Retrofit optimises slow steaming
The MAN EcoCam
“Slow steaming is now an established industry standard across all segments, including the tanker and bulker markets, and MAN Diesel & Turbo continuously seeks to further refine its technology and improve efficiency,” remarked Christian Ludwig, head of Retrofit & Upgrade at MAN Diesel & Turbo. “The MAN EcoCam adjusts the exhaust-valve timing between 10 and 60% load, giving a 2-5 g/kW fuel saving with minimal to no interruption to a vessel's schedule during installation.”
MAN Diesel & Turbo is initially rolling out the MAN EcoCam to a number of its MAN B&W S50MC-C engines and will eventually introduce it stepwise to its mid- and large-bore engine programme.
As the company explained, the MAN EcoCam introduces a flexible cam profile, called a virtual cam. The profile is controlled hydraulically by adjusting the amount of actuator oil in the hydraulic pushrod. Low-load tuning has an impact on torsional vibration and NOx. When a low-load tuning method is installed on an engine, the torsional vibrations’ impact and the NOx level have to be taken into account to ensure that the vibrations’ impact is not harming the engine and that the NOx level is in compliance with IMO regulations.
The new torsional vibration calculation and NOx amendment are included when buying the MAN EcoCam.
The EcoCam’s effect on fuel reduction has been verified by two independent testbed installations and on board a test vessel in service, according to MAN Diesel & Turbo. The earlier closing of the exhaust valve provides a higher compression pressure, thereby delivering a higher combustion pressure and lower fuel-oil consumption. Flexible exhaust-valve timing has traditionally only been available to electronically controlled engines.
Depending on an engine’s load profile, the company says, the MAN EcoCam typically generates savings in the range of 2-5 g/kWh. For smaller engines, this can result in a payback period of as little as one and a half years, as is the case, for example, with a 6S50MC-C engine with 6,000 annual running hours.
