ALT-1 Why the Air Cooled Engine Disappeared
Evolving technologies via continuous research is perhaps the greatest treat to any existing technology all over the world.We have all had several experiences,and the wave is an ever growing trend.Those who know the story of the manual and the much more advanced electric typewriter will bear me witness.The story is not different for the air-cooled automotive engine,a machine that rely on the circulation of air directly over hot parts of an automotive engine to cool down.
Some clarifications are necessary here.In any automotive engine whatsoever,the air-cooled engine is just an integral part of the whole.Very versatile,the field of utilization of thistechnology is not only restricted to motor-bikes,cars and trucks,but also have made an impact in diesel engines,computer systems,as well as in aviation industry piston engines.In particular,the Volkswagen developed an air-cooled combustion engine solely for its VW kombi bus and VW Beetle.Both models operated with a 36-horsepower air-cooled engine.Other versions were created later,most especially the fuel injected type.Today,the aircraft industry still continue to patronize some variations of this engine.Therefore,apart from the aircraft industry,the air-cooled engine has virtually disappeared from the auto market for the following reasons:
1.Air-cooled engine cannot efficiently support larger application as is desired in the chemical industry.So,nearly all air-cooled engines are under 500 KW whereas large-liquid engines exceed 80 MW.In these industries,cooling towers and the atmosphere are not used as a heat sink.Rather,water-cooling of the engines is done via estuaries,coaster waters,and rivers.Thermal pollution of the air on a large scale, as could occur in an industry with air-cooled engine,would lead to global warming.
2.Air-cooled Volkswagen kombis are known for rapid wear in normal use and sometimes sudden failure when driven in hot weather.In the 70s and 80s,the VW kombis were the major commercial buses in western Nigeria.Ideally,the rear where the engine is found is supposed to be close while the bus is on the road or highway.With a hot weather most of the afternoons and the last quarter of each year,the rear engine door is always seen opened most of the time,perhaps,to allow most of the generated heat to flow away freely.Now,these models have disappeared almost entirely to pave way the more weather-suited water-cooled Toyota and Mitsubishi brands.
3.The emergence of a coolant based on propylene glycol which is liquid to -55 degrees centigrade,colder than is encountered by many engines;shrinks slightly when it crystallizes,thus avoiding engine damage;and has a service life of over 10,200 hours,essentially the lifetime of many engines,is another reason for the disappearance of the air-cooled engine.Ethlene glycol is another coolant in use in addition to some popular antifreeze,produced by mixing two or more coolants with more or less similar properties.
4.When automotive engine is air-cooled,more fuel is used and it is usually very difficult to achieve a low gas emission with the system,most especially with low grade fuels.Obnoxious gas such as carbon monoxide rent the surrounding air freely.This is a serious pollution issue and one which run counter to the green technology initiative.
5.The noise from an air-cooled automotive engine is much more higher than that from other engines,for example,water-cooled type.Noise is a pollutant and one which needs a medium.It is discharged alongside the heat produced by such engine.Compared,noise will travel faster in airmore than in water.Hence,water-cooled engine would be better favored in internal combustion engines.
6.Air-cooling is fraught with manufacturing expense and maintenance problems.Volkswagen in particular stopped the production of its 36/40 hp air-cooled engines in 1959.The reason was that even with research,the fuel injected 40 hp air-cooled engine didn't do well in the market.Hence,spare parts were no longer available to maintain the existing systems.Any car owner with VW models of that era must have survived with great difficulty.Hence,today,practically no air-cooled automotive engines are built.
7.In computer applications,overclocking and heat-handling are two problems emerging from the use of air-cooled system.It is not surprising then to see newer systems designed with a water-cooling system,consisting of a CPU water block,a water pump,and a heat exchanger.Its a growingtrend and it will not be a long time before a total switch to water-cooled or oil-cooled versions would be fully integrated.
Finally,it seems the era of air-cooling our auto engines has finally come to a stop,courtesy of the new,better and emerging technology that we have around now.Some of the reasons identified for the disappearance of the air-cooled engines include inability to build air-cooled engines exceeding 500 KW,air-cooled VW kombi buses wear rapidly during normal use and may experience engine failure in hot weather,emergence of a better and top-performing coolant known as propylene glycol,high gas emission,noisy engine,high manufacturing expense and maintenance problems, and overclocking and poor heat-handling in computer systems.In a way,technology has beaten the air-cooled engine to it!
