Getting compressed natural gas car engines closer to market

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To achieve lower toxic emissions and CO2, the car industry is turning to alternative sources to replace traditional diesel and gasoline engines. Compressed natural gas, directly injected into engines by innovative technology, could be one answer.

With funding from LIFE, the Luxembourg-based Delphi Technologies has brought direct injection of compressed natural gas (CNG) closer to market, thanks to a new pre-industrial prototype injector developed within the project LIFE DI-CNG. This prototype enables the direct injection of compressed natural gas into today’s modern car engines, bringing lower emissions with equal performance.

Towards commercialisation 

Injectors are part of engines where compressed fuel is injected into the combustion chambers. Direct injection is a rapidly expanding improvement in engine technology, bringing greater fuel efficiency and greater power to drivetrains. 

The use of compressed natural gas, an alternative fuel mainly composed of methane (CH4), is also on the increase. Compressed natural gas can have a much higher engine compression ratio than gasoline, reducing energy loss and improving fuel efficiency.

But various features hold back faster uptake. CNG is generally used in bivalent engines – engines which can use two types fuel – with conventional port fuel injection systems. These have a lower performance than direct injection systems, so are less attractive to consumers. To meet this gap, the LIFE DI-CNG project developed a reliable, tested alternative which enables direct injection of CNG.

LIFE funding allowed Delphi Technologies to build a pilot production line for its direct injector in Luxembourg. This sped up production of iteratively-tested prototypes, and continues to be used by other partners on EU-funded projects. As Camille Feyder, research and innovation technologist and project lead explained: “The production line serves to build CNG development injectors for consortium partners of the EU-funded Horizon 2020 GASON project, and supports the industrialisation of gasoline and biofuel injectors.”

“Thanks to LIFE funding, we are now in a position to respond quickly to market needs”, Mr Feyder added.

Lifetime improvements

Results from testing various DI-CNG set-ups with three vehicle manufactures, including Ford and Fiat, show equal levels of performance compared to various gasoline direct injection engines, with other results including:

  • a reduction of particulate matter of 90% below the EU 6 regulation limit compared to a CNG port fuel injection engine;
  • a 31% reduction in CO2 compared to a gasoline direct injection engine.

Read the full results in the final report (Google Drive document)

The team focused heavily on other environmental characteristics around both the injector itself and the way in which it is produced, measuring factors such as lifetime durability and methane leak rate. Delphi Technologies enlisted a Life Cycle Assessment research team to analyse the full CO2 impact of producing and running a DI-CNG engine. This found that producing the specific parts for a DI-CNG vehicle generated around 100 mg of CO2-eq/km (CO2 equivalent) more than its gasoline equivalent. But when considering emissions from ‘tank-to-wheel’ and ‘well-to-tank’, the study estimated that monovalent DI-CHG vehicles can reduce CO2-eq emissions by 30%: and by more than 40% when bio-methane is used.

Industry uptake

While the technology has been demonstrated to have strong environmental benefits, uptake depends on other factors like Europe’s fuelling infrastructure.
Pushing growth of the technology is the next step, according to Mr Feyder. “We know that the DI-CNG technology when used in passenger and light duty vehicles has a lower negative impact for people and nature. The automotive industry is aware of these facts, so we are now working with vehicle manufacturers on raising awareness.”

The DI-CNG injector will be presented at the September 2019 International Car fair (IAA) in Frankfurt, following a similar presentation in Las Vegas in January this year.

Image: Pixabay

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