SSB Lecturette series: A Scandal with the Diesel Engine - Part 1

The world is going mad over environment protection. Most of the countries have declared their plans to cut out pollution and increase their use of renewable sources of energy by 2030. Even at the UN all countries are going to address environment as their prime concern and discuss ways to decrease pollution overall. And then comes a big scandal from a reputed brand in the world of cars which has shocked the world. Two of the biggest brands of the world, Volkswagen and Audi have been found to be fooling the tests for amount of pollution they have been producing through their cars.

The cars which included versions of Passat, Jetta, Golf, Beetle, and Audi's A3. These vehicles are increasingly popular in the United States, even if they still represent less than 1 percent of the market. Since 2009, Volkswagen has sold more than 4,82,000 clean diesel cars containing a four-cylinder turbocharged direct injection engine.

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Why Diesel cars are so famous in USA and Europe?

Cars have two types of combustion engine: Diesel and Gasoline. Diesel engines have been popular in Europe because of their major advantage of fuel economy. Diesel contains more energy per gallon than gasoline, and the diesel engines work more efficiently. The typical diesel car travel up to 30 percent farther on a gallon of fuel than its gasoline engine.

But there is a problem with a diesel car i.e. when they get better mileage they emit fewer carbon-dioxide emissions; they also emit more nitrogen oxides (NOx) , which help in forming smog and particulate matter which can damage lungs. Both types of pollution can have serious health effects.

Europe on one hand had been imposing lenient laws for diesel engines in pursuit of better fuel economy. Roughly one-third of the cars in Europe run by diesel which has had a serious smog problem in cities like Paris. While on the other hand US has imposed far stricter rules around smog and other pollutants since the 1970s which is why diesel cars do not have a strong market in USA since only a few cars could pass America's stringent NOx standards.

But since 2009, things started to change when Obama administration started to give importance to fuel economy standards in the United states Moreover  they considered the fact that diesel technology have been gradually getting cleaner through a combination of lower-sulphur fuel, advanced engines, and a new emission-control technology.  Hence, automakers have started making cars which give better performance whilst having pollution under control.

The Scandal:

Now-a-days the cars have become sophisticated in terms of technology. There are many computers in a car which help in improving the performance of the car. These computers make the adjustments in fuel and air which enters the engine. The diesel cars though have one more important feature regarding the un-burnt fuel which goes into the exhaust pipe. Also, these cars have NOx traps which do not allow nitrogen oxide to go out of the car's exhaust. Moreover, the effectiveness of these NOx traps is enhanced by these un-burnt fuels.

Volkswagen had cars which were famous for having great fuel economy along with less pollution. But the trick of having less pollution was to have un-burnt fuel to be released in the NOx trap, which would ultimately lead to less efficiency. Hence, what did Volkswagen do to cover these problems?

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What Volkswagen did was to use a Defeat device which was software program which turned on when there was an emissions test being done. Hence, while the test was being done it would allow more un-burnt fuel into the NOx trap hence less pollution. But when it would get on the road the defeat device would turn off and hence, it would produce more pollution in the environment. The pollution was up to 40 times the standard suggested by EPA (Environmental Protection Agency).

But how did the device know that the car was being tested? According to the EPA, the device would check factors like Steering wheel position, pedal movements, speed of the car, atmospheric pressure and how long the engine was on. Hence, make the necessary adjustment to make this deception possible.

Keep waiting there is lot more in this story... How this scandal was caught and what happened with the companies will be revealed in the next part. Keep reading.
SSB Lecturette series: A Scandal with the Diesel Engine - Part 2

About the Author:  Pranav Nikam is an Electrical and Electronics engineer who is working in a renowned MNC in Chennai. He likes to work out in gym, do photography and play badminton. Through his articles he wants to spread awareness among other defence aspirants.