reThink&reFuel | Liebherr

Open-technology approach

The reduction of global greenhouse gases is a significant challenge of our generation. Striving to reach net zero emissions in the future, Liebherr works on alternative and climate-friendly powertrain concepts.

Thereby, the Liebherr team pursues an open-technology approach. In the field of internal combustion, the focus of the research and development activities lies on multiple solutions, depending on the needs different fields of application will require in the future. Being a promising, carbon-free energy source, hydrogen is one of the options to power an internal combustion engine that builds a bridge to other alternate fuels.

Hydrogen is burned inside the zero CO2 emissions internal combustion engine; it is colorless, odorless and can be produced from water using renewable electricity. It holds a great potential in reaching the net zero emissions destination. Therefore, it is a key alternative fuel that Liebherr has started its research and development with.

Internal combustion engines (ICE) - the best solution in extreme operating conditions

We consider the internal combustion engine one of the most capable powertrains for high mechanical power under extreme operating conditions in the off-highway industry. In particular, heavy load conditions to which many heavy-duty vehicles and machines are exposed to, challenge the development of climate-friendly, reliable and efficient powertrain solutions. Internal combustion engines have met these challenges and requirements for decades, and will remain the primary powertrain in this sector – offering a sustainable solution to the market’s demands.

Combustion technology: sustainable and competitive

In regard to exhaust emissions, it is not so much about the combustion engine but the fuel that is used. Combustion engines will no longer be fueled solely by fossil diesel. To enable climate neutrality, fuels from renewable energies or sustainable sources must be used. These are for example, hydrogen, hydrogenated vegetable oil (HVO) or e-fuels. Hydrogenated vegetable oil (HVO) as drop-in fuel in the current internal combustion engines is as well a very efficient way to reduce significantly the carbon footprint of the heavy-duty off-road machines.

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Liebherr is convinced

that ICE will remain an important solution for heavy-duty and off-highway vehicles

Internal combustion engine: the most suitable technology for harsh environment

Today, the combustion engine is the most capable and – currently – most sustainable powertrain to drive applications under extreme operating conditions in the off-highway industry. Be it high or low humidity, high altitudes, dusty air, high shocks or vibration levels, the ICE shows numerous advantages:

Robustness to varying grades of H2
Increased robustness to high vibration levels
High tolerance to dust and dirt
Moderate effort and costs for engine conversion
Ease of integration of H2-engine into the existing engine installation space
Less complex cooling system

Podcast: Liebherr's path to hydrogen combustion

Discover more about the challenges in development of hydrogen combustion engine technology, its performance compared to diesel, its potential applications, the opportunities and the obstacles.

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Hydrogen fuel injection concepts

Common platform design for PFI and DI

gas-tight design (zero H2 leakage for highest safety)
good dry running capabilities (no lube oil)
hermetically separated solenoid drive concepts

Direct injection

direct actuated
platform designed for 12 g/s @ 30 bar
injector dimensions comparable to heavy-duty diesel injectors
flexible nozzle with exchangeable diffusor caps
top feed and side feed injector configuration
hermetic separated solenoid drive

Port fuel injection

direct actuated
platform designed for 12 g/s @ 15 bar
top feed and side feed injector configuration
hermetic separated solenoid drive

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PFI injects at pressures up to 15 bar into the air intake system. The uniform mixture homogenization in the intake manifold results in lower NOx emissions. Moreover, port fuel injectors work in less demanding operating conditions and as a consequence, time to market is much faster.

DI injects at pressures around 30 bar directly in the combustion chamber using a low-pressure process. The power density is similar to that of a diesel engine. DI is particularly well suited for applications with high demands on dynamics and power density within a limited installation space, such as mobile construction machinery.

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