We all know that fuel for cars is exhausting from the earth at an alarming rate. And the car makers are trying very hard to come up with alternate fuels for the future. But for the time being, they are also churning out new technologies to extract more out of the same amount of the fuel in a car. With even the F1 downsizing the engine size to a meagre 1.6L, the car companies are also expected to also do the same without losing out the performance figures.
One such technology that has been immensely successful in achieving this is called a turbocharger. It mainly constitutes a compressor which compresses the air that mixes with fuel for burning in the piston. To make it a little more easy, it forces more air and hence more fuel in the engine and that, even a 10 year old can say, means better power and torque.
In the real world, it means that a smaller capacity engine can churn out greater amount of power with a small increase in fuel efficiency as compared to a non-turbocharged counterpart. The turbine that drives the compressor is run by the exhaust gases emitted by the engine and to harness this energy, turbos are generally mounted near the exhaust manifold of the engine.
The use of turbochargers in petrol engines has only recently gained momentum as before that, turbos were mostly used in diesel engines. This has been possible mainly due to the advance of technologies that can now make it possible to actually increase the efficiency of the petrol engine using a turbo. Most of the car companies nowadays are investing heavily on this tech as many consider this the future of automotive industry.
The turbocharger (or a turbo, as it is usually called) has a sibling too. It’s called a supercharger.
The difference? The turbine that drives the compressor in a supercharger is powered by the engine’s fan belt as opposed to exhaust gases in a turbo. Many of you must now be thinking whether that makes the turbocharger better of the two. Well…Yes and no.
Yes, because it does not put any mechanical load on the engine and is also more efficient as it uses the waste gases to power itself. But a major disadvantage is the turbo lag. The turbocharger relies totally on the exhaust gas pressure to create the boost. At lower rpms, the exhaust pressure isn’t enough to spool the turbo. That means it cannot create much of a boost in such a situation. This situation can be overcome by using a smaller turbo which will spool up faster but provides less power boost. In comparison, the supercharger is better off here as it can provide an instant boost.
To get an idea of how much the turbo increases an engine’s power, let’s take a look at the Honda’s recently launched 1.5L turbo engine. It produces a healthy 201bhp. Compare that with the Honda City’s 1.5L engine. It does not have a turbo and the result? A full 84bhp less!
Turbo is usually used in vehicles that, most of the time, run on intermediate to high rpm so that the effect of the turbo can be maximized.
Types of Turbochargers
- Twin Turbo/Bi-turbo: Has 2 turbochargers which may or may not be of the same size. They are used either in series or in parallel.
- Twin scroll: It has 2 exhaust gas inlets that power the same turbo. This greatly reduces the turbo lag.
- Variable Geometry Turbo: This type has vanes that can change the size of the turbo according to the flow of the exhaust pressure to provide boost across the rev range.
Here is a list of all the petrol turbocharged engines by the major automobile manufacturers.
- Duratec Sci 1.1L
- Duratec RS 2.0L
- EcoBoost Range which includes the following
– 1.0L I-3
– 2.0L I-4
– 1.6L I-4
– 2.3L I-4
– 2.7L V-6
– 3.5L V-6
Toyota currently sells no turbo petrol engine
- 1.0L 3-cyl
- 1.5L 4-cyl
- 2.0L 4-cyl
- SGE 1.0L 3-cyl
- Family 0- 1.4L 4-cyl
- Family 1- 1.6L
- Family 2- Z20LET 2.0L
-EcoTec LK9 2.0L
-EcoTec LNF 2.0L
-EcoTec LHU 2.0L
-EcoTec LTG 2.0L
Another very recent advancement is the introduction of 3 cylinder 1.0L turbo petrol engines. They are the current rage in the industry. With giants like GM, Ford and Honda having already launched this type of engine, Suzuki and VW are soon to follow. Such engines enable the manufacturer to plonk it in an array of vehicles as they are very tiny in size but produce the power comparable to that of a 1.5L naturally aspirated one with the help of some great engineering techniques. That is one hell of a technology that can please the green headed people as well as the auto enthusiast type.
Turbochargers are now well and fully back in the scene. Need more power and torque? Go the turbocharger way. This is how it will stay at least for the near future, and no one is complaining.