EP2977599A1 - Engine component of a reciprocating piston engine - Google Patents

Abstract

The invention relates to an engine component (1) of a reciprocating engine with a group of a plurality of juxtaposed cylinder (3), between each of which a web portion (2), wherein in the web region (2) between two adjacent cylinders (2) at least one, in particular transversely to A fluid channel (12; 22) is formed which connects a first and a second region (5a, 5b; 20, 20) of a fluid channel system so that a fluid from the first region (5a; 20 ) flows through the fluid channel (12; 22) into the second region (5b; 20) and thereby dissipates heat via the web region (2) out of the cylinders (3) and cools the web region (2). The invention further relates to an internal combustion engine with such an engine component and vehicle with an internal combustion engine.

Description

The invention relates to an engine component of a reciprocating engine. With a group of several juxtaposed cylinders, between each of which a web area runs.

In the present context, the term "engine component" includes in particular the cylinder crankcase, in which the actual cylinder or cylinder bores are formed, as well as the cylinder head, in which cylinder recesses corresponding to the cylinder bores formed in the cylinder crankcase are defined. These recesses should also be included in the present application by the term "cylinder". They define in the cylinder head the upper portion of the combustion chamber and accommodate openings for the valves and a receptacle for the spark plug or for an injection valve.

The terms "top" and "bottom" are used below so that "top" denotes the cylinder head area and "bottom" the crankshaft area. A group of juxtaposed cylinders refers to a series of at least two cylinders forming a row of cylinders.

In modern and very compact designed high-performance engines in particular the web areas between the cylinders are exposed to very high thermal loads. Here, the remaining web area is formed so thin that the cylinder partially comprehensive, provided for cooling the cylinder water pockets in the web area can not be formed. Additional, parallel to the cylinder axis and running between the water pockets coolant channels have limited effect in the web area. (cf., eg DE 10 2007 035 514 A1 )

In particular, in the upper region of the cylinder, the thermal stress is particularly high, since the actual combustion takes place here in reciprocating engines. With uncooled webs, the web temperatures in this upper region can increase so much that the so-called "web growth" occurs. This can cause the local thermal expansion in the upper land area to cause geometrical changes in the tube bore of the cylinder, negatively affecting performance and durability of the engine. Friction performance disadvantages and problems with sealing with the cylinder head gasket by lifting off can occur. This problem occurs in particular in the upper regions of the webs of the cylinder crankcase.

However, it can also occur in the web areas in the cylinder head, where an uneven temperature distribution can also lead to deformations that may have adverse effects on the valve seats or the sealing effect of the cylinder head gasket, for example.

Approaches in which the web area in the cylinder crankcase from the top of the cylinder head through obliquely abutting cooling water bores heat is to be withdrawn (see, eg EP 1 752 643 A1 ) require additional breakthroughs in the top deck, which reduce the effective sealing surface areas for the cylinder head gasket.

The object of the present invention is therefore to provide an engine component in which the abovementioned disadvantages are at least partially overcome.

This object is achieved by the engine component according to the invention according to claim 1, an internal combustion engine according to claim 11 and a vehicle according to claim 12.

The invention is characterized in that in the web region between two adjacent cylinders at least one, in particular transversely to a cylinder axis, extending fluid channel is formed, which connects a first and second region of a fluid channel system with each other, so that during operation of the internal combustion engine, a fluid from the first region flows through the fluid channel into the second region, thereby dissipating heat over the land area from the cylinder and cools the land area.

Such web cooling is particularly suitable for high performance engines to protect the web material and to limit the unwanted web growth. A designed as a fluid channel cooling channel effectively cools the critical area of the engine component (cylinder crankcase, cylinder head) and also requires no passages in the top deck between the cylinder crankcase and cylinder head. This simplifies the design of the cylinder head gasket, for the larger effective sealing surfaces are available.

In particular, in the "gusset areas" of adjacent cylinders in which the webs terminate, there remain important contiguous sealing surface areas which are known in the art cross-drilled watercooling, which run between the cylinder head and the cylinder crankcase, must be broken.

A transverse to the cylinder axis fluid channel also prevents further disadvantages of crossing holes or correspondingly formed during casting cooling channels. They run in the region of the reversal point of the piston rings, reduce in this critical area the web material under circumstances so far that the shape of the tube of the cylinder bore is changed here and can result in spite of the cooling friction losses. In addition, sharp edges or very narrow radii arise at the crossing points, which may be disadvantageous because of the possible concentrations of stress in terms of the strength of the engine component.

In this case, the fluid channel connects a first and second region of an oil channel system. Usually, the engine oil used primarily for lubrication and cooling of the bearing surfaces of the engine and has only a secondary cooling effect in the heat removal from the cylinder crankcase.

However, the use of the engine oil as a primary cooling medium or cooling fluid also has advantages over the cooling water provided with antifreeze and inhibitors. The evaporation and coking temperatures of conventional engine oil qualities are significantly higher than those of cooling water mixtures and closer to the temperatures typically occurring in the upper web area.

This also counteracts a risk that can occur in a water cooling in the high temperature range and in particular at narrow channel cross sections. Under certain circumstances, evaporation of the cooling water in such zones may cause film boiling. Stable vapor bubbles or layers or even stationary vapor pockets form, so that critical areas such as the land area are no longer cooled because of the insulating effect of a vapor film.

Thus, despite the lower heat capacity to water, oil may be the more suitable cooling medium, even if a smaller amount of heat can be dissipated at the same volume flow. When using oil as the cooling medium, a continuous cooling effect without vapor bubbles is ensured even at high temperatures.

For modern engine concepts in which the cooling water circuit is initially in warm-up operation of the engine, a cooling circuit realized in the oil circuit can be advantageous for particularly temperature-critical engine areas such as the land area, since the cooling effect can be ensured in any operating condition with the engine running, thus minimizing the critical web growth becomes.

Further advantageous embodiments of the invention will become apparent from the subclaims and the following description of preferred embodiments of the present invention.

There are embodiments in which the fluid channel is formed in the valve-near high-temperature region of the cylinder (in particular directly below the top deck). In this range, the temperature load is maximum and the cooling effect due to the high temperature difference between the cylinder interior and the cooling fluid best. Overheating of the web material as well as changes in geometry or thermal stresses caused by local temperature increases are thus effectively reduced.

There are embodiments in which the fluid channel is formed as a bore in a mechanical machining process. Thus, very narrow channels with high precision in comparatively narrow, thin-walled (low remaining wall thickness between adjacent cylinders) web areas can be realized.

There are embodiments in which the fluid channel in each case connects two oil-conducting tie-rod bores extending in an inclined plane. In such an embodiment, existing channels for the oil circuit can be used without the need for additional cavities in the engine component would have to be provided. The tie rod bore can also be used as a supply channel to guide the oil for cooling from the main oil gallery in the cylinder crankcase into the cylinder head, where it is passed through the fluid channel through the land area to the opposite tie rod bore. Thereafter, the oil is directed back into the cylinder crankcase to the main bearings where it is used for lubrication of the main and connecting rod bearings.

There are embodiments in which one of the oil-carrying Zugankerbohrungen has an oil-carrying groove into which the fluid channel opens. By this measure, the delivery volume can be increased in the tie rod bore, without the bore cross section would have to be increased overall. Even with eccentric absorption of the tie rods in Zugankerbohrungen so a sufficient supply of oil is ensured.

There are embodiments in which the fluid channel is formed in a pressurized region of the oil channel system. Thus, the oil is guided for cooling with the available delivery pressure through the fluid channel. Thus, a defined volume flow and thus also over the cross section and the delivery volume definable heat transfer in the web area can be realized.

There are versions in which the engine component is designed as a cylinder crankcase. Here, the temperature problem in the upper web area - especially with very thin webs - particularly pronounced and the cooling effect there also correspondingly effective.

There are embodiments in which the fluid channel is then formed between a piston ring region of a piston located in an upper piston inversion point and a top deck of the cylinder crankcase. The top deck of the cylinder crankcase represents the parting line to the cylinder head or to the cylinder head gasket. Between this level and above the addressed piston ring area, the highest thermal loads due to the combustion process in the cylinder are to be expected. At the same time, no mechanical stress is to be expected here due to the piston rings resting on the cylinder wall, so that a fluid duct extending here is thermally very effective and mechanically represents only a reduced risk; even with a very small remaining wall thickness between the interior of the fluid channel and the actual cylinder bore. So occur in any possible deformations no frictional disadvantages, since the piston rings do not attack (more) on the inner wall of the cylinder during operation.

There are also embodiments in which a fluid channel as part of the oil circuit and a further fluid channel are arranged in common as part of the cooling water circuit. Such a double cooling can improve and differentiate the cooling effect. In the warm-up phase - in other words, if the cooling water circuit is possibly stationary - the engine oil flowing through cools in any case. In normal operation after warming up or at a very high load additionally cools the second fluid channel in the cooling water circuit. Due to the additional partial or pre-cooling through the oil circuit while the risk of overheating of the cooling water is reduced in this high temperature range, so that there is reduced the risk of vapor or gas bubbles or a decomposition of cooling water components.

In an embodiment in which a fluid channel is provided in the cooling water circuit, it is ensured by a suitable throttling of the cooling water flow in the water jacket of the cylinder crankcase that a sufficient volume flow through the fluid channels in the land areas out (parallel cross-flow).

There are also embodiments in which the engine component is designed as a cylinder head. Cooling of the web area can also be advantageous in such an embodiment since, as an alternative or in addition to a corresponding embodiment in the cylinder crankcase, the "hot" area of the cylinder can additionally be cooled and the material and operational risks mentioned are reduced.

Furthermore, the invention relates to an internal combustion engine with an engine component according to the invention or a vehicle with such an internal combustion engine.

Fig. 1

einen Querschnitt (Lage entspricht der Ebene B-B in Fig. 3) durch ein erfindungsgemäßes Zylinderkurbelgehäuse in einer Stegebene zeigt,

Fig. 2

Detail A aus Fig. 1 mit einem Fluidkanal als Bestandteil des Ölkreislaufes und einem optionalen Fluidkanal als Bestandteil des Kühlwasserkreislaufes,

Fig. 3

eine Ansicht von oben auf das Topdeck eines anderen erfindungsgemäßen Zylinderkurbelgehäuses,

Fig. 4

eine Schnittdarstellung C-C des in Fig. 3 dargestellten Zylinderkurbelgehäuses,

Fig. 5

eine schematische Schnittdarstellung eines erfindungsgemäßen Zylinderkopfes mit Ölkühlung;

Fig. 6

eine schematische Schnittdarstellung eines erfindungsgemäßen Zylinderkopfes mit Wasserkühlung und

Fig. 7

eine schematische Darstellung eines Fahrzeugs mit einem Motor mit einer erfindungsgemäßen Motorkomponente

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which

Fig. 1

a cross section (position corresponds to the plane BB in Fig. 3 ) by a cylinder crankcase according to the invention in a bank level,

Fig. 2

Detail A off Fig. 1 with a fluid channel as part of the oil circuit and an optional fluid channel as part of the cooling water circuit,

Fig. 3

a top view of the top deck of another cylinder crankcase according to the invention,

Fig. 4

a sectional view CC of in Fig. 3 illustrated cylinder crankcase,

Fig. 5

a schematic sectional view of a cylinder head according to the invention with oil cooling;

Fig. 6

a schematic sectional view of a cylinder head according to the invention with water cooling and

Fig. 7

a schematic representation of a vehicle with a motor with an engine component according to the invention

An embodiment of an engine component according to the invention, which is designed as a cylinder crankcase 1, show the Fig. 1 - 4th ,

The Fig. 1 and 2 show a cross section through the cylinder crankcase 1 in the web area 2 between the two cylinders 3 (see Fig. 4 ). The section plane corresponds to that in Fig. 3 shown section plane BB. The web portion 2 extends between the two cylinders 3 of a group, which are arranged in a row. It runs parallel to the cylinder axes 4 and between the also extending parallel to the cylinder axes 4 Zugankerbohrungen 5a, 5b, which extend from the top deck 6 to (not shown) counter flange of the (also not shown) crankshaft bearing.

The tie rod hole 5a shown on the right is connected to the main oil gallery 7 of the oil passage system formed in the cylinder crankcase 1. The Zugankerbohrung 5a is at its side with an oil-carrying groove 9 (see Fig. 2 ), which ensures a sufficient flow of oil even with an arranged in the Zugankerbohrung 5a tie rod and low oil temperatures at elevated viscosity.

Instead of the optional groove 9 in the tie rod bore 5a, the required oil flow can also be ensured by a suitable choice of the ratio between the tie rod diameter (smaller) and the diameter (larger) of the tie rod bore 5b. The tie rod 5b is connected at its lower end via an oil passage 10 with one of the crankshaft main bearings. In the upper area just below the top deck 6 connects an oil-carrying fluid channel 12, the two Zugankerbohrungen 5a and 5b.

The tie rod holes 5a and 5b, the main oil gallery 7, the oil passage 10 and the fluid channel 12 are part of the pressure oil system and are formed either during casting in the cylinder crankcase 1 (for example by inserting corresponding casting cores) and / or in mechanical processing methods (such as drilling , Rooms, etc.).

In operation, the engine oil flows through the main oil gallery 7 in the tie rod hole 5a, there - possibly in the groove 9 - on, flows through the fluid channel 12 and is through the Zugankerbohrung 5b led to the oil passage 10, where it then exits into the sliding bearing gap of the crankshaft bearing. In this case, the oil flowing through the fluid channel 12 cools the web region 2 between the cylinders 3, in particular in the upper region, in which the highest temperatures occur during operation due to the combustion occurring there.

In the illustrated embodiment, the fluid channel 12 is formed in the web region 2 in a mechanical machining process (bore). This is done by the in Fig. 1 and 2 initially shown a bore 13 a from the motor outside first introduced into a Sprühölbereich 14, then a further bore 13 b (possibly with reduced diameter) between Sprühölbereich 14 and Zugankerbohrung performed and finally 5 - again reduced diameter - the fluid channel 12 in the web area. 2 drilled. Thereafter, the holes 13a and 13b are closed by appropriate Verkugelungen 15. This prevents a connection of the oil-carrying tie rod hole 5a with the spray oil region 14 or out of the engine.

In other embodiments, not shown, the number of Verkugelungen be reduced by a shift of Sprühölkanäle.

For a web width b (see. Fig. 3 ) of about 7 mm, the diameter of the fluid channel 12 is about 3 mm. The course of the fluid channel 12 is chosen so that it is located between the top deck 6 and the piston ring position, which occupy the piston rings when the piston is at its upper piston reversal point.

Alternatively or in addition to the above-described web cooling in the oil passage system, such web cooling can also be designed optionally or additionally in the cooling water system.

For this purpose, the cooling pockets 20 which are arranged on each side of the cylinders and extend into the web region 2 (cf. Fig. 1 and 2 ) is connected to a fluid passage 22 so that cooling water also flows through the land portion 2.

In the Fig. 1 and 2 illustrated with solid lines embodiment of the fluid channel 22 with a circular cross-section 22a is also introduced by drilling from the outside, which are closed at the appropriate places with Verkugelungen 25 so that cooling water can not get either outside or in the oil circuit. Such a design is feasible even with very small web widths.

At higher web widths, a fluid channel 22 with a more effective cooling cross section 22 b can be carried out, which is poured into the cylinder crankcase 1. This cooling cross section 22b has, for example, an oval or lenticular shape, so that the effective cooling surfaces are increased to the cylinders 3. Advanced casting techniques also allow very small core dimensions and radii. This can possibly also be formed very narrow fluid channels in narrow, thin-walled web areas.

The illustrated water cooling via the fluid channel 22 with the alternative cooling cross-sections 22a and 22b may be formed either alone or in addition to the cooling via the oil-carrying fluid channel 12 (see. Fig. 1 and 2 ).

The 3 and 4 show a slightly differently designed, inventive cylinder crankcase 1, in which an exclusive water cooling of the web portion 2 is carried out immediately below the top deck 6.

FIGS. 5 and 6 show an engine component designed as a cylinder head 101, in which the web region 102 between adjacent cylinders 3 is provided, for cooling purposes, with a fluid channel 112 or 122 connected to the oil circuit either via the tie rod bores 105a, 105b. Fig. 6 ) or via connecting channels 126 with core pockets 120 of the cylinder head 101 and thus connected to the cooling water circuit, and during operation of the engine by a cooling medium (eg., Cooling water or oil) is flowed through.

The fluid channels are either formed in a casting process or mechanically processed and optionally sealed with Verkugelungen 15, 25. In the FIGS. 6 and 7 illustrated concepts can also be combined. Thus, additional web cooling in the cylinder head 101 can also be carried out with the cooling concepts of the web areas 2 (only oil, oil / water, water only) shown above for the cylinder crankcase 1.

Fig. 7 shows a schematic representation of a vehicle 40 with an internal combustion engine 30 with an engine component 1 according to the invention

LIST OF REFERENCE NUMBERS

1

cylinder crankcase

2

web region

3

cylinder

4

cylinder axis

5a, 5b

Zugankerbohrung

6

Topdeck

7

Main oil gallery

8th

- free -

9

groove

10

oil passage

11

Main bearing

12

fluid channel

13a

drilling

13b

drilling

14

Sprühölbereich

15

Verkugelung (ÖI)

20

cool bag

22

fluid channel

22a

Cross section (round)

22b

Cross-section (oval)

25

Verkugelung (water)

30

internal combustion engine

40

vehicle

101

cylinder head

102

web region

103

cylinder

105a, 105b

Zugankerbohrung

112

fluid channel

120

core pocket

122

fluid channel

126

connecting channel

Claims (11)

Engine component (1; 101) of a reciprocating engine with
a group of several juxtaposed cylinders (3), between each of which a web region (2; 102) extends,
at least one fluid channel (12; 22; 112; 122) extending in the web region (2; 102) between two adjacent cylinders (2), in particular transversely to a cylinder axis (4), comprising a first and a second region (5a, 5b; 120) of a fluid channel system, such that during operation of the reciprocating motor fluid from the first region (5a; 20; 105a; 20) through the fluid channel (12; 22; 112; 122) into the second region (5b; 20; 105b; 120), thereby removing heat from the cylinders (3) via the land area (2; 102) and cooling the land area (2; 102), the fluid channel (12; 112) having first and second Area (5a, 5b, 105a, 105b) connects an oil channel system. The engine component (1; 101) of claim 1, wherein the fluid channel (12; 22; 112; 122) is formed in the high-temperature region of the cylinder (3) close to the valve. The engine component (1; 101) of claim 1 or 2, wherein the fluid channel (12; 22; 112; 122) is formed as a bore in a mechanical machining process. Engine component (1; 101) according to claim 1, 2 or 3, wherein the fluid channel (12) in each case connects two oil-carrying tie rod bores (5a, 5b; 105a, 105b) running in an inclined plane. An engine component (1; 101) according to claim 4, wherein at least one of said tie-bolt bores (5a, 5b; 105a, 105b) has an oil-carrying groove (9; 109) into which said fluid passage (12) opens. An engine component (1; 101) according to any one of the preceding claims, wherein the fluid passage (12, 112) is formed in a pressure region of the oil passage system. Engine component (1) according to one of the preceding claims, which is designed as a cylinder crankcase (1). Engine component (1) according to claim 7, wherein the fluid channel (12) between a piston ring portion of a located in an upper piston reversal point piston and a top deck (6) of the cylinder crankcase (1) is formed. Engine component (101) according to one of claims 1 to 6, which is designed as a cylinder head (101). Internal combustion engine (30) with an engine component (1; 101) according to one of the preceding claims. Vehicle (40) with an internal combustion engine (30) according to claim 10.

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