I asked the same question to chat GPT .
Is 92 RON petrol suitable for a 16:1 compression ratio engine (as in Deepal S05 REEV)?
Yes — it is suitable, because of how a REEV engine works.
Although 16:1 compression ratio is very high for a normal gasoline engine, REEV (Range-Extended Electric Vehicle) engines are different:
- Engine does NOT directly drive the wheels
The engine only works as a generator at controlled RPM.
It stays in an optimal, stable operating range where knocking risk is minimized.
- REEV engines are specially tuned for high compression
They use Atkinson/Miller cycle–style tuning, EGR, precise ignition control, and knock sensors.
These technologies allow the engine to safely run on lower-octane fuel.
- China also uses mostly 92 RON petrol
The Deepal S05 (and similar range-extender engines in China) are designed to run on 92 RON, the same as Pakistan’s regular petrol.
Manufacturers tune these engines specifically for 92 because it is the most common fuel in China.
- High compression ≠ high octane requirement in REEV
In traditional cars:
16:1 compression needs High-octane fuel (95/98).
But in REEV:
Effective compression is reduced by late intake valve closing (Miller cycle).
Therefore, 92 RON is safe and intended.
Conclusion
Using 92 RON petrol in the Deepal S05 REEV is fine, safe, and recommended.
The vehicle is designed to operate efficiently on 92 despite the high compression ratio.
