Turbocharger Wastegate Regulating Valve Solenoid

1-40 Description and Operation

Engine Control Components

Turbocharger Wastegate Regulating Valve Solenoid

The turbocharger wastegate regulating valve solenoid allows the PCM to control the turbocharger wastegate position. The turbocharger wastegate regulating valve solenoid controls the pressure or vacuum supplied to the pneumatically actuated wastegate diaphragm in order to control the boost pressure limit. When the compressor outlet pressure increases, a pneumatically powered actuator opens the turbocharger wastegate and limits the compressor outlet pressure. The turbocharger wastegate regulating valve solenoid supplies pressure or vacuum to the pneumatically actuated wastegate canister diaphragm, which regulates the boost pressure to the desired value.

For the pressure actuated turbocharger wastegate, the turbocharger wastegate regulating valve solenoid controls the pressure applied to the turbocharger wastegate actuator. The amount of pressure vented from the pneumatic turbocharger wastegate actuator allows the PCM to control boost pressure. To generate maximum boost pressure, the PCM controls the turbocharger wastegate regulating valve solenoid to completely vent the pressure being applied to the turbocharger wastegate actuator. If a concern is present, the spring pressure in the pneumatic turbocharger wastegate actuator defaults the turbocharger wastegate to a fully closed position.

For the vacuum actuated turbocharger wastegate, the turbocharger wastegate regulating valve solenoid controls vacuum applied to the turbocharger wastegate actuator. The amount of vacuum applied to the turbocharger wastegate actuator allows the PCM to control the boost pressure. To generate maximum boost pressure, the PCM controls the turbocharger wastegate regulating valve solenoid to apply full vacuum to the turbocharger wastegate actuator. If a concern is present, the spring pressure in the pneumatic turbocharger wastegate actuator defaults the turbocharger wastegate to a fully open position.

Typical Turbocharger Wastegate Regulating Valve Solenoid (Pressure Actuated Wastegate)

Typical Turbocharger Wastegate Regulating Valve Solenoid (Vacuum Actuated Wastegate)

Universal Heated Oxygen Sensor (HO2S)

The universal HO2S, sometimes referred to as a wideband oxygen sensor, uses the typical HO2S combined with a current controller in the PCM to infer an air to fuel ratio relative to the stoichiometric air to fuel ratio. This is accomplished by balancing the amount of oxygen ions pumped in or out of a measurement chamber within the sensor. The typical HO2S within the universal HO2S detects the oxygen content of the exhaust gas in the measurement chamber. The oxygen content inside the measurement chamber is maintained at the stoichiometric air to fuel ratio by pumping oxygen ions in and out of the measurement chamber. As the exhaust gasses get richer or leaner, the amount of oxygen that must be pumped in or out to maintain a stoichiometric air to fuel ratio in the measurement chamber varies in proportion to the air to fuel ratio. The amount of current required to pump the oxygen ions in or out of the measurement chamber is used to measure the air to fuel ratio. The measured air to fuel ratio is actually the output from the current controller in the PCM and not a signal that comes directly from the sensor.

2016 Powertrain Control/Emissions Diagnosis, Gasoline Engines, 3/2015