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Electrical Engineering and Technology |Электротехника и электротехнологии

LESSON 9

Read the text: Ethanol and Methanol as Biofuels for Internal Combustion Engines in Motor Vehicles

 Ethanol (ethyl alcohol) and Methanol (methyl alcohol aka wood alcohol)can be used to fuel internal combustion motor vehicles, either as sole fuels or, more usually, when mixed with petrol (gasoline). As a warning, in case you think these alcohols are a cheap way of fuelling your cocktail cabinet, note that this ethanol is of a dangerously high proof and contains additives which make it poisonous (it is referred to as denatured alcohol). Methanol is well known to be a dangerous poison in its own right.

Most contemporary petrol cars will run on E10, a 10% mixture of ethanol to petrol, although warranties may state that a mix of 5% is the maximum allowed. Many major car manufacturers have developed cars which run on fuels containing higher proportions of alcohol, typically E85. Ethanol has some properties which are different from petrol; for example, in car engines, it has a higher octane rating, is more corrosive and abrasive, cleans the old deposits away (hence fuel filters, in converted vehicles, may need changing after a short time, initially), may create minor flow problems and can make starting more difficult. The national distribution network will also require modifications to some of its components, mainly because of the corrosive properties of alcohol and its ability to mix with water.

In the UK, in 2005, tax concessions for ethanol encouraged a minor shift and a 5% ethanol mixture entered the retail market. A firm called Greenenergypioneered this and Tesco have been reported as the retailers (mainly in SE England), the ethanol source being Brazilian sugar cane. The real motivation may be cost (although the reduction in price to the UK customer is small) but even so that is no bad thing. In 2006 another supermarket, Morrisons, started selling E85 bio-ethanol in East Anglia. The 5% mix can be used in most petrol vehicles but the 85% mix is limited to a very small number of current vehicles. It is hoped that the trend continues with a significant expansion of the use of bio-ethanol in the UK, and other sources will be created. The estimated energy densities for ethanol and methanol.

When compared to diesel, the energy densities are about 56% and 46% respectively, when compared with petrol (gasoline) the ratios are about 64% and 53%.

The design and adjustment of a Flexible Fuel Vehicle (an FFV will run on petrol and ethanol) must take these differences into account although the basic technology is not necessarily more advanced. Of course, if you don't have an abundance of suitable filling stations around the country then you can't expect the car manufacturers to supply the cars. Brazil is a country which well known for using alcohol-based fuels but there are others too. It appears that in the USA, farmers can brew their own licensed supplies.

1. Match the left part with the right:

2. Complete the sentences with the suggested words:

hoped   most   other   small

The 5% mix can be used in (1)_____ petrol vehicles but the 85% mix is limited to a very (2)_____ number of current vehicles. It is (3)_____ that the trend continues with a significant expansion of the use of bio-ethanol in the UK, and (4)_____ sources will be created.