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Home >> Infiniti >> 2024 >> QX55 Essential >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (1 Of 2) >> System Description >> System >> VCR (Variable Compression Ratio) System >> System Description
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System Description

SYSTEM DIAGRAM 

GNSDB138988Courtesy of NISSAN NORTH AMERICA, INC.
Component parts Function
Crankshaft position sensor Crankshaft Position Sensor 
Engine Coolant Temperature Sensor 1 Engine Coolant Temperature Sensor 
Engine Oil Temperature Sensor Engine Oil Temperature Sensor 
Accelerator Pedal Position Sensor Accelerator Pedal Position Sensor 
Knock Sensor Knock Sensor 
Combination meter ECM receives the vehicle speed signal via CAN communication.
TCM ECM receives the G sensor signal via CAN communication.
ECM ECM 
VCR control module Variable Compression Ratio Control Module 
VCR actuator Variable Compression Ratio Actuator 

SYSTEM DESCRIPTION 

VCR system improves the fuel economy, engine output, and exhaust performance. by variably changing the compression ratio of the engine. VCR control module continuously controls the compression ratio of the engine by operating VCR actuator to change the angle of VCR control shaft. VCR control module controls VCR actuator according to a signal from ECM to change the compression ratio of the engine. VCR control module has a diagnostic function and transmits a DTC detection signal to ECM via CAN communication when detecting a system error.