Motronic
Encyclopedia
Motronic is the trade name given to a range of digital engine-management systems developed by Robert Bosch GmbH
, commonly known as Bosch.
. The basic idea behind the system 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. These early Motronic systems integrated the spark timing element with then-existing Jetronic
fuel injection technology.
It was originally developed and first used in the BMW 7-Series, before being implemented on several Volvo
and Porsche
engines throughout the 1980s. It was also used on turbocharged Audi Quattro
models during the early 1990s.
The components of the Motronic ML1.x systems for the most part remained unchanged during production, although there are some differences in certain situations. The engine control module (ECM) receives information regarding engine speed, crankshaft
angle, coolant temperature and throttle position. An air flow meter also measures the volume of air entering the induction system.
If the engine is naturally aspirated, an air temperature sensor is located in the air flow meter to work out the air mass. However, if the engine is turbocharged, an additional charge air temperature sensor is used to monitor the temperature of the inducted air after it has passed through the turbocharger and intercooler
, in order to accurately and dynamically calculate the overall air mass.
main system characteristics:
/ Vauxhall
eight-valve engines from 1987–1990, and some PSA Peugeot Citroën
XU9J-series engines.
The ECM software controls fuel enrichment during cold-start by altering the timing of the main injectors based on engine temperature, no 5th injector is required. The idle speed is also fully controlled by the ECM, including fast-idle during warm-up (no thermo-time switch is required).
The 4.1 system did not include provision for a knock sensor for timing adjustment. The ignition timing and fuel map could be altered to take account of fuels with different octane rating
s by connecting a calibrated resistor (taking the form of an "octane coding plug" in the vehicle's wiring loom) to one of the ECU pins, the resistance depending on the octane adjustment required. With no resistor attached the system would default to 98 octane.
The ECM has a single output for the injectors, resulting in all injectors firing simultaneously. The injectors are opened once for every revolution of the engine, injecting half the required fuel each time.
The Motronic 1.1 and 1.3 systems are largely similar, the main improvement being the increased diagnostic capabilities of Motronic 1.3. The 1.3 ECM can store many more detailed fault codes than 1.1, and has a permanent 12-volt feed from the vehicle's battery which allows it to log intermittent faults in memory across several trips. Motronic 1.1 can only advise of a few currently-occurring faults.
The systems include a knock sensor for ignition timing adjustment and the option for a lambda sensor, enabling their use with catalytic converter-equipped vehicles.
The ECMs have 2 injection outputs, and the injectors are arranged in 2 "banks" which fire once every two engine revolutions. In an example 4-cylinder engine, one output controls the injectors for cylinders 1 and 3, and the other controls 2 and 4. The system uses a "cylinder ID" sensor mounted to the cam-shaft to detect which cylinders are approaching the top of their stroke, therefore which injector bank should be fired. During start-up (below 600 RPM), or if there is no signal from the cylinder ID sensor, all injectors are fired simultaneously once per engine revolution.
Robert Bosch GmbH
Robert Bosch GmbH is a multinational engineering and electronics company headquartered in Gerlingen, near Stuttgart, Germany. It is the world's largest supplier of automotive components...
, commonly known as Bosch.
Motronic ML1.x
Motronic ML1.x was one of the first digital engine-management systems developed by BoschRobert Bosch GmbH
Robert Bosch GmbH is a multinational engineering and electronics company headquartered in Gerlingen, near Stuttgart, Germany. It is the world's largest supplier of automotive components...
. The basic idea behind the system 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. These early Motronic systems integrated the spark timing element with then-existing Jetronic
Jetronic
Jetronic is a trade name of an fuel injection technology for automotive petrol engines, developed and marketed by Robert Bosch GmbH from the 1960s onwards. Bosch licensed the concept to many automobile manufacturers. There are several variations of the technology offering technological development...
fuel injection technology.
It was originally developed and first used in the BMW 7-Series, before being implemented on several Volvo
Volvo
AB Volvo is a Swedish builder of commercial vehicles, including trucks, buses and construction equipment. Volvo also supplies marine and industrial drive systems, aerospace components and financial services...
and Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
engines throughout the 1980s. It was also used on turbocharged Audi Quattro
Audi Quattro
The Audi Quattro is a road and rally car, produced by the German automobile manufacturer Audi, now part of the Volkswagen Group. It was first shown at the 1980 Geneva Motor Show on 3 March.The word quattro is derived from the Italian word for "four"...
models during the early 1990s.
The components of the Motronic ML1.x systems for the most part remained unchanged during production, although there are some differences in certain situations. The engine control module (ECM) receives information regarding engine speed, crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
angle, coolant temperature and throttle position. An air flow meter also measures the volume of air entering the induction system.
If the engine is naturally aspirated, an air temperature sensor is located in the air flow meter to work out the air mass. However, if the engine is turbocharged, an additional charge air temperature sensor is used to monitor the temperature of the inducted air after it has passed through the turbocharger and intercooler
Intercooler
An intercooler , or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through nearly isobaric cooling, which removes...
, in order to accurately and dynamically calculate the overall air mass.
main system characteristics:
- Fuel delivery, ignition timing, and dwell angle incorporated into the same ECM.
- Crank position and engine speed is determined by a pair of sensors reading from the flywheel.
- Separate constant idle speed system monitors and regulates base idle speed settings.
- 5th injector is used to provide extra fuel enrichment during different cold-start conditions. (in some configurations)
- Depending on application and version, an oxygen sensor may be fitted (the system was originally designed for leaded fuel).
- No knock sensor.
Motronic 4.1
The Motronic 4.1 system was used on OpelOpel
Adam Opel AG, generally shortened to Opel, is a German automobile company founded by Adam Opel in 1862. Opel has been building automobiles since 1899, and became an Aktiengesellschaft in 1929...
/ Vauxhall
Vauxhall
-Demography:Many Vauxhall residents live in social housing. There are several gentrified areas, and areas of terraced townhouses on streets such as Fentiman Road and Heyford Avenue have higher property values in the private market, however by far the most common type of housing stock within...
eight-valve engines from 1987–1990, and some PSA Peugeot Citroën
PSA Peugeot Citroën
PSA Peugeot Citroën is a French manufacturer of automobiles and motorcycles sold under the Peugeot and Citroën marques. Headquartered in the 16th arrondissement of Paris, PSA is the second largest automaker based in Europe and the number eight in the world.-History:In December 1974 Peugeot S.A....
XU9J-series engines.
The ECM software controls fuel enrichment during cold-start by altering the timing of the main injectors based on engine temperature, no 5th injector is required. The idle speed is also fully controlled by the ECM, including fast-idle during warm-up (no thermo-time switch is required).
The 4.1 system did not include provision for a knock sensor for timing adjustment. The ignition timing and fuel map could be altered to take account of fuels with different octane rating
Octane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
s by connecting a calibrated resistor (taking the form of an "octane coding plug" in the vehicle's wiring loom) to one of the ECU pins, the resistance depending on the octane adjustment required. With no resistor attached the system would default to 98 octane.
The ECM has a single output for the injectors, resulting in all injectors firing simultaneously. The injectors are opened once for every revolution of the engine, injecting half the required fuel each time.
Motronic 1.1 & 1.3
The Motronic 1.1 System was used by BMW from 1987. This was then superseded in 1988 by the Motronic 1.3 system that was also used by PSA on some XU9J-series engines (which previously used Motronic 4.1).The Motronic 1.1 and 1.3 systems are largely similar, the main improvement being the increased diagnostic capabilities of Motronic 1.3. The 1.3 ECM can store many more detailed fault codes than 1.1, and has a permanent 12-volt feed from the vehicle's battery which allows it to log intermittent faults in memory across several trips. Motronic 1.1 can only advise of a few currently-occurring faults.
The systems include a knock sensor for ignition timing adjustment and the option for a lambda sensor, enabling their use with catalytic converter-equipped vehicles.
The ECMs have 2 injection outputs, and the injectors are arranged in 2 "banks" which fire once every two engine revolutions. In an example 4-cylinder engine, one output controls the injectors for cylinders 1 and 3, and the other controls 2 and 4. The system uses a "cylinder ID" sensor mounted to the cam-shaft to detect which cylinders are approaching the top of their stroke, therefore which injector bank should be fired. During start-up (below 600 RPM), or if there is no signal from the cylinder ID sensor, all injectors are fired simultaneously once per engine revolution.