Variable Camshaft Timing Components
| ITEM | DESCRIPTION |
|---|---|
| 1 | Inlet Variable Camshaft Timing (VCT) actuator assembly |
| 2 | Exhaust VCT actuator assembly |
| 3 | Exhaust VCT solenoid |
| 4 | Camshaft Position (CMP) sensors |
| 5 | Inlet VCT solenoid |
The timing of the inlet and exhaust camshafts can be adjusted independently by an electro-hydraulic controlled Variable Camshaft Timing (VCT) system. The Powertrain Control Module (PCM) controls the system using information from the Camshaft Position (CMP) sensors and the Crankshaft Position (CKP) sensor.
The VCT system varies the timing of the intake and exhaust camshafts to deliver optimum engine power, efficiency and emissions. The timing of the intake camshafts has a range of 62 degrees of crankshaft angle. The timing of the exhaust camshafts has a range of 50 degrees of crankshaft angle.
In the base timing position:
- The intake camshafts are fully retarded.
- The exhaust camshafts are fully advanced.
Variable Camshaft Timing Operating Ranges
| CAMSHAFT | VALVE OPENS | VALVE CLOSES |
|---|---|---|
| Intake | 33° Before Top Dead Center (BTDC) to 29° After Top Dead Center (ATDC) | 197 to 259° ATDC |
| Exhaust | 236 to 186° BTDC | 6 to 56° ATDC |
The system consists of a VCT actuator and a VCT solenoid for each camshaft. The PCM controls the system using Pulse Width Modulation (PWM) signals to the VCT solenoids.
The torsional energy generated by the valve springs and the inertia of the valve train components are used to operate the system.