Crankcase ventilation

Claim 1

In a crankcase ventilating device for controlling the flow of gases from the crankcase to the fuel-air inlet induction conduit of an internal combustion engine to effect a predetermined low rate of flow when a predetermined large pressure differential exists between said crankcase and conduit corresponding to engine operation approximating idle conditions and to effect an increasing rate of flow when said pressure differential decreases with increasing engine load, the combination of A. a tubular valve housing comprising inner and outer tubular members having a gas passage extending therethrough and opening at upstream and downstream ends respectively adapted for connection with said crankcase and conduit respectively, B. said outer member defining a metering orifice comprising part of said passage, C. said inner member comprising a spring retainer of resilient material having 1. a downstream end telescoped into the upstream end of said outer member, 2. means effective before said inner member is telescoped into said outer member to permit radially outwardly resilient flexing of the downstream end portions of said inner member around the downstream opening defined thereby to expand said downstream opening to receive therethrough resilient means oversize with respect thereto, comprising a plurality of peripherally spaced and axially extending endwise opening slits in said downstream end of said inner member, 3. an enlargement, with respect to its unexpanded downstream opening of its interior passage, at the region of said slits, and 4. a backfire control valve seat defining a second orifice smaller than said unexpanded downstream opening and comprising a part of said passage upstream of said slits, D. valve means in said passage having 1. a downstream metering portion movable in the downstream direction to restrict said metering orifice, and 2. an upstream backfire valvE portion oversize with respect to said second orifice and movable in the upstream direction into seating engagement with said backfire control valve seat to close said passage, E. resilient means within said inner member for yieldingly opposing downstream movement of said valve means having 1. one end seated on said valve means, and 2. a second end oversize with respect to said unexpanded downstream opening of said inner member confined within said enlargement of the interior thereof to maintain a predetermined spatial relationship between said resilient means and inner member for all positions of said valve means.