African Mining March - April 2019 | Page 40

Technology Do diesel engines have a future? The diesel engine has become a highly efficient power source — but how much further can it be developed? In this article, Dr Staffan Lundgren discusses whether the humble engine has a future, and if so, what it looks like. D espite constantly being developed over the past century to become a highly fuel-efficient power unit, the diesel engine is now under threat like never before. So, what is the future of the diesel engine? Diffusion combustion — where the combustion is concentrated around the ignition, and oxygen is diffused around the combustion area — is very efficient. It has minimal energy losses to the walls of the engine through radiation or convection — much lower than a gasoline engine. The basic diesel engine is robust and can withstand very high pressures. There have been big improvements, though: jumping from around 35% efficiency in the 1980s to today’s 50% efficiency. That means half of the fuel is now being put into useful mechanical work. For Diesel trucks are still a common sight in most of the opencast mines around Africa. 38 AFRICAN MINING MARCH - APRIL 2019 www.africanmining.co.za