JP2017145692A - Waste heat recovery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste heat recovery device using a Rankine cycle for recovering waste heat from an internal combustion engine while efficiently collecting refrigerant condensed inside a pipe connecting an expander and a condenser.SOLUTION: The waste heat recovery device includes a boiler for vaporizing refrigerant, a gas-liquid separator for separating the refrigerant delivered from the boiler into gas phase fluid and liquid phase fluid, a superheater for superheating the gas phase fluid delivered from the gas-liquid separator, the expander for expanding the gas phase fluid passing through the superheater to recover thermal energy, the condenser for condensing the gas phase fluid passing through the expander to restore it into the liquid phase fluid, and a catch tank for storing the liquid phase fluid delivered from the condenser. The expander and the condenser are connected via a first pipe arranged at a position where travel wind hits it. With the first pipe, a condensed water tank is communicated at its lower side for storing the liquid phase fluid condensed inside the first pipe. The condensed water tank is connected to the catch tank via a second pipe.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a waste heat recovery apparatus, and more particularly to a waste heat recovery apparatus that recovers waste heat of an internal combustion engine using a Rankine cycle system.

  Patent Document 1 discloses a technique related to a Rankine cycle system that recovers waste heat accompanying the operation of an internal combustion engine. In this Rankine cycle system, the liquid phase fluid is boiled by the waste heat of the engine and changed into steam (gas phase fluid), the gas phase fluid is superheated by a superheater, and the gas phase fluid after being heated is expanded. The expanded gas phase fluid is condensed and returned to the liquid phase fluid.

JP 2011-202584 A Japanese Patent No. 5376046

  The gas-phase refrigerant (gas-phase fluid) sent from the expander is sent to the condenser via the pipe and is changed into a liquid-phase refrigerant (liquid-phase fluid). However, the gas phase fluid also condenses in the piping in the process of being delivered to the condenser. In particular, when the piping is arranged so as to directly hit the traveling wind, a large amount of condensed water is generated in the piping. Therefore, a configuration for preventing the generated condensed water from staying is required. In this regard, in the technique of the above-mentioned Patent Document 1, no countermeasure is taken against the condensed water generated in the pipe, and there is room for improvement.

  The present invention has been made in view of the above-described problems. In a waste heat recovery apparatus that recovers waste heat of an internal combustion engine by a Rankine cycle, the refrigerant condensed in a pipe connecting an expander and a condenser is used. An object of the present invention is to provide a waste heat recovery device that can efficiently recover.

  The present invention includes a boiling device for vaporizing refrigerant, a gas-liquid separator for separating a gas-liquid two-phase refrigerant sent from the boiling device into a gas phase fluid and a liquid phase fluid, and a gas-liquid separator. A superheater that superheats the gas phase fluid to be heated by exchanging heat with the exhaust of the internal combustion engine, an expander that recovers thermal energy by expanding the gas phase fluid that has passed through the superheater, and a gas phase fluid that has passed through the expander A waste heat recovery apparatus including a condenser that condenses and returns the liquid phase fluid and a catch tank that stores the liquid phase fluid sent from the condenser is an object. In this waste heat recovery apparatus, the expander and the condenser are connected by a first pipe, and the first pipe is disposed at a location where the traveling wind hits. And the condensed water tank which stores the liquid phase fluid condensed inside the 1st piping is connected to the 1st piping from the lower part, and the condensed water tank is connected to the catch tank by the 2nd piping.

  According to this invention, the 1st piping which connects an expander and a condenser is arrange | positioned in the location where driving | running | working wind hits. For this reason, in the first pipe, the vapor phase fluid is condensed and a liquid phase fluid is generated. In the waste heat recovery apparatus of the present invention, the liquid phase fluid generated in the first pipe flows downward and is stored in the condensed water tank. Then, the liquid phase fluid stored in the condensed water tank is returned to the catch tank via the second pipe. Thereby, since the liquid phase fluid produced | generated in the 1st piping can be returned to a catch tank, it can suppress effectively that a liquid phase refrigerant continues staying in a 1st piping.

It is a figure which shows the structure of the Rankine cycle system of Embodiment 1 of this invention. It is an internal block diagram which shows the example of arrangement | positioning of each component at the time of mounting a Rankine-cycle system in FF vehicle provided with an exhaust system in the front side with respect to the advancing direction of a vehicle. It is the perspective view which extracted the structure from the evaporation part in FIG. 2, and the power recovery part, and showed the positional relationship. It is the perspective view which extracted the structure from the power recovery part in FIG. 2 to the condensation part, and showed the positional relationship. It is the side view which extracted the structure from the power recovery part in FIG. 2 to the condensation part, and showed the positional relationship. It is an internal block diagram which shows the example of arrangement | positioning of each component at the time of mounting a Rankine-cycle system in FF vehicle provided with an exhaust system in the back side with respect to the advancing direction of a vehicle. It is an internal block diagram which shows the example of arrangement | positioning of each component at the time of mounting a Rankine-cycle system in FR vehicle which set the engine vertically with respect to the advancing direction of a vehicle.

  Embodiments of the present invention will be described below with reference to the drawings. However, the same reference numerals are given to common elements in the drawings, and redundant description is omitted. In addition, in the embodiment shown below, when referring to the number of each element, quantity, quantity, range, etc., unless otherwise specified or clearly specified in principle, the reference However, the present invention is not limited to these numbers. Further, the structures described in the embodiments described below are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

Embodiment 1 FIG.
1. Configuration of Rankine Cycle System FIG. 1 is a diagram illustrating a configuration of a Rankine cycle system 100 according to the first embodiment. The Rankine cycle system 100 of the first embodiment includes an internal combustion engine (engine) 10 and is configured as a waste heat recovery device that recovers waste heat of the engine 10. The Rankine cycle system 100 is mounted together with the engine 10 in an engine compartment of a vehicle, and an upper opening is covered with a bonnet 1. There is no limitation on the type and structure of the engine 10. However, the cylinder block and the cylinder head of the engine 10 are formed with a refrigerant flow path (not shown) through which the refrigerant circulating in the engine 10 flows. The refrigerant flow path includes a water jacket surrounding the cylinder. The engine 10 is cooled by heat exchange with the refrigerant flowing through the refrigerant flow path. In the present embodiment, water is used as the refrigerant.

  The engine 10 is cooled by boiling the refrigerant flowing through the refrigerant flow path with the waste heat of the engine 10 and evaporating a part thereof. That is, the refrigerant flow path functions as a boiling device that boiles the liquid-phase refrigerant flowing through the inside by the heat of the engine 10. The configuration of the refrigerant flow path is not particularly limited as long as it is a passage that can flow through the engine 10. Moreover, the refrigerant | coolant distribute | circulated to a refrigerant | coolant flow path should just be a liquid phase fluid at normal temperature, should just be boiled with the heat | fever of the engine 10 and change to a gaseous phase fluid, and is not limited to water.

  The refrigerant flow path of the engine 10 is connected to the gas-liquid separator 16 via the refrigerant pipe 14. When the refrigerant is boiled by the heat of the engine 10, the liquid phase fluid is discharged from the refrigerant flow path together with the gas phase fluid. The gas-liquid separator 16 separates the gas-liquid two-phase refrigerant that has flowed into the gas-liquid separator 16 into a liquid-phase fluid and a gas-phase fluid. The gas-liquid separator 16 is connected to the first water pump 20 via the refrigerant pipe 18. The liquid phase fluid separated by the gas-liquid separator 16 flows into the first water pump 20 via the refrigerant pipe 18 and is sent to the refrigerant flow path by the first water pump 20.

  The Rankine cycle system 100 includes an exhaust heat recovery unit 13. The refrigerant flow path is also connected to the exhaust heat recovery device 13 via the refrigerant pipe 11. A liquid phase fluid is introduced into the exhaust heat recovery device 13 from the refrigerant flow path. The introduced liquid phase fluid is overheated by heat exchange with the exhaust gas flowing through the exhaust passage 22 and boils, and a part thereof becomes steam. The vapor phase fluid that has become vapor is introduced into the gas-liquid separator 16 through the refrigerant pipe 15.

  The gas-liquid separator 16 is connected to the superheater 30 via the refrigerant pipe 28. The superheater 30 is provided upstream of the exhaust heat recovery device 13 in the exhaust passage 22 of the engine 10. In the gas-liquid separator 16, since the gas phase fluid and the liquid phase fluid coexist, the gas phase fluid is saturated vapor. The gas-phase fluid that has entered the superheater 30 becomes superheated steam by absorbing the exhaust heat transmitted from the wall surface of the exhaust passage 22.

  The superheater 30 is connected to a turbine 34 that is an expander via a refrigerant pipe 32. In the turbine 34, the vapor phase fluid (superheated steam) sent from the superheater 30 is expanded to recover thermal energy. A supersonic nozzle (not shown) is provided at a connection portion between the refrigerant pipe 32 and the turbine 34. The gas phase fluid is jetted from the supersonic nozzle to the turbine 34 to rotate the turbine 34. The rotation of the turbine 34 is transmitted to the output shaft of the engine 10 via a speed reducer (not shown). That is, the thermal energy recovered by the turbine 34 is used for assisting the engine 10. However, it is also possible to drive the generator by the turbine 34 and store the generated electricity in the storage battery.

  The gas phase fluid expanded by the turbine 34 is sent to the condenser (condenser) 40 through the refrigerant pipe 36 (first pipe). Note that the liquid-phase fluid generated by the condensation of the gas-phase fluid in the middle of the refrigerant pipe 36 is temporarily stored in a condensed water tank 38 that communicates with the refrigerant pipe 36 from below. Details of the condensed water tank 38 will be described later. The liquid phase fluid in the condensed water tank 38 is sent to a catch tank 44 described later via a refrigerant pipe 39 (second pipe). A discharge control valve 37 is arranged in the middle of the refrigerant pipe 39. The gas-phase fluid sent to the condenser 40 is cooled and condensed by the condenser 40 and returned to the liquid-phase fluid. The liquid phase fluid generated by the condensation of the gas phase fluid is sent from the condenser 40 to the catch tank 44 via the refrigerant pipe 42 and temporarily stored in the catch tank 44. The catch tank 44 is connected to the first water pump 20 via the refrigerant pipe 46. A second water pump 48 is provided in the refrigerant pipe 46. The second water pump 48 is a pump for sending the liquid phase fluid stored in the catch tank 44 to the first water pump 20. According to such a configuration, the liquid-phase fluid stored in the catch tank 44 is sent to the engine 10 by driving the second water pump 48. The lower end of the catch tank 44 is connected to the lower end of the refrigerant tank 52 via the refrigerant pipe 50. In addition, a refrigerant pipe 54 whose end is connected to the upper end of the condenser 40 is connected to the upper end of the refrigerant tank 52.

2. Characteristic Arrangement of Rankine Cycle System The above components constituting the Rankine cycle system 100 include a steam generation unit that generates steam (gas phase fluid) from a liquid phase refrigerant (liquid phase fluid), and the steam into a liquid phase refrigerant. And the condensing part to be condensed. The steam generation unit is a component that forms a refrigerant path from the refrigerant sent from the engine 10 to the turbine 34 as a power recovery unit. For example, the gas-liquid separator 16, the superheater 30, and the exhaust heat recovery unit 13. , And refrigerant tubes 11, 14, 28, 32, and the like. On the other hand, the condensing unit is a component that constitutes a path for the refrigerant sent from the turbine 34 to return to the engine 10. For example, the condensing water tank 38, the condenser 40, the catch tank 44, and the refrigerant pipes 36, 42, 46 are used. Etc.

  Here, when the vehicle travels, traveling wind is introduced into the engine compartment from the front side of the vehicle. The introduced traveling wind directly hits the capacitor 40 disposed at the forefront. For this reason, in the front view of the vehicle, an area where the traveling wind does not directly hit is formed on the rear side overlapping the capacitor 40. On the other hand, since the traveling wind is not blocked by the capacitor 40 in the lower region of the capacitor 40, the traveling wind directly hits each component.

  In the Rankine cycle system 100 of the first embodiment, the steam generating unit is arranged in a region where the traveling wind does not directly hit, and the condensing unit is arranged in a region where the traveling wind directly hits. Hereinafter, the arrangement of the Rankine cycle system 100 in the case of an FF vehicle (front engine front wheel drive vehicle) in which the engine 10 is placed horizontally with respect to the traveling direction of the vehicle will be described in more detail.

  FIG. 2 is an internal configuration diagram illustrating an arrangement example of each component when a Rankine cycle system is mounted on an FF vehicle having an exhaust system on the front side with respect to the traveling direction of the vehicle. Note that FIG. 2 shows a view of the arrangement of main components among the components constituting the Rankine cycle system 100 in FIG. 1 as viewed from the side with respect to the traveling direction of the vehicle. FIG. 3 is a perspective view showing the positional relationship by extracting the configuration from the evaporation unit to the power recovery unit in FIG. FIG. 4 is a perspective view showing the positional relationship by extracting the configuration from the power recovery unit to the condensing unit in FIG.

  As shown in FIGS. 2 and 3, the components constituting the steam generator are arranged in a region between the exhaust system side of the engine 10 and the condenser 40. This region is blocked by cool running air by the condenser 40 and becomes hot by the exhaust heat of the engine 10. For this reason, it can suppress that a steam generation part is cooled and a vapor | steam amount reduces.

  Moreover, as shown in FIG.2 and FIG.4, the components which comprise a condensation part are arrange | positioned in the site | part which a driving | running | working wind directly hits. More specifically, the capacitor 40 is disposed on the forefront of the vehicle. Further, the refrigerant pipe 36 connects the steam outlet of the turbine 34 and the upper part of the condenser 40 through a region that is lateral to the condenser 40 in a front view of the vehicle. The catch tank 44 is disposed in a region below the condenser 40, and the refrigerant pipe 42 connects the lower part of the condenser 40 and the upper part of the catch tank 44. According to such a structure, since the components which comprise a condensation part can be cooled effectively with driving | running | working wind, condensation of a refrigerant | coolant can be accelerated | stimulated.

  The Rankine cycle system 100 according to the first embodiment includes a condensed water tank 38 as a characteristic configuration. FIG. 5 is a side view showing the positional relationship by extracting the configuration from the power recovery unit to the condensing unit in FIG. 2. As shown in FIGS. 4 and 5, the turbine 34 has a steam outlet (that is, a connection portion of the refrigerant pipe 36) provided at the lowermost end of the turbine 34. The steam outlet of the turbine 34 is located below the lower end of the condenser 40. The condensed water tank 38 is arranged at a position lower than the bottom of the outlet of the turbine 34. According to such a configuration, the refrigerant pipe 36 after the steam outlet of the turbine 34 is actively cooled by the traveling wind. At this time, the liquid phase fluid generated inside the refrigerant pipe 36 flows into the condensed water tank 38 located below and is stored. Thereby, even if it is the structure where the refrigerant | coolant pipe | tube 36 hits driving | running | working wind, the situation where a liquid phase fluid continues staying in the refrigerant | coolant pipe | tube 36 is avoided.

  Further, as shown in FIG. 5, the catch tank 44 is disposed further below the bottom of the condensed water tank 38. The lower end of the condensed water tank 38 is connected to the catch tank 44 via the refrigerant pipe 39. A discharge control valve 37 is disposed in the refrigerant pipe 39. When the discharge control valve 37 is opened during the Rankine cycle operation, the refrigerant in the condensed water tank 38 is sent into the catch tank 44 due to a pressure difference. Even when the Rankine cycle is stopped, the refrigerant in the condensed water tank 38 is sent into the catch tank 44 located further downward by opening the discharge control valve 37. The refrigerant introduced into the catch tank 44 is sent again to the engine 10 through the refrigerant pipe 46. Thereby, the refrigerant condensed in the refrigerant pipe 36 can be reliably recovered.

  Further, the coolant stored in the catch tank 44 is sent to the engine 10 by the second water pump 48. The refrigerant is decompressed in the process of passing through the condenser 40 and being cooled. For this reason, the second water pump 48 sucks out the refrigerant from the negative pressure environment, and the reduced-pressure boiling occurs at the inlet of the second water pump 48. As shown in FIG. 5, according to the configuration in which the catch tank 44 is disposed at the lowermost position, it is possible to earn a head in the catch tank 44, so that the gas is prevented from biting into the second water pump 48 and condensed. It becomes possible to reliably collect the refrigerant.

  The condensed water tank 38 is preferably connected to the vicinity of the steam outlet of the turbine 34 in the refrigerant pipe 36. As a result, a large pressure difference between the condensed water tank 38 and the catch tank 44 can be secured, so that the refrigerant flow from the condensed water tank 38 to the catch tank 44 can be promoted.

3. Others In the first embodiment described above, the case where the Rankine cycle system 100 is mounted on an FF vehicle in which the engine 10 is placed horizontally with respect to the traveling direction of the vehicle has been described. However, the Rankine cycle system 100 according to the present invention can be mounted on other types of engines. FIG. 6 is an internal configuration diagram showing an arrangement example of each component when the Rankine cycle system is mounted on an FF vehicle having an exhaust system on the rear side with respect to the traveling direction of the vehicle. FIG. 7 is an internal configuration diagram showing an arrangement example of each component when the Rankine cycle system is mounted on an FR vehicle (front engine rear wheel drive vehicle) in which the engine is installed vertically with respect to the traveling direction of the vehicle. . In addition, in FIG. 6, the figure which looked at arrangement | positioning of the main components among the components which comprise the Rankine cycle system 100 in FIG. 1 from the side surface side with respect to the advancing direction of a vehicle is shown. Further, FIG. 7 shows a view of the arrangement of the main components among the components constituting the Rankine cycle system 100 in FIG. 1 as viewed from the front side with respect to the traveling direction of the vehicle.

  Even in other types of engines as shown in FIGS. 6 and 7, it is possible to suppress the steam generator from being cooled by the traveling wind by disposing the steam generator behind the condenser 40. . Moreover, since the condensing part is arrange | positioned in the area | region where driving | running | working wind directly hits, cooling is accelerated | stimulated. Furthermore, since the liquid-phase refrigerant generated in the refrigerant pipe 36 is efficiently recovered into the condensed water tank 38, the liquid-phase refrigerant is prevented from staying in the refrigerant pipe 36.

1 Bonnet 10 Engine 11, 14, 15, 18, 28, 32, 42, 46, 50, 54 Refrigerant pipe 36 Refrigerant pipe (first pipe)
39 Refrigerant pipe (second pipe)
13 Exhaust heat recovery device 16 Gas-liquid separator 20 First water pump 22 Exhaust passage 30 Superheater 34 Turbine (expander)
37 Discharge control valve 38 Condensed water tank 40 Condenser 44 Catch tank 48 Second water pump 52 Refrigerant tank 100 Rankine cycle system

Claims (1)

A boiling device that vaporizes the refrigerant, a gas-liquid separator that separates a gas-liquid two-phase refrigerant sent from the boiling device into a gas phase fluid and a liquid phase fluid, and a gas sent from the gas-liquid separator. A superheater that superheats the phase fluid by heat exchange with the exhaust of the internal combustion engine, an expander that recovers thermal energy by expanding the gas phase fluid that has passed through the superheater, and a gas phase fluid that has passed through the expander In a waste heat recovery apparatus comprising: a condenser that condenses and returns the liquid phase fluid; and a catch tank that stores the liquid phase fluid sent from the condenser.
The expander and the condenser are connected by a first pipe,
The first pipe is arranged at a location where the traveling wind hits,
A condensed water tank communicating from the lower side of the first pipe to the first pipe and storing a liquid phase fluid condensed inside the first pipe;
A second pipe connecting the condensed water tank and the catch tank;
A waste heat recovery apparatus comprising:

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