#weekendusers Optimizing fuel injectors in cars for a cleaner future


Gasoline fuel injectors play a crucial role in the combustion process by mixing fuel and air and reducing the productionn of toxic gases in the air. A team of scientists from the Karlsruhe Institute of Technology and the University of Erlangen have been studying injectors in operando this weekend on ID19.

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Modern turbo-charged petrol combustion engines must conform to reduced fuel consumption and particle emissions. The injector design is therefore of highest importance in order to evenly mix fuel and air before the ignition process. This reduces the production of soot or toxic gases released into the environment.

The experiment reproduces the mechanism of injection of fuel in the car in a specially-designed chamber that the scientists at the University of Erlangen designed and fabricated. The goal is to track how the spray distributes itself in the chamber. Of particular interest is the zone from the nozzle to around 10 mm distance, where the spray speed reaches 100 metres per second.

“We have done some experiments using laser-optical methods, but we find that there is excessive scattering and we are unable to see what happens in the interior of the spray”, explains Richard Welss, scientist at the University of Erlangen. “On the other hand, synchrotron high-speed radiography is able to freeze the motion due to short bunch lengths and the reduced interaction allows us to penetrate the spray close to the nozzle”, he concludes.


Pictures recorded with the ESRF (right) and with an optical method (shadowgraphy). Credits: R. Welss.

Lukas Helfen, also part of the team, from KIT, explains that “ID19 provides outstanding photon flux density, high energy and sensitivity using propagation-based phase contrast, so we are hoping for great data”.

The outcome of this research may help the automobile industry in designing efficient nozzles in combination with highly optimised injection parameters for future engines. The researchers believe that it could reduce particle emissions of direct-injection petrol engines by half, so “all the sleepless nights are definitely worth it if we can contribute to this”.

Text by Montserrat Capellas Espuny


Top image: Richard Welss and Lukas Helfen setting up the experiment. Credits: C. Argoud/ ESRF.