ASTM to try another cetane index requirement via 'four-variable equation'

Diesel Fuel News, Oct 28, 2002

Having lost by one vote an attempt to require a 42.5 cetane index as an alternative to the 40 cetane number minimum (see Diesel Fuel News 6/24/02, p1), an ASTM cetane task force now proposes a "four-variable equation" to calculate a minimum cetane index. Engine makers are pushing refiners to boost cetane to avoid customer complaints about poor startability and white-smoke emissions.

This means some new revised calculation must be created, as a variation of today's ASTM D4737 method. D4737 method might have to be revised again once ULSD becomes the typical diesel fuel, the cetane task group says. It's uncertain whether the newly-proposed "four-variable equation" will result in something like a 42.5 cetane index requirement, as each candidate fuel will have a different distillation and gravity baseline.