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Integrating Electronic Control Modules (ECM) and Electronic Control Units (ECU) in EVs

What is an electronic control module?

If we liken an electric vehicle (EV) to the human body, we can say that the battery performs the function of the heart, providing the necessary supply of power for the car to run. If this is so, then the electronic control module, interchangeably referred to as the electronic control unit, acts as the vehicle’s brain.

What are its functions?

As the vehicle’s brain, the function of the ECM/ECU is to facilitate and optimize its specific systems, covering operation, safety and overall performance. The ECU keeps track of numerous factors, such as engine performance, emissions, transmission, braking, among many others. 

ECUs do this by gathering information from sensors strategically positioned in the vehicle, and make real-time decisions that impact efficiency of fuel consumption, emissions reduction, safety, and the driving experience. They are also responsible for various vehicle subsystems’ communication that results in better integration and reliability. 

How were ECUs integrated into electric vehicles?

ECUs were already extant back in the 1960s, during which time electronic controls in vehicles were being introduced. The ECU was developed initially for specific functions such as electronic ignition timing. Later, in the 1970s, ECUs were pushed further to the forefront due to tighter regulations on emissions.

Called “Engine Control Module”, the ECM was originally developed to regulate engine performance and emissions. In later decades, the ECU was increasingly used to manage things like fuel injection and ignition timing, shifting more from the mechanical to electronic control. Additional sensors and on-board diagnostic (OBD) systems too, were introduced.

In the 2000s and beyond, ECUs were innovated to handle safety systems and more advanced features, thanks to software-based vehicles. They were designed to manage functions relating to advanced driver assistance systems (ADAS), information and entertainment systems, and connectivity. Most recently, ECUs are essential in the operation of self-driving vehicles, particularly in sensor fusion and decision-making.

What are some ECUs present in modern vehicles?

The number of ECUs that can be found in a car depends on its make, model, and complexity level. Some cars can have up to 150 ECUs, each designed for a specific function. Below we will find some essential types of ECUs:

  • Engine Control Unit
    This is one of the most important ECUS in any car, as it controls the operation of the engine, fuel injection, ignition timing, and emissions control.
  • Transmission Control Unit
    This ECU manages transmission-related functions such as gear shifting in order to provide peak performance and smoothness while driving.
  • Anti-lock Braking System Control Unit
    This manages the anti-lock braking system, which stops wheels from locking up when braking, providing stability and vehicle control.
  • Airbag Control Module
    This controls when and where airbags and other supplemental restraint systems (SRS) are deployed should a collision occur, by using sensor data.
  • Body Control Module
    This control unit handles functions such as lighting, power windows, door locks, and climate control.
  • Climate Control Module
    This ECU manages the car’s heating, ventilation, and air conditioning (HVAC). It ensures passenger comfort, by optimizing temperature, fan speed, and air distribution.
  • Infotainment Control Module
    This ECU is in charge of the vehicle’s multimedia and entertainment systems, such as the radio, touchscreen interface, navigation, and connectivity.
  • Hybrid/Electric Vehicle Control Unit
    This control unit takes care of the hybrid car or the electric vehicle’s powertrain, battery charging, regenerative braking, and other functions. 

The ECUs listed above are only a few of many control modules that EVs contain. Others include but are not limited to: Electronic Stability Control, Powertrain Control Module, Steering Control Module, and Adaptive Cruise Control Module.

ECUs of the future

Electronic control units or modules are vital to the automotive industry. They allow vehicles to perform optimally, safely, and efficiently. In the coming years, together with the advancement of electric vehicles, they will be used to deploy advanced driver assistance systems, as well as autonomous vehicles. 


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