^1*2Research scholar Dept of Automobile Engg MIT Campus Anna University Chennai India

³Assistant Professor Dept of Automobile Engg MIT Campus Anna University Chennai India

⁴Associate Professor Dept of Automobile Engg MIT Campus Anna University Chennai India

Email:-ruggers955@yahoo.co.in

Increased environmental awareness and depletion of fossil petroleum resources are driving industry to develop alternative fuels that are environmentally more acceptable. Transesterified vegetable oil derivatives called `biodiesel' appear to be the most convenient way of utilizing bio-origin vegetable oils as substitute fuels in diesel engines. In this project esterified Nerium oil is used as an alternate fuel and the experiments were conducted at three different compression ratio (16:1,14.5:1,13:1) for studying the effect of compression ratio on performance ,emissions, noise and combustion characteristics of diesel engine with using N20 blend(20% nerium oil and 80% diesel) and N40 blend(40% nerium oil and 60% diesel) and diesel alone for comparison. It is observed from the results BTE at higher loads marginally high to that with pure diesel for compression ratio 13:1.SFC, TFC and NOISE tends to decrease with decrease of compression ratio for entire load range. HC and NOx have been reduced drastically at 14.5:1 compression ratio and CO and CO₂ has been reduced drastically at 13:1 compression ratio. Combustion characteristics have been increased by using N20 at 14.5:1 & N40 at 13:1 compression ratios. Hence bio-fuels of nerium oil can replace diesel without compromise in engine performance.