Corrosion Inhibitor
49. Petrol/ethanol blends can be more corrosive than petrol because of their conductive properties and tendency to attract water. They will be subject to the existing copper corrosion test for petrol. However, there are concerns particularly from the Japanese motor vehicle industry that petrol/ethanol blends (notably those above 3% ethanol) could cause corrosion of some aluminium fuel system components.
50. Corrosion inhibitor additives can provide protection against corrosion of a number of metals and are widely used in petrol/ethanol blends internationally. The inclusion of corrosion inhibitors tends to be industry practice rather than being provided for in specifications and on this basis some oil companies suggested that it was unnecessary to regulate their inclusion. However, to address motor industry concerns it is proposed that corrosion inhibitor be required to be added to all ethanol blended with petrol so as to minimise any risks. There is a range of corrosion inhibitors available and it is considered appropriate for industry to determine the most appropriate additive type.
51. The Ministry of Transport is co-ordinating a test programme to determine whether the use of a corrosion inhibitor could avoid the aluminium corrosion found in tests undertaken in Japan with petrol/ethanol blends higher than 3% ethanol.
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