火花点燃发动机燃用甲醇汽油混合燃料的研究

A 3-cylinder PFI engine was adopted to study engine power, torque, fuel economy, emissions including regulated and non-regulated pollutants and cold start performance with the fuel of low fraction methanol in gasoline. Without any retrofit of the engine, experiments show that the engine power and torque will decrease with the increase fraction of methanol in the fuel blends under WOT conditions. However, if spark ignition timing is advanced, the engine power and torque can be improved under WOT operating conditions. Engine thermal efficiency is thus improved in almost all operating conditions. Engine combustion analyses show that the fast burning phase becomes shorter, however, the flame development phase is a little delay. When methanol/gasoline fuel blends being used, the engine emissions of CO and HC decrease, NOx changes little prior to three-way catalytic converter (TWC). After TWC, the conversion efficiencies of HC, CO and NOx are better.