VIASBreath of Certainty: How simulation shaped the future of breath alcohol devices validation

The envisioned validation system had to operate under realistic conditions, delivering a high volume of breath alcohol tests per day while maintaining critical parameters within tight tolerances. The law in Belgium, as defined in the Royal Decree, says that air and water must be delivered at exactly 34 °C. This is a legal requirement, and the way in which this is achieved is by using a novel multi-chamber alcohol release system combined with a closed-loop thermal circuit. The margin for error in this is ±0.2 °C.
The airflow also needed to be fully programmable, with dynamic flow profiles and a wide operating range. The combination of these thermal, fluidic and chemical requirements meant that it was essential to validate the design at an early stage. Without simulation, critical flaws could only emerge during prototyping or laboratory integration, causing delays, budget overruns or compliance risks.

CTRL Engineering tackled this challenge through a model-based systems engineering workflow, translating each subsystem into a simulation model that could predict real-world behaviour in advance of any hardware development. The alcohol release system was modelled to simulate concentration behaviour across a large number of test cycles. The results demonstrated that a stable output could be achieved over time, well within the defined tolerances.
In parallel, a thermal model was built to simulate how the heating loop would perform in bringing the system from ambient conditions to 34 °C using a 3 kW power source governed by PWM control. The model confirmed that this target temperature could be held within a ±0.1 °C range, enabling highly consistent test conditions. This level of stability is critical for a laboratory environment that operates under ISO 17025 accreditation, where measurement uncertainty and repeatability are essential design drivers.
Finally, the pneumatic system was analysed to evaluate how precisely the airflow could be controlled across dynamic ramp profiles using solenoid valves and flow controllers. All simulation results were combined into a financial assessment that linked technical decisions to ROI, helping support the investment case well before moving to the hardware stage.