Rolls-Royce has developed a new range of medium speed engines and the first to be launched is the Bergen B33:45, which was revealed at the SMM exhibition in September. Initial models will burn liquid fuel but future versions will be able to burn gas. The new engine range follows three years of development work involving collaboration on the technology with Rolls-Royce group companies MTU and Bergen Engines. The engines will be built at the Rolls-Royce plant in Bergen.
The first commercial sale of the new range is a nine cylinder B33:45L9P, installed aboard a stern trawler of Rolls-Royce Marine’s NVC370 design for Norwegian owner Prestfjord Havfiske and due to be delivered in June 2015.
It will ultimately be available in six- to nine-cylinder versions, with Vee configured versions also being developed. The engines can be used either as main propulsion or gensets. The design is common rail-ready and this option is expected to be available in two years’ time.
The first L6 model is planned to be delivered in the first quarter of 2015, a Bergen Engines spokesman advised Marine Propulsion, with the first L9 model delivered in the second quarter of the year. These dates are earlier than had been announced at SMM, he said. The L8 version will follow in the final quarter, as originally planned, and the first V12 configured engine is expected to be delivered in the second half of 2016, with V14 to follow, along with V16 and V20 versions for power generation applications. The first gas-fuelled variants should be available from 2017.
Mikael Makinen, president of Rolls-Royce Marine, said: “This is a totally new engine range. It is focused on meeting customers’ demands for lower operating costs and through lifecycle costs. It is a real step change in efficiency. This completely new modular engine architecture gives us an engine family that is truly engineered for the future, with numerous configurations and multiple fuel options.”
Thor Humerfelt, programme director, said: “When we embarked on this engine programme, we knew we could deliver a set of real performance improvements by moving to a new design.” He said that talking to owners resulted in reduced lifecycle costs being the overriding design goal for the new range, with other design goals flowing from that.
The new design features a 20 per cent increase in power output per cylinder, up to 600 kW/cyl compared with the 500 kW/cyl of the current Bergen B32:40 series. This power output is the same for both liquid- and gas-fuelled versions. Both versions have a common engine block and a 450mm stroke, but the liquid fuel engines have a 330mm bore while the gas engines will have a slightly higher 360mm bore. The planned models of between six and nine cylinders will offer a power range from 3,600kW to 5,400kW. The Vee configuration versions will have a power range of 6,000kW to 8,400kW for marine applications.
Fuel consumption is also lower at 175 g/kWhr at 85 per cent load, and 177g/kWhr at 100 per cent load at a speed of 750 rpm. Running speed for propulsion is between 450 rpm and 750 rpm.
Mr Humerfelt said that its reduced vibration combined with reduced fuel consumption, longer service intervals and ease of servicing will result in lower lifecycle costs. It also offers reduced emissions and is compliant with IMO Tier III, with a combined selective catalytic reduction system. Smoke remains invisible at low loads.
“There was a clear requirement to comply with the US Environmental Protection Agency (EPA) emissions regulations. This involves a lot of work but there are no technical issues to meet EPA compliance,” Mr Humerfelt advised.
The liquid fuel design, which is able to burn HFO or MDO, features pump line nozzle injection and has 100 per cent power take out at both ends including for the in-line and Vee configurations.
The engine has been designed with capability of meeting the transient performance required for marine gensets, with three steps on loading as standard and two steps as an option. The variable valve timing inlet system, which responds to load, ensures the engine receives the optimum air for maximum responsiveness and efficiency.
The in-house electronic engine management system monitors and controls all key engine functions and exhaust after treatment. A new turbocharger is matched to the exhaust system, which provides multi-pulse charging with charge air taken through a two-stage intercooler, giving a high turbo efficiency.
Mr Humerfelt also highlighted the compact design. Despite increased power, the new engines occupy the same footprint as earlier engines, with the in line version featuring a cylinder distance of 520mm, while the modular design and reduced piping complexity simplifies production, installation at shipyards and maintenance.
According to Rolls-Royce the service interval for main overhauls is every 20,000 hours, increasing to 25,000 hours when the average engine load is below 60 per cent. The piston lifetime is 60,000 hours increasing to 75,000 hours for low average loads.
Mr Humerfelt said that the new engines are suited to offshore vessels including anchor handlers, seismic and subsea construction vessels, semi submersibles and drillships, and some commercial vessels such as ropax ferries, cruise ships, cargo ships and fishing vessels. MP
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