EP1522701A1 - Multicylinder internal combustion engine and method for cylinder cut-off - Google Patents

Abstract

Multiple cylinder internal combustion engine (1) comprises a first lambda probe (11) and a first catalyst (12) arranged in a first exhaust gas pipe (8), a second lambda probe (13) and a second catalyst arranged in a second exhaust gas pipe (9), and a common controlled throttle valve (6) arranged in the inlet region (4) of the cylinders (A-D). Both exhaust gas pipes open into a complete exhaust gas pipe (10). An independent claim is also included for a process for partially switching off the multiple cylinder internal combustion engine. Preferred Features: A third catalyst is arranged in the complete exhaust gas pipe or in the second exhaust gas pipe behind the second lambda probe. The controlled throttle valve is an electronically controlled throttle valve.

Description

The invention relates to a multi-cylinder internal combustion engine with a lambda probe, a catalyst and having a first group of cylinders and a second group of cylinders, each comprising at least one cylinder and of which the second group of cylinders can be switched off in the partial load range, the first group of cylinders having a separate first exhaust pipe and the second group of cylinders equipped with a separate second exhaust pipe is.

Furthermore, the invention relates to a method for partial shutdown of a such multi-cylinder internal combustion engine.

Due to the limited resources of fossil fuels, in particular due to the limited reserves of mineral oil as a raw material for extraction of fuels for the operation of internal combustion engines, one is at the Development of internal combustion engines constantly strives to increase fuel economy minimize, with an improved d. H. more effective combustion in the foreground the effort stands.

The problem is the fuel consumption and thus the efficiency in particular in gasoline engines. The reason for this lies in the principle working method of the Otto engine. The Otto engine works with a homogeneous fuel-air mixture, that - if there is no direct injection - by external mixture formation is prepared by introduced into the intake air in the intake tract fuel becomes. The desired power is set by changing the Filling the combustion chamber, so that the working method of the gasoline engine - unlike diesel engine - a quantity regulation is based.

This load control is usually carried out by means provided in the intake Throttle. By adjusting the throttle, the pressure of the sucked Air behind the throttle will be reduced more or less severely. The further the Throttle is closed d. H. the more it blocks the intake tract the more higher is the pressure loss of the intake air across the throttle and the lower the pressure of the intake air behind the throttle and before the inlet to the combustion chamber. With constant combustion chamber volume can on this About the pressure of the intake air, the air mass d. H. the quantity be set. This also explains why this type of quantity regulation especially in the partial load range proves to be disadvantageous because low loads require one high throttling and pressure reduction in the intake tract, causing the Charge exchange losses with decreasing load and increasing throttling increase, which is briefly explained below.

The quantity regulation by means of throttle valve has thermodynamic disadvantages. Due to the pressure reduction of the sucked air of the four-cycle cycle comprehensive thermodynamically adversely affected, since by the throttling of the internal medium pressure p _mi due to the reduced pressure of the sucked air and the associated larger charge exchange losses decreases. Together with the stroke volume V _h , the internal mean pressure p _mi gives the work won per working cycle W _A. The following applies: p Wed. * V H = ∫ p dV-W A

Further considerable losses in efficiency result from wall heat losses Q due to the heat transfer from the combustion gases to the Combustion chamber walls in the combustion chamber.

To the losses described - the throttle losses on the one hand and the Heat transfer losses on the other hand - to lower, were different strategies developed for load control, which are found in the prior art.

Due to the fact that the gasoline engine by the principle Throttling control in the partial load range high charge exchange losses with the resulting resulting relatively poor partial load efficiencies occur and on the other hand In the diesel engine, the quality control to a relatively good efficiency in the Part load range and thus leads to a favorable fuel consumption, were Early on attempts were made to correlate both working methods combine.

One approach to prior art de-throttling is For example, an Otto engine work with stratified Combustion chamber charge. The direct injection of the fuel can be a be suitable means for the realization of the stratified combustion chamber charge. The Direct injection of the fuel into the combustion chamber leads in addition to avoidance of throttling losses also to a reduction in heat losses, as the Flame moving in the combustion chamber with its unfavorably high Heat transfer meets only a small part of the combustion chamber inner wall.

Another way to optimize the combustion process of a gasoline engine, consists in the use of a variable valve train. In contrast to conventional valve trains, in which both the stroke of the valves and the Control times, i. the opening and closing times of the intake and exhaust valves, due to the non-flexible, as not adjustable mechanism of the valve train as immutable variables are given, these can be the combustion process and thus the parameter influencing the fuel consumption by means of variable Valve gears are more or less varied. The ideal solution would be one fully variable valve timing, which is suitable for any operating point of the gasoline engine Specially tuned values for the stroke and the timing allow.

Noticeable fuel savings can also be achieved with only partially variable fuel Valve drives are achieved. Such a valve train is for example the VALVETRONIC Valve Train from BMW, as described in the Motortechnische Zeitung, Vintage 2001, No. 6, page 18 is described.

In this valve train, the closing timing of the intake valve and the intake valve lift can be varied. As a result, a throttle-free and thus lossless load control is possible.
The mixture mass flowing into the combustion chamber during the intake process is not controlled as in conventional gasoline engines by means of a throttle valve arranged in the intake tract, but is dimensioned via the intake valve stroke and the opening duration of the intake valve.

A variable valve train was also recognized by Porsche as a solution and realized with the VarioCam Plus.

The concepts shown invariably have the disadvantage that they are not are universally applicable, since they are essential changes to the basic engine or the Valve gear and require additional complex components. Consequently, they can only at future generations of engines will be considered, since they are not for one Retrofitting already in circulation engines are suitable. A concept for De-throttling of equipped with throttle valves gasoline engines, which also at will be applied in the market already in the market State of the art not shown.

Although in principle the efficiency in the partial load range by the Shutdown of one or more cylinders improves d. H. increase. Because the Shutdown of some cylinders of the multi-cylinder internal combustion engine increases the Load the operating cylinder so that the throttle continues can be opened or must, causing a Entdrosselung the multi-cylinder internal combustion engine is reached.

In the prior art but only internal combustion engines and Described method in which the partial shutdown by a full Shut off the cylinder to be shut down. Ie. the cylinders become switched off by both the supply of combustion air and the supply of Fuel is prevented. This is a complete redesign of the intake system conventional internal combustion engines required, which is why this Solution for Entdrosselung only conditionally for retrofitting already on the Market available engines.

Namely, the intake tract must be modified in such a way that the constantly in Operating cylinder and deactivatable cylinder via separate Intake ducts have. In addition, must be in the intake of the disconnectable Cylinders are provided a shut-off with which the supply of Combustion air or fuel / air mixture in the context of partial shutdown controlled d. H. can be blocked or released.

An internal combustion engine of the type in question and a method for Partial shutdown of such an internal combustion engine discloses the German Publication DE 33 05 704 A1 using the example of a six-cylinder in-line engine, this font is not the partial shutdown as such but a Precise control of exhaust gas recirculation ratio over the whole Operating range of the engine to reduce harmful emissions.

DE 33 05 704 A1 describes a multi-cylinder internal combustion engine generic type comprising a controller comprising a number of Cylinders by putting them out of service under operating conditions low load the flow of the air / fuel mixture to the out of service locked cylinders locks. For this purpose, the intake manifold is in two intake ports divided, of which the first intake manifold to the constantly in operation located cylinders and the second intake to the turn-off cylinders leads. In addition, the second intake port has a shut-off valve in shape a second throttle with which this second exhaust passage is released or closed can be disabled for the purpose of partial shutdown.

The intake of this multi-cylinder internal combustion engine is with a conventional intake tract is no longer comparable and can not be easier Be prepared by modification of such an intake tract.

Against this background, it is the object of the present invention To provide multi-cylinder internal combustion engine, which via a partial shutdown for Entdrosselung the internal combustion engine features, with which the state of the Technique known disadvantages are overcome, the partial shutdown in particular of the kind that only a slight modification of conventional Internal combustion engine is required

Another subtask of the present invention is a simple method for partial shutdown and thus for de-throttling such a multi-cylinder internal combustion engine show, with the state of the art known disadvantages are overcome, and in particular a retrofit permitted by existing on the market conventional internal combustion engines.

• die Lambda-Sonde und der Katalysator im ersten Abgasrohr angeordnet sind,
• eine zweite Lambda-Sonde und ein zweiter Katalysator vorgesehen sind, wobei die zweite Lambda-Sonde und der zweite Katalysator im zweiten Abgasrohr oder, wenn beide Abgasrohre in ein Gesamtabgasrohr münden, die zweite Lambda-Sonde im zweiten Abgasrohr und der zweite Katalysator in diesem Gesamtabgasrohr angeordnet sind, und
• im Einlaßbereich der Zylinder nur eine gemeinsame, regelbare Drosselklappe angeordnet ist, mit der die Menge an Verbrennungsluft, mit der die Zylinder beaufschlagt werden, dosiert wird, wobei die zweite Gruppe von Zylindern im Teillastbereich dadurch abgeschaltet wird, daß die Kraftstoffzufuhr zu diesen Zylindern unterbunden wird.

The first sub-task is solved by a multi-cylinder internal combustion engine with a lambda probe, a catalyst and a first group of cylinders and a second group of cylinders, each comprising at least one cylinder and of which the second group of cylinders in the partial load range can be switched off is, wherein the first group of cylinders with a separate first exhaust pipe and the second group of cylinders is equipped with a separate second exhaust pipe, and which is characterized in that

• the lambda probe and the catalyst are arranged in the first exhaust pipe,
• a second lambda probe and a second catalyst are provided, wherein the second lambda probe and the second catalyst in the second exhaust pipe or, if both exhaust pipes open into an overall exhaust pipe, the second lambda probe in the second exhaust pipe and the second catalyst in this total exhaust pipe are arranged, and
• in the inlet region of the cylinder only a common, controllable throttle valve is arranged, with which the amount of combustion air, with which the cylinders are acted upon, is switched off, wherein the second group of cylinders in the partial load range is switched off by the fact that the fuel supply to these cylinders is inhibited ,

By means of the multi-cylinder internal combustion engine according to the invention, the thermodynamic disadvantages i. the charge cycle losses, which are due to the quantity control by means of throttle flap, be attenuated. in the Partial load range, a second group of cylinders can be switched off, whereby the load of the first group of cylinders increases, causing an opening of the cylinder Throttle and thus a Entdrosselung the internal combustion engine allowed.

In this case, according to the invention, the partial shutdown takes place in an advantageous manner, that only the fuel supply to the cylinders of the second group prevented becomes, whereby these are put out of operation in such a way that although the aspirated combustion air still flows through the deactivated cylinders, but due to the lack of fuel input no combustion in these cylinders takes place.

The second group of cylinders does not contribute during the partial shutdown Power output of the internal combustion engine at. On the contrary, that the Fresh air not - as described in the prior art - is saved, but The cylinders of the second group continue to pass, taking this air to the four Work cycles - suction, compression, expansion and ejection - continue Part, so that the deactivated cylinders not only do not work, but rather work for the charge change must be invested in this cylinder.

The main advantage of the internal combustion engine according to the invention is to see that in contrast to that described in DE 33 05 704 A1 Internal combustion engine, the turn-off cylinder of the second group Partial shutdown need not be completely isolated in the way that this Cylinder by means of a shut-off valve from the supply of combustion air or Fresh mixture to be cut off. Consequently, the invention requires Internal combustion engine not only no shut-off valve. The intake tract must not be in be modified the type that the constantly operating cylinder of the first Group and the deactivatable cylinders of the second group via separate Intake ducts have.

In other words; the internal combustion engine according to the present Invention may be with a conventional intake system or intake equipment, which lowers the development costs and the other the proposed concept of a partial shutdown also for retrofitting already on the market located internal combustion engines appear to be suitable. The intake tract need only be equipped with a throttle valve, which in a closed-loop method is controllable, wherein a throttle valve in principle already exists.

An advantage of the controllable throttle is that when activating or Deactivating the partial shutdown i.e.. the torque of the engine does not fall or increases and the driver does not need to track the gas pedal to hold the load which would be the case with non-controllable throttle.

Due to the principle of the partial disconnection according to the invention underlying principle, namely, the partial shutdown only by blocking the fuel supply Undisturbed promotion of the combustion air to realize are certain Modifications of the exhaust tract required. But these modifications can be made in Type and scope not with those known from the prior art, above described modifications of the intake tract to be compared.

In this case, the first group of cylinders with a separate first exhaust pipe and the second group of cylinders with a separate second exhaust pipe equipped, with both exhaust pipes combined to form an overall exhaust pipe can be. Such a design of the exhaust tract is but after the The prior art partly already common and results from the fact that the outlets the cylinder have separate exhaust manifold, which then gradually be merged. For example, a so-called four-in-two-in-one exhaust manifold for a four-cylinder inline engine quite common.

According to the invention, the lambda probe and the catalyst in the first Exhaust pipe arranged. This first catalyst is used exclusively for Conversion of the cylinders in operation from the first in operation Group exhaust gases and is independent of the operating state of the Internal combustion engine neither of the exhaust gases of the deactivatable cylinder of the second Group still from the case of partial shutdown disabled by these cylinders guided air is applied.

For this reason, in addition a second lambda probe and a second Catalyst provided, this second lambda probe and this second Catalyst in the second exhaust pipe or, if both exhaust pipes in one Entire exhaust pipe open, the second lambda probe in the second exhaust pipe and the second catalyst are arranged in this entire exhaust pipe.

The two variants are within the scope of the description of the preferred Embodiments and explained in more detail in the description of the figures. Both have the goal that the effluent from the cylinders of the second group Exhaust gases flow through a catalyst and are converted.

As stated in detail, with the inventive multi-cylinder internal combustion engine an internal combustion engine provided via a Partial shutdown for Entdrosselung the internal combustion engine has, with which the overcome the known disadvantages of the prior art, wherein the Partial shutdown in particular of the kind that only a slight modification conventional internal combustion engines with correspondingly little additional components and costs is required. Thus, the first of the invention is based Task solved.

In multi-cylinder internal combustion engines, in which the second lambda probe and the second catalyst are arranged in the second exhaust pipe and the two exhaust pipes lead into an overall exhaust pipe, embodiments are advantageous thereby are characterized in that a third catalyst is provided, wherein the third Catalyst is arranged in the entire exhaust pipe.

In multi-cylinder internal combustion engines, in which the second lambda probe in second exhaust pipe and the second catalyst is disposed in the overall exhaust pipe, embodiments are advantageous, which are characterized in that a third Catalyst is provided, wherein the third catalyst in the second exhaust pipe behind the second lambda probe is arranged.

According to these embodiments, when the partial shutdown is deactivated, the two exhaust gas flows of the two cylinder groups each in a separate in the First and second exhaust pipe arranged catalyst a Exhaust gas aftertreatment subjected. Then they are mixed and together fed to another catalyst in which again a Exhaust gas aftertreatment occurs. An advantage of this embodiment is that the two gas flows of the two groups of cylinders also at Teilabschaltung too a total exhaust gas flow are combined and then a go through further provided in the entire exhaust pipe catalyst.

In the latter variant, the gas flow is the second Group of cylinders to a pure air flow, the actual exhaust gas flow the first group after the first and before the second after treatment similar to is supplied in a secondary air injection. The extra oxygen can be used for a further oxidation of the pollutants, in particular the oxidation of unburned hydrocarbons (HC) and carbon monoxide (CO), in Serve the exhaust tract.

Since relatively high temperatures are required for HC and CO oxidation especially the concentrations of these pollutants, especially after a cold start and in the partial load range, ie at a low operating temperature of Internal combustion engine, high, which is why the latter embodiments of the Internal combustion engine, in particular when operating at low temperatures than prove beneficial. On the one hand, the partial shutdown of the second group of cylinders the load of the remaining cylinders and thus the operating temperature of the Internal combustion engine increased. On the other serves for secondary air injection of Air flow, which was passed through the deactivated cylinder, and thus one preheated air flow, the HC and CO oxidation in an advantageous manner supported.

Advantageous embodiments of the multi-cylinder internal combustion engine, in which the throttle is an electronically controlled throttle. This is advantageous Embodiment, because the electronics basically reinforced in engine construction for Application comes and therefore often an electronically controlled throttle already exists. Furthermore, an existing engine control take over the regulation of such a throttle.

Advantageous embodiments of the multi-cylinder internal combustion engine, in which behind the built-in catalysts in each case a further lambda probe is provided so that an extended on-board diagnosis is feasible. The on-board diagnosis was used as a control of the emission behavior of one in circulation located motor vehicle introduced. Initially, emission-relevant Monitored components of the engine control and the like. Later was one Extension of the monitored components Aim of the effort. So is according to the preferred embodiment of the internal combustion engine monitoring the Lambda probe and the catalyst possible, with a display and Storage of the collected data and access to this data provided can be.

Advantageous embodiments of the multi-cylinder internal combustion engine, in which the multi-cylinder internal combustion engine is a four-cylinder internal combustion engine. It must be taken into account that there is a trend towards small, has completed supercharged engines and continues to perform. It is the Charging primarily a method of increasing performance, in which the for the engine combustion process compressed air is compressed so that per Working cycle a larger air mass enters the combustion chamber. This allows the Fuel mass can be increased. With targeted design of the charge can also advantages in the efficiency and in the exhaust emissions can be achieved. One typical representative of the small, supercharged engines is a gasoline engine with Exhaust gas turbocharging, in which the exhaust gas energy for compression of the Combustion air is used.

By means of the inventive principle of partial shutdown, could a Teilabschaltung also done with these engines, without the benefits of Charge would have to be waived. For supercharged engines, the at operated according to high temperatures, the Partial shutdown especially advantageous because of the effect, because the Reduction of heat loss resulting from heat transfer from Brennrauminneren on the combustion chamber walls, here due to the high Operating temperatures would be particularly clear. Here is the reduction the Wandwärmverluste by reducing the combustion chamber surfaces due Partial shutdown a fundamental advantage of this principle of de-throttling.

Advantageous embodiments of the multi-cylinder internal combustion engine, in which the multi-cylinder internal combustion engine is an in-line engine, preferably either the first group of cylinders the two inner and the second group of cylinders comprising the two outer cylinders or the first group of Cylinders the two outer and the second group of cylinders the two inner cylinder covers. This is advantageous because, on the one hand, the first and the fourth piston and on the other hand the second and the third piston the same Perform movement, which is why a merger of these pistons to appropriate groups is to be preferred.

• im Einlaßbereich der Zylinder lediglich eine gemeinsame, regelbare Drosselklappe angeordnet wird, mit der die Menge an Verbrennungsluft, mit der die Zylinder beaufschlagt werden, dosiert wird,
• die zweite Gruppe von Zylindern im Teillastbereich dadurch abgeschaltet wird, daß die Kraftstoffzufuhr zu diesen Zylindern unterbunden wird,
• die Lambda-Sonde und der Katalysator im ersten Abgasrohr angeordnet werden,
• eine zweite Lambda-Sonde und ein zweiter Katalysator vorgesehen werden, wobei die zweite Lambda-Sonde und der zweite Katalysator im zweiten Abgasrohr oder, wenn beide Abgasrohre in ein Gesamtabgasrohr münden, die zweite Lambda-Sonde im zweiten Abgasrohr und der zweite Katalysator in diesem Gesamtabgasrohr angeordnet werden.

The second partial object of the present invention is achieved by a method for partial shutdown of a multi-cylinder internal combustion engine of the generic type, which is characterized in that

• in the inlet region of the cylinder only a common, controllable throttle valve is arranged, with which the amount of combustion air, with which the cylinders are acted upon, is metered,
• the second group of cylinders is switched off in the partial load range by stopping the supply of fuel to these cylinders,
• the lambda probe and the catalyst are arranged in the first exhaust pipe,
• a second lambda probe and a second catalyst are provided, wherein the second lambda probe and the second catalyst in the second exhaust pipe or, if both exhaust pipes open into an overall exhaust pipe, the second lambda probe in the second exhaust pipe and the second catalyst in this total exhaust pipe to be ordered.

The method according to the invention deactivates the second group of cylinders, by the fuel supply is prevented, without the air supply to the shut down cylinders needs to be prevented by means of shut-off elements. It This is not necessary, the deactivated cylinders when partial shutdown completely too isolate or disable the valve actuator of these cylinders put. The basic principle of the method is that even with partial shutdown the Supply of deactivated cylinders is maintained with fresh air.

In the partial load range, a second group of cylinders is switched off, causing the Load of the remaining in-service cylinder is increased, so that the Throttle valve must be opened further. This is the invention Method a method for Entdrosselung an internal combustion engine.

In contrast to conventional methods, the invention requires Procedure no complex modification of the intake system, but only the Use of a second lambda probe and a second catalyst.

In multi-cylinder internal combustion engines, in which the second lambda probe and the second catalyst are arranged in the second exhaust pipe and the two Exhaust pipes open into an overall exhaust pipe are embodiments of the Method for partial shutdown advantageous in which a third catalyst is provided, wherein the third catalyst is disposed in the entire exhaust pipe.

In multi-cylinder internal combustion engines, in which the second lambda probe in second exhaust pipe and the second catalyst disposed in the entire exhaust pipe Embodiments of the method for partial shutdown are advantageous in where a third catalyst is provided, the third catalyst being in the second exhaust pipe is disposed behind the second lambda probe.

The advantages of the last two embodiments have already been mentioned Connection with the internal combustion engine according to the invention explains why At this point, reference should be made to these statements. In particular, the post-oxidation of unburned hydrocarbons (HC) and Carbon monoxide (CO) during the partial shutdown operation of the Internal combustion engine by supplying the deactivated by the cylinder Promoted air in the total exhaust pipe is to be regarded as advantageous.

Advantageous embodiments of the method for partial shutdown, in which used as an adjustable throttle an electronically controlled throttle is because the use of electronically controlled throttle is already widespread and continues to increase and this type of regulation over an already existing Motor control can be done so that no additional control device must be provided. This embodiment is therefore also with regard to Costs to be preferred.

Advantageous embodiments of the method for partial shutdown, in which behind the built-in catalysts in each case a further lambda probe is provided to perform an advanced on-board diagnostic (OBD) can.

For partial shutdown of a four-cylinder in-line engine are embodiments of Method advantageous in which the first group of cylinders, the two inner and the second group of cylinders comprises the two outer cylinders such that a partial shutdown of the internal combustion engine by switching off the two outer Cylinder takes place, embodiments of the method are also advantageous, where the first group of cylinders are the two outer and the second group of cylinders comprising the two inner cylinders, so that a partial shutdown of Internal combustion engine is done by switching off the two inner cylinder.

Fig. 1

schematisch eine erste Ausführungsform der Mehrzylinder-Brennkraftmaschine,

Fig. 2

schematisch eine zweite Ausführungsform der Mehrzylinder-Brennkraftmaschine, und

Fig. 3

schematisch eine dritte Ausführungsform der Mehrzylinder-Brennkraftmaschine.

In the following the invention with reference to three embodiments according to Figures 1, 2 and 3 will be described in more detail. Hereby shows:

Fig. 1

schematically a first embodiment of the multi-cylinder internal combustion engine,

Fig. 2

schematically a second embodiment of the multi-cylinder internal combustion engine, and

Fig. 3

schematically a third embodiment of the multi-cylinder internal combustion engine.

Figure 1 shows schematically a first embodiment of the multi-cylinder internal combustion engine 1. This is an in-line engine 1 with four cylinders A, B, C, D.

The four cylinders A, B, C, D of the multi-cylinder internal combustion engine 1 are in two Groups 2.3 of cylinders A, B, C, D divided. The first group 2 of cylinders comprises the two inner cylinders B, C of the multi-cylinder internal combustion engine 1, whereas the second group 3 of cylinders has the two outer cylinders A, D includes. In the embodiment shown in Figure 1, the Partial shutdown of the multi-cylinder internal combustion engine 1 by switching off the second group 3 of cylinders i. by switching off the two outer cylinders A, D, which will be described in more detail below.

All four cylinders A, B, C, D have a common plenum 5 and one common, electronically controlled throttle 6 in the inlet area 4, with the is regulated by the four cylinders A, B, C, D sucked air quantity. The Internal combustion engine 1 may be due to the partial shutdown underlying Principle, namely the partial shutdown only by blocking the To realize fuel supply with undisturbed promotion of combustion air, with a conventional intake 4 and only one controllable throttle 6 equipped become. An elaborate redesign or redesign of the intake tract - as in the known and described in the prior art Partial shutdown - is not required.

There are only minor modifications of the exhaust system 7 perform the are justified by the fact that even at partial shutdown continues to air through the shut off cylinder A, D is promoted. These modifications can be found in Art and scope not with the known from the prior art modifications of Intake tract are compared.

For this purpose, the first group 2 of cylinders B, C with a separate first Exhaust pipe 8 and the second group 3 of cylinders A, D with a separate equipped second exhaust pipe 9, wherein both exhaust pipes 8,9 in a Total exhaust pipe 10 open, i. to a common exhaust pipe 10th be merged. Thus, the exhaust tract 7 is a so-called four-in-two-in-one exhaust manifold educated.

The first lambda probe 11 and the first catalyst 12 are basically in first exhaust pipe 8 arranged because the exhaust gases of the constantly operating Cylinder B, C of the first group of cylinders 2 in this first exhaust pipe. 8 be initiated. In this way is an exhaust aftertreatment of the exhaust gases this constantly operating cylinder B, C guaranteed.

There are further a second lambda probe 13 and a second catalyst 14 provided, wherein the second lambda probe 13 in the second exhaust pipe 9 and the second catalyst 14 are arranged in the entire exhaust pipe 10.

According to these embodiments, when partial deactivation is deactivated, the two exhaust gas streams of the two cylinder groups 2,3 aftertreated in the way that the exhaust flow of the first group 2 of cylinders B, C in the separate, in the first Exhaust pipe 8 arranged catalyst 12 subjected to exhaust aftertreatment becomes. Subsequently, the exhaust gas flow of the second group 3 of cylinders A, D with the already aftertreated exhaust stream of the first group 2 of cylinders B, C mixed and fed together to a second catalyst 14, in which another exhaust aftertreatment takes place.

But advantageous in this embodiment is in particular the interaction the gas flows with activated partial shutdown. Because the two gas streams of the two Groups 2,3 of cylinders A, B, C, D become a partial shutdown to a Combined total exhaust gas flow and then go through another, provided in the total exhaust pipe 10 catalyst 14th

When partial shutdown is activated, the gas flow is the second group 3 of cylinders A, D to a pure air flow, the actual exhaust gas flow similar to the first group 2 after the first and before the second post-treatment as supplied in a secondary air injection. The extra oxygen can for a further oxidation of pollutants, in particular the oxidation of unburned hydrocarbons (HC) and carbon monoxide (CO), in Exhaust tract 7 serve.

The two arranged in front of the catalysts 12,14 lambda probes 11,13 serve Monitoring the air ratio to optimize the functioning of the Catalysts 12,14 and thus an optimal conversion of pollutants guarantee. Behind these catalysts 12,14 can additionally each OBD monitor lambda probe 17 are provided to provide advanced on-board diagnostics (OBD). It may alternatively only one OBD monitor lambda probe 17 are provided behind the second catalyst 14, used for on-board diagnostics (OBD) of both catalysts 12,14.

Figure 2 shows schematically a second embodiment of the multi-cylinder internal combustion engine 1. In contrast to that shown in Figure 1 Embodiment, the second embodiment has a different type Arrangement of the two arranged in the exhaust system 7 catalysts 12,14, in the will be discussed below. Otherwise, reference is made to FIG the same components, the same reference numerals have been used.

In the embodiment shown in Figure 2, the partial shutdown of Multi-cylinder internal combustion engine 1 also by switching off the second group. 3 of cylinders i. by switching off the two outer cylinders A, D.

The first lambda probe 11 and the first catalyst 12 are in the first exhaust pipe 8 arranged to the exhaust gases of the constantly operating cylinders B, C a Supply exhaust aftertreatment.

There are further a second lambda probe 13 and a second catalyst 14 provided, wherein the second lambda probe 13 and the second catalyst 14 at the embodiment of a multi-cylinder internal combustion engine shown in Figure 2 1 are arranged in the second exhaust pipe 9.

According to these embodiments, when partial deactivation is deactivated, the two exhaust gas streams of the two cylinder groups 2,3 aftertreated in the way that the exhaust gas flow of the first group 2 of cylinders B, C and the exhaust gas flow of second group 3 of cylinders A, D respectively in separate, in the first and second Exhaust pipe 8,9 arranged catalysts 12,14 an exhaust aftertreatment be subjected. Subsequently, the already aftertreated exhaust gas streams of the second group 3 of cylinders A, D and the first group 2 of cylinders B, C mixed and fed together to a total exhaust pipe 10.

What has said in Figure 1 in connection with the activated partial shutdown with regard to the post-oxidation of the pollutants also for this embodiment continued validity.

FIG. 3 shows schematically a third embodiment of the multi-cylinder internal combustion engine 1. In contrast to that shown in Figure 2 Embodiment, the third embodiment has an additional Catalyst 16 in the exhaust system 7, which will be discussed below. Furthermore Reference is made to FIGS. 1 and 2. The same components have become the same Reference numeral used.

In the embodiment shown in Figure 3, the Teilabschaltu ng takes place the Multi-cylinder internal combustion engine 1 also by switching off the second group. 3 of cylinders i. by switching off the two outer cylinders A, D.

The first lambda probe 11 and the first catalyst 12 are in the first exhaust pipe 8 arranged to the exhaust gases of the constantly operating cylinders B, C a Supply exhaust aftertreatment.

There are further a second lambda probe 13 and a second catalyst 14 provided, wherein the second lambda probe 13 in the second exhaust pipe 9 and the second catalyst 14 are arranged in the overall exhaust pipe.

The embodiment shown in Figure 3 of a multi-cylinder internal combustion engine 1 is characterized in that a third catalyst 16 is provided, wherein the third catalyst 16 in the second exhaust pipe 9 behind the second lambda probe 13 is arranged.

According to these embodiments, when partial deactivation is deactivated, the two exhaust gas streams of the two cylinder groups 2,3 aftertreated in the way that the exhaust gas flow of the first group 2 of cylinders B, C and the exhaust gas flow of second group 3 of cylinders A, D respectively in separate, in the first and second Exhaust pipe 8.9 arranged catalysts 12,16 an exhaust aftertreatment be subjected. Subsequently, the already aftertreated exhaust gas streams of the second group 3 of cylinders A, D and the first group 2 of cylinders B, C mixed and together another, arranged in the entire exhaust pipe 10 Catalyst 14 fed, in which they a further exhaust aftertreatment be subjected.

What has said in Figure 1 in connection with the activated partial shutdown with regard to the post-oxidation of the pollutants also for this third embodiment continued validity.

As in the embodiment shown in Figure 1 can also in the in the Figures 2 and 3 variants alternatively only one OBD monitor lambda probe 17 are provided behind the last catalysts, for on-board diagnosis (OBD) of all catalysts is used.

reference numeral

1

Multi-cylinder internal combustion engine, four-cylinder in-line engine

2

first group of cylinders

3

second group of cylinders

4

Intake tract, intake area

5

plenum

6

throttle

7

exhaust tract

8th

first exhaust pipe, first exhaust manifold

9

second exhaust pipe, second exhaust manifold

10

Total exhaust pipe

11

first lambda probe

12

first catalyst

13

second lambda probe

14

second catalyst

16

third catalyst

17

OBD monitor lambda probe

A

first cylinder

B

second cylinder

C

third cylinder

D

fourth cylinder

Claims (16)

Multi-cylinder internal combustion engine (1) with a lambda probe (11), a catalytic converter (12) and with a first group (2) of cylinders (B, C) and a second group (3) of cylinders (A, D), each comprising at least one cylinder (A, B, C, D) and of which the second group (3) of cylinders (A, D) can be switched off in the partial load range, the first group (2) of cylinders (B, C ) is provided with a separate first exhaust pipe (8) and the second group (3) of cylinders (A, D) with a separate second exhaust pipe (9),
characterized in that the lambda probe (11) and the catalytic converter (12) are arranged in the first exhaust pipe (8), a second lambda probe (13) and a second catalyst (14) are provided, wherein the second lambda probe (13) and the second catalyst (14) in the second exhaust pipe (9) or, if both exhaust pipes (8,9) in an overall exhaust pipe (10) open, the second lambda probe (13) in the second exhaust pipe (9) and the second catalyst (14) are arranged in this total exhaust pipe (10), and in the inlet region (4) of the cylinder (A, B, C, D) only a common, controllable throttle valve (6) is arranged, with the amount of combustion air, with which the cylinders (A, B, C, D) are acted upon , is metered, wherein the second group (3) of cylinders (A, D) is switched off in the partial load range, that the fuel supply to these cylinders (A, D) is prevented. Multi-cylinder internal combustion engine (1) according to Claim 1, in which the second lambda probe (13) and the second catalytic converter (14) are arranged in the second exhaust pipe (9) and the two exhaust pipes (8, 9) are arranged in an overall exhaust pipe (10). lead,
characterized in that
a third catalyst (16) is provided, wherein the third catalyst (16) in the total exhaust pipe (10) is arranged. Multi-cylinder internal combustion engine (1) according to claim 1, wherein the second lambda probe (13) in the second exhaust pipe (9) and the second catalyst (14) in the total exhaust pipe (10) are arranged,
characterized in that
a third catalyst (16) is provided, wherein the third catalyst (16) in the second exhaust pipe (9) behind the second lambda probe (13) is arranged. Multi-cylinder internal combustion engine (1) according to one of the preceding claims,
characterized in that
the throttle valve (6) is an electronically controlled throttle valve (6). Multi-cylinder internal combustion engine (1) according to one of the preceding claims,
characterized in that
behind the built-in catalysts (12,14,16) is provided in each case an OBD monitor lambda probe (17), so that an extended on-board diagnostic (OBD) is feasible. Multi-cylinder internal combustion engine (1) according to one of the preceding claims,
characterized in that
the multi-cylinder internal combustion engine (1) is a four-cylinder internal combustion engine (1). Multi-cylinder internal combustion engine (1) according to one of the preceding claims,
characterized in that
the multi-cylinder internal combustion engine (1) is an in-line engine (1). Multi-cylinder internal combustion engine (1) according to claim 7 with four cylinders (A, B, C, D),
characterized in that
the first group (2) of cylinders (B, C) comprises the two inner and second groups (3) of cylinders, the two outer cylinders (A, D). Multi-cylinder internal combustion engine (1) according to claim 7 with four cylinders,
characterized in that
the first group (2) of cylinders comprises the two outer cylinders (A, D) and the second group (3) of cylinders comprising the two inner cylinders (B, C). Method for partial shutdown of a multi-cylinder internal combustion engine (1) with a lambda probe (11), a catalytic converter (12) and with a first group (2) of cylinders (B, C) and a second group (3) of cylinders (A , D), both of which each comprise at least one cylinder (A, B, C, D) and of which the second group (3) of cylinders (A, D) in the partial load range can be switched off, wherein the first group (2) of cylinders (B, C) is equipped with a separate first exhaust pipe (8) and the second group (3) of cylinders (A, D) with a separate second exhaust pipe (9),
characterized in that in the inlet region (4) of the cylinder (A, B, C, D) only a common, controllable throttle valve (6) is arranged, with the amount of combustion air, with which the cylinders (A, B, C, D) are acted upon , is dosed, the second group (3) of cylinders (A, D) is switched off in the partial load range by inhibiting the supply of fuel to these cylinders (A, D), the lambda probe (11) and the catalytic converter (12) are arranged in the first exhaust pipe (8), a second lambda probe (13) and a second catalyst (14) are provided, wherein the second lambda probe (13) and the second catalyst (14) in the second exhaust pipe (9) or, if both exhaust pipes (8,9) in an overall exhaust pipe (10) open, the second lambda probe (13) in the second exhaust pipe (9) and the second catalyst (14) are arranged in this total exhaust pipe (10). A method for partial shutdown of a multi-cylinder internal combustion engine (1) according to claim 10, wherein the second lambda probe (13) and the second catalyst (14) in the second exhaust pipe (9) are arranged and the two exhaust pipes (8,9) in a Total exhaust pipe (10) open,
characterized in that
a third catalyst (16) is provided, wherein the third catalyst (16) in the total exhaust pipe (10) is arranged. Method for partial deactivation of a multi-cylinder internal combustion engine (1) according to Claim 10, in which the second lambda probe (13) is arranged in the second exhaust pipe (9) and the second catalyst (14) in the overall exhaust pipe (10),
characterized in that
a third catalyst (16) is provided, wherein the third catalyst (16) in the second exhaust pipe (9) behind the second lambda probe (13) is arranged. Method for partial deactivation of a multi-cylinder internal combustion engine (1) according to one of Claims 10 to 12,
characterized in that
as an adjustable throttle (6) an electronically controlled throttle valve (6) is used. Method for partial deactivation of a multi-cylinder internal combustion engine (1) according to one of Claims 10 to 13,
characterized in that
behind the built-in catalysts (12,14,16) each an OBD monitor lambda probe (17) is provided in order to perform an advanced on-board diagnostic (OBD) can. Method for partial deactivation of a four-cylinder in-line engine (1) according to one of Claims 10 to 14,
characterized in that
the first group (2) of cylinders (B, C) comprises the two inner and the second group (3) of cylinders the two outer cylinders (A, D), so that a partial shutdown of the internal combustion engine (1) by switching off the two outer Cylinder (A, D) takes place. Method for partial deactivation of a four-cylinder in-line engine (1) according to one of Claims 10 to 14,
characterized in that
the first group (2) of cylinders (A, D) the two outer and the second group (3) of cylinders, the two inner cylinders (B, C), so that a partial shutdown of the internal combustion engine (1) by switching off the two inner Cylinder (B, C) takes place.

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