International Journal of Modern Engineering Research (IJMER) www.ijmer.com Vol.1, Issue1, pp-210-224 ISSN: 2249-6645 210 | P a g e Chennakesava Reddy 1 , M.V.S. Murali Krishna 2 *, P.V.K.Murthy 3 and T. Ratna Reddy 4 1 Department of Mechatronics, Mahatma Gandhi Institute of Technology, Gandipet, Hyderabad – 500 075 2,4 Mechanical Engineering Department, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad-500 075, Andhra Pradesh, India, *E-mail: maddalivs@gmail.com 3 Vivekananda Institute of Science and Information Technology, Shadnagar, Mahabubnagar-509216, Andhra Pradesh, India, . ABSTRACT Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel engine consisting of air gap insulated piston with 3- mm air gap, with superni 2/4(an alloy of nickel) crown and air gap insulated liner with superni insert with different operating conditions of crude pongamia oil (CPO) with varied injection pressure and injection timing. Performance parameters of are determined at various magnitudes of brake mean effective pressure. Pollution levels of smoke and oxides of nitrogen (NOx) are recorded at the peak load operation of the engine. Combustion characteristics at peak load operation of the engine are measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with CPO operation at recommended injection timing and pressure and the performance of both version of the engine is improved with advanced injection timing and at higher injection pressure when compared with CE with pure diesel operation. Peak brake thermal efficiency increased by 5%, smoke levels decreased by 4% and NOx levels increased by 40% with CPO operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing. Keywords: Crude pongamia oil, LHR engine, Performance, Pollution levels, Combustion characteristics. 1.INTRODUCTION In the scenario of increase of vehicle population at an alarming rate due to advancement of civilization, use of diesel fuel in not only transport sector but also in agriculture sector leading to fast depletion of diesel fuels and increase of pollution levels with these fuels, the search for alternate fuels on has become pertinent for the engine manufacturers, users and researchers involved in the combustion research. It is well known fact that about 30% of the energy supplied is lost through the coolant and the 30% is wasted through friction and other losses, thus leaving only 30% of energy utilization for useful purposes. In view of the above, the major thrust in engine research during the last one or two decades has been on development of LHR engines. Several methods adopted for achieving LHR to the coolant are i) using ceramic coatings on piston, liner and cylinder head ii) creating air gap in the piston and other components with low-thermal conductivity materials like superni, cast iron and mild steel etc. Through ceramic coatings provided insulation and improved brake specific fuel consumption (BSFC), peeling of coating was reported by various researchers [1-4] after certain hours of duration. Creating an air gap in the piston involved the complications of joining two different metals. Though Parker et al. [5] observed effective insulation provided by an air gap, the bolted design employed by them could not provide complete sealing of air in the air gap. Dhinagar et al. [6] applied different degrees of insulation like ceramic coated cylinder head, air gap insulated piston and air gap insulated liner and conducted experiments with pure diesel operation and reported LHR version of the engine improved the performance. Rama Mohan [7] made a successful attempt of screwing the crown made of low thermal conductivity material, nimonic (an alloy of nickel) to the body of the piston, by keeping a gasket, made of nimonic, in between these two parts. Low degree of insulation provided by these researchers Potential of a Low Heat Rejection Diesel Engine with Crude Pongamia Oil