Details
Cummins 4B3.9-G2 24kW Diesel Engine: Genuine DCEC G-Drive Supply
The Cummins 4B3.9-G2 is a compact 3.9L four-cylinder diesel engine developed for generator set applications requiring stable 50Hz output at 1500RPM. Manufactured by Dongfeng Cummins Engine Co., Ltd. (DCEC), this naturally aspirated G-drive engine is widely used in small industrial generator sets, telecom backup systems and standby power installations.
Compared with electronically controlled engines designed for high-horsepower applications, the 4B3.9-G2 focuses on operational simplicity, stable fuel delivery and low maintenance requirements. These characteristics make the engine suitable for regions where fuel quality, operating temperature and maintenance conditions may vary significantly.
HekoPower supplies complete engine assemblies for OEM generator manufacturers, equipment distributors and export customers requiring reliable power solutions for continuous or standby operation.
Tech Specs of Cummins 4B3.9-G2
General Engine Data
Engine Model: Cummins 4B3.9-G2-24kw
Type: 4 Cylinders in Line, 4 Stroke Diesel
Displacement: 3.9 L
Bore * Stroke: 102 * 120
Net Weight: 308 Kg
Overall Dimension: 867mm*544mm*988mm
Key Performance Data
Rated Power/Standby Power: 24 kW/32HP, 27 kW/36HP
Rated Speed: 1500 rpm
Low Idle Speed: 950-1050 rpm
Fuel Consumption (Running Speed): ≤ 275 g/kW.hr
Torque @ Rated/Standby Output: 153/172 N.m @ 1500 rpm
More Technical Data
Aspiration: Natural Aspiration
Fuel System: BYC A Pump/RSV
Compression Ratio: 16.6:1
Electrical System (Starter Motor/Alternator): 12V/24V
Lowest Starting Temp Without auxiliary system: -12℃
Cooling Method: Water cooled
Engine Cooling Fluid Volume: 7.2 L
Governor Type: Electronic, Regulation ≤5%
Technical Blueprint & Engineering Advantages
The 4B3.9-G2 G-Drive engine utilizes a heavy-duty, cast-iron block design with four inline cylinders, featuring a 102 mm bore and a 120 mm stroke. This configuration creates a total displacement of 3.9 liters, offering superior structural mass compared to lighter aluminum engines in the same power band. This added mass reduces vibration profiles during high-load power delivery, protecting connected electrical alternators from torsional fatigue.
Fuel Delivery via BYC A-Pump Architecture
This Cummins 3.9L 24kw engine with BYC fuel pump utilizes a rugged mechanical direct-injection system. The inline BYC A-pump operates in tandem with an RSV mechanical governor to provide precise fuel metering relative to instantaneous load shifts. Because it avoids complex Electronic Control Units (ECUs) and common-rail electronics, the mechanical governor Cummins generator engine resists electrical interference and tolerates varied fuel qualities. This feature is particularly valuable in regions with less refined fuel supplies.
Fuel Consumption Profile at 1500RPM
Operational economics depend directly on predictable fuel burns across different duty cycles. For a standard 50Hz configuration, the Cummins 4B3.9-G2 engine fuel consumption at 1500RPM breaks down into highly predictable metrics:
- 100% Prime Load: Approximately 6.7 liters per hour (L/h).
- 75% Prime Load: Approximately 5.1 liters per hour (L/h).
- 50% Prime Load: Approximately 3.6 liters per hour (L/h).
Maintaining operations within the 75% to 100% load band maximizes thermal efficiency. This range prevents "wet stacking," a condition where unburnt fuel accumulates in the exhaust tract due to low combustion chamber temperatures.
Comparative Engineering Analysis
Selecting the proper engine layout requires understanding how a naturally aspirated 3.9L system compares to specialized alternatives within the B-series lineup.
Naturally Aspirated 4B3.9-G2 vs. Turbocharged 4BT3.9
The primary differentiator between the 4B3.9-G2 and the 4BT3.9 variant centers on aspiration mechanics. The 4B3.9-G2 draws intake air under ambient atmospheric pressure. This removes the risk of turbocharger bearing failures, oil seal degradation, and transient response delays during sudden block loading. While the turbocharged 4BT3.9 offers a higher power-to-weight ratio, the naturally aspirated 4B3.9-G2 provides a reliable alternative for constant 24kW outputs. It avoids the elevated exhaust gas temperatures (EGT) common in forced-induction systems.
Application Profiling: 4B3.9-G2 vs. 4B3.9-G1
The distinction between the G2 and G1 variants lies in their Governor Regulation Class and target power outputs. The G2 variant features an upgraded mechanical governor calibration optimized for a 24kW continuous load. This enables tighter frequency control (under 5% droop) during 30 kVA alternator coupling. The G1 variant is typically reserved for lower power thresholds or less demanding standby applications where transient recovery times are less critical.
Global Deployment & Environmental Adaptability
The 4-cylinder industrial diesel engine for standby generator sets is built to maintain steady power outputs across a wide range of operating conditions.
Remote Telecom Tower Infrastructure
Telecom operators deploy this Cummins generator engine for telecom backup power across vast off-grid networks. Telecom base stations require stable, continuous power for transceivers, often in remote, unmanned locations. The 4B3.9-G2 serves as a durable off-grid prime power source, operating reliably for extended, unattended service intervals of up to 250 hours between standard oil changes.
Agricultural and Irrigation Management
In farming applications, this diesel engine for agricultural standby power systems drives deep-well turbine pumps and automated line-linear irrigation setups. Its high low-end torque allows the engine to handle the initial hydrodynamic resistance of starting water columns without stalling, providing steady torque at 1500RPM.
Extreme Thermal and Tropical Operations
The Cummins B3.9 generator engine for tropical climate operation features an oversized cooling package. The Cummins 4B3.9-G2 radiator and cooling system configuration is rated for ambient temperatures up to 50°C. This prevents thermal de-rating in hot climates, such as the Middle East and Southeast Asia, by ensuring efficient heat dissipation even when enclosed inside acoustic, silent genset canopies.
Maintenance, Lifecycle Management & Retrofitting
Long-term cost efficiency depends on proper maintenance schedules and a solid understanding of component wear cycles.
30kVA Alternator Coupling Realignment
When configuring a 4B3.9-G2 G-Drive engine for 30 kVA alternator coupling, precision alignment along the crankshaft centerline is critical. Technicians must use a dial indicator to check both radial and axial runout at the flywheel housing interface, keeping variance under 0.05mm. Misalignment can create axial load imbalances, leading to premature rear main seal leaks or main bearing wear.
Scheduled Fluid and Filter Replacements
To maximize engine lifespan, operational teams should follow a strict preventive maintenance schedule:
- First 50 Hours: Perform the initial break-in oil change and clean the suction screen.
- Every 250 Hours: Replace the primary lubricating oil filter, fuel water separator, and top off the 7.2-liter cooling system with a 50/50 glycol mix.
- Every 1000 Hours: Adjust the valve clearance (Intake: 0.25mm; Exhaust: 0.51mm) to sustain fuel efficiency and clean the BYC injection nozzles.
Supply Chain Logistics & Global Distribution
As a direct exporter, HekoPower coordinates complete equipment logistics from factory floor to final destination ports.
Pricing Structures and FOB Terminology
We offer competitive Cummins 4B3.9-G2 24kw engine export prices tailored to bulk ordering profiles. Standard commercial transactions are handled under Cummins 4B3.9-G2 engine FOB Shanghai terms. This approach ensures transparent cross-border documentation, certified export clearances, and safe handling before loading onto international container vessels.
Lead Times, Enclosures, and Packaging Protocols
Every engine assembly is preserved with anti-corrosion oil coatings, wrapped in heavy-duty poly-sheeting, and secured inside a rugged, export-grade IPPC wooden crate. Our typical Cummins 4B3.9-G2 engine lead time ranges from 15 to 25 days from deposit confirmation to port delivery. This efficient turnaround supports quick replacement schedules for urgent infrastructure projects.
Cummins B3.9-G Series, original products from Dongfeng Cummins Engine Plant (DCEC), Cummins Joint Venture Plant since 1986, 50% shareholding by Cummins USA. This series mainly includes 4B3.9-G1-24kw, 4B3.9-G2-24kw, 4BT3.9-G1-36kw, 4BT3.9-G2-36kw, 4BTA3.9-G2-50kw, 4BTA3.9-G2-58kw, 4BTA3.9-G11-70kw.In accordance with the criteria of Machinery Safety Directive 2006/42, movable elements such as distribution belts, fans, and parts that acquire high temperatures during operation, such as exhaust manifolds, have their respective safeguards. Before being delivered, the generator is thoroughly checked at the factory. Voltage, frequency, and load are all tested, as well as the appropriate operation of warnings and the influence of engine oil temperature on stop.
Product Technical FAQ
Can the 4B3.9-G2 run continuously at 1800RPM for 60Hz power generation?
Yes. While optimized for 1500RPM (50Hz), the DCEC Cummins 4B3.9-G2 G-Drive engine can be recalibrated via governor adjustments to run at 1800RPM. This modification increases the standby output to roughly 27kW to match 60Hz grid requirements in North American and specific South American markets.
Does the engine assembly include a radiator and control panel?
HekoPower supplies this unit as a complete mechanical power pack. Customers can buy the Cummins 4B3.9-G2 engine with a pre-mounted radiator, cooling fan, safety guards, and integrated dry-element air cleaner assembly. Control panels can be added based on project specs.
How does the mechanical governor handle sudden electrical block loads?
The RSV mechanical governor reacts to sudden load drops or spikes within 3 to 5 seconds. It adjusts the fuel rack position inside the BYC inline pump to maintain stable engine speeds and prevent hazardous frequency drops across your electrical systems.
What certifications accompany a genuine DCEC engine from HekoPower?
Every engine ships with an official factory testing certificate, a unique stamped serial number traceable through the global Cummins network, and full compliance documentation for ISO9001 and ISO14001 manufacturing standards.
