My turn for a stupid question...

[Will24]

Just curious...



Is the Cummins HPCR injection sort of like an all electronic version of the Cummins PT system? I figure both are common rail, but there is an ECM in place of the Cam (essentially a mechanical computer) and sensors in place of the various mechanical inputs of the PT system. Is my thinking completely off base?





-Will

 

[Joseph Donnelly]

Kinda.

Remember that pressure on the HPCR does not vary with rpm like the pt, the electronics allow pilot injection and much more precise control of the fueling event. The electronics control fuel delivery quantity and timing, idle and governed sped, and torque (fueling) curve. The PT can give 20,000 psi but the common rail is at low pressure, more like a basic feed system. The PT has a mechanical flyball governor. It was introduced in 1951.



See TDR #42 p. 26 for some info on the HPCR. "Diesel Engine and Fuel System Repair" by John F. Dagel and Robert N. Brady, Prentice Hall, 1998 gives info on the PT.

 

[Will24]

Good deal, thanks for the info. Actually, tomorrow I'll have that book since it's required for my fuels lab next semester



-Will