Simplifying engine design with fuel-lubricated pumps

As the commercial vehicle industry moves toward more efficient, reliable, and flexible systems, Cummins is advancing fuel system design with the fuel-lubricated pump (FLP). This compact and modular solution is built for both on-highway and off-highway applications, reducing system complexity while maintaining high performance across a wide range of engine platforms and fuel types.

What is a fuel-lubricated pump?

A fuel-lubricated pump is a type of high-pressure fuel pump that uses the fuel itself as a lubricant for internal moving parts. This eliminates the need for oil-based lubrication circuits commonly found in traditional pumps, simplifying engine architecture and reducing the total number of components.

Cummins has designed this system to be available on the new engine platforms and adaptable for other OEM engines. Its integrated architecture supports evolving powertrain demands and aligns with Cummins’ commitment to reliability, ease of maintenance, and performance optimization across a broad range of applications.

What are the benefits of fuel-lubricated pumps?

The FLP offers a variety of performance, design, and cost benefits that make it a compelling solution for both OEMs and end users.

Lower total cost of ownership

The FLP simplifies the engine system by eliminating separate oil lubrication passages. With fewer parts and easier routing, it reduces assembly and service time, lowering both manufacturing and maintenance costs.  Its compact design and high drive speed also make the pump more affordable than traditional oil-lubricated designs.

Compact size for seamless integration

Compared to older pump technologies, the FLP has a smaller package size, making it easier for the customer to integrate. This compact footprint offers increased design flexibility and supports modern vehicle packaging needs, especially as OEMs prioritize weight and space savings.

Built for diverse applications

One of the most powerful advantages of Cummins’ FLP technology is its modular design. The platform is engineered for easy tailoring across various engine sizes and duty cycles. Whether supporting midrange or heavy-duty engines, the FLP enables efficient fuel delivery without compromising durability.

This modularity ensures that Cummins and its partners can create tailored, application-specific solutions with faster design cycles and fewer platform limitations.

Improved engine efficiency and performance

Fuel-lubricated pumps improve engine efficiency by streamlining fuel delivery and reducing parasitic load. Without fuel and oil transfer, it helps lower emissions, improve combustion and extend oil intervals.  

Active Inlet Metering & Inlet Metering Valve

Fuel delivery to the high-pressure system is managed by either Active Inlet Metering (AIM) or an Inlet Metering Valve (IMV), each offering different benefits:

• AIM uses a unique valve for each pumping chamber, allowing for more precise fuel delivery and rail pressure control. It’s ideal for performance-focused setups 
• IMV relies on a single valve for the whole pump. It’s a simpler and lower-cost solution, though it doesn’t’ offer the same level of pressure control precision as AIM. 

Lower noise, vibration and harshness

The pump’s design and integration into the powertrain help minimize noise, vibration, and harshness for better driver experience.  

Compatibility with different fuel qualities

Fuel quality can vary significantly across regions and applications—from ultra-low sulfur diesel to higher biodiesel blends and fuels with lower lubricity. These variations create unique challenges, especially during long-term storage, due to biodiesel’s tendency to absorb water and the importance of maintaining fuel cleanliness.  To ensure durability and consistent performance across a wide range of fuel types, the FLP is engineered with robust materials and precise tolerances.  Furthermore, Cummins Fuel Systems provides clear guidelines on selecting the appropriate filtration package and maintaining fuel cleanliness to mitigate the effects of alternate fuels.

This means fleets operating in remote regions or emerging markets can confidently use the FLP without concern over premature wear or fuel incompatibility. Its design ensures consistent performance across fuel qualities, enabling greater operating flexibility and geographic reach.

Fuel-lubricated pumps in the off-highway market

While the FLP offers clear benefits for on-highway vehicles, its rugged design also makes it an ideal fit for off-highway applications. Equipment used in construction, mining, and agriculture often operates in challenging environments with heavy loads, rough terrain, and variable fuel conditions.

The FLP’s simplified design, resistance to wear, and ability to handle multiple fuel types make it particularly valuable in off-highway sectors where downtime is costly and operating conditions are less predictable.

Whether integrated into a wheel loader, harvester, or off-road truck, the FLP supports maximum uptime, operational efficiency, and long-term durability—all critical factors for operators working in extreme conditions.