Full explanation
Practical consequences of low CN on Ukrainian farms: (a) smoke on startup at any temperature (real CN 51+ should ignite smokelessly above +5°C); (b) knock/detonation at 30–50% part loads (typical in ploughing with a small trailer); (c) elevated consumption 3–6% on the same operations; (d) accelerated Common Rail injector wear from incomplete combustion and soot deposits; (e) DPF clogging at 200–400 engine-hours instead of 600+ — which via dealer-lock becomes a UAH 25 000+ service event. How to verify: (1) request a quality passport with CN (bulk supplies from OKKO, WOG, SOCAR, KLO always include it); (2) Ukrmetrteststandard petrochemical labs in oblast capitals run the test at UAH 800–1 500, 3–5 days; (3) field cold-start test — if the diesel in the tank is genuine, at +5°C the tractor starts within 2–3 s without grey smoke. Source: energy-kb.ts `cetane_number` field + DSTU 7688:2015 Table 1.