Marine and industrial Sulzer medium speed engines of AL20 and A25 series

Zaklady Przemyslu Metalowego (ZPM) H.Cegielski in Poznan, Poland, have obtained licence for production of various medium speed engines of AL20 and A25 series from Sulzer Brothers Ltd., later New Sulzer Diesel and then Wartsila.
Old, well proven design, reliability and ease of maintenance has made them very popular in many applications.

HCP Sulzer - it is worldwide recognized brand.

Most of the engines work in auxiliary power generators on ships, some as stationary power source (especially popular in India as recovered from scrapped ships and rebuilt), many as main propulsion in many tugs, floating cranes, fishing ships and another workboats.

• AL20 series: cylinder diameter 200mm, stroke 240mm, speed 700-1200 RPM
  Still produced at individual order in many variants
  Fuel: Heavy Fuel Oil (HFO), Marine Diesel Oil (MDO) and gas (including gas recovered from landfills)
  6 cylinders version: 6AL20/24, 8 cylinders version: 8AL20/24

   

• A25 series: cylinder diameter 250mm, stroke 300mm, speed 700-1200 RPM
  Arrangements of cylinders: L and V

   

  • A25/30 series: cylinder cover with 1 inlet and 1 exhaust valve. The longest in constant production.
    Fuel: MDO only
    Samples of marking:
    3AL25/30 (only several have been built), 5AL25/30, 6AL25/30, 8AL25/30
    12AV25/30, 16AV25/30

     

  • AS25 (AS25/30) series
    They have cylinder cover with 2+2 valves. For HFO version of engines, the bore-cooled cylinder cover was introduced
    This type was not the biggest success, especially first ones, working with MDO only, without bore-cooling of cylinder covers.
    Currently they are the most popular as recovered from scrapped ships and rebuilt for local electric power generation in India.
    Production is stopped
    Fuel: MDO and HFO
    Samples of marking:
    6ASL25 D, (MDO, 6 cylinders), 8ASL25 H (HFO, 8 cylinders)
    12ASV25, 16ASV25

     

  • AT25 (AT25/30) series, they are modernized version of AS25H series.
    They have bore-cooled cylinder cover with 2+2 valves. Currently engines AT25 are the most powerful among Sulzer A25 engines and are still produced.
    Fuel: MDO and HFO
    Samples of marking:
    6ATL25 D (MDO, 6 cylinders), 8ATL25 H (HFO, 8 cylinders)
    12ATV25, 16ATV25

Engines Sulzer AL20 and A25 series have been built in Poland, Yugoslavia and probably in some other countries around the world.