Bosch hydrogen Nettuno engine is more powerful than the petrol Maserati V6

If the internal-combustion engine still has further chapters to write, they may be written without a single drop of petrol. That is the prospect Bosch is investigating by using hydrogen as a fuel.

Toyota has been the most visible advocate of this technology, but it is far from alone. Bosch is also pursuing it, choosing an unconventional platform to demonstrate just how far the approach can go.

The basis is Maserati’s Nettuno: the 3.0-litre twin-turbo V6 introduced in the MC20, featuring a pre-chamber combustion system. This Formula 1-derived technology was designed to improve combustion efficiency.

Bosch Motorsport has adapted the Nettuno to run on hydrogen, and the early results are especially noteworthy: this version already exceeds the power and torque figures of the petrol Nettuno used in the Maserati MCPURA.

More powerful than the petrol Nettuno

The engine has been fitted to the Ligier JS2 RH2, a prototype jointly developed by Bosch Engineering, Ligier Automotive and Maserati. The project began in 2021, while its first demonstrator appeared at the 24 Hours of Le Mans in 2023.

The concept has continued to develop ever since. The current iteration retains elements from the original Nettuno, including both cylinder heads and the turbochargers, while gaining several changes that allow it to burn hydrogen.

Its pistons have been redesigned, with their new shape making it possible to lower the compression ratio. The ignition system and engine control unit have also been revised.

Perhaps the most significant alteration, however, concerns fuelling. The production Nettuno combines direct and indirect petrol injection. In this hydrogen engine, Bosch uses direct injection only, through its new HIDI LCV injectors.

The outcome is approximately 480 kW, equivalent to 653 hp, and 880 Nm. By comparison, the same petrol-powered 3.0-litre V6 in the Maserati MCPURA delivers 630 hp and 720 Nm.

More significant than the outright figures is the durability shown so far. Bosch says that the Ligier JS2 RH2 and its engine have now covered almost 8,000 km of circuit testing in varied weather conditions, without technical issues.

It remains a combustion engine

An important distinction needs to be made. This is not an electric car powered by a fuel cell, such as the Toyota Mirai. Hydrogen is fed directly into the engine and burned inside the cylinders, in the same way that petrol is used in a conventional engine.

The benefit is that hydrogen contains no carbon, meaning its combustion does not directly generate CO₂ from the fuel itself. That does not mean the exhaust is entirely emissions-free. High combustion temperatures can create nitrogen oxides (NOₓ), which is why controlling the combustion process remains essential.

The source of the hydrogen itself is another decisive factor. For carbon-emissions reductions to make sense from an overall perspective, it must be produced using low-carbon energy sources, ideally renewable ones.

Bosch does not intend to replace electric vehicles

Bosch does not see the hydrogen engine as a universal replacement for battery-electric vehicles or fuel-cell systems. Instead, it regards it as another option for products in which, in its words, robustness, high power and rapid refuelling are especially important.

For now, the hydrogen Nettuno engine remains limited to the prototype world. Ligier itself has nevertheless acknowledged that the project could develop in several directions, including a track-day car combining Maserati technology with Bosch hydrogen systems.