1-hexene autoignition control by prior reaction with ozone

Abstract

The autoignition timing of 1-hexene was controlled in a Homogeneous Charge Compression Ignition (HCCI) engine by reacting the fuel with ozone-containing air prior to its combustion. The experiments were conducted in a single cylinder research engine instrumented with a cylinder pressure sensor. The fuel was chemically characterised using Nuclear Magnetic Resonance (NMR) spectroscopy before and after its reaction with ozone. The NMR analyses showed that this preliminary reaction produced several oxygenated products within the fuel, and was likely to have resulted in the formation of ozonide molecules having a peroxidic structure with several oxygen molecules in series. To understand how this would affect the ignition reactions, the ignition process was modelled numerically using a single-zone chemical kinetic reactor model. The modelling suggested that peroxide molecules decomposed during the compression of the reactants in the engine and advanced ignition timing by promoting early decomposition of the fuel through the formation of radicals.

1-Hexene Ozonolysis across Atmospheric and Combustion Temperatures via Synchrotron-Based Photoelectron Spectroscopy and Chemical Ionization Mass Spectrometry

“…O 3 facilitating 1-hexene conversion under typically inhibitory combustion conditions is consistent with the results of Schonborn et al 68 who reported the ignition improvement of an HCCI combustion engine. The influence of O 3 on the NTC has also been recently reported for several O 3 -initiated alkane oxidation systems, 24,25 but temperature investigations for alkenes between 300 and 600 K, enabling the observation of atmospheric/combustion chemistry transitions, were so far limited to ethylene 27,29 and butene.…”

An overview of the effects of fuel molecular structure on the combustion and emissions characteristics of compression ignition engines

“…those that require reduced durations of ignition delay or variable control of the ignition timing. 116,117 Declaration of conflicting interests…”

Enhancing 1-Hexene Reactivity Under Inhibitive Temperatures Using Ozone

“…In the literature, 1-hexene (C 6 H 12 ) is often proposed as a representative alkene component in gasoline surrogate fuels. − However, there is only one study on the reactions of this fuel with O 3 under combustion-relevant conditions. This was performed in a homogeneous charge compression ignition (HCCI) engine by reacting a variable fuel portion with O 3 -containing air by Schönborn et al . These measurements indicate an increase in pressure and heat release in the presence of O 3 , as well as earlier ignition.…”

“…13−15 However, there is only one study on the reactions of this fuel with O 3 under combustion-relevant conditions. This was performed in a homogeneous charge compression ignition (HCCI) engine by reacting a variable fuel portion with O 3 -containing air by Schonborn et al 16 These measurements indicate an increase in pressure and heat release in the presence of O 3 , as well as earlier ignition. There was also a notable decrease in particle emissions and an increase in combustion efficiency under elevated pressure and temperature conditions.…”