DE102016219320A1 - internal combustion engine - Google Patents

Abstract

The invention relates to an internal combustion engine (1) comprising an intake pipe (6) with a throttle valve (10) for supplying fresh air to cylinders (2, 3, 4, 5) of the internal combustion engine (1), an exhaust pipe (7) for discharging exhaust gas from the cylinders (2, 3, 4, 5), an exhaust gas recirculation line (8) for recirculating exhaust gas from the exhaust pipe (7) into the intake pipe (6), a bypass pipe (9) for sucking fresh air while bypassing the exhaust gas recirculation Exhaust gas recirculation line (8), wherein the bypass line (9) downstream of the throttle valve (10) opens into the intake line (6), and an additional valve (11) between the throttle valve (10) and the bypass line (9) in the intake line (6 ) is arranged.

Description

The present invention relates to an internal combustion engine. Moreover, the invention relates to a vehicle comprising such an internal combustion engine. The internal combustion engine is in particular a gasoline engine with exhaust gas recirculation.

From the prior art internal combustion engines are known which have an exhaust gas recirculation. In a gasoline engine such exhaust gas recirculation is usually used to achieve consumption benefits. These are usually justified by improved material properties, by Entdrosselung or reduction of the charge exchange work at part load, by lowering the tendency to knock by reducing the gas temperatures at full load, and by recycling unburned fuel residues.

Since combustion in gasoline engines, however, tolerates heavily fluctuating rates of exhaust gas recirculation via the load, all exhaust gas recirculation rates during operation of the internal combustion engine, in particular when it is used in vehicles, are difficult to achieve. Especially in so-called tip-outs, that is load shedding, the operating point of the internal combustion engine within the engine map is changed rapidly within a very short time. Thus, there may be instances where the operating point shifts within a short time from high exhaust gas recirculation optimal rate regions to low optimal exhaust gas recirculation rate regions. Thus, the high rate of exhaust gas recirculation must be lowered to avoid irregularities or even dropouts during combustion. However, it is often not possible to quickly reduce rates of exhaust gas recirculation because there are gas passages between a valve of the exhaust gas recirculation and intake valve of the individual cylinders, which are filled with a gas mixture at a high rate of exhaust gas recirculation. For these reasons, internal combustion engines are usually designed so that not the optimal exhaust gas recirculation rate is used, but one that does not lead to irregularities or dropouts during combustion even at low loads. Thus, the possibilities of exhaust gas recirculation can not be fully exploited.

It is therefore an object of the invention to provide an internal combustion engine which has an optimal exhaust gas recirculation with simple and cost-effective production and assembly.

The object is achieved by the features of the independent claim. The dependent claims have preferred developments of the invention to the content.

Thus, the object is achieved by an internal combustion engine comprising an intake pipe, an exhaust pipe, an exhaust gas recirculation pipe and a bypass pipe. It is provided that the intake is provided with a throttle valve. Fresh air to cylinders, in particular to all cylinders, of the internal combustion engine can be conducted via the intake line. This supply of fresh air is adjustable via the throttle. Thus, a power of the internal combustion engine can be controlled in particular via the throttle valve. The exhaust pipe serves to discharge exhaust gas from the cylinders, in particular to all cylinders of the internal combustion engine. The cylinders are configured to carry out the combustion and convert the resulting energy into rotational energy. Exhaust gas from the exhaust pipe can be returned to the intake pipe via the exhaust gas recirculation line. The bypass line 9 serves to suck in fresh air, bypassing the exhaust gas recirculation through the exhaust gas recirculation line. Thus, through the bypass line at any time fresh air, which is free of recirculated exhaust gases, the cylinders of the engine fed. For this purpose, it is provided that the bypass line opens downstream of the throttle valve into the intake passage. Thus, a position of the throttle has no effect on the bypass line. In addition, it is provided that an additional valve between the throttle valve and the bypass line is arranged in the intake passage. If the additional valve is closed, an underpressure in the bypass line can be generated by an intake stroke of one of the cylinders. In this way, fresh air is additionally sucked, so as to influence a mixing ratio of a mixture of recirculated exhaust gas and fresh air, which is located in the suction line, before feeding to the cylinders. Fresh air can be supplied to all cylinders through the bypass line in a particularly advantageous manner. The bypass line advantageously makes it possible to reduce high exhaust gas recirculation rates rapidly, so that there is no risk of irregular combustion taking place within the cylinders. It is also particularly advantageous to avoid misfires during combustion within the cylinders. This always allows optimal return rates of the exhaust gas, so that the potential and the advantages of the exhaust gas recirculation can be optimally exploited.

Preferably, the intake manifold included a collection device. From the collecting device branches off each have their own cylinder intake, so that each cylinder has its own cylinder intake. The cylinder intake line is used exclusively for transporting fresh air to a single cylinder. It is provided that the bypass line opens into the collection device or in each cylinder intake. Thus, it is ensured that a flow path of the Mouth of the bypass line is minimized to the cylinders. This allows a rapid reduction of an exhaust gas recirculation rate, since a reservoir effect of the intake pipe is minimized. This means that an amount of gas between the bypass line and the cylinders is minimized, so that due to the minimized gas path no disturbances in the combustion can occur because of not fast enough degraded high exhaust gas recirculation rates.

Particularly advantageously, the additional valve is faster than the throttle actuated. This ensures that throttling the suction line is minimized. Thus, it is particularly avoided that a fuel consumption increases due to increased load change work. In addition, the minimized throttling of the intake line prevents the compressor of an exhaust-gas turbocharger from entering a pumping area. This would lead to damage to the exhaust gas turbocharger.

The additional valve is preferably a rotating charge air valve. Under a rotating charge air valve is to be understood in particular that an actuator of the charge air valve performs a continuous rotation. In this way, the suction line is closed only briefly, so that opening the intake immediately follows the closing. It follows that also the generation of a negative pressure within the suction line is limited in time. In this way, the above-mentioned advantages with regard to the minimized throttling of the intake line can be achieved.

The additional valve preferably has a rotatable flap disposed within a valve seat. It is provided that the flap completely closes the valve seat in a predefined position and releases it in all other positions. The rotatable flap preferably performs a continuous rotation. By means of a rotational speed, it is thus possible to set a frequency of the complete closing of the suction line per unit of time. Since a complete closing of the intake line leads to a negative pressure in the bypass line, fresh air can be safely and reliably sucked in this way. In particular, high rates of exhaust gas recirculation can thus be minimized if an operating point of the internal combustion engine shifts within the engine map. Also, a return flow of exhaust gas-air mixture is prevented in the bypass line.

Particularly advantageously, the additional valve has a drive motor. The drive motor is used for continuous rotation of the flap. The drive motor is in particular a brushless electric motor, in particular a brushless DC motor. This has a high dynamic and thus allows a quick adjustment of the additional valve. Thus, it is possible to react quickly to a changed operating point of the internal combustion engine.

In the intake line, a compressor of a turbocharger is preferably arranged. The bypass line branches off the intake line upstream of the compressor. Thus, both a low-pressure exhaust gas recirculation and a high-pressure exhaust gas recirculation is possible. In any case, it is ensured that the bypass line sucks in fresh air completely without exhaust gases.

Particularly advantageous is also provided that the exhaust gas recirculation line branches off downstream of a turbine of the turbocharger from the exhaust pipe and opens upstream of the compressor and downstream of the bypass line into the intake. Thus, a low-pressure exhaust gas recirculation is realized. This means that a mixture of compressed fresh air and exhaust gas is always present via the intake line, wherein the proportion of the exhaust gas is adjustable via a preferably present in the exhaust gas recirculation line valve. If the proportion of the exhaust gas to be changed, this is only possible by changing the valve position. However, a fresh air-exhaust mixture must first pass through the entire intake to get to the cylinders of the engine. Thus, there is a delay in the adjustability of the exhaust gas recirculation rate. However, in order to avoid disturbances of the combustion of the cylinder in abrupt change of the operating point of the internal combustion engine within the engine map, the exhaust gas recirculation rate is adjustable via the intake of additional air via the bypass line. This happens almost delay.

The bypass line preferably has a bypass valve. The bypass valve is used to set a flow of fresh air through the bypass line. In particular, the bypass valve is regulated in dependence on a position of the throttle valve. It is already ensured by the additional valve that the bypass line is always filled with fresh air, as a return flow of exhaust gas fresh air mixture is avoided in the bypass line. Thus, no complex control strategy is needed to couple the by-pass valve of the type to the throttle that is such a return flow through the interplay of the throttle and bypass valve positions.

Finally, the invention relates to a vehicle having an internal combustion engine as described above. The internal combustion engine is in particular a gasoline engine. The inventive use of a bypass line as described above ensures that always optimal exhaust gas recirculation rates can be used because of the Bypass line a high exhaust gas recirculation rate can be rapidly reduced at any time, should an operating point of the internal combustion engine require this.

Further details, features and advantages of the invention will become apparent from the following description and the figures. Show it:

1 a schematic illustration of an internal combustion engine according to an embodiment of the invention, and

2 a schematic illustration of a vehicle according to an embodiment of the invention.

1 schematically shows an internal combustion engine 1 according to an embodiment of the invention. The internal combustion engine 1 comprises a plurality of cylinders, in particular a first cylinder 2 , a second cylinder 3 , a third cylinder 4 and a fourth cylinder 5 , The cylinders 2 . 3 . 4 . 5 is via a suction line 6 Fresh air can be supplied. For this purpose, the suction line 6 first an intake silencer 26 on. Downstream of the intake silencer 26 is in the intake pipe 6 a compressor 20 an exhaust gas turbocharger 21 available. About the compressor 20 is sucked fresh air compressible. The compressed fresh air passes one inside the intake pipe 6 arranged intercooler 24 before this one throttle 10 happens. About the throttle 10 is thus a performance of the internal combustion engine 1 adjustable.

The suction line 6 flows into a collecting device 16 , From the collection device 16 performs a first cylinder intake line 12 to the first cylinder 2 , a second cylinder suction line 13 to the second cylinder 3 , a third cylinder intake line 14 to the third cylinder 4 and a fourth cylinder intake passage 15 to the fourth cylinder 5 , That's how each cylinder is 2 . 3 . 4 . 5 supplied with fresh air.

On an exhaust side of the cylinder 2 . 3 . 4 . 5 there is an exhaust pipe 7 for discharging the exhaust gases of the cylinders 2 . 3 . 4 . 5 , The exhaust pipe 7 includes an exhaust manifold 29 , which absorbs exhaust gases from all cylinders 2 . 3 . 4 . 5 serves to line up these exhaust gases together 21 the exhaust gas turbocharger 22 supply. From the turbine 21 The exhaust gases enter a catalyst 25 to be subsequently delivered to an environment. About the turbine 21 is the compressor described above 20 drivable.

Downstream of the turbine 21 branches off the exhaust pipe 7 an exhaust gas recirculation line 8th from. Exhaust gas recirculation line 8th opens in the intake pipe 6 upstream of the compressor 20 and, in particular, downstream of the intake silencer 26 , The exhaust gas recirculation line 8th includes an exhaust gas recirculation cooler 27 and an exhaust gas recirculation valve 28 , About the exhaust gas recirculation valve 28 is an exhaust gas recirculation rate adjustable. The exhaust gas recirculation is thus a low-pressure exhaust gas recirculation.

The exhaust gas recirculation points with respect to different operating points of the internal combustion engine 1 within a motor map different optimal rates. Since the operating point of the internal combustion engine 1 However, within the engine map can change rapidly, an equally rapid adjustment of the exhaust gas recirculation rate is necessary. In particular, a rapid lowering of the exhaust gas recirculation rate is to be carried out if this is necessary due to a change in the operating point of the internal combustion engine. Otherwise, there is a risk of incidents of combustion within the cylinder 2 . 3 . 4 . 5 occur. Due to the long gas line between the exhaust gas recirculation valve 28 and the cylinders 2 . 3 . 4 . 5 , such a rapid lowering may have an exhaust gas recirculation rate through the exhaust gas recirculation valve 28 alone can not be accomplished. Therefore, the internal combustion engine points 1 in addition a bypass line 9 on.

The bypass line 9 is used to suck in fresh air, without this fresh air is contaminated by the exhaust gas recirculation with exhaust gases. The bypass line 9 flows into the collecting device 16 , In the in 1 the embodiment shown branches the bypass line 9 from the intake pipe 6 upstream of the confluence of the exhaust gas recirculation line 8th from. In this way it is ensured that no recirculated exhaust gases into the bypass line 9 can reach.

By opening the bypass line 9 in the collection device 16 can be in close proximity to the cylinders 2 . 3 . 4 . 5 in the intake line 6 existing fresh air mixture mixture more fresh air to be mixed. In this way, the proportion of the exhaust gas in the total mixture is reducible. Since the gas line between the junction of the bypass line 9 and the cylinders 2 . 3 . 4 . 5 is minimized, can thus quickly change to the operating point of the internal combustion engine 1 be reacted. An air flow through the bypass line 9 is through a bypass valve 23 adjustable.

However, to avoid the exhaust-fresh air mixture from the intake pipe 6 in the bypass line 9 thereby passes that by opening the bypass valve 23 said exhaust gas fresh air mixture from the collector 16 due to overpressure in the collection device 16 in the bypass line 9 flows, is an additional valve 11 available. The additional valve 11 serves to close the suction line 6 so that within the collection device 16 and thus also in the bypass line 9 a negative pressure is created. Thus, by the bypass line 9 Fresh air sucked. A stream of exhaust fresh air mixture from the collector 16 in the bypass line 9 is thus prevented.

Will the suction line 6 However, throttled, there is a risk that the compressor 20 a pumping state device. Such a condition would damage the exhaust gas turbocharger 11 entail. Therefore, it is provided that the additional valve 11 the suction line 6 only short-term closes. Therefore, the additional valve 11 preferably designed as a fast-switching charge air valve. The additional valve 11 preferably comprises a valve seat 18 and a rotatable flap 17 , The rotatable flap 17 is from a drive motor 19 driven so that the rotatable flap 17 performs a continuous rotation. In the drive motor 19 it is in particular a brushless DC motor. Through the rotatable flap 17 is the valve seat 18 in a position of the rotatable flap 17 lockable, while in all other positions of the rotatable flap of the valve seat 18 is released. Thus, immediately on a closing of the valve seat 18 through the rotatable flap 17 a release of the valve seat 18 , This means that the intake pipe 6 is closed only for a time, whereby only a short-term negative pressure within the bypass line 9 can be generated. In this way is a strong throttling of the intake pipe 6 prevents, so that is avoided that the compressor 20 in a pumping state device.

Through the additional valve 11 Thus, it is also ensured that fresh air within the bypass line at any time 9 is available. This avoids, in particular, the provision of a complex control strategy between the throttle valve 10 and bypass valve 23 , which without additional valve 11 would be necessary to reverse flow of exhaust fresh air mixture into the bypass line 9 to avoid.

In 1 is shown that the bypass line 9 in the collection device 16 empties. In another alternative, the bypass line 9 also in the first cylinder intake line 12 , into the second cylinder intake line 13 , into the third cylinder intake line 14 and into the fourth cylinder intake passage 15 lead. In this case, a gas line between the mouth of the bypass line 9 and the countries 2 . 3 . 4 . 5 further reduced, which allows an even faster change in the exhaust gas recirculation rates.

2 schematically shows a vehicle 30 comprising an internal combustion engine 1 , The internal combustion engine 1 corresponds in particular to the previously described and in 1 shown internal combustion engine 1 , The internal combustion engine 1 is in particular a gasoline engine. The vehicle 30 thus allows optimal exhaust gas recirculation for the internal combustion engine 1 to use.

Especially in internal combustion engines 1 in vehicles 30 are used with a rapid change of an operating point of the internal combustion engine 1 to count. Therefore, adjusting the exhaust gas recirculation rate is essential to suspend the engine 1 due to combustion disturbances within the cylinder 2 . 3 . 4 . 5 to avoid. By the previously described internal combustion engine 1 is such a rapid adjustment possible, whereby overall higher exhaust gas recirculation rates as prior art for operating the internal combustion engine 1 can be used. In this way, a potential of the exhaust gas recirculation can be optimally exploited, whereby advantages with regard to the operation of the internal combustion engine 1 be achieved.

LIST OF REFERENCE NUMBERS

1

internal combustion engine

2

first cylinder

3

second cylinder

4

 third cylinder

5

 fourth cylinder

6

 suction

7

 exhaust pipe

8th

 Exhaust gas recirculation line

9

 bypass line

10

throttle

11

additional valve

12

first cylinder intake line

13

second cylinder intake line

14

third cylinder suction line

15

fourth cylinder intake line

16

collection device

17

rotatable flap

18

valve seat

19

drive motor

20

compressor

21

turbine

22

turbocharger

23

bypass valve

24

Charge air yes

25

catalyst

26

Ansauggeräuschdämpfer

27

Exhaust gas recirculation cooler

28

Exhaust gas recirculation valve

29

exhaust manifold

30

vehicle

Claims (10)

Internal combustion engine ( 1 ) full • a suction line ( 6 ) with a throttle valve ( 10 ) for supplying fresh air to cylinders ( 2 . 3 . 4 . 5 ) of the internal combustion engine ( 1 ), • an exhaust pipe ( 7 ) for removing exhaust gas from the cylinders ( 2 . 3 . 4 . 5 ), • an exhaust gas recirculation line ( 8th ) for recirculating exhaust gas from the exhaust pipe ( 7 ) into the suction line ( 6 ), • a bypass line ( 9 ) for the intake of fresh air, bypassing the exhaust gas recirculation through the exhaust gas recirculation line ( 8th ), whereby the bypass line ( 9 ) downstream of the throttle valve ( 10 ) into the suction line ( 6 ), and • an additional valve ( 11 ) between the throttle valve ( 10 ) and the bypass line ( 9 ) in the intake line ( 6 ) is arranged. Internal combustion engine ( 1 ) according to claim 1, characterized in that the suction line ( 6 ) a collecting device ( 16 ), wherein from the collecting device ( 16 ) a single cylinder intake line ( 12 . 13 . 14 . 15 ) to each cylinder ( 2 . 3 . 4 . 5 ), and wherein the bypass line ( 9 ) into the collecting device ( 16 ) or in each individual cylinder intake line ( 12 . 13 . 14 . 15 ) opens. Internal combustion engine ( 1 ) according to one of the preceding claims, characterized in that the additional valve ( 11 ) faster than the throttle ( 10 ) is operable. Internal combustion engine ( 1 ) according to one of the preceding claims, characterized in that the additional valve ( 11 ) is a rotating charge air valve. Internal combustion engine ( 1 ) according to one of the preceding claims, characterized in that the additional valve ( 11 ) one within a valve seat ( 18 ) arranged rotatable flap ( 17 ), wherein the flap ( 17 ) in a predefined position the valve seat ( 18 ) completely closes and releases in all other positions. Internal combustion engine ( 1 ) according to claim 5, characterized in that the additional valve ( 11 ) a drive motor ( 19 ) for continuously rotating the flap ( 17 ) having. Internal combustion engine ( 1 ) according to one of the preceding claims, characterized in that in the suction line ( 6 ) a compressor ( 20 ) of a turbocharger ( 22 ), wherein the bypass line ( 9 ) upstream of the compressor ( 20 ) from the intake line ( 6 ) branches off Internal combustion engine ( 1 ) according to claim 7, characterized in that the exhaust gas recirculation line downstream of a turbine ( 21 ) of the turbocharger ( 22 ) from the exhaust pipe ( 7 ) branches off and upstream of the compressor ( 20 ) and downstream of the bypass line ( 9 ) into the suction line ( 6 ) opens. Internal combustion engine ( 1 ) according to one of the preceding claims, characterized in that in the bypass line ( 9 ) a bypass valve ( 23 ) for adjusting a flow of fresh air through the bypass line ( 9 ) is arranged. Vehicle ( 30 ) comprising an internal combustion engine ( 1 ) according to any one of the preceding claims.

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