JP4985665B2 - Waste heat regeneration system - Google Patents

Description

  The present invention relates to an exhaust heat regeneration system that regenerates exhaust heat of cooling water or exhaust gas in an engine of an automobile or the like as power by a Rankine cycle.

  As a fluid pump with an expander that is used in the Rankine cycle, a fluid pump that pumps the liquid refrigerant in the Rankine cycle and an expander that outputs mechanical energy by the expansion of the superheated steam refrigerant are integrally formed. The heat of the working fluid flowing through the expander outlet side passage after finishing the work is transferred to the working fluid flowing through the pump outlet side passage, thereby increasing the amount of superheat of the working fluid on the inflow side of the expander. There is one that can increase the expansion work in (see, for example, Patent Document 1).

  Further, in a complex fluid machine in which a compressor, an expander, a drive motor, and a circulation pump are integrally provided, the pump is disconnected from the rotating electrical machine by the intermittent switching means, and the pump becomes an operating resistance of the rotating electrical machine. In addition, the expansion of the working fluid can be sufficiently obtained, but when the operation of the compressor is unnecessary, it becomes possible to generate electricity by operating the rotating electricity as a generator with the driving force of the expander. There is one that can regenerate energy as electric energy (see, for example, Patent Document 2).

  Furthermore, a Rankine cycle in which a working fluid (also referred to as a refrigerant) circulates is provided, and a pump that boosts the working fluid, an expander that expands the working fluid, a pump as a motor, and a power generator that drives the expander as a generator. It is an integrated unit configured by connecting a load machine that generates electricity using it, and is a block that suppresses heat transfer between the expander and the pump (or the inlet side and outlet side of the pump) Some have walls (see, for example, Patent Document 3).

JP 2006-266238 A (Claim 1, pages 4-5) JP 2006-125340 A (Claim 1, page 4) JP 2007-138797 A (Claim 1, pages 2-3)

  In the exhaust heat regeneration system described in Patent Document 1, a part of the expander outlet side passage serving as the working fluid outlet side of the expander is disposed in the vicinity of a part of the pump outlet side passage serving as the working fluid outlet side of the pump. As a result, the amount of overheating of the working fluid on the inflow side of the expander is increased and the expansion work in the expander is increased, but heat is easily transferred to the pump side, and the pump temperature rises. The liquid refrigerant (hereinafter simply referred to as the refrigerant) evaporates at the pump inlet, and it is difficult to pressurize and circulate the refrigerant, which makes the Rankine cycle inoperable.

  Further, in the exhaust heat regeneration system described in Patent Document 2, when the compressor is driven by the rotating electrical machine, there is provided an intermittent switching means that can switch the connection state between the rotating electrical machine and the pump to the disconnected state. The pump can be driven by the driving force when the expander is activated, and a dedicated drive source for operating the pump is not required. However, as compared with Patent Document 1, the flow rate of the refrigerant is controlled. Although it is circulated to the pump and the cooling effect by the refrigerant is obtained, since it operates in parallel with the Rankine cycle, the temperature rise of the pump cannot be efficiently suppressed. For this reason, the refrigerant evaporates at the pump inlet, and it is difficult to pressurize and circulate the refrigerant, which makes the Rankine cycle inoperable.

  During the operation of the exhaust heat regeneration system, the cooling effect by the refrigerant can be obtained. However, when the refrigerant circulation amount decreases, the cooling effect by the refrigerant disappears especially when the operation is stopped. However, there is also a problem that the Rankine cycle cannot be operated again for several hours or more until the temperature of the entire pump-integrated expander decreases.

  Further, in the exhaust heat regeneration system described in Patent Document 3, a barrier wall is provided between the expander and the pump, and the working fluid expanded by the expander and the operation inside the pump via the barrier wall. In the integrated unit, the working fluid pressurized by the pump and the working fluid expanded by the expander perform heat exchange, so there is no need to provide a separate heat exchanger and a compact structure However, it is difficult to evaporate and evaporate the refrigerant at the pump entrance and circulate the refrigerant by boosting the temperature because the temperature rise of the pump cannot be efficiently suppressed as in the above patent document. Therefore, there was a problem that the Rankine cycle became inoperable.

  The present invention has been made to solve the above-described problems, and can prevent the temperature of the pump of the pump-integrated expander from rising. When the pump temperature rises, the invention quickly (for example, several The purpose is to obtain an exhaust heat regeneration system that can be cooled (in minutes) and that can always be operated stably, including restart.

  An exhaust heat regeneration system according to the present invention includes an evaporator that cools engine coolant by heat exchange with a refrigerant, an expander that expands the refrigerant heated via the evaporator and generates a driving force, An exhaust heat regeneration system comprising: a condenser that cools and condenses the refrigerant that passes through the expander; and a pump that pumps the refrigerant that is cooled through the condenser, and the refrigerant sent from the pump is the condenser Can only be distributed.

  According to the present invention, in the exhaust heat regeneration system in which the casing of the pump and the expander is integrated, at least a part of the refrigerant discharged from the pump is sent to the condenser, cooled and circulated to the pump. Therefore, the Rankine system that can prevent the pump temperature rise of the pump-integrated expander can be quickly cooled when the pump temperature rises and can operate stably including restart. It is to provide.

It is a block diagram which shows an example of the exhaust heat regeneration system in Embodiment 1 of this invention. It is a block diagram which shows another example of the exhaust heat regeneration system in Embodiment 1 of this invention. It is a block diagram which shows another example at the time of using the temperature sensor etc. of the waste heat regeneration system in Embodiment 1 of this invention. It is a block diagram which shows another example at the time of using the flow sensor etc. of the waste heat regeneration system in Embodiment 1 of this invention. It is a flowchart which shows the system control flow of the waste heat regeneration system in Embodiment 1 of this invention. It is a block diagram which shows the expander and pump in the waste heat regeneration system in Embodiment 1 of this invention. It is a block diagram which shows the waste heat regeneration system in Embodiment 2 of this invention. It is a front view which shows the outline of the flow path in the pump in Embodiment 2 of this invention. It is a side view which shows the outline of the flow path in the pump in Embodiment 2 of this invention. It is a Mollier diagram at the time of using R134a as a refrigerant.

Embodiment 1 FIG.
1 is a configuration diagram showing an exhaust heat regeneration system in Embodiment 1 of the present invention. The engine 1 is an internal combustion engine that generates driving force for driving an automobile. The engine cooling water heated by the engine 1 passes through the return cooling water circuit 2a, is cooled by the evaporator 3, and is again used for cooling the engine 1 through the going cooling water circuit 2b.

  The Rankine cycle 4 includes an evaporator 3 for cooling the engine coolant with the refrigerant, an expander 5 for expanding the refrigerant that has become high-temperature and high-pressure steam, a condenser 6 for cooling and condensing the expanded refrigerant, The pump 8 connected by the expander 5 and the output shaft 7, the three-way valve 9 for switching the refrigerant flow path, the first pipe 21 connecting the evaporator 3 and the expander 5, the expander 5 and the condenser 6 The second pipe 22 and the third pipe 23 for connecting the three, the fourth pipe 24 for connecting the condenser 6 and the pump 8, and the pump 8, the three-way valve 9, the three-way valve 9 and the evaporator 3, respectively. Although comprised from the 5th piping 25 and the 6th piping 26, although the three-way valve 9 is a component for operating Rankine cycle 4 like each piping, it is not directly related to Rankine cycle 4. The expander 5 and the pump 8 are integrated by a housing 10 and are connected to a motor generator 41 via a shaft 7.

  Next, the operation of the Rankine cycle 4 at the normal time will be described. For example, the Rankine cycle 4 is filled with a refrigerant such as R134a. The engine cooling water heated to about 90 ° C. to 100 ° C. by the engine 1 returns to the return cooling water circuit 2a and is cooled by the evaporator 3. In this process, the refrigerant is heated to become high-temperature and high-pressure steam at about 90 ° C. The refrigerant that has become high-temperature and high-pressure vapor passes through the first pipe 21, is sent to the expander 5, and generates power in the process of expanding in the expander 5. The power obtained here is used for driving a car or generating power.

  The refrigerant, which has become steam at about 60 ° C. after expansion, passes through the second pipe 22 and the third pipe 23 and is sent to the condenser 6 having a cooling function by running air, a fan or the like when the automobile is running, and is cooled by the condenser 6. Then, it is condensed and becomes a liquid of about 30 ° C., and is sent to the pump 8 through the fourth pipe 24.

  The liquid refrigerant is pressurized by the pump 8 and sent to the evaporator 3 through the fifth pipe 25 and the sixth pipe 26 connected via the three-way valve 9. The refrigerant sent to the evaporator 3 cools the engine cooling water heated to about 90 ° C. to 100 ° C. by the engine 1 and becomes high-temperature and high-pressure steam of about 90 ° C. The engine cooling water goes to the cooling water. The refrigerant is used again for cooling the engine 1 through the circuit 2b, and the refrigerant repeats the above process to continue the Rankine cycle 4.

  In the process of Rankine cycle 4, a part of the power generated by the expander 5 is used to drive the pump 8 connected by the output shaft 7, and the remaining power is taken out by the output shaft 7. As a result, it is used for assisting engine driving, generating electricity, etc., leading to improvements in energy efficiency, such as improving the fuel efficiency of automobiles.

  Next, the operation when the temperature of the pump 8 rises and the refrigerant evaporates at the inlet of the pump 8 and it becomes difficult to pressurize and circulate the refrigerant, and the Rankine cycle 4 becomes inoperable will be described. In Embodiment 1 of the present invention, a three-way valve 9 is provided between a fifth pipe 25 and a sixth pipe 26 that connect the pump 8 and the evaporator 3. The three-way valve 9 is provided in a form having a switching function such that it can flow to either the pump 8 and the evaporator 3 or the condenser 6, and the refrigerant discharged from the pump 8 is supplied to the evaporator 3 or the condenser 6. It is set as the structure which flows to either one of these.

  According to such a configuration, when the refrigerant discharged from the pump 8 by the three-way valve 9 is switched so as to be able to flow to the evaporator 3, that is, in the normal operation state, the exhaust from the engine 1 is performed. By operating Rankine cycle 4 with heat and generating motive power, it is used for assisting engine driving, generating electricity, etc., leading to improvements in energy efficiency, such as improving fuel efficiency of automobiles.

  Instead, when the output of the engine 1 decreases, the exhaust heat of the engine cooling water decreases. As a result, the circulation amount of the refrigerant also decreases and the heat exchange amount in the evaporator 3 also decreases. Rankine cycle 4 is operated in response to a decrease in the amount of heat exchange, but when such a phenomenon progresses, the temperature of pump 8 rises due to a reduction in the cooling effect of the circulating refrigerant, and the refrigerant is introduced at the inlet of pump 8. It evaporates and the refrigerant cannot be circulated and boosted, and the Rankine cycle 4 becomes inoperable.

  In such a case, the three-way valve 9 is switched so that the fifth pipe 25 connected to the pump 8 and the seventh pipe 27 and the third pipe 23 connected to the condenser 6 are circulated and discharged from the pump 8. By sending all the refrigerant to the condenser 6, the refrigerant is efficiently cooled by the condenser 6 without going through the process of being heated by the evaporator 3 and returned to the pump 8. Since no refrigerant is sent, high temperature refrigerant does not circulate in the expander 5. Therefore, there is no temperature rise of the pump 8 due to the influence of the heating of the expander 5, and the pump 8 is cooled very efficiently. In this case, since the power by Rankine cycle 4 cannot be obtained, pump 8 is driven by motor generator 41 or the like connected to output shaft 7.

  Thus, when the temperature of the pump 8 rises and the refrigerant evaporates at the inlet of the pump 8 and it becomes difficult to pressurize and circulate the refrigerant, and the Rankine cycle 4 becomes inoperable. By switching and operating the pump 8 efficiently, the pump 8 can be operated in a short time, the Rankine cycle 4 can be operated stably for a long time, and the fuel efficiency of the vehicle is improved. Leading to further energy efficiency improvements.

  Further, for example, it is assumed that the engine 1 is stopped, the Rankine cycle 4 is also stopped correspondingly, and the temperature of the pump 8 is increased. In such a case, the three-way valve 9 is switched and the pump 8 is switched. By allowing the refrigerant discharged from the refrigerant to flow through the condenser 6, the efficiently cooled refrigerant circulates through the pump 8, so that the vicinity of the pump 8 is quickly cooled (usually about several minutes), and thereafter When the engine 1 is restarted, the Rankine cycle 4 is stopped from the start of the engine 1 by switching so that the refrigerant discharged from the pump 8 by the three-way valve 9 can flow to the evaporator 3. The situation is avoided and the Rankine cycle 4 can be operated efficiently.

  Here, the switching control of the three-way valve 9 is provided with a sensor that measures the pressure or temperature of the refrigerant at the inlet of the pump 8, the temperature at or near the casing of the pump 8, the flow rate of the refrigerant, the operating frequency of the pump, or the like. This can be easily implemented by correlating the relationship between the stoppage of the Rankine cycle 4 and these relationships. FIG. 3 shows the first embodiment of the present invention in which a pressure sensor 52 for measuring the pressure of the fourth pipe 24 connected to the same position as the temperature sensor 51 for measuring the temperature of the refrigerant in the vicinity of the inlet of the pump 8 is installed. It is a lineblock diagram showing an exhaust heat regeneration system. In FIG. 3, the temperature sensor 51 may be a thermistor or a thermocouple, and the pressure sensor 52 may be a resistance strain gauge pressure sensor, for example.

Figure 5 shows a flow diagram of a system operation using the measured values of the pressure P and temperature T _P of the refrigerant entrance near the pump 8 by the temperature sensor 51 and pressure sensor 52. Hereinafter, a specific example of system control will be described with reference to FIG.

First, the temperature TP and pressure _P of the refrigerant in the vicinity of the inlet of the pump 8 are measured by the temperature sensor 51 and the pressure sensor 52. The saturated steam temperature _TL at the pressure P of the refrigerant used is calculated. If T _L -T _P is a temperature difference △ T _SET over a preset value, the three-way valve 9 with the fifth pipe 25 and the sixth pipe 26 is switched can flow, it initiates a start operation of the engine 1 The Rankine cycle 4 is operated and power is generated by the expander 5.

On the other hand, the temperature T _P of the refrigerant inlet vicinity rise of the pump 8, if T _L -T _P is a temperature difference △ T _SET smaller value set in advance, the fifth connected three-way valve 9 and the pump 8 It switches so that the 7th piping 27 and the 3rd piping 23 connected with the piping 25 and the condenser 6 may be distribute | circulated, and it will be in the state by which all the refrigerant | coolants discharged from the pump 8 are sent to the condenser 6. In this case, the refrigerant is efficiently cooled by the condenser 6 without going through the process of being heated by the evaporator 3 and returned to the pump 8, and the refrigerant is not sent to the evaporator 3. The refrigerant never circulates.

Therefore, there is no temperature rise of the pump 8 due to the influence of the heating of the expander 5, and the pump 8 is cooled very efficiently. In this case, since the power by Rankine cycle 4 cannot be obtained, pump 8 is driven by motor generator 41 or the like connected to output shaft 7. Thereafter, the temperature sensor 51 and repeatedly at a predetermined interval to measure the temperature T _P and the pressure P of the refrigerant entrance near the pump 8 by the pressure sensor 52, T _L -T temperature difference _P is preset △ T _SET more values Then, the engine 1 is started and operated.

Further, the engine 1 and the Rankine cycle 4 is in operation work, repeated measurement of the temperature T _P and the pressure P of the refrigerant entrance near the pump 8 by the temperature sensor 51 and pressure sensor 52 at predetermined intervals, T _L -T _P Is smaller than the preset temperature difference ΔT _SET , the fifth pipe 25 connected to the pump 8 through the three-way valve 9 and the seventh pipe 27 and the third pipe 23 connected to the condenser 6 are circulated. By switching so that all the refrigerant discharged from the pump 8 is sent to the condenser 6. In this case, the refrigerant is efficiently cooled by the condenser 6 without going through the process of being heated by the evaporator 3 and returned to the pump 8, and the refrigerant is not sent to the evaporator 3. The refrigerant never circulates.

Therefore, there is no temperature rise of the pump 8 due to the influence of the heating of the expander 5, and the pump 8 is cooled very efficiently. Becomes the temperature difference △ T _SET more values T _L -T _P is preset again, the three-way valve 9 is switched to allow communication with the fifth pipe 25 is a sixth pipe 26, the engine 1 and the Rankine cycle 4 normal again Continue driving. Here, ΔT _SET is theoretically 0 ° C. or higher, and a lower Rankine cycle efficiency can obtain higher Rankine cycle efficiency, but is usually set to about 5 ° C. for stable operation.

  In addition, it is possible to suppress the time for the engine cooling water to rise in a short time by setting the switching in a short time and shortening the time during which the refrigerant is not sent to the evaporator 3. There is little burden. In addition, although it is assumed that a slight fluctuation occurs in the temperature of the engine cooling water by performing such system control, the engine 1 is particularly affected by performing the control within a safe temperature. Needless to say, it doesn't happen.

  In the above description, the switching control example of the three-way valve 9 based on the pressure and temperature of the refrigerant has been shown. However, as shown in FIG. 4, the flow rate of the refrigerant and the operating frequency of the pump 8 are measured by the flow rate sensor 53 and the frequency sensor 54, respectively. However, it is also possible to perform switching control based on these values. In FIG. 4, the flow sensor 53 is installed at an arbitrary position of the fifth pipe 25, and measures the flow rate of the refrigerant flowing through the fifth pipe 25. The frequency sensor 54 detects the number of rotations per unit time of the output shaft 7 connected to the pump 8.

In general, a positive displacement pump such as a vane pump, a trochoid pump, or a gear pump is used as the pump 8, so that the refrigerant flow rate can be uniquely calculated from the operating frequency. An error (Q ₀ −Q) / Q ₀ between the flow rate Q measured by the flow rate sensor 53 and the flow rate Q ₀ calculated from the frequency measured by the frequency sensor 54 is larger than a preset flow rate error ΔQ _SET. when a value, determines that the pump 8 became hot, and smaller than the temperature difference △ T _sET to T _L -T _P is preset in the switching control of the three-way valve 9 based on the pressure and temperature of the refrigerant It becomes possible to perform the same operation as in the flow shown in FIG. Other system control methods are the same as the system control method based on the pressure and temperature of the refrigerant described above, and thus the description thereof is omitted. Here, ΔQ _SET is normally set to a value larger than about 0.05.

FIG. 9 shows a Mollier diagram when R134a is used as the refrigerant. In FIG. 9, when the pressure and temperature are known, it is possible to determine the three states of the refrigerant at that time, that is, the state of the liquid state, the gaseous state, or the mixed state of the liquid and the gas. At a pressure and a method of system control based on temperature of the refrigerant shown in FIG. 5, for example, the pressure P in the case of using R134a the refrigerant, a saturated vapor temperature T at a temperature T _P and the pressure P of the refrigerant entrance near the pump 8 _If FIG. 9 is used for the relationship of _L , it can be easily judged that it is a relationship as shown in a figure corresponding to a specific refrigerant | coolant (here R134a).

  In a general system control method, if it is determined that the refrigerant is in a gaseous state or a state where the liquid and the gas are mixed, it can be determined that the pump 8 is at a high temperature. Further, even if the state of the refrigerant is a liquid state, the likelihood until the pump 8 is determined to be high temperature, that is, the likelihood until the temperature at which the refrigerant evaporates in the pump 8 is different from the measured value. It becomes possible by evaluating. Therefore, when the temperature reaches a preset temperature, the Rankine cycle 4 can always be stably operated by cooling the pump 8 in advance.

  Further, as described above, the pump 8 can calculate and evaluate the flow rate uniquely based on the operation frequency based on the characteristics. When the Rankine cycle 4 is normally operated, the flow rate calculated from the operating frequency and the measured value of the refrigerant flow rate circulating through the Rankine cycle 4 substantially coincide with each other. In this case, it is determined that the pump 8 has reached a high temperature, the pump 8 can be cooled, and the Rankine cycle 4 can be stably operated.

  Even if it is difficult to directly measure the values of the refrigerant near the inlet of the pump 8 as described above, the so-called artisan can use the correlation between the radiator temperature and the fluid temperature. If so, it is easy to know. Further, the position where the sensor is provided is a design problem, and needless to say, it varies depending on the engine structure and the like.

  In the invention according to Embodiment 1 of the present invention, the refrigerant is caused to flow through the condenser by switching the three-way valve, and the refrigerant is circulated through the pump and the condenser, so that the pump is directly cooled. Therefore, a remarkable cooling effect of the pump can be exhibited. As a result, the pump can usually be cooled in a short time of less than 1 minute. Therefore, even if it is controlled based on the measurement values of these sensors, it can be instantly handled, and seizure of pistons, etc. Will not cause engine damage.

  In addition, it is not necessary to perform switching control of the three-way valve 9 using the above-described sensor, and the same effect can be obtained by using a temperature switch using bimetal that can be switched at a preset temperature.

  In comparison with the conventional example, for example, in the invention according to Patent Document 2, in order to cool the pump when the pump temperature rises, the refrigerant circuit is switched to reverse the expander integrated with the pump. Rotating, operating the refrigeration cycle and circulating a low-temperature refrigerant to the expander cools the entire casing and indirectly cools the pump. It takes a long time for cooling.

  For this reason, it is difficult to provide a three-way valve at the position shown in Embodiment 1 of the present invention, and if it is provided, the refrigerant flow path is switched so that the refrigerant does not flow to the evaporator, and the exhaust heat from the engine for a long time. Can not be dissipated by the evaporator, causing engine damage due to seizure of the piston or the like.

  In the invention according to Embodiment 1 of the present invention, the refrigerant is caused to flow through the condenser by switching the three-way valve, and the refrigerant is circulated through the pump and the condenser so that the pump is directly cooled. Because of this configuration, it is possible to exert a remarkable pump cooling effect, so that the pump can be cooled in a short time, usually within 1 minute, and engine switching due to seizure of pistons does not occur and switching is short. It can be controlled by time, and the Rankine cycle can be operated stably.

  As apparent from the above, the invention according to the conventional example and the invention according to the first embodiment of the present invention are different inventions having different technical ideas, and the effects produced by the invention are also significantly different.

  Also, instead of the three-way valve 9, by providing a flow rate adjusting valve that adjusts the flow rate of both the sixth pipe 26 and the seventh pipe 27 at the same position, the refrigerant flowing through each pipe is appropriately adjusted according to the situation. By doing so, the same effect can be obtained.

  FIG. 1 shows a configuration in which the pump 8 is driven by the motor generator 41 connected to the output shaft 7 when the power by the Rankine cycle 4 cannot be obtained and the pump 8 does not operate, as shown in FIG. In addition, a first pulley 42 provided on the output shaft 7 instead of the motor generator 41 and a second pulley 44 provided on the engine output shaft 43 of the engine 1 are connected via a belt 45 so as to be coupled to each other. The pump 8 may be driven by 1.

  Further, FIG. 1 shows a case where the expander 5 and the pump 8 are directly connected by the output shaft 7 and the expander 5 and the pump 8 are operated at the same time (Note that the three-way valve 9 is switched and discharged from the pump 8. If the refrigerant is allowed to flow through the condenser 6, no refrigerant flows through the Rankine cycle 4, so that no refrigerant flows through the expander 5 even if the expander 5 is operating. As shown in FIG. 2, the expander 5 and the pump 8 may be connected via a coupler 12. In this case, since the expander 5 is disconnected and only the pump 8 can be operated, it is possible to circulate the refrigerant between the pump 8 and the condenser 6 with less power, thereby further improving energy efficiency. Connected.

Embodiment 2. FIG.
FIG. 7 is a configuration diagram showing an exhaust heat regeneration system in Embodiment 2 of the present invention. Since the configuration and operation of the Rankine cycle 4 are the same as those in the first embodiment, description thereof is omitted.

  In FIG. 7, the pump 8 is relatively near the lowermost portion with respect to the condenser 6, where the vicinity of the lowermost portion specifically refers to the lower one third to the lower of the entire height direction of the condenser 6. The eighth pipe 28 for communicating the condenser 6 and the pump 8 is connected to the lower side of the pump 8 in the housing 10 containing the pump 8, and is connected via the flow rate adjustment valve 13. It is connected to the ninth pipe 29. The ninth pipe 29 is configured to be connected to the upper part of the condenser 6, where the upper part specifically refers to the upper one third to the upper part of the whole height direction of the condenser 6 and the second pipe 22. is doing. A tenth pipe 30 for pumping the refrigerant is provided between the pump 8 and the evaporator 3.

  FIG. 8a is a front view showing an outline of a flow path in the pump according to the second embodiment of the present invention. FIG. 8b is a side view schematically showing the flow path in the pump according to the second embodiment of the present invention. 8a and 8b show a trochoid pump as an example of the pump 8 according to Embodiment 2 of the present invention. 8a and 8b, the fourth flow path 24a inside the casing 10 connected to the fourth pipe 24 is provided with a branched eighth flow path 28a connected to the eighth pipe 28. 10 is configured such that the refrigerant can flow in one direction from below to above.

  In the exhaust heat regeneration system according to the second embodiment having such a configuration, while the Rankine cycle 4 is operating, the flow rate adjustment valve 13 is closed, and the expander is operated by the Rankine cycle 4 driven by the exhaust heat from the engine 1. By generating power at 5, the fuel efficiency of the vehicle is improved.

  On the other hand, when Rankine cycle 4 stops, flow control valve 13 is opened. When the temperature of the pump 8 becomes high, the refrigerant inside the casing 10 near the pump 8 evaporates, and the refrigerant evaporated in the fourth flow path 24a located inside the casing 10 has a difference in density between the liquid and the gas. The eighth flow path 28 a provided by branching from the four flow paths 24 a circulates and is sent to the eighth pipe 28. Therefore, the refrigerant flows into the condenser 6 to be cooled and liquefied, and then returns to the pump 8 and circulates naturally. In the exhaust heat regeneration system according to Embodiment 2 of the present invention, the vicinity of the pump 8 and the pump 8 can be efficiently cooled without having an external power source. Therefore, when the Rankine cycle 4 is restarted, the pump 8 can be operated, and the exhaust heat regeneration system can be operated stably.

  Further, in the second embodiment of the present invention, the method of efficiently cooling the vicinity of the pump 8 and the pump 8 without having an external power source has been described. However, the eighth pipe 28 or the ninth pipe 29 is described. The second pump 14 is newly provided at an arbitrary position and operated in conjunction with the flow rate adjustment valve 13, so that a stable cooling effect can be obtained regardless of whether the Rankine cycle 4 is operated or stopped.

  In addition, when such a structure is taken, even when the flow regulating valve 13 is removed, by controlling the operation state of the second pump 14, for example, when the second pump 14 is stopped, the second pump 14 itself Becomes a resistance, the refrigerant hardly flows, and when the second pump 14 is operated at the maximum capacity, the refrigerant can flow to the maximum, and the flow rate of the refrigerant can be controlled by controlling the capacity of the second pump 14. . For this reason, the effect similar to the exhaust-heat regeneration system in Embodiment 2 of the said description is acquired.

  1 engine, 2a return cooling water circuit, 2b bound cooling water circuit, 3 evaporator, 4 Rankine cycle, 5 expander, 6 condenser, 7 output shaft, 8 pump, 9 three-way valve, 10 housing, 12 coupler, 13 Flow control valve, 14 Second pump, 21 First pipe, 22 Second pipe, 23 Third pipe, 24 Fourth pipe, 24a Fourth flow path, 25 Fifth pipe, 26 Sixth pipe, 27 Seventh pipe , 28 8th piping, 28a 8th flow path, 29 9th piping, 30 10th piping, 41 Motor generator, 42 1st pulley, 43 Engine output shaft, 44 2nd pulley, 45 Belt, 51 Temperature sensor, 52 Pressure Sensor, 53 Flow sensor, 54 Frequency sensor

Claims (4)

An evaporator that cools the engine coolant by heat exchange with the refrigerant, an expander that expands the refrigerant that is heated via the evaporator to generate driving force, and a refrigerant that passes through the expander is cooled and condensed And a pump that pumps the cooled refrigerant through the condenser, and in the exhaust heat regeneration system in which the pump and the expander are integrated in a housing, the refrigerant sent from the pump is An exhaust heat regenerative system characterized in that it can be distributed only to a condenser.   A switching controllable three-way valve is provided for the refrigerant sent from the pump to flow to either the evaporator or the condenser, and the refrigerant can flow only to the condenser by switching the three-way valve. The exhaust heat regeneration system according to claim 1.   The exhaust heat regeneration system according to claim 2, wherein the switching control is performed by a thermal switch using a bimetal.   The switching control may be performed by any one of the pressure and temperature of the refrigerant at the inlet of the pump, the temperature of the pump housing, the temperature near the pump housing, the flow rate of the refrigerant circulating in the pump, or the operating frequency of the pump. The exhaust heat regeneration system according to claim 2, wherein the exhaust heat regeneration system is made based on one or more measured values.

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