Future Directions for the Internal Combustion Engine and How It Has Af Essay Example
The internal combustion engine has become an integral part of the lives of every person on earth. They're the devices that have allowed us to cross continents reliably, generate electricity in remote areas and fly around the world in a matter of hours. All these engines do is burn fuel and convert its energy into work. It's these heat engines that have really changed the world. However the convenience they bring has come at a great cost. The major problem with the internal combustion engine is the environmental damage it has caused. It is only now we are beginning to realise the full extent of this damage. In the mid-seventies basic steps were taken to reduce the pollution caused by cars, which of course at their heart is an internal combustion engine. The first and most obvious source of pollution from cars is the Exhaust pipe. Exhaust emissions contain carbon monoxide, unburned hydrocarbons and oxides of nitrogen. Also a small amount of solid matter, or particulates, is emitted in the form of lead from the tetraethyl lead used in fuel to increase its octane rating. It was found that these pollutants were having an adverse effect on the environment and in extreme cases were actually causing visible smog.' But exhaust emissions in pre-70's cars were only accounting for 55% of automotive air pollutants. Another major source was emissions of hydrocarbons from the engine's crankcase. They occurred because during combustion there is a small amount of gas Blow-By' past the rings, consisting mainly of unburned fuel. This would enter the crankcase and it would then be simply vented into the atmosphere. One of the earliest emission control requirements was to prevent this by using Positive Crankcase Ventilation' or P.C.V. This is where this unburned fuel would be routed into the inlet manifold for burning. The last form of pollutant that was causing problems was fuel evaporation. This is where fuel would evaporate and then would be allowed to escape through a vented