Discover the defining engine

Advanced natural gas technology, proven in the field.

HSK78G for well-servicing

HSK78G engine shown in profile with surrounding system components illustrated in the background.
Power without compromise

For too long, operators have had to choose between the proven performance of diesel and the benefits of natural gas. The HSK78G changes that. Combining the latest advancements in natural gas technology with the robust and responsive performance operators know, the transition to new fuel feels like a seamless progression - not a compromise.

Experience the benefits

Lower complexity, more capability

Compact, lightweight and engineered for seamless integration, the HSK78G is built to match existing platform designs. Its unique size, field-ready functionality and fully-flexible system alignment allows fleets to operate the way they always have. With simplified maintenance, reduced part count and durable components, operators can still depend on the reliability and serviceability they need to reduce their engine’s lifecycle operating costs.

Cummins HSK78G engine mounted on a trailer with integrated heavy-duty engine and equipment.

New fuel, familiar feeling

Delivering diesel-like transient performance, the HSK78G's variable-speed capability is engineered to provide the power delivery operators recognize and trust to perform in demanding conditions.

HSK78G engine with visible filtration, piping and engine components.

Engineered to adapt

Moving fleets must continuously adjust to changing conditions, with smarter power, you increase uptime. The HSK78G’s advanced engine controls automatically adapt to changes in fuel composition and operating environments, delivering optimized, reliable performance without the need for manual tuning.

Close-up of electrical and fluid system components on HSK78G engine

The natural gas advantage

Advanced lean-burn natural gas technology enables operators to lower overall fleet emissions, while maintaining the diesel-like performance they expect, with Spark-ignited EPA Mobile Off-Highway compliance.

Close-up of cylinder heads and fuel system components on HSK78G engine

Tried and tested perfomance

10,000 +

Total operation hours.

10,300

ft-lb peak torque output achieved.

Cummins SPP in the news

Read more about the HSK78G’s journey.

Sunrise over a flat desert landscape with distant mountains silhouetted against the horizon

Q1 2026: Validated in the field

Cummins validates its natural gas, variable speed technology for the hydraulic fracturing market through field test operations
Red industrial engine inside a power generation enclosure with access doors open

Q1 2025: Industry first development

Cummins and Liberty Energy partner to develop and deploy industry-first variable speed, large displacement natural gas engine powered hydraulic fracturing system.