I've been reading about EMAK-Efco's "burn right" 2 stroke fuel injection technology, it's very ingenious. It's found on their saws with the green "burn right" decal. Here's how it works:
There is a set of small ports above and below the main intake port. These two small ports are connects by a connector tube. There is a one way valve in the upper port valve body (like a reed valve). A fuel accumulation chamber is also in the valve body area. As the piston moves up, it opens the lower port and creates a vacuum in the connector tube (due to one way reed valve) and draws fuel into the accumulator chamber through a special passage in the intake manifold boot. (Main intake port still closed). As the piston reaches TDC and the power stroke starts the cylinder pressure is fed into the upper port and travels down into the connector tube throught the one way valve and bounces off the closed lower port (piston skirt).
The compression wave then travels back up the connector tube and atomizes the fuel in the accumulator chamber very finely and sprays this fuel into the combustion chamber as the regular transfer ports are also charging the cylinder with the fuel air mixture from the carb.
The carb mix is weaker (leaner) than normal, but that is offset by the fuel injection feature.
Due to the fine atomization, better fuel economy and lower emissions result. And the system needs no maintenance and has only 1 moving part. It uses a normal butterfly carb. That's very different from the strato-charging method.
There is a set of small ports above and below the main intake port. These two small ports are connects by a connector tube. There is a one way valve in the upper port valve body (like a reed valve). A fuel accumulation chamber is also in the valve body area. As the piston moves up, it opens the lower port and creates a vacuum in the connector tube (due to one way reed valve) and draws fuel into the accumulator chamber through a special passage in the intake manifold boot. (Main intake port still closed). As the piston reaches TDC and the power stroke starts the cylinder pressure is fed into the upper port and travels down into the connector tube throught the one way valve and bounces off the closed lower port (piston skirt).
The compression wave then travels back up the connector tube and atomizes the fuel in the accumulator chamber very finely and sprays this fuel into the combustion chamber as the regular transfer ports are also charging the cylinder with the fuel air mixture from the carb.
The carb mix is weaker (leaner) than normal, but that is offset by the fuel injection feature.
Due to the fine atomization, better fuel economy and lower emissions result. And the system needs no maintenance and has only 1 moving part. It uses a normal butterfly carb. That's very different from the strato-charging method.
