Piston for internal combustion engines, especially diesel engines

• US 5,605,126 A
• Filed: 02/06/1996
• Issued: 02/25/1997
• Est. Priority Date: 08/11/1993
• Status: Expired due to Fees

• Current Assignee: Alcoa Deutschland GmbH (Howmet Aerospace, Inc.)
• Original Assignee: Alcoa Deutschland GmbH (Howmet Aerospace, Inc.)
• Inventors: Hofmann, Lothar, Schwarz, Rudolf, Obermeier-Wagner, Karl-Heinz, Deuber, Andreas
• Primary Examiner(s): Nelli, Raymond A.
• Application Number:
  US08/596,013
• Time in Patent Office: 385 Days
• Field of Search: 123/276, 123/260, 123/302, 123/661, 123/262, 123/261, 123/257, 123/269, 123/279, 123/256, 92/208, 92/222
• US Class Current: 123/276
• CPC Class Codes: F02B 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02B 23/0672 Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis the surrounding wall being exactly vertical F02B23/0696
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02F 3/00 Pistons
• CPC Class Codes: F02F 3/28 Other pistons with specially-shaped head
• CPC Class Codes: F05C 2201/021 Aluminium
• CPC Class Codes: F05C 2201/0448 Steel
• CPC Class Codes: F05C 2201/0466 Nickel
• CPC Class Codes: F05C 2201/0475 Copper or alloys thereof
• CPC Class Codes: F05C 2201/0487 Manganese
• CPC Class Codes: F05C 2201/903 Aluminium alloy, e.g. AlCuMgPb F34,37
• CPC Class Codes: F16J 1/00 Pistons; Trunk pistons; Plungers bellows pistons F16J3/06; piston-rings or seats therefor F16J9/00; manufacture of pistons B23P15/10; rotary pistons, e.g. for "Wankel" type engines F01C; specific for combustion engines, i.e. constructed to withstand high temperature or modified for guiding, igniting, vaporising or otherwise treating the charge F02F; pistons for hydraulic engines F03C; pumps F04B; floats F16K33/00
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A piston for diesel engines is made of a toughness-increasing aluminium alloy containing copper, nickel, silicon, magnesium, iron and manganese. The use of this material, which can conventionally be chill-cast, and by implying special dimensions, provides a piston which, despite its relatively light construction, provides the utmost security against cracking in the stressed regions, e.g. the piston boss or the combustion chamber recess.

Claims

1. A piston for internal combustion engines, especially diesel engines, including

a piston diameter D,

a compression height KH,

a combustion chamber recess (10) with a diameter MN and a depth MT,

a pin bore (14) with a diameter B,

a radially inner spacing AA of the piston pin bosses above the piston pin axis,

a piston pin length SA,

a length SL of the piston body beneath the lowermost piston ring groove (12),

a body wall thickness WDDS(X) on the thrust side in the connecting rod pivoting plane X,

a body wall thickness WDGDS(X) on the counter-pressure side in the connecting rod pivoting plane X,

the body wall thicknesses WDDS(X) and WDGDS(X) continuously decreasing in an angular area α

between the connecting rod pivoting plane X and the piston pin plane Y from Y in the direction of X, and

the mentioned dimensions lying within the following ranges;

KH=(0.48 to 0.63)×

D

MT=(0.16 to 0.35)×

D

MN=(0.40 to 0.62)×

D

B=(0.29 to 0.41)=D

AA=(0.24 to 0.43)×

D

SA=(0.70 to 0.86)×

D

SL=(0.25 to 0.45)×

D

WDDS (X)=(0.030 to 0.065)×

D

WDGDS (X)=(0.023 to 0.047)×

D, and

the body wall thicknesses in the angular area α

decreasing from the piston pin plane Y in the direction of the connecting rod pivoting plane X according to the following dimension rules;

from (0.09 to 0.06)×

D to (0.065 to 0.030)×

D on the thrust side, and

from (0.09 to 0.06)×

D to (0.047 to 0.023)×

D on the counter-thrust side.

2. A piston according to claim 1, in which the angular area α

is smaller or equal to 10°

.

3. A piston according to claim 1, in which the piston has the following dimensions:

D=81 mm

KH=0.56 D

MT=0.21 D

MN=0.54 D

B=0.32 D

AA=0.27 D

SA=0.83 D

SL=0.32 D

WDDS(X)=0.052 D

WDGDS(X)=0.027 D.

4. A piston according to claim 1 which is produced from an alloy consisting in percentages by weight of:

2% to 6% copper

2% to 6% nickel

11 to 16% silicon

0.5 to 2.0% magnesium

less than 0.7% iron

less than 0.5% manganese

the sum of the impurities is less than 0.15%

the rest is aluminium

and preferably

3.3 to 4.0% copper

2.2 to 3.0% nickel

11.0 to 12.0% silicon

0.8 to 1.3% magnesium.

5. A piston according to claim 4, which is produced according to the chill-casting process.

6. A piston according to claim 2 in which the piston has the following dimensions:

D=81 mm

KH=0.56 D

MT=0.21 D

MN=0.54 D

B=0.32 D

AA=0.27 D

SA=0.83 D

SL=0.32 D

WDDS (X)=0.052 D

WDGDS (X)=0.027 D.

7. A piston according to claim 2 which is produced from an alloy consisting in percentages by weight of:

2% to 6% copper

2% to 6% nickel

11 to 16% silicon

0.5 to 2.0% magnesium

less than 0.7% iron

less than 0.5% manganese

the sum of the impurities is less than 0.15%

the rest is aluminum

and preferably

3.3 to 4.0% copper

2.2 to 3.0% nickel

11.0 to 12.0% silicon

0.8 to 1.3% magnesium.

8. A piston according to claim 3 which is produced from an alloy consisting in percentages by weight of:

2% to 6% copper

2% to 6% nickel

11 to 16% silicon

0.5 to 2.0% magnesium

less than 0.7% iron

less than 0.5% manganese

the sum of the impurities is less than 0.15%

the rest is aluminum

and preferably

9. 3 to 4.0% copper

2.2 to 3.0% nickel

11.0 to 12.0% silicon

0.8 to 1.3% magnesium.