Oxygen Sensors
LSU Broadband Oxygen Sensors- Installed upstream of the pre-catalytic converters in USA vehicles only
- With DME control unit ME 7.8_40_LSU
To ensure compliance with US emission regulations, the LSU broadband oxygen sensors are installed ahead of the pre-catalytic converters on each cylinder bank on the Boxster S. In contrast to the step oxygen sensor, which merely indicates whether the engine mixture is lean or rich, the continuously measuring broadband oxygen sensor assesses precisely how lean or rich the mixture is.
This additional information enables the mixture to be adjusted to ensure that the catalytic converter operates effectively. This is also possible when highly dynamic load changes apply. Vehicles equipped with this broadband oxygen sensor run with oxygen sensor control shortly after cold starting, from idling up to full throttle. The LSU broadband oxygen sensor represents a further development of the LSF oxygen sensor.
Advantages of the LSU broadband oxygen sensor:
- Exact measurements from Lambda > 0.7 (rich mixture) to Lambda < 4 (pure air) are possible.
- The LSU sensor supplies a continuous signal, which is evaluated in the Motronic control unit.
- Controlled operation with oxygen sensor control is possible in all conditions.
- The broadband oxygen sensor probe is ready for use very quickly.
- The oxygen sensor control circuit responds faster to a change in the mixture.
- Improved regulating action with increased dynamism.
Design of the LSU broadband oxygen sensor:
- The LSU consists of different planar functional layers
- The actual sensor element of the broadband oxygen sensor consists of a combination of a Nernst concentration cell (1) and a pump cell (2) transporting oxygen ions.
- The broadband oxygen sensor requires a special operating electronics system (6) in the form of an evaluation circuit in the Motronic control unit.
- The evaluation circuit contains the control electronics for the pump cell and the sensor cell to generate the sensor signal.
- The control current of the electronic pump cell always generates Lambda 1 in the measuring cell (3).
- Lambda 1 is monitored continuously via the voltage of the sensor cell.
- The evaluation circuit calculates the precise Lambda value of the exhaust gas on the basis of the deviation of the pump cell current (0 mA ± 1 mA).
- LSU temperature control is also integrated in the evaluation circuit.
LSF Oxygen Sensor
- Installed downstream of the pre-catalytic converters in all vehicles worldwide.
The LSF oxygen sensor represents a further development of the heated oxygen sensor. Its functions correspond to those of the heated LSH oxygen sensor with a transient response of 0 to 0.9 volts at Lambda 1. In contrast to the old LSH step oxygen sensor, ceramic films form the solid electrolyte for the LSF oxygen sensor.
- 4wires from the DME control unit
- 4wires to the LSF oxygen sensor
- Slimline connector housing (without resistor)
Special characteristics of the LSF oxygen sensor:
- Fast operational readiness
- Low heating power requirement
- Stable control characteristics
- Small, light
The sensor element of this planar oxygen sensor consists of ceramic films and has the form of a long plate with an rectangular cross-section. The respective functional layers (electrodes, protective layers, etc.) are produced by means of a screen printing process. The manner in which the different printed films are laminated one onto the other means that it is also possible to integrate a heating element in the sensor element.