Type approval for MAN four-stroke engine

13 May 2015
The dual-fuel, four-stroke L35/44DF engine will now proceed to factory acceptance testing in Frederikschavn

The dual-fuel, four-stroke L35/44DF engine will now proceed to factory acceptance testing in Frederikschavn

MAN Diesel & Turbo’s new L35/44DF four-stroke engine has been approved by all major classification societies for genset and controllable pitch propeller operation, after type approval tests between 30 March and 2 April.

The type approval, observed by representatives from ten classification societies, means that the company can now proceed with factory acceptance testing. This will be carried out at MAN’s facility in Frederikshaven, Denmark.

The new engine features a 350mm bore, 440mm stroke and 42.3l swept volume per cylinder. It is available in 50Hz and 60Hz models with six to ten cylinders, and boasts a power range of 3.06-5.3kW (see graphic for technical data).

Dr Günter Heider, senior manager and head of test & validation four-stroke diesel & gas engines for MAN Diesel & Turbo, reported: “The 35/44DF showed a spotless overall performance without any unplanned quick changes over from gas to diesel during operation or any of the type approval tests.

“Among the features that were specifically appreciated and praised by the association members were the quick changes over from gas to diesel mode at 100% load; the restriction-free gas load performance at an overload of 110%; and the engine’s logic and clear modular design.”

The engine was put through three tests during type approval. The extreme conditions test subjects the engine to minimum oil pressure, maximum temperature and 110% performance, with a cyclic loading operation over 40 hours and a one-hour full-torque test at 87% of the nominal speed with a shutdown by engine overspeed.

In the emergency operation test the engine is observed in non-supercharged conditions (i.e. as a suction engine) for one or two days. And in the final type approval test the engine’s ability to perform under various loads and switch smoothly from diesel to gas operation and back is tested, along with the alarm and safety system and an integration test to show reliability in the event of control system failure.

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