Because with GDi high-pressure fuel pumps, the quieter the better.
When debating the merits of gasoline direct injection engines, conversations can jump from better gas mileage, lower emissions, and ZEV bridge technology to higher costs, increased complexity and troublesome particulate problems. But the biggest noise about GDi engines is most likely ... well ... about their noise.
The constant, rapid fire, extremely noticeable, "tickticktickticktickticktickticktickticktick" emanating from the engine's high-pressure fuel pump. It's a clamor loud enough to drown out the benefits of the technology with first, vehicles owners, who misinterpret the sound as a sign of something wrong; and second, with you, the vehicle manufacturer, who must quiet customer complaints and frustrations brought on by unnecessary service visits.
Taking the noise down a notch is possible when you engage Delphi Technologies. That's because our Gen II Gasoline Fuel Pump (GFP2) delivers industry-leading low decibel levels. Better, the GFP2 is designed to perform - and last - at leading-edge 350 bar pressures.
This creates a GDi soultion that will let you pump up the volume in all the right places.
Fighting pressure with pressure.
Before we dive into the GFP2, let's first talk a bit about GDi. These advanced propulsion systems inject fuel directly into the combustion chamber at high pressures. Going direct allows better performance from today's smaller, turbocharged engines, delivering improved fuel economy and lower CO2 emissions without sacrificing the performance.
However, GDi does have its drawbacks. The systems are generally more complex to engineer, manufacture and maintain. Component durability is essential given the high pressures and extreme heat. The fuel pump "tick" is also a byproduct of the punishing pressures. And then there's the increase in particulate emissions - both in mass (PM) and number (PN) - due to shorter, direct-to-combustion air/fuel mixing time. This can produce soot particles in the chamber that get vented into the air, especially with cold starts.
Given the complications high pressures create, it seems almost contradictory that the solution to these obstacles is to push pressures even further. But that's exactly what we did.
At Delphi Technologies, we turned up the pressure, from the industry norm of 200 bar to 350 bar. This more than 50 percent increase in fuel pressure enabled us to reduce fuel droplet size and boost injection speeds. Smaller droplets shot faster into combustion chamber enhances evaporation. And, better evap equals fewer PM/PN.
In fact, our 350 bar GDI system generates 70 percent fewer exhaust particulates than current systems, allowing you to hit both Euro 6d and China 6 emissions standards with a single solution with simpler aftertreatment systems.
And the development of the GFP2 was a lynchpin in our ability to set this new bar for GDi performance.
In designing the GFP2, our engineers used our Gen I Gasoline Fuel Pump as the base. This workhorse pump is recognized as best-in-class for durability, performance and exterior noise. We were determined to sustain excellence on these fronts with the GFP2.
Not an easy task when you consider the role the fuel pump plays in GDi. In addition to increasing fuel pressure, the pump's primary function is to regulate fuel flow and supply, as well as protect the entire fuel system from pressure dips and spikes. The more pressure you add, the greater the risk for the system to be fuel starved or flooded. Higher pressures also put more stress on internal pump elements such as the plunger, spill valve and O-rings. This can lead to failures. Finally, amp the pressure and you amp the pump's noise as it's forced to work harder and faster.
So, with the GFP2, we had to deliver better durability and steady performance, under higher pressures without increasing the noise levels. We also had to watch costs, complexity and weight so as not to compromise scalability, flexibility and fuel economy.
The GFP2 features:
- Specially developed seals at the plunger/bearing interface designed to minimize internal fuel loss. This boosts pressure at very low RPMs, delivering faster engine starts, as well as up to 40 percent overall better efficiency then competitors' pumps.
- Fewer welds and stronger materials in pressure- and load-bearing elements, including the spill valve, which improves overall durability.
- Stronger, stiffer overall body design that better withstands vibration and absorbs sound.
- Fewer or eliminated internal elements, such as O-rings on the damper cup assembly, which cuts costs, enhances performance and reduces the potential for evaporative emission leaks.
- Upgrades to packaging, including a 360-degree flange and a 180-degree electrical connector, which allows the GFP2 to fit virtually any GDi engine design.
- Improvements to the fuel inlet, internal damper assembly, mounting flange and outlet fitting to further reduce noise levels.
At the end of the 18-month development cycle, our engineers created a new, high pressure fuel pump that was stronger, sleeker, simpler, which also tamed the "tick".
In fact, the GFP2 achieves industry-leading low noise levels when used in conjunction with Delphi Technologies' low-noise electrical drive control strategy.
Another key feature: The GFP2 can be adapted for use with any GDi system. Delphi Technologies is among the few suppliers to offer a large range of plunger sizes, along with customized cam designs, which can be matched to the profile of any GDi engine. This means you can quickly and easily integrate the GFP2 into your existing GDi platforms with minimal downtime.
The latest estimates from several research firms project the global GDi market will grow in excess of 10 percent annually through 2026. As such, we plan to help fuel that demand through ongoing pressure and fuel pump advancements. This includes a few GFP3 (Gen 3) pump, which will be capable of operating continuously at 500-plus bar and a new plunger seal component to eliminate leak paths to increase efficiencies, particularly with cold engine starts and higher pressure systems. Contact us today to discover what we have in store and how we can help you on your path to GDi success.