MULTI-FUEL ENGINE CONTROL WITH CANISTER PURGE

摘要

A fuel control for a vehicle engine using a liquid mixture of two fuels includes a fuel vapor canister open to the fuel tank and canister purge apparatus effective to allow fuel vapors to be drawn from the canister to the engine at a controlled purge rate during engine operation. The canister purge apparatus is responsive to a fuel composition sensor to vary the purge rate as a function of the fuel composition. If the two fuels are gasoline and methanol, the canister purge rate is varied, in a predetermined range of fuel temperature, so as to provide a higher purge rate for mixtures of gasoline and methanol, in at least some proportions, than for either gasoline or methanol alone. The canister purge rate may further be varied in response to fuel temperature.