DE102014219942A1 - A method of operating a supercharged internal combustion engine and supercharged internal combustion engine - Google Patents

Abstract

The present invention relates to a method for operating a supercharged internal combustion engine (2), preferably a vehicle (1), wherein the internal combustion engine (2) has a cooling circuit (9) and a fresh air system (3) for supplying the internal combustion engine (2) with fresh air. In addition, an intermediate circuit (18) is provided, in which an intermediate medium circulates and in which a first evaporator (15) of the refrigeration circuit (9) and a first intercooler (17) of the fresh air system (3) are integrated, the intermediate circuit (18) being fluidic is separated from the fresh air system (3) and from the refrigerant circuit (9). An increased efficiency of the cooling system (8) results from the fact that the intermediate circuit (18) for the first time after an operating start of the internal combustion engine (2) depending on operating parameters of the internal combustion engine (2) and / or the associated vehicle (1) is cooled. The invention further relates to such an internal combustion engine (2).

Description

The present invention relates to methods for operating a supercharged internal combustion engine, preferably in a vehicle, as well as such an internal combustion engine.

To operate an internal combustion engine, a fuel and air are necessary, which are burned in at least one combustion chamber of the internal combustion engine. To increase the performance or provision of higher loads of the internal combustion engine, it is known to charge the internal combustion engine. Here, a compressor is provided in a fresh air system for supplying air to the internal combustion engine, which may be part of an exhaust gas turbocharger. The compressor compresses the air to be supplied to the internal combustion engine and thus provides the internal combustion engine with charge air. As a result of thermodynamic laws, the charging or compression leads to a warming of the charge air, which in turn leads to a low density of the air.

To increase the density of the air or to increase an air mass flow, it is desirable to cool the charge air before supplying to the internal combustion engine. For this purpose, it is known to provide a charge air cooling circuit in which circulates a coolant and having a charge air cooler for cooling the charge air and a coolant radiator for cooling the coolant. Especially at higher loads or power requirements of the internal combustion engine, for example, in an acceleration phase of an associated vehicle, the highest possible cooling of the charge air leads to a further improvement of the performance of the internal combustion engine and reduced formation of pollutants in the exhaust gases of the internal combustion engine. In order to achieve these improvements, the highest possible cooling of the charge air is required. To realize a further cooling of the charge air, a cooling circuit of a cooling system can be used. In the refrigerant circuit circulates a refrigerant which is driven by a refrigerant circuit compressor and flows through an evaporator for evaporating the refrigerant and a condenser for condensing the refrigerant. To use the cooling capacity of the refrigerant circuit, it is basically possible to couple the evaporator of the refrigerant circuit fluidly with the charge air cooling circuit.

In particular, there is the risk of mixing the refrigerant with the charge air or with the coolant, in particular if the refrigerant circuit or the cooling circuit is damaged. The mixing of the refrigerant with the coolant or the air can lead to malfunction of the internal combustion engine and / or the cooling system. If a flammable or flammable coolant or refrigerant is used in the refrigerant circuit or in the charge-air cooling circuit, there is also the risk of combustion or ignition, which represents a considerable safety disadvantage. In addition, the mixing of the refrigerant with the charge air or the coolant reaction products may arise, which also represent a danger.

In addition, the charge air is continuously cooled by the fluidic coupling of the evaporator of the refrigerant circuit with the charge air cooling circuit, which brings disadvantages in the operation of the internal combustion engine with it.

The present invention therefore deals with the problem of specifying, for a method for operating a supercharged internal combustion engine and for such an internal combustion engine, alternative or at least other embodiments which are distinguished by increased safety and / or improved efficiency.

This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the idea of a supercharged internal combustion engine having an intermediate circuit for cooling charge air, a first cooling of the intermediate circuit and thus a first cooling of the charge air via the intermediate circuit after a start of operation of the internal combustion engine depending on operating parameters of the internal combustion engine and / or of the associated vehicle. This does not necessarily mean that the charge air is cooled via the DC link immediately after the start of operation. In particular, the thereby freely available power or energy can be used elsewhere. As a result, an improved efficiency of the internal combustion engine and / or the associated vehicle is thereby achieved.

According to the idea of the invention, it has a refrigerant circuit in which a refrigerant circulates. The internal combustion engine also has a fresh air system for supplying the internal combustion engine with air. In this case, the refrigerant circuit and the fresh air system are coupled heat-transmitting via the intermediate circuit, wherein an intermediate medium circulates in the intermediate circuit in comparison to the refrigerant circulating in the refrigerant circuit. As a result, the refrigerant circuit and the fresh air system are coupled to each other heat transfer. Furthermore, the fresh air system and the refrigerant circuit are fluidly completely separated. As a result, a mixing of the refrigerant with air, in particular charge air, the fresh air system is prevented or a corresponding hazard at least significantly reduced. Thus, the safety of the cooling system or the internal combustion engine or an associated vehicle is increased. According to the idea of the invention, the refrigeration circuit has a refrigerant circuit compressor for driving the refrigerant and an evaporator for evaporating the refrigerant. For compressing or charging the air to be supplied to the internal combustion engine, a compressor is provided in the fresh air system, wherein the compressed air or charge air compressed by the compressor is cooled by a first charge air cooler in the fresh air system. The heat exchange between the refrigerant circuit and the fresh air system via the first evaporator and the first intercooler. This means that the first evaporator and the first intercooler are integrated in the intermediate circuit, wherein the intermediate circuit is fluidly separated from the refrigerant circuit and the fresh air system. In other words, the heat transfer between the refrigerant circuit and the fresh air system runs over the intermediate circuit or via the intermediate medium. The refrigerant circuit cools the intermediate circuit or the intermediate medium via the first evaporator, while the intermediate circuit or the intermediate medium cools the charge air via the first charge air cooler.

The refrigerant circuit usually has, in addition to the first evaporator and the refrigerant circuit compressor, a condenser disposed downstream of the refrigerant compressor and upstream of the first evaporator. The condenser serves to condense the refrigerant.

Usually, the refrigeration circuit also serves to cool another system. For example, in a vehicle, the refrigeration cycle may serve to cool an interior of the vehicle. The refrigerant circuit may therefore be part of an air conditioning system of the vehicle.

In principle, the first evaporator can be used to cool the other system. This means that the first evaporator can be used for cooling the charge air via the intermediate circuit or via the first charge air cooler and for cooling the other system, in particular in the air conditioning system. It is also conceivable to provide for the cooling of the other system in the refrigerant circuit another evaporator, so a second evaporator. Thus, it is possible to use the first evaporator exclusively for the cooling of the charge air, which allows a more efficient and / or more independent cooling of the charge air.

Preferably, the first evaporator and the second evaporator are arranged in different branches of the refrigeration circuit. Accordingly, the refrigeration cycle has a first branch and a second branch different from the first branch. The branches can branch off from the refrigeration circuit at a common branch point. Preferably, the cooling circuit branches off downstream of the capacitor in the two branches, which then open upstream of the condenser again to the refrigerant circuit. In this case, the first evaporator is arranged in the first branch, while the second evaporator is arranged in the second branch. In an equivalent consideration, the first branch may be referred to more immediately as the second branch. This makes it possible to use the first evaporator in the first branch for cooling the charge air, in particular exclusively for this purpose, while the second evaporator for the other use of the refrigeration circuit, so for example, the operation of the air conditioning is used. Accordingly, the second evaporator may be referred to as a main evaporator, while the first evaporator may be referred to as a secondary evaporator. The same applies to the first branch and the second branch: the first branch may be referred to as a branch branch of the cooling circuit, while the second branch may be referred to as a main branch of the cooling circuit. The provision of the refrigeration circuit with two branches and the arrangement of each one of the evaporator in such an associated branch allows flexible operation of the refrigeration circuit. In addition, the cooling of the charge air via the intermediate circuit and the cooling of the other system are virtually separated, which has further operational advantages.

Advantageously, a division of the flow of the refrigerant between the first branch and the second branch is possible. This is preferably realized with the aid of a refrigeration circuit valve device, which is designed or arranged such that it divides the flow of the refrigerant between the first branch and the second branch of the refrigeration circuit. In this case, the refrigeration circuit valve device is in particular designed such that it allows a flow of the refrigerant exclusively through the second branch. This makes it possible to deliver no cooling capacity of the refrigerant circuit to the intermediate circuit or the first intercooler. Furthermore, it is conceivable to design the refrigeration circuit valve device such that an exclusive flow through the first branch of the refrigeration circuit is possible. This makes it possible in particular to increase the output to the intermediate circuit cooling capacity of the refrigerant circuit.

The refrigerant circuit valve device is advantageously designed such that any division of the flow of the refrigerant between the first branch and the second branch is possible. In this case, the distribution of the flow between the first branch and the second branch is preferably adjustable in steps and / or continuously.

The refrigeration circuit valve device may comprise one or more valves which are connected to any one or more valves Location can be arranged in the cooling circuit. In particular, the refrigeration cycle valve device can have at least one such valve in the first branch, in the second branch or in a branching point of the cooling circuit, at which the first branch and the second branch branch off.

For cooling the charge air, a charge air cooling circuit, in which a coolant circulates, is also advantageously provided. The charge air cooling circuit has a second intercooler for cooling the charge air and a coolant radiator for cooling the coolant. In this case, the second charge air cooler is preferably arranged upstream of the first charge air cooler in the fresh air system. This makes it possible, in particular, to cool the charge air independently and / or additionally from the first charge air cooler. If the cooling circuit does not provide any cooling power for cooling the charge air, it is possible by the charge air cooling circuit to nevertheless achieve cooling of the charge air. The charge air cooling circuit may include an associated compressor for driving the coolant, hereinafter referred to as a refrigerant cycle compressor. Here, the intermediate circuit, the charge air circuit and the refrigerant circuit are each fluidly separated from each other.

The coolant, the refrigerant and the intermediate medium may each be different. In particular, the refrigerant may be a phase change refrigerant. The coolant may be a low-temperature coolant. The intermediate medium may be a water-glycol mixture or have such a mixture. Of course, it is also possible that the coolant, the refrigerant and the intermediate medium are at least partially identical.

In preferred embodiments, the condenser of the refrigeration circuit and the coolant radiator are disposed adjacent. The adjacent arrangement of the condenser and the coolant radiator is advantageously designed such that the condenser and the coolant radiator can be cooled together by an air flow. In particular, in an associated vehicle, it is thus possible to cool the condenser and the coolant radiator by a cooling air flow, which is generated and / or amplified at least partially by the airstream and / or by a fan. In this case, the condenser and the coolant radiator are preferably arranged such that they are cooled in succession by the cooling air flow. This can be achieved for example by a substantially parallel arrangement of the condenser and the coolant radiator. Furthermore, the arrangement is advantageously designed such that the condenser is cooled by the cooling air flow before the coolant radiator.

In certain situations, in particular at certain operating points of the internal combustion engine and / or the associated vehicle, it is desirable not to cool the charge air or as little as possible or to reduce cooling of the charge air through the intermediate circuit and thus by the first intercooler, in particular to prevent. For this purpose, the fresh air system has a bypass bypassing the first intercooler, so that the charge air can be guided past the first intercooler when needed. These situations include, for example, phases with low load or with a base load of the internal combustion engine, in which an excessive cooling of the charge air counteracts the overall efficiency or the pollutant emission of the internal combustion engine.

The fresh air system preferably has a fresh air valve device which controls the flow of the charge air through the bypass bypassing the first charge air cooler and / or through the first charge air cooler. Thus, the intercooler can be completely bypassed if necessary. In these situations, the charge air can be cooled exclusively by the second charge air cooler, which accordingly can be referred to as the main charge air cooler. Conversely, the first charge air cooler can be referred to as a secondary charge air cooler.

Preferred embodiments are those in which the fresh air valve device allows a metering of the flow of the charge air between the bypass and the first charge air cooler. Particularly advantageous is any dosage or distribution possible. Thus, it is possible to let the charge air flowing through the fresh air system flow in any subsets through the bypass. In particular, this also makes it possible to prevent a flow of the charge air through the bypass, so that the charge air flows completely through the first charge air cooler. By a corresponding regulation of the fresh air valve device can thus be varied cooling of the charge air reaching the engine, since the charge air flowing through the bypass is not cooled by the first charge air cooler and is admixed downstream of the first charge air cooler of the optionally cooled by the first charge air cooler charge air.

For circulating the intermediate medium in the intermediate circuit, a conveying device, in particular a DC link compressor, can be provided. Said conveyor can be operated arbitrarily. In particular, it is conceivable to operate the DC link conveyor constant. However, to vary the heat exchange between the first charge air cooler and the first evaporator, the performance of the conveyor can be varied. So can a stronger Circulation of the intermediate medium in the intermediate circuit lead to a stronger heat exchange between the first intercooler and the first evaporator. This also allows the cooling of the charge air to be influenced by the first charge air cooler.

In principle, it is conceivable to drive the respective compressors or conveying device of the cooling system by the internal combustion engine. In particular, it can be provided that the refrigerant circuit compressor is drive-connected to the internal combustion engine. The drive connection between the internal combustion engine and the refrigerant circuit compressor can be designed adjustable and in particular detachable. In this way it is possible, for example, at certain operating phases of the internal combustion engine or the associated vehicle, to interrupt the drive connection between the refrigerant circuit compressor and the internal combustion engine in order to provide the total power of the internal combustion engine otherwise available. Such a phase can be present, for example, if an acceleration of the associated vehicle is to take place or if the load of the internal combustion engine is increased. In this case, the flow of the refrigerant in the refrigerant circuit is reduced by the reduction or interruption of the drive of the refrigerant circuit compressor, in particular interrupted. Accordingly, cooling of the charge air with the aid of the first charge air cooler takes place primarily by the cooling capacity previously stored in the intermediate circuit or intermediate medium. The cooling capacity is therefore given in particular by the heat absorption capacity of the DC link. So here serve the intermediate circuit or the intermediate medium as a cold storage for cooling the charge air by means of the first charge air cooler.

If the internal combustion engine or the associated vehicle is started, then the DC link is cooled for the first time when predetermined operating parameters of the internal combustion engine or of the associated vehicle are reached. The first-time cooling of the intermediate circuit by the refrigerant circuit leads to a heat exchange between the first intercooler and the charge air. In other words, the cooling of the charge air through the first intercooler, which depends on a corresponding cooling of the intermediate circuit through the refrigeration circuit, takes place for the first time when said predetermined operating parameters are present. This means in particular that the charge air is not necessarily cooled immediately after the start of operation of the internal combustion engine or the associated vehicle by the first charge air cooler.

Preferably, the DC link is cooled after a start of operation of the internal combustion engine for the first time by the refrigerant circuit when the internal combustion engine is operated for a predetermined time in an upper load range. The cooling of the charge air leads to an increase in the density of the charge air, which can realize higher air mass flows in combustion chambers of the internal combustion engine. As a result, in particular higher powers or loads of the internal combustion engine can be realized. Accordingly, a cooling of the charge air for said higher loads is needed. On the other hand, the cooling of the charge air requires energy, which in the present case is supplied to the intermediate circuit through the refrigeration circuit, so that the charge air can be cooled by the first charge air cooler. At the start of operation of the internal combustion engine energy is also required to start certain processes or to bring the internal combustion engine and / or the vehicle to operating temperature. By first cooling the intermediate circuit through the refrigeration circuit after reaching said upper load ranges, the available energy of the internal combustion engine or of the vehicle or of the cooling system is thus used elsewhere if no increased loads or performances of the internal combustion engine are required. In addition, it has been shown that excessive cooling of the charge air in the lower load ranges of the internal combustion engine, in which a comparatively low power of the internal combustion engine is required, is counterproductive, since this can result in increased fuel consumption of the internal combustion engine and / or increased pollutant emissions. Accordingly, by the initial cooling of the intermediate circuit after a start of operation, when the internal combustion engine is operated for a predetermined time in an upper load range, these disadvantages are also counteracted.

The upper load range of the internal combustion engine usually corresponds to an upper map range of the vehicle. The upper map range results from a dependent representation of a dependent of a speed of the internal combustion engine effective mean pressure of the internal combustion engine. The upper map area and thus the upper load range of the internal combustion engine depends on the respective configuration of the internal combustion engine and / or the associated vehicle. In particular, the internal combustion engine can be located in the upper map range, if effective mean pressures of about 7 bar or more are present.

The cooling of the charge air has the further advantage that a change between an operation of the internal combustion engine with less power or less load and an operation of the internal combustion engine with higher power or higher load takes place faster. In other words, a change between a base load or middle load of the internal combustion engine to a higher load operation can be realized faster. This so-called transient response of the internal combustion engine can thus be improved by cooling the charge air become. Accordingly, the first cooling of the DC link after a start of operation of the internal combustion engine can also take place when such a transient region is present or is to be expected. This may be the case in particular when a first-time load operation of the internal combustion engine is to be expected. Here is realized by the first cooling of the intermediate circuit through the refrigerant circuit, a corresponding cooling of the charge air through the first charge air cooler, so that the transient response of the internal combustion engine is improved. This means that the DC link is cooled for the first time by the refrigeration circuit after an operating start of the internal combustion engine when a load operation of the internal combustion engine is to be expected.

The estimation of an expected load operation can be done in any way. In particular, the cooling system, the internal combustion engine and the associated vehicle for this purpose may have measuring devices that allow the determination of operating parameters of the internal combustion engine or of the vehicle. Furthermore, a control device can be provided which determines an expected load operation of the internal combustion engine on the basis of these operating parameters.

An example of such an operating parameter is the speed of the internal combustion engine. In this case, there is a first cooling of the DC link through the refrigerant circuit when a gradient of the rotational speed exceeds a predetermined value and is positive. This means that a first cooling of the intermediate circuit takes place when the speed of the internal combustion engine is increased for a predetermined time. Such an increase in the rotational speed is an indication of an expected load operation of the internal combustion engine. If the internal combustion engine serves the drive of the vehicle, then this situation may be present in particular when an accelerator pedal of the vehicle is operated more strongly for said predetermined time. This is an indication of a required acceleration or acceleration gain of the vehicle, which requires a, in particular stronger, cooling of the charge air and in which the cooling of the charge air leads to a better transient response of the internal combustion engine or the vehicle.

The predetermined time can be any length. It may depend, in particular, on the particular internal combustion engine as well as on the respective vehicle. The conditions of the cooling system can also have an influence on the given time. If it is, for example, a sporty vehicle, then the predetermined time can be chosen shorter. Even with intermediate circuits with larger thermal masses, the predetermined time can be selected shorter, in particular because a cooling of the intermediate medium or the thermal mass takes a comparatively long time.

The thermal mass is characterized by the fact that it can absorb heat and give off heat. The cooling capacity is thus determined in particular by the thermal mass of the DC link. Due to the heat absorption of the thermal mass, it is possible to cool the DC bus and / or the charge air. Due to the heat release, it is possible to cool the thermal mass. The thermal mass of the DC link includes all components that absorb or release heat. Thus, in particular, the intermediate medium, the first intercooler, the evaporator and connections between the first intercooler and the first evaporator, such as piping to the thermal mass of the intermediate circuit belong.

An expected load operation of the internal combustion engine can also be present when a load operation of the internal combustion engine is signaled. This can be the case in particular when an associated operating mode is set. Such a setting can be done from the outside. In an associated vehicle, for example, it is conceivable that means for setting different operating modes are provided. If an operating mode is set, which can be expected load operation of the internal combustion engine, for example, if a "sports mode" is selected, there is a first cooling of the intermediate circuit by the refrigeration circuit when such an operating mode is set. The setting of this operating mode can also be done before the start of operation of the internal combustion engine. In this case, the first-time cooling of the DC link can take place immediately after the start of operation of the internal combustion engine. In particular, it is conceivable that the operating mode is permanently set. It is therefore conceivable to cool the DC link for the first time immediately after or at the start of operation of the internal combustion engine.

The cooling of the intermediate circuit through the refrigerant circuit is effected by the first evaporator. Accordingly, the initial cooling of the intermediate circuit can be realized by the refrigerant circuit by a first time flowing through the first evaporator of the refrigerant.

For this purpose, for example, the refrigerant circuit valve device can be used, which interrupts or releases a flow of the refrigerant through the first branch. The release can be stepped or continuous. In other words, for the first time cooling of the intermediate circuit by the refrigerant circuit can be provided that the first evaporator is flowed through by the refrigerant for the first time after the start of operation of the internal combustion engine.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show it,

1 to 5 each a schematic, highly simplified, schematic diagram of a vehicle, in different embodiments.

In 1 is a vehicle 1 shown that an internal combustion engine 2 having. The internal combustion engine 2 serves the drive of the vehicle 1 , where the vehicle 1 for driving also further, not shown here, drive devices may have. To operate the internal combustion engine 2 Air is necessary, that of the internal combustion engine 2 with the help of a fresh air system 3 is supplied. This shows the vehicle 1 an exhaust gas turbocharger 4 on, its compressor 5 in the fresh air system 3 is arranged and that of the internal combustion engine 2 compressed air to be supplied. Thus, the internal combustion engine 2 Charge air supplied. The vehicle 1 also has an exhaust system 6 on that in the internal combustion engine 2 resulting exhaust gas dissipates. In the exhaust system 6 is a turbine 7 the exhaust gas turbocharger 4 arranged the the compressor 5 drives.

By compressing the air, the temperature of the compressed air or the charge air increases. However, this affects an efficiency of the internal combustion engine 2 , in particular in power phases or load phases of the internal combustion engine 2 , negative against.

The vehicle 1 has a cooling system 8th on, that the fresh air plant 3 as well as a cooling circuit 9 includes. In the refrigerant circuit 9 circulates a refrigerant from a refrigerant circuit compressor 10 of the refrigeration circuit 9 is driven. In addition, the cooling circuit points 9 downstream of the refrigerant circuit compressor 10 a capacitor 11 for condensing the refrigerant. Downstream of the capacitor 11 indicates the refrigerant circuit 9 a branch point 12 on, from which a first branch 13 and a second branch 14 of the refrigeration circuit 9 branch. The first branch 13 and the second branch 14 open upstream of the refrigerant compressor 10 and thus upstream of the condenser 11 in a junction 47 to the refrigerant circuit 9 each other. It is in the first branch 13 a first evaporator 15 of the refrigeration circuit 9 arranged while in the second branch 14 a second evaporator 16 of the refrigeration circuit 9 is arranged. Accordingly, the first branch acts 13 as a second evaporator 16 immediate bypass of the refrigerant circuit 9 ,

For cooling the charge air has the fresh air system 3 a first intercooler 17 on, the downstream of the compressor 5 in the fresh air system 3 is arranged. The cooling system 8th also has a DC link 18 on, in which an intermediate medium circulates and the fluidic of the refrigerant circuit 9 and the fresh air system 3 is disconnected. The first evaporator 15 as well as the first intercooler 17 are also heat transfer in the DC link 18 involved. That is, a heat transfer between the first intercooler 17 and the first evaporator 15 takes place by means of the intermediate medium. Consequently, the first intercooler are each fluidly separated 17 flows through the intermediate medium and the charge air, while and the first evaporator 15 flows through the refrigerant and the intermediate medium fluidly separated. Consequently, the circuit is also cold 9 and the fresh air system 3 fluidly completely separated from each other, so that a mixing of charge air and refrigerant and between intermediate medium and refrigerant or coolant is omitted. For heat transfer between the first evaporator 15 and the first intercooler 17 is thus the DC link 18 interposed, in which the intermediate medium flows. For circulating the intermediate medium in the DC link 18 is a DC link conveyor 19 provided, which drives the intermediate medium.

The refrigeration circuit 9 has for dividing the flow of the refrigerant between the first branch 13 and the second branch 14 a valve device 20 on, the following as a refrigerant circuit valve device 20 referred to as. The refrigeration circuit valve device 20 has a valve 21 on, in the first branch 13 is arranged. By opening and closing the valve 21 Thus, the flow of the refrigerant through the first branch 13 and consequently also through the second branch 14 to be controlled. In particular, it is thus possible, a flow of the refrigerant through the first branch 13 to interrupt. In this case, therefore, no active cooling of the intermediate medium by the first evaporator 15 ,

The cooling system 8th also has a charge air cooling circuit 22 on, in which a coolant circulates. For driving the coolant in the charge air cooling circuit 22 points the charge air cooling circuit 22 a conveyor 23 on. The charge air cooling circuit conveyor 23 and the DC link conveyor 19 can each be considered a compressor 24 be designed. The charge air cooling circuit 22 also has a second intercooler 25 for cooling the charge air as well as a coolant cooler 26 for cooling the coolant. Here is the charge air cooling circuit 22 fluidic from the refrigerant circuit 9 and from the DC link 18 separated. The second intercooler 25 is in the fresh air system 3 downstream of the compressor 5 and upstream of the first intercooler 17 arranged. In the example shown, the charge air cooling circuit 22 further configured such that it allows a permanent cooling of the charge air.

The fresh air system 3 has a bypass 27 or fresh air system bypass 27 on, the first intercooler 17 bypasses. This makes it possible, the charge air at least partially on the first intercooler 17 passing out. For this purpose, the fresh air system 3 a fresh air valve device 28 on, which is a division of the flow of charge air through the first intercooler 17 and at the first intercooler 17 allowed over. As a result, a regulation of the temperature of the charge air can be achieved that with increasing proportion of the first charge air cooler 17 flowing charge air a lower temperature of the engine 2 reaching charge air is achieved. For throttling the engine 2 reaching charge air is also a throttle device 29 provided downstream of the first intercooler 17 in the fresh air system 3 is arranged.

The vehicle 1 also has an engine cooling circuit 30 for cooling the internal combustion engine 2 on. In the engine cooling circuit 30 An engine coolant circulates through a heat exchanger 31 for cooling the engine and through an engine coolant radiator 32 for cooling the engine coolant. In addition, the engine cooling circuit 30 a the engine coolant radiator 32 immediate engine cooling circuit bypass 33 so that the circulation of the engine coolant by means of a motor cooling circuit valve device 34 at the engine coolant radiator 32 can be passed. Thus, a cooling of the internal combustion engine 2 , For example, in a warm-up phase of the internal combustion engine 2 , exposed or at least reduced.

Preferred are embodiments in which the charge air by means of the first intercooler 17 cooled to a lower temperature than by means of the second intercooler 25 ,

The refrigerant circuit compressor 10 is through a drive connection 35 with the internal combustion engine 2 connected. Thus, the refrigeration cycle compressor becomes 10 by the internal combustion engine 2 driven. For certain requirements, in particular for increased loads or an acceleration phase of the vehicle 1 , becomes the driving connection 35 between the internal combustion engine 2 and the refrigerant circuit compressor 10 separated, so that the entire performance of the internal combustion engine 2 is available for the required load or acceleration. In such a phase, the cooling of the charge air takes place with the aid of the first charge air cooler 17 only by the heat absorption of the intermediate medium in the DC link 18 or the cold stored in the DC link. In this case, a cooling of the intermediate medium through the first evaporator 15 by a reduced or interrupted circulation of the refrigerant in the refrigerant circuit 9 at least reduced.

The vehicle 1 has a fan 36 on, that a cooling air flow 37 generated by a wind of the vehicle 1 can be strengthened. The capacitor 11 of the refrigeration circuit 9 , the coolant cooler 26 of the charge air cooling circuit 22 and the engine coolant radiator 32 the engine cooling circuit 30 are arranged adjacent and parallel, such that the cooling air flow 37 the capacitor 11 , the coolant cooler 26 and the engine coolant radiator 32 flows in succession and / or flows past them and thus cools.

The refrigeration circuit 9 can also be used inside the vehicle 1 to achieve a different cooling. In particular, the refrigeration circuit 9 be used for a not shown air conditioning. For this comes the second evaporator 16 used, for example, an air flow 48 in an interior not shown here 49 of the vehicle 1 cools.

2 shows another embodiment of the vehicle 1 , Here is the engine cooling circuit 30 not shown. Unlike in 1 embodiment shown, the refrigeration cycle valve device 20 two valves 21 on, in each case such a valve 21 in the first branch 13 and in the second branch 14 is arranged.

The DC link 18 has a thermal mass capable of exchanging heat. The thermal mass therefore includes the first evaporator 15 , the first intercooler 17 , the intermediate medium, the DC link conveyor 19 as well as the connections between these components.

The thermal mass has an effect on how long the charge air through the first intercooler 17 in the case of an interruption of the cooling of the intermediate medium by the first evaporator 15 , can be further cooled. Accordingly, a vote of the DC link 18 , in particular by an appropriate choice of the volume, the thermal conductivity and the thermal Storage capacity influence can be taken on said duration, which corresponds to a predetermined time.

At the in 2 The example shown is a thermal storage device 38 provided, the at least partial storage or storage of intermediate medium and / or a thermal additional memory 39 serves. In this case, the additional thermal storage 39 or short additional storage 39 as latent heat storage 39 ' be designed or latent heat storage 39 ' exhibit. In this example, the storage device 38 and thus the additional thermal storage 39 or the latent heat storage 39 ' continuously in the DC link 18 involved. This leads to an increase in the thermal mass of the DC link 18 so that the cooling of the charge air through the first intercooler 17 without cooling the DC link 18 for a longer period of time and / or more efficiently. Said thermal mass is thus by the additional thermal storage 39 increased to achieve these benefits.

It is conceivable according to 3 also, the storage device 38 not continuously in the DC link 18 integrate. For this purpose, the memory device 38 with the help of a DC circuit valve device 42 fluidic and / or thermal with the DC link 18 connectable. In this case, the memory device 38 in a DC link bypass 43 of the DC link 18 arranged. The intermediate circuit valve device 42 has two valves 21 on, with one of the valves 21 upstream of the storage device 38 and the other valve 21 downstream of the storage device 38 in the intermediate circuit bypass 43 are arranged. This makes it possible, the additional thermal storage 39 by a corresponding actuation of the valves 21 arbitrarily in the DC link 18 or from the DC link 18 dissipate. In this example, it is further provided that the additional thermal storage 39 Intermediate medium has or corresponds to the intermediate medium. By introducing the additional memory 39 So is the thermal mass of the DC link 18 increased. Be both valves 21 the intermediate circuit valve device 42 opened, so is additional thermal storage 39 in the DC link 18 introduced. Be both valves 21 the intermediate circuit valve device 42 closed, so are the storage device 38 as well as the additional memory 39 fluidic and essentially thermal from the DC link 18 separated. When opening the upstream valve 21 the intermediate circuit valve device 42 and close the downstream valve 21 the intermediate circuit valve device 42 becomes additional thermal storage 39 , in particular intermediate medium, from the intermediate circuit 18 discharged and the storage device 38 saved. Here, the intermediate circuit valve device 42 advantageously in a suitable manner, for example by an electrical line, with the control device 40 connected so that they communicate with the controller 40 communicate and from the controller 40 can be controlled. The control device 40 is configured such that it provides the fluidic and / or thermal connection between the storage device 38 and the DC link 18 if necessary, so for example if no cooling of the DC link 18 and / or insufficient cooling of the charge air through the first intercooler 17 and / or the exceeding of a predetermined temperature of the intermediate medium, releases.

4 shows a variant in which no thermal storage device 38 is provided. In this variant, the additional thermal storage 39 , in particular the latent heat storage 39 ' , at least partially on the first intercooler 17 arranged or integrated. As a result, if necessary, an effective cooling of the first charge air cooler 17 and thus a corresponding effective cooling of the charge air through the first intercooler 17 ,

Alternatively or additionally, the additional thermal storage 39 , in particular the latent heat storage 39 ' , at least partially on the first evaporator 15 be arranged or integrated. In this way, in particular, an effective cooling of the first evaporator 15 and thus the intermediate medium if necessary.

An activation of the additional thermal storage 39 , in which the additional storage receives or cools heat, can be done in any way. Such activation may, as mentioned above, connect the thermal storage device 38 with the DC link 18 be. With latent heat storage 39 ' Activation can cause a phase transition. This activation can be done for example by an external operation. Alternatively or additionally, the activation in the exceeding of a predetermined temperature of the DC link 18 , in particular of the intermediate medium, are triggered automatically.

Charging the additional thermal storage 39 in which the additional memory 39 in particular emits heat or stores cold, preferably takes place when enough power is available for this purpose.

The vehicle 1 has the control device 40 on that the vehicle 1 , in particular the cooling system 8th or the internal combustion engine 2 controls. For this purpose, the control device 40 in a suitable manner, e.g. B. via electrical lines, communicating with the valve devices 20 . 28 . 34 . 42 connected. In addition, the control device 40 in a suitable manner, in particular by electrical lines, communicating with the drive connection 35 between the internal combustion engine 2 and the refrigerant circuit compressor 10 connected. The control device 40 is also equipped with measuring equipment 41 of the vehicle 1 or the cooling system 2 connected, the operating conditions and associated operating parameters of the vehicle 1 and the cooling system 8th determine. These include in particular temperatures of the vehicle, the charge air, the internal combustion engine 2 and the cooling system 8th , Is the vehicle 1 in a coasting phase, so no performance by the internal combustion engine 2 to drive the vehicle 1 needed. In such a boost phase, an associated thrust of the vehicle is used to the intermediate circuit 18 to cool, so that in subsequent phases improved heat absorption of the DC link 18 , in particular the intermediate medium and / or the additional thermal storage 39 , is possible. In particular, the charging or cooling of the additional memory 39 take place in such a push phase. By using the thrust performance so the duration can be extended, in which the charge air through the first intercooler 17 can be cooled without any cooling of the DC link 18 or the intermediate medium takes place. The cooling of the DC link 18 In such shear phases is preferably characterized in that the refrigerant circuit compressor 10 in such a deceleration phase of the vehicle 1 by the thrust of the vehicle 1 is driven. This causes the cooling of the DC link 18 without additional fuel consumption of the internal combustion engine 2 , In this case, a performance of the refrigerant compressor 10 or a compressor power in such a coasting phase of the vehicle 1 increase. For this purpose, it is conceivable, the drive connection 35 between the internal combustion engine 2 and the refrigerant circuit compressor 10 to reinforce. Also, the thrust of the vehicle 1 in addition to the drive by the internal combustion engine 2 be used to the circulation or conversion of the refrigerant in the refrigerant circuit 9 increase, thereby increasing the cooling capacity of the first evaporator 15 is reached.

Conversely, the drive connection 35 between the refrigerant circuit compressor 10 and the internal combustion engine 2 be interrupted when an increased power of the internal combustion engine 2 or a higher load of the internal combustion engine 2 is required. This is especially in an acceleration phase of the vehicle 1 before, in the then a greater power of the internal combustion engine 2 is available for acceleration.

A first cooling of the DC link 18 which is a prerequisite for cooling the charge air through the first intercooler 17 is dependent on operating parameters of the vehicle 1 , the cooling system 8th and the internal combustion engine 2 , These operating parameters are determined by the measuring devices 41 determined. It can be provided in particular that the intermediate circuit 18 first cooled when the internal combustion engine 2 is operated for a predetermined time in a load operation. In such a load operation are higher power of the internal combustion engine 2 required, which in turn require a strong cooling of the charge air. Accordingly, the DC link 18 first cooled when the internal combustion engine 2 in such a load operation, or is operated for a predetermined time. Thus, therefore, there is also a first cooling of the charge air through the first charge air cooler 17 when the internal combustion engine 2 is first in a load operation or operated for a predetermined time in such a load operation.

Alternatively, a first-time cooling of the DC link 18 then take place when a load operation of the internal combustion engine 2 is to be expected. This can be the case, for example, if a speed of the internal combustion engine 2 has a positive gradient. This is a sign that higher power and thus loads of the internal combustion engine 2 are expected or required, so that a stronger cooling of the charge air is needed. This stronger cooling is achieved by the first intercooler 17 or the DC link 18 provided by the refrigerant circuit 9 is cooled. Accordingly, the DC link 18 cooled for the first time when the speed has such a positive gradient.

In a further alternative, the first cooling of the DC link takes place 18 after a start of operation of the internal combustion engine 2 when a load operation of the internal combustion engine is signaled. In particular, such signaling can be achieved by setting an associated operating mode, for example a sports mode of the vehicle 1 , respectively. In this case, so is a quick response of the internal combustion engine 2 also desired immediately after the start of operation, in particular better acceleration of the vehicle 1 to reach. This requires sufficient cooling of the charge air through the first intercooler 17 is realized. Accordingly, the first cooling of the DC link takes place 18 through the refrigeration circuit 9 when selecting or setting such an operating mode. In this case, the operating mode before the start of operation of the internal combustion engine 2 be set so that a first cooling of the DC link 18 immediately after the start of operation or after a predetermined time after the start of operation.

For initial cooling of the DC link 18 becomes the first branch 13 flows through the refrigerant. For initial cooling of the DC link 18 can therefore the refrigerant circuit valve device 20 are used, for the first time flow through the first evaporator 15 is controlled by the refrigerant accordingly. For this purpose, the refrigeration circuit valve device 20 in any manner, for example by electrical conductors, communicating with the control device 40 connected to the refrigerant circuit valve device 20 makes a corresponding adjustment.

5 shows another embodiment of the vehicle 1 , This embodiment differs from that in FIG 2 shown embodiment in particular in that no memory device 38 and in the fresh air system 3 and no bypass 27 to bypass the first intercooler 17 are provided. In addition, the first intercooler 17 a first cooling stage 44 and a second cooling stage 45 on. The first cooling stage 44 is in the fresh air system 3 before the second cooling stage 45 , ie upstream of the second cooling stage 45 arranged. In the intermediate circuit 18 the arrangement is reversed: the second cooling stage 45 is upstream of the first cooling stage 44 arranged. The charge air is in the first intercooler 17 So first of the first cooling stage 44 and then from the second cooling stage 45 cooled by the arrangement of the cooling stages 44 . 45 in the intermediate circuit 18 the charge air in the second cooling stage 45 cooled to a lower temperature than in the first cooling stage 44 ,

The first intercooler 17 also has a separator 46 up in the fresh air plant 3 between the first cooling stage 44 and the second cooling stage 45 is arranged. The separator 46 serves the purpose of condensate from the fresh air system 3 , in particular the charge air, to separate, which may arise from the cooling of the charge air. As a result, it is thus prevented that condensate, which may in particular have water and / or oil, enters the internal combustion engine 2 arrives and causes damage there.

In the process, the cooling system becomes 8th preferably operated such that by the first cooling stage 44 cooling the charge air to a first temperature, which is above 0 ° C. This ensures in particular that no crystallization or icing of the condensate occurs. Subsequently, the deposition of the condensate takes place in the separator 46 , followed by the cooling of the charge air in the second cooling stage 45 to a second temperature that is less than that due to the cooling in the first cooling stage 44 reached, first temperature. Preferably, the cooling of the charge air and the deposition of the condensate takes place such that the charge air after cooling in the first cooling stage 44 a maximum relative humidity, ie 100% relative humidity, has. This ensures the most efficient cooling of the charge air without the formation of condensate.

Preferably, the charge air is in the second cooling stage 45 cooled to a temperature below 0 ° C. This means that the second temperature is below 0 ° C. This can fuel savings or emission reductions of the internal combustion engine 2 be achieved.

Operating the internal combustion engine 2 preferably takes place by means of the control device 40 , which is designed to be the components of the vehicle 1 can control and operate.

The integration of the first cooling stage 44 and the second cooling stage 45 in the first intercooler 17 leads to a reduction in the required installation space. The same applies to the integration of the separator 46 in the first intercooler 17 , This also allows the number of components required for the production of the cooling system 8th be reduced. Furthermore, the efficiency of cooling the charge air and the removal of condensate is increased because energy losses are reduced.

Claims (10)

Method for operating a supercharged internal combustion engine ( 2 ), preferably in a vehicle ( 1 ), - with a cooling circuit ( 9 ), in which a refrigerant circulates and a refrigerant circuit compressor ( 10 ) for driving the refrigerant and a first evaporator ( 15 ) for vaporizing the refrigerant, - with a fresh air system ( 3 ) for supplying fresh air to the internal combustion engine ( 2 ), in which a compressor ( 5 ), the fresh air plant ( 3 ) a first intercooler ( 17 ) for cooling the compressor ( 5 ) has compressed charge air, - with a DC link ( 18 ), in which an intermediate medium circulates and in which the first evaporator ( 15 ) and the first intercooler ( 17 ) are heat-transferring involved, - wherein the intermediate circuit ( 18 ) fluidly from the refrigerant circuit ( 9 ) and the fresh air system ( 3 ), the intermediate circuit ( 18 ) after a start of operation of the internal combustion engine ( 2 ) for the first time depending on operating parameters of the internal combustion engine ( 2 ) and / or an associated vehicle ( 1 ) is cooled. Method according to Claim 1, characterized in that the intermediate circuit ( 18 ) to a start of operation of the internal combustion engine ( 2 ) is cooled for the first time when the internal combustion engine ( 2 ) is operated for a predetermined time in a load operation. Method according to Claim 1, characterized in that the intermediate circuit ( 18 ) after a start of operation of the internal combustion engine ( 2 ) is cooled when a load operation of the internal combustion engine ( 2 ) is to be expected. Method according to one of claims 1 to 3, characterized in that the intermediate circuit ( 18 ) after the start of operation of the internal combustion engine ( 2 ) is cooled for the first time when a gradient of a speed of the internal combustion engine ( 2 ) is positive and exceeds a predetermined value. Method according to one of Claims 1 to 4, characterized in that the intermediate circuit ( 18 ) is cooled for the first time when an associated operating mode is set. Charged internal combustion engine ( 2 ), preferably a vehicle ( 2 ), - with a cooling circuit ( 9 ), in which a refrigerant circulates and a refrigerant circuit compressor ( 10 ) for driving the refrigerant and a first evaporator ( 15 ) for vaporizing the refrigerant, - with a fresh air system ( 3 ) for supplying fresh air to the internal combustion engine ( 2 ), in which a compressor ( 5 ), the fresh air plant ( 3 ) a first intercooler ( 17 ) for cooling the compressor ( 5 ) has compressed charge air, - with a DC link ( 18 ), in which an intermediate medium circulates and in which the first evaporator ( 15 ) and the first intercooler ( 17 ) are heat-transferring involved, - wherein the intermediate circuit ( 18 ) fluidly from the refrigerant circuit ( 9 ) and the fresh air system ( 3 ) is separated, - wherein a control device ( 40 ) is provided, which operates the internal combustion engine according to a method according to one of claims 1 to 5. Internal combustion engine according to claim 6, characterized in that - the cooling circuit ( 9 ) a first branch ( 13 ) and a second branch ( 14 ), wherein the cooling circuit ( 9 ) downstream of a capacitor ( 11 ) of the refrigeration circuit ( 9 ) in the two branches ( 13 . 14 ) branches off and the two branches ( 13 . 14 ) upstream of the capacitor ( 11 ) - that the first evaporator ( 15 ) in the first branch ( 13 ) - that in the second branch ( 14 ) a second evaporator ( 16 ) is arranged. Internal combustion engine according to claim 7, characterized by a refrigeration circuit valve device ( 20 ) for dividing the flow of the refrigerant between the first branch ( 13 ) and the second branch ( 14 ). Internal combustion engine according to one of claims 6 to 8, characterized in that the intermediate circuit ( 18 ) a conveyor ( 19 ), in particular a DC link compressor ( 24 ), for driving the intermediate medium. Internal combustion engine according to one of claims 6 to 9, characterized in that the cooling system ( 8th ) a fluidic of the refrigerant circuit ( 9 ) and the fresh air system ( 3 ) as well as from the DC link ( 18 ) separate charge air cooling circuit ( 22 ), in which a coolant circulates and the one in the fresh air system ( 3 ) upstream of the first intercooler ( 17 ) arranged second intercooler ( 25 ) for cooling the charge air and a coolant radiator ( 26 ) for cooling the coolant.

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