CNG Engine For Vehicles Specification Example for Fleet Maintenance: Heavy Duty
CNG Engine For Vehicles Specification Example for Fleet Maintenance: Heavy Duty
This is a worked specification for cng engine for vehicles in a heavy duty 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 heavy duty version exists because the duty cycle on fleet maintenance is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually a supplier who changed material without saying so.

Example specification
| Item | CNG Engine For Vehicles |
|---|---|
| Application | Fleet Maintenance |
| Version | Heavy Duty |
| Base material | Carbon Fibre Composite |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.05 mm |
| Finish | anodised |
| MOQ | 1,000 pieces per specification |
| Sampling | 10 working days, 5 days per revision |
| Compliance | ISO/TS 16949 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Carbon Fibre Composite, 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
- gravity casting
- anodising
- CNC machining
- electroplating
- assembly line testing
- surface grinding
Where this example applies
Programmes that run heavy duty most often specify this build for fleet maintenance. Related applications include delivery vans, assembly programmes, scooter fleets, city buses, three-wheelers.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 2.5 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
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 5 days once you have seen the first piece.
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the ISO/TS 16949-compliant build instead of a fresh interpretation.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
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.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



