Diesel Fuel Enhancer Specification Example for City Buses: Long Life Version
Diesel Fuel Enhancer Specification Example for City Buses: Long Life Version
This is a worked specification for diesel fuel enhancer in a long life version programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The long life version version exists because the duty cycle on city buses is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually lead time that slipped twice before bulk started.

Example specification
| Item | Diesel Fuel Enhancer |
|---|---|
| Application | City Buses |
| Version | Long Life Version |
| Base material | Polypropylene |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.05 mm |
| Finish | as machined |
| MOQ | 3,000 pieces per specification |
| Sampling | 10 working days, 3 days per revision |
| Compliance | TUV |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Polypropylene, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- precision stamping
- CNC machining
- die casting
- laser cutting
- robot welding
- heat treatment
Where this example applies
Programmes that run long life version most often specify this build for city buses. Related applications include long-haul trucks, emergency vehicles, camper conversions, agricultural trailers, dealership service.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 3 days once you have seen the first piece.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 3000 pieces per line.
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
Ask for the current catalogue and the specification sheet for this line.



