Turbochargers are typically driven by only the exhaust gas exiting an engine, which takes some time to accelerate the turbine. This leads to what’s known as turbo lag, which is that moment right after you step on the accelerator pedal when not much happens, before the full effect of the boost kicks in.
Automakers have developed various measures to minimize the effect, including the combination of an engine-driven supercharger, which delivers boost at low engine speeds until the turbocharger takes over at high revs. Volvo currentlyoffers an engine with this type of arrangement in several of its vehicles.
But its new PowerPulse technology approaches this issue in an even more novel way. It features an electric air compressor that fills a two-liter canister with filtered pressurized air, releasing it into the exhaust manifold in bursts or “pulses” whenever you step on the accelerator. This quickly brings the turbo up to speed, filling the gap and virtually eliminating lag, Volvo says.