JP5012588B2 - Waste heat recovery device - Google Patents

Description

  The present invention relates to a waste heat recovery device, and more particularly, to a waste heat recovery device that recovers waste heat from a heat source as power of a drive device using an engine as a heat source.

A waste heat recovery device that includes a turbine, a compressor, and an exhaust cooling device installed between them, and that converts exhaust heat into power, newly installs an absorption chiller that uses the waste heat of engine cooling water to cool the exhaust Some refrigerants dissipate heat by the evaporator of this absorption refrigerator (see Patent Document 1).
JP 2002-188438 A

  By the way, as in the technique of the above-mentioned Patent Document 1, when the absorption refrigerator is used for heat radiation of the cooling medium for cooling the exhaust gas discharged from the turbine, the configuration of the absorption refrigerator is a rectifier, a condenser, Since it is complicated, such as having an absorber and an evaporator, the size is increased and a large space is required even if it is mounted on an automobile.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a waste heat recovery device that can be easily mounted even in an automobile and does not take up space.

In the present invention, the exhaust from the engine (1) is led to the turbine (2) and expanded to a negative pressure which is lower than the atmospheric pressure, and then led to the heat exchanger (3) to be cooled. In a waste heat recovery device that extracts exhaust gas as power by compressing the exhaust gas from a negative pressure to an atmospheric pressure with a compressor (4) coaxial with the turbine (2) and discharging it, cooling water is discharged to the water jacket (12) of the engine. A cooling device including at least a water pump (14) to be supplied and a radiator (13) for cooling the cooling water discharged from the water jacket (12); an outlet of the water pump (14); and an inlet of the radiator (13) A first passage (41) to be connected and a second passage (branch from the first passage (41) and connected to one end of the pipe (3B) in the heat exchanger through which the cooling water flows ( 42 A third passage (43) connecting the other end of the pipe (3B) and the engine outlet of the water jacket (12), and the first passage (41) of the second passage (42). And a three-way valve (44) provided at a branch portion from which the communication between the outlet of the water pump (14) and the first and second passages (41, 42) is interrupted when the engine is cold. The communication between the outlet of the water pump and the first passage (41) is interrupted after completion of warming up of the engine so that the first passage (41) and the second passage (42) are communicated with each other. The three-way valve (44) is controlled so that the outlet of the water pump (14) communicates with the second passage (42).

According to the present invention, exhaust from an engine is led to a turbine and expanded to a negative pressure and then led to a heat exchanger to be cooled, and the cooled exhaust is cooled from a negative pressure to an atmospheric pressure by a compressor coaxial with the turbine. In a waste heat recovery apparatus for extracting power as a power by compressing and discharging, a cooling apparatus including at least a water pump that discharges cooling water and supplies the cooling water to an engine water jacket, and a radiator that cools the cooling water discharged from the water jacket And a first passage connecting the water pump outlet and the radiator inlet, and a second branch branched from the first passage and connected to one end of a pipe in the heat exchanger through which cooling water flows. , A third passage connecting the other end of the pipe line and the engine outlet of the water jacket, and a branch portion of the second passage from the first passage. The water pump outlet and the first and second passages are blocked from each other and the first passage and the second passage are communicated with each other when the engine is cold. After the engine is warmed up, the three-way valve is controlled so that the communication between the water pump outlet and the first passage is interrupted and the water pump outlet and the second passage are communicated. It becomes possible to circulate the engine cooling water heated by the exhaust heat in the heat exchanger during the cold operation to the water jacket, so that the mountability to the automobile is improved and the completion of the warm-up of the engine can be further accelerated. In addition, since the cooling water heated in the heat exchanger 3 returns to the radiator 13 to dissipate heat by switching the three-way valve after the engine warm-up is completed, the engine cooling performance after the engine warm-up is completed is deteriorated. Without waste heat recovery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a waste heat recovery apparatus of a first reference example according to the present invention. An exhaust pipe 11 of the engine 1 includes a turbine 2 for expanding the exhaust from the engine 1 to a negative pressure, a heat exchanger 3 for cooling the exhaust discharged from the turbine 2 under a negative pressure, and a coaxial with the turbine 1. And a compressor 4 for compressing exhaust gas cooled by the heat exchanger 3 from negative pressure to normal pressure (atmospheric pressure), and a generator 8 is provided coaxially with the turbine 1 and the compressor 4. . The generator 8 works by driving the turbine 2 with the exhaust energy, whereby the exhaust energy is recovered as electric energy. In this method, waste heat is recovered by obtaining a driving force by a so-called reverse Brayton cycle. FIG. 4 shows a basic configuration of the waste heat recovery apparatus of the present invention. Here, the “negative pressure” means a pressure lower than the atmospheric pressure.

  The engine 1 is provided with a cooling device including a water jacket 12, a radiator 13, a water pump 14, a thermostat 15, and a bypass passage 16 formed so as to cover the cylinder block and the cylinder head.

In this case, in the first reference example , the heat exchanger 3 for cooling the exhaust from the turbine 2 and the radiator 13 for cooling the engine coolant are integrated. That is, the heat exchanger 3 is a direct heat exchanger that exchanges heat between the high-temperature exhaust gas and the low-temperature cooling medium, and the pipe line 3A through which the exhaust gas that enters at a high temperature and releases heat flows. And a conduit 3B through which a cooling medium that enters in a low temperature state and receives heat flows. On the other hand, the radiator 13 is provided with a tube 13A for cooling the high-temperature cooling water discharged from the engine outlet 12A of the water jacket 12 with outside air. A second tube 13B is provided in parallel with the tube 13A. The second tube 13 </ b> B and the pipe line 3 </ b> B in the heat exchanger 3 are connected in series by two passages 21 and 22 to form one circulation path 23. In other words, the cooling medium circulation path 23 is constituted by the pipe 3 </ b> B in the heat exchanger 3, the passage 21, the second tube 13 </ b> B in the radiator 13, and the passage 22.

  The circulation path 23 is provided with a pump 24 for circulating the cooling medium in the circulation path 23. The operation and non-operation of the pump 24 are controlled by an engine controller (not shown).

In the first reference example , a circulation path 23 that circulates the cooling medium that flows to the heat exchanger 3 is provided separately from the engine cooling water circulation path. Therefore, the cooling medium used to circulate the circulation path 23 is engine cooling water. Not limited to. Of course, engine cooling water may be used.

  If comprised in this way, a cooling medium will flow through the circulation path 23 by driving the pump 24 by an engine controller during an engine driving | operation. The hot exhaust gas flowing through the pipe line 3 </ b> A in the heat exchanger 3 exchanges heat with the cooling medium flowing through the other pipe line 3 </ b> B of the heat exchanger 3, drops in temperature, and is sent to the compressor 4. On the other hand, the cooling medium flowing through the pipe line 3B in the heat exchanger 3 rises in temperature by heat exchange with the high-temperature exhaust gas flowing through the pipe line 3A and goes out of the heat exchanger 3. The heated cooling medium is guided from the passage 22 to the second tube 13B in the radiator 13 and cooled by outside air. The cooled cooling medium goes out of the radiator 13, returns to the pipe 3B of the heat exchanger 3 through the passage 21, and rises again with heat from the exhaust gas passing through the pipe 3A. In this way, the exhaust gas flowing through the pipe 3 </ b> A in the heat exchanger 3 is cooled by the cooling medium flowing through the circulation path 23.

According to the first reference example , the exhaust from the engine 1 is led to the turbine 2 and expanded to a negative pressure and then cooled to the heat exchanger 3, and the cooled exhaust is compressed by the compressor 4 coaxial with the turbine 2. In the waste heat recovery apparatus that extracts as power by compressing and discharging from negative pressure to atmospheric pressure, a water pump 14 that discharges cooling water and supplies it to the water jacket 12 of the engine, and cooling water discharged from the water jacket 12 A cooling device including at least a radiator 13 for cooling the cooling medium, and a cooling medium for cooling the exhaust gas exiting the turbine 2 is allowed to flow to the heat exchanger 3 and to the heat exchanger 3 separately from the cooling water. Is also cooled by the radiator 13. That is, since the heat exchanger 3 is integrated with the radiator 13, weight reduction and space saving can be achieved in the entire apparatus, so that mounting on an automobile is improved.

FIG. 2 shows a schematic configuration of the waste heat recovery apparatus of the second reference example , and the same parts as those in FIG.

In the second reference example , the engine cooling water used in the engine cooling device is used as it is as a cooling medium for cooling the exhaust from the turbine 2 in the heat exchanger 3. That is, the engine coolant passes through the water pump 14 after exiting from the outlet 13C of the radiator 13 and travels toward the water jacket 12 in the engine body. However, the engine coolant branches downstream of the water pump 14 and flows into the heat exchanger 3. A branch passage 31 connected to one end 3C (right end) of the conduit 3B and a return passage 32 connected to the other end 3D (left end) of the conduit 3B and joined to the inlet 13D of the radiator 13 are provided.

  If comprised in this way, the cold cooling water which came out of the radiator exit 13C will flow into the water jacket 12 in an engine main body. Cooling water in the water jacket 12 heated by heat exchange with the cylinder block and the cylinder head goes out of the engine body from the engine outlet 12A, flows through the tube 13A in the radiator 13 from the inlet 13D of the radiator 13, and dissipates heat here. . Further, the cold cooling water that has exited from the radiator outlet 13 </ b> C flows through the pipe 3 </ b> B in the heat exchanger 3 through the branch passage 31 from the outlet of the water pump 14. The cooling water in the pipe 3B heated by the exhaust gas flowing through the pipe 3A in the heat exchanger 3 also flows through the tube 13A in the radiator 13 from the inlet 13D of the radiator 13 through the return path 32 and radiates heat. That is, an engine coolant circulation path is formed by four of the tube 13A in the radiator 13, the branch passage 31, the pipe 3B in the heat exchanger 3, and the return passage 32.

According to the second reference example , the exhaust from the engine 1 is guided to the turbine 2 and expanded to a negative pressure and then cooled to the heat exchanger 3, and the cooled exhaust is compressed by the compressor 4 coaxial with the turbine 2. In the waste heat recovery apparatus that extracts as power by compressing and discharging from negative pressure to atmospheric pressure, a water pump 14 that discharges cooling water and supplies it to the water jacket 12 of the engine, and cooling water discharged from the water jacket 12 And a cooling device including at least a radiator 13 for cooling the cooling water. The cooling water for cooling the exhaust discharged from the turbine 2 is supplied to the heat exchanger 3, and the cooling water is cooled by the radiator 13. That is, since the cooling medium (cooling water) can be integrated into one system, the mountability to the automobile is improved and the apparatus can be further simplified.

  Moreover, since the heat dissipation capability of the radiator 13 can be used effectively during low-load traveling, the entire device can be reduced in weight and space.

FIG. 3 shows a schematic configuration of the waste heat recovery apparatus according to the first embodiment of the present invention, and the same parts as those in FIG.

The first embodiment is the same as the second reference example in that the engine cooling water is used as a cooling medium for cooling the exhaust from the turbine 2 in the heat exchanger 3, but the engine 1 is warmed up when the engine is cooled. The machine is assisted and the completion of warm-up of the engine 1 is promoted. That is, the first passage 41 that branches from the outlet of the water pump 14 and joins the inlet of the radiator 13, and the first passage 41 branches from a position near the outlet of the water pump 14 and branches in the heat exchanger 3. A second passage 42 connected to one end 3C (right end) of the pipe line 3B and a position 12B (or the water jacket 12) close to the engine outlet 12A of the water jacket 12 connected to the other end 3D (left end) of the pipe line 3B. And a third passage 43 that merges with the engine outlet 12A), and a three-way valve 44 is interposed at a branch portion of the second passage 42 from the first passage 41.

  The three-way valve 44 shuts off the communication between the outlet of the water pump 14 and the two passages 41, 42 when the engine is cold, and communicates the second passage 42 and the first passage 41. The communication between the outlet of the water pump 14 and the first passage 41 is cut off, and the outlet of the water pump 14 and the second passage 42 are communicated. The three-way valve 44 is switched by an engine controller (not shown).

  With this configuration, when the engine is cold, the three-way valve 44 blocks communication between the outlet of the water pump 14 and the two passages 41 and 42 and connects the second passage 42 and the first passage 41. Further, the thermostat 15 is closed when the engine is cold. At this time, the engine coolant is warmed by the water jacket 12 and exits from the engine outlet 12A at the rear end (left end) of the cylinder block, and then returns to the water pump 14 inlet through the bypass passage 16, By repeating the cycle of warming with the water jacket 12 again, the temperature rises and the temperature of the engine body also rises. A part of the cooling water exits from the position 12B near the engine outlet 12A of the water jacket 12 and flows through the third passage 43 through the pipe 3B in the heat exchanger 5, where the heat from the exhaust is removed. Receive and heat up. The cooling water warmed out by the heat exchanger 3 is returned from the second passage 42 and the three-way valve 44 to the inlet of the water pump 14 through the first passage 41 and the tube 13A in the radiator 13, and again into the water pump. A cycle in which the jacket 12 exits from the position 12B near the engine outlet 12A and flows through the third passage 43 through the pipe 3B in the heat exchanger 5 where the temperature is raised by receiving heat from the exhaust. repeat. In this way, the engine coolant temperature rises not only by heat exchange with the cylinder block and cylinder head, but also by the high-temperature exhaust from the turbine 2 in the heat exchanger 3, and accordingly, the engine 1 is increased by that amount. The warm-up completion can be accelerated.

When the warm-up of the engine 1 is completed, the three-way valve 44 blocks communication between the outlet of the water pump 14 and the first passage 41 and connects the outlet of the water pump 14 and the second passage 42. The flow of the cooling water at this time is the same as in the second reference example . That is, the cold cooling water from the water pump 14 flows through the pipe 3B in the heat exchanger 3 through the three-way valve 44 and the second passage 42, where heat is taken away from the exhaust from the turbine 2, and the water jacket 12 returns to the water jacket 12 from a position 12B near the engine outlet 12A. From here, together with the high-temperature cooling water coming out from the engine body to the engine outlet 12A of the water jacket 12, it flows into the radiator 13 and is cooled, and then returned to the water pump 14 inlet.

According to the first embodiment (the invention described in claim 1 ), the exhaust from the engine 1 is led to the turbine 2 and expanded to a negative pressure, and then led to the heat exchanger 3 to be cooled. A water pump 14 that discharges cooling water and supplies it to an engine water jacket 12 in a waste heat recovery device that extracts exhaust gas as power by compressing the exhaust gas from a negative pressure to an atmospheric pressure by a compressor 4 coaxial with the turbine 2 , A cooling device including at least a radiator 13 that cools the cooling water discharged from the water jacket 12, a first passage 41 that connects the outlet of the water pump 14 and the inlet of the radiator 13, and a branch from the first passage 41. The second passage 42 connected to the one end 3C of the conduit 3B in the heat exchanger through which the cooling water flows, the other end 3D of the conduit 3B, and the end of the water jacket 12 are connected. And a three-way valve 44 provided at a branch portion from the first passage 41 of the second passage 42 to connect the position 12B close to the engine outlet 12A. 14 after the engine warm-up is completed so that the communication between the 14 outlet and the first and second passages 41 and 42 is blocked and the first passage 41 and the second passage 42 are communicated. Since the three-way valve 44 is controlled so that the communication between the first passage 41 and the outlet of the water pump 14 is communicated with the second passage 42, the exhaust heat is generated in the heat exchanger 3 when the engine is cold. It is possible to circulate the warmed engine cooling water to the water jacket 12, so that the mountability to the automobile is improved and the warm-up completion of the engine can be further accelerated. In addition, since the cooling water heated in the heat exchanger 3 returns to the radiator 13 to dissipate heat by switching the three-way valve 44 after the engine warm-up is completed, the engine cooling performance after the engine warm-up is completed is deteriorated. Waste heat can be recovered without any problems.

Although 1st Embodiment demonstrated the case where the position 12B near the engine exit 12A of the water jacket 12 and the left end 3D of the pipe line 3B in the heat exchanger 3 were connected, it is not restricted to this. For example, there is one in which high-temperature cooling water from the engine outlet 12A of the water jacket 12 is led to a heater (heat exchanger) for heating, and the cooling water whose temperature is reduced by radiating here is returned to the upstream of the water pump 14. In such a thing, what is necessary is just to connect a heater exit and the left end 3D of the pipe line 3B in the heat exchanger 3. FIG.

The schematic block diagram of the waste-heat recovery apparatus of the 1st reference example with respect to this invention. The schematic block diagram of the waste-heat recovery apparatus of the 2nd reference example . 1 is a schematic configuration diagram of a waste heat recovery apparatus according to a first embodiment of the present invention . The basic block diagram of the waste heat recovery apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine main body 2 Turbine 3 Heat exchanger 3A Pipe line 3B Pipe line 4 Compressor 8 Generator 11 Exhaust pipe 12 Water jacket 13 Radiator 13B 2nd tube 14 Water pump 23 Circulation path 31, 32 Passage 41 First passage 42 First 2 passages 43 3rd passage 44 Three-way valve

Claims (1)

The exhaust from the engine is led to the turbine and expanded to a negative pressure that is lower than the atmospheric pressure, then led to a heat exchanger to be cooled, and the cooled exhaust is cooled from a negative pressure to an atmospheric pressure by a compressor coaxial with the turbine. In the waste heat recovery device that takes out as power by compressing and discharging to
A cooling device that includes at least a water pump that discharges the cooling water and supplies the water jacket to the engine water jacket, and a radiator that cools the cooling water discharged from the water jacket ;
A first passage connecting the water pump outlet and the radiator inlet;
A second passage branched from the first passage and connected to one end of a conduit in the heat exchanger through which cooling water flows;
A third passage connecting the other end of the pipe line and the engine outlet of the water jacket;
A three-way valve provided at a branch portion of the second passage from the first passage;
With
After completion of warming up of the engine, the communication between the outlet of the water pump and the first and second passages is interrupted and the first passage and the second passage are communicated when the engine is cold-started. The waste heat recovery apparatus , wherein the three-way valve is controlled so that communication between the water pump outlet and the first passage is blocked and the water pump outlet and the second passage are in communication .

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