JPH0326815A - Valve timing control device of dohc engine - Google Patents

Abstract

PURPOSE:To improve balance in weight and a space by a method wherein a timing control mechanism for varying opening/closing timing at low speed and high speed is mounted on one end of one of cam shafts driven by a crank shaft. CONSTITUTION:In a valve gear of a V-type six cylinder engine 1, an end of each inlet cam shaft 6 is driven by a crank shaft 25. On one end 6a of each inlet cam shaft 6, an intake timing control mechanism 8 for varying opening/ closing timing by the inlet cam shaft 6 at low speed and high speed is mounted. On the other end 6b of each inlet cam shaft 6, an exhaust timing control mechanism for varying opening/closing timing by an exhaust cam shaft 7 at low speed and high speed and a hydraulic control device 30 are mounted. Further the respective inlet cam shafts 6 and respective exhaust cam shafts 7 are connected by transmission chains 18. Thus the timing control devices 8, 9 are placed separately on both ends of the inlet cam shaft 6 so that relatively heavy weight and a space can be separately positioned on both sides thereby realizing good balance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a valve timing control i2g device for an engine, and particularly to a Dot!
Timing system when both intake timing and exhaust timing are changed in C engine? This invention relates to improving the arrangement position of the III mechanism.

[Conventional technology]

Conventional valve timing control systems for Dot{C engines have the following structure, for example. Intake camshaft.
and one end of the exhaust camshaft is simultaneously driven by the crankshaft via one transmission member, and
At one end of the intake camshaft, an intake timing control mechanism is installed that makes the opening and closing timing of the intake valve earlier at low speeds than at high speeds, and at the same time, at one end of the exhaust camshaft, the opening and closing timing of the exhaust valves is installed at low speeds and at high speeds. Slower exhaust timing system I! Some are equipped with a mechanism. [Problems to be solved by the invention] However, the above-mentioned conventional valve tying control device has the following problems:
Due to its structure, the above-mentioned intake. Each of the exhaust timing control mechanisms must be placed on the same side of the intake camshaft and exhaust camshaft, and on the side where the transmission member is provided. As a result, the side of the timing control machine, which has a relatively large installation space and a large weight, is biased to one side in the camshaft direction.
As a result, there is room for improvement in the balance of installation space and weight with this conventional device. In addition, the intake and exhaust timing control mechanisms are
Since they are installed separately on the exhaust camshafts, each camshaft must be equipped with a hydraulic control device consisting of a control valve and a solenoid.In other words, hydraulic control? 21 devices are required, which increases the cost accordingly and requires 28 locations.

In addition, when a timing control mechanism is provided, the rotating mass of the camshaft increases accordingly, so when the camshaft rotates while opening and closing the valve, the tension applied to the transmission member that drives the camshaft, such as the timing helt, fluctuates greatly. Become. In particular, when a timing control mechanism is provided for each camshaft and the camshafts are simultaneously driven by a single helt, the above-mentioned fluctuation becomes even larger, and there is a problem that the durability of the belt decreases.

The present invention has been made in view of the above-mentioned problems of the conventional art. And valve timing system for DOHC engine with good balance in terms of installation space? The object of the invention is to provide a hydraulic control '4.
'A' device requires only one string and can be placed in one location, which is advantageous in terms of cost and placement space.In addition, in the invention of item 2, there is a valve timing system that can improve the durability of the transmission member. The purpose is to provide I-equipment W. [Means for solving the problem] Therefore, the invention of item 1 provides a valve timing control device for a DOHC engine equipped with an intake camshaft and an exhaust camshaft. A first camshaft is driven by the camshaft, and a first camshaft is provided with a control mechanism at one end of the camshaft to change the opening/closing movement of the camshaft between low speed and high speed. The other end of the power camshaft drives the other end of the other camshaft, and a second camshaft is provided at the other end of the one camshaft that changes the opening/closing timing of the other camshaft between low speed and high speed. A timing control mechanism is provided, a hydraulic passage is provided on one of the camshafts for supplying hydraulic oil to both of the timing control mechanisms, and a hydraulic control device for opening and closing the passage is provided at the end of the one of the camshafts. The invention set forth in item 2 is characterized in that, in the invention set forth in item 1, one camshaft is driven by the crankshaft via the first transmission member, and the second camshaft is driven by the one camshaft through the first transmission member. It is characterized in that the other camshaft is driven via a transmission member, and a second valve timing control mechanism is attached to the other end of the other camshaft.

Here, at low speed in the present invention. High speed means when the engine speed is low or high. Also, the first and second
Transmission members include transmission belts, chains, and gears. Further, the present invention includes both a case where the intake camshaft is driven by the crankshaft and a case where the exhaust camshaft is driven by the crankshaft. When one end of the intake camshaft is driven by the crankshaft, the intake timing control mechanism must be installed at one end of the intake camshaft, and the exhaust tie control mechanism must be installed at the other end of the intake camshaft or the other end of the exhaust camshaft. becomes. In addition, when one end of the exhaust camshaft is driven by the crankshaft, the exhaust timing control mechanism is provided at one end of the exhaust camshaft, and the intake timing control mechanism is provided at the other end of the exhaust camshaft or the other end of the intake camshaft. Become. [Operation] In the present invention, one end of either the intake or exhaust camshaft is driven by the crankshaft, and the other end of the one camshaft drives the other end of the other camshaft. With this structure, the l-th timing control mechanism can be disposed at one end of the one camshaft, and the second timing control mechanism can be disposed at the other end of either of the camshafts. The second timing control mechanism can be placed separately at both ends in the camshaft direction, resulting in a better balance in terms of weight and placement space. In the invention of item 1, one end of one camshaft. /th
No. 1 at the end. A second timing control mechanism is provided, and a hydraulic passage formed in one of the camshafts so as to communicate with both timing control mechanisms is opened and closed by the hydraulic control device. A group is enough. Furthermore, in the invention of item 2, since the two timing control mechanisms are provided separately for one camshaft and the other camshaft that are interlocked via the second transmission member, the two timing control mechanisms are installed separately. The variation in load that occurs on the transmission member due to
It is distributed and applied to the first and second transmission members, respectively, and the durability of the first transmission member is improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 8 are D according to an embodiment of the invention of item 1.
o} FIG. 2 is a diagram for explaining a valve timing control device for an IC engine.

In the figure, l is a type 6 six-cylinder engine to which the present invention is applied, and the engine 1 has an oil pan 3 on the lower surface of a cylinder body 2 shaped so that six cylinders form a predetermined bank angle. Installation, a pair of cylinder heads 4 on the top surface
．． 4 are arranged and fixed with head bolts, and the upper surface of each cylinder hend 4, 4 is covered with a hend cover 5.5.

An intake port 4a to which an intake manifold is connected is formed on the inside of the hunk of the cylinder 4 to each cylinder, and an exhaust port 4b to which an exhaust manifold is connected is formed on the outside. Further, on the surfaces of the cylinder heads 4 that meet the respective head force bars 5, an intake camshaft 6 is disposed on the inside of the bank, and an exhaust camshaft 7 is disposed parallel to and rotatable on the outside of the bank.

An intake timing control mechanism 8 is attached to one end 6a of each intake camshaft 6b. This intake timing control mechanism 8 includes an inner inner shaft 1) fixed to one end 6a of the intake camshaft 6, an intake pulley l2 mounted on the outside of the shaft 1), the pulley 12, and the inner shaft 1). The slide piston 13 is inserted between the piston 11 and the slide piston 13.

A drive belt 17 serving as a first transmission member is wound between the intake pulley IJ l 2 of each of the intake camshafts 6, 6 and the drive pulley 25a of the crankshaft 25. Note that the first transmission member may be a chain or a gear, and 26 is a tension pulley.

The connection hole 1)a of the inner shaft 1) is fitted into one end 6a of the intake camshaft 6, and the locking pin 14 is inserted between the two, and the connecting bolt 15 is inserted through the waffle 15b. It is fixed to the intake camshaft 6 by screwing into one end 6a. Further, a hydraulic passage 15a is formed through the connecting bolt 15, and the passage]. One end of the inner shaft 5a communicates with a hydraulic passage 6c extending through the entire length of the intake camshaft 6, and the other end opens into a recess 1lb of the inner shaft 1). In addition, 6d is
This is a hydraulic pressure introduction passage, which communicates with a lubricating hydraulic bomb provided in the engine 1 via a hydraulic passage formed in the cylinder head 4 (not shown).

The slide piston 13 has a cylindrical shape, and is formed by connecting the main piston 13a and the sub-piston 13b with a bolt 136 and pressing the two together with a biasing spring.
is forced outward in the camshaft direction. Helical splines 13C and 13d with opposite helical directions are formed on the outer and inner circumferential surfaces of the slide piston 13, and the inner circumferential surface of the intake pulley 12 and the outer circumferential surface of the inner shaft 1), respectively. Helical spline 12 shaped like
b. It meshes with IIC. As a result, the intake timing controller fJI8 causes the slide piston 13 to
By moving the intake camshaft 6 inward in the camshaft direction using hydraulic pressure, the intake camshaft 6 is moved at a predetermined phase angle (for example, clockwise when viewed from the right side of Figure L) in the direction of advancing the opening/closing timing with respect to the intake boob 12. Rotate relatively by IO degrees.
An exhaust timing control mechanism 9 is attached to the other end 6b of the intake camshaft 6. This is done by placing a slide piston l3 on the outer periphery of the inner shaft 1), mounting a driving sprocket 19 on the outer periphery of this, and driving the helical splines on the outer and inner peripheries of the slide piston 13.
The inner circumferential surface of the inner shaft 1 and the helical spline of the outer circumferential surface of the inner shaft 1) are engaged with helical splines, and the structure is basically the same as that of the intake timing control mechanism 8 described above. However, this intake timing control mechanism 9 moves the driving shaft 19 at a predetermined phase angle (for example, 6 degrees) with respect to the intake camshaft 6 by advancing the slide piston 13 inward in the camshaft direction with hydraulic pressure. } counterclockwise when viewed from the right side in FIG. 1, that is, in a direction that delays the opening/closing timing of the exhaust camshaft 7.
Hydraulic control for 0! A control valve 2l constituting the a position 30 is installed, and a solenoid 22 for opening and closing the valve 21 is provided outside the valve 21. The control valve 21 is constructed by inserting a plunger 24 having a hydraulic pressure outlet 24a into a housing 23 having a hydraulic pressure inlet 23a so as to be able to move forward and backward and biased in the backward direction, and close when the plunger 24 is advanced. , it opens when you move it backwards. Further, the solenoid 22 is connected to the housing 22.
A coil 22b is placed in the coil 22b, and an armature rod 22c is inserted into the coil 22b. When the solenoid 22 is turned on and the coil 22b is energized, the armature rod 22C moves forward to move the plunger 24 forward and open the hydraulic passage. 6C.

Further, the drive sprocket 19 is connected to an exhaust sprocket 10 fixed to the other end of the exhaust camshaft 7 by a drive chain l8. The sprockets 19, 10, the drive chain 18, and the control valve 21 are located in a chain chamber 4C formed at the other end of the cylinder head 4. Next, the effects of this embodiment will be explained. In this embodiment, the hydraulic oil from the hydraulic pump is introduced into the hydraulic passage 6C from the hydraulic pressure introducing passage 6d of the intake camshaft 6. At this time, if the solenoid 22 is turned off, the plunger 24 of the control valve moves backward and the valve 21 opens. Therefore, the hydraulic oil flows out into the nain chamber 4C as it is, and therefore, the hydraulic oil flows out into the nain chamber 4C, and therefore, the hydraulic oil flows out into the nain chamber 4C. Hydraulic pressure does not act on any of the exhaust timing control mechanisms 9, and as a result both of the timing control mechanisms 8 and 9 are turned off. On the other hand, when the solenoid 22 is turned on, the flange 24 of the control valve 21 is turned on.
advances, the valve 21 closes, and hydraulic pressure acts on the slide pistons 13 on the sides 8 and 9 of both timing control ffj machines.

Therefore, in the intake timing control mechanism 8, the advance of the slide piston 13 causes the intake camshaft 6 to rotate 10 degrees clockwise (to advance the opening/closing timing) with respect to the intake pulley 12. Here, in this embodiment, the exhaust camshaft 7 is connected to the intake camshaft 6 by the chain 1B, so if it is left as is, it will advance by the same angle as the advance angle of the intake camshaft 6. However, as described above, the exhaust timing control ms lateral 9 causes the drive subrocket 19 to rotate counterclockwise relative to the intake camshaft 6 due to the advance of the slide piston l3, and the intake camshaft 6 advances by that amount. Reduces the influence of corners on the exhaust camshaft 7. Advance angle of the intake camshaft 6 and exhaust camshaft 7. The retard angle will be explained in more detail based on FIGS. 5 and 8. Figure 5 18+ shows the intake valve (IN). The opening angle of the exhaust valve (EX) is shown by the crank angle, and the solid line in the figure shows when each of the above timing mechanisms is off, and the dashed-dotted line shows when it is on. In addition, Fig. 5 (bl is the intake camshaft (IN).Exhaust camshaft (
The phase angle of EX) is shown as a cam angle, and the clockwise and counterclockwise arrows in the figure represent the advance angle of the opening/closing timing, respectively. Indicates a retard angle. FIG. 8 also shows each timing mechanism 8.9 mentioned above.
In the figure, both of the above-mentioned tying mechanisms 8.9 are simultaneously operated in regions A and B defined by the engine speed-load (generated torque) characteristic curve and thin lines. Turn on or off. In this example refit,
As mentioned above, the intake timing control mechanism 8. The exhaust timing control mechanism 9 is turned on at the same time. or off, and when both mechanisms 8.9 are off (area B in Figure 8), the intake valve is at 120 degrees top dead center, and the exhaust valve is 108 degrees before top dead center. The maximum opening is reached at , and the wrap angle at which both valves are open at the same time is 4 degrees. When both of the above mechanisms are on (area A in FIG. 8), the opening/closing timing of the intake valve is controlled by the intake timing control mechanism 8.
This increases the speed by 20 degrees (10 degrees in terms of the camshaft angle). On the other hand, the exhaust timing control mechanism is 12 degrees (camshaft angle is 6 degrees).
degree), the opening/closing timing of the exhaust valve will be earlier by the difference between the above 20 degrees and 12 degrees, that is, 8 degrees (4 degrees in terms of the camshaft angle). This allows the valve wrap angle to be increased from 4 degrees to 16 degrees. The opening/closing timing of the intake valve and exhaust valve is controlled by the intake timing control mechanism 8. Exhaust timing control mechanism 9
The desired timing can be achieved by appropriately setting the advance and retard amounts. For example, as shown in Figure 6, if the advance and retard amounts for both are the same (10 degrees in camshaft angle), the opening and closing timing of the intake valve will be 20 degrees in crank angle.
It is possible to keep the opening and closing timing of the exhaust valve unchanged while advancing the exhaust valve. This allows the lap angle to be increased from 4 degrees to 24 degrees. Furthermore, as shown in FIG. 7, if the retardation amount of the exhaust timing mechanism 9 is made larger than the advance amount of the intake timing device fjl8, the opening timing of the exhaust valve can be advanced by 10 degrees while advancing the opening timing of the intake valve by 20 degrees. You can also delay it. This allows the lamp negative degree to be further increased from 4 degrees to 34 degrees. As described above, in this embodiment, the intake camshaft 6 is driven by the crankshaft 25, and the exhaust camshaft 7 is driven by the intake camshaft 6, and an intake timing control device is provided at one end of the intake camshaft 6. Since the mechanism 8 is provided with the exhaust timing control mechanism 9 at the other end, the advance angle of each control mechanism can be adjusted. The opening and closing timing of the intake valve is determined by setting the retard amount. And the opening/closing timing of the exhaust valve can be set arbitrarily. And in this case,
Since the intake and exhaust timing control mechanisms 8 and 9 are placed separately on both ends of the camshaft, the relatively large weight and installation space can be divided between the two, allowing li! , and a good balance in terms of placement space.

Also, the above intake. Since the exhaust timing control mechanism 8.9 is provided at both ends of the intake camshaft 6, only one set of hydraulic control device 30 is required, which reduces cost. It is also advantageous in that it only needs to be placed in one location. Figures 9 to 1) are diagrams for explaining an embodiment of the invention of Section 2 of the present application, and the same reference numerals as in Figure 1 indicate the same or equivalent parts. In this embodiment, an exhaust timing control mechanism 9 is disposed at the other end 7b of the exhaust camshaft 7, and the drive sprocket 19 of the mechanism 9 and the intake sprocket 10 fixed to the other end of the intake camshaft 6 are different from each other. Drive chain 18 as a second transmission member
are connected.

Note that this second transmission member is a transmission belt. It can also be a gear. In this embodiment, a hydraulic control device 30 is also provided on the other end 6b side of the intake camshaft 6. The control valve 21 of the device 230 is inserted and fixed to the other end 6b, and the solenoid 22 disposed under the pressure of the control valve 21 is fixed to the chain chamber 4C of the cylinder head 4. Here, the intake and exhaust tie control machine horizontal 8.9 of this embodiment
are arranged to advance and retard the crank angle by, for example, 20 degrees, respectively.

In this embodiment, the intake and exhaust timing controllers horizontal 8.9 are set to the intake and exhaust timing controllers, respectively. Attached to one end of the exhaust camshaft 6, 7 and the other end,
Since a hydraulic control 4A position 30 is provided at the other end of each camshaft 6, 7, it is possible to simultaneously turn on or off the horizontal tie control devices 8 and 9 as in the first embodiment, and Turn on each timing system 71) mechanism 8.9 individually. Off-1
You can also do it. For example, as shown in Figure 1), both mechanisms are turned on or off in areas A and B,
In region C, the intake side can be turned off and the exhaust side can be turned on. Alternatively, as shown in Figure 1), the above region B can be divided into D and H, and in region D, the intake side is on and the exhaust side is off, and in region E, both are off. For example, if the intake side is turned off and the exhaust side is turned on (region C), as shown in Figure 10, the intake valve opening/closing timing remains the same due to the intake side being turned off, and the exhaust valve opening and closing timing is unchanged when the exhaust side is turned on. Only the opening and closing timing can be delayed by 20 degrees using the crank angle, and the wrap angle becomes 24 degrees from 4 degrees when both are off. In the figure, the solid line indicates the off state, and the dashed line indicates the on state.

Furthermore, in this embodiment, the intake timing control mechanism 8 is installed on the intake camshaft 6, and the uP timing control mechanism 3 is installed on the exhaust camshaft 7, so that the relative relationship between the camshaft and the boolean when turned on is The direction of rotation is now the same, and the amount of advance angle of both timing controllers is now the same. Since the amount of retardation is made the same, both timing control mechanisms 8 and 9 can be used in common. Furthermore, since each control mechanism is provided on a separate camshaft and connected by a transmission chain 18, the timing control mechanism 8.9
Tension fluctuations caused by the installation of the belt will be distributed to the drive belt 17 and the transmission chain 18 and act on it, and in particular, there will be no excessive load fluctuations on the drive belt 17, greatly improving the durability of the belt 17. can. In the above embodiment, as shown in FIG. 8, each timing control mechanism was turned on during low-speed rotation, but on the contrary, it may be arranged to turn on during high-speed rotation. This is advantageous in that the hydraulic pressure generated is high during high-speed rotation. In this case, of course, it is necessary to set the intake timing control mechanism to delay the opening/closing timing when it is on, and to advance the exhaust timing control mechanism when it is on. The amount and retardation angle were respectively constant, but by making the structure of the timing control mechanism and the magnitude of oil pressure variable, example-t [j 1st) Fig. (a
It is also possible to vary the amount of retardation in the subregions A and C at l. For example, in area A, the retardation amount is set as shown in figure 5 tal, and in area C, the retardation amount is set as shown in figure 10 fat. 1 (24 degrees) becomes larger, and the pulsation effect of the air can be effectively utilized in the high rotation and high load range (C, Kooshi), improving performance.

Furthermore, by adopting the retardation amount shown in FIG. 7 {δ} in region A, the ohme cooler knob amount (34 degrees) in region A becomes larger than the Ohno/Ranob position in region C, improving fuel efficiency. Further, in the above embodiment, the case where the intake camshaft 6 is driven by the crankshaft 25 has been explained, but the present invention can of course be applied to the case where the intake camshaft 6 is driven by the crankshaft. Further, in the above embodiment, a V-type engine has been described, but the present invention can of course be applied to other in-line engines.

〔Effect of the invention〕

As described above, according to the valve timing control W mechanism for a DOHC engine according to the present invention, since the intake and exhaust timing control mechanisms are arranged separately at both ends in the camshaft direction, the weight is reduced.
In addition, in the invention of item 1, each of the above-mentioned timing control mechanisms is arranged at both ends of the same camshaft, so that the hydraulic control system is not controlled. Since only one set of In'J locations is required, and therefore only one location is required, in addition to the above-mentioned effects, cost savings can be achieved. It also has an advantageous effect in terms of the number of placement locations.

[Brief explanation of drawings]

1 to 8 are diagrams for explaining a valve tying control device according to an embodiment of the invention set forth in item 1. 3 is a partially sectional plan view of the hydraulic control device, FIG. 4 is a side view of the engine in which the embodiment device is adopted, and FIG. ). Figure 6 (a), Figure 7 (al is a diagram showing opening/closing tie bending in crank angle, Figure 5 (b), Figure 6 mountain), Figure 7
Figures (bl are diagrams showing the amount of advance and retardation of the camshaft, respectively, Figure 8 (a), Figure 8 + 1) l are the engine rotation speed vs. load characteristic curves that represent the on and off regions of the timing control mechanism, respectively. 9 to 1) are diagrams for explaining an embodiment of the invention of item 2, and FIG. 9 is a partially sectional plan view with the hand cover removed, and FIG. 5) is a diagram showing the opening/closing timing in terms of crank angle, and Figure 1O fbl shows the advance angle of the camshaft. 1) A diagram showing the amount of retardation; 1) A diagram showing the engine rotation speed vs. load characteristic curve. In the figure, l is DOH
C engine, 6.7 is the intake 8 exhaust camshaft (one side, the other camshaft), 6a 6b is one end of the intake camshaft, the other end, 7
b is the other end of the exhaust camshaft, 8 is the intake timing control mechanism (
9 is an exhaust timing control mechanism (second timing control mechanism), and 25 is a crankshaft.

Claims (3)

[Claims] (1) In a valve timing control device for a DOHC engine equipped with an intake camshaft and an exhaust camshaft, one end of one of the camshafts is driven by a crankshaft, and
A first timing control mechanism is provided at one end of the one camshaft to change the opening/closing timing of the one camshaft between low speed and high speed, and the other end of the one camshaft drives the other camshaft. At the same time, a second timing control mechanism is provided at the other end of the one camshaft to change the opening/closing timing by the other camshaft between low speed and high speed, and both timing control devices are provided at the one camshaft. A valve timing control device for a DOHC engine, characterized in that a hydraulic passage for supplying hydraulic oil to the mechanism is formed, and a hydraulic control device for opening and closing the hydraulic passage is disposed at an end of the one camshaft. (2) In a valve timing control device for a DOHC engine equipped with an intake camshaft and an exhaust camshaft, one end of one of the camshafts is driven by a crankshaft via a first transmission member, and A first timing control mechanism is provided at one end of the shaft to change the opening/closing timing of the one camshaft between low speed and high speed. A second timing control mechanism that drives the other end of the camshaft and changes the opening/closing timing of the other camshaft between low speed and high speed is provided at the other end of the other camshaft. Valve timing control device for DOHC engine. (3) The one and the other camshafts are intake and exhaust camshafts, respectively, and the first timing control mechanism is configured to make the opening/closing timing of the intake camshaft earlier at low speeds than at high speeds, Claim 1 or 2, wherein the second timing control mechanism is configured to make the opening/closing timing of the exhaust camshaft the same or slower at low speeds than at high speeds. DOHC
Engine valve timing control device.