Abstract: A turbocharger system for an internal combustion engine comprises two turbochargers each having a turbine (5, 6) drivably connected to a compressor (7, 8). Temperature sensors (19, 20) are disposed to sense the temperature at the compressor outputs. The temperature are monitored to give an indication of an imbalance condition for which corrective action may be taken. The arrangement provides for reliable and inexpensive monitoring.

Abstract: Pressure charging apparatus, which may be a turbocharger or a supercharger, for an internal combustion engine comprises a pressure supply, a wastegate, a wastegate actuator for closing and opening the wastegate in order to alter the pressure in the engine inlet, a boost control for controlling the wastegate actuator, a boost control solenoid valve, a switchover valve, electronic control units and a full throttle sensor. In operation, unit receives signals, inter alia, from the sensor to control valves to positively shut the wastegate until an overboost threshold is reached thereby minimizing boost lag during this period.