Air-pollution preventive system

Claim 2

An air-pollution preventive system for an internal combustion engine of a motor vehicle, said engine having a crankcase, a carburetor and a fuel tank having a filler pipe extending into a filler vessel which is formed in an external surface of said vehicle and which is covered by a movable closure member, an air escape pipe communicating with said filler pipe at a short distance from the filler opening of said filler pipe and projecting into said fuel tank a short distance below the top surface of said fuel tank and a fuel vapor passage extending outward from the top surface of said fuel tank, said system comprising a valve means having a valve body mounted on a wall which defines said filler vessel and having therein a chamber, a first port opening into said chamber and communicating with said fuel vapor passage of said fuel tank and a second port opening into said chamber and communicating with said engine, a valve member controlling communication between said first and second ports and projecting into said filler vessel, and a spring biasing said valve member toward a position to obstruct communication between said first and second ports, said valve member being held by said closure member against the action of said spring in a position to provide communication between said first and second ports when said closure member covers said filler vessel, said valve member being held by the action of said spring in a position to obstruct communication between said first and second ports when said closure member is opened during replenishment of said fuel tank thereby preventing said fuel tank from being filled by fuel to its full capacity.

Claim 3

An air-pollution preventive system aCcording to claim 1, further comprising means defining a fuel vapor chamber communicating with said second port of said valve means, said means having therein a ventilation air inlet communicating with the atmosphere and opening into said fuel vapor chamber and a fuel vapor inlet communicating with said crankcase and opening into said fuel vapor chamber, a ventilation air check valve mounted in said ventilation air inlet, a fuel vapor check valve mounted in said fuel vapor inlet, a blow-by gas mixture conduit communicating said crankcase with said carburetor, and a blowby gas mixture check valve controlling communication between said crankcase and said carburetor, said ventilation air check valve being responsive to differences between pressures in the inside and the outside of said fuel vapor chamber between which said ventilation air check valve is put to introduce ventilation air into said fuel vapor chamber and to prevent fuel vapors entered in said fuel vapor chamber from escaping to the atmosphere, said fuel vapor check valve being responsive to differences between pressures in said crankcase and said fuel vapor chamber to introduce ventilation air and fuel vapors entered said fuel vapor chamber into said crankcase and to prevent blow-by gas mixture existing in said crankcase from escaping to said fuel vapor chamber, said blow-by gas mixture check valve being responsive to differences between pressures on the crankcase side and the carburetor side of said blow-by gas mixture check valve to introduce blow-by gas mixture, ventilation air and fuel vapors existing in said crankcase into said carburetor and to prevent said blow-by gas mixture and said fuel vapors introduced into said carburetor from returning to said crankcase.

Claim 4

An air-pollution preventive system according to claim 1, in which said valve member comprising a valve head movably accommodated in said chamber and controlling communication between said first and second ports, a valve stem securely fixed at an end thereof to said valve head and projecting into said filler vessel through said valve body, and a resilient member secured to the other end of said valve stem, said closure member having a projecting member which is securely mounted on the inside surface thereof and which engages said resilient member of said valve stem when said closure member is closed thereby biasing said valve member into said position to provide communication between said first and second ports.

Claim 5

An air-pollution preventive system according to claim 3, in which said valve member further comprises a circular stop secured to a portion of said valve stem which projects in said filler vessel, said spring engaging at an end thereof with said circular stop and engaging at the other end with said valve body thereby biasing said valve member toward said position to obstruct communication between said first and second ports.

Claim 6

An air-pollution preventive system according to claim 4, in which said valve means further comprises a bellow-like cover made of resilient material and enclosing said spring.