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Following general considerations on the present state of commuter traffic in the downtown sections of the cities, the specifications of an highly efficacious and efficient vehicle for individual transportation are analyzed. A two-wheeler vehicle appears very attractive when pollution and noise are overcome. A new formula of vehicle is so presented looking for a minimum optimun solution to the problem. The basic feature consists in an hybrid propulsion system, namely: internal combustion engine with catalytic muffler for downtown approach and an accumulator powered electric motor during restricted area trips. After the presentation of the experimental results, some considerations on utilization coefficient as well as energy use efficiency, in comparison with other modes of transportation, are presented.

The advantages of air assisted direct fuel injection systems to achieve high atomization degree into the combustion chamber of SI engines are well-known. The solutions up to now proposed appear anyway poorly tailored to be suitable for small engine applications. In fact scaling down such existing systems for automotive applications, they present mainly two drawbacks: the costs and a difficult tuning of the very low quantity of fuel required per cycle. Moreover the amount of electric energy required makes the engines not self-sufficient. To overcome the above mentioned problems, Piaggio has developed a completely mechanical low cost fuel injection system, named FAST (Fully Atomized Stratified Turbulence), which does consent a very atomized and stratified mixture lean combustion process, i.e. a dramatic improvement of emissions and fuel consumption. After general considerations, the application of such system to a small capacity 2T engine is analyzed.

"In the design of new CI engines, it is of paramount importance to reduce the pollutants and fuel consumption," writes author Marco Nuti. In this, the first book devoted entirely to exhaust emissions from two-stroke engines, Nuti examines the technical design issues that will determine how long the two-stroke engine survives into the twenty-first century. Dr. Nuti, director of Technical Innovation at Piaggio, thoroughly explores pollutant formation and control from unburned hydrocarbon emissions, carbon monoxide emissions, catalytic aftertreatment, and secondary air addition.