Rechargeable internal combustion engine, motor vehicle with such an engine and method for operating a rechargeable internal combustion engine

Abstract

A turbocharged internal combustion engine (30) comprising a spark-ignition combustion engine (20), a fresh gas line (18) with at least one compressor (4), an exhaust system (16) with at least one turbine (5), at least one catalyst (12) and at least one particulate filter (14), which are arranged downstream of the turbine (5), and a gas exchange line (38) with a first line section (1) which begins downstream of the turbine (5) and downstream of the catalyst (12) and upstream of the particulate filter (14) from the exhaust system (16) and branches at a junction point into a second line section (2) and a third line section (3), wherein the second line section (2) opens upstream of the compressor (4) and the third line section (3) opens downstream of the compressor (4) into the fresh gas line (18), wherein at the junction point of the gas exchange line (38) a a 3-way valve (10) is arranged, with which two of the line sections (1, 2,3) are fluidically connectable and the remaining pipe section is sealable.

Description

[0001] The invention relates to a rechargeable internal combustion engine with a spark-ignition combustion engine having the features according to claim 1. Furthermore, the invention relates to a motor vehicle with such a rechargeable internal combustion engine and to a method for operating a rechargeable internal combustion engine having the features of the independent claims.

[0002] For the operation of modern internal combustion engines, measures are taken to keep the emission of particles and pollutants low, while simultaneously offering the user a demanding performance profile. For example, one goal in the design of a specific internal combustion engine is to achieve the lowest possible fuel consumption in the combustion chamber in order to minimize the amount of exhaust gas emitted during operation.

[0003] In addition to exhaust gases, combustion in internal combustion engines can also produce soot particles. Particulate filters, particularly gasoline particulate filters in spark-ignition engines, are located in the exhaust system and capture these particles. The soot buildup in the particulate filter increases the exhaust back pressure, resulting in regular thermal oxidation to gaseous products to regenerate the filter. Regeneration requires a sufficiently high oxygen concentration and a sufficiently high temperature, typically above 550 °C, within the particulate filter.

[0004] For example, it is known from document DE 10 2009 046 559 A1 for the regeneration of a particulate filter to introduce compressed charge air via a gas line upstream of the particulate filter and downstream of a turbine in order to supply oxygen to the particulate filter for the combustion of the soot particles to CO2.

[0005] Application DE 10 2015 202 323 A1 reveals the use of a secondary air line of a spark-ignition turbocharged internal combustion engine for both the regeneration of a gasoline particulate filter and for reducing the engine's throttling. The secondary air line, which originates from the fresh air stream downstream of the compressor, connects to the exhaust stream upstream of the turbine.

[0006] Furthermore, document WO 2010 / 020 265 A1 proposes a multifunctional gas line. Exhaust gases are routed via a piping system and at least two valves into a heat exchanger or into the fresh gas line. This allows either exhaust gas recirculation or, using a heat exchanger, the temperature of an engine block to be controlled via the heat transfer from fresh gas or exhaust gas to a coolant.

[0007] In DE 10 2014 215 215 A1, methods and systems for reducing condensate accumulation on a charge air cooler (CAC) during cold ambient conditions are provided. A boost pressure control valve can be kept closed during a cold start of the engine, while a compressor recirculation valve is kept open to utilize compression heating and increased compressor recirculation to accelerate the warming of the CAC. The EGR supply is delayed until the CAC is sufficiently warm to reduce the tendency to condense.

[0008] The addition of multiple mechanisms and functions to the internal combustion engine, which redirect exhaust gas or fresh gas, results in a greater need for installation space. This consequence is disadvantageous insofar as minimum dimensioning requirements, such as cross-section and length, must be met.

[0009] The object of the present invention is to provide a rechargeable internal combustion engine with a small installation space.

[0010] This problem is solved according to the invention by a rechargeable internal combustion engine with the features according to claim 1. Advantageous embodiments of the invention are characterized in the dependent claims.

[0011] A turbocharged internal combustion engine according to the invention comprises a spark-ignition combustion engine, a fresh gas stream with at least one compressor, an exhaust system with at least one turbine, at least one catalyst and at least one particulate filter, which are arranged downstream of the turbine, and a gas exchange line with a first line section which begins downstream of the turbine and downstream of the catalyst and upstream of the particulate filter from the exhaust system and branches at a junction point into a second line section and into a third line section, wherein the second line section opens upstream of the compressor and the third line section opens downstream of the compressor into the fresh gas stream.

[0012] According to the invention, a 3-way valve is arranged at the branching point of the gas exchange line, with which two of the line sections can be fluidically connected and the remaining line section, more precisely the remaining of the line sections, can be sealed, particularly simultaneously.

[0013] According to the invention, several individual gas lines, each with at least one valve, are replaced by three line sections and a 3-way valve. This advantageously saves installation space and reduces the number of components required. These savings have a beneficial effect on the installation space freed up for other designs. In certain embodiments, the weight of the internal combustion engine can also be reduced. Another feature is the sealing, particularly the simultaneous sealing, of the unconnected line section against the fluidic connection between the two remaining line sections.

[0014] During operation, an internal combustion engine can develop a very high pressure differential between individual pipe sections. This pressure difference can lead to uncontrolled and unwanted fluidic connections. To control, and in particular regulate, the operation of the fluidic connection under high pressure differences, at least one one-way valve can be installed in at least one pipe section.

[0015] The 3-way valve used according to the invention can create fluidic connections via an actuating and closing unit, for example, with a rotating flap or a pivoting volume. In a group of embodiments, the 3-way valve can also utilize a rotatable volume for fluidic connection and variable throttling. A rotatable volume can have the advantage of providing a tighter seal, allowing the device to operate in a high pressure differential range without the need for 1-way valves. The 1-way valve can be any actuated valve, such as a ball valve or a butterfly valve. The advantage of installing at least one 1-way valve is that the pressure requirements for the 3-way valve, whose seal is designed for the pressure differentials of the internal combustion engine, are reduced.In a use according to the invention, a one-way valve, allowing both flow directions, for example a ball valve, can be fitted to the first pipe section. One-way valves for both flow directions or only one flow direction, for example a check valve, can be installed in the other two pipe sections.

[0016] The internal combustion engine can be a component of a vehicle, particularly a land vehicle. Preferably, the vehicle is a passenger car or a commercial vehicle, with a particulate filter located in the vehicle's underbody. In other words, the particulate filter is located away from the engine, i.e., not in the engine compartment, and especially not on the engine itself. The internal combustion engine is preferably part of the vehicle's drive system. In particular, it can be the sole source of power or part of a hybrid drive, for example, in combination with one or more electric motors. Preferably, it is a spark-ignition internal combustion engine, especially one with direct injection into the combustion chambers.

[0017] One of the advantages of arranging the particulate filter in the underbody is achieving the lowest possible exhaust backpressure for the combustion engine. Furthermore, more installation space is generally available for the particulate filter, allowing for a larger package compared to installation between the underbody and the combustion chamber, a more engine-close installation. By adapting to a larger installation space, a lower volume flow rate in the particulate filter can also be achieved. For a particulate filter located far from the engine, the invention enables the supply of the necessary oxygen concentration for its regeneration.

[0018] Related to the inventive concept is also a method for operating an internal combustion engine, in particular an internal combustion engine according to the invention. In the method according to the invention, two of the pipe sections of the gas exchange line are fluidically connected by means of the 3-way valve.

[0019] The inventive design advantageously allows a choice as to which of the connections should be made, since, for example, particle filter regeneration and the recirculation valve function can be carried out simultaneously or separately.

[0020] In advantageous embodiments, it is provided that a fluid flow through the gas exchange line is regulated by means of a variable flow cross-section, particularly in the gas exchange line.

[0021] A variable flow cross-section allows for control of the flow rates through the fluidic connections, thus extending the operating range of the individual connections. Exhaust gas recirculation, for example, can be continuously adjusted as a result. According to the invention, for the regeneration of the particulate filter, the first line section is fluidically connected to the third line section via the 3-way valve, while the second line section remains sealed. This step allows the oxygen concentration and / or temperature to be adjusted to the conditions required for particulate filter regeneration.

[0022] Sealing the fluidic connection against the second pipe section is advantageous in this context because the pressure gradient also drops towards the intake manifold, and thus, without sealing, the oxygen content in the particulate filter would increase only slightly.

[0023] This process step can preferably be initiated by an engine control unit determining the need for particulate filter regeneration via a sensor and / or a model. The need for regeneration is derived from the effects of the soot load in the particulate filter on the internal combustion engine's characteristics. This determination can be made directly via a sensor or indirectly via a simulation model, such as an observer-controller model. This allows the regeneration time to be advantageously adapted to the current internal combustion engine operation.

[0024] According to the invention, the temperature increase is supported by operating the internal combustion engine with at least one post-injection and / or at least one retarded ignition timing while compressed air is introduced upstream of the particulate filter. Thus, compared to operation without using the secondary air fluid connection for particulate filter regeneration, at least one injection time and / or at least one ignition timing is set to a later point in time. The changes to the combustion settings have the advantage that the exhaust gas temperature is raised to the temperature range required for particulate filter regeneration in otherwise cold operating situations, such as short trips. Furthermore, or alternatively, for exhaust gas recirculation, the first pipe section can be fluidically connected to the second pipe section via the 3-way valve, while the third pipe section remains sealed.

[0025] Exhaust gas recirculation can reduce the fuel consumption of a turbocharged internal combustion engine across a wide operating range. This effect can be further enhanced by additionally cooling the recirculated exhaust gas and / or the charge air. Alternatively, or in addition, a connection can be established between the compressor discharge side and the exhaust system or the compressor intake side. This connection reduces the compressor pressure. As a result, both the braking effect of the increasing back pressure and the occurrence of acoustic phenomena are reduced, preferably largely prevented. In this way, the function of a diverter valve can be advantageously implemented.In the associated embodiment of the method according to the invention, to discharge a compressor mass flow in a load change, either the second line section is connected to the third line section or the first line section is connected to the third line section, while the remaining line section is sealed.

[0026] Further advantages, advantageous embodiments, and developments of the invention are presented in the following description with reference to the figures. Specifically, it shows: Fig. 1 a schematic representation of the topology of a preferred embodiment of the rechargeable internal combustion engine according to the invention, and Fig. 2 a schematic illustration of an embodiment of the inventive method of possible fluid combinations.

[0027] Fig. Figure 1 is a schematic representation of the topology of a preferred embodiment of the turbocharged internal combustion engine 30 according to the invention. The turbocharged internal combustion engine 30 is the drive unit of a motor vehicle 40. It comprises a spark-ignition combustion engine 20, in particular a piston engine, shown here by way of example with four combustion chambers, specifically cylinders. Fresh gas 32 is supplied to the spark-ignition combustion engine 20 via a fresh gas line 18. Before entering the fresh gas line 18, the air must usually pass through a fresh air filter, which is not shown in this drawing. In the fresh gas line 18, the fresh air is compressed by a compressor 4. In the embodiment shown here, a throttle valve 26 and an intercooler 24 are also arranged downstream of the compressor 4.After the charge air cooler 24, the charge air is directed through an intake pipe 36 to the individual combustion chambers of the spark-ignition combustion engine 20.

[0028] Downstream of the combustion chambers, the turbocharged internal combustion engine 30 has an exhaust system 16: In the exhaust system 16, the exhaust gas 34 is combined via the exhaust manifold 38 and directed to a turbine 5. In this embodiment, the turbine 5 and the compressor 4 form a turbocharger group 8. That is, the turbine 5 drives the compressor 4 by expanding the exhaust gas 34. Downstream of the turbine 5, the exhaust system 16 contains a catalyst 12 and a particulate filter 14, in particular a gasoline particulate filter. Other exhaust gas treatment devices, such as catalysts in general and, in particular, three-way catalysts, storage catalysts, oxidation catalysts, reduction catalysts, and the like, which are present in typical turbocharged internal combustion engines 30, motor vehicles 40, and also in this embodiment, are not shown graphically. The particulate filter 14 can also be incorporated into further developments of the one described here. Fig. The embodiment shown in Figure 1 has one or more catalytic coatings. The particulate filter 14 is arranged in the underbody of the motor vehicle 40. The cleaned exhaust gas 34 is then discharged from the exhaust system 16 into the environment.

[0029] A gas exchange line 38 is installed between the exhaust gas line 16 and the fresh gas line 18. The first line section 1 begins on the exhaust gas line 16 downstream of the catalyst 12 and upstream of the particulate filter 14. In this configuration, the first line section 1 is equipped with an exhaust gas cooler 6. The exhaust gas cooler 6 is located upstream of a 3-way valve 10. Two further line sections branch off from the 3-way valve 10. The second line section 2 branches off from the 3-way valve 10 and terminates upstream of the compressor 4 in the fresh gas line 18. The third line section 3 branches off from the 3-way valve and terminates downstream of the compressor 4 in the fresh gas line 18. The gas exchange line thus consists of the first line section 1, the second line section 2, and the third line section 3.

[0030] The third line section 3 comprises in the Fig. In the embodiment shown in Figure 1, a 1-way valve 28 is used. The 1-way valve 28 can seal the high-pressure area downstream of the compressor 4 against the third line section 3 and is, in particular, controllable.

[0031] The turbocharged internal combustion engine 30 has a control unit 50, for example, an engine control unit. The control unit 50 is designed such that individual operating parameters of the turbocharged internal combustion engine 30 can be controlled or regulated. For this purpose, the control unit 50 is operatively connected to various actuators for manipulated variables to change operating parameters and / or to various sensors for measuring operating parameters. Fig. Figure 1 shows the functional connections related to the invention. According to the invention, the control unit 50 is designed such that it can control or regulate the fuel-air ratio in the combustion chambers and / or one or more ignition angles and / or one or more injection timings of the spark-ignition internal combustion engine 20. According to the invention, the control unit 50, particularly in the embodiment shown, has connections for control and information retrieval with the particulate filter 14 and with the one-way valve 28, for example, connections for transmitting data on the pressure values ​​in the particulate filter 14 or connections for controlling and querying the setting of the one-way valve 28. With these control and information connections, the control unit can query the temperature and pressure conditions on both sides of the particulate filter and the one-way valve and check and control the setting of the one-way valve 28.The control unit 50 has an actuator connection to the 3-way valve 10. The connections to the control unit 50 can be mechanical, for example levers, digital, for example via fiber optic cables or copper wire, or wireless, for example radio.

[0032] Fig. Figure 2 shows a flowchart of a preferred embodiment of the inventive method for operating the spark-ignition internal combustion engine 30. The inventive method enables the regeneration of the particulate filter 14, the low-pressure exhaust gas recirculation, and the discharge of the compressor mass flow during load changes by adjusting the 3-way valve 10.

[0033] In step 42, the rechargeable internal combustion engine 30 according to the invention is charged by means of the compressor 4. In this step, there is no fluidic connection between the line sections 1, 2 or 3.

[0034] In step 44, operating parameters and / or measured values ​​from the turbocharged internal combustion engine 30 are evaluated in the control unit 50. Measured values ​​can include, for example, one or more of the following: the exhaust back pressure before and after the particulate filter, the engine speed, and the exhaust gas temperature. Measured values ​​can be determined and evaluated for one or more of these measured values. Operating parameters include, for example, the injection angle, the injection quantity, and the ignition timing.

[0035] Depending on the evaluation in step 44, individual steps or several steps are now executed in parallel.

[0036] If the data evaluation of the operating parameters and / or measured variables in step 44 indicates an operating condition in which exhaust gas recirculation can be advantageous, for example, a high-load range in which exhaust gas recirculation can reduce fuel consumption, then step 60 follows and the control unit sends a control signal to the 3-way valve 10, which establishes a fluidic connection between the first line section 1 and the second line section 2. According to the invention, this connection can be configured with a throttled flow rate. Through this connection, exhaust gas enters the fresh gas stream, thus reducing the proportion of combustible substances in the combustion chamber mixture. In an exemplary embodiment according to the invention, the recirculated exhaust gas is, as shown in Fig. 1 shown once before entering the fresh gas line and once cooled in the fresh gas line.

[0037] If the data evaluation of the measured exhaust gas system data in step 44 indicates an operating condition in which regeneration of the particulate filter 14 is necessary, for example, an exhaust back pressure exceeding the limit value upstream of the particulate filter 14 and a lower pressure downstream of the particulate filter 14, then step 52 follows and the control unit retards one or more ignition timings and / or one or more injection timings. Once this has occurred, step 48 follows and the control unit 50 sends a control signal to the 3-way valve 10 and the 1-way valve 28. The 3-way valve 10 establishes a fluidic connection between the first line section 1 and the third line section 3, and the 1-way valve 28 opens. Oxygen-rich charged fresh gas 32 is fed into the exhaust stream 16 immediately before the particulate filter 14, thereby increasing the oxygen content in the particulate filter 14 to the value required for regeneration.These two steps increase the oxygen content and raise the temperature in the exhaust system16 at the particulate filter14 to 500 to 1100 degrees Celsius.

[0038] In this advantageous way, the conditions for the thermal regeneration of the particle filter 14 are created.

[0039] If the data evaluation in step 44 indicates a load change, particularly from traction to deceleration, for example due to increasing pressure downstream of compressor 4 and a decreasing throttle opening, then in step 46 the control unit 50 queries whether regeneration of the particulate filter is also necessary. If this is determined to be necessary, step 48 is carried out in parallel with step 52. This advantageously reduces the pressure downstream of compressor 4.

[0040] If no need for regeneration is detected in step 46, step 54 follows, and the control unit 50 sends a control signal to the 3-way valve 10 and the 1-way valve 28. The 3-way valve 10 establishes a fluidic connection between the second line section 2 and the third line section 3, and the 1-way valve 28 opens. This fluidic connection reduces the pressure downstream of the compressor 4.

[0041] By releasing the pressure, the occurrence of acoustic phenomena due to the pressure build-up and the deceleration of the fresh gas 32 of the compressor 2 is advantageously prevented.

[0042] In the preferred embodiment of the method, the particle filter 14 can be regenerated as required directly after step 44 with step 52 or in parallel with step 48, in order to both reduce the pressure downstream of the compressor 4 and regenerate the particle filter 14. Reference symbol list 1 first section of the line 2 second line section 3 third line section 4 compressors 5 Turbine 6 exhaust gas coolers 8 exhaust gas turbochargers 10 3-way valve 12 Catalyst 14 particulate filters 16 Exhaust system 18 Fresh gas line 20 internal combustion engine 24 Intercoolers 26 Throttle valve 28 1-way valve 30 Internal combustion engine 32 Fresh gas 34 Exhaust gas 36 Intake manifold 38 Gas exchange line 40 motor vehicle 50 control unit

Claims

A turbocharged internal combustion engine (30) comprising a spark-ignition combustion engine (20), a fresh gas line (18) with at least one compressor (4), an exhaust system (16) with at least one turbine (5), at least one catalyst (12) and at least one particulate filter (14), which are arranged downstream of the turbine (5), and a gas exchange line (38) with a first line section (1) which begins downstream of the turbine (5) and downstream of the catalyst (12) and upstream of the particulate filter (14) from the exhaust system (16) and branches at a junction point into a second line section (2) and a third line section (3), wherein the second line section (2) opens upstream of the compressor (4) and the third line section (3) opens downstream of the compressor (4) into the fresh gas line (18), wherein at the junction point of the gas exchange line (38) a a 3-way valve (10) is arranged, with which two of the line sections (1, 2,3) are fluidically connectable and the remaining pipe section is sealable. Rechargeable internal combustion engine (30) according to claim 1, wherein at least one 1-way valve (28) is arranged in at least one line section. Motor vehicle comprising a rechargeable internal combustion engine (30) according to one of the preceding claims, wherein the particulate filter (14) is arranged on an underbody of the motor vehicle (40). Method for operating a turbocharged internal combustion engine (30) according to claim 1 or 2, in which the turbocharged internal combustion engine (30) is charged by means of the compressor (4), wherein two of the line sections of the gas exchange line (38) are fluidically connected by means of the 3-way valve (10), wherein for the regeneration of the particulate filter (14) the first line section (1) is fluidically connected to the third line section (3) via the 3-way valve (10), while the second line section (2) is sealed, and wherein the internal combustion engine (30) is operated with at least one post-injection and / or at least one retarded ignition angle. Method according to claim 4, wherein a fluid flow through the gas exchange line (38) is controlled by means of a variable flow cross-section. Method according to claim 4, wherein an engine control unit (50) determines the need for regeneration of the particulate filter (14) via a sensor and / or a model. Method for operating a rechargeable internal combustion engine (30) according to claim 1 or 2, in which the rechargeable internal combustion engine (30) is charged by means of the compressor (4), wherein two of the line sections (1, 2, 3) of the gas exchange line (38) are fluidically connected by means of the 3-way valve (10), wherein for exhaust gas recirculation the first line section (1) is fluidically connected to the second line section (2) via the 3-way valve (10), while the third line section (3) is sealed. Method for operating a rechargeable internal combustion engine (30) according to claim 1 or 2, in which the rechargeable internal combustion engine (30) is charged by means of the compressor (4), wherein two of the line sections (1, 2, 3) of the gas exchange line (38) are fluidically connected by means of the 3-way valve (10), wherein, in order to discharge a compressor mass flow in a load change, either the second line section (2) is fluidly connected to the third line section (3) or the first line section (1) is fluidly connected to the third line section (3), while the remaining line section (2, 3) is sealed.

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