Ethanol Use in Older Car Engines
Ethanol can be produced from crops for use as a primary fuel or blended with gasoline to run our modern car internal combustion engines, using blends from 10% to 100% ethanol.
However many older car engines have plastic and rubber components which can become brittle over the engine life. These components are susceptible to alcohol and can disintegrate when exposed to alcohol, causing leaks and blocking filters and fuel systems.
Also, years of accumulated dirt and sediment will have built up inside engine components, should this be washed off by the ethanol it will contaminate the engine oil and block filters eventually leading to engine seizure.
Along with this older engines will require quite significant modifications, and as we will discover ethanol, having 34% less energy per unit volume also offsets the benefits of using ethanol in the older engines. If ethanol is to be used in older engines it should therefore be restricted to lower blends such as E10.
Modifications required to the older internal combustion car engines
Various engine parts should be replaced before using ethanol mixed with gasoline. These include any plastic or rubber fuel components such as gaskets and seals, fuel/oil filters, and fuel spill pipes. Fuel tanks, filler pipe and fuel supply lines should also have a professional inspection for corrosion.
- Combustion air/gas or exhaust gas ratio sensors
Sensors are required to be fitted in the fuel and/or exhaust systems which analyze the gas/air ratios. This info is then fed to an on-board computer that adjusts the air/fuel ratio to ensure that optimum stoichiometric conditions are maintained.
Ignition timing will be required to be adjusted to prevent engine ‘knock’.
The higher octane rating of ethanol enables the compression ratio to be increased; raising the engine thermal efficiency. However it is quite a major operation to strip an engine and fit high compression pistons, so payback period would probably prohibit this alteration to the older car engine.