A piston for internal combustion diesel engine having a piston diameter of 180 to 650 mm, includes a top part and a body part connectable to each other, the top part defining, when installed in a cylinder of the engine, the piston side of a combustion chamber, and the body part having an aperture for a gudgeon pin, bosses for distributing forces, when in use, between the piston and the gudgeon pin, the body part having an interior, an outer surface and operable connecting surfaces. The interior of the body part includes an interior wall having a macro geometry of wavy surface, where a wave has a length of 3 to 25 mm and a height of 0.3 to 3 mm, the wavy surface having a micro geometry measurable as a surface roughness of 5 to 9 μm.

The present invention relates to a multi-piece, in particular at least two-piece, piston (1) for an internal combustion engine having a longitudinal axis (L), comprising a piston outer part (10) having a closed piston head (11), which in the fitted state defines a combustion chamber, and a piston body (13) extending axially away from the piston head (11), and a piston inner part (20), which in the fitted state is connected to a connecting rod. An outer surface (2) radially defining the piston (1) is formed exclusively by at least one portion of the piston body (13) of the piston outer part (10). The piston inner part (20), viewed in an axial direction, is arranged radially entirely inside the piston body (13) or its circumferential surface.

A method is provided for designing and producing fiber-reinforced polymer (FRP) pistons. Pistons made with FRP have a lower mass than prior art metal pistons conferring advantageous engine efficiency and stability. FRP pistons also increase the thermal efficiency of engines by having a lower thermal conductivity, with tighter piston-to-bore clearance, and/increased air-fuel ratio than pistons of metal. The technical parameters of the piston are identified, and a piston body blank is produced. The blank is then machined, a bearing surface for the pin bore is created, the piston blank is optionally coated, is optionally subjected to Heavy Metal Ion Implantation (HMII) treatment and is subjected to sodium silicate impregnation to produce the final pistons.

A method is provided for designing and producing fiber-reinforced polymer (FRP) pistons. Pistons made with FRP have a lower mass than prior art metal pistons conferring advantageous engine efficiency and stability. FRP pistons also increase the thermal efficiency of engines by having a lower thermal conductivity, with tighter piston-to-bore clearance, and/increased air-fuel ratio than pistons of metal. The technical parameters of the piston are identified, and a piston body blank is produced. The blank is then machined, a bearing surface for the pin bore is created, the piston blank is optionally coated, is optionally subjected to Heavy Metal Ion Implantation (HMII) treatment and is subjected to sodium silicate impregnation to produce the final pistons.

A piston, particularly a piston for use in a diesel engine, particularly a heavy duty diesel engine, is formed from a billet of metal, such that the finished piston has a mass that is at least 50%, and, more preferably, up to about 62%, of the mass of the billet. Other than finishing steps, the piston is formed with a closed gallery, without loss of mass through machining processes.

A piston, particularly a piston for use in a diesel engine, particularly a heavy duty diesel engine, is formed from a billet of metal, such that the finished piston has a mass that is at least 50%, and, more preferably, up to about 62%, of the mass of the billet. Other than finishing steps, the piston is formed with a closed gallery, without loss of mass through machining processes.

The present invention relates to a method for producing a piston (1) for an internal combustion engine from a piston upper part (2) and a piston lower part (3).

The method has the following method steps: producing a piston upper part (2) having a piston top (6), at least parts of a ring section (12) and at least part (7) of a cooling channel (8), by forging or casting for example, producing the piston lower part (3) and closing the part (7) of the cooling channel (8) which is arranged in the piston upper part (2) by means of an additive method, finish-machining the piston (1), including the production of at least one annular groove (4) in the ring support (5) for receiving a piston ring.

In this way, it is possible to provide a piston (1) that has a greater strength in its piston upper part (2), which is subjected to high thermal and mechanical loads, than in its piston lower part (3), which is subjected to lower thermal and mechanical loads, and that permits greater freedom of manufacture in respect of the shape of the piston lower part (3).

The present invention relates to a method for producing a piston (1) for an internal combustion engine from a piston upper part (2) and a piston lower part (3).

The method has the following method steps: producing a piston upper part (2) having a piston top (6), at least parts of a ring section (12) and at least part (7) of a cooling channel (8), by forging or casting for example, producing the piston lower part (3) and closing the part (7) of the cooling channel (8) which is arranged in the piston upper part (2) by means of an additive method, finish-machining the piston (1), including the production of at least one annular groove (4) in the ring support (5) for receiving a piston ring.

In this way, it is possible to provide a piston (1) that has a greater strength in its piston upper part (2), which is subjected to high thermal and mechanical loads, than in its piston lower part (3), which is subjected to lower thermal and mechanical loads, and that permits greater freedom of manufacture in respect of the shape of the piston lower part (3).

Provided is a piston push rod assembly which can prevent discomfort from being imparted during the operation of a brake pedal by a driver. A piston push rod assembly, wherein: a second piston is provided with a piston slide section which is housed in a cylinder and which slides relative to the cylinder, and a connection tube section which is connected to a push rod; the piston slide section is covered by metal plating; the connection tube section has a non-plated section; and the second piston and the push rod are connected by the caulking of the connection tube section when the push rod has been inserted inside the connection tube section.

Provided is a piston push rod assembly which can prevent discomfort from being imparted during the operation of a brake pedal by a driver. A piston push rod assembly, wherein: a second piston is provided with a piston slide section which is housed in a cylinder and which slides relative to the cylinder, and a connection tube section which is connected to a push rod; the piston slide section is covered by metal plating; the connection tube section has a non-plated section; and the second piston and the push rod are connected by the caulking of the connection tube section when the push rod has been inserted inside the connection tube section.