DE102016102215B4 - Exhaust pipe system for a supercharged internal combustion engine - Google Patents

Abstract

Exhaust pipe system for a supercharged internal combustion engine with at least one turbocharger arranged in the exhaust pipe system (1), wherein a vaporizable liquid can be temporarily introduced into the exhaust pipe system (1), particularly in working phases of high power development of the internal combustion engine, in an area of the exhaust pipe system (1) in front of the turbocharger or turbochargers , wherein a cavity (5) is arranged for introducing the vaporizable liquid into the exhaust pipe system (1), characterized in that the cavity (5) encloses partial areas of the exhaust pipe system (1), and that in addition to feeding the vaporizable liquid into the cavity ( 5) in the exhaust pipe system (1) in front of the exhaust gas turbocharger, vaporizable liquid is introduced directly into the area of the exhaust pipe system (1) leading to the exhaust gas turbocharger.

Description

The invention relates to an exhaust pipe system for a supercharged internal combustion engine according to the preamble of patent claim 1 or 7 or 8.

Today's development trends in internal combustion engine construction - in particular so-called downsizing, combined with charging to increase the degree of filling of the combustion chambers of the internal combustion engine - make new charging concepts necessary to achieve high driving dynamics. The thermodynamic coupling of the internal combustion engine with its inconstant, possibly impulsive operation depending on driving conditions with an essentially continuously operating exhaust gas turbocharger may lead to a delayed pressure build-up in the exhaust gas turbocharger when starting up, in acceleration phases and in particular during rapid load changes and thus to what is usually referred to as a “turbo hole”. described undesirable effect. When the accelerator pedal is actuated in the direction of acceleration - in particular when the accelerator pedal is actuated with a high angular gradient, from which it can be concluded that there is a particularly high acceleration requirement - combustion air from the environment is fed into the exhaust pipe system and at the same time the amount of fuel is increased so that e.g. a rich combustion lambda (approx. 0.7 to 0.9) is created. The problem in these operating states is that significant changes in exhaust gas pressure and exhaust gas temperature can occur, which can lead to undesirable noise developments during operation of the internal combustion engine, and possibly even to long-term damage to components in the exhaust pipe system and/or possibly also to the exhaust gas turbocharger.

On the one hand, to control performance and, on the other hand, to avoid such undesirable side effects, a variety of solutions have become known from the prior art, including injecting water into the exhaust gas supply line to the exhaust gas turbocharger.

For example, in the DE 31 26 678 A1 an internal combustion engine is shown and described, in which water is injected into the exhaust manifold during acceleration phases to increase the power of an exhaust gas turbocharger. Through the evaporation of this water and the associated increase in the mass flow in the exhaust manifold, the speed of the exhaust gas turbocharger is increased and the boost pressure in the charge air line system of the internal combustion engine is thereby increased. With this solution, a faster increase in boost pressure is achieved, but a “turbo lag” still remains, since when the internal combustion engine accelerates from idle, the speed of the exhaust gas turbocharger does not increase suddenly, but only with acceleration and the water injection that begins is booted up.

In the DE 35 16 984 C2 A method is shown and described to resolve the problem identified above. For this purpose, water should be introduced into the exhaust system in addition to air and fuel in overrun mode, when idling and in lower partial load ranges of the internal combustion engine, so that a higher boost pressure is available before the throttle valve is actually opened when accelerating.

In the DE 34 21 355 A1 A further method for operating an internal combustion engine with an exhaust gas turbocharger is disclosed, in which water is injected into the area around the areas of the exhaust system that are at risk of overheating. The amount of water injected should be regulated via the boost pressure, oil pressure and/or engine speed. This direct injection of water into the exhaust system is not only intended to increase performance. Rather, relatively low speeds of the exhaust gas turbocharger and at the same time a cleaning effect of the turbine should be achieved.

Direct injection of water via an injector system into the exhaust pipe system of an internal combustion engine to increase performance is also possible JP 2008 008223 A shown and described.

DE 35 26 631 A1 discloses an exhaust pipe system for a supercharged internal combustion engine according to the preamble of patent claim 1 or 7 or 8.

The object of the present invention is to disclose an exhaust pipe system with an integrated exhaust gas turbocharger, in which the exhaust gas turbocharger can provide higher performance through additional mass flow and at the same time a harmful temperature increase in the exhaust gas flow is avoided particularly quickly.

This task is achieved by an exhaust pipe system according to patent claim 1, according to patent claim 7 and according to patent claim 8.

To introduce a vaporizable liquid into the exhaust pipe system, a cavity enclosing partial areas of the exhaust pipe system is arranged. This cavity in the exhaust pipe system, which is sealed off from the internal combustion engine, serves to evaporate the liquid introduced, in particular water. By the Evaporation of the liquid creates a volume increase in the vapor in the cavity of the exhaust pipe system many times over compared to the water introduced and thus a significant increase in pressure in the cavity of the exhaust pipe system. The steam can pass under high pressure from the cavity into the exhaust pipe system in the area near the exhaust gas turbocharger via a steam transfer opening. This reduces pressure and achieves the known effect of direct injection of water into the exhaust gas stream via the mixing effect of steam and exhaust gas stream. On the one hand, the additional mass flow of the exhaust gas turbocharger enables higher performance to be generated; On the other hand, the exhaust gas temperature can be sensibly controlled by the water introduced.

Depending on the amount of water available for introduction into the exhaust pipe system, significant fuel consumption savings can also be achieved in the high-speed range.

According to claim 1, in addition to the introduction of vaporizable liquid, for example water, into the cavity in the exhaust pipe system in front of the exhaust gas turbocharger, a vaporizable liquid, in particular water, is introduced, preferably injected, directly into the branch of the exhaust pipe system leading to the exhaust gas turbocharger. The direct introduction/injection of liquid/water preferably takes place in an area close to the turbocharger.

Water can preferably be used as the evaporable liquid. However, it is also conceivable that mixtures of water with detergents or anti-corrosion agents are used.

The introduction of the liquid can preferably be controlled depending on the respective accelerator pedal position via the management of the internal combustion engine. The injection preferably takes place via an injection valve or an injection nozzle. The duration and amount of introduction or injection of the liquid/water can preferably be controlled essentially as a function of the exhaust gas temperature.

The cavity of the exhaust pipe system can be sealed in a pressure-tight and vapor-tight manner relative to the internal combustion engine; it is only open to the exhaust pipe system in the main flow direction of the exhaust gas.

The cavity of the exhaust pipe system for introducing vaporizable liquid can essentially completely enclose exhaust gas-carrying areas of the exhaust pipe system. It expediently extends over a portion of the exhaust pipe system in an area close to the turbocharger.

According to claim 7, the cavity extends essentially over the entire exhaust gas collecting space in the exhaust pipe system.

According to claim 8, the vaporizable liquid/water is preferably introduced into the cavity via a component, preferably a valve or a nozzle. This component is arranged upstream of the exhaust gas in the cavity beginning area. The steam formed in the cavity is transferred via a steam transfer opening from the cavity into the exhaust pipe system and thus a pressure reduction downstream of the exhaust gas flow in the end region of the cavity in an area of the exhaust pipe system close to the turbocharger. This steam transfer opening essentially connects the cavity with the exhaust pipe system all around.

The liquid/water can be provided in any way. It is conceivable to pump out condensate in the end area of the exhaust pipe system (e.g. in or on a rear silencer); However, it is also conceivable that for a higher fluid requirement, a targeted generation of condensate is provided, for example by installing a heat exchanger in the area of, for example, the rear silencer of the exhaust pipe system.

Advantages, features and details of the subject matter of the invention also emerge from the following description of a preferred exemplary embodiment and from the schematic drawing.

The features and combinations of features mentioned above in the description as well as the features and combinations of features shown below in the figures of the drawing and described below with reference to the drawing can be used not only in the combination specified in each case, but also in other combinations or on their own, without the scope of the To hereby abandon the invention.

• 1 einen Abgassammelraum eines Abgasleitungssystems für eine aufgeladene Brennkraftmaschine nach der Erfindung und
• 2 eine schematische Darstellung des Abgassammelraums nach 1.

It shows:

• 1 an exhaust gas collecting chamber of an exhaust pipe system for a supercharged internal combustion engine according to the invention and
• 2 a schematic representation of the exhaust gas collection room 1 .

In the exhaust pipe system 1 of a supercharged internal combustion engine, the gas escaping from the combustion chambers is collected via their exhaust valves tending exhaust gas, an exhaust gas collecting chamber 2 is arranged to bring together the exhaust gas lines from the individual combustion chambers. Hot exhaust gas is supplied to this exhaust gas collecting chamber 2 via the exhaust gas inlet opening 3. On the end side of the exhaust gas collecting chamber 2 opposite the exhaust gas inlet opening 3, an exhaust gas turbocharger (not shown here) is arranged, via whose compressor wheel charged fresh air is in turn supplied to the combustion chambers. In the exemplary embodiment shown, the exhaust gas collecting chamber 2 is essentially double-walled (sectional view). Due to the retracted wall 4 arranged all around, a cavity 5 is formed in the exhaust gas collecting chamber 2 essentially over its entire extent. A vaporizable liquid, for example water, is fed, for example injected, into the cavity 5 via the component 6 (valve/nozzle) arranged upstream of the exhaust gas in the cavity beginning region. As a result of the temperature difference between the liquid fed in and the exhaust gas flowing in the interior of the exhaust gas collecting chamber 2 in the direction of the exhaust gas turbocharger, the liquid/water evaporates. As a result of the associated increase in volume, a significant increase in pressure initially occurs in the cavity 5. The pressurized steam enters the exhaust gas stream in the transition area to the exhaust gas turbocharger via a steam transfer opening 7. The steam transfer opening 7 can be arranged all around, preferably in the transition area to the exhaust gas turbocharger at the end of the exhaust gas collecting chamber 2.

In addition to the liquid feed via the component 6 into the initial area of the cavity 5 in the exhaust gas collecting space 2, an additional component 8 (see 1 ) can be arranged for direct feeding of liquid to be evaporated into the exhaust gas stream. The component 8 can also be located upstream of the exhaust gas (see 2 ) to be ordered.

By feeding vaporizable liquid/water indirectly into a cavity 5 in the exhaust pipe system 1 or in the exhaust gas collecting chamber 2, the exhaust gas temperature can be regulated sensitively via the management of the internal combustion engine. This serves to protect the components. At the same time, it can be achieved that higher power can be delivered via the exhaust gas turbocharger due to the additional mass flow. This additional mass flow can also be used at relatively low speeds to completely or partially avoid the so-called “turbo lag”.

The provision of the evaporable liquid or the provision of water can be achieved in various ways. It is conceivable, for example, to collect or pump out condensate that forms in the end area of the exhaust pipe system (e.g. in the rear silencer). By installing a heat exchanger in this end region of the exhaust pipe system, it is even conceivable to generate additional amounts of condensate, which is then used for injection over longer phases. However, it is also conceivable that the manageable fluid requirement is made available via a reservoir assigned to the internal combustion engine.

Reference symbol list

1

Exhaust pipe system

2

Exhaust gas collection room

3

Exhaust gas inlet opening

4

all-round wall

5

cavity

6

Component (valve/nozzle)

7

Steam transfer opening

8th

Component

Claims (11)

Exhaust pipe system for a supercharged internal combustion engine with at least one turbocharger arranged in the exhaust pipe system (1), wherein a vaporizable liquid can be temporarily introduced into the exhaust pipe system (1), particularly in working phases of high power development of the internal combustion engine, in an area of the exhaust pipe system (1) in front of the turbocharger or turbochargers , wherein a cavity (5) is arranged for introducing the vaporizable liquid into the exhaust pipe system (1), characterized in that the cavity (5) encloses partial areas of the exhaust pipe system (1), and that in addition to feeding the vaporizable liquid into the cavity ( 5) in the exhaust pipe system (1) in front of the exhaust gas turbocharger, vaporizable liquid is introduced directly into the area of the exhaust pipe system (1) leading to the exhaust gas turbocharger. Exhaust pipe system Claim 1 , characterized in that water can be used as the vaporizable liquid. Exhaust pipe system Claim 1 , characterized in that depending on the respective accelerator pedal position, the time and amount of liquid that can be introduced into the cavity (5) is controlled or regulated via the internal combustion engine management. Exhaust pipe system Claim 1 or. Claim 3 , characterized in that the duration and amount of introduction of the liquid can be controlled or regulated essentially as a function of the exhaust gas temperature in the exhaust pipe system (1). Exhaust pipe system Claim 1 , characterized in that the cavity (5) with a steam transfer opening (7) is only open towards the exhaust pipe system (1) and is arranged sealed from the internal combustion engine. Exhaust pipe system according to one of the preceding claims, characterized in that the direct introduction/injection takes place in a region of the exhaust pipe system (1) close to the turbocharger. Exhaust pipe system for a supercharged internal combustion engine with at least one turbocharger arranged in the exhaust pipe system (1), wherein a vaporizable liquid can be temporarily introduced into the exhaust pipe system (1), particularly in working phases of high power development of the internal combustion engine, in an area of the exhaust pipe system (1) in front of the turbocharger or turbochargers , wherein a cavity (5) is arranged for introducing the vaporizable liquid into the exhaust pipe system (1), characterized in that the cavity (5) encloses partial areas of the exhaust pipe system (1), and that the cavity (5) within one in the exhaust pipe system ( 1) arranged exhaust gas collecting chamber (2) which extends essentially over its entire longitudinal extent. Exhaust pipe system for a supercharged internal combustion engine with at least one turbocharger arranged in the exhaust pipe system (1), wherein a vaporizable liquid can be temporarily introduced into the exhaust pipe system (1), particularly in working phases of high power development of the internal combustion engine, in an area of the exhaust pipe system (1) in front of the turbocharger or turbochargers , wherein a cavity (5) is arranged for introducing the evaporable liquid into the exhaust pipe system (1), characterized in that the cavity (5) encloses partial areas of the exhaust pipe system (1), that the component introducing the evaporation liquid into the cavity (5). (6) upstream of the exhaust gas in the initial region of the cavity (5) and a steam transfer opening (7) from the cavity (5) into the exhaust pipe system (1) is arranged downstream of the exhaust gas in the end region of the cavity (5) in an area close to the turbocharger, and that the steam transfer opening ( 7) connects the cavity (5) with the exhaust pipe system (1) essentially all around in an area close to the turbocharger. Exhaust pipe system Claim 8 , characterized in that the component (6) introducing the evaporation liquid into the cavity (5) is a valve or a nozzle. Exhaust gas line system according to one of the preceding claims, characterized in that the liquid that can be introduced is used as condensate from the exhaust gas line system (1) by pumping it out. Exhaust pipe system according to one of the preceding claims, characterized in that the exhaust pipe system (1) is used in a supercharged internal combustion engine for a motor vehicle.

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