Caterpillar's 3500 engine series has been a workhorse in the commercial marine industry since its initial manufacture in the 1970s. It will now be taking on new life, in the form of the 3512C and 3516C diesel-electric-propulsion (DEP) engines, more proof, Cat says, of its commitment to sustainable development.
Available for a variety of commercial applications and megayachts, the DEP engines build on the reliability and durability, not to mention longevity, of the 3500 engine platform while meeting U.S. EPA Tier 2 and IMO (International Maritime Organization) Tier I regulations.
Manufactured at the Lafayette Engine Center in Lafayette, IN, the constant-speed DEP engines offer electronic-unit-injection (EUI) fuel-system capabilities and ADEM A3 Electronic Control Units (ECU). The V-12, four-stroke 3512C engines are available at 1360, 1550, and 1700 ekW, and the V-16, four-stroke 3516C engines are available at both 2000 and 2250 ekW.
All engine ratings are certified to the E2 emissions cycle. The electronic “power station” concept creates efficiencies between the control units, unit injectors, instrumentation, and displays to perfectly balance power supply, fuel consumption, and exhaust emissions at any given load. According to Cat, electronic power generation presents a clear advantage over traditional diesel counterparts by "drastically reducing the CO2 emissions as a result of efficiency gains from better power and load management."
Cat also says operators will benefit from the DEPs in terms of increased safety, lower noise and vibration levels, and driving efficiencies via electronic technology and the overall system design.
However, it also cites that the largest benefit of the DEP engines is the redundancy of engine power generation because the diesel-electric engines are turned on only as they are needed. Thus, if an engine is lost, there is still enough power generated to provide power for shaft lines and vessel electronics. Also, says Cat, the EUI fuel system capabilities and ADEM ECU deliver more available power while achieving enhanced fuel efficiency.
In terms of maintenance, the time between overhaul is increased as DEP engines are not always running at full load and there is no physical contact with propeller and engine. These features contribute to a reduction in overall cost and maintenance for the vessel owner, "putting more focus on the voyage ahead and less worry about the operation of the engines," says Cat.
In addition, the emissions levels achieved with DEP engines enable shipping companies to obtain special environmental certification with the Marine Classification Societies, such as DNV Clean Design, GL Green Passport, LR Character N, or the German Government’s Blauer Engel. These environmental classes contribute to reduced harbor fees in some parts of the world.
Since launching the DEP engines last year, Cat says its dealers have received increasing interest in the diesel-electric option because they can provide all necessary components to develop a turn-key solution, including transfer switches and switchboards.