DE102008029904A1 - Device and method for crankcase ventilation - Google Patents

Abstract

The invention relates to a device and a method for ventilating a crankcase (10) of a supercharged internal combustion engine, wherein a plurality of collecting chambers (28, 30) for ventilation gases are provided, having individual oil separators (88, 90) associated therewith. Contrary to full load operation, during partial load operation the ventilation gas of a collecting chamber (28) is fed to a non-associated oil separator (90) and is ventilated using the same.

Description

The The invention relates to an apparatus and a method for crankcase ventilation and returning the vent gases in the combustion chamber of a supercharged internal combustion engine.

At the Operation of internal combustion engines, in particular reciprocating engines, can combustion gases between the cylinders and the Escape the piston rings in the crankcase. These gases are referred to as blow-by gases and can be used within the crankcase considerable pressures Build so that a vent of the crankcase is required. The blow-by gases in the crankcase are filled with engine oil burdened, which is why they may not be released into the environment and usually go through an oil separator to finally to be routed into the intake tract of the internal combustion engine. From Here the gases are returned to the combustion chambers of the cylinders directed.

Around the pressure in the crankcase on a possible can regulate constant value, pressure regulators or also variable throttles with or without check-back function, z. B. so-called. PCV valves (positive crankcase ventilation) provided be. About such control valves, the negative pressure in Intake tract used to suck gases from the crankcase. If a turbocharger is provided, in part-load operation extracted gas downstream of the turbocharger in the intake sucked, and at full load upstream of the turbocharger in the intake tract. Check valves must be at full load Prevent the pressure on the so-called. Part-load ventilation is transferred to the crankcase.

The Extraction of the gases takes place either in the region of the bottom of the crankcase above the oil level or in the area of the cylinder head. at A suction in the area of the cylinder head is distinguished in particular between the arrangement of the collection chamber in the cylinder head itself or in a valve hood surrounding the cylinder head. The Collection chambers are otherwise the rooms in which the vent gas is in front of the exhaust.

From the EP 1 310 639 A1 is a crankcase ventilation in a V-engine known. Each cylinder bank is associated with a turbocharger, with a common intake manifold is provided for both rows. In addition, there is a common oil separator for both rows of cylinders, wherein the provided in the cylinder head cover collecting chambers are coupled together via a connecting line. The gas is then introduced in partial load operation downstream of the throttle cap in the intake and at full load in an air supply pipe upstream of the turbocharger.

A another variant of a crankcase ventilation A V-engine sees its own for each cylinder row Turbocharger and a separate oil separator. For oil separators, In particular, inertial, is the degree of separation partly dependent on throughput. There are therefore oil separators, in which individual stages (in multiple cyclone separation individual Cyclones) can be switched on via switching elements. Such switching elements usually consist of a spring and a, by the spring actuated closure element.

task The invention is to provide a simpler device for Crankcase ventilation and a method for this purpose specify.

The Inventive device for crankcase ventilation and recycling the vent gases (blow-by gases called) in the combustion chamber of a supercharged internal combustion engine has several the crankcase and single or multiple cylinders assigned collecting chambers for venting gases in front. These collection chambers can be in the crankcase or be provided on the cylinder head side. In a suction line, although several suction lines can be provided, At least one turbocharger is arranged. Furthermore each collection chamber is at least a separate oil separator assigned. A part throttle return line leads from an oil separator to the downstream of the turbocharger to the intake, in which it flows. About that In addition, each oil separator is a full return line provided for vent gas upstream of the turbocharger opens into the intake. In full load operation bleeds vent gas to each collection chamber the assigned, own oil separator in the suction line. At least in part-load operation, however, the collection chambers are fluid interconnected, and vent gas is at least two collecting chambers via the oil separator one Collecting chamber led into the suction line.

The Inventive device provides that in Part load operation are less oil separators in operation, so that then working oil separator a higher Throughput and Ölabscheidegrad achieve than in partial load operation. As a result, additional switching elements are unnecessary. Preferably, the device according to the invention thus no switchable oil separator.

According to the preferred embodiment, a plurality of rows of cylinders are provided, and each row of cylinders has its own collection chamber. As already explained, these collecting chambers may be sections of the crankcase or the cylinder be assigned to the heads and in their range.

As also already explained, the collection chambers be fluidly connected to each other. This can be preferred over the common crankcase done so that additional Lines could be omitted.

Preferably are also provided several turbochargers, each individual or associated with a group of cylinders. According to the preferred embodiment has each cylinder bank (also cylinder bank called) a dedicated turbocharger.

Prefers Each turbocharger is assigned an oil separator.

From the flowed through in partial load operation oil separator Partial return lines lead to the suction lines downstream of the multiple turbochargers. It should be emphasized that, of course also several oil separators can work in partial load operation, but not all. From these working oil separators will the gas then branched back to the intake pipes, too to intake pipes of non-active oil separators.

Vollastrückführleitungen may be provided by the oil separators lead to the intake pipes of several turbochargers. These full return lines are then in Full load operation the gas to the intake pipes upstream the turbocharger pass.

According to one Embodiment of the invention is one, preferably only a, ventilation duct provided, leading to a collection chamber leads and over the connection of the collecting chambers ventilated. Such a ventilation line allows a so-called. Rinsing the crankcase with fresh air, whereby u. a. reduces the chemical aging of the lubricating oil becomes. In this embodiment, the construction effort for the ventilation is very low.

Prefers can the aeration line in the oil separator, which does not work in partial load, open, so that of this is done from the ventilation. Also by this leaves the number of connections or the number of connections Reduce provided parts.

Around To reduce the number of lines, the aeration line the full return line of the partial load operation not working oil separator. This line has so to speak a double function and flows through in two directions, in one direction from the vent gas and in the other Direction from the fresh air.

Around switchable valves to avoid and yet a clear flow To reach in the various load operations are check valves arranged in the Vollastückführleitungen. These Prevent suction through these lines in partial load operation.

The Check valve in the as a ventilation line serving full return line can with a throttled bypass be provided over the then vented although the check valve is actually in the closed position is. This embodiment can be realize very cost-effective.

In the at least one or each partial load line should have a throttle unit be arranged with check function (eg PCV valve). When supplying fresh air, such PCV valves prevent backflow the gases. Such PCV valves are available in heatable and unheated Execution. About the PCV valves are using the negative pressure in the intake tract the exhaust gases sucked, namely in partial load operation.

The oil separators are inertial separators, in particular cyclone separators, As already mentioned, even non-switchable cyclone separators are preferred.

The Venting is carried out according to the preferred Embodiment cylinder head side, wherein the collecting chambers may be provided in the cylinder head or in valve covers.

at the embodiment with venting over the Crankcase itself can be the collection chambers course also merging sections be the interior of the crankcase. To an optimal Ventilation and ventilation, d. H. rinse, It would be beneficial in this context if the lines as far away from each other in the crankcase lead.

The Invention also relates, as already explained, a method for venting a crankcase an internal combustion engine, in particular a reciprocating piston engine, the multiple collection chambers for venting gases has its own oil separator assigned. The procedure provides that in the partial load mode, the vent gases a collection chamber to an unassigned oil separator guided and vented over this, whereas in full load operation the venting gases of the collecting chambers over their own, each associated oil separator vented become.

Further Features and advantages of the invention will become apparent from the following Description of a preferred embodiment, which is shown in FIG the single schematic figure is shown.

In the figure, an engine, more specifically a reciprocating engine of an internal combustion engine is shown. The engine is a V-type engine with a crankcase in this embodiment 10 , which two cylinder rows 12 . 14 having. With 16 are the pistons and with 18 the intake and exhaust valves referred to in the cylinder heads 20 . 22 are housed. Each cylinder bank is equipped with a so-called valve cover 24 . 26 covered, with the valve covers 24 . 26 can also merge into one another in one piece.

Between the valve covers 24 . 26 and the cylinder heads 20 . 22 are each so-called collection chambers 28 . 30 intended for venting gases.

These bleed gases are with water, oil from the crankcase 10 and other components contaminated blow-by gases 32 which is between the pistons 16 and the cylinders 34 . 36 from the appropriate work spaces in the crankcase space 38 can escape. In the crankcase room 38 tear these blow-by gases 32 oil 40 at the bottom of the crankcase space 38 With. The resulting vent gas 32 is then in the crankcase space 38 where it would create an overpressure.

The vent gases 32 do not just spread in the crankcase space 38 out, but can through passages 42 . 44 in the cylinders 34 . 36 or between the cylinders 34 . 36 and the valve covers 24 . 26 up to the cylinder heads 20 . 22 stream.

In the illustrated embodiment, for each cylinder bank 12 . 14 between the cylinder heads 22 . 24 and the associated valve covers 24 . 26 a separate collection chamber 28 . 30 intended for the vent gases.

Alternatively, the collection chambers 28 . 30 of course also in the area of cylinder heads 20 . 22 and the cylinder head cover be formed, as for example in the DE 35 09 439 C2 is shown.

The collection chambers 28 . 30 are over the crankcase 10 or, more precisely, about the merging passages 42 . 44 (eg on the mutually facing sides of the cylinders 34 . 36 ) connected with each other. The connection point is with 46 designated. In the area of this junction 46 is also one of the multiple outflow openings 48 provided for the vent gas. The arrow 50 symbolizes at this point also the vent gas, which in the passages 42 . 44 flows.

Of the Of course, shown engine block is in an air supply and an exhaust system integrated, which is described in more detail below becomes.

Each cylinder bank 12 . 14 is a separate, divided into several sections suction line 52 . 54 assigned, in each case a separate intake silencer 56 and a possibly necessary hot-film air mass meter 58 are integrated. Every intake pipe 52 . 54 is also its own turbocharger 60 . 62 assigned to an exhaust pipe 64 . 66 is integrated and driven by the exhaust gas.

The turbocharger 60 . 62 divide the intake pipes 52 . 54 in an upstream section 68 . 70 and a downstream section 72 . 74 ,

In the respective downstream section 72 . 74 are each a throttle 76 . 78 as well as a charge air cooler 80 . 82 integrated.

In the internal combustion engine is a device for crankcase ventilation and recycling the vent gases in the respective combustion chamber 84 . 86 the cylinder 34 respectively. 36 intended.

This device includes, among other things, the collection chambers 28 . 30 and at least one each collection chamber 28 . 30 assigned, own oil cutter 88 . 90 ,

Preferably, the oil separators 88 . 90 Cyclone separator, without switchable cyclones.

From the oil separator 88 leads a full return line 92 in the upstream section 68 the suction line 52 for the cylinder bank 12 , Into the full return line 92 is a check valve 94 integrated, which has a bypass with choke 96 can be bridged. Of course, the bypass can with throttle 96 also in the check valve 94 be fully integrated.

The oil separator 90 the other collection chamber 30 has one from the oil separator 90 Outgoing gas return line, which is divided several times, namely on the one hand in a full return line 98 that go into the upstream section 70 opens and in the a check valve 99 sits, as well as two part throttle return lines 100 . 102 ,

The part throttle return line 100 is with a so-called PCV valve 104 provided and opens into the downstream section 72 the oil separator 90 actually not assigned suction line 52 ,

The part throttle return line 102 is also with a PCV valve 106 provided and opens into the downstream section 74 the oil separator 90 associated intake pipe 54 ,

The partial strain return lines 100 . 102 preferably ends after the throttle 76 . 78 and also preferably after the intercoolers 80 . 82 ,

in the The following are the operation of the crankcase ventilation device and described in more detail the procedure below.

In full-load operation, the exhaust gases drive the two turbochargers 60 . 62 on, so that in the downstream sections 72 . 74 a relatively high pressure prevails. The ones in the combustion chambers 84 . 86 resulting exhaust gases are via the exhaust valves 18 to the exhaust pipes 64 . 66 guided. Blow-by gases 32 but arrive in the crankcase space 38 where they too oil 40 carried away. The resulting venting gases pass over the outflow openings 48 in the passages 42 . 44 and thus in the collection chambers 28 . 30 in the area of the cylinder heads 20 . 22 ,

In the upstream sections 68 . 70 There is a negative pressure, so that the venting gases through the oil separator 88 . 90 flow (see arrows in the collection chambers 28 . 30 ). In the oil separators 88 . 90 The retained oil is then in the collection chambers 28 . 30 attributed to where it is on the walls of the passages 42 . 44 along back to the crankcase room 38 flows (see thick arrows 108 ). The vent gas then flows from the oil separators 88 . 90 through the open check valves 94 . 99 in the upstream sections 68 . 70 back into the exhaust pipes 64 . 66 , At full load are the PCV valves 104 . 106 due to the high pressure in the downstream sections 72 . 74 closed.

At partial load is in the downstream sections 72 . 74 a vacuum exists, so that the PCV valves 104 . 106 open, whereas the valves 94 . 99 are closed.

Because the collection chamber 28 does not have its own, open discharge line in partial load operation, the vent gas flows into the collection chamber 28 over the flow connection (here the passages 42 . 44 ) to the collection chamber 30 , This results in a higher amount of vent gas through the oil separator 90 sucked, which can work more effectively.

This switchover between partial and full load takes place for the venting without additional valve devices. The vent gas then splits downstream of the oil separator 90 on and passes through the open PCV valves 104 . 106 in the downstream sections 72 . 74 the exhaust pipes 64 respectively. 66 ,

In partial load operation also takes place ventilation by fresh air, namely aeration of both the collection chambers 28 . 30 as well as the crankcase space 38 , About the throttle 46 Namely, fresh air is sucked in (by a broken line parallel to Vollastruckführführleitung 92 symbolized) via the full return line 92 in the oil separator 88 and thus in the collection room 28 , From there, the fresh air can flow through all provided with the vent gas chambers and chambers and the oil separator 90 reach.

The inventive method thus provides that in part-load operation, the venting gases of a collection chamber 28 to an unassigned oil separator 90 is guided and vented through this, whereas in full-load operation, the venting gases of the collecting chambers 28 . 30 via their own, respectively assigned oil separators 88 . 90 be vented.

In partial load operation, a higher separation efficiency in the oil separator 90 and thus achieves an efficiency improvement, since separators are normally designed for maximum throughput. The oil separator 90 So receives twice the amount of vent gas including aeration gas and works almost continuously only at maximum throughput. It also results in a lower coking of the intake valves. Since no additional switching elements are needed, resulting in lower costs and a lower weight.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1310639 A1 [0005]
• - DE 3509439 C2 [0032]

Claims (17)

Device for crankcase ventilation and return of the venting gases into the combustion chamber ( 84 . 86 ) of a supercharged internal combustion engine, with a plurality of the crankcase ( 10 ) and one or more cylinders ( 34 . 36 ) associated collecting chambers ( 28 . 30 ) for venting gases, at least one in a suction line ( 52 . 54 ) arranged turbocharger ( 60 . 62 ), several oil separators ( 88 . 90 ), each collecting chamber ( 28 . 30 ) at least one own oil separator ( 88 . 90 ), a partial load return line ( 100 . 102 ), by an oil separator ( 90 ) to the downstream of the turbocharger ( 60 . 62 ) to the intake line ( 52 . 54 ), with each oil separator ( 88 . 90 ) a full return line ( 92 . 98 ) upstream of the turbocharger ( 60 . 62 ) into the suction line ( 52 . 54 ), wherein at full load bleed gases each collecting chamber ( 28 . 30 ) via the assigned oil separators ( 88 . 90 ) into the suction line ( 52 . 54 ) and the collecting chambers ( 28 . 30 ) are fluidly connected at least in partial load operation and vent gas from at least two collecting chambers ( 28 . 30 ) via the oil separator ( 90 ) a collection chamber ( 30 ) into the suction line ( 52 . 54 ) flows. Device according to claim 1, characterized in that several rows of cylinders ( 12 . 14 ) are provided and each cylinder bank ( 12 . 14 ) own collection chamber ( 28 . 30 ) having. Apparatus according to claim 1 or 2, characterized in that the collecting chambers ( 28 . 30 ) via the common crankcase ( 10 ) are fluidly connected to each other. Device according to one of the preceding claims, characterized in that a plurality of turbochargers ( 60 . 62 ) are provided, the individual or a group of cylinders ( 34 . 36 ) assigned. Device according to claim 4, characterized in that each turbocharger ( 60 . 62 ) an oil separator ( 88 . 90 ) assigned. Apparatus according to claim 4 or 5, characterized in that of the flowed through in partial load operation oil separator ( 90 ) Partial load return lines ( 100 . 102 ) to the suction lines ( 52 . 54 ) downstream of the plurality of turbochargers ( 60 . 62 ) to lead. Device according to one of claims 4 to 6, characterized in that of the oil separators ( 88 . 90 ) Full load return lines ( 92 . 98 ) to the suction lines ( 52 . 54 ) of the associated turbocharger ( 60 . 62 ) to lead. Device according to one of the preceding claims, characterized in that a ventilation line is provided which leads to a collecting chamber ( 28 ) and via the connection of the collecting chambers ( 28 . 30 ) is vented. Apparatus according to claim 8, characterized in that the aeration line in the oil separators ( 88 ), which does not work in partial load operation, flows. Apparatus according to claim 8 or 9, characterized in that the ventilation duct, the Vollastückückführleitung ( 92 ). Device according to one of the preceding claims, characterized in that check valves ( 94 . 99 ) in the full return lines ( 92 . 98 ) are arranged. Apparatus according to claim 10 or 11, characterized in that the check valve ( 94 ) in the full line return line serving as a ventilation line ( 92 ) is provided with a throttled bypass. Device according to one of the preceding claims, characterized in that in the at least one or each partial load return line ( 100 . 102 ) a variable throttle, in particular a PCV valve ( 104 . 106 ), is provided. Device according to one of the preceding claims, characterized in that the oil separators ( 88 . 90 ) Inertial separators, in particular cyclone, are. Device according to one of the preceding claims, characterized in that the vent cylinder head side he follows. Apparatus according to claim 15, characterized in that the collecting chambers ( 28 . 30 ) in valve covers ( 24 . 26 ) are provided. Method for venting a crankcase ( 10 ) an internal combustion engine, the plurality of collection chambers ( 28 . 30 ) for venting gases to which own oil separators ( 88 . 90 ), characterized in that in part-load operation, the venting gases of a collecting chamber ( 28 ) to an unclassified oil separator ( 90 ) and vented through this, whereas in full-load operation, the venting gases of the collecting chambers ( 28 . 30 ) via their own assigned oil separators ( 88 . 90 ) are vented.