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Tuesday, January 31, 2023

on video Understanding variable camshaft technology in cars


 1. Structure of VVT-i variable valve system:

The actuator of the VVT-i system includes the VVT-i controller used to rotate the intake camshaft, the oil pressure used as the rotation force for the VVT-i controller and the camshaft coordination oil control valve to control the intake camshaft. oil path.

System components include: 32-bit ECU Central Processing Unit; pump and oil lines; air conditioning control unit (VVT) with solenoid valves; sensors: VVT, throttle position, intake air flow, crankshaft position, water temperature. In addition, VVT-i is often designed in sync with ETCS-i electronic throttle mechanism, 12-hole fuel injector (removing gas support) and electronic distributor and iridium spark plugs. .

The VVT-i controller consists of a housing driven by the cam chain and the vanes are fixed on the intake camshaft, the oil pressure sent from the intake camshaft early or delay side rotates the actuator vanes. VVT-i control to continuously change the timing of the intake camshaft. When the engine stops, the intake camshaft moves to the latest state to maintain starting ability. When the oil pressure does not reach the VVT-i controller immediately after the engine is started, the locking pin will brake the actuators of the VVT-i controller to avoid knocking.


2. Working principle of VVT-i system:

During operation, the throttle position and intake air flow sensors provide key data about the ECU to calculate the desired air distribution parameters actively. The engine coolant temperature sensor provides calibration data, and the VVT cam and crankshaft position sensors provide information about the actual air condition.


On the basis of active, calibrated and actual factors, the ECU will synthesize the optimal distribution command for the combustion chamber. This command is calculated in milliseconds and decides to close (open) the solenoid valves of the hydraulic system. The oil pressure will change the position of the distribution controller, opening the intake valves as needed at the right time.


Thus, instead of the old cam system with a constant valve opening, VVT-i has infinitely adjusted the operation of the intake valves. The opening and opening times vary according to the combination of parameters of intake air flow, throttle position, engine speed and temperature.

3. Operation mode of VVT-i intelligent variable valve system?

VVT-i intelligent variable valve system has 3 operating modes depending on the operating status of the engine.

a. Make early mixing time:

When the camshaft coordination oil control valve is set to the position shown in the figure by the engine ECU, the oil pressure is applied to the vane chamber on the front of the timing side to rotate the intake camshaft to the direction of timing advance. air lung.


 1. Structure of VVT-i variable valve system:

The actuator of the VVT-i system includes the VVT-i controller used to rotate the intake camshaft, the oil pressure used as the rotation force for the VVT-i controller and the camshaft coordination oil control valve to control the intake camshaft. oil path.

System components include: 32-bit ECU Central Processing Unit; pump and oil lines; air conditioning control unit (VVT) with solenoid valves; sensors: VVT, throttle position, intake air flow, crankshaft position, water temperature. In addition, VVT-i is often designed in sync with ETCS-i electronic throttle mechanism, 12-hole fuel injector (removing gas support) and electronic distributor and iridium spark plugs. .

The VVT-i controller consists of a housing driven by the cam chain and the vanes are fixed on the intake camshaft, the oil pressure sent from the intake camshaft early or delay side rotates the actuator vanes. VVT-i control to continuously change the timing of the intake camshaft. When the engine stops, the intake camshaft moves to the latest state to maintain starting ability. When the oil pressure does not reach the VVT-i controller immediately after the engine is started, the locking pin will brake the actuators of the VVT-i controller to avoid knocking.


2. Working principle of VVT-i system:

During operation, the throttle position and intake air flow sensors provide key data about the ECU to calculate the desired air distribution parameters actively. The engine coolant temperature sensor provides calibration data, and the VVT cam and crankshaft position sensors provide information about the actual air condition.


On the basis of active, calibrated and actual factors, the ECU will synthesize the optimal distribution command for the combustion chamber. This command is calculated in milliseconds and decides to close (open) the solenoid valves of the hydraulic system. The oil pressure will change the position of the distribution controller, opening the intake valves as needed at the right time.


Thus, instead of the old cam system with a constant valve opening, VVT-i has infinitely adjusted the operation of the intake valves. The opening and opening times vary according to the combination of parameters of intake air flow, throttle position, engine speed and temperature.

3. Operation mode of VVT-i intelligent variable valve system?

VVT-i intelligent variable valve system has 3 operating modes depending on the operating status of the engine.

a. Make early mixing time:

When the camshaft coordination oil control valve is set to the position shown in the figure by the engine ECU, the oil pressure is applied to the vane chamber on the front of the timing side to rotate the intake camshaft to the direction of timing advance. air lung.

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