Scheme 370
Introduction
The new 6-cylinder N52 spark-ignition engine represents the start of a new generation of engine at BMW. Consistent lightweight construction methods and the development of other innovations have created an outstanding engine.
The N52 engine will be introduced with the MSV70 engine management in the following model series
- E60, E61, E63, E64
- E65, E66
- E85, E86
- E87
- E90, E91
MSV80 engine management is introduced with the introduction of the slightly modified N52 engine.
On the modified engine, there is, for example, no coolant temperature sensor on the radiator outlet. Depending on the model series and engine version concerned, the active air flap control system is used.
The 4th generation electronic immobilizer (EWS) is also introduced with the MSV80. The 4th generation EWS is an advanced development of the previous electronic immobilizer. This advanced development uses a new and modern encoding method.
The modified N52 engine with engine management MSV80 supersedes the previous engine with engine management MSV70 and is installed in the following model series
- E60, E61, E63, E64
- E70
- E83
- E81, E82, E87
- E90, E91, E92, E93
Brief description of components
- Crankcase made of magnesium-aluminium composite The crankcase consists of an aluminium-silicon insert, inseparably and seamlessly cast in with a magnesium alloy.
- innovative valve gear Valvetronic The Valvetronic consists of fully variable control of the valve lift combined with the variable camshaft control unit
- Volume-flow-regulated oil pump The new volume-flow-regulated oil pump delivers exactly the oil volume that is actually required.
- Electrical coolant pump The coolant pump driven by an electric motor is regulated irrespective of the engine speed.
- Three-phase differential air intake control The three-phase differential air intake control (DISA) ensures even cylinder fill levels
- Oil condition sensor For the N52 engine, the dipstick and its guide pipe are eliminated. The N52 engine has an oil condition sensor.
- DME: Digital engine electronics The digital engine electronics control and regulate the engine functions.
- Cylinder head cover made of magnesium
- Switchover to single-belt drive
- Highly temperature-resistant exhaust manifold
System functions
The following system functions are described
- Volume-flow-regulated oil supply
- Oil level check, engine oil quality check and engine oil temperature check
- Valvetronic
- Heat management
- Active air flap control
Volume-flow-regulated oil supply
The N52 has a volume-flow-regulated oil pump. This pump only delivers as much oil as each operating range of the engine requires. A conventional oil pump would have to be approximately three times the size of that in the N52 engine. This oil pump would also require more driving power accordingly.
No superfluous oil is supplied for ranges with a smaller load. The fuel consumption of the engine is reduced and wear to the oil is slowed down. A pendulum slide cell pump is used. The pump shaft is located off-center in the housing during pump activation. The impeller shifts radially during rotation. This means that the chambers on the impeller form different volumes. The oil is taken into the enlarging volume. The oil is pumped into the oil ducts at the reducing volume.
Oil level check, engine oil quality check and engine oil temperature check
The oil level is measured by the oil condition sensor and shown in the Central Information Display (CID). This protects the engine from excessively low oil level and the associated engine damage. Excessive oil filling of the engine, which can lead to leaks, is displayed as a check control message.
The oil condition sensor also registers the engine oil quality. This means that the system is able to compute exactly when it is necessary to change the engine oil. Condition Based Service (CBS) allows the engine oil to be changed in line with needs.
The engine oil temperature is also detected or calculated by the oil condition sensor. The signal from the oil condition sensor is evaluated in the DME. The evaluated signal is routed via the PT-CAN and K-CAN bus to the instrument cluster and to the CID.
Valvetronic
The Valvetronic consists of fully variable control of the valve lift combined with the variable camshaft control unit (VANOS).
The valve lift is only regulated on the inlet side, but the camshaft is also adjusted on the exhaust side. Valvetronic is controlled by
- a variable valve lift of the inlet valve
- a variable opening duration of the inlet valve
- a variable camshaft control of the inlet and exhaust camshaft (double VANOS)
The system is optimized by adapting the valve gear, changing the actuator motor and varying the camshaft timing control. Major innovations are
- On the intermediate lever, the plain bearing to the eccentric shaft has been replaced by a roller bearing. This reduces the friction in the valve gear.
- The guide of the intermediate lever is more precise. Only one spring is required to guide and retain the intermediate lever.
- The moved mass of the valve gear has been reduced by 13%.
- The range of motion of the inlet valves has been improved. The maximum lift has risen to 9.9 mm, but above all the minimum lift has been further reduced to 0.18 mm.
Heat management
The possibilities of conventional cooling systems are used for the cooling system with electrical coolant pump.
The following components are influenced by the heat management
- Electrical coolant pump
- Mapped thermostat
- Digital engine electronics (DME)
The cooling output of the system is adapted by means of a freely variable volumetric flow of the coolant.
The heat management determines the current cooling requirement and regulates the cooling system accordingly. If necessary, the coolant pump can even be switched off altogether, for example to heat up the coolant quickly during the warm-up phase.
If the engine is not running but very hot, the coolant pump will also work while the vehicle is out of use. Cooling output can thus be called up regardless of engine speed.
The heat management now permits various characteristic maps to be used as a basis for controlling the coolant pump, over and above the map thermostat. In this way, the engine control unit can adapt the engine temperature to the driving characteristics.
The engine control unit regulates the following temperature ranges
- 112°C = Economy
- 105°C = Normal
- 95°C = High
- 80°C = High and regulation by the map thermostat
If the vehicle handling causes the engine control unit to detect the economical operating range Economy, the DME regulates to a higher temperature (112 C).
In this temperature range, the engine is operated with a relatively fuel requirement. The friction inside the engine is reduced at higher temperature. The temperature increase thus favors lower fuel consumption in the low load range.
In the High and regulation by the map thermostat mode, the driver wants to use optimized power output development of the engine. To achieve this, the temperature in the cylinder head is lowered to 80°C. This lowering leads to a better cylinder filling, which leads in turn to an increase in engine torque. The engine control unit can now regulate a certain operating range, adapted to the relevant driving situation. This makes it possible to use the cooling system to influence consumption and performance.
Active air flap control
Active air flap control regulates the air supply for the engine and assemblies cooling system by only opening the air flaps as they are needed.
Scheme 371
Vacuum is principally used for the brake booster.
The vacuum in the inlet pipe depends on the varying engine load.
Diesel engines do not normally have any vacuum in the inlet pipe. Vacuum on diesel engines is provided by a pump that generates the required vacuum.
On spark-ignition engines with Valvetronic, the throttle valve is almost always open when driving. This means that there is a lower low air pressure in the intake manifold.
Spark-ignition engines with low vacuum in the inlet pipe also have a pump that generates additional vacuum.
The following components are involved in the vacuum supply system
- Mechanical vacuum pump A mechanic vacuum pump is fitted to diesel engines and spark-ignition engines with Valvetronic. The vacuum pump is mechanically driven by the engine, e.g. via the exhaust camshaft.
- Suction-jet pump As a rule, the suction-jet pump boosts the vacuum in the inlet pipe.
- Electric vacuum pump On some engines, an electric vacuum pump is fitted for additional vacuum supply. In certain temporary operating situations, the vacuum in the inlet pipe may be too low. In such cases, the inlet pipe vacuum cannot be adequately boosted by the suction-jet pump. In these situations, the electric vacuum pump ensures that sufficient vacuum is available. Reason: After a cold start, an operating situation occurs in which there is very little inlet pipe vacuum due to the higher load. The electric vacuum pump is actuated for a certain time. This ensures that the brake is sufficiently boosted when maneuvering. After a cold start, the DME will actuate the electric vacuum pump once only for max. 60 seconds. The electric vacuum pump is actuated in the following situations: Engine-running signal from DME Coolant temperature below 60°C The electric vacuum pump is a vane-cell pump.
- Throttle valve The throttle valve changes the cross-sectional area of the inlet pipe. This creates an inlet pipe vacuum behind the throttle valve, especially in overrun mode.
- DME or DDE: Digital engine electronics or digital diesel electronics The DME or DDE actuates the components needed for system functions (e.g. solenoid valves, electric switching valves, electropneumatic pressure converters).
The system functions of the vacuum system are described using the following examples
- Power assist for brakes
- Actuation of exhaust flaps
- Adjustment of variable turbine geometry
- Actuation of controlled damping mounts
- Exhaust gas recirculation
- Drawing off of blow-by gases from crankcase
- Blowing out activated charcoal filter
Power assist for brakes
The brake booster amplifies the force excerpted at the brake pedal. To do this, the brake booster stores part of the vacuum generated by the engine. The vacuum then amplifies the force generated by pressure on the brake pedal.
Actuation of exhaust flap
A controlled electropneumatic exhaust flap is fitted in the exhaust system. The exhaust flap enhances active sound damping. The exhaust flap is closed by vacuum.
Adjustment of variable turbine geometry
The variable turbine geometry controls the boost pressure via adjustable guide vanes. The guide vanes are actuated by vacuum.
Actuation of controlled damping mounts
In the basic setting, there is no vacuum at the control component. The bypass in the mount is closed. Hydraulic fluid flows back and forth through a ring channel between the upper and lower chambers in the mount. The mount acts like a conventional hydraulic bearing. The mount has hard damping.
If a vacuum is applied to the mount's control component, the bypass will open. The hydraulic fluid then flows back and forth between the chambers through a larger cross-sectional area. The mount has softer damping.
Exhaust gas recirculation
With exhaust gas recirculation, part of the exhaust gas is take from behind the exhaust manifold. This is then fed back into the engine through the intake air duct. The exhaust gas recirculation pipe is located at the inlet to the intake manifold.
If a vacuum is applied to the exhaust gas recirculation valve, the exhaust gas recirculation pipe will open. The level of vacuum is determined by the opening in the exhaust gas recirculation valve.
Exhaust gases flow through a connecting pipe to the exhaust manifold and into the intake manifold.
Drawing off of blow-by gases from crankcase
The crankcase ventilation system uses vacuum to bleed the blow-by gases out of the engine block. Blow-by gases are the small portion of the cylinder fill that passes by the piston rings and into the crankcase during compression. If the blow-by gases are not bled from the engine block through the crankcase ventilation system, they will accumulate in the crankcase. The blow-by gases would then apply pressure on the pistons from below. This would have a negative effect on the downward movement of the pistons in the intake stroke and operating stroke.
Blowing out activated charcoal filter
The fuel tank vent hose is connected to an activated charcoal filter. Vapors from the fuel tank are collected in the activated charcoal filter. The activated charcoal filter is connected to the intake manifold by a pipe. A fuel evaporation control valve is fitted in this pipe. When the fuel evaporation control valve is opened, the vacuum in the manifold draws in fresh air. At the same time, the fresh air blows out the fuel vapors collected in the activated charcoal filter.