Low fuel consumption is given in the ATL25 by applying the latest developments in turbocharging technology, involving:
high-efficiency turbochargers of the Brown Boveri RR-series radial design. These are completely uncooled, and have plain bearings with lubricating oil supplied from the engine’s system;
single-pipe exhaust system which gives a practical combination of the advantages of the pulse system, partially retaining the kinetic energy of the exhaust gases, with the simplicity of the constant-pressure system.
This exhaust manifold is assembled from standardized modular elements for each cylinder. The manifold is encased in insulation which can be readily dismantled and also meets fire-protection requirements.
Development of the ATL25 engines systems from the AL25, whose design had begun with the objective of creating robust, simple and inexpensive engines capable of universal application. Continuous development increased the specific power output, increased the running speed and extended the ability to burn increasingly poorer grades of heavy fuel oil.
Further turbocharging developments have enabled significant reduction in the ATL25 fuel consumption. At the same time, service experience and test bed trials have allowed the fuel quality limits to be raised to 700 cSt viscosity for marine auxiliary duties and to 380 cSt viscosity for marine propulsion and stationary applications.