JP2007224787A - Exhaust acceleration system for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust acceleration system for an engine reducing quantity of exhaust gas staying in a combustion chamber after exhaust stroke. <P>SOLUTION: This system is provided with a piston 18 having a depressed part formed on a top part, a projection member 88 stored in the depressed part 86 in such a manner that the same can project out of the top part of the piston 18 and an energizing means 90 energizing at least a part of the projection member 88 to project the same out of the depressed part 86 at least during exhaust stroke. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine exhaust acceleration system that promotes exhaust gas exhaust by reducing a combustion chamber volume at least in an exhaust stroke.

  Conventionally, in order to avoid knocking or the like, a movable member that is supported by a spring in the recess at the top of the piston and moves in the cylinder axis direction in the recess is provided, and this is detected when the pressure in the combustion chamber (combustion pressure) increases. An engine is known in which a movable member is pushed down to change the combustion chamber volume (see Patent Document 1). In this case, it is disclosed that an annular space is provided around the movable member, and oil is supplied to the annular space so as to be able to enter and exit in order to keep the position of the movable member against the combustion pressure. Yes.

  In addition, the cylinder groove provided in the center of the cavity at the top of the piston is equipped with a variable piston that is hydraulically actuated and biased downward by a spring. At low speed, the variable piston is raised by hydraulic pressure, and the compression ratio and swirl ratio are increased. On the other hand, a variable compression ratio piston is disclosed in which the hydraulic pressure is lowered at high speeds to reduce the compression ratio and swirl ratio (see Patent Document 2).

JP-T-2004-522042 Japanese Patent Laid-Open No. 5-272404

  Exhaust gas may remain in the combustion chamber after the exhaust stroke, and if the process proceeds to the next cycle, the amount of air that can be sucked in the intake stroke decreases. There is. Furthermore, the temperature of the compressed air or the compressed air-fuel mixture rises due to the residual gas, and so-called knocking may occur, which is not preferable.

  On the other hand, the one described in Patent Document 1 prevents the combustion pressure from becoming too high, and the one described in Patent Document 2 makes the compression ratio and swirl ratio variable according to the engine speed. Therefore, the amount of exhaust gas remaining in the combustion chamber after the exhaust stroke is not reduced.

  Therefore, an object of the present invention is to provide an engine exhaust promotion system that reduces the amount of exhaust gas remaining in a combustion chamber after an exhaust stroke.

  In order to solve the above-described problems, an engine exhaust promotion system according to the present invention includes a piston having a recess formed at the top, a projecting member accommodated in the recess so as to project from the top of the piston, Biasing means for biasing at least a part of the recess to protrude at least during the exhaust stroke.

  With the above configuration, at least in the exhaust stroke, at least a part of the projecting member is projected from the top of the piston, so that the combustion chamber volume is reduced. Therefore, in the exhaust stroke, it is promoted that an amount of exhaust gas corresponding to at least a part of the protruding projecting member is discharged to the exhaust passage. As a result, the amount of exhaust gas remaining in the combustion chamber after the exhaust stroke is reduced.

  The biasing means preferably includes a spring that expands and contracts in the cylinder axis direction. Due to the force of the spring, the projecting member is urged so that at least a part of the projecting member projects from the recess at least in the exhaust stroke.

  Desirably, the piston is provided with at least one hole communicating the compartment formed by the projecting member and the recess and the piston bottom side outer surface. Thereby, the fluid such as air and oil can enter and exit from the outer surface on the piston bottom side to the compartment, and the movement of the protruding member in the concave portion becomes smooth.

  Further, in the recess, a first compartment chamber in which hydraulic pressure for urging the protruding member toward the top side of the piston is supplied via the first oil passage, and the protruding member is positioned on the bottom side of the piston. A second compartment is formed in which the hydraulic pressure to be energized is supplied via the second oil passage, and the energizing means sets the first compartment to a hydraulic pressure supply state during an exhaust stroke, and at least the protruding member It is preferable that a part is protruded from the recess and the second partition chamber is in a hydraulic pressure supply state at least during the intake stroke other than the exhaust stroke so that the protruding member is accommodated in the recess. Thereby, it becomes possible to move a protrusion member using oil_pressure | hydraulic. In the exhaust stroke, hydraulic pressure is supplied to the first compartment via the first oil passage, the first compartment is brought into a hydraulic pressure supply state, and at least a part of the projecting member projects from the recess. Therefore, the combustion chamber volume in the exhaust stroke is reduced, and exhaust of exhaust gas is promoted. Further, at least in the intake stroke other than the exhaust stroke, the hydraulic pressure is supplied to the second compartment via the second oil passage, the second compartment is brought into a hydraulic pressure supply state, and the protruding member is accommodated in the recess. Become. Therefore, a sufficient amount of air can be sucked in the intake stroke.

  Further, the connecting rod includes a first rod oil passage that forms part of the first oil passage, a second rod oil passage that forms part of the second oil passage, the first rod oil passage, and A rod pin hole located in the middle of the second rod oil passage is formed, and the rod pin inserted into the rod pin hole has a first rod pin oil passage that opens the first rod oil passage in the exhaust stroke; A second rod pin oil passage that opens a two-rod oil passage in at least the intake stroke other than the exhaust stroke, and at least partially defines a gear that rotates the rod pin in response to rotation of a crankshaft. When the crankshaft rotates twice by the driving mechanism, it is preferable to rotate the crankshaft once. Thus, the first oil passage and the second oil passage are communicated with the first compartment and the second compartment of the piston via the connecting rod. In addition, the first rod pin oil passage and the second rod pin oil passage are at least partially defined by the rod pin, and the rod pin is rotated once when the crankshaft rotates twice. Therefore, the rotating rod pin causes an exhaust stroke in a four-cycle engine. The first rod oil passage is opened, and the second rod oil passage is opened at least in the intake stroke other than the exhaust stroke.

  The crank pin of the crankshaft is provided with a supply switching means for switching a hydraulic pressure supply path to the first oil path and the second oil path, and the supply switching means has the piston at the top dead center. When the first oil passage is in a state in which the hydraulic pressure can be supplied and the second oil passage is in a state in which the hydraulic pressure cannot be supplied when the piston is descending toward the bottom dead center In addition, it is preferable that the second oil passage is in a state where hydraulic pressure can be supplied and the first oil passage is in a state where hydraulic pressure cannot be supplied. As a result, in the exhaust stroke, the first oil passage is brought into a state where hydraulic pressure can be supplied, and the second oil passage is brought into a state where hydraulic pressure cannot be supplied. In the intake stroke, the second oil passage is brought into a state where hydraulic pressure can be supplied, and the first oil passage is brought into a state where hydraulic pressure cannot be supplied.

  More preferably, a variable valve mechanism that makes the valve timing or lift amount of at least one of the intake and exhaust valves variable, a third oil passage communicating with the second compartment, and a third oil passage from the hydraulic pressure supply means An oil control valve that switches a supply path to the first and second oil passages, a determination unit that determines whether an overlap amount of the intake and exhaust valves exceeds a predetermined value, and the overlap by the determination unit And a switching control means for controlling the oil control valve to switch to the supply path to the third oil path when it is determined that the amount exceeds the predetermined value. As a result, when the overlap amount of the intake and exhaust valves exceeds a predetermined value, the hydraulic pressure is not supplied to the first oil passage and the second oil passage, and the hydraulic pressure is supplied to the third oil passage. The hydraulic pressure is supplied to the second compartment, and the second compartment is in a hydraulic pressure supply state. Accordingly, the protruding member is accommodated in the concave portion at the top of the piston.

  An engine exhaust promotion system according to the present invention will be described in detail with reference to the drawings based on an embodiment.

  First, a first embodiment of an engine exhaust promotion system according to the present invention will be described with reference to FIGS. The concept of the engine system in the first embodiment is shown in FIG. FIG. 2 is an enlarged view of the piston in FIG. 1, and is a view in which the piston is rotated 90 ° around its axis. FIG. 3 is a view for explaining the movement of the protruding member in the piston.

  The engine 10 includes a cylinder block 12, a cylinder head 14, and an oil pan 15 as main outer members. A piston 18 is provided in the cylinder 16 of the cylinder block 12 so as to reciprocate. A combustion chamber 20 is formed above the piston 18 in the cylinder 16.

  The piston 18 is connected to the connecting rod 22 via a piston pin 28 that is inserted into the piston pin hole 26 of the small end 24 of the connecting rod 22. The connecting rod 22 includes the small end portion 24, the large end portion 30, and a connecting portion 32 for connecting them. A crankpin hole 34 is provided in the large end 30, and a crankpin 38 of a crankshaft 36 is inserted into the crankpin hole 34. Therefore, the reciprocating motion of the piston 18 in the cylinder 16 is converted into the rotational motion of the crankshaft 36 via the connecting rod 22.

  The cylinder head 14 formed with the intake port 40 and the exhaust port 42 respectively facing the combustion chamber 20 has a valve operating mechanism 48 for driving the intake valve 44 and the exhaust valve 46 and ignition for igniting the air-fuel mixture in the combustion chamber 20. And an igniter 52 for generating a spark in the spark plug 50 is mounted. Here, the engine 10 is an in-cylinder injection type in which gasoline as fuel is directly injected into the combustion chamber 20 from the fuel injection valve 54 and ignited by the spark plug 50.

  The valve operating mechanism 48 can freely change the phase and lift amount of the operating angle (operating angle) of the intake valve 44 and the exhaust valve 46, that is, can freely change their valve timing, and can freely change their lift amount. The variable valve mechanism is variable. Although not shown, the valve mechanism 48 moves the intake valve 44 and the exhaust valve 46 by the electromagnetic force of the electromagnetic coil, and the intake and exhaust valves 44 and 46 are electromagnetically driven valves. Therefore, the phase of the working angle and the lift amount can be freely changed by the electromagnetic force of the energization drive controlled by the electromagnetic coils of the intake valve 44 and the exhaust valve 46.

  At the upstream end side of the intake pipe 58 connected to the cylinder head 14 so as to communicate with the intake port 40 and defining the intake passage 56 together with the intake port 40, dust and the like contained in the atmosphere are removed to remove the intake passage 56. An air cleaner 60 is provided for guiding the air. A portion of the intake pipe 58 that is located downstream of the air cleaner 60 and upstream of the surge tank 62 is opened by a throttle actuator 66 based on the amount of depression of an accelerator pedal 64 that is operated by the driver. An intake throttle valve whose degree is adjusted, that is, an electronically controlled throttle valve 68 is incorporated. However, the depression operation of the accelerator pedal 64 and the opening / closing operation of the throttle valve 68 can be separated and electronically controlled.

  In the middle of the exhaust pipe 72 connected to the cylinder head 14 so as to communicate with the exhaust port 42 and defining the exhaust passage 70 together with the exhaust port 42, harmful substances generated by combustion of the air-fuel mixture in the combustion chamber 20 are present. A detoxifying catalyst 74 is incorporated.

  Therefore, when air passes through the air cleaner 60 and is supplied from the intake pipe 58 into the combustion chamber 20 in the intake stroke, an air-fuel mixture is formed with the fuel injected from the fuel injection valve 54 into the combustion chamber 20. The air-fuel mixture is compressed in the compression stroke and ignited by the spark of the spark plug 50. This leads to a combustion / expansion stroke, combustion occurs in the air-fuel mixture, expands, and pushes down the piston 18. The exhaust gas thus generated is pushed out from the exhaust valve 46 in the exhaust stroke, and is exhausted from the exhaust pipe 72 through the catalyst 74 to the atmosphere.

  The engine 10 includes various sensors that detect various values and output them to an electronic control unit (hereinafter referred to as ECU) 76. Specifically, an intake pressure sensor 78 that detects the pressure of the air in the intake pipe 58, that is, the intake pressure, is provided. Further, an accelerator position sensor 80 for detecting a position corresponding to the depression amount of the accelerator pedal 64 operated by the driver is provided. Further, a throttle position sensor 82 for detecting the opening degree of the throttle valve 68 is provided. A crank position sensor 84 that detects a crank rotation signal of the crankshaft 36 is attached to the cylinder block 12 in which the piston 18 reciprocates. Here, the crank position sensor 84 is also used as an engine speed sensor.

  The ECU 76 is constituted by a microcomputer including a CPU, ROM, RAM, A / D converter, input interface, output interface, and the like. The above various sensors are electrically connected to the input interface. Based on detection signals from these various sensors and the like, the ECU 76 electrically outputs a signal from the output interface so that the engine 10 can be smoothly operated according to a preset program, and the valve operating mechanism 48. The operation of the igniter 52, the fuel injection valve 54, the throttle actuator 66, and the like is controlled.

  In the normal operation, the engine 10 opens the throttle based on the intake pressure based on the output value from the intake pressure sensor 78, the accelerator opening based on the output value from the accelerator position sensor 80, and the output value from the throttle position sensor 82. The fuel injection amount, the fuel injection timing, the ignition timing, and the like are set based on the engine speed and the engine speed based on the output value from the crank position sensor 84, that is, the operating state represented by the engine load and the engine speed. At that time, the correction is made according to the engine coolant temperature and the like, and the fuel injection valve 54, the spark plug 50, and the like are controlled based on the corrected fuel injection amount, fuel injection timing, and ignition timing.

  In the engine 10, the valve mechanism 48 is controlled by the ECU 76 so that a predetermined amount of overlap between the intake valve 44 and the exhaust valve 46 occurs when the engine speed is high. Thereby, the air is effectively guided into the combustion chamber 20. On the other hand, when the engine speed is low, the amount of overlap is larger than when the engine speed is high, in order to prevent the exhaust gas from flowing backward from the exhaust passage 70 into the combustion chamber 20 and causing unstable combustion. The valve operating mechanism 48 is controlled so that there is less or no overlap.

  In the engine 10, as described above, the valve operating mechanism 48 allows the intake to be exhausted so that a predetermined amount of overlap occurs when the engine speed is high, and the overlap amount decreases when the engine speed is low. The valve timing and lift amount of the valves 44 and 46 are continuously changed. Therefore, it is possible to sufficiently bring out the engine performance in the entire rotation region.

  By the way, the piston 18 has a recess 86 formed at the top thereof. The recess 86 accommodates a projecting member 88 that can project at least a part from the top of the piston 18. Further, a spring 90 that urges the protruding member 88 toward the combustion chamber 20 is provided in the recessed portion 86 so that a part of the protruding member 88 protrudes from the recessed portion 86 in the exhaust stroke. Therefore, a part of the projecting member 88 can be projected from the opening 92 of the recess 86 as shown in FIGS. That is, in the first embodiment, the spring 90 constitutes an urging means for urging the projecting member 88 so that at least a part of the projecting member 88 projects from the recess 86 at least in the exhaust stroke.

  The protruding member 88 includes a columnar portion 94 and a flange portion 96, and the tip of the columnar portion 94 can protrude from the recessed portion 86. In FIG. 2, the tip of the columnar portion 94 protrudes from the recess 86. On the other hand, the piston 18 has an annular portion 100 that reduces the diameter of the opening 92 of the recess 86. Since the flange portion 96 and the annular portion 100 are engaged with each other, the protruding member 88 is prevented from coming off from the concave portion 86.

  The spring 90 is a spring that supports the protruding member 88 and expands and contracts in the direction of the axis α of the cylinder 16 so that the tip of the columnar portion 94 that is a part of the protruding member 88 protrudes from the recessed portion 86. Due to the spring 90 connecting the bottom surface 102 of the projecting member 88 and the bottom 104 of the recess 86, the projecting member 88 is always subjected to a spring force and is urged toward the combustion chamber 20. However, the spring 90 has a spring force F <b> 1 that pushes up the protruding member 88 at least in the exhaust stroke, and the tip of the columnar portion 94 protrudes from the opening 92 of the recess 86. This spring force F1 is set to be smaller than an explosion force that pushes down the piston 18 in the combustion / expansion stroke, and therefore the protruding member 88 is accommodated in the combustion chamber 20 in the combustion / expansion stroke.

  As shown in FIG. 2, the seal ring 106 is provided between the radial inner side of the opening 92 of the concave portion 86 and the radial outer side of the columnar portion 94 of the protruding member 88, and is formed by the concave portion 86 and the protruding member 88. The airtightness of the top side of the compartment 108 to be partitioned is maintained. Thereby, inflow of the combustion gas etc. to the compartment 108 is prevented.

  The projecting member 88 can project from the recess 86 and slides between the seal ring 106. In the first embodiment, the compartment 108 formed by the projecting member 88 and the recess 86 is formed so that the movement of the projecting member 88 is smooth in a state where the sealing property of the compartment 108 is achieved by the seal ring 106. The piston 18 is provided with a hole 110 that communicates with the bottom side outer surface of the piston 18. In FIG. 1 and FIG. 2, one hole 110 is drawn, but a plurality of holes 110 are provided.

  The effects of the engine exhaust promotion system of the first embodiment having the above-described configuration will be described below with reference to FIG. FIG. 3 shows the movement of the protruding member 88. The right half shows the position of the protruding member 88 in the compression stroke and the combustion / expansion stroke, and the left half shows the position of the protruding member 88 in the intake stroke and exhaust stroke. Is schematically represented. However, for convenience of explanation, the position of the hole 110 in FIG. 3 is shifted from the position of the hole 110 shown in FIG. The same applies to the spring 90.

  In the intake stroke, the exhaust valve 46 is closed and the intake valve 44 is opened, and the piston 18 is lowered, so that the cylinder 16 has a negative pressure, and air is sucked from the intake valve 44. At this time, the pressure in the cylinder 16 is not high, and the projecting member 88 is biased toward the combustion chamber 20 by the spring 90, and the tip of the columnar portion 94 of the projecting member 88 projects from the opening 92 of the recess 86 (see FIG. 3).

  Next, in the compression stroke, the intake / exhaust valves 44 and 46 are closed, fuel is injected into the combustion chamber 20, and the piston 18 reverses from the descending and rises, compressing the volume of the air-fuel mixture in the cylinder 16, The air-fuel mixture is confined in the combustion chamber 20. At this time, since the air-fuel mixture is compressed, the pressure in the cylinder 16 is increased, the compression force F2 exceeds the spring force F1 of the spring 90, and the protruding member 88 is accommodated in the recess 86. (See FIG. 3).

  When the piston 18 reaches near the top dead center, the air-fuel mixture is ignited by the spark plug 50. As the air-fuel mixture burns, the gas expands and pushes down the piston 18. Since the pressing force F3 due to this combustion pressure is larger than the spring force F1 of the spring 90, the protruding member 88 is generally kept in the recess 86 during the combustion / expansion stroke.

  Thereafter, in the exhaust stroke, the exhaust valve 46 is opened while the intake valve 44 is closed, the piston 18 lowered by the combustion is reversed, and the combustion gas is pushed out from the exhaust valve 46. At this time, the inside of the cylinder 16 communicates with the exhaust passage 70, and the pressure in the cylinder 16 is less than the spring force F 1 of the spring 90. Therefore, a part of the protruding member 88 protrudes from the recess 86 of the piston 18 toward the combustion chamber 20 to reduce the volume in the cylinder 16, that is, in the combustion chamber 20 (see FIG. 3). Therefore, the exhaust gas is positively pushed out from the cylinder 16.

  Thus, in the compression stroke and the combustion / expansion stroke, the projecting member 88 is accommodated in the recess 86, and the piston top is substantially flat like the conventional piston 18, so that the compression ratio as in a normal engine can be realized. . On the other hand, in the exhaust stroke, a part of the protruding member protrudes toward the combustion chamber 20, so that more exhaust gas is pushed out to the exhaust passage 70 in the exhaust stroke, and at least a part of the protruding member 88 protrudes. The amount of exhaust gas remaining in the cylinder 16 after the exhaust stroke is reduced compared to the case where the exhaust stroke is not performed. That is, the exhaust of the combustion gas from the cylinder 16 is promoted. Therefore, more air can be inhaled in the next intake stroke. Further, since the amount of remaining exhaust gas is reduced, the temperature of the compressed mixture is excessively increased by the remaining exhaust gas, and the possibility of so-called knocking is reduced.

  Since the piston 18 is provided with a hole 110 that communicates the compartment 108 formed by the projecting member 88 and the recess 86 and the piston 18 bottom side outer surface, the compartment 18 is provided from the piston 18 bottom side outer surface. Fluid such as air, oil, and oil mist can enter and exit from 108, and the movement of the projecting member 88 in the recess 86 becomes smooth.

  As mentioned above, although this invention was demonstrated based on said 1st embodiment, the deformation | transformation and change are accept | permitted in this invention. The projecting member 88 may have any shape, number, or the like, but at least a part of the projecting member 88 may project from the recess 86 at least during the exhaust stroke, and the entire projecting member 88 may project from the recess 86. In particular, in order to prevent interference between the intake and exhaust valves 44 and 46 and the protruding member 88, for example, in the case of a four-valve engine, the protruding member 88 corresponding to the protruding portion of the intake and exhaust valves 44 and 46 to the combustion chamber 20 is provided. It is desirable that the cross section of the protruding portion of the protruding member cut by a plane orthogonal to the axis α of the cylinder 16 is a substantially cross shape with the portion being a recess. Further, the shape, position, and number of the spring 90 and the shape, position, and number of the hole 110 are not limited. It is sufficient to have at least one of each.

  The present invention is not limited to the in-cylinder injection type engine as described above, and can be applied to various engines such as a port injection type engine and a diesel engine. The fuel used is not limited to gasoline, but may be alcohol fuel, LPG (liquefied natural gas), or the like.

  Furthermore, in the first embodiment, the spring 90 is used as the biasing means, but the present invention is not limited to this. Any spring can be used. In addition to the spring, other means may be provided. Alternatively, the urging means may be constituted only by other means. In the second embodiment to be described later, in addition to the spring 90, the protruding member 88 is moved using hydraulic pressure as another means.

  Next, a second embodiment of the engine exhaust promotion system according to the present invention will be described with reference to the drawings. The engine exhaust promotion system of the second embodiment is mainly different from the engine exhaust promotion system of the first embodiment in that the urging means operates the protruding member 88 using hydraulic pressure. Therefore, this difference and the difference in the configuration of the engine system corresponding to this difference will be described below, and the same thing as that described in the first embodiment and its modification will be omitted. To do. In addition, about the same thing as the component of the engine system of said 1st embodiment, description is abbreviate | omitted using the same code | symbol.

  As described above, the projecting member 88 includes the columnar portion 94 and the flange portion 96, and the flange portion 96 is convex in the direction perpendicular to the axis α of the cylinder 16 over the entire circumference on the bottom side of the columnar portion 94. It is extended. Therefore, the compartment 108 is roughly divided into the first compartment 112 and the second compartment 114 in the direction of the axis α by the flange portion 96. The first partition chamber 112 is supplied with hydraulic pressure for biasing the protruding member 88 toward the top portion 18a of the piston 18 via the first oil passage A, and the protruding member 88 is connected to the piston 18 in the second partition chamber 114. The hydraulic pressure that urges the bottom 18b is supplied via the second oil passage B.

  Both the first compartment 112 and the second compartment 114 are supplied with hydraulic pressure by the action of an oil pump 116 that is a hydraulic supply means. The oil pump 116 is connected to the crankshaft 36 via a bearing 117 integrated with the cylinder block 12 and the like. The bearing portion 117 is a crank cap or the like. The oil pump 116 is a known four-tooth five-leaf trochoid pump. By the action of the oil pump 116, although not shown, the lubricating oil stored in the oil pan 15 lubricates the sliding contact portions between the elements constituting the engine 10.

  FIG. 4 conceptually shows the piston 18 to the oil pump 116 by omitting the cylinder block 12, the cylinder head 14, the oil pan 15, the piston pin 28, the small end 24 that is a part of the connecting rod 22, and the like. In FIG. 4, the first oil passage A and the second oil passage B from the oil pump 116 to the first compartment chamber 112 and the second compartment chamber 114 are conceptually depicted. The first oil passage A and the second oil passage B are a crankshaft 36, a crankpin 38, a connecting rod 22, a piston pin from the oil pump 116 to the first and second compartments 112 and 114 of the piston 18. It is configured to include a transfer oil passage partitioned into 28 and the like.

  The connecting rod 22 of the second embodiment includes a first rod oil passage A1 that forms part of the first oil passage A and a second rod oil passage B1 that forms part of the second oil passage B. Is formed. A rod pin hole 118 is positioned and provided in the middle of the first rod oil passage A1 and the second rod oil passage B1. The first rod oil passage A <b> 1 and the second rod oil passage B <b> 1 are formed to extend in parallel, and are both blocked by the rod pin hole 118 on the way.

  The rod pin 120 is inserted into the rod pin hole 118. The rod pin 120 partially defines a first rod pin oil passage A2 that opens the first rod oil passage A1 in the exhaust stroke and a second rod pin oil passage B2 that opens the second rod oil passage B1 in the intake stroke. It is configured accordingly. FIG. 5 conceptually shows a cross-sectional view of the connecting rod 22 in the vicinity of the rod pin 120. The cross-sectional view of FIG. 5 (a) is a cross-sectional view taken along a surface that cuts through the first oil passage A, and the cross-sectional view shown in FIG. is there. The rod pin 120 has a first oil passage groove 122 and a second oil passage groove 124 provided on the outer periphery at locations deviated by a predetermined amount. The first oil passage groove 122 is the first rod oil that is blocked during the exhaust stroke, more specifically, when the piston 18 reaches near the top dead center in the exhaust stroke due to the rotation of the rod pin 120. It has a groove width for opening the path A1. Then, the first rod pin oil passage A2 is partitioned by the first oil passage groove 122 and the rod pin hole 118. Similarly, the second oil passage groove 124 is blocked during the intake stroke, more specifically, when the piston 18 reaches the vicinity of the bottom dead center during the intake stroke due to the rotation of the rod pin 120. It has a groove width for opening the two-rod oil passage B1. Then, the second rod pin oil passage B2 is partitioned by the second oil passage groove 124 and the rod pin hole 118.

  The rod pin 120 is rotated once when the crankshaft 36 rotates twice by the gear drive mechanism 126 that rotates the rod pin 120 in response to the rotation of the crankshaft 36. The gear drive mechanism 126 has a first gear 128, a second gear 134 having a main gear 130 that rotates with the first gear and a sub gear 132 that rotates with the rotation of the main gear 130, and a rotation with the sub gear 132. The third gear 136 is configured. The first gear 128 is coaxial with the crankpin 38 and is fixed around the crankpin 38. The second gear 134 is fixed to the outer surface of the connecting rod 22 between the crank pin 38 and the rod pin 120 so as to be rotatable. The main gear 130 is generally in contact with the outer surface of the connecting rod 22, and the sub gear 132 integrated with the main gear 130 so as to rotate coaxially with the main gear 130 is positioned so as to protrude from the connecting rod 22. That is, the second gear 134 is a two-stage gear. The third gear 136 is coaxial with the rod pin 120, is fixed around the end of the rod pin 120, and rotates with the auxiliary gear 132 of the second gear 134.

  The number of teeth of the sub gear 132 in the second gear 134 is set with respect to the number of teeth of the main gear 130 so that the rod pin 120 rotates once when the crankshaft 36 rotates twice. Therefore, when the first gear 128 is rotated by the rotation of the crankpin 38 of the crankshaft 36, the third gear 136 is rotated so that the rod pin 120 is rotated once when the crankshaft 36 is rotated twice. Therefore, the first rod pin oil passage A2 shown in FIG. 5 opens the first rod oil passage A1 only during an exhaust stroke that is a predetermined time in four cycles. Similarly, the second rod pin oil passage B2 opens the second rod oil passage B1 only during an intake stroke at a predetermined time in four cycles.

  On the other hand, one end of the first rod oil passage A1 and the second rod oil passage B1 of the connecting rod 22 faces the piston pin 28 and opens into the piston pin hole 26. The other end faces the crankpin 38 of the crankshaft 36 and opens into the crankpin hole 34.

  Although not shown, the piston pin 28 is connected to the first rod oil passage A1 and the first compartment 112 of the piston 18 so as to communicate the first rod oil passage A1 with the oil passage A3 of the piston 18. A second piston pin oil passage connecting the pin oil passage, the second rod oil passage B1 and the second compartment 114 of the piston 18 and communicating the second rod oil passage B1 with the oil passage B3 of the piston 18, Is formed. A part of the first piston pin oil passage is partitioned by a first piston pin groove 138 on the outer periphery of the piston pin 28. A part of the second piston pin oil passage is partitioned by the second piston pin groove 140 on the outer periphery of the piston pin 28. The first piston pin oil passage and the second piston pin oil passage are partitioned by the grooves 138 and 140 and the piston pin hole 26. The first piston pin groove 138 and the second piston pin groove 140 are continuous annular grooves around the piston pin 28, respectively.

  The crankpin 38 is formed with a first crankpin oil passage A4 communicating with the first rod oil passage A1 and a second crankpin oil passage B4 communicating with the second rod oil passage B1. A part of the first crankpin oil passage A4 is partitioned by a first crankpin groove 142 on the outer periphery of the crankpin 38. A part of the second crankpin oil passage B <b> 4 is defined by a second crankpin groove 144 on the outer periphery of the crankpin 38. By these grooves 142 and 144 and the crankpin hole 34, the first crankpin oil passage A4 and the second crankpin oil passage B4 are partitioned. Although the first crankpin oil passage A4 and the second crankpin oil passage B4 are not described in detail, they are generally the same in configuration as the first rod pin oil passage A2 and the second rod pin oil passage B2. However, the width and position of the first crankpin groove 142 and the second crankpin groove 144 are different. The first crank pin groove 142 communicates with the first rod oil passage A1 when the piston 18 is rising toward the top dead center, and when the piston 18 is descending toward the bottom dead center. The supply of hydraulic pressure to the first oil passage A is stopped. The second crankpin groove 144 communicates with the second rod oil passage B1 when the piston 18 is lowered toward the bottom dead center, and when the piston 18 is raised toward the top dead center. The supply of hydraulic pressure to the second oil passage B is stopped. That is, when the piston 18 is rising toward the top dead center due to the first crankpin oil passage A4 and the second crankpin oil passage B4, the first oil passage A is changed to the first rod oil passage A1. The second oil passage B is brought into a state in which no hydraulic pressure can be supplied to the second rod oil passage B1. In addition, when the piston 18 is descending toward the bottom dead center, the second oil passage B is in a state where a hydraulic pressure can be supplied to the second rod oil passage B1, and the first oil passage is provided. A is set to a state in which hydraulic pressure cannot be supplied to the first rod oil passage A1 and cannot be supplied. That is, in other words, the crankpin 38 of the crankshaft 36 is provided with supply switching means for switching the supply path of the hydraulic pressure to the first oil passage A and the second oil passage B. The first crankpin oil passage A4 and the second crankpin oil passage B4 are both formed in the bearing portion 117 and the crankshaft 36 from the oil pump 116, and the first oil passage A and the second oil passage B are formed. It communicates with a shaft oil passage AB that forms a part of the shaft. That is, the first oil passage A and the second oil passage B are one in the crankshaft 36.

  The effects of the engine exhaust promotion system of the second embodiment having the above-described configuration will be described below with reference to the drawings. FIG. 4 shown above conceptually represents a state in the exhaust stroke in which a part of the protruding member 88 protrudes from the concave portion 86 at the top of the piston 18. FIG. 5 is a schematic cross-sectional view of the vicinity of the rod pin 120 as shown in FIG. FIG. 6 conceptually shows a state in the intake stroke in which the protruding member 88 is accommodated in the recess 86. In FIG. 7, (a) shows the hydraulic pressure supplied to the first compartment 112 via the first oil passage A, and (b) shows the hydraulic pressure supplied to the second compartment 114 via the second oil passage B. Is schematically shown with respect to the flow of time.

  In the intake stroke (see FIG. 7B), particularly when the piston 18 reaches near the bottom dead center in the intake stroke, the hydraulic pressure is supplied to the second compartment 114 and the hydraulic pressure is not supplied to the first compartment 112. Therefore, when the hydraulic pressure is supplied to the second compartment 114 and the hydraulic pressure is applied, and the force that pushes down the flange portion 96 of the projecting member 88 is applied, the oil in the first compartment 112 flows through the first oil passage A. The oil flows backward to the crankshaft 36 side, leaks from sliding surfaces such as the piston pin 28, the connecting rod 22, and the crankpin 38, and is discharged from the first oil passage A. As a result, as shown in FIG. 6, since the protruding member 88 is accommodated in the recess 86, the volume in the cylinder 16 above the piston 18, for example, the volume of the combustion chamber 20 is maximized. Therefore, more air can be inhaled during the intake stroke.

  Next, in the compression stroke, since the hydraulic pressure is not newly supplied to the first compartment 112 and the second compartment 114, the second compartment 114 is kept in the hydraulic pressure supply state, and the position of the protruding member 88 from the state shown in FIG. Does not change, and a compression ratio like a normal engine can be realized. The same applies to the combustion / expansion stroke.

  Thereafter, in the exhaust stroke (see FIG. 7A), particularly when the piston 18 reaches near the top dead center in the exhaust stroke, the hydraulic pressure is supplied to the first compartment 112 and the hydraulic pressure is supplied to the second compartment 114. Not. Therefore, when the hydraulic pressure is supplied to the first compartment 112 and the hydraulic pressure is applied, and the force that pushes up the protruding member 88 is applied, the oil in the second compartment 114 passes through the second oil passage B on the crankshaft 36 side. Then, it leaks from the sliding surfaces such as the piston pin 28, the connecting rod 22, and the crank pin 38 and is discharged from the second oil passage B. As a result, as shown in FIG. 4, since a part of the projecting member 88 projects from the recess 86, the amount of exhaust gas remaining in the cylinder 16 after the exhaust stroke is reduced as compared with the case where the projecting member 88 is not provided. It will be. That is, the exhaust of the combustion gas from the cylinder 16 is promoted.

  As shown in FIG. 8, when the hydraulic pressure is insufficient such as when the engine is started, the protruding member 88 is moved by the spring 90 as in the first embodiment. In the compression stroke and the combustion / expansion stroke, the protruding member 88 is urged toward the bottom side of the piston 18 by the compression force F <b> 2 and the like, and the protruding member 88 is accommodated in the recess 86. In this way, since the piston top is substantially flat as in the conventional piston 18, a compression ratio as in a normal engine can be realized. On the other hand, in the exhaust stroke, a part of the protruding member 88 protrudes toward the combustion chamber 20 due to the spring force F <b> 1 of the spring 90, so that more exhaust gas is pushed out to the exhaust passage 70 in the exhaust stroke.

  In the second embodiment, the effects described in the first embodiment are also substantially the same. Further, the position of the protruding member 88 can be controlled by the hydraulic pressure except when the hydraulic pressure cannot be sufficiently supplied. The position of the protruding member 88 can be arbitrarily controlled by arbitrarily adjusting the hydraulic pressure supply timing without being limited to the hydraulic pressure supply at the timing shown in FIG.

  In the present invention, various modifications and changes of the second embodiment are allowed. That is, the first compartment or the second compartment is brought into a state in which hydraulic pressure is supplied (hydraulic supply state), and at least a part of the projecting member 88 projects from the recess 86, or the projecting member 88 becomes the recess 86. The first compartment and the second compartment are not limited to the positions and shapes described above, as long as the above-described functions are accommodated. The shape of the protruding member 88 and the shape of the recess 86 may be other than those described above.

  Further, the first rod pin oil passage A2 and the second rod pin oil passage B2 formed at least partially by the rod pin 120 are not limited to the above shapes and positions. All of the first rod pin oil passage A2 and the second rod pin oil passage B2 may be formed inside the rod pin 120. The first rod pin oil passage A2 opens the first rod oil passage A1 in the exhaust stroke, and the second rod pin oil passage B2 opens the second rod oil passage B1 in at least the intake stroke other than the exhaust stroke. good. The gear driving mechanism 126 is not limited to the first to third gears 128, 134, and 136, and has at least one gear. When the crankshaft 36 rotates twice, the rod pin 120 is 1 It only needs to be rotated.

  Further, the first crankpin oil passage A4 and the second crankpin oil passage B4 may not be provided in the crankpin 38. The hydraulic pressure supply path to the first oil path A and the second oil path B is switchable, the first compartment is brought into a hydraulic pressure supply state in the exhaust stroke, and the second compartment is at least an intake stroke other than the exhaust stroke. The hydraulic pressure supply state may be set.

  Next, a third embodiment of the engine exhaust promotion system according to the present invention will be described with reference to the drawings. The engine exhaust promotion system of the third embodiment is substantially the same as that of the second embodiment. In addition to the first oil passage A and the second oil passage B, the third oil passage C is mainly different. Therefore, this difference and the difference in the configuration based on this difference will be described below, and the same as described in the first and second embodiments and the modification thereof will be omitted. In addition, about the same component as the engine system of said 1st and 2nd embodiment, description is abbreviate | omitted using the same code | symbol.

  The third oil passage C is provided in communication with the second compartment 114, and, like the first oil passage A and the second oil passage B, the crankshaft 36, the crankpin 38, the connecting rod 22, the piston pin. It includes 28 transfer oil passages. However, the third oil passage C includes a third rod oil passage C <b> 1 that is not blocked by the rod pin hole 118 and is continuous in the connecting rod 22. Further, the third piston pin oil passage constituting a part of the third oil passage C is partitioned and formed in the piston pin 28 similarly to the first piston pin oil passage and the second piston pin oil passage. Further, unlike the first crankpin oil passage A4 and the second crankpin oil passage B4, the third crankpin oil passage C2 that constitutes a part of the third oil passage C has an annular shape around the crankpin 38. It is formed continuously. The third crankpin oil passage C <b> 2 communicates with the auxiliary shaft oil passage SC in the crankshaft 36. The auxiliary shaft oil passage SC provided in parallel with the shaft oil passage AB is included in the third oil passage C.

  An oil control valve 146 for switching a supply path for switching whether to supply hydraulic pressure to the third oil path C or to supply hydraulic pressure to the first oil path A and the second oil path B is an oil pump 116. (See FIG. 9). Accordingly, in response to the output signal from the ECU 76, the oil control valve 146 is operated and the supply oil passage is switched.

  In the third embodiment, the protruding amount of the protruding member 88 from the recess 86 is increased. On the other hand, the intake / exhaust valves 44 and 46 are operated by a valve mechanism 48 which is a variable valve mechanism. If the amount of overlap between the intake / exhaust valves 44 and 46 exceeds a certain level, the intake / exhaust valves 44 and 46 may collide with the protruding member 88 protruding from the recess 86. Therefore, the following control is performed to avoid interference and collision between the protruding member 88 and the intake / exhaust valves 44 and 46.

  Here, switching control of the oil control valve 146 will be described based on the flowchart of FIG. Note that the control flowchart of FIG. 10 is repeated approximately every 20 ms.

  In step S101, the ECU 76 first searches the data stored in the RAM, detects the overlap amount of the intake / exhaust valves 44, 46, and sets the overlap amount to a predetermined value stored in the ROM in advance. Determine if it has exceeded. This predetermined value is a boundary value at which the intake and exhaust valves 44 and 46 do not interfere with or collide with the protruding member 88.

  If it is determined in step S101 that the overlap amount exceeds the predetermined value and the determination is affirmative, the process proceeds to step S103, and the oil passage on the side where the operation of the protruding member 88 is prohibited is selected. That is, the third oil passage C is selected, and an operation signal is output from the ECU 76 to the oil control valve 146 in order to switch to the supply route to the third oil passage C.

  On the other hand, if it is determined in step S101 that the overlap amount does not exceed the predetermined value and the result is negative, the process proceeds to step S105, and the oil passage on the side that operates the protruding member 88 is selected. That is, an operation signal is output from the ECU 76 to the oil control valve 146 in order to switch to the supply path to the first oil path A and the second oil path B.

  Accordingly, when the overlap amount exceeds or exceeds the predetermined value, only the second compartment 114 is kept in the hydraulic pressure supply state, while the hydraulic pressure is supplied to the first compartment 112. Disappear. For this reason, the protruding member 88 is always housed in the recess 86 at this time. Therefore, the intake / exhaust valves 44 and 46 and the protruding member 88 are prevented from interfering with each other and colliding with each other regardless of the valve timing and the lift amount of the intake / exhaust valves 44 and 46.

  When the overlap amount does not exceed the predetermined value, the projecting member 88 projects in the exhaust stroke as in the second embodiment, and is accommodated in the recess 86 in the other strokes. That is, the effects as described in the second embodiment are achieved.

  As mentioned above, although this invention was demonstrated based on 3rd embodiment, the deformation | transformation and change are accept | permitted in this invention. For example, the predetermined value may be defined from the valve timings of the intake and exhaust valves 44 and 46 when the internal EGR effect is desired. As a result, in an operating state in which the internal EGR is desired to be used, the exhaust gas is retained in the cylinder 16 to some extent. Note that the operating state in which the internal EGR is desired to be used includes a case where it is desired to improve fuel spraying at the time of low temperature start and a case where the vehicle is in a middle load operation.

  Further, in the third embodiment, the valve mechanism 48 using the intake valve 44 and the exhaust valve 46 as electromagnetically driven valves is used so that the valve timing and the lift amount can be freely changed. For example, the valve operating mechanism of the intake / exhaust valves 44 and 46 having cams and camshafts is not excluded. In order to change the overlap amount, any mechanism that makes the phase of the operating angle of at least one of the intake valve 44 and the exhaust valve 46 variable may be used. Such devices include a variable valve timing mechanism and a variable valve timing-lift mechanism. The operating angle phase of the intake valve 44 and the exhaust valve 46 is preferably made variable by the hydraulic pressure controlled by the ECU 76. For example, some cams have a plurality of cams, and by switching the cams, the phase of the operating angle of the intake valve 44 or the exhaust valve 46 is continuously changed. In addition, by providing a variable timing controller on the camshaft rotated by the timing chain and adjusting the hydraulic pressure of the advance chamber in the housing, the phase of the operating angle of the intake valve 44 and the exhaust valve 46 can be adjusted. There are things that change continuously.

  As mentioned above, although this invention was demonstrated based on said 1st to 3rd embodiment and those modification examples, this invention is not limited to them, Various deformation | transformation and a change are included. For example, the present invention includes any combination of the above-described configurations.

It is a conceptual diagram of the engine system in a first embodiment. It is an enlarged view of the piston of FIG. It is a figure for demonstrating the motion of the protrusion member in a piston. FIG. 4 is a conceptual diagram of the first oil passage and the second oil passage from the oil pump to the first compartment and the second compartment in the second embodiment, and an exhaust stroke in which a part of the projecting member projects from the recess. It is a figure which represents notionally in the state. It is sectional drawing of the connecting rod of the rod pin vicinity. It is a figure which represents notionally the state in the intake stroke in which the protrusion member is accommodated in the recessed part. (A) is the graph which represented typically the oil_pressure | hydraulic exerted on a 1st division chamber, (b) is the oil_pressure | hydraulic exerted on a 2nd division chamber with respect to the flow of time. FIG. 7 is a diagram corresponding to FIGS. 4 and 6 when the engine is started. It is a conceptual diagram of a 1st oil path, a 2nd oil path, and a 3rd oil path from an oil pump of a 3rd embodiment to a 1st division chamber and a 2nd division chamber. It is a control flowchart in a third embodiment.

Explanation of symbols

86 Recess 88 Projecting member 90 Spring 112 First compartment 114 Second compartment A First oil passage B Second oil passage C Third oil passage

Claims (7)

A piston with a recess formed at the top;
A projecting member accommodated in the recess so as to project from the top of the piston;
An urging means for urging at least a part of the projecting member to project from the recess at least in an exhaust stroke;
An engine exhaust promotion system characterized by comprising:   2. The engine exhaust acceleration system according to claim 1, wherein the urging means includes a spring that expands and contracts in a cylinder axial direction.   3. The piston according to claim 1, wherein the piston is provided with at least one hole that communicates the compartment formed by the projecting member and the recess and the piston bottom side outer surface. The engine exhaust promotion system described. In the recess, a first compartment chamber in which hydraulic pressure for biasing the protruding member toward the top side of the piston is supplied via the first oil passage, and the protruding member is biased toward the bottom side of the piston. And a second compartment to which hydraulic pressure is supplied via the second oil passage is formed,
The urging means causes the first compartment to be in a hydraulic pressure supply state during an exhaust stroke, causes at least a part of the projecting member to project from the recess, and hydraulically presses the second compartment during at least an intake stroke other than the exhaust stroke. 3. The engine exhaust promotion system according to claim 1, wherein the projecting member is configured to be supplied and accommodated in the recess. 4. The connecting rod includes a first rod oil passage that constitutes part of the first oil passage, a second rod oil passage that constitutes part of the second oil passage, the first rod oil passage, and the first oil passage. A rod pin hole located in the middle of the two rod oil passage is formed,
The rod pin inserted in the rod pin hole has a first rod pin oil passage that opens the first rod oil passage in the exhaust stroke, and a first rod pin that opens the second rod oil passage in at least the intake stroke other than the exhaust stroke. A two-rod pin oil passage is at least partially sectioned;
The engine exhaust acceleration system according to claim 4, wherein the rod pin is rotated once when the crankshaft rotates twice by a gear drive mechanism that rotates the rod pin in response to rotation of the crankshaft. . The crankpin of the crankshaft is provided with a supply switching means for switching a hydraulic pressure supply path to the first oil path and the second oil path,
The supply switching means
When the piston is rising toward the top dead center, the first oil passage is in a state where hydraulic pressure can be supplied, and the second oil passage is in a state where hydraulic pressure cannot be supplied,
2. The hydraulic pressure supply to the second oil passage is enabled and the first oil passage is not to be hydraulically supplied when the piston is descending toward bottom dead center. The engine exhaust promotion system according to 4 or 5. A variable valve mechanism that varies the valve timing or lift amount of at least one of the intake and exhaust valves;
A third oil passage communicating with the second compartment;
An oil control valve for switching a supply path from the hydraulic supply means to the third oil path and the first and second oil paths;
Determination means for determining whether the amount of overlap of the intake and exhaust valves exceeds a predetermined value;
Switching control means for controlling the oil control valve to switch to the supply path to the third oil path when the determination means determines that the overlap amount exceeds the predetermined value;
The engine exhaust promotion system according to any one of claims 4 to 6, further comprising:

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