Optical Diagnostics of Spray Characteristics and Soot Volume Fractions of n-Butanol, n-Octanol, Diesel, and Hydrotreated Vegetable Oil Blends in a Constant Volume Combustion Chamber
Journal article, 2019

The effects of using n-butanol, n-octanol, fossil Diesel, hydrotreated vegetable oil (HVO), and blends of these fuels on spray penetration, flame and soot characteristics were investigated in a high-pressure high-temperature constant volume combustion chamber designed to mimic a heavy duty Diesel engine. Backlight illumination was used to capture liquid and vapor phase spray images with a high-speed camera. The flame lift-off length (LOL) and ignition delay were determined by analyzing OH* chemiluminescence images. Laser extinction diagnostics were used to measure the spatially and temporally resolved soot volume fraction. The spray experiments were performed by injecting fuels under non-combusting (623 K) and combusting (823 K) conditions at a fixed ambient air density of 26 kg/m3. A Scania 0.19 mm single straight hole injector and Scania XPI common rail fuel supply system were used to produce injection pressures of 120 MPa and 180 MPa. To evaluate the effect of cetane number (CN) variation on combustion processes and soot emissions, di-tertiary-butyl peroxide (DTBP) was added to one blend to modify its CN without greatly altering its composition. The different fuels exhibited similar vapor phase penetration, but their liquid phase penetration varied significantly with the fuels’ physical properties. HVO exhibited the longest steady state liquid penetration. A fuel has a longer ignition delay, resulting in a longer flame lift-off length and thus a lower soot optical thickness and soot volume fraction distribution. Compared to Diesel fuel, n-butanol blends and n-octanol produced much lower soot emissions because of their oxygen content, lower stoichiometric A/F ratio, and high latent heat of vaporization.

Author

Tankai Zhang

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Mats Andersson

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Karin Munch

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Ingemar Denbratt

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

SAE Technical Papers

01487191 (ISSN) 26883627 (eISSN)

Vol. 2019-January January Technical Paper 2019-01-0019

Butanol as fuel for Diesel engines 2

Swedish Energy Agency (37176-3), 2017-05-15 -- 2018-12-31.

Subject Categories

Mechanical Engineering

Energy Engineering

Bioenergy

Areas of Advance

Transport

DOI

10.4271/2019-01-0019

More information

Latest update

6/8/2022 2