Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p73
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 73/150)
Character Range: 916189–919604

the LNT system on engines so-equipped for proper operation:
           (a) LNT capability: the LNT system's ability to adsorb/store and convert NOx - performance monitoring;
           (b) LNT active/intrusive reagent injection system: the system's ability to regulate reagent delivery properly, whether delivered via an in-exhaust injection or an in-cylinder injection - performance monitoring.
       Appendix 3 - Item 5
       Oxidation catalysts (incl. Diesel Oxidation Catalyst – DOC) monitoring
       This item applies to oxidation catalysts that are separate from other after treatment systems. Those that are included in the canning of an after treatment system are covered within the appropriate item of this appendix.
       The OBD system shall monitor the following elements of the oxidation catalysts on engines so-equipped for proper operation:
           (a) HC conversion efficiency: the oxidation catalysts ability to convert HC upstream of other after treatment devices - total functional failure monitoring;
           (b) HC conversion efficiency: the oxidation catalysts ability to convert HC downstream of other after treatment devices - total functional failure monitoring.
       Appendix 3 - Item 6
       Exhaust Gas Recirculation (EGR) system monitoring
       The OBD system shall monitor the following elements of the EGR system on engines so-equipped for proper operation:
                                                                                                                                                                                                                   Diesel      Gas
(a1) EGR low/high flow: the EGR system's ability to maintain the commanded EGR flow rate, detecting both "flow rate too low" and "flow rate too high" conditions – emission threshold monitoring.              X
(a2) EGR low/high flow: the EGR system's ability to maintain the commanded EGR flow rate, detecting both "flow rate too low" and "flow rate too high" conditions - performance monitoring.                                 X
(a3) EGR low flow: the EGR system's ability to maintain the commanded EGR flow rate, detecting "flow rate too low" conditions – total functional failure or performance monitoring as specified in this item.  X           X
(b) Slow response of the EGR actuator: the EGR system's ability to achieve the commanded flow rate within a manufacturer specified time interval following the command – performance monitoring.               X           X
(c1) EGR cooler under cooling performance: the EGR cooler system's ability to achieve the manufacturer's specified cooling performance – performance monitoring.                                               X           X
(c2) EGR cooler under cooling performance: the EGR cooler system's ability to achieve the manufacturer's specified cooling performance – total functional failure monitoring as specified in this item.        X           X

          (a3) EGR low flow (total functional failure or performance monitoring)

       In the case where the emissions would not exceed the OBD threshold limits even upon total failure of the EGR system's ability to maintain the commanded EGR flow rate (for example, because of the correct functioning of an SCR system downstream of the engine), then:
           1. Where the control of the EGR flow rate is performed by means of a closed-loop system, the OBD system