Vvt-I (Variable Valve Timing-Intelligent) System - Toyota 1NZ-FE User Manual

7. VVT-i (Variable Valve Timing-intelligent) System

General
D The VVT-i system is designed to control the intake camshaft within a range of 40_ (of Crankshaft Angle)
to provide valve timing that is optimally suited to the engine condition. This realizes proper torque in
all the speed ranges as well as realizing excellent fuel economy, and reducing exhaust emissions.
D Using the engine speed signal, vehicle speed signal, and the signals from mass air flow meter, throttle
position sensor and water temperature sensor, the engine ECU can calculate optimal valve timing for
each driving condition and controls the camshaft timing oil control valve. In addition, the engine ECU
uses signals from the camshaft position sensor and crankshaft position sensor to detect the actual valve
timing, thus providing feedback control to achieve the target valve timing.
Crankshaft Position Sensor
Mass Air Flow Meter
Throttle Position Sensor
Engine Coolant Temp. Sensor
Camshaft Position Sensor
Vehicle Speed Sensor
ENGINE - 1NZ-FE ENGINE
Camshaft Timing Oil Control Valve
Camshaft Position
Sensor
Engine Coolant
Temperature
Sensor
Crankshaft Position Sensor
Target Valve Timing
Correction
Actual Valve Timing
Throttle Position
Sensor
ECM
Mass Air
Flow Meter
247EG23
Camshaft
Timing
Oil
control
Duty-cycle
Valve
Control
Feedback
221EG16
EG-41