Staying up with the times: more power for off-road applications
With the launch of a new combustion engine, the D9612, specially developed for demanding off-road applications, Liebherr focuses on agricultural machinery.
The D9612 delivers a maximum power output of 950 kW and combines robust performance with high efficiency. It is designed to operate reliably under challenging conditions and offers notable improvements not only in fuel consumption, but also in the reduction of emissions. The engine is suited for applications in agriculture, industry and construction, addressing the diverse needs of these sectors. The brand-new D9612 is on display at the components’ booth 326 in hall A4 at this years’ Bauma.
Improved engine dynamics with hydraulic air boosting
Emissions caused by combustion engines pose a challenge on construction machinery and the environment. Lean mixture engine operation stands out as a promising solution to meet future regulations. This means that an engine runs with excess air, delivering lower emissions, while maintaining the same performance as a conventional diesel engine.
However, this mode of operation can affect engine dynamics. To address this, Liebherr has developed an innovative system: the hydraulic air booster. The system recovers hydraulic energy and uses it to power a mechanical compressor, when needed. When power is required quickly, the system is activated, and the compressor forces additional air into the engine, reducing turbo lag and offering a quicker response to the power demand. The engine can therefore operate at optimal engine efficiency, lowering its fuel consumption.
"In our machines, we transmit power using pressurised hydraulic fluid. Certain movements require the release of pressure, which results in energy loss,” explains Bouzid Seba, head of predevelopment at Liebherr Machines Bulle S.A. “Our innovation does not only allow to recover and store this energy, but also to use it subsequently on demand in our hydraulic air booster. When needed, the air booster pushes large quantities of air into the motor to help it deliver power quickly. Consequently, our innovation increases engine efficiency and performance," concludes Seba.
This technology also has the potential to benefit future engines powered by alternative fuels. Hydrogen combustion engines can operate efficiently with a high level of excess air. This significantly reduces the need of exhaust after-treatment, diminishing the engine dynamic performance at the same time. The hydraulic air booster can help the engine deliver power quicker and match current diesel performance. Even ammonia engines, which show good dynamic behaviour, could also benefit from this technology. Through the reduction of the engine operating speed, efficiency increases, while fuel consumption drops.
Powering the future: Liebherr’s emissions-free solution for today
The reduction of global greenhouse gases is a significant challenge of the present generation. Striving to reach net zero emissions in the future, Liebherr works on alternative and climate-friendly powertrain concepts.
Liebherr’s components product segment has recently made a significant investment in the development of hydrogen engines and test facilities. Since 2020, prototype engines have been undergoing testing, showing encouraging results in terms of performance and emissions, both on test benches and in the field. Different injection and combustion technologies, such as port fuel injection (PFI) and direct injection (DI), have also been assessed in the process. Initial efforts in the development of a hydrogen engine have considered PFI as a first suitable technology. The 6-cylinder engine prototype H966 exhibited at the components’ booth 326 in hall A4 of this year’s Bauma is equipped with said technology.
Exploring the future with ammonia
At Bauma 2025, Liebherr is presenting its concept of an ammonia engine. Focusing on market requirements, the components product segment has undertaken research activities with ammonia as a power source for dual-fuel internal combustion engines. The achieved results clear the path for further development of the solution. Green ammonia serves as a hydrogen carrier, offering the benefits of reduced transportation and storage costs. Generators and potential off-road powertrains fuelled by green ammonia could provide low- or zero-emission solutions for supplementing on-site power supplies. This engine will offer a high efficiency density power in line with the requirements of the mining industry. The ammonia mock-up engine will be on display at Liebherr’s main booth in the Atrium area.
