Toyota's Liquid Hydrogen: The TR LH2 Racing Prototype Hits the Track at Le Mans, but How Does It Work?

Next week, Toyota will bring the TR LH2 Racing prototype, powered by liquid hydrogen, to the Circuit de la Sarthe, where the 94th edition of the 24 Hours of Le Mans will take place.

Based on the same chassis as the hybrid Hypercar TR010 HYBRID that will participate regularly, the hydrogen vehicle we will see in this public demonstration should not be confused with "normal" fuel cell vehicles. In this prototype, just like in previous models that initiated the project, Toyota does not create electricity from fuel cells to power an electric motor, but uses hydrogen as the fuel for an internal combustion engine. The TR LH2 Racing takes this concept to the extreme by using liquid hydrogen instead of gas.

Liquid hydrogen offers the advantage of compression, allowing much more energy to be stored in the same space, but it also introduces extreme challenges for designers and engineers. Hydrogen in this state drops to a temperature of -253°C and must remain at that temperature.

The tank is therefore a marvel of cryogenic engineering with a double vacuum chamber to avoid any thermal exchange and the boil-off of the gas. However, the internal combustion engine cannot burn hydrogen if it is too cold, so the gas follows a meticulously studied path. A special pump developed by Toyota, capable of operating at temperatures close to absolute zero, extracts the liquid hydrogen from the tank while keeping it stable. Before entering the cylinders, the hydrogen passes through a heat exchanger that uses the heat from the engine to evaporate it and bring it to an optimal temperature for combustion. The gaseous hydrogen is then injected at high pressure directly into the combustion chamber. Here, traditional spark plugs create the spark that generates the expansion, moving the pistons in the same way as a gasoline engine.

We know that hydrogen produces only water as a waste product, but this engine, utilizing atmospheric air like any internal combustion engine, also takes in nitrogen, abundant in the air, and therefore, due to the high temperatures, generates nitrogen oxides, the infamous NOx. Being harmful compounds, Toyota employs advanced exhaust gas after-treatment systems to reduce them.

For those attending the event, prior to the demonstration laps, the TR LH2 racing prototype will be on display for fans in the Hydrogen Village, a hydrogen technology showcase that includes information and vehicles, demonstrating Toyota's commitment to a carbon-neutral impact society. The Hydrogen Village will be officially inaugurated on Wednesday, June 10.