DM 3.1 Features

DME 3.1 New Features:

The M50 is the first engine to use the latest Digital Motor Electronics management system designated DME 3.1. The control unit size has been reduced to occupy 40% less space than previous DME 1.3 control units.

The M50 control unit contains two computers instead of one:

- an 8 bit computer (for fuel injection only); and
- a 16 bit computer (main computer).

DME 3.1 can process more information considerably faster in the same period of time than DME 1.3.

The extended functions of the DME 3.1 control unit, i.e., six individual output stages for the fuel injection and six for the ignition system, calls for a control unit with 88 pins.
In comparison to DME 1.3 the number of items in the diagnostic system have been greatly increased. Up to 30 malfunctions can be memorized, with an automatic scale of priorities according to the importance of the fault. Workshop personnel can obtain a readout of the stored data with the Service Tester or MODIC.

All data values needed to ensure correct and reliable engine operation are accompanied by substitute values, so that in the event a fault should develop, i.e., a missing input to the control unit, an emergency run program allows the vehicle to be driven to the nearest BMW Dealership for repairs.
Fully sequential injection is used for the first time on the M50 engine. All six injectors are controlled separately through six individual output stages in the Motronic Control Unit in contrast to semi-sequential fuel injection (M42, M30, M70) which meters fuel to pairs or groups of cylinders only.

Fully-sequential fuel injection means that conditions at every cylinder are ideal for the formation of a precisely controlled and correct fuel-air mixture.