Yanmar H2 high-speed engine earns certification

Left: Demonstration model of a pilot ignition hydrogen four-stroke high-speed engine; right: Rendering of the engine. (Source: Yanmar Power Solutions)

Yanmar Power Solutions Co., Ltd., a subsidiary of Yanmar Holdings, said it has become the first engine manufacturer in Japan to obtain both a type approval certificate and NOx certificate from Nippon Kaiji Kyokai (ClassNK) for its pilot ignition, hydrogen-fueled, four-stroke, high-speed engine for power generation for domestic coastal vessels.

In 2025, Yanmar Power Solutions was intensifying its land-based demonstration tests utilizing a small amount of hydrotreated vegetable oil (HVO) as a pilot fuel, while preparing for planned demonstration operations. As a result of the inspection by ClassNK, the company successfully obtained type approval certificate in October 2025 and NOx certificate in December 2025, both of which are required for demonstration operations.

Type approval certificate entails conducting assessments, tests and inspections on marine equipment to certify to the manufacturer that the equipment complies with the specified regulations. The NOx certificate is a document that certifies compliance with Tier II in NOx (nitrogen oxides) regulations established by the International Maritime Organization (IMO).

The newly certified engine is part of the Nippon Foundation’s Zero Emission Ships Project focused on the development of hydrogen-powered zero-emission vessels and supports related technology development. Within this framework, the consortium involving Yanmar Power Solutions has been advancing hydrogen engine development, while also developing a hydrogen-compatible hybrid electric propulsion vessel that combines a hydrogen engine generator with batteries.

The engine specifications covered by the certifications are designated as “Electronically Controlled Gas Only Engine (Hydrogen).” Moving forward, the company will install the necessary equipment, including two hydrogen engines, onto domestic coastal vessels, paving the way for demonstration operation trials scheduled for this fall.