CIMAC provides a forum for technical interchange with all parties interested in piston engines, gas turbine systems, non-shaftline propulsion systems, automation and controls, system integration and digitalisation solutions.^[1] The akronym originates from its French name: Conseil International des Machines à Combustion. CIMAC is a registered association that represents the worldwide interests of the industry in power, drives and propulsion as an umbrella association in dealings with regulatory authorities and standardization bodies. CIMAC was founded in Paris in 1950^[2] and moved its secretariat from London to Frankfurt in 1996.^[3] CIMAC is made up of approximately 500 national associations and large companies from 27 countries in America, Asia and Europe. In addition to manufacturers of large engines and their suppliers, its members also include users of large engines (including shipowners, power plant operators, railway operators), fuel and lubricant manufacturers, universities and development service providers.^[4]

The CIMAC Board prepares decisions which must be approved by the CIMAC Council. The CIMAC Council is composed of delegates from the 15 National Members Associations (NMAs) and 18 direct corporate members. This body also elects the President of CIMAC, who has been elected every 3 years since 1993. Below the management there are 11 permanent working groups which deal with questions and developments in the various areas of the large engine industry and develop position papers, guidelines and technical recommendations. In addition, there is a strategy group greenhouse gas. In 2016, for example, the Fuel Working Group issued a guideline for the uniform analysis of fuels with regard to their sulphur content.^[5] The technical papers produced by the CIMAC working groups are used by organisations such as the International Association of Classification Societies (IACS), the UN International Maritime Organization (IMO) and others in matters of standardisation.^[6] The results of the working groups are regularly presented at international seminars, workshops and the CIMAC Congress.

The central platform for exchange within the large engines industry is the CIMAC Congress. It takes place every 3 years on different continents and at different locations. The latest developments in drive technologies are presented and discussed at the congress. The last CIMAC Congress was held in Vancouver in 2019 and three years earlier in Helsinki. The next CIMAC Congress was scheduled for 2022 in Busan, Korea, but had to be postponed to 2023 due to the COVID-19 pandemic.^[7] It took place in May 2023. The next Congress is schedulded for May 2025 in Zurich/Switzerland^[8]

CIMAC was founded in 1950. The acronym CIMAC is derived from the French Congrès International des Moteurs A Combustion Interne in adaptation to the place of foundation Paris. In the years following the end of the World War II, reconstruction and growth were high on the agenda of many countries. The demand for energy was correspondingly high. The internal combustion engine was regarded as a central component in providing the necessary energy. Technical developments were needed, but nobody knew exactly who in the world was working on what. CIMAC was therefore founded as a forum for greater transparency and mutual exchange in the industry.^[9] CIMAC has in spring 2024 changed its name slightly. The well-known word mark CIMAC, which has been used from the outset, has been retained, but the subsequent explanation “International Council on Combustion Engines” has been dropped. The reason is easy to understand: Although combustion engines are still the core element, in the younger past they have increasingly developed into integral parts of functional systems. CIMAC has taken this into account and widened the scope. Accordingly, CIMAC is the leading global non-profit association promoting the development of ship propulsion, train drive and power generation. The association consists of National Member Associations and Corporate Members in America, Asia and Europe. CIMAC provides a forum for technical interchange with all parties interested in piston engines, gas turbine systems, non-shaftline propulsion systems, automation and controls, system integration and digitalization solutions.^[10]

Since 1951 CIMAC has had 24 presidents:^[11]

• Cimac Congress looks to the Future, Marine Propulsion & Auxiliary Machinery, August/September 2016
• CIMAC´s Executive Decision Roberta Prandi, Diesel & Gas Turbine Worldwide, December 2013
• System Efficiency is the next big Challenge, Karl Woijk, Marine Propulsion, February/March 2014