Problems occurred after the installation of Compressed Natural Gas (CNG) using equipment with Diesel Dual Fuel (DDF) in diesel-engine vehicles

Abstract

The purpose of this research is to study the problems occurred after the installation of Compressed Natural Gas using equipment. The research was done in three aspects: installation, practical use, and services. The subject in this study included 939 owners of CNG using trucks in Bangkok and 273 out of them were conducted as a sample group. The research tool included questionnaire to collect data analyzed by SPSS program to find percentage, mean, standard deviation, ANOVA, and Paired Scheffe with the statistic value using the computer application. The result revealed that most of the trucks in this study were Hino with 5,000 cc engine and were used more than 4 years before the installation. After the installation, these trucks had been modified for 3-4 times. After the installation, the engine performance was lower and the changing of motor oils, oil filters and air filters was done earlier before. After the installation, occurred problems were at average level in overall. When considering each aspect, all problems were at average level. When considering each sub-aspect, most problems were at average level. Only taking longer time in gas-filling was at very high level. In overall comparison, when considering each aspect, there was no significant difference among different brand vehicles with the equipment installation. When considering each sub-aspect, there were two types of problems : the installation and practical use. The equipment installation of Toyota was more difficult than Isuzu, Mitsubishi, and Hino. In sub-problems there were different 8 aspects; 1) less consumption in the space of CNG tank installation, 2) less space in engine room, 3) gas leakage, 4) the engine did not run smoothly, 5) it was morevdifficult for maintenance, 6) the gas using equipment was in a shorter age and needs to be often changed, 7) it was unsafe while driving, and 8) it took longer time in gas filling. The problems with Isuzu were found more than Toyota, Hino, and Mitsubishi. In overall, there was no difference in the period of time before the installation. However, when considering each aspect, only practical use was different. When considering each sub-aspect, three differences were found, i.e. the engine did not run smoothly, it was difficult for maintenance, and was unsafe while driving. The problems about the period of time were found after installation, i.e. the vehicles with the under one- year age got more problems than those with 1 to 2-years age , those with 2 to 3-years age , those with 3 to 4-years age and those above 4- years age.