EP2484907B1 - Volume flow control - Google Patents

Description

The invention relates to a reciprocating engine according to the features standing in the preamble of claim 1.

Such reciprocating engines come in a structurally different design, for example as internal combustion engines or as a compressor used.

A generic state of the art is the DE 30 30 615 A1 , The known document discloses an internal combustion engine with at least one cylinder and a reciprocating piston therein, which is connected via a linkage with a crankshaft. The linkage comprises a hinged to the piston first connecting rod, a hinged to the crankshaft second connecting rod and a pivot lever which is articulated at one end about a crankshaft axis substantially parallel pivot axis and hingedly connected at its other end to the two connecting rods. The articulation point of the pivot lever should be arranged radially and / or axially adjustable and, for example, on a rotatably mounted eccentric. With the help of the known linkage, the course of the torque transmitted from the piston to the crankshaft and the course of the piston speed should be varied to a large extent.

However, a transfer of knowledge gained from internal combustion engines to compressors has not led to satisfactory results. Especially can be realized with the known features no continuous flow control.

Accordingly, the invention has for its object to provide a reciprocating engine with a continuous flow control while maintaining the predetermined space.

The object is achieved according to the invention with a reciprocating piston engine in the form of a compressor having first and second compression chambers separated by the piston, and the support via the adjusting mechanism between a position of the maximum rated stroke and a reduced stroke on at least a portion of a predetermined constant cross-section Center position is adjustable. The isoline represents a trajectory for the support.

The reciprocating piston engine according to the invention thus allows a continuous regulation of the delivery volume while maintaining the existing installation space with comparatively low construction costs. The crosshead center position is understood to mean a position of the piston corresponding to its half stroke.

The link eliminates an additional degree of freedom of the crank mechanism and determines with its bearing point the stroke of the piston and the crosshead center position. In an adjustment of the armature and concomitant reduction in the piston stroke, if the adjustment takes place at a constant crosshead center position, the dead space on both sides increased by the same amount, that is, the piston no longer performs the maximum nominal stroke, but only a reduced Hub within the cylinder. In this case, compliance with the crosshead center position is of great importance, since otherwise the dead space is not changed by the same amount on both sides of the piston. Experience has shown that with such devices is a larger Flywheel necessary. In addition, the load change characteristics of the crosshead bearing pin is adversely affected in different sized dead zones and it is also to be assumed by an increased inducing harmonic oscillations in subsequent gas chambers and caused by an increased tendency to resonance formation.

Conveniently, the support comprises a linkage bearing, with which the linkage member rotatably engages the support.

Advantageously, the upper connecting rod, the lower connecting rod and the Anlenker form a ternary joint. At the ternary joint both the upper and lower connecting rods and the link arms rotate in a common point or a common bearing axis. The essential advantage of this embodiment is that in the support of the armature the lowest expected Anlenkerkraft occurs.

A trained with the ternary joint compressor can be designed for example on the basis of a numerical solution. In this case, first of all a rectangular area is defined, which comprises the area suitable for accommodating the articulated arm support E (installation space condition). This rectangular area is then provided with a screening, wherein the points of the grid correspond to the respective position of the armature support E.

und $$y_{\mathrm{C},\mathrm{Tot}}=y_{\mathrm{KW}}+\frac{y_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{l_4}^2+{l_{\mathrm{KWE}}}^2\right)+k_1{x}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{KWE}}}^4+2{\left({l_{\mathrm{T}}}^2+{l_4}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{l_4}^2\right)}^2}}{2{l_{\mathrm{KWE}}}^2}$$

mit $$x_{\mathrm{KWE}}=x_{\mathrm{E}}-x_{\mathrm{KW}},y_{\mathrm{KWE}}=y_{\mathrm{E}}-y_{\mathrm{KW}},{l_{\mathrm{KWE}}}^2+{y_{\mathrm{KWE}}}^2\mathrm{und}{k}_1\in \left\{-1;1\right\}$$

und $l_{\mathrm{T}}=\{\begin{array}{c}\mathrm{OT}:l_2+r_{\mathrm{KW}}\\ \mathrm{UT}:l_2-r_{\mathrm{KW}}\end{array}$

berechenbar ist, wobei sich der jeweilige obere und untere Totpunkt (OT, UT) aus $$y_{\mathrm{KK},\mathrm{Tot}}=k_2\sqrt{{l_3}^2-{\left(x_{\mathrm{KK}}-x_{\mathrm{C},\mathrm{Tot}}\right)}^2}+y_{\mathrm{C},\mathrm{Tot}}$$

mit k ₂ ∈ {-1;1} ergibt und die Kreuzkopf-Mittellage (y_KK,Mittel) durch Einsetzen in die Gleichung $$y_{\mathrm{KK},\mathrm{Mittel}}=\frac{y_{\mathrm{KK},\mathrm{OT}}+y_{\mathrm{KK},\mathrm{UT}}}{2}$$

definiert ist.Then, for each of these grid points, the dead-center of the four-joint KW-BCE can be identified. These are given in the extended position or cover layer of crank and lower connecting rod according to $$x_{\mathrm{C}.\mathrm{Dead}}=x_{\mathrm{KW}}+\frac{x_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4}^2+{l_{\mathrm{KWE}}}^2\right)-{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="imgf0003.png"\; state="\{\{state\}\}">k</figure-callout>}}_1{y}_{\mathrm{KWE}}\sqrt{-{{\mathrm{<figure-callout\; id="4"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^4+2{\left({{\mathrm{<figure-callout\; id="2"\; label="l\; T"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{T}}}^2+{{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4}^2\right)}^2}}{2{{\mathrm{<figure-callout\; id="2"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^2}$$

and $$y_{\mathrm{C}.\mathrm{Dead}}=y_{\mathrm{KW}}+\frac{y_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4}^2+{{\mathrm{<figure-callout\; id="2"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^2\right)+k_1{x}_{\mathrm{KWE}}\sqrt{-{{\mathrm{<figure-callout\; id="4"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^4+2{\left({{\mathrm{<figure-callout\; id="2"\; label="l\; T"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{T}}}^2+{{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4}^2\right)}^2}}{2{{\mathrm{<figure-callout\; id="2"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^2}$$

With $$x_{\mathrm{KWE}}=x_{\mathrm{e}}-x_{\mathrm{KW}}.y_{\mathrm{KWE}}=y_{\mathrm{e}}-y_{\mathrm{KW}}.{{\mathrm{<figure-callout\; id="2"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^2+{{\mathrm{<figure-callout\; id="2"\; label="y\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">y\; </figure-callout>}}_{\mathrm{KWE}}}^2\mathrm{and}{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="imgf0003.png"\; state="\{\{state\}\}">k</figure-callout>}}_1\in \left\{-1;1\right\}$$

and $l_{\mathrm{T}}=\{\begin{array}{c}\mathrm{OT}:{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_2+r_{\mathrm{KW}}\\ \mathrm{UT}:l_2-r_{\mathrm{KW}}\end{array}$

is calculable, with the respective top and bottom dead center (OT, UT) of $$y_{\mathrm{KK}.\mathrm{Dead}}={\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\sqrt{{{\mathrm{<figure-callout\; id="3"\; label="l"\; filenames="imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_3}^2-{\left(x_{\mathrm{KK}}-x_{\mathrm{C}.\mathrm{Dead}}\right)}^2}+y_{\mathrm{C}.\mathrm{Dead}}$$

with k ₂ ∈ {-1; 1} and the crosshead center position (y _{KK, mean} ) by inserting into the equation $$y_{\mathrm{KK}.\mathrm{medium}}=\frac{y_{\mathrm{KK}.\mathrm{OT}}+y_{\mathrm{KK}.\mathrm{UT}}}{2}$$

is defined.

The calculations are geometrically interpretable: The position of the joint C in the dead spots follows from the intersection of the radius with the radius I _T = I ₂ ± r _K around the crankshaft and the circumference with the radius I ₄ around the support E. The position of the Joint D with the coordinates x _KK / y _KK follows from the intersection between the Radius of radius I ₃ around C with the output axis. The determination of one of the two intersections generated in this way is done via the position parameters k ₁ and k ₂ .

Preferably, the bearing axis of the arranged between the upper connecting rod and crosshead piston-side connecting rod bearing, the bearing axis of the arranged between the lower connecting rod and crank pin crankshaft side connecting rod bearing, the bearing axis of a ternary joint and the bearing axis of a Anlenker bearing are arranged parallel to each other. Consequently, it is with the inventive arrangement of the bearings to a flat gear.

und $$y_{\mathrm{C}1,\mathrm{Tot}}=y_{\mathrm{KW}}+\frac{y_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{l_{41}}^2+{l_{\mathrm{KWE}}}^2\right)+k_1{x}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{KWE}}}^4+2{\left({l_{\mathrm{T}}}^2+{l_{41}}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{l_{41}}^2\right)}^2}}{2{l_{\mathrm{KWE}}}^2}$$

mit x _KWE = x _E - x _KW, y _KWE = y _E - y _KW, l _KWE ² = x _KWE ² + y _KWE ² bei k ₁ ∈{-1;1} und $l_{\mathrm{T}}=\{\begin{array}{c}\mathrm{OT}:l_2+r_{\mathrm{KW}}\\ \mathrm{UT}:l_2-r_{\mathrm{KW}}\end{array}$

berechenbar ist, wobei sich der jeweilige obere und untere Totpunkt (OT, UT) aus $$y_{\mathrm{KK},\mathrm{Tot}}=y_{\mathrm{E}}+k_2\sqrt{{l_3}^2-{\left(x_{\mathrm{KK}}-x_{\mathrm{E}}-\frac{l_{42}}{l_{42}}\left[{\left(x_{\mathrm{C}1,\mathrm{Tot}}-x_{\mathrm{E}}\right)}^2\cos \tau -{\left(y_{\mathrm{C}1,\mathrm{Tot}}-y_{\mathrm{E}}\right)}^2\sin \tau \right]\right)}^2}+\frac{l_{42}}{l_{42}}\left[{\left(x_{\mathrm{C}1,\mathrm{Tot}}-x_{\mathrm{E}}\right)}^2\sin \tau +{\left(y_{\mathrm{C}1,\mathrm{Tot}}-y_{\mathrm{E}}\right)}^2\cos \tau \right]$$

mit k ₂ ∈ {-1;1} ergibt und die Kreuzkopf-Mittellage (y_KK,Mittel) durch Einsetzen in die Gleichung $$y_{\mathrm{KK},\mathrm{Mittel}}=\frac{y_{\mathrm{KK},\mathrm{OT}}+y_{\mathrm{KK},\mathrm{UT}}}{2}$$

definiert ist.According to an alternative embodiment, the lower connecting rod and the upper connecting rod engage at spaced bearing points of a ternary Anlenkers. The ternary Anlenker thus has three bearings, which form a triangle to each other, wherein a first bearing point with the support, a second bearing point with the lower connecting rod and a third bearing point is connected to the upper connecting rod. The determination of the dead-spots can be carried out according to the aforementioned embodiment, wherein $$x_{\mathrm{C}1.\mathrm{Dead}}=x_{\mathrm{KW}}+\frac{x_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="41"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{41}}^2+{l_{\mathrm{KWE}}}^2\right)-{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="imgf0003.png"\; state="\{\{state\}\}">k</figure-callout>}}_1{y}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{<figure-callout\; id="4"\; label="KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">KWE</figure-callout>}}}^4+2{\left({l_{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">T</figure-callout>}}}^2+{{\mathrm{<figure-callout\; id="41"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{41}}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="41"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{41}}^2\right)}^2}}{2{{\mathrm{<figure-callout\; id="2"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^2}$$

and $$y_{\mathrm{C}1.\mathrm{Dead}}=y_{\mathrm{KW}}+\frac{y_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="41"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{41}}^2+{{\mathrm{<figure-callout\; id="2"\; label="l\; KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l\; </figure-callout>}}_{\mathrm{KWE}}}^2\right)+k_1{x}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{<figure-callout\; id="4"\; label="KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">KWE</figure-callout>}}}^4+2{\left({l_{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">T</figure-callout>}}}^2+{{\mathrm{<figure-callout\; id="41"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{41}}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{{\mathrm{<figure-callout\; id="41"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{41}}^2\right)}^2}}{2{l_{\mathrm{<figure-callout\; id="2"\; label="KWE"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">KWE</figure-callout>}}}^2}$$

with x _KWE = x _E - x _KW , y _KWE = y _E - y _KW , l _KWE ² = x _KWE ² + y _KWE ² at k ₁ ∈ {-1; 1} and $l_{\mathrm{T}}=\{\begin{array}{c}\mathrm{OT}:{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_2+r_{\mathrm{KW}}\\ \mathrm{UT}:l_2-r_{\mathrm{KW}}\end{array}$

is calculable, with the respective top and bottom dead center (OT, UT) of $$y_{\mathrm{KK}.\mathrm{Dead}}=y_{\mathrm{e}}+{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\sqrt{{{\mathrm{<figure-callout\; id="3"\; label="l"\; filenames="imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_3}^2-{\left(x_{\mathrm{KK}}-x_{\mathrm{e}}-\frac{l_{42}}{{\mathrm{<figure-callout\; id="42"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{42}}\left[{\left(x_{\mathrm{C}1.\mathrm{Dead}}-x_{\mathrm{e}}\right)}^2\cos \tau -{\left(y_{\mathrm{C}1.\mathrm{Dead}}-y_{\mathrm{e}}\right)}^2\sin \tau \right]\right)}^2}+\frac{l_{42}}{{\mathrm{<figure-callout\; id="42"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}_{42}}\left[{\left(x_{\mathrm{C}1.\mathrm{Dead}}-x_{\mathrm{e}}\right)}^2\sin \tau +{\left(y_{\mathrm{C}1.\mathrm{Dead}}-y_{\mathrm{e}}\right)}^2\cos \tau \right]$$

with k ₂ ∈ {-1; 1} and the crosshead center position (y _{KK, mean} ) by inserting into the equation $$y_{\mathrm{KK}.\mathrm{medium}}=\frac{y_{\mathrm{KK}.\mathrm{OT}}+y_{\mathrm{KK}.\mathrm{UT}}}{2}$$

is defined.

Preferably, it is checked before determining the crosshead center position, whether the link (reference numerals of Figure description 4, or ternary link 42) during movement between the stretch or cover layer of crank and lower connecting rod itself a stretch or cover layer with the upper Connecting rod occupies. If this is not the case, the layers from the above-exemplified calculation also describe the dead spots of the crosshead. Otherwise, a crosshead dead center is given by the extended position of link (4, or ternary link 42) and upper connecting rod and the other given by one of the layers from the above calculation.

In further embodiments, the lower connecting rod or the upper connecting rod may be formed in each case as a ternary connecting rod.

In a particularly favorable embodiment, the positioning mechanism comprises a linear guide with a stationarily arranged rail and a slidably engaging carriage, wherein the support is arranged on the carriage and the alignment of the adjusting mechanism is approximated as an approximation to the portion of an isoline of the constant crosshead center position. This embodiment represents a technically simple implementation of the teaching according to the invention, the accuracy of which is sufficient for operation in practice. The adjusting mechanism or the associated linear guide is already aligned in the production of the compressor according to the known coordinates of the isoline and fixedly mounted on the compressor.

On the carriage can engage a linear drive whose adjustment is aligned parallel to the axial extent of the rail. As a linear drive in particular form-locking lockable elements, racks can be used with complementarily arranged on the carriage gears or threaded spindles used. According to a particularly advantageous embodiment, the linear drive comprises a hydraulic cylinder, which is held stationary with a first end and secured with its second, opposite end to the carriage.

Conveniently, the linear guide is oriented at an angle (α) between 0 ° and 45 ° inclined to the axis of movement of the piston.

Fig. 1:

eine schematische Ansicht auf einen erfindungsgemäßen Verdichter gemäß einer ersten Ausführungsform;

Fig. 2:

eine schematische Ansicht auf einen erfindungsgemäßen Verdichter gemäß einer zweiten Ausführungsform;

Fig. 3:

Berechnung von Isolinien mittels Line-following-Algorithmus;

Fig. 4:

ein Feld von Isolinien konstanter mittlerer Kreuzkopflagen;

Fig. 5:

einen Längsschnitt auf den Verdichter gemäß Fig. 1 mit linearer Approximation der Isolinie und Linearführung des Auflagers sowie

Fig. 6:

eine schematische Darstellung des Verdichters gemäß Fig. 5.

For a better understanding of the invention will be explained below with reference to a total of six figures. The show

Fig. 1:

a schematic view of a compressor according to the invention according to a first embodiment;

Fig. 2:

a schematic view of a compressor according to the invention according to a second embodiment;

3:

Calculation of isolines using the line-following algorithm;

4:

a field of isolines of constant central crossheads;

Fig. 5:

a longitudinal section of the compressor according to Fig. 1 with linear approximation of the isoline and linear guidance of the support as well

Fig. 6:

a schematic representation of the compressor according to Fig. 5 ,

The Fig. 1 shows a schematic view of a reciprocating compressor according to the invention according to a first embodiment with a ternary joint C, to which a connecting rod 1 comprising a lower connecting rod 2 and an upper connecting rod 3 and an armature 4 attack together. In this case, a crank K formed on a crankshaft KW with its crankpin B and the crankshaft-side connecting rod bearing L _P2 arranged thereon sets a rotational movement corresponding to the crank angle φ of the crankshaft KW via the lower connecting rod 2 and the upper connecting rod 3 in an oscillating linear movement of one end on the upper connecting rod 3 arranged piston KO. The upper connecting rod 3 engages with a piston-side connecting rod bearing L _P1 at the crosshead KK of the piston KO. The piston KO moves during operation of the compressor within the movement axis fourteenth

The link 4 extends from the ternary joint C to a laterally offset from the movement axis 14 of the piston KO armature bearing 4a a support E.

The spatial position of the crankshaft KW or its centric axis is defined via its coordinates x _KW / y _KW , the position of the crosshead KK via its coordinates x _KK / y _KK and that of the support E via the coordinates x _E / y _E. The illustrated embodiment of the compressor has a so-called centric sliding crank, in which the extension of the movement axis 14 extends through the crankshaft axis perpendicular to it, wherein the invention is basically also on compressors with eccentric arrangement of the crank handle feasible.

Dotted in the region of the support E are two intersecting isolines of a maximum nominal stroke H _{max of} the piston KO, wherein in the shown state of the compressor the support E is located on the substantially vertical characteristic of a maximum rated stroke H _{max of} the piston KO. At the maximum nominal stroke H _max , the piston KO moves on the movement axis 14 between its top dead center OT and its bottom dead center UT. Between the top and bottom dead center OT, UT is the crosshead center location y _{KK, means} . It remains within the in Fig. 1 not completely shown cylinder or arranged on both sides of the piston KO first and second compression chamber 6, 7 (see Fig. 5 ) a minimal dead space. Since it is a compressor with a centrally arranged thrust crank, the x coordinates of the crosshead KK also correspond to the x coordinates of the crankshaft x _KW .

In addition, in the presentation of the Fig. 1 with dashed line a family of curves of isolines of constant crosshead center layers y _{KK, means} to detect. According to the teaching of the invention for adjusting the flow rate of the compressor the support E is displaced on an isoline of constant crosshead center position and simultaneously moved out of its position of the maximum rated lift H _max . By way of example, a position of a reduced stroke H _{min is marked} on the corresponding isoline of a constant crosshead center position y _{kk, means} . In this position of the support E of the piston KO continues to perform an alternating movement about its central position y _{KK, means} , but at significantly increased dead space in the respective compression chambers 6, 7 (see Fig. 5 ) and a reduced stroke and a resulting reduced delivery volume.

For an increase in the delivery volume, the support E is moved from the exemplarily marked position H _min back on the isoline of a constant crosshead center position y _{KK, means} to the point of intersection with the isoline of the maximum nominal stroke H _max . Likewise, an adjustment in each point between H _min and H _{max is} possible.

The Fig. 2 shows an alternative embodiment of the compressor with a ternary link instead of a ternary joint C, in which attack the lower connecting rod 2 at a bearing point C1 and the upper connecting rod 3 at a bearing point C1 spaced bearing point C2. The bearing C1 and the support E of the ternary Anlenkers define one side 41 and the bearing C2 and the support E a second side 42. The bearings C1, C2, E thus form a triangle. Furthermore, the sides 41, 42 adjacent to the support E span the angle τ.

The adjustment of the delivery volume takes place in this embodiment with a ternary Anlenker by adjusting the support E on a in Fig. 2 Not shown isoline (see Fig. 1 ) of a constant crosshead center position y _{KK, means} with simultaneous removal of the isoline of a maximum nominal stroke H _max .

For example, the calculation of the isoline of the desired crosshead center location y _{KK, mean} may be based on Snyder's line-following algorithm, which is for a gridline in Fig. 3 is shown.

Accordingly, as part of the calculation, the raster is traversed line by line in a first step and the edges of each raster cell are examined for intersections with isolines. Such an intersection exists when a searched iso value lies between the parameter values of the two halftone dots involved.

der y-Koordinate analog. Zusätzlich wird vermerkt, dass der Isowert auf der aktuellen Gitterkante erkannt wurde, damit dieser Schritt nicht wiederholt wird.If such a grating edge has been found, in a second step the intersection P _{section of} the isoline with the edge is determined by linear interpolation of the parameter value w (0 ≦ w ≦ 1) between the start and end points of the edge. The calculation of the x- coordinate takes place after $$x_{\mathrm{cut}}=x_{\mathrm{begin}}+\left(x_{\mathrm{End}}-x_{\mathrm{begin}}\right)\cdot \frac{w_{\mathrm{cut}}-w_{\mathrm{begin}}}{w_{\mathrm{End}}-w_{\mathrm{begin}}}.$$

the y-coordinate analog. In addition, it is noted that the iso value has been recognized on the current grid edge so that this step is not repeated.

Subsequently, in a third step, the grid cell adjacent to the current grid edge, that is to say the edge on which the intersection with an isoline has been found, is examined for another intersection with the current isoline. Once this edge is found, the point of intersection is determined and the two intersection points are connected with a straight line.

The above steps should then be repeated until all of the grid edges intersecting with the sought-for isoline are already marked for them.

mit l _max ∈ {l ₂ ; l ₄} und l'∈ {l ₂; l ₄} \ l _max In practicable solutions, the four-bar linkage KW-BCE forms a rocker arm, in which the crank rotates and the link swings. Based on the set by Grashof, the permissible positions of the linkage bearing E can be limited for these gear units. The geometric quantities must satisfy the following equation, with the respective lengths in the Fig. 1 are shown: $$\begin{array}{l}\left(l_{\mathrm{KWE}}=l_{\mathrm{Max}}\wedge r_{\mathrm{KW}}+l_{\mathrm{KWE}}>{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_2+{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4\right)\\ \vee \left(l_{\mathrm{KWE}}\ne l_{\mathrm{Max}}\wedge r_{\mathrm{KW}}+l_{\mathrm{Max}}>l_{\mathrm{KWE}}+\mathit{l\text{'}}\right)\end{array}$$

with l _max ∈ { l ₂ ; l ₄ } and l ' ∈ { l ₂ ; l ₄ } \ l _max

This is the case if the distance between the crank axle and the armature support fulfills the following condition: $$\left|l_2-{\mathrm{<figure-callout\; id="4"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_4\right|+r_{\mathrm{KW}}<l_{\mathrm{KWE}}<{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">l</figure-callout>}}_2+l_4-r_{\mathrm{KW}}$$

From the condition of the above equation, it is apparent that all valid solutions by armature bearing positions between two circles with the radii corresponding to the upper and lower limits from this above equation around the crankshaft axis, respectively Fig. 4 Marked are.

The Fig. 4 also shows the relevant for the determination of the crosshead center positions y _{KK, means} relevant parameters, such as the radius of the crankshaft r _K (sometimes also referred to as r _KW ), the length I _{2 of} the lower connecting rod 2, the length I _{3 of} the upper connecting rod. 3 , the length I _{4 of} the armature 4, which also each of the Fig. 1 can be removed. The coordinates x _a , y _{a of} the crankshaft axis KW (also denoted by x _KW and y _KW ) corresponding to the origin of the in the FIGS. 1, 2 and 6 recognizable coordinate cross and are therefore set to 0.

Consequently, in the case of the underlying compressor with centric push crank, the offset of the crosshead in the x direction corresponding to x _D (also denoted by x _KK ) must also assume the value 0.

In the FIGS. 5 and 6 is a compressor with a linearly displaceable support E shown. The displacement of the support E takes place by means of an adjusting mechanism 5 in the form of a linear guide 8. The linear guide 8 comprises a rail 9 and a carriage 10 movably guided on it, which carries the support E and is infinitely movable via a linear drive 11. The in Fig. 6 shown adjustment 12 and the orientation of the linear guide 8 are approximately adapted to an isoline of the constant crosshead center layers y _{KK, medium} . The selection of an isoline from the family of curves of isolines takes place in particular in consideration of the available installation space.

As a linear drive 11 comes due to its suitability, even large forces transmitted and also to be able to approach each position of the adjustment infinitely, in particular a hydraulic cylinder 13 into consideration. The hydraulic cylinder 13 is fixedly attached to the compressor at its first end 13a and to the carriage 10 at its second end 13b.

Like in the Fig. 6 can be seen, the rail 9 is parallel to the dotted line "approximation" and at an angle α to the movement axis 14 of the piston KO. The relevant isoline of a constant crosshead center position y _{KK, means} deviates from the "approximation" or the alignment of the rail 9 in the selected region only in a central convex-shaped section.

LIST OF REFERENCE NUMBERS

1

pleuel

2

lower connecting rod

3

upper connecting rod

4

Anlenker

4a

Anlenker camp

5

mechanism

6

first compression chamber

7

second compression chamber

8th

linear guide

9

rail

10

carriage

11

linear actuator

12

Adjustment linear drive

13

hydraulic cylinders

13a

first end of hydraulic cylinder

13b

second end hydraulic cylinder

14

Movement axis piston

41

Side of ternary link between E and C1

42

Side of ternary link between E and C2

B

Crankpin crankshaft

C

ternary joint

C1

Bearing point lower connecting rod / linkage

C2

Bearing point upper connecting rod / linkage

e

In stock

H _max

maximum rated stroke

H _min

reduced stroke

K

crank

KK

Phillips

KO

piston

KW

Crankshaft (crank axle)

I ₂

Length of lower connecting rod

I ₃

Length of upper connecting rod

I ₄

Length of link

I _KWE

Distance crankshaft to support E

L _P1

piston-side connecting rod bearing

L _P2

kurbeiwellenseitiges connecting rod bearing

OT

Top Dead Center

UT

bottom dead center

r _K / r _KW

Radius crankshaft

x _A / y _A

Coordinates crankshaft axis (= x _KW / y _KW )

x _D

x-coordinate crosshead (= x _KK )

x _E / y _E

Coordinates of the linkage support

x _KK / y _KK

Coordinates of the crosshead (downforce)

x _KW / y _KW

Coordinates of the driving crankshaft (crank axle)

y _{KK, means}

Phillips-center position

α

Angle approximated isoline / axis of motion piston

φ

crank angle

τ

Angle between pages 41, 42

Claims (12)

1. Reciprocating piston engine having a steplessy adjustable delivery volume, comprising a piston (KO), a divided connecting rod arrangement (1) which engages thereon and which has a lower and an upper connecting rod (2, 3) and a link (4), wherein the upper connecting rod (3) engages on a crosshead (KK) of the piston (KO) and on the link (4), the lower connecting rod (2) connects the link (4) to a crank pin (B) of a crankshaft (KW) and the link (4) has at the end thereof opposite the connecting rods (2, 3) a bearing (E) which cooperates with an adjustment mechanism (5),
   characterised in that
   the reciprocating piston engine is a compressor which has first and second compression chambers (6, 7) which are separated by the piston (KO) and the bearing (E) can be adjusted by means of the adjustment mechanism (5) between a position of maximum nominal stroke (H_max) and a reduced stroke (H_min) on at least one portion of a predetermined isoline of the constant crosshead central position.
2. Reciprocating piston engine according to claim 1, characterised in that the bearing (E) comprises a link bearing (4a) by means of which the link (4) engages on the bearing (E) in a rotationally movable manner.
3. Reciprocating piston engine according to claim 1 or claim 2, characterised in that the lower connecting rod (2), the upper connecting rod (3) and the link (4) are connected in a rotationally movable manner by means of a ternary articulation (C).
4. Reciprocating piston engine according to claim 3, characterised in that, for each location of the bearing (E) that can be changed by the adjustment mechanism (5), the cross-head central position (y_kk,Mittel) can be calculated from the identification of the dead-centre positions of the four-link system KW-B-C-E in the extended position or covering position of the crank (K) and lower connecting rod (2) in accordance with $$x_{\mathrm{C},\mathrm{Tot}}=x_{\mathrm{KW}}+\frac{x_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{l_4}^2+{l_{\mathrm{KWE}}}^2\right)-k_1{y}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{KWE}}}^4+2{\left({l_{\mathrm{T}}}^2+{l_4}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{l_4}^2\right)}^2}}{2{l_{\mathrm{KWE}}}^2}$$

   

   
   and $$y_{\mathrm{C},\mathrm{Tot}}=y_{\mathrm{KW}}+\frac{y_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{l_4}^2+{l_{\mathrm{KWE}}}^2\right)+k_1{x}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{KWE}}}^4+2{\left({l_{\mathrm{T}}}^2+{l_4}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{l_4}^2\right)}^2}}{2{l_{\mathrm{KWE}}}^2}$$

   

   
   x _KWE = x _E - x _KW, y _KWE = y _E - y _KW, l _KW ² = x _KWE ² + y _KWE ², with for
   k ₁ ∈ {-1;1} $l_{\mathrm{T}}=\{\begin{array}{c}\mathrm{OT}:l_2+r_{\mathrm{KW}}\\ \mathrm{UT}:l_2-r_{\mathrm{KW}}\end{array},$

   

   
   and , wherein the respective upper and lower dead-centre position (OT, UT) is produced from $$y_{\mathrm{KK},\mathrm{Tot}}=k_2\sqrt{{l_3}^2-{\left(x_{\mathrm{KK}}-x_{\mathrm{C},\mathrm{Tot}}\right)}^2}+y_{\mathrm{C},\mathrm{Tot}}$$

   

   
   with k ₂ ∈ {-1;1} and the crosshead central position (y _kk,Mittel) being defined by insertion into the equation $$y_{\mathrm{KK},\mathrm{Mittel}}=\frac{y_{\mathrm{KK},\mathrm{OT}}+y_{\mathrm{KK},\mathrm{UT}}}{2}$$

   
5. Reciprocating piston engine according to claim 3 or 4, characterised in that the bearing axle of the piston-side connecting rod bearing (L_P1) which is arranged between the upper connecting rod (3) and crosshead (KK), the bearing axle of the crankshaft-side connecting rod bearing (L_P2) which is arranged between the lower connecting rod (2) and the crankpin (B), the bearing axle of the ternary articulation (C) and the bearing axle of the link bearing (4a) are arranged parallel with each other.
6. Reciprocating piston engine according to claim 1 or claim 2, characterised in that the lower connecting rod (2) and the upper connecting rod (3) engage at mutually spaced-apart bearing locations (C1, C2) of the ternary link (4).
7. Reciprocating piston engine according to claim 6, characterised in that, for each location of the bearing (E) that can be changed by the adjustment mechanism (5), the crosshead central position (y_kk,Mittel) can be calculated from the identification of the dead-centre positions of the four-link system KW-B-C1-E in the extended position or covering position of the crank (K) and lower connecting rod (2) in accordance with $$x_{\mathrm{C}1,\mathrm{Tot}}=x_{\mathrm{KW}}+\frac{x_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{l_{41}}^2+{l_{\mathrm{KWE}}}^2\right)-k_1{y}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{KWE}}}^4+2{\left({l_{\mathrm{T}}}^2-{l_{41}}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{l_{41}}^2\right)}^2}}{2{l_{\mathrm{KWE}}}^2}$$

   

   
   and $$y_{\mathrm{C}1,\mathrm{Tot}}=y_{\mathrm{KW}}+\frac{y_{\mathrm{KWE}}\left({l_{\mathrm{T}}}^2-{l_{41}}^2+{l_{\mathrm{KWE}}}^2\right)+k_1{x}_{\mathrm{KWE}}\sqrt{-{l_{\mathrm{KWE}}}^4+2{\left({l_{\mathrm{T}}}^2+{l_{41}}^2\right)}^2{l_{\mathrm{KWE}}}^2-{\left({l_{\mathrm{T}}}^2-{l_{41}}^2\right)}^2}}{2{l_{\mathrm{KWE}}}^2}$$

   

   
   x _KWE = x _E - x _KW, y _KWE = y _E - y _KW, l _KWE ² = x _KWE ² + y _KWE ² with
   for k ₁∈{-1;1} and $l_{\mathrm{T}}=\{\begin{array}{c}\mathrm{OT}:l_2+r_{\mathrm{KW}}\\ \mathrm{UT}:l_2-r_{\mathrm{KW}}\end{array},$

   

   wherein the respective upper and lower dead-centre position (OT, UT) is produced from $$y_{\mathrm{KK},\mathrm{Tot}}=y_{\mathrm{\epsilon }}+k_2\sqrt{{l_3}^2-{\left(x_{\mathrm{KK}}-x_{\mathrm{E}}-\frac{l_{42}}{l_{42}}\left[{\left(x_{\mathrm{C}1,\mathrm{Tot}}-x_{\mathrm{E}}\right)}^2\cos \tau -{\left(y_{\mathrm{C}1,\mathrm{Tot}}-y_{\mathrm{E}}\right)}^2\sin \tau \right]\right)}^2}+\frac{l_{42}}{l_{42}}\left[{\left(x_{\mathrm{C}1,\mathrm{Tot}}-x_{\mathrm{E}}\right)}^2\sin \tau +{\left(y_{\mathrm{C}1,\mathrm{Tot}}-y_{\mathrm{E}}\right)}^2\cos \tau \right]$$

   

   
   k ₂ ∈ {-1;1}
   with and the crosshead central position (Y_KK,Mittel) being defined by means of insertion into the equation $$y_{\mathrm{KK},\mathrm{Mittel}}=\frac{y_{\mathrm{KK},\mathrm{OT}}+y_{\mathrm{KK},\mathrm{UT}}}{2}$$

   
8. Reciprocating piston engine according to claim 6 or claim 7, characterised in that the bearing axle of the piston-side connecting rod bearing (L_P1) which is arranged between the upper connecting rod (3) and crosshead (KK), the bearing axle of the crankshaft-side connecting rod bearing (L_P2) which is arranged between the lower connecting rod (2) and the crankpin (B), the bearing axle of the bearing location (C1) which is arranged between the lower connecting rod (2) and the link (4) and the bearing location (C2) which is arranged between the upper connecting rod (3) and link (4) and the bearing axle of a link bearing (4a) are arranged parallel with each other.
9. Reciprocating piston engine according to any one of claims 1 to 8, characterised in that the adjustment mechanism (5) comprises a linear guide (8) having a fixedly arranged rail (9) and a sliding member (10) which engages thereon, wherein the bearing (E) is arranged on the sliding member (10) and the orientation of the adjustment mechanism (5) as an approximation is moved closer to the portion of an isoline of the constant crosshead central location (Y_KK,Mittel).
10. Reciprocating piston engine according to claim 9, characterised in that there engages on the sliding member (10) a linear drive (11) whose adjustment path (12) is orientated parallel with the axial extent of the rail (9).
11. Reciprocating piston engine according to claim 10, characterised in that the linear drive (11) comprises a hydraulic cylinder (13) which is retained in a fixed manner with a first end (13a) and which is secured with the second opposing end (13b) thereof to the sliding member (10).
12. Reciprocating piston engine according to any one of claims 9 to 11, characterised in that the linear guide (8) is orientated at an angle (α) between 0° and 45° in a state inclined relative to the movement axis (14) of the piston (KO).

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