MONOBLOC PISTON FOR DIESEL ENGINES

• US 20030037671A1
• Filed: 08/24/2001
• Published: 02/27/2003
• Est. Priority Date: 08/24/2001
• Status: Active Grant

• Current Assignee: Federal-Mogul World Wide LLC (Apollo Global Management, Inc.)
• Original Assignee: Federal-Mogul Worldwide Incorporated (Apollo Global Management, Inc.)
• Inventors: Gaiser, Randall R., Zhu, Xiluo
• Granted Patent: US 6,526,871 B1
• Time in Patent Office: Days
• US Class Current: 92/231
• 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 3/003 the parts being connected by casting, brazing, welding or clamping

Abstract

A steel monobloc piston for diesel engines is formed with a relatively short piston skirt whose lower edge resides below the axis of the pin bores of the piston, but located at or above a lowest tangent point of the pin bores. The piston body preferably has a closed oil cooling gallery and the skirt is preferably joined at its upper end to an outer wall of the piston in which a plurality of ring grooves are formed.

Claims

1. A piston for diesel engines, comprising:

a piston body fabricated of steel;

said piston body having an outer wall and a closed oil gallery;

a pair of pin bosses having pin bores formed therein, said pin bores having a common pin bore axis and a lowest tangency point;

a skirt formed as one piece with the pin bosses, said skirt coupled at an upper end to said outer wall; and

said piston skirt having a lower edge disposed below said pin bore axis and located at or above said lowest tangency point of said pin bores.

2. The piston of claim 1 wherein said piston body includes the following dimensional ratios:

(H/D)=0.5-0.75 (A/D)=0.3-0.6 (A/H)=0.7-1.2

where,

H=compression height of the piston body between a top of the piston and the axis of the pin bores,

D=piston diameter, and

A=axial length between the lowest ring groove and the lower edge of piston skirt.

3. The piston of claim 1 wherein said piston body is fabricated of at least two separate parts which are connected across at least one joint.

4. The piston of claim 3 wherein said at least one joint comprises a friction weld joint.

5. A piston for a diesel engine, comprising:

a piston body fabricated of steel;

a pair of pin bosses having aligned pin bores disposed about a pin bore axis and having a lowest tangent point of said pin bores;

a skirt formed as one piece with said pin bores and having a lower edge disposed below said pin bore axis and at or above said lowest tangent point of said pin bores.

6. A diesel engine comprising:

an engine block having at least one cylinder bore;

a monobloc piston disposed in said cylinder bore having a piston body fabricated of steel and having a pair of pin bosses with aligned pin bores disposed about a pin bore axis and having a lowest tangent point of said pin bores; and

a piston skirt formed as one piece with said pin bosses, said skirt having a lower edge disposed below said pin bore axis at or above said tangent point of said pin bores.

7. The diesel engine of claim 6 wherein said piston body includes the following dimensional ratios:

(H/D)=0.5-0.75 (A/D)=0.3-0.6 (A/H)=0.7-1.2

where,

H=compression height of the piston body between a top of the piston and the axis of the pin bores,

D=piston diameter, and

A=axial length between the lowest ring groove and the lower edge of the piston skirt.

8. The diesel engine of claim 6 wherein the cylinder has a lower edge and said lower edge of said piston skirt is disposed at or above said lower edge of said cylinder when said piston is at a lowest point of travel in said cylinder.