Bad bunkers damage engines

Poor ignition quality leads to excessive ignition delay causing fouling of valves, pistons, and turbo-chargers, resulting in a steady deterioration of performance during a voyage. There is also a very real risk of violent combustion that could rip the engine apart, says the Club.

While there is no widely accepted method for determining ignition quality of residual fuels, the Club says a relationship with density and viscosity has been empirically established. Ignition delay problems mostly concern medium-speed engines burning blended fuels of less than 220cSt and seem to be grouped in the CCAI value range of 850-890 (the higher the number, the longer the delay).

The Club is advising operators of sensitive engines to order fuels with a specified CCAI or set density and viscosity limits (which will control the CCAI).

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