Car Engine Camshaft Phase Regulater(VVT) Manufacturers

Working Principle and Key Technology Analysis of Camshaft Phase Regulator (VVT)

Camshaft Phase Regulator (Camshaft Phase Regulator), commonly known as Variable Valve Timing (VVT), is one of the key technologies of modern automobile engines. It optimizes the valve opening and closing timing by dynamically adjusting the phase angle of the camshaft relative to the crankshaft, thereby improving the fuel economy, power output and emission performance of the engine.

Core Working Principle

The basic principle of the VVT ​​system is to adjust the opening and closing time of the intake valve and/or exhaust valve by changing the relative position between the camshaft and the crankshaft. Its core components include:
Phaser: Usually a hydraulic or electric structure, responsible for adjusting the camshaft angle.
Control Valve (OCV, Oil Control Valve): Regulates the flow direction of the engine oil and drives the phase regulator to operate.
ECU (Engine Control Unit): Calculates the optimal valve timing based on parameters such as speed and load, and sends instructions.

Hydraulic VVT (oil pressure drive)
Most traditional VVT systems are hydraulically driven, and the working principle is as follows:
Oil pressure drive: The engine oil enters the rotor cavity inside the phase adjuster through the OCV, pushing the rotor to rotate relative to the housing.

Phase adjustment:
Advance phase: The oil pushes the rotor to move in the advance direction, causing the valve to open early.
Delay phase: The oil flows to the other side, causing the valve to close late.
Locking mechanism: Some systems lock the phase at idle or low speed to ensure stable operation.

Electric VVT (motor drive)
The new generation of VVT systems uses direct motor drive (such as eCVVT), and the advantages include:
Faster response: It is not affected by oil pressure and temperature, and is suitable for hybrid/pure electric models.
More precise control: The motor can be infinitely adjusted to achieve more complex valve timing strategies.

Key technology analysis

Oil circuit and sealing technology
Hydraulic VVT relies on high-precision oil circuit design to ensure fast oil response.
Seals (such as rubber O-rings) need to be resistant to high temperatures and aging to avoid oil leakage and failure of regulation.

Control strategy
Open-loop control: adjust the phase based on the preset MAP (map).
Closed-loop control: adjust in real time through camshaft position sensor (CMP) feedback to improve accuracy.

Materials and lightweight
Aluminum alloy housing + high-strength rotor to reduce inertia and improve dynamic response.
Electric VVT uses high-torque density motor to reduce volume and weight.