Improving performance and reducing emissions from a gasoline and liquefied petroleum gas bi-fuel system based on a motorcycle engine fuel injection system

摘要

Motorcycles are popular vehicles in Vietnam, and their numbers are increasing. According to forecasts, there will be about 75 million in circulation by 2025, which is the year Vietnam will start implementing exhaust gas testing for motorcycles by Vietnamese National Standards "TCVN 643:2018". This is the maximum permitted limit of exhaust gases for road vehicles in Vietnam. It is difficult for older motorcycles to meet this requirement, so alternative fuels need to be considered. LPG has the advantage of being a clean fuel in abundant supply, and so has the potential to provide a solution. This study was conducted on an old motorcycle of a type that is very common in Vietnam. A bi-fuel LPG and gasoline system was built from the fuel injection system on the motorcycle, with only the need to calculate, design and install two additional injectors for the LPG. The engine was run on a test platform using GT-POWER simulation software, which optimized the primary ignition angle for the LPG. The performance and pollution data were compared between gasoline and LPG, both by experiment and simulation. The results show that the performance of the LPG declines. However, the exhaust emission and fuel economy improve. The system studied does not require a change to the fuel injection system or the engine, manufacturing costs are low, and it is easy to apply in the actual situation of motorcycles in Vietnam today.