System Description
The wastegate is installed inside the exhaust side housing of turbocharger and connected via electric wastegate control actuator and link rod. When the wastegate opens, part of exhaust gas directly flows into exhaust pipe through bypass without passing the turbine. This limits the rise in boost pressure.
Furthermore, the introduction of electrically-controlled wastegate control valve enables the wastegate valve to be opened even in non-supercharging area, improving fuel consumption by the reduction of pumping loss.
*: Turbocharger speed sensor is not used for turbo low pressure model
ECM controls boost pressure to make it suitable for driving conditions by controlling the electric wastegate control actuator.
ECM judges a target boost pressure based on engine speed, accelerator pedal position, and throttle valve position and calculates suction pressure near the entrance of compressor according to the amount of intake air and intake air pressure. Based on the above mentioned information, ECM judges wastegate valve opening angle to satisfy the target boost pressure.
Furthermore, the revolution speed of compressor blade is directly monitored with a turbocharger speed sensor. This enables more accurate control of boost pressure and reduces damage to turbocharger caused by excess rise in revolution.