TECH: BORG WARNER E-TURBO

BLOWING F1 TECH INTO PRODUCTION CARS

Electric turbos have come a long way since that time you blew your Alloytec up with a Chinese hairdryer from eBay

Unplugged, BorgWarner’s new eTurbo works exactly as a conventional turbocharger does. Connect the power, however, and an electric motor located on the central driveshaft brings significant advances to an old idea.

At low engine revs, the energised motor can spool the turbo up to speed almost instantly, eliminating lag. Once the engine is running at high revs, the motor takes a back seat and allows exhaust gasses to take over.

In a conventional turbo, a wastegate bypasses excess exhaust to prevent overboosting. Instead, the eTurbo switches polarity to turn the motor into a generator, and the load applied to the driveshaft precisely limits its maximum speed. Regenerated power is stored in an electrical sub-system to power the anti-lag function or any other high-power electrical systems the vehicle may have. In hybrids, the extra power extends battery range.

Complex boost control systems such as variable vanes are redundant with this innovation, while the electric turbo also has the potential to reduce emissions. When an engine starts, its cold turbo absorbs a large amount of heat from the exhaust, delaying the catalytic converter’s ‘light-off’ point. The eTurbo’s bypass valve directs gasses directly to the cat, slashing coldstart emissions. While diverted, the electric motor looks after boost duties.

The same principle is proving itself in Formula 1, boosting the efficiency of the 1.6-litre V6 race engines without compromising power. The first production vehicles with electrified turbos are expected by 2022.