PERFORMANCE AND EMISSION CHARACTERISTICS OF VCR ENGINE WITH CASTOR OIL BIODIESEL

Castor biodiesel was obtained from castor-seed by transesterification process. Castor biodiesel obtained from transesterification process is used to investigate the performance and emission characteristics of single cylinder, four-stroke, multi-fuel, water-cooled, variable compression ratio (VCR) engine. An online emission and performance test was performed at compression ratios 15, 16, 17, and 18 under constant 1,500 rpm by using engine performance analysis software "Engine-soft". Portable AVL gas analyser was used to measure different constituents in exhaust gas such as amounts of carbon monoxide (CO) (vol%) and carbon dioxide (CO2) (vol%), nitrogen oxides (NOX) (ppm), unconsumed oxygen (O-2) (vol%) in the exhaust, as well as amount of unburned hydrocarbons HC (ppm). The engine was run with blending ratio (B00 to B50) and VCR from 15 to 18 at varying loads. It has been inferred that the engine torque increases with the engine load linearly, thus showing no effect of blending and compression ratio on it. However, the mechanical efficiency increases with load non-linearly and B20 (20% blended biodiesel) gives maximum efficiency (52%) at peak load at all compression ratios. The fuel consumption is maximum (1.30 kg/h) at peak load of 10 kg with B50 at CR16. Break thermal efficiency increases with load non-linearly and shows high efficiency of 28% at 10 kg load for all compression ratios with B20. It has also been observed that break power increases linearly with load for all blending ratios and compression ratios. Exhaust gas temperature also increases with load and is comparatively less for lower blending ratios such as B10 and B20 than the higher blending ratios ranging from 30B to 50B. NO emission shows parabolic behaviour with load. Lower levels of NO emissions are observed with low compression ratios. Test shows that CO emission level decreases as load increases and low levels of CO emissions are observed when compression ratio decreases. CO emission is highest at CR18 for all blending ratios. CO2 emission levels obtained through analyser shows that the less amount of CO2 is emitted at the exhaust with all blending ratios and at higher compression ratio. Moreover, CO2 emission increases and then decreases with load. HC emission decreases as load increases and it is highest at lower compression ratios.