From which cylinders do EGR gases come in DD13 and DD15 engines?

In DD13 and DD15 engines, the Exhaust Gas Recirculation (EGR) gases come primarily from cylinders 1, 2, and 3. This configuration is designed to optimize the combustion process by recirculating a portion of the exhaust gases back into the intake manifold. The use of EGR helps in reducing nitrogen oxide (NOx) emissions, as it lowers combustion temperatures and minimizes the formation of these harmful pollutants.

The design choice of utilizing gases from cylinders 1, 2, and 3 typically relates to their position within the engine and how the exhaust manifold is configured. This selection ensures that the EGR system is efficient and effective in mixing the recirculated gases with fresh air before it re-enters the combustion chamber. Understanding which cylinders contribute to EGR is crucial for diagnostics and performance tuning, especially when diagnosing issues related to emissions and engine efficiency.