When you sit back and think about the physical mechanisms that allow a carburetor to operate an internal combustion engine, you can visualize how the electronic fuel injection control system works! Intake manifold and fuel pressure are directly linked to how much fuel is ready to enter that cylinder -- the same physical properties that allow fuel to exit the carburetor.
Without the control system, electric vehicles (EVs) would not be operational to the extent that they are.
EVs were commercially available before the horseless carriage and before electronic controllers! Control systems, even sophisticated ones, existed well before electronics and software made them the incredible systems they are today. It’s those mechanically based control systems that will help us understand the “invisible” systems that will turn a technician into an invaluable technician.
Electronic fuel injection (EFI), whether that is a glorified electronic carburetor or a sophisticated multipoint, multi-pulsed direct injection fuel delivery system, is the control system technicians have been using since EFI and electronic control units (ECUs) -- aka engine control units -- became the computer system of choice for mechanics across the globe.
The biggest difference between sophisticated engine control systems and the control systems in an EV is the immediate mechanical feedback. The engine won’t start, the transmission won’t shift, the engine runs rough, and so on.
EVs have systems that are periodically used, like preparation for direct current fast charging (DCFC), used every time the vehicle is powered up or on a condition-dependent recurring basis, like regenerative braking.
Regenerative braking has the added benefit of removing the human response delay when it comes to an emergency braking situation. In the event of emergency braking, regen may begin the moment the driver lifts off the accelerator only if specific conditions are met: The vehicle is equipped with regenerative braking, the battery state of charge allows it to activate, the vehicle speed is within the allowable range, and, if equipped, the system is manually turned on.
If all the conditions are met, then emergency braking just got a few milliseconds better! If not, then emergency braking remains the same as a conventional vehicle.
Being able to visualize how a control system works is an invaluable skill for a technician to learn and can mean the difference between a well-paid technician and a replaceable robot.
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