scholarly journals PM and NOX emissions amelioration from the combustion of diesel/ethanol-methanol blends applying exhaust gas recirculation (EGR)

2022 ◽  
Vol 961 (1) ◽  
pp. 012044
Author(s):  
Miqdam T. Chaichan ◽  
Noora S. Ekab ◽  
Mohammed A. Fayad ◽  
Hayder A. Dhahad
Keyword(s):  
Equivalence Ratio ◽  
Fuel Injection ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Operating Parameters ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Oxygenated Fuel ◽  
Oxygenated Fuels ◽  
Gas Recirculation

Abstract The fuel injection timings, equivalence ratio (Ø) and exhaust gas recirculation are considered the most important parameters can effect on combustion process and lower exhaust emissions concentrations. The influence of 15% EGR technology and operating parameters (Ø and injection timing) on NOX emissions and particulate matter (PM) using oxygenated fuel (ethanol and methanol) blends were investigated in this experimental study. The results showed that the NOX emissions concentrations with increasing the equivalence ratio (Ø) and applied EGR for all fuels studied. Besides, the E10 and M10 decreased the PM concentrations compared to the diesel fuel under various equivalence ratios (Ø). The applied EGR increased the PM concentrations, but when combination of oxygenated fuels and EGR leading to the decrease in the PM formation. The NOX emissions concentrations decreased from the combined effect of EGR and oxygenated fuels by 16.8%, 22.91% and 29.5% from the combustion of diesel, M10 and E10, respectively, under various injection timings. It is indicated that NOX emissions decreased with retarded injection timings, while the PM decreased under advanced injection timings.

Diesel Engine Intake Condition Control-Oriented Models for Active Fuel Injection Profile Control

2011 ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
High Fidelity ◽  
Exhaust Gas ◽  
Engine Model ◽  
Profile Control ◽  
Gas Recirculation

Fueling control in Diesel engines is not only of significance to the combustion process in one particular cycle, but also influences the subsequent dynamics of air-path loop and combustion events, particularly when exhaust gas recirculation (EGR) is employed. To better reveal such inherently interactive relations, this paper presents a physics-based, control-oriented model describing the dynamics of the intake conditions with fuel injection profile being its input for Diesel engines equipped with EGR and turbocharging systems. The effectiveness of this model is validated by comparing the predictive results with those produced by a high-fidelity 1-D computational GT-Power engine model.

Characteristics of low temperature and low oxygen diesel combustion with ultra-high exhaust gas recirculation

2007 ◽  
Vol 8 (4) ◽  
pp. 365-378 ◽  
Author(s):  
H Ogawa ◽  
T Li ◽  
N Miyamoto
Keyword(s):  
Oxygen Concentration ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Gas Recirculation ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Cent Oxygen ◽  
Low Oxygen ◽  
Gas Recirculation

Ultra-low NOx and smokeless operation at higher loads up to half of the rated torque is attempted with large rates of cold exhaust gas recirculation (EGR). NOx decreases below 6 ppm (0.05 g/kW h) and soot significantly increases when first decreasing the oxygen concentration to 16 per cent with cold EGR. However, after peaking at 12–14 per cent oxygen, soot then decreases sharply to essentially zero at 9–10 per cent oxygen while maintaining ultra-low NOx, regardless of fuel injection quantity and injection pressure. However, at higher loads, with the oxygen concentration below 9–10 per cent, the air-fuel ratio has to be over-rich to exceed half of the rated torque, and thermal efficiency, CO, and THC deteriorate significantly. As the EGR rate increases, exhaust gas emissions and thermal efficiency vary with the intake oxygen content rather than with the excess air ratio. Longer ignition delays due to either advancing or retarding the injection timing reduced the smoke emissions, but advancing the injection timing has the advantages of maintaining the thermal efficiency and preventing misfiring. A reduction in the compression ratio is effective to reduce the in-cylinder temperature and increase the ignition delay as well as to expand the smokeless combustion range in terms of EGR and i.m.e.p. (indicated mean effective pressure).

Biodiesel Combustion and Emissions in Engines Using Modern Common-Rail Fuel Injection Systems

2008 ◽  
Author(s):  
Prashanth K. Karra ◽  
Matthias K. Veltman ◽  
Song-Charng Kong
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Gas Recirculation ◽  
Common Rail ◽  
Injection System ◽  
Injection Timing ◽  
Fuel Injection System ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Gas Recirculation

This study performed experimental testing of a multi-cylinder diesel engine using different blends of biodiesel and diesel fuel. The engine used an electronically-controlled common-rail fuel injection system to achieve a high injection pressure. The operating parameters that were investigated included the injection pressure, injection timing, and exhaust gas recirculation rate. Results showed that biodiesel generally reduced soot emissions and increased NOx emissions. The increase in NOx emissions was not due to the injection timing shift when biodiesel was used because the present fuel injection system was able to give the same fuel injection timing. At high exhaust gas recirculation rates, emissions using regular diesel and 20% biodiesel blends are very similar while 100% biodiesel produces relatively different emission levels. Therefore, the increase in NOx emissions may not be a concern when 20% biodiesel blends are used with high exhaust gas recirculation rates in order to achieve low temperature combustion conditions.

Model-based control of diesel engines with multiple fuel injections

2017 ◽  
Vol 19 (2) ◽  
pp. 257-265 ◽  
Author(s):  
Yudai Yamasaki ◽  
Ryosuke Ikemura ◽  
Shigehiko Kaneko
Keyword(s):  
Fuel Injection ◽  
Exhaust Gas Recirculation ◽  
Gas Pressure ◽  
Combustion Model ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Diesel Combustion ◽  
Target Value ◽  
Pressure Peak ◽  
Gas Recirculation

We developed a feed-forward controller for a conventional diesel combustion engine with triple fuel injection and experimentally evaluated its performance. A combustion model that discretizes an engine cycle into a number of representative points to achieve a light calculation load is embedded into the controller; this model predicts the in-cylinder gas-pressure-peak timing with information about the operating condition obtained from the engine control unit. The controller calculates the optimal main-fuel-injection timing to control the in-cylinder gas-pressure peak using the prediction result as a controller with a single input and output. The controller’s performance was evaluated by experiments using a four-cylinder diesel engine under changing the target value of the in-cylinder gas-pressure-peak timing during a target-following test and the performance was also evaluated under changing the exhaust gas recirculation ratio at the constant target value of the in-cylinder gas-pressure-peak timing for the disturbance-response test. It was found that the controller could calculate the optimal main-injection timing over a cycle and maintain the targeted in-cylinder gas-pressure-peak timing even when the target value or exhaust gas recirculation changed. The combustion model was also shown to be fast enough at predicting diesel combustion for onboard control.

Combustion of Hydrotreated Vegetable Oil in a Diesel Engine: Sensitivity to Split Injection Strategy and Exhaust Gas Recirculation

2020 ◽  
Author(s):  
Maciej Mikulski ◽  
Jacek Hunicz ◽  
Aneesh Vasudev ◽  
Arkadiusz Rybak ◽  
Michał Gęca
Keyword(s):  
Vegetable Oil ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Exhaust Gas Recirculation ◽  
Injection Timing ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Injection Strategy ◽  
Soot Emissions ◽  
Gas Recirculation

Abstract This work explores the potential to optimize advanced common-rail engines for operation with hydrotreated vegetable oil (HVO). The single-cylinder engine research focuses on adjusting the injection strategy and external exhaust gas recirculation (EGR) to achieve the optimum performance-emissions trade-off using HVO. The engine is operated at a fixed rotational speed of 2000 rpm and under constant load (net indicated mean effective pressure of 0.45 MPa). Split fuel-injection strategy is used: main injection timing is fixed but pilot injection is varied both in terms of timing and quantity. The engine tests, without turbocharging, are conducted under non-EGR conditions and using approximately 27% EGR rate. Results with HVO are compared with results when using diesel fuel. Within the constraints of a single, representative operating point, the results highlight that when using the factory map-based injection strategy, HVO offers soot emissions below 0.015 g/kWh, a 50% reduction when compared to diesel fuel. Nitrogen oxides (NOx) emissions at the same conditions are, however, 10% higher than for diesel fuel. That correlates with higher peak in-cylinder pressures and temperatures. Advancing the pilot HVO injection reduced NOx emissions to the level of the diesel baseline, and although soot emissions increased, they remained 25% lower than with diesel. Interestingly, the two tested fuels exhibited very different responses to EGR. Generally, at 27% EGR, HVO produced twice as much soot as diesel. The heat release analysis indicates this sensitivity to EGR stems from HVO’s higher cetane number causing faster auto-ignition, resulting in less premixed combustion and hence producing more soot. Generally, HVO offered more complete combustion than diesel fuel. Regardless of pilot fuel injection strategy, CO emission was reduced by approximately 50% with HVO for both EGR and non-EGR conditions. HVO also benefits emissions of unburned hydrocarbons, in terms of both total values and also unlegislated aldehydes and aromatics.

Measurement of Flame Frequency Response Functions Under Exhaust Gas Recirculation Conditions

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Joseph Ranalli ◽  
Don Ferguson
Keyword(s):  
Transfer Function ◽  
Carbon Capture ◽  
Transfer Functions ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Flame Response ◽  
Gas Recirculation

Exhaust gas recirculation has been proposed as a potential strategy for reducing the cost and efficiency penalty associated with postcombustion carbon capture. However, this approach may cause as-yet unresolved effects on the combustion process, including additional potential for the occurrence of thermoacoustic instabilities. Flame dynamics, characterized by the flame transfer function, were measured in traditional swirl stabilized and low-swirl injector combustor configurations, subject to exhaust gas circulation simulated by N2 and CO2 dilution. The flame transfer functions exhibited behavior consistent with a low-pass filter and showed phase dominated by delay. Flame transfer function frequencies were nondimensionalized using Strouhal number to highlight the convective nature of this delay. Dilution was observed to influence the dynamics primarily through its role in changing the size of the flame, indicating that it plays a similar role in determining the dynamics as changes in the equivalence ratio. Notchlike features in the flame transfer function were shown to be related to interference behaviors associated with the convective nature of the flame response. Some similarities between the two stabilization configurations proved limiting and generalization of the physical behaviors will require additional investigation.

scholarly journals Learning reference governor for cycle-to-cycle combustion control with misfire avoidance in spark-ignition engines at high exhaust gas recirculation–diluted conditions

2020 ◽  
Vol 21 (10) ◽  
pp. 1819-1834
Author(s):  
Bryan P Maldonado ◽  
Nan Li ◽  
Ilya Kolmanovsky ◽  
Anna G Stefanopoulou
Keyword(s):  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Operating Conditions ◽  
Intake Manifold ◽  
Exhaust Gas ◽  
Model Free ◽  
Recirculation Rate ◽  
Valve Position ◽  
Gas Recirculation ◽  
Reference Governor

Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.

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