Expanded Use of Small Engines by the Application of Butane Fuel Canisters 2010-32-0055

To enhance the convenience of small engines and their current range of application, we studied on the application of commercial liquefied butane fuel canisters containing sealed liquefied normal-butane (n-butane) and iso-butane (i-butane).

In processes for extracting a fuel mixture of n-butane and i-butane in a vapor phase state, the discharge pressure dropped as the fuel within the canister was decreased, due to the phenomenon of prior discharge of the higher vapor pressure of i-butane. This pressure loss from gas discharge had to be restored by raising canister temperature which increased the butane vapor pressure. However, in the liquid phase process, since there is no pressure loss as a vapor, the canister holding temperature could be set lower than that of the vapor phase process. Moreover, when the ambient temperatures were the same or lower than the canister holding temperature, the liquid phase process was superior in terms of heat balance. However, there was superior heat balance in the vapor phase process at ambient temperatures exceeding the canister holding temperature.

In the liquid phase process, the fuel supply system contained residual non-volatile components. These nonvolatile components could however be separated out and removed by utilizing a trap structure in the fuel supply system.

A performance comparison using a 49.4 cm₃ test engine adapted for butane canisters was carried out. Compared to gasoline, engine output was 93%, energy efficiency and THC+NO_X emissions were equivalent, and CO₂ emission was reduced by 11%.

From these results, applying liquefied butane canisters to various products is shown to be an effective means to enhance the convenience of small engines and expand their potential use.