WHY IS A SUMMER BLEND OF PETROL A THING?
It’s not just here in
California where different fuel blends exist. America has around 20
various blends of gasoline to meet state and federal guidelines. It
turns out that when state and federal laws differ, making something for
everyone gets complicated.
The reason for the variation in blends comes down to controlling VOC’s
(volatile organic compounds) relative to how likely they are to
evaporate when they get hot. The more VOCs, the more smog we see.
The Reid Vapor Measure (RVP) I mentioned on the podcast is the system
used to measure the volatility in gasoline in terms of PSI (Pounds Per
Square Inch). It measures the absolute vapor pressure exerted by a
liquid at 37.8 °C (100 °F). The higher the RVP, the easier to it is to
vaporize and the worse the effect on our environment. All gasoline
blends have to weigh in under normal atmospheric pressure – 14.7 PSI .
When that excessive heat of summer arrives, the RVP of gasoline has to
drop lower so it doesn’t boil off. The EPA, while it still exists,
mandates between 9.0 PSI and 7.8 PSI for summer grades. Because
different states reach different extremes of summer they have their own
blends.
(DriveTribe.com)
No comments:
Post a Comment