Editor's Comment: Diesel is here to stay
By Chris Sleight03 August 2012
Internal combustion engines have been around for some 150 years. They are undoubtedly one of the most significant inventions in human history, but they are not without their problems. The metal-on-metal movement means they need constant lubrication, they have lots of moving parts, get very hot, are heavy, fuel is getting more scarce and more expensive, and new laws to cut harmful exhaust emissions mean a lot of expensive technology needs to be used to reduce pollutants.
But for all their drawbacks, they are wildly successful. There are billions of engines in use around the world today in cars, trains and ships, as well as in industrial applications and off-road equipment like construction machines. Diesel engines remain the overwhelmingly popular choice to power equipment in this industry.
As Gwenne Henricks, president of Perkins explains in this month's interview, that is because diesel engines have a lot going for them. They are power-dense, meaning you get a lot of energy out of a small package, the fuel is easily portable, and a reasonably manageable quantity will keep an engine running for a long time.
The popularity and ubiquity of combustion engines is testament to their fitness for purpose, but I tend to feel that part of that is because there has never been a viable alternative. Look at the car industry - until very recently, electric-powered vehicles were a bad joke. The early electric cars were slow, had very little range and took far too long to recharge. But now cutting edge all-electric vehicles like the Tesla Roadster show the issues of range and speed are not insurmountable.
All-electric equipment is of course nothing new in the construction sector when it comes to static (or relatively static applications) - tower cranes or crushers for example. In addition to mains-powered machines, visitors to this year's Intermat exhibition may have seen some of the battery-powered compact excavators that could come on to the market in future years.
It is a sign that the industry is interested in other power sources, but a problem remains that it is difficult to get enough batteries on board a 1.5 tonne mini excavator to keep it running for a full day - something that is not an issue with a diesel machine. Needless to say a battery powered 40 ton ADT is a long, long way away!
So as Ms Henricks says, there is no doubt that diesel engines will be around for a long time to come - it will take a real quantum leap in battery power to replace them. But she also makes the point that there is a lot of technology out there that could go a long way to enhancing what can be done, from diesel-electric systems to hybrids, and through the use of alternative fuels, perhaps the most promising of which at the moment is natural gas.
But one of the issues is that unlike cars, which are all more or less the same and are used in similar ways, different construction machines have very different characteristics, and so will be need different solutions. The relatively small volumes in the construction industry will also mean it will take a long time to get economies of scale and more competitive prices.
So alternatives to the diesel engine are on the way, but it will be an evolution, not a revolution.