Nanocoolants for engine cooling system

Abstract

The automobile industry is constantly looking for increasing engine efficiency while complying with stringent emission norms. One such aspect studied in great detail is the effect of engine coolant temperature on fuel efficiency and emissions. It has been shown that coolant is responsible for maintaining the engine at optimum operating temperatures in addition to warming up the engine at start. In view of this, nanofluids have been proposed as potential replacement for conventional coolants based on their extra-ordinary lab-scale performance, however studies reported in literature are inadequate to predict the effect of nanofluids in automobiles. We have developed a process for large scale production of stable nanofluids using high energy milling. Using this top down approach, we have converted commercial engine coolants into nanocoolants. This study presents a comparison between commercial coolants and nanocoolants with respect to break specific fuel consumption (bsfc), log mean temperature difference (LMTD) of the heat exchanger (radiator) circuit, amount of NOx (ppm) and O2 (% vol.) in the exhaust gas. This study is performed on a three cylinder, direct injection, 38.5 bhp diesel engine test rig equipped with a hydraulic dynamometer. Addition of nanoparticles exhibits an enhancement of about 2-3% in LMTD, while brake specific fuel consumption and extent of oxygen in the exhaust gas decreases when nanocoolant is used.