Most hydrogen passenger cars to date have been fuel-cell electric vehicles, where hydrogen is stored onboard, converted into electricity, and used to drive electric motors. Suzuki’s prototype takes the older and more mechanically familiar route: keep the internal combustion engine architecture, but replace gasoline with hydrogen. That does not make the technology simple, but it does make it more understandable for automakers, suppliers and mechanics already built around combustion platforms.

AVL has been working on hydrogen engines for several years and previously promoted stoichiometric combustion, or λ=1 operation, as an alternative to conventional lean-burn hydrogen combustion. In this Suzuki project, the engine can run in both lean mode and stoichiometric mode using cooled exhaust gas recirculation. The cooled EGR system works as a combustion "moderator", lowering combustion temperatures and helping control nitrogen oxide emissions, which remain the main emissions challenge for hydrogen combustion.

The key technical point is that λ=1 operation delivers stronger performance. According to the project details, the hydrogen engine produces 100kW and 220Nm of torque in stoichiometric mode, around 10kW and 20Nm more than lean operation. For a compact hatchback such as the Swift, those numbers are not token demonstration figures. They are close to the performance expected from a modern turbocharged gasoline engine in the same general class.

The system uses direct hydrogen injection, dedicated hardware, advanced controls and thermal-management work designed to keep λ=1 operation stable. AVL and Suzuki also had to address condensate handling linked to cooled EGR, because water formation is part of the combustion process when hydrogen is burned. That is the sort of engineering detail that separates a press-release prototype from something that could eventually be developed for production.

Hydrogen combustion still produces no CO₂ at the tailpipe, but it is not emissions-free in the full technical sense. High combustion temperatures can create NOx, which is why cooled EGR, calibration and aftertreatment remain important. The advantage is that the base engine concept is familiar, the supply chain is partly reusable, and the driving experience can remain close to conventional combustion vehicles.

Suzuki’s choice of the Swift is also deliberate. Hydrogen demonstrations are often built around heavy trucks, buses, construction machines, ships or premium cars. The Swift is different: small, recognizable and widely associated with affordable mobility, especially through Maruti Suzuki in India. That makes the message more pointed. AVL and Suzuki are not just saying hydrogen combustion can work; they are saying it can be packaged into a compact vehicle class that normally lives or dies on cost.

Source:  Fuel Cells Works