U.S. patent application number 14/704712 was filed with the patent office on 2016-11-10 for waste heat recovery hybrid power drive.
The applicant listed for this patent is Cummins, Inc.. Invention is credited to Nimish Bagayatkar.
Application Number | 20160326914 14/704712 |
Document ID | / |
Family ID | 57222462 |
Filed Date | 2016-11-10 |
United States Patent
Application |
20160326914 |
Kind Code |
A1 |
Bagayatkar; Nimish |
November 10, 2016 |
WASTE HEAT RECOVERY HYBRID POWER DRIVE
Abstract
A system includes an internal combustion engine; a waste heat
recovery system in fluid communication with the internal combustion
engine, the waste heat recovery system including an energy
conversion system, wherein the waste heat recovery system is
structured to extract heat energy from the engine, and wherein the
energy conversion system is structured to generate power from the
extracted heat energy; a gear box operatively coupled to an output
of the energy conversion system; and an alternator operatively
coupled to the gear box and the internal combustion engine, wherein
the alternator consumes a first portion of the generated power to
produce electrical energy while a remaining portion of the
generated power is absorbed by the internal combustion engine via a
front end accessory drive system.
Inventors: |
Bagayatkar; Nimish; (Carmel,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cummins, Inc. |
Columbus |
IN |
US |
|
|
Family ID: |
57222462 |
Appl. No.: |
14/704712 |
Filed: |
May 5, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01K 23/065 20130101;
F01K 15/02 20130101 |
International
Class: |
F01K 23/06 20060101
F01K023/06 |
Claims
1. A vehicle, comprising: an internal combustion engine; a waste
heat recovery system in fluid communication with the internal
combustion engine, the waste heat recovery system including an
energy conversion system, wherein the waste heat recovery system is
structured to extract heat energy from the engine, and wherein the
energy conversion system is structured to generate power from the
extracted heat energy; a gear box operatively coupled to an output
of the energy conversion system; and an alternator operatively
coupled to the gear box and the internal combustion engine, wherein
the alternator consumes a first portion of the generated power to
produce electrical energy while a remaining portion of the
generated power is absorbed by the internal combustion engine via a
front end accessory drive system.
2. The vehicle of claim 1, wherein the energy conversion system
includes a waste heat recovery expander and the output is a shaft
of the waste heat recovery expander.
3. The vehicle of claim 2, further comprising a shaft coupling,
wherein the shaft coupling selectively couples to the shaft of the
waste heat recovery expander and to a shaft of the alternator.
4. The vehicle of claim 3, wherein the gear box is structured to
substantially match a speed of rotation of the shaft of the waste
heat recovery expander to an operating shaft speed for the shaft of
the alternator.
5. The vehicle of claim 1, further comprising an electric power
system, the electric power system structured to selectively power
the vehicle in at least one of combination with and separate from
the engine, wherein the electric power system includes at least one
of a variable energy dissipation device, one or more energy storage
devices, and an electric motor.
6. The vehicle of claim 5, wherein the alternator is structured to
selectively charge the one or more energy storage devices via the
produced electrical energy.
7. The vehicle of claim 1, wherein the alternator is a part of the
front end accessory drive system, wherein the alternator includes a
pulley structured to selectively power one or more accessories in
the front end accessory drive system.
8. The vehicle of claim 7, wherein the pulley is coupled to a
clutch configured to selectively couple the pulley to the internal
combustion engine, wherein the clutch is configured to selectively
couple and decouple the pulley from the engine to at least partly
control an operating shaft speed of a shaft of the alternator.
9. The vehicle of claim 8, wherein the clutch is configured to
control the operating shaft speed of the shaft of the alternator to
substantially match a rotational speed for a shaft of a waste haste
recovery expander included in the energy conversion system.
10. The vehicle of claim 7, wherein the one or more accessories
include a power steering pump, an air conditioning compressor, and
a water pump.
11. A system, comprising: an internal combustion engine; a waste
heat recovery system having a working fluid circuit, a fluid
management system positioned along the working fluid circuit that
utilizes a working fluid, a heat exchange system positioned along
the working fluid circuit, and a feedpump positioned along the
working fluid circuit and structured to move the working fluid
through the working fluid circuit; an energy conversion system
positioned along the working fluid circuit downstream from the heat
exchange system and upstream from the fluid management system,
wherein the energy conversion system is structured to generate
power from heat energy extracted from the engine via the waste heat
recovery system; a gear box operatively coupled to an output of the
energy conversion system; a coupling structured to selectively
receive the output of the energy conversion system; and an
alternator operatively coupled to the coupling and the internal
combustion engine, wherein the alternator consumes a first portion
of the generated power to produce electrical energy while a
remaining portion of the generated power is absorbed by the
internal combustion engine via a front end accessory drive
system.
12. The system of claim 11, wherein the energy conversion system
includes a waste heat recovery expander and the output is a shaft
of the waste heat recovery expander.
13. The system of claim 12, wherein the coupling is structured as a
shaft coupling, wherein the shaft coupling selectively couples to
the shaft of the waste heat recovery expander and a shaft of the
alternator.
14. The system of claim 13, wherein the gear box is structured to
substantially match a speed of rotation of the shaft of the
expander to an operating shaft speed for the shaft of the
alternator.
15. The system of claim 13, wherein the alternator is configured to
substantially match a speed of rotation for the shaft of the
alternator to a rotational speed of the shaft of the expander.
16. The system of claim 11, further comprising an electric power
system, the electric power system operable either with or separate
from the engine, wherein the electric power system includes one or
more energy storage devices and an electric motor.
17. The system of claim 16, wherein the alternator is structured to
selectively charge the one or more energy storage devices via the
produced electrical energy.
18. The system of claim 11, further comprising an exhaust gas
recirculation (EGR) circuit, wherein the heat exchange system
further includes an EGR boiler/superheater and a recuperator.
19. The system of claim 18, wherein the fluid management system
includes a condenser, a receiver, and a sub-cooler.
20. The system of claim 19, wherein the fluid management system
includes a valve module, wherein the valve module selectively
facilitates provision of the working fluid to four flow paths in
the waste heat recovery system.
21. A method, comprising: providing an internal combustion engine;
providing a waste heat recovery system in fluid communication with
the internal combustion engine, the waste heat recovery system
including an energy conversion system, wherein the waste heat
recovery system is structured to extract heat energy from the
engine, and wherein the energy conversion system is structured to
generate power from the extracted heat energy; and providing an
alternator operatively coupled to the energy conversion system and
the internal combustion engine, wherein the alternator consumes a
first portion of the generated power to produce electrical energy
while a remaining portion of the generated power is absorbed by the
internal combustion engine via a front end accessory drive
system.
22. The method of claim 21, further comprising providing a gear box
and a coupling, wherein the energy conversion system is coupled to
the gear box, which is coupled to the coupling, which is coupled to
the alternator.
23. The method of claim 21, wherein the energy conversion system
includes a waste heat recovery expander having a shaft, wherein the
shaft is received by the gear box.
Description
TECHNICAL FIELD
[0001] This disclosure relates to Waste Heat Recovery (WHR)
systems. More particularly, the disclosure relates to WHR systems
used with hybrid vehicles.
BACKGROUND
[0002] A waste heat recovery (WHR) system recovers heat energy from
an internal combustion engine that would otherwise be lost. The
more waste heat energy extracted from an internal combustion engine
by a WHR system, the greater the potential efficiency of the
engine. In other words, rather than the extracted heat being lost,
the extracted heat energy may be repurposed to, e.g., supplement
the power output from the internal combustion engine thereby
increasing the efficiency of the system. However, the WHR system
requires energy to operate, such as the energy required to operate
a feedpump to pump a working fluid through the WHR system. The
energy required to operate the WHR system represents a loss to the
efficiency gained from the WHR system.
SUMMARY
[0003] One embodiment relates to a vehicle. The vehicle includes an
internal combustion engine; a waste heat recovery system in fluid
communication with the internal combustion engine, the waste heat
recovery system including an energy conversion system, wherein the
waste heat recovery system is structured to extract heat energy
from the engine, and wherein the energy conversion system is
structured to generate power from the extracted heat energy; a gear
box operatively coupled to an output of the energy conversion
system; and an alternator operatively coupled to the gear box and
the internal combustion engine, wherein the alternator consumes a
first portion of the generated power to produce electrical energy
while a remaining portion of the generated power is absorbed by the
internal combustion engine via a front end accessory drive system.
In one configuration, the vehicle is structured as a hybrid
vehicle. In this configuration, the vehicle includes an electric
power system structured selectively power the vehicle with or
without assistance from the internal combustion engine. In this
configuration, the alternator is structured to provide at least a
portion of the produced electrical energy to the electrical power
system. Advantageously, the provided electrical energy stems from
recovered waste heat energy, which increases the relative
efficiency of the vehicle.
[0004] Another embodiment relates to a system. The system includes
an internal combustion engine; a waste heat recovery system having
a working fluid circuit, a fluid management system positioned along
the working fluid circuit that utilizes a working fluid, a heat
exchange system positioned along the working fluid circuit, and a
feedpump positioned along the working fluid circuit and structured
to move the working fluid through the working fluid circuit; an
energy conversion system positioned along the working fluid circuit
downstream from the heat exchange system and upstream from the
fluid management system, wherein the energy conversion system is
structured to generate power from heat energy extracted from the
engine via the waste heat recovery system; a gear box operatively
coupled to an output of the energy conversion system; a coupling
structured to selectively receive the output of the energy
conversion system; and an alternator operatively coupled to the
coupling and the internal combustion engine, wherein the alternator
consumes a first portion of the generated power to produce
electrical energy while a remaining portion of the generated power
is absorbed by the internal combustion engine via a front end
accessory drive system.
[0005] Still another embodiment relates to a method. The method
includes providing an internal combustion engine; providing a waste
heat recovery system in fluid communication with the internal
combustion engine, the waste heat recovery system including an
energy conversion system, wherein the waste heat recovery system is
structured to extract heat energy from the engine, and wherein the
energy conversion system is structured to generate power from the
extracted heat energy; and providing an alternator operatively
coupled to the energy conversion system and the internal combustion
engine, wherein the alternator consumes a first portion of the
generated power to produce electrical energy while a remaining
portion of the generated power is absorbed by the internal
combustion engine via a front end accessory drive system.
[0006] Advantages and features of the embodiments of this
disclosure will become more apparent from the following detailed
description of exemplary embodiments when viewed in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic of an internal combustion engine with
a WHR system, according to an example embodiment.
[0008] FIG. 2 is a schematic diagram of an alternator, a coupling,
a gearbox, and an expander used with WHR and engine system of FIG.
1, according to an example embodiment.
DETAILED DESCRIPTION
[0009] Referring to the Figures generally, various embodiments
disclosed herein relate to systems and methods of outputting two
forms of energy from a WHR system. According to the present
disclosure, a system includes an engine, WHR system, an alternator,
and a coupling to connect or couple the WHR system to the
alternator. The WHR system extracts power from the WHR working
fluid and outputs it in the form of a torque on a rotating shaft.
Via the coupling, the torque on the rotating shaft is transferred
to the alternator. The alternator may be part of a front end
accessory drive (FEAD) system, such that the alternator powers
front end accessories such as water pumps, power steering pumps,
compressors, etc. The alternator may also receive power from the
crankshaft of the engine. According to the present disclosure, the
alternator consumes or utilizes some of the power extracted by the
WHR system to generate electrical energy while the remainder or
most of the remainder of the extracted energy is absorbed by the
engine via the FEAD system through the crankshaft (i.e., the dual
or two forms of energy).
[0010] Advantageously, by coupling the WHR system with the
alternator, otherwise lost heat energy may be used to generate
electrical energy. According to one embodiment, the present
disclosure is implemented with a hybrid vehicle (vehicles powered
by two different types of energy, such as electrical energy from an
electrical motor and chemical energy via combustion in an internal
combustion engine). Beneficially, relatively more electrical energy
may be generated to power the electrical motor of the hybrid
vehicle than in conventional hybrid vehicles via the coupling to
the alternator. This provides a technical advantage over current
hybrid vehicle technology, which may be appealing to consumers.
These and other features of the present disclosure are more fully
described herein below.
[0011] Referring now to FIG. 1, an engine 10 and waste heat
recovery (WHR) system is shown, according to one embodiment. It
should be noted that the engine 10 and WHR system 12 shown in FIG.
1 is an example configuration. Other configurations may include or
exclude other and different components. For example, in some
embodiments, the exhaust gas recirculation (EGR) system 100 may be
excluded from the system. Similarly, in other embodiments, the
exhaust system may include one or more aftertreatment components,
such as a diesel oxidation catalyst, a diesel particulate filter,
and a selective catalytic reduction catalyst. However, the
principles and disclosure described herein is still applicable to
these variations. Therefore, all of these variations are intended
to fall within the spirit and scope of the present disclosure.
[0012] In the example depicted in FIG. 1 (and FIG. 2), all of the
components depicted are embodied in a vehicle. The vehicle 100 may
be an on-road or an off-road vehicle including, but not limited to,
line-haul trucks, mid-range trucks (e.g., pick-up truck), sedans,
coupes, compacts, sport utility vehicles, and any other type of
vehicle that utilizes cruise control systems.
[0013] As shown, the vehicle is structured as a hybrid vehicle
(e.g., a vehicle that selectively uses two different energy sources
to propel the vehicle). The vehicle includes an engine 10
structured as an internal combustion engine. The internal
combustion engine may include a spark-ignition engine and a
compression ignition engine. Accordingly, the engine 10 may be
fueled by any fuel, such as gasoline, diesel, and ethanol. In
operation, the engine 10 receives a chemical energy input (e.g., a
fuel such as gasoline, diesel, etc.) and combusts the fuel to
generate mechanical energy, in the form of a rotating crankshaft. A
transmission (not shown) receives the rotating crankshaft and
manipulates the speed of the crankshaft to affect a desired drive
shaft speed. The rotating drive shaft is received by a
differential, which provides the rotation energy of the drive shaft
to the final drive (e.g., wheels, etc.). The final drive then
propels or moves the vehicle.
[0014] The vehicle also includes an electric power system 80. The
electric power system 80 is structured to selectively power or
propel the vehicle in combination with or separate from the engine
10. The electric power system 80 includes one or more energy
storage devices 81 (e.g., batteries) and an electric motor 82. The
electric motor 82 receives power from the one or more energy
storage devices 81 to selectively propel the vehicle. The
components shown as part of the electric power system 80 are not
meant to be limiting as the electric power system may include
additional features with additional functionality. For example,
components relating to a regenerative braking system may also be
included in the electric power system. Accordingly, the electric
power system 80 is meant to be broadly interpreted.
[0015] According to one embodiment, the WHR system 12 described
herein is a Rankine cycle waste heat recovery system, or an organic
Rankine cycle if the working fluid is an organic high molecular
mass fluid with a liquid-vapor phase change that is lower than the
water-steam phase change. Examples of Rankine cycle working fluids,
organic and inorganic, include Genetron.RTM. R-245fa from
Honeywell, Therminol.RTM., Dowtherm J.TM. from Dow Chemical Co.,
Fluorinol.RTM. from American Nickeloid, toluene, dodecane,
isododecane, methylundecane, neopentane, neopentane, octane,
water/methanol mixtures, or steam.
[0016] As shown, the WHR system 12 includes a WHR circuit 18, along
which are positioned a fluid management system 20, a fluid control
portion 22, a heat exchange system 24, and an energy conversion
system 26. The fluid management system 20 provides storage or
containment, and cooling for a working fluid of the WHR system 12.
The fluid control portion 22 regulates the flow of the working
fluid throughout the WHR system 12. The heat exchange system 24
provides cooling to certain systems of the engine 10 and serves to
heat the working fluid to permit the working fluid to drive an
energy conversion system 26, extracting useful work or energy from
the waste heat created by the engine 10.
[0017] The fluid management system 20 includes a sub-cooler 28, a
condenser 30, a receiver 32, and a feedpump 34. The receiver 32
serves primarily as a reservoir for the WHR system 12. The
condenser 30 serves to convert gaseous working fluid to liquid
working fluid. The sub-cooler 28 provides cooling to the liquid
working fluid. The condenser 30 may be integral with sub-cooler 28,
may connect to sub-cooler 28 by way of WHR circuit 18, or may be
commonly mounted with sub-cooler 28 on a common base 36, which may
include a plurality of fluid flow paths (not shown) to fluidly
connect the condenser 30 to the sub-cooler 28. The receiver 32 may
be physically elevated higher than sub-cooler 28, and may be
connected to sub-cooler 28 through fluid control portion 22. The
top of receiver 32 includes a vent that may be opened to the
condenser 30 by way of a vent valve 38. A fluid level sensor 40 is
positioned along WHR circuit 18 in a location suitable to determine
the level of the liquid working fluid in sub-cooler 28 and
condenser 30. The feedpump 34 is positioned along WHR circuit 18
downstream from sub-cooler 28 and upstream from fluid control
portion 22. The fluid management system 20 may also include one or
more filter driers 42 positioned along WHR circuit 18 downstream
from fluid control portion 22. Alternatively, the filter drier 42
may be positioned downstream from the feedpump 34 and upstream from
the fluid control portion 22. All such variations are intended to
fall within the spirit and scope of the present disclosure.
[0018] The fluid control portion 22 includes a plurality of valves
and an ejector 56 configured to regulate flow as needed throughout
WHR system 12. The valves include actuated on-off valves 44 and 46,
actuated proportional valves 48 and 50, actuated vent valve 38, and
passive check valves 52 and 54. In one embodiment, the ejector 56
is a passive device and operates in conjunction with certain valves
to draw liquid working fluid from receiver 32. Many of the valves
and ejector 56 may be included within a valve module or body 58.
The function of the various valves and ejector 56 is to control the
flow of working fluid in WHR system 12, which also controls the
heat transferred to and from the working fluid flowing through WHR
circuit 18. Though electrically actuated valves 38, 44, 46, 48, and
50 may be described as on-off or proportional valves, this
description is for convenience in the context of the exemplary
embodiment. The on-off valves may be proportional valves and the
proportional valves may be modulated valves capable of opening and
closing rapidly to adjust the amount of working fluid flowing
through the valves.
[0019] The heat exchange system 24 includes a recuperator 88, an
EGR boiler 60, an EGR superheater 62, an exhaust heat exchanger 64,
and an exhaust control valve 66. The EGR boiler 60 provides the
ability to regulate the temperature of an EGR gas by transferring
heat from the EGR gas to the working fluid. It should be understood
that the term "EGR boiler" is used for the sake of convenience. EGR
boiler 60 may serve more than one function for system, such as
cooling the EGR gas and transferring heat from the EGR gas to the
working fluid of WHR system 12. The exhaust heat exchanger 64
permits the controlled transfer of heat from the exhaust of the
engine 10 to the working fluid. The amount of heat available to
exhaust heat exchanger 64 is determined by exhaust control valve
66. The EGR superheater 62 transfers additional heat energy from
the EGR gas to the working fluid, which is in a gaseous state when
it enters EGR superheater 62. The EGR superheater 62 is positioned
along WHR circuit 18 downstream from exhaust heat exchanger 64 and
upstream from condenser 30.
[0020] The exhaust heat exchanger 64 is positioned along the
exhaust gas circuit 100. The exhaust gas circuit 100 fluidly
connects an upstream aftertreatment system 102 to exhaust heat
exchanger 64. The exhaust control valve 66 is positioned between
aftertreatment system 102 and exhaust heat exchanger 64. Both the
exhaust control valve 66 and the exhaust heat exchanger 64 are
fluidly connected on their downstream sides by exhaust gas circuit
100 to an atmospheric vent 104, which may be a tailpipe, exhaust
pipe, exhaust stack, or the like.
[0021] The EGR superheater 62 and EGR boiler 60 are connected to a
portion of an EGR circuit 106. EGR gas flows along EGR circuit 106
into the EGR superheater 62 and then downstream from EGR
superheater 62 into the EGR boiler 60. From the EGR boiler 60, the
EGR gas flows downstream along EGR circuit 106. The EGR superheater
62 and the EGR boiler 60 serve as heat exchangers for the EGR
circuit 106, providing a cooling function for the EGR gas flowing
through EGR superheater 62 and EGR boiler 60. The EGR superheater
62 and the EGR boiler 60 also serve as heat exchangers for the WHR
circuit 18, raising the temperature of working fluid flowing
through EGR boiler 60 and through the EGR superheater 62.
[0022] As shown, the fluid control portion 22 may include a
plurality of parallel flow path portions formed along the WHR
circuit 18 that connect the feedpump 34 to various elements of the
WHR system 12. A first flow path portion 90 fluidly connects the
downstream side of the feedpump 34 to the receiver 32. Positioned
along the first flow path portion 90 between the feedpump 34 and
the receiver 32 is a proportional valve 48, which is downstream
from the feedpump 34 and upstream from the receiver 32. Positioned
along the first flow path portion 90 between the proportional valve
48 and the receiver 32 is an on-off valve 44. Though not part of
the first flow path portion 90, a vent valve 38 is positioned along
the WHR circuit 18 between the receiver 32 and the condenser 30.
The purpose of the vent valve 38 is to permit vapor to move into
and out from the receiver 32 as liquid working fluid is moved out
from and into the receiver 32 along the first flow path portion
90.
[0023] A second flow path portion 92 extends from a location along
the first flow path portion 90 between the proportional valve 48
and the on-off valve 44 to fluidly connect to the sub-cooler 28 and
the condenser 30. The passive check valve 52 is positioned along
the second flow path portion 92, and the ejector 56 is positioned
along the second flow path portion 92 between the passive check
valve 52 and the sub-cooler 28 and/or the condenser 30, downstream
from the passive check valve 52 and upstream from the sub-cooler 28
and/or the condenser 30. The first flow path portion 90 is also
connected to the second flow path portion 92 by a connection path
portion 94, which extends from a location between the on-off valve
44 and the receiver 32 to the ejector 56. The on-off valve 46 is
positioned along connection path portion 94.
[0024] A third flow path portion 96, which is parallel to the first
flow path portion 90 and to the second flow path portion 92,
fluidly connects the feedpump 34 to the recuperator 88. The passive
check valve 54 is positioned along the third flow path portion 96,
between the feedpump 34 and the recuperator 88. The recuperator 88
is connected on a downstream side to the exhaust heat exchanger 64.
The filter drier 42 may be positioned along the WHR circuit 18
between the recuperator 88 and the passive check valve 54. The
recuperator 88 is also positioned along the WHR circuit 18 between
the energy conversion system 26 and the condenser 30, downstream
from the energy conversion system 26 and upstream from the
condenser 30.
[0025] A fourth flow path portion 98, which is parallel to the
first flow path 90, second flow path portion 92, and third flow
path portion 96, fluidly connects the feedpump 34 to the EGR boiler
60. The exhaust heat exchanger 64 is positioned downstream from the
EGR boiler 60 and the recuperator 88. Thus, any working fluid flow
along third flow path portion 96 and working fluid flow along
fourth flow path portion 98 converges prior to entry into the
exhaust heat exchanger 64. The proportional valve 50 is positioned
along fourth flow path portion 98 downstream from the feedpump 34
and upstream from the engine heat exchanger 60. A filter drier 42
may be positioned along the WHR circuit 18 downstream from the
proportional valve 50 and upstream from the EGR boiler 60.
[0026] With the components of the WHR system 12 described above,
operation of the WHR system 12 may be described as follows. The
sub-cooler 28 stores the liquid working fluid. The feedpump 34
pulls or draws liquid working fluid from the sub-cooler 28. The
feedpump 34 then forces liquid working fluid downstream to the
valve module 58. In the valve module 58, the flow of liquid working
fluid may be directed to one of four parallel flow path portions.
As described above, the first flow path portion 90 connects the
feedpump 34 to the receiver 32, the second flow path portion 92
connects the feedpump 34 to the condenser 30/sub-cooler 28, the
third flow path portion 96 connects the feedpump 34 to the
recuperator 88, and the fourth flow path portion 98 connects
feedpump 34 to EGR boiler 60. It should be understood that these
flow paths are exemplary as more or less flow paths may be used in
other systems and arrangements.
[0027] During normal operation of the engine 10, the proportional
valve 48 is at least partially open to permit liquid working fluid
to flow into the first flow path portion 90 and then into the
second flow path portion 92, flowing through the passive check
valve 54, which may have a cracking or opening pressure threshold
(e.g. five psi), so that liquid working fluid flows through the
second flow path portion to the sub-cooler 28, thus forming a
continuous loop of flowing liquid working fluid when check valve 52
opens. If the proportional valve 48 is opened and on/off valve 44
is closed, liquid working fluid flows into the first flow path
portion 90 into the second flow path portion 92, which may be used
to prevent the two-phase working fluid flow, i.e., liquid and gas,
from reaching the energy conversion system 26. If the on-off valve
44 is opened when proportional valve 48 is opened, the on-off valve
46 is closed, and the vent valve 38 is opened, the cracking
pressure of the check valve 52 causes liquid working fluid to flow
upwardly along first flow path portion 90 to the receiver 32. The
flow of fluid into the receiver 32 causes the level of liquid
working fluid in the receiver 32 to increase, and causes the level
of liquid working fluid in the sub-cooler 28 and/or the condenser
30 to decrease. Thus, in this valve configuration the feedpump 34
may be connected simultaneously to the sub-cooler 28 and to the
receiver 32.
[0028] If the on-off valve 46 is open, the on-off valve 44 is
closed, and the vent valve 38 is open while liquid working fluid
flows from the feedpump 34 along first flow path portion 90 into
the second flow path portion 92 and then into sub-cooler 28 and/or
condenser 30, then the receiver 32 is connected to the sub-cooler
28 and/or the condenser 30 along a portion of the WHR circuit 18
that is parallel to the portion of the WHR circuit 18 that connects
the feed pump 34 to the sub-cooler 28 and/or the condenser 30. In
this valve configuration, liquid working fluid will be drawn from
receiver 32, flowing through a portion of the first flow path
portion 90 through the on-off valve 46, which is positioned along
the connection path portion 94, into the ejector 56. The liquid
working fluid then flows downstream from the ejector 56 to the
sub-cooler 28 and the condenser 30, increasing the level of liquid
working fluid in the sub-cooler 28 or in the condenser 30. The
level of liquid working fluid may vary sufficiently that the
condenser 30 may contain some liquid working fluid. The increase in
the level of the liquid working fluid in sub-cooler 28 increases
sub-cooling, adjusting the saturation temperature of the liquid
working fluid. The vent valve 38 is normally open during operation
of engine 10, which permits vapor to flow to and from the top
portion of receiver 32 to and from a top portion of condenser 30,
permitting the level of liquid working fluid in receiver 32 to
increase or decrease. Once the level of liquid working fluid has
been increased in sub-cooler 28 and/or condenser 30 a desirable
amount, the on-off valve 46 is closed, stopping flow from receiver
32 through connection path portion 94.
[0029] Liquid working fluid flows along the third flow path portion
96 based on the opening of proportional valve 50 positioned along
the fourth flow path portion 98. Passive check valve 54 creates a
backpressure along the upstream portion of third flow path portion
96, which biases the flow of liquid working fluid along fourth flow
path portion 98. By partially closing the proportional valve 50,
the backpressure along the upstream portion of the fourth flow path
portion 98 increases, until passive check valve 54 cracks or opens
under the increased backpressure from the proportional valve 50.
Relatively small amounts of liquid working fluid normally flow
through the first flow path portion 90 and the second flow path
portion 92, so most of the liquid working fluid provided to the WHR
circuit 18 by the feedpump 34 flows through the third flow path
portion 96 and the fourth flow path portion 98. Flow of working
fluid through the third flow path portion 96 and the fourth flow
path portion 98 converges upstream from the exhaust heat exchanger
64.
[0030] Cooling of exhaust gas in the exhaust heat exchanger 64 is
an optional function that may be reduced in favor of cooling of EGR
gas in the EGR boiler 60. Thus, the configuration of these
components is advantageous in providing priority cooling to the EGR
gas. Additional heat may then be added to the working fluid as
needed in the exhaust heat exchanger 64 and the EGR superheater 62
by the WHR system 12 to obtain optimal superheating of the working
fluid. The working fluid, which is in a gaseous state because of
heat transfer from the above-described heat exchangers, flows from
exhaust gas heat exchanger 64 into the EGR superheater 62, where
additional heat energy is added to the gaseous working fluid. The
superheated gaseous working fluid flows from the EGR superheater 62
into energy conversion device 68.
[0031] The flow of the working fluid through the WHR system 12
extracts heat energy. As described herein, the heat energy may be
used by the energy conversion system 26 to transfer energy to
another system or device.
[0032] It should be understood that in certain embodiments, the WHR
system 12 further includes a controller structured to perform
certain operations to control or regulate the flow of the working
fluid through the system 12. In certain embodiments, the controller
forms a portion of a processing subsystem including one or more
computing devices having memory, processing, and communication
hardware. The controller may be a single device or a distributed
device, and the functions of the controller may be performed by
hardware and/or as computer instructions on a non-transient
computer readable storage medium. In certain embodiments, the
controller includes one or more modules structured to functionally
execute the operations of the controller. Modules may be
implemented in hardware and/or as computer instructions on a
non-transient computer readable storage medium, and modules may be
distributed across various hardware or computer based components.
To facilitate the accurate control by the controller, the WHR
system 12 may include one or more sensors strategically positioned
and communicatively coupled to the controller. The sensors may
include, but are not limited to, temperature sensors, pressure
sensors, flow sensors, etc. Accordingly, example and non-limiting
module implementation elements include sensors, like described
above, providing any value used by the controller, sensors
providing any value that is a precursor to a value determined,
datalink and/or network hardware including communication chips,
oscillating crystals, communication links, cables, twisted pair
wiring, coaxial wiring, shielded wiring, transmitters, receivers,
and/or transceivers, logic circuits, hard-wired logic circuits,
reconfigurable logic circuits in a particular non-transient state
configured according to the module specification, any actuator
including at least an electrical, hydraulic, or pneumatic actuator,
a solenoid, an op-amp, analog control elements (springs, filters,
integrators, adders, dividers, gain elements), and/or digital
control elements.
[0033] Referring now to FIG. 1 in connection with FIG. 2,
description of the components located in section 200 is now
explained. As mentioned above, the WHR system 12 is operatively
coupled to an energy conversion system 26. The energy conversion
system 26 is structured to produce additional work or transfer
energy to another device or system. The energy conversion system 26
is shown to include an energy conversion device 68. The energy
conversion system 26 may be a turbine, piston, scroll, screw, or
other type of expander device that moves, e.g., rotates, as a
result of expanding working fluid vapor to provide additional work.
Alternatively, energy conversion system 26 can be used to transfer
energy from one system to another system (e.g., to transfer heat
energy from WHR system 12 to a fluid for a heating system). The
energy conversion device 68 is positioned along the WHR circuit 18
and is downstream from the EGR superheater 62 and upstream from the
condenser 30 in this embodiment.
[0034] According to the present disclosure, the energy conversion
device 68 is operatively coupled to an energy transfer device,
shown as gear box 108. In this embodiment, the energy conversion
device 68 is structured as an expander (FIG. 2). The expander
receives and expands the working fluid from the WHR system 12 to
generate power in the form of a rotating shaft. The rotating shaft
is received by the gear box 108. The gear box 108 is structured to
include one or more gear trains corresponding to one or more gear
ratios (expander shaft input-to-gear box output). The gear box 108
is structured to reduce a speed of rotation of the shaft of the
expander 68 to an operating shaft speed of the shaft of the
alternator 110. For example, the alternator 110 may have a
prescribed operating shaft speed. The gear box 108 is structured to
match or substantially match the expander shaft speed with that
operating speed of the alternator shaft. Therefore, in some
embodiments, the gear box 108 may act like an overdrive and
increase the expander shaft speed while in other embodiments the
gear box 108 may reduce the expander shaft speed to align or
substantially align with the intended operating speed of the
alternator 110 shaft. In this regard, the system of the present
disclosure may maintain or nearly maintain efficient operation of
the alternator 110. According to another embodiment, the alternator
110 may utilize electric load balancing (e.g., altering the torque
applied to the shaft of the alternator 110 by selectively adjusting
the current in the windings) to control a speed of the alternator
shaft to enhance speed matching between the expander 68 and the
alternator 110. According to an alternate embodiment, the gear box
108 may be removed from the system, such that the alternator 110,
via electric load balancing, synchronizes or substantially
synchronizes the speed of the expander shaft to the alternator
shaft.
[0035] The alternator 110 is structured as an on-engine 10
alternator. Accordingly, the alternator 110 may be coupled to a
crankshaft of the engine 10. In other embodiments, the alternator
110 may be replaced with a high capacity alternator for additional
electrical power and charging capacity.
[0036] As shown, the alternator 110 is coupled to a coupling 120.
The coupling 120 is operatively coupled to both the alternator 110
and the gear box 108. In one embodiment, the coupling 120 is
structured as a shaft coupling thereby permitting the coupling of a
shaft of the alternator 110 to an output shaft of the gear box 108.
In one embodiment, the coupling 120 may selectively engage with at
least one of the alternator 110 shaft and the output shaft of the
gear box 108. For example, the coupling 120 may be
electromechanically actuated via the controller (described above).
In this regard, the coupling 120 may selectively transfer power
from the expander 68 to the alternator 110 (or, in certain
embodiments, vice versa).
[0037] The alternator 110 is shown to include a front end accessory
drive (FEAD) pulley 111. The FEAD pulley 111 operatively couples
(e.g., via one or more belts, such as a serpentine belt and a fan
belt, gear chains, etc.) to one or more front end accessories 112
in the vehicle. In this regard, according to another embodiment,
the pulley 111 may be structured gear. The gear may be operatively
coupled to the engine 10 or integrated into the engine gear train.
All such configurations for the pulley 111 are intended to fall
within the spirit and scope of the present disclosure. The one or
more front end accessories 112 may include, but are not limited to,
a water pump, an air conditioning compressor, and a power steering
pump. The one or more front end accessories 112 is shown in a
dashed line on FIG. 1 to indicate that the alternator 110 may
selectively power some of the accessories.
[0038] According to one embodiment, the alternator 110 is coupled
to a clutch 113, where the clutch 113 is coupled to the engine 10.
The clutch 113 may be any type of clutch mechanism that can
selectively couple and decouple the alternator 110 to and from the
engine 10. In certain embodiments, the clutch 113 may be actuated
via the controller (such as the one described above) to selectively
control when the alternator (e.g., a shaft of the alternator) is
coupled to the engine 10 and, therefore, driven at least in part by
the engine 10. In this regard, the alternator 110 shaft speed may
be controlled via operation of the clutch. This speed control
feature may be used independent of or in combination with the
electric load balancing of the alternator 110 and operation of the
gear box 108.
[0039] In one embodiment, like shown in FIG. 1, the alternator 110
is also operatively coupled to the electric power system 80. The
coupling may be via any fashion (such as via a belt, electrical
contacts, etc.). In one embodiment, the alternator 110 is
electrically coupled to the one or more energy storage devices 81,
such that the alternator 110 may selectively charge the one or more
energy storage devices 81. In another embodiment, the alternator
110 is directly coupled to the electrical motor 82, such that the
alternator 110 directly powers the electrical motor 82. In still
another embodiment, the alternator 110 is coupled to a variable
energy dissipation device 83 (e.g., a load bank such as a resistive
load bank, etc.) in the vehicle that may be used for a variety of
uses in the vehicle, such as braking In other variations, the
alternator 110 may be selectively coupled to each of the one or
more energy storage devices 81 and the electrical motor 82.
Therefore, in operation, some of the generated power from the
extracted waste heat is used to produce electrical energy by the
alternator 110 which may be provided to the electric power system.
In other embodiments, the produced electrical energy may be
provided to other places as well (e.g., one or more
electrically-actuated sensors or valves, etc.).
[0040] With reference primarily to FIG. 2, operation of the section
200 may be described as follows. The WHR system 12 directs working
fluid to the energy conversion device, which is embodied as an
expander 68 in FIG. 2. The expander 68 is any device which extracts
power from the waste heat recovery working fluid. The expander 68
generates power from the heat energy recovered from the engine 10.
The generated output power is in the form of a torque on a rotating
shaft of the expander 68. The rotating shaft is received by the
gear box 108. The gear box 108 matches the expander rotating shaft
speed to the alternator 110 operating shaft speed for a given
engine. That is, the alternator shaft speed may vary based on the
engine. In other embodiments, and as described above, a clutch such
as clutch 113 may couple the alternator to the engine to
selectively control the alternator shaft speed to enhance speed
matching with the expander. The gear box 108 output shaft is
coupled to the alternator shaft by coupling 120.
[0041] Thus, the alternator 110 may receive power from at least one
of the engine 10 (e.g., a crankshaft) and via the WHR system 12 via
the coupling 120, gear box 108, and energy conversion device 68. In
this regard, the alternator 110 consumes WHR power to generate
electrical energy and the remainder is transferred back to the
engine via the FEAD through the crankshaft of the engine.
Advantageously, this additional amount of energy from the WHR
system 12 may be used to power or charge the electrical power
system 80 of a hybrid vehicle. This supplemental energy from the
WHR system 12 that is routed via the alternator 110 is an
additional energy source that may increase the efficiency of the
hybrid vehicle of the present disclosure.
[0042] It should be understood that while the systems described
herein relate to the use of shaft couplings and gear boxes,
Applicants contemplate other energy transfer mechanism (e.g.,
inductive energy transfer, etc.) that may be used in addition or in
place of the gear box and shaft coupling. Accordingly, many
different mechanisms may be contemplated by those of ordinary skill
in the art that could serve as obvious replacements for the
features and components described herein. These obvious variants
are intended to fall within the spirit and scope of the present
disclosure.
[0043] It should be noted that the term "example" as used herein to
describe various embodiments is intended to indicate that such
embodiments are possible examples, representations, and/or
illustrations of possible embodiments (and such term is not
intended to connote that such embodiments are necessarily
extraordinary or superlative examples).
[0044] While various embodiments of the disclosure have been shown
and described, it is understood that these embodiments are not
limited thereto. The embodiments may be changed, modified and
further applied by those skilled in the art. Therefore, these
embodiments are not limited to the detail shown and described
previously, but also include all such changes and
modifications.
[0045] Additionally, the format and symbols employed are provided
to explain the logical steps of the schematic diagrams and are
understood not to limit the scope of the methods illustrated by the
diagrams. Although various arrow types and line types may be
employed in the schematic diagrams, they are understood not to
limit the scope of the corresponding methods. Indeed, some arrows
or other connectors may be used to indicate only the logical flow
of a method. Additionally, the order in which a particular method
occurs may or may not strictly adhere to the order of the
corresponding steps shown.
* * * * *