Technical characteristics of the digital engine management system «Motronic M 2.5» (Opel Kadett E)

The "20XE" engine uses the digital engine management system "Motronic M 2.5" from Bosch, which is a further development of the system "Motronic ML 4.1" (see above). The differences of the "Motronic M 2.5" system are as follows:

• the controller generates commands to control fuel injection, ignition timing and knock elimination selectively for each cylinder;
• injection nozzles open sequentially in accordance with the order of operation of the cylinders, i.e. fuel is supplied only to the cylinder where the piston is in the intake stroke;
• a mass air flow meter is used, which is a hot-wire sensor that measures the mass of air entering the engine. The intake air flow passes a heated conductor. By regulating the electric current passing through this conductor, its excess temperature is maintained constant relative to the temperature of the incoming air. The magnitude of the required heating current of the conductor is a measure of the mass of air entering the engine intake system. This current is converted into a voltage signal, which is processed by the controller to determine the engine load along with information about the crankshaft speed;
• the system includes a knock sensor. Based on signals from the sensor, the controller generates commands to change the ignition timing in the direction of delay or advance separately for each cylinder, and also self-adjusts to work with gasoline with an octane rating of 98 to 95;
• to ensure selective operation of the system, in addition to the speed sensor and crankshaft position, an induction generator sensor of the moment of spark formation in the first cylinder is used. It sends a signal to the controller about the location of the piston of the first cylinder at the top dead center of the end of the compression stroke. The sensor is installed in the ignition distributor;
• the crankshaft speed and position sensor is installed on the cylinder block next to the oil dipstick socket opposite a special toothed rim pressed onto the crankshaft;
• the position type throttle position sensor has been replaced with a resistive type sensor;
• the fuel pressure regulator is installed directly on the fuel line.

Below are data on the components of the "Motronic M 2.5" system that differ from those described for the system "Motronic ML 4/1"

[Original article on the web portal: OPELBOOK]