Investigation of Mixture Formation and Flammability of Natural Gas and Diesel under Dual Fuel Operating Conditions in the Limits of Flame-quenching and Knocking

Peter A, Rieß S, Wensing M, Frühhaber J, Lauer T (2017)

Publication Language: English

Publication Type: Conference contribution, Conference Contribution

Publication year: 2017

Event location: Okayama Convention Center JP

Abstract

Dual Fuel engines combine both the efficiency and torque characteristics of diesel engines and the reduced emissions of gas engines. Combustion of natural gas is free of particulate matter (PM) and produces less CO2 than petrol fuel. Combined with the application of modern heavy diesel engines, the dual fuel combustion process faces latest exhaust gas legislations. The substitution of air with natural gas leads to a density change of the ambient gas which influences the propagation of direct-injected fuel sprays. In this work, first we investigate this influence on mixture formation with schlieren measurements in a high-pressure high-temperature combustion vessel. In a density range from 11 kg/m³ to 29 kg/m³ and with an injection pressure variation between 80-160 MPa, the air-entrainment is investigated using total momentum conservation. Few millimeters upstream the injector orifice significant amounts of environmental gas are already entrained. Second, the influence of the reduced oxygen content and the presence of natural gas on ignition and combustion is analyzed in an optically accessible rapid compression machine in matters of an injection pressure variation. Homogenous, lean premixed natural gas-air charge is introduced in the combustion chamber and is inflamed by a diesel injection. Between the limits of early flame-quenching and the irregular self-ignition of the natural gas (knocking) the gas-air-diesel composition is varied at same total energy level. The measurements encompass the determination of the combustion behavior via cylinder pressure signal and via high-speed chemoluminescence imaging of the OH-radical and natural luminosity of the flame, respectively. This study shows, the ignition timing remains unaffected at increasing injection pressure. The ignition delay is general increased by natural gas-air atmosphere. A higher injection pressure means that more fuel penetrates faster into the combustion chamber which leads to faster energy release but not too often correlated better mixture formation.

Authors with CRIS profile

Andreas Peter Professur für Fluidsystemtechnik Sebastian Rieß Professur für Fluidsystemtechnik Michael Wensing Professur für Fluidsystemtechnik

Related research project(s)

DualFlame – Modelling and optimisation of the diesel/gas combustion process (DualFlame) DualFlame – Modellierung und Optimierung des Diesel/Gas-Brennverfahrens July 1, 2015 - June 30, 2018

Involved external institutions

Technische Universität Wien / Vienna University of Technology AT Austria (AT)

How to cite

APA:

Peter, A., Rieß, S., Wensing, M., Frühhaber, J., & Lauer, T. (2017). Investigation of Mixture Formation and Flammability of Natural Gas and Diesel under Dual Fuel Operating Conditions in the Limits of Flame-quenching and Knocking. In Proceedings of the The 9th International Conference on Modelling and Diagnostics for Advanced Engine Systems. Okayama Convention Center, JP.

MLA:

Peter, Andreas, et al. "Investigation of Mixture Formation and Flammability of Natural Gas and Diesel under Dual Fuel Operating Conditions in the Limits of Flame-quenching and Knocking." Proceedings of the The 9th International Conference on Modelling and Diagnostics for Advanced Engine Systems, Okayama Convention Center 2017.

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