Internal combustion engine for a motor vehicle, in particular for a motor car

Abstract

An internal combustion engine. Exhaust gas is flowable through an exhaust tract. Secondary air is flowable through a secondary air conduit and is introducible into the exhaust tract via the secondary air conduit. A mixture having secondary air introduced into the exhaust tract and fuel components is ignitable in the exhaust tract by an ignition device. Fresh air flowing through a suction tract is introducible into a combustion chamber via the suction tract. The secondary air conduit is fluidically connected to the suction tract at a diversion point where a portion of the fresh air in the suction tract is divertable from the suction tract by the secondary air conduit and is introducible into the exhaust tract as the secondary air. The fuel components that are contained in the exhaust gas, originate from the combustion chamber and reach the exhaust tract uncombusted from the combustion chamber.

Claims

1. An internal combustion engine for a motor vehicle, comprising: an exhaust tract fluidically coupled to a combustion chamber such that exhaust gas from the combustion chamber flows through the exhaust tract; a turbine in the exhaust tract and configured to be driven by the exhaust gas; a suction tract fluidically coupled to the combustion chamber so as to introduce air flowing in the suction tract into the combustion chamber; an intercooler in the suction tract; a throttle flap in the suction tract upstream of the intercooler and configured to adjust the amount of air introduced into the combustion chamber via the suction tract; a compressor in the suction tract upstream of the throttle flap and configured to compress the air flowing in the suction tract; a secondary air conduit fluidically coupling the suction tract to the exhaust tract at a diversion point downstream of the compressor so as to introduce a portion of the air flowing in the suction tract into the exhaust tract onto a turbine wheel of the turbine; and an ignition plug in the exhaust tract downstream of the turbine and configured to ignite a mixture of: (a) the air introduced into the exhaust tract, and (b) un-combusted fuel components in the exhaust gas.

2. The internal combustion engine according to claim 1, further comprising valve element, wherein the portion is adjustable by the valve element.

3. The internal combustion engine according to claim 2, wherein the valve element is a combination valve.

4. An internal combustion engine for a motor vehicle, comprising: an exhaust tract fluidically coupled to a combustion chamber such that exhaust gas from the combustion chamber flows through the exhaust tract; a turbine in the exhaust tract and configured to be driven by the exhaust gas; a suction tract fluidically coupled to the combustion chamber so as to introduce air flowing in the suction tract into the combustion chamber; an intercooler in the suction tract; a throttle flap in the suction tract upstream of the intercooler and configured to adjust the amount of air introduced into the combustion chamber via the suction tract; a compressor in the suction tract upstream of the throttle flap and configured to compress the air flowing in the suction tract; a secondary air conduit fluidically coupling the suction tract to the exhaust tract at a diversion point downstream of the compressor so as to introduce a portion of the air flowing in the suction tract into the exhaust tract into a bypass channel upstream of a wastegate valve, wherein the bypass channel bypasses the turbine in parallel flow with the exhaust tract; and an ignition plug in the exhaust tract downstream of the turbine and configured to ignite a mixture of: (a) the air introduced into the exhaust tract, and (b) un-combusted fuel components in the exhaust gas.

5. The internal combustion engine according to claim 4, further comprising valve element, wherein the portion is adjustable by the valve element.

6. The internal combustion engine according to claim 5, wherein the valve element is a combination valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic depiction of an internal combustion engine according to the invention according to a first embodiment; and

(2) FIG. 2 shows a schematic depiction of the internal combustion engine according to a second embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

(3) Identical or functionally identical elements are provided with the same reference signs in the figures.

(4) FIG. 1 shows, in a schematic depiction, an internal combustion engine 10 presently designed as a reciprocating piston engine for a motor vehicle, in particular for a motor car preferably designed as a passenger car. The motor vehicle in its completely produced state thus comprises the internal combustion engine 10 can be driven by internal combustion by means of the internal combustion engine 10. The internal combustion engine 10 comprises a cylinder housing 12, by which several cylinders 14 of the internal combustion engine 10 are formed or delimited. The respective cylinder 14 partially delimits a respective combustion chamber 16 of the internal combustion engine 10. During a fired operation of the internal combustion engine 10, combustion processes take place in the combustion chambers 16, from which exhaust gas of the internal combustion engine 10 results.

(5) The internal combustion engine 10 has an exhaust tract 18 that can be flowed through by the exhaust gas from the combustion chambers 16. The internal combustion engine 10 additionally comprises a secondary air conduit 20 that can be flowed through by secondary air, by means of which the secondary air flowing through the secondary air conduit 20 can be introduced into the exhaust tract 18, in particular at an introduction point E. The secondary air flowing through the secondary air conduit 20 bypasses the or all combustion chambers 16 of the internal combustion engine 10 and thus does not flow through the combustion chambers 16 or flows through no combustion chamber 16 of the internal combustion engine 10.

(6) The internal combustion engine 10 additionally has at least one or several ignition plugs 22, 24 arranged in the exhaust tract, wherein a mixture in the exhaust tract 18 can be ignited by means of the respective ignition plug 22 or 24. The mixture comprises the secondary air introduced into the exhaust tract 18 and uncombusted and thus still combustible fuel components, which have avoided at least one of the combustion chambers 16 uncombusted and reached the exhaust tract 18. The internal combustion engine 10 additionally comprises a suction tract 26 that can be flowed through by fresh air, by means of which the fresh air flowing through the suction tract 26 is fed to and into the combustion chambers 16.

(7) The internal combustion engine 10 comprises an exhaust turbocharger 28 that has a compressor 30 arranged in the suction tract 26 and a turbine 32 arranged in the exhaust tract 18. The turbine 32 can be driven by the exhaust gas, wherein the compressor 30 can be driven by the turbine 32, in particular via a shaft 34 of the exhaust turbocharger 28. By driving the compressor 30, the fresh air flowing through the suction tract 26 is compressed by means of the compressor 30.

(8) An intercooler 36 is arranged downstream of the compressor 30 and in particular upstream of the combustion chambers 16 in the flow direction of the fresh air flowing through the suction tract 26, by means of which the fresh air is cooled before it flows into the combustion chambers 16. A throttle flap 38 is additionally arranged in the suction tract 26. The throttle flap 38 is arranged upstream of the intercooler 36 and downstream of the compressor 30. By means of the throttle flap 38, a quantity of the fresh air to be fed to the combustion chambers 16 is adjusted. In FIG. 1 it can further be seen that, in particular by means of an exhaust manifold 40 arranged in the exhaust tract 18, two first ones of the combustion chambers 16 are combined into a first exhaust flow 42 and two second ones of the combustion chambers 16 are combined into a second exhaust flow 44. A respective first exhaust conduit 46a or 46b, for example formed by the exhaust manifold 40, is assigned to the respective first combustion chamber 16, wherein the exhaust conduits 46a, b are combined into the shared exhaust flow 42 or lead into the exhaust flow 42. A respective second exhaust conduit 48a or 48b is assigned to the respective second combustion chamber 16, wherein the exhaust conduits 48a and 48b lead into the shared exhaust flow 44 or are combined into the exhaust flow 44. The turbine 32 is thus preferably designed as a twin-pipe turbine.

(9) A bypass channel 50 is assigned to the turbine 32, which diverts away from the exhaust conduit 46b. In relation to the exhaust conduits 46a, b and 48a, b, the bypass channel 50 preferably diverts exclusively away from the exhaust conduit 46b. The bypass conduit 50 is fluidically connected to the exhaust tract 18 at a first connection point and at a second connection point. In particular, the bypass channel 50 is connected to the exhaust conduit 46b at the first connection point. At the first connection point, at least a part of the exhaust gas flowing through the exhaust conduit 46b can be diverted from the exhaust conduit 46b by means of the bypass channel 50 and introduced into the bypass channel 50. The exhaust gas introduced into the bypass channel 50 is guided to the second connection point by means of the bypass channel 50 and introduced into the exhaust tract 18 again at the second connection point. The first connection point is arranged upstream of the turbine 32, while the second connection point is arranged downstream of the turbine 32. The exhaust gas flowing through the bypass channel 50 thus bypasses the turbine 32. This means that the exhaust gas flowing through the bypass channel 50 does not drive the turbine 32. A valve element 52 is assigned to the bypass channel 50, by means of which a quantity of the exhaust gas flowing through the bypass channel 50 can be adjusted. A power of the turbine 32, and thus a boost pressure at which the fresh air is compressed by means of the compressor 30 can thus be adjusted, in particular controlled, by means of the bypass channel 50 and by means of the valve element 52.

(10) The exhaust tract 18 further has a connecting conduit 54, via which the bypass channel 50 and the exhaust flow 44 are or can be fluidically connected to each other. The valve element 52 is also described as a wastegate flap or wastegate valve, as the power of the turbines 32 and the boost pressure can be adjusted, in particular controlled by means of the valve element 52. The valve element 52 is additionally described as a flow connection lap or as a flow connection valve, as a quantity of the exhaust gas flowing through the connecting conduit 54 can for example be adjusted by means of the valve element 52. If the valve element 52 is closed, for example, such that the bypass channel 50 is closed, then the exhaust gas that flows into the bypass channel 50 at the first connection point for example flows into the exhaust flow 44 via the connecting conduit 54, such that for example the exhaust flow 44 is thus fluidically connected to the bypass channel 50 or to the exhaust conduit 46 b via the connecting conduit 54.

(11) It can be seen that the ignition plug 22 is arranged in the connecting conduit 54. The ignition plug 24 is arranged downstream of the turbine 32. It can be seen that the bypass channel 50 is in parallel flow connection with the turbine 32. The ignition plug 24 is in parallel flow connection with the turbine 32 and arranged downstream of the turbine 32 in the exhaust tract 18. The ignition plug 22 can be very squarely in flow connection with the turbine 32 and be arranged upstream of the turbine 32, or the ignition plug 22 is in parallel flow connection with the turbine 32.

(12) To obtain the secondary air in a particularly simple, and thus cost-, space- and weight-efficient manner, the secondary air conduit 20 for example fluidically connected to the exhaust tract 18 at the introduction point E is fluidically connected to the suction tract 26 at a diversion point A, which is arranged downstream of the compressor 30 and upstream of the throttle flap 38 in the flow direction of the fresh air flowing through the suction tract 26. By means of the secondary air conduit 20, at least a portion of the fresh air can be diverted from the suction tract 26 at the diversion point A and introduced into the secondary air conduit 20. The fresh air introduced into the secondary air conduit 20 flows through the secondary air conduit 20 and is fed to the introduction point E by means of the secondary air conduit 20 and introduced into the exhaust tract 18 as the secondary air at the introduction point E. A valve element 56 is assigned to the secondary air conduit 20, by means of which the portion and thus a quantity of the secondary or fresh air flowing through the secondary air conduit 20 can be adjusted. The valve element 56 is preferably a combination valve also simply described as a combi valve, as on the one hand the valve element 56 is used to adjust the portion, i.e., to adjust the quantity of the secondary air flowing through the secondary air conduit 20. On the other hand, the valve element 56 is for example designed as a thrust air recirculation valve, via which for example, when the throttle flap 38, having first been opened, is closed quickly, at least a portion of the fresh air first arranged between the compressor 30 and the throttle flap 38 can be diverted out of the suction tract 26. If the throttle flap 38 is closed abruptly, an excessive deceleration of the compressor 30 or its compressor wheel can thus be avoided. From FIG. 1, it can be seen that a secondary air system is combined with a thrust air recirculation system to provide the secondary air, such that overall, in comparison with conventional solutions, actuators and pumps are not required. The secondary air system and the thrust air recirculation system can thus be obtained in a weight-, space- and cost-efficient manner.

(13) For example, the introduction point E is arranged in the exhaust manifold 40, such that the secondary air is injected or introduced into the exhaust manifold. The introduction or injection of the secondary air into the exhaust tract 18 is also described as air injection or secondary air injection. The ignition plug 24 is preferably arranged in the region of an outlet of the turbine 32. If, for example, at least one of the combustion chambers 16 provides a rich combustion chamber mixture, which comprises uncombusted, and thus combustible and preferably liquid fuel, including the previously specified fuel components, then the rich combustion chamber mixture is mixed with the secondary air, whereby the previously specified mixture is formed. By means of the respective ignition plug 22 or 24, the mixture can be ignited early and in a targeted manner, such that a particularly low-emission operation can be represented.

(14) FIG. 2 shows a second embodiment of the internal combustion engine 10. In the second embodiment, the introduction point E is for example spaced apart from the exhaust manifold, and in particular arranged downstream of the turbine 32, in particular at an outlet of a turbine rotor of the turbine 32 of which the turbine rotor for example comprises a turbine wheel of the turbine. It is further conceivable that the introduction point E is arranged in a course of the turbine rotor. This can in particular be understood to mean that, for example, the introduction point E is arranged in flow connection at the same height as the turbine wheel in the flow direction of the exhaust gas flowing through the exhaust tract 18.

(15) An advantage of the internal combustion engine 10 is that the secondary air can be injected into a region having only low counter-pressure. A sufficient pressure drop thus always exists between the diversion point A arranged downstream of the compressor 30 and the introduction point E. Additionally, a flow turbulence after the turbine 32 can be used to combust the secondary air with the fuel components or with the rich combustion chamber mixture particularly advantageously. The ignition plugs 22 and 24 are additionally used to ignite the mixture, also described as firing, whereby the mixture can be effectively, cost-efficiently and space-efficiently ignited early.

(16) An exhaust gas post-treatment device for post-treating the exhaust gas is preferably arranged downstream of the respective ignition plug 22 or 24 and also downstream of the introduction point E in the flow direction of the exhaust gas. The exhaust gas post-treatment device comprises, for example, at least one catalytic converter, which can be designed as a three-way catalytic converter or as an SCR catalytic converter. By igniting and combusting the mixture, the exhaust gas post-treatment device can be particularly quickly and efficiently heated, such that a particularly efficient heating, in particular catalyst heating, can be obtained, as a turbine housing of the turbine 32 does not need to be heated. In particular, components already present, in particular and above all in the form of the thrust air recirculation valve can be used to represent a particularly low-emission operation of the internal combustion engine 10.

LIST OF REFERENCE CHARACTERS

(17) 10 internal combustion engine 12 cylinder housing 14 cylinder 16 combustion chamber 18 exhaust tract 20 secondary air conduit 22 ignition plug 24 ignition plug 26 suction tract 28 exhaust turbocharger 30 compressor 32 turbine 34 shaft 36 intercooler 38 throttle flap 40 exhaust manifold 42 exhaust flow 44 exhaust flow 46a, 46b exhaust conduit 48a, 48b exhaust conduit 50 bypass channel 52 valve element 54 connecting conduit 56 valve element A diversion point E introduction point