instrucciones sistema de combustible qsk60 y 23

Application Engineering Bulletin

Subject This AEB is for the following applications: Generator-Drive HPI-TP & PT Fuel

System Installation Requirements

Automotive Industrial Marine G-Drive Power Generation Filtration Emissions Solution

Date: August 18, 2011 AEB Number 70.28

Engine Models included: QSX15 & QSK 23/45/60/78

Author: A.H.M. (Nur) Nuruzzaman Approver: per Procedure VPI-GAE-0001 Page 1 of 15

This AEB supersedes AEB 70.28

dated July 2, 2010 Introduction The High Pressure Injection (or HPI) fuel systems on QSX15/QSK23/45/60/78 engines offer a number of advantages (including injection timing control) over the Cummins PT fuel system. This bulletin is intended to be a refresher of the basic requirements for the generator set and installation Designer to follow when designing the fuel supply and fuel return systems that connect to the engine. This document will also highlight a few requirements (e.g. fuel cooling) for the HPI-TP (QSX15) and HPI-PT (QSK23/45/60/78) systems. The Designer will need access to Engine Data Sheets and other important documents referenced throughout this bulletin to complete the system design. 1. Fuel Type and Quality The fuel delivered to the engine must satisfy the recommended properties listed in

Cummins Service Bulletin 3379001 (Fuels for Cummins Engines). This bulletin also provides guidelines on filtration, microbial contamination, and fuel additives.

2. Filtration The QSK23/45/60/78 engines have Cummins-supplied and plumbed 10 micron fuel

filters that must be used to protect the engine fuel system. The QSX15 engine has a Cummins-supplied 25 micron fuel filter that must be used

to protect the engine fuel system. A customer-supplied fuel filter/strainer/water separator of 100-120 mesh or

equivalent (approx. 150 microns nominal) is recommended between either the main tank and day tank or between the main tank and the engine.

AEB 70.28 Page 2 of 15

Discussion: Cummins filters are designed to provide the necessary protection to fuel system components while offering an appropriate service life. The customer-supplied filter should not require servicing at shorter intervals than the Cummins-supplied filters (see applicable engine Operation and Maintenance Manual). The added restriction caused by the addition of a customer-supplied filter must be accounted for during the design phase when determining the total fuel system inlet restriction (if fitted to the inlet plumbing of the engine). 3. System Restriction Fuel restriction imposed on the engine by customer-supplied plumbing must not

exceed the limits stated on the Engine Data Sheet at the stated flows. Discussion: Engine performance and fuel system durability will be compromised if the restriction limits are not adhered to. Fuel flow rates for the HPI-TP and HPI-PT are significantly higher than that of the traditional Cummins PT system. The Designer must take care to account for these higher flow rates. The fuel flow is stated in the Fuel System section on the Engine Data Sheet as: Maximum Fuel Flow to Injection Pump Maximum Return Fuel Flow or Maximum Drain Flow

NOTES: 1. Unlike the traditional Cummins PT system, the maximum fuel flows of the HPI-TP and

HPI-PT fuel systems occur at low load where fuel flow requirements for the injector timing chamber is greatest.

2. Also see Table #1 in Section 6 Fuel Line Plumbing for minimum recommended line

sizes, but it is still the Designers responsibility to insure that systems restrictions are acceptable.

a. Fuel Inlet Restriction Limit Fuel inlet restriction must not exceed the limits stated in the Fuel System section on the Engine Data Sheets as: Maximum Restriction at OEM Inlet Connection (QSX15 Engine Data Sheet) Maximum Restriction at PT Fuel Injection Pump (QSK23/45/60/78 Engine Data Sheet)

NOTES: 1. The HPI-TP (QSX15) inlet restriction limit is referenced to the point on the engine

where the customer-supplied plumbing is connected, and therefore, is a true restriction limit for customer-supplied plumbing.

2. HPI-PT (QSK23/45/60/78) inlet restriction limit is referenced to a point downstream of the Cummins-supplied fuel filters. The net available restriction for customer-supplied plumbing is actually the Engine Data Sheet limit less the restriction contribution of the Cummins-supplied filters (1.5 in Hg).


b. Fuel Return Restriction (or Pressure) Limit Fuel return drain restriction (also know as injector return) between the engine injector return line connection and the fuel tank must not exceed the limit stated in the Fuel System section on the Engine Data Sheet as: Maximum Allowable Head on Injector Return Line (Consisting of Friction Head and Static

Head)

NOTE: See the Fuel Tank Design and Location section for more on the effects of tank location on injector return line restriction.

c. Pressurizing the Fuel Inlet and Return Cummins does not recommend the use of customer-supplied circulating pumps to pressurize the fuel supply or return system. The system Designer must make every effort to locate a fuel tank near enough to the engine so that the restriction limits discussed above are not exceeded. 4. Fuel Temperature Fuel Inlet Temperature must not exceed the Maximum Fuel Inlet Temperature limit

stated on the Engine Data Sheet. A fuel cooler is required on QSX15 and QSK23/45/60/78 engines and must be

installed in fuel return line. Fuel heaters are required if ambient temperature is expected to be below the fuel

cloud point. Discussion: The Designer can find the Heat Rejected to Fuel and Maximum Return Fuel Flow on the Engine Data Sheet. There are specialty suppliers for fuel coolers that offer capable products (both for radiator-mounted and remote applications). It is also common for the jacket water cooling system supplier to be able to offer a suitable product. Industrial Application Engineering Bulletin AEB 24.07 is an available reference document on the subject of fuel cooling. 5. Fuel Tank Design and Location The fuel supply tank and day tank construction, size, location, installation, venting,

piping, testing and inspection must comply with all applicable codes. The fuel return connection at the fuel tank must be designed and located to

promote removal of entrained air and be located as far as possible from the fuel supply (to engine) connection point in the tank.

The fuel tank must be properly vented.


The fuel tank must have a drain port for removing water and sediment. The fuel tank must allow for a minimum of 5% expansion space (via fill neck design)

to allow for fuel expansion. The engine fuel supply line connection must be located as far as possible from the

return fuel connection. The pick up point in the tank must be at least 25 mm (1 in) above the bottom of the tank.

The fuel tank must be made of steel (with suitable protective coating) or aluminum.

Galvanized steel or other zinc-bearing materials must not be used. The fuel tank must be located as near as possible to the engine it supplies to

provide the shortest and most direct path for fuel supply and return.

If the machine fuel tank is located so that the maximum fuel level is at or above the level of the engine cylinder head gasket, fuel system with High Pressure Injection (or HPI) on QSX15/QSK23/45/60/78 can allow fuel to enter an engine cylinder by flowing through the fuel lines and an injector after engine shutdown. If fuel enters an engine cylinder, it can cause a hydraulic lock upon startup which can result in severe engine damage. For overhead tank applications check valves must be installed in the fuel supply and return lines to prevent filling a cylinder with fuel during shutdown period. Tier 2 and Tier 3 QSX15 engines with HD (Heavy Duty) HPI (High Pressure Injection) and overhead tanks must have additional protection against fuel drainback. The fuel system must have a check valve in the fuel return line and OEM-supplied shutoff valve in the fuel supply line. A quality electronic solenoid valve is recommended for the inlet shutoff. For additional protection, a 50 micron filter element can be installed in the supply line between the solenoid valve and the fuel tank. The filter will prevent large contaminants from getting to the solenoid valve and IFSM.

Maximum allowable height of fuel above crank centerline to prevent hydraulic lock

is 2.1m (7 ft). Note: Fuel friction head must be accounted for in addition to line restrictions. (See sample calculation in Section 7)

Maximum lift capability of fuel from below crank centerline.

QSX15 = 91 cm (36 in) QSK23/45/60/78 = 107 cm (42 in)

Note: Fuel friction head must be accounted for in addition to line restrictions. Applications where the engines are used in gensets that are to be paralleled or that

must satisfy specific emergency start-time requirements must have a fuel tank located such that the lowest possible fuel level is not less than 15 cm (6 in) above the fuel pump inlet. This will prevent air from accumulating in the fuel supply line when the engine is not in use. (See Figure 2B)


Discussion: A fuel supply system includes one or more storage tanks sized to support an acceptable refueling interval (typically 1 to 5 days). The demands of a relatively long refueling interval must be balanced against concerns about the storage of large quantities of fuel and the potential for microbial growth. In the U.S., the National Fire Protection Association (NFPA) 110 standard describes tank sizes for emergency systems. Also, NFPA 37 defines on-site fuel supply requirements. a. Local Codes Many installation sites are subject to regulations concerning the design, size, location, installation of the main fuel storage tank as well as float tanks/day tanks. The fuel tanks used must conform to all applicable codes. b. Fuel Return Connection Return fuel from the engine contains significant amounts of entrained air that must be removed in the tank before the air is pulled into the engine supply line. The location and the design of the fuel return connection can promote air removal from the fuel. There are 2 possible alternatives for the design of the return connection arrangement for HPI-TP and HPI-PT fuel systems:

1. Preferred Above Fuel Level Method (traditional Cummins PT Method): The fuel tank return connection is designed such that the fuel is returned above the maximum fuel level in the tank. This method has proven effective for removing entrained air. A baffle is recommended to further improve the removal of entrained air. (Figure 3)

NOTE: This method is acceptable for all tank sizes, but especially important for tanks where fuel return and fuel supply connections are 1.5 m (5 ft) or less distance from each other (e.g. day tanks).

2. Alternate Below Fuel Level Method (traditional B/C Series engine Method):

The fuel tank return connection is designed with a drop tube, which delivers the return fuel to near the bottom of the tank (below the lowest possible fuel level).

NOTE: This method is acceptable for large tank sizes (e.g. subbase tanks) where the fuel return and fuel supply connections are more than 1.5 m (5 ft) apart.

c. Tank Vent or Breather The tank should be vented adequately to prevent system pressurization. As stated earlier, the HPI fuel systems operate with higher fuel flow rates than previous systems and the return fuel contains significant amounts for entrained air that must be removed. The vent must be designed such that debris and water cannot enter the tank. Follow the requirements of the applicable local codes with regard to where and how the vent is plumbed to the atmosphere.


d. Tank Water and Sediment Drain The fuel tank must have a drain port for conveniently removing water and sediment from the bottom of the tank. A valve is much more practical than a pipe plug. e. Tank Fill Neck and Expansion Space The fuel tank must allow for a minimum of 5% expansion space (via fill neck design) to allow for fuel expansion. The fill neck must extend into the tank as shown in Figure #1 & #2. f. Engine Fuel Supply Connection The engine fuel supply line connection must be located as far as possible from the return fuel connection. The pick up point in the tank must be at least 1 in (25 mm) above the bottom of the tank. The pick up tube must be well supported inside the tank to withstand vibration (cracks will allow air to be pulled into the engine). g. Tank material The fuel tank must be made of steel or aluminum with a protective coating proven to be suitable with diesel fuel. Galvanized steel or other zinc-bearing materials must not be used. The zinc reacts with diesel fuel to form a substance that can damage the fuel system. h. Sight Glass (optional) If a sight glass is fitted to the tank, it must be made of unbreakable material and/or protected with guards to prevent damage. Also, it must be fitted with shut-off valves on each end of the tube. It is recommended that these valves be closed except when checking fuel level.


Fuel Tank

Drain Opening 25 mm (1 in)

Breather

Sight Glass

Fuel return

Fuel Supply

Min. Fuel level

Crank Centerline

QSX15 = 91cm (36in) QSK23/45/60/78 = 107cm (42in)

Fill Opening

Approved Flexible Fuel Hose


All piping to be Black Iron

Figure 1: Typical Fuel Tank below Fuel Inlet

Fuel Tank Fuel Return

Fuel Supply

Figure 2: Typical Fuel Tank above Fuel Inlet

Drain Opening

Fill Opening Breather

Sight Glass

25mm (1 in)

Crank Centerline

2.1 m (84 in)

Max Fuel Level




5% Expansion space


Fuel Tank

Fuel Return

Fuel Supply

Figure 2B: Typical Fuel Tank above Fuel Inlet (emergency start requirements)

Drain Opening

Fill Opening

Breather

Sight Glass

Max Fuel Level




5% Expansion space

25mm (1 in) 152mm (6 in)

Minimum Fuel level above pump inlet

Fuel Supply to engine

Fuel supply drop tube with filter screen 25 mm (1 in) off bottom of tank

Fuel supply to Day Tank

Return fuel from engine

Breather

Drain Opening

Float switch to control fuel level in Day Tank

Baffle to permit deaeration of fuel

Figure #3: Float Tank Requirements

Overflow return to bulk tank

Fuel level sight glass


6. Fuel Line Plumbing (Supply and Return) All rigid lines must be black iron pipe or steel tubing. All flexible lines must be diesel fuel compatible and rated for 1720 kPa [250 PSI]

working pressure, vacuum of 250 mm Hg [10" Hg] and an operating temperature range of at least-40 C to 120 C [-40 F to 250 F]. (Ref. SAE J30R7)

Flexible lines must be used to connect the rigid fuel lines to the engine. All plumbing must be well supported and allow for thermal expansion, vibration and

other component motion. Fuel shut-off valves are not permitted in the return line. Separate return lines must be provided for each engine in a multiple-engine

installation. Also, the return lines must not be plumbed with the return or supply fuel of any other equipment.

All fuel lines must be adequately flushed before they are connected to the engine. Discussion: Fuel line plumbing is required to supply fuel to the engine and to return fuel from the engine. Black iron pipe or steel tubing are required for rigid plumbing. If black iron pipe is used, a thread sealant must be used in place of Teflon tape. Copper lines are not recommended because of their susceptibility to fatigue cracking. The copper can also react with diesel fuel to form a gummy substance. The Designer must develop a plumbing layout that avoids loops and high spots where air can accumulate in the lines. Ideally, all lines should run uphill toward the tank to allow air to vent to the tank when the engine is not running. The following table summarizes the minimum recommended fuel line sizes for a given range of flow rates. Note: Programs such as Cummins Advisor, Toolbox, or other acceptable calculations are recommended to determine required line size for a specific application.

Table #1: Fuel Flow vs Fuel line size Line length < 3m (10 ft)

Supply Return Max Fuel Flow rate GPH (L/hr)

Flex Hose I.D. in (mm) Flex Hose I.D in (mm)

Less than 80 (303) No. 8 0.500 (12.7) No. 8 0.500 (12.7) 81-100 (304-378) No. 10 0.625 (15.9) No. 8 0.500 (12.7) 101-160 (379-604) No. 10 0.625 (15.9) No. 10 0.625 (15.9) 161-230 (605-869) No. 12 0.750 (19.1) No. 10 0.625 (15.9) 231-310 (870-1170) No. 12 0.750 (19.1) No. 12 0.750 (19.1) 311-410 (1171- 1550) No. 16 1.00 (25.4) No. 12 0.750 (19.1) 411-610 (1550-2309) No. 20 1.25 (31.8) No. 16 1.00 (25.4) 611-920 (2309-3480) No. 24 1.50 (38.1) No. 20 1.25 (31.8)

AEB 70.28 Page 10 of 15

Table #1: Fuel Flow vs Fuel line size

(continued) Line length 3m - 15m (10 - 50 ft)

Supply Return Max Fuel Flow rate GPH (L/hr)

Flex Hose I.D. in (mm) Flex Hose I.D in (mm)

Less than 80 (303) No. 10 0.625 (15.9) No. 8 0.500 (12.7) 81-100 (304-378) No. 10 0.625 (15.9) No. 10 0.625 (15.9) 101-160 (379-604) No. 12 0.750 (19.1) No. 10 0.625 (15.9) 161-230 (605-869) No. 12 0.750 (19.1) No. 12 0.750 (19.1) 231-310 (870-1170) No. 16 1.00 (25.4) No. 12 0.750 (19.1) 311-410 (1171- 1550) No. 20 1.25 (31.8) No. 16 1.00 (25.4) 411-610 (1550-2309) No. 24 1.50 (38.1) No. 20 1.25 (31.8) 611-920 (2309-3480) No. 24 1.50 (38.1) No. 24 1.50 (38.1)

Bulk Storage/Make-up Tanks (Figures #4 & #5)

Must include valves to control and shut off make-up flow Must include equipment to prevent Day Tank Overfilling Must include fuel filters in transfer lines Transfer piping must not be capable of siphoning fuel from Day Tank Bulk Storage or Make-Up Tanks are sized to support the acceptable refueling interval. Typically Bulk Storage or Make-Up tanks are located remote from the engine. When Bulk Storage Tanks are located such that their fuel levels are higher than the fuel level in the Day Tank(s), gravity can be used to transfer fuel to the Day Tank(s). One or more valves is required to control and shut off this make-up flow. The installation must include a method of preventing overfilling of the Day Tank(s). When Bulk Storage Tanks are located such that their fuel levels are lower than the fuel level in the Day Tank(s), a transfer pump must be utilized to move fuel to the Day Tank(s). A check valve should be provided to ensure fuel in the transfer line does not drain back to the Bulk Fuel Storage tank.

AEB 70.28 Page 11 of 15

Baffle

Note: The fuel supply, day tank or other reservoir must be arranged so that the highest fuel level does not exceed the maximum height above the crank centerline specified for the engine. The lowest level must not fall below the specified lift height of the engine fuel pump. Applications where the engines are used in gensets that are to be paralleled or that must satisfy specific emergency start-time requirements must have a fuel tank located such that the lowest possible fuel level is not less than 15 cm (6 in) above the fuel pump inlet. This will prevent air from accumulating in the fuel supply line when the engine is not in use. See Figure #2B

5% Expansion Space (minimum)

Fuel Supply Tank

Screened Vent Cap (outside)

Construction, location, installation, venting, piping, leak containment, and inspection must comply with all applicable codes.

Approved Day Tank

Fuel Supply piping

Fuel Return piping


Float Switch

Screened fill cap (outside)

Float switch operated Siphon-break Solenoid valve

Manual shutoff valve

Float switch operated solenoid valve

120 Mesh fuel strainer

Manual priming ball valve-Self closing

Approved flexible fuel hoses from Iron pipe to Return and Supply fittings

Screened vent cap (outside)

Approved Day Tank

Fuel Supply piping

Fuel Return piping


Float Switch

Approved flexible fuel hoses from Iron pipe to Return and Supply fittings

5% Expansion Space (minimum)

Fuel Supply Tank

Construction, location, installation, venting, piping, leak containment, and inspection must comply with all applicable codes.

Overflow pipe-One pipe diameter larger than supply

Pump, Solenoid Valve and 120 mesh Fuel Strainer

Auxiliary pump if required

Screened vents Fill Cap

Note: The fuel supply, day tank or other reservoir must be arranged so that the highest fuel level does not exceed the maximum height above the crank centerline specified for the engine. The lowest level must not fall below the specified lift height of the engine fuel pump. Applications where the engines are used in gensets that are to be paralleled or that must satisfy specific emergency start-time requirements must have a fuel tank located such that the lowest possible fuel level is not less than 15 cm (6 in) above the fuel pump inlet. This will prevent air from accumulating in the fuel supply line when the engine is not in use. See Figure #2B

Figure #5: Remote Fuel Supply Lower then Day Tank

Figure #4: Remote Fuel Supply higher then Day Tank

Baffle

AEB 70.28 Page 12 of 15

7. Testing Static Head Pressure Calculation Many questions arise concerning an engine's drain line restriction and overhead fuel height limits. The two questions are related and thus were combined under a common heading on the Engine Data Sheet: "Maximum Allowable Head on Injector Return Line, consisting of Friction Head and Static Head. This means that Friction Head + Static Head = Maximum Allowable Head Example: Maximum Allowable Head on Injector Return Line" = 6.5 in Hg (165 mm Hg) Fuel return line is routed 5ft (1.5 m) above injectors. 5ft Fuel x 12 in X 1in Hg = 3.7inHg (94 mm Hg)

Ft 16.3in Fuel The fuel drain line restriction must then be less than: 6.5 in Hg (165 mm Hg) - 3.7 in Hg (94 mm Hg) = 2.8 in H (71 mm Hg)

Fuel Line Restriction Measurement When: At engine commissioning/Installation review Whenever engine performance appears to be degraded due to restriction

Checking Fuel Inlet Restriction on QSK23/45/60/78 engines

HPI-PT Fuel Pump and Pressure Regulator Assembly

Fuel Inlet from filters

Fuel Outlet to Electronic Fuel Control Valve

Max allowable restriction with clean filters @ CompuCheck fitting = 4 in Hg (102 mm Hg)

Compucheck fitting on the fuel pump

AEB 70.28 Page 13 of 15

Operate the engine at the data sheet recommended loads and speeds when taking the measurements. Several minutes of operation may be required to purge air and other accumulated vapors from the system and for the readings to stabilize.

Checking Return Fuel Restriction on QSK45/60

Compucheck fitting located @ front of engine by Engine Data Plate Max allowable fuel return restriction @ Compucheck fitting = 9 in Hg (228 mm Hg)

Checking Fuel Inlet Restriction on QSX15

Customer Fuel Inlet Hose

IFSM

Allowable restriction @ IFSM OEM Fuel Inlet Connection = 3 in Hg (76 mm Hg)

Customer Fuel Inlet Connection

AEB 70.28 Page 14 of 15

Fuel Quality Measurement

At engine commissioning Whenever changing fuel suppliers Whenever fuel suppliers indicate fuel quality may change Whenever changing fuel type Whenever engine performance appears to be degraded due to fuel quality Contact your local Cummins Distributor for assistance with fuel quality testing.

Customer Fuel Return Connection

Customer Fuel Inlet Connection Customer Fuel Return Hose

IFSM Allowable restriction @ IFSM OEM Fuel Return Connection with IFSM mounted filter = 6 in Hg (165 mm Hg)

Checking Fuel Return Restriction on QSX15

AEB 70.28 Page 15 of 15

Reference and Related Documents The following documents contain additional information that may be useful when installing or operating a fuel system: Bulletin No. Description 3379001 Fuels for Cummins Engines 3382409 Construction, Mining, Logging, Agriculture and Stationary Power

Installation recommendations Fuel Systems NFPA 30 Flammable and Combustible Liquids Code NFPA 70 National Electric Code NFPA 99 Health Care Facilities Code NFPA 101 Life Safety Code NFPA 110 Emergency and Standby Power Systems AEB 70.23 Fuel System Installation Requirements for Emergency Generator Sets AEB 24.07 Fuel cooling installation recommendations

Change Log

Date Author Description Page(s)

18Aug2011 A.H.M. (Nur) Nuruzzaman

Updated Approver number in header. Added information for overhead tank applications. Added requirements on Tier2/Tier3 QSX15 fuel system

supply and return lines for drainback protection.

1 4 4

July 2, 2010 A.H.M. (Nur) Nuruzzaman

Updated Introduction and Reference Documents. 1, 15

July 9, 2009 Emmanuel Padilla

Updated format and moved images so they would appear on page.

1, 6, 7

Nov. 4, 2004 Norm Jones Initial Release