Bosch Oxygen Sensors

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Bosch Oxygen Sensors Review

Pioneered by Robert Bosch in the 1960s, Bosch Oxygen Sensors have led the auto market ever since.

What is an Oxygen Sensor?

Let’s start with the basics and a brief introduction to what is an Oxygen Sensor? An Oxygen Sensor is an electronic device that records the amount of oxygen (O2) in what is being measured, typically liquid or gas.

Oxygen Sensors are also known as Lambda Sensors but this is a common slight misunderstanding in that a Lambda Sensor is actually a type of Oxygen Sensor in the same way as a Hoover is a type of Vacuum Cleaner.

Standard output voltages on most Oxygen Sensors doesn’t vary much with oxygen concentration but is impacted significantly when the oxygen concentration in the car exhaust system falls very low due to a richer mixture. However, the output voltage of Lambda Sensors are more even as oxygen concentration levels change, making the Lambda Sensor more sensitive to air-fuel mixtures and providing greater accuracy in readings.

Oxygen sensors are known under other names too, wideband oxygen sensors and air-fuel sensors. Bosch themselves use three types of oxygen sensor;

  • Bosch Premium Oxygen Sensors – thimble and planar switching sensors that are designed to meet or exceed OE specifications.
  • Bosch Premium Wideband A/F Oxygen Sensors – more sophisticated sensing elements that provide a signal to the vehicle’s ECU that is proportional to the amount of oxygen in the exhaust.
  • Bosch Universal Oxygen Sensors – with OE SmartLink and are quick and easy to install.

Early Bosch sensors were made with a thimble-shaped zirconia ceramic coating on both sides. It was over 20 years later before the planar-style sensors were introduced, improving the sensors’ capability by starting quicker and responding faster due to reduced ceramic coating and incorporating the heater within the ceramic structure.

What are Oxygen Sensors used for?

Typical use of Oxygen Sensors, and Lambda Sensors, is to measure the auto exhaust fumes oxygen concentration levels in cars, motorbikes etc and where necessary to adjust the air-fuel ratio so that catalytic converters work at their optimum level, which in turn shows whether the converter is working correctly or not.

Oxygen sensors are also used in hypoxic air fire prevention systems to continuously monitor the oxygen concentration inside the protected volumes.

Why are Oxygen Sensors important?

Too much oxygen in an exhaust system or insufficient fuel being fed to the engine indicates a lean mixture, which can cause vehicle performance issues. On the other hand, too little oxygen or excess fuel in the exhaust system usually indicates a rich mixture, which results in the vehicle performing at lower MPG levels and also excessive emission levels, none of which is good for the vehicle, driver or environment.

Failure of the Oxygen Sensor or exhaust system fuel mixture can cause the catalytic converter to fail and thus need replacing, which can be expensive. All motor vehicles
produced since 1996 will have at least two converters, one sensor is located before the catalytic converter which communicates with the Engine Control Module (ECM) to let the car know if it needs to use more or less fuel. A second sensor is located after the catalytic converter to make sure that the catalytic converter is working properly.

What is the difference between Wideband Sensors and Air-Fuel Sensors?

Bosch Air-Fuel Oxygen Sensors detect if a vehicle is running rich or lean whereas Bosch Wideband Oxygen Sensors measure the exact amount of oxygen in the vehicle exhaust system in order to communicate this to the ECU and therefore to manage the amount of required fuel for optimum performance. Bosch Wideband Oxygen Sensors are advanced sensors which have enabled auto manufacturers to increase fuel economy and improve engine performance.

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