Technology
TSI (Turbo Stratified Injection)
Small engine. Big results.
Automotive breakthroughs that successfully challenge ideas and shake up the rulebook only come along once in a while. As the first engine in history to combine turbocharging, supercharging and direct fuel injection, Volkswagen’s twincharged TSI petrol engine is one such breakthrough.
In fact, it’s so advanced that it has held the title ‘Engine of the Year’ in the category ‘1.0 to 1.4 litre engines’ for four years running. In 2009 Volkswagen’s twincharged 1.4 TSI engine was announced ‘International Engine of the Year’ and ‘Green Engine of the Year’.
What is Stratified Injection and where did it start?
Stratified Injection has its roots in Volkswagen’s TDI (Turbo Direct Injection) technology. Direct injection technology has become synonymous with impressive torque output and economical fuel efficiency. Injected fuel supply is carried out in different ways depending on the engine type and, following its great success in its diesel engine range, Volkswagen expanded their spectrum of direct injection systems to include petrol engines and called it Fuel Stratified Injection (FSI).
What is Turbo Stratified Injection?
Turbo Stratified Injection (TSI) marries direct injection with both a supercharger and a turbocharger (in the case of the smaller engines) or just a turbocharger (in the case of the larger engines) to further increase the performance of these engines. This means that you enjoy economical fuel consumption without compromising on engine performance. Volkswagen has a range of 1.4 TSI engines (which use one or both types of charging) and a range of 2.0 TSI engines that are turbocharged.
What makes the 1.4 TSI engine an award-winning engine?
While most engines are either turbocharged or supercharged, Volkswagen’s 1.4 TSI engine makes use of both – delivering a more thrilling surge of power right from the word go and using much less fuel than a comparable engine of a larger capacity.
A supercharger delivers power from very low engine speeds however, it tends to consume some of the engine’s energy at high revolutions. A turbocharger, on the other hand, enhances power delivery at high engine revolutions, but is not effective lower down. So why not combine the two?
That’s the brilliant concept behind TSI. The engine breathes compressed air from the supercharger until around 3,500rpm, at which point the turbocharger picks up the ball, driven by a powerful flow of exhaust gas. When the turbocharger starts working, the supercharger is disconnected from the engine by a small clutch, just to keep it from consuming engine power. A computer-controlled system switches seamlessly between the supercharger and turbocharger – meaning no delay between pressing the accelerator pedal and the continuous surge of power being delivered.
You get all the power of a 2.5 litre engine in the body of a 1.4. The 1.4 TSI engine can generate up to 125kW of power and still boast the most economical fuel consumption in its class at an astonishing 7.2 litres per 100 km. Not bad for a ‘lightweight’.
To read more about what makes the 1.4 TSI engine the 2009 International Engine of the Year, visit the Engine of the Year website.
