Analysis of EGR Coupled Less Heat Rejection Model of Diesel Engine with Blends of Jatropha Biodiesel, Diesel and Diethyl Ether: An Experimental Approach

The experimental investigation on a less heat rejection model (LHRM) of the diesel engine was done with the objective to improve the performance and emission characteristics. The LHRM has a bond coat of NiCrAl interposed between the thermal barrier ceramic coated cylinder head and liner of the engine. The model is coupled with exhaust gas recirculation (EGR) system at a constant rate of 10 vol.%. The test fuels are neat diesel for the non-coated engine (NCE) and blends with different ratios of diesel-Jatropha biodiesel, keeping a constant ratio of additive diethyl ether (DEE) for the LHRM. The load was varied from 0 to 100 % and injection timing (IT) from 29 degrees to 34 degrees BTDC. The performance parameters of both engines improved significantly with the advancement of the injection timing. The NOx emissions reduced with no effect on BSEC, BTE and smoke levels with 10 % EGR rate. The optimum blend and IT for LHRM are D20JB60A20 by vol. (20 % of diesel +60 % of Jatropha biodiesel +20 % of additive DEE) and 32 degrees BTDC as the maximum enhancement of about 6 to 7 % in peak BTE with a reduction in BSEC by 9.5 %, EGT by 18 %, VE by 2 to 3 %, smoke level by 44.5 % and NOx emissions by 14.2 % were found compared to NCE with diesel at normal operating conditions. At advanced injection timings with a higher load, in comparison to NCE, LHRM showed significant improvement in all of the investigated parameters.