Description And Operation
When the throttle plate is closed suddenly, excessive boost pressure can build up between the turbocharger and the throttle body. This can occur because the compressed air created by the turbocharger is trapped. This results in compressor surge which can cause compressor lag or damage to the turbocharger. The Turbocharger Surge Valve (TSV) (1) is used to vent the boost pressure trapped between the turbocharger and throttle body when the throttle plate is closed suddenly. The TSV is spring loaded open, but during normal engine operation the TSV is energized by the Powertrain Control Module (PCM) to hold it in the closed position and allow boost.
When a pressure surge is detected, the TSV is de-energized and the spring-loaded valve is opened. When open, the valve routes the pressure trapped between the turbocharger and the throttle body back to the inlet of the turbocharger, relieving the pressure and preventing compressor surge. The TSV is controlled by the PCM using a Low Side Driver (LSD) inside the PCM.