Tesla's wiring harness and controller iterations

When talking about electronic and electrical architecture, I think an interesting thought is: with the popularization of the next generation of smart cars, during the iteration of domain control systems and wiring harness designs, how will the number of cables and electrical connections other than EE components change?

Following this line of thinking, I looked up Tesla's Part List and Wiring Diagram to explore the evolution of the vehicle wiring harness assembly and the changes in value:

● I mainly targeted the homemade domain controllers, homemade core controllers and powertrain domain controllers (2+4+4=10), to count which MCUs and low-voltage connectors were used.

● Then count the connectors and ECUs used by external controllers - this part is similar to other car manufacturers, so it seems there are 7-8 at present

Figure 1. The whole vehicle with controls and main connectors

● The entire 12V cable mainly includes:

12V battery harness, instrument panel and console harness, door and trunk harness, front bumper and front end harness, roof harness, main front and body harness, rear bumper and subframe harness, seat belt and windshield harness, and in the Model 3 cm there is also a list of coaxial and special cables.

Figure 2. Overview of the 12V wiring harness of the Tesla Model 3

Part 1 Tesla’s Domain Controller

Tesla's design is developed with the main control domain controller (infotainment and Autopilot) and components such as power distribution and left and right body controllers.

● Central computing module

Mainly includes: infotainment system, assisted driving system and vehicle gateway communication system; the gateway is divided into three CAN (backbone network) of Private CAN, Vehicle CAN and Chassis CAN

● Private CAN

Customized, connecting 6 core self-made controllers (infotainment/Autopilot, electric drive module, VCR controller, left and right body controllers) and several core external components chassis steering power, brake (I-booster+ESP) and airbag controller. These are Tesla's core systems, carrying the most basic information interaction of functional modules such as vehicle safety, drive, chassis control, etc.

● Vehicle CAN

Connects self-made components (three major body controllers), high-voltage management module, VSC (Security Controller) and external components such as electric compressor and steering information to realize traditional body domain functions (load control, air conditioning, owner entry and exit) and high-voltage management

● Chassis CAN

The most traditional one is connected to tire pressure, braking, steering, airbags, etc. Tesla should consider this aspect as a safety consideration

Of course, these are the main communication connections, which are distributed on the communication interface of this controller. My understanding is that Tesla has gradually compressed ECUs from non-essential external suppliers. In fact, we can no longer see pure ECUs. They are all mechatronics or electronic control units with safety functions.

▲Figure 3. Connection of instrument panel wiring harness

The following Figure 4 is more meaningful, because in fact this controller mainly needs to connect to relatively high-speed interfaces such as external video sensor interfaces. Since this aspect is developing rapidly, with the increase of screen interfaces, cameras and lidars, the focus of the increase is on this part.

▲Figure 4. Coaxial and special cables

Part 2 Tesla's three main controllers

This part has a lot of content, I will start with the introduction today, and expand on the interfaces and chips of each component tomorrow. Let's take a look again. The three integrated controllers actually integrate many functions, which have been explained before.

▲Figure 5. Tesla’s three core self-made integrated controllers and three-section wiring harness

● The front body module is responsible for the 12V battery, power distribution and thermal management functions. As shown in the wiring harness below, since it is in the front of the car body, the wipers, front trunk, external lights and air conditioning are all placed inside. We will sort out the wiring harness connection and functional block diagram tomorrow. It has been iterated to Gen3

Figure 6. Model Y’s money control module

● The left body control module focuses on the functions of lighting and entry in the traditional body domain. The air conditioning system includes the blower motor drive distribution. My understanding is that the control is configured nearby where the load is. This controller has been iterated to Gen3

Figure 7. Model Y’s L BCM

● The right body control module is mainly responsible for air conditioning, windows, internal and external lights, parking, parking assist signal collection and other functions. It also includes some sensor signal collection and load drive of the air conditioning system, as well as some high-mounted brake lights, position lights and left and right reverse light drives, etc. It has been iterated to Gen3

Figure 8. Model Y’s R BCM

summary:

I have been thinking recently that as Tesla has been iterating for generations in terms of chips, functional design, software and production, we really need to think about how this will disrupt traditional automotive electronics. We need to connect all the information, see what car companies are doing, how Tier 1 companies can cooperate with such car companies, and what core opportunities there will be.