MAN L35/44DF CD gen-set passes type approval test

MAN Energy Solutions announced the successful Type Approval Test (TAT) of its dual-fuel MAN L35/44DF engine for application as auxiliary generator set and electric propulsion at constant speeds of 720 and 750 rpm, respectively. The testing involved both the methane-capable (35/44DF CD) and methanol-ready (35/44CD) engine variants.

Group photo from the TAT at STX in April 2025 including MAN Energy Solutions and STX personnel, as well as representatives from British Lloyd’s Register of Shipping (LR), American Classification Society (ABS), DNV Classification Society, French Classification Society (BV), Chinese Classification Society (CCS), and Taiwan China Ship Inspection Center (CR). (Photo: MAN Energy Solutions)

The L35/44DF CD is an upgraded version of the L35/44DF CR engine, which was first launched in 2015. Among other features, it comes with an Adaptive Combustion Control (ACC) system that monitors the state of combustion in real time for optimal fuel injection conditions.

The TAT took place from April 7-11 at the Changwon, South Korea, headquarters of STX Engine, with the participation of six classification societies.

According to Alexander Knafl, senior vice president, MAN Energy Solutions, the company worked closely with STX for the past three years in developing the 35/44DF. He expected the engine to have broad appeal, particularly for container vessels and LNG carriers.

“In addition to its strong output, other advantages of the MAN 35/44DF CD include its effective reduction of methane slip and its future-fuel readiness for methanol and other fuel types,” he noted.

MAN Energy Solutions reported that the 35/44DF CD generates minimal greenhouse gas emissions and, compared with industry standards, can reduce methane slip by up to 85%.

In addition to its future-proof concept, the engine includes the latest technology, including full connectivity and cybersecurity, added Sephardim Koblenz, vice president and head of Licensing, Four-Stroke Marine & License, MAN Energy Solutions.

“The 35/44DF CD’s reliability, fuel efficiency, low methane-slip and cost optimization are also crucial to the engine’s resumé,” he continued. “In developing this engine together with our partner, STX Engine, we furthermore had low cost and easy localization as clear targets.”