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History

Analog, digital, connected

A look back at Bosch automotive electronics

Calibration of the Motronic digital engine management system at the Automotive Engineering Center in Schwieberdingen, 1984

It began with a visionary idea: Bosch applied for its first patent for an electronics product — an ignition unit for engines that was controlled using electronic tubes — over 100 years ago. However, the idea never got off the ground, as shaking during use damaged the tubes. As so often, the first step was the hardest.

The success story did not start for Bosch until some 60 years ago, with semiconductor technology that made it possible to use electronics in cars. Their engineering and production was challenging, but these electronic helpers have made technology more reliable, powerful, and affordable. Without semiconductors and electronics, Bosch would not be the global player it is today. But the road to get there was a rocky one.

Why would a company get involved in a line of business that no one at the company really knows much about and in which no one has any practical experience? At Bosch, the reason to do so was actually quite simple: the hope was that semiconductor components, which were cutting-edge at the time, would make it possible to build new and appealing products while increasing the reliability of automotive technology and decreasing the need for maintenance or repairs.

Making cars better from the ground up was a tempting vision for the future. But because Bosch had to buy semiconductor components that were developed for consumer electronics, it faced the fundamental question of how to ensure the necessary reliability for the tough conditions in a vehicle. In a television, semiconductor technology does not have to withstand everything from Arctic cold to scorching heat — but under the hood of a car it does.

Gotthold Zielasek, the inventor of the first semiconductor element manufactured by Bosch, 1954
Gotthold Zielasek, the inventor of the first semiconductor element manufactured by Bosch, 1954

Faced with this reality, Bosch decided in the 1950s to start developing semiconductor elements for cars itself and to engineer them from the start to take on the challenging conditions found in motor vehicles. Bosch applied for its first semiconductor patent in 1958 — for a semiconductor diode used in an alternator regulator. As Bosch’s strengths had traditionally been the manufacturing of high-quality mechanical products, the patent application marked a major step in the company’s reinvention. Building up a broad base of expertise within the company, however, remained a challenge.

“Attracting the bright sparks away from the semiconductor companies was simply impossible. There was no literature, either. So we had to study patent specifications.”
Electronics pioneer Karl-Ernst Boeters on Bosch’s first steps in the field of IC technology

Yet expertise was what the company needed, especially for the development of application-specific integrated circuits (ASICs) for cars starting in the mid-1960s. Because vehicle electronics are exposed to particularly demanding mechanical and climatic conditions, integrated circuits have a decisive advantage: they make it possible to combine hundreds of functions in a single component, significantly reducing the risk that individual functions might fail. To make sure it had access to sound semiconductor products, Bosch decided to set up its own production facilities rather than relying on suppliers.

Electronics were uncharted territory for automotive industry customers, meaning that Bosch could not rely solely on suppliers to ensure quality. The launch of a new technology was at stake. The use of electronic components in alternators and ignition systems was followed by more sophisticated electronics such as gasoline injection, which involves gaining control over complex processes that meter the amount of fuel going to the engine depending on the current conditions so that it functions optimally while keeping emissions and fuel consumption low.

Karl-Ernst Boeters, a pioneer in the development of integrated circuits for cars, at a microscope at the Bosch research center in Berlin, 1965
Karl-Ernst Boeters, a pioneer in the development of integrated circuits for cars, at a microscope at the Bosch research center in Berlin, 1965
“The first electronic components definitely proved their worth, so it just made sense for Bosch to start working on electronic control units.”
Volkmar Denner, chairman of the board of management
Assembling a printed circuit board for an electronic control unit at the Reutlingen plant, 1978
Assembling a printed circuit board for an electronic control unit at the Reutlingen plant, 1978

The Jetronic electronic gasoline injection system was an important milestone on the road to success for automotive electronics. Launched in 1967, the technology bore the stamp of future Bosch CEO Hermann Scholl and made it possible to comply with strict emission standards, acting as a blueprint for future developments.

During this era, Bosch manufactured increasingly sophisticated electronics and built a manufacturing plant for semiconductor-based electronics in Reutlingen, establishing an in-house supplier in 1974 that would become today’s Automotive Electronics division.

Integrated circuit (IC) for the L-Jetronic electronic gasoline injection system, 1975
Integrated circuit (IC) for the L-Jetronic electronic gasoline injection system, 1975

Analog electronics, with hundreds of individual components in a control unit and the combination of multiple functions in integrated circuits, was followed by digital electronics, with programmable memory and microprocessors, in the 1970s. Around this time, a consensus started to emerge regarding the necessity of a wide range of electronic functions for cars as a central pillar of any future strategy. However, the traditional circuit board technology, with soldered components, proved to be a weakness. When expensive cars break down on the road, it puts automakers in a difficult situation and has the potential to damage the reputation of suppliers such as Bosch. Hybrid technology – which features functions that have been fired onto a ceramic substrate and provides far greater reliability and a longer service life despite using significantly more complex manufacturing technology – offered a solution to that problem.

“The customer wants quality, and quality simply means that it works and will always work.”
Ulrich Goebel, former head of development for hybrid technology
Engineering a hybrid electronic control unit using computer-aided development (CAD), 1983
Engineering a hybrid electronic control unit using computer-aided development (CAD), 1983

In 1979, Bosch began producing its first digital engine control system that controlled both ignition and fuel injection at the same time. Motronic, as it was known, marked a breakthrough in engine management. As the first automotive system that was necessary for driving, Motronic featured a freely programmable control unit. The software enabled flexibility and could be adapted to allow the use of the same control unit in a different model, ushering in the age of the computer in the automobile. Starting in the late 1970s, Bosch increasingly focused on developing systems aimed at preventing accidents or mitigating their consequences. The ABS antilock braking system from 1978 is an example of this undertaking, as is the Bosch airbag control unit, which entered production in 1980. The ESP electronic stability program was even able to keep a vehicle on course when drivers were about to lose control.

Testing a 150mm silicon wafer that can be used to make hundreds of microchips, 1999
Testing a 150mm silicon wafer that can be used to make hundreds of microchips, 1999

With airbags, ABS, and Motronic on board, the company had to start looking for ways to connect each electronic system with the next to ensure smooth interaction between the separate control units despite the miles of wiring found in a car. It also had to make sure their functions were coordinated and properly orchestrated.

In the 1980s, the company therefore started thinking about a standardized data protocol for information transmission in cars, leading to the launch of the controller area network (CAN) in 1991. The CAN enabled the fast and precise exchange of information between sensors, electronic control units, and actuators – such as valves or switches — while still allowing the entire system to prioritize the activation of essential safety functions such as ESP within milliseconds to prevent the car from skidding, for example.

“Suddenly we had to write software. You had a completely different freedom, different dimensions for design, which was already a huge step.”
Siegfried Dais, former deputy chairman of the Bosch board of management
MEMS sensors in a hand, 2017
MEMS sensors in a hand, 2017

Another element also plays a role in ensuring that electronics function optimally: sensors. First developed in the late 1980s, microelectromechanical sensors (MEMS), were a milestone in this field. Bosch used the innovative breakthrough in automotive technology. These tiny helpers, some just 1.5 millimeters in size and equipped with moving parts, paved the way for Bosch to become the market leader in automotive sensors. One major advantage is that MEMS can be manufactured using a procedure similar to electronic switches. Both products are applied a thousand times over to a large silicon wafer in a sophisticated photochemical process and then split up into the individual components, known as chips or microchips. For MEMS, Bosch developed an innovative plasma etching production process that makes it possible to precisely form the tiny movable structures. Known as the “Bosch process,” it has since become the global standard in microelectronics.

“Microelectronics need some type of sensory organs to be able to perceive the environment.”
Jiri Marek, lead engineer for the first MEMS sensors
Bosch supplies automakers with power electronics, including electric motors for use as original equipment, 2020
Bosch supplies automakers with power electronics, including electric motors for use as original equipment, 2020

Resting on the shoulders of the technical solutions developed at Bosch in the field of automotive electronics over the past 60 or so years are many future driving scenarios that would have been virtually unthinkable just a decade ago but are now reality in some cases. Among them are self-driving cars that can independently use the web to share data with other vehicles — all with the goal of preventing accidents, reducing traffic jams, and saving energy.

Even in the future, physical electronics will remain the technical basis for web-based mobility solutions, with connected control units, sensors, and actuators. They will also form the foundation for artificial intelligence, which makes it possible for electronic systems to learn and helps conserve resources and prevent accidents.

“Bosch’s success story should encourage us to push ahead with new technologies and take risks — just like back then, when Bosch entered the field of automotive electronics.”
Volkmar Denner, chairman of the Bosch board of management

See and hear reports from time witnesses in developing electronics

Dietrich Kuhlgatz

Since 1998 I have been at Bosch. I am deputy head of the Historical Communications department, working as spokesperson and researcher. I am in charge of product history requests, take care of contacts to technology and transportation museums, and I am in charge of history-related topics in Asia Australia, and Africa.
Before joining Bosch, I studied in history and philosophy at Universities of Konstanz and Hamburg. After graduating, I was editor of a scientific journal and research associate at Deutsches Technikmuseum Berlin.

Picture of Dietrich Kuhlgatz

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