How 3D printing is rewriting hydrogen intake design

The rise of hydrogen propulsion places unprecedented demands on materials, sealing, thermal stability and system integration. Lightweight structures must withstand pressure, vibration and thermal cycling while maintaining absolute dimensional integrity

Against this backdrop, Alpine’s Alpenglow Hy6 offers a compelling case study of how advanced composites and hybrid manufacturing can redefine what is technically feasible in hydrogen powertrain design.

At the centre of the project is a fully monolithic intake plenum and manifold system 3D printed by CRP Technology on behalf of Alpine. Manufactured in carbon fibre–reinforced thermoplastic Windform SP using Selective Laser Sintering (SLS) and refined through CNC machining, the system demonstrates how additive manufacturing can move beyond prototyping into structurally critical engine components.

THE ENGINEERING CHALLENGE BEHIND HYDROGEN COMBUSTION

The Alpenglow Hy6 embodies Alpine’s vision of hydrogen-powered performance. As in any hydrogen combustion architecture, the intake system quickly emerged as a critical bottleneck; it must handle elevated pressures, temperature gradients and continuous vibration while preserving perfect sealing.

In the initial setup, the plenum and manifolds were already 3D printed, but aluminium flanges were bonded to the parts to interface with the engine. During bench testing, Alpine engineers identified leakage and sealing issues at the glued joints, driven by the different thermal expansion coefficients of aluminium and the polymer composite, further aggravated by vibration and high thermal loads.

FROM MULTIMATERIAL ASSEMBLY TO MONOLITHIC ARCHITECTURE

To address the challenge, Alpine engaged CRP Technology for a fast, robust solution capable of maintaining structural integrity under extreme conditions. CRP – also the manufacturer of the original components – proposed a fully monolithic intake system produced again by SLS, using a single material throughout. Windform SP was selected once more for its high stiffness, mechanical strength and thermal resistance – key properties that made a monolithic architecture both feasible and reliable.

Only minor design adjustments were needed. The final system comprises three single-body components – one plenum and two manifolds – with flanges integrated directly into the Windform SP structure, eliminating aluminium parts. This redesign simplified assembly and ensured uniform material behaviour, delivering dimensional stability and consistent sealing performance even under high turbocharged pressure.

“Transforming the intake into a fully monolithic structure allowed us to stabilise the entire air-path architecture and remove the weak points inherent in multimaterial assemblies,” explains Franco Cevolini, CEO and CTO of CRP Technology and CRP Meccanica. “With Windform SP and SLS, engineers can design around the behaviour of a single, predictable material – an essential advantage when dealing with the pressure pulses and thermal gradients of a hydrogen engine.”

HYBRID MANUFACTURING: ADDITIVE MEETS SUBTRACTIVE

The project also highlights the role of hybrid manufacturing workflows in next-generation powertrains. After SLS manufacturing, the parts underwent vapor smoothing at CRP Technology, reducing surface porosity and improving the aerodynamic quality of internal channels, critical for optimising airflow. CRP Meccanica then carried out CNC finishing on the coupling interfaces, leveraging its high precision machining expertise within the CRP Group.

This additive-plus-subtractive workflow delivered tight dimensional accuracy and precise assembly fit, enabling the components to withstand repeated pressure cycles up to 5 bar during turbocharged operation. The result is a set of lightweight, geometrically complex components capable of operating reliably under the thermal and vibrational stresses typical of high-performance environments – without tooling, and with the agility needed for rapid iteration.

VALIDATION UNDER REAL CONDITIONS

The monolithic intake was first validated on the engine dyno, where it demonstrated excellent sealing and mechanical stability under demanding thermal and pressure cycles. It was then installed on the Alpenglow Hy6 for on-track testing, confirming durability, resistance to pressure and heat, and overall performance.

From a development standpoint, the elimination of tooling significantly shortened the design-to-part cycle. “For experimental hydrogen programmes, the ability to iterate quickly without manufacturing constraints is crucial,” notes Cevolini. “That flexibility translates directly into faster development and more robust engineering decisions.”

IMPLICATIONS FOR HYDROGEN AND E-POWERTRAINS

Although developed for a high-performance concept, the lessons extend well beyond motorsport. As manufacturers evaluate hydrogen within broader e-powertrain strategies, components must address thermal management, sealing, weight reduction and packaging efficiency.

Additive manufacturing with advanced composites enables design driven by function rather than manufacturing constraints. The geometric freedom of SLS allows channels, mounting features and reinforcements to be integrated directly into a single component, reducing assembly complexity and eliminating weak interfaces. Windform SP is central to this shift: its fibre-reinforced structure delivers a balanced combination of stiffness, strength and thermal resistance, while compatibility with vapor smoothing and CNC machining ensures that additively manufactured parts meet the tight tolerances required in powertrain systems.

Veronica Negrelli is at CRP Technology www.crptechnology.com