DE102017200796A1 - Internal combustion engine with electrically driven compressor in the intake system and method for starting such an internal combustion engine - Google Patents

Abstract

The invention relates to an internal combustion engine (10) having at least one cylinder head comprising at least one cylinder (1, 2, 3, 4), in which each cylinder (1, 2, 3, 4) has at least one inlet opening, to which a suction line for supplying air via intake system (5), - each cylinder (1, 2, 3, 4) has at least one outlet opening, to which an exhaust pipe for discharging the exhaust gases via Abgasabführsystem (6) connects, - at least one exhaust gas recirculation (13 An electrically drivable compressor (8) is arranged in the intake system (5). An internal combustion engine (10) of the type mentioned is to be provided, with which an improved cold start behavior can be realized. This object is achieved by an internal combustion engine (10) of the said type, characterized in that a first bypass line (9) is provided downstream of the electrically driven compressor (8) to form a It branches off the first node (9a) from the intake system (5) and opens upstream of the electrically driven compressor (8) to form a second node (9b) in the intake system (5).

Description

• - jeder Zylinder mindestens eine Einlassöffnung aufweist, an die sich eine Ansaugleitung zum Zuführen von Luft via Ansaugsystem anschließt,
• - jeder Zylinder mindestens eine Auslassöffnung aufweist, an die sich eine Abgasleitung zum Abführen der Abgase via Abgasabführsystem anschließt,
• - mindestens eine Abgasrückführung vorgesehen ist, und
• - ein elektrisch antreibbarer Verdichter im Ansaugsystem angeordnet ist.

The invention relates to an internal combustion engine having at least one cylinder head comprising at least one cylinder, in which

• each cylinder has at least one inlet opening, followed by an intake line for supplying air via the intake system,
• each cylinder has at least one outlet opening adjoined by an exhaust pipe for discharging the exhaust gases via the exhaust gas removal system,
• - At least one exhaust gas recirculation is provided, and
• - An electrically drivable compressor is arranged in the intake system.

Furthermore, the invention relates to a method for starting such an internal combustion engine.

An internal combustion engine of the type mentioned is used as a motor vehicle drive. In the context of the present invention, the term internal combustion engine includes diesel engines, but also gasoline engines and hybrid internal combustion engines, d. H. Internal combustion engines, which are operated with a hybrid combustion process, and hybrid drives, which in addition to the internal combustion engine include a drive motor-connectable with the electric motor, which receives power from the internal combustion engine or emits additional power as a switchable auxiliary drive.

Internal combustion engines are increasingly equipped with a charge, the charge is primarily a method of increasing performance, in which the charge air required for the engine combustion process is compressed, whereby each cylinder per cycle a larger charge air mass can be supplied. As a result, the fuel mass and thus the medium pressure can be increased.

The charge is a suitable means to increase the capacity of an internal combustion engine with unchanged displacement or to reduce the displacement at the same power. In any case, the charging leads to an increase in space performance and a lower power mass. If the cubic capacity is reduced, the load spectrum can be shifted to higher loads at the same vehicle boundary conditions, where the specific fuel consumption is lower. The charging of an internal combustion engine thus supports the efforts to minimize fuel consumption, d. H. to improve the efficiency of the internal combustion engine.

By means of a suitable transmission design, a so-called downspeeding can additionally be realized, as a result of which a lower specific fuel consumption is likewise achieved. Downspeeding exploits the fact that the specific fuel consumption at low speeds is regularly lower, especially at higher loads.

With targeted design of the charge also benefits in the exhaust emissions can be achieved. Thus, by means of suitable charging, for example in the diesel engine, the nitrogen oxide emissions can be reduced without sacrificing efficiency. At the same time, the hydrocarbon emissions can be favorably influenced. The emissions of carbon dioxide, which correlate directly with fuel consumption, also decrease with decreasing fuel consumption.

Frequently, an exhaust gas turbocharger is used for charging, in which a compressor and a turbine are arranged on the same shaft. The hot exhaust stream is supplied to the turbine and relaxes with energy release in the turbine, causing the shaft to rotate. The energy emitted by the exhaust gas flow to the turbine and finally to the shaft is used to drive the compressor, which is also arranged on the shaft. The compressor conveys and compresses the charge air supplied to it, whereby a charging of the cylinder is achieved. Advantageously, a charge air cooler is provided downstream of the compressor in the intake system, with which the compressed charge air is cooled before entering the cylinder. The radiator lowers the temperature and thus increases the density of the charge air, so that the cooler to a better filling of the cylinder, d. H. contributes to a larger air mass. There is a compaction by cooling.

The advantage of an exhaust gas turbocharger in comparison to a supercharger which is driven by means of an auxiliary drive is that an exhaust gas turbocharger uses the exhaust gas energy of the hot exhaust gases, while a supercharger obtains the energy required for its drive directly or indirectly from the internal combustion engine and thus, at least as long the drive energy does not come from an energy recovery, adversely affects the efficiency, d. H. decreases.

If it is not an electric machine, d. H. is electrically driven supercharger or compressor is regularly a mechanical or kinematic connection for power transmission between the supercharger and the internal combustion engine is required, which also adversely affects or determines the packaging in the engine compartment.

The advantage of a supercharger drivable by means of an auxiliary drive compared to an exhaust gas turbocharger, in turn, is that the supercharger can always generate and provide the required boost pressure, and indeed almost instantaneously and independently of the operating state of the internal combustion engine. This is especially true for a loader that is electrically driven by electric motor and therefore independent of the speed of the crankshaft.

In fact, according to the state of the art, it is difficult to increase the power by means of turbocharging in all engine speed ranges and, in particular, without delay. It is observed a greater torque drop when falling below a certain speed. This torque drop becomes understandable if it is taken into account that the boost pressure ratio depends on the turbine pressure ratio or the turbine output. If the engine speed is reduced, this leads to a smaller exhaust gas mass flow and thus to a smaller turbine pressure ratio or a smaller turbine power. Consequently, the boost pressure ratio also decreases toward lower speeds. This is synonymous with a torque drop.

A supercharged by turbocharging internal combustion engine suffers in principle that at an increased load requirement, first the turbine power must be increased in order to provide the required drive power for the compressor can. This leads in the transient operation of the internal combustion engine to a certain delay effect, which is undesirable.

The internal combustion engine, which is the subject of the present invention, has at least one electrically drivable compressor and is thus at least one rechargeable internal combustion engine, preferably a supercharged internal combustion engine. Therefore, a cooler optionally provided in the intake system is also referred to as a charge air cooler and the air supplied via the intake system is also referred to as charge air.

In the development of internal combustion engines, efforts are constantly being made to minimize fuel consumption. In addition, the aim is to reduce pollutant emissions in order to be able to comply with future limit values for pollutant emissions.

In order to achieve the above-mentioned objectives, additional measures are required in addition to any charge made, for example, the return of hot exhaust gases from the exhaust side to the inlet side, whereby the nitrogen oxide emissions can be reduced. In order to achieve a significant reduction in nitrogen oxide emissions, high exhaust gas recirculation rates are required.

In order to reduce the fuel consumption and thus also the pollutant emissions, it makes sense in principle to minimize the friction of an internal combustion engine.

With regard to the reduction of friction losses, rapid heating of the engine oil and rapid heating of the internal combustion engine, especially after a cold start, are expedient. Rapid heating of the engine oil during the warm-up phase of the internal combustion engine ensures a correspondingly rapid decrease in viscosity and thus a reduction in the friction or friction power, especially in the oil-supplied bearings.

The rapid heating of the engine oil is forced by a rapid heating of the internal combustion engine as such. Therefore, in a liquid-cooled internal combustion engine during the warm-up phase or after a cold start, a no-flow strategy is regularly implemented, according to which a circulation of the coolant is prevented in order to prevent the heat dissipation due to convection. In addition, the standing in the coolant channels or coolant shells coolant heats faster under a no-flow strategy, since the registered in the cylinder head and / or cylinder block in the coolant heat is not removed from the coolant in a heat exchanger again. The warmer coolant ensures when releasing the coolant circulation in turn for faster heating of the rest or entire internal combustion engine.

Despite the concepts described above, further measures are required to improve the cold start behavior of an internal combustion engine.

Against the background of the above, it is an object of the present invention to provide an internal combustion engine according to the preamble of claim 1, with which an improved cold start behavior can be realized.

Another object of the present invention is to provide a method for starting such an internal combustion engine.

• - jeder Zylinder mindestens eine Einlassöffnung aufweist, an die sich eine Ansaugleitung zum Zuführen von Luft via Ansaugsystem anschließt,
• - jeder Zylinder mindestens eine Auslassöffnung aufweist, an die sich eine Abgasleitung zum Abführen der Abgase via Abgasabführsystem anschließt,
• - mindestens eine Abgasrückführung vorgesehen ist, und
• - ein elektrisch antreibbarer Verdichter im Ansaugsystem angeordnet ist,

und die dadurch gekennzeichnet ist, dass eine erste Bypassleitung vorgesehen ist, die stromabwärts des elektrisch antreibbaren Verdichters unter Ausbildung eines ersten Knotenpunktes vom Ansaugsystem abzweigt und stromaufwärts des elektrisch antreibbaren Verdichters unter Ausbildung eines zweiten Knotenpunktes in das Ansaugsystem einmündet.The first sub-task is solved by an internal combustion engine with at least one cylinder head comprising at least one cylinder in which

• - each cylinder has at least one inlet opening, followed by a suction line for supplying air via the intake system,
• each cylinder has at least one outlet opening adjoined by an exhaust pipe for discharging the exhaust gases via the exhaust gas removal system,
• - At least one exhaust gas recirculation is provided, and
• an electrically drivable compressor is arranged in the intake system,

and which is characterized in that a first bypass line is provided, which branches off downstream of the electrically driven compressor to form a first node of the intake system and opens upstream of the electrically driven compressor to form a second node in the intake system.

The internal combustion engine according to the invention is equipped with an electrically driven compressor, which may in principle also be used to charge the internal combustion engine, but according to the invention primarily serves the purpose of entering in a non-heated internal combustion engine in a startup process by means of compression heat in the air in the intake system, so that in the intake system heated air, d. H. Air at elevated temperature, circulated or provided. As a result, the intake system can be heated as such or heated or warmed air can be supplied to the at least one cylinder of the internal combustion engine when starting.

As a result, in particular, the cylinder-limiting components and components can be heated, namely the cylinder block, the cylinder-associated piston, the cylinder head, the cylinder-related control elements for the gas exchange and the adjoining the cylinder Abgasabführsystem complete with exhaust aftertreatment systems.

However, air is supplied to the at least one cylinder when starting only when the electrically drivable compressor is activated and operated, while the crankshaft of the internal combustion engine is forcibly rotated using a starting device or the internal combustion engine is fired and actuates the valve trains as a result of the crankshaft rotation and release the cylinder-associated openings for gas exchange.

The internal combustion engine according to the invention is equipped with a first bypass line, which serves to promote or circulate the heated air by means of the electrically driven compressor in a circle.

For this purpose, the first bypass line branches off downstream of the electrically driven compressor to form a first node from the intake system and flows upstream of the electrically driven compressor to form a second node in the intake system.

The electrically driven compressor heats the air in the intake system as part of the compression and conveys the heated air via the bypass line back to its suction side, d. H. at its entrance, and / or leads the heated air via the intake system to the at least one cylinder of the internal combustion engine.

The electrically drivable compressor is characterized in that its drive power is not provided directly or at the same time by the internal combustion engine, which is why the electrically drivable compressor can also be used for compression or for heat input when the internal combustion engine is switched off, is not fired or the crankshaft is stationary.

The electrically drivable compressor is switched off as soon as the above-described requirement no longer exists.

The electrically driven compressor can also be used in normal operation of the internal combustion engine to improve the transient operating behavior of the internal combustion engine and the torque characteristic at low speeds or small amounts of exhaust gas.

In normal operation of the internal combustion engine, the first bypass line can again be used to bypass the electrically driven compressor, wherein the air is then optionally taken from the intake system upstream of the electrically driven compressor and fed back downstream of the electrically driven compressor.

With regard to the charging of an internal combustion engine in operation, the advantage of the electrically driven compressor is that the electrically driven compressor - in contrast to the exhaust gas turbocharger - can generate and provide the required charge pressure regardless of the current operating state of the internal combustion engine, especially with low amounts of exhaust gas or Low speed of the crankshaft and this request almost instantaneous.

With the internal combustion engine according to the invention an internal combustion engine according to the preamble of claim 1 is provided, with which an improved cold start behavior can be realized. Thus, the first object of the invention is solved.

According to the invention, at least one exhaust gas recirculation is provided, which comprises a return line, which branches off from the exhaust gas removal system and opens into the intake system. The exhaust gas recirculation, d. H. the recirculation of combustion gases, is a suitable means to reduce the nitrogen oxide emissions, and with increasing exhaust gas recirculation rate, the nitrogen oxide emissions can be significantly reduced.

When operating an internal combustion engine with turbocharging a conflict may arise if at the same time an exhaust gas recirculation is used because - depending on the arrangement of the return line - the recirculated exhaust gas is optionally taken upstream of the turbine from the Abgasabführsystem and is no longer available to drive the turbine ,

With an increase in the exhaust gas recirculation rate then decreases the remaining of the turbine exhaust gas flow supplied. The smaller exhaust gas mass flow through the turbine leads to a smaller turbine pressure ratio. With decreasing turbine pressure ratio, the boost pressure ratio also decreases, which is synonymous with a smaller compressor mass flow. In addition to the decreasing boost pressure, additional problems may arise in the operation of the compressor of the exhaust gas turbocharger with regard to the surge limit of the compressor.

For this reason, supercharging concepts are required which ensure sufficiently high charge pressures and at the same time high exhaust gas recirculation rates, in particular in the partial load range. The part-load range is of high relevance, in particular due to the statutory exhaust gas tests required for the determination of pollutant emissions. In principle, however, sufficiently high boost pressures and high exhaust gas recirculation rates are aimed at under all operating conditions.

Further advantageous embodiments of the internal combustion engine are discussed in connection with the subclaims.

Embodiments of the internal combustion engine in which the first bypass line is equipped with a first shut-off element are advantageous.

The first shut-off allows by opening the release of the first bypass line and thus the return of heated air by means of electrically driven compressor, if the heated air is to circulate. With this shut-off element, in particular, the amount of air recirculated by means of electrically driven compressors can be controlled, ie. H. set, and thus also the at least one cylinder of the internal combustion engine optionally supplied amount of air.

Embodiments of the internal combustion engine in which a charge air cooler is arranged in the intake system downstream of the electrically drivable compressor are advantageous.

In principle, the electrically drivable compressor can be arranged downstream or upstream of an intercooler, wherein the electrically drivable compressor is preferably arranged upstream of the intercooler, so that the compressor-compressed air during normal operation of the internal combustion engine, when the internal combustion engine is to be charged before entering the at least one cylinder in the intercooler can be cooled.

Advantageous in this context are embodiments of the internal combustion engine in which a second bypass line is provided which branches off upstream of the charge air cooler to form a third node from the intake system and opens downstream of the intercooler to form a fourth node in the intake system.

The second bypass line allows the bypass of the charge air cooler, if the compressed or heated air is not to be cooled, for example, after a cold start or in the warm-up phase of the internal combustion engine.

Embodiments of the internal combustion engine in which the second bypass line is equipped with a second shut-off element are advantageous.

The second shut-off allows by opening the release of the second bypass line and thus bypassing the intercooler, if the heated air should not be cooled. With this shut-off can be controlled by the intercooler guided air flow, d. H. to adjust.

In this context, embodiments of the internal combustion engine may be advantageous in which the second shut-off element is arranged at the third node and at the same time reduces or completely suppresses the inflow to the intercooler when the second bypass line is released.

If the internal combustion engine has an intercooler, which is arranged downstream of the electrically driven compressor in the intake system, embodiments may be advantageous in which the first bypass line branches off from the intake system upstream of the intercooler, forming a first node.

If the internal combustion engine has an intercooler, which is arranged downstream of the electrically driven compressor in the intake system and equipped with a second bypass line, embodiments may be advantageous in which the first bypass line branches off from the second bypass line to form a first node.

If the internal combustion engine has an intercooler, which is arranged downstream of the electrically driven compressor in the intake system and equipped with a second bypass line, embodiments may also be advantageous in which the first bypass line branches off downstream of the intercooler to form a first node from the intake system.

The three embodiments described above all allow the air heated by means of electrically driven compressors, without being cooled in the charge air cooler, to be returned to the inlet side or suction side of the electrically driven compressor, i. H. is introduced upstream of the electrically driven compressor in the intake system.

Branches the first bypass line downstream of the intercooler to form a first node from the intake from, it makes sense for this purpose to pass the heated air previously via the second bypass line to the charge air cooler over.

Embodiments of the internal combustion engine in which at least one exhaust-gas turbocharger is provided, which comprises a turbine arranged in the exhaust-gas removal system and a compressor arranged in the intake system, are advantageous. With regard to the exhaust gas turbocharger, reference is made to the statements already made.

The torque characteristic of an exhaust-gas-charged internal combustion engine can be improved by various measures.

For example, by a small design of the turbine cross-section and simultaneous Abgasabblasung. Such a turbine is also referred to as a waste gate turbine. If the exhaust gas mass flow exceeds a critical size, part of the exhaust gas flow is conducted past the turbine by means of a bypass line as part of the so-called exhaust gas blow-off. This approach has the disadvantage that the charging behavior at higher speeds or larger amounts of exhaust gas is less satisfactory.

The torque characteristic can also be advantageously influenced by means of a plurality of exhaust-gas turbochargers connected in series. By switching in series of two exhaust gas turbochargers, one of which is an exhaust gas turbocharger as a high pressure stage and an exhaust gas turbocharger as a low pressure stage, the engine map or compressor map can be widened in an advantageous manner both towards smaller compressor streams and towards larger compressor streams.

In particular, in the case of the exhaust gas turbocharger serving as a high-pressure stage, the pumping limit can be shifted towards smaller compressor flows, which means that high boost pressure ratios can be achieved even with small compressor flows, which significantly improves the torque characteristic in the lower rpm range. This is achieved by designing the high-pressure turbine for small exhaust gas mass flows and providing a bypass line, with which increasing exhaust gas mass flow increasingly exhaust gas is passed to the high-pressure turbine. For this purpose, the bypass line branches off from the exhaust-gas removal system upstream of the high-pressure turbine and flows back into the exhaust-gas removal system upstream of the low-pressure turbine, wherein a shut-off element is arranged in the bypass line in order to control the exhaust gas flow conducted past the high-pressure turbine.

The downsizing is continued by a multi-stage turbocharger charge. Furthermore, the response of such a supercharged internal combustion engine is significantly improved over a comparable internal combustion engine with single-stage charging, since the smaller high-pressure stage is less sluggish and can accelerate the running gear of a smaller sized exhaust gas turbocharger faster.

The torque characteristic of a supercharged internal combustion engine may be further characterized by a plurality of turbochargers arranged in parallel, i. H. be improved by a plurality of parallel turbines with a smaller turbine cross-section, with turbines are switched successively with increasing exhaust gas.

Embodiments of the internal combustion engine in which the turbine of the at least one exhaust-gas turbocharger has a fixed turbine geometry are advantageous. A solid turbine geometry is inexpensive. For a satisfactory torque characteristic, it may be useful to run the turbine as a waste gate turbine.

Embodiments of the internal combustion engine in which the turbine of the at least one exhaust gas turbocharger has a variable turbine geometry are also advantageous.

A variable turbine geometry increases the flexibility of charging. It allows a stepless adjustment of the turbine geometry to the respective operating point of the internal combustion engine or to the current exhaust gas mass flow. In this case, upstream of the impeller of the turbine vanes for influencing the flow direction are arranged. Unlike the blades of the rotating impeller, the vanes do not rotate with the shaft of the turbine, i. H. the impeller. Although the guide vanes are arranged stationary, but not completely immobile, but rotatable about its axis, so that the flow of the blades can be influenced.

On the other hand, if a turbine has a fixed invariable geometry, the vanes are not only stationary but also completely immovable, i. H. rigidly fixed, as far as guide vanes are provided or a guide is provided.

In particular, the combination of turbine with variable turbine geometry and compressor with variable compressor geometry allows to achieve high boost pressures even with very small amounts of exhaust gas.

Therefore, embodiments of the internal combustion engine in which the compressor of the at least one exhaust-gas turbocharger has a variable compressor geometry are also advantageous. In particular, if only a small amount of exhaust gas is passed through the turbine, a variable compressor geometry proves to be advantageous because the pumping limit of the compressor can be moved by adjusting the vanes in the compressor map to small compressor streams and so working the compressor is avoided beyond the surge line. The variable compressor geometry therefore also offers advantages when large amounts of exhaust gas are branched off and returned upstream of the turbine in order to achieve high return rates. If the turbine of the at least one exhaust-gas turbocharger has a variable turbine geometry, the variable compressor geometry can be continuously matched to the turbine geometry.

In exhaust-gas-charged internal combustion engines, embodiments are advantageous in which the electrically drivable compressor is arranged downstream of the compressor of the at least one exhaust-gas turbocharger in the intake system. Then the electrically driven compressor does not have to promote the heated air through the compressor of the at least one exhaust gas turbocharger.

If the electrically drivable compressor is not arranged upstream, but downstream of the compressor of the at least one exhaust-gas turbocharger, the electrically drivable compressor can serve as a high-pressure stage in the context of a two-stage compression or charging.

In this connection, embodiments of the internal combustion engine in which the first bypass line between the electrically drivable compressor and the compressor of the at least one exhaust gas turbocharger opens into the intake system to form the second node point are advantageous.

In the case of equipping the internal combustion engine with a charge air cooler, embodiments are advantageous in which a collecting container for condensate in the intake system is arranged downstream of the charge air cooler. The container is for collecting condensate, d. H. of liquid water, and thus the removal of water from the rest of the intake system, which can eliminate the problems resulting from the formation of condensation. Eliminated condensate is taken from the charge air flow due to kinetics and discharged or deposited in the collecting container.

The water in the collecting tank can - like the water in the intercooler - freeze. In contrast to the formation of ice in the intercooler icing in the collection container but are not critical, since they can cause any blockage of the intake or damage to the collection container. Ice deposits in the collecting container can not lead to an increased pressure loss in the intake system. The latter is particularly relevant in supercharged internal combustion engines of relevance in which a pressure drop in the intake downstream of the at least one compressor is equivalent to a boost pressure reduction or boost pressure loss, which is undesirable in the context of charging the engine and counteracts an effective charge.

Embodiments of the internal combustion engine in which the charge air cooler is self-draining are advantageous, which ensures that no condensate accumulates in the cooler.

In this context, embodiments of the internal combustion engine in which the intercooler is inclined in the installed position of the internal combustion engine are advantageous. According to this embodiment, the intercooler is set at an angle, so that a gradient between the inlet and outlet is formed and the transport of a Condensate is already gravity assisted in the cooler, to counteract any accumulation. With regard to the angle α, reference is made here to a virtual straight line set by the entry and the exit.

If the charge air cooler is self-draining, embodiments may therefore also be advantageous in which an entry into the charge air cooler in the installation position of the internal combustion engine is arranged at a higher geodetic level than an exit from the charge air cooler.

This embodiment of the intercooler ensures that the advantages of the inventive concept are fully realized and no condensate accumulates in the radiator, because the outlet has a greater geodetic height than the entrance.

If the internal combustion engine is charged by turbocharging, embodiments are advantageous in which the electrically driven compressor is designed smaller than the compressor of the at least one exhaust gas turbocharger.

This is advantageous in particular in embodiments in which the electrically drivable compressor is arranged downstream of the compressor of the at least one exhaust gas turbocharger in the intake system and can be used as a high-pressure stage in the context of a two-stage compression. In addition, a small or smaller dimensioned electric compressor is usually sufficient for the primary purpose of this compressor according to the invention, namely to heat air.

Embodiments of the internal combustion engine in which only one exhaust-gas turbocharger is provided are advantageous. With respect to the frictional power and the overall efficiency, it is more advantageous to use a single exhaust gas turbocharger instead of a plurality of turbochargers, and therefore, the above embodiment has advantages in efficiency. There are also cost advantages and advantages in packaging. It should also be noted in this context that the electrically driven compressor is basically ready for charging, d. H. can be switched on if necessary, which is why only one exhaust gas turbocharger can be sufficient.

Embodiments of the internal combustion engine in which a sensor is provided for the metrological detection of the temperature of the air in the intake system are advantageous. The metrologically detected air temperature can be used as input for controlling the first shut-off element provided in the first bypass line and / or the drive power of the electrically driven compressor and / or serve as a decision criterion for whether the heated air is conveyed in the intake system in a circle or at least a cylinder is supplied.

The second sub-task on which the invention is based, namely to disclose a method for starting an internal combustion engine of the type described above, is achieved by a method in which the electrically drivable compressor is operated in the course of a cold start in order to transfer heat to the compressor driven by the electric drivable compressor Enter air and thus into the air in the intake system.

What has already been said for the internal combustion engine according to the invention also applies to the method according to the invention, which is why reference is generally made at this point to the statements made above with regard to the internal combustion engine. The various internal combustion engines sometimes require different process variants.

For operating an internal combustion engine with crankshaft and starting device embodiments of the method are advantageous in which the electrically driven compressor is activated and operated before the starting device is activated to forcibly set the crankshaft in rotation. The heating of the air in the intake system and the intake system itself together with the electrically driven compressor is then at least a preparatory measure before the actual starting process or a preparation of the starting process before the starting device forcibly sets the crankshaft in rotation.

However, embodiments of the method in which the electrically drivable compressor continues to operate while the crankshaft is forcibly rotated by means of a starting device are advantageous. In the present case, the electrically drivable compressor is already activated and operated before the starting device is activated, and is further operated when the crankshaft forcibly rotates the crankshaft.

For operating an internal combustion engine with crankshaft and starting device and embodiments of the method may be advantageous in which the electrically driven compressor is activated and operated, while the crankshaft is forcibly set in rotation by means of starting device. In the present case, the electrically drivable compressor is only activated and operated when the starting device already forcibly sets the crankshaft in rotation.

For operating an internal combustion engine, wherein the first bypass line with a first Embodiment of the method may be advantageous, which are characterized in that a boost pressure in the intake system downstream of the electrically driven compressor and the amount of air supplied to the at least one cylinder using a drive line of the electrically driven compressor and / or an opening degree of first shutters.

Embodiments of the method in which the air temperature T _air in the intake system is controlled using the electrically drivable compressor and / or a sensor and / or the first shut-off element are advantageous.

Advantageous embodiments of the method in which the electrically driven compressor is turned off when or as soon as the internal combustion engine is fired.

• 1 schematisch eine erste Ausführungsform der Brennkraftmaschine.

The invention will be explained in greater detail below with reference to an embodiment of an internal combustion engine and according to FIG. Hereby shows:

• 1 schematically a first embodiment of the internal combustion engine.

1 schematically shows a first embodiment of the internal combustion engine 10 that with an exhaust gas turbocharger 7 equipped, the one in the exhaust system 6 arranged turbine 7a and one in the intake system 5 arranged compressor 7b includes.

It is a four-cylinder in-line engine 10 in which the four cylinders 1 . 2 . 3 . 4 along the longitudinal axis of the cylinder head, that are arranged in series. The exhaust pipes of the cylinders 1 . 2 . 3 . 4 forming an exhaust manifold together to form an overall exhaust line leading to the turbine 7a the exhaust gas turbocharger 7 leads. The hot exhaust gas relaxes in the turbine 7a under energy release.

The compressor 7b compresses the charge air, which in normal operation via intake system 5 and downstream intercooler 11 the cylinders 1 . 2 . 3 . 4 can be supplied, whereby a charge of the fired internal combustion engine 10 is reached. The intercooler 11 is integral with the plenum 5a trained or in the plenum 5a integrated and with a bypass line 12 equipped, bypassing the intercooler 11 serves and hereinafter also as a second bypass line 12 referred to as.

This second bypass line 12 branches upstream of the intercooler 11 forming a third node 12a from the intake system 5 and discharges downstream of the intercooler 11 forming a fourth node 12b back into the intake system 5 , The second bypass line 12 is with a second shut-off element 12c equipped, which at the third node 12a is arranged and both the second bypass line 12 as well as the intercooler 11 - at least partially - can release and block.

In the intake system 5 is also an electrically driven compressor 8th provided between the compressor 7b the exhaust gas turbocharger 7 and the intercooler 11 arranged and with the compressor 7b the exhaust gas turbocharger 7 is connected in series. The electrically driven compressor 8th is as a switchable compressor 8th designed, which can be switched on and operated if necessary, for example, in the context of a cold start heat by compression in the pumped air enter and thus in the intake system 5 air present.

The electrically driven compressor 8th can be activated and operated before a - not shown - starting device is activated, ie as a preparatory measure preparatory to standstill crankshaft, and / or while the crankshaft is already forcibly set by means of starting device in rotation.

This is intended to heat the internal combustion engine 10 along with their operating fluids propelled, ie the warm-up phase can be shortened, whereby the fuel consumption can be reduced and the pollutant emissions can be reduced.

The electrically driven compressor 8th can also support the compressor 7b the exhaust gas turbocharger 7 be switched on to the fired cylinders 1 . 2 . 3 . 4 to supply sufficient charge air or to provide a requested charge pressure.

The electrically driven compressor 8th is with a bypass line 9 fitted. This first bypass line 9 branches downstream of the electrically driven compressor 8th forming a first node 9a from the intake system 5 from and opens between the electrically driven compressor 8th and the compressor 7b the exhaust gas turbocharger 7 forming a second node 9b back into the intake system 5 , This first bypass line 9 allows the heated air by means of the electrically driven compressor 8th To promote in a circle or in the intake system 5 to circulate.

In the present case branches the first bypass line 9 under the formation of the first node 9a from the second bypass line 12 so that the electrically driven compressor 8th warmed up, not in the intercooler 11 cooled air via first bypass line 9 promotes or returns to its suction side.

The first bypass line 9 is also with a shut-off element 9c equipped, wherein upstream of this first shut-off element 9c a sensor for metrological detection of the temperature of the via bypass line 9 funded air can be provided.

The first shut-off element 9c serves to release the first bypass line 9 and the setting of means of electrically driven compressor 8th recirculated air volume. The boost pressure in the intake system 5 downstream of the electrically driven compressor 8th as well as the cylinders 1 . 2 . 3 . 4 supplied amount of air can by using the drive line of the electrically driven compressor 8th and / or the degree of opening of the first shut-off element 9c be set.

The internal combustion engine 10 For the aftertreatment of the exhaust gas has several exhaust aftertreatment systems 14 that in the exhaust system 6 are arranged, namely an oxidation catalyst 14a , a particle filter 14b and an SCR catalyst 14c ,

Furthermore, the internal combustion engine 10 with an exhaust gas recirculation 13 equipped, which includes a return line downstream of the turbine 7a and downstream of the particulate filter 14b branches off from the entire exhaust line and upstream of the compressor 7b of the exhaust gas turbocharger 7 back into the intake system 5 empties. It is thus a low-pressure EGR.

LIST OF REFERENCE NUMBERS

1

first cylinder, outboard cylinder

2

second cylinder, internal cylinder, switchable cylinder

3

third cylinder, internal cylinder, switchable cylinder

4

fourth cylinder, outboard cylinder

5

intake system

5a

plenum

6

Abgasabführsystem

7

turbocharger

7a

Turbine of the exhaust gas turbocharger

7b

Compressor of the exhaust gas turbocharger

8th

electrically driven compressor

9

first bypass line

9a

first node

9b

second node

9c

first shut-off element

10

Internal combustion engine, four-cylinder in-line engine

11

Intercooler

12

second bypass line

12a

third node

12b

fourth node

12c

second shut-off element

13

Exhaust gas recirculation

14

aftertreatment system

14a

oxidation catalyst

14b

particulate Filter

14c

SCR catalyst

Claims (20)

Internal combustion engine (10) with at least one cylinder head comprising at least one cylinder (1, 2, 3, 4), in which - each cylinder (1, 2, 3, 4) has at least one inlet opening, to which a suction line for supplying air connected via intake system (5), - each cylinder (1, 2, 3, 4) has at least one outlet opening, to which an exhaust pipe for discharging the exhaust gases via Abgasabführsystem (6) adjoins, - at least one exhaust gas recirculation (13) is provided and - an electrically drivable compressor (8) in the intake system (5) is arranged, characterized in that a first bypass line (9) is provided downstream of the electrically driven compressor (8) to form a first node (9a) of the intake system ( 5) branches off and upstream of the electrically driven compressor (8) to form a second node (9b) opens into the intake system (5). Internal combustion engine (10) after Claim 1 , characterized in that the first bypass line (9) is equipped with a first shut-off element (9c). Internal combustion engine (10) after Claim 1 or 2 , characterized in that a charge air cooler (11) in the intake system (5) is arranged downstream of the electrically driven compressor (8). Internal combustion engine (10) after Claim 3 , characterized in that a second bypass line (12) is provided, which branches off upstream of the charge air cooler (11) to form a third node (12a) from the intake system (5) and downstream of the charge air cooler (11) opens into the intake system (5) to form a fourth node (12b). Internal combustion engine (10) after Claim 4 , characterized in that the second bypass line (12) is equipped with a second shut-off element (12c). Internal combustion engine (10) according to one of Claims 3 to 5 , characterized in that the first bypass line (9) branches off upstream of the charge air cooler (11) to form a first node (9a) from the intake system (5). Internal combustion engine (10) after Claim 4 or 5 , characterized in that the first bypass line (9) branches off from the second bypass line (12) to form a first node (9a). Internal combustion engine (10) according to one of the preceding claims, characterized in that at least one exhaust gas turbocharger (7) is provided which comprises a turbine (7a) arranged in the exhaust gas removal system (6) and a compressor (7b) arranged in the intake system (5). Internal combustion engine (10) after Claim 8 , characterized in that the electrically driven compressor (8) downstream of the compressor (7b) of the at least one exhaust gas turbocharger (7) in the intake system (5) is arranged. Internal combustion engine (10) after Claim 9 , characterized in that the first bypass line (9) between the electrically driven compressor (8) and the compressor (7b) of the at least one exhaust gas turbocharger (7) to form the second node (9b) in the intake system (5) opens. Internal combustion engine (10) according to one of Claims 3 to 10 , Characterized in that downstream of the charge air cooler (11) is a collecting container for the condensate in the intake system (5) is arranged. Internal combustion engine (10) according to one of Claims 3 to 11 , characterized in that the intercooler (11) is self-draining. Internal combustion engine (10) according to one of Claims 8 to 12 Characterized in that the electrically drivable compressor (8) is designed to be smaller than the compressor, (7b) of the at least one exhaust gas turbocharger (7). Internal combustion engine (10) according to one of the preceding claims, characterized in that only one exhaust gas turbocharger (7) is provided. Internal combustion engine (10) according to one of the preceding claims, characterized in that a sensor for measuring the temperature of the air in the intake system (5) is provided. A method for starting an internal combustion engine (10) according to any one of the preceding claims, characterized in that the electrically driven compressor (8) is operated in the context of a cold start to heat in the through the electrically driven compressor (8) conveyed air and thus in the air in the intake system (5). Method according to Claim 16 for operating an internal combustion engine (10) with crankshaft and starting device, characterized in that the electrically drivable compressor (8) is activated and operated before the starting device is activated to forcibly set the crankshaft in rotation. Method according to Claim 17 , characterized in that the electrically driven compressor (8) is further operated while the crankshaft is forcibly rotated by means of starting device. Method according to Claim 16 for operating an internal combustion engine (10) with crankshaft and starting device, characterized in that the electrically drivable compressor (8) is activated and operated, while the crankshaft is forcibly rotated by means of starting device. Method according to one of Claims 16 to 19 for operating an internal combustion engine (10), in which the first bypass line (9) is equipped with a first shut-off element (9c), characterized in that a boost pressure in the intake system (5) downstream of the electrically driven compressor (8) and the at least one Cylinder (1, 2, 3, 4) supplied amount of air can be adjusted using a drive line of the electrically driven compressor (8) and / or an opening degree of the first shut-off element (9c).

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