ISL G for Euro Truck & Bus


ISL G for Euro Truck & BusThe ISL G is the natural choice in alternative-fuel engine technology. With industry leading performance, it combines all the advantages of clean burning, low cost natural gas with “no compromises” in power and torque. It moves to Euro 6 emissions with minimal changes from Euro 5, making it ideal for alternative fuel bus and truck applications.

The ISL G engine block is shared with the Cummins ISL diesel – a full skirted block for increased rigidity and strength. The design provides superior piston ring and bearing life, improved coolant flow and targeted piston cooling, for greater reliability and superior durability. The engine’s life to rebuild and rebuildability are similar to those of diesel engines. The 8.9 litre ISL G uses advanced stoichiometric combustion with cooled Exhaust Gas Recirculation (EGR) to meet ultra-low emissions requirements. The cooled-EGR system takes a measured quantity of exhaust gas and passes it through a cooler to reduce temperatures before mixing it with fuel and the incoming air charge to the cylinder. This lowers combustion temperatures and knock tendency, reducing engine out emissions and noise. With a pedigree of over 1 million engines to date, Cummins cooled EGR technology is proven in a wide range of installations.

Stoichiometric combustion is the ideal combustion process where all fuel and oxygen is completely consumed. This means that no unburned fuel or oxygen exits through the exhaust. Combined with cooled EGR it improves power density and fuel economy to create a high performance natural gas engine. It also enables the use of simpler, lower cost exhaust aftertreatment systems. Since its introduction for EPA 2010 and Euro 5 emissions, thousands of truck and bus customers have noticed the impressive low-end torque, transient response and quiet operation of the ISL G. Compared with previous Cummins lean-burn natural gas engines, ISL G torque at idle is improved over 30 percent, and fuel economy is improved by up to 5 percent.

For Euro 6, all of the benefits designed for Euro 5 are carried over, with minimal engine changes required.

Engine Finder Specifications

Natural Gas
Certification Level EPA 2010
Euro 6
Euro 5
Power 247 - 316 hp / 184 - 236 kW
Torque 730 - 1000 lb-ft / 990 - 1356 N•m


Power Range PS (kW) 

Rated Speed (rpm) 

Peak Torque Nm (lb-ft) 

250-320 (184-235) 


990-1356 (730-1000)


• Factory-Built, Dedicated Natural Gas Engine – manufactured by Cummins on the same assembly line as Cummins diesels, the ISL G shares many components and parts with Cummins L Series diesels, inheriting their renowned simplicity.
• Heavy-Duty Design – rugged features include replaceable wet liners, roller followers, by-pass oil filtration and targeted piston cooling for longer service in the toughest work environments.
• Fuel Capability – the ISL G is capable of operating on compressed or liquefied natural gas (CNG, LNG). The ISL G can also operate on up to 100 percent biomethane, renewable natural gas made from biogas or landfill gas that has been upgraded to pipeline and vehicle fuel quality.
• Air/Fuel Regulation – Cummins closed-loop electronic control system based on Cummins Interact™ System. Sensors for engine parameters, including intake manifold pressure and temperature, fuel inlet pressure, knock detection, air/fuel ratio and fuel mass flow.
• High Power and Torque – available up to 320ps with 1356 Nm of torque for alternative fuel truck and bus applications.
• Closed crankcase ventilation (CCV) – new remote mounted system required to re-cycle blow-by gases now counted in the engine emissions.
• Cummins Wastegated Turbocharger – developed by Cummins Turbo Technologies with electronic control for precise air handling. Has a water-cooled bearing housing for durability.
• Air Intake System – charge air cooling reduces emissions by lowering intake manifold air temperatures.
• Maintenance-Free Aftertreatment – uses a Three-Way Catalyst (3WC) aftertreatment. 3WCs are effective, simple, passive devices, packaged as part of the muffler, that provide consistent emissions control performance and are maintenance-free. The ISL G does not require active aftertreatment such as a Diesel Particulate Filter (DPF) or Selective Catalytic Reduction (SCR).
• High-Energy Ignition System – spark ignited system providing better performance and longer service intervals with improved spark-plug and coil durability.
• High-Efficiency Lube Cooler – lowers oil temperatures for longer engine life.
• Accessory Belt Drive System – self-tensioning serpentine polyvee belt accessory drive system for water pump, engine-mounted fan hub and most alternators. Gear-driven air compressor with provision for gear-driven hydraulic pump.
• Crankshaft – eight counterweight, fully balanced, hightensile- strength steel forging with induction hardened fillets and journals, for outstanding durability.
• Control System – full drive-by-wire. Electronic Control Module (ECM) provides full monitoring and control of the engine sensors, fuel system and ignition system. Full interface capability to Cummins INSITE and diagnostic service tools.
 Oil Filter – the combination full-flow and bypass oil filter improves filtration while minimizing oil filter replacement and disposal costs.
• Global Support – backed by the widest network in the industry, with over 5,000 service outlets worldwide.
• Contact your local customer assistance centre for technical support, details on






Oil & Filter 




Fuel Filter 




Overhead Adjustment 




  • Euro 6 details to be added at a later date
  • All numbers are adjustable based on duty cycle. 
  • For complete maintenance information, please consult your Owner's Manual or Operations and Maintenance Manual.

Brochures Available

Title Bulletin Number Request View  
Cummins Natural Gas Parts Brochure 2878880 Request View  Download
ISL G Euro 6 Engine Brochure - A4 Format 4971387 View  Download