Vw Dieselgate, here’s how it worked the trick software – Il Sole 24 Ore

To make its cars equipped with the famous 4-cylinder 2-liter turbodiesel TDI respect legal limits on US emissions, Volkswagen has used a trick software: a Dieselgate made from bits and silicio.Un program installed and did “turn” in the control unit for the engine management, allowing you to change a number of operating parameters to make the values ​​of emissions in line with the limits imposed by the US to protect the environment, the powerful EPA. The trick seems to be been able to reduce emissions of the pollutants in the exhaust 10 to 40 times depending on the conditions of use.

In practice this illegal software application, called “defeat device” means a device for circumvention , remained silent and off during normal engine operation but was performed only when the criteria and approval. As? Through the occurrence of a number of conditions, such as steering angle, the speed of the vehicle (if the test is conducted on roll dynamometers must be zero), the number of revolutions of the engine and, probably, l ‘ inclusion of digital probe for analysis in the diagnostic port (OBD). If all of the preconditions laid down by the person who completed (and installed) that program and documentation of accusation EPA is called “The Switch, the switch”, then the engine control unit switches its operation mode by running a “mapping” (named Dyno Calibration) other than the standard (Road Calibration) and appropriate for reducing emissions, also acting on selective catalytic reduction systems and trap for oxides of nitrogen.

The mappings are in fact the sets of data and information critical to the operation of the engine which also come from sensors such as, for example, those of position of the crankshaft or of the camshaft of the distribution. For each mapping match different performance in terms of power output, maximum torque at a given number of revolutions and of course different levels of pollutant emissions (SOX, sulfur oxide and nitrogen oxide NOX) and carbon dioxide. By modifying the software (stored memory EPROM (Erasable Programmable Read-Only Memory) or replacing the whole unit or its memory it is possible (and many motorists do illegally) develop their car by changing its character. Many cars of the latest generation offer instead the driving mode: by pressing a button on the dashboard switches from normal to sport to echo. The software is therefore at the heart of modern cars a bit ‘as it is the operating system of a smartphone.

Here, makeup in the form of software and silicon engineered by Volkswagen, works the same way but in reverse: altered the parameters and operation of the TDI German to the point of making it much cleaner than it was in reality. At this point of the scandal Volkswagen not only fuel further doubts and concerns about the testing of pollutant emissions (and consumption relative). The tests are in fact based on simulations, such as the EU combined cycle, which prove totally unrealistic, as observed in daily practice and testing the most serious magazines. Cars consume more fuel and emit more pollutants or greenhouse gases than stated simply because the test environment is not representative of the actual reality on the roads. And maybe we need new test more realistic. And at this point the question that arises is one: how many cars are even designed specifically to meet the limits in normal use but then behave very differently consuming more and emitting more pollutants? Many industry insiders speculate that the car scandal Vw is not limited to the United States and perhaps even the only group of Wolfsburg.