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How Computers and Chips Control Your Car’s Emissions

How Computers and Chips Control Your Car’s Emissions

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Modern cars can easily have one hundred million lines of code in their computers, controlling everything from acceleration to connectivity to the braking system. That also includes the emission control systems.

But how exactly do they do that?

Types of Emission Control Systems

There are several different systems to control emissions throughout your car:

  • Catalytic Converter: Metal in the convertor acts as a catalyst to change emissions to be less harmful.
  • Positive Crankcase Ventilation (PCV) System: Captures and returns vapors from the crankcase to the combustion chamber.
  • Exhaust Gas Recirculation (EGR) System: Some exhaust is pumped back into the combustion chamber to keep nitrogen oxides low.
  • Evaporative Controls: Prevents gasoline fumes from exiting the gas tank or fuel system.
  • Fuel and Air Injection: Reduces the hydrocarbons by controlling the combustion to be more efficient.

Why They Need to Be Computer Controlled

In order to control emissions correctly, the emission control systems have to be carefully monitored. For example, the PCV system should only allow a small amount of vapors back into the combustion chamber when the car’s idling, but more can be put in when the car’s running at a higher speed.

All of the other systems, especially the fuel injection system, need to be just as precisely controlled and constantly adjusted. Before the rise of fuel injection instead of carburetors, any of these systems would be calibrated for a rough average. Modern electronic control systems allow emission control systems to achieve greater efficiency and prevent more emissions.

How Software Can Cheat Emissions Tests

Emissions tests and requirements have been a part of legislation since the passage of the Clean Air Act in 1970. In order to comply with many of these emissions tests and still give customers enough power, car manufacturers have had to come up with a variety of systems.

Before computers were standard in cars, fooling the emission tests required special equipment. The rise of more advanced software, however, has made it more possible for carmakers to cheat the tests and make it hard to detect.

One of the most famous examples is Volkswagen. In 2015, a group of independent specialists found out that the automaker had coded its software to cheat on emissions tests. The software was written to detect when an emissions test was taking place, then change how the engine ran to produce emissions below the required level. Once the test was over, the performance would go back to normal, producing substantially more emissions than during the test.

Despite a few missteps, the truth is that computer controlled emissions systems have gone a long way towards reducing harmful emissions. And the more advanced the systems and computers, the more they’ll be able to decrease the impact of cars on the environment.

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