BROADVIEW, Ill. – This week, our Executive Interview series features Warren Suter, director of engine management systems for Robert Bosch LLC. In the interview, Suter talks about Bosch’s role in the development of new O2 sensor technologies, as well as trends in the product category, and also discusses the education and marketing programs Bosch produces to help inform consumers about O2 sensors. Read on to learn more.
What has Bosch’s role been in the development and advancement of the O2 sensor?
The technology behind the automotive oxygen sensor dates to 1920 when Walther Nernst received a Nobel Prize in chemistry for his equation relating to the solid state zirconia oxygen sensor. But it was Bosch engineers who worked for decades and developed the first viable automotive oxygen sensor, used in a 1976 Volvo. This first-generation O2 sensor enabled compliance with Clean Air Act mandates for monitoring and reducing the HC, CO and NOx levels in automotive exhaust.
Soon after the initial success of this early technology, Bosch engineers developed the heated O2 sensor, which responded much more quickly in cold engines when the rich mixtures needed for start-up and cold weather operation created the highest levels of pollutants. Heated O2 technology also permitted placement of the sensor further downstream since it didn’t require exhaust heat to bring it to proper operating temperature. This placement further downstream moved the sensor further from the heat and corrosive chemicals normally found in the exhaust stream, thus extending sensor life significantly.
New-generation “wideband” sensors, also developed by Bosch, provide continuous data output rather than the more simple “on/off” output of earlier sensors, while reaching operating temperature almost instantly. The result is more precise control of the fuel/air mixture and combustion than was ever before possible. Bosch developed the very first automotive oxygen sensor, is responsible for every significant innovation in O2 sensor technology, and makes more O2 sensors for more types of vehicles than any other manufacturer.
What are some of the features of the Bosch O2 sensor program?
Bosch’s aftermarket oxygen sensor program combines all available technologies to provide the right sensor for any vehicle: Asian, Domestic, or European car or light truck. Our wire harnesses are designed for fast installation and OE fit. All of our oxygen sensors are made to OE specifications in plants certified to OE quality standards.
What is Bosch doing to educate the public about the role and importance of replacing their vehicle’s oxygen sensor?
On our Web site, http://www.boschautoparts.com, we provide consumers with information about their vehicle’s emission system and the role of oxygen sensors. We provide tips on routine maintenance and a search function to find the correct part for their vehicle. We even provide a map to the nearest Bosch Oxygen Sensor dealer. We support a variety of schools and training opportunities for service technicians to quickly and correctly diagnose Engine Management and Oxygen Sensor System problems. We regularly answer questions on radio talk shows and in automotive publications.
Can an O2 sensor be faulty even when the “check engine” light is not on?
Over time, exhaust contaminants build up on the sensing element of oxygen sensors. These deposits reduce the response time of the sensor and eventually impact the emission system effectiveness. Even before the check engine light comes on, the system may begin to deteriorate. Rough idle, sluggish performance and increased fuel consumption are all signs of a "lazy" sensor.
With the universal line of O2 sensors, how many part numbers are needed to cover the majority of the vehicles on the road?
We offer a program of universal-type sensors for customers who need the correct sensor, but don’t have access to a large selection. The OE SmartLink connectors allow only 14 sensors to replace nearly 90 percent of all sensors on the road. The technician or "do-it-yourselfer" re-uses the OEM wire harness and makes a professional, waterproof connection to a brand new sensor. This concept offers fast replacement and much lower inventories for service and maintenance professionals in areas where access to distributors is limited.
As vehicle engines become “greener,” what does Bosch see as the future of O2 sensor technology and its role in the emission system?
Alternative fuels are one way that vehicle manufacturers are helping the driving public contribute to a cleaner environment. Whether for gasoline, diesel, ethanol, compressed natural gas, bio-diesel or even Flex-Fuel engines, Bosch sensors provide the vehicle control systems the information needed to maximize fuel economy and reduce pollution. In this world of trade-offs, I don’t know of many products that have had such a significant impact on the environment. Even hybrid vehicles use small internal combustion engines to charge batteries and provide extended driving range. These, too, rely on oxygen sensors for engine control.
Can you talk about the next generation of Air/Fuel sensors (advanced O2 sensors) that are now being used on a growing number of late model cars? How do they differ from ordinary O2 sensors? Do they last longer? Do they require any special service or replacement procedures?
For the independent aftermarket, Bosch has adopted the name “Wideband A/F Sensor” to refer to oxygen sensors that provide a variable output depending on the oxygen content in the exhaust gas. These sensors are also referred to as “Air-Fuel Ratio Sensors” or “Broadband Sensors.”
Earlier switching and wideband designs, have several limitations. Among those limitations, both types rely on a volume of reference air used to compare the exhaust gases to provide a reading. Should this reference air become contaminated, the readings would be inaccurate. Owing to its unique design, the planar sensor element allows a variation on the Nernst cell that adds a pumping function. This function can continuously pump oxygen into the reference chamber. This "pumped reference" completely eliminates the problem of contamination and increases the sensitivity of the sensor. Smaller, faster sensors based on this design are already finding their way into new vehicles.
Most European and Asian vehicles are now equipped with wideband A/F sensors, and Domestic manufacturers are moving to adopt them. Due to their ability to provide readings in the lean part of the Air/Fuel spectrum, wideband A/F sensors are increasingly found on diesel applications. Wideband A/F sensors are only found in the pre-catalyst position on gasoline engines. Traditional switching-type sensors cannot be interchanged with a wideband A/F sensor. In other words, it’s not possible to “upgrade” from a switching-type sensor to a wideband A/F sensor without changing the entire engine management system.
