The eight-cylinder is reliably supplied with lubricant in all driving situations by two volume flow-controlled pendulum shift cell pumps consistently providing exactly the right amount of oil required by the engine. This is ensured by a change in eccentricity (off-centre arrangement) of the inner rotor in the pump versus the pump housing as a function of oil pressure in the main oil duct.
In consideration of the physical forces and loads encountered in an extremely dynamic driving situation, it is conceivable that when the driver applies the brakes particularly hard, for example, the supply of oil to the oil sump serving as an interim storage reservoir would not be sufficient, particularly as the oil sump is positioned behind the front axle subframe for reasons of space. So if the worst came to the worst, lubrication would be interrupted completely. This is however prevented by the concept of "optimum-dynamic wet sump lubrication", a system with two oil sumps: a small oil sump in front of the front axle subframe and a large oil sump behind the first one. A separate recirculation pump draws oil from the small oil sump at the front under all conditions and feeds the oil to the larger sump at the rear. The larger sump, in turn, is carefully sealed off in order to avoid any splash losses and the formation of foam.
The new eight-cylinder power unit from BMW M also comes with electronic oil level control determining the level of oil by means of a sensor fitted in the oil sump. The data thus measured is transmitted by a serial databus to the engine management evaluating this data by means of various algorithms. The value thus obtained, corrected by the car's lateral and longitudinal acceleration, is then presented to the driver in the instrument cluster.
Eight individual throttle butterflies with electronic management.
In motorsport this is standard technology, in "regular" cars it is quite rare - the use of a separate, individual throttle butterfly for each cylinder. But precisely this mechanically very sophisticated system is unsurpassed in giving the engine a spontaneous response and supreme performance. And precisely that is what counts in a BMW M Car.
The power unit of the BMW M3 so closely related to motorsport comes with eight individual throttle butterflies, four butterflies on each row of cylinders being driven by one actuator in an electronically controlled process. To provide this precise electronic management, the position of the gas pedal is scanned by a touch-free hall potentiometer 200 times a second and evaluated immediately, the engine management registering any change in the position of the pedal and adjusting the individual throttle butterflies accordingly via the two actuators in an instantaneous, split-second process.
As a result, it takes the throttle butterflies only 120 milliseconds to reach their maximum opening point - about as long as a routined driver needs to press down the gas pedal. The result, first, is a sensitive and smooth response of the engine at low engine speeds and, second, an immediate, direct reaction of the car whenever the driver calls up more power from the engine. ...next page >>