Motronic

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Bosch Motronic was one of the first digital engine-management systems. The idea behind it was to fully integrate and regulate all major engine system parameters, thereby enabling fuel delivery and spark timing control functions to be controlled by the same unit, in an attempt to achieve optimum efficiency, driveability and power output potential.

The early Motronic systems integrated spark timing control with existing Jetronic fuel injection systems, such as L-Jetronic, LH-Jetronic, K-Jetronic, and in some cases Mono-Jetronic. It was originally developed and first used in the BMW 7 Series^[1], before being implemented on several Volvo [1] and Porsche engines throughout the 1980s.

The components of the Motronic 1.x systems for the most part remained unchanged during production, although there are some differences in certain situations. The electronic control unit (ECU) receives information regarding engine speed and position, crankshaft angle, coolant temperature and throttle position. A mass air flow meter is used to measure the mass of air entering the engine.

If the engine is supercharged a charge air temperature sensor monitors the temperature of the inducted air after it has passed through turbocharger and intercooler if installed, in order to suppress knocking.

A separate constant idle speed (CIS) system monitors and regulates base idle speed, depending if an interior electrical component is in operation. A cold start (5th) injector is used to provide extra fuel enrichment during different cold-start conditions.