Twincharged

Twincharged refers to an internal combustion engine that uses both a turbocharger and a supercharger to supply boosted air to the engine. The goal is to combine the advantages of each device: the supercharger provides immediate boost at low engine speeds, while the turbocharger delivers higher boost and efficiency at higher RPMs once exhaust energy is available. Systems are typically designed to avoid conflicts between the two compressors, using control strategies, bypass valves, intercooling, and sometimes clutch mechanisms.

There are a couple of common configurations. In a sequential setup, the supercharger delivers boost at low RPM, and as engine speed rises and the turbo spools, the system shifts emphasis toward the turbo, which may reduce or bypass the supercharger. In some parallel designs, the two compressors feed the intake together but are managed so that one dominates under certain conditions. Some implementations place the devices in series on the intake path, with the supercharger driving the turbo path at low speed to shorten lag.

Benefits of twincharging include improved low-end torque and throttle response, wider usable torque across the rev range, and better performance in small-displacement engines. Challenges involve increased mechanical complexity, higher cost, packaging constraints, and the need for advanced control strategies to optimize efficiency and reliability.

Notable examples include Volkswagen Group’s 1.4-liter TSI Twincharger family, which paired a belt-driven supercharger with a small turbocharger. The concept has influenced other manufacturers and remains a reference point in discussions of broad-reaching forced-induction strategies.