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 cap.
This was stopped by venting it, in most cases, to a charcoal canister where it would be stored to be burnt later in the combustion process. The Australia Design Rule 27A (ADR-27A) was introduced in July 1976. This was the first major emission control requirement in Australia. It addressed the issues of vehicle emissions and car manufactures were required to abide by it in order to reduce the emissions of their cars. The world is learning to a greater extent that vehicle pollution is a real problem and great advancements have been made in making the internal combustion engine an environmentally friendly and efficient machine.
Things such as E.F.I and catalytic converters are standard equipment on even the most mundane of new cars. The lives of old leaded fuel burning engines are being extended through the development of lead-free, high-octane fuel. These are necessary steps, but more needs to be done. I believe that the internal combustion engine fuelled by fossil fuels will remain the staple source of power for us for many years to come. However our finite supplies of fossil fuels mean we need to look at alternative sources of power for our vehicles. Even now we see designs for Hybrid’ vehicles where an electric motor and a low-emission engine work together to produce an efficient car that doesn’t have the problems of poor drivability that come with pure electric cars.
I have always been of the opinion that hydrogen will be the way of the future for the internal combustion engine. Hydrogen is plentiful; it can be extracted from water. When hydrogen is burnt all that is produced is water vapour, which hydrogen can be extracted from. It is such a good fuel I am amazed that more isn’t being done to develop it. I think a major factor in it not being developed is the public opinion of hydrogen.
When ever hydrogen is mentioned people instantly think of the Hindenberg disaster and they don’t like the idea of a tank of it sitting behind them in a car. I still remain confident that in my lifetime hydrogen will become the fuel of choice for car manufactures. Few advancements in technology have impacted us in the way the internal combustion engine has. Indeed a world without them would seem so foreign to us. Their problems are being gradually solved and new ideas are being developed so that the world can continue to take advantage of their motive power and still be kind to the environment.
I think we can agree that the internal combustion engine is a good thing when it’s powering the ambulance transporting you to a hospital to save your life, and a bad thing when it’s powering a B-1 bomber carrying bombs to kill people. Like every form of technology we choose how it’s used and we are the ones that are ultimately responsible for its effects.
Bibliography
- “Emission Control Systems, Service Manual Supplement” A Holden Publication – 1977
- “Coltrane’s Planes ; Automobiles – Engines That Turned The World” By Robbie Coltrane and John Binias A Channel Four Book – 1997
- “Car Crazy” (Television Program) A Discovery Channel Production -1999
