EP2151569A1 - Device for removing a waste gas partial stream and combustion engine with this device - Google Patents

Abstract

The device has an exhaust gas removing channel (106) flowing into an exhaust pipe (105) of an internal combustion engine. An annular passage (120) is arranged directly after a valve disk (101) in a flow direction of exhaust gas, such that an exhaust gas partial flow arrives into the passage using dynamic pressure of the exhaust gas. A valve (130) is provided in the channel, and the passage is arranged in a partial cross sectional region of the exhaust pipe. An inner contour of the channel forms a diffuser in the passage. An independent claim is also included for an internal combustion engine including an auxiliary device connected to a turbine.

Description

The present invention relates to a device for taking a partial exhaust gas stream and an internal combustion engine with this device. In particular, the present invention relates to a device for taking a partial exhaust gas stream from an exhaust pipe of an internal combustion engine and to an internal combustion engine with an exhaust gas recirculation system.

In internal combustion engines, exhaust gas recirculation is used to reduce the amount of nitrogen oxide (NOx) emissions. The exhaust gas recirculation includes a removal of a partial exhaust gas flow from an exhaust pipe of the internal combustion engine and a return of this partial flow in the intake passage of the internal combustion engine. The introduced into the inlet of the internal combustion engine exhaust gas acts as an inert gas, which reduces the oxidation of nitrogen to nitrogen oxides.

To achieve a flow of the partial exhaust gas flow certain pressure conditions must be present. In particular, a basic condition is that the pressure of the exhaust gas substream at the position of the inlet is at least as great as the pressure of the air flowing in the inlet passage. To overcome flow resistance and to improve the response of the exhaust gas recirculation control should However, the pressure of the exhaust gas partial stream to be a degree higher than that in the inlet passage.

In internal combustion engines, referred to as naturally aspirated engines, the pressure in the inlet passage is reduced from the ambient pressure. Further, the pressure of the exhaust gas at the outlet passage is increased from the ambient pressure. Thus, in the suction engines mentioned, by establishing a connection and controlling a valve in this connection, the partial exhaust gas flow may be introduced into the intake passage.

However, there are known engine systems in which the pressure in the inlet passage is increased from the ambient pressure. These internal combustion engines include, for example, two-stroke internal combustion engines, in particular two-stroke diesel engines, as well as all supercharged by means of a turbocharger or compressor internal combustion engine. In such internal combustion engines, there is a pressure ratio between the pressure at the inlet passage and the pressure at the outlet passage, which makes flow based on the pressure difference impossible from the outlet passage to the inlet passage. For this purpose, various technologies for introducing the exhaust gas partial flow into the inlet passage are known in the prior art. In particular, blowers or compressors are used to increase the pressure of the exhaust gas partial flow over those in the inlet passage.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a device for taking a partial exhaust gas stream from an exhaust pipe of an internal combustion engine, with which the exhaust gas partial stream with simple means in the Inlet passage of an internal combustion engine can be initiated. In particular, it is the object of the present invention to provide an internal combustion engine with an exhaust gas recirculation system, which can overcome the problem of the aforementioned unfavorable pressure ratios of outlet passage and inlet passage by simple means. Moreover, it is the object of the present invention to provide an internal combustion engine, which advantageously uses the device for taking a partial exhaust gas stream.

The object is achieved by a device for taking a partial exhaust gas stream from an exhaust pipe of an internal combustion engine according to claim 1. Furthermore, the object is achieved by an internal combustion engine according to claim 27, 30 or 33. Advantageous developments of the invention are defined in the dependent claims.

According to a first aspect of the present invention, a device is provided for removing an exhaust gas partial stream from an exhaust line of an internal combustion engine having a partial exhaust gas line which opens into the exhaust gas line, the input area of which is arranged substantially opposite to the exhaust gas flow, so that the exhaust gas partial flow is utilized by utilizing the dynamic pressure of the exhaust gas flow Exhaust gas flow can enter the opening of the partial exhaust gas line.

According to a preferred embodiment of the present invention, the input region is arranged in a partial cross-sectional region of the exhaust gas line, in which at least in a predetermined operating range of the internal combustion engine over the partial cross-section averaged flow velocity of the exhaust gas flow is higher than a over the total cross section averaged flow velocity of the total exhaust gas flow is.

According to a preferred embodiment of the present invention, the input region of the partial exhaust gas line is arranged in the direction of flow immediately after a flow control member.

According to a preferred embodiment of the present invention, the input region is arranged in a region of the exhaust pipe in which flow velocity peaks occur in the course of an opening operation of the flow control member, at least in a predetermined operating region of the internal combustion engine.

According to a preferred embodiment of the present invention, the pressure in the partial exhaust gas line is at least in a predetermined operating range of the internal combustion engine higher than the pressure in the exhaust gas line without removal of the partial exhaust gas flow at removal of the partial exhaust gas stream.

According to a preferred embodiment of the present invention, the flow control member is an exhaust valve of the internal combustion engine.

According to a preferred embodiment of the present invention, the flow control member is designed as a poppet valve with a valve disk and a valve stem, wherein the valve stem is encompassed by the input region of the partial exhaust gas line.

According to a preferred embodiment of the present invention, the partial exhaust gas line and / or the Entrance of the partial exhaust gas line arranged coaxially in the exhaust pipe.

According to a preferred embodiment of the present invention forms an inner contour of the partial exhaust gas line in the region of the input area a diffuser.

According to a preferred embodiment of the present invention, the partial exhaust gas line is formed in the region of the input region as a pitot tube.

According to a preferred embodiment of the present invention, the partial exhaust gas line is provided with a flow control device with which the flow in the partial exhaust gas line is controlled.

According to a preferred embodiment of the present invention, the flow in the partial exhaust gas line is controlled by the flow control device in dependence on the flow characteristic in the exhaust gas line and / or on the operating state of the internal combustion engine.

According to a preferred embodiment of the present invention, the flow control device is a valve provided in the partial exhaust gas line which is actuated to allow and inhibit the flow between the partial exhaust gas line and the exhaust gas line.

According to a preferred embodiment of the present invention, the flow control device is a poppet valve operable by a cam mechanism.

According to a preferred embodiment of the present invention, the flow control device is a Rotary valve disposed on the valve stem of the exhaust valve.

According to a preferred embodiment of the present invention, the rotary valve has a fixed ring member and a coaxially arranged rotatable ring member having corresponding openings, wherein by rotating the rotatable ring member relative to the fixed ring member, a flow through the openings is permitted or inhibited.

According to a preferred embodiment of the present invention, the fixed ring member is attached to the input portion of the partial exhaust gas passage and the rotary ring member is attached to the valve stem so that the rotary ring member is rotatable by rotating the valve stem relative to the stationary ring member.

According to a preferred embodiment of the present invention, the flow control means is constructed of a valve seat provided at the input portion of the partial exhaust gas line and a valve body slidable coaxially with the valve stem of the flow control member, the valve body being engageable against and lifted off the valve seat around the input portion of the partial exhaust gas line to close or open.

According to a preferred embodiment of the present invention, the valve body is located downstream of the inlet region of the partial exhaust gas line in the flow direction of the partial exhaust gas flow.

According to a preferred embodiment of the present invention, the flow control device is operable by an exhaust valve drive of the internal combustion engine.

According to a preferred embodiment of the present invention, the flow control means is operable in synchronism with the operation of the exhaust valve.

According to a preferred embodiment of the present invention, a throttle valve adjustable by a throttle valve actuator is provided in the exhaust pipe, with which a back pressure in the exhaust pipe is adjustable.

According to a preferred embodiment of the present invention, the throttle valve actuator is formed as a cam mechanism.

According to a preferred embodiment of the present invention, the throttle valve actuator and an actuator provided for the flow control device are kinematically coupled together.

According to a preferred embodiment of the present invention, the flow control device is kept closed in predetermined operating states of the internal combustion engine, in particular when a minimum speed of the internal combustion engine is undershot.

According to a preferred embodiment of the present invention, a check valve is provided in the partial exhaust gas line, which prevents a backflow to the input region of the partial exhaust gas line.

According to a second aspect of the present invention, there is provided an internal combustion engine having an apparatus according to the first aspect of the present invention, the partial exhaust gas passage of which is an exhaust gas recirculation line directly or indirectly connected to at least one combustion chamber of the internal combustion engine.

According to a preferred embodiment of the present invention, the internal combustion engine is a two-stroke diesel engine with purging air blower and / or turbocharging.

According to a preferred embodiment of the present invention, the internal combustion engine is a turbocharged four-stroke internal combustion engine.

According to a third aspect of the present invention, there is provided an internal combustion engine having an apparatus according to the first aspect of the present invention, wherein the partial exhaust gas passage is connected to a turbine of a turbocharger and / or an auxiliary device such that the turbocharger and / or the auxiliary device at least partially operated with the partial exhaust stream.

According to a preferred embodiment of the present invention, in the internal combustion engine according to the third aspect of the invention, the auxiliary device may optionally supply the power of the internal combustion engine generated by the turbine.

According to a preferred embodiment of the present invention, in the internal combustion engine according to the third aspect of the invention, the turbine over the power over to supply a gearbox to the crankshaft of the internal combustion engine.

According to a fourth aspect of the present invention, there is provided an internal combustion engine with an apparatus according to the first aspect of the present invention, further provided with a pressure-operated actuator operable with the partial exhaust gas flow taken by the exhaust partial exhaust apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail by means of exemplary embodiments on the basis of the following drawings, which show different embodiments of the invention.

Fig. 1 shows an exhaust gas recirculation system for an internal combustion engine, to which the device for taking a partial exhaust gas flow according to the invention is applicable.

Fig. 2 illustrates an exhaust valve in slightly open position with directly coupled annular slide according to a first embodiment, which relates to the exhaust gas recirculation system of Fig. 1 is applicable.

Fig. 3 illustrates the exhaust valve in the fully open position with directly coupled annular slide according to the first embodiment, which refers to the exhaust gas recirculation system of Fig. 1 is applicable.

Fig. 4 shows a development of the annular slide, which is used in the first embodiment.

Fig. 5 shows an exhaust valve with a coupling of the exhaust valve drive with a throttle device in the exhaust passage and a controlled exhaust valve for exhaust gas recirculation valve according to a second embodiment of the invention, which relates to the exhaust gas recirculation system of Fig. 1 is applicable.

Fig. 6 shows an exhaust valve with coaxial arrangement of the bleed valve in the exhaust passage according to a third embodiment of the invention, which relates to the exhaust gas recirculation system of Fig. 1 is applicable.

Fig. 7 shows one opposite to that of Fig. 1 modified internal combustion engine system, in which the device according to the invention is used to operate a low-pressure turbine.

Fig. 8 shows one opposite to that of Fig. 1 modified internal combustion engine system, in which the device according to the invention is used to operate an auxiliary device.

Fig. 9 shows one opposite to that of Fig. 1 modified internal combustion engine system in which the device according to the invention is used for driving a crankshaft of the internal combustion engine.

Fig. 10 shows one opposite to that of Fig. 1 modified internal combustion engine system, in which the device according to the invention is used to operate a pressure-actuated actuator.

PREFERRED EMBODIMENTS OF THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the description of the exemplary embodiments is intended to describe specific embodiments of the invention defined in the claims in more detail. Features of the individual embodiments may be meaningfully combined with each other, so that further embodiments of the present invention will be apparent to those skilled in the art which are within the scope of the claims.

EXPLANATION OF THE EXHAUST GAS RECYCLING SYSTEM

Fig. 1 schematically represents an exhaust gas recirculation system for an internal combustion engine. The exhaust gas recirculation system of Fig. 1 is exemplary applied to a two-stroke diesel engine with turbocharging.

The internal combustion engine shown here has a cylinder 2 and a piston 5, through which a combustion chamber 3 is limited. By the movement of the piston 5 within the cylinder 2, the working volume of the combustion chamber 3 is variable.

The piston 5 is connected to a crankshaft, not shown, via a piston rod, not shown. The movement of the piston 5 within the cylinder 2 is converted in known manner into a rotational movement of the crankshaft. Mechanical power generated by combustion of an air-fuel mixture is extracted via the crankshaft.

In the lower part of the cylinder 2 air inlet slots 4 are provided, which are swept over by the piston 5 during operation of the internal combustion engine. In this way, the Air inlet slots 4 of the cylinder 2 controlled as intake valves. Namely, once the piston 5 has reached a predetermined lower position, the air intake slots are opened so that air or an air-exhaust mixture can be introduced into the cylinder.

An injector, not shown, is arranged on the cylinder that can be introduced into the combustion chamber 3 by this fuel. Alternatively, several injectors with the same or different properties or controls can be provided.

At the top of the cylinder, an exhaust valve 1 is provided. This outlet valve 1 is designed as a poppet valve and in the FIGS. 2 to 5 shown in more detail. Although an exhaust valve is shown in the exemplary embodiments, it is also possible to provide a plurality of exhaust valves having the structure according to the invention. Alternatively, one or more conventional exhaust valves may be provided in addition to the one or more exhaust valves of the present invention.

The internal combustion engine further includes an intake manifold in the form of an intake manifold 8 and an exhaust manifold in the form of an exhaust manifold 9. The intake manifold 8 is connected to the air intake slots 4 via an intake passage 6. The exhaust manifold 9 is connected to the exhaust valve 1 via an exhaust passage 7 so that the combustion chamber 3 communicates with the exhaust manifold 9 through the exhaust passage 7 when the exhaust valve 1 is opened.

Exhaust gas in the exhaust manifold 9 is in the example shown here via an exhaust pipe element 24 a turbocharger 20 supplied. The turbocharger 20 operates in a known manner, so that the pressure at the inlet of the engine can be increased by means of the exhaust gas energy. The turbocharger 20 includes a turbine 21, a compressor 22, and a turbocharger shaft 23 connecting the turbine 21 and the compressor 22. Exhaust gas at a certain pressure, which is above the ambient pressure, is supplied via the exhaust pipe member 24 of the turbine 21. In the turbine 21, the exhaust gas is expanded, so that the energy contained is transmitted to the turbocharger shaft 23. The expanded exhaust gas is exhausted via an exhaust pipe member 27.

The power applied to the turbocharger shaft 23 is used to operate the compressor 22. This compresses intake air introduced via the intake pipe member 26 and discharges the compressed intake air via an intake pipe member 25.

A charge air cooler 28 is provided to cool the pressurized intake air whose temperature has been raised by the compression operation. As a result, an improvement of the degree of filling of the internal combustion engine is achieved. The cooled intake air is supplied to the intake manifold 8 through an inlet conduit member 29 and an inlet conduit member 17.

As indicated above, the pressure at the inlet of the internal combustion engine is increased by the turbocharger 20. However, the pressure may be increased without a turbocharger 20 by using a blower, not shown, which is driven by an electric motor or the power applied to the crankshaft. In any case, in this two-stroke diesel internal combustion engine, the pressure at the inlet, in particular at the air inlet slots 4 increases relative to the ambient pressure, so that there is a good rinse efficiency, so that the burned mixture can be sufficiently replaced by fresh air / fresh gas.

The exhaust gas recirculation system for the internal combustion engine has an exhaust gas recirculation line, which consists of exhaust partial flow line elements 12, 13, 14 and 16. In the region of the exhaust valve 1, an exhaust partial flow is withdrawn and introduced into the exhaust partial flow line element 12. Downstream of the exhaust partial flow line member 12, a recirculation gas collecting pipe 10 is provided. From this manifold, the exhaust partial flow conduit member 13 leads to a recirculation gas cooler 11, which cools the recirculated exhaust gas. The recirculation gas is passed through the exhaust partial flow conduit member 14 to a check valve 15 which prevents the recirculation gas from flowing back in the direction of the exhaust valve. It should be noted that the check valve 15 is not mandatory and can be omitted.

From the check valve 15, the recirculation gas is guided via the exhaust partial flow passage member 16 to a connection point between the inlet passage members 17 and 29, which guide the compressed intake gas to the intake manifold 8.

In addition or as an alternative to the check valve 15, a check valve 15a may be provided in the exhaust partial flow line element 12 in front of the recirculation gas collection tube 10. This check valve 15a is preferably used in an internal combustion engine having a plurality of cylinders to reverse flow the exhausted in a cylinder Prevent exhaust gas flow through the recirculation manifold 10 into another cylinder. It should be noted that the check valve 15a is also not mandatory and may be omitted especially in an internal combustion engine with only one cylinder.

In addition, both the check valve 15 and the check valve 15a can be replaced by an actively controlled valve, which can be actuated for example by a mechanical or electromagnetic actuator with an optimized timing.

Using the exhaust gas sampling device of the present invention explained later, the pressure of the exhaust gas introduced into the exhaust gas partial flow passage member 16 at the aforementioned connection point between the inlet conduit members 17 and 29 is higher than the pressure of the inlet gas directed in the inlet conduit member 29 to the connection point. Thus, the partial exhaust stream taken at the exhaust valve 1 can be introduced into the intake manifold 8 of the internal combustion engine.

In the following, embodiments of the exhaust valve 1 are shown, which has a device for taking a partial exhaust gas stream from the exhaust pipe of the internal combustion engine. The special embodiment of this device removal of the partial exhaust gas flow allows the introduction of the partial exhaust gas flow into the intake manifold 8 of the in Fig. 1 illustrated system, as explained above.

Furthermore, this device for removing the partial exhaust gas stream in the in the Figures 7-10 illustrated internal combustion engine systems applicable.

FIRST EMBODIMENT

Fig. 2 shows the exhaust valve in a slightly open position with directly coupled annular slide according to the first embodiment, the exhaust gas recirculation system of Fig. 1 is applicable.

The exhaust valve 1 is a so-called poppet valve which has a valve disk 101 and a valve stem 102. The valve stem 102 is mounted translationally and rotatably movable in a bearing bush 103. The bushing 103 is inserted into a bore in a cylinder head 111, for example by pressing.

The circular valve disk 101 cooperates with a valve seat 104 so that upon contact of the valve disk 101 with the valve seat 104, flow through the exhaust valve 1, in particular through a radial gap between the valve disk 101 and the valve seat 104, is prevented and the exhaust valve 1 is closed.

To open the exhaust valve 1, the valve stem 102 is actuated axially with an actuating mechanism, not shown, such as a camshaft with bucket tappets, rocker arms or a hydraulic device, so that the valve plate 101 from the valve seat 104 against the bias by a valve spring, not shown, such as a Air spring takes off. However, the actuation of the exhaust valve 1 can be done in any way, as long as the actual function of the exhaust valve 1 is ensured. Exhaust gas in the combustion chamber 3 can thus flow through the resulting annular gap between the valve disk 101 and the valve seat 104. In this position, the exhaust valve is open.

In the cylinder head 111, an outlet chamber 105 is provided adjacent to the valve seat 104. This discharge chamber 105 provides a space through which the exhaust gas flowing through the opened exhaust valve 1 can pass. The outlet chamber 105 is provided with a in Fig. 1 illustrated outlet passage 7 connected. Thus, with the exhaust valve 1 open, the exhaust gas can enter the exhaust passage 7 through the exhaust chamber 105.

In the following, the particular embodiment of the exhaust valve 1 will be described, which enables the removal of the exhaust gas partial flow according to the invention. Coaxially disposed about the valve stem 102, an exhaust gas removal passage 106 is provided. This exhaust gas removal passage 106 has an annular gap 120 formed between an outer coaxial element 112 and an inner coaxial element 113 of the cylinder head 111. The inner coaxial element 113 is simultaneously provided for supporting the bearing bush 103 for the valve stem 102. The annular gap 120 formed between the elements 112 and 113 continues into the exhaust gas removal passage 106. At the lower end, in particular the end of the elements 112 and 113, which face the valve disk 101, a tube 107 is provided. This tube 107 is attached to the outer coaxial element 112 so that the tube 107 forms an axial extension of the coaxial element 112 and at the same time the entrance region of the flue-withdrawal passage 106. At the lower end of the tube 107, a rotary valve 130 is formed, which can open and close a gap between the tube 107 and the outer periphery of the valve stem 102. This rotary valve 130 will be described in more detail below.

Provided on the valve stem 102 in the region of the lower end of the tube 107 is an enlarged diameter section, which is referred to below as the actuating section 108. At this operating portion 108, an inner annular gap sleeve 110 is attached. Axially outside the actuating portion 108, an outer annular gap sleeve 109 is provided, which is attached to the inner coaxial element 113. The inner annular gap sleeve 110 can be rotated with the valve stem 102 relative to the outer annular gap sleeve 110.

Fig. 4 shows a development of the outer annular gap sleeve 109 and the inner annular gap sleeve 110 in plan view and sectional view. Here, the construction of the sleeves with superimposed and relative to each other slidable slots can be seen, the function of which will be explained in more detail below.

The rotation, and in particular the targeted rotation of the valve stem 102 is used by a mechanism provided for this purpose, which is already provided in such internal combustion engines to reduce shrinkage of the valve seats and to improve the lubrication of the valve stems.

The annular gap sleeves 110 and 109 have complementary slots or openings, which allow a passage of exhaust gas when the slots or openings of both annular gap sleeves 110 and 109 are superimposed. Upon rotation of the annular gap sleeves 110 and 109, the passage is interrupted.

Thus, a rotary slide valve 130 is formed in the annular gap between the tube 107 and the valve stem 102, which can be opened and closed with the rotation of the valve stem 102.

The function of the exhaust valve 1 according to the first embodiment of the present invention will be described with reference to FIGS Figures 2-4 described in more detail.

At the end of the combustion stroke of the two-stroke diesel internal combustion engine, the exhaust valve 1 is opened in a known manner, so that the exhaust gas can be discharged from the combustion chamber 3 via the exhaust chamber 105 and the exhaust passage 7. This position is in Fig. 1 shown. Shortly before opening the exhaust valve 1, the combustion chamber 3 is still at a relatively high pressure, so that by the slight opening of the exhaust valve 1 by lifting the valve disk 101 from the valve seat 104 exhaust flows at high speed through the resulting narrow annular gap.

In Fig. 2 the flow through the annular gap of the valve 1 is shown schematically shortly after the lifting of the valve disk 101 from the valve seat 104. It can be seen here that the flow of the exhaust gas through the annular gap of the valve 1 extends radially inwards in the direction of the valve stem 102. The concentration of the streamlines, taking into account the continuity equation, means an increased flow velocity, whereas in the radially outer region the flow velocity is low.

In this situation, shortly after the exhaust valve 1 is opened or the outlet valve 1 is still slightly open, the exhaust gas flows into the outlet chamber 105 and strikes the lower opening between the valve stem and the tube 107, namely In this case, in an optimized timing by rotation of the outlet valve 1, the annular slide 130 is opened so that the exhaust gas can enter the annular gap between the valve stem 102 and the tube 107. Due to the high speed with slight opening of the exhaust valve 1, the exhaust gas enters with open ring slide 130 without difficulty in the annular gap. In this case, the dynamic pressure of the exhaust gas is used, so that in the exhaust gas removal passage 106 results in calming the flow, an increased total pressure of the exhaust gas.

This results in the increase of the total pressure from the use of the dynamic pressure of the exhaust gas due to its high flow velocity. The specific arrangement of the inlet region of the exhaust gas removal passage 106 in a partial cross-sectional area of the discharge chamber 105 in which the partial flow cross-sectional flow velocity of the exhaust gas is higher than a flow rate averaged over the entire cross section of the discharge chamber 105 causes an increase in the total pressure of the exhaust gas taken as the partial exhaust gas stream can be.

It is particularly advantageous if the input area of the exhaust gas removal passage 106 is opened only in the time interval in which an increase in the total pressure using the dynamic pressure is even possible. It has been found that when the outlet valve 1 is slightly open, ie when the outflow of exhaust gas begins from the annular gap between the valve disk 101 and the valve seat 104, the afore-indicated averaged pressure ratios in the cross-sectional areas in the outlet chamber 105 increase the total pressure in the exhaust gas removal passage 106 enable. Therefore, only in this time interval, the annular slide 130 is opened and otherwise kept closed, as will be discussed below.

In Fig. 3 the exhaust valve 1 is shown in the open position. In this case, the annular gap between the valve disk 101 and the valve seat 104 is increased, so that the flow velocity is reduced on the one hand due to the large cross-section of the annular gap, on the other hand due to the previously occurred relaxation of the exhaust gas in the combustion chamber, as is clear by the flow lines shown schematically. In this situation, the dynamic pressure of the exhaust gas can not increase the total pressure in the exhaust gas exhaust passage. Therefore, in this position, by turning the valve stem, the sleeve valve is closed and the main part of the exhaust gas exits through the outlet passage 7.

By optimizing the size ratios of the annular gaps as well as the timing of the valve opening and the operation of the annular gap by turning the valve stem 102, the total pressure in the exhaust gas removal passage 106 is increased so that the introduction of the exhaust gas partial flow into the intake manifold passage 8 is possible because the sufficient pressure difference with respect to the Pressure is present in the inlet manifold 8.

SECOND EMBODIMENT

Fig. 5 is a schematic representation of an exhaust valve 1 with coupling of the valve drive with a throttle device in the exhaust passage 7 and a controlled exhaust valve for exhaust gas recirculation according to the second embodiment of the invention.

The exhaust valve 1 according to the present second embodiment has a valve disk 201 and a valve stem 202. Likewise, in the exhaust valve 1 of the second embodiment, a tube 207 is provided which in Fig. 5 is shown only schematically. The bearing of the valve shaft 202 and the coaxial arrangement of inner and outer coaxial elements of the cylinder head 211 are similar to those in the first embodiment.

The difference from the first exemplary embodiment lies in the control of the exhaust gas flow through the exhaust gas removal passage 206.

Downstream of the annular gap between the valve stem 202 and tube 207, through which the partial exhaust gas stream enters the tube 207, a poppet valve 230 is provided, which has a valve plate 209 and a valve seat 210 which is provided at the Abgasentnahendurchurchgang 206. The valve disk 209 can be pressed against the valve seat 210 by means of a spring 208b, so that the exhaust gas removal passage 206 is closed. A rocker arm 208a is provided which is associated with a valve stem 209a of the bleed valve 230.

Thus, by the rocker arm 208a, the valve disk 209 can be lifted off the valve seat 210, so that the connection between the exhaust gas removal passage 206 and the in Fig. 1 shown return gas line element 12 is produced. The rocker arm 208a is actuated with a cam 208c which is connected via a power transmission element, such. B. a chain 208 d is driven. This power transmission element is connected to the camshaft 208e of the internal combustion engine that actuates the exhaust valve 1, either directly or via another gear mechanism so that the exhaust sampling valve 230 is opened and closed in accordance with the operation of the camshaft 208e.

The operation of the exhaust valve 1 of the second embodiment is similar to that of the first embodiment. With slight opening of the exhaust valve 1, if there is a slight annular gap between the valve disk 201 and the valve seat 204, the exhaust flows at high speed into the tube 207, in which case the exhaust valve 230 is opened by operation coupled to the camshaft 208e , As the exhaust valve 1 is opened further, the exhaust valve 230 is closed again, so that the increased dynamic pressure at slight opening of the exhaust valve 1 in the exhaust stroke of the internal combustion engine can be used to increase the total pressure in the exhaust exhaust passage 206. Furthermore, by closing the exhaust gas removal valve 230, a back flow of the exhaust gas partial flow is prevented.

In the following, a development of the second embodiment will be described.

According to this development, this is in Fig. 5 shown throttle valve 215 is provided. This throttle valve 215 is formed in this development as a flapper valve, which is rotatably disposed within the outlet passage 7 or alternatively at another location in the outlet. A transmission element 216, such as. As a chain or a belt is connected to the camshaft 208e directly or via another transmission mechanism.

The operation of this modification will be described with reference to FIG Fig. 5 described.

When opening the exhaust valve 1, the exhaust gas flow enters the tube 207 and the outlet chamber 205. Shortly after opening the exhaust valve 1, in this modification, the throttle valve 215 is closed, so that the passage between the exhaust chamber 205 and the exhaust passage 7 is throttled. Thus, an increased back pressure is formed in the outlet chamber 205, so that with an optimized timing, a further increased pressure in the tube 207 can be provided.

Upon further opening of the exhaust valve 1, the throttle valve 215 is re-opened in conjunction with the actuation via the transmission element 216 and the camshaft 208e, so that a reduced, d. H. gives normal flow resistance in the outlet channel, so that a sufficient fresh gas purging can be made.

THIRD EMBODIMENT

A third embodiment of the invention will be described with reference to FIG Fig. 6 described. Fig. 6 shows an exhaust valve 1 with coaxial arrangement of the exhaust gas recirculation valve 330 in the annular gap according to the third embodiment of the invention.

The exhaust valve 1 according to the third embodiment has a valve disk 301, a valve seat 304 and a valve stem 302. An annular gap between an outer coaxial element 312 and an inner coaxial element 313 is also provided in this embodiment. The tube 307 is open as in the other embodiments down and has at the Inside a valve seat 309 which is closable with the valve element 308. Valve member 308 is slidably mounted longitudinally on valve stem 302 and may be moved axially by an unillustrated actuating mechanism, regardless of movement of valve stem 302, such that a valve face 310 may be brought into abutment with valve seat 309 to close valve 330 ,

With slight opening of the exhaust valve 1, namely with slight lifting of the valve plate 302 from the valve seat 304, the valve surface 310 of the valve member 308 is lifted by the actuating mechanism of the valve seat 309. Upon further opening of the outlet valve 1, namely upon enlargement of the annular gap between the valve disk 301 and the valve seat 304, the valve element 308 is approximated to the valve seat 309. With a predetermined kinematic adjustment, the valve face 310 is brought into abutment against the valve seat 309 when a predetermined opening degree of the exhaust valve is exceeded. Thus, in this embodiment, it is possible by simple means to introduce the exhaust gas flow through the annular gap between the valve disk 301 and the valve seat 304 in the input area, when there is a slight opening of the exhaust valve. Upon enlargement of the opening of the exhaust valve, the exhaust gas recirculation valve 330 is closed by the valve element 308 and the valve seat 309 provided on the inside of the tube 307, so that the exhaust gas flows exclusively through the exhaust passage 7.

Even with the exhaust valve 1 of the third embodiment is made possible, the dynamic pressure increase of the exhaust gas partial stream by timed Opening the Abgasentnahendurchurchgangs performed by the exhaust gas removal valve 330.

Variations of the Embodiments

In the illustration of the invention described above, the exhaust valve with the device for taking a partial exhaust gas stream is shown on a two-stroke diesel engine with exhaust gas recirculation and charging by a turbocharger. The application of the device according to the invention for the removal of a partial exhaust gas stream is particularly effective in this application. However, the exhaust partial exhaust flow device may also be effectively applied to other constructions as described below with reference to FIGS Figures 7-10 being represented.

Fig. 7 represents an internal combustion engine, which is designed as a two-stroke diesel internal combustion engine. The construction of the internal combustion engine is opposite to that of Fig. 1 unchanged. In particular, the internal combustion engine has a piston 5, air inlet slots 4, a cylinder 2 and a combustion chamber 3 located in the cylinder 2. Further, an exhaust valve 1 is provided, which is formed according to the embodiments discussed above. The internal combustion engine also has a turbocharger 20, which consists of a compressor 22 and a turbocharger shaft 23 and in contrast to the system of Fig. 1 a low pressure turbine 21a and a high pressure turbine 21b.

According to the present application of the device for removing the partial exhaust gas flow, the line element is still with the exhaust gas removal passage 106, 206, 306th connected, however, the exhaust partial flow is used in addition to the exhaust gas recirculation or exclusively to operate the high pressure turbine 21 b of the turbocharger 20. For this purpose, the in Fig. 1 shown exhaust gas cooler 11 omitted meaningful way. Alternatively, it is possible to design the turbine as a two- or multi-flow turbine in which different inlet pressures are provided. At this time, the main exhaust gas flow passing through the exhaust passage 7 may be introduced into a low pressure portion of the turbine 21, and the exhaust gas partial flow taken by the exhaust partial exhaust flow device having a higher pressure than the main exhaust gas flow may be supplied to the high pressure portion of the turbine 21. With this system, the efficiency of the turbine and thus the overall system can be improved.

Another application of the device for taking a partial exhaust gas stream according to the invention is in Fig. 8 shown. In this case, a turbogenerator 50 is provided as an auxiliary device which can use the partial exhaust gas flow to generate electrical energy. In the Fig. 8 shown internal combustion engine corresponds to in Fig. 1 illustrated internal combustion engine. In particular, a main exhaust gas flow is discharged through an outlet passage 7 and a partial exhaust gas flow via the line member 13, 14 of a turbine 51 without passage through the in Fig. 1 shown exhaust gas cooler 11 supplied. The partial exhaust gas stream is expanded in the turbine 51 and discharged via the passage 54. With the turbine 51, an electric generator 52 is connected via a shaft 53 in this embodiment. By a control device, not shown, the partial exhaust gas flow, which is guided to the turbine 51, are controlled, so that the corresponding electrical power can be tapped on the generator 52.

Alternatively, instead of the electric generator 52, any means may be provided which can be operated with the mechanical power of the turbine 51.

Another application of the device for taking a partial exhaust gas stream according to the invention is in Fig. 9 shown. The structure of this alternative application of the device for the removal of the exhaust gas partial stream is similar to that of the previous application. However, while in the previous application an auxiliary device is driven by the turbine 51, the power generated by the turbine 51 in this further application is used to assist the operation of the internal combustion engine. In particular, the output shaft 53 of the turbine 51 is connected via a transmission 55 to the crankshaft of the internal combustion engine and thus able to transmit the power to the crankshaft. In this application may also be provided a way to either transfer the power to the crankshaft or supply the turbo-generator, which in Fig. 8 is shown. For this purpose, a switching device is required, which can switch between the power transmission to the crankshaft and the power transmission to the generator 52.

Another application of the device for taking a partial exhaust gas stream according to the invention is in Fig. 10 shown. In this alternative application of the partial exhaust stream removal device, the partial exhaust stream taken from the exhaust removal passage may be used to actuate a gas pressure actuated actuator 60. Such an actuator 60 may For example, represent an actuator for actuating a valve or an adjusting mechanism of the turbocharger. In this case, the actuator 60 may be provided with a control valve for actuating a piston, not shown, which is driven for example by the central control for the internal combustion engine. Furthermore, an accumulator 70 can be switched in the flow direction in front of the actuator 60, so that on the one hand the pressure is constantly available and on the other hand pressure pulsations are reduced. By this alternative application, the internal combustion engine system can be improved so that, for example, a previously required compressed air generation or vacuum generation to actuate certain actuators is unnecessary. Overall, this improves the overall efficiency of the internal combustion engine system.

The present invention has been described with reference to the embodiments shown in the figures. While the return valve 1 is shown in the first embodiment with the annular gap sleeves 109 and 110, which are rotated by a rotational movement of the valve stem, this system can be supplemented by an actuating mechanism which is exemplified in Fig. 5 is shown. In particular, the kinematic coupling of the rotational movement of the valve stem 102 of the exhaust valve 1 of the first embodiment can be provided as in Fig. 5 is applied to the exhaust gas removal valve 230. Further, in all of the described embodiments, the throttle valve may be provided in the exhaust passage 7, which is kinematically coupled to the camshaft, as in FIG Fig. 5 already shown, or is actuated by a separate actuating mechanism.

The present invention relates to a device on an exhaust valve 1, which is described in application to a two-stroke diesel internal combustion engine. However, the exhaust valve 1 of the present invention is applicable to any internal combustion engine having an exhaust valve. For example, this exhaust valve may be used in a four-stroke internal combustion engine. The advantages of applying the exhaust valve 1 to a four-stroke internal combustion engine are particularly excellent when using a turbocharger 20 or a compressor for pressure charging the intake air.

Further, the exhaust valve 1 may be applied to a two-stroke internal combustion engine which is not operated with diesel fuel but with gas, gasoline or other fuel.

At a suitable position in the outlet chamber 105, 205, 305 or in the exhaust gas removal passage 106, 206, 306, a pressure sensor may be provided which controls the respective valves 130, 230, 330 so that the pressure of the exhaust gas partial stream is maintained at an optimally high value can. For this purpose, at least a variable control of the valve 130, 230, 330 is advantageous, which is then actuated on the basis of the pressure measured by the sensor.

In the exemplary embodiments, the exhaust valve 1 is shown mounted on the cylinder head of the internal combustion engine. In this case, a single outlet valve 1 is shown on the internal combustion engine for the combustion chamber 3. However, a plurality of exhaust valves may be provided for each combustion chamber having the construction of the above-described embodiments. There is also the option of only one of several exhaust valves, the are provided for a combustion chamber to equip with the construction according to the embodiments. The further exhaust valves may then have an ordinary construction without the exhaust gas extraction device.

While in the embodiments, the operation of the exhaust valve 1 in particular Fig. 5 is shown via a camshaft 208e, the operation of the exhaust valve 1 can be done in any way. In particular, an electromagnetic, hydraulic, pneumatic or other type of operation is possible. Also, especially in Fig. 5 the kinematic links between the throttle valve 215 and the exhaust gas removal valve 230 shown via a mechanical coupling. This mechanical coupling can be replaced by actuators actuated by the central control of the engine control system. The actuators may be electromagnetic, hydraulic, pneumatic or other type elements.

Although the entrance area in the embodiments is shown coaxially disposed about the valve stem of the exhaust valve, the entrance area may also be located adjacent the valve stem. Decisive here are the actual flow conditions behind the opening exhaust valve. It is conceivable, for example, that a strongly curved channel is arranged around the valve stem, so that the flow velocity of the exhaust gas radially at a distance from the valve stem shows peaks or has high averaged values. Essential to the invention is the arrangement of the entrance area in the area with particularly high flow rates independent of the arrangement with respect to the other elements of the outlet valve.

Claims (33)

Device for removing an exhaust gas partial flow from an exhaust gas line (105; 205; 305) of an internal combustion engine with a partial exhaust gas line (106; 206; 306) opening into the exhaust gas line (105; 205; 305), the input region (120; 220; is arranged opposite to the exhaust gas flow, so that the partial exhaust gas flow can enter into the inlet region (120; 220; 320) of the partial exhaust gas line (106; 206; 306) by utilizing the dynamic pressure of the exhaust gas flow. Device according to Claim 1, characterized in that the input region (120; 220; 320) is arranged in a partial cross-section region of the exhaust gas line (105; 205; 305), in which at least in a predetermined operating region of the internal combustion engine a flow velocity of the exhaust gas flow averaged over the partial cross section is higher than averaged over the total cross-section flow velocity of the total exhaust gas flow. Apparatus according to claim 1 or 2, characterized in that the inlet region (120; 220; 320) of the partial exhaust gas line in the flow direction immediately after a flow control member (101, 104; 201, 204; 201, 304) is arranged. Device according to claim 3, characterized in that the input region (120; 220; 320) is arranged in a region of the exhaust gas line (105; 205; 305) in which Flow velocity peaks occur in the course of an opening operation of the flow control element (101, 104, 201, 204, 201, 304) at least in a predetermined operating region of the internal combustion engine relative to the overall cross section of the exhaust gas line (105; 205; 305). Device according to one of claims 1-4, characterized in that the pressure in the partial exhaust gas line (106; 206; 306) is higher than the pressure in the exhaust gas line (105; 205; 305) when the partial exhaust gas flow is withdrawn at least in a predetermined operating region of the internal combustion engine. without removal of the partial exhaust stream. Device according to one of claims 3-5, characterized in that the flow control member (101, 104; 201, 204; 201, 304) is an exhaust valve (1) of the internal combustion engine. Device according to one of claims 3-6, characterized in that the flow control member (101, 104; 201, 204; 201, 304) as a poppet valve with a valve plate (101; 201; 301) and a valve stem (102; 202; 302) wherein the valve stem (102; 202; 302) is encompassed by the inlet region (120; 220; 320) of the partial exhaust gas line (106; 206; 306). Device according to one of Claims 1-7, characterized in that the partial exhaust gas line (106; 206; 306) and / or the inlet region (120; 220; 320) of the partial exhaust gas line (106; 206; 306) are coaxial with the exhaust gas line (105; 205, 305) is arranged. Device according to one of claims 1-8, characterized in that an inner contour of the Partial exhaust gas line (106; 206; 306) in the input area (120; 220; 320) forms a diffuser. Device according to one of claims 1-9, characterized in that the partial exhaust gas line (106; 206; 306) in the input region (120; 220; 320) is designed as a pitot tube. Device according to one of claims 1-10, characterized in that the partial exhaust gas line (106; 206; 306) is provided with a flow control device (130; 230; 330) with which the flow in the partial exhaust gas line (106; 206; 306) is controlled becomes. Device according to claim 11, characterized in that the flow in the partial exhaust gas line (106; 206; 306) is controlled by the flow control device (130; 230; 330) in dependence on the flow characteristic in the exhaust gas line (105; 205; 305) and / or the operating condition of the internal combustion engine is controlled. Apparatus according to claim 11 or 12, characterized in that the flow control means (130; 230; 330) is a valve provided in the partial exhaust gas line (106; 206; 306) which is actuated to control the flow between the partial exhaust gas line (106; 206; 306) and the exhaust pipe (105; 205; 305). Apparatus according to any one of claims 11-13, characterized in that the flow control means (230) is a poppet valve operable by a cam mechanism (208). Device according to one of claims 11-13 , characterized in that the flow control device (130) is a rotary valve disposed on the valve stem (102) of the exhaust valve (1). Apparatus according to claim 15, characterized in that the rotary valve (130) has a fixed ring element (109) and a rotatable annular element (110) arranged coaxially therewith, having corresponding openings, wherein by rotating the rotatable ring element (110) relative to the fixed one Ring element (109) is allowed or prevented flow through the openings. An apparatus according to claim 16 , characterized in that the fixed ring member (109) is attached to the input portion (120) of the partial exhaust gas line and the rotatable ring member (110) is attached to the valve stem (102) so that the rotatable ring member (110) is twisted the valve stem (102) is rotatable relative to the fixed ring member (109). Device according to one of claims 11-13, characterized in that the flow control device (330) comprises a valve seat (309) provided at the inlet region (320) of the partial exhaust gas line (306) and coaxial with the valve stem (302) of the flow control element (301, 304). displaceable valve body (308) is constructed, wherein the valve body (308) can be brought into abutment against the valve seat (309) and lifted from this, to close the input region (320) of the partial exhaust gas line (306) or open. Apparatus according to claim 18, characterized in that the valve body (308) in the flow direction of the partial exhaust gas flow is located behind the input region (320) of the partial exhaust gas line (306). Device according to one of claims 11-19, characterized in that the flow control device (130; 230; 330) is actuatable by an exhaust valve drive (208e) of the internal combustion engine. Device according to one of claims 11-20, characterized in that the flow control means (130; 230; 330) is operable in synchronism with the operation of the exhaust valve (1). Device according to one of claims 1-21, characterized in that in the exhaust pipe (7) is provided by a throttle valve actuator adjustable throttle valve (215), with which a back pressure in the exhaust pipe (7) is adjustable. Apparatus according to claim 22, characterized in that the throttle valve actuator is designed as a cam mechanism. Apparatus according to claim 22 or 23, characterized in that the throttle valve actuator and an actuator provided for the flow control means (130; 230; 330) are kinematically coupled together. Device according to one of claims 11-24, characterized in that the flow control device (130; 230; 330) is kept closed in predetermined operating states of the internal combustion engine, in particular when a minimum speed of the internal combustion engine is undershot. Device according to one of claims 1-25, characterized in that in the partial exhaust gas line (106; 206; 306; 12,13,14,16) there is provided a check valve (15) which causes a backflow to the inlet area (120; 220; 320 ) prevents the partial exhaust gas line. Internal combustion engine with a device according to one of claims 1 to 26, whose partial exhaust gas line (106; 206; 306; 12, 13, 14, 16) constitutes an exhaust gas recirculation line connected directly or indirectly to at least one combustion chamber (3) of the internal combustion engine. Internal combustion engine according to claim 27, characterized in that the internal combustion engine is a two-stroke diesel internal combustion engine, in particular with scavenging air blower and / or by a turbocharger (20) performed charging. Internal combustion engine according to claim 27, characterized in that the internal combustion engine is a four-stroke internal combustion engine, in particular with a turbocharger (20) performed charge. Internal combustion engine with an apparatus according to one of claims 1-26, wherein the partial exhaust gas line (106; 206; 306; 12,13,14,16) is connected to a turbine (21; 21a) of a turbocharger (20) and / or a turbine (51 ) is connected to an auxiliary device (50; 55), so that the turbocharger (20) and / or the auxiliary device (50; 55) are operated at least partially with the partial exhaust gas flow. An internal combustion engine according to claim 30, wherein said auxiliary means (55) is adapted to selectively supply the power of the internal combustion engine generated by said turbine (51). Internal combustion engine according to claim 31, wherein the turbine (51) can supply the power via a transmission of the crankshaft of the internal combustion engine. An internal combustion engine having an apparatus according to any one of claims 1-26, further comprising a pressure actuated actuator (60) operable with the apparatus for extracting a partial exhaust gas flow.

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