Abstract
It is not only fuel and lube oil costs which determine life cycle costs of a diesel engine, but also maintenance costs and costs for replacements of wear components. All these costs are linked to the individual design of the engine and its capability to burn a variety of fuels, including low-priced heavy fuel oils. As an example, the paper describes several main components of MAN B&W medium-speed diesel engines (engine block, liner, piston) and how they contribute to lower life cycle costs by easier maintenance procedures, longer TBOs and longer life times. To achieve this is a challenging task for the engine manufacturer, since other strong market requirements such as reduced exhaust gas emissions or high power density have to be fulfilled simultaneously.