CNG BUSES FOR CLEAN AND ECONOMICAL CITY TRANSPORT

Abstract

Global warming, increasing air pollution and diminishing oil reserves have made the need for alternative fuel use imperative around the world. Use of compressed natural gas as an alternative fuel is an effective, currently available way to help solve pressing environmental and fuel-resource problems. Because of its lower carbon content (H/C ratio close to 4), natural gas causes about 25% less CO2-emissions than diesel fuel for same amount of energy and thus makes an important contribution to the reduction of CO2 and pollutants. At the MAZ Serbia bus plant in Kragujevac, series production of low-floor urban line-service buses began in mid-2009. The gaseous emissions of the used engine Cummins ISL G, based on the proven Cummins ISL six-cylinder diesel engine, redeveloped for natural gas combustion and fitted with Three-Way Catalyst after treatment with lambda control are more than fifty per cent lower than the EU exhaust emissions limits which apply as of 1st October 2008 (Euro 5). This engine technology can as well be used with biogas-methane. This paper presents the technical characteristics of urban buses MAZ/BIK powered on compressed natural gas, as well as environmental and economic benefits of the introduction of these vehicles in local public transport, primarily in conditions of exploitation in the larger towns. In first time, according to our project "KRAGUJ", diesel buses in urban traffic in the city of Kragujevac, will very quickly be replaced with new CNG powered buses. The future is dedicated to biogas buses, in an effort to reduce emissions of CO2, particles and noise.