Now in its sixth generation, DDEC (Detroit Diesel Electronic Control or “dee-deck”) was the first EMS designed for heavy-duty diesels. Later versions follow European practice by incorporating VGT, large amounts of EGR, and exhaust aftertreatment.
VGT generates boost across the whole rpm band. It also enables large amounts of exhaust gas to be recirculated under load, when EGR is needed most. Exhaust aftertreatment traps particulates and converts oxides of nitrogen, which are smog precursors, into nitrogen and water.
The complexity of later DDEC systems and a design philosophy that ties the product closely to service facilities severely limits what can be done without access to factory documentation and a DDR/DDL (Diagnostic Data Reader/Diagnostic Data Link). What follows pretty well sums up what a nonfactory technician, armed with a volt-ohmmeter and a generic J 1587 data-link scanner can accomplish. Table 6-5 lists Detroit Diesel nomenclature.
Figure 6-23 illustrates Series 60 DDEC V component locations and Figs. 6-24A and B illustrate schematics for injector and VPOD wiring. In addition to those called out in the schematics, DDEC V and VI systems incorporate sensors that monitor:
• Ambient air temperature and pressure
• EGR Delta-P and flow rate
• Turbo boost and rpm
• VGT vane position