Patent ID: 7217357

Claim:
An oil filter for engines, transmissions or automatic transmissions, said oil filter being integrated in an oil pan and comprising: an oil filter housing having a top shell and a bottom shell and a filter medium positioned therein; and at least one bypass valve arranged within the oil filter housing and comprising (i) a bypass housing, (ii) a bypass opening, (iii) a closing means seated within the bypass valve housing, (iv) a spring biasing the closing means to block said bypass opening, and (v) a bypass housing lid, said bypass housing lid capping said bypass valve housing and consisting of a planar section positioned against an underside of the top shell and an outer peripheral flange surrounding the bypass valve housing, said spring having a spring resistance that increases with increasing temperature, wherein the spring resistance of the spring is a range of 10 N to 120 N when the spring is at temperatures above 30° C., and wherein said spring is made from a shape memory alloy, selected from the group consisting of NiTi, CuZnAl or CuAlNi, said closing means being configured to allow oil to bypass the filter medium when the unfiltered oil pressure overcomes the spring resistance.