JP2005264838A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine superior in quickness at starting/stopping the engine and in responsiveness to an output change and suitable to compact and smaller construction without the need for a special valve structure and a flow path control structure by keeping a cylinder operation capacity optimum in each engine operating stroke to achieve more efficient engine output. <P>SOLUTION: The engine 10 comprises (a) the cylinder 11 having a fuel supply part and its exhaust part on the cylinder peripheral wall, (b) a driving piston 14 out of which power is taken and a control piston 15 for controlling a cylinder space into which fuel is supplied, both of which have piston faces opposed to each other in the cylinder 11, and (c) a link mechanism connected to a rotating power shaft 14b of the driving piston 14 via a cam for driving the control piston 15 along a predetermined cam curve. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine having opposed pistons that reciprocate in a cylinder.

As engines for automobiles, an internal combustion engine system in which fuel oil such as gasoline or light oil or fuel gas such as propane gas is pressurized by a piston in a cylinder and burned is often used.
Conventionally, in such an internal combustion engine system or the like, an engine has been developed in which engine output and the like are increased by using a pair of pistons arranged opposite to each other in a cylinder. For example, the following technologies are known in relation to such an engine.

  Patent Document 1 discloses an engine in which a plurality of pistons are provided for each cylinder. Each piston moves so as to be spread outward in a fuel intake process, and each piston approaches each other in a compression process. A four-cycle engine is described in which each piston moves outward in the movement and explosion process, and moves close to each other in the exhaust process.

  In Patent Document 2, a piston having a flat or curved notched recess at the upper surface end of the piston is horizontally installed and opposed so that the recess is downward in a cylinder provided with a fuel injection valve in the center.・ Pneumatic tank, supply port, and exhaust port with crank chambers at both ends of the cylinder to form closed chambers, exhaust ports / suction ports at both ends of the cylinder or at appropriate positions in the crank chamber, and adjustment of indoor pressure or air supply. , And a horizontally opposed engine provided with a valve for controlling the flow at each inlet / outlet.

Patent Document 3 includes a first piston and a second piston that reciprocate by a unique crank portion in a cylinder, a first compression chamber formed by the first piston and the cylinder, a second piston and the cylinder. The formed second compression chamber communicates with each other at the top dead center side, and the first piston and the second piston are synchronized with each other by providing a phase at the top dead center of the first piston and the second piston. An engine is described which converts a reciprocating motion of two pistons into a rotational motion.
Japanese Patent Laid-Open No. 6-200783 JP-A-8-93498 Japanese Patent Laid-Open No. 11-257090

However, the conventional technique has the following problems.
(1) In a 4-cycle engine in which a plurality of pistons are provided for each cylinder described in Patent Document 1, a plurality of pistons are reciprocated symmetrically with respect to the center of the cylinder. This is just a connection of the normal engine, and it is not possible to optimize the operating volume in the cylinder for each process to make the engine output more efficient, resulting in increased fuel consumption and increased exhaust gas volume. There were issues such as.
(2) Since the horizontally opposed engine described in Patent Document 2 connects a pneumatic tank that performs pressure adjustment and the like, a supply port and a discharge port of the cylinder, and a valve that adjusts and controls the flow at each inlet and outlet, the control valve in the cylinder In addition, the structure of the fuel flow path and the like becomes complicated and difficult to control, and the engine becomes large in size.
(3) In the engine in which the piston cycles of the first piston and the second piston described in Patent Document 3 are synchronized, both pistons are simply connected via a link structure. Even if they are different from each other, both pistons basically function in the same way in the engine cycle from each intake to exhaust, so that the engine output cannot be taken out properly and efficiently, and the engine can be started and stopped quickly. There were problems such as lack of responsiveness to output changes.

  The present invention has been made in order to solve the above-described conventional problems, and optimizes the operation volume in the cylinder for each engine operation process to improve engine output efficiency, speeding up engine start / stop and response to output change. An object of the present invention is to provide an engine that is excellent in performance and that is compact and suitable for downsizing without requiring a special valve structure or flow path control structure as in the prior art.

(1) The engine of the present invention includes: (a) a cylinder having a fuel supply portion and an exhaust portion thereof provided on a cylinder peripheral wall; and (b) a drive piston from which the respective piston surfaces are arranged to face each other in the cylinder to extract power. A control piston that controls a cylinder space to which fuel is supplied, and (c) a link mechanism that is connected to a rotating power shaft of the drive piston via a cam and drives the control piston with a predetermined cam curve. Configured.

(2) The engine of the present invention is characterized in that, in (1), a fuel ignition part is disposed on the cylinder peripheral wall between the top dead center and the bottom dead center of the drive piston. Yes.

(3) In the engine of the present invention, in (1) or (2), the cam curve representing the operation state of the control piston indicates that the control piston is placed in the cylinder in the intake-compression-combustion-exhaust engine operation process. It has a plurality of flat regions to keep at a fixed position.

  According to the engine of the present invention, a drive piston and a control piston whose piston surfaces are opposed to each other in the cylinder, and a power shaft rotating the drive piston are connected via a cam to connect the control piston to a predetermined cam curve. Therefore, it is possible to make the engine output efficient by optimizing the operation volume in the cylinder for each engine operation process. Furthermore, it is excellent in quick start / stop of the engine and responsiveness to changes in output, and is suitable for downsizing without requiring a special valve structure or flow path control structure as in the prior art.

  According to the engine of the present invention, the fuel ignition unit is disposed on the cylinder peripheral wall between the top dead center and the bottom dead center of the drive piston. Is shielded and can effectively prevent malfunction of the fuel ignition part, and is excellent in maintainability.

  According to the engine of the present invention, the cam curve representing the operation state of the control piston has a plurality of flat regions that keep the control piston at a fixed position in the cylinder in an intake-compression-combustion-exhaust engine operation process. Therefore, the engine cycle can be executed while appropriately controlling the cylinder space formed between the piston surfaces of the control piston and the drive piston for each engine operation process, and the engine cycle can be performed via the power shaft of the drive piston. The engine can be operated by taking out the output more efficiently.

In the present invention, a drive piston and a control piston, each of which has a piston surface facing each other, are arranged in a cylinder, and a control piston is connected to a power shaft of the drive piston via a link mechanism to obtain a predetermined cam curve. It is made to drive. As a result, the operating volume in the cylinder is optimized for each cycle of the engine to improve the efficiency of the engine output. Furthermore, it is excellent in quick start / stop of the engine and responsiveness to output change, and is also suitable for downsizing.
Hereinafter, the engine of the present embodiment will be described more specifically based on the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of an engine according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 10 denotes the engine of the first embodiment, and the cylinder 11 is formed in a substantially cylindrical shape with piston fitting portions at the upper and lower portions thereof. Fuel, such as gasoline or light oil, provided on the peripheral wall of the cylinder 11 from the fuel supply unit 12 is supplied into the cylinder 11, and exhaust gas generated after combustion explosion is discharged from the exhaust unit 13.
The drive piston 14 is disposed in the cylinder 11 and takes out power through a power shaft 14b connected to the crankshaft 14a.
The control piston 15 is also disposed in the cylinder 11 so as to face the drive piston 14, and a crankshaft 15a is connected to a power shaft 14b of the drive piston 14 via a link mechanism having a cam (not shown), with a predetermined cam curve. Driven.
The fuel ignition unit 16 such as an ignition plug is provided on the cylinder peripheral wall between the top dead center and the bottom dead center of the drive piston 14.

The engine 10 is a four-cycle engine having a drive piston 14 reciprocated in a cylinder 11 and a control piston 15 that controls the cylinder operating space. Engines include those for automobiles and trucks, and as power sources for industrial machines.
The engine 10 also includes known subsystems such as an intake system, an exhaust system, a lubrication and cooling system, a turbo and supercharger system, a transmission, and the like (not shown).
The cylinder 11 can be applied with its axis held in the horizontal direction or the vertical direction, and the drive piston 14 and the control piston 15 are arranged with the respective piston surfaces facing each other at openings at both ends thereof.
The fuel supply unit 12 includes a fuel injector 12a and a valve unit 12b that is driven in conjunction with an accelerator (not shown) and adjusts combustion air and the like.
The exhaust unit 13 includes a valve unit (not shown) that is driven to open and close in conjunction with the power shaft 14b of the drive piston 14, and exhausts the fuel exhaust gas burned in the cylinder 11 to the outside at a predetermined timing.

A base end side of the crankshaft 14a is rotatably attached to the drive piston 14, and the other end side of the crankshaft 14a is fixed to a connecting portion 14c of a power shaft 14b that is rotationally driven. As a result, when the drive piston 14 is driven to reciprocate in the cycle of the intake to exhaust processes, the power of the reciprocating motion is converted into rotational motion, and engine output is obtained via the power shaft 14b.
The control piston 15 is connected to the power shaft 14b of the drive piston 14 by a link mechanism having a cam (not shown). The base end of the crankshaft 15a is connected to the control piston 15, the other end is rotatably attached to the connecting portion 15b, and a rotating shaft 15c is disposed at the base of the connecting portion 15b. The rotating shaft 15c is connected to the link mechanism and driven in a predetermined angle range β, for example, a range of 70 to 90 °, preferably 85 ° ± 2 °, so that the control piston 15 has a predetermined cam curve. It moves up and down in the cylinder.

  The cam is a mechanical element that rotates with a predetermined contour shape, and gives a predetermined motion to a follower that is a counterpart by direct contact thereof. There are cam followers, levers, links, and the like as followers to which motion is given by cams, and the motion of the follower operating end, which is the final follower, is expressed as a cam curve. As the cam curve, a well-known deformed trapezoidal curve, a deformed sine curve, a deformed isovelocity curve, or a combination of them can be applied according to the engine operation process.

FIG. 2 is an explanatory diagram showing an example of an operating state in the engine of the first embodiment, FIG. 3 (A) is an explanatory diagram of a cam curve in the control piston, and FIG. 3 (B) is synchronized with the control piston. It is an operation state figure of a drive piston made.
As shown in FIG. 3B, the engine 10 is a four-cycle engine, and (1) intake → (2) compression → (3) while the power shaft 14b of the drive piston 14 rotates twice (720 °). Combustion → (4) Engine operation process by exhaust is executed.
FIG. 3A shows a change in the position of the control piston 15 moved up and down in the cylinder 11 in response to a change in the rotation angle (θ) of the power shaft 14b of the drive piston 14, that is, a link having a cam. The cam curve of the control piston 15 operated by the mechanism is shown. This cam curve has flat regions (H, M, L) for keeping the control piston 15 at three positions, i.e., high, middle, and low, in the cylinder 11, and the working space held in the cylinder is defined as the engine operating process. Each can be controlled appropriately.

The operation states of the drive piston 14 and the control piston 15 in each operation process of the engine 10 will be described with reference to FIG.
FIGS. 2A to 2C are explanatory diagrams showing the operating state of the control piston 15 when the rotation angle (θ) of the power shaft 14b is θ = 0 °, θ = 225 °, and θ = 450 °, respectively.
As shown in FIG. 3, in the intake step of the rotation angle θ = 0 ° to 180 °, the control piston 15 is set in the flat region H that maintains the high position in the initial stage, but the rotation angle θ = 120 °. When the position is reached, the control piston 15 starts to move down to the flat region M where the middle position is maintained.
As a result, a large space is formed between the pistons in the initial state so as to ensure a sufficient intake volume.
Further, in the compression process of the rotation angle θ = 180 ° to 420 °, the control piston 15 is lowered from the state where the control piston 15 is maintained in the middle flat region M to the lower flat region L, and the space is compressed by the upper and lower pistons. Then, a high compression rate is ensured, and ignition is performed at a position of the rotational angle θ = 420 °, which is the time when the control piston 15 reaches the flat region L at the low position.
Further, in the combustion process at the rotation angle θ = 420 ° to 540 °, the control piston 15 is held in the flat region L at a low position and the drive piston 14 is pushed down.
Then, in the exhaust process of the rotation angle θ = 540 ° to 720 °, the control piston 15 is shifted from the flat region L at the low position to the flat region H at the high position after passing through the flat region M at the middle position and driven. The piston 14 is pushed up.

As described above, the engine 10 according to the first embodiment includes the drive piston 14 and the control piston 15 that are disposed opposite to each other in the cylinder 11, and is connected to the power shaft 14b of the drive piston 14 via the cam. Is driven by a predetermined cam curve, and the cam curve of the control piston 15 keeps the control piston 15 at a fixed position in the cylinder 11 in the intake-compression-combustion-exhaust engine operation process. , H, M, and L, the cylinder space formed between the piston surfaces of the control piston 15 and the drive piston 14 can be appropriately controlled for each engine operation process. The engine 10 can be operated more efficiently through the power shaft 14b.
Further, since the fuel ignition unit 16 is disposed on the cylinder peripheral wall between the top dead center and the bottom dead center of the drive piston 14, the fuel ignition unit 16 is connected to the drive piston 14 itself in a combustion process such as an intake process. , And can effectively prevent malfunction of the fuel ignition unit 16 and is excellent in maintainability.

(Embodiment 2)
FIG. 4 is a schematic configuration diagram of an engine according to Embodiment 2 of the present invention. FIG. 5A is an explanatory diagram of a cam curve in the control piston, and FIG. 5B is synchronized with the control piston. It is an operation state figure of a drive piston.
In FIG. 4, reference numeral 20 denotes the engine of the second embodiment, and the support portion 21 is connected to the power shaft 14 b of the drive piston 14 via a link mechanism having a cam (not shown), and the control piston has a predetermined cam curve. The 15 crankshafts 15a are moved up and down.
The main part of the engine 20 according to the second embodiment is the same as that of the engine 10 according to the first embodiment.
As shown in FIG. 5 (B), the engine 20 is a two-cycle engine in which the intake-compression-combustion (explosion) -exhaust engine operating steps proceed while the power shaft 14b of the drive piston 14 rotates 360 °. There is a cam curve of the control piston 15 corresponding to the rotation of the power shaft 14b as shown in FIG.
Such a cam curve is an example, and known ones such as a deformed trapezoid curve, a deformed sine curve, and a deformed isovelocity curve can be applied, and the actual speed and acceleration are calculated from these speed and acceleration values, It can be determined whether the cam mechanism is appropriate.

Here, FIG. 6 is a partially enlarged configuration diagram of a modified example of the control piston of the engine 20.
In FIG. 6, reference numeral 30 denotes a control piston according to a modification of the second embodiment,
The airway 31 is formed so as to penetrate the upper and lower surfaces of the control piston 30, and the fuel gas vaporized in the lower cylinder space 11 a between the lower part of the control piston 30 and the upper part of the drive piston 14 is converted into the cylinder upper space above the control piston 30. 11b.
The lid portion 32 is provided at the upper end portion of the cylinder 11 for forming the cylinder upper space 11b, and the crankshaft 15a of the control piston 30 is inserted vertically while maintaining airtightness. A valve valve 33 is provided in the airway 31.
In the engine 20 of this modification, the fuel gas vaporized in the cylinder lower space 11a is first introduced into the cylinder upper space 11b as the control piston 30 is lowered. When the control piston 30 moves up, the fuel gas in the cylinder upper space 11 b is compressed, and the valve valve 33 leading from the cylinder upper space 11 b to the cylinder lower space 11 a is opened. The fuel gas is controlled through the airway 31. The piston 30 is moved into the cylinder lower space 11a below the piston 30 and compressed.
And it is ignited when the control piston 30 reaches the flat region L at the low position.
The cylinder 11 is provided with an exhaust passage and an exhaust valve system (not shown) for exhausting the fuel gas in the cylinder upper space 11b as necessary, whereby each cycle in the engine operation process proceeds smoothly. Like that.
As described above, the engine 20 including the modified control piston 30 has cylinder spaces 11b and 11a respectively connected to the upper and lower portions of the control piston, and operates the drive piston 14 of the engine 20. By dividing the cylinder space into two stages via the control piston 30, a two-cycle engine capable of appropriately adjusting the cycle process is realized.

  The engine 20 according to the second embodiment is configured as described above, and includes the support portion 21 for moving the crankshaft 15a of the control piston 15 up and down along a predetermined cam curve. Therefore, in addition to the operation of the first embodiment. In addition to being excellent in mechanical strength and durability, it is excellent in quick start / stop of the engine and responsiveness to output changes.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an engine for automobiles and the like, and can provide an engine that is compact and suitable for downsizing as well as being able to optimize the operating volume in the cylinder for each engine operating process to increase the engine output efficiency. it can.

1 is a schematic configuration diagram of an engine according to Embodiment 1. FIG. FIG. 3 is an operation state explanatory diagram of the engine according to the first embodiment. (A) It is a graph of the cam curve in a control piston. (B) It is an operation state figure of a drive piston. 3 is a schematic configuration diagram of an engine according to Embodiment 2. FIG. (A) It is explanatory drawing of the cam curve in a control piston. (B) It is an operation state figure of a drive piston. FIG. 10 is a schematic configuration diagram of an engine in a modification of the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine of Embodiment 1 11 Cylinder 11a Cylinder lower space 11b Cylinder upper space 12 Fuel supply part 12a Fuel injector 12b Valve part 13 Exhaust part 14 Drive piston 14a Crankshaft 14b Power shaft 14c Connection part 15 Control piston 15a Crankshaft 15b Connection Part 15c Rotating shaft 16 Fuel ignition part 20 Engine of Embodiment 2 21 Supporting part 30 Modified control piston 31 Airway 32 Lid part 33 Valve valve

Claims (3)

  (A) A cylinder provided with a fuel supply part and its exhaust part on the cylinder peripheral wall, (b) a drive piston from which the respective piston faces are arranged oppositely in the cylinder and power is taken out, and a cylinder space to which fuel is supplied And (c) a link mechanism that is connected via a cam to a rotating power shaft of the drive piston and drives the control piston with a predetermined cam curve.   The engine according to claim 1, wherein a fuel ignition part is disposed on the cylinder peripheral wall between a top dead center and a bottom dead center of the drive piston. The cam curve representing the operating state of the control piston has a plurality of flat regions that keep the control piston at a fixed position in the cylinder in an intake-compression-combustion-exhaust engine operation process. The engine according to claim 1 or 2.

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