METHODS AND SYSTEMS FOR AN EXHAUST GAS RECIRCULATION COOLER

Abstract

Methods and systems are provided for an EGR cooler having first and second coolant jackets fluidly coupled to first and second coolant systems, respectively. In one example, the first and second coolant jackets are hermetically sealed from one another. Furthermore, the second coolant jacket protrudes into a portion of an exhaust gas passage directly downstream of an exhaust aftertreatment device.

Claims

1. A forced-induction internal combustion engine having at least one cylinder; an intake system for supplying the at least one cylinder with charge air; an exhaust system for discharging the exhaust gases, and an exhaust gas recirculation system, which has a recirculation line which, while forming a junction, branches off from the exhaust system and opens into the intake system, wherein a cooler is arranged in the recirculation line, which cooler has a core, which conducts coolant, is incorporated into a first coolant circuit and serves to transfer heat between the exhaust gas and the coolant, and where the cooler projects into the exhaust system in the region of the core, and at least one coolant jacket, which conducts coolant, is provided in the cooler, said jacket being arranged between the core conducting coolant and the exhaust system conducting exhaust gas and being incorporated into a second coolant circuit , wherein, to form the second coolant circuit, the at least one coolant jacket has a discharge line for discharging the coolant and a supply line for supplying the coolant.

2. The forced-induction internal combustion engine of claim 1, wherein the coolant of the second coolant circuit is stored in a container, which is at least connectable to the at least one coolant jacket of the second coolant circuit via the discharge line and via the supply line.

3. The forced-induction internal combustion engine of claim 2, further comprising a bypass line for bypassing the container is provided, said bypass line branching off from the discharge line and opening into the supply line, and where the bypass line further comprises a heat exchanger.

4. The forced-induction internal combustion engine of claim 3, wherein the bypass line comprises a third shutoff element upstream of the heat exchanger and a fourth shutoff element downstream of the heat exchanger.

5. The forced-induction internal combustion engine of claim 1, wherein in the discharge line comprises a first shutoff element, the supply line comprises a second shutoff element, and where the second coolant circuit comprises a pump arranged in the discharge line.

6. The forced-induction internal combustion engine of claim 1, wherein the junction is located directly downstream of an aftertreatment device.

7. The forced-induction internal combustion engine of claim 6, wherein the aftertreatment device is one or more of a particulate filter, oxidation catalyst, and a combination thereof

8. The forced-induction internal combustion engine of claim 1, wherein the exhaust gas recirculation system comprises a shutoff element, and where the shutoff element is located downstream of the cooler.

9. The forced-induction internal combustion engine of claim 1, further comprising a bypass line for bypassing the cooler.

10. The forced-induction internal combustion engine of claim 1, further comprising a controller with computer-readable instructions stored thereon that when executed enable the controller to: flow coolant from a coolant circuit not coupled to the engine to at least one coolant jacket of the cooler during a warm-up phase of the engine.

11. A method, comprising: flowing coolant from a first coolant circuit to a first coolant jacket of an exhaust gas recirculation cooler; flowing coolant from a second coolant circuit to a second coolant jacket of the exhaust gas recirculation cooler; and heating coolant in the first coolant jacket with coolant in the second coolant jacket when exhaust gas recirculation is deactivated.

12. The method of claim 11, wherein the first coolant circuit is fluidly coupled to an engine when a first coolant outflow valve is open and an engine inlet line valve is open.

13. The method of claim 11, wherein flowing coolant from the second coolant circuit to the second coolant jacket occurs following a cold-start.

14. The method of claim 11, wherein flowing coolant from the second coolant circuit to the second coolant jacket occurs when a coolant temperature in the first coolant jacket is greater than or equal to an upper threshold temperature.

15. The method of claim 11, wherein flowing coolant from the second coolant circuit to the second coolant jacket occurs when an amount of condensate in an EGR cooler is greater than or equal to a threshold condensate amount.

16. A system comprising: an EGR cooler arranged in an EGR passage, where the cooler comprises a first coolant jacket hermetically sealed from a second coolant jacket, and where a portion of the cooler comprising the second coolant jacket protrudes into a portion of an exhaust passage directly downstream of an aftertreatment device.

17. The system of claim 16, wherein the first coolant jacket is fluidly coupled to a first coolant circuit, the first coolant circuit being fluidly coupled to an engine, and where the second coolant jacket is fluidly coupled to a second coolant circuit.

18. The system of claim 16, wherein the second coolant jacket is located between the exhaust passage and the first coolant jacket.

19. The system of claim 16, wherein the second coolant jacket is in direct thermal communication with exhaust gas in the exhaust passage and where the first coolant jacket is in direct thermal communication with exhaust gas in the EGR cooler.

20. The system of claim 16, further comprising a controller with computer-readable instructions that when executed enable the controller to: flow coolant from the second coolant circuit to the second coolant jacket when EGR is not desired, and flow air from the second coolant circuit to the second coolant jacket when exhaust heat energy is not desired.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0097] FIG. 1 shows schematically a fragment of the exhaust system of a first embodiment of the forced-induction internal combustion engine together with the exhaust gas recirculation system and coolant circuits.

[0098] FIG. 2 shows a schematic for an engine having at least one cylinder.

[0099] FIG. 3 shows an illustration of a first coolant circuit fluidly coupled to the first coolant jacket and a second coolant circuit fluidly coupled to the second coolant jacket.

[0100] FIG. 4 shows a high-level flow chart for flowing coolant.

[0101] FIG. 5 shows a detailed flow chart for utilizing exhaust heat energy when EGR is not desired.

[0102] FIG. 6 shows a method for cooling coolant in a first coolant jacket by flowing coolant to a second coolant jacket.

[0103] FIG. 7 shows a method for limiting condensate formation in the EGR cooler.

[0104] FIG. 8 shows an engine operating sequence illustrating one or more of the above methods using in conjunction with the EGR cooler and coolant jackets located therein.

DETAILED DESCRIPTION

[0105] The following description relates to systems and methods for an EGR cooler having a first coolant jacket fluidly separated from a second coolant jacket. The second coolant jacket is smaller than the first coolant jacket, and is located at an interface between the EGR cooler and the particulate filter outlet. This is shown in FIG. 1. The first coolant jacket is configured to cool exhaust gas and is fluidly coupled to a first coolant system configured to adjust engine combustion and engine oil temperatures, as is known in the art. The second coolant jacket may be used under a plurality of conditions, including but not limited to mitigating condensate formation, increasing engine oil and/or engine combustion temperatures, and decreasing a first coolant jacket temperature, as shown in FIGS. 4-7. An engine having at least one combustion chamber with an exhaust passage coupled thereto having the EGR cooler described above is shown in FIG. 2. First and second coolant circuits fluidly coupled to the first and second coolant jackets, respectively, are shown in FIG. 3. FIG. 8 graphically displays engine operating parameters overtime as one or more of the methods described herein as used in conjunction with the coolant jackets of the EGR cooler.

[0106] The internal combustion engine has an exhaust system 1 for discharging the exhaust gases from the cylinders.

[0107] The forced-induction internal combustion engine is fitted with an exhaust gas recirculation system 2. To form the exhaust gas recirculation system 2, a recirculation line 2a is provided, which, while forming a junction 1a, branches off from the exhaust system 1 and opens into the intake system and in which a cooler 3 is arranged, which, when the exhaust gas recirculation system 2 is activated, lowers the temperature in the hot exhaust gas to be recirculated before the recirculated exhaust gas is mixed with fresh air in the intake system.

[0108] Arranged in the recirculation line 2a there is furthermore a shutoff element 4, which acts as an EGR valve 4 and is used to set the recirculated exhaust gas volume. The exhaust gas recirculation system 2 optionally has a bypass line for bridging the cooler 3 (not shown).

[0109] The cooler 3 has an outlet cone 3d and a core 3a, which conducts coolant 3c, wherein the core 3a is incorporated into a first coolant circuit 3b and the coolant flow 3c circulating or passed through the core 3a removes heat from the hot exhaust gas. The heat transferred to the coolant 3c from the exhaust gas is fed to a predeterminable use, i.e. the exhaust gas energy is made usable or is used. The efficiency of the internal combustion engine is thereby increased.

[0110] The cooler 3 projects into the exhaust system 1 in the region of the core 3a, with the result that there is a flow of hot exhaust gas around at least some area or areas of the core 3a conducting coolant 3c, or that this/these are subjected to hot exhaust gas, even when the exhaust gas recirculation system 2 is deactivated and no exhaust gas at all is being recirculated. By virtue of this arrangement of the EGR cooler 3 in the exhaust system 1, the hot exhaust gas can be used even when the exhaust gas recirculation system 2 is deactivated.

[0111] The arrangement of the cooler 3 furthermore makes it possible to eliminate an inlet cone in order to increase the cross section of the recirculation line 2a to the larger cross section of the core 3a. Eliminating the inlet cone allows a compact design of the exhaust gas recirculation system 2 overall and dense packaging in the engine compartment.

[0112] A coolant jacket 6a of a second coolant circuit 6b is furthermore provided in the cooler 3, said coolant jacket conducting coolant 6c and being arranged between the core 3a conducting coolant 3c and the exhaust system 1 conducting exhaust gas. To form the second coolant circuit 6b, a discharge line 6d for discharging the coolant 6c and a supply line 6e for supplying the coolant 6c are provided, as is a container 8 for storing the coolant 6c, wherein the container 8 can be connected to the coolant jacket 6a via discharge line 6d and supply line 6e.

[0113] The coolant jacket 6a is intended to thermally couple or separate the core 3a conducting coolant 3c and the exhaust system 1 conducting exhaust gas. For this purpose, the coolant jacket 6a of the second coolant circuit 6b can either be filled with coolant 6c or freed from coolant 6c and emptied.

[0114] A coolant jacket 6a filled with coolant 6c serves as a thermal bridge for the introduction of heat from the exhaust gas into the coolant 3c in the core 3a. In this case, the coolant 6c in the coolant jacket 6a preferably does not circulate in the second coolant circuit 6b.

[0115] A coolant jacket 6a freed from coolant 6c, i.e. at least partially emptied, serves as a thermal barrier, which is intended to make the introduction of heat from the exhaust gas into the coolant 3c in the core 3a more difficult or to prevent it.

[0116] A first shutoff element 7a is arranged in the discharge line 6d, and a second shutoff element 7b is arranged in the supply line 6e. Opening the first shutoff element 7a allows coolant 6c to be discharged into the container 8, i.e. allows emptying of the coolant jacket 6a. Closing the first shutoff element 7a prevents coolant from draining into the container 8 and circulation of coolant 6c in the second coolant circuit 6b via the container 8. The opened second shutoff element 7b allows the coolant jacket 6a to be filled with coolant 6c from the container 8.

[0117] To deliver the coolant 6c in the second coolant circuit 6b, a pump 9 is provided in the discharge line 6d, which pump can be used to empty or fill the coolant jacket 6a and to circulate the coolant 6c in the second coolant circuit 6b.

[0118] In the present case, a bypass line 10 for bypassing the container 8 is provided, said bypass line branching off from the discharge line 6d between the pump 9 and the first shutoff element 7a and opening into the supply line 6e downstream of the second shutoff element 7b.

[0119] Arranged in the bypass line 10 is a radiator 11a, which acts as a heat exchanger 11 and removes heat from the coolant 6c in the second coolant circuit 6b by virtue of convection owing to a supply of air.

[0120] If the coolant 6c in the filled coolant jacket 6a overheats and there is a risk of evaporation of coolant 6c, the coolant 6c in the second coolant circuit 6b can circulate via bypass line 10 in order to dissipate in the radiator 11a the heat introduced into the coolant 6c from the exhaust gas. Arranged in the bypass line 10 there is a third shutoff element 7c upstream of the heat exchanger 11 and a fourth shutoff element 7d downstream of the heat exchanger 11. Opening the third and fourth shutoff elements 7c, 7d serve to release the bypass line 10 if the coolant 6c in the second coolant circuit 6b is supposed to circulate and flow through the coolant jacket 6a. The first and second shutoff elements 7a, 7b are closed during this process.

[0121] A particle filter 5a is provided as an exhaust gas aftertreatment system 5 upstream of the junction 1a in order to aftertreat the exhaust gas.

[0122] In this way, FIG. 1 shows an EGR cooler having first and second coolant jackets fluidly coupled to separate coolant circuits. The second coolant jacket is in thermal communication with exhaust gas in an exhaust passage directly downstream of a particulate filter. The first jacket is not in thermal communication with exhaust gas in the exhaust passage, but is in thermal communication with exhaust gas flowing through the EGR cooler. As such, coolant in the second coolant jacket is heated by exhaust gas in the exhaust gas passage and coolant in the first coolant jacket is heated by exhaust gas in the EGR cooler. Additionally, the coolants in the separate coolant jackets may thermally communicate with one another. As such, exhaust heat energy may be utilized even when EGR is off.

[0123] Turning now to FIG. 2, a schematic diagram showing one cylinder of a multi-cylinder engine 20 in an engine system 100, which may be included in a propulsion system of an automobile, is shown. The engine 20 may be controlled at least partially by a control system including a controller 12 and by input from a vehicle operator 132 via an input device 130. In this example, the input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal. A combustion chamber 30 of the engine 20 may include a cylinder formed by cylinder walls 32 with a piston 36 positioned therein. The piston 36 may be coupled to a crankshaft 40 so that reciprocating motion of the piston is translated into rotational motion of the crankshaft. The crankshaft 40 may be coupled to at least one drive wheel of a vehicle via an intermediate transmission system. Further, a starter motor may be coupled to the crankshaft 40 via a flywheel to enable a starting operation of the engine 20.

[0124] The combustion chamber 30 may receive intake air from an intake manifold 44 via an intake passage 42 and may exhaust combustion gases via an exhaust passage 48. The intake manifold 44 and the exhaust passage 48 can selectively communicate with the combustion chamber 30 via respective intake valve 52 and exhaust valve 54. In some examples, the combustion chamber 30 may include two or more intake valves and/or two or more exhaust valves.

[0125] In this example, the intake valve 52 and exhaust valve 54 may be controlled by cam actuation via respective cam actuation systems 51 and 53. The cam actuation systems 51 and 53 may each include one or more cams and may utilize one or more of cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and/or variable valve lift (VVL) systems that may be operated by the controller 12 to vary valve operation. The position of the intake valve 52 and exhaust valve 54 may be determined by position sensors 55 and 57, respectively. In alternative examples, the intake valve 52 and/or exhaust valve 54 may be controlled by electric valve actuation. For example, the cylinder 30 may alternatively include an intake valve controlled via electric valve actuation and an exhaust valve controlled via cam actuation including CPS and/or VCT systems.

[0126] A fuel injector 69 is shown coupled directly to combustion chamber 30 for injecting fuel directly therein in proportion to the pulse width of a signal received from the controller 12. In this manner, the fuel injector 69 provides what is known as direct injection of fuel into the combustion chamber 30. The fuel injector may be mounted in the side of the combustion chamber or in the top of the combustion chamber, for example. Fuel may be delivered to the fuel injector 69 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. In some examples, the combustion chamber 30 may alternatively or additionally include a fuel injector arranged in the intake manifold 44 in a configuration that provides what is known as port injection of fuel into the intake port upstream of the combustion chamber 30.

[0127] Spark is provided to combustion chamber 30 via spark plug 66. The ignition system may further comprise an ignition coil (not shown) for increasing voltage supplied to spark plug 66. In other examples, such as a diesel, spark plug 66 may be omitted.

[0128] The intake passage 42 may include a throttle 62 having a throttle plate 64. In this particular example, the position of throttle plate 64 may be varied by the controller 12 via a signal provided to an electric motor or actuator included with the throttle 62, a configuration that is commonly referred to as electronic throttle control (ETC). In this manner, the throttle 62 may be operated to vary the intake air provided to the combustion chamber 30 among other engine cylinders. The position of the throttle plate 64 may be provided to the controller 12 by a throttle position signal. The intake passage 42 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 for sensing an amount of air entering engine 20.

[0129] An exhaust gas sensor 126 is shown coupled to the exhaust passage 48 upstream of an emission control device 72 according to a direction of exhaust flow. The sensor 126 may be any suitable sensor for providing an indication of exhaust gas air-fuel ratio such as a linear oxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), a two-state oxygen sensor or EGO, a HEGO (heated EGO), a NO.sub.x, HC, or CO sensor. In one example, upstream exhaust gas sensor 126 is a UEGO configured to provide output, such as a voltage signal, that is proportional to the amount of oxygen present in the exhaust. Controller 12 converts oxygen sensor output into exhaust gas air-fuel ratio via an oxygen sensor transfer function.

[0130] The emission control device 72 is shown arranged along the exhaust passage 48 downstream of both the exhaust gas sensor 126. The device 72 may be a three way catalyst (TWC), NO.sub.x trap, selective catalytic reductant (SCR), various other emission control devices, or combinations thereof. In some examples, during operation of the engine 20, the emission control device 72 may be periodically reset by operating at least one cylinder of the engine within a particular air-fuel ratio.

[0131] An exhaust gas recirculation (EGR) system 140 may route a desired portion of exhaust gas from the exhaust passage 48 to the intake manifold 44 via an EGR passage 152. The amount of EGR provided to the intake manifold 44 may be varied by the controller 12 via an EGR valve 144. Under some conditions, the EGR system 140 may be used to regulate the temperature of the air-fuel mixture within the combustion chamber, thus providing a method of controlling the timing of ignition during some combustion modes. The EGR system further includes an EGR cooler 142 located at a junction between the exhaust gas passage 48 and the EGR passage 152. A portion of the EGR cooler extends into the exhaust passage 48 at an area directly downstream of an emission control device 71. In one example, the emission control device 71 is substantially identical to the emission control device 72. Additionally or alternatively, the emission control device 71 is a particulate filter and the emission control device is a different aftertreatment device (e.g., a three-way catalyst). In one example, the EGR cooler 142 is substantially similar to the EGR cooler 3 of FIG. 1. In this way, the EGR cooler 142 comprises two coolant jackets, with one of the coolant jackets being thermally coupled to exhaust gas in the exhaust gas passage.

[0132] The controller 12 is shown in FIG. 2 as a microcomputer, including a microprocessor unit 102, input/output ports 104, an electronic storage medium for executable programs and calibration values shown as read only memory chip 106 (e.g., non-transitory memory) in this particular example, random access memory 108, keep alive memory 110, and a data bus. The controller 12 may receive various signals from sensors coupled to the engine 20, in addition to those signals previously discussed, including measurement of inducted mass air flow (MAF) from the mass air flow sensor 120; engine coolant temperature (ECT) from a temperature sensor 112 coupled to a cooling sleeve 114; an engine position signal from a Hall effect sensor 118 (or other type) sensing a position of crankshaft 40; throttle position from a throttle position sensor 65; and manifold absolute pressure (MAP) signal from the sensor 122. An engine speed signal may be generated by the controller 12 from crankshaft position sensor 118. Manifold pressure signal also provides an indication of vacuum, or pressure, in the intake manifold 44. Note that various combinations of the above sensors may be used, such as a MAF sensor without a MAP sensor, or vice versa. During engine operation, engine torque may be inferred from the output of MAP sensor 122 and engine speed. Further, this sensor, along with the detected engine speed, may be a basis for estimating charge (including air) inducted into the cylinder. In one example, the crankshaft position sensor 118, which is also used as an engine speed sensor, may produce a predetermined number of equally spaced pulses every revolution of the crankshaft.

[0133] The storage medium read-only memory 106 can be programmed with computer readable data representing non-transitory instructions executable by the processor 102 for performing the methods described below as well as other variants that are anticipated but not specifically listed.

[0134] The controller 12 receives signals from the various sensors of FIG. 2 and employs the various actuators of FIG. 2 to adjust engine operation based on the received signals and instructions stored on a memory of the controller. For example, adjusting a reactivity of the SCR may include adjusting an actuator of the urea injector to inject urea to cover surfaces of the SCR with urea. For example, adjusting an injection into the mixer may include adjusting an actuator of the injector to open an orifice of the injector to spray an amount of fluid into the mixer.

[0135] Turning now to FIG. 3, it shows an embodiment 300 of a first coolant circuit 302 fluidly coupled to a first coolant jacket 304 and a second coolant circuit 306 fluidly coupled to a second coolant jacket 308. The first coolant jacket 304 may be substantially identical to the core of the cooler 3a of FIG. 1. As such, the first coolant circuit 302, along with one or more components located therein, may be used similarly to the first coolant circuit 3b of FIG. 1. Likewise, the second coolant jacket 307 may be substantially identical to the coolant jacket 6a of FIG. 1. As such, the second coolant circuit 306, along with one or more components located therein (e.g., pump 342 may be substantially similar to pump 8), may be used similarly to the second coolant circuit 6b.

[0136] The first coolant circuit 302 comprises a degas bottle 303, a radiator 301, and the engine 20 of FIG. 1. In this way, the first coolant circuit 302 may be a primary coolant circuit, wherein coolant from the first coolant circuit 302 flows through and thermally communicates with one or more engine components. For example, the first coolant circuit 302 is configured to adjust one or more of an engine combustion temperature, engine oil temperature, transmission oil temperature, etc. Additionally, the first coolant circuit 302 is configured to adjust a temperature of exhaust gas flowing through the EGR cooler 142. Specifically, the first coolant circuit 302 delivers coolant to the first coolant jacket 304, which is in face-sharing contact with exhaust gas flowing through the EGR cooler 142. However, the first coolant jacket 304 is not in face-sharing contact and does not thermally communicate with exhaust gas outside of the EGR cooler 142 (e.g., exhaust gas in the exhaust passage).

[0137] A first coolant outflow line 310 comprises a pump 312 configured to assist in coolant flow to and from the first coolant jacket 304. The first outflow line 310 is fluidly coupled to the radiator 301 and a degas inlet line 320. If a first outflow line valve 314 is in a more open position, then at least some coolant from the first coolant outflow line 310 flows to the radiator 301. Likewise, if a degas inlet line valve 324 is in a more open position, then at least some coolant from the first coolant outflow line 310 flows to the degas bottle 303. In one example, a more open position of a valve allows a greater amount of coolant or other substance to flow therethrough compared to a less open position (e.g., a more closed position). As such, coolant flow from the first coolant jacket 304 to the radiator 301 and the degas bottle 303 may be at least partially adjusted by the pump 312, the first outflow line valve 314, and the degas inlet line valve 324.

[0138] If the first outflow line valve 314 is in a fully closed position and the degas inlet line valve 324 is in a fully open position, then all the coolant from the first coolant jacket 304 is directed to the degas bottle 303, where air and/or other gases are removed from the first coolant circuit 302. Coolant from the degas bottle 303 may be directed back to the first coolant jacket 304 when a degas outflow line valve 326 of a degas outflow line 322 is in an at least partially open position. The coolant flows through the degas outflow line 322, through the partially open degas outflow line valve 326, and into the first coolant inlet line 316. The first coolant inlet line 316 directs the depressurized coolant from the degas bottle 303 to the first coolant jacket 304.

[0139] If the first outline line valve 314 is in the fully open position and the degas inlet line valve 324 is in the fully closed position, then coolant from the first coolant jacket flows to the radiator 301 and does not flow to the degas bottle 303. Coolant in the first radiator 301 may be cooled via ram air and/or air flow from a mechanical device (e.g., a fan). The first radiator 301 is further configured to direct coolant to the engine 20 via an engine inlet line 330 and engine inlet line valve 332. If the engine inlet line valve 332 is in an at least partially open position, then coolant from the radiator 301 may flow to the engine 20. In one example, coolant flowing to the engine 20 flows into a combustion chamber cooling sleeve 114. In this way, the coolant from the first coolant circuit may thermally communicate with one or more engine components (e.g., combustion chamber coolant jacket, engine oil, etc.). Coolant may flow to the radiator 301 from the engine 20 via an engine outflow line 334 and engine outflow line valve 336. In one example, if the engine outflow line valve 336 is in an at least partially open position then coolant from the engine 20 flows to the radiator 301.

[0140] Coolant may flow from the radiator 301 and to the first coolant jacket 304 via the first coolant inlet line 316 when a first coolant inlet line valve 318 is in an at least partially open position. Coolant flowing through the at least partially open first coolant inlet line valve 318 flows to only the first coolant jacket 304 and does not flow into the degas bottle 303. In one example, additionally or alternatively, the radiator 301 may comprise a separate coolant line directly coupling it to the degas bottle 303.

[0141] The second coolant circuit 306 is fluidly coupled to the second coolant jacket 307, a degas bottle 308, and a radiator 309. As shown, the degas bottle 308 and the radiator 309 are fluidly separated from the radiator 301 and the degas bottle 303. The second coolant jacket 307 is configured to thermally communicate with exhaust gas flowing through the EGR cooler 142 and/or through an exhaust passage. In this way, the second coolant jacket 307 may thermally communicate with exhaust gas even when the exhaust gas is not flowing through the EGR cooler 142. Additionally, the second coolant jacket 307 is configured to become thermally insulated from exhaust gas flowing through the exhaust passage. This may be accomplished by vacating the second coolant jacket 307 of coolant and filling it with air. Coolant may flow out of the second coolant jacket 307 via a second coolant outflow line 340. A pump 342 is arranged in the second jacket outflow line 340, where the pump 342 may assist coolant flow through the second coolant circuit 306. The second coolant outflow line 340 is fluidly coupled to a radiator inlet line 350 and the degas bottle 308. If a radiator inlet line valve 352 is in a fully closed position and a degas bottle inlet valve 344 is in a fully open position, then coolant from the second coolant jacket 307 flows to the degas bottle 308 without flowing to the radiator 309. Coolant in the degas bottle may be depressurized and flow back to the second coolant jacket 307 when a degas bottle outlet valve 346, arranged along a second coolant inlet line 348, is in an at least partially open position.

[0142] If the radiator inlet line valve 352 is in the fully open position and the degas bottle inlet line valve 344 is in the fully closed position, then coolant from the second coolant jacket 307 flows to only the radiator 309 via the radiator inlet line 350 without flowing to the degas bottle 308. The radiator 309 may adjust a temperature of coolant in the second coolant circuit 306 via ram air and/or one or more devices (e.g., a fan). Coolant may flow from the radiator to the second coolant jacket 307 when a radiator outlet line valve 354, which is arranged in a radiator outlet line 356, is in an at least partially open position. Coolant flows from the radiator 309, through the at least partially open radiator outlet line valve 354, through the radiator outlet line 356, into the second coolant inlet line 348, and into the second coolant jacket 307. In some example, the radiator 309 may comprise separate passages directly coupling the radiator 309 to the degas bottle 308.

[0143] As shown, the first coolant circuit 302 is hermetically sealed from the second coolant circuit 306. In this way, coolant in the first coolant circuit 302 does not mix and/or merge and/or combine with coolant in the second coolant circuit 306. In one example, coolant in the first coolant circuit 302 only thermally communicates with coolant in the second coolant circuit at an interface between the first coolant jacket 304 and the second coolant jacket 307. As shown, the second coolant jacket 307 surrounds at least a portion of the fist coolant jacket 304. As described above, the second coolant jacket 307 extends into a portion of an exhaust passage directly downstream of a particulate filter. In one example, the second coolant jacket 307 is the only portion of the EGR cooler 142 in thermal communication with exhaust gas in the exhaust passage. As such, the remaining portion of the EGR cooler 142 may thermally communicate directly with exhaust gas when exhaust gas is flowing directly through the EGR cooler 142. However, by protruding the second coolant jacket 307 into the exhaust gas passage, thermally energy of exhaust gas may be supplied from the second coolant jacket 307 to the first coolant jacket 304, without flowing exhaust gas through the EGR cooler 142. This will be described in greater detail below. Methods for adjusting coolant flow to the second coolant jacket for heating coolant in the first coolant jacket, cooling coolant in the first coolant jacket via coolant in the second coolant jacket 307, and thermally insulating coolant in the first coolant jacket 304 from exhaust gas in the exhaust gas passage are described below.

[0144] While components of the first 302 and second 306 coolant circuits are shown separate and different than one another, it will be appreciated that in some embodiments, the coolant circuits may share one or more of a radiator and a degas bottle.

[0145] Thus, a system comprises an EGR cooler arranged in an EGR passage, where the cooler comprises a first coolant jacket hermetically sealed from a second coolant jacket, and where a portion of the cooler comprising the second coolant jacket protrudes into a portion of an exhaust passage directly downstream of an aftertreatment device. The first coolant jacket is fluidly coupled to a first coolant circuit, the first coolant circuit being fluidly coupled to an engine, and where the second coolant jacket is fluidly coupled to a second coolant circuit. The second coolant jacket is located between the exhaust passage and the first coolant jacket. The second coolant jacket is in direct thermal communication with exhaust gas in the exhaust passage and where the first coolant jacket is in direct thermal communication with exhaust gas in the EGR cooler. A controller with computer-readable instructions that when executed enable the controller to flow coolant from the second coolant circuit to the second coolant jacket when EGR is not desired, and flow air from the second coolant circuit to the second coolant jacket when exhaust heat energy is not desired.

[0146] Turning now to FIG. 4, it shows a high-level flow chart illustrating a method 400 for flowing coolant to the second coolant jacket. Instructions for carrying out method 400 and the rest of the methods included herein may be executed by a controller (e.g., controller 12) based on instructions stored on a memory of the controller and in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to FIG. 2. The controller may employ engine actuators of the engine system to adjust engine operation, according to the methods described below.

[0147] The method 400 may begin at 402, where the method determines, estimates, and/or measures current engine operating parameters. Current engine operating parameters may include, but is not limited to, one or more of an engine speed, engine temperature, vehicle speed, manifold pressure, and air/fuel ratio.

[0148] At 404, the method determines if exhaust heat energy is desired. Exhaust heat energy may be desired if an engine temperature is less than a threshold engine temperature and if an engine oil temperature is less than a threshold oil temperature. Additionally or alternatively, exhaust heat energy may be desired if a likelihood of condensate forming in the EGR cooler is greater than a threshold likelihood. At any rate, if exhaust heat energy is not desired, then the method proceeds to 406 to flow oxygen to the second coolant jacket. In this way, the second coolant jacket is vacated of coolant. The oxygen fills the second coolant jacket, which thermally insulates coolant in the first coolant jacket from exhaust gas flowing through an exhaust passage. In this way, air in the second coolant jacket is marginally heated (e.g., less than 1° C.) by exhaust gas in the exhaust gas passage such that a temperature of coolant in the first coolant jacket is unchanged.

[0149] If the exhaust heat energy is desired, then the method proceeds to 408 to determine if EGR is desired. If EGR is desired, then the method proceeds to 410 to flow EGR through the EGR cooler. In some example, flowing EGR through the EGR cooler includes flowing coolant to the first coolant jacket and not flowing coolant to the second coolant jacket. As such, the second coolant jacket may be filled with air during certain instances of EGR flow. Additionally or alternatively, coolant from the first coolant circuit may flow to the first coolant jacket and coolant from the second coolant circuit may flow to the second coolant jacket when EGR is desired. As such, both coolant jackets may thermally communicate with each other and exhaust gas.

[0150] If EGR is not desired, then the method proceeds to 412 to flow coolant from the second coolant circuit to the second coolant jacket. In this way, exhaust gas in the exhaust passage may heat coolant in the second coolant jacket. Coolant in the second coolant jacket may thermally communicate with coolant in the first coolant jacket, thereby realizing the benefits of exhaust heat energy without flowing EGR. This may be desired following a cold-start where engine oil and/or other engine components are below desired temperatures.

[0151] At 414, the method includes not flowing EGR through the EGR cooler.

[0152] Thus, a method, comprising flowing coolant from a first coolant circuit to a first coolant jacket of an exhaust gas recirculation cooler, flowing coolant from a second coolant circuit to a second coolant jacket of the exhaust gas recirculation cooler, and heating coolant in the first coolant jacket with coolant in the second coolant jacket when exhaust gas recirculation is deactivated. The first coolant circuit is fluidly coupled to an engine. The flowing coolant from the second coolant circuit to the second coolant jacket occurs following a cold-start. The flowing coolant from the second coolant circuit to the second coolant jacket occurs when a coolant temperature in the first coolant jacket is greater than or equal to an upper threshold temperature. The flowing coolant from the second coolant circuit to the second coolant jacket occurs when an amount of condensate in an EGR cooler is greater than or equal to a threshold condensate amount.

[0153] Turning now to FIG. 5, a method 500 for utilizing exhaust heat energy following a cold-start when EGR is undesired is shown. The method includes flowing coolant from the second circuit to the second coolant jacket following completion of a cold-start. Since EGR is undesired, the coolant in the second coolant jacket is heated by the hot exhaust gas. The hot coolant in the second coolant jacket heats the coolant in the first coolant jacket, which may flow through the first coolant circuit, as shown in FIG. 3.

[0154] The method 500 begins at 502, where the method determines, estimates, and/or measures current engine operating parameters. Current engine operating parameters may include, but is not limited to, one or more of an engine speed, engine temperature, vehicle speed, manifold pressure, and air/fuel ratio.

[0155] At 504, the method includes determining if a cold-start was recently completed. The cold-start is recent if it is within a threshold amount of time (e.g., 30 seconds). A cold-start is completed if an engine temperature is greater than an ambient temperature, in one example. If a cold-start was not recently completed or if a cold-start is still ongoing, then the method proceeds to 506 to maintain current engine operating parameters. Additionally or alternatively, the method includes flowing air to the second coolant jacket and vacating the second coolant jacket of coolant. In other embodiments, additionally or alternatively, coolant from the second coolant circuit flows to the second coolant jacket.

[0156] If the cold-start was recently completed, then the method proceeds to 508 to flow coolant from the second coolant circuit to the second coolant jacket. It will be appreciated that coolant from the first coolant circuit may already occupy the first coolant jacket. In this way, the coolant in the second coolant jacket is heated by hot exhaust gas flowing through the exhaust passage. The hot exhaust gas does not flow through the EGR cooler since EGR is undesired following the cold-start. In this way, a temperature of the coolant in the second coolant jacket rises, which may increase a temperature of coolant in the first coolant jacket.

[0157] At 510, the method includes flowing the coolant from the first jacket to the engine, where the coolant may reduce engine friction by heating engine oil and/or increase an engine operating temperature. In this way, exhaust heat energy is utilized outside of an EGR demand. By doing this, exhaust heat energy may more rapidly heat engine components compared to a vehicle lacking a second coolant jacket, such as the second coolant jacket described above.

[0158] At 512, the method includes determining if exhaust heat energy is still desired. This may include determining if the engine components are sufficiently hot. This may include comparing an engine oil temperature to a threshold oil temperature, where the threshold oil temperature is based on sufficient lubrication and reduction in friction of engine components. If the engine components are not sufficiently hot and exhaust heat energy is still desired, then the method proceeds to 514 to continue flowing coolant to the second coolant jacket. This allows the coolant in the second coolant jacket to continue heating coolant in the first coolant jacket without flowing exhaust gas through EGR cooler.

[0159] If the engine components are sufficiently heated and exhaust heat energy is no longer desired, then the method proceeds to 516 to flow coolant out of the second coolant jacket. This may include activating a pump (e.g., pump 342 of FIG. 3) opening one or more valves (e.g., at least partially opening one or more of the degas inlet line valve 344 and the radiator inlet line valve 352. At 518, the method includes filling the second coolant jacket with air. This may include maintaining the degas outlet valve 346 and the radiator outlet line valve 354 closed such that air may fill the second coolant jacket as coolant flows out. As described above, filling the second coolant jacket with air may thermally insulate coolant in the first coolant jacket from exhaust gas in the exhaust passage.

[0160] Turning now to FIG. 6, it shows a method 600 adjusting a temperature of coolant in the first coolant jacket by flowing coolant to the second coolant jacket when EGR is enabled. As such, the coolant from the second coolant circuit may cool coolant from the first coolant circuit when EGR is flowing through the EGR cooler. As such, the method 600 is implemented when EGR is flowing and the second coolant jacket is filled with air.

[0161] The method 600 begins at 602, where the method determines, estimates, and/or measures current engine operating parameters. Current engine operating parameters may include, but is not limited to, one or more of an engine speed, engine temperature, vehicle speed, manifold pressure, EGR flow rate, and air/fuel ratio.

[0162] At 604, the method includes determining if a first coolant jacket temperature is greater than or equal to an upper threshold temperature. In one example, the upper threshold temperature is based on a coolant temperature where the coolant may begin to overheat (e.g., boil). If the first coolant jacket temperature is less than the upper threshold temperature, then the method proceeds to 606 to maintain current engine operating parameters and does not flow coolant from the second coolant circuit to the second coolant jacket. In this way, only the first coolant jacket of the EGR cooler is filled with coolant.

[0163] If the first coolant jacket temperature is greater than or equal to the upper threshold temperature, the coolant in the first coolant jacket is too hot. As such, the method proceeds to 608 to flow coolant from the second coolant circuit to the second coolant jacket. Since the coolant in the second coolant circuit has not been exposed to exhaust gas, its temperature is less than a temperature of coolant in the first coolant jacket. In this way, cool coolant from the second coolant circuit fills the second coolant jacket, where the second coolant jacket thermally communicates with coolant in the first coolant jacket and decreases a temperature of the first coolant jacket.

[0164] At 610, the method includes determining if the first coolant jacket temperature is less than the upper threshold temperature. If the first coolant jacket temperature is still greater than or equal to the upper threshold temperature, then the method proceeds to 612 to continue flowing coolant from the second coolant circuit to the second coolant jacket.

[0165] If the first coolant jacket temperature is less than the upper threshold temperature, then the method includes flowing air to the second coolant jacket and removing coolant from the second coolant jacket at 614. In this way, the coolant from the second coolant jacket is directed to one or more of a degas bottle and a radiator located along the second coolant circuit. Additionally, coolant in the second coolant circuit is thermally isolated from exhaust gas. By doing this, only coolant from the first coolant circuit may continue thermally communicating with exhaust gas.

[0166] Turning now to FIG. 7, it shows a method 700 for mitigating condensate formation in the EGR cooler. As an example, the second coolant circuit may flow coolant to the second coolant jacket prior to flowing EGR through the EGR cooler. This may heat surfaces of the EGR cooler, which may decrease a likelihood for condensate formation in the EGR cooler.

[0167] The method 700 begins at 702, where the method determines, estimates, and/or measures current engine operating parameters. Current engine operating parameters may include, but is not limited to, one or more of an engine speed, engine temperature, vehicle speed, manifold pressure, exhaust gas temperature, EGR flow rate, and air/fuel ratio.

[0168] At 704, the method includes determining if EGR is desired. In one example, EGR is desired if an engine temperature is approaching an upper threshold engine temperature, which may correspond with an engine temperature where degradation may occur and/or NO.sub.x emissions are greater than desired. If EGR is not desired, then the method proceeds to 706 to maintain current engine operating parameters and does not flow coolant from the second coolant circuit to the second coolant jacket of the EGR cooler.

[0169] If EGR is desired, then the method proceeds to 708 to estimate EGR condensate already present in the ERG cooler. This may include gathering data from a look-up table corresponding to EGR cooler temperatures, EGR flow rates, and EGR temperatures for previous engine conditions using EGR. In one example, an amount of condensate in the EGR cooler is tracked over time by estimating an amount of condensate likely to form in the EGR cooler subtracted by an amount of condensate swept out of the cooler by EGR. In one example, the amount of condensate likely to form in the EGR cooler increases when one or more of a water content of exhaust gas increases, when an exhaust gas temperature increases, and when an EGR cooler temperature decreases. Condensate in the EGR cooler may decrease as EGR continues to flow through the EGR cooler. The condensate is carried to the engine, which may decrease combustion stability if too much condensate is swept to the engine.

[0170] At 710, the method includes determining if the EGR cooler condensate is greater than or equal to a threshold condensate, wherein the threshold condensate correspond to an amount of condensate which may result in decreased combustion stability. If the EGR cooler condensate is less than the threshold condensate, then the method proceeds to 712 to flow EGR and does not flow coolant from the second coolant circuit to the second coolant jacket. In this way, an amount of condensate estimated to form in the EGR cooler, along with the amount of condensate already present in the EGR cooler, will not exceed the threshold condensate amount, and pre-heating of the EGR cooler is not needed.

[0171] If the cooler condensate is greater than or equal to the threshold condensate and condensate formed on during a subsequent EGR flow will inhibit engine efficiency, then the method proceeds to 714 to flow coolant from the second coolant circuit to the second coolant jacket for a threshold duration of time. In this way, the coolant in the second coolant jacket may be heated by exhaust gas in the exhaust gas passage prior to flowing EGR through the EGR cooler. This may allow the coolant in the first coolant jacket to warm-up, thereby increasing an EGR core temperature, which may mitigate condensate formation in the EGR cooler.

[0172] At 716, the method includes determining if the threshold duration is complete. The EGR cooler is pre-heated for a threshold duration of time. In one example, the threshold duration is a fixed duration (e.g., 20 seconds). In other examples, the threshold duration may be based on a difference between the amount of condensate present in the cooler and the threshold condensate, when the difference increases, the threshold duration increases. If the threshold duration is not complete, then the method proceeds to 718 to continue flowing coolant from the second coolant circuit to the second coolant jacket.

[0173] If the threshold duration is complete and the EGR cooler is sufficiently heated, then the method proceeds to 720 flow EGR through the EGR cooler. In some examples, the method may further include flowing air to the second coolant jacket, which results in coolant from the second coolant jacket flowing to one or more of a degas bottle and radiator of the second coolant circuit. Alternatively, coolant from the second coolant circuit may remain in the second coolant jacket.

[0174] Turning now to FIG. 8, it shows an operating sequence 800 graphically illustrating the methods 500 and 600 being implemented on the system 100 of FIG. 2 and EGR cooler 142 of FIGS. 2 and 3. Plot 810 illustrates a rate of EGR flow, plot 820 illustrates a first coolant temperature and line 822 illustrates an upper threshold coolant temperature, plot 830 illustrates a second coolant temperature, plot 840 illustrates an engine temperature, line 842 illustrates a threshold cold-start temperature, and line 844 illustrates a threshold friction temperature. Time increases from a left side of the figure to a right side of the figure. The first coolant temperature is indicative of a temperature of coolant in the first coolant jacket and the second coolant temperature is indicative of a temperature of coolant in the second coolant jacket.

[0175] Prior t1, a cold-start is occurring, as illustrated by the engine temperature being less than the threshold cold-start temperature (plots 840 and 842, respectively). As such, EGR flow is off, the first coolant temperature is low and the second coolant temperature is low.

[0176] At t1, the cold-start is complete as the engine temperature is greater than or equal to the threshold cold-start temperature. However, the engine temperature is less than the threshold friction temperature (line 844). This may indicate that engine oil is at a temperature less than a desired temperature and friction in the engine is greater than a desired amount. However, EGR may still be undesired at this point in the engine warm-up cycle. As such, coolant flows to the second coolant jacket by opening one or more valves. In the example of FIG. 1, one or more shut-off elements 7a and 7c are closed and one or more shut-off elements 7b and 7d are opened to allow coolant to flow to the second coolant jacket. In the example of FIG. 3, one or more of a degas inlet valve 344 and a radiator inlet line valve 352 are closed and one or more of the degas outlet valve 346 and radiator outlet line valve 354 are opened to flow coolant to the second coolant jacket. Additionally, coolant is delivered to the first coolant jacket when coolant from the second coolant circuit flows to the second coolant jacket. Coolant may flow to the first coolant jacket when at least a first coolant inlet line valve 318 and the first coolant outflow line valve 314 is closed, in the example of FIG. 3. As such, first coolant fills the first coolant jacket and second coolant fills the second coolant jacket. Exhaust gas does not flow through the EGR cooler, but is still able to heat the second coolant in the second coolant jacket. As the second coolant warms-up, it is able to heat up the first coolant in the first coolant jacket.

[0177] After t1 and prior to t2, the second coolant temperature continues to increase as exhaust gas flows by and thermally communicates with the second coolant jacket. The second coolant thermally communicates with the first coolant in the first coolant jacket, thereby increasing a temperature of the first coolant. The engine temperature continues to increase. This may be assisted by flowing the warm first coolant to the engine, where engine oil among other engine components (e.g., a cooling sleeve in a combustion chamber) are heated by the first coolant from the first coolant jacket. EGR remains off.

[0178] At t2, the engine temperature is substantially equal to threshold friction temperature. As such, second coolant is no longer delivered to the second coolant jacket. In one example, the second coolant jacket is filled with air. This may occur by one or more shut-off elements 7a and 7c being opened and one or more shut-off elements 7b and 7d being closed to allow air to flow to the second coolant jacket, in the example of FIG. 1. In the example of FIG. 3, one or more of a degas inlet valve 344 and a radiator inlet line valve 352 are opened and one or more of the degas outlet valve 346 and radiator outlet line valve 354 are closed to flow air to the second coolant jacket. In this way, the air in the second coolant jacket thermally insulates the first coolant jacket from exhaust gas in the exhaust passage. First coolant may continue to flow through the first coolant circuit since EGR is activated. In one example, EGR is demanded to decrease NO.sub.x emissions from the engine.

[0179] After t2 and prior to t3, EGR continues to flow through the EGR cooler, thereby increasing a temperature of the first coolant toward the upper threshold coolant temperature. The second coolant temperature continues to decrease as the second coolant remains in one or more of the degas bottle, radiator, and/or a container. The engine temperature continues to slightly increase, but at a rate less than a rate of temperature increase prior to t2. This may be due to the EGR flow.

[0180] At t3, the EGR continues to flow due to engine demand. As a result, the first coolant temperature exceeds the upper threshold coolant temperature. In response, the second coolant flows to the second coolant jacket. In this way, the second coolant may cool the first coolant and prevent the first coolant from boiling due to exposure to hot exhaust gas.

[0181] After t3 and prior to t4, the EGR remains active. The first coolant temperature begins to decrease to a temperature less than the upper threshold coolant temperature. The second coolant temperature begins to correspondingly increase as heat is transferred from the first coolant jacket to the second coolant jacket. As such, EGR continues to be cooled and flow to the engine without overheating of one or more of the coolants.

[0182] At t4, the EGR is deactivated in response to EGR demand being absent. As such, the first coolant may flow to other portions of the first coolant circuit (e.g., a combustion chamber cooling sleeve 114 of FIG. 2). The second coolant no longer flows to the second coolant jacket as the first coolant temperature is less than the upper threshold coolant temperature and exhaust heat energy is not demanded.

[0183] In this way, exhaust gas heat may be utilized without flowing exhaust gas through an EGR cooler. First and second coolant jackets of the EGR cooler are coupled to separate first and second coolant circuits, respectively. Additionally, the second coolant jacket contacts exhaust gas in the exhaust passage and serves as a barrier between the first coolant jacket and exhaust gas in the exhaust gas passage. The technical effect of thermally coupling the second coolant jacket to exhaust gas in the exhaust gas passage is to flow coolant from the second coolant circuit to the second coolant jacket when heating is desired and EGR is not. By doing this, engine efficiency may be increased.

[0184] An embodiment of a forced-induction internal combustion engine having at least one cylinder, an intake system for supplying the at least one cylinder with charge air, an exhaust system for discharging the exhaust gases, and an exhaust gas recirculation system, which has a recirculation line which, while forming a junction, branches off from the exhaust system and opens into the intake system, wherein a cooler is arranged in the recirculation line, which cooler has a core, which conducts coolant, is incorporated into a first coolant circuit and serves to transfer heat between the exhaust gas and the coolant, and where the cooler projects into the exhaust system in the region of the core, and at least one coolant jacket, which conducts coolant, is provided in the cooler, said jacket being arranged between the core conducting coolant and the exhaust system conducting exhaust gas and being incorporated into a second coolant circuit, wherein, to form the second coolant circuit, the at least one coolant jacket has a discharge line for discharging the coolant and a supply line for supplying the coolant. A first example of the engine further comprising where the coolant of the second coolant circuit is stored in a container, which is at least connectable to the at least one coolant jacket of the second coolant circuit via the discharge line and via the supply line. A second example of the engine, optionally including the first example, further includes where a bypass line for bypassing the container is provided, said bypass line branching off from the discharge line and opening into the supply line, and where the bypass line further comprises a heat exchanger. A third example of the engine, optionally including the first and/or second examples, further includes where the bypass line comprises a third shutoff element upstream of the heat exchanger and a fourth shutoff element downstream of the heat exchanger. A fourth example of the engine, optionally including one or more of the first through third examples, further includes where in the discharge line comprises a first shutoff element, the supply line comprises a second shutoff element, and where the second coolant circuit comprises a pump arranged in the discharge line. A fifth example of the engine, optionally including one or more of the first through fourth examples, further includes where the junction is located directly downstream of an aftertreatment device. A sixth example of the engine, optionally including one or more of the first through fifth examples, further includes where the aftertreatment device is one or more of a particulate filter, oxidation catalyst, and a combination thereof. A seventh example of the engine, optionally including one or more of the first through sixth examples, further includes where the exhaust gas recirculation system comprises a shutoff element, and where the shutoff element is located downstream of the cooler. A eighth example of the engine, optionally including one or more of the first through seventh examples, further includes where a bypass line for bypassing the cooler. A ninth example of the engine, optionally including one or more of the first through eighth examples, further includes where a controller with computer-readable instructions stored thereon that when executed enable the controller to flow coolant from a coolant circuit not coupled to the engine to at least one coolant jacket of the cooler during a warm-up phase of the engine.

[0185] An embodiment of a method, comprising flowing coolant from a first coolant circuit to a first coolant jacket of an exhaust gas recirculation cooler, flowing coolant from a second coolant circuit to a second coolant jacket of the exhaust gas recirculation cooler, and heating coolant in the first coolant jacket with coolant in the second coolant jacket when exhaust gas recirculation is deactivated. A first example of the method further includes where the first coolant circuit is fluidly coupled to an engine when a first coolant outflow valve is open and an engine inlet line valve is open. A second example of the method, optionally including the first example, further includes where flowing coolant from the second coolant circuit to the second coolant jacket occurs following a cold-start. A third example of the method, optionally including the first and/or second examples, further includes where flowing coolant from the second coolant circuit to the second coolant jacket occurs when a coolant temperature in the first coolant jacket is greater than or equal to an upper threshold temperature. A fourth example of the method, optionally including one or more of the first through third examples, further includes where flowing coolant from the second coolant circuit to the second coolant jacket occurs when an amount of condensate in an EGR cooler is greater than or equal to a threshold condensate amount.

[0186] An embodiment of a system comprising an EGR cooler arranged in an EGR passage, where the cooler comprises a first coolant jacket hermetically sealed from a second coolant jacket, and where a portion of the cooler comprising the second coolant jacket protrudes into a portion of an exhaust passage directly downstream of an aftertreatment device. A first example of the system further includes where the first coolant jacket is fluidly coupled to a first coolant circuit, the first coolant circuit being fluidly coupled to an engine, and where the second coolant jacket is fluidly coupled to a second coolant circuit. A second example of the system optionally including the first example further includes where the second coolant jacket is located between the exhaust passage and the first coolant jacket. A third example of the system, optionally including the first and/or second examples further includes where the second coolant jacket is in direct thermal communication with exhaust gas in the exhaust passage and where the first coolant jacket is in direct thermal communication with exhaust gas in the EGR cooler. A fourth example of the system, optionally including one or more of the first through third examples, further includes where a controller with computer-readable instructions that when executed enable the controller to flow coolant from the second coolant circuit to the second coolant jacket when EGR is not desired, and flow air from the second coolant circuit to the second coolant jacket when exhaust heat energy is not desired.

[0187] Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations, and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations, and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system, where the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with the electronic controller.

[0188] It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.

[0189] The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.