Reductant delivery unit for selective catalytic reduction for vehicles with thermally optimized peak and hold action based on injector opening event

摘要

A trigger circuit is provided for a peak and hold driver circuit for a reductant delivery unit (RDU) having a solenoid-operated injector for selective catalytic reduction (SCR) after-treatment for vehicles. The peak and hold driver circuit is constructed and arranged to actuate the injector in a rise-to-peak current phase followed by a low current hold phase. The trigger circuit includes an injector open detection circuit constructed and arranged, based on a detected opening event of the injector, to trigger a transition from the rise-to-peak phase to the subsequent hold phase of the injector.