EPA Tier 4: Lower NOx, particulate and hydrocarbon emissions
For each of the three 44 meter catamarans, mtu supplied six 16-cylinder Series 4000 units, six mtu SCR systems and six ZF transmissions. All three vessels are also to be equipped with mtu BlueVision ship automation systems. Each engine will deliver 2,560 kW of power at 1,800 rpm, powering the twin-hulled vessels up to speeds of 34 knots. The ferries are being built by the Dakota Creek Industries shipyard, and as they are destined for service in the San Francisco Bay area, the engines that propel them are expected to meet the EPA Tier 4 emissions standard which came into force in the US on 1 January 2016. This demands substantially lower NOx, particulate and hydrocarbon emissions than was the case with the previous requirements.
The integrated propulsion system comprising Series 4000 diesel engines with mtu's own SCR exhaust gas aftertreatment system for compliance with IMO III and EPA Tier 4 emissions standards is a major step forward in cutting emissions. Advances in turbocharging, combustion and fuel injection, combined with the new SCR system, have facilitated a 75% reduction in NOx emissions compared to IMO II, and a 65% reduction in particulates compared to EPA Tier 3. There is no need for an additional diesel particulate filter, and fuel consumption is up to 5% lower than that of the engine's predecessor. The power range of the various cylinder configurations is between 1,380 and 3,220 kW.
20 years of teamwork and over 30 engines
Rolls-Royce and the San Francisco Bay ferry operator have been collaborating since 1997, ably assisted by mtu distributor Pacific Power Group. Today, WETA operates its passenger ferries with the aid of over 30 mtu Series 2000 and 4000 engines.