DE102020124998A1 - Method for repairing a crankcase of an internal combustion engine and motor vehicle - Google Patents

Abstract

A method for repairing a crankcase of an internal combustion engine, comprising the steps of:- providing a crankcase comprising at least one cylinder bore, the cylinder bore having a coating;- removing the coating;- activating the cylinder bore;- coating the cylinder bore following activation; Removing the separating surface of the crankcase oriented toward a cylinder head and providing a cylinder head for arrangement on the crankcase, the cylinder head having an oversize to compensate for the removed separating surface.

Description

The present invention relates to a method for repairing a crankcase of an internal combustion engine and a motor vehicle.

Cylinder bores of modern crankcases often have coatings that form the actual cylinder running surface. Such coatings are applied, for example, by means of thermal spraying methods such as arc wire spraying. If there are problems with the coating of any kind, for example during the production of the crankcase or in connection with engine damage or if the engine has reached its maximum service life, it is common today to dispose of the crankcase, since treatment or .Repair appears to be too expensive. This is due in particular to the intensive bonding of the coating with the material of the crankcase. the DE 10 2013 200 912 A1 therefore proposes the use of cylinder liners, which should not extend to a sealing or separating surface of the crankcase, so that the cylinder bore between the separating surface and the liner consists of the basic material of the crankcase. In the present case, however, the use of cylinder liners should be dispensed with.

It is therefore an object of the present invention to specify a method for repairing a crankcase and a motor vehicle, in which case coated crankcases in particular can be repaired in a process-reliable and cost-efficient manner.

This object is achieved by a method according to claim 1 and by a motor vehicle according to claim 13. Further advantages and features emerge from the subclaims and the description and the attached figure.

• - Bereitstellen eines Kurbelgehäuses, umfassend zumindest eine Zylinderbohrung, wobei die Zylinderbohrung eine Beschichtung aufweist;
• - Entfernen der Beschichtung;
• - Aktivieren der Zylinderbohrung;
• - Beschichten der Zylinderbohrung im Anschluss an die Aktivierung;
• - Abtragen der zu einem Zylinderkopf hin orientierten Trennfläche des Kurbelgehäuses und Bereitstellen eines Zylinderkopfs zur Anordnung an dem Kurbelgehäuse, wobei der Zylinderkopf ein Aufmaß zur Kompensation der abgetragenen Trennfläche aufweist.

According to the invention, a method for repairing a crankcase, preferably made of a light metal such as aluminum and/or magnesium, of an internal combustion engine comprises the steps:

• - providing a crankcase comprising at least one cylinder bore, the cylinder bore having a coating;
• - removing the coating;
• - activation of the cylinder bore;
• - Coating of cylinder bore following activation;
• - Removal of the separating surface of the crankcase oriented towards a cylinder head and providing a cylinder head for arrangement on the crankcase, the cylinder head having an oversize to compensate for the removed separating surface.

Surprisingly, it has been found that the use of a special cylinder head makes it possible to repair a crankcase in a particularly cost-effective and nevertheless very effective manner. The work steps carried out on the crankcase itself are advantageously designed in such a way that after they have been carried out, a crankcase is provided which has no qualitative differences from a new (uncoated) crankcase. This means that there is a (bare) cylinder bore that can be processed in the same way as in series production, for example by activating and coating. The parting surface is removed, for example ground down, so that it does not differ from that of a "new" crankcase. This is made possible by the use of a cylinder head, which advantageously equalizes or compensates for the material removal at the parting surface.

• - Entfernen der Beschichtung, wobei ein Durchmesser der Zylinderbohrung dabei zumindest so weit vergrößert wird, dass die zumindest eine Einlauffase entfernt wird;
• - Einbringen einer neuen Einlauffase.

According to one embodiment, the at least one cylinder bore has at least one inlet chamfer, which is formed on the parting surface or in the transition to it, and the method comprises the steps:

• - Removing the coating, wherein a diameter of the cylinder bore is increased at least to such an extent that the at least one inlet chamfer is removed;
• - Introduction of a new inlet chamfer.

The aforementioned method steps can be transferred in the same way to a run-out chamfer of the cylinder bore, which is also advantageously removed.

Advantageously, the foregoing steps ensure that a smooth cylindrical surface is provided for activation.

According to one embodiment, the oversize of the cylinder head is adjusted during the mechanical processing of the cylinder head. According to one embodiment, a new cylinder head is used. The cylinder head is preferably a cast component. Compared to a series cylinder head, the cylinder head sealing surface is expediently machined with an allowance that is dimensioned in such a way that the abrasion on the separating surface of the crankcase is compensated. The Verdich The performance ratio is appropriately not affected in any way during repairs. The processing is carried out, for example, by grinding. A cylinder head gasket is arranged between the parting surface and the cylinder head sealing surface. Their strength/thickness can also be increased compared to the standard version in order to compensate for the wear on the parting surface. The method also includes the step of locating/attaching the cylinder head. If the cylinder head is manufactured using additive manufacturing, for example, the oversize can be taken into account directly during manufacture.

According to one embodiment, the oversize of the cylinder head is already set or kept available when the cylinder head blank is cast. This is particularly advantageous if the allowance to be set is rather large.

• - Vollflächiges Abtragen der Trennfläche in einem Bereich von etwa 0,1 bis 1,5 mm, bevorzugt in einem Bereich von etwa 0,3 bis 1,2 mm, insbesondere bevorzugt in einem Bereich von etwa 0,5 bis 1 mm.

According to one embodiment, the method comprises the step:

• - Full-area removal of the parting surface in a range of about 0.1 to 1.5 mm, preferably in a range of about 0.3 to 1.2 mm, particularly preferably in a range of about 0.5 to 1 mm.

It has been found that these dimensions can be easily implemented in practice and can therefore be implemented in a process-reliable and cost-efficient manner.

• - Abtragen der alten Beschichtung bis das blanke Material des Kurbelgehäuses freiliegt.

According to one embodiment, the method comprises the step:

• - Remove the old coating until the bare material of the crankcase is exposed.

Expediently, the existing layer/coating is worked out, whereby the preferred methods can be called boring or high-pressure water jets. This creates a "pure, clean" cylinder in aluminum, with a cylinder bore diameter that is approx. 0.2 to 1.5 mm larger than originally, preferably between 0.3 and 0.8 mm.

• - Einstellen eines Nenndurchmessers der Zylinderbohrung über eine Anpassung der Dicke der neuen Beschichtung.

According to one embodiment, the method comprises the step:

• - Setting a nominal cylinder bore diameter by adjusting the thickness of the new coating.

Expediently, the previous material removal is compensated by the newly applied coating. Accordingly, the new coating may be slightly thicker than the original coating.

According to a preferred embodiment, the new coating has a thickness in a range of about 0.35 mm to 0.9 mm in radius, preferably in a range of about 0.4 mm to 0.8 mm, more preferably in a range of about 0.5 to 0.6 mm. The above values ensure that the coating has good adhesion and does not come off.

• - Beschichten durch thermisches Spritzen, insbesondere Lichtbogendrahtspritzen oder Kaltgasspritzen.

According to a preferred embodiment, the method comprises the step:

• - Coating by thermal spraying, in particular arc wire spraying or cold gas spraying.

The aforementioned methods are sufficiently known from the prior art and are therefore not described in more detail here. Before coating, the cylinder bore is expediently activated. Activation is understood to mean a processing of the cylinder bore which serves to improve adhesion of the layer/coating or to ensure it in the required manner at all.

For example, a preferred method for activation is high pressure water jetting. The high-pressure water blasting can be used to remove the old coating at the same time, so that when using this technology, a separate activation process can conveniently be dispensed with. A micro-geometry can be created by means of high-pressure water jets, which enables the coating to be clamped to the material of the crankcase. While high-pressure water jetting is no longer used in the series production of crankcases for reasons of economy and environmental protection, in this case it can certainly bring advantages due to the small quantities.

According to an alternative embodiment, activation takes place by means of grooving the cylinder bore and subsequent rolling. When grooving, a groove structure is introduced into the cylinder bore, with such a groove structure or groove running helically or thread-like along a cylinder axis according to one embodiment. According to one embodiment, a multiplicity of circular grooves, which are oriented perpendicularly to the cylinder axis and are sawn, cut or milled into the material of the crankcase, are provided over the entire length of the cylinder bore. During the subsequent roller burnishing, the webs produced in connection with the grooves are reshaped in such a way that undercuts are formed on the webs, as a result of which clamping with the coating material can be achieved. The created are particularly advantageous The webs are additionally roughened on their surface, whereby a micro form fit is achieved in addition to the macro form fit (cf. the undercuts).

Preferred coating materials are based on iron. Preferred materials for the crankcase are aluminum materials. The crankcase is expediently produced by die casting or also by means of permanent mold casting or low-pressure casting. The cylinder head is preferably produced using a low pressure gravity casting or sand casting process.

• - Einbringen einer neuen Einlauffase in die Zylinderbohrung.

According to one embodiment, the method comprises the step:

• - Introduction of a new inlet chamfer in the cylinder bore.

The running-in chamfer can correspond to the original running-in chamfer in terms of its geometry or it can also have a new geometry.

Basically, with regard to the inlet bevel, it should be noted that this can also be a multi-stage bevel, for example a double bevel. According to one embodiment, the inlet chamfer comprises a first chamfer and at least one second chamfer, which are formed adjacent to one another and differ in their angle. The chamfers can be flat or even or rounded.

• - Einbringen einer neuen Einlauffase in die neue Beschichtung und das umgebende Material des Kurbelgehäuses.

According to one embodiment, the method comprises the step:

• - Introduction of a new run-in chamfer in the new coating and the surrounding material of the crankcase.

Expediently, the new inlet chamfer, like preferably also the original inlet chamfer, is formed in such a way that it extends into the material of the crankcase. This has advantages with regard to the processing of the separating surface, since it can be ensured that the coating is not processed in an impermissible manner when the separating surface is subsequently processed.

• - Einbringen einer (neuen) Auslauffase an der Zylinderbohrung.

Conveniently, the method includes the step:

• - Introduction of a (new) run-out chamfer on the cylinder bore.

The run-out chamfer serves as a honing run-out. This is preferably machined away when the coating is worked out or when the cylinder bore is activated again, similar to the inlet chamfer.

Since the new coating has a greater wall thickness than the original one, the inlet chamfer and the outlet chamfer are expediently also dimensioned larger, for example 10 to 20%.

The invention further relates to a motor vehicle comprising an internal combustion engine which has a crankcase which has been repaired according to one of the preceding claims. According to a preferred embodiment, the motor vehicle is a motorcycle, a commercial vehicle or, in particular, a passenger car. The internal combustion engine or the crankcase of the internal combustion engine advantageously comprises at least one cylinder or at least one cylinder bore, expediently three, four, six, eight, ten or twelve, the number of cylinders or cylinder bores having no influence on the use of the method.

Further advantages and features result from the following description of an embodiment of a process sequence with reference to the attached figure.

• 1: mehrere schematische Ansichten eines Kurbelgehäuses zur Veranschaulichung einer Ausführungsform des Verfahrens.

It shows:

• 1 1: several schematic views of a crankcase to illustrate an embodiment of the method.

1 12 shows a plurality of views of a cylinder bore 20 of a crankcase 10 arranged one above the other along a cylinder axis A in order to explain an embodiment of the method for repairing a crankcase. Only half of the cylinder bores 10 are shown in each case along the common cylinder axis A. The top view shows that the crankcase 10 has a parting surface 12 . A cylinder head (likewise not shown) is arranged on the parting surface 12 indirectly via a cylinder head gasket, which is not shown here. The cylinder bore 10 includes an inlet chamfer 22. A running surface is formed by a coating 24 which is applied directly to the material of the crankcase 20, for example by means of a thermal spraying process, which is expediently an aluminum material.

For the repair, the running surface 30 is removed in a method step s1, for example by means of boring or high-pressure water jets, the inlet chamfer 22 being removed at the same time. The result is a "pure" and "clean" cylinder in aluminum with a diameter that is approx. 0.1 to 0.3 mm larger than the original diameter, see reference number 34.

In method step s2, a new coating 26 is applied, expediently also by means of a thermal spraying process such as arc wire spraying or cold gas spraying. In a previous step, not shown here, the cylinder bore is activated, for example by means of high-pressure water jets and/or a combination of grooving and rolling. The coating 26 is possibly slightly thicker than the original coating 24 in order to compensate for the previous material removal. If the original coating 24 has a thickness of about 350 μm, for example, the new coating 26 has a thickness of about 550 μm, for example.

In method step s3, a new inlet chamfer 28 is set, with this being dimensioned in such a way that it extends from the new coating 26 into the material of the crankcase 10. In order to remove any coating residues and contaminants or damage to the separating surface 12, the latter is removed, in particular, for example, ground off, with the material removal being outlined using the reference symbol x. The separating surface is therefore somewhat lower than the original separating surface, for example by up to 1 mm lower, depending on the embodiment.

In step s4, the separating surface 12 is lowered accordingly. A new running surface 32 is expediently produced by means of honing. What is not shown here is that similar to a new inlet chamfer 28 at the other end of the cylinder bore 10, a corresponding outlet chamfer is also incorporated as a honing outlet. By using a correspondingly designed cylinder head, the aforementioned machining of the parting surface 12, cf. the reference symbol x, is expediently compensated.

Reference List

10

crankcase

12

interface

20

cylinder bore

22

inlet bevel

24

(old) coating

26

(new) coating

28

new inlet phase

30

old tread

32

new tread

34

bare crankcase material

x

removal

A

cylinder axis

s1, s2, s3, s4

process steps

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• DE 102013200912 A1 [0002]

Claims (13)

Method for repairing a crankcase (10) of an internal combustion engine, comprising the steps: - Providing a crankcase (10) comprising at least one cylinder bore (20), wherein the cylinder bore (20) has a coating (24); - removing the coating (24); - Activate the cylinder bore (20); - Coating of the cylinder bore (20) following the activation; - Removing the separating surface (12) of the crankcase (10) oriented toward a cylinder head and providing a cylinder head for arrangement on the crankcase (10), the cylinder head having an oversize to compensate for the removed separating surface (12). procedure after claim 1 , wherein the cylinder bore (20) has at least one inlet chamfer (22), comprising the steps: - removing the coating (24), a diameter of the cylinder bore (20) being increased at least to such an extent that the at least one inlet chamfer (22) Will get removed; - Introduction of a new inlet chamfer (28). procedure after claim 1 or 2 , whereby the oversize of the cylinder head is set during the mechanical processing of the cylinder head. Method according to one of the preceding claims, in which the oversize of the cylinder head is set/reserved when the blank is cast. Method according to one of the preceding claims, comprising the step: - Full-area removal of the parting surface (12) in a range from 0.1 to 1.5 mm, preferably in a range from 0.3 to 1.2 mm, particularly preferably in a range from 0.5 to 1.0 mm. Method according to one of the preceding claims, comprising the step: - Remove the old coating (24) until the bare material (34) of the crankcase (10) is exposed. Method according to one of the preceding claims, comprising the step: - Setting a nominal diameter of the cylinder bore (20) by adjusting the thickness of the new coating (26). A method according to any one of the preceding claims, wherein the new coating (26) has a thickness in the range 0.35 to 0.9 mm. Method according to one of the preceding claims, comprising the step: - Coating by thermal spraying, in particular arc wire spraying or cold gas spraying. Method according to one of the preceding claims, comprising the step: - Introduction of the inlet chamfer (28) in the new coating (26) and the surrounding material of the crankcase (10). Method according to one of the preceding claims, comprising the step: - Activate by grooving and rolling. Method according to one of the preceding claims, comprising the step: - Introduction of a run-out chamfer. Motor vehicle comprising an internal combustion engine having a crankcase (10) which has been repaired according to any one of the preceding claims.

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