DE102011083904A1 - Combustion arrangement with an internal combustion engine and an exhaust gas channel and method for exhaust aftertreatment of an internal combustion engine - Google Patents

Abstract

The invention relates to a combustion arrangement with an internal combustion engine 10 and connected to the internal combustion engine 10 exhaust system 50, and a method for exhaust aftertreatment of an internal combustion engine 10, the exhaust system 50 having an exhaust passage 51 for discharging an exhaust gas of the internal combustion engine 10 and a device for post-treatment of the exhaust gas , The internal combustion engine 10 has a combustion chamber 15, which is delimited by a piston 20. The piston 20 defines on a side facing away from the combustion chamber 15 a crankcase 30. The crankcase 30 is configured such that due to a movement of the piston 20, a gas, in particular air, is compressed in the crankcase 30. The crankcase 30 is connected to the exhaust system 50 in such a way that the gas compressed in the crankcase 30 is supplied to the exhaust system 50.

Description

State of the art

The invention relates to a combustion arrangement with an internal combustion engine and an exhaust system and a method for exhaust aftertreatment of an internal combustion engine according to the preamble of the independent claims.

In the case of internal combustion engines, the emission standards for harmful exhaust gas components such as soot particles, unburned hydrocarbon compounds or nitrogen oxides must be further and further reduced due to increasingly stringent emission standards. To remove nitrogen oxides, especially in diesel engines, so-called SCR catalysts for the selective catalytic reduction of nitrogen oxides are used. From the DE 199 61 947 An exhaust aftertreatment system for an internal combustion engine is already known, in which a liquid reducing agent is conveyed by a feed pump into a mixing chamber. In the mixing chamber, an aerosol is generated by means of compressed air from the liquid reducing agent and metered this aerosol via an aerosol line in the exhaust passage of the internal combustion engine. Furthermore, from the DE 10 2005 034 704 known to introduce a regeneration agent in the exhaust passage for the regeneration of a particulate filter.

From the DE 69522311 It is known to use a crankcase of an internal combustion engine for compressing air and to supply this compressed air to increase performance of an intake passage of the internal combustion engine.

epiphany

The combustion arrangement according to the invention and the inventive method for exhaust aftertreatment of an internal combustion engine with the features of the independent claims have the advantage that the movement of the piston is used to compress a gas, in particular air in the crankcase and supply this compressed gas to the exhaust system, by the compression of the gas in the crankcase by the piston of the internal combustion engine to an external supply device for the gas, such as a pressure accumulator or an additional compressed air generator, can be dispensed with. Thus, a supply of the compressed gas to the exhaust system without additional components and thus can be realized very inexpensively.

The measures listed in the dependent claims advantageous refinements and improvements of the specified combustion arrangement and the specified method are possible.

An advantageous development is that the piston is movably arranged in a cylinder, the piston, the combustion chamber and the crankcase, apart from leakage losses between the piston and the cylinder, fluid-tight from each other. By a fluid-tight separation of combustion chamber and crankcase of the combustion chamber side acting pressure on the piston can be used to drive the piston in its movement towards the crankcase and to achieve effective compression of the gas in the crankcase, so that there is a pressure increase in the crankcase comes. By sealing the crankcase relative to the combustion chamber, a gas exchange between the crankcase and the combustion chamber and thus a pressure reduction in the crankcase is largely prevented here.

A further advantageous development of the combustion arrangement is that the crankcase is connected via a bypass line to the exhaust passage of the exhaust system, whereby the compressed gas from the crankcase for exhaust aftertreatment in the exhaust duct or for conditioning the exhaust duct can be used.

A further advantageous development of the combustion arrangement is that the exhaust system conveying means, which promote a fluid, in particular a fluid for exhaust aftertreatment, for example, aqueous urea solution or a fuel of the internal combustion engine in the exhaust duct. Alternatively, it is also advantageously provided that the exhaust system comprises dosing means which meter the fluid into the exhaust duct. Particularly advantageous is a combination of funding and dosing, which promote the fluid from a reservoir and metered into the exhaust passage of the internal combustion engine. In particular, however, the gas can be used from the crankcase to atomize the fluid supplied by the conveyor or to promote combustion of the fluid in the exhaust passage.

It is particularly advantageous if the funding is driven by the compressed gas from the crankcase. The drive of the conveyor by the pressurized fluid in the crankcase has the advantage to dispense with an additional, mechanical or electrical, drive for the funding. This waiver not only increases the efficiency of the reciprocating engine, but also reduces the costs in parallel. Alternatively, it is advantageously provided that pressure fluctuations are generated by the piston of the internal combustion engine in the crankcase, whereby pulses are produced by the pressure fluctuations either directly, to convey the fluid, or indirectly, to drive a fluid delivery means. Also in this embodiment can be dispensed with further electrical or mechanical energy for the funding, which reduces the assembly effort, since no additional lines, especially not in hard to reach places, must be installed or connected.

A further advantageous development consists in that the conveying means comprise a diaphragm pump, which is driven by the pressure fluctuations in the crankcase. If the internal combustion engine is a reciprocating engine, the gas in the crankcase of the reciprocating engine is cyclically compressed and expanded by the oscillating movement of a piston of the reciprocating engine, whereby pressure fluctuations in the crankcase arise. These pressure fluctuations can be used in a simple manner to drive a diaphragm pump. In particular, it is advantageous if a membrane pump driven by the gas in the crankcase conveys a fluid other than the gas into the exhaust gas duct. By using the diaphragm pump for conveying a liquid fluid such as aqueous urea solution or fuel can be dispensed with an additional, different from the diaphragm pump, delivery unit for the fluid. As a result, the number of components can be reduced, whereby the cost of material and assembly is reduced.

An advantageous development is that the dosing means are arranged on the bypass line. As a result of the arrangement of the dosing means on the bypass line, the fluid can be metered into the bypass line. By an appropriate geometric design of the bypass line and a targeted introduction of the compressed gas from the crankcase in the bypass line, the bypass line can be easily conditioned, whereby a more uniform distribution of the fluid can be achieved as in a direct metering into the exhaust passage. In addition, the dosing means are less thermally stressed in an arrangement on the bypass line as in an arrangement on the exhaust duct, where the dosing may be damaged by the hot exhaust gas in the exhaust duct.

It is particularly advantageous if the dosing, at least partially, are sheathed by the bypass line, wherein the dosing means are cooled by the compressed in the crankcase and flowing through the bypass gas. By cooling with the gas from the crankcase can be realized in a simple and cost-effective manner cooling the dosing or the fluid, whereby thermal damage to the dosing and decomposition, aging or crystallization of the fluid can be prevented or at least slowed down.

As a further advantageous development, it is provided that the dosing means comprise a metering valve, in particular a pressure-controlled metering valve, or a carburettor. Via a metering valve, the amount of the metered fluid can be controlled, so that according to the exhaust gas amount, the exhaust gas composition and / or the exhaust gas temperature can be metered in each case a need-based amount of fluid through the metering valve. In particular, it is advantageous if the metering valve is designed as a pressure-controlled metering valve which opens depending on the pressure in the crankcase and / or in a supply line for the fluid. By such a pressure-controlled metering valve can be dispensed with a complex electrical or pneumatic control of the metering valve, whereby the thermal load capacity of the metering valve increases. Alternatively, there is an advantageous development in that the dosing comprise a carburetor for the fluid. A carburetor is another favorable alternative to the introduction of a fluid to support the exhaust aftertreatment in the exhaust passage, which is particularly suitable for a easily volatilizing fluid, with a boiling point well below the usual in the operation of the internal combustion engine temperatures in the exhaust passage to this fluid in to transfer the gaseous state and metered into the exhaust passage of the internal combustion engine.

drawings

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

1 shows a first embodiment of a combustion device according to the invention.

2 shows a further embodiment of a combustion arrangement according to the invention, with dosing means on a bypass line which connects the crankcase with the exhaust duct.

3 shows a further embodiment of a combustion device according to the invention, with a diaphragm pump which is driven by pressure oscillations in the crankcase.

4 shows a further embodiment of a combustion device according to the invention, in which dosing are cooled by the gas from the crankcase.

5 shows a combustion arrangement according to the invention with a two-cylinder Boxer engine.

Brief description of the drawings

The invention and advantageous embodiments according to the features of the other claims are explained in more detail below with reference to the embodiments illustrated in the drawings. In the figures, the same components or components with the same function with the same reference numerals.

In the 1 is a combustion arrangement according to the invention with an internal combustion engine 10 shown. The internal combustion engine 10 includes a crankcase 30 in which a crankshaft 40 is arranged. The crankshaft 40 is over a connecting rod 34 with a piston 20 the internal combustion engine 10 connected. The piston 20 the internal combustion engine 10 is in a cylinder 18 slidably arranged. The internal combustion engine 10 has a combustion chamber 15 on, which has an inlet 12 with a suction channel 14 and an outlet 13 with an exhaust duct 51 an exhaust system 50 connected is. Here are the inlet 12 through a valve 17 and the outlet 13 through a valve 19 closable. The combustion chamber 15 the internal combustion engine 10 is in the cylinder 18 through the piston 20 limited, with a seal of the combustion chamber 15 between the piston 20 and the cylinder 18 via piston rings 35 on the piston 20 he follows. To the cylinder 18 closes the crankcase 30 at. The piston 20 is over a connecting rod 34 with the crankshaft 40 connected. The crankcase 30 the internal combustion engine 10 is over a line 16 with the intake channel 14 connected to the crankcase 30 an inlet valve 38 is arranged, via which a connection between the crankcase 30 and the line 16 is closable. Further, the crankcase 30 via a bypass line 33 with the exhaust duct 51 the internal combustion engine 10 connected to the crankcase 30 an outlet valve 39 is arranged, over which the connection of crankcase 30 and bypass line 33 is closable.

In the exhaust system 50 is for cleaning the exhaust gas of the internal combustion engine 10 at least one device 52 . 54 . 56 arranged for exhaust aftertreatment. In the embodiment according to 1 are shown in the exhaust passage three devices for exhaust aftertreatment, wherein for cleaning the exhaust gas of the internal combustion engine 10 in the exhaust gas flow direction, an oxidation catalyst 52 , a particle filter 54 and a catalyst 56 for the selective reduction of nitrogen oxides are connected in series. The bypass line 33 flows between the outlet 13 the internal combustion engine 10 and the oxidation catalyst 52 in the exhaust duct 50 ,

The internal combustion engine 10 sucks air in a known manner through the intake passage 14 which is in the combustion chamber 15 through the piston 20 is compressed. A fuel gets into the combustion chamber 15 injected, which deals with the air in the combustion chamber 15 mixed to form a fuel-air mixture. A compression of the fuel-air mixture by the piston 20 leads to an increase of pressure and temperature in the combustion chamber 15 wherein the energy released during combustion of the fuel-air mixture via the piston 20 and the connecting rod 34 the crankshaft 40 put in a rotation. During combustion of the fuel-air mixture creates an exhaust gas, which through the piston 20 in a next step over the outlet 13 in the exhaust duct 51 is ejected. By a translatory movement of the piston 20 in the cylinder 18 not just the air in the combustion chamber 15 compressed, but parallel to the compression of the combustion chamber 15 will be in this cylinder 18 one with the crankcase 30 connected fluid volume increases, causing the pressure in the crankcase 30 decreases. This physical effect is used to crank the crankcase 30 as an "air pump" for the introduction of so-called "secondary air" in the exhaust duct 51 the internal combustion engine 10 to use. In a compression phase of the internal combustion engine 10 the piston moves 20 away from the crankshaft 40 , creating a volume in the crankcase 30 is enlarged. The pressure in the crankcase drops 30 under a pressure in the intake duct 14 , allowing air through the inlet valve 38 from the intake channel 14 over the line 16 in the crankcase 30 can flow in. The inlet valve 38 is designed as a pressure-controlled valve, which at a, in particular by a spring force of a valve spring, set pressure difference between the pressure in the crankcase 30 and the pressure in the intake passage 14 opens. The over the inlet valve 38 in the crankcase 30 inflowing air is caused by a downward movement of the piston 20 compacted, with the pressure in the crankcase 30 about the pressure in the intake duct 14 rises and the inlet valve 38 closes. By the further downward movement of the piston 20 the pressure in the crankcase increases 30 continue, with a gas exchange between the combustion chamber 25 and the crankcase through the piston 20 and the piston rings 35 is suppressed as far as possible to leakage losses. If a fixed pressure threshold is exceeded, the outlet valve opens 39 on the crankcase 30 so that the air from the crankcase 30 over the bypass line 33 in the exhaust duct 51 the internal combustion engine 10 flows. The introduction of the air into the exhaust duct 51 takes place between the outlet 13 the internal combustion engine 10 and the oxidation catalyst 52 to react by an exothermic reaction of the air with unburned hydrocarbons in the exhaust duct 51 the temperature of an exhaust gas of the internal combustion engine 10 before entry into the oxidation catalyst 52 to increase, for example, the oxidation catalyst 52 in a cold start phase to bring faster to operating temperature.

Alternatively, the devices 52 . 54 . 56 be arranged for exhaust aftertreatment in a different order. Also alternatively, one or two of the three described devices for exhaust aftertreatment can be omitted, also the use of a so-called "three-way catalyst" instead of an oxidation catalyst is possible, especially if the internal combustion engine 10 is designed as gasoline engine or gas engine. Also alternatively, it is provided that the bypass line 33 at another location, especially in front of the particulate filter 54 , in the exhaust duct 51 opens to the introduction of the secondary air inlet temperature of the exhaust gas when entering the particulate filter 54 , in particular for the regeneration of the particulate filter 54 to raise. It is also envisaged that the bypass line 33 forks and in several places in the exhaust duct 51 empties.

In 2 a further embodiment of a combustion arrangement according to the invention is shown. The internal combustion engine 10 is designed as a single-cylinder reciprocating engine. The exhaust system 50 includes dosing agent 70 , wherein the dosing agent 70 at the bypass line 33 arranged and via a metering valve 72 with the bypass line 33 are connected. The dosing agents 70 are over a line 82 with subsidies 60 connected, where the funding 60 over another line 81 with a storage container 80 for the fluid to assist the exhaust aftertreatment of the internal combustion engine 10 are connected. On the crankcase 30 is another exit 32 formed, taking on the output 32 an outlet channel 36 followed. In the exhaust duct 36 is a turbine 66 arranged, which over a wave 24 with a conveying element 26 the funding 60 connected is.

About the funding 60 is the fluid for supporting the exhaust aftertreatment from the reservoir 80 the dosing agents 70 fed and via the metering valve 72 in the bypass line 33 metered. In the bypass line 33 There is a mixing of the fluid and the gas from the crankcase 30 , resulting in a more even distribution of the fluid across the cross section of the bypass line 33 leads. The funding 60 be through the compressed gas from the crankcase 30 driven. In this case, the drive of the conveyor takes place 60 over the turbine 66 in the outlet channel 36 of the crankcase 30 , That from the crankcase 30 escaping gas drives the turbine 66 which, in turn, over the wave 24 the conveying element 26 in the funding 60 drives.

Alternatively, the dosing agents 70 also on the exhaust duct 51 be arranged. It is possible to use the fluid in the dosing agents 70 instead of a metering valve 72 over a carburetor 74 the bypass line 33 or the exhaust duct 51 supply. Alternatively, it is possible that the funding 60 be driven by an external drive, such as a drive belt or an electric motor.

In 3 is another embodiment of a combustion arrangement according to the invention with an internal combustion engine 10 shown. On the crankcase 30 are in addition to the embodiment according to 1 funding 60 arranged, which in this embodiment, a diaphragm pump 62 include. The diaphragm pump 62 has a housing 68 on which a membrane 63 is attached. In the case 68 is a pump room 66 formed, which via a suction valve 64 and a pressure valve 65 is closable. The diaphragm pump 62 is over an opening 69 in the case 68 fluidic with the crankcase 30 connected. Furthermore, the diaphragm pump 62 via a first line 81 with a storage container 80 for a tool to support the exhaust aftertreatment and another line 82 with the dosing agents 70 which is a metering valve 72 include, connected. The dosing agents 70 are at the exhaust duct 51 between a particle filter 54 and a catalyst 56 arranged for the selective reduction of nitrogen oxides.

By the oscillating movement of the piston 20 in the cylinder 18 the gas is in the crankcase 30 cyclic, synchronous to the engine speed or speed of the crankshaft 40 compressed and expanded, with a volume of gas in the crankcase 30 changes in a designed as a single-cylinder engine reciprocating engine during a stroke to the entire displacement of the reciprocating engine. This occurs in the crankcase 30 Pressure fluctuations, which affect the membrane 63 the diaphragm pump 62 act and thus in a pump room 66 the diaphragm pump 62 generate a negative pressure or overpressure cyclically. At negative pressure, the fluid flows to support the exhaust aftertreatment from the reservoir 80 over the line 81 through the suction valve 64 in the pump room 66 the diaphragm pump 62 , wherein the fluid at positive pressure in the delivery chamber 66 over the line 82 to the dosing agents 70 is encouraged. An air supply of the crankcase 30 can be omitted in this embodiment. Alternatively, it is provided that the crankcase 30 analogous to the comments on 1 is supplied with air and serves to generate pressure, wherein the pressurized air in the crankcase 30 can be used to the dosing 70 to cool. By cooling the dosing agent 70 becomes an aging, Crystallization, decomposition or vapor bubble formation of the fluid prevents or at least slows down. Furthermore, the risk of thermal damage to the dosing 70 reduced, especially if an arrangement of the dosing 70 directly on the exhaust duct 51 from spatial restrictions can not be avoided. In addition, it is alternatively provided that the fluid in the dosing 70 through the crankcase 30 pressurized air is atomized. For the purpose of cooling or atomization is a bypass line 33 from the crankcase 30 to the dosing agent 70 guided. Alternatively, for some fluids metering of the fluid also via a carburetor 74 take place, which instead of the metering valve 72 at the exhaust duct 51 or at the bypass line 33 is positioned. For example, fuels, in particular for raising an exhaust gas temperature, regeneration means for a particle filter or fluids which cause a reduction of pollutants in the exhaust gas, for example an aqueous urea solution for the reduction of nitrogen oxides, can be used as the fluid.

4 shows a further embodiment of a combustion arrangement according to the invention, wherein the dosing 70 in the bypass line 33 are arranged. The dosing agents 70 are by footbridges 84 containing the dosing agents 70 in the middle of the bypass line 70 position, fixed. The dosing agents 70 are over a line 82 with subsidies 60 connected, where the funding 60 over another line 81 with a storage container 80 are connected for the fluid. The drive of the conveyor 60 takes place in this embodiment via an additional drive source, for example, electrically, hydraulically, pneumatically or mechanically, in particular via a not shown belt drive, with the internal combustion engine 10 connected is. The fluid is through the conveyor 60 to the dosing agents 70 promoted and from there via the metering valve 72 in the bypass line 33 metered. In the process, the dosing agents become 70 through the compressed gas from the crankcase 30 which is via the outlet valve 39 in the bypass line 33 and there to the dosing agent 70 flowed past, cooled. Alternatively, the dosing agents 70 also on or in a wall of the bypass line 33 be arranged so that the dosing 70 only partially covered by the bypass line. In addition to the illustrated fixation on the webs 84 is also a fixation on a clamp body or a different type of fixation of the dosing 70 in the bypass channel 33 possible. It is also possible that the dosing 70 in the mouth area of the bypass line 33 in the exhaust duct 51 are arranged, wherein the metering valve 72 the fluid directly into the exhaust duct 51 dosed.

In 5 a further embodiment of a combustion arrangement according to the invention is shown, wherein the internal combustion engine 10 designed as a two-cylinder Boxer engine. The pistons 20 the two cylinders 18 Both are on the crankshaft 40 fixed, with the crankshaft 40 in a common crankcase 30 for both cylinders 18 is arranged. There is a power transmission of the two pistons 20 of the two-cylinder engine on a crankshaft 40 which are in a common crankcase 30 is arranged. at 2 Cylinder-boxer engines are caused by the opposite movement of the pistons 20 the boxer engine to correspondingly strong pressure fluctuations in the crankcase 30 , so that these pressure fluctuations or the pressure due to the compression of the gas in the crankcase 30 can be used efficiently. On the crankcase 30 are funding 60 arranged, with the funding 60 over a line 81 with a storage container 80 and another line 82 with a bypass line 33 connected, which from the crankcase 30 to the exhaust duct 51 leads. By an opposite movement of the cylinder 11 the boxer engine becomes the volume of the crankcase 30 each by the displacement of both cylinders 11 enlarged, or reduced. As a result, it is possible to achieve a significantly higher pumping line compared to a single-cylinder engine. The pressure in the crankcase 30 can also drive directly to the conveyor 60 be used, for example, by the expansion of the compressed air a turbine 66 drives, which in turn the funding 60 , in particular a pump, drives. About the funding 60 For example, the fluid is added to the dosing agents to aid exhaust aftertreatment 70 promoted, which, for example, a carburetor 74 or a metering valve 72 include.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19961947 [0002]
• DE 102005034704 [0002]
• DE 69522311 [0003]

Claims (10)

Combustion arrangement with an internal combustion engine ( 10 ) and one with the internal combustion engine ( 10 ) connected exhaust system ( 50 ), the exhaust system ( 50 ) an exhaust duct ( 51 ) for discharging an exhaust gas of the internal combustion engine ( 10 ) and a device for the aftertreatment of the exhaust gas, wherein the device for the aftertreatment of the exhaust gas on the exhaust gas duct ( 51 ), and wherein the internal combustion engine ( 10 ) a combustion chamber ( 15 ), which by a piston ( 20 ) is limited, and wherein the piston ( 20 ) on a combustion chamber ( 15 ) facing away from a crankcase ( 30 ), and wherein the crankcase ( 30 ) is arranged such that as a result of movement of the piston ( 20 ) a gas, in particular air, in the crankcase ( 30 ), characterized in that the crankcase ( 30 ) in such a way with the exhaust system ( 50 ), that in the crankcase ( 30 ) compressed gas of the exhaust system ( 50 ) can be supplied. Combustion arrangement according to claim 1, characterized in that the piston ( 20 ) movable in a cylinder ( 18 ) is arranged, wherein the piston ( 20 ) the combustion chamber ( 15 ) and the crankcase ( 30 ) except for leakage losses between the piston ( 20 ) and the cylinder ( 18 ), fluid-tightly separated from each other. Combustion arrangement according to claim 1 or 2, characterized in that the exhaust system ( 50 ) Grants ( 60 ) and / or dosing agent ( 70 ), which contains a fluid, in particular a fluid for exhaust aftertreatment, into the exhaust gas duct (FIG. 51 ). Combustion arrangement according to one of claims 1 to 3, characterized in that the crankcase ( 30 ) via a bypass line ( 33 ) with the exhaust duct ( 51 ) of the exhaust system ( 50 ) connected is. Combustion arrangement according to claim 3 or 4, characterized in that the conveying means ( 60 ) by the compressed gas from the crankcase ( 30 ) are driven. Combustion arrangement according to claim 3 or 4, characterized in that the piston ( 20 ) in the crankcase ( 30 ) compressed gas generates pressure fluctuations, wherein the pressure fluctuations the conveying means ( 60 ) of the exhaust system ( 50 ) for conveying the fluid into the exhaust gas duct ( 51 ) of the internal combustion engine ( 10 ). Combustion arrangement according to one of claims 3, 5 or 6, characterized in that the conveying means ( 60 ) a diaphragm pump ( 62 ). Combustion arrangement according to claim 3 and 4, characterized in that the exhaust system ( 50 ) at least dosing agent ( 70 ), the dosing agents ( 70 ) on the bypass line ( 33 ) are arranged. Combustion arrangement according to Claims 3 and 4, characterized in that the dosing means ( 70 ), at least partially, from the bypass line ( 33 ), wherein the dosing agents ( 70 ) by the in the crankcase ( 30 ) and through the bypass line ( 33 ) flowing gas to be cooled. Method for operating a combustion arrangement with an internal combustion engine ( 10 ) and one with the internal combustion engine ( 10 ) connected exhaust system ( 50 ), wherein an exhaust gas of the internal combustion engine ( 10 ) of the exhaust system ( 50 ), which an exhaust duct ( 51 ) and a device for aftertreatment of the exhaust gas, is supplied, wherein the device for the aftertreatment of the exhaust gas at the exhaust duct ( 51 ), wherein a combustion chamber ( 15 ) of the internal combustion engine ( 10 ) by a piston ( 20 ), and wherein a crankcase ( 30 ) by a the combustion chamber ( 15 ) side facing away from the piston ( 20 ), and wherein a gas, in particular air, by a movement of the piston ( 20 ) in the crankcase ( 30 ), characterized in that the crankcase ( 30 ) in such a way with the exhaust system ( 50 ), that in the crankcase ( 30 ) compressed gas of the exhaust system ( 50 ) is supplied.

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