Method and system for energy recovery via EGR cooler

Abstract

The present invention relates to methods and systems for energy recovery via an EGR cooler. Methods and systems for an EGR cooler including a phase change material are provided. In one example, when the engine is deactivated, exhaust gas is routed through the EGR cooler to maintain engine temperature.

Description

Technical Field

[0001] The present description generally relates to an exhaust gas recirculation (EGR) arrangement comprising at least one recirculation line having an EGR cooler. Background Art

[0002] The internal combustion engine of the present description can be used as a motor vehicle drive unit. In the context of the present disclosure, the expression "internal combustion engine" covers diesel engines and Otto cycle engines, but also covers hybrid internal combustion engines, that is, internal combustion engines operated by a hybrid combustion process, and hybrid drive devices that include at least one further torque source for driving the motor vehicle in addition to the internal combustion engine, such as an electric machine that can be drivingly connected to the internal combustion engine and outputs power instead of the internal combustion engine or in addition to the internal combustion engine.

[0003] In the development of internal combustion engines, a constant search is made to minimize fuel consumption. In addition, a search is made to reduce pollutant emissions in order to be able to comply with future limit values ​​for pollutant emissions.

[0004] Internal combustion engines can be equipped with a supercharging device, wherein supercharging is associated with a method for increasing power in which the charge air used for the combustion process in the engine is compressed, as a result of which a greater mass of charge air can be supplied to each cylinder per working cycle. In this way, the fuel mass and therefore the average pressure can be increased.

[0005] Supercharging can be a suitable method for increasing the power of an internal combustion engine while maintaining a constant scavenging volume or for reducing the scavenging volume while maintaining the same power. In most cases, supercharging leads to an increase in volumetric power output and a more favorable power-to-weight ratio. If the scavenging volume is reduced, the loads can be collectively shifted to higher loads, at which higher loads the fuel consumption rate is lower, given the same vehicle boundary conditions. Supercharging of an internal combustion engine can unexpectedly assist efforts to minimize fuel consumption, that is, to improve the efficiency of the internal combustion engine.

[0006] Suitable transmission configurations may additionally allow downshifting, thereby also achieving lower specific fuel consumption. In the case of downshifting, there is the fact that specific fuel consumption is generally lower at low engine speeds, particularly in the presence of relatively high loads.

[0007] By configuring the supercharging in a targeted manner, advantages can also be achieved with regard to exhaust emissions. By suitable supercharging of diesel engines, for example, nitrogen oxide emissions can be reduced without any loss of efficiency. At the same time, hydrocarbon emissions can be positively influenced. CO2 emissions, which are directly related to fuel consumption, are also reduced as fuel consumption is reduced.

[0008] However, in order to comply with future limit values ​​for pollutant emissions, further measures may be necessary. One example may include nitrogen oxides, where the reduction of nitrogen oxide emissions is highly relevant in particular in diesel engines. Since the formation of nitrogen oxides is not only accompanied by excess air but also by high temperatures, one concept for reducing nitrogen oxide emissions consists in using a combustion process with lower combustion temperatures.

[0009] Here, exhaust gas recirculation (EGR), i.e., recirculation of combustion gases from the outlet side (e.g., exhaust system) to the inlet side (e.g., intake system) may be desirable to achieve this purpose, wherein the emission of nitrogen oxides may be reduced by increasing the exhaust gas recirculation rate. Here, the exhaust gas recirculation rate x EGR Determined as x EGR =m EGR / (m EGR +m fresh air ), where m EGR represents the mass of the recirculated exhaust gas, and m fresh air Indicates the fresh air supplied. Oxygen supplied by exhaust gas recirculation may be considered.

[0010] In order to significantly reduce nitrogen oxide emissions, high exhaust gas recirculation rates can be used, which can be x EGR ≈60% to 70% or more. Such a high recirculation rate may require cooling of the exhaust gas for recirculation, thereby reducing the temperature of the exhaust gas and increasing the density of the exhaust gas, so that a larger mass of exhaust gas can be recirculated. Therefore, the exhaust gas recirculation device can be equipped with a cooler. The exhaust gas recirculation device of the internal combustion engine to which the present disclosure relates includes a cooling device, namely at least one EGR cooler, which has a coolant-conducting coolant jacket for transferring heat between the exhaust gas and the coolant.

[0011] Problems may arise during the introduction of the recirculated exhaust gas into the intake system if the temperature of the recirculated hot exhaust gas decreases and condensate forms.

[0012] Firstly, condensate forms if the recirculated hot exhaust gas meets and mixes with the cold fresh air in the intake system. The exhaust gas cools down, while the temperature of the fresh air increases. The temperature of the mixture of fresh air and recirculated exhaust gas, i.e. the temperature of the combustion air, is lower than the exhaust gas temperature of the recirculated exhaust gas. During the cooling of the exhaust gas, liquids, in particular water, which were previously contained in the exhaust gas and / or in the combustion air which is still in a gaseous state, condense out if the dew point temperature of the components of the gaseous combustion air flow undershots. Condensate formation occurs in the free combustion air flow, wherein the pollutants in the combustion air usually form the starting point for the formation of condensate droplets.

[0013] Second, because the temperature of the inner walls of the intake system may be below the dew point temperature of the relevant gas components, condensate may form when the recirculated hot exhaust gas and / or combustion air impinges on the inner walls of the intake system.

[0014] Condensate and condensate droplets can be undesirable and lead to increased noise emissions in the intake system and can collide with the impeller blades of a compressor wheel of a supercharger or exhaust gas turbocharger arranged in the intake system. The latter effect is associated with a reduction in compressor efficiency and can degrade the impeller blades.

[0015] With regard to the above-mentioned problem of condensate formation, an EGR cooler may also be advantageous or helpful. Cooling of the exhaust gas for recirculation during recirculation has the advantageous effect that condensate is not formed for the first time in the intake system but already during recirculation and can be separated out during recirculation.

[0016] A disadvantage of EGR coolers according to the prior art is that, due to the principle involved, useful exhaust gas energy, i.e. the heat that can be extracted from the exhaust gas in the cooler by the coolant, is only available and usable when the exhaust gas is being recirculated. If the exhaust gas recirculation device has been deactivated, so that no exhaust gas is being recirculated, the exhaust gas energy of the hot exhaust gas generally remains unutilized. Further efficiency advantages could be achieved in internal combustion engines if this exhaust gas energy could be utilized without restriction, that is to say recovered in the case of energy recovery.

[0017] For example, the energy of the hot exhaust gas can be used to reduce friction losses and thus reduce the fuel consumption of the internal combustion engine. In this context, a rapid warming of the engine oil by the exhaust gas heat, in particular after a cold start, can be advantageous. Rapid warming of the engine oil during the warm-up phase of the internal combustion engine ensures a correspondingly rapid reduction in the viscosity of the oil and thus reduces friction and friction losses, in particular in bearings supplied with oil, such as the bearings of a crankshaft.

[0018] Here, the oil can be actively warmed, for example, by a heating device. For this purpose, a coolant-operated oil cooler can be used during the warm-up phase, which is contrary to its intended purpose of warming the oil.

[0019] Rapid warming of the engine oil in order to reduce friction losses can also be promoted substantially by rapid heating of the internal combustion engine itself, which in turn is assisted, ie promoted, since as little heat as possible is extracted from the internal combustion engine during the warm-up phase.

[0020] In this respect, in the case of a liquid-cooled internal combustion engine, it is also advantageous to supply heat to the coolant of the engine cooling device, in particular in the warm-up phase or after a cold start. The exhaust gas energy can be used to warm the coolant of the engine cooling device.

[0021] A previous example shown in the German publication DE 10 2008 020 408 A1 describes an internal combustion engine in which the exhaust energy can be used even when no exhaust gas is recirculated. That is to say, the exhaust energy can be used even when no exhaust gas is taken from the intake system and introduced into the exhaust gas discharge system. The return line can be optionally connected to the intake system and / or the exhaust gas discharge system downstream of the EGR cooler using a control valve, which also serves as an EGR valve. Even when the exhaust gas recirculation device is deactivated and no exhaust gas is recirculated, the exhaust energy from the hot gases can be used for energy recovery. The recovered energy is used to heat the engine oil faster after a cold start and in this way reduce friction losses, or to heat the passenger compartment.

[0022] EGR coolers according to the prior art may also have the disadvantage that the cooler does not have to be configured with respect to effective energy recovery, but rather focuses on the cooling of the exhaust gas, i.e. a pure cooling effect. Here, the cooler is able to cope with all exhaust gas flow rates that are recirculated through the exhaust gas recirculation device during operation of the internal combustion engine. In particular, the cooler can be configured to provide cooling to the maximum exhaust gas flow rate that is recirculated. The range of variations in the exhaust gas flow rate that is recirculated through the exhaust gas recirculation device leads to widely varying pressure conditions at the cooler. The pressure gradient across the cooler varies significantly in a manner that depends on the recirculated exhaust gas flow rate, that is to say in such a correlated manner that the control or setting of the recirculation rate can be taken into account. The resulting interaction leads to certain dynamics and requires correspondingly complex or intricate control of the exhaust gas recirculation device. Summary of the invention

[0023] The inventors herein have recognized potential problems with such systems and have proposed methods to at least partially address these problems. In one example, the above problems can be addressed by a method that includes: during engine deactivation, flowing exhaust gas heated via an EGR cooler disposed along a recirculation line to an intake system and heating the exhaust gas via the EGR cooler. In this way, EGR can flow to the engine during engine deactivation even if there is no EGR request.

[0024] As an example, by intrusively flowing EGR during engine deactivation, an EGR cooler can heat the EGR through a phase change material. Heat can be recovered from the exhaust gas during combustion conditions of the engine, where the heat can be released to the EGR during engine deactivation if desired. By doing so, engine temperature can be maintained, which can reduce friction losses and improve fuel economy.

[0025] It should be understood that the above summary is provided to introduce some concepts further described in the detailed description in a simplified form. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is solely defined by the appended claims. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A first embodiment of an internal combustion engine and an exhaust gas recirculation arrangement is schematically shown.

[0027] Figure 2 A first embodiment of an internal combustion engine and an exhaust gas recirculation arrangement is schematically shown in a first operating mode.

[0028] Figure 3 A first embodiment of an internal combustion engine and an exhaust gas recirculation arrangement is schematically shown in a second operating mode.

[0029] Figure 4 The first embodiment of an internal combustion engine and an exhaust gas recirculation arrangement is schematically shown in a third operating mode.

[0030] Figure 5 A high level flow chart of a method for selecting between a first mode of operation, a second mode of operation, and a third mode of operation is shown.

[0031] Fig. 6A A method for executing a first mode of operation is shown.

[0032] Figure 6B A method for executing the second mode of operation is shown.

[0033] Figure 6C A method for executing the third mode of operation is shown.

[0034] Figure 7 A schematic diagram of an engine for a hybrid vehicle is shown.

[0035] Figure 8 shows a diagram illustrating the combination Figure 1 and Figure 7 The engine performs Fig. 6A , Figure 6B and Figure 6C The method of engine operation sequence.

[0036] Fig.9A , Fig. 9B , Fig. 9C , Fig.9D and Fig.9E Various operating modes of a second embodiment of an internal combustion engine are shown, wherein the second embodiment comprises a first cooler and a second cooler. DETAILED DESCRIPTION

[0037] The following description relates to systems and methods for an EGR cooler including a phase change material configured to heat and cool exhaust gas. Figure 1 An embodiment of an internal combustion engine is shown. Figure 2 An internal combustion engine is shown operating in a first mode. Figure 3 The internal combustion engine is shown operating in a second mode. Figure 4 The internal combustion engine is shown operating in a third mode. Figure 5 A high level flow chart for selecting between a first mode of operation, a second mode of operation, and a third mode of operation is shown. Fig. 6A A method for executing a first mode of operation is shown. Figure 6B A method for executing the second mode of operation is shown. Figure 6C A method for executing the third mode of operation is shown. Figure 7 A schematic diagram of an engine in a hybrid vehicle is shown. Figure 7 The engine can be similar to Figure 1 engine. Figure 8 Show combination Figure 1 and Figure 7 The engine performs Figure 5 , Fig. 6A , Figure 6B and Figure 6C The method of engine operation sequence.

[0038] Fig.9A , Fig. 9B , Fig. 9C , Fig.9D and Fig.9E Various operating modes of a second embodiment of an internal combustion engine are shown, wherein the second embodiment includes a first cooler and a second cooler. In one example, the first cooler can be a cooler dedicated to cooling the EGR, and the second cooler can be a cooler dedicated to heat recovery. In some operating modes, the first cooler and the second cooler can be operated in series to provide an increased amount of cooling to the EGR while recovering heat. Additionally or alternatively, both the first cooler and the second cooler can be used for heat recovery.

[0039] Figure 1-Figure 4 , Figure 7 and 9A to 9E An example configuration with relative positioning of various components is shown. If shown to be in direct contact or directly connected to each other, these elements can be referred to as direct contact or directly connected, respectively, at least in one example. Similarly, at least in one example, the elements shown as adjacent or adjacent to each other can be adjacent or adjacent to each other, respectively. As an example, the components placed in coplanar contact with each other can be referred to as coplanar contact. As another example, in at least one example, the elements with only space between them and no other components can be so called. As another example, the elements shown above / below each other, on the opposite sides or on the left / right sides of each other can be so called relative to each other. In addition, as shown in the accompanying drawings, in at least one example, the topmost element or the topmost point of the element can be referred to as the "top" of the component, and the bottommost element or the bottommost point of the element can be referred to as the "bottom" of the component. As used herein, top / bottom, up / down, above / below can be relative to the vertical axis of the accompanying drawings and used to describe the positioning of the elements of the accompanying drawings relative to each other. In this way, in one example, the element shown as above other elements is vertically positioned above other elements. As yet another example, the shapes of elements depicted in the accompanying drawings may be referred to as having those shapes (e.g., such as circular, straight, flat, curved, rounded, chamfered, angled, etc.). In addition, in at least one example, elements shown as crossing each other may be referred to as crossing elements or crossing each other. In addition, in one example, elements shown as being inside another element or outside another element may be referred to as such. It should be understood that one or more components referred to as "substantially similar and / or identical" differ from each other according to manufacturing tolerances (e.g., within a deviation of 1-5%).

[0040] As another example, the above problem can be solved by an internal combustion engine, which has: at least one cylinder, an intake system for supplying air to the at least one cylinder, an exhaust exhaust system for exhausting exhaust gas, and an exhaust gas recirculation device including at least one recirculation line, wherein at least one cooler and at least one control element are arranged in the at least one recirculation line for setting a predeterminable exhaust gas flow rate for recirculation, and at least one cooler is equipped with a phase change material, wherein the phase change material exists in a liquid phase or a solid phase depending on the material temperature, and stores heat as the material temperature increases and emits the stored heat again as the material temperature decreases.

[0041] In an internal combustion engine according to the disclosure, at least one cooler of the exhaust gas recirculation system is equipped with a phase change material, wherein several coolers can also be produced from this material.

[0042] The phase change material can extract heat from the hot exhaust gas conducted through the cooler and thus act as an additional heat sink, but also as an energy storage. In other words, a cooler equipped with a phase change material according to the present disclosure can extract more energy from the exhaust gas than a conventional cooler using only coolant. This provides advantages in the case of large exhaust gas volumes occurring at high engine speeds or loads (and especially at high exhaust gas temperatures occurring at high loads).

[0043] Compared to conventional coolers, the cooler equipped with phase change material according to the present disclosure has further significant advantages. When needed, the phase change material can return stored energy extracted from the exhaust gas to the exhaust gas. In this way, during some engine conditions where the exhaust gas temperature is lower than the temperature of the cooler, the cooler can be used as a heater.

[0044] The advantageous effect of such a facility of a cooler is that, for example, it can relieve the cooling of the inoperative internal combustion engine in overrun mode and / or fuel cut-off mode. The exhaust gas taken from the exhaust gas discharge system is further heated when it passes through the cooler and is supplied to the cylinders of the inoperative internal combustion engine through the intake system, thereby at least partially offsetting the cooling. When restarting or re-igniting the internal combustion engine, the operating temperature is reached faster than usual, which has advantages in terms of efficiency and pollutant emissions. In some examples, the operating temperature can be maintained during the entire duration of the fuel cut-off mode.

[0045] Furthermore, advantages arise when the internal combustion engine is switched off, for example when the vehicle is parked. When the internal combustion engine is started again, the internal combustion engine can be heated up more quickly, in particular by using recirculated exhaust gas to heat the intake air, thereby again achieving advantages in terms of efficiency and pollutant emissions.

[0046] This effect will become increasingly important since one concept for reducing fuel consumption consists in deactivating the internal combustion engine when there is no instantaneous power demand, instead of continuing idling operation (start-stop strategy). This can consist in deactivating cylinders so that they are no longer supplied with fuel.

[0047] Another application is stop-and-go traffic, such as encountered in traffic jams on freeways and highways. Stop-and-go traffic is ubiquitous in city center traffic due to the presence of uncoordinated traffic signals and increased traffic volumes.

[0048] The exhaust gas energy recovered using the coolant in the cooler can be used, for example, during the warm-up phase or after a cold start to warm the engine oil of the internal combustion engine and thus reduce the friction losses of the internal combustion engine. In the case of a liquid-cooled internal combustion engine, the exhaust gas energy can be used to warm the coolant of the engine cooling device and thus accelerate the heating of the internal combustion engine. Both measures improve or increase the efficiency of the internal combustion engine.

[0049] At least one EGR cooler of an internal combustion engine according to the present disclosure is configured both with regard to effective cooling and energy recovery, ie utilizing exhaust gas energy. According to the present disclosure, methods for both are described below.

[0050] The at least one recirculation line of the exhaust gas recirculation system according to the present disclosure may belong to the low-pressure EGR or the high-pressure EGR.

[0051] Several coolers can be provided, for example arranged in parallel, which are switched on in sequence and used to cool the exhaust gas to be recirculated. In this way, the cooling power of the EGR cooling device or the number of EGR coolers can be adapted to the exhaust gas flow rate for cooling. This has a number of beneficial effects, which will be described below.

[0052] The pressure gradient across a single cooler varies to a lesser extent during operation of the cooler because the exhaust gas flow rate cooled or managed by the cooler varies to a lesser extent.

[0053] In the case of relatively low recirculation rates, according to the disclosure, one cooler can be used to cool the exhaust gas for recirculation. If the exhaust gas flow rate for recirculation and for cooling then increases, for example in the case of exceeding a threshold exhaust gas flow rate, a further cooler can be activated in order to cool the exhaust gas and contribute to cooling the exhaust gas for recirculation. Depending on the number of EGR coolers provided, the activation can be performed several times or continuously if, for example, three, four or more coolers are provided. The control or adjustment of the recirculation rate reacts less dynamically.

[0054] Embodiments of the internal combustion engine may further include those in which the cooler forms an integral structural unit. A prefabricated assembly including the cooler and constituting the entire cooling unit simplifies the installation of the exhaust gas recirculation device and the internal combustion engine as a whole and thus also reduces costs.

[0055] Embodiments of the internal combustion engine may further include the cooler in the form of individual coolers. According to the modular principle, the individual coolers can be used to form different exhaust gas recirculation devices or to equip different internal combustion engines.

[0056] Embodiments of the internal combustion engine may further include wherein a charging arrangement is provided.

[0057] A cooler according to the present disclosure may include at least one cavity or at least one container for receiving a phase change material. The cavity or container for receiving the phase change material may be formed as an integral part / integral part of the cooler during the production process. The cooler may be constructed in a modular manner, wherein a cavity for receiving the phase change material is formed during assembly.

[0058] The cavity may be formed wherein the cooler itself is provided with a housing such that the cavity containing the phase change material is formed between the cooler and at least one housing element arranged spaced therefrom. The cooler extending from the housing then comprises a container for receiving the phase change material.

[0059] Embodiments of the internal combustion engine may further include wherein the at least one cooler includes at least one cavity for receiving the phase change material. Embodiments of the internal combustion engine may further include wherein the at least one cavity is formed using at least one housing element.

[0060] The at least one cooler may not be a cast part in which the at least one cavity is formed as an integral component during the casting process. Instead, the cooler may be an assembled system, for example made of sheet metal, in which the at least one cavity is formed during the assembly process using housing elements arranged spaced apart from each other.

[0061] Embodiments of the internal combustion engine may further include, wherein for the purpose of energy recovery, at least one cooler has at least one coolant conduction cooling jacket for transferring heat between the exhaust gas and the coolant.

[0062] Embodiments of the internal combustion engine may further include a first recirculation line in which a first cooler is arranged and in which the first recirculation line is connectable to at least the exhaust gas discharge system upstream of the first cooler and to at least the intake system downstream of the first cooler using at least one control element.

[0063] In this case, embodiments of the internal combustion engine may further include, wherein the first recirculation line downstream of the first cooler is at least selectively connectable to an intake system and / or to an exhaust gas discharge system using at least one control element.

[0064] In the case of the present embodiment, the exhaust energy of the hot exhaust gas can be utilized even when the exhaust gas recirculation device has been deactivated, namely with the aid of a first cooler which can be selectively connected downstream of the intake system and / or the exhaust gas discharge system, wherein at least one control element is used for this purpose, by means of which the exhaust gas conduction line can be switched accordingly, i.e. connected to the exhaust gas discharge system.

[0065] Therefore, even when the exhaust gas recirculation device has been deactivated, heat can be transferred from the exhaust gas to the coolant and the phase change material of the first cooler, wherein the coolant flowing through the first cooler removes heat from the interior of the first cooler and supplies heat for a predetermined duration, or the phase change material stores heat extracted from the exhaust gas, thereby improving the efficiency of the internal combustion engine. In this regard, the exhaust energy inherent in the exhaust gas can be utilized.

[0066] Embodiments of the internal combustion engine may further include those wherein the first recirculation line branches off from the exhaust-gas discharge system so as to form a first junction point and opens into the intake system so as to form a second junction point.

[0067] In this case, embodiments of the internal combustion engine may further include wherein a first control element is provided in the first recirculation line at the second junction.

[0068] The first control element serves as an EGR valve and, when the exhaust gas recirculation device is active, is used to adjust the recirculation rate, i.e. the amount of exhaust gas recirculated through the first recirculation line. The use of a combined valve arranged at the second junction allows the recirculated exhaust gas flow rate to be dimensioned and the intake fresh air flow rate to be throttled simultaneously.

[0069] A combined valve of the type described can be, for example, a flapper pivotable about an axis extending transversely to the fresh air flow, so that in a first end position the front side of the flapper blocks the intake system and simultaneously opens the recirculation line, and in a second end position the rear side of the flapper covers the recirculation line and simultaneously opens the intake system. An additional valve body connected and therefore mechanically coupled to the flapper opens or blocks the recirculation line. Whereas the flapper serves to regulate the air flow rate supplied through the intake system, the valve body effects a metering of the exhaust gas flow rate that is recirculated.

[0070] Embodiments of the internal combustion engine may further include wherein an exhaust gas conduction line is provided which branches off from the first recirculation line downstream of the first cooler so as to form a third junction point and opens into the exhaust gas discharge system so as to form a fourth junction point.

[0071] In this case, an embodiment of the internal combustion engine may further include a second control element disposed at a fourth junction. The second control element may be used to connect the first cooler downstream to the exhaust gas discharge system. The first cooler does not cool any exhaust gas for recirculation. Instead, the first cooler cools the exhaust gas extracted from the exhaust gas discharge system and reintroduces it into the exhaust gas discharge system. That is, in the present case, the first cooler is only used for energy recovery (e.g., for making the energy inherent in the exhaust gas available later).

[0072] Embodiments of the internal combustion engine may further include the one in which the second control element is a 3 / 3-way directional control valve (3 / 3-way directional control valve) having three line connections and three switching positions.

[0073] Here, an embodiment of the internal combustion engine may further comprise an exhaust gas discharge system in which the fourth junction point is arranged downstream of the first junction point. In this embodiment, by adjusting the second control element towards the closed position, the exhaust gas back pressure upstream of the fourth junction point can be increased in a targeted manner, and thus the exhaust gas back pressure at the inlet of the exhaust gas recirculation system can also be increased in a targeted manner.

[0074] This allows to increase the propulsion pressure gradient across the cooler. The possibility of exhaust gas escaping around the cooler (eg bypassing the cooler) is now hindered.

[0075] In order to generate the desired pressure gradient, a shut-off element can also be provided upstream of the point at which the exhaust gas recirculation device opens into the intake system, in order to reduce the pressure downstream of the shut-off element on the inlet side.

[0076] Embodiments of the internal combustion engine may further include wherein at least one compressor drivable by an auxiliary drive is arranged in the intake system.

[0077] Advantages of a compressor that can be driven by an auxiliary drive (i.e. a supercharger) over an exhaust gas turbocharger include that the supercharger can generate and provide the desired boost pressure during more conditions and, in some examples, independently of the operating state of the internal combustion engine. This applies in particular to superchargers that can be driven electrically by an electric machine and therefore independently of the rotational speed of the crankshaft.

[0078] In the previous example, it was particularly difficult to achieve a power increase in the entire engine speed range by exhaust gas turbocharging. Below a certain engine speed, a relatively severe torque drop was observed. This torque drop is understandable because the charge pressure ratio depends on the turbine pressure ratio or the turbine power. If the engine speed is reduced, this leads to a smaller exhaust mass flow and thus to a lower turbine pressure ratio or a lower turbine power. Therefore, for lower engine speeds, the charge pressure ratio also decreases. This is equivalent to a torque drop.

[0079] Embodiments of the internal combustion engine may further include that at least one exhaust gas turbocharger is provided, the exhaust gas turbocharger comprising a turbine arranged in the exhaust gas discharge system and a compressor arranged in the intake system. In the exhaust gas turbocharger, the compressor and the turbine are arranged on the same shaft. The hot exhaust gas flow is fed to the turbine and expands in the turbine and releases energy, whereby the shaft is set to rotate. The energy supplied to the shaft by the exhaust gas flow is used to drive the compressor, which is also arranged on the shaft. The compressor delivers and compresses the charge air fed to it, thereby achieving the supercharging of the cylinder. A charge air cooler is advantageously arranged in the intake system downstream of the compressor, by which the compressed charge air is cooled before entering at least one cylinder. The cooler reduces the temperature of the charge air and thereby increases the density of the charge air, so that the cooler also contributes to improving the charge of the cylinder, that is to say to a greater air quality. In fact, compression occurs by cooling.

[0080] Advantages of an exhaust gas turbocharger relative to a supercharger may include that the exhaust gas turbocharger utilizes the exhaust energy of the hot exhaust gas, whereas the supercharger draws the energy required to drive it directly or indirectly from the internal combustion engine and therefore, at least as long as the driving energy does not come from an energy recovery source, the efficiency is adversely affected (i.e., reduced).

[0081] If the supercharger is not a supercharger that can be driven by an electric machine, that is to say is driven electrically, a mechanical or kinematic connection for power transmission is usually required between the supercharger and the internal combustion engine, which can also adversely affect or determine the packaging in the engine compartment.

[0082] In order to be able to counteract the torque drop at low engine speeds, an embodiment of the internal combustion engine may further include providing at least two exhaust gas turbochargers therein. Specifically, if the engine speed decreases, this results in a smaller exhaust gas mass flow and thus a lower charge pressure ratio.

[0083] By using a plurality of exhaust-gas turbochargers, for example a plurality of exhaust-gas turbochargers connected in series or in parallel, the torque characteristics of a supercharged internal combustion engine can be improved.

[0084] In order to improve the torque characteristics, in addition to the at least one exhaust-gas turbocharger, a further compressor may be provided, in particular a supercharger which can be driven by an auxiliary drive or a compressor of a further exhaust-gas turbocharger.

[0085] In this case, embodiments of the supercharged internal combustion engine may further comprise an intake system in which at least one recirculation line opens into the intake system downstream of the compressor.

[0086] In the case of a high-pressure EGR arrangement, the exhaust gas is introduced into the intake system downstream of the compressor. Here, in order to provide or ensure the pressure gradient required for recirculation between the exhaust gas discharge system and the intake system, in the case of an exhaust gas turbocharger, the exhaust gas is preferably and usually extracted from the exhaust gas discharge system upstream of the associated turbine. High-pressure EGR has the advantage that the exhaust gas does not pass through the compressor and therefore does not have to be subjected to exhaust gas aftertreatment before recirculation, for example in a particulate filter. There is no risk that deposits in the compressor change the geometry of the compressor, in particular the flow cross section, and thereby impair the efficiency of the compressor. Condensate formation can occur downstream of the compressor, which also heats the charge air supplied to it during the compression process and thereby prevents or counteracts the formation of condensate.

[0087] In this case, embodiments of the supercharged internal combustion engine may further comprise an intake system in which at least one recirculation line opens into the intake system upstream of the compressor.

[0088] During operation of an internal combustion engine with exhaust-gas turbocharging and simultaneous use of a high-pressure EGR device, conflicts can occur when recirculated exhaust gas is extracted from the exhaust-gas discharge system upstream of the turbine and is no longer used to drive the turbine.

[0089] In the case of an increase in the exhaust gas recirculation rate, the exhaust gas flow introduced into the turbine is simultaneously reduced. The reduced exhaust gas mass flow through the turbine leads to a lower turbine pressure ratio, as a result of which the charge pressure ratio also drops, which is equivalent to a smaller compressor mass flow. In addition to the reduced charge pressure, problems with regard to the surge limit may also arise in the operation of the compressor. Disadvantages may also arise in terms of pollutant emissions, such as the formation of soot during acceleration in the case of diesel engines.

[0090] For this reason, concepts are needed which ensure a sufficiently high charge pressure with a high exhaust gas recirculation rate at the same time. One solution is low-pressure EGR, by means of which the exhaust gas which has already flowed through the turbine is recirculated into the intake system. For this purpose, a low-pressure EGR device extracts exhaust gas from the exhaust gas discharge system downstream of the turbine and conducts it into the intake system, preferably upstream of the compressor, in order to be able to achieve the pressure gradient required for the recirculation between the exhaust gas discharge system and the intake system.

[0091] The exhaust gas recirculated via the low-pressure EGR device is mixed with fresh air upstream of the compressor. The mixture of fresh air and recirculated exhaust gas produced in this way forms charge air, which is supplied to the compressor and compressed, wherein the compressed charge air is cooled downstream of the compressor in a charge air cooler.

[0092] As the exhaust gas is conducted through the compressor, the exhaust gas may be subjected to exhaust aftertreatment downstream of the turbine.A low-pressure EGR arrangement may also be combined with a high-pressure EGR arrangement.

[0093] For the reasons already stated, embodiments of the supercharged internal combustion engine may further comprise embodiments in which at least one recirculation line branches off from the exhaust-gas discharge system upstream of the turbine.

[0094] Embodiments of the supercharged internal combustion engine may further include a turbine of the exhaust gas turbocharger provided with a variable turbine geometry, which allows a wide adaptation of the operation of the internal combustion engine by adjusting the turbine geometry or the effective turbine cross section. Here, adjustable guide vanes for influencing the flow direction are arranged in the inlet region of the turbine. In contrast to the impeller blades of a rotating impeller, the guide vanes do not rotate with the shaft of the turbine.

[0095] If the turbine has a fixed, non-variable geometry, the guide vanes can be arranged in the inlet region not only to be stationary but also completely immovable, that is to say completely rigidly fixed if a guide device is provided. In the case of a variable geometry, on the other hand, the guide vanes are appropriately arranged to be stationary but not completely immovable, but rather rotatable about their axis, so that the incident flow onto the impeller blades can be influenced.

[0096] By adjusting the geometry of the turbine, the exhaust pressure upstream of the turbine can be influenced and thus the pressure gradient between the exhaust gas discharge system and the intake system and thus the recirculation rate of the high-pressure EGR device.

[0097] For the reasons already stated, embodiments of the supercharged internal combustion engine may further comprise embodiments in which at least one recirculation line branches off from the exhaust-gas discharge system downstream of the turbine.

[0098] In this case, embodiments of the supercharged internal combustion engine may further include wherein at least one exhaust gas aftertreatment system is arranged in the exhaust gas discharge system between the turbine and the at least one branched recirculation line. As the exhaust gas is conducted through the compressor, the exhaust gas is preferably subjected to exhaust gas aftertreatment downstream of the turbine.

[0099] Here, embodiments of the internal combustion engine may further include an exhaust gas aftertreatment system in which a particulate filter is provided as exhaust gas aftertreatment.

[0100] In order to minimize soot emissions, regenerative particulate filters are used in this case, which filter soot particles out of the exhaust gas and store them, which are intermittently burned off during the regeneration of the filter. When no catalyst carrier is present, the temperature required to regenerate the particulate filter is approximately 550° C. Therefore, additional measures are regularly used to ensure regeneration of the filter under all operating conditions.

[0101] Regeneration of the filter introduces heat into the exhaust gas and increases the exhaust gas temperature and thereby the exhaust gas enthalpy. Thus, energy-rich exhaust gas is available at the outlet of the filter, which exhaust gas can be used in a manner according to the present disclosure.

[0102] Embodiments of the supercharged internal combustion engine may further comprise an exhaust gas aftertreatment system in which an oxidation catalytic converter is provided as exhaust gas aftertreatment.

[0103] It is undeniable that at sufficiently high temperature levels and in the presence of sufficiently large amounts of oxygen, oxidation of unburned hydrocarbons and carbon monoxide occurs in the exhaust gas discharge system even without additional measures. However, due to the rapid drop in exhaust gas temperature in the downstream direction and, therefore, a rapid decrease in the reaction rate, the reaction is quickly stopped. Therefore, catalytic reactors are used, which use catalytic materials that ensure oxidation even at low temperatures. If nitrogen oxides are also to be reduced, this can be achieved in the case of Otto cycle engines by using a three-way catalytic converter.

[0104] Oxidation is an exothermic reaction, wherein the heat released increases the temperature and thus the enthalpy of the exhaust gas. Thus, a more energy-rich exhaust gas is available at the outlet of the oxidation catalytic converter. In this respect, the provision of an oxidation catalytic converter is beneficial and advantageous, in particular in terms of the utilization of the exhaust gas energy according to the present disclosure.

[0105] Embodiments of the internal combustion engine may further comprise wherein a bypass line for bypassing the at least one cooler is provided, the bypass line bypassing the EGR cooler and wherein exhaust gas recirculated via the exhaust gas recirculation device can be introduced, bypassing the cooler, into the intake system.

[0106] Bypassing the EGR cooling device may be beneficial, for example in order to prevent heat from being otherwise introduced into the liquid-type cooling device of the internal combustion engine. This approach is advantageous if the liquid-type cooling device of the internal combustion engine is already highly loaded, for example under full load. If an exhaust gas recirculation device is used during engine braking, it is also advantageous if the hot exhaust gas is recirculated without being cooled.

[0107] Embodiments of the internal combustion engine may further include those in which a liquid-type cooling device is provided to form an engine cooling device.

[0108] Here, embodiments of the internal combustion engine may further include, wherein at least one cylinder head of the internal combustion engine is provided with at least one cooling jacket, which is integrated in the cylinder head in order to form a liquid-type cooling device.

[0109] Liquid-type cooling may be necessary in the case of supercharged engines, since the thermal load of a supercharged engine is significantly higher than that of a conventional internal combustion engine. If the cylinder head has an integrated exhaust manifold, the thermal load of the cylinder head is higher than that of a conventional cylinder head equipped with an external manifold. The requirements for the cooling device increase.

[0110] In this case, embodiments of the internal combustion engine may further comprise in which the liquid-type cooling device has a cooling circuit which comprises at least one cooler of the exhaust gas recirculation device.

[0111] If at least one EGR cooler is integrated into the cooling circuit of the engine cooling device, the plurality of components and assemblies required to form the circuit can be provided only separately, since these components and assemblies can be used for the cooling circuit of the EGR cooler and also for the cooling circuit of the engine cooling device, which results in synergy effects and cost savings, but also requires weight reduction.

[0112] For example, it is desirable to provide only one pump for delivering the coolant and one container for storing the coolant.The heat dissipated to the coolant from the internal combustion engine and the EGR cooling device can be extracted from the coolant in a common heat exchanger.

[0113] The exhaust gas energy or exhaust gas heat absorbed by the coolant in the EGR cooling device can therefore also be utilized more easily, for example for warming the internal combustion engine or the engine oil.

[0114] Figure 1 A first exemplary embodiment of an internal combustion engine 1 with an exhaust gas recirculation device 4 is shown schematically.

[0115] The internal combustion engine 1 may comprise an intake system 3 for supplying charge air to the cylinders and have an exhaust gas discharge system 2 for discharging exhaust gas from the cylinders.

[0116] For mechanical supercharging, the internal combustion engine 1 may be equipped with an exhaust-gas turbocharger 6 which comprises a turbine 6 b arranged in the exhaust-gas discharge system 2 and a compressor 6 a arranged in the intake system 3 .

[0117] Furthermore, an exhaust gas recirculation device 4 is provided, which has a recirculation line 4a, which branches off from the exhaust gas discharge system 2 downstream of the turbine 6b so as to form a first junction 2a, and leads to the intake system 3 upstream of the compressor 6a so as to form a second junction 3a. A first control element 7 is arranged at the second junction 3a. A combination valve 7a can be used as the first control element 7, which is used for regulating the amount of recirculated exhaust gas (i.e., the recirculation rate) and therefore also for deactivating the exhaust gas recirculation device 4.

[0118] The cooler 5 is arranged in the first recirculation line 4a. The cooler 5 has a coolant conduction cooling jacket for transferring heat between the exhaust gas and the coolant, and is or can be fluidly connected to the engine cooling system 12. Using the coolant, the exhaust gas can be cooled and the exhaust gas energy can be recovered or used.

[0119] The first cooler 5 is equipped with a phase change material 5a. The phase change material 5a exists in a liquid phase or a solid phase according to the instantaneous material temperature; when the material temperature rises, it stores exhaust heat, and as the material temperature decreases, it releases the stored heat again to the exhaust gas flowing through the cooler 5.

[0120] In this case, in one operating mode, the phase change material 5a can extract heat from the hot exhaust gas during cooling and serve as an energy storage device; in another operating mode, it can return the stored energy to the exhaust gas during heating. The cooler 5 equipped with the phase change material 5a can extract more energy from the exhaust gas than a conventional cooler, and can also introduce additional heat into the exhaust gas when needed.

[0121] A further exhaust gas conducting line 11 is provided which branches off from the first recirculation line 4 a downstream of the first cooler 5 in order to form a third junction point 10 and opens into the exhaust gas discharge system 2 in order to form a fourth junction point 2 b .

[0122] In the present case, the fourth junction point 2b is arranged in the exhaust gas discharge system 2 downstream of the first junction point 2a. The second control element 8 is arranged at the fourth junction point 2b and is configured as a 3 / 3-way directional control valve 8a (e.g., it has three line connections and three switching positions), and connects the first recirculation line 4a to the exhaust gas discharge system 2 downstream of the first cooler 5 via the further exhaust gas conducting line 11 and the fourth junction point 2b, or separates the further exhaust gas conducting line 11 from the exhaust gas discharge system 2.

[0123] In individual cases, the second control element 8 can be used as a throttle element for regulating (eg increasing) the exhaust gas pressure upstream of the exhaust gas discharge system 2 , whereby the charge pressure gradient across the first cooler 5 is also increased.

[0124] Thus, the first cooler 5 can be used to cool the exhaust gas for recirculation, but can also be used for energy recovery when the exhaust gas recirculation device 4 has been deactivated. Figure 1 In one example of a first operating mode shown in FIG. 2 , both control elements 7 , 8 are set so that the exhaust gas to be recirculated is cooled and energy is recovered from the exhaust gas extracted from the exhaust gas discharge system 2 at the first junction 2 a and reintroduced into the exhaust gas discharge system 2 at the fourth junction 2 b. Figure 2 , Figure 3 and Figure 4 Other operating modes are discussed in more detail.

[0125] exist Figure 1 In some examples, the second cooler can be arranged downstream of the first cooler 5. The second cooler can be different from the first cooler, and the second cooler can be dedicated to cooling only the exhaust gas. In this way, the second cooler can have no PCM. Additionally or alternatively, the second cooler can be exactly the same as the first cooler 5.

[0126] Downstream may refer to a component being arranged relative to another component so that the downstream component may receive gas after the upstream component. Thus, if a second cooler is arranged downstream of a first cooler, the first cooler may receive exhaust gas before the second cooler.

[0127] In some embodiments, additionally or alternatively, there may be a third control element disposed between the first cooler 5 and the exhaust gas discharge system 2. The third control element may regulate the flow of exhaust gas from the exhaust gas discharge system 2 to the first cooler 5. In this way, during engine operating conditions where EGR or energy recovery is desired, the third control element may be moved to a fully closed position to block exhaust gas flow to the first cooler 5 and the remainder of the passage downstream thereof.

[0128] Now turn to Figure 2 , which schematically shows a first embodiment of an internal combustion engine 1 and an exhaust gas recirculation device 4 in another example of a first operating mode. Figure 1 For additional features, please refer to Figure 1 The same reference numerals are used for the same parts and components.

[0129] In the first operating mode, the second control element 8 separates the further exhaust gas conducting line 11 from the exhaust gas discharge system 2 and thus separates the first recirculation line 4a and the first cooler 5 from the exhaust gas discharge system 2. However, the first recirculation line 4a is connected to the intake system 3. The first and second control elements 7, 8 are switched or set accordingly. The first cooler 5 cools the exhaust gas exclusively for recirculation, so that the exhaust gas flowing through the first cooler 5 does not return to the exhaust gas discharge system 2.

[0130] In one example, the first operating mode can include one or more operating parameters that allow LP-EGR to flow from the exhaust gas discharge system 2 to the intake system 3. As such, the first control element 7 can be in an at least slightly open position to allow LP-EGR to pass from the first cooler 5 to the intake system 3. In order to ensure that adequate cooling is provided for the LP-EGR, which can reduce emissions and condensate formation, exhaust gas exiting the first cooler 5 may not be returned to the exhaust gas discharge system 2. Therefore, the second control element 8 can be in a fully closed position, thereby fluidly sealing the other exhaust gas conduction line 11 from the exhaust gas discharge system 2. In this way, exhaust gas flowing to the first cooler 5 during the first mode 5 is used as LP-EGR and may not be returned to the exhaust gas discharge system 2. In this way, the first mode 5 can be operated as an LP-EGR cooling mode during engine operating parameters in which the engine cylinders are fueled and not used as a heat recovery mode. Figure 1 and Figure 2 In the example of FIG. 1 , the first operating mode causes at least some exhaust gas to flow into the intake system 3 as EGR, although Figure 1 The example of the first operating mode in FIG. 1 allows some of the exhaust gas leaving the first cooler 5 to return to the exhaust gas discharge system 2, but Figure 2 This is not the case with the first operating mode shown.

[0131] Now turn to Figure 3 , which schematically shows an internal combustion engine 1 in a second operating mode and a first embodiment of an exhaust gas recirculation device 4. Figure 1 and Figure 2 For additional features, please refer to Figure 1 and Figure 2 The same reference numerals are used for the same parts and components.

[0132] In the second operating mode, the first control element 7 separates the first recirculation line 4a from the intake system 3. The second control element 8 connects the further exhaust gas conducting line 11 - and therefore the first recirculation line 4a and the first cooler 5 - to the exhaust gas discharge system 2. The first cooler 5 does not cool any exhaust gas for recirculation, but only the exhaust gas which is taken from the exhaust gas discharge system 2 at the first junction 2a and reintroduced into the exhaust gas discharge system 2 at the fourth junction 2b. The first cooler 5 is therefore used exclusively for energy recovery. The first and second control elements 7, 8 are switched or set accordingly.

[0133] In one example, the second operating mode can include one or more operating parameters that prevent exhaust gas from flowing to the first cooler 5 to flow to the intake system 3. In one example, the second operating mode can be referred to as an energy recovery mode. In response to not expecting LP-EGR in combination with the first cooler 5 being able to capture more heat from the exhaust, the second operating mode can be selected. In one example, if a portion of the phase change material (PCM) in the first cooler is still solid, the first cooler 5 is able to capture and / or store more heat. In this way, the PCM in the first cooler can capture heat from the exhaust, where the PCM can phase change to a liquid. The now cooled exhaust can flow back to the exhaust gas discharge system 2 via a second control element that is in an at least partially open position. Because the first control element 7 is commanded to close in response to the absence of EGR demand, the exhaust leaving the first cooler 5 may not flow to the intake system 3.

[0134] Now turn to Figure 4 , which schematically shows an internal combustion engine 1 in a third operating mode and a first embodiment of an exhaust gas recirculation device 4. Figure 2 Therefore, additional reference is made to Figure 2 The same reference numerals are used for the same parts and components.

[0135] In the third operating mode, the first and second control elements 7, 8 are as follows Figure 2 The internal combustion engine 1 is deactivated, which may include cylinders of the engine which are no longer fuelled.

[0136] The energy stored in the phase change material 5 a of the cooler 5 is in this case introduced into the exhaust gas which is taken from the exhaust gas discharge system 2 via the recirculation line 4 a and introduced into the intake system 3 in order to heat the exhaust gas and prevent or delay cooling of the inactive internal combustion engine 1 .

[0137] The exhaust gas taken from the exhaust gas discharge system 2 is additionally heated while flowing through the cooler 5 and is supplied to the cylinders of the inactive internal combustion engine 1 via the intake system 3 so that the operating temperature of the internal combustion engine 1 does not drop or drops slowly.

[0138] In other words, the third operating mode can be substantially similar to the first operating mode, except that the engine is not fueled. In this way, in response to the engine temperature falling below a desired threshold rather than in response to the need for EGR, the first control element 7 can be commanded to open. In this way, the first cooler 5 acts as a heating device, wherein the exhaust gas from the exhaust gas discharge system 2 enters the first cooler 5 and is heated by the PCM 5a. In one example, the exhaust gas during the third operating mode can be substantially intake air because the fuel is not burned. The exhaust gas entering the first cooler can be redirected back to the exhaust gas discharge system 2 without flowing through the internal combustion engine 1. In this way, since the second control element is in the closed position, the other exhaust conduction line 11 can be sealed from the exhaust gas discharge system 8.

[0139] Now turn to Figure 5 , which shows a high-level flow chart of a method 500 for determining which of the first, second, and third operating modes to enter. Instructions for executing method 500 and the remaining methods included herein may be executed by a controller based on instructions stored on a memory of the controller and in conjunction with signals received from sensors of the engine system, such as those described below with reference to Figure 7 According to the methods described below, a controller may employ engine actuators of an engine system to adjust engine operation.

[0140] Method 500 begins at 502, which may include determining, estimating, and / or measuring current engine operating parameters. Current engine operating parameters may include, but are not limited to, one or more of boost pressure, pedal position, engine temperature, engine speed, EGR flow rate, mass air flow, throttle position, and air / fuel ratio.

[0141] Method 500 may proceed to 504, which may include determining whether EGR is desired. EGR may be desired during more open throttle positions where more oxygen and nitrogen are flowing to the engine. This may otherwise correspond to leaner conditions (where the air / fuel ratio is greater than 1) such that there is excess air. In this way, EGR may dilute the charge, thereby producing less nitrogen oxides.

[0142] If EGR is desired, method 500 may proceed to 506, which may include entering a first operating mode, as described below with reference to Fig. 6A If EGR is not desired, method 500 may proceed to 508, which may include determining whether the engine is deactivated. If the engine is not fueled, the engine may be deactivated. That is, when the engine is deactivated, the injectors in the engine no longer inject fuel or some other fuel source into the engine.

[0143] If the engine is not deactivated (eg, combustion), method 500 may proceed to 510 , which may include entering a second operating mode, as described below with reference to Figure 6B If the engine is disabled (eg, not burning), method 500 may proceed to 512, which may include entering a third operating mode, as described below with reference to Figure 6C described.

[0144] Now turn to Fig. 6A , which shows a method 600 for operating an engine in a first operating mode. The method 600 begins at 602, which includes closing a second control element. As described above, the second control element (e.g., Figure 1-Figure 4 A second control element 8) is arranged in the other exhaust gas conduction line and can adjust the amount of exhaust gas directed back to the exhaust system from the first cooler. By closing the second control element, the exhaust gas flow leaving the first cooler can not flow through the other exhaust gas conduction line and return to the exhaust system. In this way, the exhaust gas in the first cooler is used as EGR in the first operating mode.

[0145] Method 600 may proceed to 604, which may include opening a first control element. By opening the first control element, a recirculation line (e.g., Figure 1-Figure 4 Exhaust gas in the recirculation line 4a) can flow through the first control element and enter the intake system. In one example, the opening of the first control element can be based on the required EGR amount, wherein when more EGR is required, the first control element is moved to a more open position. In this way, the first control element can be actuated from a fully closed position (e.g., 0% EGR flow) to a fully open position (e.g., 100% EGR flow) and any position therebetween.

[0146] Method 600 may proceed to 606 , which may include flowing a portion of exhaust gas from the exhaust system through the first cooler, through the recirculation line, and into the intake system. This may further include preventing exhaust gas from flowing from the recirculation line through another exhaust gas conducting line and back to the exhaust system.

[0147] Method 600 may proceed to 608, which may include continuing to operate in the first mode until EGR is no longer desired. In response to EGR no longer being required, the first control element may be closed and the second control element may be opened. Thus, in some examples, the second operating mode may be entered.

[0148] Now turn to Figure 6B , which shows a method 610 for operating the engine in a second operating mode. In some examples, the second operating mode can be a default mode, where the second operating mode includes flowing exhaust gas from the exhaust system to the first cooler, and then flowing exhaust gas from the first cooler back to the exhaust system for discharge to the ambient atmosphere.

[0149] Method 610 begins at 612, which includes closing a first control element. By closing the first control element, exhaust gas may be prevented from flowing through the recirculation line to the intake system. Therefore, EGR flow may be prevented.

[0150] Method 610 may proceed to 614, which may include opening the second control element. Thus, exhaust gas from the exhaust system may flow to the first cooler, wherein the exhaust gas in the first cooler may be directed through another exhaust conduction line and returned to the exhaust system. Thus, the second operating mode may be an energy recovery mode.

[0151] Method 610 may proceed to 616 which may include flowing a portion of exhaust gas from the exhaust system through the first cooler, through the opened second control element, and back to the exhaust system. The first control element may be closed to prevent EGR flow.

[0152] Method 610 may proceed to 618, which may include continuing the second operating mode until EGR is requested or until the engine is deactivated. In some examples, the second operating mode may be terminated in response to the first cooler no longer being able to recover heat from the exhaust. That is, the second operating mode may be terminated in response to the PCM of the first cooler being completely turned into a heating stage (e.g., liquid) such that it is no longer heated by the exhaust. In response, in addition to the first control element being closed, the second control element may also be closed so that the exhaust remains in the exhaust system.

[0153] In some examples, additionally or alternatively, there may be a third control element disposed between the exhaust system and the first cooler, wherein the third control element may regulate exhaust gas flow from the exhaust system to the first cooler. In such an example, in response to the PCM no longer being able to be heated by the exhaust gas, the third control element may move to a closed position.

[0154] Now turn to Figure 6C , which shows a method 620 for operating the engine in a third operating mode. In some examples, such as the example of method 620, the third operating mode can be performed after deactivating the engine. In this way, by heating the gases in the exhaust system via the PCM in the first cooler, the engine temperature can be maintained at a desired temperature, as described below.

[0155] Method 620 may begin at 622, which may include closing a second control element, similar to Fig. 6A 602 of method 600. In this way, the exhaust gas from the first cooler may not flow through another exhaust gas conducting line and return to the exhaust system.

[0156] Method 620 may proceed to 624, which may include opening the first control element. Unlike 604 of method 600, which is opened based on EGR demand, the first control element may be moved to a fully open position. By fully opening the first control element, all exhaust gas in the first cooler may flow to the intake system to heat engine components and exhaust aftertreatment devices downstream of the engine. In addition, fully opening the first control element may allow all heat transferred from the first cooler to the exhaust to be utilized.

[0157] In some examples, additionally or alternatively, the first control element may be metered open such that it is partially open and may be gradually opened if desired. By partially opening the first control element, a controlled amount of heated exhaust gas may flow from the recirculation line to maintain the temperature of the engine. By doing so, the engine may not exceed an upper threshold temperature during its deactivation period.

[0158] Method 620 may proceed to 626, which may include flowing exhaust gas from the exhaust system to a first cooler, heating the exhaust gas in the first cooler, flowing the exhaust gas through a recirculation line and through an at least partially open first control element to an intake system. In this manner, the exhaust gas may be heated by heat recovered from the exhaust gas via the PCM material in the first cooler during engine combustion. By doing so, engine lubricants, coolants, and components may be maintained at desired engine operating temperatures such that the likelihood of degradation may be reduced and friction losses may be reduced.

[0159] Method 620 may proceed to 628, which may include determining whether the engine is still deactivated. If the engine is still not receiving fuel, the engine may still be deactivated. If the engine is still deactivated, method 620 may continue to heat the exhaust gas via the first cooler and flow the heated exhaust gas to the deactivated engine. If the engine is no longer deactivated and is now receiving fuel and combustion, method 600 may proceed to 630, which may include exiting the third operating mode. In some examples, the third operating mode may be terminated, and the second operating mode may then be initiated.

[0160] In some examples, the method may further include adjusting the operation of the first and second control elements in response to a prediction and / or estimate of an upcoming engine deactivation. Engine deactivation may be entered if vehicle speed is decreasing and / or if one or more of the accelerator pedals are released. Additionally or alternatively, engine deactivation may be predicted based on feedback from a navigation system or other GPS device, wherein the prediction may be based on the route driven. Coasting may occur along portions of the route that are far ahead of traffic lights, downhill, and along highways. If deactivation is predicted, the method may include initiating a second operating mode to recover heat from the exhaust gas to the first cooler while not flowing EGR. This may allow the engine to remain hot and not be cooled by EGR while recovering more heat from the exhaust gas in preparation for engine deactivation. By doing so, engine deactivation may be extended while maintaining engine temperature, thereby reducing emissions and improving fuel economy.

[0161] In some examples, additionally or alternatively, the method may further include adjusting the operation of the first and second control elements during engine deactivation. The adjustment may occur in response to the engine temperature. For example, if the engine temperature is within the desired engine temperature range at the beginning of engine deactivation, the third operating mode may be delayed and the second operating mode may be maintained. Additionally or alternatively, if the third control element is arranged between the first cooler and the exhaust system, the third control element may be closed to prevent exhaust gas from flowing to the first cooler and the intake system. In response to the engine temperature dropping below the desired engine temperature range, the third operating mode may be executed, wherein the first control element is opened and the second control element is closed and the third control element (if present) is opened. In this way, the exhaust gas flow to the first cooler during deactivation may be adjusted in response to the engine temperature.

[0162] If the engine temperature increases back to a temperature within the desired engine temperature range and / or if the heat of the first cooler is dissipated, the third operating method may be disabled and exhaust gas flow to the engine may be prevented.

[0163] Now turn to Figure 7 , which depicts an engine system 100 for a vehicle. The vehicle may be a road vehicle having drive wheels in contact with a road surface. The engine system 100 includes an engine 710 that includes a plurality of cylinders. Figure 7 One such cylinder or combustion chamber is shown in detail. The various components of engine 710 may be controlled by electronic engine controller 712. Engine 710 may be similar to Figure 1-Figure 4 An internal combustion engine 1 is used.

[0164] The engine 710 includes a cylinder block 14 including at least one cylinder bore 20 and a cylinder head 16 including an intake valve 152 and an exhaust valve 154. In other examples, in which the engine 710 is configured as a two-stroke engine, the cylinder head 16 may include one or more intake ports and / or exhaust ports. The cylinder block 14 includes a cylinder wall 32, in which a piston 36 is located and connected to a crankshaft 40. Thus, when coupled together, the cylinder head 16 and the cylinder block 14 may form one or more combustion chambers. In this way, the volume of the combustion chamber 30 is adjusted based on the oscillation of the piston 36. The combustion chamber 30 may also be referred to herein as a cylinder 30. The combustion chamber 30 is shown as being in communication with the intake manifold 144 and the exhaust manifold 148 via respective intake valves 152 and exhaust valves 154. Each intake valve and exhaust valve may be operated by an intake cam 51 and an exhaust cam 53. Alternatively, one or more of the intake and exhaust valves may be operated by an electromechanically controlled valve coil and armature assembly. The position of intake cam 51 may be determined by intake cam sensor 55. The position of exhaust cam 53 may be determined by exhaust cam sensor 57. Thus, when valves 152 and 154 are closed, combustion chamber 30 and cylinder bore 20 may be fluidly sealed such that gas cannot enter or leave combustion chamber 30.

[0165] Combustion chamber 30 may be formed by cylinder wall 32, piston 36, and cylinder head 16 of cylinder block 14. Cylinder block 14 may include cylinder wall 32, piston 36, crankshaft 40, etc. Cylinder head 16 may include one or more fuel injectors (such as fuel injector 66), one or more intake valves 152, and one or more exhaust valves (such as exhaust valve 154). Cylinder head 16 may be coupled to cylinder block 14 by fasteners (such as bolts and / or screws). In particular, when coupled, cylinder block 14 and cylinder head 16 may be in sealing contact with each other by gaskets, and thus cylinder block 14 and cylinder head 16 may seal combustion chamber 30, so that when intake valve 152 is open, gas can only flow into and / or out of combustion chamber 30 via intake manifold 144, and when exhaust valve 154 is open, gas can only flow into and / or out of combustion chamber 30 via exhaust manifold 148. In some examples, each combustion chamber 30 may include only one intake valve and one exhaust valve. However, in other examples, more than one intake valve and / or more than one exhaust valve may be included in each combustion chamber 30 of engine 710 .

[0166] In some examples, each cylinder of engine 710 may include a spark plug 192 for initiating combustion. In selected operating modes, ignition system 190 can provide an ignition spark to cylinder 14 via spark plug 192 in response to spark advance signal SA from controller 712. However, in some embodiments, spark plug 192 may be omitted, for example, engine 710 may initiate combustion by auto-ignition or by injecting fuel, as in the case of some diesel engines.

[0167] Fuel injector 66 may be positioned to inject fuel directly into combustion chamber 30, which is known to those skilled in the art as direct injection. Fuel injector 66 delivers liquid fuel in proportion to the pulse width of signal FPW from controller 712. Fuel is delivered to fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. Driver 68 supplies operating current to fuel injector 66 in response to controller 712. In some examples, engine 710 may be a gasoline engine, and the fuel tank may include gasoline, which may be injected into combustion chamber 30 by injector 66. However, in other examples, engine 710 may be a diesel engine, and the fuel tank may include diesel fuel, which may be injected into the combustion chamber by injector 66. In addition, in such an example where engine 710 is configured as a diesel engine, engine 710 may include a glow plug to initiate combustion in combustion chamber 30.

[0168] Intake manifold 144 is shown communicating with throttle 62, which adjusts a position of throttle plate 64 to control air flow to engine cylinders 30. This may include controlling air flow of boost air from intake boost chamber 146. In some embodiments, throttle 62 may be omitted and air flow to the engine may be controlled by a single intake system throttle (AIS throttle) 82 coupled to intake passage 42 and located upstream of intake boost chamber 146. In another example, AIS throttle 82 may be omitted and air flow to the engine may be controlled with throttle 62.

[0169] In some embodiments, engine 710 is configured to provide exhaust gas recirculation or EGR. When included, EGR may be provided as high pressure EGR and / or low pressure EGR. In examples where engine 710 includes low pressure EGR, low pressure EGR may be provided to the engine intake system at a location downstream of air intake system (AIS) throttle 82 and upstream of compressor 162 via EGR passage 135 and EGR valve 138 from a location in the exhaust system downstream of turbine 164. EGR may be drawn from the exhaust system into the intake system when a pressure differential exists to drive flow. The pressure differential can be created by partially closing AIS throttle 82. Throttle plate 84 controls the pressure at the inlet of compressor 162. The AIS may be electronically controlled and its position may be adjusted based on an optional position sensor 88. In one example, EGR passage 135 may be substantially similar to Figure 1-Figure 4 Thus, the EGR valve 138 may represent a third control element disposed upstream of the first cooler 5, between the exhaust passage and the first cooler 5. In this way, the EGR valve 138 may be shaped to regulate the exhaust gas flow to the first cooler.

[0170] Ambient air is drawn into combustion chamber 30 via intake passage 42, which includes air filter 156. Thus, air first passes through air filter 156 and enters intake passage 42. Compressor 162 then draws air from intake passage 42 to pass through compressor outlet pipe ( Figure 7 164). In some examples, intake passage 42 may include an air box (not shown) having a filter. In one example, compressor 162 may be a turbocharger, wherein the power of compressor 162 is extracted from the exhaust flow through turbine 164. Specifically, the exhaust gas may rotate turbine 164, which is coupled to compressor 162 via shaft 161. Wastegate 72 allows exhaust gas to bypass turbine 164, thereby enabling control of boost pressure under varying operating conditions. Wastegate 72 may be closed (or the opening of the wastegate may be reduced) in response to an increased boost demand (such as during an operator's accelerator pedal press). By closing the wastegate, the exhaust pressure upstream of the turbine can be increased, thereby increasing turbine speed and peak power output. This allows the boost pressure to be increased. In addition, when the compressor recirculation valve is partially open, the wastegate can move toward a closed position to maintain the desired boost pressure. In another example, wastegate 72 may be opened (or the opening of the wastegate may be increased) in response to a reduced boost demand (e.g., during an operator tip-out). By opening the wastegate, exhaust pressure can be reduced, thereby reducing turbine speed and turbine power. This allows for a reduction in boost pressure.

[0171] However, in alternative embodiments, compressor 162 may be a supercharger, wherein power for compressor 162 is extracted from crankshaft 40. Thus, compressor 162 may be coupled to crankshaft 40 via a mechanical linkage, such as a belt. In this way, a portion of the rotational energy output by crankshaft 40 may be transferred to compressor 162 to provide power for compressor 162.

[0172] A compressor recirculation valve 158 (CRV) may be disposed in a compressor recirculation path 159 about compressor 162 so that air may be moved from the compressor outlet to the compressor inlet in order to reduce pressure that may be generated across compressor 162. A charge air cooler 157 may be located in boost chamber 146 downstream of compressor 162 for cooling the boost air charge delivered to the engine intake. Figure 7 In other examples shown, charge air cooler 157 may be positioned downstream of electronic throttle 62 in intake manifold 144. In some examples, charge air cooler 157 may be an air-to-air charge air cooler. However, in other examples, charge air cooler 157 may be a liquid-to-air cooler.

[0173] In the depicted example, the compressor recirculation path 159 is configured to recirculate cooled compressed air from upstream of the charge air cooler 157 to the compressor inlet. In an alternative example, the compressor recirculation path 159 may be configured to recirculate compressed air from downstream of the compressor and downstream of the charge air cooler 157 to the compressor inlet. The CRV 158 may be opened and closed via an electrical signal from the controller 712. The CRV 158 may be configured as a three-state valve having a default half-open position from which the CRV 158 can be moved to a fully open position or a fully closed position.

[0174] Universal Exhaust Gas Oxygen (UEGO) sensor 126 is shown connected to exhaust manifold 148 upstream of emission control device 70. Alternatively, a two-state exhaust gas oxygen sensor may replace UEGO sensor 126. In one example, emission control device 70 may include multiple catalyst bricks. In another example, multiple emission control devices, each having multiple bricks, can be used. Although the depicted example shows UEGO sensor 126 upstream of turbine 164, it will be appreciated that in alternative embodiments, the UEGO sensor may be positioned in the exhaust manifold downstream of turbine 164 and upstream of emission control device 70. Additionally or alternatively, emission control device 70 may include a diesel oxidation catalyst (DOC) and / or a diesel cold start catalyst, a particulate filter, a three-way catalyst, a NO xTraps, selective catalytic reduction devices, and combinations thereof In some examples, a sensor may be positioned upstream or downstream of emission control device 70 , where the sensor may be configured to diagnose a condition of emission control device 70 .

[0175] The controller 712 Figure 7 1 is shown as a microcomputer including a microprocessor unit (CPU) 102, input / output ports (I / O) 104, read only memory (ROM) 106, random access memory (RAM) 108, keep alive memory (KAM) 110, and a conventional data bus. Controller 12 is shown receiving various signals from sensors coupled to engine 710, including, in addition to those previously discussed, engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling sleeve 114; position sensor 134 coupled to input device 130 for sensing input device pedal position (PP) adjusted by vehicle operator 132; a knock sensor (not shown) for determining ignition of exhaust gases; a measurement of engine manifold pressure (MAP) from pressure sensor 121 coupled to intake manifold 144; a measurement of boost pressure from pressure sensor 122 coupled to boost chamber 146; an engine position sensor from Hall effect sensor 118 sensing position of crankshaft 40; a measurement of air mass entering the engine from sensor 120 (e.g., a hot wire air flow meter); and a measurement of throttle position from sensor 58. Barometric pressure may also be sensed (sensor not shown) for processing by controller 712. In a preferred aspect of the present description, the Hall Effect sensor 118 generates a predetermined number of equally spaced pulses per crankshaft revolution, from which the engine speed (RPM) can be determined. The input device 130 may include an accelerator pedal and / or a brake pedal. Thus, the output from the position sensor 134 may be used to determine the position of the accelerator pedal and / or the brake pedal of the input device 130, and thus determine the desired engine torque. Therefore, the desired engine torque requested by the vehicle operator 132 may be estimated based on the pedal position of the input device 130.

[0176] In some examples, the vehicle 705 can be a hybrid vehicle with multiple torque sources that can be used for one or more wheels 59. In other examples, the vehicle 705 is a conventional vehicle with only an engine, or an electric vehicle with only (one or more) electric machines. In the example shown, the vehicle 705 includes an engine 710 and an electric machine 52. The electric machine 52 can be a motor or a motor / generator (M / G). When one or more clutches 56 are engaged, the crankshaft 40 of the engine 710 and the electric machine 52 are connected to the wheels 59 via the transmission 54. In the depicted example, the first clutch 56 is disposed between the crankshaft 40 and the electric machine 52, and the second clutch 56 is disposed between the electric machine 52 and the transmission 54. The controller 712 can send a signal to the actuator of each clutch 56 to engage or disengage the clutch so as to connect or disconnect the crankshaft 40 from the electric machine 52 and the components connected thereto, and / or connect or disconnect the electric machine 52 from the transmission 54 and the components connected thereto. The transmission 54 can be a gearbox, a planetary gear system, or other types of transmissions. The powertrain can be configured in a variety of ways, including parallel, series, or series-parallel hybrid vehicles.

[0177] The electric machine 52 receives power from the traction battery 58 to provide torque to the wheels 59. The electric machine 52 may also operate as a generator to provide power to charge the battery 58, such as during a braking operation.

[0178] Controller 712 from Figure 7 Various sensors receive signals and use Figure 7 Various actuators of the controller are used to adjust the engine operation based on the received signals and the instructions stored in the memory of the controller. For example, adjusting the operation of the first, second and third control elements can be responsive to engine temperature, engine fueling or other conditions.

[0179] Now turn to Figure 8 , which shows the instructions for executing in response to various engine operating conditions Figure 5 , Fig. 6A , Figure 6B and Figure 6C The engine operation sequence 800 of the method of FIG. The engine operation sequence includes a curve 810 showing the engine temperature and a dashed line 812 indicating the lower end of the desired engine operating temperature range, a curve 820 showing the EGR demand, a curve 830 showing the EGR flow rate, a curve 840 showing the first cooler temperature, a curve 850 showing whether the engine is disabled, and a curve 860 showing which of the first, second and third operating modes is being executed. Time increases from the left side of the figure to the right side of the figure.

[0180] Prior to t1, the engine temperature (curve 810) is above the lower end of the desired engine operating temperature range (dashed line 812). EGR is not required (curve 820), and therefore, the EGR flow rate is relatively low (curve 830). Figure 8 In the example of , when EGR is not needed, the EGR flow rate is 0. The engine is not deactivated (curve 850). As a result, the second operating mode is selected (curve 860) and the first control element is closed and the second control element is at least partially opened, thereby allowing at least some exhaust gas to flow from the exhaust system to the first cooler and back to the exhaust system. In this way, the first cooler temperature increases (curve 850).

[0181] At t1, EGR is required and the engine operating mode switches from the second operating mode to the first operating mode. Between t1 and t2, the engine temperature can be maintained above the lower end of the desired engine operating temperature range. The EGR flow rate can begin to increase toward a higher EGR flow rate. In this way, the second control element can be adjusted to a closed position and the first control element can be adjusted to a position that is at least partially open to allow EGR to flow from the recirculation line to the intake system. As the exhaust gas flows through the cooler and enters the intake system, the cooler temperature continues to increase.

[0182] In one example, the first operating mode and the second operating mode can be further distinguished via coolant flow to the first cooler. During the first operating mode, each of the PCM and the coolant can cool the exhaust gas such that coolant does not flow to the first cooler during the first operating mode. However, during the second operating mode, since cooling is not required, coolant flow to the first cooler can be blocked so that the exhaust gas flowing to the cooler can be cooled only by the PCM. In this way, since there is no coolant in the first cooler, the PCM can recover more heat during the second operating mode than the first operating mode. In this way, the temperature increase of the first cooler during the first operating mode can be lower than the temperature increase in the second operating mode.

[0183] At t2, there is no EGR demand and the engine is deactivated. The first operating mode is terminated and the third operating mode is activated. Between t2 and t3, the EGR demand remains non-existent, however, the EGR flow rate remains between a high flow rate and a low flow rate. In one example, the EGR flow rate between t2 and t3 is less than the flow rate between t1 and t2, which can be the result of the first control element moving to a more closed position relative to its position between t1 and t2. This can extend the duration that the engine can receive heated exhaust gas. In addition, the composition of the EGR during the engine deactivation between t2 and t3 can be different from the composition of the EGR during the engine combustion between t1 and t2. In one example, the composition during the engine deactivation may contain fewer carbon-containing compounds. When the EGR is heated by the cooler before flowing to the intake system, the engine temperature can be maintained above the lower end of the desired engine operating temperature range. In this way, during the engine deactivation, the temperature of the cooler can be reduced because heat is transferred from the PCM to the EGR.

[0184] At t3, the engine remains deactivated. The temperature of the cooler is equal to a relatively low temperature and may no longer be able to heat the EGR. In this way, the third operating mode is deactivated and the second operating mode can be activated. Between t3 and t4, since the first cooler no longer includes heat transferred to the exhaust gas, when the EGR flow rate decreases to zero, the deactivation continues and the engine temperature begins to decrease.

[0185] At t4, the engine is no longer deactivated. EGR is not required and, therefore, the second operating mode is maintained. After t4, the engine temperature begins to increase and the second operating mode flows hot exhaust gas to the first cooler, where the cooler temperature begins to increase as heat from the exhaust gas is transferred to the PCM.

[0186] Figure 1-Figure 4 The second embodiment of the internal combustion engine shown in FIG. 9A to 9E A second embodiment may include a first control element which can be used as an EGR valve and, when the exhaust gas recirculation device is active, is used to adjust the recirculation rate, or at least to adjust the recirculated exhaust gas flow rate via the first recirculation line. The use of a combined valve arranged at the second junction allows the recirculated exhaust gas flow rate to be dimensioned and the intake fresh air flow rate to be throttled simultaneously.

[0187] The combined valve can be, for example, a flapper that can be pivoted about an axis extending transversely to the fresh air flow, so that in a first end position the front side of the flapper blocks the intake system and simultaneously opens the recirculation line, and in a second end position the rear side of the flapper covers the recirculation line and simultaneously opens the intake system. An additional valve body connected and thus mechanically connected to the flapper opens or blocks the recirculation line. While the flapper serves to regulate the air flow rate supplied through the intake system, the valve body implements metering of the exhaust gas flow rate that is recirculated.

[0188] The second embodiment of the internal combustion engine may further include the case where the second recirculation line branches off from the exhaust gas discharge system to form a third junction point and opens into the intake system to form a fourth junction point.

[0189] However, in the above context, in particular, embodiments of the internal combustion engine may further comprise wherein the second recirculation line branches off from the exhaust-gas discharge system to form a third junction point and opens into the first recirculation line downstream of the first cooler to form a fourth junction point.

[0190] Then, when the exhaust gas recirculation device is active, the control element arranged at the second junction point can be used to adjust the overall recirculation rate, in particular the exhaust gas flow rate recirculated by the first recirculation line and the exhaust gas flow rate recirculated by the second recirculation line.

[0191] Here, the second embodiment of the internal combustion engine may further include the step of providing a second control element in the second recirculation line downstream of the second cooler.

[0192] The second control element can be a control element which is switchable in two stages and can be used, ie can be used, to connect the second cooler to the first recirculation line or to disconnect the second cooler from the first recirculation line.

[0193] The second control element can therefore also be used to connect the second cooler downstream to the exhaust gas recirculation system and to introduce the exhaust gas into the exhaust gas recirculation system via the second cooler, for which it may be necessary to provide additional exhaust gas conduction lines. The second cooler can then not cool any exhaust gas for recirculation. Instead, the second cooler cools the exhaust gas extracted from the exhaust gas discharge system and introduces this exhaust gas into the exhaust gas discharge system again. That is, in the present case, the second cooler is used only for energy recovery, that is to say for making the energy inherent in the exhaust gas available.

[0194] For the reasons stated above, the second embodiment of the internal combustion engine may further include a further exhaust gas conducting line provided therein which branches from the second recirculation line between the second cooler and the second control element to form a fifth junction point and leads to the exhaust gas discharge system to form a sixth junction point.

[0195] In a second embodiment, the second recirculation line leads to the first recirculation line downstream of the first cooler to form a fourth junction point, and the first cooler can then also be connected downstream to the exhaust gas discharge system via a further exhaust gas conducting line. The first cooler then does not cool any exhaust gas for recirculation, but rather cools the exhaust gas that is reintroduced into the exhaust gas discharge system. Both coolers are then used for energy recovery when the exhaust gas recirculation device has been deactivated.

[0196] In the second embodiment, in which the exhaust gas conduction line branches off from the second recirculation line downstream of the second cooler and opens into the exhaust gas discharge system to form a sixth junction point, it is advantageous for the sixth junction point to be arranged in the exhaust gas discharge system downstream of the first and third junction points.

[0197] In this case, the second embodiment of the internal combustion engine may further include a third control element arranged at the sixth junction. The third control element can preferably be used to close and open another exhaust gas conduction line or to close and open the gas discharge system upstream of the sixth junction. Using the third control element, another exhaust gas conduction line can be connected to the exhaust gas discharge system downstream and upstream of the cooler. The third control element can be used to control the amount of exhaust gas introduced into the exhaust gas discharge system via another exhaust gas conduction line.

[0198] The third control element can also function as a continuously variable throttling element for increasing the exhaust pressure upstream of the exhaust gas discharge system, thereby also driving a driving pressure gradient across the cooler, and a path for the exhaust gas to bypass the cooler is eliminated, or bypass of the cooler is prevented.

[0199] In order to generate the required pressure gradient, a shut-off element can also be arranged upstream of the point at which the exhaust gas recirculation device opens into the intake system, in order to reduce the pressure downstream of the shut-off element on the inlet side.

[0200] Now turn to Fig.9A , which schematically shows a first embodiment of an internal combustion engine 1 in a first operating mode and an exhaust gas recirculation device 4. Thus, the previously described components can be Fig.9A and subsequent figures are numbered similarly.

[0201] The internal combustion engine 1 has an intake system 3 for supplying charge air to the cylinders, and has an exhaust gas discharge system 2 for discharging exhaust gas from the cylinders.

[0202] For mechanical supercharging, the internal combustion engine 1 is equipped with an exhaust-gas turbocharger 6 which comprises a turbine 6 b arranged in the exhaust-gas discharge system 2 and a compressor 6 a arranged in the intake system 3 .

[0203] In addition, an exhaust gas recirculation device 4 having two recirculation lines (i.e., a first recirculation line 4a and a second recirculation line 4b) is provided, wherein a first cooler 905a and a second cooler 905b are arranged in each of the first recirculation line 4a and the second recirculation line 4b, respectively. The first and second coolers 905a, 905b may include a coolant conduction cooling jacket in each case, which is used to transfer heat between the exhaust gas and the coolant. The first and second coolers 905a, 905b may be arranged in parallel and may be used independently of each other to cool the exhaust gas or for energy recovery and are fluidically connected or connectable to an engine cooling device. In some examples, additionally or alternatively, one of the first and second coolers 905a, 905b may be dedicated to cooling only the EGR, while the other cooler may cool the EGR and recover heat from the exhaust gas.

[0204] The first recirculation line 4a branches off from the exhaust gas discharge system 2 downstream of the turbine 6b so as to form a first junction 2a and leads to the intake system 3 upstream of the compressor 6a so as to form a second junction 3A. A first control element 7 is provided at the second junction 3a. A combination valve 7a is used as the first control element 7, which is used to adjust the recirculated exhaust gas flow rate, that is, to adjust the recirculation rate, and therefore also for deactivation of the exhaust gas recirculation device 4.

[0205] The second recirculation line 4 b likewise branches off from the exhaust-gas discharge system 2 downstream of the turbine 6 b and downstream of the first junction 2 a to form a third junction 2 c and opens into the first recirculation line 4 a downstream of the first cooler 905 a to form a fourth junction 10 .

[0206] A further exhaust gas conducting line 11 is provided which branches off from the second recirculation line 4 b downstream of the second cooler 905 b so as to form a fifth junction point 912 and opens into the exhaust gas discharge system 2 so as to form a sixth junction point 2 d .

[0207] In the present case, the sixth junction 2d is arranged in the exhaust gas discharge system 2 downstream of the first and third junctions 2a, 2c. The third control element 902 is arranged at the sixth junction 2d. The third control element 902 may be a continuously variable damper and, in the first operating mode of the second embodiment, is used to close the other exhaust gas conducting line 11. That is, the damper may be moved to a position that blocks the gas in the other exhaust gas conducting line 11 from flowing to the exhaust gas discharge system 2.

[0208] The second control element 8 is arranged in the second recirculation line 4b, downstream of the second cooler 905b and downstream of the fifth junction 912. The second control element 8 can be a 2 / 2-way valve, which can be switched in a two-stage manner, has two line connectors and two switching positions, and connects the two coolers 905a, 905b to the intake system 3 via the second junction 3a or to the exhaust gas discharge system 2 via the sixth junction 2d, or deactivates the second junction cooler 905b, that is, separates the second cooler from the first recirculation line 4a, and connects the second cooler to the exhaust gas discharge system 2 via the sixth junction 2d.

[0209] Thus, both coolers 905a, 905b can be used to cool the exhaust gas for recirculation, but can also be used for energy recovery when the exhaust gas recirculation device has been deactivated. This will be described below based on FIG. 9B to FIG. 9E Discuss in more detail.

[0210] exist Fig.9A In the first operating mode of the second embodiment 900 shown in FIG. 1 , the second control element 8 is in an at least partially open position and the first control element 7 seals the first recirculation line 4 a from the intake system 3. Thus, the exhaust gas recirculation device 4 is deactivated. Due to the blocking of the other exhaust gas conduction line 11 by closing the exhaust gas conduction line 11 via the third control element 902, it is also possible without energy recovery using the EGR coolers 905 a, 905 b. In this way, when the second embodiment 900 is in the first operating mode, the exhaust gas can remain in the exhaust gas discharge system without flowing to the first and second EGR coolers 905 a, 905 b.

[0211] Now turn to Fig. 9B , which schematically shows a second embodiment 900 of an internal combustion engine 1 and an exhaust gas recirculation device 4 in a second operating mode 920. Fig.9A Related additional features, therefore refer also to Fig.9A The same reference numerals are used for the same parts and components.

[0212] In the second operating mode 920, both the first and second coolers 905a, 905b cool the exhaust gas for recirculation. The second recirculation line 4b is connected to the first recirculation line 4a, and the first recirculation line 4a is connected to the intake system 3. The first control element 7 is switched or set to an at least partially open position to allow the exhaust gas from the first recirculation line to flow to the intake system 3. In addition, the second control element 8 is in an at least partially open position, and the further exhaust gas conduction line 11 continues to be closed by the third control element 902, which is maintained in a position to seal the further exhaust gas conduction line 11 from the exhaust gas discharge system 2.

[0213] In particular, if the internal combustion engine has been operated or is operated at a relatively high load and the coolant or the first and second coolers 905a, 905b have been heated, it may be desirable to recirculate the exhaust gas through the coolers 905a, 905b. The heated coolers 905a, 905b and the hot coolant then cool the exhaust gas to a lesser extent. In some cases, the heated coolers 905a, 905b and the hot coolant even introduce heat into the exhaust gas. The high-temperature exhaust gas is recirculated into the cylinder, thereby raising the temperature in the cylinder and reducing friction losses.

[0214] Now go to Fig. 9C , which schematically shows a second embodiment 900 of an internal combustion engine 1 and an exhaust gas recirculation device 4 in a third operating mode 930. Fig.9A and / or Fig. 9B For additional features, please refer to Fig.9A and / or Fig. 9B The same reference numerals have been used for the same parts and components.

[0215] In the third operating mode 930, only the first cooler 905a cools the exhaust gas for recirculation, for which purpose the first recirculation line 4a is connected to the intake system 3 via the second junction 3a. The second recirculation line 4b is separated and / or sealed from the first recirculation line 4a together with the second cooler 905b and is connected to the exhaust gas discharge system 2 via the exhaust gas conduction line 11 and the sixth junction 2d. Therefore, the second cooler 905b is used for energy recovery. The first control element 7 connects the first recirculation line 4a to the intake system 3, and the second control element 8 is in the closed position and separates the second recirculation line 4b from the first recirculation line 4a. The third control element 902 opens the other exhaust gas conduction line 11 in the third operating mode 930.

[0216] In one example, during the third operating mode 930 of the second embodiment 900 of the internal combustion engine 1, the second cooler 905b may not receive a coolant flow. In this way, the phase change material (PCM) arranged in the second cooler 905b may store all heat recovered from the exhaust gas flowing therethrough. In this way, the first cooler 905a may be the only cooler providing a cooling effect on the EGR, while the second cooler 905b provides a cooling effect on the exhaust gas that does not flow into the intake system 1 but flows to the ambient atmosphere.

[0217] Now turn to Fig.9D , which schematically shows a second embodiment 900 of an internal combustion engine 1 and an exhaust gas recirculation device 4 in a fourth operating mode 940. Fig.9A , Fig. 9B and / or Fig. 9C Related additional features, therefore refer also to Fig.9A , Fig. 9B and Fig. 9C The same reference numerals are used for the same parts and components.

[0218] In the fourth operating mode 940, the exhaust gas recirculation device 4 has been deactivated, and the first and second coolers 905a, 905b are used for energy recovery when the exhaust gas recirculation device 4 is deactivated. The first and second control elements 7, 8 are switched or set accordingly, so that the first control element 7 closes and seals the first recirculation line 4a from the intake system, and the second control element 8 at least partially opens and fluidically connects the first recirculation line 4a to the second recirculation line 4b. The two coolers 905a, 905b are connected to the exhaust gas discharge system 2 via the sixth junction 2d and are separated from the intake system 3.

[0219] The first control element 7 separates the first recirculation line 4a from the intake system 3, and the second control element 8 is in an open position and connects the two recirculation lines 4a, 4b. The third control element 902 opens the other exhaust gas conduction line 11 in the fourth operating mode 940. In this way, the PCM in each of the first and second coolers 905a, 905b can recover energy from the exhaust gas. This can occur in response to one or more of undesired EGR, an upcoming engine fuel cut event, and the first and second coolers 905a, 905b being able to recover more exhaust heat.

[0220] Now turn to Fig.9E , which schematically shows a second embodiment 900 of an internal combustion engine 1 and an exhaust gas recirculation device 4 in a fifth operating mode 950. Fig. 9C Related additional features, therefore refer also to Fig. 9C The same reference numerals are used for the same parts and components.

[0221] The first cooler 905 a cools the exhaust gas for recirculation in the fifth operating mode 950 . For this purpose, the first control element 7 connects the first recirculation line 4 a to the intake system 3 .

[0222] The second recirculation line 4b is separated from the first recirculation line 4a together with the second cooler 905b and connected to the exhaust gas discharge system 2 via the exhaust gas conduction line 11 and the sixth junction 2d. Therefore, the second cooler 905b is used for energy recovery. For this purpose, the second control element 8 is in the closed position and separates the second recirculation line 4b from the first recirculation line 4a.

[0223] In the fifth operating mode 950, the third control element 902 opens the other exhaust gas conduction line 11 and the exhaust gas discharge system 2 upstream of the sixth junction point 2d. The latter measure allows high exhaust gas flow rates, which can occur at high loads or high engine speeds, and the pivotable baffle acts as a pressure relief valve at this high exhaust gas flow rate and opens the exhaust gas discharge system 2 to avoid excessive exhaust gas backpressure. This pressure relief function can also be triggered in other operating modes and is implemented in a passive self-control manner by a spring in the second embodiment shown in the figure. Therefore, when EGR is desired and when the exhaust gas flow rate is above a threshold flow rate, the fifth operating mode 950 can be used as an energy recovery mode, so that if the third control element 902 diverts all exhaust gas to the first and second coolers 905a, 905b, then the exhaust backpressure will exceed the threshold pressure and the engine operation can become less efficient. In this way, in order to release the backpressure while still recovering exhaust heat, the third control element 902 is moved to Fig.9A and Fig. 9C A position intermediate between the positions shown in .

[0224] In one example, a second embodiment of an internal combustion engine includes a system comprising a first cooler arranged along a first recirculation line and a second cooler arranged along a second recirculation line. A first control element regulates the exhaust flow from the first recirculation line to the intake system. A second control element regulates the exhaust flow from the first recirculation line to the second recirculation line. A third control element includes a pivotable baffle element that is configured to regulate the exhaust flow from the second recirculation line to the exhaust system. Each of the first and second coolers can be configured to cool and recover heat from the exhaust gas flowing therethrough. Additionally or alternatively, one of the coolers can be configured to recover heat and the other can be configured to cool only the EGR, such that one cooler can receive a coolant and the other can include a phase change material.

[0225] In this way, the EGR cooler can be equipped with a phase change material that is shaped to receive and transfer heat to the exhaust gas during one or more engine operating conditions. A series of valves can be used to adjust the engine operating mode to adjust the EGR and the heat transfer to the EGR cooler. The technical effect of equipping the EGR cooler with a phase change material is to maintain engine temperature during non-combustion engine events. By doing so, emissions can be reduced.

[0226] An embodiment of an internal combustion engine having at least one cylinder, an intake system for supplying air to the at least one cylinder, an exhaust gas discharge system for discharging exhaust gas, and an exhaust gas recirculation device including at least one recirculation line, wherein at least one cooler and at least one control element are arranged in the at least one recirculation line for setting a predeterminable exhaust gas flow rate for recirculation, and at least one cooler is equipped with a phase change material, wherein the phase change material exists in a liquid phase or a solid phase depending on the material temperature, and stores heat as the material temperature increases and releases the stored heat again when the material temperature decreases. The first example of the internal combustion engine also includes: wherein for the purpose of energy recovery, at least one cooler has at least one coolant conduction cooling jacket for transferring heat between the exhaust gas and the coolant. The second example of the internal combustion engine optionally including the first example also includes: wherein a first recirculation line is provided, a first cooler is arranged in the first recirculation line, and the first recirculation line is connectable to the exhaust gas discharge system at least upstream of the first cooler and to the intake system downstream of the first cooler using at least one control element. A third example of an internal combustion engine optionally including the first and / or second examples further includes: wherein the first recirculation line is at least selectively connected to the intake system and / or the exhaust gas discharge system downstream of the first cooler using at least one control element. A fourth example of an internal combustion engine optionally including one or more of the first to third examples further includes: wherein the first recirculation line branches from the exhaust gas discharge system to form a first junction and leads to the intake system to form a second junction. A fifth example of an internal combustion engine optionally including one or more of the first to fourth examples further includes: wherein the first control element is arranged in the first recirculation line at the second junction. A sixth example of an internal combustion engine optionally including one or more of the first to fifth examples further includes: wherein an exhaust gas conduction line is arranged, the exhaust gas conduction line branches from the first recirculation line downstream of the first cooler to form a third junction and leads to the exhaust gas discharge system to form a fourth junction. A seventh example of an internal combustion engine optionally including one or more of the first to sixth examples further includes: wherein the second control element is arranged at the fourth junction. An eighth example of an internal combustion engine optionally including one or more of the first to seventh examples further includes: wherein the fourth junction is arranged in an exhaust gas discharge system downstream of the first junction. A ninth example of an internal combustion engine optionally including one or more of the first to eighth examples further includes: wherein at least one compressor that can be driven by an auxiliary drive is arranged in an intake system. A tenth example of an internal combustion engine optionally including one or more of the first to ninth examples further includes: wherein at least one exhaust gas turbocharger is provided, the exhaust gas turbocharger including a turbine arranged in the exhaust gas discharge system and a compressor arranged in the intake system.The eleventh example of the internal combustion engine optionally including one or more of the first to tenth examples further includes: wherein at least one recirculation line leads to the intake system downstream of the compressor. The twelfth example of the internal combustion engine optionally including one or more of the first to eleventh examples further includes: wherein at least one recirculation line leads to the intake system upstream of the compressor. The thirteenth example of the internal combustion engine optionally including one or more of the first to twelfth examples further includes: wherein at least one recirculation line branches from the exhaust gas discharge system upstream of the turbine. The fourteenth example of the internal combustion engine optionally including one or more of the first to thirteenth examples further includes: wherein at least one recirculation line branches from the exhaust gas discharge system downstream of the turbine. The fifteenth example of the internal combustion engine optionally including one or more of the first to fourteenth examples further includes: wherein at least one exhaust gas aftertreatment system is provided in the exhaust gas discharge system between the turbine and at least one branched recirculation line. The sixteenth example of the internal combustion engine optionally including one or more of the first to fifteenth examples further includes: wherein a particulate filter is provided as the exhaust gas aftertreatment system for exhaust gas aftertreatment. A seventeenth example of an internal combustion engine optionally including one or more of the first to sixteenth examples further includes: wherein a liquid-type cooling device is provided to form an engine cooling device. An eighteenth example of an internal combustion engine optionally including one or more of the first to seventeenth examples further includes: wherein the liquid-type cooling device has a cooling circuit including at least one cooler of an exhaust gas recirculation device.

[0227] An embodiment of an internal combustion engine, comprising: at least one cylinder, an air intake system for supplying air to the at least one cylinder, an exhaust gas discharge system for discharging exhaust gas, an exhaust gas recirculation device, the exhaust gas recirculation device comprising at least two recirculation lines, wherein in each case a cooler is provided in each recirculation line, and the coolers are arranged in parallel and can be used to cool the exhaust gas independently of one another, the control element being used to set a predeterminable exhaust gas flow rate for recirculation, each cooler being used to cool the exhaust gas for the purpose of energy recovery. The first example of an internal combustion engine also comprises: wherein for the purpose of energy recovery, each cooler has at least one coolant conduction cooling jacket for transferring heat between the exhaust gas and the coolant. A second example of an internal combustion engine optionally including the first example further includes: a first recirculation line is provided, a first cooler is arranged in the first recirculation line, and the first recirculation line is connectable to the exhaust gas discharge system at least upstream of the first cooler and to the intake system downstream of the first cooler using at least one control element, and a second recirculation line provided with a second cooler is provided, the second recirculation line is at least connectable to the exhaust gas discharge system upstream of the second cooler using at least one control element and selectively connectable to the intake system or the exhaust gas discharge system downstream of the second cooler. A third example of an internal combustion engine optionally including the first and / or second examples further includes: wherein the first recirculation line is at least selectively connectable to the intake system or the exhaust gas discharge system downstream of the first cooler using at least one control element. A fourth example of an internal combustion engine optionally including one or more of the first to third examples further includes: wherein the first recirculation line branches from the exhaust gas discharge system to form a first junction and leads to the intake system to form a second junction. A fifth example of an internal combustion engine optionally including one or more of the first to fourth examples further includes: wherein the first control element is arranged in the first recirculation line at the second junction. A sixth example of an internal combustion engine optionally including one or more of the first to fifth examples further includes: wherein the second recirculation line branches from the exhaust gas discharge system to form a third junction and leads to the first recirculation line downstream of the first cooler to form a fourth junction. A seventh example of an internal combustion engine optionally including one or more of the first to sixth examples further includes: wherein the second control element is arranged in the second recirculation line downstream of the second cooler. An eighth example of an internal combustion engine optionally including one or more of the first to seventh examples further includes: wherein an exhaust gas conduction line is arranged, which branches from the second recirculation line between the second cooler and the second control element to form a fifth junction and leads to the exhaust gas discharge system to form a sixth junction. A ninth example of an internal combustion engine optionally including one or more of the first to eighth examples further includes: wherein the sixth junction is arranged in the exhaust gas discharge system downstream of the first and third junctions.A tenth example of the internal combustion engine, optionally including one or more of the first to ninth examples, further includes: wherein the third control element is arranged at a sixth joining point.

[0228] An embodiment of a method, the method comprising flowing exhaust gas heated via an EGR cooler arranged along a recirculation line to an intake system during engine deactivation; and heating the exhaust gas via the EGR cooler. A first example of the method also includes: wherein the EGR cooler includes a phase change material. A second example of the method, optionally including the first example, also includes: wherein the EGR cooler is heated outside of engine deactivation. A third example of the method, optionally including the first and / or second examples, also includes: wherein heating the EGR cooler includes a first operating mode and a second operating mode, wherein the first operating mode includes flowing exhaust gas cooled via the EGR cooler to the intake system, and wherein the second operating mode includes flowing exhaust gas from the exhaust passage to the EGR cooler and back to the exhaust passage without flowing the exhaust gas to the intake system. A fourth example of the method, optionally including one or more of the first to third examples, also includes: wherein the first operating mode also includes flowing coolant to the EGR cooler, and wherein the second operating mode includes the EGR cooler being free of coolant.

[0229] An embodiment of a system includes an engine configured to receive gas from an intake system and configured to discharge gas to an exhaust system, a recirculation line fluidly coupling the exhaust system to the intake system, and a controller, the recirculation line including a cooler containing a phase change material, the controller having computer readable instructions stored on its memory, which, when executed, cause the controller to: initiate a first mode by opening a first valve and closing a second valve to allow exhaust gas to flow from the exhaust system to the intake system when EGR is required during engine combustion; initiate a second mode by closing the first valve and opening the second valve to allow exhaust gas to flow to the cooler and back to the exhaust system when EGR is not required during engine combustion; and initiate a third mode by opening the first valve and closing the second valve to allow exhaust gas to flow from the exhaust system to the intake system when exhaust heating is desired during engine deactivation. The first example of the system also includes: wherein the first mode also includes flowing coolant to the cooler. The second example of the system, which optionally includes the first example, also includes: wherein the second mode also includes not flowing coolant to the cooler. A third example of the system, optionally including the first and / or second examples, further includes: wherein the cooler is a first cooler, and further includes a second cooler arranged downstream of the first cooler or arranged in parallel with the first cooler, and wherein each of the first cooler and the second cooler includes a phase change material. A fourth example of the system, optionally including one or more of the first to third examples, further includes: wherein the third mode also includes the first valve being in a position less open than the position of the first valve in the first mode. A fifth example of the system, optionally including one or more of the first to fourth examples, further includes: wherein engine deactivation includes wherein the engine is not fueled. A sixth example of the system, optionally including one or more of the first to fifth examples, further includes: wherein the third mode also includes the absence of an EGR request. A seventh example of the system, optionally including one or more of the first to sixth examples, further includes: wherein the second mode is an energy recovery mode, and wherein heat from the exhaust is transferred to the phase change material before being redirected to the exhaust system. An eighth example of the system, optionally including one or more of the first to seventh examples, further includes: wherein the third mode includes wherein heating the exhaust also includes cooling the phase change material. A ninth example of the system, optionally including one or more of the first to eighth examples, further includes wherein the exhaust in the third mode includes a different composition than the exhaust in the first mode, and wherein the exhaust in the third mode includes less hydrocarbons than the exhaust in the first mode.

[0230] An embodiment of a method includes: during a first operating mode, flowing exhaust gas having a first temperature to a cooler before flowing the exhaust gas to an intake system; during a second operating mode, flowing the exhaust gas having the first temperature to a cooler before flowing the exhaust gas to the exhaust system; and during a third operating mode, flowing the exhaust gas having a second temperature different from the first temperature to a cooler before flowing the exhaust gas to the intake system, wherein the engine is combusted in the first and second operating modes and wherein the engine is deactivated during the third operating mode, and wherein the cooler includes a phase change material. The first example of the method also includes: wherein the phase change material of the cooler is heated during the first and second operating modes, and the phase change material of the cooler is cooled during the third operating mode. The second example of the method, which optionally includes the first example, also includes: wherein the cooler warms the exhaust gas during the third operating mode, and wherein the exhaust gas in the third operating mode heats or maintains the engine temperature when the engine is deactivated. A third example of the method, optionally including the first and / or second examples, further includes: wherein the cooler is arranged in an EGR passage fluidly coupling the exhaust system to the intake system, further includes a first control element arranged at a junction between the EGR passage and the intake system, wherein the first control element is at least partially opened during the first and third operating modes and closed during the second operating mode, further includes fluidly connecting a portion of the EGR passage downstream of the cooler to another exhaust conduction line of the exhaust system, and wherein the second control element is arranged in the other exhaust conduction line, wherein the second control element is at least partially opened during the second operating mode and closed during the first and third operating modes. A fourth example of the method, optionally including one or more of the first to third examples, further includes: wherein the first operating mode also includes the presence of an EGR request, and wherein the third operating mode includes the absence of an EGR request.

[0231] 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 can be stored as executable instructions in a non-transitory memory and can be performed by a control system including a controller in combination with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Therefore, the various actions, operations, and / or functions shown can be performed in the order shown, in parallel, or omitted in some cases. Similarly, the order of processing is not necessary to achieve the features and advantages of the example embodiments described herein, but the depicted processing order is provided for ease of illustration and description. One or more of the actions, operations, and / or functions shown can be repeatedly performed according to the specific strategy used. Further, the described actions, operations, and / or functions can graphically represent the code in the non-transitory memory of the computer-readable storage medium to be programmed into the engine control system, wherein the described actions are performed by executing instructions in a system including various engine hardware components in conjunction with an electronic controller.

[0232] It should be understood that the configurations and routines disclosed herein are exemplary in nature, and these specific embodiments should not be considered limiting, as many 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 disclosed herein, and other features, functions, and / or properties.

[0233] As used herein, unless otherwise indicated, the term "substantially / about" is interpreted to mean ±5% of the range.

[0234] The appended claims particularly point out certain combinations and subcombinations believed to be 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 combinations of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal to, or different in scope from the original claims, are also deemed to be included in the subject matter of the present disclosure.

Claims

1. A method for an engine, comprising: During engine deactivation, flowing exhaust gas heated via an EGR cooler arranged along a recirculation line to an intake system; and heating the exhaust gas via an EGR cooler; Wherein heating the EGR cooler includes a first operating mode and a second operating mode, wherein the first operating mode includes flowing exhaust gas cooled via the EGR cooler to the intake system, and wherein the second operating mode includes flowing exhaust gas from an exhaust passage to the EGR cooler and back to the exhaust passage without flowing the exhaust gas to the intake system. 2 . The method of claim 1 , wherein the EGR cooler comprises a phase change material. 3 . The method of claim 1 , further comprising heating the EGR cooler outside of deactivation of the engine. 4 . The method of claim 1 , wherein the first operating mode further comprises flowing coolant to the EGR cooler, and wherein the second operating mode comprises the EGR cooler being free of coolant.

5. A system for an engine, comprising: an engine configured to receive gases from an intake system and configured to discharge gases to an exhaust system; fluidly coupling the exhaust system to a recirculation line of the intake system, the recirculation line including a cooler including a phase change material; as well as A controller having computer readable instructions stored on a memory thereof, which, when executed, cause the controller to: When EGR is required during engine combustion, a first mode is initiated by opening a first valve and closing a second valve to allow exhaust gas to flow from the exhaust system to the intake system; When EGR is not required during engine combustion, a second mode is initiated by closing the first valve and opening the second valve to allow exhaust gas to flow to the cooler and back to the exhaust system; as well as When heating by exhaust gas is desired during engine deactivation, a third mode is initiated by opening the first valve and closing the second valve to allow exhaust gas to flow from the exhaust system to the intake system.

6. The system of claim 5, wherein the first mode further comprises flowing coolant to the chiller.

7. The system of claim 5, wherein the second mode further comprises not flowing coolant to the chiller.

8. The system of claim 5, wherein the cooler is a first cooler, and the system further comprises a second cooler arranged downstream of or in parallel with the first cooler, and wherein each of the first cooler and the second cooler comprises the phase change material.

9. The system of claim 5, wherein the third mode further comprises the first valve being in a position that is less open than the position of the first valve in the first mode.

10. The system of claim 5, wherein the engine is deactivated includes wherein the engine is not fueled.

11. The system of claim 5 wherein the third mode further comprises the absence of an EGR request.

12. The system of claim 5, wherein the second mode is an energy recovery mode and wherein heat from the exhaust gas is transferred to the phase change material before being redirected to the exhaust system.

13. The system of claim 5, wherein the third mode includes wherein heating the exhaust gas further comprises cooling the phase change material.

14. The system of claim 5, wherein the exhaust gas in the third mode includes a different composition than the exhaust gas in the first mode, and wherein the exhaust gas in the third mode includes fewer hydrocarbons than the exhaust gas in the first mode.

15. A method for an engine, comprising: During a first operating mode, flowing exhaust gas having a first temperature to a cooler before flowing the exhaust gas to an intake system; during a second operating mode, flowing the exhaust gas having the first temperature to the cooler before flowing the exhaust gas to an exhaust system; as well as During a third operating mode, exhaust gas having a second temperature different from the first temperature is flowed to the cooler before being flowed to the intake system, wherein the engine combusts in the first operating mode and the second operating mode and wherein the engine is deactivated during the third operating mode, and wherein the cooler includes a phase change material.

16. The method according to claim 15, further comprising: The phase change material of the cooler is heated during the first and second operating modes, and the phase change material of the cooler is cooled during the third operating mode.

17. The method of claim 15, wherein the cooler warms the exhaust gas during the third operating mode, and wherein the exhaust gas in the third operating mode heats or maintains engine temperature when the engine is deactivated.

18. The method of claim 15, wherein the cooler is arranged in an EGR passage fluidly coupling the exhaust system to the intake system, the method further comprising a first control element arranged at a junction between the EGR passage and the intake system, wherein the first control element is at least partially opened during the first operating mode and the third operating mode and is closed during the second operating mode, the method further comprising another exhaust gas conduction line fluidly coupling a portion of the EGR passage downstream of the cooler to the exhaust system, and wherein a second control element is arranged in the another exhaust gas conduction line, wherein the second control element is at least partially opened during the second operating mode and is closed during the first operating mode and the third operating mode.

19. The method of claim 18, wherein the first operating mode further comprises the presence of an EGR request, and wherein the third operating mode comprises the absence of the EGR request.

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