Rotary piston machine, especially rotary engine

Abstract

A rotary piston machine is disclosed. In one aspect, the machine includes a piston chamber that is defined in a housing by a first sidewall, a second sidewall and a peripheral wall interconnecting these sidewalls and a rotary piston that is rotatably arranged in the piston chamber and has a first face and a second face. The first face of the rotary piston faces an interior of the first sidewall of the piston chamber and the second face of the rotary piston faces an interior of the second sidewall of the piston chamber. at least one ventilation bore is provided in the first and/or the second sidewall of the piston chamber and connected to at least one ventilation channel, wherein the at least one ventilation bore is arranged at a location that radially lies within at least one first lateral seal.

Claims

1. A rotary piston machine, comprising: a housing; a piston chamber that is defined in the housing by a first sidewall, a second sidewall and a peripheral wall interconnecting the first and second sidewalls; a rotary piston that is rotatably arranged in the piston chamber and has a first face and a second face, wherein the first face of the rotary piston faces an interior of the first sidewall of the piston chamber and the second face of the rotary piston faces an interior of the second sidewall of the piston chamber; at least two working zones formed between a peripheral surface of the rotary piston and the peripheral wall of the piston chamber; at least one first lateral seal that is provided on the first and second faces of the rotary piston in order to seal intermediate spaces between the first and the second sidewall of the piston chamber and the first and second faces of the rotary piston relative to the working zones; a central bore; at least one second lateral seal that is provided on the first and the second face of the rotary piston in order to seal the respective intermediate spaces between the first and second sidewalls of the piston chamber and the first and second faces of the rotary piston relative to the central bore; at least one ventilation bore provided only in one of the first and second sidewalls of the piston chamber and connected to at least one ventilation channel in the housing for discharging gases from the housing, wherein the at least one ventilation bore is arranged at a location that radially lies within the at least one first lateral seal and outside the at least one second lateral seal; wherein the at least one second lateral seal is arranged radially within the at least one first lateral seal and wherein the at least one ventilation bore lies radially outside the at least one second lateral seal; wherein the at least one ventilation bore lies within an angular segment; and wherein no other bore is provided in the first or second sidewall.

2. The rotary piston machine according to claim 1 further comprising, on its peripheral surface, at least one radial seal that protrudes in the direction toward the peripheral wall of the piston chamber, and wherein the at least one ventilation bore lies radially within the at least one radial seal.

3. The rotary piston machine according to claim 1, wherein the at least one ventilation bore lies within an angular segment of the cold arc of the piston chamber.

4. The rotary piston machine according to claim 1 further comprising at least one cavity that extends from the first face to the second face radially within the at least one first lateral seal or between the at least one first lateral seal and the at least one second lateral seal.

5. The rotary piston machine according to claim 1 further comprising, in the region of each working zone: at least one first recess in the first face radially within the at least one first lateral seal or between the at least one first lateral seal and the at least one second lateral seal; and at least one second recess in the second face radially within the at least one first lateral seal or between the at least one first lateral seal and the at least one second lateral seal.

6. The rotary piston machine according to claim 1, wherein the at least one ventilation bore is connected to the ventilation channel via at least one connecting channel.

7. The rotary piston machine according to claim 1, wherein at least one of the ventilation bore and a connecting channel is at least partially realized in an ascending fashion in the direction toward the ventilation channel.

8. The rotary piston machine according to claim 1, further comprising at least one throttle or diaphragm configured to influence the respective opening cross section of the ventilation bore or a connecting channel provided in or on the at least one ventilation bore and/or the at least one connecting channel.

9. The rotary piston machine according to claim 1, wherein the ventilation bore has an elongated cross section in the concentric direction of the rotary piston.

10. The rotary piston machine according to claim 9, wherein the ventilation bore has an essentially reniform cross section.

11. The rotary piston machine according to claim 1, further comprising an additional connecting channel configured to connect the central bore of the rotary piston to the ventilation channel.

12. The rotary piston machine according to claim 11, wherein at least one of the ventilation channel, the connecting channel and the additional connecting channel comprises a labyrinth.

13. The rotary piston machine according to claim 11, wherein at least one of the ventilation channel, the connecting channel and the additional connecting channel comprises at least one plenum chamber.

14. The rotary piston machine according to claim 1, wherein the machine is suitable for use as a range extender for an electrically operated motor vehicle.

15. A power generating unit comprising a rotary piston machine, wherein the rotary machine comprises: a housing; a piston chamber that is defined in the housing by a first sidewall, a second sidewall and a peripheral wall interconnecting the first and second sidewalls; a rotary piston that is rotatably arranged in the piston chamber and has a first face and a second face, wherein the first face of the rotary piston faces an interior of the first sidewall of the piston chamber and the second face of the rotary piston faces an interior of the second sidewall of the piston chamber; at least two working zones formed between a peripheral surface of the rotary piston and the peripheral wall of the piston chamber; at least one first lateral seal that is provided on the first and second faces of the rotary piston in order to seal intermediate spaces between the first and the second sidewall of the piston chamber and the first and second faces of the rotary piston relative to the working zones; a central bore; at least one second lateral seal that is provided on the first and the second face of the rotary piston in order to seal the respective intermediate spaces between the first and second sidewalls of the piston chamber and the first and second faces of the rotary piston relative to the central bore; at least one ventilation bore provided only in one of the first and second sidewalls of the piston chamber and connected to at least one ventilation channel in the housing for discharging gases from the housing, wherein the at least one ventilation bore is arranged at a location that radially lies within the at least one first lateral seal and outside the at least one second lateral seal; wherein the at least one second lateral seal is arranged radially within the at least one first lateral seal and wherein the at least one ventilation bore lies radially outside the at least one second lateral seal; a rotatably supported shaft, on which the rotary piston revolves, provided in the housing and coupled to an electromechanical energy converter, wherein the at least one ventilation bore lies within an angular segment; and wherein no other bore is provided in the first or second sidewall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a longitudinal section through a detail of a rotary piston machine.

(2) FIG. 2 shows a cross section through a detail of the rotary piston machine in FIG. 1.

(3) FIG. 3 shows the longitudinal section of FIG. 1, with a ventilation bore equipped with a device configured to purposefully influence the cross section of a flow channel.

(4) FIG. 4 shows the longitudinal section of FIG. 1, with a connecting channel equipped with a device configured to purposefully influence the cross section of a flow channel.

DETAILED DESCRIPTION

(5) Embodiments will be described with reference to the accompanying drawings.

(6) One embodiment uses the example of a rotary engine with an essentially triangular rotary piston in this case. A piston chamber 12 is arranged in a housing 10 of the rotary piston machine, wherein said piston chamber is defined by a first sidewall 14 and a second sidewall 16 that are axially (right/left direction in FIG. 1) spaced apart from one another and essentially aligned parallel to one another, as well as a peripheral wall 18 that axially interconnects these sidewalls 14 and 16. The peripheral wall 18 of the piston chamber 12 has a trochoid-shaped inner running surface. In this exemplary embodiment, the walls 14, 16, 18 of the piston chamber 12 are realized in the form of components that are manufactured separately of the remaining machine housing 10.

(7) The driveshaft 20 is rotatably supported in the housing by means of bearing devices 22, 24. In a rotary engine, this driveshaft 20 has an eccentric section 26.

(8) This eccentric shaft 20 is coupled to a (not-shown) electromechanical energy converter in order to form a power generating unit. The electromechanical energy converter may consist, for example, of a generator that converts the mechanical energy of rotation of the eccentric shaft 20 into electrical energy during the operation of the rotary piston machine in order to subsequently store this electrical energy, for example, in a (not-shown) electrochemical energy storage device such as, for example, a battery, an accumulator or the like.

(9) The energy stored in the energy storage device can then be used for operating, for example, an electric motor that drives at least one wheel of a motor vehicle. In this case, the power generating unit with the rotary engine and the generator serves as a so-called Range Extender that, if so required, recharges the battery of the electrically operated motor vehicle and thusly extends the range of the motor vehicle.

(10) According to FIG. 1, a rotary piston 28 arranged in the piston chamber 12 is seated on the eccentric section 26 and revolves about the driveshaft 20, wherein a bearing device 33, for example, in the form of a needle bearing is provided between the eccentric section 26 of the driveshaft 20 and the rotary piston 28.

(11) In some embodiments, the rotary piston 28 is essentially realized with a triangular shape such that three working zones 34 are formed between its peripheral surface 31 and the peripheral wall 18 of the piston chamber 12. The four cycles of a rotary engine conventionally take place in these three working chambers 34 in order to turn the rotary piston.

(12) The rotary piston 28 has a first face 29 (on the left in FIG. 1) that faces an interior 15 of the first sidewall 14 of the piston chamber 12 and a second face 30 (on the right in FIG. 1) that faces an interior 17 of the second sidewall 16 of the piston chamber 12. The rotary piston 28 furthermore features a central bore 32, through which the driveshaft 20 extends. This central bore 32 of the rotary piston 28 is realized with an internal gear that is engaged with a gearwheel 35 arranged on the housing 10 in a rotationally rigid fashion coaxial to the eccentric shaft 20. The movement of the rotary piston 28 in the housing 10 is controlled with the gearwheel 35.

(13) The central bore 32 of the rotary piston 28 forms a volume that is connected to an oil circuit and supplied with lubricating oil by means of an oil pump during the operation of the rotary engine. This lubricating oil serves for lubricating the bearing points 22, 24, 26 of the eccentric shaft 20 in the housing 10 and of the rotary piston 28 on the eccentric shaft 20.

(14) Radial seals 58 are provided in the three corners of the rotary piston 28 in order to seal the three working zones 34 relative to one another. According to FIG. 2, these radial seals 58 are essentially realized in a strip-shaped fashion and fixed in correspondingly shaped grooves 57 in sealing bolts 56. The sealing bolts 56 respectively extend axially through the rotary piston 28 in a corner region thereof. In addition, they may be contacted by the adjacent first lateral seals 36, 37 on the first and the second face 29, 30 of the rotary piston 28.

(15) In addition, several seals 36-41 are provided in the respective intermediate spaces between the sidewalls 14, 16 of the piston chamber 12 and the faces 29, 30 of the rotary piston 28 in order to seal these intermediate spaces with respect to blow-by gases escaping from the working zones 34 on the one hand and with respect to the admission of lubricating oil from the central bore 32 of the rotary piston 28 on the other hand.

(16) In more precise terms, a first lateral seal 36 is arranged on the first face 29 of the rotary piston 28 in order to seal the intermediate space relative to the working zones 34 and a first lateral seal 37 is arranged on the second face 30 of the rotary piston 28 in order to seal the intermediate space relative to the working zones 34. Both of these first lateral seals 36, 37 may be elastically prestressed relative to the respective sidewall 14, 16 of the piston chamber 12.

(17) Furthermore, two radially spaced-apart second lateral seals 38, 40 are arranged on the first face 29 of the rotary piston 28 in order to seal the intermediate space relative to the central bore 32 and two radially spaced-apart second lateral seals 39, 41 are arranged on the second face 30 of the rotary piston 28 in order to seal the intermediate space relative to the central bore 32. These second lateral seals 38, 39, 40, 41 may be also elastically prestressed relative to the respective sidewall 14, 16 of the piston chamber 12. The second lateral seals 38, 40 and 39, 41 are arranged in pairs and also referred to as oil seals or scraper rings.

(18) According to FIG. 1, a first recess 42 is provided in the first face 29 of the rotary piston 28 radially between the first lateral seal 36 and the radially outermost second lateral seal 38. A second recess 44 is analogously provided in the second face 30 of the rotary piston 28 radially between the first lateral seal 37 and the radially outermost second lateral seal 39. These two recesses 42, 44 in the faces 29, 30 of the rotary piston 28 are also interconnected by means of a through-opening 43.

(19) Instead of the construction according to FIG. 1 that features two recesses 42, 44 in the two faces 29, 30 and a through-opening 43 extending between said recesses, the rotary piston 28 may also be realized with a continuous cavity that directly interconnects the two faces 29, 30 of the rotary piston 28 radially between the first and the second lateral seals 36, 37 and 38, 39.

(20) If blow-by gases escape from the working zones 34 of the piston chamber 12 into the intermediate spaces between the sidewalls 14, 16 of the piston chamber 12 and the faces 29, 30 of the rotary piston during the operation of the rotary piston machine despite the first lateral seals 36, 37, these blow-by gases can be accommodated in the recesses 42, 44. The pressure generated in the intermediate spaces due to the blow-by gases is reduced or lowered due to the volume of the recesses 42, 44. In addition, a pressure compensation between the first face 29 and the second face 30 of the rotary piston 28 is achieved due to the through-opening 43 extending between the two recesses 42, 44.

(21) FIG. 1 also shows a ventilation bore 46 in the first sidewall 14 of the piston chamber 12. This ventilation bore 46 is arranged at a location that radially lies between the first lateral seal 36 and the radially outer second lateral seal 38 at the time of ignition. In this way, blow-by gases that escape into the intermediate spaces through the first lateral seals 36, 37 on the rotary piston 28 due to the high pressure in the respective working zones 34 after the ignition can be discharged through the ventilation bore 46 in the first sidewall 14.

(22) In more precise terms, the ventilation bore 46 is positioned on the second face 30 of the rotary piston 28 radially within an inner envelope of the first lateral seal 37 (over one complete revolution of the rotary piston 28) and outside an outer envelope of the radially outer second lateral seal 39. In addition, the ventilation bore 46 is also positioned radially within an inner envelope of the groove bottoms 57 for the radial seals 58 in the sealing bolts 56.

(23) The described choice of the position of the ventilation bore 46 in the first sidewall 14 of the piston chamber 12 makes it possible to ensure that this ventilation bore 46 is connected to the section of the intermediate space between the face 29 of the rotary piston 28 and the sidewall 14, in which blow-by gases can accumulate, in all operating positions of the rotary piston 28 and that a direct fluidic connection with one of the working zones 34 is never produced.

(24) Although not illustrated in the figures, several cooling medium bores are arranged in the sidewalls 14 and 16 of the piston chamber in the region of the so-called hot arc in order to cool the rotary piston machine. This is the reason why the ventilation bore 46 may be positioned in the angular segment of the so-called cold arc of the piston chamber 12, in which no cooling medium bores are arranged in the sidewalls 14, 16.

(25) The ventilation bore 46 may have an essentially elongate cross section 46A as or reniform cross section 46B, as illustrated in FIG. 2, in the concentric direction in order to improve the efficiency of discharging the blow-by gases through the ventilation bore.

(26) A connecting channel 48 connects the ventilation bore 46 in the first sidewall 14 to a ventilation channel 50 in the housing 10, through which the blow-by gases can be discharged from the housing 10. In this case, the ventilation channel 50 is connected to an oil separating device 52 in order to achieve a largely complete separation of lubricating oils entrained by the blow-by gases. The separated oils are fed to an oilpan (not shown) that is connected to the lubricating oil circuit of the rotary piston machine via a (not-shown) drainage channel. Since the separated lubricating oil is returned into the oil pan, this lubricating oil is once again available to the lubricating oil circuit. Consequently, the quantity of lubricating oil required for the operation of the rotary piston machine can be minimized.

(27) According to FIG. 1, the connecting channel 48 between the ventilation bore 46 in the first sidewall 14 of the piston chamber 12 and the ventilation channel 50 in the housing 10 is realized in an ascending fashion in the flow direction of the blow-by gases. The ventilation bore 46 itself may be alternatively or additionally provided with such an ascent. The ventilation bore 46 may furthermore be equipped with a throttle or diaphragm, (device 80 shown in FIG. 3) in order to purposefully influence the cross section of the flow channel. The connecting channel 48 may furthermore be equipped with a throttle or diaphragm, (device 85 shown in FIG. 4) in order to purposefully influence the cross section of the flow channel. Due to the above-described measures, lubricating oils or the like entrained by the blow-by gases already can be more or less separated at these locations.

(28) Furthermore, the central bore 32 of the rotary piston 28 is also connected to the ventilation channel 50 in the housing 10 by means of an additional connecting channel 54. In this way, the usually relatively small quantities of blow-by gases that escape into the central bore 32 of the rotary piston 28 through the second lateral seals 38-41 between the faces 29, 30 of the rotary piston 28 and the sidewalls 14, 16 of the piston chamber 12 can also be discharged. This additional connecting channel 54 is also realized in an ascending fashion in the flow direction of the blow-by gases. This makes it possible to increase the separation rate of the lubricating oil from the blow-by gases originating from the central bore 32.

(29) Although not illustrated in the figures, the ventilation channel 50, the connecting channel 48 and/or the additional connecting channel 54 feature labyrinth-like sections and/or at least one plenum chamber 95. These measures already improve the oil separation from the blow-by gases in the housing 10 and respectively make it possible to achieve a more compact design of the rotary piston machine and to provide a smaller oil separating device 52 on the downstream end of the ventilation channel 50.

(30) The compact design of the embodiment of the rotary engine illustrated in FIG. 1 contains only one common ventilation channel 50 on the side of the first sidewall 14 of the piston chamber 12 in the housing 10. However, it is basically also possible to provide ventilation channels 50 to both sides of the piston chamber 12 such that the blow-by gases can be discharged on both faces 29, 30 of the rotary piston 28.

(31) The cross-sectional shapes and sizes of the connecting channels 48, 54 leading to the ventilation channel 50 make it possible to adjust pressure differences between the recesses 42, 44, the central bore 32 and the ventilation channel 50 in the desired fashion.

(32) At least one of the disclosed embodiments provides a rotary piston machine with improved ventilation of blow-by gases that escape from the working zones in the piston chamber into the intermediate spaces between the sidewalls of the piston chamber and the faces of the rotary piston.

(33) While the above embodiment have been described with reference to the accompanying drawings, they are for illustrative purposes only and do not limit the invention. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the invention.