The grid heater in the Cummins have nothing to do with the emissions qualification if, in fact, the heater controller is programmed to come on only below 60 degreased.
The emissions test qualification cycle doesn’t run below room temperature.
The heater is strictly for sociability reasons. Cummins wants the engines to start and clean up quickly to get rid of the old stinky Diesel reputation compression ignition engines deservedly developed from pre emissions days, when they were primarily industrial power plants.
Pretty much all modern diesels have glow plugs or grid heaters. Cummins was actually the last manufacturer to come to the party. Their last P pump engines in the 90s were notoriously poor cold performers, and would envelop the truck with white smoke after startup at low temperatures. It’s not 1964 anymore.
The common rail engines have incredible flexibility to develop cold start strategies and calibration compare to the primitive mechanical fuel systems of years past.
Pilot injection allows very low injection rates, which minimizes heat loss in the combustion chamberas the fuel vaporizes, and the unlimited timing flexibility can optimize start of combustion for low temperature ignition delays to minimize white smoke formation.
