Scavenging air/fuel-air mixture control device for a stratified scavenging two-cycle engine

A scavenging air/fuel-air mixture control device for a stratified scavenging two-cycle engine comprising;

• an air valve for controlling the scavenging air flow rate, provided in an air passage connected to a scavenging passage linking a crankcase and a combustion chamber, the air valve opens and closes the air passage based on the angular reciprocal movements of its valve body;
• an output-controlling throttle valve incorporated in a fuel-air mixture passage provided in a carburetor and connected to the crankcase, the throttle valve opens and closes the fuel-air mixture passage based on the linear reciprocal movements of its valve body;
• and
• an interlocking mechanism for interlocking the valve and the throttle valve and including a flow-rate controlling mechanism for fuel to be sent into the fuel-air mixture passage;
• wherein the interlocking mechanism has a drive member that is secured to the air valve and that rotates based on accelerator operations, a cam provided in the drive member, and a slave member that is secured to the throttle valve and that goes through linear reciprocal movements by following the cam, and opens and closes the air valve and throttle valve in relation to one another in response to accelerator operations;
• and
• wherein the fuel flow-rate controlling mechanism has a metering needle provided in the throttle valve and a metering window provided in a fuel passage leading from a constant fuel chamber to the fuel-air mixture passage, and the flow rate of the fuel to be sent into the fuel-air mixture passage is controlled by having the metering needle vary an opening area of the metering window according to the opening of the throttle valve.