Patent ID: 8037809
Filing Date: 2011-10-18
Classification: F04B

Abstract:
1. A piston-and-cylinder assembly comprising a piston displaceably positioned inside a cylinder, the cylinder having a compression chamber, the piston moving between an upper dead point (UDP) and a lower dead point (LDP), a diametral clearance (F) separating a piston slide surface and a cylinder guide surface, the cylinder guide surface being configured so that the diametral clearance (F) will be variable along the displacement of the piston, the diametral clearance (F) being variable from the lower dead point (LDP) to the upper dead point (UDP), wherein the cylinder slide surface has a first displacement stretch positioned close to the upper dead point (UDP) and a second displacement stretch, the second displacement stretch having a truncated-cone profile, a diameter of the truncated-cone profile being relatively larger at a location relatively closer to the lower dead point (LDP) and being relatively smaller at a location relatively closer to the upper dead point (UDP).