The fuel spray nozzle isn't a single part but a complex assembly of exquisitely small components. The primary nozzle fits precisely inside the secondary nozzle, with a tiny swirl chamber at the bottom that is held in place by a spring-loaded pusher bar. Every single dimension and surface finish is mission-critical. These microscopic details determine how the faces seal and, ultimately, how the fuel atomises inside the engine.

Our challenge was with the final hole needed to complete the primary orifice. We had to modify our initial tooling, which resulted in a slight defect. We've since received new, specialised tooling designed specifically for this task:

• An initial chamfer tool
• A pilot drill
• A final drill to create the minuscule 0.17 mm central hole for the primary nozzle.

With this new equipment, we've successfully completed the part. These primary nozzles are essential for a smooth and uniform engine startup, and now we are ready to begin full production.

We used an advanced optical scanning method to create a complete digital model of the components. This allows us to "see" inside the parts, measuring every critical fit, angle, and surface finish with incredible accuracy.

The scans confirmed that we are manufacturing the components to the required tolerances and hitting the surface finish targets needed for a perfect seal and optimal fluid dynamics. While we found a couple of very localised machining marks that we can refine in our process, the parts we have are good to go for the test rig.

This rig is essential for characterising the performance of each nozzle before it ever sees an engine. We now have a fully automated and data-rich environment:

• The gear pump and flow control valve are now under full computer PLC control, allowing us to simulate any flow condition.
• Live data acquisition from flow meters and pressure sensors on both sides of the nozzle lets us map its entire operating range.
• A laser-based visualisation system in the flow tank optically measures the spray's cone angle and the Sauter Mean Diameter (a key metric for the average fuel droplet size), giving us a complete picture of atomisation quality.

With the first set of precision nozzles complete and the test rig fully operational, we are ready to bring them together. The next step is to put these components through their paces and gather the critical data that will validate our design.