Cummins HPI-TP Chapter 29

1. Cummins HPI-TPChapter 29 Dsl 131

2. OBJECTIVES • Identify the engine family using the HPI-TP fuel system. • Outline the changes required by ISX for 2004, 2007, and 2010 EPA emissions. • Describe the HPI-TP fuel subsystem. • Trace fuel flow routing from tank to injector in a typical HPI-TP-fueled engine. • Recognize the components of an IFSM module. • Describe the operation of timing and metering actuators. • Understand the operating principles of the HPI-TP system. • Outline some of the features of an ISX engine.

3. INTRODUCTION • The current Cummins high pressure injection-time pressure (HPI-TP) fuel system was used on the successful ISX series engines until 2010. • In 2010, Cummins re-engineered to the ISX for a standard common rail (CR) fuel system they call XPI.

4. TP HYDRAULIC EQUATION • In describing the TP system, note that the letters TP refer to two of the three factors of a hydraulic equation whose product is a volume of fuel flow. • Recall from earlier chapters that the output of a diesel engine is determined by the volume of fuel metered into its cylinders.

5. TP HYDRAULIC EQUATION (Cont.) • Thus if we construct a hydraulic equation whose product is a volume of flow, it has three factors: • Flow area • Pressure • Time of flow

6. ENGINE MANAGEMENTELECTRONICS • ISX engine management electronics use Cummins common platform ECM architecture known as Interact System or IS. • Engine performance and engine subsystems are precisely monitored and managed, and the engine electronics connect to the J1939 data bus.

7. FUEL SYSTEM COMPONENTS • The Cummins HPI-TP CR system is designed to manage the hydraulic fueling equation by holding the flow area constant, holding the pressure value constant, and using the time factor as the control variable.

8. Heavy Duty HPI-TPFuel System Schematic

9. FUEL SYSTEM COMPONENTS (Cont.) • Integrated Fuel System Module (IFSM) • Check Valve • Fuel Filter/Water Separator • Gear Pump • Lift Pumps • Actuators • Pulsation Dampers • Fuel Shutoff Valve • Fuel Pressure Sensor • Unintended Fueling Sensors

10. FUEL FLOW • The fuel flow routing has changed with successive generations of HPI-TP.

11. Fuel Flow Schematic

12. CAUTION • In post-2004 ISX-TP engines, the filter flow routing changed and became subject to charging pressure: these later filters are smaller in size and more robust in construction.

13. Timing and Metering Actuators

14. HPI-TP Internal Components

15. TECH TIP • Make sure that you understand how fuel is flowed through the HPI-TP fuel system, and it will make the task of priming the fuel system that much easier when using INSITE software guided instructions. • Also be sure that you know the generation of the engine on which you are working: the filter may be under pull (suction) or subject to charging pressure.

16. External View of an HPI-TP Injector

17. Left-Side View of an ISX Engine

18. OVERHEAD ADJUSTMENTS • For truck technicians familiar with setting valves and injectors, the procedure on the HPI-TP versions of ISX is straightforward. • When performing any service work including overhead adjustments, use the Cummins online service literature known as QSOL, and always refer to specifications and check for technical service bulletins.

19. CAUTION • When setting injectors and valves on an ISX engine, both are checked/adjusted on the same cylinder at one timing location. • Always consult Cummins specifications and check for technical service bulletins (TSBs) before attempting the procedure.

20. ISX ELECTRONICS ANDENGINE FEATURES • The electronic input circuit used on the ISX engine is consistent with those on a late-generation, large-bore truck diesel engine. • Sensors requiring reference voltage are fed a 5-DC V-Ref signal, precisely modulated by the ECM.

21. CAUTION • Do not attempt to time ISX overhead camshafts without the Cummins special tool timing wedges. • The consequence of out-of-time camshafts can be a lost engine!

22. Generational Changesin ISX-TP Engines • Early ISX engines used articulating piston assemblies, but Cummins was the first major original equipment manufacturer (OEM) to adopt Monotherm forged steel trunk pistons (see Chapter 7). • Monotherm pistons were introduced for the EPA 2004 model year.

23. ISX Articulating Piston Assembly

24. TROUBLESHOOTING ISX • Troubleshooting problems in all electronically-managed engines should always be performed by technicians with OEM training using guided software and service literature, specifically INSITE and QSOL when working on ISX engines. • Be very sure that the information you are using applies to the specific engine model on which you are working.

25. SUMMARY • The 1998–2010 ISX engines exclusively used the HPI-TP fuel system. • This generation of engines is rated between 385 to 600 BHP with peak torque values slightly exceeding 2,000 lb-ft. of torque. • The HPI-TP fuel subsystem uses a gear pump as the primary means of moving fuel through from the tank to the integrated fuel system module (IFSM). • Depending on the generation of the HPI-TP system, an electric lift pump may also complement the fuel subsystem. • Fuel is pulled through the HPI-TP fueled engine by a gear pump, charged to a common rail, and from there metered by timing and metering actuators to mechanically-actuated injectors. • The IFSM module houses the electronics required to manage the fuel system, and it routes fuel to the common rail used to make fuel available to the timing and metering actuators.

26. SUMMARY (Cont.) • The timing and metering actuators are electrohydraulic solenoids controlled by PWM actuation by the ECM. • One timing actuator and one metering actuator are used to manage three engine cylinders: A six-cylinder ISX engine uses a total of four actuators: one timing actuator and one metering actuator to manage the front engine cylinders and another pair to manage the rear cylinders. • When energized, each actuator opens to permit rail pressure fuel to pass into the circuit it controls. • The HPI-TP system uses computer-controlled actuators to feed fuel to the timing and metering chambers of an entirely mechanically actuated, open nozzle–type injector. • Two overhead camshafts are used in an ISX engine with HPI-TP fuel system.

27. SUMMARY (Cont.) • The left side camshaft is responsible for actuating the HPI-TP injectors while the right side camshaft is responsible for actuating the valves and the six-stage engine brake. • The ISX engine series that uses HPI-TP injectors is a 15-liter displacement engine that can produce up to 600 BHP (447 kW) and more than 2,000 lb-ft. (2,712 N•m) of torque in its current trim. • These engines weighed less than many of their competitors that output 30% less power. • They use a single slab cylinder head equipped with double overhead camshafts, dedicated to actuating the HPI-TP injectors and the actuation and operation of a six-stage engine brake and the cylinder head valves. • Engines manufactured after October 2002 use cooled EGR to reduce NOx emissions.

28. SUMMARY (Cont.) • Those meeting 2007 emissions standards use DPFs to minimize PM emissions. • All current versions of the ISX use steel trunk-type (Monotherm) pistons. • The fuel flow routing through the IFSM varies with the generation of ISX, so technicians should always consult the service literature in QSOL when troubleshooting. • HPI-TP fueled ISX engines ceased production to North American markets at the end of 2009.

29. Any Questions ? • Thank You !