2JZ Tuesday - Bosch LSU 4.9 and LSU 4.2 differences
Have you ever wonder what is the difference between Bosch LSU 4.2 and LSU 4.9? And why we always use LSU 4.9 even though it is slightly more expensive? Here comes the 4 differences between these 2 O2 sensor/ wideband sensor/ lambda sensor and why you should use LSU 4.9 wherever is applicable.
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1. The major difference between LSU 4.9 and 4.2 is that LSU 4.9 uses the reference pumping-current, while LSU 4.2 uses the reference air.
Basically the reference air can deteriorate while the reference electric signal does not
when Bosch first designed a wideband oxygen sensor, a reference air cell was used to provide a reference of stoic air-fuel-ratio, or AFR.
It worked well in the lab, but not so good in the real life, because the environment around the sensor on a car was much worse. The reference air cell could be contaminated by the surrounding pollution. Once the reference air was contaminated, the whole characteristics of the sensor were shifted to the lower side.
The LSU 4.9 sensor got rid of the reference air. Instead, it used a reference pumping current. The actual pumping current was still the indication of the actual AFR, but the reference was a calibrated electrical signal, and stayed same all the time, all the situations
LSU 4.9 gets rid of the reference air, and therefore gets rid of the biggest failure mode. As a result, LSU 4.9 has a long life and can maintain the accuracy throughout the life.
2. LSU 4.9 have a good heating control strategy.
The accuracy of LSU sensors is highly dependent on the operating temperature of the sensing element. The sensor reading can be very different if the temperature of the sensing element is different. LSU sensors must work at the vicinity of certain temperatures for the good accuracy. LSU4.9 sensor must be maintained at 780 degrees Celsius precisely
Bosch CJ125 chip is designed for this task. As a result, 4.9 has a longer life and better accuracy
3. LSU 4.9 has Thinner sensing element. Means higher accuracy and sensitivity
4. LSU 4.9 has new design of protection tubes. It has complicated structure that can create gas rotations around the sensing element, and it also blocks the liquid droplets reaching the sensing element. Benefits: improved gas flow, faster dynamic response and significantly reduced thermal shock risk and it has been the number one killer of the oxygen sensor all the time.
Here it comes the hands down easiest way to select Bosch o2 or oxygen sensor, LSU 4.2 or LSU 4.9!
Hope you guys enjoy this video series, and comment below anything from your experience regarding oxygen sensor, good and bad! The community would benefit from your input too =)
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