JP3123374B2 - Variable valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve apparatus for variably controlling a valve lift characteristic of an intake valve or an exhaust valve of an internal combustion engine (both are generally referred to as intake and exhaust valves) in accordance with engine operating conditions. .

[0002]

2. Description of the Related Art In general, a valve train for an internal combustion engine transmits a cam lift to intake and exhaust valves via a rocker arm and a swing arm, and pushes open and exhaust valves urged in a closing direction by a valve spring. However, since, for example, preferable valve lift characteristics are different between a low-speed region and a high-speed region of the engine, various variable valve operating devices capable of switching the valve lift characteristics depending on operating conditions have been proposed. One example is disclosed in, for example, JP-A-63-167016.
In Japanese Unexamined Patent Application Publication No. H10-207, a low-speed cam and a high-speed cam having different profiles are arranged side by side on a camshaft, and a driven main rocker arm and a sub-rocker arm are switched to a connected state or a disconnected state as necessary. Configurations are known. In general, a high-speed cam is set to have both a larger cam lift and a longer valve opening period than a low-speed cam.

[0003] In addition, some variable valve actuating devices using a valve timing adjustment mechanism for delaying the valve timing of opening and closing the intake and exhaust valves by changing the phase of the camshaft with respect to the crankshaft have been conventionally used. Has been put to practical use. That is, in this case, the operating center angle (the crank angle that is the center between the opening timing and the closing timing) changes without changing the shape of the valve lift characteristic.

[0004] Further, there has also been proposed a variable valve actuation device in which a former valve lift adjusting mechanism by cam switching and a latter valve timing adjusting mechanism are combined. By combining the two, the valve lift can be changed in magnitude, and at the same time, the opening timing and the closing timing can be variably controlled, so that the requirements can be further adapted to the requirements under each operating condition.

[0005] Variable valve mechanisms such as these valve lift adjustment mechanisms and valve timing adjustment mechanisms are generally of a hydraulic drive type, and are provided by supplying or stopping the lubricating oil pressure of the internal combustion engine to the actuator section. Can be switched. Therefore, it has been proposed to prohibit switching of the hydraulic control valve at a low oil temperature where the oil viscosity is high and the oil passage pressure loss is large (for example, Japanese Patent Publication No. 58-386).
02 publication).

[0006]

When the switching of the oil temperature control valve is prohibited at a low oil temperature as described above, the oil temperature gradually increases from the prohibition state and the predetermined set temperature is reduced. At that moment, the switching of the hydraulic control valve is permitted, and if the engine operating condition is in the ON region of the variable valve mechanism, the hydraulic pressure is supplied to perform the switching operation of the variable valve mechanism.

However, in an internal combustion engine having a plurality of variable valve mechanisms such as the above-described valve lift adjustment mechanism and valve timing adjustment mechanism, the supply of hydraulic pressure to each variable valve mechanism at the same time as the oil temperature rises increases. If you start,
As a result, a large drop in the hydraulic pressure at the time of switching transition occurs as a whole, and as a result, the responsiveness of the switching operation of each variable valve mechanism deteriorates, the operability of the engine deteriorates, and switching mechanism components such as coupling pins in the variable valve mechanism. Inconvenience such as collision occurs. In addition, as a result of the simultaneous switching of the plurality of variable valve mechanisms, a very large torque change occurs suddenly as a whole, giving a driver an uncomfortable feeling.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a plurality of variable valves which continuously or stepwise change the valve lift characteristics of an intake valve or an exhaust valve in response to supply and stop of hydraulic pressure to an actuator. Mechanism, a plurality of hydraulic control valves for respectively controlling hydraulic pressure supply to the actuator section of each variable valve mechanism, control means for outputting a control signal to each hydraulic control valve according to engine operating conditions, and lubrication of the internal combustion engine. Oil temperature detecting means for directly or indirectly detecting the oil temperature; and when the detected oil temperature exceeds a set temperature corresponding to the completion of warming-up, the control means is permitted to supply hydraulic pressure by the hydraulic control valve. And a hydraulic pressure supply permitting means for outputting a signal to output a signal indicating that the hydraulic pressure may be supplied under the same engine operating condition among the plurality of variable valve mechanisms. The variable valve mechanism is characterized by having different the set temperature, respectively.

According to a second aspect of the present invention, there are provided a plurality of variable valve mechanisms for continuously or stepwise changing a valve lift characteristic of an intake valve or an exhaust valve in response to supply and stop of hydraulic pressure to an actuator portion. A plurality of hydraulic control valves for respectively controlling the supply of hydraulic pressure to the actuator section of the variable valve mechanism; a control means for outputting a control signal to each hydraulic control valve in accordance with engine operating conditions; Alternatively, an oil temperature detecting means for indirectly detecting, and when the detected oil temperature exceeds a set temperature corresponding to the completion of warming-up, switching of supply and stop of hydraulic pressure by the hydraulic control valve to the control means. In a variable valve operating apparatus for an internal combustion engine, comprising: a hydraulic pressure switching permitting means for outputting a permitting signal. The variable valve mechanism is characterized by having different the set temperature, respectively.

[0010] In particular, in the invention of claim 3, the set temperature of the variable valve mechanism in which the valve lift characteristic changes continuously is set lower than the set temperature of the variable valve mechanism in which the valve lift characteristic changes stepwise. .

The variable valve mechanism in which the valve lift characteristic continuously changes is, for example, a valve timing adjustment mechanism that changes the phase of a camshaft with respect to a crankshaft. The variable valve mechanism that changes stepwise is, for example, a valve lift adjustment mechanism that transmits a lift of one of a low-speed cam and a high-speed cam to an intake / exhaust valve.

[0012]

According to the first aspect of the present invention, the supply of the hydraulic pressure to the actuators of the respective variable valve mechanisms is prohibited at a low oil temperature when the warm-up of the engine is not completed. Then, when the oil temperature rises and exceeds the set temperature, supply of hydraulic pressure to each variable valve mechanism is permitted. That is, if the operating condition is in the region where the hydraulic pressure is to be supplied, the supply of the hydraulic pressure is started at that moment, and the valve lift characteristic changes. Here, since the set temperatures at which the hydraulic supply is permitted are different for the plurality of variable valve mechanisms, the hydraulic supply is sequentially executed by each variable valve mechanism. In other words, the plurality of variable valve mechanisms are not simultaneously turned ON based on the oil temperature, and deterioration of responsiveness due to a transient decrease in oil pressure is avoided.

According to the second aspect of the invention, not only the supply of the hydraulic pressure but also the switching between the supply and the stop is prohibited at a low oil temperature,
It is permitted when the temperature exceeds the set temperature.

According to the third aspect of the invention, when the oil temperature rises, first, the supply of the hydraulic pressure or the switching of the hydraulic pressure to the variable valve mechanism in which the valve lift characteristic continuously changes are permitted.
The supply of hydraulic pressure or the switching of hydraulic pressure to the variable valve mechanism in which the valve lift characteristics change stepwise are permitted.

According to a fourth aspect of the present invention, there is provided a valve timing adjusting mechanism.
By changing the phase of the camshaft with respect to the crankshaft, the valve lift characteristics are changed stepwise. The valve lift adjusting mechanism changes the valve lift characteristics in a stepwise manner by selectively transmitting either one of the low-speed cam and the high-speed cam to the intake / exhaust valve.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of a variable valve apparatus in which a valve lift adjusting mechanism 40 and a valve timing adjusting mechanism 70 are provided as variable valve operating mechanisms on the intake valve 9 side.

First, the valve lift adjusting mechanism 40 will be described. As shown in FIGS. 2 and 3, each cylinder is provided with one main rocker arm 1 corresponding to a pair of intake valves 9. The base end of the main rocker arm 1 is swingably supported by a cylinder head 69 via a main rocker shaft 3 common to each cylinder. An adjusting screw 10 that is in contact with the stem top of each intake valve 9 is fastened to the tip of the main rocker arm 1 via a nut 11.

The main rocker arm 1 has a shaft 13
The roller 14 is rotatably supported via a needle bearing, and the low-speed cam 21 is in contact with the roller 14.

The main rocker arm 1 is formed in a substantially rectangular shape in plan view, and the sub rocker arm 2 is provided in an opening formed alongside the roller 14. The base end of the sub rocker arm 2 is connected to the main rocker arm 1 via a sub rocker shaft 16 so as to be relatively rotatable. The sub rocker shaft 16 is slidably fitted in a hole 17 formed in the sub rocker arm 2, while being press-fitted into a hole 18 formed in the main rocker arm 1.

The sub rocker arm 2 does not have a portion that comes into contact with the intake valve 9, and as shown in FIG. 3, a cam follower portion 23 that is in sliding contact with the high-speed cam 22 is formed at the tip thereof so as to protrude in an arc shape. On the side, a lost motion spring 25 for pressing the cam follower portion 23 against the high-speed cam 22 is interposed.

A lost motion spring 25 is located on the main rocker arm 1 directly below the sub rocker arm 2.
Are formed integrally with each other. The lower end of the coiled lost motion spring 25 has a concave portion 26.
Of the sub rocker arm 2 via a retainer 27 that slidably fits into the recess 26.

The low-speed cam 21 and the high-speed cam 22 are integrally formed on a common camshaft 72, and have different shapes (sizes) so as to satisfy the valve lift characteristics required when the engine is running at a low speed and at a high speed. Are also included. In this embodiment, as shown in FIG. 5, the high-speed cam 22 has a profile in which both the valve lift and the operating angle (valve opening period) are larger than the low-speed cam 21.

To properly connect the two rocker arms 1 and 2, plungers 33, 31 and 34 are slidably fitted over the main rocker arm 1 and the sub rocker arm 2. A hydraulic passage 43 is connected to the rear of the plunger 33 serving as an actuator section.
A return spring 38 is provided behind the back.

When the operating oil pressure guided from the hydraulic passage 43 is low, the plungers 33, 31 are respectively accommodated in the sub rocker arm 2 and the main rocker arm 1 by the urging force of the return spring 38, and the swinging of both is not restrained. That is, both are in the detached state. On the other hand, when the operating oil pressure guided from the hydraulic passage 43 rises, the plungers 33 and 31 slide while compressing the return spring 38, and are fitted over the main rocker arm 1 and the sub rocker arm 2 so that they are integrally formed. Rocks.

The hydraulic passage 43 is provided through the inside of the main rocker arm 1 and the main rocker shaft 3, and the discharge hydraulic pressure of the oil pump 57 is guided via the electromagnetic switching valve 45 only at a predetermined high rotation. .

Next, the valve timing adjusting mechanism 70 will be described. The valve timing adjusting mechanism 70 is provided between the camshaft 72 and the cam pulley 71, and changes the phases of the two according to the operating conditions to change the opening / closing timing of the intake valve 9. The cam pulley 71 is transmitted with a torque from a crankshaft (not shown) via a timing belt 66.

As shown in FIG. 4, a cylindrical inner housing 65 is fixed to the end of the camshaft 72 via bolts 64. A cylindrical outer housing 63 rotatably fitted to the outer periphery of the inner housing 65 is provided, and a cam pulley 71 is formed integrally with the outer housing 63.

A ring-shaped helical gear 73 is interposed between the inner housing 65 and the outer housing 63. The helical gear 73 has helical splines formed on the inner and outer circumferences. Each helical spline meshes with the outer circumference of the inner housing 65 and the inner circumference of the outer housing 63, and when the helical gear 73 moves in the axial direction, the outer housing 63 Inner housing 6
5, the phase of the cam shaft 72 with respect to the cam pulley 71 changes.

A hydraulic chamber 75 is defined between the inner housing 65, the outer housing 63, and the helical gear 73, which are actuator portions. When the hydraulic pressure guided to the hydraulic chamber 75 rises above a predetermined value, the helical gear 73
Moves from the initial position in the axial direction against the return spring 74, so that the camshaft 72 rotates in a direction to advance the opening / closing timing of the intake valve 9.

That is, when the helical gear 73 is at the initial position, the opening and closing timing of the intake valve 9 is relatively late as shown in the upper and lower parts of FIG.
Is maximized, the opening / closing timing of the intake valve 9 is relatively advanced, as shown in the middle part of FIG.

In the hydraulic chamber 75, a shaft hole 78 formed in the camshaft 72, an oil gallery 59 formed in the cylinder head 69, an orifice 77, and a main gallery 58 formed in the cylinder block 68 are provided. Through this, the discharge oil pressure from the oil pump 57 is introduced.

In order to appropriately release the hydraulic pressure, an electromagnetic switching valve 79 is provided at the other end of the camshaft 72, and is controlled to open and close according to the engine operating conditions.
The electromagnetic switching valve 79 opens the shaft hole 78 as shown in the drawing when the electric power is not supplied to reduce the hydraulic pressure guided to the hydraulic chamber 75, and closes the shaft hole 78 when the electric power is supplied to increase the hydraulic pressure guided to the hydraulic chamber 75. ing.

As a control means of the valve lift adjusting mechanism 40 and the valve timing adjusting mechanism 70, a control unit 51 for controlling energization of the electromagnetic switching valve 45 and the electromagnetic switching valve 79 is provided.

The control unit 51 receives an engine rotation signal, an engine load signal, a cooling water temperature signal, a supercharging pressure signal of intake air from a supercharger, and the like. , While smoothly switching the valve lift characteristics.

Also, at an appropriate position in the lubrication system of the internal combustion engine,
An oil temperature sensor 80 for detecting the lubricating oil temperature is provided,
The detection signal is input to the control unit 51. Instead of directly detecting the lubricating oil temperature in this way, the oil temperature may be indirectly estimated from the engine cooling water temperature or the like.

Next, the operation of the above embodiment will be described.

FIG. 5 is an explanatory diagram showing control states of the valve lift adjusting mechanism 40 and the valve timing adjusting mechanism 70 with respect to the engine operating conditions. As shown in the figure, in the high engine speed range, the valve lift adjusting mechanism 40 is of a high speed type. The cam 22 is selected, and the valve timing adjusting mechanism 70 controls the opening / closing timing to be delayed. This increases the valve overlap. The electromagnetic switching valve 45 of the valve lift adjustment mechanism 40
ON corresponds to the high-speed cam 22 and OFF corresponds to the low-speed cam 21. The valve timing adjusting mechanism 70
ON of the electromagnetic switching valve 79 of the
Correspond to the lag side, respectively. That is, in the engine high speed range, the electromagnetic switching valve 45 is turned on and the electromagnetic switching valve 79 is turned off.

In the low-speed region of the engine and on the high-load side, the electromagnetic switching valve 45 is turned off and the electromagnetic switching valve 79 is turned on, so that the low-speed cam 21 and the open / close timing are advanced.

Further, in the low engine speed region and on the low load side, both solenoid-operated directional control valves 45 and 79 are turned off, so that the low speed cam 21 and the opening / closing timing are delayed.

When the electromagnetic switching valves 45 and 79 are turned on,
The OFF control is performed based on the engine operating conditions, that is, the engine load and the rotation speed, with reference to a control map given to the control unit 51 in advance. Since the electromagnetic switching valve 45 and the electromagnetic switching valve 79 are controlled based on respective control maps, the rough classification in FIG. 5 shows that both are not turned on at the same time. However, actually, the ON regions partially overlap, and both can be turned ON at the same time.

On the other hand, the control unit 51 monitors whether or not the warm-up is completed based on the oil temperature detected by the oil temperature sensor 80. If the oil temperature is equal to or lower than the set temperature, the ON operation of the electromagnetic switching valves 45 and 79 is prohibited, and the ON operation is permitted when the temperature exceeds the set temperature.

The flowcharts shown in FIG. 6 and FIG.
This shows a specific control flow. In step 1 of the main flowchart of FIG. 6, the engine operating conditions represented by the engine load and rotation speed are read, and in step 2, the valve timing adjusting mechanism 70, ie, the electromagnetic switching valve It is determined whether or not it is the ON area of No. 79. Here, if it is outside the ON region, the process proceeds to step 3 and the electromagnetic switching valve 79 is turned off. On the other hand, if it is in the ON region, the process proceeds to step 4, and the state of the first permission flag FT based on the oil temperature is determined. As for the permission flag FT, “1” indicates a state in which the ON of the electromagnetic switching valve 79 is permitted, and “0” indicates a state in which the ON is prohibited.
Therefore, only when the permission flag FT is "1" in step 4, the process proceeds to step 5, and the electromagnetic switching valve 79 is turned on. If the permission flag FT is "0", the process proceeds to step 3, where the electromagnetic switching valve 79 is turned off. Similarly, in step 6, the engine operating condition is changed to the valve lift adjusting mechanism 40.
That is, it is determined whether or not it is in the ON region of the electromagnetic switching valve 45,
If it is in the ON region, the electromagnetic switching valve 45 is turned ON on condition that the second permission flag FL is "1" indicating the ON permission state (steps 8 and 9). Otherwise, in step 7, the electromagnetic switching valve 45 is turned off.

The permission flags FT and FL are set according to the flowchart of FIG. That is, the oil temperature T detected by the oil temperature sensor 80 in step 11 is read and is
The set temperature T1 and the second set temperature T2 are compared with each other in Steps 12 and 15, respectively. If the actual oil temperature T is higher than the first set temperature T1, the first permission flag F
T is set to "1" (step 13), and when the temperature is equal to or lower than the first set temperature T1, the first permission flag FT is set to "0" (step 14). Similarly, the actual oil temperature T is equal to the second set temperature T
If it is higher than 2, the second permission flag FL is set to "1" (step 16), and if it is lower than the second set temperature T2,
The second permission flag FL is set to "0" (step 17).
Here, the first set temperature T1, which is the ON permission temperature of the valve timing adjustment mechanism 70, ie, the electromagnetic switching valve 79, is lower than the second set temperature T2, which is the ON permission temperature of the valve lift adjustment mechanism 40, ie, the electromagnetic switching valve 45. Is set.

Therefore, in this embodiment, when the warm-up of the engine progresses and the lubricating oil temperature rises, first, the ON operation of the electromagnetic switching valve 79 is permitted, and then the electromagnetic switching valve 45 is turned on.
ON operation is permitted. Therefore, even if both of the solenoid-operated directional control valves 45 and 79 are in the operating condition to be turned ON, the supply of the lubricating oil is not started at the same time, and the transient decrease in the hydraulic pressure and, consequently, the responsiveness are deteriorated. I will not invite you. Further, since the two variable valve mechanisms, that is, the valve timing adjustment mechanism 70 and the valve lift adjustment mechanism 40 are not switched at the same time, a slight time difference is given.
The torque fluctuation is reduced.

In particular, the valve timing adjusting mechanism 70 in which the valve lift characteristic continuously changes with the movement of the helical gear 73 starts operating at a lower temperature, and the plunger 3
Since the valve lift adjusting mechanism 40 in which the valve lift characteristics change stepwise by the fitting of 3, 31, and 34 starts operating on the high temperature side, the adverse effect of the decrease in responsiveness due to the viscosity of the lubricating oil is minimized. That is, the plungers 33, 31, and 34
There is no possibility of collision of each part due to poor fitting.

Next, FIG.
9 shows another embodiment of a main flowchart for switching between N and OFF. In this embodiment, at step 21, engine operating conditions represented by the load and the number of revolutions of the engine are read, and at step 22, it is determined whether or not the valve timing adjusting mechanism 70, that is, the electromagnetic switching valve 79 is in the ON region. .
Here, if it is outside the ON region, the process proceeds to step 23, and it is determined whether or not the electromagnetic switching valve 79 is in the OFF state. If it is already in the OFF state, proceed to step 25,
Keep the OFF state. In step 23, the electromagnetic switching valve 79
Is in the ON state, the routine proceeds to step 24, where the state of the first permission flag FT based on the oil temperature is determined. If the first permission flag FT is “1”, the electromagnetic switching valve 79
Means that the switching is permitted, the process proceeds to step 25, and the electromagnetic switching valve 79 is switched off. If the first permission flag FT is "0", it means that the switching is prohibited, so the process proceeds to step 28, and the ON state is maintained.

If it is determined in step 22 that the valve timing adjusting mechanism 70, that is, the electromagnetic switching valve 79 is within the ON range, the process proceeds to step 26, where the electromagnetic switching valve 79 is
It is determined whether or not the state is N. If it is already in the ON state, the process proceeds to step 28, where the ON state is maintained. If the electromagnetic switching valve 79 is in the OFF state in step 26, the process proceeds to step 27 to determine the state of the first permission flag FT based on the oil temperature. If the first permission flag FT is "1", the routine proceeds to step 25, where the electromagnetic switching valve 79
To OFF. If the first permission flag FT is "0", the process proceeds to step 28, where the ON state is maintained.

Similarly, for the valve lift adjusting mechanism 40, after determining in step 29 whether it is in the ON area or in the OFF area, in steps 30 and 33, the actual ON / OFF state of the electromagnetic switching valve 45 is determined. Then, a change in the area is determined. Then, in the OFF area and the current OF
If it is in the F state, the process proceeds to step 32 and the OFF state is maintained. If it is in the OFF area and is currently in the ON state, the second permission flag FL is determined in step 31;
Only when the flag FL is "1", the electromagnetic switching valve 4
5 is switched from ON to OFF (step 32). If it is in the ON area and is currently in the ON state, the process proceeds to step 35, and the ON state is maintained. If it is in the ON region and is currently in the OFF state, the second permission flag FL is determined in step 34, and the electromagnetic switching valve 45 is switched from OFF to ON only when the flag FL is "1" (step 34). 35).

The permission flags FT and FL are set similarly in accordance with the above-described flowchart of FIG.

Therefore, in this embodiment, when the oil temperature is low,
Not only the ON operation of each of the electromagnetic switching valves 45 and 79 but also the switching from ON to OFF is prohibited. Then, when the oil temperature becomes higher than the first set temperature T1 and the second set temperature T2, the switching is permitted. At this time, since an appropriate temperature difference is given between the two set temperatures T1 and T2,
Each switching is started sequentially. In particular, the switching of the valve timing adjustment mechanism 70 in which the valve lift characteristics continuously change with the movement of the helical gear 73 starts on the low temperature side, and the valve lift characteristics are gradually changed by the fitting of the plungers 33, 31, and 34. Variable valve lift adjustment mechanism 4
The switching of 0 starts on the hot side. Therefore, the switching of the valve timing adjustment mechanism 70 in which the decrease in responsiveness due to the viscosity of the lubricating oil is not so problematic can be started at an early stage, and the valve overlap at the time of idling can be optimized at an early stage. Also,
When the switching of the valve lift adjusting mechanism 40 is started, the oil temperature is high, so the plungers 33, 3
There is no possibility that the collision of each part due to the poor fitting of the first and the third 34 will occur.

While the present invention has been described with reference to an embodiment in which the present invention is applied to an internal combustion engine having two variable valve mechanisms on the intake side, the present invention provides an internal combustion engine having a larger number of variable valve mechanisms. Applicable to institutions. In the case where three or more variable valve mechanisms are provided, the set temperature may be made different only for those which are likely to be simultaneously turned ON under the same operating conditions.

The present invention can also be applied to a case where a variable valve mechanism is provided on each of the intake side and the exhaust side. In other words, by setting the set temperature different between the variable valve mechanism on the exhaust side and the variable valve mechanism on the intake side, it is possible to avoid deterioration of the responsiveness due to a transient decrease in oil pressure.

[0054]

As is apparent from the above description, claim 1
Alternatively, according to the second aspect of the present invention, when warm-up of the engine is completed and ON operation or switching of the variable valve mechanism is permitted, the plurality of variable valve mechanisms are simultaneously switched based on the oil temperature. Since the switching is performed sequentially without any occurrence, the deterioration of responsiveness due to a transient decrease in oil pressure can be avoided. Further, it is possible to reduce a change in torque due to switching of the valve lift characteristic.

According to the third aspect of the present invention, the variable valve mechanism in which the responsiveness at the time of switching does not generally cause a problem and the valve lift characteristic continuously changes is switched first on the low temperature side,
Since the variable valve mechanism in which the valve lift characteristics of the characteristic switching plunger tend to cause a problem in a stepwise manner is switched on the high temperature side, it is possible to prevent the failure of the latter mechanism such as collision of various parts due to poor switching of the mechanism. .

In particular, in the invention of claim 4, the switching between the low-speed cam and the high-speed cam can be reliably performed at a relatively high temperature side, and the valve timing can be optimized early from a low temperature.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of a variable valve apparatus according to the present invention.

FIG. 2 is an enlarged plan view of the rocker arm.

FIG. 3 is a sectional view of a rocker arm portion.

FIG. 4 is a sectional view of a valve timing adjustment mechanism.

FIG. 5 is a valve lift characteristic diagram of this embodiment.

FIG. 6 is a flowchart showing a flow of control of each variable valve mechanism according to engine operating conditions.

FIG. 7 is a flowchart showing a process for setting a permission flag based on oil temperature.

FIG. 8 is a flowchart showing another embodiment.

[Explanation of symbols]

 Reference numeral 40: valve lift adjusting mechanism 45: electromagnetic switching valve 51: control unit 70: valve timing adjusting mechanism 79: electromagnetic switching valve 80: oil temperature sensor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shin Nakamura 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (56) References JP-A-63-167016 (JP, A) JP-A-5-205 5430 (JP, A) JP-A-55-148911 (JP, A) JP-A-62-45316 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 13/00 301 F01L 1/34

Claims (4)

(57) [Claims] 1. A plurality of variable valve mechanisms for continuously or stepwise changing a valve lift characteristic of an intake valve or an exhaust valve according to supply and stop of hydraulic pressure to an actuator section, and an actuator of each variable valve mechanism. A plurality of hydraulic control valves for respectively controlling the supply of hydraulic pressure to the unit, and control means for outputting a control signal to each hydraulic control valve according to the engine operating conditions,
An oil temperature detecting means for directly or indirectly detecting the lubricating oil temperature of the internal combustion engine; and, when the detected oil temperature exceeds a set temperature corresponding to the completion of the warm-up, the hydraulic control valve is used for the control means. And a hydraulic supply permitting means for outputting a signal for permitting the supply of the hydraulic pressure. A variable valve operating device for an internal combustion engine comprising: A variable valve operating device for an internal combustion engine, wherein a plurality of variable valve operating mechanisms have different set temperatures. 2. A plurality of variable valve mechanisms for continuously or stepwise changing a valve lift characteristic of an intake valve or an exhaust valve according to supply and stop of hydraulic pressure to an actuator section, and an actuator of each variable valve mechanism. A plurality of hydraulic control valves for respectively controlling the supply of hydraulic pressure to the unit, and control means for outputting a control signal to each hydraulic control valve according to the engine operating conditions,
An oil temperature detecting means for directly or indirectly detecting the lubricating oil temperature of the internal combustion engine; and, when the detected oil temperature exceeds a set temperature corresponding to the completion of the warm-up, the hydraulic control valve is used for the control means. And a hydraulic pressure switching permitting means for outputting a signal for permitting switching between supply and stop of the hydraulic pressure. A variable valve operating device for an internal combustion engine, comprising: a plurality of variable valve operating mechanisms under the same engine operating condition. A variable valve apparatus for an internal combustion engine, wherein the plurality of variable valve mechanisms that may be supplied with hydraulic pressure have different set temperatures. 3. The set temperature of a variable valve mechanism in which the valve lift characteristic changes continuously is set lower than the set temperature of the variable valve mechanism in which the valve lift characteristic changes stepwise. Item 3. The variable valve train for an internal combustion engine according to Item 1 or 2. 4. The variable valve mechanism in which the valve lift characteristic changes continuously is a valve timing adjustment mechanism that changes the phase of a camshaft with respect to a crankshaft, and the valve lift characteristic changes stepwise. 4. The variable movement of an internal combustion engine according to claim 3, wherein the variable valve mechanism is a valve lift adjusting mechanism that selectively transmits a lift of one of a low-speed cam and a high-speed cam to an intake / exhaust valve. Valve device.