ANTI-CAVITATION DIESEL CYLINDER LINER

• US 20060249105A1
• Filed: 09/13/2005
• Published: 11/09/2006
• Est. Priority Date: 09/14/2004
• 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: Azevedo, Miguel
• Granted Patent: US 7,146,939 B2
• Time in Patent Office: Days
• US Class Current: 123/41.840
• CPC Class Codes: F02F 1/12 Preventing corrosion of liquid-swept surfaces
• CPC Class Codes: F02F 1/16 Cylinder liners of wet type

Abstract

A wet-style cylinder liner (16) for a diesel engine is provided with a surface texture (28) to combat the effects of cavitation-induced erosion. The surface texture (28) can be formed as a coating (30) of manganese phosphate applied about the outer surface (26) of the cylinder liner (16) within the coolant flow passage (20) of the engine. The manganese phosphate is applied in such a manner that a crystalline structure of 2-8 μm average grain size, blocky in nature, clearly faceted, with no cauliflower-like formations and a discernable channel network surrounding the crystals is formed. This crystalline structure works with the natural adhesion and surface tension effects within the liquid coolant to create a stagnant fluid layer about the outer surface (26) of the cylinder liner (16). The stagnant fluid layer functions like a self-healing armor plate. When rapid flexing of the cylinder liner (16) produces cavitation bubbles, these bubbles are held at a distance from the outer surface (26) by the stagnant fluid layer. As the bubbles implode, their kinetic energy is dissipated within the stagnant fluid layer instead of directly upon the outer surface (26) of the cylinder liner (16). The manganese phosphate coating (30) acts as a labyrinth to anchor water molecules, or the engine coolant, and thus promote formation of the stagnant fluid layer.

Claims

1. A cylinder liner for a liquid-cooled internal combustion engine, said cylinder liner comprising:

a tubular body having a generally cylindrical bore adapted for receiving a reciprocating piston and forming a portion of the chamber in which the thermal energy of a combustion process is converted into mechanical energy;

a upper end;

a lower end;

an outer surface enveloping said tubular body and extending between said upper and lower ends, at least a portion of said outer surface adapted for direct contact with a liquid cooling medium to transfer heat energy from said liner into the liquid cooling medium; and

at least a portion of said outer surface including a surface texture consisting essentially of blocky particles having an average size of 2-8 μ

m, said particles being each faceted and surrounded by a channel network.

2. The cylinder liner of claim 1 wherein said tubular body is composed of a first material and said surface texture comprises a coating composed of a second material dissimilar to said first material.

3. The cylinder liner of claim 2 wherein said coating includes manganese phosphate.

4. The cylinder liner of claim 3 wherein said coating consists essentially of Mn₅H₂(PO₄)₄—

4H₂O.

5. The cylinder liner of claim 1 wherein the maximum distance between adjacent ones of said particles is less then 8 μ

m.

6. A liquid-cooled cylinder block for an internal combustion engine, said block comprising:

a crank case including a coolant flow passage;

a cylinder liner disposed in said crank case, said cylinder liner having a generally tubular body defining bore extending between upper and lower ends thereof;

said body of said cylinder liner including an outer surface at least partially exposed to said coolant flow passage for transferring heat energy from said liner to a liquid cooling medium flowing within said coolant flow passage; and

at least a portion of said outer surface exposed to said coolant flow passage including a surface texture consisting essentially of crystalline grains having an average size of 2-8 μ

m, said grains being each faceted and surrounded by a channel network.

7. The cylinder liner of claim 6 wherein said tubular body is composed of a first material and said surface texture comprises a coating composed of a second material dissimilar to said first material.

8. The cylinder liner of claim 7 wherein said coating includes manganese phosphate.

9. The cylinder liner of claim 8 wherein said coating consists essentially of Mn₅H₂(PO₄)₄—

4H₂O.

10. The cylinder liner of claim 6 wherein the maximum distance between adjacent ones of said crystalline grains is less than 8 μ

m.