Caterpillar looks offshore with enhanced four-stroke range
Caterpillar Marine has introduced several significant updates to its four-stroke engine range, targeted primarily at the flourishing offshore sector.
First of these is a range of part load kits for the MaK M 32 E, developed specifically for offshore vessels, and available for both constant speed and variable speed operations. Both kits are claimed to combine lowest possible fuel consumption in the part load range with the highest possible power output at full load.
According to Caterpilar Marine, ships such as PSVs and AHTS vessels typically spend a significant period during their lifetime running with limited power demand from the engines, typically using rated power for only 8% of the time. Operating in standby or DP mode often requires the use of multiple engines in combination with low power consumption, resulting in low load operation of two or three engines at the same time. The part load kits offer vessels operating M 32 E engines primarily in the part load range improved fuel efficiency, load acceptance and reduced smoke.
The constant speed part load kit offers fuel savings up to 10g/kWh with a 3x33% load step capability. The kit includes the flexible camshaft technology and intelligent control software integrated into the MACS modular alarm control and safety system.
The variable speed part load kit for M 32 E is based on the constant speed part load kit but with increased fuel savings up to 24g/kWh, achieved as a result of the reduced engine speed at lower loads. Key components include a modified turbocharger, cylinder bypass valve and waste gate.
“It was a big challenge for us to implement a part load optimisation into the increased power rating concept without sacrificing the reliability and durability MaK marine engine platforms are known for,” said Carsten Seeburg, MaK product definition manager. “Additionally, the M 32 E part load kits reduce operating costs and help to improve vessel owner bottom lines.”
“For our offshore customers operating their ships in the part-load range, the need to be able to provide the lowest fuel consumption possible is paramount,” Seeburg noted. “In these applications, the maximum power output is typically needed less than 8% of their annual operating hours. However, if the vessel needs to go full throttle, the operator can rest assured that the M 32 E engine optimized with a part load kit is more than capable of providing the thrust needed.”A new version of the MaK M 25 engine platform, the M 25 E, was launched at the recent SMM exhibition in Hamburg. The company says the new engine was developed with an emphasis on fuel savings, and designed to address the evolving industry requirements in the offshore and coastal cargo market sectors, while maximising operators’ bottom line.
The engine is designed for both mechanical – with either FP or CP propellers - and diesel electric propulsion applications, as well as gensets. Key product features include optimised engine performance as well as an efficient part load range, which is said to help to save up to 40t of fuel a year when operating vessels at variable engine speed. By a change in operating mode ships operating at low loads can increase the potential savings to around 60t/year. The increased efficiency comes thanks to the incorporation of a range of fuel-saving technologies such as flexible camshaft, waste gate technology and cylinder bypass valve.
Caterpillar senior product definition engineer Detlef Kirste said: “The reliability of the new MaK 25 E is assured, given that it is based on the legendary M 25 C platform. In addition to adding a 5% power increase and reducing the fuel consumption on this platform, we also engineered the M 25 E to capitalise on the synergies between the engine, vessel and propulsion system.”
The M 25 E will be made available in six-, eight- and nine-cylinder inline configurations offering ratings between 2,100kW and 3,150kW at 720rpm and 750rpm. All versions are said to offer low smoke emissions and to be compatible with SCR technology for future IMO Tier III requirements. Equipped with the MACS modular alarm and control system, the M 25 E supports remote condition monitoring and diagnostic maintenance programs.
The company says the M 25 E is particularly well suited to vessels with optimised hull and propeller designs and those with varied load profiles, particularly where low-load operation is frequent.
“The M 25 E has a very high torque to speed ratio allowing operators to run their CP propellers at a reduced propeller shaft speed significantly increasing the propulsive efficiency and lowering fuel consumption,” said propulsion sales manager Jonas Nyberg. “The improved load response also makes them the ideal engines for any demanding transient operations such as Dynamic Positioning."
Another in the company’s four-stroke propulsion range, the 175mm-bore C175 high-speed propulsion engine, has received a recent upgrade. The C175-16 propulsion engine, targeted at applications such as harbour tugs, is now available with ratings of 2,239kW to 2,550kW at 1,800rpm, extending the power of Cat’s high speed range beyond the 3516C HD engine.
The new engine employs Cat’s ACERT technology to optimise turbocharging and aftercooling efficiency, as well as the Cat common rail fuel system to minimise emissions. It also benefits from extended service intervals and improved access to key components for maintenance.
At the same time, a significant tug order was announced, with the award of a contract for 16 MaK M 25 C eight-cylinder propulsion engines to power eight 70t bolard pull tugs, being built for Transnet National Ports Authority at a South African shipyard. Each of the 31m tugs will have a total power of 5,332kW.
Caterpillar claims that its MaK engines are well suited to tug applications, with good load response capabilities, low fuel consumption and long service intervals, while the reduced component count and simple design simplifies maintenance.
The 3516C engine is now available with US EPA Tier 4 certification for mechanical propulsion, auxiliary and diesel electric propulsion installations. EPA Tier 4 certification means that the engines are also IMO Tier III compliant. The Tier 4 certified engine is available in a ‘B’ rating of 2,240KW and a ‘C’ rating of 2,350KW, with the auxiliary and diesel electric versions rated 2,250kWe, all at 1,800rpm.
The Tier 4 engines are said to combine SCR exhaust after-treatment with an optimised engine for low NOx emissions. Cat’s ‘Clean Emissions Module’ incorporates SCR technology designed for compactness and low capital and operating cost. The Tier 4 version thus shares major componebnts and footprint with the existing EPA Tier 2 and Tier 3 engines.
Another new four-stroke launch for the company at SMM was the C4.4 ACERT generator set, intended primarily as an emergency genset for commercial vessels. It employs a fully-electronic power unit designed for improved transient response and load acceptance. Power ratings are 65-99kWe at 50Hz and 60-118kWe at 60Hz.
It uses similar technology to the C7.1 ACERT unit, but with an 18% power density increase. The older mechanical version of the C4.4 will still be available for applications where emission requirements are less strict.
Designed for fail-safe operation, ease of use, long service intervals and simple installation, the UK-built C4.4 ACERT has a high pressure common rail system and is EPA Tier III certified.
Caterpillar Marine’s current focus on the offshore industry is underlined by the fact that it has now sold 100 gensets featuring Brazilian local content from the company’s Piracicaba, Brazil manufacturing facility. The company has had a presence in Brazil since 1954, with its present
Piracicaba facility opening in 1973. It currently offers the Cat 3500, C280, and CM32 product families, with a power range up to 9,200kVa, but has capacity for building up to 70 1MW-plus units per year.
Cat has not been inactive in the gas-fuelled market either. As well as dual-fuel MaK engines, the company, still looking towards the growing Brazilian market, says that its first Cat 3512C marine generator sets with its dynamic gas blending (DGB) technology have been chosen to power one of seven fast ferries for Assessoria Transporte Aquaviaro. These have been ordered in respect of the 2016 Olympics in Rio de Janeiro, and will be constructed by Afai Southern Shipyards in China to a design by Dutch boat designer Coco Yachts.
Each ferry will have two Cat 3512 gensets, with two more Cat 9 gensets providing prime and auxiliary power. One of the ferries will be equipped with the new Cat marine dual fuel solution and powered by CNG. The other six ferries are being constructed with the option to retrofit the DGB kits.
Cat dealer Pon Power led the project and will provide support, packaging and commissioning. “We, as Pon Power, see gas as the future fuel for marine. We are happy to materialise the customer needs of Coco Yachts together with Caterpillar Marine,” said Thomas de Haas, Pon Power director marketing and new business development.
The Cat 3512 DGB generator set features a low pressure gas system with about 70% maximum gas substitution rate across a wide load range. The IMO II-compliant unit operates with diesel-like rated power and transient response while maintaining an overhaul life similar to a diesel engine. The technology has been used for some time in land-based applications, and the 3512 DGB generator set, rated at 1,550kWe, is available to order.
“The new Cat Marine dual fuel solution leverages the proven durability of the 3500 diesel engine while offering customers enhanced fuel flexibility and power redundancy to run diesel or gas,” said Jason Spear, Caterpillar Marine product definition engineer.
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