FR3057608A1 - VARIABLE VOLUME TURBINE AND THERMOMECHANICAL ENERGY CONVERSION SYSTEM INCORPORATING IT - Google Patents

Abstract

The turbine according to the invention comprises a fixed volute (7F) and a moving volute (7M) having spiral walls interleaved one inside the other, the mobile scroll being able to perform a rotary orbital movement relative to a central axis ( AA) of the fixed volute, and a fluid chamber (7V) formed by a volume available between the spiral walls of the fixed and mobile scrolls. According to the invention, the turbine comprises a mechanically actuated volume variator (72) able to modify a useful volume of the fluid chamber by an axial displacement (d) of a chamber volume reduction soleplate (720) which is housed between the spiral walls of the fixed and mobile scrolls.

Description

Holder (s): PEUGEOT CITROEN AUTOMOBILES SA Société anonyme.

Extension request (s)

Agent (s): PEUGEOT CITROEN AUTOMOBILES SA Public limited company.

VARIABLE VOLUME TURBINE AND THERMOMECHANICAL ENERGY CONVERSION SYSTEM INCORPORATING THE SAME.

FR 3 057 608 - A1 tüy) The turbine according to the invention comprises a fixed volute (7F) and a mobile volute (7M) having spiral walls nested one inside the other, the mobile volute being able to perform a movement rotary orbital relative to a central axis (AA) of the fixed scroll, and a fluid chamber (7V) formed by an available volume between the spiral walls of the fixed and movable scrolls. According to the invention, the turbine comprises a mechanically actuated volume variator (72) capable of modifying a useful volume of the fluid chamber by an axial movement (d) of a chamber volume reduction soleplate (720) which is housed between the spiral walls of the fixed and mobile scrolls.

TURBINE WITH VARIABLE VOLUME AND THERMOMECHANICAL ENERGY CONVERSION SYSTEM INCORPORATING THE SAME [001] The invention relates to a spiro-orbital turbine, called scroll scroll turbine, with variable volume. The invention also relates to a thermomechanical energy conversion system equipped with such a scroll turbine operating in expander mode, in particular for the recovery of thermal energy from the exhaust gases of a heat engine of a means of transport. of any kind, such as land, rail, sea and air.

In a means of transport with an internal combustion engine, a large part of the fuel energy is lost in the form of dissipated heat. Thus, in a heat engine, the fuel energy lost in the form of heat is around 53%. The waste heat from a heat engine can partially be recovered and converted into hydraulic, mechanical or electrical energy through the use of the Rankine thermodynamic cycle.

Referring to Fig.1, there is known a thermomechanical energy conversion system 1 for recovering the heat from the exhaust gases EG of a heat engine to convert it into mechanical energy ME by means of a scroll expander 2. The EG exhaust gases are used as a heat source to transform a working fluid WA, such as water or a refrigerant, into vapor in an evaporator 3. The working fluid WA, placed under pressure by means of a working fluid pump 4, passes through the evaporator 3 to be converted into high pressure steam HPV while being heated by the exhaust gases EG. The HPV pressurized steam is led into the scroll expander 2 and expands providing a job. This work is recovered in the form of mechanical energy ME by the rotation of a shaft 20 mechanically coupled to a movable volute (not shown) of the expander 2. The expanded steam leaving the scroll expander 2 can be partially recirculated in the expander by a recirculation device 5 formed by a steam working fluid separator 50 and a pump 51. This recirculation is not essential for the functioning of the system, but it can bring an improvement in the yield by completing the expansion steam which provides additional work. The expanded steam completes its condensation in the form of working fluid, such as water, in a condenser 6 equipped with a cooling means 60. An outlet of the condenser 6 supplies working fluid to the pump 4 for the continuation of the cycle. energy conversion. The ME mechanical energy available can be used directly, or converted into electrical energy using a rotating electrical machine.

When such a thermomechanical energy conversion system with scroll expander is installed in a motor vehicle, it is necessary that the useful volume of the scroll expander can be modified and adjusted to the life situation of the vehicle. Indeed, depending on the life situation of the vehicle, the thermal energy contained in the exhaust gases varies. The scroll expander must therefore be able to work on different optimal operating points in order to obtain a good energy recovery efficiency, and avoid a known phenomenon of under-expansion or over-expansion liable to degrade the efficiency of the system.

From document FR2991403 of the prior art, a scroll turbine with variable volume is known. In this turbine, there is provided a hydraulic actuation mechanism which controls a movement of the movable volute relative to a fixed volute, and thus authorizes an adjustment of the useful volume of the turbine.

The present invention aims to provide a variable volume scroll turbine of a new type, thus offering designers an alternative to the use of prior art variable volume scroll turbines.

According to a first aspect, the invention relates to a scroll type turbine with variable volume comprising a fixed volute and a movable volute having spiral walls nested one inside the other, the movable volute being able to accomplish a movement rotary orbital relative to a central axis of the fixed scroll, and a fluid chamber formed by an available volume between the spiral walls of the fixed and movable scrolls. According to the invention, the turbine comprises a volume variator with mechanical actuation capable of modifying a useful volume of the fluid chamber by an axial displacement of a chamber volume reduction soleplate which is housed between the spiral walls of the volutes fixed and mobile.

According to another particular characteristic of the invention, the variator comprises at least one rod mounted to slide in a corresponding bore of a fixed casing of the turbine and having a first end mechanically fixed to the sole and a second end, distant of the sole, which is mechanically coupled to actuation means in translation.

According to yet another particular characteristic of the invention, the means of actuation in translation comprise a plate movable in translation and a worm screw mounted in a threaded through orifice of the movable plate, the second end, distant from the sole , being mechanically coupled to the movable plate which is actuated in translation by the rotation of the worm.

According to yet another particular characteristic of the invention, the rotation of the worm is controlled by means of a bidirectional rotary actuator.

According to yet another particular characteristic of the invention, the bidirectional rotary actuator is an electric motor.

According to a particular embodiment of the invention, the variator comprises four said sliding mounted rods having first ends mechanically fixed to the sole and second ends, distant from the sole, mechanically coupled to the actuation means in translation .

According to another aspect, the invention relates to a thermomechanical energy conversion system able to be installed in a means of transport emitting hot exhaust gases, the system comprising a working fluid circuit operating according to the cycle thermodynamics of Rankine, the circuit comprising a first working fluid pump, an evaporator receiving working fluid under pressure supplied by the first working fluid pump and heated in the evaporator by the exhaust gases for transformation under the forms a high pressure steam, a scroll type turbine, operating as an expander, receiving the high pressure steam supplied by the evaporator and converting steam work into mechanical energy available on a rotating shaft of the turbine, and a condenser receiving expanded steam supplied by the turbine and delivering the working fluid (WA) supplied to the first working fluid pump. According to the invention, the turbine is a scroll type turbine according to the invention as briefly described above.

According to another particular characteristic, the system comprises a vapor recirculation device associated with the turbine and comprising a fluid separator for working steam and a second pump.

The invention also relates to a motor vehicle equipped with the thermomechanical energy conversion system described briefly above.

Other advantages and characteristics of the present invention will appear more clearly on reading the description below of several particular embodiments of the scroll turbine according to the invention, in which:

- Fig. 1 is a block diagram showing the architecture of a thermomechanical energy conversion system for recovering thermal energy from the exhaust gases of a means of transport;

- Fig.2A is a simplified sectional view of a variable volume scroll turbine according to the invention, in a state of full power capacity;

- Fig.2B is a simplified sectional view of a variable volume scroll turbine according to the invention, in a state of reduced power capacity; and

- Fig.3 is a perspective view showing a volume variator with mechanical actuation included in the variable volume scroll turbine of Figs.2A and 2B.

Referring to Figs.2A, 2B and 3, there is now described a particular embodiment of a scroll turbine 7 according to the invention. It will be noted that the turbine 7 is shown here voluntarily in a partial and simplified manner, essentially showing the functional components of the turbine in relation to the invention, so as to facilitate understanding of the latter.

As shown in Figs.2A and 2B, the turbine 7 comprises a fixed scroll 7F and a movable scroll 7M, scroll casings 70F and 70M, a fluid inlet / outlet nozzle 71 and a volume variator to mechanical actuation 72. The mechanically actuated volume variator 72 will be detailed below in the description, also with reference to FIG. 3.

Conventionally, the fixed scroll 7F and the movable scroll 7M are spirals nested one inside the other which define a fluid chamber 7V formed by an available volume between the spiral walls of the fixed scrolls 7F and mobile 7M . The fluid chamber 7V is a volume expansion or volumetric compression chamber depending on whether the turbine 7 operates as an expander or as a compressor.

The sectional views of Figs.2A and 2B reveal the sections of the spiral walls of the scrolls 7F and 7M.

The spiral wall of the scroll 7F rests on an inner face of the scroll casing 70F with which it forms a single piece in this embodiment. The volute casing 70F has orifices 700F for its mechanical fixing by screws to a support.

The spiral wall of the volute 7M rests on an inner face of the volute casing 70M. The volute casing 70M is designed to allow an orbital rotary movement of the mobile volute 7M around a central axis AA of the fixed volute 7F, in its state nested with the fixed volute 7F.

The tops of the walls of the scrolls 7F and 7M are provided with sealing elements 71F and 71 M, respectively. These sealing elements 71F and 71M are in contact with the corresponding inner faces of the casings 70M and 70F, respectively, so as to form the chamber 7V in a hermetic manner, with only two fluid inlets / outlets, one for the fluid. at high pressure and the other for low pressure fluid. Only one of these fluid inlets / outlets, namely the nozzle 71, is apparent in FIGS. 2A and 2B. In an energy conversion system 1 as shown in FIG. 1, the turbine 7 integrated in such a system operates as an expander and the nozzle 71 then constitutes the inlet for the high pressure steam HPV.

Referring also to Fig.3, there is now described in detail the volume variator with mechanical actuation 72.

In this particular embodiment, the volume variator 72 essentially comprises a chamber volume reduction sole 720, a plate movable in translation 721, four sliding rods for mechanical connection 721a to 721 d, an endless screw 722 and a bidirectional rotary actuator 723.

The sole 720 has a substantially circular shape and has a spiral cutout 720a allowing insertion into the latter of the wall of the fixed scroll 7F, and solid parts 720b which are provided to adjust in spaces of the chamber 7V between the walls of the fixed scroll 7F and mobile 7M, as shown in Figs. 2A and 2B.

The sole 720 and the plate 721, which is also here of circular shape, are mechanically linked by the four rods 721a to 721 d. The sole 720 and the plate 721 are located in parallel planes, perpendicular to the central axis AA. The four rods

721a to 721 d are parallel to the central axis AA and are fixed at their ends at the circumferential zones of the sole 720 and the plate 721. These circumferential zones are here arranged in a rectangle.

The plate 721 is pierced in its center, along the central axis AA, to form a threaded through orifice in which the worm screw 722 is mounted. The worm screw 722 is mechanically coupled, at its end distant from the sole 720, to the rotary actuator 723 which is provided for attachment to a support. The rotary actuator 723 is here typically an electric motor which can be actuated in both directions of rotation, clockwise and counterclockwise.

As shown in Figs.2A and 2B, the rods 721a to 721 d are slidably mounted in corresponding bores of the fixed casing 70F, parallel to the axis AA. Only the bores 701F, 702F, for the sliding rods for mechanical connection 721a, 721b, are visible in Figs. 2A and 2B.

According to the invention, the variation of the useful volume of the chamber 7V of the scroll turbine 7 is obtained by the axial displacement (distance d in FIG. 2B) of the sole 720, along the axis AA. This displacement is obtained by means of the rotation of the endless screw 722 which causes a translation along the axis AA of the assembly formed by the plate 721, the sliding rods for mechanical connection 721a to 721 d and the sole 720. The direction of translation of the sole 720 is determined by the direction of rotation of the worm 722 set in motion by the rotary actuator 723. As shown in FIGS. 2A and 2B, the rotary actuator 723 is interfaced with a connection of COM communication, for example of the LIN or CAN type, authorizing the control thereof by an electronic control unit of the vehicle and therefore the control of the useful volume of the chamber 7V.

It will be noted that the sliding rods for mechanical connection are not necessarily four in number, being here simply an example of embodiment. In low power applications, a single sliding rod, of larger diameter, arranged near the central zone (axis AA) could prove to be sufficient for correct functioning of the sole.

In Fig.2A, the sole 720 is shown in a withdrawal position, pressed into abutment against the inner face of the housing 70F. In this position, the useful volume of the chamber 7V is at its maximum and the turbine 7 is then configured for full power capacity.

In Fig, 2B, the sole 720 has been moved axially by the distance d relative to the inner face of the fixed casing 70F and consequently reduces the useful volume of the chamber 7V. The turbine 7 is then configured for a reduced power capacity. By adjusting the distance d, it is thus possible to adjust the volume of the scroll turbine 7 to obtain optimal operating points. The scroll turbine 7 according to the invention, in expander mode, allows good energy recovery efficiency in the thermomechanical energy conversion system of FIG. 1.

Of course, the invention is not limited to the particular embodiments of the scroll turbine according to the invention described here by way of example. A person skilled in the art, depending on the applications of the invention, can make various modifications and variants which fall within the scope of the appended claims.

Claims (10)

1. Variable volume turbine comprising a fixed volute (7F) and a mobile volute (7M) having spiral walls nested one inside the other, the mobile volute (7M) being able to perform an orbital rotary movement relative to a central axis (AA) of said fixed scroll (7F), and a fluid chamber (7V) formed by an available volume between said spiral walls of said fixed (7F) and mobile (7M) scrolls, characterized in that it comprises a mechanically actuated volume variator (72) capable of modifying a useful volume of said fluid chamber (7V) by an axial displacement (d) of a chamber volume reduction soleplate (720) which is housed between said spiroidal walls said fixed (7F) and mobile (7M) scrolls. 2. Turbine according to claim 1, characterized in that said variator (72) comprises at least one rod (721a to 721 d) slidingly mounted in a corresponding bore (701 F, 702F) of a fixed casing (70F) of said turbine and having a first end mechanically fixed to said sole (720) and a second end, distant from said sole (720), which is mechanically coupled to actuation means in translation (721,722, 723). 3. Turbine according to claim 2, characterized in that said means for actuating in translation comprise a plate movable in translation (721) and a worm (722) mounted in a threaded through orifice of said movable plate (721), said second end, distant from said sole (720), being mechanically coupled to said movable plate (721) which is actuated in translation by the rotation of said worm (722). 4. Turbine according to claim 3, characterized in that the rotation of the worm (722) is controlled by means of a bidirectional rotary actuator (723). 5. Turbine according to claim 4, characterized in that said bidirectional rotary actuator is an electric motor (723). 6. Turbine according to any one of claims 2 to 5, characterized in that said variator comprises four said rods (721a to 721 d) sliding mounted having first ends mechanically fixed to said sole (721) and second ends, distant of said sole (721), mechanically coupled to said means for actuating in translation (721,722, 723). 7. Thermomechanical energy conversion system capable of being installed in a means of transport emitting hot exhaust gases, said system comprising a working fluid circuit operating according to the thermodynamic Rankine cycle, said circuit comprising a first pump working fluid (4), an evaporator (3) receiving pressurized working fluid (WA) supplied by said first pump (4) and heated in said evaporator (3) by said exhaust gases (EG) for transformation in the form of high pressure steam (HPV), a turbine operating as an expander, receiving said high pressure steam (HPV) supplied by said evaporator (3) and converting a work of said steam (HPV) into mechanical energy (ME) available on a rotary shaft (20) of said turbine, and a condenser (20) receiving expanded steam supplied by said turbine and delivering said working fluid (WA) supplied as input to lad ite first working fluid pump (4), characterized in that said turbine is a turbine (7) according to any one of claims 1 to 6. 8. System according to claim 7, characterized in that said working fluid is water. 9. System according to claim 7 or 8, characterized in that comprises a vapor recirculation device (5) associated with said turbine and comprising a working fluid-vapor separator (50) and a second pump (51). 10. A means of transport such as a motor vehicle, characterized in that it comprises a thermomechanical energy conversion system according to any one of claims 7 to 9. 1/2 720 2/2