Comparative analysis of the evolution of electronic and electrical architectures of mainstream car companies

The core technology of future automotive products is the electronic and electrical architecture. The automotive electronic and electrical architecture is gradually developing from decentralized and embedded to centralized and integrated. The ultimate ideal state should be to form a central brain (one brain) for the car to manage various functions in a unified manner. The electronic and electrical architecture is similar to the "central government", which can coordinate the management of various functions of the car to avoid "divided power and inconsistent government orders". At the beginning, the "central government" may manage less, and the "local princes" will still have a certain degree of control, but later the "central government" will definitely manage more and more, and eventually local administrative agencies will only receive instructions from the "central government" and execute them efficiently to ensure the best overall performance of the vehicle.

In the past, the controllers on cars were independent of each other, and the software was embedded, so the whole car only needed to be integrated with the final hardware. In the future, as the ECU is relieved of its burden, the previously highly decentralized functions will be integrated into the domain controller, and the OEM must master the central control system itself, otherwise it will lose control of its automotive products. And gradually integrating and unifying the originally highly decentralized control functions is a new compulsory course for traditional car companies, so car companies' mastery of electronic and electrical architecture is step-by-step and progressive. Tesla Model 3 has ushered in a major change in electronic and electrical architecture, with the emergence of a central computing prototype + location domain, shortening the vehicle wiring harness by 50%, and the future goal is to reduce the vehicle wiring harness to 100 meters. In terms of electronic architecture, Tesla is more than 6 years ahead of traditional car companies. Except for Tesla, the electronic and electrical architecture of most car companies is still in the early functional domain controller stage, that is, some functions are concentrated in the functional domain controller, but more distributed modules are still retained, that is, the transitional solution of "distributed ECU + domain controller" to avoid additional risks and costs due to excessive changes. The next-generation cross-domain integrated electronic and electrical architecture planned by most companies will be mass-produced in 2022 to achieve a high degree of software concentration in domain controllers and gradually reduce distributed ECUs. By 2025, some car companies will implement the electronic and electrical architecture of central computing + regional controllers, thereby achieving further integration of software and hardware, and the ownership of software will gradually be returned to the OEM. The process of evolving towards the "central computing + regional control" architecture may take up to 5-10 years.

The pace of evolution of electronic and electrical architecture of mainstream car companies varies. Source: Automotive Electronics Design

1. Audi A8 Trial

The Audi A8 launched in 2018 was the first to realize the integrated control of assisted driving functions, replacing the distributed assisted driving system with separate ECUs. In addition to the integration of the autonomous driving domain, the other four major domains of chassis + safety, power, body, and entertainment still adopt a distributed architecture. Its autonomous driving domain controller consists of 4 chips. Mobileye EyeQ3 is responsible for visual perception computing, such as traffic signal recognition, pedestrian monitoring, collision alarm, lane line recognition, and light detection. NVIDIA K1 is responsible for image fusion computing, such as driver monitoring and image processing of 360 panoramic cameras. Intel Cyclone V is responsible for target fusion, map fusion, parking assistance, and pre-brake lights. Infineon's Aurix TC297 is responsible for communication processing. The software development of this autonomous driving domain controller was completed by the Austrian software company TTTech, and Delphi provided hardware integration.

2018 Audi A8 domain controller, source: Audi

2. Tesla Model 3 starts a comprehensive transformation of electronic and electrical architecture

Tesla is a comprehensive reformer of automotive electronic and electrical architecture. In 2012, Model S had a relatively clear functional domain division, including power domain, chassis domain, and body domain. The ADAS module spanned the power and chassis domains. Since the traditional domain architecture cannot meet the development of autonomous driving technology and the needs of software-defined cars, in order to decouple software and hardware and install a more powerful main control chip, the electronic and electrical architecture must be changed first. Therefore, the Model 3 launched by Tesla in 2017 broke through the framework of functional domains and realized the central computing + regional controller framework. By building a heterogeneous fusion architecture + autonomous software platform, it not only realized software-defined cars, but also effectively reduced the cost of the whole vehicle and improved efficiency. 1) The three controllers of the Model 3 effectively reduce the material cost; 2) Hardware integration is software, providing a foundation for in-depth control and maintenance of the car; 3) The autonomous software platform supports expansion and reuse through modularization. Tesla Model 3 has basically realized the prototype of a centralized architecture, but Model 3 is still quite far from a true centralized architecture: the communication architecture is mainly based on the CAN bus, and the central computing module only formally integrates the audio and video entertainment MCU, the autonomous driving FSD, and the in-vehicle and out-of-vehicle networking modules on a board, and each module independently runs its own operating system. But in any case, Model 3 has implemented the electronic and electrical architecture concept framework of central computing + regional control, leading traditional car companies by about 6 years. The essence behind the evolution of the electronic and electrical architecture of Tesla's three generations of cars is the process of constantly taking vehicle functions back from suppliers for independent development. Model 3's autonomous driving module, entertainment control module, other regional controllers, and thermal management are all independently designed and developed, realizing the autonomy of the main modules of the whole vehicle, without relying on Tier 1. Even if there is no independent module, Tesla has also conducted joint development with suppliers. For example, Tesla added its own software to the ibooster provided by Bosch, and shortened the braking distance through software updates. Through the evolution of three models, Tesla's new electronic and electrical architecture has not only achieved a significant reduction in the number of ECUs and a significant shortening of wiring harnesses (MODEL S wiring harness is 3,000 meters, Model 3 is reduced by more than half), but also broke the old parts supply system of the automotive industry (that is, the deep coupling of software and hardware is packaged and sold to the OEM, the OEM has poor bargaining power, and subsequent function adjustments are difficult), and truly realized software-defined cars. Tesla's OTA can change the braking distance, open seat heating, and provide personalized user experience. Due to the breakthrough of the functional domain, Tesla's domain controller spans the body, cockpit, chassis and power domain, which makes the vehicle's functional iteration more flexible, and users can experience that the car is often used and always new. In sharp contrast, most traditional car manufacturers' OTA is limited to functions such as in-vehicle infotainment. In order to better play the role of software, Tesla has achieved self-development and self-production of the most core intelligent hardware, the main control chip for autonomous driving (Tesla believes that the dedicated design of the chip makes the software on it run more efficiently), which means that the upgrade speed and function deployment of subsequent Tesla vehicles will no longer rely on external SOC chip suppliers, and the soul of the vehicle will truly be in its own hands.

The evolution history of Tesla's electronic and electrical architecture, source: Huang Shaotang "Software Defines Cars, Architecture Defines Software" The four controllers of the Model 3 vehicle include the central computing module (CCM), the left body control module (BCM LH), the right body control module (BCM RH) and the front body control module (BCM FH). The left body control module is responsible for the convenience control of the left body as well as steering, braking, power assistance, etc. The right body control module is responsible for the convenience control of the right body, chassis safety system, power system, thermal management, etc. The central computing module includes the autonomous driving module, the infotainment module, and the communication connection inside and outside the car, sharing a set of liquid cooling systems. The autonomous driving and entertainment control module takes over the sensors related to assisted driving - cameras and millimeter-wave radars, and puts the intelligent driving and infotainment with high computing power requirements together, which facilitates the continuous upgrading of intelligent hardware. In 2019, Tesla launched its self-developed FSD chip to replace the NVIDIA Drive PX2 chipset, and the AI ​​computing performance was improved by 21 times. As Tesla has developed the most core computing hardware for autonomous driving, Tesla has greatly improved its leading advantage over its competitors. The operating system is customized based on open source Linux, and the company uses self-developed middleware. Both software and hardware are independently controllable, which accelerates the iteration and update of vehicle function and reduces the cost of vehicle development.