Alpine has unveiled the Alpenglow Hy6, which features a bespoke 3.5-liter V6 hydrogen engine with 740hp and 770Nm. The concept has been designed as a genuine race car based on an LMP3 carbon chassis.
The new Hy6 V6 was developed by the Alpine teams at Viry-Châtillon for use with hydrogen. It started its development two years ago, overcoming considerable engineering challenges associated with hydrogen combustion. Oreca is the technical partner that collaborated with Alpine on the project.
The engine is a 3.5-liter V6 open at 100° and it uses two turbochargers. Construction is from a solid aluminum block with a dry sump. It features a crankshaft with crankpins offset by 20° and cylinder heads made from cast aluminum with an optimized cooling circuit.
Valve timing is ensured by four chain-driven overhead camshafts and four four valves per cylinder controlled by finger cogs. By design, it is a ‘super-square’ engine with a 95mm bore and 82.3mm stroke, which is advantageous for high revs. The Inconel exhaust has been specially tuned for sound and revs all the way to 9,000rpm.
The engine develops it peak power 740bhp at 7,600rpm, corresponding to an impressive specific power of 211bhp/l for a top speed of over 330km/h. A centrifugal clutch and an Xtrac sequential gearbox complete the powertrain setup of the Hy6 engine. Alpine says that although the engine was designed for racing, it could be transposed to series production.
The combustion chamber has been designed to use hydrogen (more precisely, dihydrogen H2), favoring turbulent movements to ensure that the mixture is homogeneous before the spark. It is a crucial point as hydrogen ignites over a wide range of richness, which makes it prone to generating abnormal combustions: pre-ignition (spontaneous auto-ignition before the spark plug sparks, producing extreme pressure levels); or knocking, which generates auto-ignition and shock waves.
There are three tanks, located in the sidepods to store hydrogen in gaseous form (2.1kg each) under high pressure (700 bar). A pressure regulator reduces the pressure from 700 bar to 200 bar before dropping to the pressure required for direct injection into the combustion chamber.
Bruno Famin, VP Alpine Motorsports, said, “A solution for continuing to cultivate the passion for motor racing using a very noble V6 with remarkable specific power and a sound to thrill drivers and spectators with its maximum revs at 9,000rpm. The Alpenglow Hy6 concept is the perfect example of what is possible to achieve the essential step of reducing carbon emissions in motorsport.”
Alpine Racing says it is paying attention to changes in competition regulations and notes the plan for the ACO and the FIA to authorize the participation of hydrogen-powered cars from the 2028 24 Hours of Le Mans onwards.