High-flow high-efficiency EGR cooler

Abstract

The subject matter herein may be generally embodied as a heat exchanger device comprising: a first fluid conduit defining a first fluid flow path for a first fluid and comprising a fluid diode at least partially fluidically dipolar and formed of a thermally conductive material, the first fluid conduit defining a second fluid flow path for the first fluid; the fluid diode has a first fluid inlet, a first fluid outlet, a first sub-conduit extending from the fluid inlet to the fluid outlet, and a second sub-conduit extending as a local loop from the first sub-conduit proximal to the fluid inlet to the first sub-conduit proximal to the fluid outlet, and the local loop defines a cavity extending through the local loop; and a second fluid conduit in thermal communication with the first fluid conduit and defining a second fluid flow path for a second fluid fluidly isolated from the first fluid flow path through the local loop.

Description

[0001] Priority declaration

[0002] This application claims priority to U.S. patent application No. 18 / 225,429, filed on July 24, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present document relates to an exhaust gas recirculation (EGR) intercooler, and more particularly to an EGR intercooler having a fluid diode function. Background Art

[0004] Internal combustion engine thermal efficiency is limited in part by the ability or lack of ability to increase exhaust gas recirculation (EGR) flow at peak torque conditions without creating other system deficiencies. This is due to the small pressure difference between the exhaust manifold and the intake manifold. Due to this limitation, previous internal combustion engines (ICE) were unable to operate at higher brake thermal efficiency (BTE). Summary of the invention

[0005] Generally speaking, this document discusses an exhaust gas recirculation (EGR) intercooler having a fluid diode function.

[0006] In a first example, a heat exchanger device includes: a first fluid conduit, the first fluid conduit defining a first fluid flow path for a first fluid and including a fluid diode, the fluid diode being at least partially fluid-dipolar and formed of a thermally conductive material, the fluid diode including a first fluid inlet, a first fluid outlet, a first sub-conduit extending from the fluid inlet to the fluid outlet, and a second sub-conduit extending as a local loop from the first sub-conduit proximal to the fluid inlet to the first sub-conduit proximal to the fluid outlet, the local loop defining a cavity extending through the local loop; and a second fluid conduit, the second fluid conduit being thermally connected to the first fluid conduit and defining a second fluid flow path for a second fluid passing through the local loop and fluidically isolated from the first fluid flow path.

[0007] In a second example according to the first example, the fluid diode partially defines a second fluid conduit, and the cavity partially defines a second fluid flow path.

[0008] In a third example according to the first example, the second fluid conduit is formed of another thermally conductive material and extends through the cavity.

[0009] In a fourth example according to the first to third examples, the fluid diode includes a Tesla valve.

[0010] In a fifth example according to the first to third examples, the first sub-conduit defines the first fluid flow path as a substantially linear fluid flow path from the fluid inlet to the fluid outlet.

[0011] In a sixth example according to the first to third examples, the second sub-conduit defines the second fluid flow path as a substantially curved fluid flow path having a predetermined radius.

[0012] In a seventh example according to the first to third examples, the fluid inlet includes a third sub-conduit, the third sub-conduit defines a first basically linear fluid flow path, the first sub-conduit defines the first fluid flow path as a second basically linear fluid flow path arranged at a first predetermined angle to the first basically linear fluid flow path, and the second sub-conduit includes: a curved segment, the curved segment is fluidly connected to the first sub-conduit and extends away from the first sub-conduit in a manner that forms a second predetermined angle with the first sub-conduit; and a linear segment, the linear segment is configured to fluidly connect the third sub-conduit and the curved segment, the linear segment defines a third basically linear fluid flow path that is substantially aligned with the first basically linear fluid flow path.

[0013] In an eighth example according to the seventh example, the linear segment has a predetermined length, and the minimum radius of the curved segment is approximately Wherein, α is a first predetermined angle.

[0014] In a ninth example according to the seventh example, the first predetermined angle ranges from about 10 degrees to about 80 degrees.

[0015] In a tenth example according to the first to third examples, the heat exchanger device further includes: a first inlet manifold, the first inlet manifold is fluidically connected to the first fluid inlet and is configured to supply the first fluid to the first fluid conduit; a second inlet manifold, the second inlet manifold is fluidically connected to the second inlet of the second fluid conduit and is configured to supply the second fluid to the second fluid conduit; a first outlet manifold, the first outlet manifold is fluidically connected to the first fluid outlet; and a second outlet manifold, the second outlet manifold is fluidically connected to the second fluid outlet of the second fluid conduit.

[0016] In an eleventh example, a heat exchanger device includes: a first fluid conduit, the first fluid conduit defining a first fluid flow path and being configured as a Tesla valve, the Tesla valve including at least one local loop defining an annular portion; and a second fluid conduit, the second fluid conduit being thermally connected to the first fluid conduit and defining a second fluid flow path through the annular portion that is different from the first fluid flow path.

[0017] In a twelfth example according to the eleventh example, the Tesla valve includes a plurality of partial loops fluidly connected to each other and defining a first fluid flow path.

[0018] In a thirteenth example according to the eleventh to twelfth examples, the heat exchanger device also includes: a first inlet manifold, the first inlet manifold is configured to supply a first fluid to a first fluid conduit, wherein the first fluid conduit includes another Tesla valve arranged in parallel with the Tesla valve fluid; a first outlet manifold, the first outlet manifold is configured to receive the first fluid from the first fluid conduit; a second inlet manifold, the second inlet manifold is configured to supply a second fluid to a second fluid conduit, wherein the second fluid conduit includes a plurality of second fluid flow paths through one or more of a plurality of local loops; and a second outlet manifold, the second outlet manifold is configured to receive a second fluid from the second fluid conduit.

[0019] In a fourteenth example based on the eleventh example, the first fluid includes combustion exhaust gas, and the second fluid includes a coolant fluid configured to absorb thermal energy transferred away from the combustion exhaust gas.

[0020] In a fifteenth example, a heat exchange method includes: allowing a first fluid to flow along a first direction through a first fluid conduit, the first fluid conduit being configured as a Tesla valve, the Tesla valve defining a first fluid flow path and including at least one local loop defining an annular portion; and allowing a second fluid different from the first fluid to flow through a second fluid flow path different from the first fluid flow path and at least partially defined by the annular portion.

[0021] In a sixteenth example based on the fifteenth example, the method further includes: receiving combustion exhaust gas from an exhaust manifold of an internal combustion engine; providing the combustion exhaust gas as a first fluid; cooling the combustion exhaust gas by transferring heat energy from the combustion exhaust gas to a second fluid; and providing the cooled combustion exhaust gas to an intake manifold of the internal combustion engine.

[0022] In a seventeenth example according to the fifteenth example or the sixteenth example, causing a first fluid to flow in a first direction through a first fluid conduit of a Tesla valve configured to define a first fluid flow path and including at least one local loop defining an annular portion includes: causing the first fluid to flow along a first substantially straight portion of the first fluid flow path through an intersection with the local loop; redirecting the first fluid at a predetermined angle of about 10 degrees to about 80 degrees through the first fluid conduit; and causing the first fluid to flow along a second substantially straight portion of the first fluid flow path.

[0023] In an eighteenth example according to the fifteenth example or the sixteenth example, the method further includes: flowing the first fluid through the first fluid flow path in a second direction opposite to the first fluid flow direction; and obstructing fluid flow in the second direction through the fluid flow path.

[0024] In a nineteenth example according to the eighteenth example, causing the first fluid to flow through the first fluid flow path along a second direction opposite to the flow direction of the first fluid includes: causing a first portion of the first fluid flow to flow along a substantially straight portion of the first fluid flow path; causing a second portion of the first fluid flow to flow along a curved portion of the first fluid flow path toward an intersection of the curved portion and the substantially straight portion; and recombine the first portion of the first fluid flow and the second portion of the first fluid flow proximal to the intersection; and obstructing the fluid flow along the second direction through the fluid flow path includes: fluidly interfering with the first fluid flow by flowing the second fluid and based on the recombination.

[0025] In the twentieth example according to the nineteenth example, the substantially straight portion has a predetermined length L; and the minimum radius of the curved portion is approximately Here, α is the predetermined angle at the intersection point.

[0026] In another exemplary embodiment, a heat exchanger device includes: a first fluid conduit, the first fluid conduit defining a first fluid flow path for a first fluid, and including a fluid diode, the fluid diode being at least partially fluid-dipolar and formed of a thermally conductive material, the fluid diode having a first fluid inlet, a first fluid outlet, a first sub-conduit extending from the fluid inlet to the fluid outlet, and a second sub-conduit extending as a local loop from the first sub-conduit proximal to the fluid inlet to the first sub-conduit proximal to the fluid outlet and defining a cavity extending through the local loop; and a second fluid conduit, the second fluid conduit being thermally connected to the first fluid conduit and defining a second fluid flow path for a second fluid passing through the local loop and fluidically isolated from the first fluid flow path.

[0027] Various embodiments may include some, all, or none of the following features. The fluid diode may partially define a second fluid conduit, and the cavity may partially define a second fluid flow path. The second fluid conduit may be formed of another thermally conductive material and may extend through the cavity. The fluid diode may be a Tesla valve. The first sub-conduit may define the first fluid flow path as a substantially linear fluid flow path from the fluid inlet to the fluid outlet. The second sub-conduit may define the second fluid flow path as a substantially curved fluid flow path having a predetermined radius. The fluid inlet may include a third sub-conduit, the third sub-conduit defining a first substantially linear fluid flow path, the first sub-conduit defining the first fluid flow path as a second substantially linear fluid flow path arranged at a first predetermined angle to the first substantially linear fluid flow path, and the second sub-conduit may include: a curved section, the curved section is in fluid communication with the first sub-conduit, extending away from the first sub-conduit in a manner that is at a second predetermined angle to the first sub-conduit; and a linear section, the linear section is configured to fluidly connect the third sub-conduit and the curved section, and the linear section defines a third substantially linear fluid flow path substantially aligned with the first substantially linear fluid flow path. The linear segment may have a predetermined length L, and the minimum radius of the curved segment may be approximately Wherein, α is a first predetermined angle. The first predetermined angle ranges from about 10 degrees to about 80 degrees. The heat exchanger device may also include: a first inlet manifold, the first inlet manifold is fluidically connected to the first fluid inlet and is configured to supply the first fluid to the first fluid conduit; a second inlet manifold, the second inlet manifold is fluidically connected to the second inlet of the second fluid conduit and is configured to supply the second fluid to the second fluid conduit; a first outlet manifold, the first outlet manifold is fluidically connected to the first fluid outlet; and a second outlet manifold, the second outlet manifold is fluidically connected to the second fluid outlet of the second fluid conduit.

[0028] In another exemplary embodiment, a heat exchanger device includes: a first fluid conduit, the first fluid conduit defining a first fluid flow path and configured as a Tesla valve, the Tesla valve having at least one partial loop defining an annular portion; and a second fluid conduit, the second fluid conduit being thermally connected to the first fluid conduit and defining a second fluid flow path through the annular portion that is different from the first fluid flow path.

[0029] Various embodiments may include some, all, or none of the following features. The Tesla valve may have a plurality of local loops that are fluidly interconnected and define a first fluid flow path. The heat exchanger may include: a first inlet manifold, the first inlet manifold configured to supply a first fluid to a first fluid conduit, wherein the first fluid conduit may include another Tesla valve arranged in fluid parallel with the Tesla valve; a first outlet manifold, the first outlet manifold configured to receive the first fluid from the first fluid conduit; a second inlet manifold, the second inlet manifold configured to supply a second fluid to a second fluid conduit, wherein the second fluid conduit may include a plurality of second fluid flow paths through one or more of the plurality of local loops; and a second outlet manifold, the second outlet manifold configured to receive the second fluid from the second fluid conduit. The first fluid may be a combustion exhaust gas, and the second fluid may be a coolant fluid configured to absorb thermal energy transferred away from the combustion exhaust gas.

[0030] In another exemplary embodiment, a heat exchange method includes: causing a first fluid to flow in a first direction through a first fluid conduit, the first fluid conduit being configured as a Tesla valve, the Tesla valve defining a first fluid flow path and including at least one partial loop defining an annular portion; and causing a second fluid different from the first fluid to flow through a second fluid flow path different from the first fluid flow path and at least partially defined by the annular portion.

[0031] Various embodiments may include some, all, or none of the following features. The method may include: receiving combustion exhaust from an exhaust manifold of an internal combustion engine; providing the combustion exhaust as a first fluid; cooling the combustion exhaust by transferring heat energy from the combustion exhaust to a second fluid; and providing the cooled combustion exhaust to an intake manifold of the internal combustion engine. A first fluid conduit for flowing a first fluid in a first direction through a Tesla valve configured to define a first fluid flow path and having at least one local loop defining an annular portion may include: flowing the first fluid along a first substantially straight portion of the first fluid flow path through an intersection with the local loop; redirecting the first fluid at a predetermined angle of about 10 degrees to about 80 degrees through the first fluid conduit; and flowing the first fluid along a second substantially straight portion of the first fluid flow path. The method may include: flowing the first fluid through the first fluid flow path in a second direction opposite to the first fluid flow direction; and obstructing fluid flow in the second direction through the fluid flow path. Causing a first fluid to flow through a first fluid flow path in a second direction opposite to the first fluid flow direction may include: causing a first portion of the first fluid flow to flow along a substantially straight portion of the first fluid flow path; causing a second portion of the first fluid flow to flow along a curved portion of the first fluid flow path toward an intersection of the curved portion and the substantially straight portion; and recombine the first portion of the first fluid flow and the second portion of the first fluid flow proximal to the intersection; and obstructing fluid flow in the second direction through the fluid flow path includes: fluidly interfering with the first fluid flow by the second fluid flow and upon recombination. The substantially straight portion may have a predetermined length L, and the minimum radius of the curved portion may be approximately Here, α is the predetermined angle at the intersection point.

[0032] The systems and techniques described herein may provide one or more of the following advantages. First, the system may reduce the fuel usage of the engine. Second, the system may reduce the emissions of the engine. Third, the system may reduce the exhaust back pressure. Fourth, the system may achieve improved spark timing. Fifth, the system may reduce the cost of exhaust aftertreatment. Sixth, the system may improve the measurement of exhaust gas recirculation. Seventh, the system may smooth transient operation. Eighth, the system may improve the accuracy of torque and / or speed control.

[0033] The details of one or more embodiments are set forth in the accompanying drawings and the description that follows. Other features and advantages will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of an exemplary engine system.

[0035] Figure 2 is a perspective view of an exemplary exhaust gas recirculation cooler.

[0036] Figure 3 yes Figure 2 End view of an exemplary exhaust gas recirculation cooler.

[0037] Figure 4 yes Figure 2 -3 is a side cross-sectional view of an exemplary exhaust gas recirculation cooler.

[0038] Figure 5 and Figure 6 yes Figure 2 -4 is an enlarged side cross-sectional view of a portion of an exemplary exhaust gas recirculation cooler.

[0039] Figure 7 yes Figure 2 -6 is a top cross-sectional view of an exemplary exhaust gas recirculation cooler.

[0040] Figure 8 is a perspective view of another exemplary exhaust gas recirculation cooler.

[0041] Fig. 9 yes Figure 8 A perspective cutaway view of an exemplary exhaust gas recirculation cooler.

[0042] Fig.10 yes Figure 8 -9 is a side cross-sectional view of an exemplary exhaust gas recirculation cooler.

[0043] Fig.11 yes Figure 8 -10 is an enlarged perspective cross-sectional view of a fluid diode portion of an exemplary exhaust gas recirculation cooler.

[0044] Fig.12 is a schematic diagram of an exemplary fluidic diode configuration.

[0045] Fig.13 is a flow chart showing an example of a process for cooling recirculated exhaust gas. DETAILED DESCRIPTION

[0046] This document describes systems and techniques for cooling exhaust gas recirculation (EGR) gases that improve EGR efficiency by preventing EGR backflow. Generally, an EGR cooler is configured as a check valve or fluid diode that allows gas flow in the forward direction (e.g., from the exhaust through the EGR cooler toward an engine inlet such as an intake manifold) while blocking gas flow in the reverse direction (e.g., from the intake through the EGR cooler toward the exhaust manifold). By using a fluid diode design that does not require the use of moving mechanical parts, the reliability and service life of the EGR cooler are improved.

[0047] Figure 1 is a schematic diagram of an exemplary engine system 100 . Figure 1 The exemplary engine system 100 shown in FIG. 1 may be a diesel engine with an exhaust gas recirculation (EGR) subsystem, or the exemplary engine system 100 may be another type of engine (e.g., compression ignition, spark ignition). In some cases, the EGR subsystem may reduce the formation of unwanted emissions (e.g., nitrogen oxides, NOx) in the engine system 100. The techniques described herein may be applied to the exemplary engine system 100, or to other types of systems having airflow with flow instabilities.

[0048] The exemplary engine system 100 includes an engine block 102, an intake manifold 104, an exhaust manifold 106, an exhaust gas recirculation (EGR) valve 108, and an EGR cooler 110. The engine system 100 may include additional or different components and subsystems. The components of the engine system 100 may be as follows: Figure 1 Although it can be constructed as in the example shown in , it can also be constructed in another way.

[0049] The intake manifold 104 of the exemplary system 100 receives air from an air intake system. In certain exemplary engine systems, the air intake system may include, for example, a turbocharger compressor, an intake air cooler, an air intake throttle valve, and other components. The intake manifold 104 may also receive exhaust gas from an exhaust manifold 106. An EGR valve 108 may control the flow of exhaust gas into the intake manifold 104.

[0050] The EGR cooler 110 may cool the flow of combustion exhaust gas entering the intake manifold 104. In some cases, no exhaust gas flows into the intake manifold 104. The intake manifold 104 may provide an air mixture to the engine block 102. The air mixture provided to the engine block 102 may include air from the air intake system, which may be mixed with cooled combustion exhaust gas from the exhaust manifold 106 and possibly other fluids. The intake manifold 104 may include various flow meters, valves, sensors, and Figure 1 Other components not specifically shown.

[0051] The engine system 102 may include various features, components, and subsystems. For example, the engine body 102 may include combustion chambers, cylinders, pistons, an ignition system, a fuel injection system, and various other features. The engine body 102 may receive an air mixture from an intake manifold 104 (e.g., via an intake valve), and may receive fuel from a fuel injection system. The ignition system may ignite the air-fuel mixture in the combustion chamber of the engine body 102, thereby causing the piston to move and produce a mechanical output of the engine body 102 (e.g., rotation of a crankshaft, etc.). Exhaust generated by the combustion of the air-fuel mixture in the engine body 102 may be directed (e.g., via an exhaust valve) to an exhaust manifold 106.

[0052] The exhaust manifold 106 receives exhaust from the engine body 102. The exhaust manifold 106 can communicate the exhaust to a component of an exhaust system or another subsystem of the engine system 100. In certain embodiments, the exhaust manifold 106 directs the exhaust through an exhaust turbine of a turbocharger. In these embodiments, the exhaust can be communicated from the turbocharger from the engine system 100 to the external environment, for example. The exhaust manifold 106 can communicate the exhaust through an EGR cooler 110 and an EGR valve 108. The exhaust manifold 106 may include various flow meters, valves, sensors, and Figure 1 Other components not specifically shown.

[0053] The EGR valve 108 controls the flow of exhaust gas from the exhaust manifold 106 to the intake manifold 104. For example, the EGR valve 108 may control the flow by manipulating (eg, opening, closing, constricting, expanding, etc.) an exhaust flow path. Figure 1 In the example shown in FIG. 1 , the EGR valve 108 is located downstream of the EGR manifold branch point. The EGR valve 108 can increase the upstream pressure to allow the exhaust gas to flow back to the intake manifold 104 at a sufficient speed. There may be and usually are more valves in the EGR system. Although these valves are not specifically shown in the exemplary engine system 100, in some cases, there may also be a valve for metering the flow into the intake manifold 104 and an intake throttle valve to further improve the pressure difference from the exhaust manifold 106 to the intake manifold 104.

[0054] The EGR cooler 110 is configured as a heat exchanger device that cools the exhaust gas flow from the exhaust manifold 106 to the intake manifold 104. For example, the EGR cooler 110 may cool the gas flow by transferring heat from the exhaust gas in the exhaust flow path to the coolant in the coolant flow path. Figure 1 In the example shown in FIG. 1 , the EGR cooler 110 is located downstream of the EGR manifold branch point. The EGR cooler 110 can increase the upstream pressure so that the exhaust gas flows back to the intake manifold 104 at a sufficient speed.

[0055] Although not specifically shown in the exemplary engine system 100 , in certain embodiments, there may also be a valve for metering flow into the intake manifold 104 and an intake throttle valve to further improve the pressure differential from the exhaust manifold 106 to the intake manifold 104 .

[0056] In certain embodiments, the exhaust pressure generated by the engine system 100 may exert a force on the EGR valve 108. For example, the EGR valve 108 may include a throttle assembly in fluid communication with an exhaust port of the engine block 102 and an inlet fluid of an exhaust turbine of a turbocharger. For example, the throttle valve may experience severe fluid force fluctuations due to unstable engine exhaust processes in the exhaust manifold 106. In these and other cases, the exhaust gas may exert an unstable aerodynamic torque load on the EGR valve shaft, causing the EGR valve to displace from a desired valve position. In some cases, the unstable load on the EGR valve may cause the valve to repeatedly hit its end-of-travel stop, which may cause mechanical instability or failure of the EGR valve.

[0057] In certain embodiments, the controller may control the operation of the EGR valve 108. In certain examples, the controller may generate an EGR valve control signal configured to achieve a desired EGR valve position. The controller may generate the EGR valve control signal based on data stored in a memory, data received from the EGR valve 108, engine operating state data from sensors installed in the engine system 100, or a combination of these and other data. The controller may send the EGR valve control signal to the EGR valve 108 to control the position of the EGR valve 108.

[0058] In previous designs, the EGR valve is arranged downstream of a previously known EGR cooler, which can significantly suppress useful (e.g., forward-flowing) pulsations. In order to reduce or eliminate valve position disturbances caused by unstable exhaust pressure on the EGR valve 108, while allowing useful pulsations and preventing backflow, the EGR cooler 110 acts as a check valve. For example, the EGR cooler 110 can allow pulsations to flow forward (e.g., away from the exhaust portion and toward the intake portion) substantially unimpeded, and can substantially prevent or block reverse flow.

[0059] Sensors in the engine system 100 may include, for example, pressure sensors, temperature sensors, accelerometers, position sensors, etc. In certain embodiments, one or more pressure sensors in the intake manifold 104 provide data indicating engine load; one or more engine speed sensors in the engine body 102 provide data indicating engine speed (e.g., based on the rotation speed of the crankshaft, etc.); and one or more position sensors in the engine body 102 provide data indicating engine position (e.g., based on the position of the piston, etc.). In certain embodiments, one or more position sensors in the EGR valve 108 provide data indicating the position of the EGR valve shaft or the EGR valve actuator, etc.

[0060] Figure 2is a perspective view of an exemplary exhaust gas recirculation (EGR) cooler 200. In the illustrated example, the EGR cooler 200 is configured as a heat exchanger device. In certain embodiments, the EGR cooler 200 may be Figure 1 1. The exemplary EGR cooler 110 in FIG. The EGR cooler 200 includes an EGR port 202 (e.g., a fluid inlet configured to supply a first fluid to the EGR cooler 200), which is in fluid communication with an EGR port 204 (e.g., a fluid outlet). The EGR cooler 200 has an internal configuration, which will be described in detail below, that provides a check valve or fluid diode function for EGR gas that flows primarily from the EGR port 202 to the EGR port 204.

[0061] The EGR cooler 200 includes a coolant port 206 (e.g., a coolant fluid inlet configured to supply another different fluid to the EGR cooler 200), which is in fluid communication with a coolant port 208 (e.g., a coolant fluid outlet). The EGR cooler 200 has an internal configuration that will be described in more detail below, and functions as a heat exchanger, wherein the heat energy of the EGR gas is transferred to the coolant fluid flow between the coolant port 206 and the coolant port 208 (or the coolant flow between the coolant port 208 and the coolant port 206).

[0062] Figure 3 yes Figure 2 2 is an end view of an exemplary EGR cooler 200 . Figure 4 is along Figure 3 The cross section A-A Figure 2 -3 is a side cross-sectional view of an exemplary EGR cooler 200. EGR cooler 200 includes a fluid diode 400a (e.g., a check valve), a fluid diode 400b, a fluid diode 400c, and a fluid diode 400d. Although the exemplary EGR cooler 200 includes four such fluid diodes, in some examples, more or fewer fluid diodes (e.g., one, two, three, five, ten, twenty) may be used. For example, the EGR cooler 200 may be manufactured in four sections (e.g., by additive manufacturing, 3D printing), each section having six levels of paired fluid diodes. In other examples, other designs and / or manufacturing techniques may also be used. Although in the illustrated examples, fluid diodes 400a-400d are shown as being substantially identical, in some examples, the fluid diodes may be constructed with different and / or varying geometries, and / or different packaging configurations.

[0063] In general, each fluid diode 400a-400d defines a fluid conduit 402 that includes a thermally conductive material and is configured as a Tesla valve having a plurality of at least partial loops 410 having an annular portion 420 (e.g., an eye). As will be described in more detail below, in such a configuration, fluid may flow substantially unimpeded in one fluid flow direction (e.g., from EGR port 202 to EGR port 204), while fluid flow in the opposite fluid flow direction (e.g., from EGR port 204 to EGR port 202) will be split into two or more sub-conduits and redirect the flow toward itself, thereby obstructing and / or substantially preventing reverse flow. The fluid diodes 400a-400d are configured to provide such a two-pole or check valve function without substantially using moving or mechanical parts. In certain embodiments, other types of check valves and / or fluid diodes (e.g., ball check valves, tilting disk valves, swing check valves) may be used.

[0064] The EGR cooler 200 includes a plurality of intercooler units 450 . Figure 5 and Figure 6 is an enlarged side cross-sectional view of an exemplary intercooler unit 450. Figure 5 In the illustrated example of , EGR fluid flow in a first (e.g., forward) direction is indicated by arrow 501. Each loop 410 is configured as a portion of a fluid conduit 402 that defines a curved fluid flow path. Each fluid conduit 402 has a conduit wall 510 made of a thermally conductive material that defines a fluid channel 520 that is formed as a curved segment that defines a corresponding one of the annular portions 420 to define a set of fluid flow paths (as indicated by arrow 502). Each of the annular portions 420 defines another fluid conduit 530 that is fluidically isolated from the fluid conduits defined by the fluid diodes 400a-400d. The fluid stream 501 flows along a series of substantially straight linear flow paths 504 that are connected by a collection of small angle joints 506. Fluid conduit 530 is in thermal communication with fluid conduit 402 such that thermal energy from the EGR gases (or any other suitable fluid) may be transferred through conduit wall 510 to the coolant fluid flowing through annulus 420 (as indicated by arrow 502 ) as coolant flows from one coolant port 206 to the other coolant port 208 .

[0065] exist Figure 6 In the example shown in FIG. 1 , (e.g., based on whether the pressure dynamics between the two ends of the EGR cooler 200 is rising or falling) along with Figure 5The EGR fluid flow in a second direction (e.g., reverse or backward flow) opposite to the first direction is indicated by arrow 601. In the illustrated configuration, fluid flow 601 is repeatedly divided into sub-flow 602a passing through sub-conduit 603a and sub-flow 602b passing through sub-conduit 603b at the collection of branch 605. Sub-flow 602a is redirected through one of fluid channels 520 and rejoins sub-flow 602b at the collection of joint 607. Joint 607 is configured so that sub-flow 602a at least partially flows relative to sub-flow 602b. The flow resistance generated at each joint 607 will generate additional resistance to fluid flow 601, thereby providing a two-polarity function for fluid flows 501 and 601.

[0066] Figure 7 yes Figure 2 6. EGR port 202, EGR port 204, coolant port 206, and coolant port 208 can be seen in this view. EGR cooler 200 includes longitudinal walls 712a and 712b that partially define lateral portions of the housing of EGR cooler 200. Also visible is a cross-sectional view of fluid diode 400a, which includes fluid conduit 530. In the illustrated example, fluid conduit 530 extends only partially between longitudinal wall 712a and longitudinal wall 712b and partially defines longitudinal fluid passage 714a and longitudinal fluid passage 714b between fluid conduit 530, longitudinal wall 712a, and longitudinal wall 712b.

[0067] The EGR cooler 200 includes a set of lateral inner divider walls 710a and a set of lateral inner divider walls 710b. The lateral inner divider walls 710a extend partially from the longitudinal wall 712a to the longitudinal wall 712b, thereby defining a passage 716a between the longitudinal wall 712a and the lateral inner divider walls 710a. The lateral inner divider walls 710b extend partially from the longitudinal wall 712b to the longitudinal wall 712a, thereby defining a passage 716b between the longitudinal wall 712b and the lateral inner divider walls 710b.

[0068] In the illustrated example, coolant fluid flow 701 generally flows from coolant port 206 to coolant port 208. The coolant flows through coolant port 206 into channel 714b and then flows through fluid conduit 530 to longitudinal fluid channel 714a, redirected in part by lateral inner diverter wall 710a. As the coolant flows through fluid conduit 530, it absorbs heat energy from the EGR gas (or other fluid) flowing through fluid diodes 410a-410d through conduit wall 510.

[0069] The coolant flow along the longitudinal fluid passage 714a flows around the lateral inner divider wall 710b through the passage 716a to the next intercooler unit 450. The coolant flows to the longitudinal fluid passage 714a and then flows to the passage 714b through the fluid conduit 530, partially redirected by the lateral inner divider wall 710b. As the coolant flows through the fluid conduit 530, it absorbs additional heat energy from the EGR gas (or other fluid) flowing through the fluid diodes 410a-410d through the conduit wall 510.

[0070] The coolant continues to flow back and forth through the serpentine maze formed by the fluid conduits 530 to the coolant port 208, where the heated coolant exits the EGR cooler 200. In certain embodiments, the heated coolant may be actively and / or passively cooled. For example, the coolant may pass through another heat exchanger (e.g., radiator, geothermal reservoir) to dissipate the thermal energy to the surrounding environment. In another example, the coolant may be processed through a refrigeration cycle that is configured to remove thermal energy from the coolant.

[0071] The design of EGR cooler 200 as shown is one example of various designs that may be implemented. The size, shape, flow direction, flow path, flow pattern and / or other structural details of EGR 200 may be configured based on various target implementations (eg, may be designed for a specific application).

[0072] Figure 8 is a perspective view of an exemplary fluid diode 800 . Fig. 9 yes Figure 8 A perspective cross-sectional view of an exemplary fluid diode 800 is shown. Fig.10 yes Figure 8 -9 is a side cross-sectional view of an exemplary fluid diode 800. In some embodiments, the fluid diode 800 may be Figure 1 For example, the fluid diode 800 may be enclosed in a cooling fluid jacket or immersed in a coolant fluid, and / or a coolant conduit may be defined within the fluid diode 800.

[0073] The fluid diode 800 includes an inlet port 802 configured to receive a fluid (e.g., EGR gas) that is fluidly connected to an outlet port 804. The fluid diode 800 includes three main sections, including an inlet manifold 810 including the inlet port 802, an outlet manifold 812 including the outlet port 804, and a fluid diode portion 820 configured to fluidly connect the inlet manifold 810 to the outlet manifold 812 and define a fluid path therebetween.

[0074] Fig.11 yes Figure 8 An enlarged perspective cross-sectional view of an exemplary fluid diode portion 820 of an exemplary fluid diode 800 of FIG. Fig.11 , the fluid diode portion 820 defines a fluid conduit 830. The fluid conduit 830 is fluidically connected to a fluid conduit 832 defined by the inlet manifold 810, and is fluidically connected to a fluid conduit 834 defined by the outlet manifold 812.

[0075] In general, the fluid diode portion 820 defines the fluid conduit 830 as a Tesla valve having a plurality of loops 840 and a linear section 842. Previously known Tesla valve designs were substantially rectangular in cross-section, wherein the fluid conduit was formed as a rectangular tubular conduit that curved and turned longitudinally and was substantially straight laterally. Unlike such previous designs, the fluid diode portion 820 is substantially a body of revolution, wherein the fluid conduit 830 is formed as a substantially cylindrical cavity defined between a cylindrical outer shell 850 and a cylindrical inner shell 852. The loops 840 are further defined by an annulus 854 disposed between the cylindrical outer shell 850 and the cylindrical inner shell 852.

[0076] The rotary, three-dimensional, cylindrical configuration of fluid conduit 830 can provide performance characteristics that are different from linear and / or rectangular Tesla valve-type fluid diodes. For example, in a rectangular configuration, the flowable cross-sectional area of ​​the loop is substantially equal to the flowable cross-sectional area of ​​the linear portion. In contrast, the flowable cross-sectional area of ​​loop 840 and linear segment 842 is proportional to its predetermined radius / radii. For example, the radially outermost portion of loop 840 has a relatively larger radius, and therefore has a relatively larger flowable area, than the linear segment 842, which has a relatively smaller radius.

[0077] During reverse flow, the flowable area available to the fluid increases as the fluid flows into the outermost portion of loop 840. As the area increases, the fluid velocity decreases. As the fluid flows around loop 840, the flow is redirected radially inward, forcing the fluid into a relatively small area, creating additional obstructive and bipolar back pressure that is not typically found in rectangular designs.

[0078] In this configuration, fluid may flow substantially unimpeded in one direction (e.g., from inlet port 802 to outlet port 804), while fluid flow in the opposite direction (e.g., from outlet port 804 toward inlet port 802) will re-divide and redirect the flow toward itself, thereby obstructing and / or substantially preventing reverse flow. Fluid diode portion 820 is configured to provide this two-pole or check valve function without substantially using moving or mechanical parts.

[0079] Fig.121 is a schematic diagram of an exemplary fluid diode configuration 1200. In general, a bipolar valve (e.g., Figure 1 An exemplary EGR cooler 110 of Figure 2 -7 exemplary EGR cooler 200 and / or Figure 8 The exemplary fluid diode 800 of FIG. 11 is a structure that has a greater pressure drop in the reverse direction than in the forward direction for fluid flow. This difference in flow resistance results in a net directional flow velocity in the forward direction in the oscillating flow. The efficiency of this flow is usually expressed in terms of a dipolar D i , that is, it is expressed as the directional resistance ratio.

[0080] In certain embodiments, the dipolarity can be expressed as:

[0081]

[0082] If D i >1, the catheter has a bipolar characteristic, where:

[0083]

[0084] Where ΔP is the pressure difference between the two ends of the tube and Q is the flow rate. Find D i Inversely proportional to R.

[0085] The performance and characteristics of the Tesla valve-type fluid conduit design can be changed by changing various dimensional parameters (e.g., configuring the design to meet one or more predetermined performance parameters). In the illustrated example, the fluid diode configuration 1200 includes: a linear (e.g., straight) portion 1210 having a predetermined length L 1 and defines a linear fluid flow path; a linear portion 1220 having a length L and defining a linear fluid flow path; a linear portion 1230 having a predetermined length L 2 and defining a linear fluid flow path; a linear portion 1240 having a predetermined width W and defining a linear fluid flow path; and a curved portion 1250 having a predetermined radius R. The linear portion 1240 branches off from the linear portion 1220 at a predetermined angle α, and the curved portion 1250 intersects the linear portion 1240 at a predetermined tangent angle β.

[0086] The relationship between the various dimensions of the fluid diode configuration 1200 can affect the diode properties of the fluid diode configuration 1200. Angle α can be selected between about 10 degrees and about 80 degrees. A larger angle β can reduce the flow entering the curved portion 1250 in the forward flow direction. A larger angle β can increase the resistance or blocking effect of reverse flow through the curved portion 1250.

[0087] Fig.13is a flow chart showing an example of a process 1300 for cooling recirculated exhaust gas. In certain embodiments, the process 1300 may be performed by Figure 1 An exemplary engine system 100 of Figure 1 An exemplary EGR cooler 110 of Figure 2 -7 exemplary EGR cooler 200, Figure 8 -11 exemplary fluid diode 800 and / or Fig.12 The exemplary fluid diode configuration 1200 may be implemented in whole or in part.

[0088] At 1310 , a first fluid flows in a first direction through a first fluid conduit configured as a Tesla valve that defines a first fluid flow path and includes at least one partial loop defining an annular portion. For example, EGR gas may be supplied to fluid port 202 to flow through fluid conduit 402 to fluid port 204 .

[0089] At 1320 , a second fluid different from the first fluid is flowed through a second fluid flow path different from the first fluid flow path and at least partially defined by the annulus. For example, coolant may be provided to fluid port 206 so as to flow through annulus 420 to fluid port 208 .

[0090] In some embodiments, process 1300 may include receiving combustion exhaust gas from an exhaust manifold of an internal combustion engine; providing the combustion exhaust gas as a first fluid; cooling the combustion exhaust gas by transferring heat energy from the combustion exhaust gas to a second fluid; and providing the cooled combustion exhaust gas to an intake manifold of the internal combustion engine. For example, heat energy from the hot EGR gas may be transferred through a wall of fluid conduit 402 to a coolant flowing through annular portion 420.

[0091] In certain embodiments, process 1300 may include flowing the first fluid along a first substantially straight portion of the first fluid flow path through an intersection with the local loop, redirecting the first fluid through a first fluid conduit at a predetermined angle of about 10 degrees to about 80 degrees, and flowing the first fluid along a second substantially straight portion of the first fluid flow path. Figure 5 As discussed in the description of , EGR gas may flow in a forward direction.

[0092] In certain embodiments, process 1300 may include: causing a first fluid to flow through a first fluid flow path in a second direction opposite to the direction of flow of the first fluid; and obstructing fluid flow in the second direction through the fluid flow path. In certain embodiments, causing a first fluid to flow through a first fluid flow path in a second direction opposite to the direction of flow of the first fluid may include: causing a first portion of the first fluid flow to flow along a substantially straight portion of the first fluid flow path; causing a second portion of the first fluid flow to flow along a curved portion of the first fluid flow path toward an intersection of the curved portion and the substantially straight portion; and recombine the first portion of the first fluid flow and the second portion of the first fluid flow proximal to the intersection; and obstructing fluid flow in the second direction through the fluid flow path includes: fluidly interfering with the first fluid flow through the second fluid flow and based on the recombination. For example, as in the case of Figure 6 As discussed in the description of , the EGR gas flowing in the reverse direction can be blocked or prevented.

[0093] In certain embodiments, the substantially straight portion may have a predetermined length L, and the minimum radius of the curved portion may be approximately Wherein, α may be a predetermined angle at the intersection. For example, the fluid diode 200 may be as in Fig.12 Configured as discussed in the description of the exemplary fluid diode configuration 1200.

[0094] Although some embodiments have been described in detail above, other modifications are possible. For example, the logic flow described in the figure does not require the specific order or sequence shown to obtain the desired results. In addition, other steps can be provided from the described process, or these steps can be eliminated, and other components can be added or deleted from the described system. Therefore, other embodiments are within the scope of the following claims.

Claims

1. A heat exchanger device, comprising: a first fluid conduit defining a first fluid flow path for a first fluid and comprising a fluid diode, the fluid diode being at least partially fluid-dipolar and formed of a thermally conductive material, the fluid diode comprising: a first fluid inlet; a first fluid outlet; a first sub-conduit extending from the fluid inlet to the fluid outlet; and a second sub-conduit extending as a local loop from the first sub-conduit proximal to the fluid inlet to the first sub-conduit proximal to the fluid outlet, the local loop defining a lumen extending through the local loop; and A second fluid conduit is in thermal communication with the first fluid conduit and defines a second fluid flow path for a second fluid through the local loop that is fluidly isolated from the first fluid flow path.

2. The heat exchanger device according to claim 1, characterized in that The fluid diode partially defines the second fluid conduit, and the cavity partially defines the second fluid flow path.

3. The heat exchanger device according to claim 1, characterized in that The second fluid conduit is formed from another thermally conductive material and extends through the cavity.

4. The heat exchanger device according to any one of claims 1 to 3, characterized in that: The fluid diode comprises a Tesla valve.

5. The heat exchanger device according to any one of claims 1 to 3, characterized in that: The first sub-conduit defines the first fluid flow path as a substantially linear fluid flow path from the fluid inlet to the fluid outlet.

6. The heat exchanger device according to any one of claims 1 to 3, characterized in that: The second sub-conduit defines the second fluid flow path as a substantially curved fluid flow path having a predetermined radius.

7. The heat exchanger device according to any one of claims 1 to 3, characterized in that: The fluid inlet includes a third sub-conduit defining a first substantially linear fluid flow path; The first sub-conduit defines the first fluid flow path as a second substantially linear fluid flow path disposed at a first predetermined angle to the first substantially linear fluid flow path; and The second sub-conduit comprises: a curved section, the curved section being in fluid communication with the first sub-conduit and extending away from the first sub-conduit at a second predetermined angle to the first sub-conduit; as well as A linear segment is configured to fluidly connect the third sub-conduit and the curved segment, the linear segment defining a third substantially linear fluid flow path substantially aligned with the first substantially linear fluid flow path.

8. The heat exchanger device according to claim 7, characterized in that The linear segment has a predetermined length L; and The minimum radius of the curved section is approximately Wherein, α is the first predetermined angle.

9. The heat exchanger device according to claim 7, characterized in that The first predetermined angle ranges from about 10 degrees to about 80 degrees.

10. The heat exchanger device according to any one of claims 1 to 3, characterized in that: Also includes: a first inlet manifold in fluid communication with the first fluid inlet and configured to supply a first fluid to the first fluid conduit; a second inlet manifold in fluid communication with a second inlet of the second fluid conduit and configured to supply a second fluid to the second fluid conduit; a first outlet manifold in fluid communication with the first fluid outlet; as well as A second outlet manifold is in fluid communication with a second fluid outlet of the second fluid conduit.

11. A heat exchanger device comprising: a first fluid conduit defining a first fluid flow path and configured as a Tesla valve including at least one partial loop defining an annular portion; as well as A second fluid conduit is in thermal communication with the first fluid conduit and defines a second fluid flow path through the annular portion that is different from the first fluid flow path.

12. The heat exchanger device according to claim 11, characterized in that The Tesla valve includes a plurality of local loops that are fluidly interconnected and define the first fluid flow path.

13. The heat exchanger device according to claim 11, characterized in that Also includes: a first inlet manifold configured to supply a first fluid to the first fluid conduit, wherein the first fluid conduit includes another Tesla valve arranged in fluid parallel with the Tesla valve; a first outlet manifold configured to receive the first fluid from the first fluid conduit; a second inlet manifold configured to supply a second fluid to the second fluid conduit, wherein the second fluid conduit includes a plurality of second fluid flow paths through one or more of the plurality of local loops; and A second outlet manifold is configured to receive the second fluid from the second fluid conduit.

14. The heat exchanger device according to any one of claims 11 to 13, characterized in that The first fluid comprises combustion exhaust, and the second fluid comprises a coolant fluid configured to absorb thermal energy transferred from the combustion exhaust.

15. A heat exchange method, comprising: flowing a first fluid in a first direction through a first fluid conduit configured as a Tesla valve defining a first fluid flow path and including at least one partial loop defining an annular portion; and A second fluid different from the first fluid is caused to flow through a second fluid flow path different from the first fluid flow path and at least partially defined by the annular portion.

16. The method according to claim 15, characterized in that Also includes: receiving combustion exhaust gas from an exhaust manifold of an internal combustion engine; providing the combustion exhaust gas as the first fluid; cooling the combustion exhaust by transferring heat energy from the combustion exhaust to the second fluid; and Cooled combustion exhaust gases are provided to an intake manifold of the internal combustion engine.

17. The method according to claim 15 or 16, characterized in that The first fluid conduit for flowing the first fluid in the first direction through the Tesla valve configured to define the first fluid flow path and including at least one partial loop defining an annular portion comprises: flowing the first fluid along a first substantially straight portion of the first fluid flow path through an intersection with the local loop; redirecting the first fluid through the first fluid conduit at a predetermined angle of about 10 degrees to about 80 degrees; and The first fluid is caused to flow along a second substantially straight portion of the first fluid flow path.

18. The method according to claim 15 or 16, characterized in that Also includes: causing the first fluid to flow through the first fluid flow path in a second direction opposite to the first fluid flow direction; as well as Fluid flow in the second direction is obstructed by the fluid flow path.

19. The method according to claim 18, characterized in that: Causing the first fluid to flow through the first fluid flow path in the second direction opposite to the first fluid flow direction includes: causing a first portion of the first fluid flow to flow along a substantially straight portion of the first fluid flow path; directing a second portion of the first fluid flow along a curved portion of the first fluid flow path toward an intersection of the curved portion and the substantially straight portion; and recombine a first portion of the first fluid flow and a second portion of the first fluid flow proximate the intersection; and Impeding fluid flow in the second direction via the fluid flow path includes fluidly disrupting the first fluid flow via the second fluid flow and based on the recombination.

20. The method according to claim 19, characterized in that: The substantially straight portion has a predetermined length L; and The minimum radius of the curved portion is approximately Wherein, α is a predetermined angle at the intersection point.

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