Ti Variable Valve Timingintelligent System General

► 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 improves torque in all the speed ranges as well as increasing fuel economy, and reducing exhaust emissions.

► Using the engine speed, intake air volume, throttle position and water temperature, the ECM can calculate optimal valve timing for each driving condition and controls the camshaft timing oil control valve. In addition, the ECM uses signals from the camshaft position sensor and the crankshaft position sensor to detect the actual valve timing, thus providing feedback control to achieve the target valve timing.

Effectiveness of the VVT-i System

Operation State

Objective

Effect

► During Idling

Latest Timing

IN Minimizing overlap to prevent blow back to the intake side

Latest Timing

IN Minimizing overlap to prevent blow back to the intake side

►Stabilized idling rpm ► Better fuel economy

to Advance Side

At Medium Load

to Advance Side

Increasing overlap to increase internal EGR to reduce pumping loss

►Better fuel economy ►Improved emission control

In Low to Medium

Speed Range with Heavy Load

Advancing the intake valve IN close timing for volumetric efficiency improvement to Advance Side

to Advance Side

Advancing the intake valve IN close timing for volumetric efficiency improvement

Improved torque in low to medium speed range

In High Speed Range with Heavy Load

Retarding the intake valve IN close timing for volumetric efficiency improvement to Retard Side

to Retard Side

Retarding the intake valve IN close timing for volumetric efficiency improvement

Improved output

At Low Temp.

Latest Timing

Minimizing overlap to prevent IN blow back to the intake side

Latest Timing

Minimizing overlap to prevent IN blow back to the intake side

►Stabilized fast idle rpm ►Better fuel economy

►Upon Starting ►Stopping the Engine

Latest Timing

Minimizing overlap to prevent IN blow back to the intake side

Latest Timing

Minimizing overlap to prevent IN blow back to the intake side

Improved startability

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