Karanja oil utilization in a direct-injection engine by preheating. Part 2: experimental investigations of engine durability and lubricating oil properties

Abstract

Straight vegetable oil utilization as a diesel engine fuel has the advantages of eliminating the energy, time, and cost involved in biodiesel production. Since straight vegetable oils have quite high viscosity compared with mineral diesel, they have to be modified to bring their combustion-related properties closer to mineral diesel. In this experimental study, a heat exchanger was designed and used to utilize the waste heat of exhaust gases for reducing the viscosity of Karanja oil by preheating. Carbon deposits, wear of vital engine components, and various effects of utilizing preheated Karanja oil on lubricating oil were analysed during a long-term endurance test executed for 512h. Carbon deposits on various critical parts of the power cell were analysed by visual inspection. For pistons, the piston merit rating was determined. The effect on a lubricating oil because of heated Karanja oil vis-à-vis mineral diesel was evaluated by comparing the densities, viscosities, flash points, carbon residues, ash contents, copper corrosion effect and pentane, benzene insolubility measurements at intervals of every 128h for 512h. The wear of the cylinder liner, piston rings, gudgeon pin, and small- and big-end bearings for a Karanja-oil-fuelled engine were also measured and compared vis-à-vis mineral diesel-fuelled engine.