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Alpine Alpenglow Hy4: Pistons, keep on turning

Alpine Alpenglow Hy4

Alpine have turned their concept into a functioning prototype which will test a new hydrogen combustion powertrain. Ken Pearson investigates.

Alpine has joined a small number of manufacturers investigating the viability of hydrogen combustion powertrains. Rather than being powered by a fuel cell which uses hydrogen to generate electricity to power an electric motor and in turn drive the wheels, hydrogen combustion drivetrains use converted piston engines that run similarly to how they would on petrol. They even sound virtually identical to a petrol engine, so are seen by some as a means of keeping the internal combustion engine in production while hitting decarbonisation targets that are being legislated globally.

If you think you’ve seen this car before, there’s a good chance that you have. Unveiled first at the Paris Motor Show in 2022, the Alpenglow had hydrogen combustion in mind from the start with the first iteration fitted with a British-made V8 from Gibson Technology, makers of engines for the LMP2 class of sportscar prototype. Now, two years on, the engine and chassis have been updated and there are plenty of hints being dropped about this car reaching production.

But first, let’s take a moment to look at the car; striking is one of the first words to come to mind when describing it. The central cockpit flanked by wide sills and a roof-mounted air intake, high nose and deep-set splitter, air channel cutouts and a dorsal fin falling down towards a large rear wing and even larger diffuser are all Le Mans Prototype staples, but these are mixed in with touches seen on Alpine’s A110 road car like the bi-level quad-light signature. There’s more than just a slight family resemblance between the Alpenglow and the A424 LMDh racer; the similarities are clear to see both outside and in.

Alpine A424
Alpine A424

The monocoque is based on that of a Ligier LMP3 racing car so the cabin is wide enough to accommodate two people, doubling the seat count of the original concept. Butterfly doors open to allow access to the seats which are fixed directly to the tub. The new Alpenglow has already been designed with UK drivers in mind, with the steering wheel being on the right and indeed correct side of the cabin.

As is to be expected for a prototype, the interior is sparsely appointed with just a row of shortcut buttons for the fuel system, interior lights, ECU and a kill switch. The steering wheel looks to have been taken straight out of the A424 racer, but my favourite interior feature is the illuminated red triangle that has a light strip attached to it. This goes from interior to exterior and stops halfway along the nose section, before reappearing on the upright bodywork underneath the Alpine badge.

So with a good mixture of outlandish exterior styling and race-bred interior features, you may be surprised to learn that the standout feature of this car is actually a 2.0 litre four-cylinder engine. However, unlike the last performance car that switched a V8 for a four-cylinder engine before being almost universally slammed for not having the engine that it used to have (I’ll let you figure out which car I’m talking about here), the pitchforks are at bay for the Alpenglow Hy4, owing to it retaining the combustion performance, sounds and sensations that we all know and love, but doing away with the carbon emissions that the powers that be despise.

Alpine Alpenglow Hy4
Alpine Alpenglow Hy4
Alpine Alpenglow Hy4

The engine develops 335 bhp, is connected to a sequential transmission, revs to 7,000 rpm and can push the car towards an estimated top speed of 170 mph - not bad. It draws its energy from three highly pressurised tanks that hold hydrogen gas at over 10,000 psi, or 700 times atmospheric pressure. Wow.

The three 55 litre tanks would hold enough petrol to take the car almost 1,000 miles but owing to the tanks holding gaseous hydrogen rather than liquid, the 6.3 kg payload is said to return a track range of 62 miles. It’s got to start somewhere, I suppose! After being held at 700 bar in the tanks, the hydrogen moves through pressure regulators that drop it down to 200 bar and finally 40 bar when it is injected into the cylinders. Water injection is utilised to reduce nitrogen oxide (NOx) emissions at the tailpipe too - more on that later.

The car made its public debut at this year’s FIA World Endurance Championship 6 Hours of Spa race and was due to complete some demonstration laps in front of the bumper crowd in Belgium, but electrical issues prevented the car from starting. Its mobile public debut will instead be at the 24 Hours of Le Mans, and the car will be tested extensively before the arrival of a new V6 engine that has been designed to be run on hydrogen from day one - but this time it will be using liquid hydrogen which will mean a longer range is attainable but storing it at sub-zero temperatures will be a challenge.

The demonstration runs at Le Mans will be key, as the Automobile Club de l’Ouest (ACO) - the organisers of the 24 Hours of Le Mans - have been working on hydrogen cars for a long time already, with the Mission H24 car being used to investigate how to use and refuel hydrogen fuel cells in endurance racing. A hydrogen-powered class has long been in the works for Le Mans and at the 2023 event, Toyota unveiled their GR H2 concept which also features a hydrogen combustion powertrain. There is no better testing ground than racing; hybrids weren’t cool until they took the form of LMP1 cars, and high-performance EV powertrains have come on leaps and bounds with Formula E.

Alpine Alpenglow Hy4

Let’s get back to the point though: if the original Alpenglow concept was a statement of intent, the running prototype Hy4 is a proof of concept, and it looks like the next stage is to make it viable for production which Alpine are already keen on doing with a liquid hydrogen V6 drivetrain. So could the future of the combustion engine be secured, and more importantly, is hydrogen the future of it?

Well, I’ve lost count of the number of times that I’ve been told that “hydrogen is the future” to which I typically say “yes, and it has been for the last 20 years while battery EVs have become the present.” I still stand by that, but a more detailed rundown of the battery vs hydrogen debate is a story for another time. Hydrogen combustion is something that Toyota have been working on for a few years now and the benefits for the driver include the familiar performance delivery and sound of the engine, coupled with quicker refuelling times than an electric car and significantly reduced emissions compared to a petrol or diesel engine.

It’s important to know that hydrogen combustion engines are not emission-free, with water vapour - which is a greenhouse gas - and NOx being produced, but according to Alpine this is at a level far below what a dinosaur liquid-powered engine could ever achieve. The benefit for the manufacturers is that all the R&D has already been done on piston engines, so the job is one of modifying rather than starting afresh with a yet-to-be-perfected powertrain like a fuel cell or an electric motor.

Alpine Alpenglow Hy4
Alpine Alpenglow Hy4

So hydrogen combustion offers a way to keep the sounds and driving characteristics of exceptional petrol engines going into the future while reducing what else goes into the atmosphere other than the noise. But there is already another way of reducing emissions in piston engines while also making them smell nicer; once the demonstration laps are completed by the Alpenglow Hy4 at this year's 24 Hours of Le Mans, 62 cars across three classes will fight it out for top honours in the biggest race in the world, all without burning a single drop of petrol.

Since 2022, the World Endurance Championship and European Le Mans Series have been using Total Excellium Racing 100 fuel which is made from byproducts of the wine-making industry. It smells fantastic and is said to reduce emissions by 65% compared to petrol. And of course, the other option is to go for a pure electric powertrain which reduces local emissions by 100% but increases them along the production process. Alpine is committed to this for its upcoming A290 hot hatch, A110 replacement and future midsize crossover, but to concurrently commit to extending the viability and feasibility of the powertrains that have got the brand to where it is today has got to be saluted.

So, to once again get back to the point which is the Alpine Aplenglow Hy4, the striking LMP-inspired car is testing the tech and the reaction of a piston-engined sports car of the future. It shows a commitment to the targets that have been set by regulators for cutting emissions but more importantly, it shows a commitment to the types of people who buy Alpine road cars and cheer on the race cars at Le Mans and around the world: the enthusiasts. Chapeau, Alpine.


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