Keeping in line with its philosophy of ensuring that all its engines remain ‘state-of-the-art’, Caterpillar has refined its M 20 engine series, which has been successfully established in the market for 14 years, and will now distribute it under the name M 20 C.
Caterpillar began its new advanced MaK long-stroke engine programme with the market launch of the M 20 in 1992. With the three series' M 32 (1994), M 25 (1996) and M 43 (1998) subsequently introduced every two years, MaK diesel engines now cover an output range of 1,020-16,000kW.
As with all MaK long-stroke engines, the units of the M 20 series are optimised to meet the special requirements of ship operation and are reliable and cost-efficient. With their long-stroke design concept and the concentration on fewer components with high function integration, they have proved optimal for installation as both main propulsion unit and marine auxiliary genset in a very wide range of vessels.
As a typical representative of the MaK long-stroke engine family, the M 20 meets current IMO guidelines – NOx emissions with fixed engine timing and without exhaust gas after treatment are definitely below the defined limit value.
An optimal combustion process is achieved with the combination of moderate speed, high injection pressure, high compression and precisely adjusted turbocharging. This results in low specific fuel consumption, heavy fuel suitability and low emissions.
High cost-efficiency is achieved by the interaction of low fuel and lube oil consumption and long component service life. The maintenance intervals are 15,000 hours.
The engines of the M 20 C series are supplied as in-line engines in a 6-, 8- and 9-cylinder version. With an output per cylinder of 170kW at 900rpm or 190kW at 1,000rpm, they offer a performance range of 1,020-1,710kW.
The M 20 series, the smallest series of the long-stroke engine range, is designed for installation as:
• Propulsion engine for small cargo ships (e.g. coastal freighters and inland waterway vessels)
• Propulsion unit for work boats (e.g. tugs, fishing vessels and offshore ships)
• Auxiliary genset for generating electricity on container ships and passenger vessels
Extensive operating experience
Caterpillar Marine Power Systems has sold over 1,100 engines of the MaK M 20 type since its introduction, with 43% being installed as main propulsion plant and 57% as genset or intended for this purpose. The first engine of this type delivered was put into operation in 1992 as the propulsion plant for an inland waterway tanker. The approximate 900 engines installed since then have proved their reliability with an overall service life exceeding 19 million operating hours.
The propulsion engines installed in inland waterway vessels have had the longest service life. Thus, the propulsion engine of the inland water-way tanker (6M20) “Stold Rom” (ex “Alchimist Frankfurt”) has clocked up over 78,000 operating hours, closely followed by the propulsion engine of the pusher craft “Veerhaven VIII” with 77,000 operating hours.
It is worth noting that 57% of the engines deployed as auxiliary gensets and 13% of the units as main engines run on heavy fuel.
New design features
The enhancement includes the following main design modifications:
• Dual-circuit cooling system with easier installation and increased efficiency based on higher cooling water temperatures of up to 90°C
• Simplification of the design of the exhaust gas lines including complete cladding of the exhaust gas system for an even more compact and easily maintainable engine with correspondingly reduced space requirement
• Upgraded turbocharging to a turbocharger with higher efficiency
The success story of the M 20 in the market will be continued with the M 20 C thanks to its design features and simplified maintenance and a further reduction in piping.
Article reproduced with kind permission of Caterpillar Marine News.
