Today cars, trucks and heavy equipment integrate numerous electronic subsystems, such as combustion engine controllers, electric motor controllers, and transmission controllers. Electronics and semiconductors have become so essential that the US government has established a program to reshore micro circuit fabrication and strengthen supply chain. Following the supply chain failure caused by covid-19, in 2022 the US enacts the “CHIPS and Science Act (CHIPS)” which will generate investments of over USD$600 billion between2022 and 2032.The act did address the semiconductor manufacturing but also many adjacent domains such as Research and Development (R&D), Workforce Development, Supply Chain Security, Technological Leadership, Economic and National Security, Public-Private Partnerships, Incentives and Grants, and International Collaboration.
As we see in the following figure, published by Deloitte, the proportion of electronics in vehicle is growing from a few percent in the70’s to an expected 50% around 2030.
All this to say that electronics represent an important portion of the total cost of the vehicle. As we will see in the next few pages there are a lot of different electronic items in vehicles.
The remainder of this article enumerates most of the electronic circuits or modules found in vehicles, discuss related technologies and then overview standards and safety requirements. Demonstrating the great importance of electronics in vehicle manufacturing.
There are many kinds of electronic systems in vehicles, they are listed and classified in six categories in the following sections. These categories are:
1. Controllers
2. Sensors
3. Actuators
4. Communication Networks
5. User Interface Components
6. Specific to electric vehicle
Controllers are made with an MCU and many other components to interface sensors, actuators and to communicate with other controllers located in the vehicle. In very simple vehicles there could be only one controller taking care of all the necessary functions while in more complex vehicles each controller has a specific task. Here is a list of controllers find in various type and class of vehicle: ECU (engine control unit), TCU (transmission control unit), BCM (body control module), VCU (vehicle control unit), BMS (battery management system), ABS (Anti-lock Braking System), ESC (Electronic Stability Control), ADAS (Advanced Driver Assistance Systems), TPMS (Tire Pressure Monitoring System), EPS (Electric power steering), etc.
According to ARM there are over 100MCUs in modern and luxurious vehicles.
CAN is generally used for inter-controller communications.
LIN is used to control peripherals such as power windows, mirrors, seats.
Flex Ray which provides deterministic timeslot is used for time critical functions such as drive-by-wire, active suspension, braking system, adaptive cruise control.
Some variations of Ethernet such as 100BASE-T1 are also used in automotive for higher speed required by the newer controller and for infotainment, think of video transmission.
Dashboards are mostly made of LCD (liquid crystal Display),LED (Light emitting diode) all driven by an MCU.
Head-Up Displays are made with special apparatus to project light on a reflecting part of the windshield. One of the technologies used is the digital micro mirrors which are an array of millions of small mirrors, each one pivoting in a position to reflect the ray or not.
Voltage Sensors are used to measure battery output terminals voltage, to measure individual battery cells voltage, etc.
Current Sensors are used to measure the battery output terminals current, to measure the parallel cells strings current, etc.
Rotor Angle Sensors are used to detect the rotor angle, this value is used by the electric motor controller to properly drive the electric motor.
Battery Impact Detector ensures detecting impacts which may reduce the battery life or cause the battery to become defective either notworking as expected or causing treat such as catching fire. Some impact will just be logged and used to estimate the battery aging, while larger impact may trigger warning to the driver for servicing the car.
Microcontrollers ICs for real-time control, music and video playing. All controllers in a car have one or more MCU.
Interfaces ICs such as CAN BUS, LIN, Ethernet, LVDS, etc. Mostly used for inter-controller communication and control peripherals such as windows and door locks.
SiC Power MOSFET are the technology permitting to develop highly efficient converter using resonant topologies. These converters can be on-board battery chargers, inverters or DCDC converters. On-board battery chargers are necessary to allow cars to be connected to domestic AC power for low power charging. Inverters convert the traction battery DC voltage to three-phase AC power for the electric propulsion motors. DCDC converters are used to convert traction battery DC voltage to accessories voltage such as 12V or 24V. The traction battery DC voltage is between 400V to 900V.
Battery Management ICs are specialized integrated circuit monitoring and stabilizing the cells in a battery.
Data Converter ICs such as analog to digital converter are used to digitalize signals from voltage sensors, current sensors, temperature sensors, video signals, etc. Digital to analog converter permits MCU to drive signals to control motor speed, light intensity, etc.
Digital Light Processor ICs are made by Texas Instruments and are used for head-up display. They are made of micro mirrors, each one moving in real-time to reflect the light forming the image.
Motor Driver ICs are used as example to drive seat actuators, to windows motors, etc.
Wireless Connectivity ICs provide connectivity with Bluetooth, Wi-Fi, GPS, etc.
Single chip Radar ICs implement radar used for parking assistance and warning indicator.
Hall Effect Sensors ICs are used to count the metal gear teeth for measuring speed and position, they can be used to detect the presence of lock for safety purposes.
Magnetic field sensor ICs are used to measure earth magnetic field providing the car orientation relative to north pole.
There are so many other types of IC used in vehicles, the list above is a subset, there are many others such as: Angle Sensor, Light Sensor, Temperature, Humidity, Audio Amplifier, Power management, clock and timing, logic, switch and multiplexer.
Lead-Acid battery type is by far the most common in conventional vehicles providing 12 or 24V to start the vehicle, provide power to the many controllers and sensors and power accessories.
The Lithium-Ion battery type is the one mostly use in electric vehicle today, but there are other ones such as Nickel-Metal Hydride, Lithium-Ion Polymer, Lithium-Sulfur, Sodium-Ion, etc. We never know, soon the Lithium-Ion may be supplanted by newer technology.
Ultracapacitors are not really batteries, but they are often connected in parallel with battery to provide large current peak capability during acceleration and breaking, thus reducing the requirements for the battery. This is possible because ultracapacitors have a much lower impedance than batteries.
The vehicle market is regulated by many agencies and standards, some of them are listed here:
· Canada
o Canadian Motor Vehicle Safety Standards (CMVSS)
o Canadian Environmental Protection Act (CEPA)
o Corporate Average Fuel Consumption (CAFC)
· USA
o National Highway Traffic Safety Administration (NHTSA)
o Federal Motor Vehicle Safety Standards (FMVSS)
o Environmental Protection Agency (EPA)
o Corporate Average Fuel Economy (CAFE)
o Federal Motor Carrier Safety Administration (FMCSA)
On the international side a safety standard is becoming more and more important as it guides not just the end-product but also the development processes which include system, material and software aspects. Itis the ISO 26262 having the title “Road vehicles – Functional safety”.
The “Automotive Electronics Council” is especially addressing the electronic for automotive in terms of reliability and testing methods. Many ICs are qualified as per AEC-Q100 and passive as per AEC-Q200 so that they can be used for automotive.
Electronics, including semiconductors, passives, printed circuit boards, have a major role and consist of a large portion of the production cost in automotive, many information sources claim there are over thousand ICs in a car. With so many ICs the reliability has become a serious issue to make the car reliable and safe; standards such as AEC-Q100 andISO-26262 address this.
It should also be mentioned that all the MCU within the car have their own software, so today electronics and software form an unavoidable pair for the automotive industry.
