JPS60159321A - Valve operation stopping device of valve operating system of engine - Google Patents

Abstract

PURPOSE:To provide easy and sure switching from valve operation to stopping and vice versa using a simple construction by furnishing a clutch mechanism which shall shut the cam shaft driving force transmitted from a cam shaft drive mechanism, to rotate the cam shaft, over to the cam shaft. CONSTITUTION:In a series type multi-cylinder engine in which the two suction valves 3P, 3S per cylinder are arranged across the corresponding two exhaust valves 4P, 4S with an ignition plug 2 each interposed, the cam shaft 8 of the valve operating mechanism to operate the secondary side suction and exhaust valve 3S, 4S is fitted with a cam sprocket 12 in its middle part, wherein the cam shaft 8 is divided into two portions at this sprocket fitting part. These two cam shaft portions 8A, 8B are borne by each other by fitting a pivot part 26b formed at one of them in a receipt part 26a formed in the other. Between the flanges provided at the ends of said cam shaft portions facing each other, a cam sprocket 12 is interposed which is equipped with a clutch C to shut the coupled condition by means of supply of pressure oil to a hole 25.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine valve system, and more particularly to a valve operation stop device for an engine valve system for activating or stopping the valve.

Conventionally, a compound intake type engine (I) is equipped with a primary intake valve that operates in the entire engine speed range, and a secondary intake valve that stops operating in the low engine speed range and starts operating in the high engine speed range ( Various types of cylinder engines have been developed, including CIS engines) and cylinder engines that can temporarily stop the operation of intake and exhaust valves for a specific cylinder to put the cylinder into a cylinder state.

In such a CIS engine or a cylinder engine, a valve actuation stop device is required to actuate or stop the valves of the engine valve system.

The present invention was created under these circumstances, and provides a valve operation stop device for an engine valve system that has a simple configuration and can easily and reliably switch between valve operation and valve stop. The purpose is to

For this reason, the valve operation stop device for an engine valve train of the present invention has a valve lift cam attached thereto to open and close the valve in the engine valve train, and a cam shaft that rotationally drives the cam shaft. The present invention is characterized in that it is provided with a clutch mechanism that connects and disconnects the camshaft driving force from the camshaft drive mechanism to the camshaft in order to control the operation and stop of the valve.

Hereinafter, a valve operation stop device for an engine valve train as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a schematic diagram showing the valve arrangement thereof, and Fig. 2 is a diagram schematically showing its schematic configuration. , Figures 3 and 4 are graphs for explaining their actions, Figures 5 and 6 are schematic diagrams showing other examples of the clutch mechanism, and Figure 7 is a schematic diagram showing other examples of valve arrangement. It is a diagram.

In this embodiment, two intake valves and two exhaust valves are provided for each cylinder of four cylinders arranged in series in the longitudinal direction, and these intake valves and exhaust valves are opened and closed by separate camshafts. DOHC (Double 0ver Head C)
An in-line four-cylinder engine with a aai) type valve train will be explained. As shown in Fig. 1, this engine has a primary intake system jNp leading to cylinder 1 and a primary exhaust system E.
Xp and 2*Intake system INs and secondary exhaust system EXs
Furthermore, as shown in Figures 1 and 2, the primary intake system IN and primary exhaust system EXp are equipped with 1* intake valve 3P and primary exhaust valve 4P that operate over the entire engine rotation range. In addition, the secondary intake system INs and the secondary exhaust system EXs are equipped with a secondary intake valve 3S and a 12th exhaust valve 4S, respectively, which stop operating in the low engine speed range and start operating in the high engine speed range. Prepared.

Here, a swirl boat is formed in the primary intake system INp.

In this example, the valve arrangement of each cylinder is 1st and 2nd.
As shown in the figure, the intake and exhaust valves are arranged so as to cross each other with the spark plug 2 in between, and the primary intake valve 3P and secondary exhaust valve 4S are connected to the engine as shown by arrow F in Figure 1.2. It is located on the 70 nt side.

Further, as shown in Fig. 12, a pair of camshafts 5.8 are disposed on the left and right sides of the cylinder head, and the camshafts 5;
Both ends of the cylinder 8 are rotatably supported by the cylinder head via bearings 13, 14; 15, 16, respectively.

Furthermore, a cam 6 for the primary intake valve 3P and a cam 7 for the primary exhaust valve 4P are mounted on the camshaft 5 for each cylinder, and the camshaft 8 is equipped with a cam 6 for the primary intake valve 3P and a cam 7 for the primary exhaust valve 4P for each cylinder. Cam 9 for the secondary intake valve 3S and cam 1 for the secondary exhaust valve 4S
0 is attached.

Here, the valve timing of cam 6.7 is of the low speed type, and the valve timing of cam 9.10 is of the high speed type.

Furthermore, a camshaft drive mechanism M that rotationally drives each camshaft 5, 8 is provided. That is, a cam sprocket (which may be a gear) 11 is located at the middle of the camshaft 5, and a cam sprocket (which may be a gear) 12 is located at the middle R of the cam shaft 8. The cam sprockets 11, 12 are both rotatably driven by a timing belt (which may also be a timing chain) driven by the crankshaft.

By the way, a clutch mechanism C is provided that connects the cam shaft driving force from the camshaft drive mechanism M to the camshafts 5 and 8.

That is, the camshaft 8 is composed of camshaft parts 8A and 8B that are divided into two parts at the cam sprocket mounting part, and a cam sprocket 12 is interposed between these camshaft parts 8A and 8B. 6 To be more specific, both of the camshaft portions 8'A and 8B have runno portions on their opposing portions (hereinafter referred to as "opposing portions"), and a cam sprocket is provided on the opposing portion of one camshaft portion 8A. 12 shaft hole 2
A shaft portion 26 that penetrates through the shaft portion 7 and pivotally supports the cam sprocket 12.
a is provided in a protruding manner, and a recessed portion 26b for supporting the end of the shaft portion 26a is formed in the opposing portion of the other camshaft portion 8B.

A return spring 28 is loaded in the four parts 26b to urge the detail 26a outward from the recess 26b in a direction τj.

Further, the cam sprocket 12 has, for example, three thin holes 25 with unequal pitches passing through it, and claws 23 and 24 that can fit into these holes 25 with unequal pitches.
Three protrusions are provided on each of the seven run portions of the camshaft portions 8A and 8B.

The hole 25 of the cam sprocket 12 has an oil passage 29 with an electromagnetic on-off valve 29a. Oil passage 30 in the annular connecting passage 29' and the ram detail 8B. Pressure oil is supplied through the annular connection path 31 and an oil path 31' in the cam sprocket 12.

Therefore, when pressure oil is supplied into the cam sprocket hole 25, the camshaft portion 8A with the pawl 23 and the camshaft portion 8B with the pawl 24 are pushed forward and backward, respectively, so that the winter melon 23. '24 can be removed from the hole 25 of the cam sprocket 12. As a result, the camshaft driving force transmitted to each camshaft portion 8A, 8B through the cam sprocket 12 is cut off.

Further, the shaft ends of each camshaft portion 8A, 8B are supported by bearing portions 15°16. ．． 16 is formed with oil chambers 17 and 18 that are partitioned by the shaft end surfaces of each camshaft portion, and each oil chamber 17:1B is equipped with an electromagnetic on-off valve 21, 21'; 22, 22'. Oil line 19.19'
;20°20″ is connected.

Therefore, when pressure oil is supplied to each oil chamber 17, 1B, each camshaft portion 8A, 8B is driven closer to each other, and since the winter melon 23, 24 engages with the cam sprocket hole 25, the cam sprocket Since the camshaft driving force from 12 is transmitted to the camshaft portions 8A and 8B, the camshaft 8 rotates.

The camshaft portion 8Al: is for the 11th and 2nd cylinders, and the camshaft portion 8B is for @3J4 cylinders.

With the above-mentioned configuration, the pawls 23 and 24 are in contact with the cam sprocket hole 2 in the low engine speed range as shown by the symbol P in FIG.
5, the camshaft 8 due to this does not rotate, and the camshaft 8 does not rotate.
When the operation of the secondary intake valve 3S and 2*exhaust valve 4S is stopped, the camshaft 5 is rotationally driven, so the primary intake valve 3P and the primary exhaust valve 4P open and close at the required low speed timing. being driven.

In this way, in the low engine speed range, only the camshaft 5 that opens and closes the 1st intake valve 3P and the 11th exhaust valve 4P is driven, so the speed at which fresh air flows into the cylinder 1 is increased and the speed is increased. It becomes possible to generate whirl and perform stable combustion. Furthermore, since the valves can be opened and closed with low-speed valve timing, volumetric efficiency can be improved and high torque can be obtained.

By the way, when the engine reaches a high speed range as shown by the symbol P+S in FIG.
Pressure oil is supplied to 8. As a result, each camshaft portion 8A.

8B is driven toward the cam sprocket 12 side, and the winter melon 23° 24 engages with the cam sprocket hole 25, so the crankshaft
In this state, the camshaft driving force from the cam sprocket throat 12 is transmitted to the camshaft 8 side.

As a result, the camshaft 8 begins to rotate, so 2*, the intake valve 3
S and the secondary exhaust valve 4S start opening/closing operations. At this time, since the tocam l1l15 is still rotating, the primary intake valve 3P and the primary exhaust valve 4P are also driven to open and close ν).

In this way, all four valves for each cylinder are driven to open and close in the high engine speed range (1), so the intake valve opening time area can be increased. Since the valve can be opened and closed in the same way, it is possible to improve volumetric efficiency and obtain high torque and high output.

Further, in order to disengage the clutch again and stop the rotation of the camshaft 8, it is sufficient to drain oil from the oil chambers 17 and 18 and supply pressure oil to the camshaft hole 25. As a result, the pawls 23 and 24 are pushed out, resulting in a clutch disengaged state.

Note that when the clutch is disengaged, the on-off valve 29a is closed and the supply of pressure oil to the cam sprocket hole 25 is stopped. In this manner, the force of the return spring 28 causes the camshaft portions 8A, 8B to remain disengaged from the cam sprocket 12.

As a result, the secondary intake valve 3S and the secondary exhaust valve 4S are again
operation can be stopped.

Note that even in this case, the 1*intake valve 3P and the 1*exhaust valve 4P continue to operate.

As described above, the engine having the present device can achieve high torque over a wide range of engine speeds, as shown by the symbol a in FIG.

For reference, the conventional valve stop is performed)D.

Figure 4 shows the leakage characteristics of an engine with a 1-I C type valve system, and shows that the conventional valve stop is not performed.
The torque characteristics of an engine having the dCam) type +yJH system are indicated by the symbol C in FIG. Even when these characteristics b+c and characteristic a are compared, it can be seen that the engine according to the present invention can generate high torque over a wide range.

Furthermore, switching between activation and deactivation of the secondary intake valve 3S and the 2*exhaust valve 4S can be easily and reliably performed.

By the way, as a means for connecting the camshaft 8 and the cam sprocket 12, other means as shown in FIGS. 5 and 6 may be used. In the systems shown in Figures 5 and 6, the camshaft 8 is driven by independent hydraulic actuators AI and A2, but in the system shown in Figure 5, the camshaft 8 rotates relative to the actuator A1. so that the rod tip 33 of the piston 34 fits into the engagement hole 32 on the end surface of the camshaft.
In the one shown in FIG. 6, the camshaft 8 is loosely fitted to the actuator A2 so that it can rotate relative to the actuator A2.
The rod tip of the piston 46 is in sliding contact with the camshaft end surface.

In addition, the reference numeral 35 in Fig. 5 is the cylinder part, 36.37 is the oil chamber, 3B, 39.40.41 is the oil passage, 42.43,
Reference numerals 44 and 45 indicate electromagnetic on-off valves, numeral 47 in Fig. 6 is the cylinder part, 48 is the oil chamber, 49 and 50 are the oil passages,
Reference numerals 51 and 52 indicate electromagnetic on-off valves.

Further, in the case shown in FIG. 5, in addition to the coupling between the camshaft 8 and the cam sprocket 12, the coupling can also be released. That is, when pressure oil is supplied to the oil chamber 36, the camshaft 8 can be pushed in the direction of the arrow α to bring the clutch into contact, and when pressure oil is supplied to the oil chamber 37, the camshaft 8 can be pulled in the direction of the arrow β. This allows the clutch to be disengaged. Therefore, when a mechanism as shown in Fig. 5 is used, the latch mechanism C as shown in Fig. 2 is unnecessary, but when a t* groove as shown in Fig. 6 is used, as shown in Fig. 2 A clutch disengagement mechanism is necessary.

When considering the occurrence of swirl, it is possible to obtain a strong swirl by arranging the valves in this embodiment (see Figures 1 and 2), and it is also possible to significantly reduce the diameter of the valves. , the primary exhaust system E with the primary exhaust valve as shown in Figure 7.
Xp and a secondary exhaust system EXs with a secondary exhaust valve are arranged on the front side of the engine, and a primary intake system INp with a primary intake valve and a secondary intake system INs without a secondary intake valve are placed on the rear side of the engine. May be placed. In this way, although the swirl is weakened, the flow coefficient of the valve is improved, so that either of the above valve arrangements can be adopted.

In addition, this device can be applied to valve control of a 5OHC type engine valve system, and can also be applied to a cylinder engine.

As described in detail above, according to the valve operation stop device for an engine valve train of the present invention, in the engine valve train, a camshaft on which a valve lift cam is attached and a cam shaft mounted with a valve lift cam to open and close a valve are used. A simple mechanism that includes a camshaft drive mechanism that rotationally drives the shaft, and a clutch mechanism that connects the camshaft driving force from the camshaft drive mechanism to the camshaft in order to control the operation and stop of the valve. This configuration not only improves combustion and torque in the low engine speed range, but also increases output in the high engine speed range, and allows for easy and reliable switching between valve operation and valve stop. It has the advantage of

[Brief explanation of the drawing]

The figures show a valve operation stop device for an engine valve train system as an embodiment of the present invention; FIG. 1 is a schematic diagram showing its valve arrangement; FIG. 2 is a diagram schematically showing its schematic configuration; 3rd, 4th
The figures are all graphs to explain the action.
6 is a schematic diagram showing another example of the clutch mechanism, and FIG. 7 is a schematic diagram showing another example of valve arrangement. 1...Cylinder, 2...Spark plug, 3P...Primary intake valve,
3S: Secondary intake valve, 4P: 4th exhaust valve, 4s: Secondary exhaust valve, 5: Camshaft, 6, 7: Cam, 8: Camshaft, 8A, 8B: Camshaft part ,9,1o...cam,11
．． 12. Fist cam sprocket, 13-16. Bearing section, 17.18--Oil chamber, 19.19', 20°20'
・・Oil passage, 21.21′, 22.22′・・Opening/closing valve, 23.24・・Claw, 25・・Cam sprocket hole,
26a...Shaft portion, 26b--Concave portion, 27...Shaft hole, 28
...Return spring, 29...Oil passage, 29'...
Annular connection path, 29a...opening/closing valve, 3o...oil path, 31...
・Annular connection path, 31' ・・Oil path, 32 ・・Engagement hole, 3
3...Rod tip, 34...Piston, 35...Cylinder part, 36.37...Oil chamber, 38-41...Oil passage, 4
2-45...Opening/closing valve, 46...Piston, 47...Silling part, 48...Oil chamber, 49.50...Oil passage, 51.5
2...Opening/closing valve, C...clutch mechanism, M...camshaft drive mechanism, Ai, A2...actuator, EXp...primary exhaust system, EXs...secondary exhaust system, INp...primary intake system , INs...Secondary intake system. Agent Patent Attorney Yoshihiko Iinuma Figure 3 Engine RPM-1 Figure 4 Engine RPM-1 Figure 5 Figure 6! ! ! 1';' Figure 7

Claims (1)

[Claims] An engine valve system is equipped with a camshaft equipped with a valve lift cam to open and close the valve, and a camshaft drive mechanism that rotates the camshaft to control the operation and stop of the valve. A valve operation stop device for an engine valve system, characterized in that a clutch mechanism is provided for connecting and disconnecting a camshaft driving force from the camshaft driving mechanism to the camshaft.