Patent ID: 8695951
Filing Date: 2014-04-15
Classification: F02D,F02M

Abstract:
1. A carburettor including a primary air passage ( 19 ) having an upstream inlet ( 6 ) and a downstream outlet ( 11 ), an adjustable throttle valve ( 8 ) situated within the primary air passage, a fuel supply nozzle ( 28 ) communicating with the primary air passage and connected to a fuel metering valve ( 23 ) for varying the amount of fuel discharged through the fuel supply nozzle, said fuel metering valve comprising a bore defining member ( 32 ) movably accommodating a valve member ( 33 ), the bore defining member and the valve member defining a fuel inlet space ( 35 ), a fuel inlet ( 37 ) communicating with the fuel inlet space, a fuel outlet ( 39 ) passing through a wall of the bore defining member ( 32 ) and communicating with the fuel supply nozzle ( 28 ), and a portion of an outer surface of the valve member ( 33 ) being so profiled that the valve member is movable relative to the bore defining member ( 32 ) such that an area of communication between the fuel inlet space ( 35 ) and the fuel outlet ( 39 ) varies progressively between a maximum and a minimum value, characterised by a secondary air passage ( 13 ) with a secondary inlet ( 10 ) and with an outlet ( 24 ) to the primary air passage ( 19 ) between the adjustable throttle valve ( 8 ) and the primary air passage downstream outlet ( 11 ), the fuel outlet ( 39 ) of the fuel metering valve ( 23 ) communicating with the secondary air passage ( 13 ), the fuel supply nozzle ( 28 ) communicating with the secondary ( 13 ) and primary ( 19 ) air passages such that the fuel is arranged to mix with the air flowing through the secondary air passage ( 13 ) before flowing through the fuel supply nozzle ( 28 ) and mixing with the air flowing in the primary air passage ( 19 ) downstream of the adjustable throttle valve ( 8 ).