US20190048749A1 - Waste heat recovery system - Google Patents
Waste heat recovery system Download PDFInfo
- Publication number
- US20190048749A1 US20190048749A1 US16/087,715 US201616087715A US2019048749A1 US 20190048749 A1 US20190048749 A1 US 20190048749A1 US 201616087715 A US201616087715 A US 201616087715A US 2019048749 A1 US2019048749 A1 US 2019048749A1
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- US
- United States
- Prior art keywords
- slide
- expansion machine
- fluid outlet
- recovery system
- heat recovery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000011084 recovery Methods 0.000 title claims abstract description 29
- 239000002918 waste heat Substances 0.000 title claims abstract description 29
- 239000012530 fluid Substances 0.000 claims abstract description 130
- 239000007789 gas Substances 0.000 claims abstract description 28
- 238000002485 combustion reaction Methods 0.000 claims abstract description 24
- 238000007789 sealing Methods 0.000 claims description 4
- 239000002826 coolant Substances 0.000 description 9
- 238000001816 cooling Methods 0.000 description 9
- 239000000470 constituent Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/065—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy
- F01N5/02—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy the devices using heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
- F02G5/02—Profiting from waste heat of exhaust gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
- F16K3/22—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution
- F16K3/24—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution with cylindrical valve members
- F16K3/26—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution with cylindrical valve members with fluid passages in the valve member
- F16K3/267—Combination of a sliding valve and a lift valve
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0603—Multiple-way valves
- F16K31/061—Sliding valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0603—Multiple-way valves
- F16K31/0624—Lift valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2220/00—Application
- F05D2220/40—Application in turbochargers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Definitions
- the invention relates to a waste-heat recovery system with a working fluid circuit having a heat exchanger connected into an exhaust-gas line of the internal combustion engine, wherein the heat exchanger is part of the working fluid circuit with at least one expansion machine which has a bypass controlled by a valve.
- a waste-heat recovery system of said type is known from DE 10 2013 021 251 A1.
- Said waste-heat recovery system has a working fluid circuit which has the conventional components. These are, substantially, an evaporator connected into an exhaust-gas line of an internal combustion engine, and expansion machine with the bypass control by a valve, a condenser, and a working fluid pump. By means of the bypass control by the valve, the expansion machine can be switched into a torque-free state.
- the bypass and the valve are arranged within or integrated into the expansion machine.
- the invention is based on the object of providing a waste-heat recovery system which is improved with regard to its function.
- valve is a directional valve, in particular 3/2 directional valve, which connects a fluid inlet to an expansion machine fluid outlet and/or to a bypass fluid outlet, and in that a connection made between fluid inlet and expansion machine fluid outlet exhibits no leakage to the bypass fluid outlet.
- 3/2 directional valve can conduct the working fluid flowing and the working fluid circuit either via the expansion machine or, pass the expansion machine, directly to a condenser provided in the working fluid circuit downstream of the expansion machine.
- a connection made between fluid inlet and bypass fluid outlet exhibits leakage, with a leakage quantity, to the expansion machine fluid outlet.
- the leakage quantity to the expansion machine fluid outlet is less than 10% of the maximum volume flow of the working fluid through the working fluid circuit, preferably less than 1% of the maximum volume flow.
- Such a minimum leakage quantity is expedient because, in this way, the expansion machine is for example heated during a commencement of operation of the waste-heat recovery system, or in the event of temporary bypassing the expansion machine, cooling of the expansion machine is prevented. “Permanent lubrication” of the expansion machine is also ensured. This embodiment also sustainably improves the function of the waste-heat recovery system.
- the 3/2 directional valve has a slide (in the form of a piston) with two opposite switching positions that can be assumed by the slide.
- the switching positions of the slide can be defined or occupied by a slide seat on the bypass fluid outlet and an expansion machine outlet seat at the expansion machine fluid outlet.
- the switching positions of the slide may be defined by a slide seat on the bypass fluid outlet and, as a substitute for the single expansion machine outlet seat at the expansion machine fluid outlet, by an overlap gap assumed by the slide relative to a slide housing.
- This embodiment is basically similar in terms of function to the first embodiment, wherein here, the required stroke of the slide is longer owing to the overlap that is to be realized.
- the 3/2 directional valve has a slide housing and a slide which is displaceable in said slide housing axially counter to the force of a spring, which slide has a permanent flow connection to the fluid inlet and can be adjusted in each case into a flow connection with the bypass fluid outlet and with the expansion machine fluid outlet.
- the bypass fluid outlet has a bypass fluid outlet seat into which an end-side slide seat of the slide can be engaged with sealing action. In this way, in a corresponding switching position of the slide, the absence of leakage of the fluid inlet to the bypass fluid outlet is ensured.
- the slide seat is arranged on a slide base wall of the slide of piston-like form (opposite the side of the connection of an actuator switching rod), and wherein the slide base wall has at least one passage opening which permits a throttling-free throughflow of the working fluid.
- the desired leakage of the working fluid to the expansion machine outlet may be produced or set by means of corresponding play between the slide and the slide housing.
- the leakage may however also be produced by means of a leakage throttle bore in the slide.
- the slide interacts with an actuator.
- the actuator may be designed as an electromagnet or else may be configured or actuated in pneumatic, hydraulic or electromagnetic or some other form.
- waste-heat recovery system configured in this way offers the following advantages:
- FIG. 1 shows a schematic circuit diagram of a waste-heat recovery system which has an expansion machine and a working fluid circuit, wherein the waste-heat recovery system is installed on an internal combustion engine,
- FIG. 2 a shows a first exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a first switching position
- FIG. 2 b shows a first exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a second switching position
- FIG. 3 a shows a second exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a first switching position
- FIG. 3 b shows a second exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a second switching position.
- FIG. 1 shows a waste-heat recovery system 1 , which is installed on an internal combustion engine 2 which has a cooling system (not illustrated in any more detail).
- the internal combustion engine 2 furthermore has a fresh-gas line 3 and an exhaust-gas line 4 .
- the internal combustion engine 2 is supplied with combustion air which, in the exemplary embodiment, is compressed by a compressor 5 of an exhaust-gas turbocharger 6 , which in turn is driven by a turbine 7 incorporated into the exhaust-gas line 4 .
- a charge-air cooler 8 and a throttle flap 9 are connected downstream of the compressor 6 .
- fuel for example diesel fuel
- the exhaust-gas line 4 is connected to the fresh-gas line 3 via an exhaust-gas recirculation line 12 with, incorporated therein, an exhaust-gas recirculation cooler 13 and an exhaust-gas recirculation valve 14 .
- exhaust gas is recirculated in controlled fashion into the fresh-gas line 3 , in particular in order to reduce the harmful exhaust-gas emissions.
- an exhaust-gas aftertreatment device 15 is likewise provided for reducing the harmful exhaust-gas emissions.
- a heat exchanger in the form of a superheater 16 of the waste-heat recovery system 1 is incorporated into the exhaust-gas line 4 , which heat exchanger can be bypassed in controlled fashion via an exhaust-gas line bypass 17 .
- the superheater 16 is incorporated into a working fluid circuit 18 of the waste-heat recovery system 1 —as will be discussed in more detail below.
- the internal combustion engine 2 has the abovementioned cooling system with a coolant circuit, which is however of no further importance of the subject matter of the invention and is therefore not illustrated.
- the cooling system serves for the cooling of the internal combustion engine 2 and has a coolant cooler incorporated into the cooling circuit and a coolant pump.
- the coolant pump conveys the coolant through cooling chambers of the internal combustion engine 2 into the coolant cooler, which is connected at the outlet side to the suction side of the coolant pump.
- Also suitably incorporated into said coolant circuit are, for example, a lubricating oil heat exchanger, a retarder heat exchanger, the charge-air cooler 8 and the exhaust-gas recirculation cooler 13 .
- the latter has the working fluid circuit 18 with the superheater 16 incorporated into the exhaust-gas line 4 .
- an expansion machine 20 which is driven by the working fluid changed into the gaseous state in the superheater 16 , with expansion of said fluid, and which outputs working power to the internal combustion engine 2 or to some other machine, for example a generator.
- the expansion machine 20 can be bypassed via a working fluid bypass 21 , which is controlled by a directional valve 22 formed preferably as a 3/2 directional valve.
- a condenser 23 is incorporated into the working fluid circuit 18 downstream of the expansion machine 20 , in which condenser the working fluid is normally cooled down into the liquid state and is subsequently supplied to a working fluid pump 24 .
- the working fluid pump 24 is for example electrically driven by a motor 19 and conveys the cooled-down working fluid back to the superheater 16 .
- a pressure compensation tank 25 is incorporated into the working fluid circuit 18 .
- the abovementioned condenser 23 is in turn a constituent part of a working fluid cooling circuit 26 , which furthermore has a cooler 27 .
- the cooler 27 is for example arranged upstream or downstream of the coolant cooler and is flowed through by a cooling air flow which is conveyed for example by a fan 28 , which is driven directly or indirectly by the internal combustion engine 2 .
- an electric or electronic control device 29 is provided, which controls the waste-heat recovery system 1 including possibly the entire internal combustion engine 2 .
- Said control device 29 also serves for controlling the 3/2 directional valve 22 of the waste-heat recovery system 1 , which valve will be discussed in more detail with regard to its design and function in the following figures.
- FIG. 2 a shows the directly controlled 2/3 directional valve 22 , which is pressure-balanced at least in one switching position, in a first embodiment, and shows a switching position in which the working fluid of the working fluid circuit 18 is conducted to the expansion machine 20 .
- the working fluid is conducted to the working fluid bypass 21 and thus so as to bypass the expansion machine 20 .
- the 3/2 directional valve 22 has a cylindrical tubular slide housing 30 in which a slide 31 of piston-like form is adjustable axially counter to the force of a spring 32 .
- Said adjustment movement is effected by an actuator 33 which is fixedly connected by means of an actuator holding device 34 to the slide housing 30 and which has an actuator switching rod 35 , which in turn is connected to the slide 31 for the direct axial adjustment of the slide 31 .
- the actuator 33 is formed as an electromagnet and, when electrically energized, moves the actuator switching rod 35 with the slide 31 into the position illustrated in FIG. 2 a , whereas, when electrically deenergized, the position of the slide 31 illustrated in FIG. 2 b is set by means of the restoring force of the spring 32 .
- the actuator 33 may however also for example be of pneumatic, hydraulic or electromagnetic form in other embodiments.
- the slide housing 30 has a tubular and flange-mounted fluid inlet 36 , which is connected to the working fluid circuit 18 at the outlet side of the superheater 16 . Furthermore, the slide housing 30 has a likewise tubular expansion machine fluid outlet 37 , which is connected directly or indirectly to the flow inlet into the expansion machine 20 .
- the expansion machine fluid outlet 37 may, like the fluid inlet 36 , be configured as a metallic pipe connection piece, which is welded to the slide housing 30 , the latter likewise being manufactured from a metallic material.
- the 3/2 directional valve 22 has a bypass fluid outlet 38 , which is connected to the working fluid bypass 21 .
- the bypass fluid outlet 38 is arranged on a closure plate 39 , opposite the actuator holding device 34 , on the slide housing 30 , or is a constituent part of the closure plate 39 and formed for example as a bypass fluid outlet pipe with a throttling action set by means of the pipe diameter.
- the bypass fluid outlet 38 or the bypass fluid outlet pipe has a bypass fluid outlet seat 40 , in which an end-side facing slide seat 41 of the slide 31 can be engaged with sealing action and thus in leakage-free fashion.
- the slide seat 41 is arranged on, or formed in one piece with, a slide base wall of the slide 31 of piston-like form, wherein the slide base wall has passage openings 45 for an unhindered throughflow of the working fluid.
- FIG. 2 a The corresponding switching position is illustrated in FIG. 2 a .
- the working fluid flowing into the 3/2 directional valve 22 or the slide housing 30 via the fluid inlet 36 flows in leakage-free fashion into the expansion machine fluid outlet 37 in accordance with the illustrated flow arrows.
- an encircling ring-shaped groove 42 is recessed into the slide housing 30 , which ring-shaped groove promotes an unhindered flow through the 3/2 directional valve 22 and, at the same time, in the direction of the actuator holding device 34 , transitions into an expansion machine fluid outlet seat 43 adjacent to the fluid inlet 36 .
- the slide 31 is displaceable with an encircling slide edge 44 into the expansion machine fluid outlet seat 43 , which is formed for example by a cylindrical pipe diameter reduction of the slide housing 30 .
- the corresponding switching position is, as stated above, illustrated in FIG. 2 b .
- the direct passage from the fluid inlet 36 via the expansion machine outlet seat 43 and the ring-shaped groove 42 into the expansion machine outlet 37 is blocked.
- the working fluid flows, in accordance with the illustrated flow arrows, through the slide 31 of piston-like form, and passes via the passage openings 45 directly into the bypass fluid outlet 38 , because, in this switching position, the slide seat 41 has been moved out of the bypass fluid outlet seat 40 and opens up a flow connection.
- a small leakage of the maximum volume flow of the working fluid from the fluid inlet 36 to the expansion machine fluid outlet 37 is set, which is set by means of the play with which the slide 31 is guided in the slide housing 30 .
- the defined leakage quantity 46 a of the working fluid passes from the slide seat 41 back to the expansion machine fluid outlet 37 .
- at least one leakage throttle bore 47 a illustrated only in FIG. 2 b , to be provided in the slide 31 in the region of the ring-shaped groove 42 .
- the leakage quantity 46 a of the working fluid is less than 10% of the maximum volume flow, preferably less than 1% of the maximum volume flow.
- the exemplary embodiment as per FIGS. 3 a , 3 b differs from that of FIGS. 2 a , 2 b in that, here, no expansion machine fluid outlet seat 43 is provided into which a slide edge 44 could engage in the switching position as per FIG. 3 b .
- the slide housing 30 is formed with a shoulder-free internal diameter.
- the entire leakage quantity 46 a , 46 b of the working fluid is less than 10% of the maximum volume flow, preferably less than 1% of the maximum volume flow. Furthermore, in this embodiment, the switching travel to be covered by the actuator 33 is longer than in the exemplary embodiment as per FIGS. 2 a , 2 b .
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Engine Equipment That Uses Special Cycles (AREA)
Abstract
The invention relates to a waste heat recovery system (1) comprising a working fluid circuit (18), having a heat exchanger which is connected in an exhaust gas line (4) of an internal combustion engine (2). The heat exchanger is part of the working fluid circuit (18) together with an expansion machine (20) which has at least one working fluid bypass (21) that is controlled by a valve. According to the invention, a waste heat recovery system (1) is provided with improved functionality. This is achieved in that the valve is a directional valve which connects a fluid inlet (36) to an expansion machine fluid outlet (37) and/or a bypass fluid outlet (38), in particular a 3/2-way valve (22), and the connection of the fluid inlet (36) to the expansion machine fluid outlet (37) is leakage-free relative to the bypass fluid outlet (38), whereas the connection of the fluid inlet (36) to the bypass fluid outlet (38) exhibits leakages with respect to the expansion machine fluid outlet (37).
Description
- The invention relates to a waste-heat recovery system with a working fluid circuit having a heat exchanger connected into an exhaust-gas line of the internal combustion engine, wherein the heat exchanger is part of the working fluid circuit with at least one expansion machine which has a bypass controlled by a valve.
- A waste-heat recovery system of said type is known from DE 10 2013 021 251 A1. Said waste-heat recovery system has a working fluid circuit which has the conventional components. These are, substantially, an evaporator connected into an exhaust-gas line of an internal combustion engine, and expansion machine with the bypass control by a valve, a condenser, and a working fluid pump. By means of the bypass control by the valve, the expansion machine can be switched into a torque-free state. Here, the bypass and the valve are arranged within or integrated into the expansion machine.
- The invention is based on the object of providing a waste-heat recovery system which is improved with regard to its function.
- Said object is achieved in that the valve is a directional valve, in particular 3/2 directional valve, which connects a fluid inlet to an expansion machine fluid outlet and/or to a bypass fluid outlet, and in that a connection made between fluid inlet and expansion machine fluid outlet exhibits no leakage to the bypass fluid outlet. Said 3/2 directional valve can conduct the working fluid flowing and the working fluid circuit either via the expansion machine or, pass the expansion machine, directly to a condenser provided in the working fluid circuit downstream of the expansion machine. It is a first object of said 3/2 directional valve, for example in the case of a mechanical connection of the expansion machine to a crankshaft of the internal combustion engine, and in the presence of a torque demand of “zero”, to conduct the working fluid directly to the condenser, such that the expansion machine is not driven by the working fluid and therefore outputs no torque to the crankshaft. It is a second object of the 3/2 directional valve to protect the expansion machine if the working fluid is in a wet steam range. During expander operation, in which the expansion machine is flowed through in the intended manner by the working fluid, leakage in the direction of the bypass, which would constitute an impairment of the efficiency of the expansion machine, is prevented according to the invention. By means of this embodiment, the function of the waste-heat recovery system is improved.
- In a refinement of the invention, a connection made between fluid inlet and bypass fluid outlet exhibits leakage, with a leakage quantity, to the expansion machine fluid outlet. Here, in a further embodiment of the invention, the leakage quantity to the expansion machine fluid outlet is less than 10% of the maximum volume flow of the working fluid through the working fluid circuit, preferably less than 1% of the maximum volume flow. Such a minimum leakage quantity is expedient because, in this way, the expansion machine is for example heated during a commencement of operation of the waste-heat recovery system, or in the event of temporary bypassing the expansion machine, cooling of the expansion machine is prevented. “Permanent lubrication” of the expansion machine is also ensured. This embodiment also sustainably improves the function of the waste-heat recovery system.
- In a refinement of the invention, the 3/2 directional valve has a slide (in the form of a piston) with two opposite switching positions that can be assumed by the slide. Here, the switching positions of the slide can be defined or occupied by a slide seat on the bypass fluid outlet and an expansion machine outlet seat at the expansion machine fluid outlet. This is one possible embodiment, in which a short stroke of the slide can be realized, whereby, in turn, a simple, inexpensive design of an actuating element for the adjustment of the slide can be realized.
- In a second embodiment, the switching positions of the slide may be defined by a slide seat on the bypass fluid outlet and, as a substitute for the single expansion machine outlet seat at the expansion machine fluid outlet, by an overlap gap assumed by the slide relative to a slide housing. This embodiment is basically similar in terms of function to the first embodiment, wherein here, the required stroke of the slide is longer owing to the overlap that is to be realized.
- In a further configuration of the invention, the 3/2 directional valve has a slide housing and a slide which is displaceable in said slide housing axially counter to the force of a spring, which slide has a permanent flow connection to the fluid inlet and can be adjusted in each case into a flow connection with the bypass fluid outlet and with the expansion machine fluid outlet. This is an embodiment of the 3/2 directional valve realized in all conceivable configurations.
- In a refinement of the invention, the bypass fluid outlet has a bypass fluid outlet seat into which an end-side slide seat of the slide can be engaged with sealing action. In this way, in a corresponding switching position of the slide, the absence of leakage of the fluid inlet to the bypass fluid outlet is ensured.
- In a refinement of the invention, the slide seat is arranged on a slide base wall of the slide of piston-like form (opposite the side of the connection of an actuator switching rod), and wherein the slide base wall has at least one passage opening which permits a throttling-free throughflow of the working fluid.
- The desired leakage of the working fluid to the expansion machine outlet may be produced or set by means of corresponding play between the slide and the slide housing. Alternatively, the leakage may however also be produced by means of a leakage throttle bore in the slide.
- In a further configuration of the invention, the slide interacts with an actuator. The actuator may be designed as an electromagnet or else may be configured or actuated in pneumatic, hydraulic or electromagnetic or some other form.
- In summary, the waste-heat recovery system configured in this way offers the following advantages:
-
- in turbine operation, in which the working fluid is to be conducted entirely through the expansion machine, it is ensured that no leakage occurs in the direction of the bypass fluid outlet,
- by contrast, in bypass operation, when the working fluid is conducted through the bypass, a minimal leakage in the direction of the expansion machine fluid outlet is set in order, for example, to heat the expansion machine,
- only low actuator forces are necessary, because the slide is pressure-balanced. The actuator consequently has to overcome only spring forces and flow forces,
- in expander operation, it is likewise the case that only low actuator forces are necessary, because, in this switching state, the slide is not force-balanced, and the acting force acts with a closing action toward the bypass fluid outlet,
- a robust design with low acting seat forces can be implemented, and
- the 3/2 directional valve can be implemented inexpensively.
- Further advantageous configurations of the invention emerge from the description of the drawings, which gives a description of exemplary embodiments illustrated in the figures.
- In the figures:
-
FIG. 1 shows a schematic circuit diagram of a waste-heat recovery system which has an expansion machine and a working fluid circuit, wherein the waste-heat recovery system is installed on an internal combustion engine, -
FIG. 2a shows a first exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a first switching position, -
FIG. 2b shows a first exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a second switching position, -
FIG. 3a shows a second exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a first switching position, -
FIG. 3b shows a second exemplary embodiment of a bypass, controlled by a valve, of the working fluid circuit past an expansion machine in a second switching position. -
FIG. 1 shows a waste-heat recovery system 1, which is installed on an internal combustion engine 2 which has a cooling system (not illustrated in any more detail). The internal combustion engine 2 furthermore has a fresh-gas line 3 and an exhaust-gas line 4. Via the fresh-gas line 3, the internal combustion engine 2 is supplied with combustion air which, in the exemplary embodiment, is compressed by a compressor 5 of an exhaust-gas turbocharger 6, which in turn is driven by a turbine 7 incorporated into the exhaust-gas line 4. A charge-air cooler 8 and a throttle flap 9 are connected downstream of thecompressor 6. - The fresh gas supplied to individual combustion chambers of the internal combustion engine 2 with a simultaneous supply of fuel, for example diesel fuel, burns in the combustion chambers of the internal combustion engine 2, generating working power, which is output, for example via an
output shaft 10 which is connected to the crankshaft of the internal combustion engine 2 via a transmission, to adrive axle 11, by means of which an arbitrary vehicle in which the internal combustion engine 2 is installed is driven. Via the exhaust-gas line 4, the mixture of fuel and fresh gas burned in the combustion chambers of the internal combustion engine 2 is ultimately discharged as hot gas into the surroundings. The exhaust-gas line 4 is connected to the fresh-gas line 3 via an exhaust-gas recirculation line 12 with, incorporated therein, an exhaust-gas recirculation cooler 13 and an exhaust-gas recirculation valve 14. Via the exhaust-gas recirculation line 12, exhaust gas is recirculated in controlled fashion into the fresh-gas line 3, in particular in order to reduce the harmful exhaust-gas emissions. Downstream of the turbine 7, an exhaust-gas aftertreatment device 15 is likewise provided for reducing the harmful exhaust-gas emissions. Further downstream, a heat exchanger in the form of asuperheater 16 of the waste-heat recovery system 1 is incorporated into the exhaust-gas line 4, which heat exchanger can be bypassed in controlled fashion via an exhaust-gas line bypass 17. Thesuperheater 16 is incorporated into a workingfluid circuit 18 of the waste-heat recovery system 1—as will be discussed in more detail below. - The internal combustion engine 2 has the abovementioned cooling system with a coolant circuit, which is however of no further importance of the subject matter of the invention and is therefore not illustrated. The cooling system serves for the cooling of the internal combustion engine 2 and has a coolant cooler incorporated into the cooling circuit and a coolant pump. The coolant pump conveys the coolant through cooling chambers of the internal combustion engine 2 into the coolant cooler, which is connected at the outlet side to the suction side of the coolant pump. Also suitably incorporated into said coolant circuit are, for example, a lubricating oil heat exchanger, a retarder heat exchanger, the charge-air cooler 8 and the exhaust-
gas recirculation cooler 13. - Returning to the waste-heat recovery system 1, the latter has the working
fluid circuit 18 with thesuperheater 16 incorporated into the exhaust-gas line 4. Also incorporated into the workingfluid circuit 18 is anexpansion machine 20 which is driven by the working fluid changed into the gaseous state in thesuperheater 16, with expansion of said fluid, and which outputs working power to the internal combustion engine 2 or to some other machine, for example a generator. Here, theexpansion machine 20 can be bypassed via a workingfluid bypass 21, which is controlled by adirectional valve 22 formed preferably as a 3/2 directional valve. Furthermore, acondenser 23 is incorporated into the workingfluid circuit 18 downstream of theexpansion machine 20, in which condenser the working fluid is normally cooled down into the liquid state and is subsequently supplied to a workingfluid pump 24. The workingfluid pump 24 is for example electrically driven by amotor 19 and conveys the cooled-down working fluid back to thesuperheater 16. Here, at the outlet side of the workingfluid pump 24, apressure compensation tank 25 is incorporated into the workingfluid circuit 18. - The
abovementioned condenser 23 is in turn a constituent part of a workingfluid cooling circuit 26, which furthermore has a cooler 27. The cooler 27 is for example arranged upstream or downstream of the coolant cooler and is flowed through by a cooling air flow which is conveyed for example by afan 28, which is driven directly or indirectly by the internal combustion engine 2. Finally, an electric or electronic control device 29 is provided, which controls the waste-heat recovery system 1 including possibly the entire internal combustion engine 2. Said control device 29 also serves for controlling the 3/2directional valve 22 of the waste-heat recovery system 1, which valve will be discussed in more detail with regard to its design and function in the following figures. -
FIG. 2a shows the directly controlled 2/3directional valve 22, which is pressure-balanced at least in one switching position, in a first embodiment, and shows a switching position in which the working fluid of the workingfluid circuit 18 is conducted to theexpansion machine 20. By contrast, in the switching position of the 3/2directional valve 22 illustrated inFIG. 2b , the working fluid is conducted to the workingfluid bypass 21 and thus so as to bypass theexpansion machine 20. The 3/2directional valve 22 has a cylindricaltubular slide housing 30 in which a slide 31 of piston-like form is adjustable axially counter to the force of aspring 32. Said adjustment movement is effected by anactuator 33 which is fixedly connected by means of anactuator holding device 34 to theslide housing 30 and which has anactuator switching rod 35, which in turn is connected to the slide 31 for the direct axial adjustment of the slide 31. For example, theactuator 33 is formed as an electromagnet and, when electrically energized, moves theactuator switching rod 35 with the slide 31 into the position illustrated inFIG. 2a , whereas, when electrically deenergized, the position of the slide 31 illustrated inFIG. 2b is set by means of the restoring force of thespring 32. Theactuator 33 may however also for example be of pneumatic, hydraulic or electromagnetic form in other embodiments. - The
slide housing 30 has a tubular and flange-mountedfluid inlet 36, which is connected to the workingfluid circuit 18 at the outlet side of thesuperheater 16. Furthermore, theslide housing 30 has a likewise tubular expansionmachine fluid outlet 37, which is connected directly or indirectly to the flow inlet into theexpansion machine 20. The expansionmachine fluid outlet 37 may, like thefluid inlet 36, be configured as a metallic pipe connection piece, which is welded to theslide housing 30, the latter likewise being manufactured from a metallic material. Furthermore, the 3/2directional valve 22 has abypass fluid outlet 38, which is connected to the workingfluid bypass 21. Thebypass fluid outlet 38 is arranged on aclosure plate 39, opposite theactuator holding device 34, on theslide housing 30, or is a constituent part of theclosure plate 39 and formed for example as a bypass fluid outlet pipe with a throttling action set by means of the pipe diameter. - The
bypass fluid outlet 38 or the bypass fluid outlet pipe has a bypassfluid outlet seat 40, in which an end-side facingslide seat 41 of the slide 31 can be engaged with sealing action and thus in leakage-free fashion. Theslide seat 41 is arranged on, or formed in one piece with, a slide base wall of the slide 31 of piston-like form, wherein the slide base wall haspassage openings 45 for an unhindered throughflow of the working fluid. - The corresponding switching position is illustrated in
FIG. 2a . In this switching position, the working fluid flowing into the 3/2directional valve 22 or theslide housing 30 via thefluid inlet 36 flows in leakage-free fashion into the expansionmachine fluid outlet 37 in accordance with the illustrated flow arrows. In the region of the expansionmachine fluid outlet 37, an encircling ring-shapedgroove 42 is recessed into theslide housing 30, which ring-shaped groove promotes an unhindered flow through the 3/2directional valve 22 and, at the same time, in the direction of theactuator holding device 34, transitions into an expansion machinefluid outlet seat 43 adjacent to thefluid inlet 36. - The slide 31 is displaceable with an
encircling slide edge 44 into the expansion machinefluid outlet seat 43, which is formed for example by a cylindrical pipe diameter reduction of theslide housing 30. The corresponding switching position is, as stated above, illustrated inFIG. 2b . In this switching position, the direct passage from thefluid inlet 36 via the expansionmachine outlet seat 43 and the ring-shapedgroove 42 into theexpansion machine outlet 37 is blocked. At the same time, it is however the case that the working fluid flows, in accordance with the illustrated flow arrows, through the slide 31 of piston-like form, and passes via thepassage openings 45 directly into thebypass fluid outlet 38, because, in this switching position, theslide seat 41 has been moved out of the bypassfluid outlet seat 40 and opens up a flow connection. - At the same time, in this switching position, a small leakage of the maximum volume flow of the working fluid from the
fluid inlet 36 to the expansionmachine fluid outlet 37 is set, which is set by means of the play with which the slide 31 is guided in theslide housing 30. Here, the definedleakage quantity 46 a of the working fluid passes from theslide seat 41 back to the expansionmachine fluid outlet 37. Alternatively (in the case of play-free guidance of the slide 31 in the slide housing 30) or in addition, it is also possible for at least one leakage throttle bore 47 a, illustrated only inFIG. 2b , to be provided in the slide 31 in the region of the ring-shapedgroove 42. Theleakage quantity 46 a of the working fluid is less than 10% of the maximum volume flow, preferably less than 1% of the maximum volume flow. - The exemplary embodiment as per
FIGS. 3a, 3b differs from that ofFIGS. 2a, 2b in that, here, no expansion machinefluid outlet seat 43 is provided into which aslide edge 44 could engage in the switching position as perFIG. 3b . In this exemplary embodiment, theslide housing 30 is formed with a shoulder-free internal diameter. Thus, it is also the case in the switching position as perFIG. 3b (the switching position is identical to that ofFIG. 2a at least in terms of function) that aleakage quantity 46 b flows from said side from thefluid inlet 36 into the expansionmachine fluid outlet 37. In this embodiment, too, theentire leakage quantity actuator 33 is longer than in the exemplary embodiment as perFIGS. 2a, 2b . - It is finally pointed out that any design details illustrated in the figures may be combined with one another within the scope of the invention.
Claims (10)
1. A waste-heat recovery system (1) with a working fluid circuit (18) having a heat exchanger connected into an exhaust-gas line (4) of the internal combustion engine (2), wherein the heat exchanger is part of the working fluid circuit (18) with at least one expansion machine (20) which has a working fluid bypass (21) controlled by a valve, wherein the valve is a directional valve (22) which connects a fluid inlet (36) to an expansion machine fluid outlet (37) and/or to a bypass fluid outlet (38), and wherein a connection made between the fluid inlet (36) and the expansion machine fluid outlet (37) exhibits no leakage to the bypass fluid outlet (38).
2. The waste-heat recovery system (1) as claimed in claim 1 , characterized in that a connection made between fluid inlet (36) and the bypass fluid outlet (38) exhibits leakage, with a leakage quantity (46 a, 46 b), to the expansion machine fluid outlet (37).
3. The waste-heat recovery system (1) as claimed in claim 2 , characterized in that the leakage quantity (46 a, 46 b) is less than 10% of the maximum volume flow of the working fluid.
4. The waste-heat recovery system (1) as claimed in claim 2 , characterized in that the directional valve (22) has a slide (31) with two opposite switching positions that can be assumed by the slide (31).
5. The waste-heat recovery system (1) as claimed in claim 2 , characterized in that the directional valve (22) has a slide housing (30) and a slide (31) which is displaceable in said slide housing axially counter to the force of a spring (32), which slide has a permanent flow connection to the fluid inlet (36) and can be adjusted in each case into a flow connection with the bypass fluid outlet (38) and with the expansion machine fluid outlet (37).
6. The waste-heat recovery system (1) as claimed in claim 2 , characterized in that the directional valve (22) has a bypass fluid outlet seat (40) configured to have an end-side slide seat (41) of the slide (31) engaged therein with sealing action.
7. The waste-heat recovery system (1) as claimed in claim 2 , characterized in that the slide housing (30) has an expansion machine fluid outlet seat (43) configured to have a slide edge (44) of the slide (31) engaged therein with sealing action.
8. The waste-heat recovery system (1) as claimed in claim 6 , characterized in that the slide seat (41) is arranged on a slide base wall of the slide (31) of piston-like form, and in that the slide base wall has passage openings (45) for an unhindered throughflow of the working fluid.
9. The waste-heat recovery system (1) as claimed in claim 4 , characterized in that the slide (31) interacts with an actuator (33).
10. The waste-heat recovery system (1) as claimed in claim 2 , characterized in that the leakage quantity (46 a, 46 b) is less than 1% of the maximum volume flow of the working fluid,
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102016205041.9A DE102016205041A1 (en) | 2016-03-24 | 2016-03-24 | spool valve |
DE102016205041.9 | 2016-03-24 | ||
PCT/EP2016/077992 WO2017162319A1 (en) | 2016-03-24 | 2016-11-17 | Waste heat recovery system |
Publications (1)
Publication Number | Publication Date |
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US20190048749A1 true US20190048749A1 (en) | 2019-02-14 |
Family
ID=61656381
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US16/087,715 Abandoned US20190048749A1 (en) | 2016-03-24 | 2016-11-17 | Waste heat recovery system |
Country Status (3)
Country | Link |
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US (1) | US20190048749A1 (en) |
EP (1) | EP3433472A1 (en) |
WO (1) | WO2017162319A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190285027A1 (en) * | 2016-05-18 | 2019-09-19 | Maguelone PONTET | An internal combustion engine and a method for enhancing the yield of an internal combustion engine |
US10844752B2 (en) * | 2016-05-30 | 2020-11-24 | Robert Bosch Gmbh | Exhaust heat recovery system having a working fluid circuit |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10345580B4 (en) * | 2003-09-29 | 2015-06-03 | Amovis Gmbh | Device for generating heat and electricity |
JP4689498B2 (en) * | 2006-03-01 | 2011-05-25 | 株式会社デンソー | Expander and its control device |
JP5106464B2 (en) * | 2009-03-30 | 2012-12-26 | サンデン株式会社 | Fluid machine, refrigerant circuit and waste heat utilization apparatus using fluid machine |
JP5969227B2 (en) * | 2012-03-14 | 2016-08-17 | サンデンホールディングス株式会社 | Fluid machinery |
DE102013222763A1 (en) * | 2013-11-08 | 2015-05-13 | Robert Bosch Gmbh | Waste Heat Recovery System |
-
2016
- 2016-11-17 WO PCT/EP2016/077992 patent/WO2017162319A1/en unknown
- 2016-11-17 US US16/087,715 patent/US20190048749A1/en not_active Abandoned
- 2016-11-17 EP EP16801168.2A patent/EP3433472A1/en not_active Withdrawn
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190285027A1 (en) * | 2016-05-18 | 2019-09-19 | Maguelone PONTET | An internal combustion engine and a method for enhancing the yield of an internal combustion engine |
US10815930B2 (en) * | 2016-05-18 | 2020-10-27 | Kyrdyn | Internal combustion engine and a method for enhancing the yield of an internal combustion engine |
US10844752B2 (en) * | 2016-05-30 | 2020-11-24 | Robert Bosch Gmbh | Exhaust heat recovery system having a working fluid circuit |
Also Published As
Publication number | Publication date |
---|---|
WO2017162319A1 (en) | 2017-09-28 |
EP3433472A1 (en) | 2019-01-30 |
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