Temperature-responsive system for regulating the fuel mixture in air-cooled internal combustion engines

Claim 1

In a regulating system for controlling the fuel mixture delivered by a fuel injection system to an externally ignited, air-cooled internal combustion engine, said regulating system is of the type that includes (a) an rpm-responsive setting member, (b) a first intermediate lever to which the motions of said rpmresponsive setting member are transmitted, (c) a second intermediate lever connected to said first intermediate lever and to a fuel quantity control member to transmit thereto displacements of said rpm-responsive setting member and (d) a correcting lever to which said second intermediate lever is pivotally secured, the improvement comprising, A. an expandable temperature sensing member constituting an additional setting member and disposed within the cooling circuit of said air-cooled engine to respond to the temperatures of the cooling air, said temperature sensing member having a first end and a second end, B. rod means attached to said first end of said temperature sensing member, said rod means being displaced in a first direction by said temperature sensing member by virtue of its expansion caused by an increase in the temperature of said cooling air, C. first spring means constituting a resilient abutment for said temperature sensing member and being in engagement with said second end thereof, said first spring means opposing the expansion of said temperature sensing member, D. second spring means operatively connected to said rod means for urging the latter in a second direction opposite to said first direction; said second spring means being weaker than said first spring means for allowing said rod means to move in said first direction in response to the expansion of said temperature sensing member, E. a contoured control edge provided on said correcting lever and having 1. a first, steep portion, 2. a second, relatively substantially flatter portion and 3. rigid stop means at the end of said second portion and F. camming means cooperating with said contoured control edge for causing a relatively fast rate of motion of said correcting member and thus a relatively large rate of displacement of said fuel quantity control member while said camming means is in contact with said steep portion and for causing a relatively slow rate of motion of said correcting member and thuS a relatively small rate of displacement of said fuel quantity control member while said camming means is in contact with said flatter portion, said camming means arriving into engagement with said rigid stop means when a certain state of expansion of said temperature sensing member is reached in response to a predetermined temperature; the engagement between said rigid stop means and said camming means preventing further movement of said rod means in said first direction in response to temperatures beyond said predetermined temperature, said first spring means undergoing compression beyond said predetermined temperature for taking up the forces generated by the expansion of said temperature sensing member subsequent to the engagement between said camming means and said rigid stop means.