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This article was published September 22, 2015 at 6:36.
There is software in the middle of dieselgate Volkswagen. A program installed and “turn” in the control unit for the engine management, the well-known 4-cylinder 2-liter turbodiesel TDI allowed to change a number of operating parameters to make the values of emissions in line with the limits set by American for environmental protection, 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 ” (avoidance device) remained silent and off during normal engine operation but was performed only when the criteria for 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) of the car. 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 control unit of the engine switches its operation mode by performing a “mapping” (called Dyno Calibration ) other than the standard ( Road Calibration ) and appropriate for reducing emissions, also acting on systems selective catalytic reduction and on the 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 delivered power curve, the 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 changing the software in whole or replacing the unit or its memory is possible (and many motorists do illegally) develop their car by changing its character. The software is therefore at the heart of modern cars a bit ‘as it is the operating system of a smartphone.
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