System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN NORTH AMERICA, INC.

Component parts	Function
Crankshaft position sensor	Crankshaft Position Sensor .
Intake camshaft position sensor	Intake Camshaft Position Sensor .
Mass air flow sensor	Mass Air Flow Sensor .
Intake air temperature sensor 1	Mass Air Flow Sensor .
Intake air temperature sensor 2	Turbocharger Boost Sensor (With Intake Air Temperature Sensor 2) .
Engine coolant temperature sensor 1	Engine Coolant Temperature Sensor .
Throttle position sensor	Electric Throttle Control Actuator .
Accelerator pedal position sensor	Accelerator Pedal Position Sensor .
Turbocharger Boost Sensor	Turbocharger Boost Sensor (With Intake Air Temperature Sensor 2) .
ECM	ECM .
Electric wastegate control actuator	Turbocharger .
Turbocharger bypass control valve

SYSTEM DESCRIPTION 

ECM controls the electric wastegate control actuator according to driving conditions. The rod connected to the electric wastegate control actuator controls turbocharger boost by changing the angle of the wastegate valve in the exhaust side turbine. ECM determines a target boost pressure based on engine speed, accelerator pedal position, and throttle valve position. ECM then calculates intake air pressure around the turbine entrance according to the amount of intake air and intake air pressure. Based on this information, ECM determines the wastegate valve angle to satisfy the target boost pressure. The electronically-controlled wastegate control actuator enables the adjustment of wastegate valve angle, allowing the improvement of the response to driving conditions and the achievement of high-precision boost pressure control. When the engine is cold, the wastegate valve is opened and heat loss caused by turbocharger is minimized to accelerate the warm-up (activation) of catalyst. This allows the wastegate valve to be opened in non-supercharging regions and improves the fuel economy by reducing piston pumping loss. In addition, the adoption of the electronically-controlled turbocharger bypass control valve quickly starts opening the bypass valve when releasing the accelerator pedal, and accordingly this reduces surge sound generated by the back flow of supercharged air to the compressor fin.