4X4 PROFESSOR
Ever wonder how a turbo works?
WHERE DO TURBOS COME FROM?
As with most smart vehicle technology, we have the German speakers of the world to thank for turbochargers. In 1877 a German engineer named Nikolaus Otto patented the modern internal combustion engine. His colleagues, Gottlieb Daimler and Wilhelm Maybach, actually had their own designs, and in 1882 they released their own version (there was a bit of tension in the air, almost like an episode of Egoli). In 1885 Daimler released a gear-driven pump to force extra air into the engine. But it was only in 1925 that a Swiss engineer, Albert Büchi, patented the first version of the modern turbocharger – and for a diesel engine of all things. With this invention he could make a diesel engine up to 40% more effective. While Büchi’s design has been perfected over the years, it still remains the basis for all turbocharged engines.
HOW DOES IT WORK?
An engine develops power by igniting a mixture of fuel and oxygen in its cylinders. And the more of this mixture you can get in the cylinders, the better. Thus, if you can force more air (together with extra fuel) into the cylinders than is possible under normal circumstances, the engine will develop more power. And that’s where a turbocharger comes into the picture, because it uses a vehicle’s exhaust gases to drive a turbine. This turbine is in turn connected to a compressor turbine by an axle, which sucks in air from the atmosphere, compresses it and sends it to the cylinders, thus generating extra performance.
WHAT ARE THE BENEFITS?
One benefit is that a smaller engine can develop a lot more power and torque than what is possible without a turbo. Manufacturers are also able to use smaller and lighter engines to provide the same perfor- mance as a much larger engine would. Another advantage is that a turbocharger can negate the adverse effects that high altitude have on engine performance. Where normal engines at Gauteng’s height above sea level would normally lose up to 17% percent of their power, a typical turbo-engine will only lose about 3%.
WHAT ARE THE CONS?
Turbo-engines are a bit more complex than normally-aspirated engines because of, amongst other things, the extra plumbing involved. Turbochargers also become very warm, due to the hot exhaust gases used to propel them. And there’s the fact that it’s not unusual for them to spin at 200 000 r/min! Luckily, modern turbo technology has come so far that you don’t often hear of turbos blowing up. Turbos also require a certain minimum engine speed necessary to allow the turbines to rotate fast enough – which is what causes the dreaded “turbo lag”. Modern turbos have much less turbo-lag, but a powerful petrol engine without a turbo doesn’t have the same problem.
WHY A DOUBLE TURBO?
Because of this problem, lots of manufacturers use two smaller turbos instead of one large one. While large turbines can compress a huge volume of air, it takes them longer to rotate fast enough at lower speeds – resulting in turbo lag. Smaller turbines have much less inertia, and if you combine two of them, they can provide air at the right pressure to the engine faster – without reducing the volume of air supplied.
WHAT IS AN INTERCOOLER?
You’ve probably heard about an intercooler. It’s basically a type of small radiator through which the air from the turbo moves to the engine. Because cool air is denser – and thus more oxygen-rich – an intercooler helps improve performance. Not all turbochargers have intercoolers, but these days they are very common.
WHAT IS A KOMPRESSOR?
A kompressor (German for supercharger) does the same job as a turbo, but goes about it in a different way. Where a turbocharger’s turbines are propelled by the engine’s exhaust gases, a kompressor is driven by belt connected to a pulley on the engine, similar to that of an alternator. The difference is that a turbocharger has some turbo lag as a result, but doesn’t use any engine power, while a kompressor immediately provides extra power, but at a price, because it saps some engine power to drive the kompressor.