Bosch Motronic was one of the first series-produced 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 order to achieve optimum efficiency, driveability and power output potential. The early Motronic systems integrated spark timing control with existing 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
[25 years of Bosch Motronic: Think tank under the bonnet, Bosch, may 2004], before being implemented on several Volvo and Porsche engines throughout the 1980s.
The components of the Motronic system for the most part remained unchanged during production, although there are some differences in some situations. The control unit (ECU) receives information regarding engine speed, crankshaft position, air flow into the induction system, coolant temperature and throttle position. The temperature of the inducted air after it has passed through the turbocharger and the intercooler is also measured. A signal relay informs the control unit if an interior electrical component is in operation, necessitating a rise in idle speed. A cold start injector is used to provide extra fuel enrichment during starter motor operation.