CS21 Series marine diesel engine is a medium-speed, four-stroke marine propulsion engine developed by the 711 Research Institute in cooperation with international marine engine design partners.

Featuring a cylinder bore of 210 mm and a piston stroke of 320 mm, the CS21 series delivers a power range from 1100 kW to 1760 kW, providing reliable performance and high efficiency for marine propulsion applications.

The engine adopts advanced fuel injection systems including mechanical high-pressure pump injection and high-pressure common rail technology, ensuring optimized combustion performance and compliance with IMO Tier II emission standards. With a compact modular design and strong adaptability, the CS21 series is widely used in tugboats, fishing vessels, dredgers, Ro-Ro vessels, container ships, bulk carriers and offshore support vessels. All models can be supplied with classification society certificates upon request.