High efficiency ethanol–diesel dual-fuel combustion: Analyses of performance, emissions and thermal efficiency over the engine load range

Because of the potential to reduce NOx and PM emissions simultaneously and the utilization of biofuel, diesel/compressed natural gas (CNG) dual-fuel combustion mode with port injection of CNG and direct injection of diesel has been widely studied. While in comparison with conventional diesel combustion mode, the dual-fuel combustion mode generally leads lower thermal efficiency, especially at low and medium load, and higher carbon monoxide (CO) and total hydrocarbons (THC) emissions. In this work, n-butanol was blended with diesel as the pilot fuel to explore the possibility to improve the performance and emissions of dual-fuel combustion mode with CNG. Various pilot fuels of B0 (pure diesel), B10 (90% diesel/10% n-butanol by volume basis), B20 (80% diesel/20% n-butanol) and B30 (70% diesel/30% n-butanol) were compared at the CNG substitution rate of 70% by energy basis under the engine speeds of 1400 and 1800 rpm. The experiments were carried out by sweeping a wide range of pilot fuel start of injection timings based on the same total input energy including pilot fuel and CNG. As n-butanol was added into the pilot fuel, the pilot fuel/CNG/air mixture tends to be more homogeneous. The results showed that for the engine speed of 1400 rpm, pilot fuel with n-butanol addition leads to a slightly lower indicated thermal efficiency (ITE). B30 reveals much lower NOx emission and slightly higher THC emissions. For the engine speed of 1800 rpm, B20 can improve ITE and decrease the NOx and THC emissions simultaneously relative to B0.

Download Full-text

Combustion and Emission Characteristics of a CI Engine Operating in Diesel-1-Butanol/CNG Dual Fuel Mode With Low and High CNG Substitution Rates in Light Load Operation

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9456 ◽

2016 ◽

Author(s):

Xiangyu Meng ◽

Yuanxu Li ◽

Karthik Nithyanandan ◽

Wuqiang Long ◽

Chia-Fon F. Lee

Keyword(s):

Thermal Efficiency ◽

Substitution Rate ◽

Fuel Combustion ◽

Dual Fuel ◽

Injection Timing ◽

Combustion Mode ◽

Substitution Rates ◽

Low Load ◽

Pilot Fuel ◽

Dual Fuel Combustion

Dual-fuel combustion mode with direct injection of diesel as the pilot fuel and port injection of compressed natural gas (CNG) in compression ignition (CI) engines has been widely investigated to comply with the latest emission regulations. The diesel-CNG dual-fuel combustion mode shows some potential to decrease NOx and soot emissions simultaneously, while it reveals a lower thermal efficiency compared to the pure diesel combustion mode under low load condition. The purpose of the current study is to investigate the possibility of using diesel blended with 1-butanol as the pilot fuel to enhance the engine performance and reduce emissions. Three pilot fuels — B0 (pure diesel), B10 (90% diesel and 10% 1-butanol by volume) and B20 (80% diesel and 20% 1-butanol) with the CNG substitution rates of 50% and 80% were compared at an engine speed of 1200 rpm. The experiments were conducted by sweeping the pilot fuel injection timing from −3 to −18 ° CA ATDC with an equivalent total energy (∼5 bar IMEP). The results illustrated that, for the 50% CNG substitution rate, the dual-fuel operation mode revealed a higher indicated thermal efficiency (ITE) under low load conditions, and B10 can significantly improve the ITE due to the shorter combustion duration. The emission results of B10 showed that it obtained lower THC and CO emissions, but a slightly higher NOx emission. For the 80% CNG substitution rate, the results presented lower ITE, higher THC and lower NOx emissions, comparatively.

Download Full-text

The classification of gasoline/diesel dual-fuel combustion based on the heat release rate shapes and its application in a light-duty single-cylinder engine

International Journal of Engine Research ◽

10.1177/1468087418817676 ◽

2018 ◽

Vol 20 (1) ◽

pp. 69-79 ◽

Cited By ~ 4

Author(s):

Jeongwoo Lee ◽

Sanghyun Chu ◽

Jaegu Kang ◽

Kyoungdoug Min ◽

Hyunsung Jung ◽

...

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Thermal Efficiency ◽

Fuel Combustion ◽

Dual Fuel ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Dual Fuel Combustion ◽

Compression Ignition Combustion

In this research, there are two major sections for analysis: the characteristics of gasoline and diesel dual-fuel combustion and their application to operating load extension with high thermal efficiency and low emissions. All the experiments were completed using a single-cylinder compression ignition engine with 395 cc displacement. In the first section, the dual-fuel combustion modes were classified into three cases by their heat release rate shapes. Staying at 1500 r/min with a total value of 580 J of low heat for each cycle condition, the diesel injection timing was varied from before top dead center with a 6–46 °crank angle with 70% of gasoline fraction based on the low heating value. Among the modes were two suitable dual-fuel combustion modes for a premixed compression ignition. The first suitable mode shows multiple peaks in the heat release rate (mode 2) and the second suitable mode shows a single peak with a “bell-shaped” heat release rate (mode 3). These two dual-fuel combustion types showed a high gross indicated thermal efficiency of up to 46%. Based on the results in the first section, the practical application of dual-fuel premixed compression ignition combustion was investigated considering a high thermal efficiency and a high-load condition. At a 1500 r/min/gross indicated mean effective pressure of 6.5 bar, 48% of the gross indicated thermal efficiency was obtained by using dual-fuel premixed compression ignition combustion mode 3. This mode was typical of a “reactivity controlled compression ignition,” while the nitrogen oxides and the particulate matter emissions satisfied the EURO-6 regulation (0.21 g/kW h and 2.8 mg/m3, respectively). In addition, a high thermal efficiency (45%) with low maximum pressure rise rate, NOx (nitrogen oxides), and particulate matter emissions was obtained at 2000 r/min/gross indicated mean effective pressure 14 bar condition by the adjustment of dual-fuel premixed compression ignition combustion mode 2. As a result, this research contributes to the understanding and practical application of dual-fuel combustion for a light-duty compression ignition engine.

Download Full-text

Effect of swirl ratio on NG/diesel dual-fuel combustion at low to high engine load conditions

Applied Energy ◽

10.1016/j.apenergy.2018.08.017 ◽

2018 ◽

Vol 229 ◽

pp. 375-388 ◽

Cited By ~ 18

Author(s):

Amin Yousefi ◽

Hongsheng Guo ◽

Madjid Birouk

Keyword(s):

Fuel Combustion ◽

Dual Fuel ◽

Swirl Ratio ◽

Engine Load ◽

Dual Fuel Combustion ◽

Load Conditions

Download Full-text

Exploring the potential benefits of high-efficiency dual-fuel combustion on a heavy-duty multi-cylinder engine for SuperTruck I

International Journal of Engine Research ◽

10.1177/14680874211006943 ◽

2021 ◽

pp. 146808742110069

Author(s):

Chloé Lerin ◽

K Dean Edwards ◽

Scott J Curran ◽

Eric J Nafziger ◽

Melanie Moses-DeBusk ◽

...

Keyword(s):

Natural Gas ◽

High Efficiency ◽

Fuel Injection ◽

Fuel Combustion ◽

Dual Fuel ◽

Heavy Duty ◽

Port Fuel Injection ◽

Advanced Combustion ◽

Dual Fuel Combustion

In support of the Daimler SuperTruck I team’s 55% brake thermal efficiency (BTE) pathway goal, researchers at Oak Ridge National Laboratory performed an experimental investigation of the potential efficiency and emissions benefits of dual-fuel advanced combustion approaches on a modified heavy-duty 15-L Detroit™ DD15 engine. For this work, a natural gas port fuel injection system with an independent injection control for each cylinder was added to the DD15 engine. For the dual-fuel strategies investigated, 65%–90% of the total fuel energy was supplied through the added port fuel injection natural gas (NG) fueling system. The remaining fuel energy was supplied by one or more direct injections of diesel fuel using the production high pressure diesel fueling system. The production DD15 air handling system and combustion geometry were unmodified for this study. Efficiency and emissions with dual-fuel strategies including both low temperature combustion (LTC) and non-LTC approaches such as dual fuel direct-injection were investigated along with control authority over combustion phasing. Parametric studies of dual-fuel NG/diesel advanced combustion were conducted in order to experimentally investigate the potential of high-efficiency, dual-fuel combustion strategies to improve BTE in a multi-cylinder engine, understand the potential reductions in engine-out emissions, and characterize the range of combustion phasing controllability. Characterization of mode transitions from mixing-controlled diesel pilot ignition to kinetically controlled ignition is presented. Key findings from this study included a reproducible demonstration of BTE approaching 48% at up to a 13-bar brake mean effective pressure with significant reductions in engine-out NOx and soot emissions. Additional results from investigating load transients in dual-fuel mode and initial characterization of particle size distribution during dual-fuel operation are presented.

Download Full-text