Dual VVT-i

Dual VVT-i

◆ The VVT-i system only controls and adjusts the timing of the intake valve, while the dual VVT-i system controls and adjusts both the intake and exhaust valves. Relatively speaking, the dual VVT-i system can make the engine run more efficiently.

◆ The dual VVT-i system of Toyota Corolla can control the intake system and exhaust system of the engine separately. During rapid acceleration, the VVT-i that controls the intake will advance the intake, while the VVT-i that controls the exhaust will delay the exhaust. This effect is like a smaller turbocharger, which can effectively increase the engine power. At the same time, due to the increase of the intake air volume, the combustion of gasoline is more complete and the purpose of low emission is achieved.

◆ The engine ECU calculates an optimal valve timing according to the engine speed, intake air volume, throttle position and water temperature, and sends control instructions to the camshaft timing oil control valve. The camshaft timing oil control valve selects different oil circuits to the VVT-i controller according to the commands sent out, so that it is in advance, lag or maintain three different working states. In addition, the engine ECU detects the actual valve timing based on the signals from the camshaft and crankshaft position sensors to perform feedback control as much as possible so as to obtain the predetermined Variable Valve Timing.