Lambda sensors

Bosch Oxygen Sensor Design Types | A 7LSU “Broadband” Universal Sensor - as its name suggests,the broadband oxygen sensor has the ability to not onlyindicate an air/fuel ratio of lambda = 1 but can measureas low as lambda = 0.7 up to infinity (infinity =atmosphere containing oxygen of ~ 21% by volume). Thisis a unique quality compared to the “two step” rich/leanfunction of a standard thimble or planar sensor.This LSU type sensor has not only been successfully appliedto standard petrol engined passenger cars, but for leanburnand gaseous fuelled engines. Due to their uniquedesign these sensors are also used in diesel poweredvehicles equipped with electronic diesel control (EDC)systems and industrial applications including gas poweredfurnaces, air/fuel ratio measuring equipment andengine/chassis dynamometers.Broadband oxygen sensors can only be used inconjunction with a control unit that is specially designedto support the operational function and precise heaterelement management required by an LSU broadband sensor.It is important to note that a specifically designed wiringharness connector containing 6 pins is used for LSU typesensors. Whilst the physical appearance of the oxygensensor connector will vary according to customer andvehicle design requirements, all LSU sensors have acalibration resistor built into the connector housing. Eachindividual LSU sensor is calibrated at the conclusion ofthe manufacturing process by laser altering this resistorvalue. Therefore removal or exchange of the oxygen sensorconnector will render the sensor inoperable.Cross Section of LSU Broadband Sensor1 = Nernst cell2 = Reference cell3 = Heater4 = Diffusion gap5 = Pump cell6 = Exhaust pipeComprehensive technical descriptions of construction andoperation of these sensor types as well as many new Boschsensor developments can be found in the Bosch TechnicalInstruction Manual titled “Automotive Sensors” (part # 1 987722 131) available directly from Bosch Australia’s technicalliterature department on 03 9532 1081.Planar Sensor Operational Layers1 = Porous protective layer2 = External electode3 = Sensor laminate4 = Internal electrode5 = Reference air laminate6 = Insulation layer7 = Heater8 = Heater laminate9 = Connection contacts2009 | 2010 Bosch Automotive Aftermarket