June 29th 2007
The first oxygen sensors relied on heat from the exhaust to reach operating temperature, and are now known as "unheated thimble" oxygen sensors. The term "thimble" refers to the hollow ceramic thimble that extends into the exhaust stream.
Because the warm-up cycle of an engine produces the most exhaust emissions, in 1982 Bosch developed the “heated thimble oxygen sensor,” which uses an electrical heating element inside the thimble to bring the sensor up to operating temperature in less than a minute. Since then, the heated thimble sensor has become the standard for most automobiles and light trucks around the world.
More stringent exhaust emission requirements in the mid-1990s led to the development of “planar sensors,” which deliver a reading within 10-12 seconds after an engine is started, and feature a flat, ceramic-zirconia element projecting into the exhaust stream. The planar sensors have won widespread acceptance, and already account for almost 50 percent of oxygen sensors installed in new vehicles in the United States.
Further advancements have led to the development of the “heated wide-band oxygen sensor,” which is similar to the planar sensor, but provides a variable signal all the way from very lean to very rich to the engine’s computer, allowing even greater refinements in the air/fuel mixture -- and more efficient vehicles.
As sensor design and manufacturing technology advances, replacement sensors will often reflect those advancements, and may well outperform and outlast the original. Advancing sensor technology will continue to bring improvements in driving efficiency and driving pleasure.
Diyautoparts.com proudly carries Bosch and other OEM quality oxygen sensors. If you have any questions about oxygen sensors feel free to contact one of our auto parts professionals at 1-800-593-1443.
