Parameters / Conditions For Closed Loop Operation on SULEV

.22.00.00 Parameters / Conditions For Closed Loop Operation On Sulev

General
The SULEV concept consists of 2 catalysts and 3 control loops. The first control loop uses the Oxygen sensor pre catalyst (LSU) in the same manner conventional concepts does. The Oxygen sensor between the two bricks (LSF1) of the catalyst is the input for the second and the Oxygen sensor after the last brick (LSF2) is the input for the third control loop. Both sensors are binary Oxygen sensors. The closed loop operation of each of the control loops are in a depending order of 1st, 2nd and 3rd control loop.
In comparison to post catalyst control loop on conventional concepts the 2nd and 3rd control loop are high precision loops with specific requirements for short-term correction and long-term adaptation. The driving conditions have to be stable and constant to allow any corrections by these control loops. The allowed correction steps are much smaller in comparison to post catalyst control loop applications on conventional concepts.

Conditions for closed loop operation of the first control loop
The conditions for closed loop operation of the first control loop on the SULEV concept are the same as described for conventional concepts.

Conditions for closed loop operation of the second control loop
The second control loop on the SULEV concept is designed as natural frequency control loop and is based on a binary Oxygen sensor. The controller has the same capability in achieving maximum conversion on the first brick of the catalyst by using a proportional adjustment range for short term correction and an integral adjustment range for long-term adaptation (PI-controller). Both controller ranges have individual conditions for closed loop operation.


Enable criteria for P-portion of the controller of second control loop (SULEV)
The proportional-portion of the controller corrects short-term deviations.







Enable criteria for adaptive I-portion of the controller second control loop (additionally)
The integral-portion of the controller corrects permanent deviations / shifts over a longer time by adjusting the adaptation.







Typical Values (second control loop)
Given a normal cold started FTP (around 20 degrees C) most of the concepts reaches the closed loop condition for the second control loop within 60 s to 80 s.

Conditions for closed loop operation of the third control loop
The third control loop is designed like the second control loop on conventional concepts and achieves the maximum conversion of the 2nd brick of the catalyst. The controller consists of very restricted correction ranges for the short-term proportional and the long-term integral adaptive portion (PI-controller). Both controller ranges have individual conditions for closed loop operation.

Enable criteria for P-portion of the controller of third control loop (SULEV)
The proportional-portion of the controller corrects short-term deviations.







Enable criteria for adaptive I-portion of the controller third control loop (additionally)
The integral-portion of the controller corrects permanent deviations / shifts over a longer time by adjusting the adaptation.







Typical Values (third control loop)
Given a normal cold started FTP (around 20 degrees C) most of the concepts reaches the closed loop condition for the third control loop within 90 s to 100 s.