Use of natural gas on heavy duty vehicles in Brazil: experience, current scene and barriers that still persist; Utilizacao do gas natural em veiculos pesados no Brasil: experiencia, cenario atual e barreiras que ainda persistem

In the 80's, because of the oil crisis, the Natural Gas (NG) appeared as a fuel with a great potential for Diesel replacement in Heavy Duty Vehicles. At that time, PETROBRAS with other companies have developed partial conversion technologies from Diesel to NG, known as 'Dual Fuel'. Engine dynamometer and vehicle bus tests have been developed to verify its technical and economical viability. Because of several factors, the Dual Fuel Program did not advance and the experience was interrupted. At the same time, other experiences using NG Otto Cycle bus engines, manufactured in Brazil, have been conducted, mainly at Sao Paulo, nevertheless, without expansion. Currently, factors as increase of the NG converted light vehicles fleet; the NG excess in the National Market, which has contributed to the NG distribution net expansion; the Environmental Legislature in vigor, that continuously determine lower emission limits; the government interest in increasing the NG energy matrix share and in reducing Diesel fuel consumption, and the low NG industrial demand, compose together a great scene to the diffusion of NG as substitute to the Diesel fuel in Heavy Duty Vehicles. (author)