Overview#
The Cummins QSX15-G9 is a 500 kW standby / 450 kW prime diesel generator set built on Cummins' 15-liter inline-6 platform. The QSX15 was a landmark engine in the power generation industry -- the first heavy-duty diesel to feature 24-valve dual overhead camshaft (DOHC) technology, delivering more power from fewer parts while eliminating external fluid lines that are common failure points on traditional engines.
The G9 designation indicates the G-Drive variant optimized for generator set applications at 60 Hz (1800 rpm), with the Coolpac integrated cooling package and air cleaner kit included as a complete power package.
Engine technology#
Key engineering features of the QSX15 platform:
- 24-valve DOHC: Four valves per cylinder for increased airflow, faster response, and more complete combustion
- Holset HX82 turbocharger: Wastegated design optimizes boost across the torque curve with improved transient response
- Integrated block design: All fluid circuits are cast into the block, eliminating external hoses and reducing potential leak points by 30% versus comparable engines
- High-pressure fuel injection: Capable of over 1,900 bar (28,000 psi) for cleaner, more fuel-efficient combustion via direct injection
- Coolpac integrated design: Factory-matched cooling package and air cleaner, specifically developed and tested for G-Drive applications
Fuel consumption#
At 1800 rpm (60 Hz), the QSX15-G9 delivers competitive fuel efficiency:
| Rating | Load | kWm | L/hr | g/kWh |
|---|---|---|---|---|
| Standby | 100% | 563 | 135.9 | 35.9 |
| Prime | 100% | 507 | 117.8 | 31.1 |
| Prime | 75% | 380 | 90.5 | 23.9 |
| Prime | 50% | 254 | 65.3 | 17.2 |
| Continuous | 100% | 354 | 85.3 | 22.5 |
Physical specifications#
The Coolpac integrated package keeps the QSX15-G9 compact for a 500 kW class unit: 2269 mm long by 1332 mm wide by 1669 mm high, with a dry weight of 1658 kg. The limiting ambient temperature for the standard cooling system is 55C, providing excellent hot-climate capability.
Our service experience#
The QSX15 is one of Cummins' most service-friendly platforms. The DOHC design with integrated fluid circuits means fewer external connections to inspect and fewer hose replacements. The spin-on fuel filters with water separator and spin-on full flow lube oil filter simplify routine maintenance. The 91-liter oil capacity provides a generous oil change interval. Cummins' worldwide distributor network ensures parts availability for critical standby applications.
FAQ#
What is the standby rating of the Cummins QSX15?#
The Cummins QSX15-G9 is rated at 500 kW standby / 625 kVA at 0.8 power factor, 60 Hz, 1800 rpm. Prime rating is 450 kW / 563 kVA. Continuous rating is 303 kW / 379 kVA.
What engine does the Cummins QSX15 use?#
The QSX15 uses the Cummins QSX15-G9 — a 15.0-liter, inline-6-cylinder, turbocharged and aftercooled diesel with 24-valve dual overhead camshaft (DOHC) technology and a Holset HX82 wastegated turbocharger. The integrated block design eliminates external hoses for the lube, coolant, and fuel circuits. It is EPA NSPS certified.
What are the service intervals for the Cummins QSX15?#
Oil and filter changes are due at 500 hours or 12 months. Fuel filter replacement is scheduled at 500-hour intervals. Air filter replacement is due at 1,000-hour intervals. Annual load bank testing is recommended. Major overhaul interval is 30,000 hours under standard standby duty conditions.
Is the Cummins QSX15 EPA compliant?#
Yes. The QSX15-G9 is EPA NSPS certified for stationary power generation. No aftertreatment (DPF/SCR) is required, keeping the maintenance profile straightforward.
Can the Cummins QSX15 be paralleled?#
Yes. The QSX15 with PowerCommand paralleling controls supports genset-to-genset isochronous load sharing. It is used in multi-unit paralleling arrays for 1–2 MW facilities. Consult a Cummins distributor for specific control configurations.
What fuel type does the Cummins QSX15 use?#
The QSX15-G9 runs on diesel fuel. Ultra-low sulphur diesel (ULSD) is compatible. The integrated fuel system design with spin-on filters and water separator provides good protection for the high-pressure fuel injection components.
What is the warranty on the Cummins QSX15?#
Standard Cummins warranty for new generator sets is 2 years or 2,000 hours for standby applications. Extended warranty options are available through Cummins authorized dealers.
