The Volvo PowerPulse is a simple solution for eliminating the turbo-lag phenomenon via pulses of compressed air to the turbocharger. The Swedish company, Volvo, had stated that their engine would not have a capacity of more than 2,000 cm³, and thus had problems building a small unit that would perform well in a high-end car.
The large XC90, S90, and V90 models require high torque values and instant gas response to match their larger 6-cylinder, liter-capacity competitors. The engineers used a sequential dual turbocharger boost system and a smart and simple PowerPulse system on the 2.0-liter diesel engine.
The principle of operation of the PowerPulse system
A two liter compressed air tank is attached to the power unit. The electric compressor pulls it from the intake system and forces it into the tank. It is used when the engine has heavy loads in the low RPM range, where the turbocharger cannot immediately produce high thrust pressure.
The driver presses the gas and the system activates a valve in the tank which forces air into the exhaust manifold through the turbine wheels. This helps it accelerate faster and, according to Volvo engineers, deliver high torque faster than the competing 3.0-liter 6-cylinder engine.