Study On The Power System Matching Scheme For Liquified Natural Gas Bus

There is an important method to solve the problem of urban energy supply andenvironmental problems. It is to develop the alternative fuel vehicles as therepresentative of gas fuel, ethanol fuel, bio-fuels, and to achieve the diversification ofmotor fuels. Natural gas has the characteristics of rich resources, small contamination,high octane and low-cost. It has become an important species of automotive fuels in the21st century. The conditions of using natural gas as automotive fuel in China are ripe. Inrecent years, natural gas vehicle technologies have developed rapidly in China,including compressed natural gas vehicles and liquefied natural gas vehicles.Currently, compressed natural gas vehicles and liquefied natural gas vehicles weremodified products. The modification was based on mostly mass-produced mature dieselvehicles with natural gas engines and fuel systems replaced. The power systemcomponents often remained the same. Thereby, the vehicle performance, especially fueleconomy, would change. Some proper optimizations were needed.The study started with analysing the characteristics of natural gas as motor fuel, andthen the study was going on with the structure of the engine and engine performancecharacteristics of closed-loop power controling, single fuel kind, injection liquefiednatural gas with single point and the difference with diesel engines. These impacts onvehicle performance should be analyzed to improve the necessity of optimizing thepowertrain of LNG buses. Combined with the actual operation of Qingdao buses, theoperating parameters of buses from two typical routes at different time were collectedand analyzed on the basis of automotive theory. The characteristics of the operatingconditions were grasped. The dynamic property of liquefied natural gas buses,economic indicators and the calculation method were determined. Analog computationswere preceded.The property of power and economy of a series of liquefied natural gas buses wereanalyzed in the city. The results were compared with its prototype diesel vehicles. Incity cycle conditions, the differences of fuel consumption of one hundred kilometers showed that powertrain matching parameters of liquefied natural gas buses were neededto be adjusted. More conditions would operate in the engine fuel economy area toimprove the vehicle fuel economy. This study proposed an optimized program. It has acertain significance to guide the development of liquefied natural gas buses. The studycollected the operating records of30liquefied natural gas buses in nine months. Thestudy not only obtained the related evaluation, but also found a number of weak links.On this basis, corresponding improvement measures were proposed.