A steel piston with an engineered coating is provided. A high thermal conductivity material, for example copper, is disposed on first regions of a combustion bowl to reduce hot spots in the piston. A low thermal conductivity material, for example a ceramic, is disposed on second regions of the combustion bowl to reduce loss of heat through the piston. The high thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 5 μm to help reflect IR radiation and promote fuel flow. The low thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 3 μm to promote fuel flow. The low thermal conductivity material is also disposed on the bowl rim and top ring land, and has a surface roughness (R.sub.a) of greater than 8 μm on the bowl rim and top ring land to retard gas flow.

A steel piston with an engineered coating is provided. A high thermal conductivity material, for example copper, is disposed on first regions of a combustion bowl to reduce hot spots in the piston. A low thermal conductivity material, for example a ceramic, is disposed on second regions of the combustion bowl to reduce loss of heat through the piston. The high thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 5 μm to help reflect IR radiation and promote fuel flow. The low thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 3 μm to promote fuel flow. The low thermal conductivity material is also disposed on the bowl rim and top ring land, and has a surface roughness (R.sub.a) of greater than 8 μm on the bowl rim and top ring land to retard gas flow.

A steel piston (1) for a combustion engine, having an upper part in which a ring section (7) with at least one ring groove (8) is arranged, wherein the upper part is adjoined by a lower part that has two opposing skirt wall sections (2), wherein the two skirt wall sections (2) are connected via two mutually opposite case walls (3), wherein a pin bore (4) surrounded by a piston boss (6) is provided in each case wall (3). In one example, there is at least one aperture (14) or at least one recess in the case wall (3) in the region between the piston boss (6) and the skirt wall section (2).

The present invention relates to pistons (10) for use in internal combustion engines, having: a piston crown (12) which is adjoined by a piston skirt (14), wherein the piston skirt (14) has surfaces (18) which abut the cylinder wall during use of the piston, wherein the surfaces (16) have one or more friction-reducing coatings (18) and wherein depressions (20) are provided in the coating, which are arranged such that the spacing S between each two adjacent depressions (20) along the axial direction (A) of the piston and the width L of the depressions (20) along the axial direction (A) of the piston satisfy the formula S>2L.

The present invention relates to pistons (10) for use in internal combustion engines, having: a piston crown (12) which is adjoined by a piston skirt (14), wherein the piston skirt (14) has surfaces (18) which abut the cylinder wall during use of the piston, wherein the surfaces (16) have one or more friction-reducing coatings (18) and wherein depressions (20) are provided in the coating, which are arranged such that the spacing S between each two adjacent depressions (20) along the axial direction (A) of the piston and the width L of the depressions (20) along the axial direction (A) of the piston satisfy the formula S>2L.

The present disclosure provides piston, comprising: a skirt having an upper body portion; a crown formed at the upper body portion; and a piston bowl formed at the crown. The piston bowl includes a first combustion surface and a second combustion surface opposite the first combustion surface. Each of the first combustion surface and the second combustion surface are formed and positioned to accommodate inflowing injector spray so as to reduce heat transfer caused by impingements made by the inflowing injector spray.

The present disclosure provides piston, comprising: a skirt having an upper body portion; a crown formed at the upper body portion; and a piston bowl formed at the crown. The piston bowl includes a first combustion surface and a second combustion surface opposite the first combustion surface. Each of the first combustion surface and the second combustion surface are formed and positioned to accommodate inflowing injector spray so as to reduce heat transfer caused by impingements made by the inflowing injector spray.

A sprayed coating for a sliding member of the present invention includes a ferrous alloy containing chromium (Cr). The sprayed coating for the sliding member has the content rate of the chromium of 8 mass % or more, includes a structure that comprises crystal grains contained in the sprayed coating and having an average grain size of 3 μm or less, has a Vickers hardness of 300 Hv or more, and then is excellent at abrasion resistance.

A sprayed coating for a sliding member of the present invention includes a ferrous alloy containing chromium (Cr). The sprayed coating for the sliding member has the content rate of the chromium of 8 mass % or more, includes a structure that comprises crystal grains contained in the sprayed coating and having an average grain size of 3 μm or less, has a Vickers hardness of 300 Hv or more, and then is excellent at abrasion resistance.

A coating composition for forming a coating film including particles and a resin binder is so configured that a content of the particles in the coating film is more than 30 vol%, the coating composition includes the particles, a raw resin of the resin binder, and a solvent, and a ratio V/D is 2.5 or less, where V is a volatilization rate (g/m.sup.2.Math.s) of the solvent, and D is a diffusion coefficient (10.sup.−9 m.sup.2/s) of the solvent in the coating composition.