Browse Publications Technical Papers 2011-01-1995

Potential of Concomitant Injection of CNG and Gasoline on a 1.6L Gasoline Direct Injection Turbocharged Engine 2011-01-1995

The use of CNG in modern spark ignition turbocharged engine offers many advantages such as high knocking resistance, low CO₂ emissions and high specific power outputs. On the other hand, compared to gasoline, the volumetric efficiency is significantly decreased when CNG is port-injected due to its low energy density. In order to address this issue, recent studies have successfully highlighted the advantages on port-injection engines of the CIGAL™ concept (Concomitant Injection of Gas And Liquid fuels) from IFP Energies Nouvelles.
However, the combination of port-injection of CNG with direct injection of gasoline remains unexplored. This paper investigates this novel injection concept on the four-cylinder 1.6L turbocharged GDI engine with inlet variable valve timing resulting from the cooperation between PSA Peugeot-Citroen and the BMW Group. This engine was fitted with an independent CNG port-injection system and a specific engine management system was implemented in order to allow concomitant injection operation.
The first part of the study investigates the potential of concomitant injection compared to gasoline and methane operation. On the stock configuration, 29 bar BMEP (370 N.m) were reached at 2500 rpm with 30% gasoline and 70% methane in stoichiometric conditions. Also, significant reductions of fuel consumption and HC emissions were observed. Full load tests carried out with a smaller turbocharger enhanced the synergy effect between the two fuels at lower speeds.
The second part of this work focuses on the reliability of the gasoline direct injectors during CNG operation. Temperature measurements on the gasoline injector nozzles were carried out in gasoline, CNG and concomitant injection modes. Finally, the results of gasoline direct injectors durability tests under CNG and gasoline operation are discussed.


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