DE102017200739A1 - Charged internal combustion engine with exhaust aftertreatment and method for operating such an internal combustion engine - Google Patents

Charged internal combustion engine with exhaust aftertreatment and method for operating such an internal combustion engine

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Publication number
DE102017200739A1
DE102017200739A1 DE102017200739.7A DE102017200739A DE102017200739A1 DE 102017200739 A1 DE102017200739 A1 DE 102017200739A1 DE 102017200739 A DE102017200739 A DE 102017200739A DE 102017200739 A1 DE102017200739 A1 DE 102017200739A1
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DE
Germany
Prior art keywords
exhaust
valve
valve lift
internal combustion
combustion engine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
DE102017200739.7A
Other languages
German (de)
Inventor
Werner Willems
Claudia Herudek
Wilbert Hemink
Christian Hans
Rob Stalman
Claudia Conée
Daniel Mosbeux
Jos van de Venne
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ford Global Technologies LLC
Original Assignee
Ford Global Technologies LLC
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Application filed by Ford Global Technologies LLC filed Critical Ford Global Technologies LLC
Priority to DE102017200739.7A priority Critical patent/DE102017200739A1/en
Publication of DE102017200739A1 publication Critical patent/DE102017200739A1/en
Pending legal-status Critical Current

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0273Multiple actuations of a valve within an engine cycle
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0242Variable control of the exhaust valves only
    • F02D13/0246Variable control of the exhaust valves only changing valve lift or valve lift and timing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/021Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/024Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
    • F02D41/0245Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus by increasing temperature of the exhaust gas leaving the engine
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002Controlling intake air
    • F02D2041/001Controlling intake air for engines with variable valve actuation
    • Y02T10/18
    • Y02T10/26

Abstract

A supercharged internal combustion engine having at least one cylinder, wherein each cylinder has at least two exhaust ports for discharging the exhaust gases via Abgasabführsystem, - the cylinder-associated openings are each equipped with a valve train comprising a valve which, using an actuator along a longitudinal axis between a valve closing position and a Valve-open position under full control of a maximum valve lift Δh is movable to release the opening in the context of a charge exchange during an opening period .DELTA.t or obstruct the valvetrain of at least one outlet opening is at least partially variable in such a way that the control time at which the associated exhaust valve is opened It is to be provided an internal combustion engine, in which the temperature in the Abgasabführsystem can be increased quickly and less quickly if necessary. This is achieved with a Brennkraf tmaschine, which is characterized in that the valve train of at least one outlet opening is at least partially variable in the way that the associated exhaust valve is actuated in such a way that this exhaust valve performs an additional valve lift .DELTA.h before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve has completed the maximum valve lift Δh as part of the charge cycle.

Description

  • The invention relates to a supercharged internal combustion engine having at least one cylinder head with at least one cylinder in which
    • each cylinder has at least one inlet opening for supplying combustion air via the intake system and at least two outlet openings for discharging the exhaust gases via the exhaust removal system and has a piston which is movable along a piston longitudinal axis between a bottom dead center and a top dead center,
    • the cylinder-associated openings are each provided with a valvetrain comprising a valve which is movable by use of an actuator along a longitudinal axis between a valve closed position and a valve open position, carrying out a maximum valve lift Δh max, exhaust , around the opening during a charge cycle during an opening period To release or block Δt exhaust ,
    • - The valvetrain of at least one outlet opening is at least partially variable in the way that the control time at which the associated outlet valve is opened, is displaced to early, and
    • - At least one exhaust aftertreatment system is provided in the Abgasabführsystem.
  • Furthermore, the invention relates to a method for operating such an internal combustion engine.
  • An internal combustion engine of the type mentioned is used as a drive for motor vehicles. In the context of the present invention, the term internal combustion engine includes gasoline engines, diesel engines, but also hybrid internal combustion engines, which use a hybrid combustion process, and hybrid drives, which in addition to the internal combustion engine comprise an electric motor which can be electrically connected to the internal combustion engine, which receives power from the internal combustion engine or as switchable auxiliary drive additionally delivers power.
  • Internal combustion engines have a cylinder block and at least one cylinder head, which are connected to form at least one cylinder.
  • The cylinder block has a corresponding number of cylinder tubes for receiving the piston. The piston of each cylinder of an internal combustion engine is guided along the cylinder longitudinal axis axially movable in a cylinder tube and limited together with the cylinder tube and the cylinder head, the combustion chamber of a cylinder. The piston head forms a part of the combustion chamber inner wall and seals together with the piston rings the combustion chamber against the cylinder block or the crankcase, so that no combustion gases or combustion air enter the crankcase and no oil enters the combustion chamber.
  • The pistons serve to transfer the gas forces generated by the combustion to the crankshaft. For this purpose, each piston is articulated by means of a piston pin with a connecting rod, which in turn is movably mounted on the crankshaft.
  • The crankshaft mounted in the crankcase in at least two crankshaft bearings receives the connecting rod forces, which are composed of the gas forces due to the fuel combustion in the combustion chamber and the mass forces due to the nonuniform motion of the engine parts. In this case, the oscillating stroke movement of the pistons is transformed between a lower and upper dead center into a rotating rotational movement of the crankshaft. The crankshaft transmits the torque to the drive train. Part of the energy transferred to the crankshaft is used to drive auxiliary equipment such as the oil pump and the alternator or serves to drive the camshaft and thus actuate the valve trains.
  • Regularly, the upper crankcase half is formed by the cylinder block. The crankcase is supplemented by the lower half of the crankcase, which can be mounted on the upper crankcase half and serves as an oil sump.
  • The cylinder head is usually used to hold the valve train. To control the charge cycle, an internal combustion engine requires controls and actuators to operate the controls. As part of the change of charge of a cylinder, the expulsion of the combustion gases via at least one outlet opening and the filling of the combustion chamber with combustion air via at least one inlet opening takes place. To control the charge cycle, four-stroke engines use almost exclusively globe valves as control members, which perform an oscillating stroke movement along their longitudinal axis during operation of the internal combustion engine and in this way release and close the inlet opening or outlet opening. The required for the movement of a valve actuator including the valve itself is referred to as a valve train.
  • It is the task of the valve drive to release the at least one inlet opening and / or outlet opening of a cylinder in good time close, with a quick release of the largest possible flow cross sections is sought in order to keep the throttle losses in the incoming and outflowing gas flows low and to ensure the best possible filling of the cylinder and a complete discharge of the exhaust gases. Therefore, according to the prior art, a cylinder is often and increasingly equipped with two or more inlet openings or outlet openings.
  • The internal combustion engine, which is the subject of the present invention, also has at least one inlet opening and at least two outlet openings.
  • The intake pipes leading to the intake ports and the exhaust pipes connecting to the exhaust ports are at least partially integrated in the cylinder head in the prior art.
  • Downstream of the outlet openings, the exhaust gases are then fed to an exhaust gas aftertreatment and optionally to a turbine, for example the turbine of an exhaust gas turbocharger. The internal combustion engine, which is the subject of the present invention, has at least one exhaust aftertreatment system.
  • Namely, in the development of internal combustion engines, efforts are constantly being made to reduce pollutant emissions in order to be able to comply with future limit values for pollutant emissions.
  • In the prior art, therefore, internal combustion engines are regularly equipped with various exhaust aftertreatment systems to reduce pollutant emissions. Although, without additional measures during the expansion and expulsion of cylinder filling at a sufficiently high temperature level and the presence of sufficiently large amounts of oxygen oxidation of the unburned hydrocarbons and carbon monoxide instead. However, these reactions come to a halt quickly due to the rapidly decreasing exhaust gas temperature downstream and consequently rapidly decreasing reaction rate.
  • For these reasons, the prior art gasoline engines use catalytic reactors which, using catalytic materials which increase the speed of certain reactions, ensure oxidation of the hydrocarbons and carbon monoxide even at low temperatures. If, in addition, nitrogen oxides are to be reduced, this can be achieved by using a three-way catalytic converter which, however, requires a narrow-flow stoichiometric operation (λ≈1) of the gasoline engine. In this case, the nitrogen oxides are reduced by means of the existing unoxidized exhaust gas components, namely the carbon monoxide and the unburned hydrocarbons, wherein at the same time these exhaust gas components are oxidized.
  • In internal combustion engines, which are operated with an excess of air, so for example in lean-burn gasoline engines, but in particular direct-injection diesel engines and direct injection gasoline engines, the nitrogen oxides located in the exhaust gas, in principle, d. H. due to the lack of reducing agents, can not be reduced.
  • For oxidation of the unburned hydrocarbons and of carbon monoxide, an oxidation catalyst is then provided in the exhaust gas removal system. For a noticeable, d. H. sufficient conversion is a minimum temperature - the so-called light-off temperature - required, which may for example be between 120 ° C to 250 ° C.
  • To reduce the nitrogen oxides, it is possible to use selective catalysts, so-called SCR catalysts, in which reducing agent is introduced into the exhaust gas in a targeted manner in order to selectively reduce the nitrogen oxides. As a reducing agent, not only ammonia and urea but also unburned hydrocarbons are used. The latter is also referred to as HC enrichment, wherein the unburned hydrocarbons are introduced directly into the Abgasabführsystem or else by internal engine measures, for example, by a post injection of additional fuel into the combustion chamber after the actual combustion supplied. In this case, the nacheingespritzte fuel should not be ignited in the combustion chamber by the still running main combustion or by the high combustion gas temperatures even after completion of the main combustion, but are introduced into the exhaust tract during the charge exchange.
  • It must be taken into account that the use of fuel as a reducing agent inherently increases the fuel consumption of the internal combustion engine, for which reason SCR catalysts are increasingly used to reduce nitrogen oxides, in which ammonia or urea is provided as reducing agent.
  • Due to the toxicity, ammonia is often not stored in its purest form in motor vehicles and provided as a reducing agent. Rather, urea is regularly used as a starting material for the production of ammonia. Because urea can under energy input in the context of a thermolytic reaction in ammonia and isocyanic acid be split. The isocyanic acid can then be hydrolyzed in the presence of water to ammonia and carbon dioxide.
  • In principle, the nitrogen oxide emissions can also be reduced with a so-called nitrogen oxide storage catalyst (LNT). The nitrogen oxides are first absorbed during a lean operation of the internal combustion engine in the catalyst, d. H. collected and stored, in order then to be reduced during a regeneration phase, for example by means of a substoichiometric operation (λ <1) of the internal combustion engine with lack of oxygen, wherein the unburned hydrocarbons serve as a reducing agent. Further internal engine options for enriching the exhaust gas with reducing agent, in particular unburned hydrocarbons, provides the exhaust gas recirculation and diesel engines throttling in the intake system. As already stated, an enrichment of the exhaust gas with unburned hydrocarbons can also be realized by means of post-injection of fuel. In-engine measures can be dispensed with if the reducing agent is introduced directly into the Abgasabführsystem, for example by injecting additional fuel. During the regeneration phase, the nitrogen oxides are released and converted essentially into nitrogen dioxide, carbon dioxide and water.
  • The frequency of the regeneration phases is determined by the total emission of nitrogen oxides and the storage capacity of the LNT. The temperature of the storage catalyst should preferably be in a temperature window between 200 ° C and 450 ° C, so that on the one hand a rapid reduction is ensured and on the other hand there is no desorption without conversion of the re-released nitrogen oxides.
  • One difficulty with the use of the LNT results from the sulfur contained in the exhaust, which is also absorbed in the LNT and must be removed regularly in a so-called desulfurization. For this purpose, the LNT must be heated to high temperatures, usually between 600 ° C and 700 ° C, and supplied with a reducing agent.
  • To minimize the emission of soot particles so-called regenerative particulate filters are used in the prior art, which filter out and store the soot particles from the exhaust gas, these soot particles are intermittently burned in the regeneration of the filter. For this purpose, oxygen or an excess of air in the exhaust gas is required to oxidize the soot in the filter, which can be achieved for example by a superstoichiometric operation (λ> 1) of the internal combustion engine.
  • The high temperatures of about 550 ° C for regeneration of the particulate filter in the absence of catalytic support are achieved in operation only at high loads and high speeds. Therefore, additional measures must be used to ensure regeneration of the filter under all operating conditions.
  • It can be seen from the above explanations that the different exhaust aftertreatment systems invariably require a certain operating temperature for the conversion of the pollutants, namely regularly a high or very high temperature. This requirement of exhaust gas aftertreatment to the temperature in the exhaust gas removal system is fundamentally, but especially in the warm-up phase or after a cold start, a problem or a challenge. Measures must be taken with which the different exhaust aftertreatment systems can heat up quickly or heat up.
  • A concept of the prior art for rapidly heating the Abgasabführsystems or an exhaust aftertreatment system provides an early or earlier opening of the cylinder outlet during the expansion, wherein the hot exhaust pressure driven escapes into the Abgasabführsystem escapes, optionally together with a portion of the introduced fuel, the then not burned in the cylinder, but in the Abgasabführsystem and thereby enters heat into the Abgasabführsystem. The chemically bound energy in the fuel is used here less than in the piston introduced work, but rather in the form of heat. The heat contributes to the rapid heating of the exhaust-gas removal system or of an exhaust-gas aftertreatment system arranged in the exhaust-gas removal system.
  • The above-described approach to opening the cylinder outlet early requires the provision of at least one exhaust port of the cylinder with an at least partially variable valvetrain which allows the opening time to be shifted early, i. H. allows early opening of the exhaust valve.
  • In the case of the internal combustion engine which is the subject of the present invention, the valve drive of at least one cylinder-related outlet opening is at least partially variable in such a way that the control time at which the associated outlet valve is opened, ie. H. the opening time, is displaced to early.
  • To when heating a arranged in Abgasabführsystem To be able to proceed more flexibly exhaust gas aftertreatment system, in particular to be able to heat up quickly and less, additional measures are required.
  • In view of the foregoing, it is an object of the present invention to provide a supercharged internal combustion engine according to the preamble of claim 1, wherein the temperature in the exhaust evacuation system can be increased rapidly and less rapidly as needed.
  • A further sub-task of the present invention is to show a method for operating such an internal combustion engine.
  • The first object is achieved by a supercharged internal combustion engine having at least one cylinder head with at least one cylinder in which
    • each cylinder has at least one inlet opening for supplying combustion air via the intake system and at least two outlet openings for discharging the exhaust gases via the exhaust removal system and has a piston which is movable along a piston longitudinal axis between a bottom dead center and a top dead center,
    • the cylinder-associated openings are each provided with a valvetrain comprising a valve which is movable by use of an actuator along a longitudinal axis between a valve closed position and a valve open position, carrying out a maximum valve lift Δh max, exhaust , around the opening during a charge cycle during an opening period To release or block Δt exhaust ,
    • - The valvetrain of at least one outlet opening is at least partially variable in the way that the control time at which the associated outlet valve is opened, is displaced to early, and
    • - At least one exhaust aftertreatment system is provided in the Abgasabführsystem, and which is characterized in that
    • - The valvetrain of at least one outlet opening is at least partially variable in the way that the associated exhaust valve is actuated in such a way that this exhaust valve performs an additional valve lift Δh add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve in the context of the charge change the maximum valve lift Δh max, exhaust has performed.
  • According to the invention, the outlet valve of at least one cylinder-related outlet opening can perform at least two valve lifts, wherein the actual, larger valve lift .DELTA.h max, exhaust , which serves primarily the charge exchange, an additional smaller valve lift .DELTA.h add, exhaust follows.
  • If an exhaust valve is opened again during the intake cycle of the charge cycle, during which the piston moves downwards, before the piston reaches bottom dead center, exhaust gas already exhausted into the exhaust gas removal system is sucked back in, ie. H. in the context of an internal exhaust gas recirculation via approved outlet opening fed back into the cylinder.
  • Through this internal exhaust gas recirculation of the fresh cylinder charge combustion gases are added. The exhaust gas component at the fresh cylinder charge increases. Due to the admixed exhaust gas, the ignition delay increases and the burning speed is reduced. As a result, while the peak temperature of the combustion process is lowered, thereby reducing the nitrogen oxide raw emissions. However, the time-averaged exhaust gas temperature increases due to the internal exhaust gas recirculation. At the same time, the gas flow rate through the internal combustion engine, d. H. the absolute amount of gas delivered by the cylinders and thus also the absolute amount of exhaust gas.
  • The multiple opening of an exhaust valve of a cylinder-associated exhaust port for internal recycling of hot exhaust gases results in a lower exhaust flow of higher temperature.
  • Like the premature opening of the cylinder outlet during expansion, multiple opening of a cylinder-associated exhaust valve may also be used to introduce heat into the exhaust system. In this case, the heating of the Abgasabführsystems or arranged in Abgasabführsystem exhaust aftertreatment system but moderate, d. H. less quickly than the premature opening of the cylinder outlet.
  • The exhaust gas temperature can be influenced by the opening duration and the height or size of the additional valve lift .DELTA.h add, exhaust and the time when the exhaust valve is opened again.
  • With the procedure according to the invention in which the outlet valve of at least one outlet opening performs at least one additional valve lift, not only can an exhaust aftertreatment system be heated or heated, but if desired also a hotter and thus more energy-rich or enthalpy-rich exhaust gas available to a turbine optionally provided in the exhaust-gas removal system be put.
  • The internal combustion engine according to the invention thus achieves the first object underlying the invention, namely to provide a supercharged internal combustion engine according to the preamble of claim 1, in which the temperature in the exhaust gas removal system can be increased quickly and less quickly if required.
  • According to the invention, a charge is provided, preferably an exhaust turbocharger.
  • 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.
  • Since the exhaust gases of the various internal combustion engines - albeit in different concentrations - both unburned hydrocarbons, carbon monoxide, nitrogen oxides and soot particles contain regularly combined exhaust aftertreatment systems are used, comprising one or more of the described catalysts, reactors and / or filters.
  • Further advantageous embodiments of the internal combustion engine according to the invention are discussed in connection with the subclaims.
  • Advantageous embodiments of the supercharged internal combustion engine, in which the valve train of at least two outlet openings is at least partially variable in the way that the control time to which the associated outlet valve is opened, is displaced to early.
  • If two or more cylinder-related outlet openings are used, the usable or used flow cross-section per cylinder increases considerably, which is why more combustion gases or more fuel particles enter the exhaust-gas removal system at early opening. The effect aimed at or achieved with the early opening of the cylinder outlet, namely to introduce heat into the exhaust gas removal system, is correspondingly clearer.
  • For this reason, embodiments of the supercharged internal combustion engine in which the valve train of at least two exhaust ports is at least partially variable in such a way that the associated exhaust valve is actuated in such a way that this exhaust valve performs an additional valve lift .DELTA.h add, exhaust before the advantageous Piston in the context of the charge change reaches the bottom dead center and after the exhaust valve in the context of the charge change the maximum valve lift Δh max, exhaust has performed.
  • Embodiments of the supercharged internal combustion engine in which the valve train of at least two outlet openings is at least partially variable in the manner that is advantageous are advantageous
    • - The control time to which the associated exhaust valve is opened, is displaced to early, and
    • - The associated exhaust valve is actuated in such a way that this exhaust valve performs an additional valve lift Δh add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve in the context of the charge change the maximum valve lift .DELTA.h max, exhaust has performed.
  • In the present case, the valvetrain and the like outlet opening both capabilities, both the ability to open earlier the associated exhaust valve during the change of charge, as well as the ability to open the associated exhaust valve several times, in particular a second time after the gas exchange. This applies to at least two valve trains or outlet openings per cylinder.
  • Embodiments of the supercharged internal combustion engine in which the additional valve lift Δh add, exhaust is less than one third of the maximum valve lift Δh max, exhaust are advantageous.
  • Embodiments of the supercharged internal combustion engine in which the additional valve lift Δh add, exhaust is less than one quarter of the maximum valve lift Δh max, exhaust are also advantageous.
  • The amount of the additional valve lift is always to be matched with the crank angle mark, to which the additional valve lift is performed. However, a large number of other parameters can be taken into consideration, for example the piston shape, the shape of the combustion chamber roof, but in particular the compression ratio ε of the cylinder or of the internal combustion engine.
  • Embodiments of the supercharged internal combustion engine in which the additional valve lift is less than 3 mm are advantageous.
  • Embodiments of the supercharged internal combustion engine in which the additional valve lift is less than 2 mm are advantageous.
  • The details of the above embodiments for the additional valve lift are exemplary only and are intended to illustrate the ratio to the maximum valve lift, which may easily be 8mm to 12mm.
  • Embodiments of the supercharged internal combustion engine in which each cylinder has two outlet openings for discharging the exhaust gases via the exhaust gas removal system are advantageous.
  • If two outlet openings per cylinder are used or provided, the flow cross-section per cylinder used in discharging the exhaust gases increases, which is why the throttling losses in the exiting exhaust gas flows can be reduced.
  • In this context, embodiments of the supercharged internal combustion engine in which the valve drive of each outlet opening is at least partially variable in the manner that is advantageous are advantageous
    • - The control time to which the associated exhaust valve is opened, is displaced to early, and
    • - The associated exhaust valve is actuated in such a way that this exhaust valve performs an additional valve lift Δh add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve in the context of the charge change the maximum valve lift .DELTA.h max, exhaust has performed.
  • In the present case, the valve trains of the two cylinder-related exhaust ports each have both capabilities, namely the ability to open earlier the associated exhaust valve during the change of charge, as well as the ability to open the associated exhaust valve several times, in particular a second time after the gas exchange.
  • In supercharged internal combustion engines, in which each cylinder has two outlet openings for discharging the exhaust gases via Abgasabführsystem, embodiments may also be advantageous, which are characterized in that
    • the valvetrain of a first outlet opening is at least partially variable in such a way that the control time at which the associated outlet valve is opened is displaceable early, and
    • the valvetrain of a second outlet opening is at least partially variable in that the associated outlet valve is actuatable in such a way that this outlet valve performs an additional valve lift .DELTA.h add exhaust before the piston reaches bottom dead center during the charge cycle and after the exhaust valve in the context of the charge change the maximum valve lift Δh max, exhaust has performed.
  • In the present case, the two capabilities, namely the ability to open the associated exhaust valve earlier during the charge cycle, and the ability to repeatedly open the associated exhaust valve, in particular a second time after the charge cycle, are distributed to the two valve trains of the two cylinder-related exhaust ports Each valve train is assigned an ability or is.
  • The valvetrain of a first exhaust port has only the ability to earlier open the associated exhaust valve during the charge cycle, i. H. to move the opening time to early.
  • On the other hand, the valve drive of a second outlet opening has the ability to open the associated outlet valve several times, in particular once more after the charge change.
  • Embodiments of the supercharged internal combustion engine in which an oxidation catalytic converter is provided in the exhaust gas removal system are advantageous.
  • Embodiments of the supercharged internal combustion engine in which a particle filter is provided in the exhaust gas removal system in order to minimize soot emissions are advantageous.
  • Embodiments of the supercharged internal combustion engine in which a nitrogen oxide storage catalytic converter is provided in the exhaust gas removal system are advantageous for reducing the nitrogen oxides.
  • Embodiments of the supercharged internal combustion engine in which a selective catalyst, i. E. H. a so-called SCR catalyst is provided in the exhaust gas removal system.
  • Embodiments in which the supercharged internal combustion engine is self-igniting, for example a diesel engine, are advantageous.
  • The second sub-task underlying the invention, namely to show a method for operating a supercharged internal combustion engine according to a previously described type, is achieved by a method in which the temperature in the exhaust gas discharge system is increased by
    • - the outlet valve of at least one outlet opening is opened sooner, or
    • the outlet valve of at least one outlet opening is actuated in such a way that this outlet valve performs an additional valve lift .DELTA.h add exhaust before the piston reaches the bottom dead center during the charge cycle and after the exhaust valve under full control performs the maximum valve lift .DELTA.h max, exhaust was pressed.
  • The comments made in connection with the internal combustion engine according to the invention also apply to the inventive method.
  • Embodiments of the method are advantageous in which the temperature in the exhaust-gas removal system is increased by
    • - the outlet valve of at least one outlet opening is opened earlier if a rapid increase in temperature is required, or
    • the outlet valve of at least one outlet opening is actuated in such a way that this outlet valve performs an additional valve lift .DELTA.h add exhaust before the piston reaches the bottom dead center during the charge cycle and after the exhaust valve under full control performs the maximum valve lift .DELTA.h max, exhaust was actuated if a moderate less rapid increase in temperature is required.
  • For operating a supercharged internal combustion engine, in which each cylinder has two outlet openings for discharging the exhaust gases via the exhaust gas removal system, process variants in which the temperature in the exhaust gas removal system is increased can be advantageous in that
    • - the outlet valves of both outlet openings are opened earlier, or
    • - The exhaust valves of both exhaust ports are operated in such a way that each exhaust valve performs an additional valve lift .DELTA.h add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve in the context of the charge cycle under full control the maximum valve lift .DELTA.h max, exhaust was pressed.
  • For operating a supercharged internal combustion engine in which each cylinder has two outlet openings for discharging the exhaust gases via Abgasabführsystem, also variants of the method may be advantageous in which the temperature in the Abgasabführsystem is increased by
    • - the outlet valve of a first outlet opening is opened earlier, or
    • the outlet valve of a second outlet opening is actuated in such a way that this outlet valve performs an additional valve lift .DELTA.h add exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve under full control performs the maximum valve lift .DELTA.h max, exhaust was pressed.
  • Advantageous embodiments of the method in which the additional valve lift .DELTA.h add, exhaust the exhaust valve is performed up to 80 ° CA before bottom dead center.
  • Advantageous embodiments of the method in which the additional valve lift .DELTA.h add, exhaust the exhaust valve is performed up to 60 ° CA before bottom dead center.
  • The closer the additional valve lift is performed at bottom dead center, the less exhaust gas is recirculated internally. The crank angle mark at which the additional valve lift is performed is to be matched with the amount of additional valve lift.
  • Embodiments of the method are advantageous in which the exhaust valve of the at least one outlet opening is again returned to the closed position after completion of the maximum valve lift Δh max, exhaust before the exhaust valve is opened again for the purpose of carrying out the additional valve lift Δh add, exhaust .
  • Embodiments of the method are advantageous in which the outlet valve of the at least one outlet opening is actuated for the purpose of carrying out the additional valve lift Δh add, exhaust , while the at least one inlet opening of the cylinder is closed at least temporarily.
  • In the present case, the inlet valve of the at least one inlet opening is at least temporarily closed during the complete execution of the additional valve lift. This prevents that at a pressure gradient between the intake system and the Abgasabführsystem the supplied via the inlet port air flows through the cylinder without the exhaust gas is returned in the context of an internal exhaust gas recirculation into the cylinder.
  • Embodiments of the method in which the outlet valve of the at least one outlet opening is only actuated for the purpose of carrying out the additional valve lift are therefore advantageous if there is a pressure gradient such that the pressure in the exhaust gas removal system is greater than the pressure in the intake system or in the cylinder. This is of particular relevance to supercharged internal combustion engines.
  • A pressure gradient between the Abgasabführsystem and the intake system or the cylinder supports the backflow of exhaust gas into the cylinder.
  • The invention will be described in more detail below with reference to three valve lift curves and FIGS. 1, 2 and 3. Hereby shows:
    • 1 in a diagram, the valve lift curve h exhaust an exhaust valve in normal operation of the supercharged internal combustion engine,
    • 2 in a diagram, the valve lift curve h exhaust of an exhaust valve with an early opening of the exhaust valve, and
    • 3 in a diagram the valve lift curve h exhaust of an exhaust valve with an additional stroke Δh add, exhaust .
  • 1 shows in a diagram the valve lift curve h exhaust an exhaust valve in normal operation of the supercharged internal combustion engine.
  • During the charge cycle, the exhaust gas is evacuated from the cylinder by opening the exhaust valve and the maximum valve lift Δh max, exhaust performs. In the present case, the exhaust valve closes after top dead center OT , ie in the intake phase, in which the piston moves in the direction of the bottom dead center.
  • 2 shows in a diagram the valve lift curve h exhaust an exhaust valve with an early opening of the exhaust valve. Compared to the in 1 shown valve lift curve opens the exhaust valve earlier to quickly raise the temperature in the exhaust system of the internal combustion engine, for example, after a cold start. In the present case, the exhaust valve opens during combustion in the expansion phase, in which the piston moves in the direction of the bottom dead center.
  • 3 shows in a diagram the valve lift curve h exhaust an exhaust valve with an additional stroke Δh add, exhaust , The exhaust valve is actuated in such a way that this exhaust valve an additional valve lift Δh add, exhaust performs.
  • After the exhaust valve has carried out the maximum valve lift .DELTA.h max, exhaust during the charge cycle and before the piston reaches bottom dead center during intake, the exhaust valve is opened again.
  • The additional valve lift Δh add, exhaust the exhaust valve is used for the internal exhaust gas recirculation and thus the raising of the average exhaust gas temperature. The temperature in the exhaust system of the internal combustion engine is moderately increased in this way.
  • In the present case, the exhaust valve is after completion of the maximum valve lift Δh max, exhaust only transferred back to the closed position during the change of charge, before this exhaust valve for the purpose of completing the additional valve lift Δh add, exhaust reopened.
  • LIST OF REFERENCE NUMBERS
  • h exhaust
    Valve lift of an exhaust valve
    Δh max, exhaust
    maximum valve lift of an exhaust valve
    Δh add, exhaust
    additional valve lift of an exhaust valve
    ° CA
    Degree crank angle
    Δt exhaust
    Opening duration of an exhaust valve
    OT
    Top Dead Center
    UT
    bottom dead center

Claims (17)

  1. A supercharged internal combustion engine having at least one cylinder head with at least one cylinder, in which - each cylinder has at least one inlet opening for supplying combustion air via the intake system and at least two outlet openings for discharging the exhaust gases via Abgasabführsystem and has a piston which along a Piston longitudinal axis between a bottom dead center and a top dead center is movable, - the cylinder-associated openings are each equipped with a valve train comprising a valve, the use of an actuator along a longitudinal axis between a valve closed position and a valve open position under full control of a maximum valve lift .DELTA.h max, exhaust movable is to release the opening in the context of a charge exchange during an opening period .DELTA.t exhaust or obstruct, - the valvetrain of at least one outlet opening is at least partially variable in such a way that the control time at which the associated outlet valve is opened, is displaced early, and - at least one exhaust aftertreatment system is provided in the Abgasabführsystem, characterized in that - the valve train of at least one outlet opening is at least partially variable in the way that the associated outlet valve in the manner is actuated that this exhaust valve performs an additional valve lift .DELTA.h add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve in the context of the charge change the maximum valve lift .DELTA.h max, exhaust has performed.
  2. Charged internal combustion engine after Claim 1 , characterized in that - the valve train of at least two outlet openings is at least partially variable in the way that the control time at which the associated outlet valve is opened, is displaced to early.
  3. Charged internal combustion engine after Claim 1 or 2 , characterized in that - the valvetrain of at least two outlet openings is at least partially variable in the way that the associated exhaust valve is actuated in such a way that this exhaust valve performs an additional valve lift Δh add, exhaust before the piston in the context of the charge cycle the lower Dead center reached and after the exhaust valve in the context of the charge change the maximum valve lift Δh max, exhaust has performed.
  4. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the valve train of at least two outlet openings is at least partially variable in the way that - the control time at which the associated outlet valve is opened, is displaced to early, and - the associated outlet valve in the manner is operable, that this exhaust valve performs an additional valve lift .DELTA.h add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve in the context of the charge change the maximum valve lift .DELTA.h max, exhaust has performed.
  5. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the additional valve lift Δh add, exhaust is less than one third of the maximum valve lift Δh max, exhaust .
  6. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the additional valve lift .DELTA.h add, exhaust is less than a quarter of the maximum valve lift .DELTA.h max, exhaust .
  7. Supercharged internal combustion engine according to one of the preceding claims, characterized in that each cylinder has two outlet openings for discharging the exhaust gases via Abgasabführsystem.
  8. Charged internal combustion engine after Claim 7 characterized in that the valvetrain of each exhaust port is at least partially variable in the manner that - the timing at which the associated exhaust valve is opened is displaceable early, and - the associated exhaust valve is operable in such a manner that this exhaust valve engages additional valve lift Δh add, exhaust occurs before the piston reaches the bottom dead center during the charge cycle and after the exhaust valve has performed the maximum valve lift Δh max, exhaust during the charge cycle.
  9. Charged internal combustion engine after Claim 7 characterized in that - the valvetrain of a first exhaust port is at least partially variable in the manner that the timing at which the associated exhaust valve is opened is displaceable early, and - the valvetrain of a second exhaust port is at least partially variable in type in that the associated outlet valve can be actuated in such a way that this outlet valve performs an additional valve lift Δh add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve has carried out the maximum valve lift Δh max, exhaust during the charge cycle.
  10. Method for operating a supercharged internal combustion engine according to one of the preceding claims, characterized in that the temperature in the exhaust gas discharge system is increased by - the exhaust valve of at least one outlet opening is opened earlier, or - the exhaust valve of at least one outlet opening is actuated in such a way that this exhaust valve performs an additional valve lift .DELTA.h add, exhaust before the piston reaches the bottom dead center in the context of the charge cycle and after the exhaust valve has been actuated in the course of the charge cycle under full control the maximum valve lift .DELTA.h max, exhaust .
  11. Method according to Claim 10 characterized in that the temperature in the exhaust gas discharge system is increased by - the exhaust valve of at least one outlet opening being opened sooner, if a rapid increase in the temperature is required, or - the exhaust valve of at least one outlet opening is operated in such a way that this outlet valve has an additional Valve lift .DELTA.h add, exhaust occurs before the piston reaches bottom dead center during the charge cycle and after the exhaust valve has been fully actuated to actuate the maximum valve lift .DELTA.h max, exhaust if a moderate, less rapid increase in temperature is required.
  12. Method according to Claim 10 or 11 for operating a supercharged internal combustion engine Claim 8 characterized in that the temperature in the exhaust gas discharge system is increased by - the exhaust valves of both exhaust ports are opened earlier, or - the exhaust valves of both exhaust ports are operated such that each exhaust valve performs an additional valve lift Δh add, exhaust before the piston in the frame the charge cycle reaches the bottom dead center and after the exhaust valve has been operated in the context of the charge cycle under full control the maximum valve lift Δh max, exhaust .
  13. Method according to Claim 10 or 11 for operating a supercharged internal combustion engine Claim 9 , characterized in that the temperature in the Abgasabführsystem is increased by - the exhaust valve of a first exhaust port is opened earlier, or - the exhaust valve of a second exhaust port is actuated in such a way that this exhaust valve performs an additional valve lift .DELTA.h add, exhaust before the piston reached in the context of the charge change the bottom dead center and after the exhaust valve in the context of the charge change under full control the maximum valve lift Δh max, exhaust was actuated.
  14. Method according to one of Claims 10 to 13 , characterized in that the additional valve lift Δh add, exhaust the exhaust valve is performed up to 80 ° CA before bottom dead center.
  15. Method according to one of Claims 10 to 13 , characterized in that the additional valve lift .DELTA.h add, exhaust the exhaust valve is performed up to 60 ° CA before bottom dead center.
  16. Method according to one of Claims 10 to 15 , characterized in that the exhaust valve of the at least one outlet opening after completion of the maximum valve lift .DELTA.h max, exhaust is transferred again in the closed position in the context of the charge cycle before this exhaust valve to complete the additional valve lift .DELTA.h add, exhaust is reopened.
  17. Method according to one of Claims 10 to 16 , characterized in that the exhaust valve of the at least one outlet opening for the purpose of complete execution of the additional valve lift Δh add, exhaust is actuated, while at least one inlet opening of the cylinder is at least temporarily closed.
DE102017200739.7A 2017-01-18 2017-01-18 Charged internal combustion engine with exhaust aftertreatment and method for operating such an internal combustion engine Pending DE102017200739A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3089562A1 (en) * 2018-12-07 2020-06-12 Renault S.A.S Method for controlling a supercharged internal combustion engine

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DE102005015853A1 (en) 2005-04-07 2006-10-26 Daimlerchrysler Ag Stroke-piston internal combustion engine operation, involves reducing external recirculation of exhaust gases during regeneration operation and controlling exhaust valves, so that internal recirculation of exhaust gases is activated
DE102005015852A1 (en) 2005-04-07 2006-10-26 Daimlerchrysler Ag Reciprocating internal combustion engine for use in vehicle, has cams one of which is switched in cold start and cold running phase, where elevations are operated during respective phases
US20080127952A1 (en) 2004-10-20 2008-06-05 Koichi Hatamura Engine
EP2698518A1 (en) 2011-04-13 2014-02-19 Toyota Jidosha Kabushiki Kaisha Internal combustion engine control apparatus
GB2520017A (en) 2013-11-05 2015-05-13 Univ Brunel Dual fuel internal combustion engine

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Publication number Priority date Publication date Assignee Title
US20080127952A1 (en) 2004-10-20 2008-06-05 Koichi Hatamura Engine
DE102005015853A1 (en) 2005-04-07 2006-10-26 Daimlerchrysler Ag Stroke-piston internal combustion engine operation, involves reducing external recirculation of exhaust gases during regeneration operation and controlling exhaust valves, so that internal recirculation of exhaust gases is activated
DE102005015852A1 (en) 2005-04-07 2006-10-26 Daimlerchrysler Ag Reciprocating internal combustion engine for use in vehicle, has cams one of which is switched in cold start and cold running phase, where elevations are operated during respective phases
EP2698518A1 (en) 2011-04-13 2014-02-19 Toyota Jidosha Kabushiki Kaisha Internal combustion engine control apparatus
GB2520017A (en) 2013-11-05 2015-05-13 Univ Brunel Dual fuel internal combustion engine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3089562A1 (en) * 2018-12-07 2020-06-12 Renault S.A.S Method for controlling a supercharged internal combustion engine

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