JPH0542652U - Variable cylinder engine - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a variable cylinder engine with reduced friction loss and improved fuel efficiency. In a variable cylinder engine capable of deactivating some of a plurality of cylinders during engine operation, an exhaust valve 19 and an intake valve 20 of a deactivated cylinder 12 are exhausted while a piston 15 is near top dead center. When both are in place, fix them together in the closed state. As a result, the minimum amount of gas is enclosed in the cylinder 12, and the subsequent piston movement causes the cylinder 12 to repeatedly expand and contract to less than 1 atm, thereby reducing the absolute value of stroke loss. Further, since air is not sucked and discharged in the cylinders 12 that are at rest, there is no loss due to air viscosity or inertia.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable cylinder engine that can change the number of cylinders that operate according to operating conditions.

[0002]

[Prior Art]

 Conventionally, a variable cylinder engine has been proposed in which a part of a plurality of cylinders of an engine is deactivated according to operating conditions. This is, for example, to stop fuel supply to a specific cylinder during low-speed traveling or light-load traveling, and to operate the engine only in the remaining cylinders, which can improve fuel efficiency.

[0003]

[Problems to be solved by the device]

 In a conventional variable cylinder engine, the exhaust valve and the intake valve continue to open and close even when the cylinder is at rest, just like other cylinders that are operating. Therefore, there was the following friction loss in the idle cylinder, and there was still room for improvement.

That is, in the compression stroke, the air in the cylinder is pressurized from one atmospheric pressure to several to several tens of atmospheric pressure in accordance with the compression ratio, and in the expansion stroke, the high atmospheric pressure is reduced to one atmospheric pressure. In this case, as shown in FIG. 3, the PV diagram takes different paths in the compression process and the expansion process, and the area surrounded by the diagram becomes the cooling loss. This loss is a relatively large amount of energy because the compression is performed up to a high pressure.

Furthermore, originally unnecessary air is sucked into the cylinder and exhausted from the cylinder during the intake stroke and the exhaust stroke, and friction loss is inevitably generated during the intake and exhaust processes.

Therefore, the present invention is to provide a variable cylinder engine that reduces the above-mentioned loss and improves fuel efficiency.

[0007]

[Means for Solving the Problems]

 A variable cylinder engine according to the present invention that achieves this object is a variable cylinder engine that can suspend some of a plurality of cylinders during engine operation. It is characterized in that when the piston is in the vicinity of top dead center in the exhaust stroke, both are fixed in the closed state.

[0008]

[Action]

 If the exhaust valve and the intake valve are both fixed and closed when the piston is near top dead center in the exhaust stroke, the minimum amount of gas is enclosed in the cylinder. Therefore, the subsequent piston movement causes expansion and contraction of less than 1 atm in the cylinder to be repeated, and the absolute values of stroke loss and cooling loss decrease. Further, since air is not sucked and discharged in the cylinder, loss due to air viscosity and inertia is eliminated.

[0009]

【Example】

 Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a sectional view of an essential part of a variable cylinder engine according to an embodiment of the present invention.

As shown in FIG. 1, the engine 11 of this embodiment has a plurality of cylinders 12, and each cylinder 12 is composed of a cylinder block 13 and a cylinder head 14 as in a normal engine. A piston 15 is installed in the cylinder head 14, and an exhaust hole 16, an intake hole 17 and a fuel injection hole 18 are formed in the cylinder head 14, and an exhaust valve 19, an intake valve 20 and a fuel injection nozzle 21 are arranged therein. It is set up.

In this embodiment, the exhaust valve 19 and the intake valve 20 are not driven by a cam but are opened / closed by two actuators 22, 23 operated by high pressure air. According to such actuators 22 and 23, the valves 19 and 20 can be opened and closed at an arbitrary timing by controlling the electromagnetic coil inside by a signal from a controller (not shown).

On the other hand, when the cylinder 12 is deactivated according to the operating condition, the fuel supply from the fuel injection nozzle 21 is stopped and the valve movement is stopped by a signal from a controller (not shown). Here, in the present invention, the valve movement is stopped with both valves 19 and 20 closed together when the piston 24 is near the top dead center in the exhaust stroke of the cylinder 12. That is, the exhaust valves 19 are closed by the actuators 22 and 23 while the exhaust valve 19 is closed and the exhaust valves 19 are closed before the intake valves 20 are opened.

As described above, if the exhaust valve 19 and the intake valve 20 are both fixed in the closed state when the piston 24 is near the top dead center in the exhaust stroke, a minimum amount of gas is enclosed in the cylinder 12. .. Therefore, expansion / contraction of less than 1 atm is repeated in the cylinder 12 which is in a rest state due to the piston movement accompanying the subsequent engine operation. The PV diagram at this time is shown in FIG. As shown in FIG. 2, in this case, the absolute value of the change in pressure is smaller than that in the above-described conventional FIG. 3, and therefore the absolute value of the stroke loss is also reduced.

On the other hand, since air is not sucked and discharged in the cylinders 12 that are at rest, the loss due to the viscosity and inertia of the air is eliminated as compared with the case where air is wastefully sucked and discharged.

Next, an example of the above-mentioned actuators 22 and 23 will be described. Since the actuators 22 and 23 have the same structure but different operation timings, only one of them will be described here.

4 to 10 are vertical cross-sectional views of the actuator 22 having different operating states. The actuator 22 has an upper and lower symmetry, and the upper member corresponding to the lower member is indicated by the same numeral as the lower member with a subscript a.

As shown in FIG. 4, the actuator 22 has an output shaft 31, and the engine valve 19 is fixed to one end of the output shaft 31. Further, the actuator 22 has, in its housing 39, a low-mass main piston 33 equipped with an O-ring 43 and air valves 35 and 35a. The air valves 35 and 35a are locked by the permanent magnets 41 and 41a at fixed positions, respectively, and are moved from the respective positions by pulse excitation of the coils 45 and 45a by the controller. The air valves 35 and 35a have annular bodies having hollow valve shafts 37 and 37a extending therefrom, respectively. The air valves 35, 35a are adapted to cooperate with the main piston 33 and the housing 39 to perform various opening / closing operations during the operation of the actuator 22. The housing 39 has high-pressure cavities 59 and 59a that are pressurized to about 100 psi gauge by a pump (not shown) and low-pressure cavities 61 and 61a that are open to the atmosphere.

FIG. 4 shows the initial state in which the main piston 33 is at the lower end position and the air valve 35 is closed. In this state, the annular ring 49 of the air valve 35 is in the annular groove of the housing 39 and is in contact with the O-ring 51 for sealing. As a result, the compressed air in the cavity 59 is confined and the force is prevented from being exerted on the main piston 33. At this position, the main piston 33 is pressed downward by the force of the compressed air in the cavity 64a. The pressure of this compressed air is greater than that of the cavity 61a. The cavity 61a communicates with the surface 34 of the recessed body 52 in FIG. 4 via an annular passage 36a parallel to the hole 42a in the air valve 35a and parallel to the passage 71 in the body 52a. The annular passages 36, 36a are formed when the air valves 35, 35a are in the closed position, respectively, and are closed when the air valves 35, 35a are in the open position, respectively. The body 52, 52a having a recess is attached to and integrated with the main piston 33. Shallow recesses 46 and 46a, 54 and 54a are formed in bodies 52 and 52a, respectively. When the main piston 33 is at the lower end, the surface 62 of the main piston 33 communicates with the low pressure cavity 61 via the valve port 53, the hole 42 and the passage 36.

In FIG. 5, the reciprocating air valve 35 moves downward by, for example, 1.5 mm, while the main piston 33 is still in a state where high-pressure air flows from the cavity 59 to the body 52. Driving force is applied to the lower surface 62 of the main piston 33 through four shallow recesses 54 that are circumferentially equidistantly provided. The air valve 35 is opened by applying an electric pulse to the coil 45 that temporarily weakens or disables the restraining force of the armature 40 by the permanent magnet 41. The armature 40 is fixed to the end of the valve shaft 37. When the restraint force is temporarily disabled, the air pressure in the cavity 59 acted by the pressure in response to the first annular surface 69 of the air valve 35 causes the air valve 35 to open. With the downward movement of the air valve 35, the annular shoulder 44 blocks the communication between the cavity 57 and the cavity (low pressure air outlet) 61 formed between the second annular surface 38 and the housing wall 47. To be. While the air valve 35 is moving, communication between the cavity 59 and the surface 62 is achieved via the ring 49 of the air valve 35, and a force for moving the main piston 33 upward acts.

Only when the annular shoulder 63 of the air valve 35 engages the end of the recess 54, the ring 49 moves away from the annular groove of the housing 39 to fully transfer the pressure of the cavity 59 to the recess 54 and the cavity 64 (see FIG. 6).

FIG. 6 shows a state in which the air valve 35 is substantially fully opened and opened about 2.8 mm, and the main piston 33 moves upward by about 3.5 mm. In FIG. 5, high-pressure air is supplied to the cavity 57 and the surface 62 of the main piston 33 and starts moving upward. The supply of high pressure air to the cavity 64 is stopped when the end of the recess 54 passes through the annular shoulder 75 of the housing 39. However, the main piston 33 continues to move upward due to the force of the high pressure air in the cavity 64. There are a plurality of holes 42 around the air valve 35. When the annular shoulder 65 of the air valve 35 makes the cavity 59 and the cavity 57 communicate with each other via the recess 46 and the hole 42 by the relative movement of the air valve 35 and the main piston 33 in the axial direction, the high pressure acting on the surface 38 causes the air valve 35 to move. A force in the closing direction (upward direction) acts. The inner annular surfaces 48, 48a of the air valves 35, 35a are at low atmospheric pressure throughout operation of the air valves, respectively.

In FIG. 7, the main piston 33 has moved about 6.1 mm and continues to move further upward in FIG. The air valve is still at the 2.8 mm position and is in the lowest fully open position. The shoulder 65 is completely away from the end of the cooperating recess 46 and directs high pressure air from the cavity 59 through the sealing surface 47 into the cavity 57 and exerts pressure on the surface 38. The air valve 35 tries to stop at this position for a short time because of the compressed air acting on the annular surface 69 and the surface connected to the annular surface 69, but since the area of the surface 38 is larger than the area of the surface 69, the air valve 35 closes the air valve 35. Receives force in the direction (upward). This significantly reduces the force required to return the air valve from the open position (bottom end), thus significantly reducing the magnetic force required for the permanent magnet 41 on the armature 40. By expelling the high pressure air of the cavity 59 through the recess 46 located behind the recess 54, the pressure on the face 38 is delayed until the main piston 33 is fully advanced and the air valve 35 is still closed.

A characteristic of the actuator 22 is that a passage 71 parallel to the axial direction exists in the body 52, 52 a and the main piston 33. These are arranged at intervals in the circumferential direction, and even during the operation of the air valves 35, 35a and the main piston 33, the pressures in the cavities 50, 50a are always equalized. This is because at least one of the cavities 50, 50a is in fluid communication with the low pressure cavities 61, 61a. This is an efficient way to keep the surfaces 48, 48a at a low pressure. Therefore, when a high pressure is applied to the cavities 57 and 57a and the air valves 35 and 35a, the cavities 57 and 57a are efficiently closed by aerodynamic force.

In FIG. 8, the air valve 35 is located approximately 2.0 mm from its closed position, is being returned to the closed position by receiving aerodynamic force on the surface 38, and the attraction force of the magnet 41 to the armature 40 is in contact. The pole 40 is about to be returned to the magnet latch. In FIG. 8, the main piston 33 has moved about 6.1 mm. In FIG. 9, the air valve 35 is about 1.5 mm from the closed position and the main piston 33 is moving about 10 mm.

An intermediate pressure of about 4 psi as a gauge pressure is introduced into the cavity 64 from the intermediate port 67 so that the high-pressure air in the cavity 64 is reduced to the intermediate pressure. The port 67 discharges the pressure of the compressed air acting on the surface 62 of the main piston 33 and removes the acceleration force from the piston. Port 67 also exerts an intermediate pressure on the opposite surface 62a of the piston which acts to drop speed when it is trapped and compressed to approach the second position. The port 67 also serves to apply an intermediate pressure to this working surface of the piston and temporarily fix the piston in the second position until the next opening operation of the air valve 35a.

FIG. 10 shows a state where both the air valves 35 and 35a are fully closed and the main piston 33 is about to reach the upper end. The high-pressure compressed air in the cavity 64a is discharged into the atmosphere through the recess 54a, the hole 42, the cavity 57a and the cavity 61.

The movement of the actuator 22 in one direction has been described above. However, since the structure of the actuator 22 is vertically symmetrical, the return movements of the air valve 35a and the main piston 33 are upside down. You can think in the same way and omit the explanation.

[0028]

[Effect of the device]

 As described above, according to the present invention, the exhaust valve and the intake valve of the cylinder to be stopped are fixed in the closed state together when the piston is near the top dead center in the exhaust stroke. The pressure in the cylinder is always maintained at 1 atm or less, and the stroke loss caused by expansion and contraction in the cylinder can be reduced. Further, since air is not sucked and discharged in the cylinders that are at rest, there is no loss due to air viscosity, inertia, etc., and in combination with the reduction in loss described above, it is possible to improve fuel efficiency of the engine. ..

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a variable cylinder engine according to an embodiment of the present invention.

FIG. 2 is a PV diagram of a deactivated cylinder according to an embodiment of the present invention.

FIG. 3 is a PV diagram of an idle cylinder of a conventional example.

FIG. 4 is a vertical cross-sectional view of a valve actuator of the variable cylinder engine of FIG.

5 is a vertical sectional view of a valve actuator of the variable cylinder engine of FIG.

6 is a vertical cross-sectional view of the valve actuator of the variable cylinder engine of FIG.

7 is a vertical cross-sectional view of the valve actuator of the variable cylinder engine of FIG.

8 is a vertical sectional view of a valve actuator of the variable cylinder engine of FIG.

9 is a vertical cross-sectional view of the valve actuator of the variable cylinder engine of FIG.

10 is a longitudinal sectional view of a valve actuator of the variable cylinder engine of FIG.

[Explanation of symbols]

11 is an engine, 12 is a cylinder, 13 is a cylinder block, 14 is a cylinder head, 15 is a piston, 16 is an exhaust hole, 17 is an intake hole, 18 is a fuel injection hole, 19 is an exhaust valve, 19 is an exhaust valve, 20 is an intake valve, and 21 is Fuel injection nozzle, 2
2, 23 are actuators, 33 are main pistons, 3
5 is an air valve, 52 is a body, 46 and 54 are recessed, 4
5 is a coil.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Negishi Inventor Hideo Negishi 3-1-1, Hinodai, Hino-shi, Tokyo Inside Hino factory

Claims (1)

[Scope of utility model registration request] 1. A variable cylinder engine in which some of a plurality of cylinders can be deactivated during engine operation, and the exhaust valve and the intake valve of the deactivated cylinder have their pistons near the top dead center in the exhaust stroke. A variable cylinder engine that is sometimes fixed in a closed state.