US 12,253,041 B1
Engine parasitic loading strategy using fuel pressurization
Andrew O. Marrack, Peoria, IL (US); Lifeng Wang, Dunlap, IL (US); and Satya Naga Deepak Pillarisetti, Normal, IL (US)
Assigned to Caterpillar Inc., Peoria, IL (US)
Filed by Caterpillar Inc., Peoria, IL (US)
Filed on Dec. 11, 2023, as Appl. No. 18/535,083.
Int. Cl. F02D 41/30 (2006.01)
CPC F02D 41/3005 (2013.01) [F02D 41/30 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of operating an engine system comprising:
cold starting an engine;
moving a plurality of plungers in a plurality of plunger cavities between advanced positions and retracted positions;
closing a plurality of spill valves each positioned fluidly between one of the plurality of plunger cavities and a low-pressure space to pressurize a fuel in each of the plurality of plunger cavities;
opening a first injection valve in a first fuel injector to inject fuel pressurized by a first one of the plurality of plungers into a firing cylinder of the engine in an engine cycle;
opening one of the plurality of spill valves in a second fuel injector while a second injection valve in the second fuel injector remains closed so as to bleed fuel pressurized by a second one of the plurality of plungers to the low-pressure space in the engine cycle;
parasitically loading the engine via the pressurization of fuel by the second one of the plurality of plungers; and
reclosing and then reopening the one of the plurality of spill valves while the second injection valve remains closed, so as to bleed the fuel pressurized by the second one of the plurality of plungers in a plurality of pulses, and the plurality of pulses are varied with respect to at least one of pulse duration or pulse-pulse dwell time.