Asian Journal of Applied Science and Engineering ISSN 2305-915X(p); 2307-9584(e) Asian Business Consortium | AJASE ● Feb 2015 ● Vol 4 ● Issue 10 Page 38 Surface Morphology and Wear Investigation of Valves used in LPG- fueled Passenger Car Engines Ajay Pandey 1 , R. K. Mandloi 2 Department of Mechanical Engineering, MANIT, Bhopal, India ARTICLE INFO ABSTRACT Volume 4 Number 1/2015 Issue 10 DOI Prefix: 10.15590 Received: Feb 02, 2015 Accepted: Feb 10, 2015 Published: Feb 18, 2015 E-mail for correspondence: profajp@gmail.com Liquefied petroleum gas (hereafter LPG), with an Octane Number of ~105, was looked upon and used as a viable vehicle - fuel option as early as 1912. However, its usage gained significant momentum with the advent of dual – fuel technology in the mid 1950s. This technology made it possible for LPG to be used in parallel with another fuel – Gasoline or Diesel. Though the LPG fuel system has become far more sophisticated while moving from 1 st generation of technology development to the 5 th one, most passenger car engines running on LPG are still not specially designed to operate on LPG. It is a very common practice in many developing countries, including India, to use retrofitted gasoline engines that operate on a dual – fuel mode: LPG and petrol. The extreme temperature conditions in LPG - run retrofitted gasoline engines result in considerable changes in the microstructure and wear growth patterns for both inlet and exhaust valves. This investigation focused on analysis of valve wear using a Pin – on – Disc (POD) wear tester. The characterization of wear was done by wear rate, analyses of worn surfaces, wear debris structure and sub – surfaces. The precipitation characteristics and behavior of secondary particles like carbides, oxides, silicates, etc., was also studied. The microstructure analysis and quantitative metallography of inlet and exhaust valve specimens was carried out by employing Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques. The images thus obtained were utilized for microstructural characterization of the valve specimens. The surface morphology of the valve material was studied and AFM measurements were used for quantitative characterization of the structure as also to gain useful information about crystallographic orientation of individual grains, the formation of cracks, identification of potential crack initiation and fracture sites, etc. A comparative evaluation of microstructure of worn - out valves with new valves was also carried out. Keywords: LPG, retrofitting, poppet valve, wear, microstructure Source of Support: Nil, No Conflict of Interest: Declared. How to Cite: Pandey A and Mandloi RK. 2015. Surface Morphology and Wear Investigation of Valves used in LPG- fueled Passenger Car Engines Asian Journal of Applied Science and Engineering, 4, 38-47.