Hello to my fellow engineering apprentices, please strap on your seat-belts because TODAY I will drive you through a rough rise about the modifications needed to accommodate ethanol in motor vehicle.
Before I start, does anyone know some of its properties which differentiate itself with petrol? Yeps. They are the ones on the projector.#
Ethanol has a uniquely narrow vapourisation temperature, so an air heating device is needed for reliable starting below 13oC# such as Beru Corporation’s automatic heating control.# It consists of a power relay, a thermal switch and a timing relay.
Since the solubility of ethanol in petrol is limited at room temperature, phase separation may occur which may lead to the engine not being able to start at all. Luckily, it may be overcome by having a mixing pump in the tank.
Ethanol is also more polar than octane molecules (major component of petrol). At room temperatures, ethanol would be gases if they were not collapsed into liquids by hydrogen bonding. As a result, we can use emulsions of ethanol in petrol since such a technology and could utilize the vapourised ethanol.
#Ethanol has a high octane rating, thus the fuel will burn slower creating minimal engine knocking. High octane rating also allows higher compression ratio and different spark-timing for improved performance. # This can be done by machining valve relief into the piston face so it can be positioned down further into the engine for improved motor performance.
In addition, ethanol fuel has a lower enthalpy, so its engine output is reduced. Hence, tank size needs to be increase to avoid frequent refueling.
Ethanol’s density is only 60% of petrol which would slow down the speed of the fuel entering into the engine cylinder. This can be overcome by installing injection pump and larger carburetors to speed up the fuel’s delivery rate.
Due to wide range of ignition limits of ethanol, flame arrestors have been inserted in the filter neck and vent...