Effect of coolant additives on thermal loading of a diesel engine

Abstract An experimental investigation has been carried out to evaluate the heat transfer performance of three engine coolants and their mixtures with distilled water under real engine conditions. The coolants and their mixtures with water are used in a single-cylinder diesel engine running on gas oil fuel. Heat flux and wall temperatures were measured in the critical areas of the cylinder liner and cylinder head using traverse thermocouple probes. Coolant performance is defined as the ability to maintain a lower wall temperature for a given heat flux. Test parameters included coolant concentration in distilled water, engine load (heat flux), coolant flowrate and coolant type under forced convection and subcooled boiling conditions. Results showed that the coolant performance is critically affected by the coolant constituents, heat flux transferred and flow velocity. The best coolant for the cylinder head and cylinder liner is put forward.