Of course, the controller today can instantly calculate the optimal "dose" necessary for the motor at the moment, but for this calculation to be correct, the fullest possible information is needed. Owners of injection cars know: sensors monitor the temperature of the surrounding air, coolant, detonation and oxygen content in the exhaust … Only the temperature of the exhaust has not yet been measured. And it is very important for the proper operation of the converter and its durability. Moreover, modern storage converters require from time to time to burn accumulated substances. How can I do without temperature control?
A conventional semiconductor sensor is not good: it will burn. But the thermocouple is just what you need. When one of its ends is heated, as is known, a difference in electric potentials arises - the greater the greater the difference in temperature. That is, strictly speaking, such a sensor does not measure the temperature itself, but its difference at its ends.
The ABB Automation Products company from the German city of Alzenau proposed a combined thermal sensor for exhaust gases that automatically takes into account the ambient temperature and produces an absolute value with an accuracy of ± 5 ° C. Against the background of 1000 ° C in the exhaust tract, the sensor is quite accurate. And the measurement range is huge: from –40 to + 1110 ° С! Another important advantage of the device is perfect linearity; the output signal is strictly proportional to temperature.
First of all, the device is useful in turbocharged engines, where in no case should the turbine blades be heated above 1000 ° C.
Until now, in order to save an expensive unit, it was necessary to trick: when the driver sharply adds gas, for example, when overtaking, the controller usually not only increases the amount of fuel, but also enriches the mixture, lowering the temperature of the gases. With a temperature sensor, enrichment does not begin immediately, but only when the temperature rises to critical values. In this mode, the exhaust will be cleaner and fuel consumption less.
In the new all-in-one sensor, a thermocouple and measuring electronics: