![Bosch monopoint](https://upload.wikimedia.org/wikipedia/commons/f/f4/Bosch_monopoint.jpg)
Motronic is the trade name given to a range of digital
engine control unit
An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by re ...
s developed by
Robert Bosch GmbH
Robert Bosch GmbH (; ), commonly known as Bosch and stylized as BOSCH, is a German multinational engineering and technology company headquartered in Gerlingen, Germany. The company was founded by Robert Bosch in Stuttgart in 1886. Bosch is 9 ...
(commonly known as Bosch) which combined control of fuel injection and ignition in a single unit. By controlling both major systems in a single unit, many aspects of the engine's characteristics (such as power, fuel economy, drivability, and emissions) can be improved.
Motronic 1.x
Motronic M1.x is powered by various i8051 derivatives made by Siemens, usually SAB80C515 or SAB80C535. Code/data is stored in DIL or PLCC EPROM and ranges from 32k to 128k.
1.0
Often known as "Motronic basic", Motronic ML1.x was one of the first digital engine-management systems developed by
Bosch. These early Motronic systems integrated the spark timing element with then-existing
Jetronic Jetronic is a trade name of a manifold 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 variation ...
fuel injection technology. It was originally developed and first used in the
BMW 7 Series
The BMW 7 Series is a full-size luxury sedan manufactured and marketed by the German automaker BMW since 1977. It is the successor to the BMW E3 "New Six" sedan and is now in its seventh generation.
The 7 Series is BMW's flagship car and is on ...
, before being implemented on several
Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
and
Porsche
Dr. Ing. h.c. F. Porsche AG, usually shortened to Porsche (; see #Pronunciation, below), is a German automobile manufacturer specializing in high-performance sports cars, SUVs and sedans, headquartered in Stuttgart, Baden-Württemberg, Germany ...
engines throughout the 1980s.
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
A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...
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
Naturally may refer to:
;Albums
* ''Naturally!'', an album by Nat Adderley
* ''Naturally'' (Houston Person album)
* ''Naturally'' (J. J. Cale album)
* ''Naturally'' (John Pizzarelli album)
* ''Naturally'' (Sharon Jones album)
* ''Naturally'' ...
, an air temperature sensor is located in the air flow meter to work out the air mass. However, if the engine is
turbocharged
In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...
, 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
An intercooler is a heat exchanger used to cool a gas after compression. Often found in turbocharged engines, intercoolers are also used in air compressors, air conditioners, refrigeration and gas turbines.
Internal combustion engines
Mo ...
, in order to accurately and dynamically calculate the overall air mass.
;Main system characteristics:
*Fuel delivery, ignition timing, and
dwell angle
A contact breaker (or "points") is a type of electrical switch, found in the ignition systems of spark-ignition internal combustion engines. The switch is automatically operated by a cam driven by the engine. The timing of operation of the switch ...
incorporated into the same control unit.
*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
An oxygen sensor (or lambda sensor, where lambda refers to air–fuel equivalence ratio, usually denoted by λ) or probe or sond, is an electronic device that measures the proportion of oxygen (O2) in the gas or liquid being analysed.
It was ...
may be fitted (the system was originally designed for
leaded fuel
Tetraethyllead (commonly styled tetraethyl lead), abbreviated TEL, is an organolead compound with the formula Pb( C2H5)4. It is a fuel additive, first being mixed with gasoline beginning in the 1920s as a patented octane rating booster that al ...
).
1.1
Motronic 1.1 was used by BMW from 1987 on motors such as the
M20. This version was also used by Volvo from 1982-1989 on the turbocharged B23ET, B230ET and B200ET engines.
The systems have the option for a lambda sensor, enabling their use with catalytic converter-equipped vehicles. This feedback system allows the system to analyse exhaust emissions so that fuel and spark can be continually optimised to minimise emissions. Also present is adaptive circuitry, which adjusts for changes in an engine's characteristics over time. Some PSA engines also include a knock sensor for ignition timing adjustment,
perhaps this was achieved using an external Knock Control Regulator.
The Motronic units 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 camshaft 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.
In BMW vehicles, this Motronic version did not have a cylinder ID and as a result, both banks of injectors fired at once.
1.2
Motronic 1.2 is the same as 1.1, but uses a hot-film MAF in place of the flapper-door style AFM. This version was used by BMW on the S38B36 engine in the E34 M5 and on the M70B50 engine in the 750il from 1988 until 1990.
1.3
Motronic 1.1 was superseded in 1988 by the Motronic 1.3 system
[http://www.opel-scanner.com/files/DME_1.1_1.3.pdf ] that was also used by PSA on some XU9J-series engines (which previously used Motronic 4.1).
and by BMW.
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.
1.5
This system was used on some of General Motors engines (C20NE, 20NE, C20SE, 20SE, 20SEH, 20SER, C20NEF, C20NEJ, C24NE, C26NE, C30LE, C30NE, C30SE, C30SEJ, C30XEI...). The system is very reliable and problems encountered are usually caused by poor contact at the associated plug/socket combinations
that link the various system sensors to the Electronic Control Unit (ECU). Predecessor of the ME Motronic. Also used in the Opel engines C16SEI
1.5.2
Was used since 1991 in the Opel Astra F with C20NE engine. Major change was the use of a MAF instead of AFM in the Motronic 1.5.
1.5.4
Was used since 1994 in the Opel Omega B with X20SE engine. (Modified successor of C20NE engine) Major change to the Motronic 1.5.2 was the use of DIS ignition system, knock sensor and EGR valve. Was also used in the Opel engine X22XE.
M1.5.5
Used in Fiat/Alfa/Lancia and Opel vehicles.
1.7
The key feature of Motronic 1.7 is the elimination of an ignition distributor, where instead each cylinder has its own electronically triggered ignition coil. Motronic 1.7 family has versions 1.7, 1.7.2, 1.7.3, all of them used on M42/M43 engines in
BMW 3 Series (E36)
The third generation of the BMW 3 Series range of compact executive cars is designated under the model code E36, and was produced by the German automaker BMW from 1990 to 2000. The initial models were of the four-door sedan body style, followed ...
up to 1998 and
BMW 5 Series (E34)
The BMW E34 is the third generation of the BMW 5 Series, which was produced from November 2, 1987, until 1996. Initially launched as a sedan in January 1988, the E34 also saw a "Touring" station wagon (estate) body style added in September 1992 ...
up to 1995. The BMW M70 12 cylinder had the Motronic M1.7 and two distributors.
1.8
This system was used by
Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
on the B6304 engine used in the Volvo 960.
Motronic 2.x
Motronic M2.x is powered by various i8051 derivatives made by Siemens, usually SAB80C515 or SAB80C535.
2.1
The ML 2.1 system integrates an advanced engine management with 2 knock sensors, provision for adaptive fuel & timing adjustment, purge canister control, precision sequential fuel control and diagnostics (pre OBD-1). Fuel enrichment during cold-start is achieved by altering the timing of the main injectors based on engine temperature. The idle speed is also fully controlled by the digital Motronic unit, including fast-idle during warm-up. Updated variants ML 2.10.1 through 2.5 add MAF Mass Air Flow sensor logic and direct fire ignition coils per cylinder. Motronic 2.1 is used in the Porsche 4 cyl 16V 944S/S2/968 and the 6 cyl Boxer Carrera 964 & 993, Opel/Vauxhall, FIAT & Alfa Romeo engines.
2.3/2.3.2
The M2.3.2 system was made for Audi's turbo 20V 5-cylinder engines mainly, but a variant was also used on the Audi 32V 3.6L V8 and a few Audi 32V 4.2 V8 engines. The turbo 5 cylinder version was the first time knock and boost control had been introduced in one ECU, though the ECU was really two computers in one package. One side of the ECU controlled the timing and fueling while the other side controlled the boost and knock control. Each side has its own Siemens SAB80C535 processor and its own EPROM for storing operating data. What made this ECU special was the use of two crank sensors and one cam sensor. The ECU used one crank sensor to count the teeth on the starter ring for its RPM signal, and the other read a pin on the back of the flywheel for TDC reference. This ECU was first seen when the 20V turbo 5-cylinder engine (RR Code) was installed into the Audi Quattro. It was then used in the Audi 200 20V turbo until 1991 when the Audi S4 was introduced and the ECU received several upgrades, including migration from a distributor-based ignition to coil on plug sequential ignition and an added overboost function. This ECU ended in 1997 when the last Audi S6 rolled off the assembly line. This ECU was also used in the legendary Audi RS2 Avant.
The V8 version of the ECU was only single processor based while retaining all the same features of the turbo 5-cylinder ECU less the boost control. The 3.6 V8 version had a distributor-based ignition system and was upgraded around the same time to coil on plug as its 20V turbo counterpart in 1992–1993.
2.5
Was introduced in 1988 in the Opel Kadett E GSi 16V C20XE engine. Sequential fuel injection and knock control.
2.7
Late '80s and early '90s, various Ferrari. Some Opel / Vauxhall (C20LET engine).
2.8
Successor of the Motronic 2.5. Was used from 1992 at Opel C20XE engine. Major change was the introduction of DIS ignition. Was also at Opel V6 engine C25XE (1993, Opel Calibra (also X25XE), Opel Vectra A) used. Modified as M2.8.1 (1994) for X30XE and X25XE (Opel Omega B). M2.8.3 engine X25XE (Opel Vectra B) and X30XE (Opel Sintra).
Motronic 3.x
Motronic M3.x is powered by i196 microcontroller with code in flash memory ranging from 128kB to 256kB.
3.1
Compared with ML1.3, this system adds knock sensor control, purge canister control and start-up diagnostics. Motronic 3.1 is used in non-
VANOS
VANOS is a variable valve timing system used by BMW on various automotive petrol engines since 1992. The name is an abbreviation of the German words for ''variable camshaft timing'' (german: variable Nockenwellensteuerung).
The initial version ...
BMW M50B25 engines.
3.3
Motronic 3.3 is used by BMW M60B30/B40 V8's in the 5, 7 & 8 series.
3.3.1
Motronic 3.3.1 is used in
BMW M50B25 engines with VANOS.
3.7
Motronic 3.7 is used in the
Alfa Romeo V6 engine in the later 12 valve 3.0L variants, replacing the
L-Jetronic Jetronic is a trade name of a manifold 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 variation ...
.
3.7.1
Motronic 3.7.1 is used in the
Alfa Romeo V6 engine in the 24 valve variants.
3.8.1, 3.8.2, 3.8.3, 3.8.4
Motronic M3.8x is used in many Volkswagen/Audi/Skoda vehicles
Motronic 4.X
Motronic M4.x is powered by various i8051 derivatives made by Siemens.
40.0
??
40.1
??
4.1
The Motronic ML4.1 system was used on
Opel
Opel Automobile GmbH (), usually shortened to Opel, is a German automobile manufacturer which has been a subsidiary of Stellantis since 16 January 2021. It was owned by the American automaker General Motors from 1929 until 2017 and the PSA Grou ...
/
Vauxhall
Vauxhall ( ) is a district in South West London, part of the London Borough of Lambeth, England. Vauxhall was part of Surrey until 1889 when the County of London was created. Named after a medieval manor, "Fox Hall", it became well known for ...
eight-valve engines from 1987 to 1990,
[http://www.opel-scanner.com/files/Opel_MotronicML4.1.pdf ] Alfa Romeo and some
PSA Peugeot Citroën
The PSA Group (), legally known as Peugeot S.A. (Peugeot Société Anonyme, trading as Groupe PSA; formerly known as PSA Peugeot Citroën from 1991 to 2016) was a French multinational automotive manufacturing company which produced automobiles ...
XU9J-series engines.
Fuel enrichment during cold-start is achieved by altering the timing of the main injectors based on engine temperature, no "cold start" injector is required. The idle speed is also fully controlled by the Motronic unit, including fast-idle during warm-up (therefore no thermo-time switch is required).
The ML4.1 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
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. 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.
There is 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 ML4.1 was used in the Opel engines: 20NE, 20SE, 20SEH, 20SER, C20NE, C30LE, C30NE.
4.3
The Motronic 4.3 was used by
Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
for their five-cylinder turbocharged
850
''For codepage, see CP850.''
__NOTOC__
Year 850 ( DCCCL) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar.
Events
By place
Europe
* February 1 – King Ramiro I dies in his palac ...
models from 1993 until 1996.
It was introduced with the launch of the ''850 Turbo'' (also called the ''850 T-5'' and ''850 T-5 Turbo'') in October 1993 for model year 1994. Features included OBD I diagnostics, dual knock sensors and a lot more. For the 1996 model year OBD II diagnostics were introduced on some cars while M4.3 was beginning to be phased out. The last M4.3 equipped cars were made for model year 1997.
4.4
The Motronic 4.4 was used by
Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
from 1996 until 1998.
The M4.4 was based on its predecessor and featured only a small number of improvements. Memory capacity was doubled and a few new functions were introduced such as immobilizer compatibility. OBD II was standard on all cars fitted with this system albeit the necessary protocols were not integrated for all markets.
The system was used for the five- and six-cylinder modular engined cars and was used on turbocharged and naturally aspirated models. Introduced in 1996 for 1997 model year it was first installed on some of the last
850
''For codepage, see CP850.''
__NOTOC__
Year 850 ( DCCCL) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar.
Events
By place
Europe
* February 1 – King Ramiro I dies in his palac ...
models
[ like the 2.5 20V and AWD. A coil on plug variant existed for the six cylinder ]Volvo 960
The Volvo 900 Series is a range of executive cars produced by the Swedish manufacturer Volvo Cars from 1990 to 1998. The 900 Series was introduced in 1990 to replace the 700 Series from which it derived. Prior to the end of its production, the ...
/S90/V90.[ After the 850 was replaced by the ]Volvo V70
The Volvo V70 is an executive car manufactured and marketed by Volvo Cars from 1996 to 2016 across three generations.
The name ''V70'' combines the letter ''V'', standing for ''versatility'', and ''70'', denoting relative platform size (i.e., a ...
, Volvo S70
The Volvo S70 is a compact executive car produced by Volvo Cars from 1996 to 2000. The S70 was essentially a facelifted 850 saloon. The S70 was replaced with the Volvo S60.
Overview
Introduced in Europe in late 1996 for the 1997 model year and ...
and Volvo C70
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
the system was used until the end of model year 1998.
4.6
The Motronic 4.6 was used in Nissan Micra K11 from 2000 until 2003.
Motronic 5.X
5.2
Motronic 5.2 was used in the BMW M44B19 engine. Compared to 1.7, Motronic 5.2 has OBD-II capability and uses a hot-wire MAF sensor in place of the flapper-door AFM.
5.2.1
Motronic 5.2.1 was used in Land Rover Discovery Series II and P38 Range Rovers that were built starting with late 1999. It was only used in cars equipped with V8 gasoline engines. This variant of the engine management system was adapted for off-road use. Unlike the Motronic system in BMW sedans, that uses a chassis accelerometer to differentiate between misfires and rough road, the Land Rover version used signal from ABS control unit to detect rough road conditions. This version of the system was integrated with body control module and anti-theft system.
See also
* Digifant Engine Management system
*Jetronic Jetronic is a trade name of a manifold 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 variation ...
References
External links
Bosch.com
official website
Motronic 1.1/1.3 information
{{Bosch
Fuel injection systems
Embedded systems
Power control
Engine technology
Automotive technology tradenames
Robert Bosch GmbH