Air compressor housing for an air compressor of a commercial vehicle, method of producing such a compressor and use of a hypereutectic aluminium alloy therefore

Abstract

The invention relates to an air compressor housing (1) for an air compressor of a commercial vehicle, wherein the air compressor is configured to supply pressurized air to a pneumatic system of the vehicle, the air compressor housing (1) comprising a crankshaft portion (5) configured to support a crankshaft that is configured to rotate about a crankshaft axis, and a cylinder housing portion (3), wherein the cylinder housing portion (3) has an inner wall (19) configured to slidably support a piston head to move up and down along the inner wall (19) of the cylinder housing portion (3) in the direction of a stroke axis (S), wherein the inner wall (19) comprises or consists of a hypereutectic aluminium alloy. It is suggested that the hypereutectic aluminium alloy contains one or both of the following alloying components: Copper (Cu) at 1.0 wt% or less, Magnesium (Mg) at 1.5 wt% or more.

Description

[0001] Air compressor housing for an air compressor of a commercial vehicle, method of producing such a compressor and use of a hypereutectic aluminium alloy therefore

[0002] The present invention relates to an air compressor housing for an air compressor of a commercial vehicle, wherein the air compressor is configured to supply pressurized air to a pneumatic system of the vehicle, the housing comprising a crankshaft portion configured to support a crankshaft that is configured to rotate about a crankshaft axis, and a cylinder housing portion, wherein the cylinder housing portion has an inner wall configured to slidably support a piston head to move up and down along the inner wall of the cylinder housing portion in the direction of a stroke axis, wherein the inner wall comprises or consists of a hypereutectic aluminium alloy.

[0003] In the automotive industry in general, and in the commercial vehicle industry in particular, there is an increasing demand for reducing carbon dioxide emissions across vehicle fleets. In this regard, it is an established approach to strive for weight reduction across the entire vehicle which may lead to lower fuel consumption and thus a reduction in emissions. Manufacturers have been following this route by employing light weight alloys wherever possible. In particular, manufacturers have been attempting to replace cast iron material by aluminium, or other nonferrous metal alloys.

[0004] In the sector of air compressors, it is known from DE 10 2014 013442 A1 to manufacture the air compressor housing from an aluminium alloy. DE 10 2014 013 442 A1 suggests using a number of aluminium alloys, namely Al Si9 Cu3 (F2), Al Si 12 Cu Ni Mg, or a hypereutectic aluminium alloy Al Si 17 Cu4 Mg.

[0005] While the aforementioned known alloy has been found to work generally well for the dedicated use as material of an air compressor housing, further improvements are still desired. In particular, there is a desire to improve the wear resistance of the air compressor housing, in particular in the region of the cylinder housing portion.

[0006] Thus, it was an object of the invention to improve the air compressor housing of the type mentioned herein above, in particular with regard to wear resistance.

[0007] The invention achieves the object by suggesting, for an air compressor housing of the type mentioned initially, to employ a hypereutectic aluminium alloy which contains at least one, and preferably both, of the following alloying components:

[0008] Copper at 1 .0 wt% or less,

[0009] Magnesium at 1 .5 wt% or more,

[0010] Nickel at 0.5 wt% or more.

[0011] It shall be understood that in the listing above and in the listings that will ensue, aluminium and inevitable impurities make up the rest of the alloy composition to reach 100 wt%.

[0012] It has been found that using the above-mentioned quantities of alloying components, either separately or together, has a positive effect on the material’s hardness and wear resistance. The increased hardness compared to prior art aluminium alloys which were previously used for air compressor housings, is a result of improving the configuration of silicon depositions inside the material, the formation of which is influenced by the alloying components.

[0013] In a preferred embodiment, the hypereutectic aluminium alloy contains, preferably in addition to Copper as specified in particular hereinabove, Nickel (Ni) at 0.5 wt% or more. Combining nickel with the above alloy compoments, and in particular at least with copper, provides increased strength at elevated temperatures. In a further preferred embodiment, the copper content of the hypereutectic aluminium alloy is in a range from 0.85 wt% to 1 .0 wt%, preferably from 0.9 wt% to 1 .0 wt%.

[0014] In a further preferred embodiment, the magnesium content is between 1 .5 wt% and 2.0 wt%, preferably between 1 .75 wt% and 1 .95 wt%.

[0015] In a further preferred embodiment, the nickel content is between 0.5 wt% and 1 .0 wt%, preferably between 0.6 wt% and 0.8 wt%, further preferred in a range between 0.65 wt% and 0.75 wt% and particularly preferred at 0.712 wt%.

[0016] In a further preferred embodiment, the hypereutectic aluminium alloy contains silicon at less than 17 wt%, preferably in range of 15.9 wt% to 16.1 wt%, further preferred in a range of 16.0 wt% to 16.05 wt%.

[0017] In a further preferred embodiment, the hypereutectic aluminium alloy contains iron at 1 .0 wt% or less, preferably at 0.25 wt% or less, further preferred between 0.15 wt% and 0.2 wt%.

[0018] In a further preferred embodiment, the hypereutectic aluminium alloy contains traces of one, more or all of the following components: Titanium (Ti), zirconium (Zn), tin (Sn), lead (Pb), preferably each at less than 0.1 wt%, further preferred at less than 0.05 wt%.

[0019] In a further preferred embodiment, the hypereutectic aluminium alloy contains manganese as an alloying component at more than 0.3 wt%, preferably in a range of 0.4 to 0.75 wt%.

[0020] In a further preferred embodiment, the inner wall of a cylinder housing portion comprises a honed surface, the honed surface having one, more or all of the following surface characteristics: - a Core Roughness (RK) in a range of 1 .0 gm to 2.0 gm, preferably in a range of 1.6 to 1.8 pm,

[0021] - a Reduced Peak Height (RPk) of 0. 8 pm or less,

[0022] - a Reduced Valley Depth (RVk) in a range of 0.4 pm to 4.0 pm, preferably in a range of 0.9 pm to 1 .2 pm,

[0023] - a smallest material ratio (Mn) in a range of 12% or less, preferably in a range of 6% to 10% at the upper limit of the roughness core area,

[0024] - a greatest material ratio (Mr2) in a range of 55% to 88%, preferably in a range of 85 % to 87% at the lower limit of the roughness core area,

[0025] - a Honing Angle (a) in a range of 20° to 30°, preferably in a range of 24° to 26°.

[0026] Herein, the terminology used above for the surface characteristics and the underlying way of measuring shall be understood as implemented in accordance with ISO 13565-2.

[0027] It has been found that by honing the surface of the inner wall to the above- mentioned surface characteristics, in particular in combination with the hypereutectic aluminium alloy of the preferred embodiments described further above, the surface obtains a surface structure which contains a beneficial isolation of Si particles, wherein the shape, size and concentration of the Si particles leads to an improved wear resistance compared to prior art aluminium alloys such as the ones discussed in DE 10 2014 013 442 A1.

[0028] In a further preferred embodiment, the crankshaft portion and the cylinder housing portion are integrally formed, preferably cast in one piece. After curing of the cast material, the alloy according to the invention has been found to already produce a beneficial hardness and still allows for surface processing such as honing as described in preferred embodiments herein above. Further improvements in hardness may be achieved, in a preferred embodiment, if the aluminium alloy is subjected to heat treatment. In particular, the aluminium alloy preferably is subjected to a multi-phase heat treatment. In a preferred embodiment, the aluminium alloy is subjected in a first phase to a quenching procedure which comprises solutionizing the alloy at a temperature of 525 °C + / - 5°C for a time interval of 5 to 7 hours, preferably 6 hours, and subsequently quenching the alloy, preferably in water or a water-containing medium.

[0029] Further preferably, the aluminium alloy is then subjected in a second phase to age hardening, i.e. precipitation hardening, which comprises heating the alloy to 160°C + / -10 °C for 5 to 7 hours, preferably for 6 hours, before cooling the alloy, preferably by air.

[0030] In a further preferred embodiment, the cylinder housing portion comprises a first plurality of outwardly protruding ribs that extend circumferentially around the housing portion, and a second plurality of outwardly protruding ribs that extend longitudinally along the housing portion, at least substantially parallel to the stroke axis defined by the cylinder housing portion. Under substantially parallel, according to the invention a deviation of 0° + / - 2° relative to the stroke axis, i. e. alternatively 1 °+ / - 1°, shall be understood as within range of being parallel.

[0031] In a further preferred embodiment, the crankshaft portion comprises a plurality of outwardly protruding ribs that extend longitudinally along the crankshaft portion, at least substantially parallel to the crankshaft axis, defined by the crankshaft portion.

[0032] The ribs described herein above for the cylinder housing portion and the crankshaft portion beneficially serve a dual function, namely acting as cooling ribs on the one hand side while at the same time also acting as additional reinforcement structure to minimize unwanted deformation of the air compressor housing under load and temperature. In a further preferred embodiment, the cylinder housing portion comprises a distal end in relation to the crankshaft portion, the distal end in other words being the end of the cylinder housing portion which is most remote to the crankshaft portion, and a total length in the direction of the stroke axis extending from the crankshaft axis to the distal end, wherein the distal end comprises a flange having a flange thickness in the longitudinal direction of the stroke axis in a range of 11 % to 15 %, preferably of 13 % of the total length.

[0033] The invention has hereinabove been described in a first aspect with respect to the air compressor housing itself. In a second aspect, the invention also relates to a method of producing an air compressor housing, in particular an air compressor housing according to any one of the preferred embodiments described herein above.

[0034] The method of the second aspect achieves the object initially stated by comprising the steps of casting a molten hypereutectic aluminium alloy, e.g. into a mould, and curing the cast hypereutectic aluminium alloy, e.g. in the mould, wherein the hypereutectic aluminium alloy contains at least one, and preferably both, of the following alloying components:

[0035] - Copper (Cu) at 1 .0 wt% or less,

[0036] - Magnesium (Mg) at 1 .5 wt% or more.

[0037] The benefits achieved with the air compressor housing of the first aspect are at the same time also benefits of the method of the second aspect. Preferred embodiments of the air compressor housing of the first aspect are at the same time also preferred embodiments of the method of the second aspect and vice versa which is why reference is made to the description above to avoid unnecessary repetition. In particular, the hypereutectic aluminium alloy used in the method of the second aspect has the characteristics as described herein above relating to the first aspect.

[0038] In a preferred embodiment, the housing comprises a cylinder housing portion, wherein the cylinder housing portion has an inner wall configured to slidably support a piston head, and the method comprises the step of honing a surface of the inner wall such that the surface obtains one, more or all of the following characteristics:

[0039] - a Core Roughness (RK) in a range of 1 .0 pm to 2.0 pm, preferably in a range of 1.6 to 1.8 pm,

[0040] - a Reduced Peak Height (RPk) of 0. 8 pm or less,

[0041] - a Reduced Valley Depth (RVk) in a range of 0.4 pm to 4.0 pm, preferably in a range of 0.9 pm to 1 .2 pm,

[0042] - a smallest material ratio (Md) in a range of 12% or less, preferably in a range of 6% to 10% at the upper limit of the roughness core area,

[0043] - a greatest material ratio (Mr2) in a range of 55% to 88%, preferably in a range of 85 % to 87% at the lower limit of the roughness core area,

[0044] - a Honing Angle (a) in a range of 20° to 30°, preferably in a range of 24° to 26°.

[0045] Preferably, the honing is performed with a flex honing tool, the tool in particular comprising a silicon carbide head, and by using a set of operating parameters, wherein the operating parameters include one, more or all of the following: a honing tool grit (G) in a range of 120 to 240, preferably of 180, a rotation speed (Sr)in a range of 800 rpm to 1200 rpm, preferably at 1000 rpm, a, preferably vertical, stroke feed (fs) in a range of 20 mm / s to 40 mm / s, preferably at 25 mm / s. In a further aspect, the invention also relates to a use of a hypereutectic aluminium alloy containing at least one, preferably both, of the following alloying components:

[0046] Copper (Cu) at 1 .0 wt% or less,

[0047] Magnesium (Mg) at 1 .5 wt% or more, to produce an air compressor housing of an air compressor for a commercial vehicle, in particular an air compressor housing of any one of the preferred embodiments described herein above with respect to the first aspect.

[0048] The use preferably is implemented within a method as described herein above for the second aspect.

[0049] The use according to the third aspect shares the benefits and preferred embodiments of the first and second aspects, and vice versa, which is why again reference is made to the description herein above to avoid unnecessary repetition.

[0050] A particularly preferred hypereutectic aluminium alloy for use in each of the three aspects discussed hereinabove contains the following alloying components:

[0051] - Copper (Cu) at 1 .0 wt% or less, preferably in a range between 0.9 wt% and 1.0 wt%

[0052] - Magnesium (Mg) at 1 .0 wt% or more, preferably between 1 .75 wt% and

[0053] 1 .95 wt%, and

[0054] - Nickel (Ni) at 0.5 wt% or more, preferably between 0.6 wt% and 0.8 wt%. It shall be understood that aluminium and traces of further components, such as unavoidable impurities and exemplarily, but not restricted to, the further components mentioned hereinabove, form the rest of the composition to reach 100 wt%. The invention will hereinafter be explained in more detail by referring to a preferred embodiment and according to the attached figures, wherein:

[0055] Fig. 1 shows a schematic three-dimensional view of an air compressor housing according to a preferred embodiment, and

[0056] Fig. 2 shows a schematic overview of a method for producing the air compressor housing of Fig. 1 .

[0057] Fig. 1 shows an air compressor housing 1 for an air compressor which is configured to be used in a commercial vehicle (not shown). The air compressor housing 1 (herein after also: housing) comprises a crankshaft portion 3 and a cylinder housing portion 5. The crankshaft portion 3 and the cylinder housing portion 5 are integrally formed in a one-piece design. The crankshaft portion defines a rotational axis R for a crankshaft (not shown) and the cylinder housing portion defines a longitudinal stroke axis S for the direction of movement of a reciprocating piston head (not shown).

[0058] The stroke axis S is orthogonal to the rotational axis R. Measured from the rotational axis R, the cylinder housing portion extends until a total length Ltotai in the direction of the stroke axis S. The cylinder housing portion 5 comprises a distal end 7 which defines the most remote end of the cylinder housing portion 5 from the crankshaft portion 3 in the direction of the stroke axis S. The distal end 7 comprises a flange 9 having a thickness t. The thickness t is defined as a ratio of 13 % of the total length Ltotai. The flange 9 comprises a plurality of bores 11 , preferably threaded, for mounting a cylinder head to the cylinder housing portion 5 of the air compressor housing 1 .

[0059] On the periphery of the distal end 7, the flange 9 comprises at least one, and preferably a plurality of, inwardly extending recesses 12 which are configured to reduce the weight of the air compressor housing 1 . Below and above the recesses 12, material ribs extending from edge to edge of the distal end 7 are preferably provided to reinforce the flange 9 of the cylinder housing portion 5.

[0060] Below the distal end, the cylinder housing portion 5 comprises a cylindrical outer wall 17 and a first plurality of circumferentially extending ribs 13 projecting therefrom. Additionally, the cylinder housing portion 5 comprises a second plurality of ribs 15 which extend substantially parallel to the stroke axis S and are distributed circumferentially along the outer wall 17. The first plurality of ribs 13 and the second plurality of ribs 15 preferably intersect one another, creating a web of ribs. The ribs 13, 15 in the cylinder housing portion preferably have a dual function of acting as cooling elements on the one hand side by reinforcing the overall surface area of the cylinder housing portion, and as reinforcement elements on the other hand side to limit the radial expansion and other distortions of the cylinder housing portion under mechanical and temperature load.

[0061] Since the cylindrical housing portion 5 is configured to slidingly support a piston head on its inside, it comprises an inner wall 19 having a surface 20 against which the piston slides when mounted.

[0062] The crankshaft portion 3 comprises, preferably on opposite end sides, a mounting interface 21 for receiving a crankshaft cover (not shown).

[0063] A plurality of ribs 25 extend outwardly on the crankshaft portion 3, parallel as shown here, at least substantially parallel, to the rotational axis R. The ribs 25 preferably also doubly act as reinforcement elements against distortion and as cooling elements like the plurality of ribs 13, 15 above.

[0064] The crankshaft portion 3 comprises a plurality of bores 27, preferably threaded, for mounting a crankshaft cover thereto. The overall structure of the air compressor housing 1 shown in Fig. 1 is optimized for casting the air compressor housing in one piece. Alternatively, it would also be possible to cast the cylinder housing portion 5 and the crankshaft portion 3 separately and joining the parts subsequently, for example by welding.

[0065] In accordance with one aspect of the invention, casting is a preferred way of producing the air compressor housing, wherein in particular, an AlSi 16 alloy shall be used which will be discussed further below.

[0066] As is exemplarily shown in Fig. 2, the air compressor housing 1 of Fig. 1 may be produced by casting in step 101 the hypereutectic aluminium alloy into a mould.

[0067] In step 103, the aluminium alloy is cured to obtain the raw body of the air compressor housing 1.

[0068] In step 105, the surface 20 of the inner wall 19 of the cylinder housing portion 5 is subjected to honing, preferably to flex honing. Beneficially, a silicon carbide tool head is used for this.

[0069] The honing preferably is conducted by using a tool grit G of 180, a rotational speed Sr of 1000 rpm, and a stroke feed fsof 25 mm / s.

[0070] Preferably, the hypereutectic aluminium alloy that is used for casting has the following composition:

[0071] Si: 16 wt%, Cu: 1 .0 wt%, Mg: 1 .9 wt%, Fe: 0.2 wt%, Ni: 0.7 wt%, wherein aluminium and unavoidable impurities form the rest of the composition so as to reach 100 wt%.

[0072] By using this particular alloy and the operating parameters for the honing above, the surface 20 of the inner wall 19 in the cylinder housing portion 15 is obtained with surface characteristics as follows: Rk 1 .7 pm

[0073] Rpk 0.6 pm

[0074] Rvk 1 .0 pm

[0075] Mr1 8.0 %

[0076] Mr2 86.0 %

[0077] The honing angle a is preferably selected at 25.0°.

[0078] A hardness test for the aforementioned aluminium alloy is conducted under DIN EN ISO 6506-1 :2015. A test force of 750 kg was applied using a ball probe having a diameter of 5 mm. The hardness observed is in a range of 131 -135 BHN. The wear resistance on the surface 20 of the inner wall 19 of the cylinder housing portion 5 has been found to be vastly improved over other hypereutectic aluminium alloys such as, in particular, AISi17 Cu4Mg.

[0079] The comparative prior art AISi17 Cu4Mg alloy has the following composition as specified in EN 1706:

[0080] Si: 16-18 wt%, Cu: 4-5 wt%, Mn: max. 0.5 wt%, Mg: 0.25-0.65 wt%, Fe: max.

[0081] 1 .3 wt%, Ni: max. 0.3 wt%, Sn: max. 0.15 wt%, Ti: max. 0.25 wt%, Zn: max. 1 .5 wt%, and aluminium and unavoidable impurities forming the rest. The observed Brinell hardness using the same method as above for the inventive alloy was in the range of 120 BHN.

[0082] As has been documented herein above, the invention suggests an air compressor housing and a method for its production which achieve a significant weight reduction of over 50% with respect to using cast iron in a similar structure.

[0083] At the same time, the invention allows to achieve an improved hardness, bringing the material characteristics of the air compressor housing closer to those of cast iron housings, which to this day still suffered from a higher material hardness at the cost of higher weight.

[0084] List of reference signs (Part of the description)

[0085] I air compressor housing

[0086] 3 cylinder housing portion

[0087] 5 crankshaft portion

[0088] 7 distal end

[0089] 9 flange

[0090] I I bore, flange

[0091] 12 recess

[0092] 13 circumferential rib

[0093] 15 longitudinal rib, cylinder housing portion

[0094] 17 outer wall, cylinder housing portion

[0095] 19 inner wall

[0096] 20 surface, inner wall

[0097] 21 crankshaft bore

[0098] 25 ribs, crankshaft portion

[0099] 27 mounting bores, crankshaft cover

[0100] Ltotai length t thickness

[0101] R rotational axis, crankshaft portion

[0102] S stroke axis, cylinder housing portion

[0103] P operating parameter

[0104] G tool grit

[0105] Sr rotational speed fsstroke feed

[0106] Rk core roughness

[0107] RPk reduced peak height

[0108] Rvk reduced valley depth

[0109] MM smallest material ratio

[0110] Mr2 greatest material ratio a honing angle

Claims

Claims1 . An air compressor housing (1 ) for an air compressor of a commercial vehicle, wherein the air compressor is configured to supply pressurized air to a pneumatic system of the vehicle, the air compressor housing (1) comprising- a crankshaft portion (5), wherein the crankshaft portion (5) is configured to support a crankshaft that is configured to rotate about a crankshaft axis, and- a cylinder housing portion (3), wherein the cylinder housing portion (3) has an inner wall (19) configured to slidably support a piston head to move up and down along the inner wall (19) of the cylinder housing portion (3) in the direction of a stroke axis (S), wherein the inner wall (19) comprises or consists of a hypereutectic aluminium alloy, characterized in that the hypereutectic aluminium alloy contains at least one, and preferably both, of the following alloying components:- Copper (Cu) at 1 .Owt% or less,- Magnesium (Mg) at 1 .5 wt% or more.

2. The air compressor housing of claim 1 , characterized in that the hypereutectic aluminium alloy contains, preferably in addition to Copper,- Nickel (Ni) at 0.5 wt% or more.

3. The air compressor housing (1) of claim 1 , characterized in that the copper content is between 0.85 wt% and 1 .0 wt%, preferably between 0.9 wt% and 1 .0 wt%.

4. The air compressor housing (1) of claim 1 or 2, characterized in that the magnesium content is between 1 .5 wt% and 2.0 wt%, preferably between 1 .75 wt% and 1 .95 wt%.

5. The air compressor housing (1) of any one of the preceding claims,characterized in that the nickel content is between 0.5 wt% and 1 .0 wt%, preferably between 0.6 wt% and 0.8 wt%, further preferred in a range between 0.65 wt% and 0.75 wt%.

6. The air compressor housing (1) of any one of the preceding claims, characterized in that the hypereutectic aluminium alloy contains silicon (Si) at less than 17 wt%, preferably in range of 15.9 wt% to 16.1 wt%, further preferred in a range of 16.0 wt% to 16.05 wt.

7. The air compressor housing (1) of any one of the preceding claims, characterized in that the hypereutectic aluminium alloy contains iron (Fe) at 1 .0 wt% or less, preferably at 0.25 wt% or less, further preferred between 0.15 wt% and 0.2 wt%.

8. The air compressor housing of any one of the preceding claims, wherein the hypereutectic alloy contains traces of one, more or all of the following components:- titanium (Ti),- zirconium (Zn),- tin (Sn),- lead (Pb), preferably each at less than 0.1 wt%, further preferred at less than 0.05 wt%.

9. The air compressor housing (1) of any one of the preceding claims,- characterized in that the hypereutectic aluminium alloy contains manganese (Mn) as an alloying component at more than 0.3 wt%, preferably in a range of 0.4 to 0.75 wt%.

10. The air compressor housing (1) of any one of the preceding claims, characterized in that the inner wall (19) comprises a surface (20), the surface (20) having one, more or all of the following surface characteristics:- a Core Roughness (RK) in a range of 1 .0 gm to 2.0 gm, preferably in a range of 1.6 to 1.8 pm,- a Reduced Peak Height (RPk) of 0. 8 pm or less,- a Reduced Valley Depth (RVk) in a range of 0.4 pm to 4.0 pm, preferably in a range of 0.9 pm to 1 .2 pm,- a smallest material ratio (Mn) in a range of 12% or less, preferably in a range of 6% to 10% at the upper limit of the roughness core area,- a greatest material ratio (Mr2) in a range of 55% to 88%, preferably in a range of 85 % to 87% at the lower limit of the roughness core area,- a Honing Angle (a) in a range of 20° to 30°, preferably in a range of 24° to 26°.11 . The air compressor housing (1 ) of any one of the preceding claims, wherein the crankshaft portion (5) and the cylinder housing portion (3) are integrally formed, preferably cast in one piece.

12. The air compressor housing (1) of any one of the preceding claims, wherein the cylinder housing portion (3) comprises a first plurality of outwardly protruding ribs (13) that extend circumferentially around the cylinder housing portion (3), and a second plurality of outwardly protruding ribs (15) that extend longitudinally along the cylinder housing portion (3), at least substantially parallel to the stroke axis (S) defined by the cylinder housing portion (3).

13. The air compressor housing (1) of any one of the preceding claims, wherein the crankshaft portion (5) comprises a plurality of outwardly protruding ribs (25) that extend longitudinally along the crankshaft portion (5), at least substantially parallel to the crankshaft axis defined by the crankshaft portion (5).

14. The air compressor housing (1) of any one of the preceding claims, characterized in that the cylinder housing portion (3) comprises a distal end (7) in relation to the crankshaft portion (5), and a total length (Ltotai) in the direction of the stroke axis (S) extending from the rotational axis (R) to the distal end,wherein the distal end comprises a flange having a flange thickness (t) in the longitudinal direction of the stroke axis (S) in a range of 11% to 15 %, preferably of 13 % of the total length.

15. A method of producing an air compressor housing (1 ), in particular an air compressor housing (1) of any one of the preceding claims, the method comprising the steps of casting (101) and curing (103) a hypereutectic aluminium alloy, characterized in that the hypereutectic aluminium alloy contains at least one, and preferably both, of the following alloying components:- Copper (Cu) at 1 .0 wt% or less,- Magnesium (Mg) at 1 .5 wt% or more.

16. The method of claim 15, wherein the air compressor housing (1) comprises a cylinder housing portion (3), wherein the cylinder housing portion (3) has an inner wall (19) configured to slidably support a piston head, and the method comprises the step of honing (105) a surface (20) of the inner wall (19) such that the surface (20) obtains one, more of all of the following characteristics:- a Core Roughness (RK) in a range of 1 .0 pm to 2.0 pm, preferably in a range of 1.6 to 1.8 pm,- a Reduced Peak Height (RPk) of 0. 8 pm or less,- a Reduced Valley Depth (RVk) in a range of 0.4 pm to 4.0 pm, preferably in a range of 0.9 pm to 1 .2 pm,- a smallest material ratio (Mn) in a range of 12% or less, preferably in a range of 6% to 10% at the upper limit of the roughness core area,- a greatest material ratio (Mr2) in a range of 55% to 88%, preferably in a range of 85 % to 87% at the lower limit of the roughness core area,- a Honing Angle (a) in a range of 20° to 30°, preferably in a range of 24° to 26°.

17. The method of claim 16, wherein the honing (105) is performed, preferably with a flex honing tool comprising a silicone carbide head, by using a set of operating parameters (P), wherein the operating parameters (P) include one, more or all of the following:- a honing tool grit (G) in a range of 120 to 240, preferably of 180,- a rotation speed (sr)in a range of 800 rpm to 1200 rpm, preferably at 1000 rpm,- a, preferably vertical, stroke feed (fs) in a range of 20 mm / s to 40 mm / s, preferably at 25 mm / s.

18. A use of a hypereutectic aluminium alloy containing one or both of the following alloying components:- Copper (Cu) at 1 .0 wt% or less,- Magnesium (Mg) at 1 .0 wt% or more, to produce an air compressor housing (1) of an air compressor for a commercial vehicle, in particular an air compressor housing (1) of any one of the preceding claims.

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