The power of turbocharge technology
SAAB has developed a new method of turbocharging using a lower boost pressure than in a conventional turbo engine.
This new approach has resulted in the Ecopower engine, used to power the Saab 9000 CD. It also has a flat torque curve and delivers a high and uniform pulling force over a wide range of engine speeds, resulting in a 30 per cent improvement in overtaking acceleration, according to Saab.
The engine also offers environmental benefits, since the exhaust emissions have been reduced.
The Ecopower engine concept represents a new application of turbocharging technology, says Saab, and is aimed at improving the performance of the injection engine.
With this approach, turbocharging is not used for achieving the highest output, but for assisting the injection engine and enabling it to deliver higher torque over a wide range of engine speeds.
Saab says engine torque rather than maximum power makes a car safe and comfortable. The maximum horsepower determines only the speed the car can reach in each gear, but the nature of the torque curve determines how the driver will perceive the interaction between the car and the engine in normal traffic, particularly when overtaking.
A frequently disregarded effect of turbocharging is the silencing capacity of the turbocharger, reducing the sound level in the exhaust system, intake pipe and combustion chamber.
The Saab 9000 CD with the Ecopower engine is quieter than the same car without the turbocharger.
Although it delivers an additional 20 horsepower, the Ecopower engine has basically the same fuel consumption under comparable motoring conditions as the normal injection engine. This is because the turbocharger consumes no power.
The exhaust emissions of a turbocharged engine are due to the engine's more complete combustion.
Compared with an injection powerplant with the same performance, Saab claims the Ecopower engine emits 30 per cent lower hydro carbons, 10 per cent reduced carbon oxide and 40 per cent lower nitrogen oxide.