JP2002529634A - Method and apparatus for changing piston movement in cylinder - Google Patents

Abstract

A split-cycle machine having a first axis, the plurality of radial reciprocating pistons (60) radially disposed from the first axis, and constrained to orbit about the first axis. And a plurality of lobe axes (62) arranged in a circle. Each lobe axis is configured to be rotatable about a corresponding second axis parallel to the first axis. The lobe axis is rotationally driven by the drive means at a constant rate, which is a predetermined percentage of its trajectory rate, the plane of the lobe being substantially in the radial plane of the piston. Each piston is connected to at least one lobe such that the reciprocating motion of the lobe shaft and the reciprocating motion of the piston are synchronized with the revolving motion of the lobe shaft. The non-conformal arrangement of the axes of the successive Geneva gear groups (20, 30, 40) makes it possible to increase or decrease the duration of at least one stroke of a cycle of operation of the machine. A wide range of cycle performance characteristics can be realized by forming a pair of Geneva gear groups having left-right asymmetric lobes at unequal angles.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD [0001] The present invention relates to altering piston motion, and more particularly to "split cycle" as defined below.
A method and apparatus for varying the stroke and / or timing of the movement of a piston in a cylinder during one working cycle of the movement of the piston in the cylinder of a crank working machine.

BACKGROUND OF THE INVENTION The present invention applies to the movement of a piston in a cylinder of a rotary machine, the piston having the general shape shown in US Pat. Nos. 5,146,880 and 5,279,209, which are features of the embodiments shown in the specifications of these patents. , But undergoes linear motion in the cylinder of a rotating machine.

[0003] In particular, in the following description of the specification, a machine having a first axis, a plurality of radial reciprocating pistons arranged radially from the first axis, and around the first axis A plurality of lobe axes constrained to orbit and arranged in a circle, each lobe axis being rotatable about a corresponding second axis parallel to the first axis; The shaft is rotationally driven by the drive means at a constant rate, which is a predetermined percentage of its trajectory rate, the plane of the lobe being substantially in the radial plane of the piston, each piston having a rotational trajectory of the lobe axis. A machine connected to the at least one lobe so that the reciprocating motion of the piston and the reciprocating motion of the piston are synchronized with the rotational orbital motion of the lobe shaft, or a machine having a first axis, A plurality of radial reciprocating pistons arranged radially from a first axis; At a constant rate that is a predetermined rate of the first
Are configured to be rotatable about a corresponding second axis parallel to the axis of the lobe axis, and the plane of the lobe is substantially in the radial plane of the piston, and each piston has a rotational trajectory of the lobe axis. During reciprocation of the piston and the piston, maintains a substantially continuous contact with at least one lobe during each cycle of the reciprocation, defined by the period of time between contact and separation of each of the successive lobes with the piston. There is an almost lag-free transition between each successive reciprocating cycle of each piston, and the pistons are configured in pairs, with each pair of pistons maintaining their substantially asynchronous reciprocating motion. Machines that pump fluid from one to the other in response to piston reciprocating motion are referred to as "split cycle" machines.

[0004] The contents of the specifications of US Patent Nos. 5,146,880 and 5,279,209 are incorporated herein by reference. In the case of the configuration according to the invention, the output or input of the rotary machine takes place via the central rotary axis of the split-cycle machine.

DISCLOSURE OF THE INVENTION [0005] The present invention, which is described in connection with the operation of a split-cycle internal combustion engine, is described in WO96 / 3.
Obviously, it is also applicable to controlling the operation of a free piston engine as disclosed in 3343 or to controlling the pumping power of a piston interacting with a driven split cycle crank.

[0006] The arrangement of the lobes of the lobe shaft employed in the split cycle machine is hereinafter referred to as "Geneva gear".
And this lobe arrangement can be formed into a variety of profiles as contemplated by the disclosure of U.S. Pat. No. 5,146,880 and illustrated by FIG.

As shown in FIG. 5 of US Pat. No. 5,146,880, the lobes on the lobe shafts that make up the Geneva gear can have an outer shape that achieves asymmetric reciprocating motion with respect to the pistons, but each piston has It does not change the timing between top dead center (TDC) and bottom dead center (BDC) of movement. In contrast, the present invention, whether in the case of intake or exhaust or compression or expansion, optimizes the angular arrangement between the lobes of the Geneva gear to optimize each part of the operating cycle of a split-cycle engine. Alternately, a Geneva gear arrangement is provided in which the timing between top dead center and bottom dead center changes by facilitating changing the duration of each engine stroke. The non-conformal arrangement of the lobes in accordance with the present invention, combined with left-right asymmetrical contouring as disclosed in U.S. Pat. No. 5,146,880, allows for variations in the radial dimensions of the lobe peaks and valleys from the axis of the Geneva gear. In combination, the selection range of the timing and shape of each stroke of the engine cycle can be expanded.

It is clear that the invention is applicable to both four-stroke and two-stroke engines.

In embodiments of the present invention, the expansion stroke can be increased both in length and time to increase engine efficiency as compared to a conventional crank-operated internal combustion engine of equal stroke.

In essence, the same split cycle crank configuration fits different Geneva gear trains (fit) that can vary with respect to engine output performance to suit the application.
ment).

In a first embodiment of the known split cycle engine, US Pat. No. 5,279,209
The Geneva gear formed as a combination of the male type 10 and the female type 11 as shown in FIGS. 2 and 3 is used for exhaust or air supply and compression or expansion according to the port opening / closing timing diagram of FIG. You. This allows each Geneva gear group to have a specific shape and size.

The present invention seeks to improve the efficiency of at least part of the cycle of a split cycle engine.

The movement of each piston of the conventional split cycle engine is as shown in FIG.
Each part of the engine cycle can be optimized according to embodiments of the present invention. FIG. 2 shows a cycle in which four strokes of intake, compression, expansion, and exhaust occur in the same Geneva gear. The cycle shown in FIG. 2 needs to be modified for optimal engine performance. For example, if the combustion of the fuel is not fast, the piston movement during the expansion stroke is preferably relatively slow in the initial stage. By considering the desired characteristics of each stroke of the four-stroke cycle, it can be optimized for best engine performance.

FIG. 3 illustrates an optimal cycle different from the cycle shown in FIG. 2, and the cycle in FIG. 2 is indicated by a broken line in FIG.

From the optimum cycle of FIG. 3, it can be seen that it is appropriate to fill the combustion chamber as soon as possible. In the case of the compression stroke, it is desirable to delay the rise of the piston to minimize the negative torque.

Increasing the output of the optimal cycle as shown in FIG. 3 first increases the combustion time and expansion stroke, then flattens the combustion curve and flattens to a lesser extent at the top of the exhaust stroke. This can be achieved by doing Unfortunately, these two features
If the flattening of the expansion curve and the exhaust curve shown in FIG. 3 translates into a shortening of the expansion and the exhaust stroke, they act against one another.

Embodiments of the present invention relate to interlocking with the above constraints in improving the output of a split cycle engine by employing the non-conformal lobe arrangement described above, preferably in combination with asymmetric Geneva gear lobes. .

Furthermore, by giving a specific shape to the lower end of each piston, cycle efficiency can be further improved. By giving them different shapes,
One can correspond to exhaust or intake and the other to compression or expansion.

The shape of each lobe can be selected in a wide range for a two-stroke engine or a four-stroke engine. According to the invention, it is possible to select a unique "cycle" by changing the shape of the lobes and the associated angular arrangement.

Conventionally, a half male Geneva gear 10 and a half female Geneva gear 11 separated by a fixed half angle of 60 degrees as shown in FIG. 4 have been used.

In one embodiment, two gear groups of three Geneva gears are employed (for a 6 Geneva gear engine) at variable angular intervals.

In the prior art, the initial angular interval was uniformly 60 degrees.
It can be changed to 0 degrees or less. In fact, the cycle can be varied to increase engine efficiency. FIG. 2 shows a conventional symmetrical cycle.

Here, according to the present invention, the cycle shown in FIG. 5 can be established. The cycle of FIG. 5 has an expansion stroke and an expansion period longer than the conventional cycle, and can improve the efficiency as compared with the conventional cycle. Providing a stroke length change 12 between the intake or compression stroke and the expansion or exhaust stroke has a different profile between the female (for intake or exhaust) Geneva gear and the male (for compression or expansion) Geneva gear. Can be easily realized. The change of the travel period is realized by applying the present invention.

A conventional internal combustion engine has a known cycle of the shape shown in FIG. 6, where v is a dead volume and V is the total stroke volume. The above cycle is defined by the intake stroke 13, the compression stroke 14, the expansion stroke 15, and the exhaust stroke 16.

The volume ratio Σ is defined by the following equation. Σ = (v + V) / v For conventional fuels, 等 し く is equal to 11 and the theoretical thermodynamic efficiency ρ defined by
Is generated. ρ = 1-Σ ^-0.4 = 62%

The new cycle of FIG. 5 is illustrated by the PV diagram of FIG.

In the embodiment of FIG. 5, when the angular interval is 60 degrees, the theoretical efficiency is equal to 62%.

At an angular interval of 50 degrees, ρ = 70%, at an angular interval of 40 degrees, ρ = 77%, and at an angular interval of 30 degrees, ρ = 83%. It cannot be obtained with the split cycle engine of the conventional configuration.

In the present invention, the desired cycle can be selected, so that the overlapping of the intake port and the exhaust port can be minimized by the firing advance.

FIG. 8 shows an example of such a configuration, wherein denotes ignition advance, denotes intake advance, and denotes exhaust retard. Various types of split cycle engines can be implemented, for example, engines with four, six, eight, etc. Geneva gears.

Next, a method for optimizing the cycle by changing the length and the period of the expansion stroke will be described in further detail.

There are two ways to increase the length and duration of the expansion stroke.

The first is to change the shape of the Geneva gear, in which case the increase in length and duration of the expansion stroke is limited.

The second is to change the initial angular position of one Geneva gear group around the axis relative to the other Geneva gear group, so that a greater increase can be obtained. By using a particular shaped lobe, it is possible to optimize a particular cycle in which the initial angular position has been changed. One known form of the output crankshaft is shown in FIG.

According to one embodiment of the invention, the angle between the gears is maintained at 120 ° for a 6 Geneva gear engine. If it is necessary to increase the expansion stroke and increase engine efficiency, the gear and the angle β between α + β = 120 ° and α
It is appropriate to reduce the gears and the angles between them as shown in FIG. 10 as constrained by ≠ β; α <β. Finally, the geometry of the 6 Geneva gear engine will be as shown in FIG. That is, ++ is an exhaust or intake gear, and ++ is a compression or expansion gear.

If the angle between the male and female Geneva gears is less than 50 ° to 55 °, it may be difficult to use both gears in view of the resulting clearance. In this case, in the configuration shown in FIG. 11, two gear groups 20 each composed of three Geneva gears can be arranged and used in parallel as shown in FIG. In FIG. 11, the piston 60 is controlled by the Geneva gear group 20 which has a timing relationship with the planetary gear train 61 in the contact direction. A Geneva gear shaft 62 is mounted on a bearing support 63 connected to an output shaft 64.

A typical external shape of the intake or exhaust Geneva gear 30 according to the embodiment of the present invention is shown in FIG. 13, and a complementary compression or expansion Geneva gear 40 thereof is shown in FIG.

FIG. 15A shows the female exhaust or intake Geneva gear 50 in which the apex of the lobe 51 is located at the tip in the vertical direction in the initial orientation. The change in the direction of the lobe 51 in FIG. 15B is obtained by offsetting the lobe by an angle λ ° clockwise about the axis of the gear 50 with respect to the initial direction shown in FIG. is there. As a result of changing the initial angle direction between FIGS. 15A and 15B, the exhaust and intake strokes are shifted with respect to the rotation angle corresponding to the case of the conventional crank. This shift directly corresponds to the magnitude of λ.

The declination λ changes the radius R of the gear 50 to R ′, and the difference between the expansion or exhaust stroke and the intake or compression stroke is shown in FIG. 16 for the embodiment of FIG. Compensation for the loss of the length of the output or expansion stroke configured as described above.

The piston arrangement 70 shown in FIG. 17 includes a piston 71 connected to a lifter 73 via a piston rod 72. The contact surface 74 on the lifter 73 is molded and arranged to contact a female Geneva gear (not shown), and the contact surface 75 is molded and arranged to contact a male Geneva gear (not shown).

It will be apparent to those skilled in the art that various modifications and alterations can be made to the present invention described in the specific embodiments above without departing from the spirit or scope of the broadly described invention. Would. Therefore, it should be considered that the above embodiments are merely examples in all respects and do not limit the present invention.

[Brief description of the drawings]

FIG. 1 is a port opening / closing timing diagram of a conventional split cycle engine.

FIG. 2 is a piston motion diagram of a conventional split cycle engine.

FIG. 3 is a diagram corresponding to FIG. 2 (shown by broken lines) showing an ideal optimal four-stroke cycle;

FIG. 4 is a diagram showing a mutual relationship between two Geneva gear groups.

FIG. 5 is a diagram corresponding to FIG. 3 of one embodiment of the present invention.

FIG. 6 is a pressure volume diagram of a conventional internal combustion engine cycle.

FIG. 7 is a pressure volume diagram of the embodiment of FIG.

FIG. 8 is a view corresponding to FIG. 3, showing a result according to another embodiment of the present invention.

FIG. 9 is a schematic diagram showing the relationship between the output shaft and the Geneva gear of the configuration of FIGS. 1 and 2;

FIG. 10 is a schematic diagram corresponding to FIG. 9 of one embodiment of the present invention.

11 is a schematic diagram of the six Geneva gear engine of FIG.

FIG. 12 is a partial cross-sectional view of a split cycle engine incorporating one embodiment of the present invention.

FIG. 13 is a cross-sectional view of a Geneva gear for intake and exhaust according to an embodiment of the present invention.

14 is a sectional view of a Geneva gear for compression and expansion complementary to the gear of FIG.

FIGS. 15 (a) and (b) are views showing a female type having different initial directions, that is, a Geneva gear for exhaust / intake.

FIG. 16 is a view showing a movement effect of a piston between the gear of FIG. 15 (a) and the gear of FIG. 15 (b).

FIG. 17 is an isometric view showing one embodiment of a piston configuration of the split cycle machine according to the present invention.

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Claims (13)

[Claims] 1. A plurality of radial reciprocating pistons having a first axis and radially arranged from the first axis, and a plurality of circular pistons constrained to orbit around the first axis. And each lobe axis is configured to be rotatable about a corresponding second axis parallel to the first axis, and the lobe axis is fixed at a predetermined ratio of its orbital ratio. The lobe plane is substantially present in the radial plane of the piston, and each piston has its reciprocating motion and lobe during the rotational orbital motion of the lobe shaft and the reciprocating motion of the piston. A split-cycle machine connected to the at least one lobe so as to synchronize with a rotational orbital motion of a shaft, wherein a radial axis of each piston control lobe of the Geneva gear arrangement is the split-cycle machine. A split cycle machine which is arranged at an unequal angle with respect to the piston control lobes that are each before and after the machine is operated. 2. The split cycle machine according to claim 1, wherein each lobe of each Geneva gear is shaped symmetrically about a corresponding radial axis. 3. The split cycle machine according to claim 1, wherein each lobe of each Geneva gear is shaped asymmetrically about a corresponding radial axis. 4. A part of the lobe of the Geneva gear is formed symmetrically about the corresponding radial axis, and the remaining lobes of the Geneva gear are formed asymmetrically about the corresponding radial axis. The split cycle machine according to claim 1, wherein 5. The split cycle machine according to claim 1, wherein the split cycle machine is configured to operate as an internal combustion engine. 6. The split cycle machine according to claim 1, wherein the split cycle machine is configured to be linear with respect to a rotary motion converter connected to a free piston engine. 7. The Geneva gear comprises a male Geneva gear group and a female Geneva gear group, wherein the male Geneva gear group controls an expansion stroke and a compression stroke of at least one piston, and The split cycle machine according to any one of claims 1 to 6, wherein the Geneva gear group controls an intake stroke and an exhaust stroke of the at least one piston. 8. An engine incorporating the split cycle machine according to claim 5, wherein an expansion stroke and an exhaust stroke are longer than an intake stroke and a compression stroke. 9. The engine according to claim 8, wherein the period of the expansion stroke is longer than the period of the exhaust stroke. 10. The engine according to claim 9, wherein the length of the expansion stroke or the exhaust stroke is longer than the length of the intake stroke or the compression stroke. 11. A plurality of radial reciprocating pistons having a first axis and radially disposed from the first axis, and a plurality of circular reciprocating pistons constrained to orbit around the first axis. And each lobe axis is configured to be rotatable about a corresponding second axis parallel to the first axis, and the lobe axis is fixed at a predetermined ratio of its orbital ratio. The lobe plane is substantially present in the radial plane of the piston, and each piston has its reciprocating motion and lobe during the rotational orbital motion of the lobe shaft and the reciprocating motion of the piston. A method of controlling cylinder motion in a piston of a split-cycle machine connected to said at least one lobe so as to synchronize with rotational orbital motion of a shaft, the Geneva gear arrangement controlling piston motion. A method comprising the steps of varying the angular arrangement of lobe groups in a row so that the angular spacing between a pair of preceding and following piston control lobes is not equal. 12. The method according to claim 11, further comprising the step of varying the outer shape of the lobe of each Geneva gear so as to be bilaterally asymmetric with respect to the radial axis of each lobe. 13. A plurality of radial reciprocating pistons having a first axis and radially disposed from the first axis, and a plurality of circular reciprocating pistons constrained to orbit around the first axis. And each lobe axis is configured to be rotatable about a corresponding second axis parallel to the first axis, and the lobe axis is fixed at a predetermined ratio of its orbital ratio. The lobe plane is substantially present in the radial plane of the piston, and each piston has its reciprocating motion and lobe during the rotational orbital motion of the lobe shaft and the reciprocating motion of the piston. A group of Geneva gears of a split cycle machine connected to the at least one lobe so as to synchronize with the rotational orbital motion of the shaft, comprising a male Geneva gear mounted on the split cycle machine and a female gear. A group of Geneva gears, comprising a Geneva gear of a male type and a male and female Geneva gears, wherein radial axes of lobes which are arranged before and after the male and female Geneva gears are arranged at unequal angular intervals.