Jinan Bus Gas Vehicle Transformation And Applied Research

Compressed natural gas (CNG) has been used as a fuel for internal combustion engines for decades. Developing CNG engine which can meet more strict emission regulations and can improve the oil security of China becomes more and more important. JiNan public transport company has studied CNG engines for several years. This paper mainly introduces the revamping technology of the diesel/CNG engines and the single fuel CNG engines based on the disadvantages of the bi-fuel engine.At first, this paper introduces the revamping technology of the diesel/CNG engines. For most dual-fuel engines can't control the oil quantity well at low speed, this paper designs an oil limiter. This limiter can control the injection quantity accurately according to the operating principle of the speed controller. In order to mix the CNG fuel homogeneously, this paper designs one CNG mix unit. This unit is composed by a mixer, a mixer plate, a CNG controlling valve and a by-pass valve. In order to adjust different conditions, the buses should operate on different combustion modes. Thus this paper revamps the control system which concludes the lever linkage, the air compression system and the electric control system. This control system operates simply performances well. After revamping, this paper tested the engine's dynamic, exhaust and economy performances. The result shows that the dynamic performance was increased and the exhaust was decreased unambiguously. The economy performance was equal or a lit higher than the prototype engine. Based on the good performances of the revamping engine, the public transport company popularized this type diesel/CNG engine.Secondly, this paper introduced the revamping technology of the CJ6922 and the JK6800 buses to single fuel CNG engine. In the revamping process, the crisis technology is matching proper engines to the buses. This paper first selects several engines to match the buses and tested these engines' performances. By comparing these engines' dynamic, exhaust and economy performances, this paper determined the best engines to the CJ6922 and the JK6800 buses. By comparing the performances between the single fuel CNG engines and the diesel/CNG engines, the single fuel CNG engines will develop well in the future.Thirdly, the author defines the safety norms according to his abundant experiences. The safety norms improve the operating safety in a degree..At last, the author summarizes the faults that appear in the operations. Also this paper summarizes the solutions that can increase the efficiency of the maintenance.