In Gen 5 DD13/DD15 engines, what design is used for the EGR cooler/coolant collector?

The design used for the EGR cooler/coolant collector in Gen 5 DD13/DD15 engines is indeed a removable EGR cooler with a 3-piece coolant collector system. This design offers several advantages, primarily related to maintenance and efficiency.

The 3-piece coolant collector allows for easier replacement and serviceability of the EGR cooler. If issues arise with the cooler, rather than needing to replace a complex assembly or the entire system, technicians can replace just the cooler section which simplifies the process and reduces downtime. This modularity is particularly advantageous in heavy-duty applications where engine uptime is crucial.

Furthermore, the removable design helps to manage heat more effectively, which is critical for the EGR system's performance and longevity. Proper heat management contributes to the system's overall efficiency in reducing nitrogen oxides (NOx), which is essential for meeting emissions standards.

In contrast, other designs mentioned, such as a one-piece collector or an integrated cooler attached directly to the head, may offer permanence but can complicate maintenance procedures and increase the time and cost associated with repairs. The flexibility provided by the removable setup aligns well with industry trends towards more service-friendly engine designs.