JPS6027716A - Controller of valve timing of engine - Google Patents

Abstract

PURPOSE:To obtain a favorable output property extending over the whole of operating region, by a method wherein two exhaust valves are provided on a cylinder and the total valve opening period of two suction valves is made to vary according to the operating state of an engine. CONSTITUTION:Two exhaust valves whose valve opening periods are different from each other are provided, timing of the exhaust valve (primary side exhaust valve) whose valve opening period is shorter is fixed and that of the exhaust valve (secondary side exhaust valve) whose valve opening period is longer is varied according to an operating state. In other words, the secondary side exhaust valve is set up at side (f) wherein valve opening timing is early at the time of high load operation, at side (a) wherein an overlap period becomes short at the time of low load operation and at side (e) wherein valve opening timing is delayed in a common use region. With this construction, a favorable output property is obtained extending over the whole of operating region.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve timing control device that controls the opening period of an intake valve or an exhaust valve in accordance with changes in operating conditions.

(Description of Prior Art) Generally, it is preferable to change the opening/closing timing of the intake and exhaust valves of the engine depending on the operating state of the engine. For example, in high-load engine operation, increasing the charging efficiency by increasing the valve opening period is necessary to obtain high output, but if the valve opening period is lengthened by delaying the timing of closing the intake valve, , the problem of intake air blowback occurs during high-load, low-speed operation. Additionally, the overrun period of the intake and exhaust valves has an effect on the amount of residual burnt gas in the intake air, but when the engine is operating at low load, this overrun period should be made as short as possible to reduce the amount of residual burnt gas. It is preferable to obtain combustion stability, and <
, it is possible to lower the idle rotation speed, improve fuel efficiency, and reduce unburned harmful components in the air. Considering the above circumstances, the engine valve opening timing can be varied according to the engine operating condition by 5+111f! (Adding + has been known for a long time. For example, q'3 all 3 publics t+! !; 2-3 !;
g / Publication No. 6 discloses a structure in which the meshing relationship between the timing chain and the camshaft's Sugerocket is changed so that A11l can respond to changes in operating conditions and can imitate Parbuta Iminoji. has been done. In addition, Japanese Patent Publication No. 879 (1982-3) discloses that a planetary gear oi' = 4'l'T controlled by a Chikushin carbana is interposed between the output shaft of the engine and the camshaft. discloses a structure in which a phase change is caused between an engine output shaft and a camshaft depending on the engine rotation speed.

In addition to this, there is also a known structure in which a cam whose shape changes in the axial direction is formed on the camshaft, and the 88 camshaft is moved in the axial direction according to engine thrust conditions to change the valve opening timing. It is being These conventional devices control valve timing according to changes in engine operating conditions.
However, since the control is for an engine that has seven intake and exhaust valves in one cylinder, and the purpose is simply to change the opening and closing timing of the valves, these devices are not sufficient. It is not possible to perform pulp control in response to changes in operating conditions.

(Object of the present invention) Therefore, the object of the present invention is to change the holding period of the above-mentioned exhaust valve according to the operating condition of the engine in an engine equipped with a pair of exhaust valves for one cylinder. It is an object of the present invention to provide an engine valve timing control device that can obtain preferable output characteristics over the entire operating range of a P1 engine from a low load range to a high load range.

(Configuration of the present invention) The above object of the present invention is achieved by the following configuration.

That is, the present invention provides an engine equipped with a pair of exhaust valves that open and close a pair of exhaust ports provided in one cylinder at fixed timings r9T, in which the opening timings IMJ of the pair of exhaust valves are made different, and The present invention is characterized in that a valve timing changing means is provided for changing the valve timing of the exhaust valve having a longer opening period among the pair of exhaust valves in accordance with changes in operating conditions.

The configuration of the present invention will be explained with reference to FIG.

The V type of the present invention has two J-no-1 valves with different lengths of opening period.
Valve f: Valve timing of the shorter exhaust valve 91' between the opening period and valve opening period 91'; the closing timing has been identified, and the valve timing of the exhaust valve with the longer opening period. It is designed to flare up depending on the timing or the liquefaction of the operating state. As the angle changing mechanism used in the pulse timing/fming changing means, a conventionally known mechanism can be used.

In the specific '1ltlJ control of the present invention, during high-load operation, the exhaust valve with the longer d5, the above-mentioned valve opening period 1... has a small overrun period during low-load operation, so that the 1.1 valve timing is increased. Also, when running under medium load, that is,
In the regular use area, the above valve opening JvJ is set so that the valve opening timing is
By controlling the valve timing of the exhaust valve with the longer tune fiij, it becomes possible to achieve preferable exhaust 1i control over the entire operating range of the engine.

(Effects of the present invention) According to the present invention, in an engine equipped with two exhaust valves, the valve timing of the exhaust valve which has a longer valve opening period is changed, and thereby the engine is operated. Precise control that adapts to changes in conditions becomes possible. For example, by performing the above-mentioned control specifically, under high load conditions, the valve opening timing is earlier and the exhaust valve opening period is lengthened, improving exhaust efficiency and producing high output. Obtainable. During low-load operation, the overrun period is controlled to be short, so the amount of residual burnt gas in the combustion chamber can be reduced and combustion can be stabilized. Further, in the normal use range, the fti control is performed so that the opening timing of the exhaust valve is delayed, so that the effective expansion ratio can be increased and the fuel efficiency can be improved.

Also, the exhaust valve on the opposite side of the timing is set to 1 valve period and -
11i], (Il+ is small and set to standard valve timing, so that there is no problem with timing change control.Furthermore, the intake valve whose valve timing is changed is Since the valve opening period is long and the opening area is large, effective intake fjjljsenj can be performed with a small control amount.

(Tue JJ 10 examples) Below, we will discuss embodiments of the present invention with reference to the drawings.
do.

Referring to FIG. 2, the engine 10 of this example is
1 cylinder 12k'('J' L, each cylinder 126゛(-(d/next(tli+ slow pressure to the intake passage 14+) One intake trace of the next Tsukuda intake port 20 is provided, and these ports 16 and 20 have /
? The K(III intake valve 22 and the 22X O+IL intake valve 24 are each seen in combination.

It's sweet, it's so hot. 26.28
A first exhaust valve 84 and a first exhaust valve 86 are provided, respectively.

The intake valves 22,24 are connected to the cams 4.24 formed on the camshaft 88.
It is assembled with o and cam 4.2.

The exhaust valves 84 and 86 are connected to a cam 46 formed on the camshaft 44.
．． 48 respectively. The cam 48 that operates the second exhaust valve 86 is configured such that the opening time of the second sugar exhaust valve 86 is the first.
The exhaust valve 84 has a groin shape that is longer than the opening time of the exhaust valve 84 and has a larger opening area.

The camshaft 88.44Vi is rotated by a timing belt 50 synchronized with a crankshaft (not shown).

A primary side intake passage 14 and a secondary side air reverse passage 18 are branched from an intake passage common to each cylinder, and a throttle valve is provided in the intake passage. An on-off valve 54 is provided in the secondary intake passage, and the on-off valve 54 is opened for convenience during high-load operation. A variable ta mechanism 57 is provided to change the valve timing of the second exhaust valve. The oJ mechanism 57 is connected to the rotation member 59 rotatably supported by the camshaft 44 and the rotation #1.
) A driving shaft 61 attached to the J section 59 and an operating member that operates the PjA moving shaft 61 to rotate the rotating member 59 by 1 instead of the camshaft 44 (58 and this operating member 6B 3
(in the figure) is equipped with a motor 05 that is operated on the right side. A fitting hole 59a for accommodating a tappet 67 so as to be movable therein is provided in the rotation J section wing 59. 1 of the tappet 67 cams 1 and 8 and the valve stem 24-a of the intake valve 24
Intervening at t1, the thread is pushed upward by the sliding ring 69, and when the cam +8 rotates L1, the tappet (67) comes into contact with the cam surface and is pushed down at the same time, causing the release from the cam 48. The acting force is transmitted to the valve stem 86a, and the bleed valve 86 opens and closes by kneading.

When the motor 115 is actuated, the working part 68 moves left and right, and this causes the drive shaft (11) to rotate the rotating member 59 to the side of the cam l1il 44.
When the tappet 9 rotates, the tappet 67 housed in it also moves, and the relative position 1 between the tappet 7 and the cam 48 changes.
The contact position and f position are out of alignment and the second exhaust valve 8 (position 1 + I:
ilJ time le' changes. In this example engine, the variable '+' that records the valve timing of the second intake valve on the far side? ,
"; Ii 50 was established, and the town of Machikumi Yusaku S5
6 is equipped with a rotating member 58, a drive shaft 60, an operating part 62, a motor 64, a tappet 66, and a sedge ring 68. These functions are the same as those of the variable analysis structure 57, so a description thereof will be omitted. do.

As shown in FIG. 9, motor 64, t! 5, a control device 71 preferably constituted by a microcomputer (hereinafter referred to as microcomputer) is provided. A rotation speed signal S output by a rotation speed sensor 70 that detects the engine rotation speed, and a load signal S2 outputted by a load sensor 72 that detects the engine load are input to the control device 71.

Control device 71 outputs control signals to motors 64,65. The motors 64 and 65 are reversible motors, and gears are controlled according to the above control signals. 4.75 in a predetermined direction a predetermined distance, and move the operating part 62.6B left and right to change the valve timing of the secondary intake valve 24 and the second exhaust valve 86. The positions, that is, the valve timings of the secondary intake valve 24 and the secondary exhaust valve 86 are detected by position sensors 76 and 77, and these signals are input to the control device 71. The control contents when a microcontroller is used as the control device 71 are shown in FIG. S in the form of a flowchart. The microcomputer 71 first calculates the rotation i'f R from the rotational speed signal S, and calculates the engine load P from the load signal S2. d1 rotation speed R in the RAM in the microcomma l,! : The Mazda representing the relationship between the load P and the position T of the sweeping member 62.6B is read in advance, and the corresponding sweeping member 6B is obtained from the rotation vR and engine load P calculated above. The target position T of 6B is detected. Next position sensor 76.77
No. 41 S, VC, J:,! l) Operating member 62.6
The current position [(Ps) of 8 is calculated. Then, the deviation between the target position T and the position ps is calculated. When the deviation is zero, the motor 64.65 is activated!jA I couldn't move and the control part was stolen.
12.6B does not work. When the deviation is positive, the motors 64 and 65 are driven and the sweeping member 6 is moved in accordance with the value.
2.08 is operated in the forward direction. (2) When the difference 0 is negative, the motor 64.65 is driven in accordance with the (illll:), and the operating unit 62.68 is returned by a predetermined value. Variable mechanism for the secondary intake valve 56 is independently controlled by inputting the same rotational speed signal S and load signal S2 as described above.

(Control Example) An example of control will be described with reference to FIGS. 6 and 7.

FIG. 6 shows the valve timing of the first exhaust valve 84 and the Yujitsukuda intake valve 24. At low load, the second exhaust valve 86 has a secondary timing as shown by the dotted line a. The overrun period with the valve timing (line b) of the side intake valve 24 is set to be short. Further, in FIG. 7, the valve timings of the first exhaust valve 84 and the primary side intake valve z2 are shown by lines cslid, respectively, and the opening periods and opening areas of these valves 84 and 22 are shown. is smaller than the first exhaust valve 84 and the second intake valve on the downstream side, and the valve timing is delayed to match the opening timing of the second exhaust valve at low loads. The overlapping distance [υ] is set constant so that the distance is small.

Therefore, at low load, the overrun IH of the intake and exhaust valves becomes smaller as a whole, and the amount of residual burnt gas in the combustion chamber can be reduced, thereby stabilizing the furnace firing. can. In the medium load region, that is, in the tiger region, the valve timing of the second exhaust valve 86 is set to the delayed side, as shown by Aya e, compared to the low load state shown by line a in FIG. 6. As a result, the opening timing of the exhaust valve as a whole is 1\<'f! By increasing the effective expansion ratio, combustion can be improved. In addition, in a high-load town, the low-load engine time indicated by line a also advances as shown by line f (set to lit. As a result, the opening timing of the exhaust valve is advanced as a whole, and Since the period becomes longer, exhaust efficiency improves and high output is obtained.In this case, the valve timing of the secondary side intake valve 24 is set to be delayed as shown by line g at high rotation speed. Efficiency can be improved at the same time, and even higher output can be obtained.The valve timing change control in this example is performed for the valve with the larger opening between 15ti and 4f and rule j. - Effective control can be performed with a small control amount.

[Brief explanation of the drawing]

Figure 1 is a claim correspondence diagram of the present invention, and Figure 2 is a diagram of the claims of the present invention.
A partial plan sectional view of the engine according to the embodiment, FIG.
FIG. 1I is an explanatory diagram of the system for operating the variable mechanism, FIG. 5 is a 70-chart showing an example of valve timing control of the present invention, and FIG.
FIG. 7 is an explanatory diagram showing the valve timing of the secondary side intake valve and the second exhaust valve. FIG. 7 is an explanatory diagram showing the valve timing of the t secondary side intake valve and the first exhaust valve. Explanation of symbols 10...Engine, 12...Cylinder, 22...
Primary side intake valve, 24... Secondary side intake valve, 84... First exhaust valve, 86... Second exhaust valve, 88.44... Camshaft, 40.4L 46.48. ...Cam, 50...
Timing belt, 58.59... circuit layer 1 part phase, 64
．． 65...Motor, 66.67...Tappet. Patent applicant: Raiin Kogyo Co., Ltd. Figure 1 Figure 3 24:jb

Claims (1)

[Claims] In an engine equipped with a pair of exhaust valves that open and close a pair of exhaust ports provided in one cylinder at predetermined timings, the opening periods of the pair of exhaust valves are different, and the opening period of the pair of exhaust valves is different. A valve timing control device for an engine, characterized in that a valve timing control device is provided for changing the valve timing of an exhaust valve having a longer valve period in accordance with the convenience of operating conditions.