Gaseous fuels: past experiences and future expectations

During the fifties, the use of LPG (Liquefied Petroleum Gas) was promoted in Italy and the Netherlands. The Dutch government promulgated tax regulations which made the use of LPG, available in large quentities as a by-product in the refineries, attractive as an automotive fuel. Dedicated heavy-duty vehicles, mainly city buses, have been used for some time now. The largest fleet of (LPG) city buses have been running in Vienna for a number of years. New interesting developments are being carried out at the moment, as promising markets are developing. Today's engine development is heavily controled by increasingly stringent emission legislation, leading to more rapid developments. The EEV (Enhanced Environmentally Friendly Vehicles)-standards will come into force for polluted areas/cities, creating an extra incentive for the development of extra clean vehicle technology. The future of gaseous fuels depends on the maximum of polluting emission allowed, the technology available and the cost of the concepts developed. Promising developments take place in the area of the conventional prime mover, the diesel engine. Demonstration projects of Exhaust Gas Recirculation (EGR), deNOx-catalysts and particulate traps on diesel engines produce good results. At the end of the day the concept that fulfils all legislative requirements and can be sold at the lowest price will be the winner. And that may be an engine running on a conventional or on an alternative fuel.