Ammonia Internal Combustion Engine for Agricultural Machinery Drive Systems

Agricultural machinery manufacturer CLAAS has partnered with engine developer MAN Engines and research institute WTZ Roßlau on the Green Ammonia Multifuel Combine research project. The joint engineering initiative assesses the operational feasibility of an ammonia-powered internal combustion engine to replace fossil fuels in heavy-duty agricultural equipment without relying on pure hydrogen storage infrastructure.

Operational Requirements in Heavy-Duty Agriculture
Harvesting combines and high-horsepower tractors operate under continuous high loads across extended duty cycles, requiring high energy density that battery-electric drivetrains cannot sustain in field applications. While hydrotreated vegetable oil and biodiesel provide near-term drop-in alternatives, long-term defossilization requires scalable zero-carbon energy vectors.

Direct hydrogen combustion introduces severe onboard volume limitations and pressurized storage difficulties on farm equipment. Ammonia serves as a liquid energy vector that contains zero carbon atoms, generating no direct carbon dioxide during combustion. It provides higher volumetric energy density than compressed hydrogen and enables simplified transport and storage, though it requires specialized combustion dynamics, exhaust gas after-treatment, and safe handling controls.




Engine Architecture and Collaborative Workshare
The development consortium divides responsibilities between combustion research, engine adaptation, and machine-level implementation. WTZ Roßlau acts as consortium lead, coordinating project execution funded with 3.2 million euros through the 8th Energy Research Programme via project management organization Forschungszentrum Jülich.

Engine development and fuel-system calibration are shared between MAN Engines and WTZ Roßlau. The technical focus centers on optimizing ammonia combustion behavior, mitigating unburned ammonia slip, and engineering selective catalytic reduction systems for exhaust post-treatment. CLAAS manages vehicle-level integration at its facility in Harsewinkel, adapting machine chassis packaging, vibration damping, cooling systems, and onboard chemical safety protocols to accommodate the multi-fuel power unit.




Implementation Timeline and Energy Evaluation
The project period extends from 1 May 2026 to 31 October 2029, evaluating the entire well-to-wheel pathway from synthetic green ammonia synthesis to mechanical shaft power. Field-level validation will benchmark engine thermal efficiency, transient response times, and fuel consumption across standard agricultural harvest cycles against established diesel performance curves.

Regarding propulsion diversification, Dr Martin von Hoyningen-Huene, Executive Vice President of the Tractor Business Unit at CLAAS, stated: "High-performance machines, particularly harvesting machinery and large tractors operating at full load, will continue to rely on energy-dense liquid fuels in the near future. To reduce the CO2 footprint, alternative fuels such as HVO or, subject to appropriate approval, B100 biodiesel can be utilised using largely existing technology and infrastructure, whilst hydrogen poses greater technical challenges. We would like to explore and better understand the opportunities and limitations of ammonia-powered engines as a potential further part of the solution."

Field testing will determine whether ammonia combustion configurations maintain necessary torque envelopes under varying harvesting loads while adhering to off-highway emissions limits.

Edited by Natania Lyngdoh, Induportals editor, with AI assistance.

www.claas.com