A world first: Weichai certifies a heavy-duty hydrogen combustion engine to China's strictest standard

China's Weichai Power has reached a notable milestone: the WP15, a heavy-duty hydrogen combustion engine, is the first in the world to be certified to China's strict China VI emission standard. On 3 July 2026 the engine passed all core tests at an accredited test centre in Tianjin. It shows that hydrogen offers a clean route for heavy-duty work not only through the fuel cell, but also through the combustion engine.

What is a hydrogen combustion engine?

In a fuel cell, hydrogen is converted into electricity, after which an electric motor drives the wheels. A hydrogen combustion engine works differently: it burns hydrogen directly in the cylinders, just as a diesel engine does with diesel. Weichai uses in-cylinder direct injection with spark ignition. The big difference with diesel: almost no CO2 is released, because there is no carbon in the fuel.

Powerful and efficient

The WP15 has a displacement of 14.6 litres and delivers 600 hp (447 kW) with 2,800 Nm of torque — ample for heavy transport. Its maximum efficiency reaches 46.8%, a high figure for a combustion engine. More efficiency means less fuel is needed for the same work.

Virtually emission-free

According to Weichai, the engine emits no direct CO2 across virtually its entire operating range. Nitrogen oxide (NOx) emissions stay well below the standard thanks to the smart direct hydrogen injection, and only a simple aftertreatment system is required. In this way the engine combines high power with very low emissions.

Smart: over 90% shared with a diesel engine

A strong point is that more than 90% of the parts are the same as in an ordinary diesel engine. That lowers the costs of production, conversion and maintenance, and makes it easier for hauliers to switch. Existing production lines and workshops can largely stay the same.

Runs on lower-purity hydrogen too

The WP15 runs stably on hydrogen of lower purity than many other systems require. That reduces fuel costs and makes the engine easier to deploy in practice.

From truck to generator

The engine is intended for a range of heavy-duty work: long-haul trucks, mining trucks, port sites, steel mills and large generators. Together with Sinotruk, Weichai already launched the first commercially available truck with a hydrogen combustion engine, and it realised the first grid-connected generator running entirely on hydrogen.

Why this matters

This certification shows that there are several clean routes to heavy transport. Alongside battery-electric and the fuel cell, the hydrogen combustion engine is an attractive option, precisely because it stays close to familiar diesel technology. For applications that need a lot of power and fast refuelling, this is a practical and affordable way to move towards zero emissions.

Sources

• Ctinsa – "A Global First: Weichai Hydrogen ICE Achieves Groundbreaking Breakthrough" (2026)
• Automotive World – "Weichai certifies world's first China VI hydrogen engine"
• Weichai Power – press release WP15 hydrogen engine (July 2026)