Rolls-Royce launches B36:45 pure gas engine

Power output of the LNG-fuelled engine, which uses lean-burn Otto cycle combustion technology, is identical to that of the liquid-fuelled B33:45, at 600kW per cylinder (at 750 rpm). Specific energy consumption is 7300kj/kWh and lubricating oil consumption is less than 0.4g/kWh.

The engine is available in six, eight and nine-cylinder in-line configurations. A V12 version is now in development, which will be followed by a 20-cylinder V-engine for very high-power applications.

Kjell Harloff, senior vice president – engines, Rolls-Royce Commercial Marine, said: “This new engine offers a variety of new benefits to our customers, including rapid response to changes in load and speed, high reliability and clean burning. This makes the B36:45 ideally suited for mechanical ship propulsion installations, driving either controllable or fixed-pitch propellers. The engine is equally at home operating at constant speed driving alternators in gas-electric propulsion or auxiliary power generation systems.”

The main structural components are the same as those used in the B33:45 liquid fuel engines. The crankcase incorporates all air and oil galleries, minimising external pipework and ensuring stiffness and operational safety. Individual cylinder heads and three-piece connecting rods allow the complete head, liner, piston and upper conrod to be withdrawn for overhaul and replaced without disturbing the engine bottom end.

Different liners, pistons and heads give a 30mm increase in cylinder bore compared with the liquid-fuelled B33:45 while the stroke remains unchanged, at 45cm. Other changes involve the fuel system and injectors, while a robust variable valve timing system allows optimum response to load changes, regardless of the fuel quality.

Leif-Arne Skarbø, chief technology officer, Bergen Engines, added: “Benefits for end users and shipbuilders arising from this modular approach are that the product is configurable and production is simplified, resulting in a highly competitive cost per kW and straightforward installation and maintenance.”

The B36:45 meets IMO Tier III and EPA Tier 3 NOx emission limits without the need for aftertreatment. It can achieve up to 22% lower greenhouse gas (GHG) emissions than the equivalent diesel-fuelled version.

As reported previously, the engines will be part of a major environmental upgrade programme Rolls-Royce is conducting with Norwegian cruise and ferry operator Hurtigruten to reduce CO2 emissions in the owner’s fleet by 25%.

Under the agreement the main engines on up to nine Hurtigruten cruise ships will be converted from diesel to gas power. The upgrade will also include installation of hybrid battery systems, with Rolls-Royce also recently entering the business of marine battery production, The intentional agreement specifies that Rolls-Royce is to deliver two of its Bergen B36:45 gas engines as the main engines to each ship.