Experimental study on performance and emissions of a high speed diesel engine fuelled with n-butanol diesel blends under premixed low temperature combustion

Abstract In the present paper, results of an experimental investigation carried out in a modern diesel engine running at different operative conditions and fuelled with blends of diesel and n-butanol, are reported. The exploration strategy was focused on the management of the timing and injection pressure to achieve a condition in which the whole amount of fuel was delivered before ignition. The aim of the paper was to evaluate the potential to employ fuel blends having low cetane number and high resistance to auto-ignition to reduce engine out emissions of NOx and smoke without significant penalty on engine performance. Fuel blends were mixed by the baseline diesel (BU00) with 20% and 40% of n-butanol by volume. The n-butanol was taken by commercial production that is largely produced through petrochemical pathways although the molecule is substantially unchanged for butanol produced through biological mechanisms. The experimental activity was performed on a turbocharged, water cooled, DI diesel engine, equipped with a common rail injection system. The engine equipment includes an exhaust gas recirculation system controlled by an external driver, a piezo-quartz pressure transducer to detect the in-cylinder pressure signal and a current probe to acquire the energizing current to the injectors. Engine tests were carried out at 2500 rpm and 0.8 MPa of BMEP exploring the effect of start of injection, O2 concentration at intake and injection pressure on combustion behavior and engine out emissions. The in-cylinder pressure and rate of heat release were investigated for the neat diesel and the two blends to evaluate engine performance and exhaust emissions both for the conventional diesel and the advanced premixed combustion processes. The management of injection pressure, O2 concentration at intake and injection timing allowed to realize a partial premixed combustion by extending the ignition delay, particularly for blends. The main results of the investigation made reach smoke and NOx emissions due to the longer ignition delay and a better mixing control before combustion. The joint effect of higher resistance to auto ignition and higher volatility of n-butanol blends improved emissions compared to the neat diesel fuel with a low penalty on fuel consumption.

[1]  Dimitrios T. Hountalas,et al.  Operational and Environmental Evaluation of Diesel Engines Burning Oxygen-Enriched Intake Air or Oxygen-Enriched Fuels: A Review , 2004 .

[2]  Hans-Erik Ångström,et al.  Advantages of Fuels with High Resistance to Auto-ignition in Late-injection, Low-temperature, Compression Ignition Combustion , 2006 .

[3]  Dimitrios C. Kyritsis,et al.  Comparative second-law analysis of internal combustion engine operation for methane, methanol, and dodecane fuels , 2001 .

[4]  Paul C. Miles,et al.  The Influence of Charge Dilution and Injection Timing on Low-Temperature Diesel Combustion and Emissions , 2005 .

[5]  Dimitrios T. Hountalas,et al.  Study of the performance and exhaust emissions of a spark-ignited engine operating on syngas fuel , 2007 .

[6]  Hans-Erik Ångström,et al.  Partially pre-mixed auto-ignition of gasoline to attain low smoke and low NOx at high load in a compression ignition engine and comparison with a diesel fuel , 2007 .

[7]  Shuji Kimura,et al.  New Combustion Concept for Ultra-Clean and High-Efficiency Small DI Diesel Engines , 1999 .

[8]  K. Akihama,et al.  Mechanism of the Smokeless Rich Diesel Combustion by Reducing Temperature , 2001 .

[9]  Shuji Kimura,et al.  Ultra - Clean Combustion Technology Combining a Low - Temperature and Premixed Combustion Concept fo , 2001 .

[10]  Takeyuki Kamimoto,et al.  High Combustion Temperature for the Reduction of Particulate in Diesel Engines , 1988 .

[11]  C. N. Michos,et al.  Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model , 2008 .

[12]  C. D. Rakopoulos,et al.  Investigation of the performance and emissions of bus engine operating on butanol/diesel fuel blends , 2010 .

[13]  Paul C. Miles,et al.  Detailed Unburned Hydrocarbon Investigations in a Highly-Dilute Diesel Low Temperature Combustion Regime , 2009 .

[14]  Gautam Kalghatgi,et al.  Auto-Ignition Quality of Practical Fuels and Implications for Fuel Requirements of Future SI and HCCI Engines , 2005 .

[15]  Rolf D. Reitz,et al.  Operating a Heavy-Duty Direct-Injection Compression-Ignition Engine with Gasoline for Low Emissions , 2009 .

[16]  Zhen Huang,et al.  Premixed low-temperature combustion of blends of diesel and gasoline in a high speed compression ignition engine , 2011 .

[17]  Zunqing Zheng,et al.  Experimental study of n-butanol additive and multi-injection on HD diesel engine performance and emissions , 2010 .

[18]  D. Splitter,et al.  Experiments and Modeling of Dual-Fuel HCCI and PCCI Combustion Using In-Cylinder Fuel Blending , 2009 .

[19]  Rolf D. Reitz,et al.  In-Cylinder Fuel Blending of Gasoline/Diesel for Improved Efficiency and Lowest Possible Emissions on a Multi-Cylinder Light-Duty Diesel Engine , 2010 .

[20]  Zhen Huang,et al.  Attainment and Load Extension of High-Efficiency Premixed Low-Temperature Combustion with Dieseline in a Compression Ignition Engine , 2010 .

[21]  Bengt Johansson,et al.  Low NOx and Low Smoke Operation of a Diesel Engine Using Gasoline-Like Fuels , 2009 .

[22]  C. D. Rakopoulos,et al.  Effects of butanol–diesel fuel blends on the performance and emissions of a high-speed DI diesel engine , 2010 .