The great revolution in car electronics: The software-defined vehicle

Anyone who studies the transformation of the automotive industry will inevitably come across the term "software-defined vehicle" (SdV). Software is by no means new in automotive engineering. It has played an important role since the 1980s, initially in engine control units and ABS systems, and later also in assistance and infotainment systems. Even conventional vehicles contain millions of lines of program code.

So what's so special about software-defined vehicles? How do they differ from previous car generations? And what do their owners gain from them? To answer these questions, we spoke with Michael Hörig, who is responsible for central technology and development strategy at Bosch Mobility. He's the ideal person to address this topic—as the world's largest automotive supplier, Bosch is actively shaping the transition to software-defined vehicles.

According to Hörig's observations, development in the past was indeed more hardware-oriented. Software was a necessary component for getting an ESP control unit, for example, to work. Such control units were developed with customized software and delivered to the car manufacturers as a package. Over 100 of these specialized microcomputers were used in top-of-the-line models. Subsequent functional expansion was out of the question, as this would have required the development of new hardware with adapted programs.

Today, new functions are often created using software, which requires a completely different design of the electronic components. Instead of dozens of individual control units, software-defined vehicles rely on a few powerful central computers. These control a multitude of tasks, reducing hardware complexity and facilitating the integration of new programs. Most manufacturers use two to five such computers, which combine entire functional areas – so-called domains. Examples of such domains include the drivetrain, assistance systems, infotainment, and the chassis, steering, and braking systems.

The transition also leads to a separation of hardware and software. This makes it possible to develop and update software independently of the computer running it. This allows the vehicle to be continuously improved or its functionality expanded even after purchase.

An operating system is required to connect the software applications (apps) to the domain computers. Some automakers develop their own operating systems, but many rely on existing systems such as Android Automotive. Bosch has already made this transition: 40,000 developers at Bosch Mobility are employed, among other things, to program apps and operating systems – including for hardware from other manufacturers.

Another key feature of the software-defined vehicle is its connectivity to the manufacturer's cloud. Cars can receive software updates wirelessly via a cellular connection ("over the air" - OTA), similar to what's available on smartphones. These updates range from bug fixes and security patches to completely new features.

This also makes it clear what car owners get out of the new electronic architecture. The ability to install additional functions via updates is certainly one of the biggest advantages. Attractive examples of this include unlocking additional engine power and installing additional infotainment and feature apps. These can even extend to new functions for matrix LED headlights, which then beam warning messages onto the road.

The control of multiple individual systems by a domain computer also allows for more in-depth interventions in a car's setup. Today's driving modes only allow for minor adjustments, such as shock absorber stiffness or steering assistance. As an example of the new freedom, Hörig cites the "Vehicle Motion System" developed by Bosch, which allows extensive adjustment of driving behavior. Take ESP, for example: While the stability program previously had to prevent the vehicle from skidding solely through braking interventions, the new system can also control the steering itself.

This requires a "steer-by-wire" system that transmits steering commands via a data line. This means the driver no longer directly senses the position of the wheels. This allows for more powerful interventions and can simultaneously give the car a much more agile character. The Vehicle Motion System is expected to go into production soon, but Bosch has not yet revealed which model it will be in.

Bosch's "Connected Map Services," on the other hand, are already integrated into millions of vehicles. These combine swarm data from connected vehicles with environmental information on weather, wrong-way drivers, or traffic jams. This creates a comprehensive situational overview that goes far beyond what the driver or the on-board sensors can detect. This allows warnings to be issued much earlier, long before a vehicle reaches a dangerous location.

Another example of the benefits of software-defined vehicles is Bosch's "Battery in the Cloud" service. This service optimizes the performance and service life of batteries in electric vehicles. Battery data such as state of charge, temperature, and driving style are continuously transmitted to the cloud and analyzed there using artificial intelligence. This not only allows for a precise assessment of the current battery condition but also enables the creation of customized charging profiles to counteract cell aging.

To be prepared for future functional enhancements, vehicles must already have reserves of computing power at the start of production, even if they aren't needed initially. Otherwise, the central computers will become increasingly slower with each update or will be unable to process larger programs at all. In Hörig's experience, dimensioning these reserves is an important coordination process between automakers and their suppliers like Bosch.