JP4604358B2 - Internal combustion engine and control system thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine and a control system thereof.
[0002]
[Prior art]
The ratio of the cylinder volume, which is the volume on the combustion chamber side when the piston is at bottom dead center, and the gap volume, which is the volume on the combustion chamber side when the piston is at top dead center, is called the compression ratio ε. Yes. On the other hand, the ratio between the effective cylinder volume, which is the maximum value of the working gas volume, and the effective gap volume, which is the minimum value of the working gas volume, is called the effective compression ratio ε ′. Yes.
[0003]
A multi-link type piston stroke variable mechanism that variably controls the compression ratio ε by changing the piston top dead center position has been filed by the present applicant prior to the present application.
[0004]
In a so-called variable compression ratio engine employing such a piston stroke variable mechanism, the compression ratio ε is basically used on the higher side than the conventional fixed compression ratio engine.
[0005]
In the case of a variable compression ratio engine, there is a concept of improving the specific output in combination with a supercharger. In this case, as shown in FIG. 14, the compression ratio ε is fixed to the fixed compression ratio engine during supercharging. Reduce relative to compression ratio.
[0006]
[Problems to be solved by the invention]
However, when the compression ratio ε determined by the piston stroke is increased, the S / V ratio (combustion chamber surface area / combustion chamber volume) of the combustion chamber at the top dead center position increases as shown in FIG. There is a problem that the cooling loss at the time increases.
[0007]
Further, when the S / V ratio of the combustion chamber at the top dead center position is large and the effective compression ratio ε ′ is not high, flame propagation in the combustion chamber becomes slow, and the compression ratio ε depends on the engine operating conditions. Therefore, there is a problem that the effect of improving the fuel efficiency obtained by the control tends to be reduced.
[0008]
On the other hand, as shown in FIG. 15, the S / V ratio of the combustion chamber at the top dead center position decreases when the valve clamping angle of the intake / exhaust valve is decreased. In addition, the valve diameter of the intake / exhaust valve becomes smaller, the intake amount at high speed decreases, the output decreases, and the distance between the camshafts that drive the intake / exhaust valve becomes smaller. There is a problem that trade-offs are inevitable, such as difficulty in chain layout.
[0009]
Accordingly, an object of the present invention is to provide an engine configuration that does not increase the S / V ratio of the combustion chamber at the top dead center position and does not cause a tradeoff such as deterioration of output performance.
[0010]
[Means for Solving the Problems]
  Accordingly, the invention according to claim 1 is directed to the intake valve and the exhaust valve by swinging the swing cam that is rotatably and swingably mounted on the drive shaft.Both sidesIn an internal combustion engine that lifts the shaft,SuckAir valve and exhaust valveBoth sidesThe center line of the valve stem is, BurningIt is characterized by being located on the axis line passing through the center of the firing chamber. As a result, the valve clamping angle can be reduced without changing the layout of the drive shaft and the swing cam, and the S / V ratio at the top dead center position is relatively reduced.
[0011]
  Also,The swing cam is a component of a variable lift / operating angle mechanism that can simultaneously and continuously expand and contract the lift / operating angle of the intake valve or the exhaust valve..
[0012]
in frontThe lift / operating angle variable mechanism includes an eccentric cam that is rotationally driven by the drive shaft, a link arm that is fitted to the outer periphery of the eccentric cam so as to be relatively rotatable, and an eccentric cam that is provided in parallel with the drive shaft. A rotatable control shaft provided with a portion, a rocker arm that is rotatably mounted on an eccentric cam portion of the control shaft and is rocked by the link arm, and is rotatably supported by the drive shaft, And an oscillating cam that presses a valve lifter of the intake valve or the exhaust valve by oscillating along with the rocker arm and oscillating with the rocker arm, and an eccentric cam portion of the control shaft The lift / operating angle of the intake valve or the exhaust valve is increased or decreased at the same time by changing the rotation position of the intake valve.The
[0013]
  Claim2The invention described in claim1The piston stroke variable mechanism for changing the piston top dead center position and means for detecting the rotational speed and load of the internal combustion engine, and the piston stroke according to the rotational speed and load of the internal combustion engine. The variable mechanism and the lift / operating angle variable mechanism are controlled. The compression ratio ε can be variably controlled by changing the piston top dead center position.
[0014]
  Claim3The invention described in claim2In the invention described in the above, when the load of the internal combustion engine is small, the piston stroke variable mechanism is controlled so that the compression ratio ε of the internal combustion engine becomes high, and the closing timing of the intake valve is kept away from the bottom dead center. The effective compression ratio ε ′ of the internal combustion engine is reduced. While maintaining good combustion by increasing the compression ratio ε, reducing the effective compression ratio ε ′ enables a reduction in pump loss and suppresses an increase in the S / V ratio due to an increase in the compression ratio ε. The
[0015]
  Claim4The invention described in claim2Or3In the invention described in the above, the piston stroke variable mechanism is substantially the same as an upper link connected at one end to a piston pin of a piston, a lower link connected to the upper link and a crank pin of a crankshaft, and the crankshaft. A control shaft extending in parallel and one end of the control shaft are swingably connected to the control shaft, the other end is connected to the lower link, and the swing center with respect to the control shaft is relative to the rotation center of the control shaft. And an eccentric control link, and the piston top dead center position is changed by rotating the control shaft.
[0016]
  Claim5The invention described in claim2~4In any one of the inventions, the piston stroke variable mechanism is characterized in that a stroke characteristic related to crank rotation of the piston is substantially simple vibration. Since the piston stroke variable mechanism is a multi-link mechanism having an upper link, a lower link, and a control link, the stroke characteristics related to the crank rotation of the piston can be made to be substantially simple vibration.
[0017]
  Claim6The invention described in claim2~5In any one of the inventions, when the rotational speed of the internal combustion engine is high, the lift / operating angle of the intake valve and / or the exhaust valve is controlled to be enlarged. The valve diameter of the intake / exhaust valve relatively decreases as the valve squeezed angle decreases. However, when the load on the internal combustion engine is large, the output decreases by increasing the lift and operating angle according to the amount of decrease in the valve diameter. Can be supplemented.
[0018]
  Claim7The invention described in claim2~6In the invention according to any one of the above, any one of intake negative pressure, intake air amount, throttle opening, and fuel injection amount is used as the load detecting means of the internal combustion engine.
[0019]
  Claim8The invention described in claim1~7In the invention described in any one of the above, with respect to the center of the valve lifter, the swing center of the swing cam is disposed on the outside with respect to the axis passing through the center of the combustion chamber, and the intake valve and / or the exhaust valve. The valve lifter is driven so that the contact position of the swing cam with respect to the valve lifter is furthest away from the axis passing through the center of the combustion chamber when the valve lifts to the maximum.
[0020]
  Claim9The invention described in claim 18In any one of the inventions, a phase variable mechanism for delaying the phase of the lift center angle of the intake valve is provided.
[0021]
【The invention's effect】
According to the present invention, the angle between the intake and exhaust valves can be reduced without changing the layout of the drive shaft and the swing cam. In addition, by reducing the valve sandwich angle of the intake / exhaust valve, the S / V ratio at the top dead center position that increases by increasing the compression ratio ε can be relatively reduced, and the cooling loss can be reduced. .
[0022]
  And claims2As described above, even when the compression ratio ε is variably controlled by the piston stroke variable mechanism according to the operating conditions, the S / V ratio at the top dead center position that increases by increasing the compression ratio ε is relatively small. The cooling loss can be reduced without deteriorating the output performance.
[0023]
  Claim3Then, while maintaining good combustion by increasing the compression ratio ε, the pump loss can be reduced by lowering the effective compression ratio ε ′, and the S at the top dead center position due to the increase of the compression ratio ε. Increase in the / V ratio is suppressed. That is, the cooling loss can be reduced without deteriorating the output performance.
[0024]
  Claim5By doing so, the secondary vibration can be reduced.
[0025]
  Claims6Then, under a condition where the load on the internal combustion engine is large, the decrease in output can be compensated for by increasing the lift / operating angle in accordance with the valve diameter of the intake valve, which is decreased by reducing the valve sandwich angle.
[0026]
  And claims8By doing so, the setting range of the valve clamping angle of the intake / exhaust valve can be increased.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0028]
FIG. 1 is a configuration explanatory view showing the configuration of an intake valve side variable valve mechanism of an internal combustion engine. This variable valve mechanism includes a lift / working angle variable mechanism 1 that changes a lift / working angle of an intake valve 4 and The phase variable mechanism 2 for advancing or retarding the phase of the center angle of the lift (the phase with respect to the crankshaft (not shown)) is combined.
[0029]
FIG. 2 shows only the lift / operating angle variable mechanism 1, and the lift / operating angle variable mechanism 1 will be described with reference to FIGS. 1 and 2.
[0030]
The variable lift / operating angle mechanism 1 has a hollow shape rotatably supported by an intake valve slidably provided on a cylinder head 3 via a valve guide (not shown) and a cam bracket 5 above the cylinder head 3. A drive shaft 6, an eccentric cam 7 fixed to the drive shaft 6 by press-fitting or the like, and an upper position of the drive shaft 6 that is rotatably supported by the same cam bracket 5 and arranged in parallel with the drive shaft 6. The control shaft 8, a rocker arm 10 that is swingably supported by the eccentric cam portion 9 of the control shaft 8, and a swing that abuts against the upper end portion of each intake valve, that is, the valve lifter 11 disposed at the upper end portion of the valve stem 4. A moving cam 12. The eccentric cam 7 and the rocker arm 10 are linked by a link arm 13, and the rocker arm 10 and the swing cam 12 are linked by a link member 14.
[0031]
As will be described later, the drive shaft 6 is driven by a crankshaft of an engine via a timing chain or a timing belt.
[0032]
The eccentric cam 7 has a circular outer peripheral surface, the center of the outer peripheral surface is offset by a predetermined amount from the axis of the drive shaft 6, and the annular portion 13a of the link arm 13 can be rotated on the outer peripheral surface. It is mated.
[0033]
The rocker arm 10 is supported by the eccentric cam portion 9 at its substantially central portion, and the extension portion 13b of the link arm 13 is linked to one end portion thereof, and the upper end portion of the link member 14 is linked to the other end portion thereof. is doing. The eccentric cam portion 9 is eccentric from the axis of the control shaft 8, and accordingly, the rocking center of the rocker arm 10 changes according to the angular position of the control shaft 8.
[0034]
The swing cam 12 is fitted to the outer periphery of the drive shaft 6 and is rotatably supported, and the lower end portion of the link member 14 is linked to a cam nose portion 12a extending to the side. On the lower surface of the swing cam 12, there are a base circle surface 15a that forms a concentric arc with the drive shaft 6, and a cam surface 15b that extends in a predetermined curve from the base circle surface 15a to the end portion 12a. The base circle surface 15a and the cam surface 15b are formed so as to come into contact with the upper surface of the valve lifter 11 in accordance with the swing position of the swing cam 12.
[0035]
That is, the base circle surface 15a is a section where the lift amount becomes 0 as a base circle section, and when the swing cam 12 swings and the cam surface 15b contacts the valve lifter 11, it gradually lifts. . A slight ramp section is provided between the base circle section and the lift section.
[0036]
An extension line L of the central axis of the valve stem 4 of the intake valve with respect to the rocking center Q of the rocking cam 12, that is, the axis Q of the drive shaft 6, is the right axis in FIG. It is configured to be located on the R side (details will be described later, not shown in FIG. 2).
[0037]
  As shown in FIG. 1, the control shaft 8 is configured to rotate within a predetermined rotation angle range by a lift / operation angle control hydraulic actuator 16 provided at one end. The hydraulic pressure supply to the lift / operating angle control hydraulic actuator 16 is controlled by the first hydraulic control unit 18 based on a control signal from the engine control unit 17. The actuator 16 is driven by this actuator 16.hydraulicIs configured to urge the intake valve to the small lift / small operating angle side under the condition of OFF.
[0038]
The operation of the variable lift / operating angle mechanism 1 will be described. When the drive shaft 6 rotates, the link arm 13 moves up and down by the cam action of the eccentric cam 7, and the rocker arm 10 swings accordingly. The rocking motion of the rocker arm 10 is transmitted to the rocking cam 12 via the link member 14, and the rocking cam 12 rocks. By the cam action of the swing cam 12, the valve lifter 11 is pressed and the intake valve is lifted.
[0039]
Here, when the angle of the control shaft 8 changes via the lift / operating angle control hydraulic actuator 16, the initial position of the rocker arm 10 changes, and consequently, the initial swing position of the swing cam 12 changes.
[0040]
For example, if the eccentric cam portion 9 is positioned upward in the drawing, the rocker arm 10 is positioned upward as a whole, and the cam nose portion 12a of the swing cam 12 is relatively lifted upward. That is, the initial position of the swing cam 12 is inclined in a direction in which the cam surface 15 b is separated from the valve lifter 11. Therefore, when the swing cam 12 swings with the rotation of the drive shaft 6, the base circle surface 15a continues to be in contact with the valve lifter 11 for a long time, and the period during which the cam surface 15b contacts the valve lifter 11 is short. Therefore, the lift amount is reduced as a whole, and the angle range from the opening timing to the closing timing, that is, the operating angle is also reduced.
[0041]
On the contrary, if the eccentric cam portion 9 is positioned downward in the figure, the rocker arm 10 is positioned downward as a whole, and the end 12a of the swing cam 12 is relatively pushed downward. That is, the initial position of the swing cam 12 is inclined in the direction in which the cam surface 15 b approaches the valve lifter 11. Therefore, when the swing cam 12 swings as the drive shaft 6 rotates, the portion that contacts the valve lifter 11 immediately shifts from the base circle surface 15a to the cam surface 15b. Therefore, the lift amount is increased as a whole, and the operating angle is increased.
[0042]
Since the position of the eccentric cam portion 9 can be continuously changed, the valve lift characteristic continuously changes as shown in FIG. That is, the lift and the operating angle can be continuously expanded and contracted simultaneously. In particular, in this case, the opening timing and closing timing of the intake valve change substantially symmetrically as the lift and operating angle change.
[0043]
Next, as shown in FIG. 1, the phase variable mechanism 2 rotates the sprocket 19 provided at the front end of the drive shaft 6 and the sprocket 19 and the drive shaft 6 relatively within a predetermined angle range. And a hydraulic actuator 20 for phase control. The sprocket 19 is linked to the crankshaft via a timing chain or a timing belt (not shown). The hydraulic pressure supply to the phase control hydraulic actuator 20 is controlled by the second hydraulic control unit 21 based on a control signal from the engine control unit 17. By the hydraulic pressure control to the phase control hydraulic actuator 20, the sprocket 19 and the drive shaft 6 rotate relatively, and the lift center angle is retarded as shown in FIG. That is, the lift characteristic curve itself does not change, and the whole advances or retards. This change can also be obtained continuously. The phase variable mechanism 2 is not limited to a hydraulic one, and various configurations such as one using an electromagnetic actuator are possible.
[0044]
The lift / operating angle variable mechanism 1 and the phase variable mechanism 2 may be controlled by providing a sensor for detecting an actual lift / operating angle or phase and performing a closed loop control, or depending on operating conditions. It is also possible to simply perform open loop control.
[0045]
FIG. 5 shows a multi-link type piston stroke variable mechanism 24 proposed by the same applicant as the present application.
[0046]
The piston stroke variable mechanism 24 is connected to a piston 25 of each cylinder with an upper link 27 connected at one end via a piston pin 26 and to the other end of the upper link 27 so as to be swingable via an upper link pin 28. And a lower link 31 connected to the crankpin 30 of the crankshaft 29, a control shaft 32 extending substantially parallel to the crankshaft 29, one end of which is swingably connected to the control shaft 32 and the other end. Has a control link 34 slidably connected to the lower link 31 via a control link pin 33.
[0047]
A pin journal (not shown) rotatably supported by a bearing (not shown) provided at one end of the control link 34 is intermittently formed in the control shaft 32 in the axial direction of the crankshaft 29. Yes.
[0048]
The rotation center P1 of the pin journal is eccentric by a predetermined amount with respect to the rotation center P2 of the control shaft 32, and the control link 34 swings with respect to the control shaft 32 using the rotation center P1 as a swing fulcrum.
[0049]
Therefore, when the control shaft 32 rotates, the position of the swing fulcrum P1 of the control link 34 changes, and the piston top dead center position changes accordingly. That is, the compression ratio ε of the internal combustion engine defined by the ratio of the combustion chamber side volume at the piston top dead center position to the combustion chamber side volume at the piston bottom dead center position can be increased or decreased.
[0050]
The control shaft 32 is rotationally driven using an actuator 37 connected via a worm 35 and a worm wheel 36 as a drive source, and the actuator 37 is driven and controlled by the engine control unit 17 in accordance with the engine operating state.
[0051]
Further, as a control of the piston stroke variable mechanism, a sensor for detecting an actual piston stroke may be provided to perform closed loop control, or simply open loop control may be performed according to operating conditions.
[0052]
FIG. 6 is an explanatory view showing the overall configuration of the combustion control system of the present invention, and includes the intake valve side variable valve mechanism of the internal combustion engine shown in FIG. 1 and the piston stroke variable mechanism shown in FIG. It is a combination.
[0053]
Here, reference numeral 38 denotes a knock sensor as a knock detection means for detecting the knocking intensity, and the detected value of the knock sensor 38 is input to the control unit 17. The actuator 37 that is a drive source of the control shaft 32 of the piston stroke variable mechanism is driven and controlled based on a command from the control unit 17.
[0054]
In the present embodiment, the rotation speed of the internal combustion engine is detected by the crank angle sensor, and the load of the internal combustion engine is detected by the opening of the throttle valve. These detected values are input to the engine control unit 17. . Reference numeral 39 denotes an ignition advance device which is an ignition timing adjusting means for adjusting the ignition timing based on a command from the engine control unit 17.
[0055]
As a means for detecting the load of the internal combustion engine, any one of intake negative pressure, intake air amount, and fuel injection amount can be used instead of the opening of the throttle valve.
[0056]
FIG. 7 shows the control characteristic of the compression ratio ε determined only by the change in the volume of the combustion chamber due to the piston stroke in the internal combustion engine in which the lift / operating angle variable mechanism 1, the phase variable mechanism 2 and the piston stroke variable mechanism are combined. Yes.
[0057]
On the other hand, the effective compression ratio ε ′ is determined by the intake valve closing timing (IVC) as shown in FIG. 8 that is optimally controlled according to the engine operating state.
[0058]
Under idle and partial load (R / L, etc.) operating conditions (1) and (2) (see FIG. 8), the lift / operating angle of the intake valve is relatively small, and IVC closes much earlier than bottom dead center. It becomes. As a result, the pump loss can be greatly reduced. However, if the compression ratio ε is equal to that of the conventional engine, the effective compression ratio ε ′ decreases and the combustion deteriorates. Therefore, as shown in FIG. Then, the compression ratio ε is increased.
[0059]
Under the driving condition (3) in the acceleration region (see FIG. 8), since it is necessary to increase the intake charging efficiency, the IVC is controlled in a direction approaching the bottom dead center. It is also necessary to prevent the occurrence of this in advance.
[0060]
In the operating condition with the fully open output, the effective compression ratio ε ′ is also increased in order to secure the maximum intake amount. Therefore, it is necessary to reduce the compression ratio ε determined by the piston stroke, and to approach that of a conventional engine under the fully open low speed condition (4) (see FIG. 8). In the fully open high speed condition (5) (see FIG. 8), the combustion is terminated before the chemical reaction such as peroxide that causes knocking proceeds, so the compression ratio ε determined by the piston stroke is low. Can be higher. Thereby, since the expansion ratio is also increased, there is an advantage that the exhaust temperature is lowered and the deterioration of the catalyst disposed in the exhaust system can be alleviated.
[0061]
In addition, the compression ratio ε determined by the lift / operating angle of the intake valve, the central angle Φ, and the piston stroke determined in accordance with the operating state in this way is controlled based on a control map prepared in advance. Ignition advance control is also performed by throttle opening or accelerator opening.
[0062]
The lift / operating angle variable mechanism shown in FIG. 9 differs from the above-described lift / operating angle variable mechanism 1 of the present invention described above in that the rocking center Q ′ (shaft axis) of the rocking cam 12 ′ is the valve stem. It is located on the extension line L ′ of the 4 ′ center line. This is the same arrangement as the conventional cam mechanism.
[0063]
In the case of the conventional cam mechanism, the cam that contacts the valve lifter rotates fully, so it is most reasonable that the center of the cam shaft is on the center line of the valve lifter, but the cam that contacts the valve lifter is of the swing cam type Since the cam does not fully rotate, a certain degree of freedom is obtained when used in combination with a valve lifter.
[0064]
FIG. 10 is a cross-sectional view showing the main part of the present invention, which is a layout in which the valve stem 4 center line is inclined to reduce the valve sandwich angle.
[0065]
The center of the valve lifter 11 is arranged on the axis R side passing through the center of the combustion chamber, that is, on the left side in FIG. 10, but the arrangement of the swing cam 11 is not changed.
[0066]
More specifically, the swing center Q of the swing cam 12 is disposed outside the center of the valve lifter 11 (on the right side in FIG. 10) with the combustion chamber as a reference, and when the intake valve is fully lifted, the valve lifter 11 The valve lifter 11 is driven so that the contact position of the rocking cam 12 with respect to the distance from the axis R is the farthest. In other words, the swing cam 12 is configured to drive the valve lifter 11 with the cam nose portion 12a facing the axis R side (left side in FIG. 10).
[0067]
If the cam nose portion 12a of the swing cam 12 is directed toward the axis R, there is no problem in such a change in the positional relationship with the valve lifter 11. Rather, the contact point between the swing cam 12 and the valve lifter 11 is the valve lifter 11. Since it is near the center, there is an effect that the moment acting on the valve lifter 11 is reduced.
[0068]
That is, a merit that the valve angle of the intake / exhaust valve can be changed in a relatively wide range can be obtained in the combination of the swing cam 12 and the valve lifter 11.
[0069]
In the case of the conventional cam drive of the engine, a large design change is required to change the valve clamping angle in this way. For example, since the position of the camshaft changes, the drive layout on the engine front side is changed entirely. In addition, when the distance between the sprockets is short, it is necessary to shift to another driving method. The layout of the upper surface of the cylinder head accompanying the change of the camshaft layout has also been completely changed, resulting in a completely new cylinder head.
[0070]
On the other hand, in the case of the change from FIG. 9 to FIG. 10, it is only necessary to change the mold such as the port shape and water jacket shape inside the cylinder head, change the processing of the valve lifter and valve stem, and change the parts such as the valve and valve seat. Therefore, many variations can be set.
[0071]
FIG. 11 shows an embodiment applied to an intake / exhaust valve. By arranging the cam nose portion 12a of the swing cam 12 to face each other, the allowable range of the intake / exhaust valve sandwiching angle θ can be increased, and the intake / exhaust valve sandwiching angle can be decreased. .
[0072]
FIG. 12 shows the effect of improving the specific output when the lift / operating angle of the intake valve is enlarged. Increase the intake valve lift and operating angle at high speed, that is, when the internal combustion engine speed is high, by reducing the valve angle by reducing the valve angle so that the average flow velocity of the intake air does not increase If it can, it can compensate for the decrease in output. This is a great advantage and merit when applied to an engine equipped with a variable lift / operation angle mechanism capable of continuously expanding and reducing the lift / operation angle of the intake valve.
[0073]
FIG. 13 shows the piston stroke characteristics obtained by the piston stroke variable mechanism 24 described above. Compared with a conventional single link crank mechanism, a multi-link piston stroke variable mechanism 24 having an upper link, a lower link, and a control link can obtain a piston stroke characteristic close to a single vibration. .
[0074]
Thus, in the case of the piston stroke characteristic close to simple vibration, the secondary vibration can be reduced, so that the vibration characteristic can be greatly improved.
[0075]
In addition, although the piston speed near the top dead center is slow, it is disadvantageous in terms of cooling loss, but the air-fuel mixture in the combustion chamber is easy to burn, and the piston falls quickly and does not convert torque immediately. Therefore, quietness is improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a variable valve mechanism.
FIG. 2 is a cross-sectional view of a main part of a lift / operating angle variable mechanism.
FIG. 3 is a characteristic diagram showing changes in lift / operating angle characteristics by a variable lift / operating angle mechanism;
FIG. 4 is a characteristic diagram showing a phase change of a valve lift characteristic by a phase variable mechanism.
FIG. 5 is an explanatory view showing a piston stroke variable mechanism in a cross-sectional view of the internal combustion engine.
FIG. 6 is an explanatory diagram showing the overall configuration of a combustion control system for an internal combustion engine.
FIG. 7 is a characteristic diagram showing control characteristics corresponding to engine operating conditions of a compression ratio ε determined by a piston stroke variable mechanism.
FIG. 8 is an explanatory diagram showing a change in the opening / closing timing of the intake valve in accordance with a change in the operating condition of the engine.
FIG. 9 is a cross-sectional view of the upper portion of the internal combustion engine in which the axis of the drive shaft is disposed on an extension line at the center of the valve lifter.
FIG. 10 is a cross-sectional view showing the main part of the present invention, and is a cross-sectional view of the upper part of the internal combustion engine in which the axis of the drive shaft is disposed outside the extension line of the valve lifter center.
FIG. 11 is a cross-sectional view of the upper portion of the internal combustion engine showing a case where the valve control system for the internal combustion engine according to the present invention is applied to an intake valve and an exhaust valve.
FIG. 12 is a characteristic diagram showing the correlation between the lift / operation angle of the intake valve and the specific output.
FIG. 13 is a characteristic diagram comparing the piston stroke characteristics of a single link type crank mechanism with the piston stroke characteristics of a multi-link type piston stroke variable mechanism.
FIG. 14 is a characteristic diagram showing the relationship between the compression ratio use range of the high expansion ratio system and the S / V ratio at the top dead center position.
FIG. 15 is a characteristic diagram showing the relationship between the valve clamping angle of the intake / exhaust valve and the S / V ratio at the top dead center position.
[Explanation of symbols]
1 ... Lift / operating angle variable mechanism
2 ... Phase variable mechanism
24 ... Piston stroke variable mechanism
4… Valve stem
6 ... Drive shaft
11 ... Valve lifter
12 ... Oscillating cam

Claims (9)

An internal combustion engine that lifts both an intake valve and an exhaust valve by swinging a swing cam that is rotatably and swingably mounted on a drive shaft ,
The swing cam is a component of a lift / working angle variable mechanism capable of simultaneously and continuously expanding and reducing the lift / working angle of the intake valve or the exhaust valve,
The variable lift / operating angle mechanism includes an eccentric cam that is rotationally driven by the drive shaft, a link arm that is rotatably fitted to the outer periphery of the eccentric cam, and an eccentric cam that is provided in parallel with the drive shaft. A rotatable control shaft provided with a portion, a rocker arm that is rotatably mounted on an eccentric cam portion of the control shaft and is rocked by the link arm, and is rotatably supported by the drive shaft, And an oscillating cam that presses a valve lifter of the intake valve or the exhaust valve by oscillating along with the rocker arm and oscillating with the rocker arm, and an eccentric cam portion of the control shaft By changing the rotational position of the intake valve or the exhaust valve, the lift / operating angle of the intake valve or the exhaust valve is simultaneously increased or decreased, and the rotational motion of the drive shaft is controlled by the swing cam. Configured to convert the motion,
The drive shaft is located above the valve lifter disposed at the upper end of the corresponding valve stem when viewed in the axial direction, and interlocked with the crankshaft via a sprocket provided at the end,
The swing cam coincides with the drive shaft rotation center above the valve lifter when viewed in the axial direction of the drive shaft, and during the engine operation, the swing cam also swings even when there is no valve lift. In an internal combustion engine configured to perform dynamic motion,
An internal combustion engine characterized in that the center line of both the valve stems of the intake valve and the exhaust valve is located on the axis line passing through the center of the combustion chamber with respect to the swing center of the swing cam. A piston stroke variable mechanism for changing the piston top dead center position, and a means for detecting the rotational speed and load of the internal combustion engine, and the piston stroke variable mechanism and the lift 2. The control system for an internal combustion engine according to claim 1 , wherein the control mechanism controls an operating angle variable mechanism. When the load of the internal combustion engine is small, the piston stroke variable mechanism is controlled so that the compression ratio ε of the internal combustion engine becomes high, and the closing timing of the intake valve is kept away from the bottom dead center, thereby effectively reducing the effective compression of the internal combustion engine. The control system for an internal combustion engine according to claim 2 , wherein the ratio ε ′ is lowered. The piston stroke variable mechanism includes an upper link having one end connected to a piston pin of a piston, a lower link connected to the upper link and a crank pin of a crankshaft, and a control shaft extending substantially parallel to the crankshaft. A control link having one end pivotably connected to the control shaft and the other end connected to the lower link, the swing center with respect to the control shaft being eccentric with respect to the rotation center of the control shaft; the have internal combustion engine control system according to claim 2 or 3, by rotating the control shaft, characterized by changing the piston top dead center position. Wherein the piston stroke variable mechanism, an internal combustion engine according to any one of claims 2 to 4, characterized in that the stroke characteristic related crank rotation of the piston, and a substantially single vibration. In the rotational speed is high state of the internal combustion engine, the internal combustion engine according to any one of claims 2 to 5, characterized in that expanding control the intake valve and the exhaust valve, or a lift operating angle of the one Control system. As detection means for loading of the internal combustion engine, intake negative pressure, the intake air amount, an internal combustion engine according to any of claims 2-6, characterized in that using either of the throttle opening or the fuel injection amount Control system. When the swing center of the swing cam is disposed outside the center of the valve lifter with respect to the axis passing through the center of the combustion chamber, and when the intake valve and / or the exhaust valve is fully lifted, The internal combustion engine according to any one of claims 1 to 7 , wherein the valve lifter is driven so that a contact position of the swing cam with respect to the valve lifter is farthest from the axis passing through the center of the combustion chamber. Internal combustion engine according to any of claims 1-8, characterized in that it has a phase variable mechanism for indolent phase of the lift center angle of the intake valve.

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