UTILIZATION OF n-HEXANOL AND DIESEL BLENDS IN AN UNMODIFIED DIESEL ENGINE-PERFORMANCE, EMISSION AND COMBUSTION STUDIES.

Abstract

Today, the world is in precarious position due to the ever increasing indiscriminate extraction and lavish consumption rate of fossil fuels which in turn are responsible for a filthy environment. This exploitation forced to look for alternate ways to run engines without compensating with the environment and performance, also at the same time they ought to be renewable and sustainable. Among the various developments to combat the problem of swelling emission, the application of oxygenated fuel is an effective way to moderate pollution without any prior modification of the engine. Alcohol which is biobased renewable and oxygenated fuel provides a suitable alternate fuel for internal combustion engines. Alcohols can be blended with both the petroleum based and bio origin based fuels such as vegetable oil and biodiesel. Addition of alcohols reduces dependence of diesel fuel with attractive emission levels. Also alcohol has characteristics that make it a natural engine fuel as it prevents engine detonation under load. In this regard exhaustive research has been carried on alcoholic fuels like methanol and ethanol but little work has been done on exploring the potential of higher alcohols for automotive application Long chain alcohols such as pentanol, hexanol despite their analogous properties have rarely been inspected. Hexanol is a promising long chain compound, as it less hydrophilic and possessing high heating value. High cetane number, low vapour pressure and improved miscibility than ethanol make n-hexanol a preferable component to blend with conventional diesel fuel. The effect of 5% n-hexanol blended fuel by volume reported that many properties like density, flash point, viscosity of the blends are well above the requirement than those of ASTM norms of the diesel engine which further increases efficiency with significant improvements in emissions as well. In the present investigation, four blends of hexanol and diesel were prepared i.e. Hx05D95, Hx10D90, Hx15D85, and Hx20D80. All the blends were found to be homogenous and stable. The calorific value of all the blends was found to be slightly lesser as compared to neat diesel fuel. The brake thermal efficiency for all the blends was found vi to be slightly higher in comparison to neat diesel. The maximum brake thermal efficiency was obtained with Hx20D80 blend. Similarly minimum brake specific fuel consumption was obtained for Hx20D80 blend while rest of the blends showed a reduction in brake specific fuel consumption. The CO emissions were lower for all the blends. While increasing the hexanol percentage in the blend, CO emission level decreased. However, after 60% load or higher-load conditions, a steep hike in CO emission was observed irrespective of test fuels. Also smoke and HC emissions were low, but higher NOx emissions were recorded. Increased concentration of oxygen within the combustion chamber helps to achieve high in-cylinder peak pressure for all the HxD blends with respect to diesel. The crank angle corresponding to maximum heat release rate shifted rightwards for the hexanol diesel blends as compared to baseline data. It can be concluded from the exhaustive study that a diesel engine, without any modifications, can run successfully on hexanol-diesel blend fuel without externally apparent damage to the engine parts. Nevertheless, to recommend its use as a substitute of straight diesel fuel, long-term durability tests are required.