Following a concept world premiere in 2022 and a track demo at Le Mans a couple months ago, the Alpine Alpenglow is back, this time serving as a spectacular highlight of the 2024 Paris Motor Show. Alpine has equipped the latest Alpenglow with an all-new "Hy6" twin-turbo V6 engine developed from the ground up to run on hydrogen. The Hy6 doubles the power of the last Alpenglow so the new car not only looks like an extreme track-only supercar, it performs and sounds like one, too.
Alpine originally revealed the Alpenglow at the 2022 Paris Motor Show as a blueprint for its more sustainable sporting future. The concept appeared loosely derived from the extreme styling of the student-crafted A4810 Alpine had shown earlier that year, and came to Paris with the promise of a hydrogen-engine-based drive system of undisclosed size and layout.
The concept continued along as a stunning but mysterious piece of event jewelry right up until this past May, when Alpine officially turned concept car into "rolling laboratory" for a dynamic track debut at the 6 Hours of Spa-Francorchamps and, a month later, Le Mans. Ahead of those demonstration runs, the French automaker finally threw some tender red meat to the starved gearhead masses, confirming a 340-hp 2.0-liter turbo-four hydrogen combustion engine powering the wheels.
Okay, maybe that was more a serving of under-seasoned Beyond Meat plated for a feverishly carnivorous crowd. An H2.0 four-banger in a car that looks like it could be a personal spacecraft? That can't be right.
It was right, but Alpine did make clear that the developmental Hy4 engine was just a placeholder for a hydrogen six-cylinder still in the works. Now the time has come for the 4 to officially cede the cavity behind the two seats for the bigger, bolder Hy6, which instantly more than doubles power to 740 bhp.
The Hy6 isn't simply a preexisting gas engine converted to hydrogen like the Hy4 was. This is the first juicy fruits of Alpine's hydrogen combustion development program, a cutting-edge piece of machinery built from the ground up for optimal hydrogen combustion and a signal to the racing masses that there can be beautiful growling, asphalt-shaking life after petrol.
Exposed dramatically below a glass panel for its Paris debut, the new Hy6 starts life as a solid aluminum engine block with a dry sump. The cylinder banks are split into a 100° V below cast aluminum cylinder heads. With a 95-mm bore and 82.3-mm stroke, the cylinders have a "super square" form Alpine aims at better performance at high revs.
The Hy6's crankpins are offset by 20 degrees to help ensure smooth ignition, and valve timing is maintained by four chain-driven overhead camshafts and four valves per cylinder controlled by finger cogs. Displacement is 3.5 liters, and two turbochargers add to the fireworks.
The compressed hydrogen is stored in three regulation-grade composite tanks spread to the sides and rear of the cockpit in sealed and ventilated compartments. Each one is equipped with a rapid-release valve for expelling all hydrogen gas in the event of a fire. Before the hydrogen gets direct-injected into the combustion chamber, a pressure regulator reduces its pressure from the 700 bars it's stored at.
The chamber itself has been optimized around H2 combustion, enabling turbulent movements to create a homogenous mixture before sparking. Indirect water injection further optimizes the hydrogen and air mixture, helping to guard against abnormalities like knocking or pre-ignition.
There's no sense in making a modern track-bound combustion engine without a near-deafening grumble to announce its intentions. Alpine makes sure the Hy6 lets you feel the detonating hydrogen right down into your bones, tuning the Inconel exhaust to crescendo right up to the 9,000-rpm redline.
The Hy6 hits its max torque of 568 lb-ft (770 Nm) at 5,000 rpm and its 740-hp power peak at 7,600 rpm. The engine's 211 bhp/liter slightly tops the 205 we saw a year ago from another developmental hydrogen-combustion unit aimed at motorsport, AVL's 2.0-liter turbo four. All that H2-derived torque cycles through the Alpenglow's Xtrac sequential gearbox with assistance from a centrifugal clutch, pushing the car to an estimated top speed somewhere north of 205 mph (330 km/h).
Those numbers still fall a little short of the silent promises the Alpenglow conveys by way of its absolutely bonkers design, but the engine-car tandem still earns its "supercar" tag by serving as the testbed for what Alpine (and others) believe to be the future of motorsport in a low-carbon world.
"With the development of this brand new Hy6 V6 engine, we are demonstrating our commitment to hydrogen research, which could herald motorsport applications with high-performance levels," Alpine Motorsports VP Bruno Famin summed up. "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 9,000 rpm, the Alpenglow Hy6 concept is the perfect example of what is possible to achieve the essential step of reducing carbon emissions in motorsport."
Oh, and there's a pretty cool car surrounding all that engine, too ...
We've looked over the Alpenglow's curvaceously cavernous design several times in the past, and it has been gradually evolving, the end product of a collaborated waltz between design and engineering teams striving to compromise on the ultimate balance of optimized aerodynamics, precise weight distribution and buzz-making styling.
The new iteration sees only a few design modifications as compared to the car we looked over in April, but those few make a big visual impact. The rear of the car looks downright deadly after the addition of a razor-sharp central fin slicing the aforementioned transparent engine cover in half and two side blades capping the ends of the big wing, which itself has been raised higher. Below those small fang-blades, each haunch floats independently over its respective wheel, the body panel previously connecting them deleted to save weight.
Staying at the rear, look carefully at the interior of the icy light blades, and you can see the tall, ultra-slim exhaust tips that Alpine says breathe water vapor emitted by the H2 power plant onto the transparent wing, resulting in an even frostier look to complement the "Specular Blue" carbon bodywork.
Up front, the Alpenglow Hy6 retains the menacing but intently focused glare of sparkler-like headlamps, but Alpine pokes in a new set of nostrils between those eyes to better channel airflow.
While Alpine is excited to pursue hydrogen combustion's potential in and possibly beyond motorsport, parent company Renault isn't turning its back on other clean-drive technologies. It continues to explore alternatives, including battery electrics and hydrogen fuel cells on its way toward a goal of carbon neutrality across Europe by 2040 and globally by 2050. All this will be on display during this week's Paris show.
Source: Alpine