Exhaust Camshaft
| Callout | Component Name |
|---|---|
| 1 | Vane Wheel |
| 2 | CMP Actuator Housing, part of CMP actuator assembly |
| 3 | Exhaust Camshaft Gear, part of CMP actuator assembly |
| 4 | Ehaust Camshaft |
| 5 | Advance Side Oil Passage, applying pressure |
| 6 | CMP Actuator Solenoid Valve |
| 7 | Retard Side Oil Passage, relieving pressure |
Oil flowing to the CMP actuator housing (2) from the CMP solenoid advance passage (5) applies pressure to the advance side of the vane wheel (1) in the CMP actuator assembly. At the same time the CMP solenoid retard passage (7) is open, allowing oil pressure to decrease on the retard side of the vane wheel. These two simultaneous actions cause the vane wheel (1) to rotate clockwise, advancing the exhaust camshaft up to a maximum of 55 degrees.
| Callout | Component Name |
|---|---|
| 1 | Vane Wheel |
| 2 | CMP Actuator Housing, part of CMP actuator assembly |
| 3 | Exhaust Camshaft Gear, part of CMP actuator assembly |
| 4 | Exhaust Camshaft |
| 5 | Advance Side Oil Passage, relieving pressure |
| 6 | CMP Actuator Solenoid Valve |
| 7 | Retard Side Oil Passage, applying pressure |
When the oil flowing to the CMP actuator housing (2) is from the CMP solenoid retard passage (7), oil pressure is applied to the retard side of the vane wheel (1). Because the solenoid advance passage (5) is open, allowing oil pressure to decrease on the advance side of the vane wheel (1), the exhaust camshaft position retards.
The PCM can also command the CMP actuator solenoid valves to stop oil flow from both passages in order to hold the current camshaft position. The PCM is continuously comparing CMP sensor input with CKP sensor input in order to monitor camshaft position and detect any system malfunctions. The following table provides camshaft phase commands for common driving conditions:
| Driving Condition | Change in Camshaft Position | Objective | Result |
|---|---|---|---|
| Engine Warm-up | No Change, Zero Advance | Minimize Valve Overlap | Stabilize Fast Idle Speeds and Improved Fuel Economy |
| Light Engine Load | Retard Valve Timing | Decrease Valve Overlap | Stable Engine Output |
| Medium Engine Load | Advance Intake and Exhaust Valve Timing | Increase Valve Overlap | Better Fuel Economy and Increased Internal EGR Effect for Lower Emissions |
| Low to Medium RPM with Heavy Load | Advance Intake and Exhaust Valve Timing | Advance Intake Valve Closing | Improved Low to Mid-range Torque |
| High RPM with Heavy Load | Retard Valve Timing | Retard Intake Valve Closing | Improve Engine Output |
| Idle | No Change, Zero Advance | Minimize Valve Overlap | Stabilize Idle Speed |