HEAVY DUTY LIQUIFIED NATURAL GAS ENGINE DEVELOPMENTS TO MEET FUTURE EMISSIONS REQUIREMENTS. METHODOLOGY AND REAL APPLICATION

摘要

European truck market is close to 100% composed by Diesel vehicles. Their efficiency regarding fuel consumption and mainly its lower fuel cost are the main reasons why they are the selected choice by fleet operators. Just some fleet operators, basically public transport services, are making use of natural gas vehicles due to its lower emissions levels. There were natural engines like Mercedes Benz Econic or Iveco Cursor 8 which were achieving EEV emission standards some years ago while diesel engines where achiving Euro IV limits. Natural gas vehicles, mainly buses and garbage collection trucks, are used inside the cities and always in specific courses where climbing profiles are known. Available market engines operating with natural gas are limited for long distance trucks due to their low power and torque capabilities (mainly due to their low capacities - 6 to 8 liters). Main concerns about OEM natural gas vehicles are range capabilities and maintenance costs. For retrofitted NG vehicles kit cost is also a disadvantage. They are almost all designed to operate with CNG cylinders working at high pressure and doesn't provide enough range to operate as coaches or long distance transports. High weight of this CNG tanks is also a problem. A possible solution for operating range would be installing fuelling stations across main highways in a determined country but the problem would be still there. In Unites States there is an increasing interest about long distance trucks making use of LNG tanks. Legislation is more flexible and permits using LNG tanks in trucks, thus providing a bigger range (around 750 km) to the fleet operators. This would perfectly suit with a long distance transport inside a European country, for example Spain (Barcelona - Madrid: 680 km) or within countries with LNG available at their fuel stations (Barcelona - Lyon: 640 km). It is clear LNG tanks could provide an alternative to private fleets with big trucks but there would be also another problem, the main one: There are no alternative to heavy duty diesel trucks in Europe except for those fleet operators who are interested in retrofitting their trucks. Based on a demonstration project, partially funded by the Spanish Ministry of Industry, Applus+ IDIADA has explored the main technologic limits that apply to existing diesel engines used today in long distance transport and has converted to Natural Gas an European representative truck: the IVECO Stralis, fitter with a 13 liter, 480 HP Cursor 13 engine. In Spain, 2009 heavy duty truck sales where just one third compared to 2008(1), 8235 trucks where sold and Iveco share was 19,4% for a total of 5194 trucks.