การศึกษาผลการใช้ก๊าซธรรมชาติระบบเชื้อเพลิงร่วมในเครื่องยนต์ดีเซล / พงศธร บวรสิน = The study of using natural gas in a dual fuel diesel engine / Pongsatorn Borwornsin
The investigation is aimed to compare performance, smoke and durability of dual fuelled engine with diesel engine, and effects of dual fuelled engine’s durability in real usage. The investigation is devided into two parts. First part, using the same model vans, is engine performance comparative test between dual fuelled engine and diesel engine in a control condition. This part was devided into three parts. 1. Performance test on chassis dynamometer with constant speed and steady state conditions, at full load, was found that brake power of van using DDF is not different to van using diesel but some test speeds van using DDF has more brake power than van using diesel about 8.34%. Specific Total Energy Consumption (STEC), exhaust gas temperature and smoke in van using DDF are higher than in van with diesel in full load. At part load, STEC, Exhaust gas temperature of van using DDF are higher than in van using diesel and smoke of van using DDF is not difference from the van using diesel. 2. Constant speed Road test, it was found that STEC, exhaust temperature, diesel consumption trend to be increased as velocity were increased. Energy consumption from van using DDF is higher than van using diesel ranging from 13.42-24.45%. Diesel substitute trends become decreasing as the velocities are increased. 3.Durability test for 40000 kms, by driving one van following the other van, it was found that energy consumption trends of both van are similar. Average consumption from van using DDF and van using diesel is ranging between 4.85 and 4.04 MJ/km. Exhaust smoke from a van using DDF is higher than a van using diesel. The result from lubrication monitoring has shown that lube oil in a van using DDF had higher oxidation and nitration rate than van using diesel, but metal wear contamination was not significantly observed. Second part is about engine’s durability monitoring of dual fuelled engine in real uses for 20000 kms. With a pickup truck, it was found that fuel consumption has constant trend but smoke is slightly higher than an initial condition. The results from lubrication test has shown that lube oil had no abnormal in wear contamination and lube oil properties. For six DDF trailors, we found that energy consumption trends are also constant. Smoke is, however, increased as lube oil working hours are increased. The result from lubrication test has shown that, with longer service hours, oil’s viscosity is decreasing and copper contamination is higher than abnormal due to the degradation of lube oil properties. We can conclude that, with DDF, the higher energy consumption than using diesel the higher in lubrication oil’s thermal load that may caused oil’s degradtion such as lower viscosity, higher oxidation and nitration. However, these are not approached the level that may affect the engine long term usage.
