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Article

Influence of EGR and Acoustic Waves on Particles and Other Emissions of IC Engine Powered with Diesel and RME Fuels

by
Sai Manoj Rayapureddy
1,* and
Jonas Matijošius
2
1
Department of Mobile Machinery and Railway Transport, Faculty of Transport Engineering, Vilnius Gediminas Technical University, Plytinės Str. 25, 10105 Vilnius, Lithuania
2
Mechanical Science Institute, Vilnius Gediminas Technical University, Plytinės Str. 25, 10105 Vilnius, Lithuania
*
Author to whom correspondence should be addressed.
Fuels 2025, 6(3), 67; https://doi.org/10.3390/fuels6030067
Submission received: 20 July 2025 / Revised: 7 August 2025 / Accepted: 2 September 2025 / Published: 17 September 2025
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Abstract

To achieve the goal of climate neutrality set by the European Union, it is important to find an efficient strategy to simultaneously lower nitrogen oxide, carbon monoxide, and particle emissions. When a portion of exhaust gas is reintroduced back into the combustion chamber, it reduces the combustion temperature. This reduces NOX emissions but has a negative impact on CO and particle emissions due to the lower concentration of O2. Reducing the combustion temperature can also indirectly influence particle formation. By including an oxygen-rich alternative fuel, CO emissions are reduced by 28% and 33% at 60 and 90 Nm, respectively. To further reduce particle emissions, which have significant health risks, acoustic waves are introduced to achieve better filtration through conventional DPFs that filter particles with larger diameters. With 21 kHz of acoustic frequency and 0% EGR, a 6% increase in large particles is observed. With moderate rise in the recirculation percentage, a higher combined efficiency of EGR and acoustic waves is observed. With 21 kHz acoustic frequency and 10% EGR, a 73% increase in larger particles is observed at lower loads and a 32% increase at higher loads is observed. Simultaneous emission reduction can be achieved by combining the benefits of using oxygen-rich fuel, acoustics, and EGR at a moderate rate.

1. Introduction

The world is moving towards green vehicles, but diesel engines are still dominating the transport sector. The European Union is committed to lowering greenhouse gas emissions by 55% by 2030 [1,2]. However, the emissions of the diesel combustion process are a global health hazard that also pollute the environment [3]. NOX emissions are a major contributor to air pollution and acid rain, while particle emissions constitute an imminent hazard as they interact directly with human skin and can even enter the bloodstream and respiratory system [4,5]. Parallel reduction of nitrogen oxide and particle emissions poses a significant challenge, as strategies to reduce one often negatively influence the other [6]. In wake of this problem, researchers are finding ways to counteract this problem while also maintaining the performance of the engine.
Exhaust gas recirculation (EGR) is an important phenomenon that can influence the concentration of exhaust emissions along with the combustion process [7,8]. It is the technology used particularly to lower the combustion temperatures by reintroducing a fraction of the exhaust gases into the air intake stream [9]. The efficiency and effectiveness of the combustion process is often observed with higher loads and lower speeds as the recirculated exhaust gases get mixed with the air intake [10]. At higher EGR rates, the unburnt hydrocarbons increase because of the oxygen reduction in the air–fuel mixture. Due to the reburning of unburnt hydrocarbons with EGR at lower loads, the brake thermal efficiency can be increased. At partial loads, fuel consumption is below the standard BSFC. At higher loads, the BSFC increases due to the change in air fuel mixtures affected by the reduction in O2 availability [11].
However, reducing the combustion chamber temperature may increase the chances of higher particle formation. The particles are impacted by the change in combustion efficiency and the diluted air–fuel mixture due to the influence of exhaust recirculation [12,13]. In research carried out on a modified diesel engine tested at varying EGR rates between 0 and 20%, NOX emissions are found to be decreasing at a rate of little more than 1%, but CO and smoke are observed to increase at a rate of 5% and 13%, respectively [14]. Particle emissions have been found to increase with higher EGR rates due to incomplete combustion [6]. The increase in particle emissions with an increase in the EGR rates can be countered with oxygenated fuels. Oxygen-rich fuel mixtures have lower calorific value compared to diesel, therefore less heat is released during combustion, which also reduces the NOX emissions [7,15,16]. Research focused primarily on reducing exhaust emissions by combining the emission reduction system at a suggested 10–20% EGR rate with a diesel particulate filter (DPF) to effectively reduce HC, CO, and particle emissions [17].
The limitations of the DPF are that conventional filters are not efficient in capturing fine particles (which are typically less than 2.5 μm). There is a worldwide interest in developing new and effective advances in particulate filter technology [18,19]. The efficiency of filtering fine particles by using DPFs can be increased by a process called particle aggregation. Agglomeration is where the movement of the particles is influenced by an external source (thermal, acoustics, or charge fields), and an environment is created to allow the particles to collide and agglomerate [20]. Due to the chemical, structural, and sticky nature, the particles are usually agglomerated and have a larger size [21]. Using acoustics is one such predominant technique to achieve better particle filtration by inducing acoustic waves that excite particles and collide with each other to achieve better filtration through DPF [22,23,24,25,26]. Most of the available research implemented the acoustic technique in large-scale industries, either to reduce smoke from coal ash or industry emissions [22,23,25,27]. Very few tests were conducted to test the impact of acoustics on particles emitted from the engine. An experiment carried out to test the influence of ultrasound on the filtration process of the car muffler proved that the introduction of sound waves reduces the smoke content [28]. When acoustics are maintained at 148 dB, a 10% increase in particle capture efficiency is observed in research particularly focused on reducing fine particles [27]. Recent research demonstrated a reduction in large size particles at nearly 100% and small particles by almost 50% when the acoustics are maintained at 21.4 kHz [29]. Another experimental observation from the same author concluded that, with the application of acoustics, smaller particles are observed to decrease with an increase in the number of large particles, confirming agglomeration [30].
This research article focuses on studying the combined impact of EGR and acoustic waves on total exhaust emissions (primarily NOX, CO, and particles). NOX is the primary benefactor of increasing the EGR rate, and by including oxygen-rich alternative fuel, a positive influence is expected on CO and particle emissions. To further reduce particle emissions, which have a direct adverse impact on human health, acoustic waves are introduced to achieve better filtration through conventional DPFs that filter particles with larger diameters.

2. Materials and Methods

2.1. Testing Equipment

The test bench consists of a VW-Audi 1Z 1.9-L TDI diesel engine equipped with an electronically regulated distribution fuel pump. It is a 4-cylinder engine with a torque of 182 Nm at 2000 rpm. It operates on a single injection strategy with a piston stroke of 95.5 mm. The schematic representation of the test equipment is provided in Figure 1. Further engine specifications are available in details in some of the previous research papers [31,32,33].
Engine exhaust, which was directed through the black tube presented in Figure 2, is then passed through the in-house built acoustic housing setup, where the particles and other emissions are measured and recorded under different test conditions, as presented in Figure 1 and Figure 2. The red lines indicate the acoustic waves imposed on the exhaust and the black lines represent the flow of exhaust gases through the setup. The acoustic housing setup consists of longitudinal chambers, emission measuring equipment, acoustic generators controlled by a computer and PDUS210 ultrasonic driver, as further presented in Figure 2.
Acoustics were maintained at 100 V of voltage, 140 dB of sound pressure level, and a ~21 kHz frequency, throughout acoustic tests. Previous experiments are observed to have a sound level at a range of 140–150 dB and the frequency of 21 kHz is rounded off from the recent experiment conducted on a similar model and test conditions [23,27,29,30]. The tests was conducted in the laboratory of Faculty of Transport Engineering, Vilnius Tech, Lithuania.

2.2. Fuels Used and Test Environment

Given the significance of oxygen in emission formation, rapeseed methyl ester (RME/RME100) is selected to be compared to diesel fuel (D100) among other alternative fuel options. The physicochemical characteristics of the fuels tested are summarized in Table 1. Cost and availability are two primary parameters considered when choosing the alternative fuel to compare with diesel. The tests were subjected to three EGR rates of 0%, 10%, and 20%. The influence of exhaust recirculation on the formation of particles and other emissions is recorded at lower and higher loads (60 and 90 Nm, respectively) for both fuels. Lower loads are categorized under the driving conditions with speed 40–50 km/h in a city where the conditions are ~30% load. 90 Nm falls under the moderate acceleration (90 km/h) condition of ~50% load. The engine speed is maintained at 2000 rpm.
For the other emissions presentation, the X axis represents the change in EGR percentage, while the Y axis represents CO, NO, NO2, NOX, SO2, and O2 emissions. For particle emission changes, the change in particle sizes with EGR rate is presented on the X axis and the number of particles on the Y axis. As the observed particle numbers are in the higher range of hundred thousand, for the relative understanding of the change in particles, it is measured in terms of percentage and is presented using a logarithmic scale. The changes in other emissions are measured in their units (ppm). All emissions with respect to the EGR rate are shown on X axis while the change is shown on Y axis. Each test was performed three times, and the mean values of the results were presented.
Two measuring systems were used to measure the emissions. The particle number was measured using Fluke 985 Air Particle Counter in six channels (between 0.3 and 10 μm as presented in the results). The efficiency of measuring particles of size 0.3 μm is 50% and for those of size higher than 0.45 μm, the efficiency is 100%. The Testo 380 measuring system is used to measure other emissions (CO, O2, SO2, NO, NO2, and NOX). The measurement accuracy is in accordance with VDI 4206-2. The measurement error of CO and O2 is 0.01% vol; NOX is 1 ppm.

3. Results

3.1. Total Emissions of Diesel and RME Fuel

With an increase in load, CO is found to increase at all EGR rates tested due to the rich air–fuel mixtures. At 60 and 90 Nm, there is no substantial variation in the CO concentration when the EGR rate is increased from 0 to 10%, but a 62% increase is observed at 60 Nm and a 103% increase in emissions is observed at 90 Nm when the rate is increased to 20%, as presented in Figure 3a and Figure 4a. With the recirculation of exhaust gases, there is less oxygen available for combustion; these results give to a rise in CO emissions. This observation is consistent with recent research results [13,34].
There is a 13% increase in average NOX emissions with increasing load (at all EGR rates). Consistent with previous studies, NOX emissions are found to consistently decrease with increase in exhaust recirculation [7,14]. At a higher load, with a rise in the EGR rate of 10%, there is 68% decrease in the NO2 concentration; this number is further reduced by 25% at 20% EGR. At 90 Nm, there is a 16% fall of NOX emissions when the recirculation increases from 0 to 10%; similarly, a 10% decrease in NOX emissions at 60 Nm is observed when the recirculation increased by 10% to 20%. In other cases, there is a small increase in emissions at the rate of 3–5%. As presented in Figure 3a and Figure 4a, while there is a decreasing trend observed for NOX emissions at both loads, the reduction is found to be highest at 90 Nm.
SO2 emissions are found to be zero under almost all tested conditions. As expected, O2 has been found to gradually decrease with increasing EGR rate [7]. When the EGR rate is increased to 10%, O2, which is observed to be 16 ppm and 13 ppm without recirculation, is found to decrease to 3 and 9% at 60 and 90 Nm loads, respectively. With a further increase in EGR to 20%, there is a further decrease of 14 and 10%, respectively.
As presented in Figure 3b, at 60 Nm load, a 3% increase in 0.3 μm size is observed with an increase in the EGR rate from 0 to 10%. But with a further increase in EGR to 20%, it was found that the number of particles of sizes 0.3–1 μm was found to decrease with an average increase of 48% in the number of particles between the size range of 2 and 10 μm. Also, at higher loads, with an increase in exhaust recirculation to 10%, 0.3 and 0.5 μm particles increase in number. Additionally, as presented in Figure 4b, a substantial increase in 10 μm particles are observed. In contrast to the trend observed at 60 Nm, with increase in exhaust recirculation to 20%, increase in particles are observed with a size range of 0.5–2 μm. This shift in the particle size distribution to a larger size is consistent with recent empirical findings [35,36,37].
By replacing diesel fuel with RME100, CO is reduced by 33% at 90 Nm and 28% at 60 Nm; this tendency is due to the influence of oxygenated fuels on complete combustion [38]. A 5% reduction in average NOX emissions (at all EGR rates) is observed at higher loads due to its shorter ignition delay, as presented in Figure 5a [39]. Due to the availability of oxygen in RME100, an increase of 4% is observed at 60 Nm (as presented in Table 1 and Figure 6a). This plays an important role in promoting complete combustion and leads to higher temperatures, resulting in increased NOX emissions [7]. The emission reduction due to the increase in EGR rate is dominated by the influence of increased oxygen content of the fuel, resulting in higher emissions. Interestingly, SO2 emissions are found to be higher in fuel with low sulfur content like RME under all tested conditions. The trace amounts of sulfur that are present in RME, when combusted, can produce SO2 emissions. On the other hand, D100 is desulfurized to meet the EU emissions standards, leading to a nil sulfur content [40,41].
NO emissions, which contribute to the majority of NOX emissions, are found to decrease by 5% with an increase in EGR from 0 to 10%, and a further decrease of 6% is observed when the rate is further increased to 20% at lower loads. At 90 Nm, there is a 9% decrease in NO emissions when the EGR rate increases from 10 to 20%. NO2 was found to decrease by 22 and 43 % when EGR changed to 10% and 20%, respectively. This reduction is consistent with previous studies and is related to a reduced ignition delay when compared to diesel fuel [42]. In comparison with diesel, a slight increase in O2 is observed but is further reduced with a rise in the EGR rate, as observed for diesel fuel. Without recirculation, oxygen is observed to be higher, at 16 ppm and 15 ppm at 60 and 90 Nm, respectively.
For RME100, at a lower load of 60 Nm, with a rise in the exhaust recirculation to 10%, the 0.3 μm sized particles are found to increase as observed for diesel fuel. When the exhaust recirculation is increased to 20%, particles in the range of 0.3 to 2 μm are observed to have an average fall of 41% combined with an increase in particles of sizes 5 and 10 μm at 18% and 67%, respectively, as presented in Figure 5b. At a higher tested load, when the recirculation rate is increased to 10%, a significant reduction in large particles is observed, along with a considerable rise in 0.5–2 μm sized particles. With further increase in the recirculation rate to 20%, particles between the size range of 1 to 5 μm are found to decrease at an average of 21% with an observable increase in particles less than 1 μm, as shown in Figure 6b. The influence of EGR on RME fuel causes small particles to collide and agglomerate. This results in the formation of large-sized particles and this concentration can be positively influenced by the oxygen content in the fuel [43].
At lower EGR rates and higher loads, D100 produces higher NOX and CO emissions. RME100 provides better combustion properties, but the oxygen-rich nature of the fuel might negatively influence NOX, especially when the EGR benefits are overcompensated by the oxygen content. The EGR rate effectively reduces NOX, but increases CO emissions as the air intake mass flow rate is reduced with rise in the exhaust recirculation, thus decreasing the air–fuel mixture resulting in higher CO emissions [44]. The particles are reduced when RME is used, but the load properties remain the same for both the fuels tested [42].

3.2. Impact of Acoustic Waves on Emissions

Acoustic waves can induce turbulence and disrupt the natural flow of exhaust gases passing through the acoustic setup [28]. The impact of acoustic waves on particle emissions is a widely researched area. In this article, the influence of acoustics is combined and studied in terms of EGR rate and the increased influence on particle emissions. Although there is no primary research or effective evidence proving the direct impact of acoustics on other gaseous pollutants, the observed results are presented for further research.
At 20% EGR, with an acoustic frequency of 21 kHz, the reduction in CO emissions is found to be consistent between both load conditions [28]. While there is a notable decrease in CO emissions, higher loads were found to provide better results. No considerable and consistent changes were observed in NOX emissions in the presence of acoustics.
For diesel fuel at lower loads and at 0% EGR, the 5 μm sized particles are found to increase by 8% and the 10 μm sized particles increase by 4%, as presented in Figure 7b. The research results prove that using acoustic waves is an efficient way to lower fine particle emissions [30]. With a rise in the exhaust recirculation to 10%, a higher efficiency is observed in shifting the particle size distribution to larger diameters, recording 41% and 106% for 5 and 10 μm sized particles, respectively. It is also observed that the overall particle emissions are increased. With an exhaust recirculation at 20%, with acoustics at 21 kHz, overall reduction in particle distribution is observed. At higher loads, the particle size distribution is found to be more inclined towards large-sized particles. This signifies that the smaller particles collided to form larger-sized particles. For diesel fuel at 90 Nm, a consistent reduction in small particles and increase in large-sized particles are observed and this tendency is intensified with rise in the exhaust recirculation rate, as shown in Figure 8b. At exhaust recirculate at 10%, 5 μm sized particles are up by 30% and 10 μm particles by 35%. When the recirculation is increased to 20%, the increase in particles is observed to be 54% and 12%.
There is a variation in other emissions in the presence of acoustics, but the changes are either too small to consider or do not follow a specific pattern. However, the influence of acoustics on particle emissions from RME is significant. In contradiction to what was observed for diesel, RME100 is observed to have the highest agglomeration at lower loads and no exhaust recirculation. The combination of the increase in large-sized particles with the reduction in small-sized particles proves that the particles collide with the presence of acoustics and are agglomerated. The particles of 5 μm size increase by 100% and 10 μm sized particles increase by 20%, as shown in Figure 9b. RME have a higher chance of particle agglomeration at lower engine load due to lean mixture combustion [43].
When the exhaust recirculation is increased to 10%, large-sized particles (above 5 μm) are increased at an average of 37%. When the recirculation is further increased by 10% to 20%, particles of a size less than 5 μm are decreased to half and 10 μm sized particles are increased by 30%. At a higher load and with no recirculation, particles across all the six measured sizes are found to decrease, as shown in Figure 10b.
Overall, with acoustics, a noticeable reduction in carbon monoxide and nitrogen oxide is observed. The combined impact of increasing the EGR rate and acoustics is found to have a shift in particle size distribution of diesel fuel. This change is consistent across both loads and all three EGR rates. For RME, the combined impact is found to be effective in higher loads and 10% EGR rate.

4. Discussion

These research results address the challenge of effectively reducing overall emissions (NOX, CO, and particles) without having a negative influence on each other. EGR has proven to lower NOX emissions but has a contradictory influence on carbon monoxide and particle emissions due to the lack of O2 availability. Reducing the combustion chamber temperature can also have an indirect impact on the formation of particles. When an oxygen-rich alternative fuel is included, CO emissions are reduced, and by inducing acoustic waves, better particle filtration is achieved through conventional DPFs that filter particles with comparatively large diameters.
For diesel fuel, with an increase in load, CO is observed to rise due to the air–fuel mixture. A considerable increase in CO emissions is also observed at higher exhaust recirculation rates, which is associated with the reduction in available oxygen. At lower loads, with an increase in EGR from 0 to 10% and from 10 to 20%, O2 decreases by 3 and 14%. The reduction is found to be 9 and 10% at higher loads. As expected, at higher loads, NOX emissions, which are dominated by NO emissions, are found to decrease to an average of 13% for every 10% increase in the EGR rate. A notable decrease in NO2 emissions is observed at lower loads for diesel fuel. These reductions are driven by the reduction in temperature of the combustion chamber due to EGR. At lower loads and higher recirculation rates, there is a shift in particle size distribution to larger diameters as a result of the quality of the air–fuel mixture.
By introducing an oxygen-rich alternative fuel with LHV, there is an average reduction of 30% of CO emissions at both loads attributed to the complete oxidation of the fuel during combustion. A slight reduction in NOX emissions is observed at higher loads due to its shorter ignition delay, but the emissions are further increased at lower loads as oxygen influences the combustion temperature. The NOX emissions of RME have an impact on the EGR rate similar to that observed for diesel fuel. The reduction in NO emissions is at an average of 6% for every 10% increase in the EGR rate. In comparison to D100, this reduction in rate is primarily due to the oxygen content of the fuel. The shift in particle size distribution at lower loads continues to follow the pattern exhibited by diesel fuel. At lower loads, reduction in fine particles (size < 2.5 μm) is observed with a rise in the exhaust recirculation rate, and particles with sizes 5 and 10 μm are found to decrease at higher loads.
The impact of acoustic waves on particle emissions is one of the most efficient ways to tackle fine particles. For D100 at 10% EGR, the shift in particle size distribution to higher sized particles is much more effective with 41% and 106% for 5 and 10 μm particles, respectively, at lower loads, and 30% and 35%, respectively, at higher loads. The change is also observed at higher EGR rates. There is a considerable reduction in CO emissions at higher EGR rates in both loads. No consistent pattern is observed in any of the other emission changes with acoustic waves. At a lower load and EGR rate, when RME is used, the particles of size 5 μm are doubled and 10 μm sized particles are increased by 20%. Along with a noticeable reduction in particles of a size less than 1 μm, 5–10 μm sized particles are increased by 37%.
Largely, for both diesel and RME, a uniform reduction in particles less than 2.5 μm and shift of particle distribution to larger diameters (>2.5 μm) is observed at the exhaust recirculation rate of 10%. With an increase in the exhaust recirculation rate to 20%, the air–fuel mixture is diluted with the carbon dioxide and water present in the recirculated gas, which contributed to incomplete oxidation of the fuel.

5. Conclusions

The emissions of IC engine powered with D100 and RME100 fuels are analyzed at a lower load of 60 Nm and a higher load of 90 Nm to study the influence of EGR at three different rates (0, 10 and 20%), along with the impact of acoustic waves at 21 kHz and 140 dB.
For both fuels, CO emissions increase with the exhaust recirculation rate, as a result of reduced oxygen availability. For D100, at 20% EGR, at a lower load, the emissions are increased by 62%, and 103% for a higher tested load. This is found to be 62 and 21% for RME100.
For every 10% increase in the exhaust recirculation, nitrogen oxide emissions are observed to decrease to an average of 6% at 90 Nm and 4% at 60 Nm for both tested fuels.
At lower EGR rates and higher loads, D100 produces higher NOX and CO emissions. RME100 provides better combustion properties, but the oxygen-rich nature of the fuel negatively influences NOX emissions, especially when the EGR benefits are overcompensated by the oxygen content. The EGR rate effectively reduces NOX but increases CO emissions as the air intake mass flow rate is reduced with a rise in exhaust recirculation, thereby decreasing the purity of the air–fuel mixture, resulting in higher CO emissions.
It is observed that to obtain the highest combining impact with acoustics, EGR is to be moderate (10% in this research). Diesel is found to have a significant impact on both loads, but RME has a higher chance of particle agglomeration at lower engine loads due to lean mixture combustion.

Author Contributions

Conceptualization, S.M.R.; methodology, J.M.; software, S.M.R. and J.M.; validation, S.M.R. and J.M.; formal analysis, S.M.R. and J.M.; investigation, S.M.R.; data curation, S.M.R.; writing—original draft preparation, S.M.R.; writing—review and editing, S.M.R.; project administration, J.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Schematic representation of engine and acoustic setup: 1-Mass Air Flow Sensor; 2-Turbocharger; 3-Air Pressure Meter; 4-Air Cooler; 5-Temperature sensor; 6-Exhaust Gas Recirculation Valve; 7-Exhaust Gas Temperature Meter; 8-Intake Gas Temperature Meter; 9-Cylinder Pressure Sensor; 10-Fuel Injection Timing Sensor; 11-Exhaust Gas Analyser; 12-Smoke Analyser; 13-Fuel Tank; 14-Fuel Consumption Calculation Equipment; 15-Fuel Pump Crankshaft; 16-Position Sensor; 17-Electronic Control Unit; 18-Fuel Injection Moment Recording Equipment; 19-Torque and Speed Measurement; 20-Engine Load Plate; 21-Cylinder Pressure Recording Equipment; 22-Connecting Shaft; 23-Acoustic setup (Red lines indicate acoustic waves, black lines indicate the flow of exhaust gases).
Figure 1. Schematic representation of engine and acoustic setup: 1-Mass Air Flow Sensor; 2-Turbocharger; 3-Air Pressure Meter; 4-Air Cooler; 5-Temperature sensor; 6-Exhaust Gas Recirculation Valve; 7-Exhaust Gas Temperature Meter; 8-Intake Gas Temperature Meter; 9-Cylinder Pressure Sensor; 10-Fuel Injection Timing Sensor; 11-Exhaust Gas Analyser; 12-Smoke Analyser; 13-Fuel Tank; 14-Fuel Consumption Calculation Equipment; 15-Fuel Pump Crankshaft; 16-Position Sensor; 17-Electronic Control Unit; 18-Fuel Injection Moment Recording Equipment; 19-Torque and Speed Measurement; 20-Engine Load Plate; 21-Cylinder Pressure Recording Equipment; 22-Connecting Shaft; 23-Acoustic setup (Red lines indicate acoustic waves, black lines indicate the flow of exhaust gases).
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Figure 2. Acoustic housing setup.
Figure 2. Acoustic housing setup.
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Figure 3. Emissions of diesel at 60 Nm load: (a) Other emissions; (b) PN emissions.
Figure 3. Emissions of diesel at 60 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 4. Emissions of diesel at 90 Nm load: (a) Other emissions; (b) PN emissions.
Figure 4. Emissions of diesel at 90 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 5. Emissions of RME at 60 Nm load: (a) Other emissions; (b) PN emissions.
Figure 5. Emissions of RME at 60 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 6. Emissions of RME at 90 Nm load: (a) Other emissions; (b) PN emissions.
Figure 6. Emissions of RME at 90 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 7. Impact of acoustic waves on diesel emissions at 60 Nm load: (a) Other emissions; (b) PN emissions.
Figure 7. Impact of acoustic waves on diesel emissions at 60 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 8. Impact of acoustic waves on diesel emissions at 90 Nm load: (a) Other emissions; (b) PN emissions.
Figure 8. Impact of acoustic waves on diesel emissions at 90 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 9. Impact of acoustic waves on RME emissions at 60 Nm load: (a) Other emissions; (b) PN emissions.
Figure 9. Impact of acoustic waves on RME emissions at 60 Nm load: (a) Other emissions; (b) PN emissions.
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Figure 10. Impact of acoustic waves on RME emissions at 90 Nm load: (a) Other emissions; (b) PN emissions.
Figure 10. Impact of acoustic waves on RME emissions at 90 Nm load: (a) Other emissions; (b) PN emissions.
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Table 1. D100, RME100 fuel properties.
Table 1. D100, RME100 fuel properties.
PropertiesD100RME100
Density (kg/m3)843877
Mass fraction (% mass): carbon86.377.5
Hydrogen13.712
Oxygen010.5
C/H6.306.46
Lower heating value (LHV) (MJ/kg)42.337.8
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MDPI and ACS Style

Rayapureddy, S.M.; Matijošius, J. Influence of EGR and Acoustic Waves on Particles and Other Emissions of IC Engine Powered with Diesel and RME Fuels. Fuels 2025, 6, 67. https://doi.org/10.3390/fuels6030067

AMA Style

Rayapureddy SM, Matijošius J. Influence of EGR and Acoustic Waves on Particles and Other Emissions of IC Engine Powered with Diesel and RME Fuels. Fuels. 2025; 6(3):67. https://doi.org/10.3390/fuels6030067

Chicago/Turabian Style

Rayapureddy, Sai Manoj, and Jonas Matijošius. 2025. "Influence of EGR and Acoustic Waves on Particles and Other Emissions of IC Engine Powered with Diesel and RME Fuels" Fuels 6, no. 3: 67. https://doi.org/10.3390/fuels6030067

APA Style

Rayapureddy, S. M., & Matijošius, J. (2025). Influence of EGR and Acoustic Waves on Particles and Other Emissions of IC Engine Powered with Diesel and RME Fuels. Fuels, 6(3), 67. https://doi.org/10.3390/fuels6030067

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