JP2004225600A - Variable valve system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain an increase in oil drain amount due to oil leakage into an ignition advance chamber from an ignition delay chamber in performing ignition delay control by supplying hydraulic oil to the ignition delay chamber (an ignition delay chamber port a) from a hydraulic port c with a flow path switching valve 12 to drain hydraulic oil into a drain port e from the ignition delay chamber (an ignition advance chamber port b) at the time of high engine speed. <P>SOLUTION: An ignition delay value is set at 1° at the time of the high engine speed, based on which the flow path switching valve 12 is controlled, thus reducing the flow passage area of the drain port e. Otherwise, a closing valve for closing the drain port e is provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable valve operating device for an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art As a conventional variable valve operating device for an internal combustion engine, a member (vane) for changing the operating characteristics (opening / closing timing) of an intake valve or an exhaust valve in accordance with an operating position, and provided on both sides of the member separated by the member. First and second hydraulic chambers for driving the member by a pressure difference (a retard chamber and an advance chamber for driving the member in a retard direction and an advance direction, respectively, by an internal pressure); and the first and second hydraulic pressures A valve (a retarding chamber and an advancing chamber) and a flow path switching valve for controlling a connection state between a hydraulic supply passage and a drain passage, and variably control an operation characteristic (opening / closing timing) of an intake valve or an exhaust valve. (See Patent Document 1).
[0003]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-345870
[Problems to be solved by the invention]
By the way, when it is not necessary to change the operation characteristics (opening / closing timing) of the intake valve or the exhaust valve and keep the reference state (the most retarded position), the flow path switching valve is set to the non-energized state (duty 0%) The hydraulic pressure is supplied to the first hydraulic chamber (retard chamber), and the hydraulic pressure is drained from the second hydraulic chamber (advance chamber).
[0005]
At this time, since the pressure difference between the first hydraulic chamber (retard chamber) and the second hydraulic chamber (advance chamber) is maximized, the oil supplied to the first hydraulic chamber (retard chamber) The fluid leaks toward the second hydraulic chamber (advanced chamber) through the clearance between the housing and the vane, and is drained into the cylinder head through the drain passage opened by the flow path switching valve. At this time, since there is nothing to restrain the leaked oil, the amount of leakage becomes extremely large, and becomes larger at high engine speed.
[0006]
Therefore, due to the oil leakage, there is a problem that an extra oil needs to be supplied, resulting in an increase in the size of the oil pump and an insufficient amount of oil supply to other sliding portions.
[0007]
An object of the present invention is to solve such a problem.
[0008]
[Means for Solving the Problems]
For this reason, in the present invention, under predetermined conditions, the passage area of the drain passage is reduced to such an extent that a change in the operating characteristics of the intake valve or the exhaust valve does not affect the combustion state of the engine.
[0009]
【The invention's effect】
According to the present invention, even if oil leaks from the first hydraulic chamber to the second hydraulic chamber, the leaked oil is not drained as it is. It is possible to improve the pump capacity and reduce the pump capacity.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram of a variable valve device of an internal combustion engine (engine) showing one embodiment of the present invention, and FIG.
[0011]
This variable valve device changes the phase between the camshaft driving sprocket 1 and the camshaft 2 to change the opening / closing timing of the intake valve. For this purpose, a housing 3 and a vane 4 having three to four blades rotatable in the housing 3 are provided, and a sprocket 1 for driving a camshaft 1 is attached to an end face of the housing 3 by bolts 5. The end of the camshaft 2 is connected to the end face of the camshaft 4 by a connecting pin 6.
[0012]
Accordingly, the phase of the camshaft 2 with respect to the camshaft driving sprocket 1 (crankshaft) can be changed by the relative rotation position of the vane 4 with respect to the housing 3, thereby changing the opening / closing timing of the intake valve. Can be. Assuming that the state of FIG. 2A is the reference state and the most retarded position of the intake valve opening / closing timing (opening timing and closing timing) is, the state of FIG. It is changed to the most advanced position.
[0013]
Here, in the moving space of each blade of the vane 4 in the housing 3, a first hydraulic pressure is applied to the vane 4 in a direction of returning the intake valve opening / closing timing to the reference state (most retarded position) with each blade interposed therebetween. A hydraulic chamber (hereinafter referred to as a retard chamber) 7 and a second hydraulic chamber (hereinafter referred to as an advanced chamber) 8 for applying a hydraulic pressure to the vane 4 in a direction to change the intake valve opening / closing timing to an advanced side are provided. .
[0014]
An oil passage 9 is connected to the retard chamber 7, and the oil passage 9 is connected to one of the flow path switching valves 12 through a cylindrical portion of the vane 4, a support body 11 rotatably disposed therein, and the like. Port (retard chamber port) a.
[0015]
An oil passage 10 is connected to the advancing chamber 8. The oil passage 10 is connected to a cylindrical portion of the vane 4, a support 11 disposed in the inside of the vane 4 so as to be relatively rotatable, and the like. Port (advance chamber port) b.
[0016]
FIGS. 3A and 3B are cross-sectional views of the flow path switching valve 12 for different operating states. FIG. 3A is a non-energized state (duty 0%) for controlling a reference state (most retarded position), and FIG. This is the time of the maximum energization state (duty 100%) for controlling to the maximum state (most advanced position).
[0017]
The flow path switching valve 12 communicates with the valve housing 13 with a retard chamber port a communicating with the retard chamber 7 (retard chamber side oil passage 9) and with the advance chamber 8 (advance chamber chamber oil passage 10). In addition to the advance chamber port b, a hydraulic port c connected to a hydraulic supply passage (oil pump discharge side), and two drain ports d and e connected to a drain passage are provided. The retard chamber port a, the hydraulic port c, the advance chamber port b, and the drain port e are arranged in this order.
[0018]
The spool valve shaft 14 in the housing 13 is formed with three valve bodies v1 to v3, which open and close the ports a to e.
The spool valve shaft 14 is urged by a return spring 15 and is driven in the axial direction by a solenoid 16 against the urging force, and duty control of energization to the solenoid 16 is performed. Thus, the axial position of the spool valve shaft 14 can be controlled.
[0019]
Here, when the solenoid is de-energized (duty 0%), the spool valve shaft 14 moves to the rightmost in the figure by the return spring 15 as shown in FIG. And the retarding chamber port a, and the advancing chamber port b and the drain port e. As a result, as shown in FIG. 2A, the hydraulic pressure is supplied to the retard chamber 7 and the hydraulic pressure is drained from the advance chamber 8, so that the intake valve opening / closing timing is in the reference state (most retarded position).
[0020]
On the other hand, by increasing the duty to the solenoid 16 to maximize the duty (for example, 100%), the spool valve shaft 14 is moved by the electromagnetic force of the solenoid 16 as shown in FIG. By moving to the leftmost side, the hydraulic port c and the advance chamber port b communicate with each other, and the retard chamber port a and the drain port d communicate with each other. As a result, as shown in FIG. 2B, the hydraulic pressure is supplied to the advance chamber 8 and the hydraulic pressure is drained from the retard chamber 7, so that the opening and closing timing of the intake valve changes to the maximum change amount state (most advanced position). Become.
[0021]
Therefore, the intake valve opening / closing timing can be arbitrarily controlled by variably controlling the duty according to the change angle (advance angle value) of the intake valve opening / closing timing required from the engine operating state.
[0022]
By the way, in such a variable valve operating device, in the region where the engine speed is high, it is not necessary to change the intake valve opening / closing timing to the advance side, so that the flow path switching valve 12 is set in the non-energized state shown in FIG. 2 (A), the hydraulic pressure is supplied to the retard chamber 7, and the hydraulic pressure is drained from the advance chamber 8.
[0023]
At this time, since the pressure difference between the retard chamber 7 and the advance chamber 8 becomes maximum, the oil supplied to the retard chamber 7 passes through the clearance between the housing 3 and the vane 4 and the like, and the oil is supplied to the advance chamber 8. Is drained into the cylinder head by the drain port e opened by the flow path switching valve 12.
[0024]
Therefore, due to such oil leakage, it is necessary to supply extra oil, which results in an increase in the size of the oil pump and an insufficient amount of oil supply to other sliding parts.
Therefore, in the present invention, under a predetermined condition (at a predetermined high rotation speed), the drain passage (drain port e) is set to such an extent that a change in the operating characteristic (opening / closing timing) of the intake valve does not affect the combustion state of the engine. The oil passage is reduced by reducing the passage area.
[0025]
Specifically, under a predetermined condition (at a predetermined high rotation speed), an advance value (for example, 1 °) smaller than a minimum advance value (for example, 4 °) that changes the combustion state of the engine is set. The duty of the flow path switching valve 12 is controlled to advance the angle.
[0026]
FIG. 4 shows a state in which the advance value is set to 1 ° and the flow path switching valve 12 is driven at an extremely low duty. In this state, the spool valve shaft 14 of the flow path switching valve 12 moves slightly to the left with respect to the state of FIG. 3 (A) and is stabilized, and the hydraulic port c and the retard chamber port a communicate with each other to advance. Although the chamber port b and the drain port e communicate with each other, the passage areas of the hydraulic port c and the drain port e are reduced as compared with the state shown in FIG.
[0027]
For this reason, even if oil is supplied to the retard chamber 7 and oil leaks from the retard chamber 7 to the advance chamber 8, the leaked oil from the advance chamber 8 reduces the passage area of the drain port e. As a result, the oil is not drained as it is, and as a result, the hydraulic pressure in the advance chamber 8 rises, so that the pressure difference between the retard chamber 7 and the retard chamber 7 decreases, and oil leakage from the retard chamber 7 to the advance chamber 8 decreases. I do. Therefore, unnecessary work of unnecessary supply of oil is not required, and the lubrication performance can be improved and the pump capacity can be reduced.
[0028]
FIG. 5 shows the result of measuring the oil gallery pressure with respect to the engine speed when the lead angle value is 0 ° and the lead angle value is 1 °. The lead angle value of 1 ° can reduce the oil drain amount. It shows that the lubrication performance can be improved by increasing the oil gallery pressure by about 10%.
[0029]
FIG. 6 is a flowchart executed by the control unit 17 in FIG. 1 when such control is performed.
In S1, the engine speed Ne detected by the crank angle sensor, the intake air amount Qa detected by the air flow meter, the water temperature Tw detected by the water temperature sensor, and an idle switch signal are read.
[0030]
In S2, the basic fuel injection amount Tp used as a parameter representing the engine load is calculated from the intake air amount Qa and the engine speed Ne as in the following equation.
Tp = K · Qa / Ne where K is a constant.
[0031]
In S3, it is determined whether or not the vehicle is in an idle state (idle switch ON) based on the idle switch signal. In S4, it is determined whether the water temperature Tw is lower than a predetermined value Tw1 (for example, 15 ° C.). If the result of these determinations is that the engine is in the idle state or the water temperature is low, the process proceeds to S5.
[0032]
In S5, the required advance value = 0 °, the flow switching valve 12 is de-energized, and the intake valve opening / closing timing is held in the reference state (most retarded position). At this time, since the engine speed is low (idle) or the water temperature is low, oil leakage does not matter.
[0033]
If it is not in the idle state and the water temperature Tw is equal to or higher than the predetermined value Tw1 (for example, 15 ° C.), the process proceeds to S6.
In S6, it is determined whether or not the engine speed Ne is equal to or more than a predetermined value Ne8 (for example, 5600 rpm). If NO, the process proceeds to S7, and if YES, the process proceeds to S8.
[0034]
In S7, a required advance value is set with reference to a map, using the engine speed Ne and the basic fuel injection amount Tp as parameters of the engine operating state.
On the other hand, S8 is a case where the engine speed Ne is equal to or more than a predetermined value Ne8 (for example, 5600 rpm), and the original required advance value is 0 °, but here, the minimum advance angle that changes the combustion state of the engine is used. The required advance value is set to 1 ° as an advance value smaller than the value (for example, 4 °).
[0035]
After S7 or S8, the process proceeds to S9.
In S9, the cam angle sensor 18 in FIG. 1 detects an actual advance angle value.
In S10, the required advance value and the actual advance value are compared, and the duty to the flow path switching valve 12 is set and output by feedback control.
[0036]
FIG. 7 illustrates map data of the required advance value. It should be noted here that the required advance value is set to 1 ° in a high rotation region where the engine rotation speed is Ne8 (for example, 5600 rpm) or higher. Note that A12 to A68 in FIG. 7 are set to advance values equal to or greater than the minimum advance value (for example, 4 °) that changes the combustion state of the engine.
[0037]
According to this embodiment, at the time of a predetermined high rotation, the retarding chamber 7 and the hydraulic pressure supply passage (hydraulic port c) are connected by the flow path switching valve 12, and the advanced angle chamber 8 and the drain passage (drain port e) are connected. ), And the flow path switching valve 12 is duty-controlled to advance the angle so that the advance value is smaller than the minimum advance value (for example, 1 °) that changes the combustion state of the engine. Since the passage area of the drain passage (drain port e) is reduced, the amount of oil drain can be reduced and the oil pressure can be secured without adding a special control logic.
[0038]
Also, when the lubrication conditions are severe such as at high revolutions, the amount of oil drain can be reduced to ensure lubrication performance and improve seizure resistance.On the other hand, when the lubrication conditions are not severe, the work volume of the oil pump can be reduced. The output can be reduced and the output can be improved.
[0039]
Next, another embodiment of the present invention will be described with reference to FIG.
In the present embodiment, a closing valve 20 capable of closing the drain passage (drain port e) is provided in the drain passage (drain port e). The closing valve 20 is normally opened and closed instead of setting the advance value to 1 ° in the above-described embodiment.
[0040]
That is, under a predetermined condition (at a predetermined high rotation speed), the retarding chamber 7 and the hydraulic supply passage (the hydraulic port c) are connected by the flow path switching valve 12, and the advance chamber 8 and the drain passage (the drain port) are connected. e), the drain valve (drain port e) is closed by the shut-off valve 20 to reduce the passage area of the drain channel (drain port e).
[0041]
Although the addition of the shutoff valve 20 increases the cost, the oil drain amount can be more reliably set to zero.
[Brief description of the drawings]
FIG. 1 is a system diagram of a variable valve operating device showing an embodiment of the present invention. FIG. 2 is a cross-sectional view of a main part according to an operating state in FIG. 1. FIG. FIG. 4 is a cross-sectional view of the flow path switching valve when the advance value is 1 °. FIG. 5 is a diagram showing an effect of increasing the oil gallery pressure. FIG. 6 is a control flowchart. FIG. FIG. 8 is a diagram showing another embodiment.
DESCRIPTION OF SYMBOLS 1 Camshaft driving sprocket 2 Camshaft 3 Housing 4 Vane 7 Retardation chamber (first hydraulic chamber)
8 Advance chamber (second hydraulic chamber)
9 retard chamber side oil passage 10 advance chamber side oil passage 12 flow path switching valve 14 spool valve shaft 16 solenoid 17 control unit 18 cam angle sensor 20 drain passage closing valve

Claims (5)

A member for changing the operating characteristics of the intake valve or the exhaust valve in accordance with the operating position, first and second hydraulic chambers partitioned by the member and provided on both sides of the member for driving the member by a pressure difference; A variable valve apparatus for an internal combustion engine that includes a flow path switching valve that controls a connection state between the first and second hydraulic chambers, a hydraulic supply passage, and a drain passage, and that variably controls operating characteristics of an intake valve or an exhaust valve. ,
A variable valve actuation device for an internal combustion engine, characterized in that a passage area of a drain passage is reduced so that a change in operating characteristics of an intake valve or an exhaust valve does not affect a combustion state of the engine under predetermined conditions. A member for changing the opening / closing timing of an intake valve or an exhaust valve in accordance with an operating position; and a member partitioned by the member and provided on both sides of the member to drive the member in a retard direction and an advance direction by internal pressure, respectively. A retard chamber and an advance chamber, and a flow path switching valve that controls a connection state between the retard chamber and the advance chamber and the hydraulic supply passage and the drain passage, and the opening / closing timing of the intake valve or the exhaust valve is variable. In the variable valve device of the internal combustion engine to be controlled,
Under predetermined conditions, the flow passage switching valve connects the retard chamber to the hydraulic supply passage, connects the advance chamber to the drain passage, and changes in the opening / closing timing of the intake valve or the exhaust valve cause the combustion of the engine to change. A variable valve train for an internal combustion engine, wherein a passage area of a drain passage is reduced to such an extent that a state is not affected. 3. The variable valve train for an internal combustion engine according to claim 1, wherein the predetermined condition is a predetermined high rotation speed. The means for reducing the passage area of the drain passage is a means for performing duty control on the flow path switching valve to advance the flow passage switching valve so as to have an advance value smaller than a minimum advance value for changing the combustion state of the engine. The variable valve train for an internal combustion engine according to any one of claims 1 to 3, wherein The variable valve operating device for an internal combustion engine according to any one of claims 1 to 3, wherein the means for reducing the passage area of the drain passage is a closing valve that closes the drain passage.

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