http://www.iaeme.com/IJMET/index.asp 123 editor@iaeme.com International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 3, March 2017, pp. 123–130 Article ID: IJMET_08_03_014 Available online at http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=3 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed COMPARATIVE EMISSION ANALYSIS OF CNG AND OCTANE IN RETROFITTED CAR ENGINES Zawad Abedin, Mousumi Rizia and H M Khairul Enam Department of Mechanical Engineering, Military Institute of Science and Technology, Mirpur Cantonment, Dhaka 1216, Bangladesh ABSTRACT Comparative emission analysis of octane and compressed natural gas (CNG) fueled retrofitted spark ignition car engine refers to exhaust emission (carbon mono- oxide, carbon di-oxide, Nitrogen Oxide) analysis and exhaust temperature on car engines which are operated with either gasoline or CNG using a solenoid actuated valve mechanism. The analysis was successfully carried out with the help of an exhaust gas analyzer (IMR 4000). Octane was used as the conventional fuels, whereas CNG was the alternative fuel. Comparative analysis of the experimental results showed the retrofitted engine produced higher exhaust gas temperature and NOx emission over different engines of different mileage when were used with CNG. Other emission contents were significantly lower than those of the gasoline emissions. Key words: Exhaust temperature, NO x , Knocking, CNG (Compressed Natural Gas). Cite this Article: Zawad Abedin, Mousumi Rizia and H M Khairul Enam, Comparative Emission Analysis of CNG And Octane in Retrofitted Car Engines. International Journal of Mechanical Engineering and Technology, 8(3), 2017, pp. 123–130. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=3 1. INTRODUCTION Over the last few decades it has been observed that the number of automotive vehicles is increasing at a very high rate in most big cities globally. Around the world it is acknowledged that an alternative fuel to gasoline needed to be developed. Alternative fuels need to be used more for automobile use for their obvious emissions benefits, but also as a tool for a country to become less dependent on the oil imported. Although natural gas is a hugely available resource in some countries, it has not been widely accepted as an alternative fuel to gasoline. Although in some countries, it is extensively used as alternate fuel due to its lower price and availability. Hence, research has to be done to decide whether this is detrimental to the environment or we can count on CNG as alternative fuel. In this analysis, general exhaust gas analyzer is used which operates with the sampling system shown in Figure 01.