scholarly journals Effects of methane ratio on MPDF (micro-pilot dual-fuel) combustion characteristic in a heavy-duty single cylinder engine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Minhoo Choi ◽  
Khawar Mohiuddin ◽  
Sungwook Park
Keyword(s):  
Fuel Mixture ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Cylinder Pressure ◽  
Mixture Ratio ◽  
Single Cylinder ◽  
Peak Cylinder Pressure ◽  
Methane Mixture ◽  
Dual Fuel Combustion ◽  
Combustion Speed

AbstractIn this study, the characteristics of micro-pilot dual-fuel combustion with respect to the fuel mixture ratio in a single cylinder dual-fuel engine have been investigated. In order to analyze the characteristics of micro-pilot dual-fuel combustion, a metal engine and an optical single cylinder dual-fuel engine were used. The fuel mixture ratio was varied for experimental purposes; the diesel was directly injected into combustion chamber and the methane gas was supplied via intake port. The present study reports that increasing the methane mixture ratio from 0 to 97.67% changes the diesel combustion to pre-mixed combustion. As a result, the peak cylinder pressure was increased from 184 to 198 bar, and the rate of heat release was greatly advanced. In the MPDF condition, the nitrogen oxides emissions were reduced by about 90%p, and the fuel conversion efficiency increased about 5%p because of the low combustion temperature of pre-mixed combustion. However, for the same reason, the hydrocarbon emissions were increased about 95%p. The fastest combustion speed was found form the results of methane mixture ratio between 40 and 80%. In the condition of diesel combustion and micro-pilot dual-fuel combustion, the combustion periods of middle and initial were increased, respectively, resulting in the low combustion speed. The standard deviation of peak cylinder pressure, which represents the combustion variation, was correlated with initial combustion period. While the condition of methane gas mixture ratio between 40 and 80% shows the lowest combustion variation, the highest combustion variation was occurred by MPDF condition. Through the optical engine experiment, it can be found that the cycle to cycle combustion variation is ascribed to the turbulent flow and the variation of ignition position. The combustion images show that the unpredictable characteristics of the ignition position and slow flame propagation speed caused the combustion variation in micro-pilot dual-fuel combustion.

scholarly journals Closed-loop control of a dual-fuel engine working with different combustion modes using in-cylinder pressure feedback

2019 ◽  
Vol 21 (3) ◽  
pp. 484-496 ◽  
Author(s):  
Carlos Guardiola ◽  
Benjamín Pla ◽  
Pau Bares ◽  
Alvin Barbier
Keyword(s):  
Closed Loop ◽  
Combustion Engine ◽  
Fuel Combustion ◽  
Operating Conditions ◽  
Dual Fuel ◽  
Maximum Pressure ◽  
Cylinder Pressure ◽  
Pressure Derivative ◽  
Combustion Modes ◽  
Dual Fuel Combustion

This work presents a closed-loop combustion control concept using in-cylinder pressure as a feedback in a dual-fuel combustion engine. At low load, reactivity controlled compression ignition combustion was used while a diffusive dual-fuel combustion was performed at higher loads. The aim of the presented controller is to maintain the indicated mean effective pressure and the combustion phasing at a target value, and to keep the maximum pressure derivative under a limit to avoid engine damage in all the combustion modes by cyclically adapting the injection settings. Various tests were performed at steady-state conditions showing good abilities to fulfil the expected operating conditions but also to reject disturbances such as intake pressure or exhaust gas recirculation variations. Finally, the proposed control strategy was tested during a load transient resulting in a combustion switching-mode and the results exhibited the closed-loop potential for controlling such combustion concept.

Performance and Emissions Characteristics of Diesel-Ignited Gasoline Dual Fuel Combustion in a Single-Cylinder Research Engine

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
U. Dwivedi ◽  
C. D. Carpenter ◽  
E. S. Guerry ◽  
A. C. Polk ◽  
S. R. Krishnan ◽  
...  
Keyword(s):  
Injection Pressure ◽  
Fuel Combustion ◽  
Injection System ◽  
Dual Fuel ◽  
Heterogeneous Combustion ◽  
Boost Pressure ◽  
Fuel Injector ◽  
Single Cylinder ◽  
Diesel Injection ◽  
Dual Fuel Combustion

Diesel-ignited gasoline dual fuel combustion experiments were performed in a single-cylinder research engine (SCRE), outfitted with a common-rail diesel injection system and a stand-alone engine controller. Gasoline was injected in the intake port using a port-fuel injector. The engine was operated at a constant speed of 1500 rev/min, a constant load of 5.2 bar indicated mean effective pressure (IMEP), and a constant gasoline energy substitution of 80%. Parameters such as diesel injection timing (SOI), diesel injection pressure, and boost pressure were varied to quantify their impact on engine performance and engine-out indicated specific nitrogen oxide emissions (ISNOx), indicated specific hydrocarbon emissions (ISHC), indicated specific carbon monoxide emissions (ISCO), and smoke emissions. Advancing SOI from 30 degrees before top dead center (DBTDC) to 60 DBTDC reduced ISNOx from 14 g/kW h to less than 0.1 g/kW h; further advancement of SOI did not yield significant ISNOx reduction. A fundamental change was observed from heterogeneous combustion at 30 DBTDC to “premixed enough” combustion at 50–80 DBTDC and finally to well-mixed diesel-assisted gasoline homogeneous charge compression ignition (HCCI)-like combustion at 170 DBTDC. Smoke emissions were less than 0.1 filter smoke number (FSN) at all SOIs, while ISHC and ISCO were in the range of 8–20 g/kW h, with the earliest SOIs yielding very high values. Indicated fuel conversion efficiencies were ∼ 40–42.5%. An injection pressure sweep from 200 to 1300 bar at 50 DBTDC SOI and 1.5 bar intake boost showed that very low injection pressures lead to more heterogeneous combustion and higher ISNOx and ISCO emissions, while smoke and ISHC emissions remained unaffected. A boost pressure sweep from 1.1 to 1.8 bar at 50 DBTDC SOI and 500 bar rail pressure showed very rapid combustion for the lowest boost conditions, leading to high pressure rise rates, higher ISNOx emissions, and lower ISCO emissions, while smoke and ISHC emissions remained unaffected by boost pressure variations.

scholarly journals Capturing Pressure Oscillations in Numerical Simulations of Internal Combustion Engines

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Sreenivasa Rao Gubba ◽  
Ravichandra S. Jupudi ◽  
Shyam Sundar Pasunurthi ◽  
Sameera D. Wijeyakulasuriya ◽  
Roy J. Primus ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Combustion Engines ◽  
Cylinder Pressure ◽  
Pressure Oscillations ◽  
Numerical Predictions ◽  
Medium Speed ◽  
Dual Fuel Combustion ◽  
The Mean

In an earlier publication (Jupudi et al., 2016, “Application of High Performance Computing for Simulating Cycle-to-Cycle Variation in Dual-Fuel Combustion Engines,” SAE Paper No. 2016-01-0798), the authors compared numerical predictions of the mean cylinder pressure of diesel and dual-fuel combustion, to that of measured pressure data from a medium-speed, large-bore engine. In these earlier comparisons, measured data from a flush-mounted in-cylinder pressure transducer showed notable and repeatable pressure oscillations which were not evident in the mean cylinder pressure predictions from computational fluid dynamics (CFD). In this paper, the authors present a methodology for predicting and reporting the local cylinder pressure consistent with that of a measurement location. Such predictions for large-bore, medium-speed engine operation demonstrate pressure oscillations in accordance with those measured. The temporal occurrences of notable pressure oscillations were during the start of combustion and around the time of maximum cylinder pressure. With appropriate resolutions in time steps and mesh sizes, the local cell static pressure predicted for the transducer location showed oscillations in both diesel and dual-fuel combustion modes which agreed with those observed in the experimental data. Fast Fourier transform (FFT) analysis on both experimental and calculated pressure traces revealed that the CFD predictions successfully captured both the amplitude and frequency range of the oscillations. Resolving propagating pressure waves with the smaller time steps and grid sizes necessary to achieve these results required a significant increase in computer resources.

scholarly journals Capturing Pressure Oscillations in Numerical Simulations of Internal Combustion Engines

2017 ◽  
Author(s):  
Sreenivasa Rao Gubba ◽  
Ravichandra S. Jupudi ◽  
Shyam Sundar Pasunurthi ◽  
Sameera D. Wijeyakulasuriya ◽  
Roy J. Primus ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Cylinder Pressure ◽  
Pressure Oscillations ◽  
Engine Operation ◽  
Numerical Predictions ◽  
Medium Speed ◽  
Dual Fuel Combustion ◽  
The Mean

In an earlier publication [1] the authors compared numerical predictions of the mean cylinder pressure of diesel and dual-fuel combustion, to that of measured pressure data from a medium-speed, large-bore engine. In these earlier comparisons, measured data from a flush-mounted in-cylinder pressure transducer showed notable and repeatable pressure oscillations which were not evident in the mean cylinder pressure predictions from CFD. In this paper, the authors present a methodology for predicting and reporting the local cylinder pressure consistent with that of a measurement location. Such predictions for large-bore, medium-speed engine operation demonstrate pressure oscillations in accordance with those measured. The temporal occurrences of notable pressure oscillations were during the start of combustion and around the time of maximum cylinder pressure. With appropriate resolutions in time steps and mesh sizes, the local cell static pressure predicted for the transducer location showed oscillations in both diesel and dual-fuel combustion modes which agreed with those observed in the experimental data. Fast Fourier Transform (FFT) analysis on both experimental and calculated pressure traces revealed that the CFD predictions successfully captured both the amplitude and frequency range of the oscillations. Resolving propagating pressure waves with the smaller time steps and grid sizes necessary to achieve these results required a significant increase in computer resources.

Influence of Swirl Ratio on Diesel-Methane Dual Fuel Combustion: A CFD Investigation

2017 ◽  
Author(s):  
P. R. Jha ◽  
K. K. Srinivasan ◽  
S. R. Krishnan
Keyword(s):  
Carbon Monoxide ◽  
Heat Release ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Swirl Ratio ◽  
Cycle Simulation ◽  
Low Load ◽  
Dual Fuel Combustion

Dual fuel combustion has garnered attention in recent years because of its potential for reducing emissions of oxides of nitrogen (NOx) and particulate matter (PM) while sustaining diesel-like fuel conversion efficiencies. However, most dual fuel combustion strategies suffer from higher engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions, leading to poor combustion efficiencies, especially at low loads. The present work examined computationally the effect of in-cylinder swirl on diesel-ignited methane dual fuel combustion with a focus on devising strategies for improving part-load combustion efficiencies. For this purpose, diesel-methane dual fuel combustion was studied on a heavy-duty single cylinder research engine (SCRE) platform using CONVERGE computational fluid dynamics (CFD) software. A typical low load condition (IMEP = 5.1 bar) was selected at an engine speed of 1500 rpm and a relatively high methane percentage energy substitution (PES) of 80 percent (because experiments show poorer combustion efficiencies at high methane PES) at a nominal diesel injection timing of 2 degrees BTDC (358 CAD). The closed cycle simulation was first validated with experimental results (cylinder pressure and heat release histories as well as engine-out exhaust emissions) for neat diesel and diesel-methane dual fuel combustion, respectively. Subsequently, the influence of increasing swirl ratio from 0 to 1.5 on diesel-methane dual fuel combustion was characterized. Analysis of the computational results showed that peak cylinder pressure and heat release rate increased with increasing swirl ratio while the combustion duration (as determined by CA10-80) decreases from 25 CAD at a swirl ratio of 0.05 to nearly 15 CAD at a swirl ratio of 1.5. Indicated-specific hydrocarbon (ISHC) and indicated-specific carbon monoxide (ISCO) emissions decreased by about 60 percent and 50 percent, respectively, when swirl ratio was increased from 0.05 to 1.2; however, these reductions were accompanied by a 26 percent increase in indicated-specific NOx (ISNOx) emissions under these conditions. Therefore, the present study indicates that swirl optimization is a potentially viable strategy for reducing engine-out HC and CO emissions and for improving low-load combustion efficiencies in dual fuel engines, assuming additional NOx mitigation strategies are also employed simultaneously.

Performance and Emissions Characteristics of Diesel-Ignited Gasoline Dual Fuel Combustion in a Single Cylinder Research Engine

2013 ◽  
Author(s):  
U. Dwivedi ◽  
C. D. Carpenter ◽  
E. S. Guerry ◽  
A. C. Polk ◽  
S. R. Krishnan ◽  
...  
Keyword(s):  
Injection Pressure ◽  
Fuel Combustion ◽  
Injection System ◽  
Dual Fuel ◽  
Heterogeneous Combustion ◽  
Boost Pressure ◽  
Fuel Injector ◽  
Single Cylinder ◽  
Diesel Injection ◽  
Dual Fuel Combustion

Diesel-ignited gasoline dual fuel combustion experiments were performed in a single-cylinder research engine (SCRE), outfitted with a common-rail diesel injection system and a stand-alone engine controller. Gasoline was injected in the intake port using a port-fuel injector. The engine was operated at a constant speed of 1500 rev/min, a constant load of 5.2 bar IMEP, and a constant gasoline energy substitution of 80%. Parameters such as diesel injection timing (SOI), diesel injection pressure, and boost pressure were varied to quantify their impact on engine performance and engine-out ISNOx, ISHC, ISCO, and smoke emissions. Advancing SOI from 30 DBTDC to 60 DBTDC reduced ISNOx from 14 g/kWhr to less than 0.1 g/kWhr; further advancement of SOI did not yield significant ISNOx reduction. A fundamental change was observed from heterogeneous combustion at 30 DBTDC to “premixed enough” combustion at 50–80 DBTDC and finally to well-mixed diesel-assisted gasoline HCCI-like combustion at 170 DBTDC. Smoke emissions were less than 0.1 FSN at all SOIs, while ISHC and ISCO were in the range of 8–20 g/kWhr, with the earliest SOIs yielding very high values. Indicated fuel conversion efficiencies were ∼ 40–42.5%. An injection pressure sweep from 200 to 1300 bar at 50 DBTDC SOI and 1.5 bar intake boost showed that very low injection pressures lead to more heterogeneous combustion and higher ISNOx and ISCO emissions, while smoke and ISHC emissions remained unaffected. A boost pressure sweep from 1.1 to 1.8 bar at 50 DBTDC SOI and 500 bar rail pressure showed very rapid combustion for the lowest boost conditions, leading to high pressure rise rates, higher ISNOx emissions, and lower ISCO emissions, while smoke and ISHC emissions remained unaffected by boost pressure variations.

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