Vanos Overview

VANOS OVERVIEW




The M5 engine uses a double vanos system for valve timing on both the intake and exhaust camshafts Unlike the M62 TU system, the M5 uses a high pressure (100 Bar) control system that ensures quick and reliable adjustments of the camshafts to meet the high performance requirements of the 5 liter engine. The 100 Bar single VANOS system was introduced in 1992 on the European M3 and expanded to double VANOS in 1995. The system used on the M5 S62 engine is primarily the same as the double VANOS of the European M3.

The VANOS operating principle remains the same in that engine power output, torque rating, lower fuel consumption, idle quality and low exhaust emissions are all improved through the use of this double VANOS system.

VANOS COMPONENTS

The VANOS system of the S62 engine consists of the following components:

VANOS HYDRAULIC UNIT




The hydraulic unit contains:
- High pressure radial pump (driven by the intake Camshaft).
- Two inlet solenoids.
- Two exhaust solenoids.
- Two adjustment pistons.

TWO CAMSHAFT GEARS WITH HELICAL GEAR INTERNAL SPLINES




TWO ADJUSTMENT SHAFTS




The adjustment shaft has external helical cut splines and external straight cut spur splines.

CAMSHAFTS




The splined sleeves with the straight cut splines are bolted to the camshafts.

PRESSURE REDUCING VALVE (5 to .5 Bar)




The reducing valve supplies the oil to the high pressure radial pump. It is mounted in the cylinder head behind the VANOS hydraulic unit. The supply pressure to the VANOS unit must be reduced to ensure that the pressure pump will develop the 100 Bar pressure required for VANOS operation. Each cylinder head contains the pressure reducing valve.

100 BAR PRESSURE REGULATOR




The 100 Bar pressure regulator is mounted in the center of the cylinder block "V" on the thermostat housing. It ensures that the oil pressure for VANOS operation is held to 100 bar. One pressure regulator is used for both cylinder banks.

100 BAR PRESSURE ACCUMULATOR
The pressure accumulator ensures that there is a sufficient volume of oil under pressure to adjust the camshafts under all engine operating conditions. It is mounted to the left side of the thermostat housing on the front of the cylinder block.