JPH0224889Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention belongs to the technical field of an automatic control device for the number of operating cylinders of an engine.

<Prior Art> Conventionally, there is a device of this kind as shown in FIG. The valve-side tip 51a of the locker arm 51 that pushes down the intake and exhaust valve 50 is configured to be movable hydraulically or electromagnetically, and when the engine is operated with fewer cylinders, the valve-side tip 51a is moved back and forth for suction. Exhaust valve 5
0 is not activated.

<Problems to be solved by the invention> When the device configured as described above is implemented in a diesel engine that directly supplies fuel from the fuel injection nozzle to the combustion chamber 52, while the intake and exhaust valves 50 are not operating, Also, fuel is supplied from the fuel injection nozzle to the combustion chamber and accumulates and accumulates, and as a result, the piston 54
This cannot be carried out because there is a risk of damage to the cylinder head 53, etc.

In addition, the rocker arm 51 is constantly oscillated by the valve drive cam 55, and the lower surface of the tip 51a of the rocker arm 51 is not located above the upper end of the valve shaft of the intake/exhaust valve 50.
When 1a is advanced, the advanced tip 51a hits the valve stem 56 from the side, bending or breaking the valve stem 56. Therefore, the timing for advancing the tip 51a of the rocker arm 51 when returning from cylinder reduction operation to normal operation is It's difficult. Therefore, in order to accurately adjust the timing, it is necessary to further provide a complicated device for that purpose, which becomes expensive.

<Means for solving the problem> The present invention was proposed in order to solve the above problem.A cam is rotatably fitted onto the camshaft of the engine, and the cam is connected to the camshaft via a hydraulic clutch. The hydraulic clutch is configured so that the clutch piece is pressed toward the clutch disengaged side by a spring in the clutch chamber, and is also pressed toward the clutch inlet side by hydraulic pressure from a hydraulic chamber formed within the camshaft. is formed between the fitting surface of the camshaft and the cam, the chamber portion of the clutch chamber on the camshaft side is formed on the outer peripheral surface of the camshaft, the clutch piece is arranged in the direction of rotation of the camshaft, and the above hydraulic chamber is located inside the camshaft. The lubricant is connected to the discharge passage of the engine's lubricating pump through an oil hole formed in the lubricant.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows a longitudinal sectional front view of a fuel injection cam, and FIG. 2 shows a schematic front view of a three-cylinder diesel engine.

In the figure, reference numeral 1 denotes an engine, and this engine 1 is integrally formed with a cylinder block 4 in which a piston 3 is slidably installed above a crankcase 2, and a cylinder head 5 and a head cover 6 are mounted on the upper part of the cylinder block 4. are placed and fixed in order.

A piston 3 housed in a cylinder block 4 is connected by a connecting rod 8 to a crankshaft 7 rotatably supported on a crankcase 2.

A main combustion chamber 9 is formed between the upper surface of the piston 3 and the lower surface of the cylinder head 5.
is connected to an intake/exhaust port 10 formed in the cylinder head 5 and an auxiliary combustion chamber 11.

The intake/exhaust port 10 and the main combustion chamber 9 are connected to each other by a valve drive cam 1 which is linked to the rotation of the crankshaft 7.
2. Opening/closing is controlled by controlling intake/exhaust valves 17 via a valve operating mechanism 16 composed of a tappet 13, a push rod 14, and a rocker arm 15.

A fuel injection nozzle 18 faces the sub-combustion chamber 11, and is configured to supply fuel pumped from a fuel injection pump 19.

Among the three fuel injection cams 20 that drive the fuel injection pump 19, the central fuel injection cam 20 has a
An automatic cylinder number control device 21 is provided that automatically reduces the number of cylinders in operation when the engine 1 is operated at low speed.

This operating cylinder number automatic control device 21 is shown in FIG.
As shown in FIGS. 3 and 4, the fuel injection cam 20 is rotatably fitted onto the fuel camshaft 22 which rotates in conjunction with the crankshaft 7, and the fuel injection cam 20 is attached to the fuel camshaft 22 by a hydraulic clutch. It is configured such that it can be switched on and off via 23.

The hydraulic clutch 23 has clutch chambers 24a and 2 between the fitting peripheral surfaces of the fuel camshaft 22 and the fuel injection cam 20.
4b, a clutch chamber 24a portion formed on the outer peripheral surface of the fuel camshaft is communicated with a hydraulic oil hole 25 formed in the fuel camshaft 22 to form a hydraulic chamber 26, and a cam is connected to the opening of the hydraulic chamber 26. The clutch piece 27 is swingably arranged in the direction of rotation of the shaft, and when lubricating oil is supplied to the hydraulic chamber 26, the tip 27a of the clutch piece 27 on the rotational direction side rises, and the fuel injection cam is activated. The fuel injection cam 2 enters the clutch chamber 24b on the 20 side and is locked on the side wall 28.
0 rotates together with the fuel camshaft 22.

Lubricating oil is supplied to the hydraulic chamber 26 through a lubricating oil supply path (discharge path) 31 that pumps lubricating oil in an oil pan 29 formed at the bottom of the crankcase 2 to each lubricated part of the engine 1 using a lubricating oil pump 30. As shown in FIG. 4, the lubricating oil is supplied to the bearing portion 22a of the fuel camshaft 22 through the connecting oil passage 32 branching from the lubricating oil supply passage 31 and the fuel camshaft 22. A switching control valve 33 is provided in the connecting oil passage 32.

The switching control valve 33 is composed of an electromagnetic directional switching valve, and as shown in FIG. is supplied to switch the switching control valve 33 from the lubricating oil supply position 36 to the oil return position 37.

Lubricating oil is supplied to the hydraulic chamber 26 and the clutch piece 27
A push-back tool 39 is pressed by a spring 38 in the axial direction of the fuel camshaft 22 on the upper surface portion of the clutch chamber 24b on the side of the fuel injection cam 20 where the clutch piece 27 is inserted and locked into the hydraulic chamber 26. A push-back device 40 is provided for pushing back.

The operation of the automatic control system for the number of operating cylinders configured as described above will be explained below.

When the engine 1 is in a high-speed operating state, the operating speed detection circuit 34 detects this and the switching valve 33
is maintained at the lubricating oil supply position 36, and the lubricating oil pump 30 is
Lubricating oil is supplied from the lubricating oil supply path 31 to the hydraulic chamber 26 through the connecting path 32, the switching control valve 33, and the hydraulic oil hole 25, and the clutch piece 27 of the hydraulic clutch 23 is applied to the elastic force of the spring 38. The clutch piece 27 is pushed with strong hydraulic pressure against the resistance, and the clutch piece 27 is forced to enter the clutch chamber 24b on the side of the fuel injection cam 20, and the tip 27a of the clutch piece 27 is engaged with the side wall 28 of the clutch chamber 24b, so that the fuel injection cam 20 is connected to the fuel cam. Since it rotates together with the shaft 22, fuel is supplied to the fuel injection nozzles 18 of all cylinders, and the engine 1 is rotated at high output.

Next, when the engine 1 is operating at a low speed such as idling, the operating speed detection circuit 34 detects this and supplies the current from the battery 35 to the switching control valve 33, so that the switching control valve 33 is operated from the lubricating oil supply position 36. It switches to the oil return position 37.

When the switching control valve 33 reaches the oil return position 37, since the clutch piece 27 of the hydraulic chamber 26 is pressed by the spring 38 of the push-back device 40, the lubricating oil in the hydraulic chamber 26 flows into the hydraulic oil path 25 and the switching control valve. 33
is returned to the oil pan 29 through the clutch piece 2.
7 retreats into the hydraulic chamber 26, and the fuel injection cam 20 in this portion is no longer driven by the fuel camshaft 22. Therefore, the drive of the fuel injection cam 20 is stopped, and the cylinders to which fuel supply from the fuel injection pump 19 has been stopped stop operating.

What is shown in FIG. 5 shows another embodiment,
The clutch piece 27 is swingably supported on the fuel camshaft 22, and the end on the lagging side of the rotational direction from the pivot point 41 is pressed by a spring 38, thereby urging the clutch piece 27 to move back toward the hydraulic chamber 26. This is how it was done.

Note that the following may be considered as a modification of the above embodiment.

(b) Make the engine 2 cylinders or 4 cylinders or more, and
In the case of more than one cylinder, the number of cylinders to be operated with reduced cylinders is set to two or more.

(b) If the engine is an electric ignition type engine, an automatic cylinder number control device shall be installed on the valve drive cam for driving the intake and exhaust valves.

(c) In addition to or in place of the operating speed detection circuit that controls the supply of battery current to the switching control valve of the automatic cylinder number control device, a circuit that controls the supply of current to the switching control valve according to engine load fluctuations. Make it.

(d) Due to the balance between the elasticity of the spring that presses the clutch piece of the hydraulic clutch so that it moves into and out of the hydraulic chamber, and the protruding force of the clutch that is protruded by the hydraulic pressure supplied to the hydraulic chamber, when the engine rotates at low speed, The elasticity of the spring overcomes the protruding force of the clutch and controls the clutch piece to move back into the hydraulic chamber so that the cam is not driven. In this case, the switching control valve can be omitted.

<Effects> Since the present invention is constructed and operates as described above, it has the following effects.

That is, in diesel engines, a hydraulic clutch is installed in the fuel injection cam to control the supply of fuel to the cylinder whose cylinders are to be reduced, and in electric ignition engines, a hydraulic clutch is installed in the valve drive cam to control the supply of fuel to the cylinder whose cylinders are to be reduced. By cutting off the supply of air-fuel mixture,
The automatic cylinder number control device can be implemented regardless of the ignition type of the engine.

Moreover, even when switching from reduced-cylinder operation to normal operation, even if the timing is when the clutch chamber is removed, the camshaft is always engaged once it rotates and the cam can be driven. This prevents damage to the intake and exhaust valves due to a shift in the timing of switching from cylinder reduction operation to active operation as in the conventional example. This eliminates the need for a complicated device for timing alignment and can be implemented at low cost. Furthermore, when the clutch piece placed on the rotating camshaft is engaged with the cam to switch from reduced-cylinder operation to normal operation, the clutch piece is placed in the direction of rotation of the camshaft, so the engagement Since the stress in the rotational direction that is sometimes applied to the clutch piece is absorbed in the length direction of the clutch piece, not only will the clutch piece not be deformed or damaged, but also the clutch piece will be pressed with strong hydraulic pressure, so the clutch piece will be held securely. This allows normal operation to be carried out reliably.

[Brief explanation of drawings]

Figures 1 to 5 show an embodiment of the present invention, Figure 1 is a longitudinal cross-sectional view of the cam and camshaft, Figure 2 is a schematic front view of the diesel engine, and Figure 3 is a longitudinal cross-sectional side view of the main parts. 4 is a partially longitudinal side view of the fuel injection pump section, FIG. 5 is a view corresponding to FIG. 1 of the main part showing another embodiment, and FIG. 6 is a schematic front view of the main part of the conventional example. It is a diagram. 1... Engine, 20... Cam, 22... Camshaft, 23... Hydraulic clutch, 24a, 24b...
Clutch chamber, 25...Oil hole, 26...Hydraulic chamber, 2
7...Clutch piece, 30...Lubrication oil pump, 31
...Discharge path (lubricating oil supply path), 38...Spring.

Claims (1)

[Scope of utility model registration request] A cam 20 is rotatably fitted onto a camshaft 22 of the engine 1, and the cam 20 is connected to the camshaft 22 so that it can be switched on and off via a hydraulic clutch 23. 27 to the clutch disengaged side with a spring 38, and a hydraulic chamber 26 formed within the camshaft 22.
Clutch chambers 24a and 24b are formed between the fitting surfaces of the camshaft 22 and the cam 20, and the clutch chambers 24a and 24b are
The chamber portions 24a of a and 24b on the camshaft 22 side are formed on the outer circumferential surface of the camshaft, the clutch piece 27 is arranged in the camshaft rotation direction, and the hydraulic chamber 26 is inserted through the oil hole 25 formed in the camshaft 22. An automatic control device for the number of operating cylinders of an engine, characterized in that the engine is connected to a discharge passage 31 of a lubrication pump 30 of an engine 1.