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Cummins ISB4.5 Specifications
| Engine Model: Cummins ISB4.5 |
| Engine Type: 4-cycle inline 4-cylinder common-rail direct injection liquid-cooled diesel |
| Total Displacement: 275 cu.in (4.5 L) |
| Rated Engine Power: 99-174 Hp (74-130 kW) at 2400 rpm |
| Aspiration Type: Turbocharged and aftercooled |
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| General Technical Data |
The Cummins ISB4.5 is a compact, electronically controlled, turbocharged and aftercooled inline four-cylinder diesel engine engineered for medium-duty trucks, buses, agricultural tractors, construction machinery, industrial power units, and generator sets. As a member of the Cummins ISB engine family, the ISB4.5 emphasizes low emissions, high torque density, smooth operation, fuel efficiency, and exceptional reliability.
Designed to meet stringent global emissions
standards including Euro 3, Euro 4, Euro 5, Tier 3, Tier 4 Interim, Tier
4 Final, and Stage V (depending on version), the ISB4.5 integrates
advanced electronic control, high-pressure common-rail fuel injection,
cooled EGR, and modern air-handling systems. The result is a versatile
engine platform trusted worldwide for both mobile and stationary
applications, offering long service intervals, excellent durability, and
low operating cost.
The Cummins ISB4.5 is a four-stroke, inline four-cylinder diesel engine
with a displacement of approximately 4.5 liters (275 cubic inches). Bore
typically measures 107 mm (4.21 inches), while stroke measures about 124
mm (4.88 inches). The long-stroke configuration provides strong torque
characteristics at low and mid-range engine speeds. Compression ratio
varies slightly across emissions tiers but commonly falls between 16.5:1
and 17.5:1.
Power output ranges from 74 to 130 kW (99–174
horsepower) at approximately 2200–2500 rpm, depending on calibration.
Peak torque typically falls between 450 and 600 Nm (332–443 lb-ft),
usually available at 1500–1600 rpm. Idle speed is usually around 750–800
rpm. The firing order is 1–3–4–2. Electronic turbocharger control, EGR
management, and rail-pressure modulation help achieve high torque
density and emissions compliance.
The cylinder block is constructed from high-strength gray iron for
durability under increased cylinder pressures associated with modern
combustion and emissions technologies. Deep reinforcement ribs improve
rigidity and reduce vibration in industrial or vehicular installations.
The forged-steel crankshaft is supported by five main bearings designed
for long service life under sustained load.
Internal oil galleries and coolant passages are
precisely machined to deliver stable lubrication and heat dissipation.
Piston cooling jets are integrated into the block to regulate piston
crown temperature under heavy-duty cycles. The modular block design
enables flexible mounting of alternators, compressors, hydraulic pumps,
and PTO systems.
The cast-iron cylinder head incorporates direct-injection combustion
chambers optimized for high-pressure common-rail operation. Four valves
per cylinder–two intake and two exhaust–improve airflow and support
efficient combustion. Valves are actuated using pushrods and rocker arms
driven by a camshaft located in the block. Many versions incorporate
hydraulic lash adjusters, reducing the need for periodic valve
adjustment.
Hardened valve seats and heat-resistant guides withstand high temperatures associated with turbocharged and EGR-equipped engines. Advanced combustion chamber geometry improves swirl, atomization, and fuel-air mixing, minimizing soot production and enhancing cold-start performance. Coolant passages integrated into the head help maintain uniform operating temperature.
| Fuel System |
The ISB4.5 uses a modern high-pressure common-rail fuel system. A low-pressure lift pump delivers fuel to a high-pressure pump, which maintains rail pressures typically exceeding 1600–1800 bar (23,200–26,000 psi). Electronically actuated injectors enable multiple injection events–including pilot, main, and post injections–to control combustion, reduce noise, and minimize emissions.
The ECM adjusts rail pressure, injection timing, and injection quantity based on real-time sensor inputs such as crankshaft position, camshaft position, boost pressure, EGR flow, intake temperature, exhaust temperature, and fuel temperature. Fuel filtration includes primary water separators and high-efficiency secondary filters to protect injectors and maintain system longevity.
| Lubrication System |
The lubrication system is a full-pressure wet-sump arrangement driven by a gear-type oil pump. Oil is drawn through a metal strainer, pumped through a full-flow filter, and distributed to main bearings, connecting rod bearings, camshaft bearings, rocker assemblies, and turbocharger bearings. Piston cooling jets help regulate combustion chamber temperatures.
Normal operating oil pressure ranges from 300 to 500 kPa (44–72 psi), while idle pressure is typically between 100 and 150 kPa (15–22 psi). Oil capacity generally ranges from 11 to 13 liters (11.6–13.7 US quarts), depending on sump configuration. Engines equipped with emissions aftertreatment require low-ash oil compliant with emissions specifications.
| Cooling System |
A liquid cooling system maintains thermal stability under varying load conditions. A belt-driven centrifugal water pump circulates coolant through block and head passages. The thermostat begins opening at approximately 82°C (180°F) and is fully open around 95°C (203°F). Cooling system pressure normally ranges from 90 to 110 kPa (13–16 psi).
Coolant capacity typically ranges from 12 to 14 liters (12.7–14.8 US quarts). Charge-air cooling via air-to-air or air-to-water aftercooling reduces intake temperature, improving combustion efficiency and reducing NOx formation. Proper coolant chemistry prevents corrosion, scale, and cavitation while supporting long service intervals.
| Other Systems |
Turbocharging improves intake air density, supporting strong torque and efficient combustion. Depending on version, the ISB4.5 may use wastegated or variable-geometry turbochargers. Charge-air cooling stabilizes intake temperature. The exhaust system may include DOC, DPF, and SCR depending on emissions tier. A cooled EGR system helps reduce NOx emissions.
Electrical systems may operate at 12 or 24 volts, with alternators typically rated between 60 and 120 amperes. The ECM monitors all engine parameters and supports diagnostics, protection strategies, and service alerts. Heavy-duty intake air filtration ensures long-term durability in dusty environments.
| Dimensions and Weight |
Physical dimensions:
Length: 800–1000 mm (31.5–39.4 inches)
Width: 700–800 mm (27.6–31.5 inches)
Height: 900–1100 mm (35.4–43.3 inches)
Dry weight commonly ranges between 430 and 500 kg (948–1102 lbs),
depending on emissions configuration, turbocharger type, and accessory
installation. The compact and modular layout supports use in confined
engine compartments.
| Maintenance Data |
Oil and filter changes are typically recommended every 500 hours or 15,000–25,000 km (9,300–15,500 miles), depending on duty cycle. Fuel filters should be replaced every 500 hours, with water separators drained regularly. Air filter service normally ranges from 250 to 500 hours depending on environmental exposure. Coolant replacement occurs every two years or according to coolant chemistry.
Valve lash inspection may be required on non-hydraulic variants. Aftertreatment components such as DPFs require periodic regeneration and cleaning depending on use. ECM data logs assist with predictive maintenance, troubleshooting, and service scheduling.
| Tightening Torques |
Cylinder head bolts: 180–210 Nm (133–155 lb-ft)
Main bearing caps: 150–180 Nm (111–133 lb-ft)
Connecting rod bolts: 70–90 Nm (52–66 lb-ft)
Flywheel bolts: 220–260 Nm (162–192 lb-ft)
Crankshaft pulley bolt: 240–280 Nm (177–207 lb-ft)
Injector hold-down: 20–25 Nm (15–18 lb-ft)
Intake heaters or glow plugs (if equipped): 10–15 Nm (7–11 lb-ft)
Oil drain plug: 30–40 Nm (22–30 lb-ft).
| Vehicle Applications |
The Cummins ISB4.5 powers medium-duty trucks, buses, agricultural tractors, telehandlers, wheel loaders, excavators, cranes, forestry machinery, industrial power units, generators, and mobile hydraulic systems. Its combination of fuel efficiency, versatility, low emissions, and strong torque output makes it one of the most adaptable engines in its class.
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