JP2009250139A - Engine waste heat collection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine waste heat collection system, quickly operable when restarting an engine. <P>SOLUTION: This engine waste heat collection system 1 is constituted so as to collect steam energy of a working fluid heated by waste heat of an engine 2 by an energy collecting part 34. This engine waste heat collection system 1 has a working fluid condenser 35a for condensing steam passed through the energy collecting part 34 and coolers 35b and 35c for cooling the working fluid condenser 35a when stopping the engine 2. Thus, condensation performance of the steam of the working fluid by the working fluid condenser 35a can be secured even when stopping the engine 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine waste heat recovery system, that is, a system for recovering energy from engine waste heat.

  As this type of system, for example, a system described in JP-A-6-88523 is known. This system cools the engine with the heat of vaporization of the cooling water and converts the expansion energy of the steam generated with the cooling of the engine into mechanical energy, thereby reducing the energy from waste heat such as combustion heat and friction heat. It is comprised so that it can collect | recover. Specifically, this system includes a cylinder block, a heater, an expander, and a condenser.

  The cylinder block is provided with a water jacket to which cooling water is supplied. The heater is configured to heat the cooling water vapor flowing out of the water jacket by heat of exhaust gas. The expander is configured to convert expansion energy of steam that has passed through the heater into mechanical energy. The condenser is configured to condense the vapor into a liquid by cooling the vapor that has lost its energy and has become low pressure.

  In the engine waste heat recovery system having such a configuration, the cooling water is supplied to the water jacket. As a result, the cylinder block is cooled, and the cooling water evaporates in the water jacket to generate steam.

  This steam is further heated by the heater by heat exchange with the exhaust gas, and then supplied to the expander. Then, the steam expands in the expander. Thereby, mechanical energy is recovered.

  Thereafter, the low-pressure vapor that has lost energy flows into the condenser and is condensed into a liquid. Thus, the cooling water that has become liquid by being condensed in the condenser is supplied again to the water jacket.

Note that this type of system (so-called Rankine system) can be mounted on, for example, a hybrid vehicle (for example, Japanese Unexamined Patent Application Publication Nos. 2002-115573, 2004-239179, 2007-205283, and Japanese Unexamined Patent Application Publication No. 2007-205283). 2008-57340 publication etc.).
JP-A-6-88523 JP 2002-115573 A JP 2004-239179 A JP 2007-205283 A JP 2008-57340 A

  The above-described system is stopped while the engine is stopped (even if the vehicle is running when mounted on a hybrid vehicle). Then, the steam condensing operation by the condenser is also stopped while the engine is stopped. For this reason, when the engine is restarted, a situation may occur in which a sufficient amount of the cooling water is not ensured to operate the system again.

  In addition, if the capacity | capacitance of the reservoir tank which stores the said liquid cooling water is enlarged, the apparatus structure of the said system will enlarge, and the mounting property to the vehicle of the said system will deteriorate.

  The present invention has been made to solve such problems. That is, an object of the present invention is to provide an engine waste heat recovery system that can be operated promptly upon engine restart.

<Configuration>
The engine waste heat recovery system of the present invention includes an engine, an energy recovery unit, and a working fluid condenser. The energy recovery unit is configured to recover energy from the steam of the working fluid heated by the waste heat of the engine. The working fluid condenser is configured to condense the vapor that has passed through the energy recovery unit.

  The engine waste heat recovery system may further include an electric pump. The electric pump is interposed in the working fluid circulation path.

  The engine waste heat recovery system may further include a working fluid tank capable of storing the liquid working fluid. The working fluid tank is interposed in the circulation path downstream of the working fluid condenser in the flow direction of the working fluid.

  The engine waste heat recovery system may further include a working fluid amount output unit. The working fluid amount output unit is configured to generate an output corresponding to the amount of the liquid working fluid that can be supplied to the engine. Specifically, the working fluid amount output unit can be attached to the working fluid tank.

  The present invention is characterized in that the engine waste heat recovery system further includes a cooler capable of cooling the working fluid condenser when the engine is stopped.

  Here, the cooler may further include an air conditioning system condenser and / or an electric motor system coolant cooling unit. The air conditioning system condenser is configured to condense an air conditioning system refrigerant that is a refrigerant of an air conditioning system in a vehicle. The electric motor system refrigerant cooling unit is configured to cool an electric motor system refrigerant that is a refrigerant of an electric motor system in a hybrid vehicle.

  The engine waste heat recovery system may further include a control unit. The control unit controls the condensing operation state in the working fluid condenser when the engine is stopped according to the output of the working fluid amount output unit. Specifically, the control unit may be configured to control an operating state of the electric pump when the engine is stopped according to an output of the working fluid amount output unit. Alternatively, the control unit may be configured to control an operating state of the cooler when the engine is stopped according to an output of the working fluid amount output unit.

<Action>
In the engine waste heat recovery system of the present invention, the working fluid condenser is cooled by the cooler even when the engine is stopped (at this time, the electric pump can be driven).

  Specifically, for example, the condensing operation state (the operating state of the electric pump or the cooler) in the working fluid condenser when the engine is stopped is controlled according to the output of the working fluid amount output unit. That is, when it is determined by the output that the storage amount in the working fluid tank is less than a predetermined amount, the electric pump and the cooler are driven even when the engine is stopped.

<Effect>
According to the present invention, the vapor condensing performance of the working fluid by the working fluid condenser can be ensured even when the engine is stopped. Therefore, when the engine is restarted, a sufficient amount of the liquid working fluid can be secured for restarting the engine waste heat recovery system. Therefore, the system can be operated immediately upon restarting the engine.

  Further, even if the capacity of the working fluid tank is not excessively increased, a sufficient amount of the liquid working fluid can be secured sufficiently for restarting the engine waste heat recovery system. Therefore, good mountability of the system on the vehicle can be realized.

  Furthermore, by using the air-conditioning system condenser and the electric motor system coolant cooling section as the cooler, it is possible to realize further favorable mounting properties on the vehicle.

  Hereinafter, embodiments of the present invention (embodiments that the applicant considers best at the time of filing of the present application) will be described with reference to the drawings.

  In addition, the description about the following embodiment is specific to the extent possible, merely an example of the embodiment of the present invention in order to satisfy the description requirement (description requirement / practicability requirement) of the specification required by law. It is only what is described in. Therefore, as will be described later, it is quite natural that the present invention is not limited to the specific configurations of the embodiments described below. Various modifications that can be made to the present embodiment are listed together at the end, as they would interfere with the understanding of the consistent description of the embodiment if inserted during the description of the embodiment. .

<System configuration of the first embodiment>
FIG. 1 is a schematic configuration diagram of an engine waste heat recovery system 1 (hereinafter simply referred to as “system 1”) according to a first embodiment of the present invention. The system 1 of this embodiment is mounted on a hybrid vehicle. Referring to FIG. 1, the system 1 includes an engine 2, an energy recovery mechanism 3, a cooling water circulation path 4, an electronic control unit 5, and an electric motor system 6.

<< Engine >>
A crankshaft pulley 22 is attached to the crankshaft 21 provided in the engine 2. The crankshaft pulley 22 is configured to drive an endless belt-like drive transmission belt 22b. An exhaust pipe 23 is connected to the engine 2. Further, a temperature sensor 24 is attached to the engine 2. The temperature sensor 24 is configured to generate an output corresponding to the temperature of the engine 2 (for example, the temperature of the liquid coolant stored in the engine 2).

<< Energy recovery mechanism >>
The energy recovery mechanism 3 has the following configuration so as to cool the engine 2 with the cooling water as the working fluid of the present invention and to recover energy from the steam of the cooling water generated during the cooling. .

  The gas-liquid separator 31 is configured to gas-liquid-separate wet steam (in a state where moisture and steam coexist) generated by boiling cooling water in the engine 2. The radiator 32 is configured to cool the liquid cooling water separated from the steam by the gas-liquid separator 31 and the liquid cooling water in the engine 2 by heat exchange with the outside air.

  The superheater 33 is interposed in the exhaust pipe 23. The superheater 33 is configured to generate superheated steam by heating the steam that has passed through the gas-liquid separator 31 with the heat of the exhaust gas.

  The turbine 34 as an energy recovery unit of the present invention is configured to recover energy from superheated steam that has passed through the superheater 33. That is, a turbine pulley 34a is attached to the output shaft coupled to the rotor of the turbine 34, and this turbine pulley 34a is coupled to the crankshaft 21 via the drive transmission belt 22b and the crankshaft pulley 22 described above. Yes.

  The multi-function capacitor 35 is disposed in front of the radiator 32 so that it can be cooled better than the radiator 32 by receiving a cooler vehicle wind. The multi-function capacitor 35 includes an engine coolant condenser 35a, a hybrid radiator 35b, and an air conditioning condenser 35c.

  The engine coolant condenser 35a as the working fluid condenser of the present invention is a low-pressure coolant through the turbine 34 by heat exchange with outside air and cooling by the engine coolant condenser 35a and the hybrid radiator 35b as the cooler of the present invention. It is configured to condense the steam.

  The hybrid radiator 35b as an electric motor system refrigerant cooling unit of the present invention cools an electric motor system refrigerant that is a refrigerant for cooling the electric motor system 6 (specifically, an inverter provided therein) by heat exchange with outside air. Is configured to do. The air conditioning system condenser 35c is configured to condense the air conditioning system refrigerant, which is a refrigerant of an air conditioning system (not shown), by cooling it by heat exchange with the outside air. The engine coolant condenser 35a and the hybrid radiator 35b are driven under the control of the electronic control unit 5 even when the engine 2 is stopped, so that the engine coolant condenser 35a can be cooled.

  The catch tank 36 as a working fluid tank of the present invention is interposed in the coolant circulation path 4 on the downstream side in the coolant flow direction from the engine coolant condenser 35a. The catch tank 36 is configured to store liquid coolant that has passed through the engine coolant condenser 35a.

  The electric pump 37 is interposed between the bottom of the space (water jacket) in which the cooling water in the engine 2 can be stored in the cooling water circulation path 4 and the catch tank 36. In the present embodiment, the electric pump 37 is provided inside the engine 2.

  The bypass switching valve 38 is a so-called three-way valve, and has a state in which the gas-liquid separator 31 and the superheater 33 are connected and a state in which the gas-liquid separator 31 and the radiator 32 are connected by bypassing the superheater 33. It is configured to switch alternatively.

<< Cooling water circulation path >>
The cooling water circulation path 4 includes a cooling water supply path 41, a steam outlet path 42, a separated cooling water outlet path 43, a hot water outlet path 44, a cold water supply path 45, a turbine outlet path 46, a bypass path 47, A tank connection path 48.

  The cooling water supply path 41 is provided so as to connect the engine cooling water condenser 35a and the bottom of a space (water jacket) in which the cooling water in the engine 2 can be stored. A catch tank 36 and an electric pump 37 are interposed in the cooling water supply path 41 so as to be arranged in this order from the upstream side to the downstream side in the flow direction of the cooling water.

  The steam outlet path 42 is provided so as to connect the upper part of the above-described space in the engine 2 and the turbine 34. In the steam outlet path 42, the gas-liquid separator 31, the bypass switching valve 38, and the superheater 33 are arranged in this order from the upstream side to the downstream side in the flow direction of the cooling water steam. It is intervened.

  The separation cooling water outlet passage 43 is provided so as to connect the gas-liquid separator 31 and the radiator 32. An upstream end portion of the hot water outlet passage 44 is connected to the above-described space in the engine 2. The warm water outlet passage 44 is provided so as to merge with the separated cooling water outlet passage 43 at the downstream end thereof. The cold water supply path 45 is provided so as to connect the radiator 32 and the bottom of the above-described space in the engine 2.

  The turbine lead-out path 46 is provided so as to connect the turbine 34 and the engine coolant condenser 35a. The bypass passage 47 is provided so as to connect the bypass switching valve 38 and the radiator 32. The tank connection path 48 is provided so as to connect the upper end portion of the radiator 32 and the upper end portion of the catch tank 36. That is, the tank connection path 48 is provided so as to introduce liquid cooling water overflowing from the radiator 32 into the catch tank 36.

<< Electronic control unit >>
The electronic control unit 5 is electrically connected to sensors such as the temperature sensor 24 and operation units such as the electric pump 37 and the bypass switching valve 38. The electronic control unit 5 controls the operation of each operation unit described above based on the outputs from the various sensors described above.

<Operation of Engine Waste Heat Recovery System of First Embodiment>
Hereinafter, the operation of the system 1 of the present embodiment having the above-described configuration will be described with reference to FIG.

  The engine 2 stops when the vehicle is stopped or while the vehicle is traveling only by the output of the electric motor system 6. On the other hand, when the electric motor system 6 is started only when the electric motor system 6 is driven and when the electric vehicle system is stopped (especially when the electric motor system 6 needs to be cooled), the electric motor system 6 is cooled. In addition, the cooling operation by the hybrid radiator 35b is performed. At the time of starting the air conditioning system, the air conditioning system condenser 35c condenses the air conditioning system refrigerant.

<< When engine temperature is not high >>
When the engine 2 is being started and the temperature of the engine 2 is equal to or lower than a predetermined upper limit value (for example, 90 ° C.), the upstream side and the downstream side of the bypass switching valve 38 in the steam outlet passage 42 are communicated. At this time, communication between the bypass passage 47 and the steam outlet passage 42 upstream of the bypass switching valve 38 is blocked.

  In this state, when the electric pump 37 is driven, liquid cooling water in the catch tank 36 is supplied to the engine 2. As the cooling water boils inside the engine 2, wet steam is generated inside the engine 2. This wet steam is led out of the engine 2 through the steam lead-out path 42. Thereafter, the wet steam reaches the gas-liquid separator 31.

  In the gas-liquid separator 31, water droplets and steam are separated. The separated steam is led out downstream of the gas-liquid separator 31 in the steam lead-out path 42. On the other hand, the separated water droplets are sent to the radiator 32 via the separated cooling water lead-out path 43.

  The steam that has passed through the gas-liquid separator 31 is heated by the heat of the exhaust gas in the superheater 33 to become superheated steam. When this superheated steam is introduced into the turbine 34, energy is recovered by the turbine 34. The recovered energy is transmitted to the crankshaft 21 via the turbine pulley 34a, the drive transmission belt 22b, and the crankshaft pulley 22. That is, the waste heat of the engine 2 is recovered as the rotational driving force of the crankshaft 21.

  The steam that has become a low pressure through the turbine 34 may be about 60 ° C. (which is considerably lower than the upper limit temperature of the cooling water in the radiator 32). Therefore, the low-pressure steam is condensed by being cooled by the engine coolant condenser 35a, which can be lower in temperature than the radiator 32, and becomes liquid. Thereafter, the liquid cooling water is collected in the catch tank 36.

<< immediately after engine stop >>
Even after the engine 2 is stopped, the drive of the electric pump 37 is appropriately continued while the system 1 is activated. By driving the electric pump 37, the liquid coolant is circulated and the steam is continuously introduced into the engine coolant condenser 35a by the negative pressure.

  Here, in the present embodiment, the cooling system of the electric motor system 6 including the hybrid radiator 35b and the electric pump 37 are driven even after the engine 2 is stopped.

  Thereby, the steam inside the engine 2 and the coolant circulation path 4 is introduced into the engine coolant condenser 35a, and the engine coolant condenser 35a is continuously cooled by the hybrid radiator 35b and the like. Therefore, the cooling water condensing performance in the engine cooling water condenser 35a while the engine 2 is stopped is ensured satisfactorily.

<< When engine temperature is high >>
During the start of the engine 2 and during a high load operation, the temperature of the engine 2 may exceed the above upper limit value. In this case, the bypass switching valve 38 is switched from the above state. That is, the communication between the upstream side and the downstream side of the bypass switching valve 38 in the steam outlet passage 42 is blocked, and the upstream side of the bypass passage 47 and the upstream side of the bypass switching valve 38 in the steam outlet passage 42 is communicated.

  In this state, a large amount of liquid cooling water is circulated. Thereby, the engine 2 is cooled well and overheating is avoided.

<Operation / Effects of Configuration of Embodiment>
As described above, in the configuration of the present embodiment, the cooling water condensing performance in the engine cooling water condenser 35a is ensured even after the engine 2 is stopped.

  As a result, when the engine 2 is restarted, a sufficient amount of liquid cooling water can be secured in the catch tank 36 for restarting the engine waste heat recovery system 1 (energy recovery mechanism 3). . Therefore, the system 1 (energy recovery mechanism 3) can be quickly operated when the engine 2 is restarted.

  Further, in the configuration of the present embodiment, a part of the multifunction capacitor 35 that is normally provided in the hybrid vehicle can be used as a capacitor in a so-called Rankine cycle. That is, the capacitor in the Rankine cycle can be integrated with the multifunction capacitor 35 that is normally provided in the hybrid vehicle.

  Therefore, good mountability on the vehicle is realized. In addition, the Rankine cycle system can be improved in the hybrid vehicle without reducing the cooling performance and air conditioning performance of the electric motor system 6 only by changing a part of the structure of the multi-function capacitor 35 normally provided in the hybrid vehicle. Can be installed.

<Second embodiment>
FIG. 2 is a schematic configuration diagram of the system 1 according to the second embodiment of the present invention. In the description of the present embodiment, members having the same configuration and function as those described in the first embodiment are denoted by the same reference numerals as in FIG. To do. In addition, the description in the first embodiment described above can be used within a technically consistent range.

  In the present embodiment, a cooling water amount sensor 51 is attached to the catch tank 36. The cooling water amount sensor 51 is electrically connected to the electronic control unit 5.

  The cooling water amount sensor 51 as the working fluid amount output unit of the present invention is configured to generate an output corresponding to the amount of liquid cooling water that can be supplied to the engine 2 (stored in the catch tank 36). . Specifically, in the present embodiment, the cooling water amount sensor 51 is configured to generate an output corresponding to whether or not the amount of cooling water stored in the catch tank 36 is less than a predetermined amount.

  The electronic control unit 5 as a control unit of the present invention controls the condensing operation state in the engine cooling water condenser 35 a when the engine 2 is stopped according to the output of the cooling water amount sensor 51. Specifically, the electronic control unit 5 controls the operating state of the cooling system of the electric motor system 6 including the hybrid radiator 35 b and the electric pump 37 when the engine 2 is stopped according to the output of the cooling water amount sensor 51. It is configured as follows.

  In such a configuration, when it is determined that the amount of coolant stored in the catch tank 36 is less than a predetermined amount, the condensing operation in the engine coolant condenser 35a is continued even when the engine 2 is stopped. Each unit is driven as described above.

  On the other hand, when it is determined that a predetermined amount of cooling water is stored in the catch tank 36, the drive of the electric pump 37 is stopped while the engine 2 is stopped. In this case, if the temperature of the electric motor system 6 is low, the cooling system of the electric motor system 6 including the hybrid radiator 35b is also stopped.

  According to the present embodiment, the condensing operation in the engine coolant condenser 35a while the engine 2 is stopped is continued only when the amount of coolant stored in the catch tank 36 is insufficient. Therefore, a better fuel economy reduction effect can be obtained.

<List of examples of modification>
Note that, as described above, the above-described embodiments are merely examples of typical embodiments of the present invention that the applicant has considered to be the best at the time of filing of the present application. Therefore, the present invention is not limited to the above-described embodiment. Therefore, it goes without saying that various modifications can be made to the above-described embodiment within the scope not changing the essential part of the present invention.

  Hereinafter, some typical modifications will be exemplified. However, it goes without saying that the modifications are not limited to those listed below. In addition, a plurality of modified examples can be applied in a composite manner as appropriate within a technically consistent range. The present invention should not be limitedly interpreted based on the description of the above-described embodiment and the following modified examples.

  (A) The present invention is not limited to application to a hybrid vehicle. That is, the hybrid radiator 35b can be omitted. In this case, the air conditioner condenser 35c can cool the engine coolant condenser 35a when the engine 2 is stopped.

  (B) The configurations of the energy recovery mechanism 3 and the cooling water circulation path 4 can be appropriately changed from those disclosed in the above-described embodiment.

  For example, the energy recovered by the turbine 34 may be converted into electricity. Moreover, as an energy recovery part, it replaces with the turbine 34 and the mechanism provided with the piston may be used.

  The radiator 32 and the catch tank 36 may not be connected to each other.

  The electric pump 37 may be provided separately from the engine 2. Alternatively, instead of the electric pump 37, a mechanical pump and a clutch mechanism (a mechanism that switches transmission of driving force between the mechanical pump and the crankshaft 21) may be used. In addition to the electric pump 37, a pump for circulating liquid cooling water between the engine 2 and the radiator 32 may be provided.

  As the working fluid in the energy recovery mechanism 3 of the system 1, a fluid other than the engine cooling water can be used. In this case, the system 1 is provided with a working fluid circulation path in addition to the cooling water circulation path 4, and the main parts of the energy recovery mechanism 3 (superheater, energy recovery part, working fluid condenser, cooling, etc.) Etc.).

  The cooling water amount sensor 51 may be provided at a place other than the catch tank 36 (for example, a position between the engine cooling water condenser 35a and the catch tank 36 in the cooling water supply path 41).

  (C) In addition, in the elements constituting the means for solving the problems of the present invention, the elements that are expressed functionally and functionally are the specific structures disclosed in the above-described embodiments and modifications. In addition, any structure capable of realizing the operation / function is included.

1 is a schematic configuration diagram of an engine waste heat recovery system according to a first embodiment of the present invention. It is a schematic block diagram of the engine waste heat recovery system which concerns on 2nd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine waste heat recovery system 2 ... Engine 21 ... Crankshaft 22 ... Crankshaft pulley 22b ... Drive transmission belt 23 ... Exhaust pipe 24 ... Temperature sensor 3 ... Energy recovery mechanism 31 ... Gas-liquid separator 32 ... Radiator 33 ... Superheater 34 ... Turbine 34a ... Turbine pulley 35 ... Multi-function condenser 35a ... Engine cooling water condenser 35b ... Hybrid radiator 35c ... Air conditioning condenser 36 ... Catch tank 37 ... Electric pump 38 ... Bypass switching valve 4 ... Cooling water circulation path 41 ... Cooling water supply Path 42 ... Steam outlet path 43 ... Separation cooling water outlet path 44 ... Hot water outlet path 45 ... Cold water supply path 46 ... Turbine outlet path 47 ... Bypass path 48 ... Tank connection path 5 ... Electronic control unit 51 ... Cooling water amount Capacitors 6 ... motor system

Claims (6)

In the engine waste heat recovery system configured to recover the energy of the steam of the working fluid heated by the waste heat of the engine by the energy recovery unit,
A working fluid condenser that condenses the vapor that has passed through the energy recovery unit;
A cooler capable of cooling the working fluid condenser when the engine is stopped;
An engine waste heat recovery system characterized by comprising: The engine waste heat recovery system according to claim 1,
An engine waste heat recovery system, wherein the cooler includes an air conditioning system condenser that condenses an air conditioning system refrigerant that is a refrigerant of an air conditioning system in a vehicle. The engine waste heat recovery system according to claim 1 or 2,
2. The engine waste heat recovery system according to claim 1, wherein the cooler includes an electric motor refrigerant cooling unit that cools an electric motor refrigerant that is a refrigerant of the electric motor system in the hybrid vehicle. The engine waste heat recovery system according to any one of claims 1 to 3,
A working fluid amount output section for generating an output corresponding to the amount of the liquid working fluid that can be supplied to the engine;
A control unit for controlling a condensing operation state in the working fluid condenser when the engine is stopped according to an output of the working fluid amount output unit;
An engine waste heat recovery system characterized by comprising: The engine waste heat recovery system according to claim 4,
An electric pump interposed in the working fluid circulation path;
The engine waste heat recovery system, wherein the control unit controls an operating state of the electric pump when the engine is stopped according to an output of the working fluid amount output unit. In the engine waste heat recovery system according to claim 4 or 5,
A working fluid tank that is interposed in the circulation path downstream of the working fluid condenser in the flow direction of the working fluid and can store the liquid working fluid;
The engine waste heat recovery system, wherein the working fluid amount output unit is attached to the working fluid tank.

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