This article presents a collection of studies relating to the development of technologies using hydrogen with compressed natural gas or Hydrogen-enriched Compressed Natural Gas (HCNG). Regarding to the issues of mixing ratio the data show that the appropriated amount of hydrogen falls between 20%-30% by volume in order to balance any tradeoff between engine performance and emissions. The equivalent ratio can be adjusted to be as low as 0.5-0.6. The ignition timingmust also be retarded (Ignition Delay) by averagely 5 degrees of crankshaft rotation to compensate for the change of burning speed. Theuse of 20%-30% of hydrogen by volume decrease both HC and NOx as compared to the use of CNG alone. In terms of the fuel system design the individually-stored gas injection system is of interest. It provides flexibility especially for the adjustment of the fuel composition for optimum ration in any operating conditions. But at present there is no commercial development of such system.

The research was aimed at studying 1) fuel energy saving of automobile drivers in Nonthaburi province 2) a correlation between cause and effect on fuel energy saving of automobile drivers in Nonthaburi province and 3) a model made for assessing fuel energy saving of automobile drivers in Nonthaburi province. The questionnaires were constructed as a tool for collecting data from 2389 automobile drivers who had been getting their car filled in gas station in Nonthaburi province. The statistics used for analysis were SPSS version 17.0 with frequency distribution percentage arithmetic mean K related samples and path analysis. The research finding indicated that the 98.06 percents of automobile drivers in Nonthaburi province had knowledge about fuel energy saving the 87.99 percents had agreeable attitude towards fuel energy saving and the 80.59 percents had operated fuel energy saving. They all had different levels of knowledge attitude and operation. It showed that the automobile drivers with knowledge and agreeable attitude didnt sometimes put it into operation and they sometimes had disagreeable attitude in spite of having knowledge. The result of hypotheses tests at the statistical significance of 0.05 showed that the types of fuel energy used in the car a change of types of fuel energy used in the car knowledge provided about fuel energy saving in the car knowledge and attitude towards fuel energy saving in the car correlated with fuel energy saving of automobile drivers in Nonthaburi province. Moreover a model made for assessing fuel energy saving of automobile drivers in Nonthaburi province was