Usage:
This section contains specific recommendations and general information for major operating systems regarding the 3176B Industrial Engine.
- * Air Inlet System
- * Air to Air Aftercooler System
- * Exhaust System
- * Fuel System
- * Lubrication System
- * Cooling System
- * Engine Support Systems
- * Air to Air Aftercooler System
Air Inlet System
The function of the air inlet system is to supply an adequate amount of clean, dry, low temperature air to the engine.
Caterpillar offers air cleaner systems with their 3176B Industrial engine offerings. These are sized to the CFM requirements for a specific power and speed rating. The following is offered where an alternate OEM supplied system is chosen.
The pressure drop restriction across an adequately sized air cleaner will be 1.5 kPa (6 inches of H2O) when clean. System inlet air piping may add an additional 0.75 kPa (3 inches of H2O) restriction. Thus, this system will have an initial 2.2 kPa (9 inches of H2O) overall system restriction when clean, and is an important indicator for air cleaner element service life. Dirty element change interval occurs when 6.2 kPa (25 inches of H2O) restriction occurs. Higher inlet system restrictions caused by either an undersized air cleaner or too restrictive air cleaner piping will result in foreshortened cleaner change intervals.
Maximum recommended clean air induction system restriction is 3.7 kPa (15 inches of H2O).
Maximum dirty air cleaner restriction 6.2 kPa (25 inches of H2O).
Service indicators are vacuum sensing devices which tell the operator when air cleaner restriction has reached the service or change element operating interval.
Air Cleaners
Two stage air cleaners are recommended for most industrial applications. This offers additional service life in dirty and dusty environments. The design incorporates an additional secondary element which remains undisturbed during primary element change periods. Dirt retained within the air cleaner housing or which may be bumped off the primary element during filter change is trapped by the secondary element at diesel engine restart.
Oil Bath Air Cleaners
Oil bath air cleaners are not recommended for diesel engine operation. They are sometimes called for in older specifications. Take exception, and rely on dry type air cleaners. Oil bath cleaners are less efficient, operate poorly or not at all in cold weather environments, become ineffective when oil level diminishes, have an efficiency level of 95 percent at maximum, and can cause oil carry over resulting from overfilling or increased inlet air flow.
Inlet System
Shielded against direct entrance of rain or snow. Common practice is to provide a rain cap or pre-cleaner.
Both pre-cleaners and pre-screeners are used in very dirty environments to ward off agricultural chaff, rock crusher silicon laden air, or any damaging airborne contaminant heavy enough to be removed by swirl type ejection prior to reaching the actual air cleaner filtration element.
Several pre-cleaner systems are available on the OEM market. One such system has been selected by Caterpillar as an air pre-cleaner option for Caterpillar construction machinery. This is known as the "Sy-Klone" pre-cleaner. It is available to meet a variety of CFM inlet air requirements and can be adapted to Caterpillar industrial engines.
Inlet air piping should be located to ingest the cleanest coolest ambient air possible. Exhaust stack location should not contribute to "recirculation" of exhausted air to the clean air inlet pick up point. Pipe diameter should be as large as the turbocharger air inlet pipe.
Avoid wire reinforced flexible hose as inlet piping. This is susceptible to damage from abrasion, abuse, and is very difficult to seal effectively at the hose clamping points. Avoid plastic tubing of any type. Plastic tubing will lose much of its physical properties when subjected to underhood temperatures which can reach 149°C (300°F).
Bracing or supports are required if an unsupported air cleaner assembly exceeds 27 N·m (20 lb ft) bending moment at the turbocharger inlet pipe casting. Unsupported weight at clamp type joints should not exceed 1.4 Kg (3 lb).
A straight pipe section before turbocharger inlet of two to three times pipe diameter is desired to assure that air is flowing in a straight uniform direction as it enters the turbocharger compressor.
Air To Air Aftercooler (ATAAC or Charge Air Cooling)
Air to air aftercooling improves fuel consumption and reduces exhaust gas emissions to meet current and future governmental regulations. Its function is to reduce inlet manifold air temperature as much as possible within the normal working range of the machine. Each OEM machine will have unique installation requirements to accommodate an ATAAC system.
Reputable radiator system suppliers offer a variety of ATAAC core systems. Three types are commonly used. One is the independent core mounted in front of a regular engine radiator core. A second version incorporates an integral ATAAC core built into the top of a regular radiator section. This dual core arrangement usually has a cross flow engine coolant core. The top 1/3 of the core frontal area is occupied by the ATAAC core, with the remaining 2/3 dedicated to the engine cooling system. A third variation is a side by side arrangement. If the OEM product has sufficient frontal area to accommodate these latter designs, it can simplify ATAAC core plumbing and mounting.
An ATAAC core should guarantee minimal charge air leakage. This can be tested by pressurizing the core to 207 kPa (30 psi). It should hold this pressure and not exceed a 28 kPa (4 psi) pressure drop within 15 seconds.
Consult the Technical Marketing Information Data or Engine Data sheet for specific BTU heat rejection which must be rejected for a given 3176 horsepower rating.
As a rule of thumb, conservative ATAAC heat rejection calculations can be approximated by multiplying rated engine horsepower times 9 BTU/min. Thus, a 365 hp, 3176B engine, would need an ATAAC core capable of rejecting about 3285 BTU/min.
Generally, ATAAC core air ducting is made of aluminized steel or aluminum pipe material. It can be from 76 mm (3.0 in) to 114 mm (4.5 in) in diameter. Typically, it will be no smaller than the turbocharger compressor outlet duct. The key element in both air core ducting and ATAAC core selection is to assure the total charge air pressure drop does not exceed 12.5 kPa (3.7 inches of Hg). This is measured from turbocharger outlet elbow P1 to P2 air inlet manifold. (See accompanying Charge Air System schematic).
Duct connections are, typically, heat resistant silicon hump type hoses. They are capable to supply the needed flexibility and durability for long hose life. It is recommended the selected hoses be capable of a 276 kPa (40 psi) proof pressure at 177°C (350°F), plus a minimum burst pressure of 689 kPa (100 psi) at 316°C (600°F). Plastic, rubber, or wire reinforced hose is unacceptable in the charge air system as a connection device. Use constant torque clamps to fasten hoses. Dual clamping is recommended at each joint to assure a positive seal clamping.
Maximum temperature rise from ambient air temperature to turbocharger inlet is -7°C (20°F). (Example, ambient 38°C (100°F), turbo inlet 49°C (120°F).)
Maximum temperature of air to the inlet manifold should not exceed 6°C (43°F) between ambient air temperature T1 and inlet manifold point T5. Rated engine power is developed to up to 49°C (120°F) inlet manifold temperature. As inlet temperature increases beyond this point, engine power will reduce.
NOTE: Radiator shutters are not recommended.
In extreme cold weather operations a winter front or radiator shutter may be used provided that a permanent air flow opening of 77,419 mm2 (120 in2) is allowed for charge air cooling purposes. This opening should be obtained by having several smaller openings across the core frontal. This is done to reduce thermal shock to the ATAAC core.
Exhaust System
Exhaust gas flow restriction is created by a combination of the exhaust system piping, muffler or silencer and any system catalytic converter, scrubber or filter being used. Total system backpressure must not exceed 6.7 kPa (27 inches of H2O) at rated engine conditions. Excessive restriction causes reduced power, lack of engine response, excessive exhaust temperatures, and engine exhaust valve damage.
Consult the Industrial Installation and Application Guide for details regarding exhaust system calculations before finalizing exhaust system design. Pressure drop (backpressure measured in kPa (inches of H2O), total equivalent length of exhaust piping in meters (feet), exhaust gas flow in cubic millimeters per minute (cubic feet per minute), inside diameter of pipe, and exhaust temperatures are used to estimate exhaust system back pressure.
Maximum allowable exhaust system static bending load that can be carried by the turbocharger exhaust elbow is 27 N·m (20 lb ft). If this bending moment is exceeded, provide a support.
Fuel System
The connection points for both fuel supply and return are provided on the engine. Flexible connectors are recommended to accommodate relative engine movement during operation in the OEM machine.
Fuel tank construction can be steel or aluminum. Fuel pump suction line should be located above the tank bottom to allow approximately 5 percent of the tank volume for sediment and water collection. A tank sediment drain valve should be provided, and a filtered tank vent is recommended to minimize dust in the fuel tank.
The 3176B is equipped with a gear-type fuel transfer pump. In all installations, a primary fuel filter (such as a Racor filter) must be installed between the fuel tank and fuel transfer pump.
A secondary Caterpillar fuel filter is used. This should incorporate the Caterpillar hi-efficiency 1R0749 Fuel Filter to protect fuel system injectors.
Fuel Cooler Requirements
The 3176B electronic control module (ECM) is cooled by diesel fuel flowing to the engine. Fuel is routed from the fuel tank, to primary fuel filter, through the fuel transfer pump, to cored passages on the ECM, on to the secondary filter, to the injection pumps and finally back to the fuel tank. This fuel system incorporates a constant flow relief valve which returns approximately 4.2 L (1.1 gal U.S.) of fuel to the fuel tank per minute. Fuel temperature can increase approximately 16°C (60°F) to 21°C (70°F) as it flows through the engine. Fuel inlet temperatures at the fuel transfer pump must not exceed 79°C (175°F). If fuel temperatures consistently exceed this limit, a fuel cooler is required in the return fuel flow circuit. Higher temperatures will reduce the life of the electronic control module and decrease engine performance.
Lubrication System
Engine Data Sheets provide oil system capacity, high and low sump levels, normal oil system pressure, and engine crankcase oil specifications. Some OEM installations require a modified oil level gauge due to engine installation angle or tilt. In these cases, it is an OEM responsibility to reestablish proper oil level markings for "add oil" and "full" indicators. Typical lube oil capacity is 30 L (32 qt) "full" and 34 L (36 qt) to the "add" mark.
Cooling System
Refer to Engine Data Sheet (EDS) 50.5 and appropriate supplemental cooling system EDS for details to conduct a cooling system audit. This facet represents an entire procedure to evaluate effectiveness of the engine jacket water cooling system. It will give an accurate indicator of Maximum Ambient Capability which the installed cooling system will provide for the engine rating being tested.
NOTE: Control system voltage can be 12 or 24 volts.
Engine Support Systems
Typical OEM engine mounting uses the "three point system", where a front single mount is provided under the crankshaft pulley, and two rear supports are provided on either side of the flywheel housing. The standard aluminum flywheel housing has angled support mounting pads.
The three point mount normally is capable of allowing large amounts of machine frame torsional deflection without imparting undue stress to either the mounting pieces or engine structure.
Overhung transmission or torque converter loads on the aluminum flywheel housing must not exceed 16,320 N·m (12,000 lb ft). This maximum bending moment can readily be exceeded in OEM mobile machinery which is subject to rough terrain, sudden jolts such as found in wheel loader applications, and machinery which may operate by radio remote control. High "G" force loadings must be considered before allowing an unsupported overhung load situation.
A third mount is sometimes needed on the unsupported overhung load. Some transmissions and converter housings have provisions for mounting pads which can be used to support the rear of the engine. Using this mount can be very beneficial. It reduces the overhung mass and may eliminate the need for an additional support. A note of caution is necessary when using transmission/converter mounting pads for rear engine support. Machine "G" loadings may impart a reverse bending moment at the flywheel-engine block bottom interface, which can be just as unsatisfactory as an unsupported rear overhung mass.
Industrial Engine Sensor And Connector Locations
Sensor and Connector Locations.
Industrial Engine Electronic System Components
Electronic Control System Components.
Wiring Schematic
