DE102010048793B3 - Exhaust gas routing device for an internal combustion engine - Google Patents

Abstract

There are exhaust gas routing device for an internal combustion engine with an exhaust manifold (2) having a housing (7) in which at least one exhaust passage (10, 12), a plurality of exhaust gas inlets (4, 6), which are fluidically connected to exhaust passages of the crankcase and at least one exhaust gas outlet (14) are formed, an exhaust gas recirculation valve (30) which is arranged directly on the exhaust manifold (2) and at least one coolant channel, which is formed in the housing (7) of the exhaust manifold (2) known. However, recirculated exhaust gas must be additionally cooled in such exhaust manifolds to meet the emission levels. It is therefore proposed according to the invention that in the housing (7) of the exhaust manifold (2) a heat exchanger (42) is formed, the flow through the exhaust gas recirculation valve (30) is controllable, wherein the first exhaust gas outlet (14) of the exhaust manifold (2) upstream of the Heat exchanger (42) is arranged and a second exhaust gas outlet (62) of the exhaust manifold (2) downstream of the heat exchanger (42) is arranged. The result is an exhaust manifold with integrated exhaust gas cooler, which good cooling efficiencies are achieved with low installation costs and space.

Description

The invention relates to an exhaust gas routing device for an internal combustion engine having an exhaust manifold with a housing in which at least one exhaust duct, a plurality of exhaust gas inlets, which are fluidly connected to exhaust passages of a cylinder head or a crankcase and at least one exhaust outlet are formed, an exhaust gas recirculation valve, which is arranged directly on the exhaust manifold is and at least one coolant channel formed in the housing of the exhaust manifold.

Exhaust manifold for receiving the exhaust gas from the combustion chambers of the internal combustion engine are usually made of high temperature cast, such as gray cast iron, otherwise the maximum allowable thermal stress on the components would be exceeded. The known exhaust manifolds usually have one, two or three exhaust gas outlets, depending on whether the internal combustion engine is designed with or without a turbocharger and whether an exhaust gas recirculation directly uses the exhaust manifold as a branch or the exhaust gas recirculation branch is arranged only behind the exhaust manifold. In the case of branching off the exhaust manifold, an exhaust gas recirculation valve may be attached directly to the exhaust manifold housing. In the continuing exhaust pipe to the intake manifold, an exhaust gas cooler is usually arranged in modern internal combustion engines in order to be able to reduce the pollutant emissions in a known manner.

However, such known exhaust ducts have a high installation cost and space requirements. For this reason, in the DE 10 2007 053 126 A1 proposed an exhaust system in which in the exhaust manifold coolant channels are formed, which cool the exhaust manifold, so that its thermal load is reduced, whereby the exhaust manifold can be performed as a sheet metal part or aluminum casting. In addition, an exhaust gas recirculation cooler is completely dispensed with and the exhaust gas recirculation valve is flanged directly to the exhaust manifold. As a result, the required space and installation costs are reduced.

The disadvantage, however, is that the cooling effect to optimize pollutant emissions is often not high enough or too high an energy input into the coolant takes place, as this always cools the entire amount of exhaust gas regardless of the recirculated exhaust gas amount, which also leads to a lower efficiency of an optionally behind the exhaust manifold arranged turbocharger leads. The response time of an oxidation catalyst is prolonged by the longer warm-up time of the engine in this case.

It is therefore the object to provide an exhaust gas routing device with which not only the assembly costs and the required space are as small as possible, but in addition a good cooling efficiency for the recirculated exhaust gas is achieved, whereby pollutant emissions can be further reduced. Furthermore, it is desirable to provide the most accurate temperature control possible and to maintain turbocharger efficiency.

This object is achieved by the characterizing part of the main claim. Characterized in that in the housing of the exhaust manifold, a heat exchanger is formed, whose flow is regulated via the exhaust gas recirculation valve, wherein the first exhaust outlet of the exhaust manifold is disposed upstream of the heat exchanger and a second exhaust outlet of the exhaust manifold is disposed downstream of the heat exchanger, is achieved that within the housing the exhaust manifold and the regulation and cooling of the recirculated exhaust gas is realized. In particular, high cooling efficiencies for the recirculated exhaust gas can be achieved without having to use additional components. Cooling of the exhaust gas not returned to the intake manifold can be selectively performed or prevented. It creates a compact and easy to install unit.

Preferably, the coolant channel of the exhaust manifold forms a coolant jacket of the heat exchanger, so that no additional channels must be formed in the exhaust manifold. As a result, the production is simplified.

In an advantageous embodiment of the invention, the exhaust passage of the exhaust manifold arranged upstream of the exhaust gas recirculation valve and of the heat exchanger is at least partially surrounded by regions of the coolant jacket. In such an embodiment, the exhaust manifold can be made of a light metal casting instead of thermally resilient gray cast iron without being thermally overloaded due to the hot exhaust gas.

To minimize the space requirement and to simplify the arrangement of the coolant channels of the at least one exhaust passage and the heat exchanger are arranged substantially parallel to each other and at least partially flows through in the opposite direction.

Advantageously, the first exhaust gas outlet leads to a turbocharger and is designed to be double-flowed, wherein the first flow is connected to a first exhaust gas channel, which is fluidically connected to a first cylinder group and the second flow is connected to a second exhaust gas channel which is fluidically connected to a second cylinder group is wherein the first and the second exhaust passage are arranged parallel to each other and each having a connection to inlet chambers of the exhaust gas recirculation valve. This leads to favorable flow conditions in the exhaust manifold and in the flow of the turbocharger.

Preferably, the housing of the exhaust manifold is a light metal casting, thereby reducing weight, resulting in a fuel economy advantage.

In a further advantageous embodiment, a coolant valve is provided on the exhaust manifold, via which the coolant flow can be switched off. During a cold start of the internal combustion engine can be interrupted by means of this coolant valve, the coolant flow for faster heating of the internal combustion engine, resulting in a reduction of the resulting in the warm-up phase emissions result.

There is thus provided an exhaust gas routing device with which the pollutant emissions and the fuel consumption can be further reduced due to good cooler efficiencies and lower weights. At the same time the installation effort and the required space is minimized.

An embodiment of an exhaust gas routing device according to the invention is shown in the figures and will be described below.

1 shows a plan view of an exhaust gas routing device according to the invention in a perspective view.

2 shows a partially cutaway view of the exhaust gas routing device of the invention 1 in perspective view.

3 shows a cross section of the exhaust gas routing device according to the invention in a sectional view.

The exhaust gas routing device shown in the figures has an exhaust manifold 2 for a 6-cylinder engine, on which six exhaust gas inlets 4 . 6 are formed, which have flange surfaces 8th can be attached to a cylinder head for fluid carrying connection.

The exhaust gas inlets 4 . 6 are on a housing 7 the exhaust manifold 2 divided into two groups, the exhaust inlets 4 form the first group and into a first exhaust duct 10 in the case 7 the exhaust manifold 2 lead, which is parallel to a second exhaust passage 12 in the case 7 the exhaust manifold 2 is arranged, in which the second group of exhaust gas inlets 6 empties.

At the exhaust manifold 2 is a first double-flow outlet 14 trained, whose first tide 16 in flow communication with the first exhaust passage 10 stands and its second tide 18 in flow communication with the second exhaust passage 12 stands. This outlet 14 has a flange surface 20 on, over which the exhaust manifold 2 can be connected either directly or via pipelines to a turbine of a turbocharger.

The two exhaust channels 10 . 12 each have a passage 22 . 24 in two inlet chambers 26 a channel housing 28 an exhaust gas recirculation valve 30 on, of which an inlet chamber 26 in the 2 can be seen, and which on the housing 7 the exhaust manifold 2 is attached. The exhaust gas recirculation valve 30 is formed in the present embodiment as a flap valve, on the shaft 32 two valve bodies 36 arranged, each having an outlet of the inlet chambers 26 dominate. The wave 32 is in the duct housing 28 stored and protrudes for actuation through the channel housing 28 into an actuator 34 the exhaust gas recirculation valve 30 , Every valve body 36 gives one of the position of the actuator 34 or the wave 32 on which the valve body 36 are fixed, dependent flow area in the channel housing 28 free.

In the duct housing 28 the exhaust gas is deflected by 180 ° and flows back into the housing 7 the exhaust manifold 2 , which is parallel to the two exhaust channels 10 . 12 extends. In this area of the case 7 is a heat exchanger housing 38 arranged, which ribs 40 which extends into the interior of the heat exchanger housing 38 extend to improve the heat transfer. The heat exchanger housing 38 is surrounded by coolant, which flows between the heat exchanger housing 38 and the housing 7 the exhaust manifold 2 flows, leaving this part of the case 7 with the heat exchanger housing 38 a heat exchanger 42 forms, whose inner, exhaust gas flowed through channels from an outer coolant jacket 44 through the heat exchanger housing 38 is disconnected. One of these exhaust gas flowed through channels is in fluid communication with the first exhaust passage 10 over the first inlet chamber 26 while the other via the second, not shown chamber with the second exhaust passage 12 is in fluid communication.

The coolant jacket 44 extends in the present embodiment, in particular in 3 can be seen, even in areas 46 above and below the first and second exhaust ducts 10 . 12 so that they are also cooled by the coolant. This allows the formation of the exhaust manifold 2 for example, from light metal casting.

In addition, the coolant jacket extends 44 via a connection opening 47 in one in the outer area of the housing 7 arranged coolant channel 48 and from here into a channel housing 28 the exhaust gas recirculation valve 30 arranged coolant section 50 , whereby the channel housing 28 is also protected against overheating. Also an additional flow around the flap 36 via a coolant channel 52 in the surrounding channel housing 28 that with the coolant jacket 44 is in fluid communication, is executable, causing the actuator 34 additionally protected against thermal overload.

Downstream of the heat exchanger 42 is on the case 7 the exhaust manifold 2 a connection housing 54 an aftercooler 56 fastened, its inner casing 58 with the heat exchanger housing 38 connected is. The coolant jacket 44 of the heat exchanger 42 extends into the connector housing 54 so that the inner case 58 is also flowed around by coolant.

At the connection housing 54 of the aftercooler 56 is a tube housing 60 arranged, which has a second exhaust outlet 62 has, which is connected to the intake manifold of the internal combustion engine for the return of the exhaust gas. In the present embodiment is on this tube housing 60 an exhaust gas mass flow sensor 64 arranged for determining the recirculated exhaust gas flow. Furthermore, within the tube housing 60 Check valves arranged. Only behind the check valves is the separation of the two exhaust gas channels 10 . 12 , which is about the exhaust gas recirculation valve 30 and the heat exchanger 42 up to the check valves, canceled. Thus, pulsations in the exhaust system can be used to increase the exhaust gas recirculation rate.

Depending on the position of the flaps 36 will thus be in the exhaust manifold 2 flowing exhaust gas flow in appropriate proportions via the exhaust ducts 10 . 12 to the exhaust outlet 14 and from here to the turbocharger or via the exhaust gas recirculation valve 30 and the heat exchanger 42 to the second exhaust outlet 62 and from here to the suction pipe.

The described embodiment is easy to assemble as a unit and allows a space-reducing arrangement of the heat exchanger in the housing of the exhaust manifold, thereby eliminating lines. The flow through the exhaust manifold with the coolant leads both to an effective cooling of the exhaust manifold itself to make this from sheet metal or light metal and with the arrangement of the heat exchanger in the housing of the exhaust manifold to a high radiator efficiency in the exhaust gas recirculation.

It should be clear that the scope of the claims is not limited to the embodiment described, but various structural changes, in particular with respect to the arrangement of the channels to each other or the parting surfaces of the housing are conceivable. Of course, different types of exhaust gas recirculation valves can be used. In particular, a coolant valve can additionally be arranged for faster heating on the exhaust manifold, via which the coolant flow can be switched off.

Claims (7)

Exhaust gas routing device for an internal combustion engine with an exhaust manifold ( 2 ) with a housing ( 7 ), in which at least one exhaust duct ( 10 . 12 ), multiple exhaust inlets ( 4 . 6 ), which are fluidically connected to exhaust passages of a cylinder head or a crankcase and at least one exhaust gas outlet ( 14 ) are formed, an exhaust gas recirculation valve ( 30 ), which directly at the exhaust manifold ( 2 ) is arranged and at least one coolant channel in the housing ( 7 ) of the exhaust manifold ( 2 ), characterized in that in the housing ( 7 ) of the exhaust manifold ( 2 ) a heat exchanger ( 42 ) is formed, whose flow through the exhaust gas recirculation valve ( 30 ), wherein the first exhaust gas outlet ( 14 ) of the exhaust manifold ( 2 ) upstream of the heat exchanger ( 42 ) is arranged and a second exhaust outlet ( 62 ) of the exhaust manifold ( 2 ) downstream of the heat exchanger ( 42 ) is arranged. Exhaust gas routing device for an internal combustion engine according to claim 1, characterized in that the coolant channel of the exhaust manifold ( 2 ) a coolant jacket ( 44 ) of the heat exchanger ( 42 ). An exhaust gas routing device for an internal combustion engine according to any one of claim 2, characterized in that the at least one upstream of the exhaust gas recirculation valve ( 30 ) and the heat exchanger ( 42 ) arranged exhaust duct ( 10 . 12 ) of the exhaust manifold ( 2 ) at least partially of areas ( 46 ) of the coolant jacket ( 44 ) is surrounded. Exhaust gas routing device for an internal combustion engine according to any one of the preceding claims, characterized in that the at least one exhaust duct ( 10 . 12 ) and the heat exchanger ( 42 ) are arranged substantially parallel to each other and at least partially flowed through in the opposite direction. Exhaust gas routing device for an internal combustion engine according to one of the preceding claims, characterized in that the first exhaust gas outlet ( 14 ) leads to a turbocharger and is formed double-flow, wherein the first tide ( 16 ) with a first exhaust duct ( 10 ), which is fluidly connected to a first cylinder group and the second flood ( 18 ) with a second exhaust duct ( 12 ), which is fluidly connected to a second cylinder group, wherein the first and the second exhaust gas channel ( 10 . 12 ) are arranged parallel to each other and each have a passage ( 22 . 24 ) to inlet chambers ( 26 ) of the exhaust gas recirculation valve ( 30 ) exhibit. Exhaust gas routing device for an internal combustion engine according to one of the preceding claims, characterized in that the housing ( 7 ) of the exhaust manifold ( 2 ) is a light metal casting. Exhaust gas routing device for an internal combustion engine according to one of the preceding claims, characterized in that the exhaust manifold ( 2 ) A coolant valve is provided, via which the coolant flow can be switched off.

Images