WO1994004799A1

WO1994004799A1 - Regulating slide-valve gear

Info

Publication number: WO1994004799A1
Application number: PCT/CZ1993/000020
Authority: WO
Inventors: Frantisek Novák
Original assignee: Prewetool Ag
Priority date: 1992-08-11
Filing date: 1993-08-10
Publication date: 1994-03-03
Also published as: AU4941293A; CZ247892A3

Abstract

A regulating slide-valve gear, especially for an asymmetrical timing of two-stroke engine. In the regulating slide-valve gear a driving element of an epicyclic gear (1) engages the engine crankshaft and at the same time via a controlled element (4) a driven element of the epicyclic gear (1) which is connected by a gearing with at least one slide-valve shaft (6) of a turning slide valve (7) mounted rotatable within a slide-valve housing (8) arranged in the engine port (C). The controlled element (4) of the epicyclic gear (1) is connected to a regulating element of a control device (3) the electrical input of which is connected with a sensing and regulating unit (2) established for sensing actual parameters of the engine and regulating mutual angular positions of the engine crankshaft and the timing edge of the turning slide valve (7). The advantage of the regulating slide-valve gear according to the invention is the possibility of continuous regulation of the optimum conditions of port timing in respect of actual parameters of the running two-stroke engine. The advantage of the arrangement of the turning slide valve (7) with two coaxial carried and counterrotating disks consists in the velocity of closing or opening the engine port (C).

Description

Regulating slide-valve gear

The invention relates to a regulating slide-valve gear which is suitable especially for an asymmetrical timing of a two- stroke engine port.

Turning slide valves of various constructions and arrangements being used above all for timing of two-stroke engine suction are known well. Their main disadvantage is the invariable timing of the engine port. Such a construction is illustrated e.g. in the Czechoslovak author's certificate No. 215 744.

However, some solutions are known by now the aim of which was removing of the above mentioned disadvantage of the internal combustion engine regulation and optimizing of the positions of the gear elements according to actual operating conditions of the engine. These devices are mechanical, electromagnetic and hydraulic. The mechanical devices are often based on an epicyclic gear. A rather complicated device that serves for varying of the valve timing of an internal combustion engine in dependence on its loading and speed is described in DOS No. 31 46 613. In this device helical gears and pinions axially sliding on the splined parts of camshafts are used.

An other solution based on mechanical principle is described in DOS No. 37 37 602. In this case a differential gear with bevel gears is used. The same problem is concerned by UK patent No. 2 167 123. However, devices of similar type for two-stroke engines with slide-valve gear are not known, and a simple application of the above mentioned, structurally complicated devices is not usable under the specific conditions occuring at the two-stroke engines.

The above mentioned disadvantages are removed by means of the regulating slide-valve gear according to the invention in which a sensing and regulating unit senses the parameters of the engine in operation, primarily engine speed, evaluates the indicated parameters and by means of an electrical connection operates a control device. A regulating element of

SUBSTITUTE SHEET the control device is connected to the controlled element cf an epicyclic gear. A movement of the controlled element changes the mutual angular position of a driving element towards the driven element of the epicyclic gear. The driving element of the epicyclic gear is kiπenaticly connected on the one hand with the crankshaft of the engine and on the other hand via the controlled element with the driven element of the epicyclic gear. The epicyclic gear is connected by a gearing with at least one slide-valve shaft pivoted within a slide-valve housing. The trajectory of the turning slide valve cuts the engine port. The sensing and regulating unit controles the angular position of tne engine crankshaft and the timing edge of the turning slide valve to each other. The timing edge of the turning slide valve disk is defined by an edge of a cut-out crossing the port during the rotation of the slide-valve disk the full surface of which closes the port.

The advantage of the regulating slide-valve gear is the possibility of a continuous varying of the port timing with respect to the actual running characteristics of the two-stroke engine. An advantage of the alternative embodiment of the turning slide valve with two counterrotating and coaxial arranged disks is the speed of opening or closing of the engine port.

The basic scheme of the regulating slide-valve gear is shown in fig. 1. There is a side-view of a coπtrolable epicyclic gear in fig. 2. In fig. 3 an epicyclic gear with bevel gears is presented and its side-view is shown in fig. 4. There is an epicyclic gear v/ith double satellite in fig. 5 and its side- view is in fig. 6. Fig. 7 shows a turning slide valve with two disks and there is an epicyclic gear with bevel gears and an inclined axis of the satellite in fig. 0. Fig. 9 shows the turning slide valve and an engine port, and in fig. 10 the turning slide valve with its other parts is shown. Fig. 11 presents a turning slide valve within an exhaust port in front view and fig. 12 shows an example of an exhaust port timing schematicly. There is a side-view of a turning slide valve placed within the engine exhaust port in fig. 13. Fig. 14 presents a top view of a regulating slide-valve gear and fig. 15 shows the relative position of the slide-valve disks for the maximum time opening of the port when the piston is found in bottom dead center. A scheme of the maximum timing of the slide valve is shown in fig. 16, and fig. 17 shows a relative position of the slide valve disks for the minimal opening of the port. An example of the minimal timing is schematicly sketched in fig. 18, and fig. 19 shows an epicyclic gear with bevel gears.

According to fig. 1 to 6 the epicyclic gear 1 of the regulating slide-valve gear consists of at least three basic elements. The driving element of the epicyclic gear 1 is functionally connected with the engine crankshaft and at the same time by means of a controlled element 4 with the driven element of the epicyclic gear which is connected by a transmission 5 with at least one slide-valve shaft 6 of the turning slide valve 7. The turning slide valve 7 is pivoted within a slide-valve housing 8 which is inserted in the engine port C. The controlled element 4 of the epicyclic gear 1 is connected with a regulating element of the control device 3 the electrical input of which is connected with an output of a sensing and regulating unit 2. The sensing and regulating unit 2 senses the actual parameters of the running engine and regulates the mutual angular position of the engine crankshaft and the timing edge of the turning slide valve 7. Major axis of the epicyclic gear 1 and the axis of the turning slide valve 7 are skew lines, perpendicular lines, parallel lines, concurrent lines or they are identical. The axis of the turning slide valve 7 is towards the axis of the engine crankshaft skew, perpendicular, parallel, concurrent or identical. However, the axis of the turning slide valve 7 can be perpendicular to the plane given by the axis of the engine crankshaft and the axis of the cylinder. In addition, the axis of the turning slide valve 7 can be perpendicular to the axis of the respective engine cylinder.

SUBSTITUTE SHEET The driving sun gear 11 of the epicyclic gear 1 (Fir.. 0) with bevel gearing is in mesh with at least one satellite 12 bein in mesh ,.ith a driven sun gear 13. The axis of the at least one satellite 12 contains with the axis of the driving sun gear 11 an angle which is smaller than right angle. The satellite 12 is borne by an satellite-gear carrier 14 being connected with a regulating element of the control device 3. The driven sun gear 13 is in mesh with at least one driven bevel gear 15 the axis of which is perpendicular to the major axis of the epicyclic gear 1.

The transmission 5 (Fig. 1) connecting the epicyclic gear 1 with at least one turning slide valve 7 is realized like a gearing or a shape connection using a friction drive, a chain or an indented belt drive. For reaching of high rate of timing the turning slide valve 7 consists of two slide-valve disks 71, 72 (Fig. 7). The first slide-valve disk 71 is fixed on an internal slide-valve shaft 61 and the second slide-valve disk 72 is fixed on the hollow slide-valve shaft 62. These shafts are coaxial so that the internal slide-valve shaft 61 is pivoted within the hollow slide-valve shaft 62 being pivoted within a bearing part of the slide-valve housing 8. There is a space inside the slide-valve housing 8 in which the first slide-valve disk 71 and the adjacent second slide-valve disk 72 rotate. The sense of rotation of the second slide-valve disk 72 is inverse with regard to the sense of rotation of the first slide-valve disk 71. The whole slide-valve housing 8 is positioned within the engine body so that the trajectory of the pair of the counterrotating slide-valve disks 71 and 72 crosses the engine port C (Fig. 9). In the moment of the mutual overlap of the timing edges of the slide-valve disks 71, 72 the engine port C would not be closed perfectly as the room of the cut-outs of the disks of the turning slide valve 7 is not sealed till the timing edges overlap the port edges. A partition of the space given by the cut-out of the disk of the turning slide valve 7 is carried out by an application of at least one bar 73 which is arranged on a level with the disk of the turning slide valve 7 in such a way that it follows with the rotary form keeping the outside diameter of the disk, and the bar 73 makes a window. There is a window at the timing edge of the disk of the turning slide valve 7 the opening angle of which is at least a half of the timing angle of the engine port C. In addition, the disk of the turning slide valve 7 (Fig. 10) can be provided with a ring 74 and a support rib 75. On the ring 74 a balancing body 76 can be arranged.

The regulating slide-valve gear (Figs. 11 to 18) arranged in the exhaust port C of a two-stroke engine gives in combination with the engine piston timing an asymmetrical timing RC (Figs. 12, 16, 18) of the engine exhaust port C (Fig. 14). The control device 3 can be realized in great numbers of different forms. Electrical regulating pulses from the sensing and regulating unit 2 of an electromagnetic form of the control device 3 are transformated into separate regulating steps of the regulating element being connected with the satellite-gear carrier 14 of the epicyclic gear 1. All the figures showing the positions of the^{^}disks of the turning slide valves 7 (Figs. 11, 12, 15, 16, 17, 18) relate to the bottom dead center of the engine piston. For the control the result of which should be the overlap of the slide-valve disks 71, 72 at minimum engine speed and the corresponding asymmetrical timing RC (Fig. 18) the engine revolution speed is the main information to be sensed. At high engine revolution speed (Fig. 18) the opening of the exhaust port C corresponds to the maximum of the asymmetrical timing RC (Fig. 16). The epicyclic gear 1 with bevel gears (Fig. 14) has the axis of the satellite 12 inclined, and the axes of the input and output of the torque include right angle. The driving sun gear 11 is connected with the crankshaft by means of toothed wheels. The driven bevel gear 15 is connected with the driving pulley 51 by means of a connecting shaft 16.

In the form using a belt drive with a belt indented on both its sides the axis of the driving pulley 51 is skew towards the axis of slide-valve pulleys 53, 54 so that the indented belt 52 with double-sided teeth is led from the driving pulley 51 via

SUBSTITUTE SHEET - fi ¬

at least first slide-valve pulley 53 to a returning pulley 55. The axis of the returning pulley 55 is also skew towards the axis of the slide-valve pulleys 53, 54. From the returning pulley 55 the indented belt 52 is led back via at least one second slide-valve pulley 54 in such a way that the sense of rotation of each pair of the coaxial slide-valve pulleys 53, 54 is inverse. The port C of the two-stroke engine passes the slide-valve housing 8 (Fig. 13).

In the simple form of the epicyclic gear 1 (Fig. 19) with the bevel gears the driving sun gear 11 mates by means of the satellite 12 with the driven sun gear 13. The satellite 12 is borne by the satellite-gear carrier 14 which is connected to a regulating element of the control device 3.

Claims

C L A I M S

1. A regulating slide-valve gear especially for a two-stroke engine consisting of at least one turning slide valve and an epicyclic gear connected kiπematicly with the engine crankshaft and consisting of at least three basic elements one of which is connected to a control device , in which a driving element of the epicyclic gear (1) is kinematicly connected on the one hand with the engine crankshaft and on the other hand by means of a controlled element (4) with a driven element of the epicyclic gear (1) being connected by means of a transmission (5) with at least one slide-valve shaft (6) of a turning slide valve (7) pivoted within a slide-valve housing (3) arranged in the engine port ^'(C), the controlled element (4) of the epicyclic gear (1) is connected to a regulating element of the control device the electrical input of which is connected with an output of a sensing and regulating unit (2) of the actual parameters of the engine and of the mutual angular position of the engine crankshaft towards the timing edge of the turning slide valve (7).

2. A regulating slide-valve gear according to claim 1, in which the major axis of the epicyclic gear (1) is skew towards the axis of the turning slide valve (7).

3. A regulating slide-valve gear according to claim 1, in which the major axis of the epicyclic gear (1) is perpendicular towards the axis of the turning slide valve (7).

4. A regulating slide-valve gear according to claim 1, in which the major axis of the epicyclic gear (1) is parallel towards the axis of the turning slide valve (7).

5. A regulating slide-valve gear according to claim 1, in which the major axis of the epicyclic gear (1) is identical with the axis of the turning slide valve (7).

6. A regulating slide-valve gear according to claim 1, in which the axis of the turning slide valve (7) is skew towards the axis of the engine crankshaft.

7. A regulating slide-valve gear according to claim 1, in which the axis of the turning slide valve (7) is parallel to the axis of the engine crankshaft.

8. A regulating slide valve-gear according to claim 1, in which the epicyclic gear (1) is a bevel gearing the driving sun gear (11) of which is connected by means of at least one satellite (12) with a driven sun gear (13), the axis of the satellite (12) includes with the axis of the driving sun gear (11) an angle which is smaller than right angle, the satellite (12) is borne by a satellite-gear carrier (14) being connected with a regulating element of the control device (3), and the driven sun gear (13) is connected by means of a gearing with at least one driven bevel gear (15) the axis of which is perpendicular to the major axis of the epicyclic gear (1).

9. A regulating slide-valve gear according to claim 1, in which the turning slide valve (7) comprises two slide-valve disks (71, 72), the first slide-valve disk (71) is fixed on an internal slide-valve shaft (61), the second slide-valve disk (72) is fixed on a hollow slide-valve shaft (62), and these shafts are arranged coaxially so that the internal slide- valve shaft (61) is pivoted within the hollow slide-valve shaft (62) being pivoted within a bearing part of the slide-valve housing (8) involving a space for rotary motion of the first slide-valve disk (71) and the adjacent second slide-valve disk (72) the sense of rotation of which is inverse with regard to the sense of rotation of the first slide-valve disk (71), and the whole slide-valve housing (8) is arranged within the engine body in such a position that the trajectory of the pair of the counterrotating slide-valve disks (71 and 72) passes the engine port (C).

10. A regulating slide-valve gear according to claim 9, in which at least one disk of the turning slide valve (7) is provided with at least one bar (73) arranged on a level with the disk of the turning slide valve (7), the bar (73) consists of an edge ring part following the outside diameter of the disk and a straight part being positioned se that the bar (73) makes a window at the timing edge of the disk of the turning slide valve (7), and the opening angle of the window is at least a half of the timing angle of the engine port (C).

SUBSTITUTE SHEET