Jetronic
Encyclopedia
Jetronic is a trade name of an fuel injection
technology for automotive petrol engine
s, 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 and refinement.
) is measured using a pressure sensor located in the intake manifold, in order to calculate the duration of the fuel injection pulses. Originally, this system was just called Jetronic, but the name D-Jetronic was later created as a retronym
to distinguish it from the newer versions.
pressurises the fuel up to approximately 5 bar
(72.5 psi
). The air that is taken in is also weighed - to determine the amount of fuel to inject. Commonly called 'Continuous Injection System' (CIS) in the USA. This system has no lambda
loop or lambda control. K-Jetronic debuted in the 1973.5 Porsche 911
T, and was later installed into a number of Porsche
, Peugeot
, Mercedes-Benz
, Volkswagen Group
, Ferrari
, BMW
, Volvo
, Saab
, Datsun
and Ford automobiles.
lambda control, also named Ku-jetronic, the letter u denominates The USA. The system was developed to comply with Californian exhaust emission regulations, and later replaced by KE-Jetronic. First introduced in the Volvo 265 in 1976.
(ECU) may be either analog or digital, and the system may or may not have closed-loop lambda control. Commonly known as 'CIS-E' in the USA. The later KE3 (CIS-E III) variant features knock
sensing capabilities.
(ECU) than the D-Jetronic's.
L-Jetronic was used heavily in 1980s
-era Europe
an cars. Licensing some of Bosch's L-Jetronic concepts and technologies, Lucas, Hitachi Automotive Products
, NipponDenso
, and others produced similar fuel injection systems for Asian car manufacturers. Despite physical similarity between L-Jetronic components and those produced under license by other manufacturers, the non-Bosch systems should not be called L-Jetronic, and the parts are usually incompatible.
of air into the engine. This air mass meter
is called HLM2 (Hitzdraht-LuftMassenmesser 2) by Bosch. The LH-Jetronic was mostly used by Scandinavia
n car manufacturers, and by sports and luxury cars produced in small quantities, such as Porsche 928
. The most common variants are LH 2.2, which uses an Intel 8049 (MCS-48) microcontroller, and usually a 4 kB
programme memory, and LH 2.4, which uses a Siemens
80535 microcontroller (a variant of Intel's 8051/MCS-51 architecture) and 32 kB programme memory based on the 27C256 chip. LH-Jetronic 2.4 has adaptive lambda control, and support for a variety of advanced features; incincluding fuel enrichment based on exhaust gas temperature (ex. Volvo B204GT/B204FT engines). Some later (post-1995) versions contain hardware support for first generation diagnostics according to ISO 9141 (a.k.a. OBD-II) and immobiliser functions. The 1995 and newer Volvo 940 vehicles are one such example.
Mono-Jetronic is different from all other known single-point systems, in that it only relies on a throttle position sensor for judging the engine load. There are no sensors for air flow, or intake manifold vacuum. Mono-Jetronic always had adaptive closed-loop lambda control, and due to the simple engine load sensing, it is heavily dependent on the lambda sensor for correct functioning.
The ECU uses an Intel 8051
microcontroller
, usually with 16 kB of program memory and usually no advanced diagnostics.
Fuel injection
Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....
technology for automotive petrol engine
Petrol engine
A petrol engine is an internal combustion engine with spark-ignition, designed to run on petrol and similar volatile fuels....
s, developed and marketed by Robert Bosch GmbH
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...
from the 1960s onwards. Bosch licensed the concept to many automobile manufacturers
Automotive industry
The automotive industry designs, develops, manufactures, markets, and sells motor vehicles, and is one of the world's most important economic sectors by revenue....
. There are several variations of the technology offering technological development and refinement.
D-Jetronic (1967–1976)
Analog fuel injection. The 'D' is an abbreviation from , which means pressure. The depression (vacuumVacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
) is measured using a pressure sensor located in the intake manifold, in order to calculate the duration of the fuel injection pulses. Originally, this system was just called Jetronic, but the name D-Jetronic was later created as a retronym
Retronym
A retronym is a type of neologism that provides a new name for an object or concept to differentiate the original form or version of it from a more recent form or version. The original name is most often augmented with an adjective to account for later developments of the object or concept itself...
to distinguish it from the newer versions.
K-Jetronic (1973–1993)
Mechanical fuel injection. The 'K' stands for , meaning continuous. This is different from pulsed injection systems, in that the fuel flows continuously from all injectors, while the fuel pumpFuel pump
A fuel pump is a frequently essential component on a car or other internal combustion engined device. Many engines do not require any fuel pump at all, requiring only gravity to feed fuel from the fuel tank through a line or hose to the engine...
pressurises the fuel up to approximately 5 bar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...
(72.5 psi
Pounds per square inch
The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...
). The air that is taken in is also weighed - to determine the amount of fuel to inject. Commonly called 'Continuous Injection System' (CIS) in the USA. This system has no lambda
Oxygen sensor
An oxygen sensor, or lambda sensor, is an electronic device that measures the proportion of oxygen in the gas or liquid being analyzed. It was developed by the Robert Bosch GmbH company during the late 1960s under the supervision of Dr. Günter Bauman...
loop or lambda control. K-Jetronic debuted in the 1973.5 Porsche 911
Porsche 911
The Porsche 911 is a luxury 2-door sports coupe made by Porsche AG of Stuttgart, Germany. It has a distinctive design, rear-engined and with independent rear suspension, an evolution of the swing axle on the Porsche 356. The engine was also air-cooled until the introduction of the Type 996 in 1998...
T, and was later installed into a number of 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....
, Peugeot
Peugeot
Peugeot is a major French car brand, part of PSA Peugeot Citroën, the second largest carmaker based in Europe.The family business that precedes the current Peugeot company was founded in 1810, and manufactured coffee mills and bicycles. On 20 November 1858, Emile Peugeot applied for the lion...
, Mercedes-Benz
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
, Volkswagen Group
Volkswagen Group
Volkswagen Group is a German multinational automobile manufacturing group. , Volkswagen was ranked as the world’s third largest motor vehicle manufacturer and Europe's largest....
, Ferrari
Ferrari
Ferrari S.p.A. is an Italian sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari in 1929, as Scuderia Ferrari, the company sponsored drivers and manufactured race cars before moving into production of street-legal vehicles as Ferrari S.p.A. in 1947...
, BMW
BMW
Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...
, 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...
, Saab
Saab
Saab AB is a Swedish aerospace and defence company, founded in 1937. From 1947 to 1990 it was the parent company of automobile manufacturer Saab Automobile, and between 1968 and 1995 the company was in a merger with commercial vehicle manufacturer Scania, known as Saab-Scania.-History:"Svenska...
, Datsun
Datsun
Datsun was an automobile marque. The name was created in 1931 by the DAT Motorcar Co. for a new car model, spelling it as "Datson" to indicate its smaller size when compared to the existing, larger DAT car. Later, in 1933 after Nissan Motor Co., Ltd...
and Ford automobiles.
K-Jetronic (Lambda)
A variant of K-Jetronic with closed-loopControl theory
Control theory is an interdisciplinary branch of engineering and mathematics that deals with the behavior of dynamical systems. The desired output of a system is called the reference...
lambda control, also named Ku-jetronic, the letter u denominates The USA. The system was developed to comply with Californian exhaust emission regulations, and later replaced by KE-Jetronic. First introduced in the Volvo 265 in 1976.
KE-Jetronic (1985–1993)
Electronically controlled mechanical fuel injection. The engine control unitEngine control unit
An engine control unit is a type of electronic control unit that determines the amount of fuel, ignition timing and other parameters an internal combustion engine needs to keep running...
(ECU) may be either analog or digital, and the system may or may not have closed-loop lambda control. Commonly known as 'CIS-E' in the USA. The later KE3 (CIS-E III) variant features knock
Engine knocking
Knocking in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.The...
sensing capabilities.
L-Jetronic (1974–1989)
Analog fuel injection. L-Jetronic was often called Air-Flow Controlled (AFC) injection to further separate it from the pressure-controlled D-Jetronic — with the 'L' in its name derived from , meaning air. In the system, air flow into the engine is measured by a movable vane (indicating engine load) known as the mass air flow sensor (MAF) — referred to in German documentation as the LuftMassenMesser or LMM. L-Jetronic used custom-designed integrated circuits, resulting in a simpler and more reliable engine control unitEngine control unit
An engine control unit is a type of electronic control unit that determines the amount of fuel, ignition timing and other parameters an internal combustion engine needs to keep running...
(ECU) than the D-Jetronic's.
L-Jetronic was used heavily in 1980s
1980s
File:1980s decade montage.png|thumb|400px|From left, clockwise: The first Space Shuttle, Columbia, lifted off in 1981; American President Ronald Reagan and Soviet leader Mikhail Gorbachev eased tensions between the two superpowers, leading to the end of the Cold War; The Fall of the Berlin Wall in...
-era Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an cars. Licensing some of Bosch's L-Jetronic concepts and technologies, Lucas, Hitachi Automotive Products
Hitachi, Ltd.
is a Japanese multinational conglomerate headquartered in Marunouchi 1-chome, Chiyoda, Tokyo, Japan. The company is the parent of the Hitachi Group as part of the larger DKB Group companies...
, NipponDenso
DENSO
is a global automotive components manufacturer headquartered in the city of Kariya, Aichi Prefecture, Japan. Established December 16, 1949 as , in 1996 the company became DENSO Corporation worldwide...
, and others produced similar fuel injection systems for Asian car manufacturers. Despite physical similarity between L-Jetronic components and those produced under license by other manufacturers, the non-Bosch systems should not be called L-Jetronic, and the parts are usually incompatible.
LE1-Jetronic, LE2-Jetronic, LE3-Jetronic (1981–1991)
This is a simplified and more modern variant of L-Jetronic. The ECU was much cheaper to produce due to more modern components, and was more standardised than the L-Jetronic ECUs. The connections between AFM and ECU are simplified. Three variants of LE-Jetronic exist: LE1, the initial version. LE2 (1984–), featured cold start functionality integrated in the ECU, which does not require the cold start injector and thermo time switch used by older systems. LE3 (1989–), featuring miniaturised ECU with hybrid technology, integrated into the junction box of the AFM.LU-Jetronic (1983–1991)
The same as LE2-Jetronic, but with closed-loop lambda control. Initially designed for the US market.LH-Jetronic (1982–1998)
Digital fuel injection, introduced for California bound 1982 Volvo 240 models. The 'LH' stands for - the hotwire anemometer technology used to determine the massMass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
of air into the engine. This air mass meter
Mass flow sensor
A mass air flow sensor is used to find out the mass flowrate of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit to balance and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts...
is called HLM2 (Hitzdraht-LuftMassenmesser 2) by Bosch. The LH-Jetronic was mostly used by Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
n car manufacturers, and by sports and luxury cars produced in small quantities, such as Porsche 928
Porsche 928
The Porsche 928 was a sports-GT car sold by Porsche AG of Germany from 1978 to 1995. Originally intended to replace the company's iconic 911, the 928 attempted to combine the power, poise, and handling of a sports car with the refinement, comfort, and equipment of a luxury sedan to create what some...
. The most common variants are LH 2.2, which uses an Intel 8049 (MCS-48) microcontroller, and usually a 4 kB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
programme memory, and LH 2.4, which uses a Siemens
Siemens AG
Siemens AG is a German multinational conglomerate company headquartered in Munich, Germany. It is the largest Europe-based electronics and electrical engineering company....
80535 microcontroller (a variant of Intel's 8051/MCS-51 architecture) and 32 kB programme memory based on the 27C256 chip. LH-Jetronic 2.4 has adaptive lambda control, and support for a variety of advanced features; incincluding fuel enrichment based on exhaust gas temperature (ex. Volvo B204GT/B204FT engines). Some later (post-1995) versions contain hardware support for first generation diagnostics according to ISO 9141 (a.k.a. OBD-II) and immobiliser functions. The 1995 and newer Volvo 940 vehicles are one such example.
Mono-Jetronic (1988–1995)
Digital fuel injection. This system features one centrally positioned fuel injection nozzle. In the US, this kind of single-point injection was marketed as 'throttle body injection' (TBI, by GM), or 'central fuel injection' (CFI, by Ford).Mono-Jetronic is different from all other known single-point systems, in that it only relies on a throttle position sensor for judging the engine load. There are no sensors for air flow, or intake manifold vacuum. Mono-Jetronic always had adaptive closed-loop lambda control, and due to the simple engine load sensing, it is heavily dependent on the lambda sensor for correct functioning.
The ECU uses an Intel 8051
Intel MCS-51
The Intel MCS-51 is a Harvard architecture, single chip microcontroller series which was developed by Intel in 1980 for use in embedded systems. Intel's original versions were popular in the 1980s and early 1990s. While Intel no longer manufactures the MCS-51, binary compatible derivatives remain...
microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
, usually with 16 kB of program memory and usually no advanced diagnostics.