Crimson Racing Wiki

Pressurized CO2 Tank

Subteam: PowertrainSubsystem: ShiftingAssembly: Shifting AssemblyCars: CR22, CR25, CR26I

Purpose

Store the working gas for the pneumatic shifting and clutch system.

Function

A 1000 g capacity CO2 bottle. CO2 has been the architecture of choice since the team first implemented automatic shifting.

Design Process

No part-specific design process is documented. The Shifting subsystem design process applies: 1. Route every line and fitting in SolidWorks. Lines cannot be within 1 in of the engine casing or 3 in of the exhaust; bend radius is 4 in. 2. Size the cylinder bore and line inner diameter with full calculations rather than by picking a catalogue part. 3. Fit the linear potentiometer and set the position bounds that define a completed shift. 4. Tune the preload duration and the torque reduction window on track. 5. Measure the result. CR26I averaged 65 ms cut time across endurance closed loop against 85 ms open loop; across 180 upshifts that is 9 seconds under power cut instead of 15.3 seconds.

Design Constraints

The tank must be mounted in the only orientation allowed for CO2 bottles. Mounting it any other way is what used to cause lines to burst.

Manufacturing Process

Welded from sheet or tube.

Full Material List

Aluminium.

Reoccuring issues

Refills used to be an ordeal; the team can now fill in house.

Properties

1000 g capacity, regulated to roughly 100-110 psi system pressure. Quantity per car, as costed: 1

Still to document

Nothing in CrimsonStorage covers these yet.