Experimental Studies on Using Butanol and Octanol Isomers as Drop-in Fuels for Diesel Engines
Doktorsavhandling, 2019

The increasing importance of transportation in modern societies has caused fossil fuel consumption to increase greatly in recent decades. However, burning fossil fuels in internal combustion engines can lead to high emissions of greenhouse gases, which cause climate change. Because of this, there is great interest in using alcohols and other renewable fuels in Diesel engines to reduce vehicles’ lifecycle greenhouse gas emissions. It is therefore important to investigate the possibility of using alcohol/Diesel blends, or even fossil-free blends, in both existing Diesel engines and new engines employing advanced combustion concepts.

This thesis explores the use of four alcohols (n-butanol, isobutanol, 2-ethylhexanol, and n-octanol) and two bio-Diesels (hydrotreated vegetable oil, or HVO, and rapeseed methyl ester) as drop-in fuels in Diesel engines. Their effects on the performance and emissions of compression ignition engines were assessed by performing experiments using light- and heavy-duty single cylinder engines under steady-state conditions.

To test the compatibility of alcohol-containing blends with existing engines, HVO and the commercial cetane number (CN) improver DTBP were used to compensate for the alcohols’ low CN values and prepare oxygenated blends with CN values similar to fossil Diesel. Blends with and without fossil Diesel were tested. Two single-cylinder engines were operated at four standard load points using production calibrated engine settings. Experiments were also performed using an advanced combustion strategy (partially premixed combustion) in which the alcohols were blended with fossil Diesel fuel directly to produce mixtures with low cetane numbers (26 or 36). The blends’ effects on spray penetration, flame development, and soot characteristics were investigated in the constant volume combustion chamber.

The results show that from a combustion point of view, the tested alcohol blends with Diesel-like CN values can be used in unmodified existing Diesel engines. Compared to conventional Diesel fuel, the oxygenated blends yielded slightly higher indicated thermal efficiencies, significantly lower soot emissions, and similar heat release profiles. Moreover, partially premixed combustion was shown to further increase thermal efficiency while reducing soot and NOx emissions.

HA2, Hörsalsvägen 4, Gothenburg
Opponent: Professor Martti Larmi, Aalto University, Finland


Tankai Zhang

Chalmers, Mekanik och maritima vetenskaper, Förbränning och framdrivningssystem

V. T. Zhang, J. Eismark, K. Munch, and I. Denbratt, “Effects of a Wave-Shaped Piston Bowl Geometry on the Performance of Heavy Duty Diesel Engines Fueled with Alcohols and Biodiesel Blends,” manuscript submitted to journal in February 2019.

An Experimental Study on the Use of Butanol or Octanol Blends in a Heavy Duty Diesel Engine

SAE International Journal of Fuels and Lubricants,; Vol. 8(2015)p. 610-621

Artikel i vetenskaplig tidskrift

The internal combustion engine’s rapid adoption over the last century has enabled great economic development. However, this has been accompanied by a very pronounced increase in the emissions of greenhouse gases generated by burning fossil fuels, causing global climate change. Concerns about climate change and emissions of pollutants such as particulate matter and nitrogen oxides have prompted calls to greatly reduce or even ban the use of vehicles with internal combustion engines in certain places. However, there is a smart way to reduce greenhouse gas emissions without abandoning the vast number of already-existing internal combustion engine vehicles: using renewable fuels.

The goal of the thesis is to analyse the effects of using renewable fuels (namely butanol, octanol isomers and "bio-Diesel") as drop-in fuels for Diesel engines. The work presented is divided into two related projects. The first investigates the possibility of using blends of renewable fuels with fossil Diesel, and fossil-free blends, in existing Diesel engines. The second examines the performance of the renewable fuel blends when used with a new combustion strategy for advanced engines - partially premixed combustion.

The tested renewable fuels yielded slight increases in engine thermal efficiency while significantly reducing soot emissions in engines with production settings. The use of partially premixed combustion with renewable blends yielded further improvements in thermal efficiency while reducing both soot and nitrogen oxides emissions. These findings show that by combining renewable fuels with innovative technical solutions, the internal combustion engine can contribute to the development of sustainable transport and play an important role in the societies of the future.

Butanol som bränsle för Dieselmotorer

Energimyndigheten (P37176-1), 2013-09-01 -- 2016-09-01.

Butanol som bränsle för Dieselmotorer 2

Energimyndigheten (37176-3), 2017-05-15 -- 2018-12-31.


Annan maskinteknik


Annan kemiteknik





Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4561



HA2, Hörsalsvägen 4, Gothenburg

Opponent: Professor Martti Larmi, Aalto University, Finland

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