Articulated piston with a cooling recess having a preestablished volume therein

A steel piston member including an upper portion and a lower portion for reciprocatable movement in a combustion chamber engine comprising:

• the upper portion being substantially cylindrical in shape and having a peripheral top surface, a tubular wall depending from the top surface, an outwardly facing wall portion and a downwardly facing annular cooling recess;
• the lower portion including a pair of depending pin bosses blendingly associated with the outwardly facing wall portion;
• and
• at least one baffle plate positioned in the recess and fixedly sealingly attached to the tubular wall and the outwardly facing wall portion of the upper portion of the piston member in heat conducting relationship forming a cooling gallery having a preestablished trapped volume and at least one opening therein.

An articulated piston assembly including a piston member and a skirt portion adapted for use in an engine comprising:

• the piston member having an upper portion and a lower portion;
• said upper portion being substantially cylindrical in shape and having a peripheral top surface, a tubular wall depending from the top surface, an outwardly facing wall portion and a downwardly facing annular cooling recess;
• and said lower portion including a pair of depending pin bosses blendingly associated with the outwardly facing wall portion, said pin bosses individually defining a wrist pin receiving bore aligned on a central axis;
• the skirt portion positioned about the lower portion of the piston member and having a pair of wrist pin receiving bores aligned with the central axis;
• a wrist pin disposed in the pair of wrist pin receiving bores of the skirt and the wrist pin receiving bores in the lower portion of the piston member attaching the skirt to the piston member;
• and
• at least one baffle plate positioned in the annular cooling recess and fixedly sealingly attached to the upper portion of the piston member in heat conducting relationship forming a cooling gallery having a preestablished trapped volume and at least one opening therein, said preestablished trapped volume has a range of from about 50% to about 75% of the total cooling recess volume.

A steel piston member including an upper portion and a lower portion for reciprocatable movement in a combustion chamber engine comprising:

• the upper portion being substantially cylindrical in shape and having a peripheral top surface, a tubular wall depending from the top surface, an outwardly facing wall portion and a downwardly facing annular cooling recess;
• the lower portion including a pair of depending pin bosses blendingly associated with the outwardly facing wall portion;
• and
• at least one baffle plate positioned in the recess and fixedly sealingly attached to the upper portion of the piston member in heat conducting relationship forming a cooling gallery having a preestablished trapped volume and at least one opening therein, said preestablished trapped volume has a range of from about 50% to about 75% of the total cooling recess volume.