MAN Engine shows hydrogen ICE for off-road use

At Agritechnica, MAN Engines showcased the MAN H4576, a hydrogen combustion engine based on the proven base of the D3876 diesel engine. The new engine has an output of 500 hp (368 kW) and a displacement of 16.8 L, making it suitable for off-road machines, including those working in agricultural applications.

Shown are exclusive components built into the MAN H4576 hydrogen engine. (Source: MAN Engines)

“Hydrogen combustion engines are a promising approach to accelerate the decarbonization of off-road drives. As soon as the market is ready, MAN Engines will offer tailor-made solutions,” said Mikael Lindner, head of MAN Engines.

The MAN H4576 shares about 80% of the basic components of the MAN D3876 15.3 L diesel engine, such as the crankcase, crankshaft, connecting rods and the cooling and oil circuits including pumps, oil pan and filter. The almost identical dimensions of the two engines make it easier for machine manufacturers to integrate them into existing vehicle concepts, the company stated.

The hydrogen combustion variant has an increased bore from 138 to 145 mm, with the stroke remaining unchanged at 176 mm. The resulting increase in displacement to 16.8 L is required to achieve the target power, given the lower power density of hydrogen engines. New pistons and liners were added due to the larger piston diameter. Other significant modifications were made to components for hydrogen supply and combustion, the engine control system and the exhaust gas control system, MAN Engines explained. In addition, the new turbocharger enables optimum dynamics and helps to reduce fuel consumption.

Kässbohrer Off-Road Vehicles already plans to pioneer the hydrogen ICE technology in its PistenBully 800 vehicle. (Photo: MAN Engines)

The hydrogen injector, which is mounted directly in the combustion chamber, is used for low-pressure direct injection with an injection pressure of up to 40 bar. The specially tuned ignition system enables controlled spark ignition of the hydrogen mixture. The engine control unit controls the supply of hydrogen and air, regulates injection and ignition, and continuously adjusts the engine parameters to enable safe and efficient combustion.

In order to reduce NOx emissions to near zero, MAN Engines is using an advanced combustion process and an exhaust gas aftertreatment system on the new engine, enabling it to meet EU Stage V and Zero Emission Vehicle (ZEV) emission standards.

Because the MAN H4576 is designed as a dual-fuel engine, it can be used in combination with conventional diesel or alternative fuels such as HVO. The company is also developing a stationary hydrogen engine, the MAN H3268, for combined heat and power in combined heat and power plants.