JP4075448B2 - Hydraulic control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to two types of hydraulic operation mechanisms that function independently of each other while sharing a hydraulic pressure source, and more particularly, to a hydraulic control device for an internal combustion engine that includes an intake valve phase change mechanism and a valve stop mechanism.
[0002]
[Prior art]
In the field of internal combustion engines, it is a common practice to operate various hydraulic operating mechanisms using an oil pump used for circulating lubricating oil as a hydraulic source. Examples of such a hydraulic operation mechanism include a valve stop mechanism that temporarily stops the opening / closing of intake / exhaust valves of some cylinders according to engine operating conditions. The valve stop mechanism described above is applied to a multi-cylinder internal combustion engine that performs so-called cylinder number control in which some cylinders are deactivated and only some cylinders are activated at the time of partial load. The intake / exhaust valves of the cylinder group to be stopped, at least the intake valves are provided to stop.
[0003]
As a hydraulic operation mechanism, a variable valve mechanism that changes opening / closing timings and valve lift amounts of intake valves and exhaust valves according to engine operating conditions is also known. As a hydraulic variable valve mechanism, Japanese Patent Application Laid-Open No. 5-248217 discloses switching the opening / closing timing of an intake valve and an exhaust valve in two stages by switching between a low-speed rocker arm and a high-speed rocker arm. Although a possible variable valve mechanism has been disclosed, a phase change mechanism for delaying the phase of the intake / exhaust valve operating angle (phase with respect to the crankshaft) is also known and has already been put into practical use.
[0004]
[Problems to be solved by the invention]
The above valve stop mechanism can be used in combination with a variable valve mechanism such as a phase change mechanism. However, when the valve stop mechanism and the phase change mechanism are provided in this way, the engine operating conditions change and all cylinders change. When switching the valve stop mechanism to shift from the operating state to the resting state of some cylinders, it is usually necessary to operate the phase change mechanism simultaneously with changes in engine operating conditions. There is a risk that the hydraulic pressure supplied to the engine will be insufficient and the response of the operation will be reduced. In order to prevent such a decrease in operation responsiveness, it may be possible to provide a dedicated oil pump, an accumulator, or the like. In this case, however, the configuration of the hydraulic circuit becomes complicated, resulting in an increase in weight and cost. There is a fear.
[0005]
The present invention has been made in view of such problems, and in the case where a valve stop mechanism and a phase change mechanism that share a hydraulic pressure source are provided, the operation responsiveness of the valve stop mechanism can be improved with a simple structure. The purpose is to plan.
[0006]
[Means for Solving the Problems]
In the present invention, the internal combustion engine includes a first cylinder group and a second cylinder group. The first cylinder group includes a first phase change mechanism that delays the phase of the operating angle of the intake valve, and a plurality of cylinders that burn at equal intervals so that stable operation is possible when only the first cylinder group is operating. Consists of. The second cylinder group also includes a second phase change mechanism that similarly delays the phase of the operation angle of the intake valve, and temporarily opens and closes the intake valve by supplying hydraulic pressure from a hydraulic source that is shared with the second phase change mechanism. The valve stop mechanism which stops automatically is provided. Therefore, for example, under a predetermined operating condition such as a partial load, the second cylinder group is in a stopped state, and at the same time, the valve stop mechanism stops the opening and closing of the intake valve of the second cylinder group. The valve stop mechanism may stop both the intake valve and the exhaust valve. Then, the hydraulic control system of the present invention, the supply hydraulic fluid second phase change mechanism of the second cylinder group is discharged from the second phase change mechanism when operating the advance side to the valve stop Organization As described above, a reflux oil passage is provided between the second phase change mechanism and the valve stop mechanism.
[0007]
Therefore, when the valve stop mechanism is switched to the valve stop state, if the second phase change mechanism operates toward the advance side almost simultaneously, the hydraulic oil discharged from the second phase change mechanism is supplied to the valve stop mechanism. As a result, the valve stop mechanism immediately switches as the hydraulic pressure is supplied from the hydraulic source. That is, the operation responsiveness of the valve stop mechanism is improved by using the hydraulic oil that is normally discharged as it is.
[0008]
【The invention's effect】
According to this invention, when switching to the valve stop, the hydraulic oil discharged from the second phase change mechanism is supplied to the valve stop mechanism through the reflux oil passage, so that a special hydraulic auxiliary device such as an accumulator is used separately. In addition, the operation response of the valve stop mechanism can be improved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a V-type 8-cylinder internal combustion engine will be described in detail with reference to the drawings. First, the combustion interval of the V-type 8-cylinder internal combustion engine will be described. FIG. 6 shows a cylinder arrangement of a V-type 8-cylinder internal combustion engine, in which the left bank 1 and the right bank 2 are arranged in a V-type with a bank angle of 90 °. The left bank 1 includes four cylinders # 1, # 3, # 5, and # 7, and the right bank 2 includes # 2, # 4, # 6, and # 8 cylinders. The four cylinders are included. The V-type 8-cylinder internal combustion engine of the present embodiment is a so-called one-plane crankshaft type in which the crankpin is disposed at a point 180 degrees apart, and the ignition order of the eight cylinders is shown in FIG. Thus, “# 1 → # 4 → # 5 → # 2 → # 7 → # 6 → # 3 → # 8 →”, and each combustion interval is 90 °. Looking at this for each bank, the left bank 1 is “# 1 → # 5 → # 7 → # 3 →” with a combustion interval of 180 °, and the right bank 2 is also with a combustion interval of 180 °. “# 4 → # 2 → # 6 → # 8 →”. That is, all banks are equally spaced combustion. Accordingly, in this embodiment, the first cylinder group in which four cylinders in one bank, for example, the right bank 2 are always operated, is the second cylinder group in which the other bank, that is, the four cylinders in the left bank 1 can be stopped depending on the operating conditions. It has become. When the operation is performed only with the first cylinder group of the right bank, as described above, ignition is performed at equal intervals of 180 ° in the order of “# 4 → # 2 → # 6 → # 8 →”. Therefore, stable operation is possible with the cylinders of the left bank 1 being deactivated, and output can be improved by reducing exhaust interference.
[0010]
The left bank 1 serving as a deactivated cylinder is provided with a valve stop mechanism that stops opening and closing of the intake and exhaust valves when the cylinder is deactivated, as will be described later. Further, a phase changing mechanism is provided for each bank in order to optimize the phase of the operating angle of the intake valve in accordance with the operating conditions. These mechanisms are all driven using the hydraulic pressure of the lubricating oil of the internal combustion engine, and the hydraulic control device will be described below. The phase change mechanism of the right bank 2 that is always operating is the first phase change mechanism, and the phase change mechanism of the left bank 1 that can be paused is the second phase change mechanism, but these are basically the same configuration. is there.
[0011]
FIG. 1 is a schematic configuration diagram showing a hydraulic control device according to the present invention, and particularly shows a configuration on the left bank 1 side that can be stopped. As shown in the figure, this hydraulic control device supplies hydraulic pressure to the second phase change mechanism 12 and the valve stop mechanism 14 as necessary, and hydraulically feeds an oil pump 10 that circulates lubricating oil to each part of the internal combustion engine. Shared as a source. A phase change hydraulic control valve 16 that controls the hydraulic pressure supplied from the oil pump 10 to the second phase change mechanism 12 and a valve that controls the hydraulic pressure supplied from the oil pump 10 to the second hydraulic operation mechanism 14. A stop hydraulic control valve 18 is provided.
[0012]
The structure of the second phase change mechanism 12 is known, and will be briefly described with reference to FIG. 2. The phase change mechanism 12 is an outer peripheral side that rotates integrally with the cam sprocket 21 that rotates in synchronization with the crankshaft. A gear portion 22, an inner peripheral gear portion 24 which is coaxially disposed inside the outer peripheral gear portion 22 and rotates integrally with an intake camshaft 23 for driving the intake valve, and the outer peripheral gear portion 22, A substantially annular piston 25 that meshes with the inner and outer peripheral surfaces of the inner peripheral side gear portion 24 via a helical spline, and a return spring 26 that urges the piston 25 to the retard side.
[0013]
A retard-side hydraulic chamber 27 and an advance-side hydraulic chamber 28 face both end surfaces of the piston 25 in the axial direction, and the piston 25 moves in the axial direction in accordance with the hydraulic pressure of the hydraulic chambers 27 and 28. The phase of the intake camshaft 23 with respect to the cam sprocket 21 is changed, and the operating angle phase of the intake valve is continuously changed.
[0014]
The structure of the valve stop mechanism 14 is also known, and will be briefly described with reference to FIG. 3. When the hydraulic pressure of the valve stop hydraulic chamber 31 is low, the rod-shaped coupling 33 is caused by the spring force of a spring (not shown). It protrudes to a position where it engages with an auxiliary rocker arm 36 a having a roller type cam follower 34, and the pressing force of the cam 35 passes through the auxiliary rocker arm 36 a, the coupling 33 and the rocker arm 36, and the intake / exhaust valve 37 (intake valve 37 a and exhaust valve 37 b). ) And a normal opening / closing operation is performed. On the other hand, when a predetermined operating oil pressure is supplied to the valve stop hydraulic chamber 31, the piston 38 presses the coupling 33 in a backward direction against the spring force of the spring to separate from the auxiliary rocker arm 36a, and the auxiliary rocker arm 36a The rocker arm 36 is substantially separated. Accordingly, power transmission from the cam 35 to the rocker arm 36 is interrupted, and the intake / exhaust valve 37 stops. In other words, when the cylinder group of the left bank 1 is stopped, the hydraulic pressure is supplied to the valve stop mechanism 14 and the intake / exhaust valve 37 is held closed.
[0015]
Next, the circuit configuration of the hydraulic control apparatus will be described with reference to FIGS. The circuit includes a first hydraulic supply oil passage 41 that supplies hydraulic pressure from the oil pump 10 to the phase change hydraulic control valve 16 and a second hydraulic supply that supplies hydraulic pressure from the oil pump 10 to the valve stop hydraulic control valve 18. The oil passage 42, the retard control oil passage 43 that connects the phase change hydraulic control valve 16 and the retard hydraulic chamber 27, and the phase change hydraulic control valve 16 and the advance hydraulic chamber 28 are connected. An advance angle side control oil passage 44, a valve stop control oil passage 45 connecting the valve stop hydraulic control valve 18 and the valve stop hydraulic chamber 31, and an oil pan from the phase change hydraulic control valve 16 during the retard operation. 11 is provided with a retarded-side drain oil passage 46 for discharging the hydraulic oil to the valve 11 and a valve stop drain oil passage 47 for discharging the hydraulic oil from the valve stop hydraulic control valve 18 to the oil pan 11.
[0016]
The hydraulic fluid discharged from the retarded hydraulic chamber 27 during the advance operation is communicated with the retarded hydraulic chamber 27 of the second phase change mechanism 12 and the valve stop hydraulic chamber 31 of the valve stop mechanism 14. A reflux oil passage 48 for supplying the valve stop hydraulic chamber 31 is provided. The reflux oil passage 48 includes the retard angle side control oil passage 43, and joins the valve stop control oil passage 45 on the downstream side. That is, the leading end of the reflux oil passage 48 is connected to the valve stop control oil passage 45 between the valve stop hydraulic control valve 18 and the valve stop hydraulic chamber 31, and the valve stop hydraulic control valve 18 is opened and closed. Regardless of the state, the hydraulic oil can be supplied to the valve stop control oil passage 45.
[0017]
A check valve 49 that prevents the backflow of hydraulic oil in the direction from the valve stop mechanism 14 toward the second phase change mechanism 12 is disposed in the reflux oil passage 48. Further, an advance side drain branch oil passage 50 is provided which branches to the upstream side (phase change mechanism 12 side) of the return oil passage 48 from the check valve 49 and extends to the oil pan 11. A control valve 51 including a check valve is disposed in the drain branch oil passage 50. The valve opening load of the check valve 49 is set lower than the valve opening load of the control valve 51. For example, the valve opening load of the check valve 49 is about 0.1 kgf / cm ² , and the valve opening load of the control valve 51 is Is set to about 0.3 kgf / cm ² .
[0018]
FIG. 8 shows a circuit configuration on the right bank 2 side that is always operating. As described above, the first phase change mechanism 12 ′ is provided on the right bank 2 side. The first phase change mechanism 12 ′ itself has the same configuration as the second phase change mechanism 12. In addition, the configuration of the hydraulic circuit is the same except for the portion of the reflux oil passage 48, and therefore, the same reference numerals are given to the same portions as the above-described configuration. In this embodiment, the oil pump 10 serving as a hydraulic pressure source is shared with the hydraulic circuit on the left bank 1 side, and from the oil pump 10 to the hydraulic control valve 16 for phase change as in the configuration on the left bank 1 side described above. The first hydraulic pressure supply oil passage 41 that supplies the hydraulic pressure, the retard side control oil passage 43 that connects the phase change hydraulic control valve 16 and the retard side hydraulic chamber 27, the phase change hydraulic control valve 16 and the advance angle. An advance side control oil passage 44 that connects the side hydraulic chamber 28 and a retard side drain oil passage 46 that discharges hydraulic oil from the phase change hydraulic control valve 16 to the oil pan 11 during the retard operation are provided. ing. The right bank 2 side is not provided with the reflux oil passage 48, and the hydraulic oil pushed out from the advance side hydraulic chamber 28 during the advance operation operates through the advance side drain oil passage 52 to change the phase. 16 is discharged to the oil pan 11.
[0019]
Next, the operation of the embodiment configured as described above will be described.
[0020]
The first and second phase change mechanisms 12 'and 12 control the position of the spool 16a by variably controlling the duty ratio of the pulse signal applied to the solenoid that drives the spool 16a of the phase change hydraulic control valve 16. The direction of the hydraulic pressure acting on each of the phase change mechanisms 12 ', 12 is switched to change the position of the piston 25, and the operation angle phase of the intake valve corresponding to this is controlled.
[0021]
Specifically, at the time of retarding operation in which the operating angle phase of the intake valve is changed to the retard side, the spool 16a of the phase changing hydraulic control valve 16 is set to the position shown in FIG. The hydraulic pressure is supplied to the retard side hydraulic chamber 27 via the first hydraulic supply oil path 41 and the retard side control oil path 43, while proceeding through the advance side control oil path 44 and the retard side drain oil path 46. The hydraulic oil in the corner side hydraulic chamber 28 is discharged to the oil pan 11. As a result, the piston 25 is pressed and moved to the retard side (left side in FIG. 2). FIG. 2A shows the lift characteristics of the intake valve and the exhaust valve in the most retarded state.
[0022]
At the time of an advance operation for changing the operating angle phase of the intake valve to the advance side, the spool position shown in FIG. 2B is set, and the advance side hydraulic pressure is passed through the first hydraulic supply oil passage 41 and the advance side control oil passage 44. While hydraulic pressure is supplied to the chamber 28, hydraulic oil in the retarded hydraulic chamber 27 is discharged through the retarded control oil passage 43. This hydraulic oil is discharged to the valve stop control oil passage 45 via the reflux oil passage 48 on the left bank 1 side, and is discharged to the oil pan 11 by the advance side drain oil passage 52 on the right bank 2 side. As a result, the piston 25 is pressed and moved to the advance side (the right side in FIG. 2). FIG. 2 (b) shows the lift characteristics of the intake valve and the exhaust valve in the most advanced state.
[0023]
When the operating angle phase of the intake valve is maintained at the current phase, the spool position shown in FIG. 2C is set, and both of the spool 16a are connected to the retard side control oil path 43 and the advance side control oil path 44. Are closed, the hydraulic pressure in the hydraulic chambers 27 and 28 is locked, and the piston 25 is held at the current position.
[0024]
In this way, by switching the hydraulic pressure supplied to the phase change mechanisms 12 'and 12 via the phase change hydraulic control valve 16, it is possible to feedback control the operating angle phase of the intake valve to a characteristic according to the engine operating conditions. .
[0025]
On the other hand, in the valve stop mechanism 14 provided on the left bank 1 side, as shown in FIG. 1 and FIG. 4, the position of the spool 18a of the valve stop hydraulic control valve 18 is switched according to the engine operating conditions. The valve opening / closing movement is temporarily stopped in accordance with switching between operation and stop of the cylinder group on the bank 1 side. That is, when the cylinder group on the left bank 1 side is operated, the spool position shown in FIG. 4A is set, and the hydraulic oil in the valve stop hydraulic chamber 31 is supplied to the valve stop control oil passage 45 and the valve stop drain oil passage. 47 is discharged to the oil pan 11. On the other hand, when the cylinder group on the left bank 1 side is stopped, the spool position shown in FIG. 4B is set, and the oil pressure of the oil pump 10 is increased via the second hydraulic pressure supply oil passage 42 and the valve stop control oil passage 45. Supplied to the valve stop hydraulic chamber 31. As a result, the opening and closing of the intake valve and the exhaust valve are stopped as described above.
[0026]
Here, in this embodiment, when the valve stop is performed in the cylinder group on the left bank 1 side as described above, the second phase change mechanism 12 of the cylinder group on the left bank 1 side simultaneously operates toward the advance side. To do. When the second phase changing mechanism 12 is advanced in this way, hydraulic oil is discharged from the retarded-side hydraulic chamber 27 to the return oil passage 48 as the piston 25 moves forward. The hydraulic pressure in the valve stop control oil passage 45 is increased to some extent. Therefore, when the valve stop hydraulic control valve 18 is switched so as to supply the hydraulic pressure to the valve stop mechanism 14 under such circumstances, the hydraulic pressure introduced to the valve stop mechanism 14 is quickly increased, and the valve stop immediately Switch to state. That is, in addition to the hydraulic fluid supplied from the oil pump 10 to the valve stop hydraulic chamber 31 via the second hydraulic supply oil passage 42, the valve stop hydraulic control valve 18, and the valve stop control oil passage 45, The hydraulic oil is also supplied from the corner side hydraulic chamber 27 side via the reflux oil passage 48. Therefore, the retard side hydraulic chamber 27 functions as a kind of hydraulic accumulator, and the operation responsiveness of the valve stop mechanism 14 can be improved without providing a separate accumulator or the like.
[0027]
In particular, when the engine speed is low, the hydraulic pressure supplied from the oil pump 10 itself is low, so that the operation responsiveness tends to decrease. However, according to this embodiment, the hydraulic oil is also supplied from the retard side hydraulic chamber 27. Therefore, it is possible to obtain good operation responsiveness even in such an operation region where the supply pressure is low.
[0028]
More specifically, the reflux oil passage 48 joins the valve stop control oil passage 45 connecting the valve stop hydraulic control valve 18 and the valve stop hydraulic chamber 31, and passes through the valve stop hydraulic control valve 18. The hydraulic oil is directly supplied to the valve stop hydraulic chamber 31 without any problem. Therefore, the operation responsiveness is reliably improved.
[0029]
Here, in the present embodiment, the cylinder group on the left bank 1 side becomes a deactivated cylinder when the valve is stopped, so it is not necessary to move the second phase change mechanism 12 originally, but the right bank 2 side which is an operating cylinder side. By actively continuing the same phase control as that of the first cylinder group, the first phase changing mechanism 12 is operated to the advance side when the valve stop is switched. That is, FIG. 5 shows the relationship between the advance angle region H1 where the first and second phase change mechanisms 12 ′ and 12 are controlled to the advance position and the cylinder deactivation region H2 where the cylinder group on the left bank 1 side is deactivated. The cylinder deactivation region H2 is included in the advance angle region H1. In other words, in this embodiment, in the partial load region, some cylinders are deactivated and the operating angle phase of the intake valve of the working cylinder is advanced to increase the internal EGR, thereby improving fuel consumption and reducing NOx. Yes.
[0030]
Therefore, for example, as shown by an arrow A1 in FIG. 5, in a situation where the rotation speed increases from a low rotation and low load range near the idle, the first is almost simultaneously with the stop (valve stop) of the cylinder group on the left bank 1 side. The second phase changing mechanisms 12 'and 12 are about to change to the advance side. Further, as shown by the arrow A2, in the situation where the rotational speed is reduced from the high rotational speed and low load range in which all the cylinders are operating, the first and second phase change mechanisms 12 ′ and 12 are also advanced. While changing to, the switching to the cylinder deactivation operation is started. Furthermore, as shown by the arrow A3, in a situation where the torque decreases from the high load range, the control characteristics of the first and second phase change mechanisms 12 ′ and 12 are basically within the advance angle range H1. However, since the phase control characteristic is set to a characteristic that is relatively retarded on the high load side as compared with the middle load region, the first and second phase change mechanisms 12 are changed in accordance with the change of the arrow A3. ', 12 slightly changes to the advance side. Accordingly, when the first and second phase change mechanisms 12 'and 12 are gradually changing to the advance side, switching to cylinder deactivation (valve stop) is started.
[0031]
In this way, by performing phase control on the left bank 1 side, which is a deactivated cylinder, in the same manner as the right bank 2 side, the second phase change mechanism 12 is simultaneously operated toward the advance side when switching to the valve stop state. In other words, since the hydraulic oil is supplied to the valve stop hydraulic chamber 31 through the reflux oil passage 48, the operation responsiveness at the start of the cylinder deactivation operation is effectively improved while having a simple structure. Can be made.
[0032]
Note that the second phase change mechanism 12 moves to the advance side in a situation where the hydraulic pressure on the downstream side of the check valve 49 is high and the check valve 49 cannot be opened as in the case where the cylinder deactivation operation is continuously performed. When operated, the control valve 51 opens, and the hydraulic oil in the retard side hydraulic chamber 27 can be reliably discharged to the oil pan 11 via the advance side drain branch oil passage 50. .
[0033]
Further, when all cylinders are in an operating state, the valve opening load of the check valve 49 is lower than the valve opening load of the control valve (check valve) 51 and the hydraulic pressure downstream of the check valve 49 is low. When the mechanism 12 moves forward, only the check valve 49 opens. Accordingly, the hydraulic oil in the retard side hydraulic chamber 27 is discharged to the oil pan 11 through the reflux oil passage 48, the valve stop control oil passage 45 and the valve stop drain oil passage 47.
[0034]
As described above, the present invention has been described based on a preferred embodiment, but the present invention is not limited to this embodiment, and includes various modifications and changes. For example, instead of the control valve 51, an orifice that generates a pressure difference may be provided.
[0035]
In the above embodiment, the phase control of the intake valve of the cylinder group on the left bank 1 side is always performed in the same manner as on the right bank 2 side. However, the second phase on the left bank 1 side is switched to the rest operation. It is also possible to positively move only the changing mechanism 12 toward the advance side, so that the operation responsiveness of the valve stop mechanism 14 can be improved more reliably.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a circuit configuration on a left bank side in a hydraulic control apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating the operation of a phase change mechanism and its hydraulic control valve.
FIG. 3 is a perspective view showing a valve stop mechanism.
FIG. 4 is an operation explanatory view schematically showing a valve stop hydraulic control valve.
FIG. 5 is a characteristic diagram showing an advance angle region and a cylinder deactivation region of the phase change mechanism.
FIG. 6 is an explanatory view showing a cylinder arrangement of a V-type 8-cylinder internal combustion engine.
FIG. 7 is an explanatory diagram of an ignition sequence of a 1-plane crankshaft format.
FIG. 8 is a configuration diagram showing a circuit configuration on the right bank side.
[Explanation of symbols]
10 ... Oil pump (hydraulic power source)
12 ... Second phase change mechanism 14 ... Valve stop mechanism 48 ... Recirculation oil passage 49 ... Check valve 50 ... Advance side drain branch oil passage 51 ... Control valve

Claims (7)

A first phase change mechanism that includes a first phase change mechanism that retards the phase of the operating angle of the intake valve, and a second phase change that similarly delays the phase of the operating angle of the intake valve; And a second cylinder group including a valve stop mechanism that temporarily stops opening and closing of the intake valve by supplying hydraulic pressure from a hydraulic pressure source shared with the second phase change mechanism. Because
As the hydraulic oil discharged from the second phase changing mechanism is supplied to the valve stop Organization when the second phase change mechanism of the second cylinder group is operated to the advance side, the second phase change A hydraulic control device for an internal combustion engine, wherein a reflux oil passage is provided between the mechanism and the valve stop mechanism. A valve stop hydraulic control valve is provided between the hydraulic source and the valve stop mechanism, and a leading end of the reflux oil passage is an oil passage between the valve stop hydraulic control valve and the valve stop mechanism. The hydraulic control device for an internal combustion engine according to claim 1, wherein the hydraulic control device is connected to the internal combustion engine. 3. The internal combustion engine according to claim 1, wherein a check valve that prevents backflow of hydraulic oil from the valve stop mechanism to the second phase change mechanism is disposed in the reflux oil passage. Hydraulic control device. A control valve is provided in a drain branch oil passage that branches off upstream of the check valve in the reflux oil passage and discharges hydraulic oil, and the valve opening load of the control valve is larger than the valve opening load of the check valve. 4. The hydraulic control apparatus for an internal combustion engine according to claim 3, wherein the hydraulic control apparatus is set high. 5. The hydraulic pressure of the internal combustion engine according to claim 1, wherein the first phase change mechanism, the second phase change mechanism, and the valve stop mechanism share the same hydraulic pressure source. Control device. The internal combustion engine is a one-plane crankshaft V-type 8-cylinder internal combustion engine, wherein one bank of cylinders constitutes a first cylinder group and the other bank of cylinders constitutes a second cylinder group. The hydraulic control device for an internal combustion engine according to any one of claims 1 to 5. The internal combustion engine according to any one of claims 1 to 6, wherein when the valve stop mechanism is switched to a valve stop state, the second phase change mechanism is controlled to change to an advance side. Hydraulic control device.

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