A connecting rod for a variable compression internal combustion engine, the connecting rod including a crank bearing eye for connecting the connecting rod with a crank shaft; a connecting rod bearing eye configured to connect the connecting rod with a cylinder piston of the internal combustion; an eccentrical element adjustment arrangement configured to adjust an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes an eccentrical element that cooperates with an eccentrical element lever, wherein the eccentrical element is configured to receive a wrist pin of the cylinder piston, wherein the eccentrical element adjustment arrangement includes at least one cylinder with a piston that is displaceably supported in a cylinder bore hole and connected with a support rod, wherein the eccentrical element lever includes two eccentrical element lever segments which are connected by at least one connecting bolt to which the support rod is pivotably connected.

The invention relates to a method for work-hardening a crankshaft (4) comprising connecting rod journals (5), main bearing journals (6) and crank webs (7), the connecting rod journals (5) and the main bearing journals (6) being provided with oil holes (31). According to the invention, at least one end (30) of one of the oil holes (31) and/or at least one cylindrical portion (38) of the oil holes (31) is/are work-hardened.

The invention relates to a method for work-hardening a crankshaft (4) comprising connecting rod journals (5), main bearing journals (6) and crank webs (7), the connecting rod journals (5) and the main bearing journals (6) being provided with oil holes (31). According to the invention, at least one end (30) of one of the oil holes (31) and/or at least one cylindrical portion (38) of the oil holes (31) is/are work-hardened.

A method for heat treating a crankshaft for a vehicle propulsion system, or other work piece, includes heating at least a portion of the crankshaft to a gradual temperature profile. The temperature profile has gradually lower temperatures from the surface to the core of the crankshaft. The temperature profile includes a midpoint temperature at a midpoint between the surface and an innermost part of the core, the midpoint temperature being at least 50% of the surface temperature as measured in the Celsius scale. The surface temperature is within a transformation range of the crankshaft material. The method further includes quenching the surface of the crankshaft journal. The material of the crankshaft is preferably a carbon steel alloy having a DI less than 1.7 and having greater than 0.3 wt % carbon.

A method for heat treating a crankshaft for a vehicle propulsion system, or other work piece, includes heating at least a portion of the crankshaft to a gradual temperature profile. The temperature profile has gradually lower temperatures from the surface to the core of the crankshaft. The temperature profile includes a midpoint temperature at a midpoint between the surface and an innermost part of the core, the midpoint temperature being at least 50% of the surface temperature as measured in the Celsius scale. The surface temperature is within a transformation range of the crankshaft material. The method further includes quenching the surface of the crankshaft journal. The material of the crankshaft is preferably a carbon steel alloy having a DI less than 1.7 and having greater than 0.3 wt % carbon.

A sliding camshaft and a method of manufacturing a lobe pack for a sliding camshaft are provided. The lobe pack is formed from a steel alloy having a carbon content in the range of 0.48-0.53 wt %. The lobe pack is heated to a predetermined austenitizing temperature that is below a carburizing temperature of the steel alloy for a time period at least long enough to heat the entire lobe pack to the predetermined austenitizing temperature. The lobe pack is quenched to a martempering temperature that is greater than a martensite start temperature and within 50 degrees Celsius of the martensite start temperature. The lobe pack is held at the martempering temperature for a martempering time period that is long enough to cool the entire lobe pack to the martempering temperature. The lobe pack may have a hardness in the range of 56 to 60 HRC throughout the lobe pack.

A sliding camshaft and a method of manufacturing a lobe pack for a sliding camshaft are provided. The lobe pack is formed from a steel alloy having a carbon content in the range of 0.48-0.53 wt %. The lobe pack is heated to a predetermined austenitizing temperature that is below a carburizing temperature of the steel alloy for a time period at least long enough to heat the entire lobe pack to the predetermined austenitizing temperature. The lobe pack is quenched to a martempering temperature that is greater than a martensite start temperature and within 50 degrees Celsius of the martensite start temperature. The lobe pack is held at the martempering temperature for a martempering time period that is long enough to cool the entire lobe pack to the martempering temperature. The lobe pack may have a hardness in the range of 56 to 60 HRC throughout the lobe pack.

A method of manufacturing a cam piece for a continuously variable valve duration and a cam piece manufactured therefrom, and more particularly, to material and heat treatment conditions of a cam piece, may include manufacturing a cam piece by casting; heating the cam piece; maintaining a heating temperature; and salt-bathing the cam piece, in which the cam piece includes 3.2 to 4.2 wt % of carbon (C), 2.2 to 3.4 wt % of silicon (Si), and the balance iron (Fe), and may have a carbon equivalent value of 4.4 to 4.6.

A method of manufacturing a cam piece for a continuously variable valve duration and a cam piece manufactured therefrom, and more particularly, to material and heat treatment conditions of a cam piece, may include manufacturing a cam piece by casting; heating the cam piece; maintaining a heating temperature; and salt-bathing the cam piece, in which the cam piece includes 3.2 to 4.2 wt % of carbon (C), 2.2 to 3.4 wt % of silicon (Si), and the balance iron (Fe), and may have a carbon equivalent value of 4.4 to 4.6.

A method of laser hardening a surface area of a workpiece, such as a surface of a journal of a crankshaft, includes the step of: generating a relative movement between the surface of the workpiece and a laser source to allow a laser spot to subsequently be projected onto different portions of said surface area. The method also includes the step of repetitively scanning the laser beam so as to produce a two-dimensional equivalent effective laser spot on said surface area, during the relative movement. The scanning pattern can include at least three substantially parallel lines which the laser spot follows in a certain order. When the workpiece includes several journals having different widths, two laser sources may be used to harden the surface area of the wider journals.