Model-Based A/F control for liquid-phase injected SI ICEs

One of the most promising near-future alternatives to traditional gasoline and Diesel Internal Combustion Engines is the utilization of alternative fuels. Among these, Liquefied Petroleum Gases (LPG) play a key role for its wide availability and high energetic density. The adoption of liquid phase injection systems would permit the highest achievable performances from both a traditional (power output, acceleration, …) and an environmental (pollutants and greenhouse emissions) point of view. Those systems, however, still present many unsolved problems, substantially limiting their use. The authors here report the results of an intense research activity aimed to the realization of a modelbased A/F controller to be used on-board for liquidphase LPG injected engines. All the main dynamical phenomena involved were modeled: it was so possible to analyze in detail the efficiency of the system in terms of A/F control (strictly related to