FR2884556A1 - Vehicle IC engine energy recuperator has Rankine cycle system with single loop containing compressor and evaporators connected to exhaust pipe - Google Patents

Abstract

An energy recuperator uses a Rankine thermodynamic cycle system coupled to an engine exhaust pipe (2) with at least one pollution extractor such as a catalytic converter, particle filter or nitrogen oxide (NOx) trap. The Rankine system comprises a single fluid loop (4) containing a compressor, and evaporators (5, 7) coupled thermally to the exhaust gases, an expander/recuperator (6) and condensers (8). The evaporators are situated before and/or after the pollution extractor, and the system can also incorporate a thermal exchange regulator between the evaporators and exhaust gases.

Description

the loop comprises evaporator means located upstream of at least one

pollution control body,

  the device comprises means for regulating the heat exchange between the evaporator means and the exhaust gases; the loop comprises evaporator means located downstream of a depollution device; the loop comprises first and second components; evaporator means located downstream of a depollution device, the loop comprises first and second evaporator means located upstream of a depollution device, the first and second evaporator means are integrated in a single heat exchanger, the exhaust line comprises means for selectively diverting at least a portion of the exhaust gas, able to regulate the amount of exhaust gas in heat exchange with the Rankine cycle fluid loop, The exhaust comprises at least one depollution device comprised among the following components: catalyst, particulate filter, Nox trap, the exhaust line comprises pumping means. re-catalysis arranged upstream of the one or more of the depollution devices and, on the other hand, the evaporator means, the device comprises catalytic means integrated in evaporator means, the evaporator means comprise a suitable heat exchanger. thermally coupling the fluid of the loop and the exhaust gas, the catalytic means being disposed on surfaces of the evaporator means able on the one hand to be in contact with the flow of the exhaust gas and on the other hand, to be coupled thermally directly or indirectly with the fluid of the loop.

  the device comprises NOx trap means integrated into the evaporator means.

  The invention also relates to a motor vehicle comprising an internal combustion engine, an exhaust line comprising at least one pollution control device, and an energy recovery device according to any one of the preceding characteristics.

  Other features and advantages will appear on reading the description below, with reference to the figures in which: FIG 1 shows a schematic view of a first embodiment of the energy recovery device of an internal combustion engine according to the invention, - Figures 2, 3, 3a, 4, 5, 6 and 7 respectively show schematic and simplified views of seven other embodiments of the device according to the invention, - Figure 8 is a diagrammatic sectional view of a detail of FIGS. 5 to 7, illustrating the structure of an evaporator exchanger providing a catalytic function of the device according to the invention; FIGS. 9 to 13 schematically illustrate five architectures respectively; of hybrid-powered vehicles using the energy recovered via a Rankine cycle.

  The invention will now be described with reference to the embodiment of FIG. 1. An exhaust line 2 comprising a depollution member 3 is connected to the thermal engine 1. The depollution member 3 is, for example, a catalyst and / or a particle filter and / or a Nox trap or any other equivalent means or a combination of these means.

  A loop 4 of Rankine thermodynamic cycle fluid is thermally coupled to the exhaust line 2. The fluid of the loop 4 is for example water. In what follows, thermal transfer or heat exchange is any transfer of calories or frigories between two elements, either directly or indirectly via a vector such as a fluid.

  The loop 4 comprises a pump 13 for compressing the water. The water heats up and then vaporizes in a preheater 5 during a heat exchange with the exhaust gas. The preheater 5 consists, for example, of a first heat exchanger water / exhaust gas. The water is also heated and vaporized in a second exchanger 7 water / exhaust gas also called recuperator or superheater 7. In these two heat exchangers 5, 7, the exhaust gases give calories to water. The steam obtained then undergoes expansion in a turbine 6 thus providing a recoverable work on a rotating shaft 16. This energy can be used directly to mechanically drive an organ, or be converted into electricity in an electric converter 26.

  The water vapor is then returned to its initial liquid state in a condenser 8 which cools it. The condenser 8 may consist of a heat exchanger capable of thermally coupling the water of the loop 4 with air or any other cooling fluid. The thermal power to be dissipated in the condenser 8 may if necessary be used to heat a passenger compartment or an organ for example.

  The device according to the invention has a great compactness, a high efficiency while having a relatively simple structure.

  The preheater 5 and the recuperator 7 are respectively disposed downstream and upstream of the depollution member 3, the upstream and downstream qualifiers referring to the direction of flow of the exhaust gases.

  Advantageously, regulation means 9 can be provided to control the heat exchange between on the one hand the preheater 5 and recuperator 7 and on the other hand the exhaust gas.

  For example, the exhaust line 2 comprises two separate ducts and a valve 9 for distributing the flow of exhaust gas between the two ducts 2. Preferably, the two ducts 2 pass through the body 3 depollution. One of the two ducts 2 is in heat exchange with the preheater 5 and recuperator exchangers 7, while the other duct 2 is not in heat exchange with the latter. Thus, the control of the valve 9 makes it possible to determine the quantity of exhaust gas thermally coupled to the Rankine loop 4.

  The regulation means 9, 2 thus make it possible to control the temperature of the exhaust gases entering the pollution control member 3 without greatly affecting the thermodynamic efficiency of the Rankine loop 4.

  Furthermore, in the case where the 3 depollution member comprises a catalyst, the control means 9, 2 can not compromise the priming of the catalyst when its temperature is relatively low. This architecture also makes it possible to install a superheater 7 as close as possible to the exhaust manifold of the engine 1. This makes it possible to provide superheater / exhaust heat exchange at a location where the gas temperatures are very high. which gives a high return to the Rankine cycle.

  In addition, the regulation means 9, 2 make it possible to divert all or part of the exhaust gases when the engine 1 is operating at full load and the thermal power of the exhaust gases is too great compared to the dimensioning of the rest of the system .

  The position of the superheater 7 upstream of the depollution member 3 is particularly advantageous when the latter comprises a Nox trap 3. Indeed, in this case, the superheater 7 can ensure selective cooling of the exhaust gas before entering the Nox trap 3 when they have a temperature is too important. In this way, the invention makes it possible to guarantee compliance with the operating temperature and efficiency window of the NOx trap 3, in particular when the engine 1 is of the direct injection gasoline type.

  This architecture has the additional advantage of not requiring a specific calibration of the engine control to maintain the temperature of the exhaust gas below a threshold temperature (800 C for example). Indeed, for a gasoline engine it can be common to reach temperatures above this threshold, especially on high load operating points. Such a calibration according to the prior art is penalizing in terms of efficiency and consumption (overconsumption) of the engine.

  Figures 2, 3, 3bis, 4, 5, 6, 7 and 8 illustrate other embodiments of the invention. For the sake of simplicity and brevity, in these figures, elements identical to those described above are designated by the same reference numerals and are not described in detail a second time. In addition, the Rankine cycle loop 4 is shown partially and schematically. That is, only the heat exchangers thermally coupled to the exhaust gas (evaporator 5 and / or heater 7) are shown.

  The embodiment of FIG. 2 differs from that of FIG. 1 only in that the exhaust line 2 does not comprise means of regulating the heat exchange between on the one hand the preheater 5 and the recuperator 7 and on the other hand, the exhaust gases. That is, the exhaust line 2 has a single duct which is thermally coupled with the evaporator 5 and the superheater 7.

  The embodiment of FIG. 3 differs from that of FIG. 2 only in that it does not include a heat exchanger forming a recuperator / superheater upstream of the depollution member 3. That is, the Rankine cycle 4 loop has only a heat exchanger 5, 7 forming an evaporator thermally coupled to the exhaust line 2, downstream of the depollution member 3. Advantageously, a precatalysis member (not shown) may be disposed upstream of the depollution member 3.

  This single evaporator 5, 7 may optionally perform the function of the superheater described above. This can be achieved by choosing an appropriate dimensioning of the evaporator 5, 7 (i.e., its exchange surface).

  The effectiveness of this dual evaporator 5 / superheater function 7 within a single exchanger will also depend on the thermal conditions of the exhaust gas (temperature and power) and the control strategy of the loop (temperature and fluid flow rate). within the loop).

  This architecture is particularly suitable when the depollution member 3 comprises a catalyst. Indeed, the evaporator 5, 7 is not likely to disturb the rise in temperature of the catalyst during cold starts of the vehicle.

  The embodiment of FIG. 3bis differs from that of FIG. 2 in that on the one hand a precatalysis member 11 is disposed upstream of the depollution member 3 and, on the other hand, means 30, 31 bypass of the exhaust gas are provided downstream of the body 3 of pollution control. The means 30, 31 for diverting the exhaust gases located downstream of the pollution control member 3 are arranged to enable the quantity of exhaust gas to be heat exchanged with the evaporator 5, 7 to be controlled. For example, downstream of the depollution member 3, the exhaust line 2 comprises a portion with two branches 30, only one of which is thermally coupled with the evaporator / superheater 5, 7. Distribution means such that a valve 31 makes it possible to determine the distribution of exhaust gas in the two branches 31. This embodiment has the additional advantage of making it possible to regulate the flow of gas entering the evaporator 5, 7 and therefore the level of power exchanged. This function is particularly advantageous when the engine 1 operates at high loads.

  The embodiment of FIG. 4 differs from that of FIG. 2 only in that the superheater 7 is thermally coupled to the exhaust line 2 downstream of the depollution member 3. More precisely, the superheater 7 is located between the depollution member 3 and the evaporator 5.

  The implementation of the superheater 7 downstream of the organ 3 depollution member has the advantage of not cooling the exhaust gas before entering the body 3 depollution. This is particularly advantageous when the depollution member 3 comprises a catalyst which requires for its initiation relatively high minimum temperature.

  In the embodiment of Figure 5, the loop 4 comprises a single heat exchanger 5, 7 providing the functions of evaporator 5 and superheater 7. The heat exchanger 5, 7 is disposed downstream of an organ 11 optional precatalysis and upstream of a depollution module comprising a particle filter 33 and a Nox trap 3. Furthermore, the Rankine cycle loop 4 comprises means 12 for regulating the flow of fluid intended to come into thermal exchange with the exhaust gases in the exchanger 5, 7.

  For example, a controlled valve 12 makes it possible to control the flow of water flowing in the evaporator / superheater 5, 7.

  Furthermore, and preferably, the exchanger 5, 7 evaporator / superheater also provides a catalytic function 133 for the treatment of exhaust gas. For example, and as shown in Figure 8, conventional catalyst means 133 are disposed on one of the surfaces of the exchanger 5, 7 adapted to be in contact with the flow of exhaust gas. For example, catalytic compounds 133 are deposited on fin surfaces 34 of the exchanger 5, 7. The fins 34 are thermally coupled io directly or indirectly with the fluid of the loop 4 which circulates in the exchanger 5, 7. For example, the fluid of the Rankine loop circulates in passages 35 contiguous to the fins 34.

  This architecture, which has a high efficiency in terms of heat exchange and catalysis, has a particularly small footprint.

  The embodiment of FIG. 6 differs from that of FIGS. 5 and 8 only in that the functions of evaporation and superheating are provided by two separate heat exchangers 5, 7 disposed respectively downstream and upstream of the module. 3, 33 depollution. The superheater 7 is in turn placed downstream means 11 of precatalysis. As previously, a controlled valve 12 can be provided to control the flow of water of the loop 4 which circulates in the evaporator 5 and / or the superheater 7. As previously, the exchanger constituting the superheater 7 can also integrate in its within the means 133 of catalysis.

  The embodiment of FIG. 7 differs from that of FIGS. 5 and 8 only in that the depollution module 3 comprises only a particle filter 33, the means 3 forming a Nox trap also being integrated in the exchanger 5, 7 evaporator / superheater. Indeed, in the same way as for the means 133 for catalysis, the Nox trap means 3 can be integrated within the exchanger 5, 7.

  Figures 9 to 13 respectively illustrate five examples of hybrid propulsion vehicle architectures able to use the energy recovered via a Rankine cycle. For the sake of brevity, the identical elements are designated by the same reference numerals and are not described in detail several times. These architectures are preferably intended to be associated with energy recovery devices such as those described above, however, these architectures can be associated with any other type of energy recovery device.

  The architecture shown schematically in Figure 9 comprises a heat engine 1, the output shaft 101 is adapted to be coupled to a gearbox 15 via friction means 14 such as a clutch. The output shaft 115 of the gearbox is coupled to wheels 18 (only one wheel is represented symbolically).

  Furthermore, an alternator 17 has an output shaft 117 adapted to be coupled to the heat engine 1 via friction means 14. As shown, a compressor 19 of an air-conditioning system can be coupled to the heat engine 1 via a belt system 119. The belt 119 of the compressor 19 can be connected at the level of the shaft of the heat engine 1 intended to be coupled to the alternator 17.

  The output shaft of a turbine 26 or any other energy recovery device can be coupled, via a friction 14 and a belt 219, to the output shaft 117 of the alternator 17. The turbine 26 can in particular belong to a loop 4 Rankine cycle, such as those described above.

  The architecture of FIG. 10 differs from that of FIG. 9 only in that the output shaft of the air conditioning compressor 19 is coupled directly to the belt 219 connecting the turbine 26 to the alternator 17.

  The architecture of FIG. 11 differs from that of FIGS. 9 and 10 in that: a first electrical machine 20 is interposed between the gearbox 15 and the thermal engine 1, respective friction means 14 enabling selective coupling of the latter with the electric machine 20, - the output shaft of the turbine 26 is connected to a second electrical machine 120, - the second electrical machine 120 is electrically connected (cables 22) to a battery 23 and the first machine electrical 20.

  In this way, the energy generated by the turbine 26 can be converted into electricity in the second electrical machine 120 for supplying batteries 23 and / or the first electrical machine 20 when necessary (and vice versa).

  In the architecture of Figure 12, the heat engine 1 and a first electric motor 24 transmit the torque to the wheels 18 via a transmission system 25 of the type, for example, gear. The output shaft of a second electric motor 27 is also connected to the transmission mechanism 25. The output shaft of the turbine 26 is connected to an electric machine which is able to feed batteries 23 and a 27 to less electric motors, (the feeds and exchanges are symbolized by arrows 50).

  The architecture of FIG. 13 differs from that of FIG. 12 only in that it does not comprise an electric machine, the output shaft of the turbine 26 being able to be coupled to the output shaft of the first 24 electric motor via a friction 14 and a belt system 219.

Claims (14)

  1. Device for recovering energy from an internal combustion engine by means of a Rankine thermodynamic cycle system coupled to the exhaust line (2) of the engine (1), the exhaust line (2) comprising at least one depollution member (3, 33, 11), characterized in that the Rankine cycle system comprises a single fluid loop (4) comprising compression means (13), means (5) , 7) evaporators capable of being thermally coupled with the exhaust gas, means (6) of relaxation / energy recovery and means (8) condensers.   2. Device according to claim 1, characterized in that the loop (4) comprises means (5, 7) evaporators located upstream of at least one member (3, 33, 133) depollution.   3. Device according to claim 2, characterized in that it comprises means (12) for regulating the heat exchange between the means (5, 7) evaporators and the exhaust gas.   4. Device according to any one of the preceding claims, characterized in that the loop (4) comprises means (5, 7) evaporators located downstream of a body (3, 33, 133) depollution.   5. Device according to claim 1, characterized in that the loop (4) comprises first (5) and second (7) means (5) evaporators located downstream of a body (3, 33, 133) depollution.   6. Device according to any one of claims 1 to 3, characterized in that the loop (4) comprises first (5) and second (7) means (5) evaporators located upstream of a member (3) of pollution.   7. Device according to claim 5 or 6, characterized in that the first (5) and second (7) evaporator means are integrated in a single heat exchanger.   8. Device according to any one of the preceding claims, characterized in that the line (2) exhaust comprises means (9, 30, 31) selective bypass of at least a portion of the exhaust gas, suitable regulating the amount of exhaust gas in heat exchange with the loop (4) of Rankine cycle fluid.   9. Device according to any one of the preceding claims, characterized in that the exhaust line (2) comprises at least one member (3, 33, 133) depollution included among the following organs: catalyst, particulate filter, Nox trap.   10. Device according to any one of the preceding claims, characterized in that the exhaust line (2) comprises means (11) of pre-catalysis arranged upstream on the one hand of or bodies (3, 33) of depollution and, secondly, means (5, 7) evaporators.   11. Device according to any one of the preceding claims, characterized in that it comprises means (133) of catalysis integrated in means (5, 7) evaporators.   12. Device according to claim 11, characterized in that the means (5, 7) evaporators comprise a heat exchanger capable of thermally coupling the fluid of the loop (4) and the exhaust gas, and in that the means (133) ) of catalysis are arranged on surfaces evaporator means (5, 7) able on the one hand to be in contact with the flow of the exhaust gas and secondly, to be thermally coupled directly or indirectly with the fluid of the loop (4).   13. Device according to any one of the preceding claims, characterized in that it comprises means (3, 33) of Nox trap integrated in the means (5, 7) evaporators.   14. Motor vehicle comprising an internal combustion engine and an exhaust line (2) comprising at least one depollution element (3, 33, 11), characterized in that it comprises a device for recovering energy in accordance with any one of the preceding claims.