Performance and emission characteristics of diesel-biodiesel-ethanol blends in a heavy-duty compression ignition engine at simulated high altitudes

Abstract

The effects of anhydrous ethanol (E) and castor oil (R) mixed with diesel fuel (D), commercially containing 5% biodiesel by volume, were researched experimentally to evaluate the combustion process and specific fuel consumption in a compression ignition engine, supercharged, six cylinders. In total, three mixtures were used, varying the diesel content from 95% (D95) to 80% v/v (D85), obtaining the following compositions: D95B0E0, D85B6E9 and D80B6.5E13.5. The experimental tests were performed in stationary conditions (1000 and 1800 rpm), two values ​​of effective torque (80, and 160N.m) and two conditions of intake air pressure (100 and 80 kPa). The results obtained show that the mixtures containing ethanol and biodiesel lead to an early start of combustion at 1000 rpm and a delay at the start of combustion at 1800 rpm. The increase in ethanol and biodiesel over commercial fuel does not have any influence on specific fuel consumption; however, the altitude effect generates an increase in specific fuel consumption up to 11% and 7% at 1000 rpm and 1800 rpm respectively. The specific emissions of NOX, CO and CO2are increased with higher specific fuel consumption; in addition, the effect of simulated altitude allowed to verify that at higher altitudes there is a slight increase in sfc and EE of CO and CO2, together with a reduction in EE NOX. At 2000 m of simulated altitude (APCI = 80 kPa) the maximum increases of sfc, CO and CO2, with the mixture D80B6.5E13.5, were 5%, 122% and 18%, respectively. And the maximum reductions in NOX EE were also obtained with the D80B6.5E13.5 mixture, reaching decreases of up to 6%.