System Operation
Lubrication System
| Item | Description |
|---|---|
| 1 | Oil pump |
| 2 | Oil pump screen and pickup tube |
| 3 | Piston oil cool valve |
| 4 | Crankshaft |
| 5 | Engine main bearing cap support |
| 6 | Oil pan |
| 7 | Oil filter |
| 8 | Oil cooler (if equipped) |
| 9 | Oil filter adapter |
| 10 | Oil pressure switch |
| 11 | LH cylinder head |
| 12 | Exhaust camshaft |
| 13 | Intake camshaft |
| 14 | LH camshaft cap |
| 15 | LH valve train oil feed tube |
| 16 | LH secondary timing chain tensioner |
| 17 | LH camshaft mega cap |
| 18 | LH intake and exhaust camshaft Variable Camshaft Timing (VCT) oil control solenoid |
| 19 | LH exhaust camshaft VCT |
| 20 | LH intake camshaft VCT |
| 21 | RH camshaft cap |
| 22 | RH valve train oil feed tube |
| 23 | RH secondary timing chain tensioner |
| 24 | RH camshaft mega cap |
| 25 | RH intake and exhaust camshaft VCT oil control solenoid |
| 26 | RH exhaust camshaft VCT |
| 27 | RH intake camshaft VCT |
| 28 | RH cylinder head |
| 29 | Cylinder block |
| 30 | Primary timing chain tensioner |
Oil Pump
The engine lubrication system is of the force-feed type in which oil is supplied under full pressure to the crankshaft, connecting rod bearings, timing chain tensioners, piston oil cooling jets and VCT oil control solenoids. The flow of oil to the valve tappets and valve train is controlled by a restricting orifice located in the cylinder head, front camshaft cap.
The lubrication system is designed to provide optimum oil flow to critical components of the engine through its entire operating range.
The heart of the system is a positive displacement internal gear oil pump.
Generically, this design is known as a gerotor pump, which operates as follows:
- The oil pump is mounted on the front face of the cylinder block.
- The inner rotor is piloted on the crankshaft post and is driven through flats on the crankshaft.
- System pressure is limited by an integral, internally-vented relief valve which directs the bypassed oil back to the inlet side of the oil pump.
- Oil pump displacement has been selected to provide adequate volume to make sure of correct oil pressure both at hot idle and maximum speed.
- The relief valve calibration protects the system from excessive pressure during high-viscosity conditions.
- The relief valve is designed to provide adequate connecting rod bearing lubrication under high temperature and high-speed conditions.
Valve Train
The valve train uses direct acting mechanical buckets (DAMB). The camshaft lobes are positioned directly above mechanical buckets which are positioned on top of the valves.
Twin Independent Variable Cam Timing (Ti-VCT)
The twin independent VCT system allows variable control of the valves closing which optimizes combustion at full load providing improved power and low speed torque (broadening the torque curve) which enables variable valve overlap which provides better fuel economy and emissions and provides optimized cold start operation with improved exhaust emissions.