Performance and Emissions of a Turbocharged Spark Ignition Engine Fuelled with CNG and CNG/Hydrogen Blends Politecnico di Torino

Format:

Conference/Event

Author/Creator:

Baratta, Baratta, author.

Contributor:

D'Ambrosio, Stefano

Misul, Daniela (Mechanical engineer)

Conference Name:

SAE 2013 World Congress & Exhibition (2013-04-16 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2013

Summary:

An experimental investigation was performed on a turbochargedspark-ignition 4-cylinder production engine fuelled with naturalgas and with two blends of natural gas and hydrogen (15% and 25% involume of H₂). The engine was purposely designed to give optimalperformance when running on CNG. The first part of the experimentalcampaign was carried out at MBT timing under stoichiometricconditions: load sweeps at constant engine speed and speed sweepsat constant load were performed. Afterwards, spark advance sweepsand relative air/fuel ratio sweeps were acquired at constant enginespeed and load. The three fuels were compared in terms ofperformance (fuel conversion efficiency, brake specific fuelconsumption, brake specific energy consumption and indicated meaneffective pressure) and brake specific emissions (THC,NOx, CO). The pressure trace was acquired in the fourcylinders to perform a cycle-by-cycle and cylinder-by-cylinderanalysis of the peak firing pressure and the indicated meaneffective pressure as well as of the main combustionparameters.As far as MBT timing stoichiometric operations are concerned,the addition of hydrogen determines a reduction in the sparkadvance. The higher energy content of hydrogen with respect tomethane determines lower brake specific fuel consumption values.Conversely, similar values were found for the brake specific energyconsumption, which is intimately related to the fuel conversionefficiency. The addition of H₂ produces an appreciable reduction inTHC which overcomes the mere reduction of HC in the blend. A smallimprovement can also be found for CO emissions whereasNOx turned out to be slightly affected by the H₂ contentin the fuel.The air/fuel ratio in the relative air/fuel ratio sweeps wasvaried in the rich and lean field up to the lean operation limit.The addition of hydrogen determined a marked reduction of thecoefficient of variations in the lean field, thus allowing anextension of the lean operation limit with respect to CNGoperation. The addition of hydrogen still determined a considerableTHC reduction which turned out to be even more evident as one movedto the lean field.Regardless of the considered fuel, a significantcylinder-to-cylinder variation emerged, mainly to be attributed tothe cylinder spatial distribution, which in turn affects theeffectiveness of the cooling system and the uniform air/fuelmixture distribution

Notes:

Vendor supplied data

Publisher Number:

2013-01-0866

Access Restriction:

Restricted for use by site license