SYSTEMS AND METHODS WITH IMPROVED LR-EGR ACTIVATION

Abstract

Exhaust gas recirculation system (300, 390) for an internal combustion engine (102), comprising: a first line (302) configured to receive at least a section of the exhaust gas from the internal combustion engine (102); a cooling circuit (320) which is selectively fluidically connected to the first line (302); a bypass circuit (330, 430) which is selectively fluidically connected to the first line (302) and includes a bypass line (332, 432); a control valve (310) connected to the first line (302), the cooling circuit (320), and the bypass circuit (330, 430), wherein the control valve (310) has at least one bypass position to allow the exhaust gases from the first line (302) to pass through the bypass circuit (330, 430), a cooling position to allow the exhaust gases from the first line (302) to pass through the cooling circuit (320), and a closed position to prevent the exhaust gases from flowing out of both the bypass circuit (330, 430) and the cooling circuit (320); a heating device (334, 434) which is connected to a wall of the bypass line (332, 432) for selective heating of the bypass line (332, 432); a second line (304) which is fluidically connected to receive the exhaust gas flowing through the cooling circuit (320) and through the bypass circuit (330, 430), wherein the second line (304) is fluidically connected to return the exhaust gas to the combustion engine (102); a control unit (500) connected to the control valve (310) and to the heating device (334, 434), wherein the control unit (500) is configured to selectively direct the control valve (310) to the bypass, cooling, and closed positions, and to control the heating device (334, 434), wherein the control unit (500) is configured to determine a wall temperature of the bypass line (332, 432) associated with the wall of the bypass line (332, 432) and a cooling temperature associated with the coolant in the cooling circuit (320), and to selectively direct the control valve (310) based on the wall temperature of the bypass line (332, 432) and the coolant temperature wherein the control unit (500) is further configured to determine a dew point temperature associated with an environment and to selectively instruct the control valve (310) based additionally on the dew point temperature, wherein the control unit (500) is configured to instruct the control valve (310) to move to the closed position when the wall temperature of the bypass line (332, 432) is lower than the dew point temperature, and wherein the control unit (500) is configured to activate the heating device (334, 434) when the wall temperature of the bypass line (332, 432) is less than the dew point temperature.

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to an internal combustion engine, typically an internal combustion engine of a motor vehicle, and relates in particular to exhaust gas recirculation systems for internal combustion engines. BACKGROUND

[0002] Internal combustion engines can burn a mixture of air and fuel within one or more combustion chambers, producing exhaust gases. Some vehicle systems may include an exhaust gas recirculation system configured to return a portion of the exhaust gases to the combustion engine, thus providing the potential for reduced emissions.

[0003] Accordingly, it is desirable to provide improved exhaust gas recirculation systems, including systems that can be activated to operate over a wide range of conditions. Furthermore, other desirable functions and features of the present invention will become apparent from the following detailed description and the attached claims in conjunction with the attached drawings, as well as the preceding technical field and background.

[0004] JP H11- 117 815 A shows an exhaust gas recirculation system by which NOx and exhaust particles in the exhaust gas are reduced by providing a means of changing the temperature of the recirculated exhaust gas (EGR gas) depending on the operating state of an engine.

[0005] DE 10 2005 041 149 A1 discloses a heat exchanger valve device for controlling a fluid flow, in particular an exhaust gas or charge air flow, with a valve housing that has an inlet for the fluid flow and a heat exchanger outlet through which a more or less large fluid flow is supplied to a heat exchanger, in particular a cooler, depending on the position of a valve body.

[0006] JP 2010-48107A shows a bypass channel on an EGR cooler installed in an EGR duct, and the flow rate of the EGR gas flowing to the side of the EGR cooler and to the side of the bypass channel can be adjusted by a control valve. A heater is provided on the bypass channel, and the EGR gas flowing in the bypass channel can be heated.

[0007] DE 10 2016 200 222 A1 discloses an exhaust gas recirculation system for directing exhaust gas from an exhaust tract into an intake tract of a motor vehicle, which has at least one inlet channel, one outlet channel, one cooler channel with a cooler device, one bypass channel, one exhaust gas recirculation valve and one bypass valve, and in which at least one part of the channels has a device on the outside for receiving a fluid medium. SUMMARY

[0008] An exhaust gas recirculation (EGR) system is provided for an internal combustion engine. The system includes a first line configured to receive at least a portion of the exhaust gas from the engine; a cooling circuit selectively connected to the first line; a bypass circuit selectively fluidically connected to the first line and including a bypass circuit; and a control valve connected to the first line, the cooling circuit, and the bypass circuit. The cooling valve has at least one bypass position to route exhaust gases from the first line through the bypass circuit, a cooling position to route exhaust gases from the first line through the cooling circuit, and a closed position to prevent exhaust gases from flowing from both the bypass circuit and the cooling circuit.The system also includes a heating device connected to the bypass circuit to selectively heat it, and a second, fluidically connected line to collect the exhaust gases flowing through the cooling circuit and the bypass circuit. This second line is fluidically connected to return the exhaust gases to the combustion engine.

[0009] A method for operating an exhaust gas recirculation system for a separation engine is provided. The exhaust gas recirculation system includes a bypass circuit and a cooling circuit. The method involves determining a bypass line wall temperature associated with a bypass line of the bypass circuit; comparing the bypass line wall temperature with a dew point temperature; heating a bypass line wall using a heating device when the bypass line wall temperature is lower than the dew point temperature; and positioning a control valve in a bypass position so that exhaust gases are recirculated through the bypass circuit when the bypass line wall temperature reaches or exceeds the dew point temperature. DESCRIPTION OF THE DRAWINGS

[0010] The exemplary embodiments are described below in conjunction with the following drawings, in which the same numbers denote the same elements. Fig. Figure 1 is a schematic view of an automotive system according to an exemplary embodiment; Fig. 2 is section AA of an internal combustion engine of the automotive system of Fig. 1; Fig. Figure 3 is an isometric view of a section of a bypass line of an EGR system of an automotive system. Fig. 1 according to an exemplary embodiment. Fig. Figure 4 is an isometric view of a section of a bypass line of an EGR system of an automotive system according to a further exemplary embodiment. Fig. 5 is a schematic block diagram of an EGR control unit of the automotive system. Fig. 1 according to an exemplary embodiment; and Fig. Figure 6 is a flowchart of a method for operating an EGR system according to an exemplary embodiment. DETAILED DESCRIPTION

[0011] The following detailed description is merely exemplary and is not intended to limit the invention or the application and uses of the invention disclosed herein. Furthermore, there is no intention to be bound by any theory expressly or implicitly presented in the preceding technical field, background, summary, or the following detailed description; it is expressly reproduced as a claimed subject matter.

[0012] Some embodiments can be an automotive system 100, as in the Fig. 1 and Fig. Figure 2 shows a combustion engine 102. It is understood that the engine 102 and various aspects of the overall system 100 are merely exemplary, and that the embodiments described herein can be implemented in various engine systems.

[0013] In the illustrated embodiment, the engine 102 comprises an engine block 110 defining at least one cylinder 112, which has a piston 114 connected to rotate a crankshaft 116. A cylinder head 118, together with the piston 114, forms a combustion chamber 120. A fuel / air mixture (not shown) is introduced into the combustion chamber 120 and ignited, resulting in a reciprocating motion of the piston 114 due to the expanding hot exhaust gases. Air is supplied through at least one intake port 124, and fuel is supplied via at least one injector 122 from a fuel distribution pipe 126, which is fluidically connected to a high-pressure fuel pump 128 and a fuel source 130. Each of the cylinders 112 has at least two valves 132, which are actuated by a camshaft 134 that rotates in sync with the crankshaft 116.The valves 132 selectively allow air from the channel 124 into the combustion chamber 120. In some examples, a camshaft adjuster 136 can selectively vary the timing between the camshaft 134 and the crankshaft 116.

[0014] Air can be transported through an intake manifold 124 to the intake port(s) 138. An intake port 140 can direct ambient air to the intake manifold 138. In one embodiment, the intake port 140 can include a filter 144 for filtering the incoming air, and a throttle body 142 can also be provided to regulate the airflow into the intake manifold 138. After combustion, the exhaust gas flows from the exhaust ports 146 through an exhaust manifold 222.

[0015] In some embodiments, a turbocharger 200 or another type of forced air system may be provided to improve emissions and / or efficiency. The turbocharger 200 may include a compressor 210, which is rotatably connected to a turbine 220. For example, air from the inlet duct 140 may flow to an inlet duct 230 of the turbocharger and into the compressor 210. The compressor 210 increases the pressure and temperature of the air and then directs the air through an outlet duct 232 of the turbocharger to the intake manifold 138. An intercooler 234 may be arranged in the outlet duct 232 of the turbocharger to reduce the temperature of the air before it enters the intake manifold 138. The turbine 220 is connected to the exhaust manifold 222 of the engine 102 and rotates by drawing in the exhaust gases from the exhaust manifold 222. This example from Fig. Figure 1 shows a variable geometry turbine (VGT) with a VGT actuator 224 arranged to move the vanes to change the exhaust gas flow through the turbine 220. In other embodiments, the turbocharger 200 can have a fixed geometry and / or include an exhaust duct. After leaving the turbine 220, the exhaust gases are directed to an aftertreatment system 240.

[0016] The aftertreatment system 240 can include an exhaust pipe 242 with one or more aftertreatment devices configured to modify the composition of the exhaust gas. Some examples of aftertreatment devices for the aftertreatment system 240 include, but are not limited to, catalytic converters (two-way and three-way), oxidation catalysts, and lean NOₓ converters. xTraps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters, such as selective catalytic reduction at the filter (SCRF), are used. For example, the aftertreatment devices of the aftertreatment system 240 can include a diesel oxidation catalyst (DOC) 244 for decomposing the remaining hydrocarbons (HC) and carbon oxides (CO) contained in the exhaust gas and a diesel particulate filter (DPS) 246 for capturing and removing the diesel particulate material from the exhaust gas. The aftertreatment devices of the aftertreatment system 240 can further include system components for selective catalytic reduction (SCR), such as an SCR catalyst 248 arranged in the exhaust pipe downstream of the DPS 246, and an injector 252 for diesel exhaust fluid (DEF) arranged on the exhaust pipe 242 between the DPS 246 and the SCR catalyst 248.The DEF injector 252 is provided for injecting DEF into the exhaust pipe 242, which mixes with the exhaust gas and is thus transformed into a gaseous reducing agent.

[0017] One or more exhaust gas recirculation (EGR) systems 300, 390 can be provided to reduce nitrogen oxide (NOx) emissions in the automotive system 100 by recirculating exhaust gas into the engine 102. Generally, the EGR systems 300, 390 can include a long-range (LR) (or low-pressure) EGR system 300 and a short-range (SR) EGR system 390, although the SR EGR system 390 may be omitted in some embodiments. The EGR systems 300, 390 are introduced below before a detailed description of their operation.

[0018] The LR-EGR system 300 recirculates a portion of the exhaust gas back into the turbocharger 200 and thus back into the engine 102. In this embodiment, the LR-EGR system 300 can include an upstream line 302 of the LR-EGR extending from the exhaust pipe 242. More precisely, the upstream line 302 of the LR-EGR branches off from a section of the exhaust pipe 242 located downstream of the turbine 220. In the illustrated example, the upstream line 302 branches off from the exhaust pipe 242 at a downstream position of the DPF 246 and an upstream position of the DEF injector 252.

[0019] A downstream line 304 of the LR-AGR system 300 is fluidically connected to the intake port 230 to return the exhaust gases from the LR-AGR system 300 to the compressor 210 of the turbocharger 200. In this example, the downstream line of the LR-AGR 304 is connected to a section of the intake port 230 between the air filter 144 and the compressor 210. An intake valve 306, which can be positioned at the connection between the downstream line 304 of the LR-AGR and the intake port 230, can allow the control of the flow of ambient air into the intake port 230 and / or the exhaust gas into the LR-AGR system 300.

[0020] The upstream line 302 and the downstream line 304 of the LR-EGR system 300 are fluidically coupled to each other via a cooling circuit 320 or a bypass circuit 330. In other words, during operation of the LR-EGR system 300, the exhaust gas flows selectively from the exhaust pipe 242 through the cooling circuit 320 or the bypass circuit 330, through the upstream line 302, and through the downstream line 304 to the intake port 230. An EGR control valve 310 is provided for control via the cooling circuit 320 and the bypass circuit 330, as well as in the upstream line 302. As described in more detail below, the EGR control valve 310 can have three positions or modes. In a first (or closed) position, the EGR control valve 310 prevents exhaust gas from flowing through the LR-EGR system 300. In a second (or normal) position, the exhaust gas flows through a cooling circuit 320, but not through the bypass circuit 330.In a third (or bypass) position, the exhaust gas flows through a bypass circuit 330, but not through the cooling circuit 320.

[0021] In general, the cooling circuit 320 includes a cooling channel 322 extending between the upstream line 302 and the downstream line 304. The cooling circuit 320 further includes a cooling arrangement 324, the function of which is to cool the exhaust gas flowing through the cooling channel 322 before it is recirculated to the turbocharger 200 and the engine 102. For example, the cooling arrangement 324 includes a heat exchanger 326 with coolant flowing through it (e.g., water, antifreeze, or a mixture thereof), which extracts heat from the exhaust gas. The coolant flowing through the heat exchanger 326 can be cooled by a cooling device 328, which is in fluidic communication with the heat exchanger 326. In an exemplary embodiment, the cooling device 328 and the heat exchanger 326 can be part of a larger cooling system, e.g.,a cooling system that serves other sections of the automotive system 100 and / or the vehicle. For example, the cooling device 328 can also be a heat exchanger, such as a radiator, that exchanges the heat removed from the exhaust gas with ambient air. Furthermore, although not shown, additional components, such as vanes and pumps, can be provided.

[0022] In general, the bypass circuit 330 includes a bypass line 332 that extends between the upstream line 302 and the downstream line 304.

[0023] The bypass circuit 330 also includes a heating device 334, the function of which is to raise the temperature of the walls of the bypass line 332. Further details regarding the heating device 334 are provided below.

[0024] There will be brief reference to Fig. Figure 3, which is an isometric partial view of a section of the bypass circuit 330 according to an exemplary embodiment. The in Fig. Section 3 shown includes, in particular, the heating device 334 in the form of a heating element embedded in the wall of the bypass line 332 or otherwise connected to it. As an example, the heating device 334 is an elongated element wound spirally around the wall of the bypass line 332. Upon activation, the heating device 334 applies heat to raise the temperature of the wall of the bypass line 332. In one embodiment, the heating element can be a resistance element (e.g., implementing Joule heating), although other heating arrangements can be provided.

[0025] In some embodiments, the bypass line 332 can be represented as a double-walled line with a further outer wall 340 (shown in dashed lines) surrounding an inner wall 342, forming a flow path for the exhaust gas, thus creating an air gap between the outer and inner walls 340, 342. In this embodiment, the heating device 334 can be provided on the inner wall 342 to increase the temperature of the wall in contact with the exhaust gas after activation. In one embodiment, the inner wall 342 can be relatively thin to allow for faster heating, and the outer wall 340 can be relatively thick, for example, to meet structural requirements or functionalities. As such, in one embodiment, the outer wall 340 can be thicker than the inner wall 342.

[0026] There will be brief reference to Fig. Figure 4 shows an isometric partial view of a section of a bypass circuit 430, which is an alternative to the one in Fig. The arrangement shown in section 3 may be used. As mentioned above, a bypass line 432 (e.g., similar to bypass line 332) is possible. Fig. 3) configured for a flow path for the exhaust gas. In this embodiment, a heating device 434 is arranged on the line 432 in a grid structure to heat the wall of the line 432. Although not shown, the line 432 can, as described above, have a double-walled construction, wherein the illustrated bypass line 432 forms an inner wall enclosed by an additional outer wall. As such, the bypass circuit 330 can be made of Fig. 1 with the arrangements from Fig. 3 or Fig. 4 can be implemented, although other heating arrangements and lines may be provided in other embodiments.

[0027] Returning to Fig. 1. As mentioned above, the LR-EGR system 300 can be operated to recirculate exhaust gas from the exhaust pipe 242 into the engine 102. Under normal conditions, the EGR control valve 310 directs air through the cooling circuit 320 to cool the relatively hot exhaust gas before it enters the turbocharger 200 and / or the engine 102. Under certain conditions, the operation of the LR-EGR system 300 may not be ideal or desirable. At cold ambient temperatures, the walls of the cooling line 322 and / or the bypass line 332 may be cold and are generally colder than the exhaust gas temperature. Similarly, the coolant circulating through the cooling circuit 320 may be cold. A combination of cold wall or coolant temperatures and moist exhaust gas can lead to the formation of liquid condensation, and condensation can cause a number of undesirable problems, particularly regarding the service life of the compressor 210 of the turbocharger 200.

[0028] In conventional LR-EGR systems, the control system can delay the activation of LR-EGR until the coolant temperature rises to a dew point temperature. However, in the exemplary embodiments described herein, the operation of the LR-EGR system 300 can advantageously be modified to provide operation of the LR-EGR system 300 over a wider range of conditions and to avoid or mitigate problems such as condensation. Additional details regarding the operation of the EGR control valve 310, the cooling arrangement 324, and the heating device 334 are provided below.

[0029] The SR-EGR system 390 includes a line 392 to route exhaust gas from the exhaust manifold 222 to the intake manifold 138, although other coupling positions can also be provided. Although not shown, various valves, coolers, sensors, and the like can be provided for operating the SR-EGR system 390.

[0030] The automotive system 100 may also include an electronic control unit (ECU) 450, which communicates with one or more sensors and / or devices associated with the engine 102 and other components of the automotive system. Communication between the electronic control unit 450 and the various sensors and devices is represented by dashed lines in Fig. Figure 1 shows some of the sensors, although some are omitted for clarity. In general, the ECU 450 can receive input signals from various sensors configured to generate signals related to different physical parameters of the engine. These sensors include, without limitation, an air mass and temperature sensor 260, a manifold pressure and temperature sensor 262, a combustion chamber pressure sensor 264, a coolant and oil level and temperature sensor 266, a fuel rail pressure sensor 268, a camshaft sensor 270, a crankshaft sensor 272, an exhaust pressure sensor 274, an EGR bypass temperature sensor 276, an EGR coolant temperature sensor 278, and an accelerator pedal position sensor 280.Furthermore, the ECU 450 can generate output signals for various control units whose function is to control the operation of the engine 102, including, but not limited to, the fuel injectors 122, the throttle body 142, the intake valve 306, the VGT actuator 224, and the camshaft adjuster 136. Additional output signals can be generated by the ECU 450, in particular output signals assigned to the LR-EGR system 300. In one embodiment, the EGR control unit 500 can be implemented by the ECU 450 to control the operation of the LR-EGR system 300, as will be described in more detail below. In this context, the ECU 450 and / or, more specifically, the EGR control unit 500 can generate output signals assigned to the EGR control valve 310, the heating device 334, and / or the cooling arrangement 324.

[0031] In general, the ECU 450 can include a digital data processing unit connected to a storage system, such as data source 460, and an interface bus. The processing unit is designed to execute the instructions stored as a program in the storage system and to send and receive signals via the interface bus. The storage system can have various types of storage, including optical storage, magnetic storage, solid-state storage, and other permanent storage. The interface bus can be designed to modulate analog and / or digital signals and send them to, or receive them from, the various sensors and control units. The program can embody the methods disclosed herein, enabling the processing unit to execute the steps of these methods and control the automotive system 100.

[0032] The program stored in the storage system can be transmitted externally via cable or wirelessly. In some cases, the program can be embodied as a computer program product, also known in technical terms as a computer-readable medium or machine-readable medium, which is understood as computer program code residing on a carrier, where this carrier is either volatile or non-volatile, with the consequence that the computer program product can be considered volatile or non-volatile. An example of a transitory computer program product is a signal, such as an electromagnetic signal like an optical signal, which serves as a transitory carrier for the computer program code.Carrying such computer program code can be achieved by modulating the signal using a conventional modulation technique, such as QPSK for digital data, so that binary data representing the computer program code is imprinted onto the transient electromagnetic signal. Such signals are used, for example, in the wireless transmission of computer program code to a laptop via a Wi-Fi connection. In the case of a non-transient computer program product, the computer program code is embodied in a physical storage medium. The storage medium is then the aforementioned non-transient carrier, so that the computer program code is stored permanently or non-permanently in or on this storage medium. The storage medium can be of a conventional type, as known in computer technology, such as flash memory, an ASIC, a CD, or the like.The ECU 450 can be embodied in any suitable form to provide the electronic logic, e.g., an embedded controller, an on-board computer, or any processing module that can be used in the vehicle.

[0033] As described above, an EGR control unit 500 can be implemented by the ECU 450 to control the operation of the LR-EGR system 300. As such, the EGR control unit 500 can be considered part of the EGR system 300, 390, and in particular the LR-EGR system 300.

[0034] Fig. Figure 5 is a functional block diagram of the EGR control unit 500 with data streams illustrating various operational aspects of the LR EGR system 300. The EGR control unit 500 can be considered to implement one or more functional subunits or modules, including an initiation module 510, a bypass module 520, and a cooling module 530. As can be seen, the in Fig. The 5 modules 510, 520, 530 shown can be combined and / or further subdivided to be operated in a similar manner according to the functions described herein. Fig. 5 is referred to Fig. 1 described.

[0035] In general, the operational monitoring module 510 functions to control the start or initiation of operation of the LR-EGR system 300, which can be initiated in any suitable condition, particularly in the situations described below. In one embodiment, the operational monitoring module 510 can initiate operation based on input data 502, and furthermore, the operational monitoring module 510 can also receive a signal 504 indicating the coolant temperature (T). KÜHLUNG ), which is assigned to the cooling device 328 of the cooling circuit 320. In response, the operational monitoring module 510 can measure the coolant temperature (T KÜHLUNG ) compare with a temperature threshold (T0).

[0036] In an exemplary embodiment, the temperature threshold (T0) is a dew point temperature (T dp) within the LR-AGR system 300. In one embodiment, the dew point temperature (T) can be dp ) based on suitable parameters, such as temperature and pressure, as examples. As such, the temperature threshold (T0) can be stored and / or calculated by a corresponding module (e.g., module 510, discussed above, or module 520, discussed below).

[0037] If the coolant temperature (T KÜHLUNG ) if the temperature threshold (T0) is reached or exceeded, the operational monitoring module 510 can generate a normal operating signal 512, which is provided to the cooling module 530 and is discussed in more detail below.

[0038] Otherwise, if the coolant temperature (T KÜHLUNGIf the EGR temperature is less than the temperature limit (T0), the operational monitoring module 510 can generate a closed EGR valve signal 514 and an activated bypass heater signal 516. The closed EGR valve signal 514 and the activated bypass heater signal 516 can be output by the EGR control unit 500 (e.g., the ECU 450) to the associated component to perform the desired function. In this example, the closed EGR valve signal 514 is provided to the EGR control valve 310 to move or maintain the EGR valve in a closed position. Because the exhaust gas is not recirculated through the LR-EGR circuit, the LR-EGR system 300 is not subject to condensation problems.The signal from the switched-on bypass heating 516 is provided to the EGR bypass heating device 334, so that the heating device 334 is activated and begins to heat a section of the bypass line 332.

[0039] If the coolant temperature (T KÜHLUNG If the wall temperature (T0) is less than the temperature limit value, the operational monitoring module 510 generates a wall monitoring signal 518 for the bypass module 520. After receiving the wall monitoring signal 518, the bypass module 520 begins to monitor the wall temperature (T0). WAND ) and receive and / or evaluate the temperature threshold (T0). As mentioned above, the wall temperature (T) can be WAND ) is collected by the bypass temperature sensor 276 and generally corresponds to the temperature of the walls of the bypass line 332 with which the exhaust gas comes into contact. In some embodiments, the wall temperature (T) can be WAND) based, for example, on the ambient temperature and / or the time elapsed since the heating device 334 was activated.

[0040] As such, the bypass module 520 evaluates the wall temperature (T WAND ) with regard to the temperature threshold (T0). Typically, the dew point temperature in cold weather is initially higher than the wall temperature of the bypass line 332. Under these conditions, the bypass module 520 does not act and the EGR control valve 310 remains closed. However, since the heating device 334 is operated (e.g., as a result of the signal from the activated bypass heating 516 generated by the operational monitoring module 510) to heat the bypass line 332, the wall temperature (T0) rises. WAND ). The bypass module 520 operates by monitoring the wall temperature (T WAND) and when the wall temperature exceeds the temperature threshold (T0), the bypass module 520 generates a signal from the open bypass valve 522, a signal from the deactivated bypass heater 524, and a coolant monitoring signal 526. The signal from the open bypass valve 522 is provided to actuate the EGR control valve 310 in the second or bypass position. As a result of this valve position, the LR-EGR system 300 is operated to recirculate the exhaust gas back into the engine 102 via the bypass circuit 330. The signal from the deactivated bypass heater 524 is provided to deactivate the heater 334. Generally, the wall temperature of the bypass line 332 at this point is high enough that condensation does not occur. Furthermore, due to the exhaust gas temperatures, the walls of the bypass line 332 maintain a temperature above the dew point temperature at this point, even without the heat provided by the heating device 334.

[0041] In fact, the operation of the bypass module 520 enables the activation and use of the LR-EGR system 300 with the bypass circuit 330 in a manner that is independent of the coolant temperature.

[0042] The cooling module 530 receives the coolant monitoring signal 526. After receiving this signal, the cooling module 530 can also receive signals 504 relating to the coolant temperature (T). KÜHLUNG ) are assigned and the coolant temperature (T KÜHLUNG ) compare with the temperature threshold (T0). If the coolant temperature (T KÜHLUNGWhen a temperature threshold (T0) is reached or exceeded, the cooling module 530 generates a signal for the open coolant valve 532. The signal from the open coolant valve 532 is used to actuate the EGR control valve 310 in the cooling position. As a result of this valve position, the bypass line 332 is closed, and the exhaust gas flows through the cooling line 322, thus operating the LR-EGR system 300 to recirculate the cooled exhaust gas back into the engine 102. During further operation, the EGR control module 500 can detect conditions (e.g., the coolant temperature (T0)). KÜHLUNG ) and / or the wall temperature (T WAND )) monitor in order to modify the operation of the LR-AGR system 300, including the operation as described above.

[0043] As mentioned above, the cooling module 530 can receive the normal operating signal 512 from the operational monitoring module 510. In one embodiment, the temperature threshold (T0) of the operational monitoring module 510 can be the same as the coolant temperature (T0). KÜHLUNG ) of the cooling module 530, so that the cooling module 530 can in fact immediately generate the signal of the open coolant valve 532 and the operational signals 534.

[0044] Fig. Figure 6 is a flowchart of a method 600 for operating an EGR system according to an exemplary embodiment. The method 600 from Fig. 6 can be used as an example within the automotive system 100 from Fig. 1 through the EGR control unit 500 from Fig. 5 will be implemented. As such, reference is made to the Fig. 1 and Fig. Reference is made below to 5 in the discussion of procedure 600.

[0045] The various tasks performed in conjunction with Method 600 can be carried out by software, hardware, firmware, or any combination thereof. For illustration, the following description of Method 600 may refer to the tasks described above in conjunction with the Fig. refer to the elements mentioned in points 1-5. It should be noted that Procedure 600 can include any number of additional or alternative tasks, and that the elements mentioned in Fig. The tasks shown in section 6 do not need to be performed in the order shown, and procedure 600 can be integrated into a more comprehensive procedure or a method with additional functionality that is not described in detail here. Furthermore, one or more of the tasks shown in section 6 may be performed in the following order: Fig. The 6 tasks shown in one embodiment of method 600 may be omitted as long as the intended overall functionality remains intact.

[0046] In a first step 605, the EGR control unit 500 initiates operation. In step 605, the EGR control valve is typically in the closed position and the LR-EGR system 300 does not recirculate exhaust gas back to the engine 102.

[0047] In step 610, the EGR control unit 500 begins receiving and / or determining one or more parameters or signals, including a coolant temperature (T). KÜHLUNG ), a wall temperature (T WAND ) for bypass line 332, and other input data that can be used to determine the parameters described below.

[0048] In step 615, the EGR control unit 500 compares the coolant temperature (T KÜHLUNG ) with a temperature threshold (T0) which, as discussed above, is the dew point temperature (T dp ) in the exemplary embodiments. If the coolant temperature (T KÜHLUNGIf the temperature threshold (T0) is reached or exceeded, procedure 600 proceeds to step 650, which is described in more detail below. If the coolant temperature (T KÜHLUNG If the temperature is less than the temperature limit (T0), the process proceeds to step 620 (600). In some embodiments, step 615 may be omitted.

[0049] In step 620, the EGR control unit 500 generates a signal from the closed EGR valve to close the EGR control valve 310. In this position, the EGR control valve 310 prevents exhaust gases from being recirculated through the LR-EGR system 300.

[0050] In step 625, the EGR control unit 500 generates a signal to activate the bypass heater 334. As a result, the heater 334 begins to heat the wall of the bypass line 332.

[0051] In step 630, the EGR control unit 500 evaluates the wall temperature (T WAND) for bypass line 332 with regard to the temperature threshold (T0). If the wall temperature (T WAND If the wall temperature (T0) is less than the temperature limit, the EGR control unit 500 continues monitoring until the conditions change. WAND If the temperature threshold (T0) is met or exceeded, the process 600 proceeds to step 635. In some embodiments, steps 610, 615, 620, 625 and 630 can be considered an initialization mode for the operation of the LR-EGR system 300.

[0052] In step 635, the EGR control unit 500 generates a signal to set the EGR control valve 310 to the bypass position. In this position, the LR-EGR system 300 recirculates the exhaust gas through the bypass circuit 330, and the cooling circuit 320 remains closed. In step 640, the EGR control unit 500 can also generate a signal to deactivate the heating device 334.

[0053] In step 645, the EGR control unit 500 evaluates the coolant temperature (T KÜHLUNG ) with regard to the temperature threshold (T0) again. If the coolant temperature is lower than the specified temperature, the control unit 500 monitors the coolant temperature (T). KÜHLUNG ) continues with respect to the temperature threshold (T0) until conditions change. If the coolant temperature (T KÜHLUNG If the temperature threshold (T0) is met or exceeded, the process 600 proceeds to step 650. In some embodiments, steps 635, 640, and 645 can be considered a bypass mode of operation for the LR-EGR system 300.

[0054] In step 650, the EGR control unit 500 generates a signal to set the EGR control valve 310 to the cooling position. In this position, the LR-EGR system 300 recirculates the exhaust gas through the cooling circuit 320, and the bypass circuit 330 remains closed. In step 655, the EGR control unit 500 can further generate operational signals to operate the LR-EGR system 300 in normal operation. In some embodiments, steps 650 and 655 can be considered normal operation for the LR-EGR system 300. The process 600 can then return to step 605, in which the EGR control unit 500 continues to adjust the conditions with respect to the coolant temperature (Tr). KÜHLUNG ) and / or the wall temperature (T WAND ) to monitor and, if necessary, modifies the operation of the LR-AGR system 300.

[0055] Accordingly, exemplary embodiments can provide for the operation of the LR-AGR systems under a wider range of conditions. In particular, the exemplary embodiment can enable the operation of the LR-AGR system during relatively cold conditions while simultaneously avoiding or mitigating condensation problems.

[0056] The term "module" as used here refers to an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group processor) and memory that executes one or more software or firmware programs, a combinational logic circuit and / or other suitable components that provide the described functionality.

[0057] Exemplary embodiments are provided to ensure that this disclosure is thorough and conveys its scope to those skilled in the art. Details may be provided, such as examples of specific components, devices, and methods, to provide a deep understanding of the embodiments of this disclosure. Skilled in the art will recognize that specific details may not be necessary, that exemplary embodiments can take many different forms, and that none of the embodiments is intended to limit the scope of the disclosure. In some exemplary embodiments, it is possible that well-known methods, well-known device structures, and well-known technologies will not be described in detail.

[0058] The terminology used here serves solely to describe specific exemplary embodiments and is in no way intended to be restrictive. The singular forms used here, e.g., "a," "the," "a," "a," "a," "a," "a," "a," "a," "a," "a," and "has" are non-exclusive and therefore indicate the presence of the specified functions, whole units, steps, processes, elements, and / or components, but do not preclude the presence or addition of further functions, whole units, steps, processes, elements, components, and / or groups thereof. The procedural steps, processes, and operations described here are not to be interpreted in such a way that the described or depicted sequence is absolutely necessary, unless specifically stated as the order of execution.It should also be noted that additional or alternative steps may be applied.

[0059] While at least one exemplary embodiment has been presented in the foregoing detailed description, it is understood that a large number of variants exist. It is further understood that the exemplary embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description provides those skilled in the field with a suitable plan for implementing the exemplary embodiment or embodiments. It is understood that various modifications to the function and arrangement of elements can be made without deviating from the scope of the disclosure as set forth in the appended claims and their legal equivalents.

Claims

[1] Exhaust gas recirculation system (300, 390) for an internal combustion engine (102), comprising: a first line (302) configured to receive at least a section of the exhaust gas from the internal combustion engine (102); a cooling circuit (320) which is selectively fluidically connected to the first line (302); a bypass circuit (330, 430) which is selectively fluidically connected to the first line (302) and includes a bypass line (332, 432); a control valve (310) connected to the first line (302), the cooling circuit (320), and the bypass circuit (330, 430), wherein the control valve (310) has at least one bypass position to allow the exhaust gases from the first line (302) to pass through the bypass circuit (330, 430), a cooling position to allow the exhaust gases from the first line (302) to pass through the cooling circuit (320), and a closed position to prevent the exhaust gases from flowing out of both the bypass circuit (330, 430) and the cooling circuit (320); a heating device (334, 434) which is connected to a wall of the bypass line (332, 432) for selective heating of the bypass line (332, 432); a second line (304) which is fluidically connected to receive the exhaust gas flowing through the cooling circuit (320) and through the bypass circuit (330, 430), wherein the second line (304) is fluidically connected to return the exhaust gas to the combustion engine (102); a control unit (500) connected to the control valve (310) and to the heating device (334, 434), wherein the control unit (500) is configured to selectively direct the control valve (310) to the bypass, cooling, and closed positions, and to control the heating device (334, 434), wherein the control unit (500) is configured to determine a wall temperature of the bypass line (332, 432) associated with the wall of the bypass line (332, 432) and a cooling temperature associated with the coolant in the cooling circuit (320), and to selectively direct the control valve (310) based on the wall temperature of the bypass line (332, 432) and the coolant temperature wherein the control unit (500) is further configured to determine a dew point temperature associated with an environment and to selectively instruct the control valve (310) based additionally on the dew point temperature, wherein the control unit (500) is configured to instruct the control valve (310) to move to the closed position when the wall temperature of the bypass line (332, 432) is lower than the dew point temperature, and wherein the control unit (500) is configured to activate the heating device (334, 434) when the wall temperature of the bypass line (332, 432) is less than the dew point temperature. [2] Exhaust gas recirculation system according to claim 1, wherein the control unit (500) is configured to instruct the control valve (310) to move into the bypass position when the wall temperature of the bypass line (332, 432) exceeds the dew point temperature. [3] Exhaust gas recirculation system according to claim 2, wherein the control unit (500) is configured to deactivate the heating device (334, 434) when the wall temperature of the bypass line (332, 432) exceeds the dew point temperature. [4] Exhaust gas recirculation system according to claim 2, wherein the control unit (500) is configured to instruct the control valve (310) to move to the cooling position when the coolant temperature exceeds the dew point temperature. [5] Exhaust gas recirculation system according to claim 1, wherein the heating device (334, 434) comprises a resistance heating element wound spirally around the bypass line (332, 432). [6] Exhaust gas recirculation system according to claim 1, wherein the heating device (334, 434) comprises a resistance heating element arranged in a grid structure on the bypass line (332, 432).

Images