Crankcase lower part

A crankcase lower part for a supercharged internal combustion engine, wherein the crankcase lower part extends about a space below the crankshaft. The crankshaft lower part comprises an intercooler, which is cooled by coolant, and/or a charge air intermediate cooler, which is cooled by a coolant. The intercooler and/or the charge air intermediate cooler is integrated into the crankcase lower part.

BACKGROUND OF THE INVENTION

The object of the present invention is a crankcase lower part for a supercharged internal combustion engine having a liquid cooled intercooler and/or charge air intermediate cooler, the crankcase lower part enclosing the space below the crankshaft.

Internal combustion engines of the above-mentioned type typically have a cylinder head, a crankcase upper part and a crankcase lower part as the main components. The gas exchange valves, the injection nozzles, and the particular actuating devices are located in the cylinder head, which terminates the combustion chambers of the internal combustion engine on top. The cylinders having the pistons positioned therein and the crankshaft connected via connecting rods to the pistons are positioned in the crankcase upper part The crankcase lower part adjoining the crankcase upper part encloses the space below the crankshaft and comprises at least one oil sump used as a collection chamber for the engine oil. For reasons of stability, the crankcase lower part may be implemented in two parts in such a way that a yoke plate or a bearing plate is provided between crankcase upper part and oil sump. While the yoke plate is only used for reinforcing the crankcase upper part, the bearing covers for the crankshaft bearings are also molded onto the bearing plate, which is also referred to as a “bed plate”. An arrangement having a yoke plate is known, for example, from EP 0 663 522 Al, while EP 0 076 474 Al describes an arrangement having a bearing plate.

The terms cited above and in the related art: (crankcase) upper part and (crankcase) lower part, as well as statements such as “below the crank-shaft” etc. are not to be understood in a geodetic way in this context, but rather relate to the movement direction of the piston to the upper and/or lower dead center. Therefore, downward is in the direction in which the piston moves toward the lower dead center. This difference is important because the object of the present invention is applicable for internal combustion engines installed at any arbitrary angle of inclination.

As already noted, internal combustion engines of the type described above, particularly diesel internal combustion engines, are equipped with an arrangement for compressing the charge air; in this context one also refers to supercharging of the internal combustion engine. In this case, the supercharging may be single-stage or also multistage, particularly dual-stage. An internal combustion engine having dual-stage supercharging is known, for example, from DE 19961610. To reduce the charge air temperature, the arrangement described therein has an intercooler positioned after the first compressor stage as an intermediate cooler, whose object is to reduce the temperature level of the charge air already after the low-pressure stage, in order to thus increase the efficiency of the internal combustion engine and reduce the exhaust gas emissions. A further intercooler is typically positioned after the high-pressure compressor. It remains open how the intercoolers according to DE 19961610 are implemented.

In internal combustion engines of the type cited at the beginning positioned in vehicles, in addition to the problem of the required efficient cooling of the charge air, the problem exists that the amount of space available for installation is extremely small. Furthermore, for optimum throughput of charge air, it is required that the charge air be opposed with the smallest possible fluidic resistance.

It is therefore an object of the present invention to provide an intercooler which ensures efficient cooling of the charge air, takes the tight spatial conditions, particularly between low-pressure and high-pressure compressors, into consideration, and opposes the charge air with the smallest possible flow resistance.

SUMMARY OF THE INVENTION

This object is achieved by a crankcase lower part that comprises an intercooler, which is cooled by a coolant and/or a charged air intermediate cooler, which is cooled by a coolant, wherein the intercooler and/or intermediate cooler is integrated into the crankcase lower part.

The integration according to the present invention of the intercooler and/or the charge air intermediate cooler into the crankcase lower part advantageously uses an installation space present in internal combustion engines of the type described which has been largely unexploited until now and thus minimizes the space required for the intercooler and/or the charge air intermediate cooler. It suggests itself in this case to combine the construction of the intercooler and/or the charge air intermediate cooler with that of the crankcase lower part as well; this may advantageously be performed by attaching the intercooler and/or the charge air intermediate cooler to the oil sump or, if it is provided, to a yoke plate or a bearing plate. In particular, it is advantageous to implement the intercooler and/or the charge air intermediate cooler at least partially in one piece with the oil sump, the yoke plate, or the bearing plate.

The intercooler and/or the charge air intermediate cooler is advantageously subdivided into a first chamber guiding the coolant liquid and a second chamber guiding the charge air and sealed in relation to the first chamber, the first chamber being incorporated into a coolant liquid loop via a coolant liquid intake and a coolant liquid outlet, and the second chamber being connected via a charge air supply line to the pressure side of a compressor providing the charge air and via a charge air discharge line to a charge air header pipe or the intake side of a further compressor. The heat exchange area of the wall separating the first chamber from the second chamber is advantageously as large as possible in this case.

Furthermore, it is advantageous to implement the inter-cooler and/or the charge air intermediate cooler as tubular in order to minimize the flow resistance opposing the charge air as much as possible. In this case, the arrangement may advantageously be subdivided into an external pipe and a preferably tubular insert,; external pipe and insert may be used either as a coolant guide or as a charge air guide in this case. The external pipes may advantageously be attached to the oil sump, the yoke plate, or the bearing plate or may be implemented in one piece therewith.

In connection with the integration of the intercooler(s) into the crankcase lower part, in internal combustion engines having exhaust gas recirculation (EGR) and cooling of the recirculated exhaust gas, it suggests itself that the EGR cooler also advantageously be integrated into the crankcase lower part.

To guide the charge air from a first side of the internal combustion engine to a second different side, it is also possible to integrate one or more charge air lines without a cooling function into the crankcase lower part in order to thus avoid guiding charge air lines around the engine block. This is especially advantageous because the crank-case lower part does not have many functional parts which would obstruct guiding through of the charge air pipes.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The internal combustion engine1shown in a schematic illustration inFIG. 1has an exhaust gas header pipe5connected via exhaust manifold2to the combustion chambers3of the engine block4; the header pipe5guides the combustion gases over the turbine wheel6′ of the high-pressure compressor stage6and the turbine wheel7′ of the low-pressure compressor stage7and, via these, drives the compressor6″ of the high-pressure compressor stage6and the compressor7″ of the low-pressure compressor stage7. The charge air is suctioned by the compressor7″ of the low-pressure compressor stage7via an air filter (not shown), compressed, and then reaches the compressor6″ of the high-pressure compressor stage6via an intermediate cooler8. The second compression of the charge air occurs there, which then reaches the intake pipe10of the internal combustion engine1via a further intercooler9and/or reaches the combustion chambers3of the engine block4via the intake header11.

The object of the intermediate cooler8and the intercooler9is to cool the charge air heated by the compressor procedure as effectively as possible to optimize the efficiency, without negatively influencing the air throughput

Furthermore, an exhaust gas recirculation line13is provided, which connects the exhaust gas header pipe5to the intake pipe10via an EGR cooler12for cooling the recirculated exhaust gas and a control valve14for regulating the quantity of recirculated exhaust gas. The EGR cooler12is to prevent the charge air from being heated by the recirculated exhaust gas.

In the following, it is shown on the basis of several examples how the charge air intermediate cooler and/or the intercooler and/or the EGR cooler may be integrated into the crankcase lower part. These are merely schematic illustrations to illustrate the essential aspects of the present invention.

Firstly, an arrangement is shown inFIGS. 2 and 3, in which a charge air intermediate cooler and an intercooler are integrated into the oil sump forming the crankcase lower part. Identical components are provided with identical reference numbers in both figures.

FIG. 2shows a perspective illustration andFIG. 3shows a top view of an oil sump20forming the crankcase lower part, in which a charge air intermediate cooler21and an intercooler22are integrated. The charge air intermediate cooler21essentially comprises a charge air supply connecting part23positioned on a first long side of the oil sump20, from which two charge air pipes24′, which guide the charge air, traverse the oil sump to its second long side. A charge air collection chamber25is positioned on the second long side, which combines the charge air pipes24′ into one draft and connects them to charge air pipes24, which traverse the oil sump20in the direction toward its first long side originating from the second long side, where they open into a charge air discharge connecting part26.

First cooling inserts—not visible in FIG.2—are located in the interior of the charge air pipes24, which connect a coolant inflow chamber27, positioned on the first side of the oil sump20at the charge air discharge connecting part26, to a coolant collection chamber28on the diametrically opposite second side of the oil sump. Second cooling inserts—also not visible in FIG.2—lead, in the interior of the charge air pipes24′, from this coolant collection chamber28back to a coolant outflow chamber29positioned on the first side of the oil sump20at the charge air supply connecting part23.

Through the arrangement described above, the charge air compressed by a low-pressure compressor (7″FIG. 1) flows via a charge air supply line30into the charge air supply connecting part23and via this and the charge air pipes24′ into the charge air collection chamber25. From there, the charge air reaches a high-pressure compressor (6″FIG. 1) through the charge air pipes24, the charge air discharge connecting part26, and a charge air discharge line31. The charge air is cooled in the counterflow principle in that coolant from a cooling system (not shown) flows via the coolant inflow chamber27, the first cooling inserts, the coolant collection chamber28, and the second coolant inserts to the coolant outflow chamber29and from there returns back into the cooling system.

The charge air pipes24,24′ described above and also the charge air supply connecting part23, the charge air collection chamber25, and the charge air discharge connecting part26may be produced in one piece with the oil sump using casting, but it is also conceivable that the arrangement is completely or partially constructed from individual parts.

The intercooler22shown inFIGS. 2 and 3is used, as already described in connection withFIG. 1, for the purpose of cooling charge air compressed again by the high-pressure compressor (6″FIG. 1) and heated at the same time. The intercooler22is positioned below the oil sump20in its flat part, attached thereto in such a way that it leads from the first long side of the oil sump20under it through to the second side of the oil sump20. The charge air provided by the high-pressure compressor (6″FIG. 1) is supplied on the first long side of the oil sump20to the intercooler22via a charge air connection32and through this reaches the second long side of the oil sump20, where a charge air discharge33is positioned at the intercooler22, from which the charge air reaches the intake pipe (10FIG. 1) via a connecting pipe. A heat exchanger (not visible), which coolant flows through, is positioned in the intercooler22, which is connected via a coolant inlet34and a coolant outlet35to a cooling system (not shown).

The arrangement described above in connection withFIGS. 2 and 3may, of course, be altered so that the intermediate cooler21may also assume the function of an intercooler, particularly with single stage supercharging, but the intercooler22may also assume the function of a charge air intermediate cooler.

To illustrate the internal construction of the charge air intermediate cooler21described above in connection withFIGS. 2 and 3, sections are taken through the illustration inFIG. 3along lines A-A′ and B-B′.FIG. 4shows a sectional illustration along the line A-A′ through the charge air pipe24. The wall36of the charge air pipe encloses a cooling insert comprising four pipes37, which coolant flows through. The space between the pipes37and the wall36has the charge air flowing through it, so that the largest possible surface results between the area the coolant flows through and the area the charge air flows through and, in addition, the charge air is not opposed by any unnecessary flow obstruction. The charge air pipe24is contoured in the areas38in this case in such a way that the crankshaft (not shown) may dip into these areas38as it revolves, as a result of which the overall height of the arrangement is minimized.

FIG. 5shows, in a longitudinal section along line B-B′, the charge air pipe24, which is implemented in one piece with the oil sump20, the charge air discharge connecting part26and the charge air collection chamber25. The coolant inflow chamber27is positioned at the charge air discharge connecting part26, while the coolant collection chamber28is positioned at the charge air collection chamber25. The charge air pipe24, the charge air discharge connecting part26, and the charge air collection chamber25are penetrated by the pipes37in the longitudinal direction, the pipes37being held via holding plates39,39′. The holding plates39,39′ simultaneously form the closure cap for the charge air supply connecting part26to the coolant inflow chamber27and for the charge air collection chamber25to the coolant collection chamber28. Two areas delimited in relation to one another result through the construction described above, the area which the charge air flows through, comprising charge air collection chamber25, charge air pipe24, and charge air discharge connecting part26and, in addition, the area the coolant flows through, which comprises the coolant inflow chamber27, the pipes37, and the coolant collection chamber28.

For better heat absorption by the pipes37through which the coolant flows, these pipes may be implemented as profiled as shown inFIG. 6in a sectional illustration along line C-C′, in order to make the surface of the wall of the pipes37in contact with the charge air as large as possible and thus favor the heat transfer.

A charge air intermediate cooler of the type described inFIG. 2may also, as already noted above, be integrated in a yoke plate.FIG. 7shows an arrangement of this type in a perspective illustration. The construction of the charge air intermediate cooler is identical to that described in connection withFIG. 2, so that the corresponding reference numbers are taken fromFIG. 2and reference is made to the description ofFIG. 2in regard to construction and mode of operation, only the deviations from the example according toFIG. 2being explained in greater detail in the following. The arrangement illustrated inFIG. 7shows a yoke plate40which is implemented as a ladder frame, the charge air pipes24,24′ implemented in one piece with the yoke plate40, which provide a connection from a first long side of the yoke plate40to its second long side, assuming the function of the crosspieces which stiffen the ladder frame. Analogously to the illustration inFIG. 2, the charge air supply connecting part23having charge air supply line30and coolant outflow chamber29positioned thereon as well as the charge air discharge connecting part26having charge air discharge line31and coolant inflow chamber27positioned thereon are located on the first long side of the yoke plate40. Also analogously to the example according toFIG. 2, the charge air collection chamber25and the adjoining coolant collection chamber28are positioned on the second long side of the yoke plate40to produce the connection between the charge air pipes24,24′. The cooling inserts are located in the charge air pipes24,24′, as described in connection withFIGS. 2 through 5. The charge air guiding and the guiding of the coolant corresponds to the example described according toFIG. 2, so that reference is made to the corresponding parts of the description in this regard.

An oil sump41(shown with dashed lines), which forms the crankcase lower part together with the yoke plate40, adjoins the yoke plate40on the bottom to receive the lubricant required for the engine lubrication.

Furthermore, in the example according toFIG. 7, an intercooler80positioned laterally to the oil sump41on the second long side of the yoke plate40is provided. To connect the intercooler80to the high-pressure compressor (6″FIG. 1) placed on the first side of the yoke plate40, a further charge air pipe81is integrated into the yoke plate40leading from its first long side to its second long side. The charge air flows from the high-pressure compressor via a connection line82to the further charge air pipe81, and an attachment pipe83to the intercooler80and therefrom via a pipe line84to the intake pipe (10FIG. 1). The intercooler is incorporated into a coolant loop (not shown) via coolant connections85,85″.

A further alteration of the arrangement according to the present invention is shown inFIGS. 8 and 9. The plate illustrated there, which is implemented in the form of a ladder frame, is embodied as a bearing plate. Bearing plates or also bed plates of this type form, as already noted at the beginning, a module which assembles the bearing covers for the crankshaft bearings into one component in such a way that these may be mounted in one work step.FIG. 8shows the arrangement in a top view,FIG. 9shows the side view in the viewing direction corresponding to the arrow identified by “D” (FIG. 8).

The bearing plate42comprises a peripheral frame43, which has transverse struts, which are formed by charge air pipes44,44′ and, in addition, by bearing cover carriers45. Bearing covers46are positioned on the peripheral frame43, the bearing cover carriers45, and the charge air pipes44, preferably implemented in one piece therewith, which extend out of the plane formed by the peripheral frame43in the direction toward the crankshaft47(shown by dashed lines inFIG. 9). The bearing covers46each form one half of the crankshaft bearings, the respective other halves are positioned on the crankshaft upper part (not shown).

In this example as well, a charge air intermediate cooler21is used, which corresponds in its essential constructive features to the charge air intermediate cooler described in the example according toFIG. 2, so that the reference numbers fromFIG. 2are also taken in the example shown inFIGS. 8 and 9in regard to the charge air intermediate cooler where there is constructive correspondence and reference is made to the corresponding description parts of this example in regard to the implementation and function. The charge air pipes44,44′ deviate from the embodiment according toFIG. 2and/orFIGS. 4 and 5in that the bearing covers46are positioned on the charge air pipes44,44′ and screw holes48for attaching the bearing covers46to the bearing block (not shown) are provided therein.

FIG. 10shows an example of the construction of the charge air pipes44,44′. In this sectional illustration along line E-E′ (FIG. 8), the charge air pipe44′ is shown in section transversely to its longitudinal extension. A bearing cover46is implemented in one piece with the charge air pipe44′ and divides the inner chamber of the charge air pipe44′ into two drafts49,49′, each of which is penetrated by a coolant pipe50,50′. The drafts49,49′ have the charge air flow through them, while the coolant pipes50,50′ have coolant flowing through them, preferably in counterflow to the charge air.

To receive the lubricant required for the engine lubrication, an oil sump51adjoins the bearing plate42on the bottom, which forms the crankcase lower part together with the bearing plate42. An intercooler52may be positioned on the oil sump51, as shown by dashed lines in FIGS.8and9.

FIG. 11shows a perspective illustration of a possibility for integrating a charge air intermediate cooler, an inter-cooler, and an EGR cooler in the crankcase lower part. An intercooler66, a charge air intermediate cooler55, and an EGR cooler56are positioned on a yoke plate53, which also forms an oil collection chamber54. The charge air intermediate cooler55essentially comprises a charge air supply connecting part57positioned on a first long side of the yoke plate53, from which a charge air pipe58guiding the charge air leads to the second long side of the yoke plate53. A charge air overflow chamber59is positioned on the second long side, which connects the charge air pipe58to a charge air pipe58′, which returns to the first long side of the yoke plate53starting from its second long side, where it discharges into a charge air discharge connecting part60.

A first cooling insert—not visible in FIG.11—is located in the interior of the charge air pipe58′, which connects a coolant inflow chamber61positioned on the first side of the yoke plate at the charge air discharge connecting part60to a coolant overflow chamber62on the diametrically opposite second long side of the yoke plate53. From this coolant overflow chamber62, a second cooling insert—also not visible in FIG.2—leads in the interior of the charge air pipe58back to a coolant outflow chamber63positioned on the first side of the yoke plate at the charge air supply connecting part57.

Through the arrangement described above, the charge air compressed by the low-pressure compressor (7″FIG. 1) flows via a charge air supply line64into the charge air supply connecting part57and, via this and the charge air pipe58, into the charge air overflow chamber59. From there, the charge air reaches the high-pressure compressor (6″FIG. 1) through the charge air pipe58′, the charge air discharge connecting part60, and a charge air discharge line85. The charge air is cooled in the counterflow principle in that coolant from a cooling system (not shown) flows via the coolant inflow chamber61to the first cooling insert and to the coolant overflow chamber62and the second cooling insert to the coolant outflow chamber63and from there returns into the cooling system.

The intercooler66shown inFIG. 11is used, as already described in connection withFIG. 1, for cooling the charge air compressed again by the high-pressure compressor (6″FIG. 1) and heated at the same time. The intercooler66is positioned below the oil collection chamber54on the yoke plate53in such a way that it leads from the first long side of the yoke plate53under it through to the second long side of the yoke plate53. The charge air provided by the high-pressure compressor (6″FIG. 1) is supplied on the first long side of the yoke plate to the intercooler66via a charge air connection (not visible) and, through this, reaches the second long side of the oil sump, where a charge air discharge68is positioned on the intercooler66, from which the charge air reaches the intake pipe (10FIG. 1) via a connection part (not shown). A heat exchanger through which coolant flows is positioned in the intercooler66, which is connected via a coolant supply (not visible) and a coolant drain70to a cooling system (not shown).

In addition to the charge air intermediate cooler55and the intercooler66, an EGR cooler56is positioned on the yoke plate53, whose object is to cool the exhaust gas re-circulated by the exhaust gas header pipe (5FIG. 1) to the intake pipe (10FIG. 1) enough that the exhaust does not noticeably influence the charge air temperature in the intake pipe (10FIG. 1). The EGR cooler56comprises an EGR supply connecting part71positioned on the first long side of the yoke plate53, from which two exhaust pipes72, which guide the exhaust gas to be recirculated, lead to the second long side of the of plate53, where they open into an EGR exhaust connecting part73.

Cooling inserts—not visible in FIG.11—constructed analogously to the illustrations inFIGS. 4 and 5are located in the interior of the exhaust pipes72, which connect an outflow chamber74positioned on the first side of the yoke plate73at the EGR supply connecting part71to an inflow chamber75positioned on the diametrically opposite second long side of the yoke plate53at the EGR exhaust connecting part73.

Through the arrangement described above, exhaust gas to be recirculated by the exhaust gas header pipe (5FIG. 1) flows via an EGR supply line76into the EGR supply connecting part71and via this and the exhaust pipes72into the EGR exhaust connecting part73and an EGR return line77to the intake pipe (10FIG. 1). The recirculated exhaust gas is cooled in the counterflow principle in that coolant from a cooling system (not shown) flows via the inflow chamber75and the cooling inserts (not visible) to the outflow chamber74and from there returns into the cooling system.

The arrangement described above is terminated on the bottom by an oil collection sump78and forms the crankcase lower part together with it.

Proceeding from the examples described above, numerous alterations may be conceived, which may be derived without difficulty from the above description and knowledge typical for one skilled in the art without leaving the basic inventive idea, these embodiments thus only having exemplary character. In particular, manifold alterations suggest themselves for the cooling principle. Thus, in particular, the cooling principle of the charge air guided in an external pipe and/or the recirculated exhaust gas through a cooling insert positioned in the external pipe may be reversed in such a way that the charge air and/or the exhaust gas to be recirculated is guided in an internal pipe and cooled by mantle cooling between an external pipe and the internal pipe. Furthermore, the counterflow principle selected for the above examples is only one of many possibilities; parallel flow, transverse flow, reverse flow, or mixed variations may also be used, of course. How the arrangement is implemented in practice is a question of the quantity of heat to be transferred and thus the layout of the arrangement. This layout is in turn familiar for one skilled in the art.

To improve the cooling effect of the arrangement further, the possibility exists of providing the partition walls between the coolant and the charge air, and/or the exhaust gas to be recirculated, with a macrostructure in order to enlarge the area available for cooling. A macrostructure is understood in this case as multiple protrusions and/or depressions which are distributed over the partition walls uniformly or randomly.

The arrangement may also be altered so that the pipes which the charge air flow through are divided into multiple parallel chambers. There is also the possibility of providing multiple drafts for the areas which coolant flows through. The arrangement according to the present invention may be produced especially favorably through casting from aluminum or cast iron.

The fact that only in-line engines are used in the examples to explain the present invention does not indicate any type of restriction; the arrangement according to the present invention is also obviously suitable for internal combustion engines having banks of cylinders arranged in V-shapes.

The specification incorporates by reference the disclosure of Austrian priority document AT 685/2005 filed Apr. 25, 2005.