Research Journal of Chemistry and Environment________________________________Vol. 24 (Special Issue I), (2020) Res. J. Chem. Environ. Special Issue on Renewable Energy and Sustainable Environment 44 Characterisation of Diethyl ether Blended Waste Plastic Oil used as a Fuel in Variable Compression Ratio Engine – An Experimental Study Budda Govinda Rao*, Yellapragada Datta Bharadwaz and Pittala Sai Radha Krishna Department of Mechanical Engineering, Gayatri Vidya Parishad College of Engineering (A), Visakhapatnam, INDIA *govind_budda@rediffmail.com Abstract This study is aimed at investigating the effect of compression ratio on the performance and emission characteristics of a single cylinder four stroke variable compression ratio engine fuelled with diethyl ether blended waste plastic oil. Various proportions of diethyl ether blended waste plastic oil P95DEE5 (95% waste plastic oil and 5%diethyl-ether), P90DEE10 (90% waste plastic oil and 10% diethyl ether) and 100% plastic oil (P100) are used for conducting the performance tests. From the experimental investigation, it is found that Brake thermal efficiency is higher for P90 DEE10 blend with compression ratio 18 at brake power 2.85 kW. Brake specific fuel consumption is lower for P90 DEE10 blend with compression ratio 18 at brake power 2.85 kW.CO emissions are lower for P90 DEE10 blend with compression ratio 18 at brake power 2.85 kW. HC emissions are higher for the P90 DEE10 blend when compared to all the test fuels used. NOx emissions are lowered for P90 DEE10 blend when compared to all test fuels with compression ratio 18 at brake power 2.85 kW. Keywords: Variable Compression Ratio (VCR), Waste Plastic Oil (WPO), Brake Thermal Efficiency (BTE), Brake Specific Fuel Consumption (BSFC), Emissions. Introduction The number of automobiles running on petroleum products has grown to a large extent in this modern world for transportation. The petroleum products are derived from the fossil oil which is a non-renewable source of energy. Using the petroleum products as a source of energy for automobiles increasing its consumption and depleting the fossil fuels and reduces to zero level in the future. So, many experimental studies are going on to run the engine with alternate fuels like biodiesel, vegetable oil, rice bran oil, soya bean oil, water emulsions etc. and to have the same efficiency or higher. The present study deals with waste plastic oil blended with diethyl ethers an alternative fuel for the diesel engines. Devraj et al 1 studied the Performance, Emission and Combustion characteristics of waste plastic pyrolysis oil blended with diethyl ether (DEE) in two different proportions with 5% and 10% used as a fuel in single cylinder water- cooled diesel engine. It was observed that Brake power for DEE is less than that of waste plastic oil but brake thermal efficiency (BTE) for 10% DEE at full load is higher. There is a reduction in emissions of both CO and NOx but there is a slight increase in hydrocarbon emissions. Kaimal and Vijayabalan 2 Carried out the experimental investigation using plastic oil blended with DEE in three different proportions 5%, 10% and 15% as a fuel in high- speed single cylinder direct injection diesel engine. Experiments revealed that plastic oil DEE blends have lowered brake specific energy consumption (BSEC) and there is improvement in brake thermal efficiency (BTE). Overall, 15% blended plastic oil with DEE gives better performance and lower CO emissions with a reduction in smoke by 25% and NOx by 29%. Hariharan et al 3 carried out the experimental investigation on single cylinder four-stroke direct injection diesel engine using Tyre pyrolysis oil (TPO) as main fuel and DEE as an additive by admitting it with intake air at flow rates 65g/h, 130g/h and 170g/h. Experimental results show that TPO- DEE at130g/h shows better performance with high peak pressure than diesel fuel (DF) at full load but ignition delay is longer by 2.8 o crank angle than DF thereby reducing the thermal efficiency by 2.5%. NOx emissions are reduced but there is a slight increase in smoke, HC, carbon emissions than DF. Bridjesh et al 4 carried out the experimental investigation on a single cylinder constant speed four stroke diesel engine using 2-Methoxy ethyl acetate (MEA) and DEE as additives with waste plastic oil-diesel blends. The fuels tested consists of 50% diesel with (a) 50% waste plastic oil, (b) 40% waste plastic oil and 10% MEA(c) 40% waste plastic oil and 10% DEE. The author concluded that BTE has increased for all the test fuels used and it is more for the fuel with MEA as an additive. The emissions of hydrocarbon, carbon monoxide and smoke were decreased for the MEA and DEE additives. BSFC has increased for additively added test fuels. Sezer 5 studied the thermodynamic, performance and emission characteristics of a diesel engine using dimethyl ether (DME) and diethyl ether (DEE) as test fuels. These test fuels showed lower pressure and temperature in cylinder than diesel due to this there is an increase in the specific fuel consumption for the same injection rate. Test fuels showed declination in brake power by 32.1% and 19.4% respectively for DME and DEE respectively and increase in brake specific