Delphi Technologies’ new heavy-duty fuel injector - Smaller nozzle control valve design virtually eliminates leaks at high pressures for heavy-duty vehicles.
DFI21 injectors: Heavy-duty pressure relief

Because small changes can yield big results.

If you’re a heavy-duty diesel engine manufacturer, you’re likely struggling with how to overcome the considerable regulatory challenges you face. It’s a game of trade-offs between fuel delivery, pressure and performance in your attempts to cut carbon dioxide emissions, maintain the lowest possible levels of particulate matter and nitrogen oxide emissions, plus boost fuel economy.

One of the best ways to meet your targets is to increase the pressure at which fuel is injected into the engine. This creates a finer fuel spray, which combusts more efficiently. But, with higher pressures, the likelihood of fuel injector valve leakages increases, which can completely offset any performance gains.

So, what’s the solution? How about an injector that virtually eliminates leaks – even at 3,000 bar pressure? Sound good?

Then meet DFI21.


Smaller really is better.

The DFI21 is the latest heavy-duty diesel engine injector advance from Delphi Technologies. It uses a smaller nozzle control valve to deliver:

  • Multiple injections for optimal combustion performance. Capable of nine injections per cycle, the DFI21 reduces response times, providing improved valve dynamics and control.
  • Very low leakage supplying very high efficiency. The DFI21 allows for 3,000 bar operation with virtually no fuel consumption penalty. And at lower bar pressures, it can result in better fuel efficiency. It also cuts the temperature of back leaks for improved robustness. The very low leakage also results in significantly lower operating temperature in turn reducing the risk of harmful fuel deposits.
  • Overall reduction in injector envelope size. Going smaller on the nozzle control valve translates into reduced injector material content, and reduced packaging space requirements.

multiple injectors

diesel injector


How the DFI21 works.

Let’s step back in time for a moment.

At Delphi Technologies, we’ve always pushed the boundaries in diesel technology. It’s now more than 10 years since we put the world’s first 2,500 bar electronic unit injector, the E3.3, into production for heavy-duty applications. The E3.3 delivered class-leading emissions performance in exactly the same injector envelope as existing unit injectors.

We then developed the F2 family of common rail systems. The F2 family was unique in that it was designed to provide the benefits of common rail systems in flexible packages that could be engineered to fit existing engines – whether the engines were designed for unit injectors, unit pumps, or conventional remote pump fuel systems. The F2 injectors featured 2 millimeter diameter, three-way nozzle control valve technology to deliver low static injector leakage and class-leading dynamic leakage.  But we knew we could do better. Enter the DFI21.

With this new design, we halved the diameter of the nozzle control valve. Not only does this reduce leakage and allow for higher injection pressures, but it creates a smaller package that can be used in high-performance medium- and light-duty diesel applications.

When paired with our closed loop injection control technologies, the DFI21 allows real-time feedback of injection performance to the engine control unit. With this combined package, we can specify the calibration that delivers the best engine performance over the life of the vehicle. More and smaller injection events monitored via the closed-loop system ensure accuracy right to the end of the engine’s design life. And, we’ve designed it in such a way that all of this can be achieved without significant changes to existing engine controllers and, depending on the application, without the need for additional wiring. This saves you time and cost.

commercial vehicle, common rail

Looking ahead.

At Delphi Technologies, we are continuing to develop a range of products for diesel applications. This includes fuel injection systems, after treatment, sensors, engine electronics and software, as well as our class-leading gasoline and alternative fuel technologies.

Want to know more? Contact us today to discover how we can put our advancing diesel engine solutions to work for you.