JP2009036076A - Valve gear for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize an engine speed while shortening engine start time. <P>SOLUTION: This valve gear is provided with: a cam provided on a drive shaft mechanically connected to a crankshaft of an engine 100 and lifting a valve; a valve lift quantity variable mechanism capable of varying lift quantity of a valve, a valve open and close timing variable mechanism capable of varying open and close timing of the valve; a compressed air valve lifted by the cam and opening and closing an opening 105 of the compressed air passage 112; a pressure accumulation means 110 opening the compressed air valve during compression stroke and accumulating air compressed by a piston; a compressed air supply means 110 opening the compressed air valve during expansion stroke and supplying compressed air accumulated by the pressure accumulation means 110 into a cylinder 101; and a compressed air supply quantity-limiting means controlling lift quantity of the compressed air valve by the valve lift quantity variable mechanism according to engine speed and limiting supply quantity of compressed air by the compressed air supply means 110. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine valve operating device.

2. Description of the Related Art Conventionally, there is a device that accumulates gas in a cylinder in a tank via an intake passage by changing the valve timing by an electromagnetic valve / hydraulic drive valve and supplies the gas from the tank to the cylinder when starting the engine. (For example, refer to Patent Document 1).
US Pat. No. 6,223,846

  However, the above-described conventional apparatus controls the amount of gas supplied into the cylinder only by the valve timing. Therefore, the gas amount cannot be controlled when shifting from the gas supply state in which the gas accumulated in the tank at the time of engine start is supplied into the cylinder to the combustion state, particularly when shifting to the minimum air amount state such as idle. For this reason, there has been a problem that the change in the required air amount becomes large and the engine speed is not stable. In addition, it is necessary to set the timing of the valve operating mechanism after determining the cylinder at the time of starting, and there is a problem that it takes time to start.

  The present invention has been made paying attention to such conventional problems, and enables control of the amount of gas when shifting from the gas supply state at the time of engine start to the combustion state and shortens the start time. For the purpose.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention is mechanically linked to a crankshaft of an engine (100), and rotates in conjunction with the rotation of the crankshaft, and a cam provided on the drive shaft (213) for lifting a valve. (220), a valve lift amount variable mechanism (210) that varies the valve lift amount, a valve opening / closing timing variable mechanism (240) that varies the valve opening / closing timing, and the cam (220), A compressed air valve (108) that opens and closes an opening (105) of a compressed air passage (112) communicating with a cylinder (101) of the engine (100), a piston that reciprocates in the cylinder (101), and variable valve opening / closing timing The mechanism (240) controls the opening and closing timing of the compressed air valve (108) to open the compressed air valve (108) during the compression stroke, and the piston is pressurized. Pressure accumulating means for storing the compressed air and the valve opening / closing timing variable mechanism (240) to control the opening / closing timing of the compressed air valve (108) to open the compressed air valve (108) during the expansion stroke and store it by the pressure accumulating means. Compressed air by controlling the lift amount of the compressed air valve (108) by the compressed air supply means for supplying the compressed air into the cylinder (101) and the valve lift amount variable mechanism (210) according to the engine speed. Compressed air supply amount limiting means for limiting the supply amount of compressed air by the supply means.

  According to the present invention, since the variable valve lift amount mechanism that continuously changes the valve lift amount is provided, the compressed air is controlled by controlling the lift amount when shifting from the compressed air supply state at the time of engine start to the combustion state. Can be adjusted. Therefore, the engine speed can be stabilized even if the change in the required air amount increases. Further, since the drive shaft and the crankshaft are mechanically linked and the opening and closing of the compressed air valve is interlocked with the rotation of the crankshaft, combustion can be performed immediately after the cylinder discrimination. Thereby, the starting time can be shortened.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic configuration diagram of an engine 100 according to a first embodiment of the present invention.

  Engine 100 is an in-line four-cylinder engine. Two intake ports 102 and two exhaust ports 103 communicate with the combustion chamber 109 formed in each cylinder 101 of the engine 100. The opening 104 between the combustion chamber 109 and the intake port 102 is opened and closed by an intake valve (not shown), and the opening 107 between the combustion chamber 109 and the exhaust port 103 is opened and closed by an exhaust valve (not shown).

  Further, each combustion chamber 109 of the engine 100 communicates with a branch pipe 112 a of a compressed air supply passage 112 that constitutes a part of the compressed air supply device 110. Below, this compressed air supply apparatus 110 is demonstrated.

  The compressed air supply device 110 includes a compressed air valve (not shown) (see FIG. 2 and the like), a compressed air supply passage 112, a check valve 113, a passage opening / closing valve 114, and a pressure accumulation tank 115. The compressed air supply device 110 stores the compressed air compressed in the combustion chamber 109 during the compression stroke in the pressure accumulation tank 115 and supplies the stored compressed air to the combustion chamber 109 during the expansion stroke according to the vehicle running state. To do.

  The compressed air supply passage 112 branches into four branch pipes 112 a and communicates with the combustion chambers 109. The compressed air supply passage 112 is connected to the air inlet 115 a of the pressure accumulation tank 115 via the check valve 113, and is connected to the air outlet 115 b of the pressure accumulation tank 115 via the passage opening / closing valve 114.

  The accumulator tank 115 stores compressed air.

  The check valve 113 prevents the compressed air from flowing backward from the air inlet 115 a of the pressure accumulation tank 115 to the compressed air supply passage 112.

  The opening / closing of the passage opening / closing valve (solenoid valve, hydraulic valve) 114 is controlled according to the operating state. When the passage opening / closing valve 114 is opened, the supply of the compressed air stored in the pressure accumulation tank 115 is started, and when the passage opening / closing valve 114 is closed, the compressed air Is stopped.

  The compressed air valve (not shown) opens and closes the opening 105 between the branch pipe 112 a and the combustion chamber 109. The compressed air valve opens and closes the opening 105 in conjunction with an intake valve (not shown) that opens and closes the intake port opening 104.

  In addition to this, the engine 100 is provided with a variable valve operating device, thereby changing the lift amount and the lift center angle of the compressed air valve and the intake valve. Hereinafter, the variable valve operating apparatus will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a view showing the variable valve apparatus 200. 3 is a cross-sectional view taken along line III-III in FIG.

  The variable valve apparatus 200 is an apparatus that opens and closes the opening 104 between the combustion chamber 109 and the intake port 102 shown in FIG. The variable valve apparatus 200 is a device that opens and closes the opening 105 between the combustion chamber 109 and the compressed air supply passage 112 shown in FIG.

  As shown in FIG. 2, the variable valve apparatus 200 includes a lift / operation angle variable mechanism 210 that changes the lift / operation angle of the intake valve 106 and the compressed air valve 108, and the phase of the center angle of the lift is advanced or retarded. And a phase varying mechanism 240 for making an angle. In FIG. 2, only a pair of intake valves 106a and 106b, a compressed air valve 108 and related parts corresponding to one cylinder are shown in a simplified manner.

  The variable valve operating apparatus 200 includes a hollow rocker shaft 235 extending in the cylinder row direction, and a drive shaft 213 extending in the cylinder row direction in parallel with the rocker shaft 235.

  The rocker shaft 235 supports the rocker arms 232a and 232b in a swingable manner. The rocker arms 232a and 232b open and close the pair of intake valves 106a and 106b.

  The rocker shaft 235 supports the lost motion rocker arm 300 so as to be swingable. The lost motion rocker arm 300 opens and closes the compressed air valve 108. The configuration of the lost motion rocker arm 300 will be described in detail later. The lost motion rocker arm 300 includes a lost motion mechanism, which eliminates lift transmission from the swing cam 220c to the compressed air valve 108 in accordance with the traveling state of the vehicle, and allows the compressed air valve 108 to remain closed. .

  The variable valve operating apparatus 200 includes a drive shaft 213 extending in the cylinder row direction in parallel with the rocker shaft 235.

  The drive shaft 213 is linked to the crankshaft by a belt or chain (not shown) via a sprocket 242 provided at one end, and rotates around the shaft in conjunction with the crankshaft. The sprocket 242 and the drive shaft 213 are relatively rotated by a phase angle control actuator 241 within a predetermined angle range. Thereby, the lift center angle is advanced or retarded.

  A swing cam 220a, 220b that presses the rocker arms 232a, 232b and a swing cam 220c that presses the lost motion rocker arm 300 are rotatably attached to the drive shaft 213 for each cylinder. .

  The swing cams 220a and 220b are fixed to each other in the same phase by the cylinder 230. Similarly, the swing cams 220 a and 220 c are also fixed to each other in the same phase by the cylinder 231. When the swing cams 220a to 220c swing (up and down) within a predetermined rotation range around the drive shaft 213, the rocker arms 232a and 232b and the lost motion rocker arm 300 positioned below the swing cams 220a to 220c are pressed, respectively. 106a, 106b and the compressed air valve 108 are lifted downward.

  The drive shaft 213 fixedly supports the cylindrical drive cam 215 at a position away from the swing cam 220b by a predetermined distance on the right side in the axial direction in the drawing. As shown in FIG. 3, the center P4 of the drive cam 215 is offset from the axis P3 of the drive shaft 213 by a predetermined amount. A first link 225 is rotatably fitted on the outer periphery of the drive cam 215.

  Above the drive shaft 213, a control shaft 216 extending in the cylinder row direction parallel to the drive shaft 213 is rotatably supported.

  As shown in FIG. 3, the control shaft 216 fixedly supports a cylindrical control cam 217. The center P1 of the control cam 217 is offset from the axis P2 of the control shaft 216 by a predetermined amount. A link arm 218 is rotatably fitted on the outer periphery of the control cam 217. The link arm 218 swings about the axis P1 of the control cam 217 as a fulcrum.

  The link arm 218 and the first link 225 are connected by a connecting pin 221 that passes through both. Further, the link arm 218 and the second link 226 are connected by a connecting pin 228. Further, the second link 226 and the swing cam 220a are connected by a connecting pin 229. As described above, the drive cam 215 and the link arm 218 are linked by the first link 225, and the link arm 218 and the swing cam 220 are linked by the second link 226. A snap ring that restricts the axial movement of the first link 225 and the second link 226 is provided at one end of each pin 221, 228, 229.

  When the drive shaft 213 rotates in conjunction with the crankshaft of the engine by the variable valve apparatus 200 configured as described above, the link arm 218 is connected to the center P1 of the control cam 217 via the drive cam 215 and the first link 225. And the swing cam 220a swings within a predetermined angle range via the second link 226.

  At this time, the swing cams 220a and 220b are fixed to each other by the cylinder 230 in the same phase. Therefore, the rocking cams 220a and 220b push down the rocker arms 232a and 232b in synchronization with each other and drive the intake valves 106 and 106b to open and close.

  Similarly, the swing cams 220a and 220c are fixed to each other in the same phase by the cylinder 231. The swing cam 220c pushes down the lost motion rocker arm 300 to drive the compressed air valve 108 to open and close. However, the swing cam 220c is attached to the drive shaft 213 so that the cam lobe faces in a direction approximately 180 degrees opposite to the cam lobe direction of the swing cam 220a. Therefore, there is a phase difference of about 180 degrees between the opening timing of the compressed air valve 108 and the opening timing of the intake valve 106.

  The control shaft 216 is controlled to rotate within a predetermined rotation angle range by a lift amount control actuator 251 provided at one end. When the control shaft 216 rotates, the center P1 of the control cam 217 serving as the swing fulcrum of the link arm 218 is also rotationally displaced, and the support position of the link arm 218 is changed with respect to the engine body. As a result, the valve lift characteristics of the intake valves 106a and 106b and the compressed air valve 108 of all the cylinders to which the control shaft 216 is applied, specifically, both the lift amount and the operating angle are continuously changed and controlled. . Here, as described above, the swing cam 220c is attached to the drive shaft 213 so that its cam lobe is directed in a direction approximately 180 degrees opposite to the cam lobe direction of the swing cam 220a. For this reason, the lift amount of the compressed air valve 108 decreases as the lift amount of the intake valves 106a and 106b increases.

  Further, the phase angle control actuator 241 provided at one end of the drive shaft 213 relatively rotates the sprocket 242 and the drive shaft 213 within a predetermined angle range. As a result, the lift center angle is advanced or retarded.

  The phase angle control actuator 241 and the lift amount control actuator 251 are controlled by a controller (not shown) according to the operating state.

  Next, the lost motion rocker arm 300 will be described with reference to FIG.

  FIG. 4A is a plan view of the lost motion rocker arm 300. FIG. 4B is a cross-sectional view taken along line BB in FIG. 4A and corresponds to the cross-sectional view in FIG.

  The lost motion rocker arm 300 includes a main rocker arm 301, a sub rocker arm 310, and a coupling mechanism 330 that couples the main rocker arm 301 and the sub rocker arm 310.

  The main rocker arm 301 is swingably supported by a hollow rocker shaft 235 inserted through an insertion hole 301c formed in the base end portion 301a. Then, the distal end of the arm portion 301 b extending from the base end portion 301 a comes into contact with the stem end of the compressed air valve 108.

  A recess for accommodating the sub rocker arm 310 is formed on the upper surface of the main rocker arm 301, and a bearing hole 301d through which the sub rocker shaft 311 for supporting the sub rocker arm 310 is inserted is formed in a side wall of the recess.

  The sub rocker arm 310 is accommodated in a recess formed on the upper surface of the main rocker arm 301. The sub rocker arm 310 is swingably supported by a sub rocker shaft 311 inserted through an insertion hole 310c formed in the base end portion 310a. A slipper surface 310f that is in sliding contact with the swing cam 220c is formed on the top surface of the tip end portion 310b of the sub rocker arm 310.

  As shown in FIG. 4B, the sub rocker arm 310 is biased upward by a lost motion spring 320 provided on the upper surface 301e of the base end portion 301a of the main rocker arm 301 via the retainer 321.

  The coupling mechanism 330 couples the main rocker arm 301 and the sub rocker arm 310 according to the traveling state of the vehicle, or releases the coupling. The coupling mechanism 330 includes a coupling lever 331 and a hydraulic plunger 332.

  The coupling lever 331 is rotatably supported by a connecting pin 333 supported at both ends by the main rocker arm 301. And the front-end | tip part 331a of a coupling lever couple | bonds with the step part 310g formed in the lower surface of the front-end | tip part 310b of the sub rocker arm 310. FIG. The distal end 331a of the coupling lever 331 is always urged in the non-coupling direction (right direction in the figure) by a return spring (not shown).

  The hydraulic plunger 332 biases the distal end portion 331a of the coupling lever 331 in the coupling direction (left direction in the figure) by the hydraulic pressure of the hydraulic pressure supply passage 235a in the rocker shaft 235 supplied through the oil hole 334.

  Next, the operation of the lost motion rocker arm 300 will be described.

  FIG. 5 is a diagram for explaining the operation of the lost motion rocker arm 300. FIGS. 5A and 5B are views showing the operation in a state where the connection between the main rocker arm 301 and the sub rocker arm 310 is released. FIG. 5C is a diagram showing an operation in a state where the main rocker arm 301 and the sub rocker arm 310 are coupled.

  As shown in FIGS. 5A and 5B, when no hydraulic pressure is applied to the hydraulic plunger 332, the coupling lever 331 is rotated in the non-coupling direction by the urging force of the return spring. Therefore, the front end 331 a of the coupling lever 331 is separated from the stepped portion 310 g of the sub rocker arm 310. As a result, the connection between the main rocker arm 301 and the sub rocker arm 310 is released.

  Then, by the spring force of the lost motion spring 320, the swing of the swing cam 220c is only converted to the swing of the sub rocker arm 310 with the sub rocker shaft 311 as a fulcrum, and the main rocker arm 301 does not swing. Therefore, the compressed air valve 108 remains closed.

  On the other hand, as shown in FIG. 5C, when hydraulic pressure is applied to the hydraulic plunger 332, the coupling lever 331 rotates in the coupling direction by overcoming the urging force of the return spring. Therefore, the distal end portion 331 a of the coupling lever 331 is coupled to the step portion 310 g of the sub rocker arm 310. As a result, the main rocker arm 301 and the sub rocker arm 310 are coupled.

  Then, the swing of the swing cam 220c is converted to the swing of the main rocker arm 301 about the rocker shaft 235 via the sub rocker arm 310. Thereby, the compressed air valve 108 is driven to open and close in accordance with the swing of the swing cam 220c.

  Next, an opening / closing operation mode of the compressed air valve 108 according to the vehicle running state will be described with reference to FIGS.

  6 and 7 are diagrams showing the opening / closing timings of the intake valve 106, the exhaust valve, and the compressed air valve 108 in each cylinder. FIG. 6 is a diagram showing the opening / closing timing of each valve when the vehicle is decelerated and stopped. FIG. 7 is a diagram showing the opening / closing timing of each valve when the vehicle is started. Note that the arrows in each figure indicate the time when the intake valve 106, the exhaust valve, and the compressed air valve 108 are open.

  First, with reference to FIG. 6, the opening / closing timing of each valve at the time of vehicle deceleration and stop will be described.

  When the vehicle decelerates and stops, the compressed air valve 108 opens and closes according to the lift of the swing cam 220c in a state where the main rocker arm 301 and the sub rocker arm 310 of the lost motion rocker arm 300 are coupled (hereinafter referred to as “coupled state”). State On the other hand, the passage opening / closing valve 114 is closed. Then, as shown in FIG. 6, the valve timing is controlled by the variable valve apparatus 200 so that the compressed air valve 108 opens in the latter half of the compression stroke.

  Thus, when the vehicle is decelerated and stopped, the compressed air valve 108 is opened in the latter half of the compression stroke, while the passage opening / closing valve 114 is always closed. As a result, the air compressed in the combustion chamber 109 during the compression stroke is sent to the pressure accumulation tank 115.

  Next, with reference to FIG. 7, the opening / closing timing of each valve at the time of engine start will be described.

  When the engine is started, the lost motion rocker arm 300 is connected and the compressed air valve 108 is opened and closed according to the lift of the swing cam 220c. The passage opening / closing valve 114 is also opened. Then, as shown in FIG. 7, the valve timing is controlled by the variable valve apparatus 200 so that the compressed air valve 108 opens in the expansion stroke. At this time, the opening timing of the exhaust valve and the closing timing of the compressed air valve 108 are controlled to be substantially the same.

  Thus, when the engine is started, the compressed air valve 108 is opened during the expansion stroke with the passage opening / closing valve 114 being opened. Thereby, the compressed air from the pressure accumulation tank 115 can be supplied to the combustion chamber 109 to push down the piston, and the engine speed can be quickly increased. At this time, the variable valve device 200 ensures that the opening timing of the exhaust valve and the closing timing of the compressed air valve 108 are substantially the same, so that the compressed air supplied to the combustion chamber 109 is reliably supplied to the piston. Can be used for work to push down.

  During steady vehicle travel, the compressed air valve 108 is always closed in a state in which the main rocker arm 301 and the sub rocker arm 310 of the lost motion rocker arm 300 are disconnected (hereinafter referred to as “non-coupled state”). The passage opening / closing valve 114 is also closed. That is, during steady vehicle travel, both the compressed air valve 108 and the passage opening / closing valve 114 are closed.

  FIG. 8 is a time chart for explaining the operation of the intake valve 106 and the compressed air valve 108 during vehicle deceleration.

  When the vehicle shifts from the steady running state to the decelerating running state at time t1 (FIG. 8A), the lost motion rocker arm 300 is connected to store the compressed air in the combustion chamber 109 during the compression stroke in the pressure accumulating tank 115. (FIG. 8D), the compressed air valve 108 is driven to open and close. At this time, the lift center angle of the intake valve 106 is retarded (FIG. 8B), and the opening / closing timing of the compressed air valve 108 is set to the latter half of the compression stroke (FIG. 8C). As described above, since there is a phase difference of about 180 degrees between the opening timing of the compressed air valve 108 and the opening timing IVO of the intake valve 106, the compression can be achieved by controlling the IVO near the exhaust top dead center. The opening / closing timing of the air valve 108 is set to the latter half of the compression stroke. The passage opening / closing valve 114 remains closed (FIG. 8E).

  As described above, when the vehicle is decelerated, the compressed air can be stored in the pressure accumulating tank 115 by opening the compressed air valve 108 in the latter half of the compression stroke while keeping the passage opening / closing valve 114 closed.

  FIG. 9 is a time chart for explaining operations of the intake valve 106 and the compressed air valve 108 when the engine is stopped.

  When the engine is stopped at time t1, the lift center angle of the intake valve 106 is retarded (FIG. 9B), and the opening / closing timing of the compressed air valve 108 is set to be the expansion stroke (FIG. 9 ( C)). At the same time, the lift amount of the intake valve 106 is set to a small lift (FIG. 9B), and the lift amount of the compressed air valve 108 is set to a large lift (FIG. 9C). Further, the lost motion rocker arm 300 is set in a coupled state (FIG. 9D).

  In this way, when the engine is stopped, in preparation for the next engine start, the opening / closing timing of the compressed air valve 108 is set in advance to be in the expansion stroke, and the lost motion rocker arm 300 is set in the coupled state. Thereby, the compressed air stored in the pressure accumulation tank 115 can be quickly supplied to the combustion chamber 109 at the next engine start.

  FIG. 10 is a time chart for explaining the operation of the intake valve 106 and the compressed air valve 108 when the engine is started.

  When the engine is started at time t1, the passage opening / closing valve 114 is opened (FIG. 10E). The lost motion rocker arm 300 is in a coupled state (FIG. 10D). Thereby, the compressed air stored in the pressure accumulating tank 115 is supplied to the combustion chamber 109 according to the opening / closing of the compressed air valve 108. The piston is pushed down by this compressed air, and the engine speed increases.

  At this time, as the engine speed increases, the lift amount of the intake valve 106 is increased (FIG. 10B), the lift amount of the compressed air valve 108 is decreased (FIG. 10C), and the combustion chamber 109 is increased. Reduce the amount of compressed air supplied to Thereby, even if it becomes an appropriate engine rotation speed and ignition combustion is performed and it will be in an idle state, an engine rotation speed can be stabilized.

  Further, since the engine can be started by increasing the engine rotation speed with the pressure of compressed air when the engine is started, idling can be stopped and idle fuel can be saved.

  According to the present embodiment described above, the variable valve lift amount mechanism 210 that continuously changes the valve lift amount is provided. Therefore, when the engine is started from the compressed air supply state to the combustion state, the lift amount is reduced. The supply amount of compressed air can be adjusted by control. Therefore, the engine speed can be stabilized even if the change in the required air amount increases.

  Further, since the drive shaft 213 and the crankshaft are mechanically linked and the opening / closing of the compressed air valve 108 is linked with the rotation of the crankshaft, combustion can be performed immediately after the cylinder discrimination. Thereby, the starting time can be shortened.

  Further, the compressed air is stored in the pressure accumulating tank 115 when the vehicle is decelerated, and the air stored in the pressure accumulating tank 115 is supplied to the combustion chamber 109 when the engine is started. As a result, when the engine is started, the engine speed can be increased by the pressure of the compressed air to start the engine, so that idling can be stopped and idle fuel can be saved.

  Further, since the opening timing of the exhaust valve and the closing timing of the compressed air valve 108 are made substantially the same by the variable valve operating device 200, the compressed air supplied to the combustion chamber 109 can reliably push down the piston. Can be used for

  Further, the swing cams 220 a to 220 c that lift the compressed air valve 108 and the swing cams 220 a and 220 b that lift the intake valve 106 have a phase difference, and the swing cams 220 a to 220 c are integrally formed on the drive shaft 213. Thus, by controlling the lift amount or the central angle of the intake valve, the compressed air valve 108 can be controlled at the same time, so that a simple system configuration can be achieved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 11 is a diagram showing the engine 100 including the variable compression ratio mechanism 400 that changes the engine compression ratio by changing the piston stroke.

  The second embodiment of the present invention is different from the first embodiment in that the compression ratio is set to a high compression ratio when the vehicle is decelerated and a large amount of compressed air can be stored in the pressure accumulation tank 115. Hereinafter, the difference will be described.

  The compression ratio variable mechanism 400 connects the piston 422 and the crankshaft 421 with two links (an upper link (first link) 411 and a lower link (second link) 412), and a control link (third link) 413. To control the lower link 412 to change the compression ratio.

  The upper link 411 has an upper end connected to the piston 422 via a piston pin 424 and a lower end connected to one end of the lower link 412 via a connection pin 425. The piston 422 is slidably fitted to a cylinder liner 429 fitted to the cylinder block 423, receives combustion pressure, and reciprocates in the cylinder 101.

  The lower link 412 has one end connected to the upper link 411 via the connection pin 425 and the other end connected to the control link 413 via the connection pin 426. Further, the lower link 412 inserts the crank pin 421b of the crankshaft 421 into a substantially central connecting hole, and swings around the crank pin 421b as a central axis. The lower link 412 can be divided into left and right members. The crankshaft 421 includes a plurality of journals 421a and a crankpin 421b. The journal 421a is rotatably supported by the cylinder block 423 and the ladder frame 128. The crank pin 421b is eccentric from the journal 421a by a predetermined amount, and a lower link 412 is swingably connected thereto.

  The control link 413 is connected to the lower link 412 via a connecting pin 426. The control link 413 connects the other end to the control shaft 414 via a connecting pin 427. The control link 413 swings around the connecting pin 427. A gear is formed on the control shaft 414, and the gear meshes with a pinion 132 provided on the rotation shaft 133 of the compression ratio control actuator 431. The control shaft 414 is rotated by the compression ratio control actuator 431, and the connecting pin 427 moves.

  FIG. 12 is a diagram for explaining a compression ratio changing method by the variable compression ratio mechanism 400.

  The compression ratio variable mechanism 400 controls the compression ratio control actuator 431 by the controller to rotate the control shaft 414 and change the position of the connecting pin 427 to change the compression ratio. For example, as shown in FIGS. 12 (A) and 12 (C), when the connecting pin 427 is set to the position P, the top dead center position (TDC) is increased and the compression ratio is increased.

  Then, as shown in FIGS. 12B and 12C, when the connecting pin 427 is set to the position Q, the control link 413 is pushed upward, and the position of the connecting pin 426 is raised. As a result, the lower link 412 rotates counterclockwise about the crank pin 421b, the connecting pin 425 is lowered, and the position of the piston 422 at the piston top dead center is lowered. Therefore, the compression ratio becomes a low compression ratio.

  According to the present embodiment described above, since the variable compression ratio mechanism 400 is provided, it is possible to control the compression pressure when controlling the compression ratio and sending the compressed air to the pressure accumulation tank 115 during vehicle deceleration. Therefore, for example, if the compression ratio is set to a high compression ratio during vehicle deceleration, a large amount of compressed air can be stored in the pressure accumulation tank 115. Thereby, the pressure storage tank 115 can be reduced in size.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

It is a schematic block diagram of the engine by 1st Embodiment. It is a figure which shows a variable valve apparatus. It is sectional drawing which follows the III-III line of FIG. It is a figure explaining a lost motion rocker arm. It is a figure explaining operation | movement of a lost motion rocker arm. It is a figure which shows the opening / closing timing of each valve | bulb at the time of vehicle deceleration and a stop. It is a figure which shows the opening / closing timing of each valve | bulb at the time of vehicle starting. It is a time chart explaining operation | movement of the intake valve and compressed air valve at the time of vehicle deceleration. It is a time chart explaining operation | movement of an intake valve and a compressed air valve at the time of an engine stop. It is a time chart explaining operation | movement of the intake valve and compressed air valve at the time of engine starting. It is a figure which shows the engine provided with the compression ratio variable mechanism which changes an engine compression ratio by changing a piston stroke. It is a figure explaining the compression ratio change method by a compression ratio variable mechanism.

Explanation of symbols

100 Engine 101 Cylinder 105 Compressed air passage opening 106 Intake valve 108 Compressed air valve 112 Compressed air passage (compressed air introduction passage) (Compressed air discharge passage)
114 Passage opening / closing valve 115 Accumulation tank 210 Lift / operating angle variable mechanism (lift amount variable mechanism)
213 Drive shaft 218 Link arm (multiple links)
220a Oscillating cam (Oscillating cam that lifts the intake valve)
220b Oscillating cam (Oscillating cam that lifts the intake valve)
220c Oscillating cam (Oscillating cam that lifts the compressed air valve)
225 First link (multiple links)
226 Second link (multiple links)
240 Phase variable mechanism (Valve open / close timing variable mechanism)
300 Lost motion rocker arm (lost motion mechanism)
301 Main rocker arm 310 Sub rocker arm 330 Coupling mechanism 400 Compression ratio variable mechanism

Claims (10)

A drive shaft that is mechanically linked to the crankshaft of the engine and rotates in conjunction with the rotation of the crankshaft;
A cam provided on the drive shaft for lifting the valve;
A variable valve lift mechanism that makes the valve lift variable;
A valve opening / closing timing variable mechanism that makes the valve opening / closing timing variable;
A compressed air valve which is lifted by the cam and opens and closes an opening of a compressed air passage communicating with the cylinder of the engine;
A piston that reciprocates in the cylinder;
A pressure accumulating means for controlling the opening / closing timing of the compressed air valve by the valve opening / closing timing variable mechanism, opening the compressed air valve during a compression stroke, and storing the compressed air compressed by the piston;
Compressed air supply means for controlling the opening / closing timing of the compressed air valve by the valve opening / closing timing variable mechanism, opening the compressed air valve during the expansion stroke, and supplying the compressed air stored by the pressure accumulating means into the cylinder; ,
Compressed air supply amount limiting means for controlling the lift amount of the compressed air valve by the valve lift amount variable mechanism according to the engine rotation speed and limiting the supply amount of compressed air by the compressed air supply means;
A valve operating apparatus for an engine characterized by comprising: The pressure accumulating means is
A pressure accumulator for storing compressed air;
A compressed air introduction passage connecting the inlet of the pressure accumulator and the compressed air passage;
2. The engine valve operating device according to claim 1, wherein when the vehicle is decelerated, the compressed air valve is opened during a compression stroke to store compressed air in the pressure accumulator. A variable compression ratio mechanism for changing the engine compression ratio of the engine;
The valve operating apparatus for an engine according to claim 2, wherein the pressure accumulating means sets the engine compression ratio to a high compression ratio when the vehicle is decelerated. The compressed air supply means includes
A compressed air discharge passage connecting the outlet of the pressure accumulator and the compressed air passage;
A passage opening / closing valve provided in the compressed air discharge passage for opening and closing the compressed air discharge passage;
4. The compressed air stored in the pressure accumulator is supplied to the cylinder by opening the passage opening / closing valve and opening the compressed air valve during an expansion stroke when the vehicle is started. 5. Engine valve gear. 5. The valve operating apparatus for an engine according to claim 4, wherein the compressed air supply means makes the closed timing of the compressed air valve at the time of starting the vehicle substantially the same as the open timing of the exhaust valve. A lost motion mechanism for stopping the valve lift of the compressed air valve;
The valve operating device for an engine according to any one of claims 1 to 5, wherein the cam lifts the compressed air valve via the lost motion mechanism. The lost motion mechanism is
A main rocker arm with a proximal end rotatably supported and a distal end abutting the compressed air valve;
A sub rocker arm whose base end is rotatably supported by the main rocker arm and whose upper surface is in contact with the cam;
A coupling mechanism for coupling the main rocker arm and the sub rocker arm;
By connecting the main rocker arm and the sub rocker arm, the lift of the cam is transmitted to the main rocker arm via the sub rocker arm to lift the compressed air valve,
The engine according to claim 6, wherein the lift of the compressed air valve is stopped without transmitting the lift of the cam to the main rocker arm by releasing the connection between the main rocker arm and the sub rocker arm. Valve gear. 8. The drive shaft according to claim 1, further comprising a cam having a phase difference from a cam that lifts an intake valve and lifts the compressed air valve, in addition to a cam that lifts the compressed air valve. The valve operating apparatus of the engine as described in any one of these. 9. The valve gear for an engine according to claim 8, wherein the drive shaft includes one cam for lifting the compressed air valve and two cams for lifting the intake valve for each cylinder. The cam is a swing cam that is rotatably supported by the drive shaft and lifts the valve by a swing motion;
The variable valve lift amount mechanism converts the rotational motion of the drive shaft into the swing motion via a plurality of links, and continuously changes the valve lift amount by changing the phase of the swing cam. Mechanism to change,
The valve opening / closing timing variable mechanism is a mechanism that changes the valve opening / closing timing by changing a phase angle of the drive shaft with respect to the crankshaft. The valve operating device for an engine according to 1.

Images