JP2007239729A - Double connecting rod crank mechanism of reciprocating engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To vary an intake stroke, while securing the predetermined compression ratio, by increasing the expansion ratio to the compression ratio, in a crank mechanism of a four-cycle reciprocating engine. <P>SOLUTION: This crank mechanism is formed on the basis of a double connecting rod crank mechanism composed of a main connecting rod 2, a sub-connecting rod 7 and a crank arm 10. A stroke of an expansion-exhaust stroke is set to two times the length of a crank 10, and a stroke of an intake-compression stroke is set shorter than the stroke of the expansion-exhaust stroke in two times the length of the sub-connecting rod 7. A gear (A) 17 is rotatably arranged around a crankshaft 11, and the sub-connecting rod 7 is connected to a gear (B) 18. A gear (C) 20 is arranged so as to mesh with the gears (A) 17 and (B) 18. Rotation of the gear (A) 17 is controlled by an intake stroke setting device 35 and a compression ratio setting device 45 arranged on the engine body side. The intake stroke is varied by rotating the sub-connecting rod 7 in the intake stroke and the compression stroke, and the predetermined compression ratio is secured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

Detailed Description of the Invention

The present invention relates to a crank mechanism that increases an expansion / exhaust stroke stroke with respect to an intake / compression stroke stroke, a variable intake mechanism that changes an intake stroke (intake amount) within a certain range, and an intake amount in a four-cycle reciprocating engine. A variable compression mechanism that secures a predetermined compression ratio according to the change in the pressure and changes the compression ratio from the spark ignition region to the compression ignition region, a vibration-proof mechanism that prevents vibrations generated by the rotation of the sub-connecting rod of the above mechanism, Etc.

The intake / exhaust of a 4-cycle reciprocating engine is controlled by opening / closing the intake valve / exhaust valve. It takes a certain amount of time from the start of opening / closing until it is fully opened or fully closed. From the viewpoint of minimization and maximization of the intake air amount, it closes after bottom dead center, and the crankshaft rotation angle is 20 to 60 degrees later. The piston after the bottom dead center starts to rise and pushes back the intake air before the start of compression to the intake port side, and the actual intake air amount is smaller than the intake stroke volume.

The timing at which the exhaust valve starts to open is determined based on the balance between the work of the expansion pressure at the end of the expansion stroke and the amount of exhaust load loss at the beginning of the exhaust stroke. 30 to 80 degrees ago. Accordingly, exhaust starts while leaving an unconverted pressure that cannot convert the expansion pressure in the expansion stroke into rotation, and the substantial expansion stroke stroke is reduced, which contributes to a reduction in efficiency.

Therefore, the intake volume is reduced by setting the timing of closing the intake valve to an early timing (early closing method) before the piston bottom dead center or a late timing (late closing method), and a substantial intake / compression stroke stroke. Is shortened to ensure a predetermined actual compression ratio, and by creating a relationship of “actual compression ratio <actual expansion ratio”, a so-called Miller cycle engine is realized to improve efficiency.

In addition, using a complicated link mechanism, the piston stroke of the four strokes of intake, compression, expansion, and exhaust is such that “compression stroke <suction stroke <expansion stroke <exhaust stroke” and “compression ratio <expansion ratio” relationship Atkinson engine that realizes is known.

Further, Japanese Patent Application Laid-Open No. 10-259735 discloses a crank mechanism including a main connecting rod, a sub connecting rod, and a crank arm, and a connecting portion of the main connecting rod and the sub connecting rod is controlled by the sub crank mechanism, whereby a suction / compression stroke is performed. In contrast, a reciprocating engine crank mechanism is disclosed in which the piston stroke in the expansion / exhaust stroke is increased.

In Japanese Patent Laid-Open No. 2001-50067, a connecting rod is rotatably connected to a sliding member inserted in a piston by a piston pin, and a sliding range of the sliding member is defined, whereby a suction / compression process is performed. In contrast, a reciprocating engine crank mechanism is disclosed in which the piston stroke in the expansion / exhaust stroke is increased.

However, by controlling the closing timing of the conventional intake valve, the reduction of the unconverted residual pressure that cannot convert the expansion pressure into rotation is realized by reducing the substantial suction stroke, but the unconverted pressure still remains. Has been. However, the current situation is the limit because increasing the pumping loss in the intake stroke and reducing the actual effect to further reduce it.

Atkinson's engine has a large mechanical loss due to a very complicated link mechanism, and it is not easy to deal with vibrations against a complicated link motion.

The crank mechanism described in Japanese Patent Laid-Open No. 10-259735 has a problem that the sub-connecting rod has a complicated motion due to the double crank mechanism, but the conventional balancing weight method cannot realize sufficient vibration isolation. The crank mechanism described in Japanese Patent No. 50067 has a problem that the minimum piston diameter is limited because the piston pin needs to be slid inside the limited piston.

The present invention is a double connecting rod crank mechanism for changing the effective length of the connecting rod in the intake / compression stroke to solve the above-mentioned problems, and the stroke of the intake / compression stroke is expanded by changing the effective length of the connecting rod.・ The intake stroke is made variable by changing the effective length of the connecting rod at the end of the intake stroke (bottom dead center), making it smaller than the stroke of the exhaust stroke, and the connecting rod at the end of the compression stroke (top dead center). By changing the effective length, the compression stroke can be varied to ensure a predetermined compression ratio according to the intake stroke, and the vibration generated by these mechanisms is synchronized with the movement of the connecting rod and the anti-vibration balancing weight is rotated. It achieves dynamic image stabilization.

The stroke of the intake / compression stroke can be shorter than the stroke of the expansion / exhaust stroke, and a mirror cycle engine with a larger expansion ratio than the compression ratio can be realized to minimize unconverted expansion force to rotational force. .

In addition, the crank arm length of the expansion / exhaust stroke can be increased to an optimum expansion ratio without being restricted by the intake / compression stroke, and an engine with high torque performance can be obtained. . Further, since the intake / compression start delay occurs, optimization of the opening / closing timing of the intake / exhaust valve that minimizes intake loss / exhaust residual gas can be easily realized.

By controlling the rotation of the auxiliary connecting rod by the end of the intake stroke, the intake stroke is changed within a range where the maximum intake stroke is twice the crank length and the minimum stroke is shorter than the maximum stroke by twice the auxiliary connecting rod length. , You can select the optimal intake capacity that matches the driving conditions, detect the amount of accelerator depression and depression acceleration, increase the intake stroke when there is no change in the depression amount and the engine speed decreases and when the depression exceeds the reference acceleration, Similarly, a torque control engine that adjusts the engine capacity, such as reducing the intake stroke when the rotational speed increases, can be realized.

Also, the compression stroke can be changed according to the intake stroke to ensure a predetermined compression ratio, and the compression ratio can be changed from the spark ignition region to the compression ignition region, whether it is a gasoline engine or a diesel engine. It is possible to realize a multi-function engine that can be used properly.

The natural vibration of the crank mechanism can be prevented by the conventional anti-vibration balancing weight method, but the conventional vibration-proof method cannot prevent vibration caused by the rotation of the secondary connecting rod. Anti-vibration can be achieved by the anti-vibration balancing weight method that rotates symmetrically with the movement of the connecting rod.

A first embodiment of the present invention will be described in detail based on the drawings.
FIG. 1A is a configuration diagram of a crank mechanism state at the bottom dead center of the intake stroke of the four-cycle reciprocating engine according to the first embodiment and a length increasing mechanism of the connecting rod at the bottom dead center.
FIG.1 (b) is AA sectional drawing of a lengthening mechanism.
In FIG. 1A, a main connecting rod 2 is rotatably connected by a piston pin 3 to a piston 1 slidably fitted in a cylinder (not shown) and connected to the other end of the main connecting rod 2. The cylinder 4 is mounted and fixed, the connecting piston 6 mounted and fixed to the sub connecting rod 7 is slidably fitted to the connecting cylinder 4, the end stopper 5 is mounted and fixed to the connecting cylinder 4, and the sliding length KL is defined. The other end of the sub connecting rod 7 is pivotally connected to the crank arm 10 by a crank pin 9 to constitute a crank mechanism that can increase the length of the connecting rod 2 by KL at the bottom dead center.

Next, the operation of the crank mechanism configured as described above will be described.
FIG. 1 shows the state of the crank mechanism at the bottom dead center of the intake stroke. When the compression stroke advances from this state and reaches the top dead center, the connecting piston 6 is pushed up by the compression load and the specified sliding length KL = 0. It becomes. Similarly, the specified sliding length KL = 0 at the bottom dead center in the expansion stroke and the top dead center in the exhaust stroke. When the intake stroke proceeds from this state, the connecting cylinder 4 is pulled up by the specified sliding length KL by the intake load, and intake is started from this point, reaching the bottom dead center, and the intake is completed. When the compression stroke proceeds from this state, the connecting piston 6 is pushed up by the specified sliding length KL by the compression load, compression starts from this point, reaches top dead center, and the compression is completed.
The intake / compression stroke S1 is determined by Equation 1, the expansion / exhaust stroke S2 is determined by Equation 2, and the difference RK (= S2−S1) between the intake / compression stroke S1 and the expansion / exhaust stroke stroke S2 is defined as sliding. Length KL.
Therefore, the stroke of the intake / compression stroke can be set smaller than the stroke of the expansion / exhaust stroke, and a mirror cycle engine having an expansion ratio larger than the compression ratio can be realized.

In the intake stroke, the rotation angle section of the crankshaft that acts to raise the connecting cylinder 4 by the specified sliding length KL is an intake start delay θ1 at which no intake action is performed, and is determined by Equation 3. In the compression stroke, the rotation angle section of the crankshaft that acts to push up the connecting piston 6 by the specified sliding length KL is the compression start delay θ2 and is determined by Equation 4.

Table 1 shows an example of the mechanism of the first embodiment, and FIG. 4 shows a displacement diagram of the piston stroke. The intake start delay θ1 and the compression start delay θ2 vary depending on the total length of the connecting rod (= L2 + L3). If the length is shortened, θ1 becomes smaller, and if the length is lengthened, θ2 becomes smaller. The angle can be set.

A second embodiment of the present invention will be described.
FIG. 2 schematically shows the configuration of a double connecting rod crank mechanism of a four-cycle reciprocating engine according to the second embodiment. As shown in FIG. 2, a main connecting rod 2 is rotatably connected to a piston 1 slidably fitted in a cylinder (not shown) by a piston pin 3, and the other end of the main connecting rod 2 is connected to a sub-portion. The connecting rod 7 is rotatably connected by a connecting rod pin 8, the other end of the sub connecting rod 7 is rotatably connected to the crank arm 10 by a crank pin 9, and the other end of the crank arm 10 is fixed to the crankshaft 11. Connected to form a double connecting rod crank mechanism.

Next, the operation of the second embodiment configured as described above will be described.
FIG. 2A shows the state of the piston top dead center TDC, but the piston top dead center TDC in the compression stroke and the exhaust stroke is constant. FIGS. 2B and 2C show the state of the piston bottom dead center BDC. The piston bottom dead center BDC2 in the expansion stroke is located below the piston bottom dead center BDC1 in the intake stroke. Therefore, the expansion stroke and the exhaust stroke S2 are increased by the stroke difference RK with respect to the intake stroke and the compression stroke S1, and the expansion ratio can be made larger than the compression ratio, and a mirror cycle engine can be realized.

Next, the mechanism action for generating the stroke difference RK will be described with reference to FIG.
Although the rotation direction of the crankshaft is indicated by an arrow in FIG. 3 in the clockwise direction, the rotation direction is not limited, but the following description will be expanded as a clockwise direction.
Regarding the rotation direction, the clockwise direction is indicated as “+ rotation”, and the counterclockwise direction is indicated as “−rotation”, and the following description will be expanded.

As shown in FIG. 3, the connecting rod pin 8 at the piston top dead center TDC is located below the crankpin 9. This is because the connecting rod pin 8 is pushed down toward the center of the crankshaft by the compression load in the immediately preceding compression stroke or the exhaust load in the exhaust stroke.

In FIG. 3 (a), when the crankshaft 11 rotates + and the intake stroke starts and the crankpin 9 rotates to the point P1, the secondary connecting rod is set so that the piston 1 is restrained or minimized from the top dead center TDC. 7 rotates + around the crankpin 9. Further, while the crankshaft 11 is rotated and the crankshaft 11 is rotated to the point P2 where the main connecting rod 2 and the sub connecting rod 7 are aligned, the piston 1 is similarly suppressed or minimized from descending from the top dead center. Thus, the secondary connecting rod 7 rotates + about the crankpin 9. Accordingly, if the crankshaft rotation angle up to point P2 of the crankpin 9 is θ1, substantial intake is not performed in the interval θ1, and θ1 corresponds to an intake delay.

When the rotation further exceeds the crankshaft rotation angle θ1, the piston 1 starts to descend from the top dead center TDC while the main connecting rod 2 and the sub connecting rod 7 are kept in a straight line, and the intake starts and the bottom dead center BDC of the intake stroke is started. Then, the connecting rod pin 8 is positioned above the crankpin 9 as shown in FIG.

Therefore, if the length between the crankshaft 11 center P11 and the crankpin 9 center P9 is the crank arm length L1, and the length between the connecting rod pin 8 center P8 and the crankpin 9 center P9 is the sub connecting rod length L2, the intake air The stroke S1 is determined by Equation 5.

In FIG. 3A, when the crankshaft 11 rotates + and the compression stroke starts and the crankpin 9 rotates to the point P3, the secondary connecting rod is controlled so that the piston 1 is restrained or minimized from the bottom dead center BDC1. 7 rotates + around the crankpin 9. Further, while the crankshaft 11 is rotated and the crankshaft 11 is rotated to the point P4 where the main connecting rod 2 and the sub connecting rod 7 are aligned, the piston is similarly prevented or minimized from rising from the bottom dead center. The sub connecting rod 7 rotates + around the crankpin 9. Therefore, if the crankshaft rotation angle up to point P4 of the crankpin 9 is θ2, the section θ2 does not act as a substantial compression stroke, and θ2 corresponds to a compression delay.

When the rotation further exceeds the crankshaft rotation angle θ2, the piston 1 starts to rise from the bottom dead center BDC1 while the main connecting rod 2 and the sub connecting rod 7 are kept in a straight line, and the compression starts, and the top dead center TDC of the compression stroke is started. Then, as shown in FIG. 2A, the connecting rod pin 8 is located below the crank pin 9.
Therefore, the compression stroke S1 is determined by Equation 5 as with the intake stroke.

In FIG. 3 (b), when the expansion stroke starts and the crankshaft 11 rotates, the sub connecting rod 7 rotates about the crank pin 9 so that the main connecting rod 2 and the sub connecting rod 7 are aligned. While rotating, it reaches the bottom dead center BDC2, and the connecting rod pin 8 is positioned below the crankpin 9 as shown in FIG.
Further, when the crankshaft 11 rotates and the exhaust stroke starts, the sub connecting rod 7 rotates + about the crank pin 9 so that the main connecting rod 2 and the sub connecting rod 7 are aligned. The point TDC is reached, and the connecting rod pin 8 is positioned below the crankpin 9 as shown in FIG.
Therefore, S2 of the expansion stroke and the exhaust stroke is determined by Equation 2.

That is, the stroke difference RK between the intake stroke and compression stroke S1 and the expansion stroke and exhaust stroke S2 is determined by Equation 6.

Accordingly, by changing the combination of the length L1 of the crank arm and the length L2 of the auxiliary connecting rod, the expansion stroke and the exhaust stroke S2 having the optimum stroke increase RK with respect to the required intake stroke and compression stroke S1 are set. And a mirror cycle having an expansion ratio larger than the compression ratio can be realized.

The intake start delay θ1 and the compression start delay θ2 shown in FIG. 3A vary depending on the combination of the crank arm length L1, the sub connecting rod length L2, and the main connecting rod length L3. Can be calculated.

Table 1 shows an example of the mechanism of the second embodiment.
In the original example, the crank arm length L1 and the auxiliary connecting rod length L2 are set so that the required compression stroke is St1 and the optimum expansion straw is St2, and the main connecting rod length L3 is the cylinder in the intake / compression stroke. The length is set such that the minimum gap between the inner wall and the main connecting rod can be secured. The intake start delay θ1 and the compression start delay θ2 at that time are calculated from Equations 9 and 10, and are tabulated.

As shown in the example of Table 1, the intake start delay θ1 is 34 to 46 degrees as the crankshaft rotation angle. At the start of intake, the exhaust valve finishes closing. During this time, the opening of the intake valve can be increased, and the intake load can be minimized and the mixture loss can be reduced.

The compression start delay θ2 is 44 to 65 degrees in terms of the crankshaft rotation angle.
At the start of compression, the intake valve can be closed and the actual intake amount can be made the intake stroke volume without intake loss.

FIG. 4 shows a displacement diagram of the piston in the intake / compression / expansion / exhaust stroke.
Although there is an advantage that the intake start delay θ1 and the compression start delay θ2 are generated, the intake / compression period is shortened and the intake / compression is rapidly performed. Therefore, it is preferable to optimize so that θ1 · θ2 does not become larger than necessary.

FIG. 5 shows an intake start angle setting mechanism. As shown in FIG. 5 (c), a rotation stop arm 13 is added to the crank arm 10, and a stop latch 14 for stopping the rotation of the sub connecting rod 7 is freely mounted on the arm. 7 is prevented from rotating by more than θK degrees with respect to the crank arm 10 and intake is started from the time when the crankshaft 11 is rotated by θ1X degrees from FIG. 5B showing the state at the top dead center.
Similarly, for the start of compression, a schematic diagram of the state where the crankshaft 11 is rotated by θ2Y degrees from the bottom dead center is shown in FIG. 6B, but the sub connecting rod 7 is prevented from rotating + θK degrees or more with respect to the crank arm 10. The compression is started from the time when the crankshaft 11 rotates by θ2Y degrees.

These start times are determined by the setting of the + rotation inhibition angle θK of the sub connecting rod 7.
A method for setting θK will be described with reference to FIG. 6A showing a schematic diagram at the start of intake and FIG. 6B showing a schematic diagram at the start of compression. If the optimal intake start angle is θ1X, θK is determined by Equation 9, and the compression start angle θ2Y is set by Equation 10. Therefore, θ1X and θ2Y cannot be optimized separately, and it is necessary to select θK that satisfies both.

  Table 1 shows an example of the mechanism of the second embodiment. The compression start delay θ2 is 44 to 65 degrees as the crankshaft rotation angle, but when the intake start angle θ1X is 34 to 40 degrees, the compression start The delay is 44-54 degrees, and rapid compression is improved.

The operation of the stopper latch 14 for stopping the + rotation of the secondary connecting rod 7 will be described in detail from the movement locus of the secondary connecting rod 7. FIG. 7B shows the movement trajectory of the crank arm 10 and the auxiliary connecting rod 7 in the expansion / exhaust stroke. In the exhaust stroke, the auxiliary connecting rod 7 is exhausted while rotating, and the state shown in FIG. Transition. When the crankshaft 11 further rotates from this point, the stop pawl 16 provided on the sub connecting rod 7 acts as a cam and rotates while pushing the stopper latch 14, and reaches the top dead center shown in FIG. Is completed.

When the crankshaft 11 is rotated by θ1X degrees from the top dead center state shown in FIG. 5B and the secondary connecting rod 7 reaches the state shown in FIG. The latch 14 suppresses + rotation and starts intake. Until the secondary connecting rod 7 and the main connecting rod 3 are aligned, + rotation of the secondary connecting rod 7 is suppressed. Thereafter, the secondary connecting rod reaches the bottom dead center shown in FIG. .

Similarly, in the compression stroke, when the crankshaft 11 rotates by θ2Y degrees from the bottom dead center and the secondary connecting rod 7 reaches the state shown in the schematic diagram of FIG. The stopper latch 14 prevents + rotation and starts compression. Until the secondary connecting rod 7 and the main connecting rod 3 are aligned, + rotation of the secondary connecting rod is suppressed. Thereafter, the secondary connecting rod reaches the top dead center while rotating negatively, and the compression is completed as shown in FIG. 7A. To do.

A vibration isolation mechanism according to a third embodiment of the present invention will be described.
The movement trajectory of the crank arm 10 and the sub connecting rod 7 in the second embodiment is shown in FIG. FIG. 7A shows a movement locus in the intake / compression stroke, and FIG. 7B shows a movement locus in the expansion / exhaust stroke. As is clear from the above, the movement trajectory of the sub connecting rod 7 in each stroke is completely different, and a balancing method such as attaching a weight on the opposite side of the crank pin, which is a conventional vibration isolating method, is insufficient. A dynamic balancing method synchronized with the movement trajectory is essential.

FIG. 8 shows a new vibration isolation mechanism and its configuration will be described. A gear (A) 17 rotatable around the crankshaft 11 is installed, and a gear (B) 18 centered on the crankpin 9 is arranged so as to rotate together with the auxiliary connecting rod 7, and both gears (A) 17, ( B) Engage 18. Further, a bracket arm 23 is added on the opposite side of the crank arm 10 and fixedly connected to the crankshaft 11. A gear (D) 24 is rotatably connected to the bracket arm 23 by a shaft 25, and both gears (A) 17, ( D) Anti-vibration balancing weight (1) 30 is meshed with 24 and is connected to the gear arm (D) 24 for dynamic anti-vibration balance with the main connecting rod 2 and the secondary connecting rod pin 7 etc. Balancing weight (2) 31 is installed.

Next, the operation of the new vibration isolation mechanism will be described with reference to FIG.
As shown in FIG. 8, the secondary connecting rod 7 is connected to the gear (B) 18 by the crankpin 9, and the gear (B) 18 rotates together with the secondary connecting rod 7, and the gear (D) is connected via the gear (A) 17. 24 also rotates in the same direction as the auxiliary connecting rod 7. The gear (B) 18 and the gear (D) 24 are set to have the same size so that the positional relationship between the anti-vibration balancing weight (1) 30 and the sub connecting rod 7 can always be maintained symmetrical with respect to the center of the crankshaft 11. .
As a result, the natural vibration of the crank mechanism is prevented by the anti-vibration balancing weight (2) 31, and the anti-vibration balancing is fixed to the gear (D) 24 against the dynamic vibration accompanying the rotation of the sub connecting rod 7. The weight (1) 30 enables dynamic vibration isolation.

FIG. 5 shows a mechanism for setting the intake start angle θ1X. With the addition of the vibration isolation mechanism shown in FIG. 8, it is not necessary to add an anti-rotation arm 13, and the anti-rotation device 12 is shown in FIGS. Will be installed in the position.
Although the detailed description is omitted, the stop pawl 16 is installed on the side surface of the gear (D) 24, and the rotation stopper 12 including the latch 14 and the spring 15 is fixedly installed on the bracket arm 23.
FIG. 10 is a cross-sectional view taken along line NN of the rotation stopper 12 of FIG.

FIG. 8 shows the basic configuration of the new vibration isolating mechanism. If the distance between the shafts of the gears cannot be obtained from the relationship between the diameter of the crankshaft 11 and the length of the crank arm 10, as shown in FIG. (A) 32 and chain wheel (B) 33 are connected by a chain 34, or a gear configuration is required as shown in FIG. 14, but details will be described later.

A stroke variable mechanism for changing the stroke of the intake stroke / compression stroke according to the fourth embodiment of the present invention is shown in FIGS.
As shown in FIG. 12, bracket arms 19, 23, and 26 are added and fixedly connected to the crankshaft 11, a gear (A) 17 that is rotatable around the crankshaft 11 is disposed, and the crankpin 9 is the center. The gear (B) 18 to be rotated with the auxiliary connecting rod 7 is arranged so that the gear (C1) 20 revolving around the gear (A) 17 is engaged with the gears (A) 17 and (B) 18. 19 is rotatably arranged by a shaft 22. Similarly, for the anti-vibration mechanism, the gear (D) 24 is rotatably installed on the bracket arm 23 by the shaft 25, and the gear (E1) 27 that revolves around the gear (A) 17 is replaced with the gear (A) 17, (D) The bracket arm 26 is rotatably arranged with a shaft 29 so as to mesh with the bracket 24. As for the intake stroke setting device 35 and the compression ratio setting device 45, only a schematic arrangement is shown in FIG.

In the basic configuration shown in FIGS. 12 and 13, when the distance between the shafts of the gears cannot be obtained due to the relationship between the diameter of the crankshaft 11 and the length of the crank arm 10, the configuration shown in FIGS. . The configuration will be described.
A gear (A) 17 that is rotatable around the crankshaft 11 is arranged, a shaft 22 is rotatably mounted on the bracket arm 19, and a gear (C1) 20 is fixed to the shaft 22 and meshed with the gear (A) 17. The gear (C2) 21 is fixed to the other end of the shaft 22, and the gear (B) 18 is integrated with the sub connecting rod 7 and meshed with the gear (C2) 21. Similarly, for the anti-vibration mechanism, the shaft 29 is rotatably mounted on the bracket arm 26, the gear (E1) 27 is fixed to the shaft 29 and meshed with the gear (A) 17, and the gear 29 is connected to the other end of the shaft 29. (E2) 28 is fixed and meshed with a gear (D) 24 that is rotatably installed on the bracket arm 23 by a shaft 25.

The principle of the operation of the variable stroke mechanism for changing the stroke of the suction stroke / compression stroke will be described with reference to the schematic diagram of FIG.
FIG. 16A shows the state of top dead center at the start of the intake stroke. From this, when the positive rotation of the gear (A) 17 is regulated to (180−α) degrees and the bottom dead center is reached, the planetary gear mechanism comprising the gear (A) 17, the gear (C) 20, and the gear (B) 18. As a result, the gear (B) 18 rotates by α degrees and the sub connecting rod 7 rotates by α degrees as shown in the broken line diagram. Therefore, the intake stroke can be minimized when α = 0 and maximized when α = 180.
That is, the basic principle (1) is to change the intake stroke by restricting the rotation angle of the gear (A) 17 in the rotation direction of the crankshaft.

Naturally, the design of the compression ratio when the intake stroke is made variable is premised on the maximum intake stroke to be applied, and the compression ratio decreases as the intake stroke decreases.
Therefore, it is necessary to change the compression stroke corresponding to the intake stroke.
FIG. 16B shows the state of the top dead center where the compression stroke is completed. The gear (A) 17 rotated by (180−α) degrees in the intake stroke + gear (A) 17 and the gear (C) in the compression stroke. ) It is rotated (180-α) degrees by the planetary gear mechanism comprising the gear 20 and the gear (B) 18 to return to the fixed point in the state of the top dead center shown in FIG. At the end of the compression stroke, the gear (B) 18 is rotated by -.degree., And the piston is pushed into the V.delta.X combustion chamber to increase the predetermined compression ratio. FIG. 16 (C) also shows the state of the top dead center after the compression stroke is completed. At the end of the compression stroke, the gear (B) 18 is rotated by β degrees and +, and the piston is pushed into the VδX combustion chamber to increase the predetermined compression. The ratio is ensured. That is, the rotation control of the gear (B) 18 is forced from the outside through the gear (A) 17 at the end of the compression stroke, the compression stroke is changed corresponding to the intake stroke, and the piston is pushed into the VδX combustion chamber and increased. The basic principle (2) is to secure a predetermined compression ratio by achieving the above.

Therefore, it is premised on that the gear (A) 17 rotates (180−α) degrees in the compression stroke, and the compression start delay control by suppressing the + rotation of the gear (A) 17 proposed in the second embodiment can be performed. Instead, it is defined by the compression start delay angle generated by the mechanism.

FIG. 17 shows the mechanism of the intake stroke setting device 35 and its configuration will be described. This figure shows a state in which the crankshaft is at top dead center, the exhaust stroke is completed, and the intake stroke is minimized, and the slide table such as the slide rack 36 and the intake slide rod 41 and the crank mechanism are illustrated. A cross-sectional view of the sliding table is shown in FIG. A rack tooth (A) 37 and a rack tooth (B) 38 are formed on both sides of the sliding rack 36, meshed with the gear (A) 17 at the lower end portion of the rack tooth (A) 37, and the fixed rack 39 is mounted on the rack tooth (B 38) is installed facing the pin 38, and the pinion 40 is meshed with the lower end of the rack tooth (B) 38 and the upper end of the fixed rack 39 so that the pinion 40 can be rotated on the shaft 42 fixed to the intake sliding rod 41. The intake slide rod 41 is raised or lowered in response to the rotation of the gear (A) 17, and the stopper 44 is raised or lowered by the stopper position setting control device 43 to set the lower position of the intake stroke slide rod 41. By specifying, the intake stroke is set.

The operation of the intake stroke setting device 35 will be described with reference to FIG. As described in the basic principle, the gear (A) 17 rotates 180 degrees at the maximum in the intake stroke. When the diameter of the pitch circle of the gear (A) 17 is Da, the sliding rack 36 meshed with the gear (A) 17 and the rack teeth (A) 37 is lowered by πDa / 2, and the rack teeth of the sliding rack 36 are lowered. (B) The pinion 40 meshed with the fixed rack 39 and the intake stroke slide rod 41 is lowered by πDa / 4.
Accordingly, the lowering amount of the intake sliding rod 41 is ½ of the lowering amount of the sliding rack 36, and the control responsiveness of the stopper position setting control device 43, which will be described later, is improved, but the control responsiveness is not hindered. For example, the rack and pinion mechanism may be omitted, and the amount of lowering of the sliding rack 36 may be controlled. The distance between the stopper 44 of the stopper position setting control device 43 and the intake sliding rod 41 is set as πDa / 4, and the stopper 44 is moved up and down by the stopper position setting control device 43 so that the intake sliding rod 41 is lowered. The basic action is to control the rotation of the sub connecting rod 7 to change the intake stroke by regulating the amount and regulating the rotation angle of the gear (A) 17.
In order to rotate the secondary connecting rod 7 by α degrees, the stopper 44 of the stopper position setting control device 43 has only to be raised by πDa / 4 × α / 180, and the intake stroke Stα at that time is determined by Equation 11 and the stopper The position setting control device 43 is numerically controlled.
The α value can be set within the range of 0 to 180 degrees. However, the rotation stop device 12 that defines the intake start crank rotation angle is installed, the rotation stopper angle is θK, and the intake start crank rotation angle is θ1X. The α value in this case is in the range of 0 to (180−θK−θ1X).

FIG. 17 shows the mechanism of the compression ratio setting device 45, and its configuration will be described.
This figure shows a state where the crankshaft is at the top dead center, the exhaust stroke is completed, and the compression stroke is not yet set, and sliding of the slide rod 49, the compression ratio setting rack 55, the compression stroke sliding rack 58, etc. The table and the crank mechanism are not shown, and the slide table is shown in FIG. A shaft fixed to the slide rod 49 by lowering the push rod 48 and the slide rod 49 connected to the push rod 48 by the mechanism of the cam 47 provided on the cam shaft 46 that rotates synchronously at a 1/2 angular velocity of the crankshaft 11. A pinion 51 is rotatably attached to 50, and when the cam 47 is released, the push rod 48 and the slide rod 49 are raised to a fixed position by the spring 52 and the spring mount 53, and the ascent limit is defined by the stopper 54. The compression ratio setting rack 55 is engaged with the pinion 51 at the upper end, and the compression ratio setting control device 56 is connected to the compression ratio setting rack 55 by connecting a rod 57 that expands and contracts. The lower end of the sliding rack 58 is engaged with the pinion 51, and the compression stroke sliding rack 58 is lowered twice as much as the downward stroke of the sliding rod 49 by the cam 47. The compression ratio setting control device 56 adjusts the expansion / contraction amount of the rod 57 up and down through the compression ratio setting rack 55 and the pinion 51 so that the lower end point of the compression sliding rack 58 corresponds to the intake stroke. If the receiver rod 59 fixedly installed on the gear (A) 17 is on the descending stroke line of the compression sliding rack 58 at the end of the compression stroke and the adjustment of the compression stroke is not necessary, the compression slide The compression ratio setting device 45 is disposed at a position where the moving rack 58 comes into contact with the receiver rod 59 at the lower end point, and the receiver rod 59 is pushed down by the lowering stroke of the compression sliding rack 58 to rotate the gear (A) 17 -by rotating. The connecting rod 7 is rotated-and the compression stroke is changed so as to obtain a predetermined compression ratio corresponding to the intake stroke.

FIG. 17 shows the mechanism of the compression ratio setting device 45 and its operation will be described.
Due to the mechanism of the cam 47 provided on the camshaft 46 that rotates synchronously with the ½ angular velocity of the crankshaft 11, the sliding rod 49 is always lowered together with the pinion 51 in the compression stroke, and the compression stroke is completed. When it starts to be released, the spring 52 moves up to a fixed position. The compression ratio setting rack 55 meshed with the pinion 51 is in a fixed state except during the setting operation, and the compression sliding rack 58 meshed with the pinion 51 descends twice the descending stroke of the sliding rod 49. .
When adjustment of the compression stroke is not required, the compression ratio setting device 45 is disposed at a position where it comes into contact with the receiver rod 59 at the lower end of the compression sliding rack 58. When the compression ratio setting rack 55 is raised by the compression ratio setting control device SδX, the compression sliding rack 58 is lowered by SδX through the pinion 51, and when the compression stroke is completed, the compression sliding rack 58 pushes SδX with the receiver rod 59 as a straight line. Rotating motion, the gear (A) 17 is rotated, the auxiliary connecting rod 7 is rotated through the gear (B) 18 and the gear (C1) 20, and the compression stroke is increased. The piston is pushed into the VδX combustion chamber so as to obtain a compression ratio of
(Details of the action of the compression sliding rack 58 and the receiver rod 59 will be described later).
The combustion chamber volume VC is designed with the maximum intake stroke to be applied to ensure a predetermined compression ratio ε, and when the intake stroke is reduced, the compression stroke is increased correspondingly to maintain the predetermined compression ratio ε.

When the compression ratio can be increased to the compression ignition range and the engine is combined with the spark ignition method and the compression ignition method, the volume Vc of the combustion chamber is designed with the maximum intake stroke applied as the spark ignition engine. When a predetermined compression ratio is ensured and the engine is operated as a compression ignition engine, the compression stroke is changed so as to obtain a predetermined compression ratio corresponding to the intake stroke.

The control amount SδX of the compression ratio setting control device 56 for obtaining a predetermined compression ratio corresponding to the intake stroke is determined by Equation 12, and the compression ratio setting control device 56 is numerically controlled.

For the method of rotating the gear (A) 17 + and rotating the auxiliary connecting rod 7 + via the gear (B) 18 and the gear (C1) 20, the arrangement of the compression ratio setting device 45 may be changed, as shown in FIG. The push-in of the receiver rod 59 shown in FIG. 17 may be arranged to be pushed up, or may be arranged to be pushed down to a position where the return amount of the intake sliding rod 41 shown in FIG.

A control method example of the intake stroke setting device 35 will be described. To determine the intake capacity by changing the intake stroke according to the operating conditions, if the rotation angle α of the sub connecting rod 7 at the bottom dead center is set, the intake stroke Stα is defined by Equation 11, and the stopper position setting control 43 is numerically controlled. To do. If the intake capacity is automatically selected, the accelerator depressing amount and depressing acceleration are detected, and the intake stroke is increased when there is no change in the depressing amount and the engine speed decreases and when the decelerating speed exceeds the reference acceleration. It is conceivable to reduce the intake stroke when the air pressure rises.

A control method example of the compression ratio setting device 45 will be described. In order to ensure a predetermined compression ratio according to the intake stroke, the pushing amount SδX of the receiver rod 59 is defined by Equation 12 when the operation intake stroke SX is performed, and the compression ratio setting control device 56 is numerically controlled.
The compression ratio can be changed from the spark ignition region to the compression ignition region, and it is possible to set the proper use of the gasoline engine or the diesel engine.

The stroke variable mechanism that is the fourth embodiment of the present invention that changes the stroke of the suction / compression stroke has been described above. The following two points will be supplemented and verified.

First, the linear descent of the compression sliding rack 58 is converted into the rotational movement of the receiver rod 59, and it is verified whether the secondary connecting rod 7 can be rotated.

FIG. 19A shows the operation stroke of the compression sliding rack 58 in the compression stroke at the applied maximum intake stroke that does not require the compression ratio setting control. Even if the stroke is lowered, it is only in contact with the receiver rod 59, and the receiver rod 59 is not pushed and rotated.

FIG. 19B shows a state in which the compression sliding rack 58 has been lowered by the compression ratio setting control device 56 at the minimum intake stroke, and the compression sliding rack 58 descends a predetermined stroke from this point and the receiver rod 59. Is pushed and the gear (A) 17 is rotated by βmax-. It is a problem whether the receiver rod 59 can be pushed in without the head part of the compression sliding rack 58 interfering with the receiver rod 59 during the lowering.

FIG. 20 is an enlarged view of the operation transition in the section of 1.2 degrees as the crankshaft rotation angle at which the head portion of the compression sliding rack 58 approaches the receiver rod 59 in the lowering process of the compression sliding rack 58. However, as is apparent from the figure, interference can be avoided by optimizing the size and shape of the head portion and the inclination angle θr of the downward stroke of the compression sliding rack 58, and there is no problem.

The second problem is whether or not the secondary connecting rod 7 can be shifted to the expansion stroke without any problem after the sub connecting rod 7 is rotated by-or + at the end of the compression stroke to secure a predetermined compression ratio.
When the cam mechanisms 46 and 47 of the compression setting device 45 are set as shown in FIG. 21, the rotation of the sub connecting rod 7 in the expansion stroke after the sub connecting rod 7 is rotated-or + to ensure a predetermined compression ratio. The angle β is determined by Equation 13.
The transition of the rotation angle β of the crankshaft relative to the rotation angle β of the auxiliary connecting rod 7 in the expansion stroke is shown in FIG.

The transition process of the rotation angle β of the auxiliary connecting rod 7 in the expansion stroke will be described with reference to FIG.
The rotation angle β of the secondary connecting rod 7 at the end of the compression stroke in the applied maximum intake stroke that does not require the compression ratio setting control is 0 °, and the transition line of β = 0 ° is the case where the compression ratio control is unnecessary. The intersection of the transition line in the case of β ≠ 0 ° and the transition line in β = 0 ° is the operation end point of the compression setting device 45, and thereafter the expansion stroke proceeds along the transition line of β = 0 °. The crankshaft rotation angle at this intersection can be adjusted by the tilt angle θb of the head of the push rod 48 and the width KB of the tilted portion, and can be set to the optimum point.

The case where β ≦ 0 ° in which the secondary connecting rod 7 is rotated is verified. As shown in FIG. 16B, the state of the top dead center where the compression stroke has been completed is determined by the rotation of the crank arm 10 regardless of whether the ignition is completed before the top dead center or after the top dead center. It is clear that it can be converted into force and can be transferred to the expansion stroke without problems.
Until the operation end point of the compression setting device 45, a part of the expansion force acts as a force for rotating the auxiliary connecting rod 7 and applies a load to the gear (A) 17, etc., and the operation end point is preferably short. However, if it is too short, the compression ratio is lowered early, and optimization is necessary in view of the ignition delay.

The case where β ≧ 0 ° when the sub connecting rod 7 is rotated + is verified.
As shown in FIG. 16C, the top dead center after the compression stroke has been completed is that the expansion force can be converted into the rotational force of the crank arm 10 because the connecting rod pin 8 is located at the center point between the piston pin 3 and the crankshaft 111. It is from the time when it crosses the connected center line and is shown in FIG. 22 as “θ where the connecting rod pin coordinate Y = 0”, and θ is 0 to 14 °. Accordingly, the ignition cannot be completed before the top dead center, and must be completed after the top dead center. The head tilt angle θB of the push rod 48 is set and adjusted to “connect rod pin coordinate Y = 0”. It is indispensable to have an optimized design that completes ignition at the same time. However, the compression ratio cannot be lowered until ignition is completed, and there is no advantage of the compression ratio setting control method in which the secondary connecting rod 7 is rotated in the positive direction. As long as there is not, the method of β ≦ 0 ° with -rotation is optimal.

FIG. 2 is a schematic diagram of a mechanism for increasing the length of a connecting rod at a bottom dead center, showing the crank mechanism according to the first embodiment. It is the schematic which shows the crank mechanism which concerns on 2nd Embodiment, and shows the relationship between the piston position and stroke stroke in a top dead center and a bottom dead center. It is a schematic diagram which shows the action | operation of the crank arm, the main connecting rod, and the sub connecting rod in the intake / compression stroke and the expansion / exhaust stroke of the mechanism of FIG. It is the graph which showed the displacement of the piston position in the intake / compression / expansion / exhaust stroke of the mechanism of FIGS. It is a figure which shows the setting mechanism of an intake and compression start crankshaft angle. FIG. 6 is a schematic diagram showing the relationship between the setting value of the setting mechanism of FIG. 5 and the crankshaft angle at the start of intake and compression. It is the graph which showed the movement locus | trajectory of the crank arm and the sub connecting rod in the intake / compression / expansion / exhaust stroke of the second embodiment. It is the schematic which shows the new vibration isolating mechanism which is 3rd Embodiment. It is a top view of FIG. It is NN sectional drawing which concerns on the gearwheel (D) rotation stopper in FIG. It is the figure which comprised the new vibration isolating mechanism shown in FIG. 8 with the chain and the chain wheel. It is a figure which shows the stroke variable mechanism of the intake stroke and compression stroke which is 4th Embodiment. FIG. 13 is a plan view of FIG. 12. It is a figure which shows the gear arrangement | positioning and structure when the center distance of a gearwheel cannot be taken in the mechanism of FIG. FIG. 15 is a plan view of FIG. 14. It is a schematic diagram for demonstrating the principle of action of the stroke variable mechanism of the intake stroke / compression stroke of FIG. It is a figure which shows the mechanism of the setting apparatus of an intake stroke and a compression stroke. It is RR, SS, TT sectional drawing concerning the slide stand in FIG. It is the graph which showed transition of an operation and rotation of the head of a compression sliding rack, and a receiver rod. It is the graph which showed transition of an operation and rotation of the specific section where the head of a compression sliding rack and a receiver rod approach closest first. FIG. 4 shows an example of the cam mechanism of a compression setting device for verifying whether or not the expansion stroke can be shifted to after changing the stroke of the compression stroke. The graph which showed transition of the rotation angle of the sub connecting rod in an expansion stroke when the double compression rod crank mechanism specification (example) shown in Table 2 has secured a predetermined compression ratio with the compression stroke setting device of the cam mechanism of FIG. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston 2 Main connecting rod 3 Piston pin 4 Connecting cylinder 5 End stopper 6 Connecting piston 7 Sub connecting rod 8 Connecting rod pin 9 Crank pin 10 Crank arm 11 Crank shaft 12 Anti-rotation device 13 Anti-rotation arm 14 Stop latch 15 Spring 16 Stop pawl 17 Gear (A)
18 Gear (B)
19 Bracket arm 20 Gear (C1)
21 Gear (C2)
22 Shaft 23 Bracket arm 24 Gear (D)
25 Shaft 26 Bracket arm 27 Gear (E1)
28 Gear (E2)
29 Shaft 30 Anti-vibration balancing weight (1)
31 Anti-vibration balancing weight (2)
32 Chain car (A)
33 Chain car (B)
34 Chain 35 Intake stroke setting device 36 Sliding rack 37 Rack teeth (A)
38 rack teeth (B)
39 Fixed rack 40 Pinion 41 Sliding rod 42 Shaft 43 Stopper position setting control device 44 Stopper 45 Compression ratio setting device 46 Cam shaft 47 Cam 48 Push rod 49 Sliding rod 50 Shaft 51 Pinion 52 Spring 53 Spring mount 54 Stopper 55 Compression ratio Setting rack 56 Compression ratio setting control device 57 Rod 58 Compression sliding rack 59 Receiver rod 61 Slide stand (1)
62 Slide base (2)
63 Slide base (3)
KL Specified sliding length of piston pin 3 or connecting piston 6 θk Rotation stopper angle θ1X Intake start crankshaft rotation angle θ2Y Compression start crankshaft rotation angle α Rotation angle of secondary connecting rod at bottom dead center (= gear (A) 17 rotation angle)
β Rotation angle of secondary connecting rod at top dead center (= rotation angle of gear (A) 17)

Claims (4)

This is a reciprocating engine crank mechanism. The connecting rod is connected to the piston with a piston pin, the other end of the connecting rod is connected to the crank arm with a crank pin, the connecting rod is expanded and contracted, and the intake and compression strokes are expanded according to the length of expansion and contraction. -Crank mechanism that is smaller than the exhaust stroke. A reciprocating engine crank mechanism similar to claim 1, wherein the main connecting rod is connected to the piston by a piston pin, the other end of the main connecting rod is connected to the sub connecting rod by a connecting rod pin, and the other end of the auxiliary connecting rod is cranked. A double connecting rod crank mechanism that is connected to the crank arm with a pin and the suction / compression stroke is made smaller than the expansion / exhaust stroke according to the length of the sub connecting rod. In the crank mechanism, a gear A that is rotatable around a crankshaft is disposed, a gear B that is centered on a connecting rod pin is disposed so as to rotate together with the auxiliary connecting rod, and a gear C that revolves around the gear A is disposed on the gear A. A variable stroke mechanism which is arranged so as to mesh with B and rotates the sub connecting rod by controlling the rotation of the gear A from the outside during the intake stroke and the compression stroke, thereby changing the stroke of the intake stroke and the compression stroke. 4. The mechanism according to claim 2, wherein one or more bracket arms are added to the crankshaft, and an anti-vibration balancing weight is rotatably connected to the arm by a pin. Anti-vibration mechanism that rotates symmetrically.

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