Issue link: https://te.mouser.com/i/1349215
Sensors for the Connected Car TE AUTOMOTIVE /// White Paper Seite 7 diesel emission fluid, or DEF) is injected into the exhaust gas flow of a diesel engine. In the exhaust flow the urea converts into ammonia which then reacts with the NOx content and breaks it down into harmless nitrogen and water. To ensure an optimal conversion rate of the nitrogen oxides in the exhaust gas, the amount of injected urea needs to be constantly adjusted to the NOx content in the exhaust gas flow which varies with the engine load and operation. If this control is not precise enough, two things can happen: - If too much urea is injected, ammonia will be emitted from the tailpipe. - If too little urea is injected, NOx will slip through the SCR system. One parameter of this control function is to factor in the actual urea pressure in the pipe leading to the urea injector. TE's urea pressure sensor technology is already proven for this purpose in trucks. The new automotive urea pressure sensor makes this function available to cars. Based on a piezoresistive measuring principle, the urea pressure sensor features a custom ASIC (i.e. an Application-Specific Integrated Circuit), which processes diaphragm reflection to measure absolute fluid pressures of up to 13 bar or sealed gage pressure. The sensor's stainless steel wetted surfaces are fully compatible with the aggressive chemistry of the fluid. Despite its small size the sensor has a data storage possibility. Overall it measures pressure with an accuracy in the range of 2%. Interface options are analog or the digital SENT protocol. Thanks to a silicone oil chamber, transferring the medium pressure to the steel diaphragm, the TE urea pressure sensor has been successfully tested up to 1000 freezing cycles. It is freeze-proof, which addresses a concern of vehicle manufacturers as the urea solution freezes easily and can damage some pressure sensor designs. The new automotive urea pressure sensor broadens the TE SCR sensor portfolio which also includes a high-performance urea quality sensor that is also a urea concentration sensor (DEF sensor), which is used as an integral part of NOx emission control and compliance strategy. B | Transmission oil pressure sensor Efficiency and comfort of auto- matic transmissions strongly depend on hydraulic actuation, controlled by hydraulic valves. Applications include standard automated transmission (AT), continuously variable transmis- sion (CVT) and dual clutch trans- mission (DCT). A sensor serves to monitor the correct transmission oil pressure at all times to ensure correct valve action. Transmission sensors have to function reliably in one of the most severe automotive environ- ments. In a "wet" application (i.e. fully integrated within a trans- mission) the sensor is exposed to aggressive hot transmission oil and metal particles stemming from mechanical abrasion. TE's new rugged transmission oil pressure sensor is designed for full integration and functions reliably in this environment. At only 18 grams of mass the new sensor measures up to 100 bar, withstands pressure