected to the fourth gear 23. The third crankshaft 14 rotates clockwise. The fourth crankshaft 22 rotates counterclockwise. The third gear 13 meshes with the fourth gear 23. The vertical position f of the third crank 15 is 0 degrees from the starting point. The included angle between the third crank 15 and the starting point is α. The included angle between the third connecting rod 17 and the straight line of piston movement is β. The distance between the axis of the third crankshaft 14 and the connecting end axis of the third connecting rod 17 and the piston rod 12 is the second eccentricity e2. The second eccentricity e2 is larger than the radius of the third crank 15.The crankshaft connecting rod mechanism of the fourth crankshaft 22 moves symmetrically with the crankshaft connecting rod mechanism of the third crankshaft 14 with the piston movement centerline as a plane.

[0042] Fig. 3 shows a solution for two horizontally opposed reverse pull structures with negative offset, which are Fig. 2. To reduce the volume, the directly coupled synchronous third gear 13 and the fourth gear 23 are changed into two meshing intermediate gears. After deceleration, the intermediate gear meshes with the center gear 24, and the power is output via the central output shaft 31. In the Fig. 3, the crank connecting rod length L is 4.7 cm, the crank radius R is 1.3 cm, the eccentricity e is 3.1 cm and the offset mechanism coefficient σ pz= 0.91. The experimental output power is 1.23 times the output power without offset (at the same fuel consumption and displacement).

[0043] A power transmission mechanism manufactured according to a method for improving the effective thermal efficiency of the engine, comprising a housing, wherein an air cylinder is installed in the housing, wherein a piston is installed in the air cylinder, wherein one end of the piston rod is connected to the piston, wherein the other end of the piston rod is each connected to two crank connecting rod mechanisms, wherein the two crank connecting rod mechanisms have the same structure and are arranged symmetrically on both sides of the air cylinder, wherein the eccentricity e between the crankshaft axis and the connecting end axis of the piston rod and the crank connecting rod is greater than the crank radius R, wherein center lines of the two crankshafts are each perpendicular to the air cylinder center lines, wherein the two connecting ends of the piston rod for connecting two crank connecting rod mechanisms are located below the crankshaft.

[0044] The two crankshafts are the first crankshaft 6 and the second crankshaft 7, with the first crankshaft 6 rotating clockwise and the second crankshaft 7 rotating counterclockwise.

[0045] The quotient of the difference between the crank connecting rod length L and the crank radius R, divided by the eccentricity e, is 0.6-0.75.

[0046] The effects in the above solution are described in Tables 1, 2 and 3 of the present invention and by the Fig. 4-7. The displacement mechanism coefficient σ shown in the table and in the figure pz is the quotient of the difference between the crank connecting rod length L and the crank radius R, divided by the eccentricity e.

[0047] The structure, shape and positional relationship of the housing, the air cylinder, the piston, the connecting rod, the crank and the crankshaft of the engine power transmission mechanism according to the invention are the same as those of the known technology.

[0048] When manufacturing the engine power transmission mechanism according to the invention, the offset mechanism coefficient is the quotient of the difference between the crank connecting rod length L and the crank radius R divided by the eccentricity e. The prerequisite for setting the offset mechanism coefficient is that the eccentricity is greater than the crank radius. The offset mechanism coefficient is 0.6 to 0.75. All of the above offset mechanism coefficients can increase the performance of the engine's dual crankshaft connecting rod power output mechanism. Each value within the offset mechanism coefficient range can improve the performance of the engine power transmission mechanism. For example, the offset mechanism coefficient is 0.6, 0.62, 0.65, 0.68, 0.70, 0.73, or 0.75. When the offset mechanism coefficient σ pzis set to 0.98, e is 7.2 cm, R / L is 0.22, S is 7.55 cm, the power of the engine power transmission mechanism with negative offset arrangement of the double crankshaft is 1505, the power of the engine power transmission mechanism with negative offset reverse pull arrangement of the double crankshaft is 1430, and the power of the engine power transmission mechanism with positive offset arrangement of the prior art is 1282. The experimental conditions are the same as in Table 2, and the principle of the correction ratio is the same as in Table 3. The stroke change is 1.593, the negative offset output power is 1.174, and the negative offset reverse pull output power is 1.115.

[0049] The embodiments of the engine power transmission mechanism according to the invention are as follows: Embodiment 1: It has a first air cylinder 1. The first piston 2 is installed in the first air cylinder 1. A circular sliding block 20 is installed on the first piston. The first pin shaft 26 and the second pin shaft 27 are installed on the circular sliding block 20. The first pin shaft 26 is connected to one end of the first crank connecting rod 4. The other end of the first crank connecting rod 4 is connected to one end of the first crank 5 via the first crank journal 9. The other end of the first crank 5 is connected to the first crankshaft 6. The first crankshaft 6 is fixedly connected to the first synchronous gear 8. The distance between the axis of the first crankshaft 6 and the connecting end axis of the first pin shaft 26 and the first crank connecting rod 4 is the first eccentricity e1. The second pin shaft 27 is connected to one end of the second crank connecting rod 28.The other end of the second crank connecting rod 28 is connected to one end of the second crank 29 via the second crankshaft 30. The other end of the second crank 29 is connected to the second crankshaft 7. The second crankshaft 7 is fixedly connected to the second synchronous gear 25. The first gear 8 meshes with the second gear 25. The first eccentricity e1 is larger than the radius R of the first crank 5. The first crankshaft 6 rotates clockwise. The second crankshaft 7 rotates counterclockwise through a synchronous gear fixedly connected to them. The crankshaft connecting rod mechanism of the second crankshaft 7 moves symmetrically with the crankshaft connecting rod mechanism of the first crankshaft 6 with the moving center line of the first piston 2 as a plane. The rotation angle range of the crank in the power stroke is less than 180 degrees. The vertical position f of the first crank 5 is 0 degrees from the starting point.The included angle between the first crank 5 and the starting point is a. The included angle between the first crank connecting rod 4 and the straight line of piston motion is β. Embodiment 2: It has a second air cylinder 10. A second piston 11 is installed in the second air cylinder 10. The second piston 11 is connected to one end of the piston rod 12. The other end of the piston rod 12 is connected to one end of the third crank connecting rod 17 and one end of the fourth crank connecting rod 18, respectively. The other end of the third crank connecting rod 17 is connected to one end of the third crank 15 via the third crankshaft journal 16. The other end of the third crank 15 is connected to the third crankshaft 14. The other end of the fourth crank connecting rod 18 is connected to one end of the fourth crank 19 via the fourth crankshaft journal 21. The other end of the fourth crank 19 is connected to the fourth crankshaft 22. The third crankshaft 14 is synchronously and fixedly connected to the third gear 13. The fourth crankshaft 22 is synchronously and fixedly connected to the fourth gear 23.The third crankshaft 14 rotates clockwise. The fourth crankshaft 22 rotates counterclockwise. The third gear 13 meshes with the fourth gear 23. The vertical position f of the third crank 15 is 0 degrees from the starting point. The included angle between the third crank 15 and the starting point is α. The included angle between the third connecting rod 17 and the straight piston movement line is β. The distance between the axis of the third crankshaft 14 and the connecting end axis of the third connecting rod 17 and the piston rod 12 is the second eccentricity e2. The second eccentricity e2 is larger than the radius of the third crank 15. The crankshaft connecting rod mechanism of the fourth crankshaft 22 moves symmetrically with the crankshaft connecting rod mechanism of the third crankshaft 14 with the piston movement centerline as the plane. Embodiment 3. As shown in Figure 3, the structure is a horizontally opposite solution to the reverse traction structure with negative offset described in both embodiments. To reduce volume, the directly coupled synchronous third gear 13 and the fourth gear 23 are changed into two meshing intermediate gears. After deceleration, the intermediate gear meshes with the center gear 24, and power is output via the central output shaft 31. Embodiment 4: As in Fig.As shown in Figure 8, it includes a piston slidably installed in the cylinder block and a scavenging piston. The upper part of the cylinder block is provided with an air outlet and a scavenging port, the lower part is provided with an air inlet, and the middle part is provided with a scavenging passage. An air inlet check valve is installed in the air inlet. Two meshing synchronous gears and opposing rotating crankshaft I and crankshaft II are installed at the lower end of the cylinder block. Crankshaft I and crankshaft II are respectively fixedly connected to the crank and crankshaft journal. The large end of the connecting rod, which can rotate around the shaft, and the large end of the connecting rod for scavenging are installed on the crankshaft journal. The piston is connected to the upper end of the piston rod. The piston rod passes through the center of the scavenging piston.The two ears at the bottom of the piston rod are respectively connected to the small end of the connecting rod installed on crankshaft I and crankshaft II. The two ears at the bottom of the scavenging piston are respectively connected to the small ends of the scavenging connecting rod by pins installed on crankshaft I and crankshaft II. Due to the sliding seal between the piston, scavenging piston and cylinder block, as well as the sliding seal between the middle part of the piston rod and scavenging piston, when the engine is running, the double crankshaft connecting rod works in the negative offset direction, that is, crankshaft I rotates clockwise and crankshaft II rotates counterclockwise. The connecting rod drives the reciprocating movement of the piston, and the scavenging connecting rod drives the reciprocating movement of the scavenging piston.As the piston moves upward, the scavenging volume, composed of the lower part and the upper part of the scavenging piston, increases, resulting in negative pressure. The combustible gas enters from the air inlet through the air inlet check valve, and the combustible gas in the upper cylinder block of the piston is compressed. The piston continues to travel to top dead center, and the gas in the air cylinder ignites to do work. As the piston moves downward, the scavenging volume becomes smaller. Since the air inlet check valve is closed at this time, the scavenging port is closed by the piston, and the combustible gas is compressed. As the piston continues to move downward, the air outlet and the scavenging port are opened sequentially. The compressed combustible gas is scavenged through the scavenging port. The crankshaft rotates for one cycle to complete the working cycle of the two-stroke engine.

[0050] In the Fig.4, the piston stroke of the conventional crankshaft without offset is 2R. The piston stroke Se increases after the crankshaft offset, and the force arm coefficients of the two should be converted according to the increasing proportion. The force arm coefficient of the crankshaft offset is given in ζr2Rse converted. If σ pz = 0.75, the general ratio for connecting rod length / crank radius λ=13.5 The force arm coefficient curve of the connecting rod mechanism of the twin crankshafts with negative offset-reverse pull (referred to as negative offset-reverse pull in the figure) and the force arm coefficient curve of the connecting rod mechanism of the twin crankshafts with negative offset (referred to as negative offset in the figure) are compared with the force arm coefficient curve of a conventional connecting rod mechanism of the single crankshafts without offset. The maximum value of the force arm coefficient curve is higher than 0.18, and the crankshaft rotation angle at top dead center is a maximum of 78° when reaching the maximum value. At this time, the force arm coefficient curves of the negative offset-reverse pull and the negative offset almost coincide, and σ pz = 0.75 is the critical point where the force arm coefficient curves of negative offset reverse pull and negative offset are similar.

[0051] In the Fig. 5, the piston stroke of the conventional crankshaft without offset is 2R. The piston stroke Se increases after the crankshaft offset, and the force arm coefficients of the two should be converted according to the increasing proportion. The force arm coefficient of the crankshaft offset is given in ζr2Rse converted. If σ pz = 0.95, the general ratio for connecting rod length / crank radius λ=13.5 The force arm coefficient curve of the connecting rod mechanism of the double crankshafts with negative offset reverse pull (in the Fig. 5 as negative offset reverse pull) and the force arm coefficient curve of the connecting rod mechanism of the double crankshafts with negative offset (in the Fig.5 referred to as negative offset) are compared with the force arm coefficient curve of a conventional connecting rod mechanism of the single crankshafts without offset (in Fig. 5 as without offset), the maximum value of the force arm coefficient curve is 0.29 higher. Specifically, at this time, when the maximum value of the force arm coefficient curve of the negative offset reverse pull is reached, the crankshaft rotation angle moves forward from the top dead center to 51°. Fig. 4 and Fig. 5, the piston stroke of the conventional crankshaft without offset is 2R. The piston stroke Se increases after the crankshaft offset, and the force arm coefficients of the two should be converted according to the increasing proportion.

[0052] The ratio of the Fig.6 shown shaft work value (the part of reducing friction and improving the mechanical efficiency of the double crankshaft connecting rod mechanism is not included) due to the difference in the maximum value of the force arm coefficient of the negative offset-reverse pull, negative offset, and positive offset, and due to the difference in the angle of the crankshaft caused by the maximum value of the force arm coefficient of the negative offset-reverse pull, negative offset, the shaft work of the working mode with positive offset, negative offset, and negative offset-reverse pull is again greatly increased. When σ pz =0.91, the shaft work of the working mode with negative offset reverse pull is about 1.16 times that of the working mode without offset.

[0053] The Fig.The PV diagram shown in Figure 7 is based on the traditional theory of the internal combustion engine. According to engineering thermodynamics, the cycle work of the piston is as follows: W0 = ∫ P g dv. The cyclically displayed performance diagram (PV diagram) of the piston expansion and the gas pressure P g during engine operation is shown. From the figure, it can be seen that the engine's reverse pull in the negative offset mode is significantly higher than the positive offset mode.

Claims

[1] A power transmission mechanism for improving an effective thermal efficiency of an engine, the power transmission mechanism comprising: - a first crankshaft (14) with a first crankshaft axis and a first crank (15), - a second crankshaft (22) with a second crankshaft axis and a second crank (19), - a first crank connecting rod (17) which is articulated with a first end to an end of the first crank (15) remote from the crankshaft axis, whereby a pivot axis is defined between the first crank (15) and the first crank connecting rod (17), - a second crank connecting rod (18) which is articulated with a first end to an end of the second crank (19) remote from the crankshaft axis, whereby a pivot axis is defined between the second crank (19) and the second crank connecting rod (18), - a connecting end axis to whose first end a second end of the first crank connecting rod (17) is articulated, whereby a pivot axis is defined between the connecting end axis and the first crank connecting rod (17), wherein a second end of the second crank connecting rod (18) is articulated at a second end of the connecting end axis, whereby a pivot axis is defined between the connecting end axis and the second crank connecting rod (18), - a piston rod (12) having a first end which is fixed to the connecting end axis centrally between its two pivot axes, characterized by , that a displacement mechanism coefficient σ pz is between 0.60 and 0.75, where the displacement mechanism coefficient σ pz is equal to the quotient of an eccentricity e divided by the difference of distances L and R, where L, R and e denote: - L is a distance between the two pivot axes of the first crank connecting rod (17), wherein a distance between the two pivot axes of the second crank connecting rod (18) is equal; - R is a distance between the first crankshaft axis and the pivot axis between the first crank (15) and the first crank connecting rod (17), wherein a distance between the second crankshaft axis and the pivot axis between the second crank (19) and the second crank connecting rod (18) is equal to R; - the eccentricity e is a distance equal to half the difference between the distances La and Lv, where La is a distance between the two crankshaft axes and Lv is a distance between the two pivot axes of the connecting end axis. [2] Power transmission mechanism according to claim 1, characterized byin that it comprises a housing, an air cylinder (10) being installed in the housing, a piston (11) being installed in the air cylinder (10), a second end of the piston rod (12) being connected to the piston (11), the two ends of the connecting end axis being each connected to a crank connecting rod mechanism, the two crank connecting rod mechanisms having the same structure and being arranged symmetrically on both sides of the air cylinder (10), the eccentricity e being greater than the crank radius R, the crankshaft axes each being perpendicular to an air cylinder center line, an imaginary connecting line between the two crankshaft axes being located between the connecting end axis and the second end of the piston rod (12). [3] Power transmission mechanism according to claim 2, characterized bythat the first crankshaft (14) rotates clockwise and the second crankshaft (22) rotates counterclockwise.

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