Usually, switching to the mid-grade or premium-grade gasoline will remove the knock.

通常，切换到中等或以超值的汽油会删除敲。

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According to the EPA, a motorist who drives the Volt exclusively on electric power will pay an estimated 4 cents per mile in energy costs, while one who never recharges the battery and runs the car exclusively on gasoline (with premium grade required) will pay 9 cents per mile.

FORBES: Living With A Chevrolet Volt

It takes a double-size margin on premium gas, but the highest grade represents only 2% of its gasoline sales, versus 7% industrywide.

FORBES: Inconvenience