CN110578627A - Supercharged internal combustion engine with a compressor and method for operating an internal combustion engine of said type - Google Patents

Supercharged internal combustion engine with a compressor and method for operating an internal combustion engine of said type Download PDF

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Publication number
CN110578627A
CN110578627A CN201910484660.4A CN201910484660A CN110578627A CN 110578627 A CN110578627 A CN 110578627A CN 201910484660 A CN201910484660 A CN 201910484660A CN 110578627 A CN110578627 A CN 110578627A
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CN
China
Prior art keywords
internal combustion
combustion engine
compressor
exhaust gas
phase change
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
CN201910484660.4A
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Chinese (zh)
Inventor
A·库斯克
C·维吉尔德
H·G·奎科斯
G·格罗斯切
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Ford Global Technologies LLC
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Ford Global Technologies LLC
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Publication of CN110578627A publication Critical patent/CN110578627A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/10—Final actuators
    • F01D17/12—Final actuators arranged in stator parts
    • F01D17/14—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits
    • F01D17/141—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of shiftable members or valves obturating part of the flow path
    • F01D17/145—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of shiftable members or valves obturating part of the flow path by means of valves, e.g. for steam turbines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/22—Control of the pumps by varying cross-section of exhaust passages or air passages, e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/22—Control of the pumps by varying cross-section of exhaust passages or air passages, e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits
    • F02B37/225—Control of the pumps by varying cross-section of exhaust passages or air passages, e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits air passages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/02—EGR systems specially adapted for supercharged engines
    • F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
    • F02M26/06—Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M31/00—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture
    • F02M31/02—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture for heating
    • F02M31/04—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture for heating combustion-air or fuel-air mixture
    • F02M31/06—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture for heating combustion-air or fuel-air mixture by hot gases, e.g. by mixing cold and hot air
    • F02M31/08—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture for heating combustion-air or fuel-air mixture by hot gases, e.g. by mixing cold and hot air the gases being exhaust gases
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Supercharger (AREA)
  • Exhaust-Gas Circulating Devices (AREA)

Abstract

The invention discloses a supercharged internal combustion engine with a compressor and a method for operating an internal combustion engine of said type. The invention relates to a supercharged internal combustion engine, comprising: an air intake system (1) for supplying charge air; an exhaust gas discharge system for discharging exhaust gas; and at least one compressor (2) arranged for compressing a charge air flow in the air intake system (1), the compressor comprising at least one impeller (2d) equipped to a rotatable shaft and with impeller blades in a compressor housing (2 c). The object of the invention is to provide an internal combustion engine of the type mentioned, by means of which the formation of condensate in the compressor housing (2c) can be counteracted. This is achieved by an internal combustion engine with the following differences: the compressor housing (2c) is equipped with a phase change material (4) upstream of the at least one compressor wheel (2d), the phase change material (4) being present as a liquid phase or as a solid phase, the phase change material (4) absorbing heat or releasing heat during a phase change.

Description

Supercharged internal combustion engine with a compressor and method for operating an internal combustion engine of said type
Technical Field
The invention relates to a supercharged internal combustion engine, comprising: an intake system for supplying charge air; an exhaust gas discharge system for discharging exhaust gas; and at least one compressor arranged for compressing a charge air flow in the intake system, the compressor comprising at least one impeller equipped to a rotatable shaft in a compressor housing and equipped with impeller blades. The invention also relates to a method for operating an internal combustion engine of said type.
Background
Internal combustion engines of the type described are used as motor vehicle drive units. Within the context of the present invention, the term "internal combustion engine" includes diesel engines and otto-cycle engines, but also hybrid internal combustion engines, i.e. internal combustion engines which operate with a hybrid combustion process and a hybrid drive which, in addition to the internal combustion engine, also comprises at least one further torque source (e.g. an electric machine) for driving the motor vehicle, which electric machine is drivingly connectable or drivingly connected to the internal combustion engine and outputs power instead of or in addition to the internal combustion engine.
In the development of internal combustion engines, it is constantly sought to minimize fuel consumption. Furthermore, in order to be able to comply with future limits of pollutant emissions, a reduction of pollutant emissions is sought.
Internal combustion engines are more commonly equipped with supercharging devices, where supercharging is primarily the method for increasing power, in which the charge air required for the combustion process in the engine is compressed, so that each working cycle can supply a greater mass of charge air to each cylinder. In this way, the fuel mass, and thus the mean pressure, may be increased.
Supercharging is a suitable device for increasing the power of an internal combustion engine while maintaining a constant scavenging volume or for reducing the scavenging volume while maintaining the same power. In all cases, the boost results in an increase in volumetric power output and a more favorable power-to-weight ratio. Therefore, if the scavenging volume is reduced, the load can be collectively moved to a higher load at which the specific fuel consumption rate is lower. By combining supercharging with a suitable transmission configuration, so-called deceleration can also be achieved, as can a lower specific fuel consumption.
Therefore, supercharging contributes to the ongoing development of internal combustion engines to minimize fuel consumption, i.e., to increase the efficiency of the internal combustion engine.
For supercharging, exhaust gas turbochargers are generally used, in which the compressor and the turbine are arranged on the same shaft. The hot exhaust gas flow is fed to the turbine and expands in the turbine in a manner that releases energy, as a result of which the shaft is set in rotation. The energy released by the exhaust gas flow to the turbine and ultimately to the shaft is used to drive a compressor also disposed on the shaft. The compressor delivers and compresses the charge air supplied to it, thereby achieving a supercharging of the cylinder.
A charge air cooler is advantageously arranged in the intake system downstream of the compressor, by means of which charge air that is compressed is cooled before it enters the at least one cylinder. The cooler reduces the temperature and thus increases the density of the charge air, so that the cooler also contributes to an improved charging of the cylinder, that is to say with a greater air mass. Compression is carried out by cooling.
An advantage of an exhaust-gas turbocharger over a supercharger is that the exhaust-gas turbocharger utilizes the exhaust-gas energy of the hot exhaust gases, while the supercharger draws the energy required for driving it directly or indirectly from the internal combustion engine. Generally, to transfer power between the supercharger and the internal combustion engine, a mechanical connection, such as a traction mechanism drive, is required.
An advantage of a supercharger over an exhaust-gas turbocharger is that, in general, a supercharger can generate and make available a required boost pressure independently of the current operating state of the internal combustion engine, in particular at low rotational speeds of the crankshaft. This applies in particular to superchargers which can be driven by an electric motor and can therefore also be referred to as electric superchargers.
In the prior art, there are in particular situations where difficulties are encountered in achieving power increase through exhaust turbocharging over all engine speed ranges. A relatively severe torque drop is observed in certain engine underspeets. The torque drop is understandable if it is considered that the boost pressure ratio depends on the turbine pressure ratio. If the engine speed decreases, a smaller exhaust gas mass flow and thus a lower turbine pressure ratio result, so the charging pressure ratio likewise decreases towards lower engine speeds. This equates to a torque drop.
For supercharging purposes, the invention relates to a supercharged internal combustion engine having at least one compressor, which may be the compressor of a supercharger, an electric supercharger or an exhaust-gas turbocharger.
in particular, if the internal combustion engine is equipped with an exhaust gas recirculation device in which exhaust gas is introduced into the intake system upstream of the compressor, problems may arise upstream of the compressor. In particular, a condensate may be formed. In this case, a plurality of scenes must be allowed.
First, if the recirculated hot exhaust gas meets and mixes with cold fresh air, condensate may form. The exhaust gas cools and the temperature of the fresh air increases. The temperature of the mixture of fresh air and recirculated exhaust gas (i.e., the charge air temperature) is lower than the exhaust gas temperature of the recirculated exhaust gas. During the process of cooling the exhaust gas, if the dew point temperature of the constituents of the gaseous charge air stream is insufficient, the liquid (in particular water) previously contained in the exhaust gas still in gaseous form may condense.
Condensate formation occurs in the free charge air flow, wherein contaminants in the charge air generally form starting points for the formation of condensate droplets.
Secondly, when the recirculated hot exhaust gas and/or charge air hits the inner wall of the intake system or the inner wall of the compressor housing, condensate may form, since the wall temperature is typically below the dew point temperature of the relevant gaseous components.
The above-described problem is exacerbated as the recirculation rate increases, because as the flow rate of recirculated exhaust gas increases, the fraction of the individual exhaust gas components in the charge air (in particular the fraction of water contained in the exhaust gas) inevitably increases. Therefore, in the prior art, in order to prevent or reduce the occurrence of condensation, the flow rate of exhaust gas recirculated through the low-pressure EGR device is generally limited. The required limitation of low-pressure EGR on the one hand and the high exhaust gas recirculation rate required for a significant reduction in nitrogen oxide emissions on the other hand lead to different objectives in the dimensioning of the recirculated exhaust gas flow. The legal requirements for reducing nitrogen oxide emissions highlight the high relevance of this problem in practice.
The effects described above in connection with hot exhaust gas recirculation apply similarly to the ventilation flow, which is typically drawn from the crankcase and introduced into the intake system upstream of the compressor.
Condensate formation in the intake system is a fundamental problem, especially in internal combustion engines without a low-pressure EGR device or with a deactivated low-pressure EGR device.
Condensate and condensate droplets are undesirable and result in increased noise emissions in the air intake system and may damage the blades of the at least one compressor wheel. The latter effect is associated with a reduction in compressor efficiency.
US8,297,922B1 describes a shroud for protecting the impeller of a compressor from damage and deposits. The housing constitutes an additional weight which rotates with the rotating impeller of the compressor, with correspondingly high forces acting on the compressor shaft and in the bearings. The response performance of the compressor is greatly affected since the heavy casing and therefore the rotating impeller of the compressor must be accelerated and decelerated.
Alternatively, the compressor according to the prior art is equipped with a heating device by means of which the temperature of the inner wall of the compressor housing can be increased. In this way, condensate formation on the inner wall of the intake system or on the inner wall of the compressor housing can be prevented or reduced. This is a cumbersome and expensive concept.
Disclosure of Invention
Against this background, it is an object of the present invention to provide a supercharged internal combustion engine according to the preamble of claim 1, by means of which the disadvantages known from the prior art are overcome and by means of which the formation of condensate in the compressor housing can be counteracted.
A further sub-category of the invention is to specify a method of operating an internal combustion engine of the type in question.
The first sub-group is realized by a supercharged internal combustion engine having:
An air intake system for supplying pressurized air,
An exhaust gas discharge system for discharging exhaust gas, an
At least one compressor arranged for compressing a charge air stream in an air intake system, the compressor comprising at least one impeller mounted on a rotatable shaft in a compressor housing and provided with impeller blades,
The internal combustion engine is distinguished in that:
The compressor housing is equipped upstream of the at least one compressor wheel with a phase change material, which is present as a liquid phase or as a solid phase, which absorbs or releases heat during a phase change.
At least one compressor of the internal combustion engine according to the invention is equipped with a phase change material by means of which the temperature of the inner wall of the compressor housing can be increased when required, for example before or during a cold start of the internal combustion engine. By warming, the wall temperature may be increased above the dew point temperature of the pressurized air or the gaseous components of the recirculated exhaust gas.
In this way, condensate formation on the inner wall of the intake system or on the inner wall of the compressor housing can be prevented or reduced.
By preventing the formation of condensate in the air intake system and in the inlet region of the compressor, the increase in noise emissions due to condensate droplets is also eliminated. The risk of damage to the impeller blades of at least one compressor is eliminated.
When needed, the phase change material is activated, for example mechanically or electrically, so that heat is released and introduced into the compressor housing. Here, the phase change material undergoes a phase change from a liquid phase to a solid phase and vice versa, depending on the material used.
In order to prepare the phase change material again for the next implementation or for the next use, heat must be supplied, wherein the phase change material undergoes a phase change again during this regeneration, in particular in the opposite direction, i.e. from the solid phase back to the liquid phase or vice versa.
Phase change materials release or absorb heat during phase change. That is, the material acts as a heat sink (i.e., as a heat-absorbing energy storage), or as a heat-releasing heating device.
The first object on which the invention is based is achieved by an internal combustion engine according to the invention in that an internal combustion engine according to the preamble of claim 1 is provided, by means of which the disadvantages known from the prior art can be overcome and by means of which the formation of condensate in the compressor housing can be counteracted.
The compressor housing according to the invention must have at least one cavity or at least one container for receiving the phase change material. The cavity or container for receiving the phase change material may be formed as an integrated part of the housing during the production process. The housing may be constructed in a modular manner, wherein a cavity for receiving the phase change material is formed during the assembly process.
the cavity may be formed by the shell itself being provided with a casing (casting) such that the cavity receiving the phase change material is formed between the shell and at least one shell element arranged spaced therefrom. The shell then expands to include an outer shell, then a container for receiving the phase change material.
For the above reasons, the following embodiments of a supercharged internal combustion engine are advantageous, wherein the compressor housing comprises at least one cavity for receiving the phase change material.
The following embodiments of a supercharged internal combustion engine are advantageous in which the at least one cavity is formed by using at least in particular a housing element.
Thus, the housing need not be a pure casting in which the at least one cavity is formed as an integral component during the casting process. Instead, the expansion shell is preferably an assembly system, for example consisting of sheet metal, in which case at least one cavity is formed during the assembly process using shell elements arranged at intervals. This also creates the possibility of retrofitting compressors that are already on the market or are already designed.
Another advantageous embodiment of a supercharged internal combustion engine will be discussed together with the subclaims.
The following embodiments of a supercharged internal combustion engine are advantageous in which the phase change material releases heat during the phase change from the liquid phase to the solid phase.
Here, the following embodiments of a supercharged internal combustion engine are advantageous, wherein the phase change material absorbs heat during the phase change from the solid phase to the liquid phase.
The following embodiments of a supercharged internal combustion engine are advantageous in which the phase change material releases heat during the phase change from the solid phase to the liquid phase.
By targeted configuration of the supercharging, advantages with regard to exhaust emissions can be achieved. By means of a suitable supercharging (for example of a diesel engine), the nitrogen oxide emissions can thus be reduced without any loss in efficiency. At the same time, hydrocarbon emissions can be positively influenced. The emission of carbon dioxide, which is directly related to fuel consumption, also decreases as fuel consumption decreases.
However, in order to comply with future limits of pollutant emissions, further measures are required. Exhaust Gas Recirculation (EGR), i.e. recirculation of combustion gases from the outlet side to the inlet side, is considered to be advantageous for a significant reduction of nitrogen oxide emissions. Here, the exhaust gas recirculation rate xEGRIs determined as xEGR＝mEGR/(mEGR+mfresh air) Wherein m isEGRIndicating recirculationMass of exhaust, mfresh airIndicating the supply of fresh air. It may be necessary to take into account the oxygen provided via exhaust gas recirculation.
Therefore, the following embodiments of a supercharged internal combustion engine, in which an exhaust gas recirculation arrangement is provided, are advantageous.
In this case, an embodiment of the supercharged internal combustion engine is advantageous in which an exhaust gas recirculation device is provided which has a recirculation line to the intake system in order to form a first junction upstream of the at least one compressor wheel.
in this case, the exhaust gas recirculation device may be a high-pressure EGR device that draws exhaust gas from the exhaust gas exhaust system upstream of the turbine of the exhaust turbocharger and introduces the exhaust gas into the intake system, or the exhaust gas recirculation device may be a low-pressure EGR device whereby exhaust gas that has passed through the turbine is recirculated to the inlet side. The low-pressure EGR device comprises a recirculation line which branches off from the exhaust-gas outlet system downstream of the turbine and opens into the intake system upstream of the compressor.
The main advantage of a low-pressure EGR device over a high-pressure EGR device is that the exhaust flow introduced into the turbine during exhaust gas recirculation is not reduced by the recirculated exhaust gas flow. The entire exhaust flow is always available at the turbine to generate a sufficiently high boost pressure.
The exhaust gas which is recirculated to the inlet side via the low-pressure EGR device and is preferably cooled is mixed with fresh air upstream of the compressor. The mixture of fresh air and recirculated exhaust gas produced in this way forms the charge air which is supplied to the compressor and compressed.
Here, the fact that the exhaust gas is conducted through the compressor during the low-pressure EGR process is not detrimental, since it is preferable to use exhaust gas which has already been subjected to exhaust gas aftertreatment (in particular a particulate filter) downstream of the turbine. Therefore, there is no risk of deposits in the compressor, which alter the geometry of the compressor, in particular the flow cross section, and thus impair the efficiency of the compressor.
According to the present invention, the formation of condensate on the inner wall of the compressor housing can be prevented or reduced. In this respect, there is no need to limit the flow rate of exhaust gas recirculated by low-pressure EGR, so that a high recirculation rate by low-pressure EGR can be achieved in order to obtain a significant reduction in nitrogen oxide emissions.
However, in addition to the low-pressure EGR device, a high-pressure EGR device may also be used, in which case exhaust gas is extracted from the exhaust gas discharge system upstream of the turbine of the exhaust turbocharger and introduced into the intake system downstream or upstream of the compressor.
The following embodiments of a supercharged internal combustion engine are advantageous in which the exhaust gas recirculation arrangement comprises a throttle element for regulating the flow of recirculated exhaust gas. In particular, embodiments are advantageous in which the throttling element is arranged at the first junction. The following exemplary embodiments are particularly advantageous, with the difference that the throttle element is a combination valve, by means of which the flow rate of the recirculated exhaust gas and the fresh air flow rate can be adjusted.
the following embodiments of a supercharged internal combustion engine are advantageous in which the at least one compressor arranged in the intake system belongs to an exhaust-gas turbocharger comprising a turbine arranged in the exhaust-gas discharge system and a compressor arranged in the intake system. Supercharging is a measure for minimizing fuel consumption, i.e. improving the efficiency of an internal combustion engine.
Various measures can be used to improve the torque characteristics of an internal combustion engine that is supercharged by exhaust turbocharging.
For example, one such measure is the small turbine cross-sectional design and the simultaneous provision of an exhaust blow-off device. For this purpose, the turbine is equipped with a blow-off line which branches off from the exhaust-gas discharge system upstream of the turbine, and in which a throttle element is arranged. Such turbines are also referred to as wastegate turbines. If the exhaust gas mass flow exceeds a threshold value, a part of the exhaust gas flow is conducted through the turbine via a blow-out line during a so-called exhaust gas blow-out process, i.e. blown out. The disadvantage of this approach is that the high energy blowoff exhaust gas remains unutilized and boost performance is often inadequate at higher engine speeds.
Turbines with variable turbine geometry allow engine speed-or load-based adjustment of the turbine geometry to a certain extent by adjusting the turbine geometry or the effective turbine cross section to more finely adapt the respective operating point of the internal combustion engine.
The torque characteristics of a supercharged internal combustion engine can also be improved by: arranging a plurality of turbochargers in parallel, that is to say a plurality of turbines of relatively small turbine cross section in parallel, activates the turbines successively with increasing exhaust gas flow, similarly to a sequential supercharging.
The torque characteristics can also be favorably influenced by a plurality of exhaust gas turbochargers connected in series. By connecting two exhaust-gas turbochargers in series, one of which serves as a high-pressure stage and one of which serves as a low-pressure stage, the compressor characteristic map can advantageously be expanded, in particular in the direction of a smaller compressor flow and in the direction of a larger compressor flow.
In addition to an exhaust-gas turbocharger, a mechanical or electrical supercharger may also be provided. Since an exhaust turbo-charging device (particularly, an exhaust turbo-charging device using a plurality of exhaust turbochargers) is expensive, supercharging may be performed by a mechanical or electric supercharger instead of the exhaust turbo-charging. These advantages are those already described above.
the following embodiment of a supercharged internal combustion engine is advantageous in which the compressor has an inlet region which extends coaxially with respect to the shaft of the compressor and which is designed such that the intake air flow approaching the compressor extends substantially axially.
In the case of an axial inflow compressor, the reversal or change of direction of the intake air flow in the intake system upstream of the at least one compressor wheel is usually omitted, whereby unnecessary pressure losses in the intake air flow due to flow reversal are avoided and the pressure of the charge air entering the compressor of the exhaust-gas turbocharger at the inlet is increased. The absence of a change in direction also reduces contact of exhaust gas and/or charge air with the inner walls of the air intake system and/or with the inner walls of the compressor housing, and thus reduces heat transfer and condensate formation.
In the case of a supercharged internal combustion engine equipped with an exhaust-gas turbocharger and an exhaust-gas recirculation device, the following embodiments can be advantageous, with the difference that the recirculation line branches off from the exhaust-gas outlet system, so that a second junction is formed downstream of the turbine of the exhaust-gas turbocharger. These advantages are those already explained in connection with the description of the low-pressure EGR device.
In this case, an embodiment of the supercharged internal combustion engine is advantageous in which the first throttle element is arranged in the exhaust gas outlet system downstream of the second junction.
Here, the recirculation line branches off from the exhaust-gas discharge system between the turbine and the first throttle element. The first throttle element may be used to increase the upstream exhaust gas pressure in the exhaust outlet system and thus facilitate and may be used to increase the pressure gradient between the exhaust outlet system and the intake system. This provides advantages especially in the case of high recirculation rates requiring large pressure gradients.
In conjunction with an exhaust gas recirculation device, the following embodiment of a supercharged internal combustion engine is likewise advantageous, in which the second throttle element is arranged in the intake system upstream of the first junction. The second throttle element serves on the inlet side for reducing the pressure in the intake system and, therefore, as with the first throttle element, contributes to increasing the pressure gradient between the exhaust gas outlet system and the intake system.
The following embodiments of the supercharged internal combustion engine are advantageous in which the first throttle element and/or the second throttle element is a pivotable flap.
The following embodiments of a supercharged internal combustion engine may be advantageous, wherein the compressor is a radial compressor. In the case of an exhaust-gas turbocharger, this embodiment allows for dense packaging. The compressor housing can be a spiral or worm-shaped housing, wherein the reversal of the charge air flow in the compressor of the exhaust-gas turbocharger can advantageously be used to conduct the compressed charge air on the shortest path from the outlet side, on which the turbine of the exhaust-gas turbocharger is usually arranged, to the inlet side.
In this case, the following embodiment of the internal combustion engine is advantageous, wherein the turbine of the exhaust-gas turbocharger is a radial turbine. This embodiment also allows for a dense packing of the exhaust-gas turbocharger and thus of the supercharging device as a whole.
In contrast to turbines, compressors are defined according to their outlet flow. Thus, a radial compressor is a compressor in which the flow leaving the rotor blades extends substantially radially. In the context of the present invention, "substantially radial" means that the velocity component in the radial direction is greater than the axial velocity component.
The following embodiments of a supercharged internal combustion engine may also be advantageous, wherein the compressor is an axial compressor. The flow leaving the impeller blades of an axial compressor extends substantially axially.
The following embodiment of a supercharged internal combustion engine is advantageous in which the compressor housing is equipped with a heating device upstream of the at least one compressor wheel.
The heating device can be activated at any time and used to regenerate the phase change material by supplying heat, and if desired, it can warm the inner wall of the compressor housing instead of or in addition to the phase change material.
In this case, an embodiment of the supercharged internal combustion engine is advantageous in which the heating device comprises at least one electrically heatable line integrated in the compressor housing.
The electric heating apparatus may be powered, for example, by an on-board battery of the vehicle, regardless of the operating state of the internal combustion engine. The wire may already be incorporated during the production of the compressor housing, for example by casting into the compressor housing. In this way a high level of heat transfer from the wire to the housing is ensured or achieved.
In this context, the following embodiments of a supercharged internal combustion engine may also be advantageous, wherein the heating device comprises at least one duct which is arranged in the compressor housing and which can be filled with a fluid. Internal combustion engines typically have a variety of operating fluids that may be used or implemented for introducing heat into the housing, such as coolant of a liquid-type cooling device or oil from an oil circuit of the internal combustion engine.
In this case, an embodiment of the supercharged internal combustion engine is advantageous in which at least one duct is connectable at least to the exhaust gas outlet system. In this case, the hot exhaust gas is used to introduce heat into the housing, wherein the exhaust gas can be drawn off from an exhaust gas discharge system or an exhaust gas recirculation device.
In the case of a supercharged internal combustion engine with a liquid-type cooling device, the following embodiments in this case are advantageous, with the difference that at least one duct can be connected at least to the liquid-type cooling device.
Embodiments of a supercharged internal combustion engine in which the intake system is equipped upstream of the at least one compressor wheel or compressor housing with a phase change material which is present as a liquid phase or as a solid phase, the phase change material absorbing heat or releasing heat during the phase change, can be advantageous. Instead of or in addition to the compressor housing, the air intake system may be substantially equipped with a phase change material.
The second sub-object on which the invention is based is achieved by a method, in particular specifying a method of operating an internal combustion engine of the type described above, which differs in that the phase change materials are activated sequentially during the phase change in order to release heat to warm the compressor housing.
What has been explained in relation to the internal combustion engine according to the invention also applies to the method according to the invention, for which reason reference is generally made to the statements made above in relation to a supercharged internal combustion engine. Different internal combustion engines require partially different method variants.
A method variant may be advantageous in which the phase change material is activated before or during a cold start, for example by means of an ignition switch.
A method variant is advantageous in which the phase change material is warmed and indirectly regenerated by compressed charge air.
A method variant is advantageous in which the phase change material is warmed and regenerated by means of hot exhaust gases.
A process variant is advantageous in which the phase change material is warmed and regenerated by means of a warmed cooling liquid or hot oil.
Drawings
The invention will be described in more detail below on the basis of the exemplary embodiment according to fig. 1. In the drawings:
Fig. 1 schematically shows, in a partial section, a compressor of a first embodiment of an internal combustion engine arranged in an air intake system.
Fig. 1 schematically shows, in a partial section, a compressor 2 of a first embodiment of an internal combustion engine arranged in an intake system 1.
Detailed Description
for supplying the cylinders with charge air, the internal combustion engine has an intake system 1, and for supercharging the cylinders, an exhaust-gas turbocharger is provided, which comprises a turbine (not shown) arranged in an exhaust-gas discharge system and a compressor 2 arranged in the intake system 1. The compressor 2 is a radial compressor 2b in a housing 2c, and an impeller 2d of the radial compressor 2b is mounted on a rotatable shaft.
the compressor 2 of the exhaust-gas turbocharger has an inlet region 2a which extends coaxially with respect to the axis of the compressor 2 and which inlet region 2a is designed such that the charge air flow approaching the compressor 2 of the exhaust-gas turbocharger extends substantially axially and the portion of the intake system 1 upstream of the compressor 2 does not change in direction.
The internal combustion engine is also equipped with an exhaust gas recirculation arrangement comprising a recirculation line which branches off from the exhaust gas discharge system downstream of the turbine and which leads (not shown) to the intake system 1, so that a first junction is formed upstream of the compressor 2 or the compressor wheel 2 d.
The compressor housing 2c is equipped with a phase change material 4 upstream of the compressor wheel 2d, which phase change material 4 is present as a liquid phase or as a solid phase and absorbs or releases heat during the phase change process. In the present case, the phase change material 4 is located in a cavity 3 in the compressor housing 2 c.
Reference numerals
1 air intake system
2 compressor
2a inlet area of a compressor
2b radial compressor
2c compressor housing
2d impeller
3 hollow cavity
4 phase change material
EGR exhaust gas recirculation
mEGRMass of recirculated exhaust gas
mfresh airQuality of fresh air or charge air supplied
xEGRExhaust gas recirculation rate

Claims (17)

1. A supercharged internal combustion engine having:
An air intake system (1) for supplying charge air;
An exhaust gas discharge system for discharging exhaust gas; and
At least one compressor (2) arranged for compressing a flow of charge air in the air intake system (1), the compressor comprising at least one impeller (2d), the impeller (2d) being mounted to a rotatable shaft in a compressor housing (2c) and being equipped with impeller blades;
Wherein the content of the first and second substances,
The compressor housing (2c) is equipped with a phase change material (4) upstream of the at least one compressor wheel (2d), the phase change material (4) being present as a liquid phase or as a solid phase, the phase change material (4) absorbing or releasing heat during a phase change.
2. A charged internal combustion engine according to claim 1, wherein the phase change material (4) releases heat during the phase change from the liquid phase to the solid phase.
3. A charged internal combustion engine according to claim 1 or 2, wherein the phase change material (4) absorbs heat during the phase change from the solid phase to the liquid phase.
4. a charged internal combustion engine according to claim 1, wherein the phase change material (4) releases heat during the phase change from the solid phase to the liquid phase.
5. A charged internal combustion engine according to any one of the preceding claims, wherein an exhaust gas recirculation arrangement is provided having a recirculation line to the intake system (1) forming a first junction upstream of the at least one compressor wheel (2 d).
6. A charged internal combustion engine according to any one of the preceding claims, wherein the at least one compressor (2) arranged in the intake system (1) belongs to an exhaust gas turbocharger comprising a turbine arranged in the exhaust gas discharge system and a compressor (2) arranged in the intake system (1).
7. The supercharged internal combustion engine of any one of the preceding claims, wherein the compressor (2) has an inlet region (2a), which inlet region (2a) extends coaxially with respect to the shaft of the compressor (2) and is designed such that the flow of pressurized air approaching the compressor (2) extends substantially axially.
8. A charged internal combustion engine according to claim 6 or 7, having an exhaust gas recirculation arrangement, wherein the recirculation line branches off from the exhaust gas discharge system, forming a second junction downstream of the turbine of the exhaust gas turbocharger.
9. A supercharged internal combustion engine as set forth in claim 8 wherein a first throttling element is disposed downstream of said second junction in said exhaust gas discharge system.
10. A charged internal combustion engine according to any one of claims 5 to 9, wherein in the intake system (1) a second throttle element is arranged upstream of the first junction.
11. A charged internal combustion engine according to claim 9 or 10, wherein the first and/or second throttling element is a pivotable flap.
12. A charged internal combustion engine according to any one of the preceding claims, wherein the compressor housing (2c) is equipped with a heating device upstream of the at least one compressor wheel (2 d).
13. A supercharged internal combustion engine according to claim 12, wherein the heating device comprises at least one electrically heatable wire integrated in the compressor housing (2 c).
14. a supercharged internal combustion engine according to claim 12, wherein the heating device comprises at least one duct arranged in the compressor housing (2c) and fillable with fluid.
15. A charged internal combustion engine according to claim 14, wherein the at least one conduit is connectable at least to the exhaust gas discharge system.
16. A charged internal combustion engine according to claim 14, wherein a liquid-type cooling device is provided, wherein the at least one conduit is connectable at least to the liquid-type cooling device.
17. A method of operating a supercharged internal combustion engine according to any one of the preceding claims, wherein during the phase change material (4) is activated in sequence to release heat for warming the compressor housing (2 c).
CN201910484660.4A 2018-06-11 2019-06-05 Supercharged internal combustion engine with a compressor and method for operating an internal combustion engine of said type Pending CN110578627A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102018209257.5 2018-06-11
DE102018209257 2018-06-11

Publications (1)

Publication Number Publication Date
CN110578627A true CN110578627A (en) 2019-12-17

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910484660.4A Pending CN110578627A (en) 2018-06-11 2019-06-05 Supercharged internal combustion engine with a compressor and method for operating an internal combustion engine of said type

Country Status (1)

Country Link
CN (1) CN110578627A (en)

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