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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Influence of Fuel-Rich Combustion on the Accuracy of Turbine Speed Prediction in the Event of Shaft Failure</title>
      <link>https://trid.trb.org/View/2598422</link>
      <description><![CDATA[A physics-based component-level model has been developed to investigate the influence of fuel-rich combustion on the accuracy of low-pressure turbine speed prediction following low-pressure shaft failure in a turbofan engine. The model extends turbine performance characteristics into high-speed regime and compressor characteristics beyond the surge line to accurately capture abnormal engine dynamics. Simulation results reveal that low-pressure shaft (LPS) failure induces compressor surge, leading to a sharp drop in core mass flow and a rapid increase in the fuel-air ratio, which triggers a transition from fuel-lean to fuel-rich combustion. The element potential method is employed to compute the gas composition under fuel-rich conditions, showing substantial shifts in gas properties such as specific heat ratio, gas constant and specific heat capacity. This changes significantly affects the expansion process, thereby influencing low-pressure turbine (LPT) behavior. Quantitatively, fuel-rich combustion increases the turbine power output and angular acceleration, enabling the LPT to reach burst speed up to 6.4% faster compared with conventional models. The proposed component-level model (CLM), incorporating a combustor model that accounts for fuel-rich effects, offers improved fidelity in LPT overspeed prediction and provides valuable insights for engine safety analysis under shaft failure scenarios.]]></description>
      <pubDate>Wed, 11 Mar 2026 14:44:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2598422</guid>
    </item>
    <item>
      <title>Development of Automatic Calibration System for PFI Engines</title>
      <link>https://trid.trb.org/View/2623946</link>
      <description><![CDATA[This report summarizes the research findings on fuel injection calibration methods, aiming to improve engine performance and reduce environmental impact. In Port Fuel Injection (PFI) engines, the injected fuel adheres to the port walls and mixes with air as it vaporizes, then flows into the combustion chamber. Traditionally, the fuel injection quantity is determined by the base map, which is calibrated for a steady state, and corrections for transient conditions. During steady-state operation, the air-fuel ratio of the mixture is uniquely determined by the amount of fuel injected, allowing for reproducible calibration. However, during transient conditions, the amount of fuel adhering to the walls and the amount vaporized do not balance, necessitating transient compensation to achieve the desired air-fuel ratio. Traditional transient compensation has been adapted for each engine model based on experience to accommodate differences in port shapes and injector placements. This approach has not always resulted in optimal calibration and often required significant time. To address this issue, a new transient compensation logic and an automated calibration system have been developed, enabling efficient and optimal calibration. The implementation of this system eliminates variations due to the skill level of the calibration engineer and reduces time requirements. Furthermore, optimal calibration contributes to improved engine performance and reduced environmental impact.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:05:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2623946</guid>
    </item>
    <item>
      <title>Transient Helium Jet Evolution Using High Speed Schlieren Imaging</title>
      <link>https://trid.trb.org/View/2623927</link>
      <description><![CDATA[The accelerating global shift towards decarbonised energy systems has positioned hydrogen as a highly promising carbon-free fuel. This study comprehensively investigates the macroscopic characteristics and temporal evolution of vortex ring trailing helium jets, serving as a surrogate for hydrogen, injected into a quiescent ambient environment using high-speed Schlieren imaging. This research addresses critical insights into fuel-air mixing dynamics essential for optimising hydrogen direct injection (DI) internal combustion engines. Analysis of helium jet tip’s topology revealed a three-stage evolution from an initial pressure-insensitive phase, dominated by pressure wave structures, to a momentum-driven, vortex-dependent growth stage, then to a fully developed stage. Specifically, the lower-pressure cases showed increased Kelvin-Helmholtz instability and distinct head vortex pinch-off at the final stage. Jet tip velocities transitioned from initial high, rapid pressure wave development speeds to a momentum-controlled phase, with lower-pressure jets exhibiting greater fluctuations and susceptibility to Kelvin-Helmholtz instabilities effects. Jet width growth initially mirrored across pressures due to vortex ring expansion before diverging into a turbulent mixing regime, notably displaying a transient width reduction as internal ring structures dissipated. The jet angle stabilised around 32°, with higher injection pressures resulting in slightly narrower angles due to enhanced axial momentum. Overall, jet area growth was significantly faster and larger at higher injection pressures, confirming their superior mixing potential. These findings provide crucial insights into the interplay of injection parameters, vortex dynamics, and turbulent processes, advancing the fundamental understanding necessary for optimising fuel-air mixture formation and combustion efficiency in hydrogen DI engine development.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:05:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2623927</guid>
    </item>
    <item>
      <title>Effect of in-cylinder heat transfer and surface temperatures on knock in an SI engine</title>
      <link>https://trid.trb.org/View/2601713</link>
      <description><![CDATA[A single-cylinder, four-stroke, spark-ignition research engine instrumented with heat flux probes in the cylinder head, cylinder liner and piston was tested at two engine speeds and two loads to analyze the effect of in-cylinder heat transfer and surface temperatures on engine knock. During the intake stroke and part of the compression stroke the metal temperature is higher than the charge temperature. Heat transfer from the metal to the air-fuel mixture increases the temperature of the charge resulting in higher end gas temperatures, which can exacerbate knock. In the initial phase of testing, the heat transfer and surface temperatures were varied by changing oil temperature, coolant temperature, and coolant flow rate. In the second phase of testing, individual cycles from the same operating condition were binned according to their knock levels and correlations with the heat transfer before the occurrence of knock were analyzed. The results showed that in-cylinder heat transfer is not a dominant factor impacting engine knock, but an increase in surface temperatures does increase knock intensity. The results also confirmed that knock has a significant impact on the heat transfer that occurs from the gas to the metal after knock onset.]]></description>
      <pubDate>Mon, 24 Nov 2025 10:24:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2601713</guid>
    </item>
    <item>
      <title>In- and near-nozzle and external flow characterization in Gasoline Direct injection (GDi) engines – A review of latest technologies and trends. Part 2: Computational background</title>
      <link>https://trid.trb.org/View/2578901</link>
      <description><![CDATA[In an era where engine design has been influenced by the interest in emissions reduction, the use of gasoline direct injection systems has proven to be an effective means to approach this goal, enhancing the efficiency of these engines. This objective has led researchers to explore new technologies, greatly branching out research in the injection process, especially those that use fuel as one of their energy sources. Gasoline direct injection is now being combined with many other techniques with the aim of increasing efficiency. The use of fuel blends, such as the combination of gasoline with biofuels, hydrogen, compressed natural gas (CNG), and others, holds significant potential to reduce emissions in the transportation sector. These blends enable a transition to cleaner and more sustainable energy sources. However, the mechanics applied, not only to the combination of various technologies but solely to gasoline, have not yet been fully understood. This is largely due to, for example, the relative novelty of this technology compared to its diesel counterparts. The study of the gasoline direct injection processes is essential for the transition to cleaner and more efficient vehicles. Despite the importance of alternative fuels, a thorough understanding of gasoline is crucial for advancing toward more sustainable mobility. Therefore, it has been considered of interest to summarize in this article the latest research topics related to the gasoline direct injection (GDI) process, providing researchers with a valuable resource to understand the current state of research, the different technologies of gasoline direct injection and the phenomena that take place in this process. Since research applied to gasoline direct injection systems is extensive, this article proposes to make a distinction between the injection process and combustion, focusing solely on the injection. In the same way, it is suggested to study the injection process in several phases: in- and near-field of the injector and downstream of the injector. In this study, an extensive analysis is conducted on the CFD techniques employed in recent research. In the same way as Part 1 of this article, which is dedicated to experimental techniques, the goal is to promote a better understanding of the gasoline direct injection processes. In Part 2, this objective is achieved through the study of computational techniques, focusing solely on the injection and mixture formation process.]]></description>
      <pubDate>Fri, 26 Sep 2025 13:39:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2578901</guid>
    </item>
    <item>
      <title>Experimental analysis on the impacts of engine-out lambda frequency and amplitude on three-way catalyst performances</title>
      <link>https://trid.trb.org/View/2578897</link>
      <description><![CDATA[The hybrid powertrain with an advanced three-way catalyst (TWC) can contribute to the decarbonization of current gasoline engine-powered vehicles. Compact TWCs are used in next-generation hybrid electric vehicles (HEVs) to make room for a bigger battery. However, performances of a compact TWC deteriorate under dynamic excess air ratio (lambda λ). Lambda perturbation (dithering or rich-lean cycling) is a technique to improve transient TWC performance. The TWC conversion rate under dynamic lambda perturbation has not been well understood in real engine experiments. This work experimentally investigates the impact of lambda perturbation (frequency f and amplitude A) using an actual engine test. The experiments are performed using a mass-production 4-cylinder, 2.4 L gasoline engine equipped with a modified TWC reactor. THC, CO, and NO conversion rates are investigated under f = 0–1.0 Hz, A = 0–0.1, and exhaust gas temperatures T = 270–350°C. The results show that NO, THC, and CO conversion rates are low for T = 270°C for all frequencies and amplitudes. NO conversion rate is improved at A ≥ 0.04 under various f and T. THC conversion rate over 80% can be obtained under T = 350°C, while CO conversion rate is nearly 100% at T = 350°C for A = 0.02–0.08 and all frequencies. The impact of λ frequency and amplitude on the oxidation reaction rate of CO, NO, and THC are also discussed.]]></description>
      <pubDate>Fri, 26 Sep 2025 13:39:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2578897</guid>
    </item>
    <item>
      <title>Thermoelectric coupling study of scavenging pressure effect on fuel spray and mixing of a vibratory combustion linear engine</title>
      <link>https://trid.trb.org/View/2586823</link>
      <description><![CDATA[The vibratory combustion linear engine is a promising energy converter that transforms thermal energy from fuel combustion into electrical energy through mechanical vibration. However, the effect of scavenging pressure on fuel spray and mixture formation under complex coupling conditions remains underexplored. To address this, a thermoelectric coupling model was developed to simulate the impact of scavenging pressure on mixture formation by integrating vibration, scavenging, power generation, and combustion, then updates the computational results of vibration and combustion calculations with an iterative algorithm to accurately simulate the effect of scavenging pressure on the mixture formation characteristics. Results show that scavenging pressure affects engine vibration, compression ratio, and fuel injection conditions. At a scavenging pressure of 1.1 bar, the fuel evaporation rate is 98.98%, the mixing uniformity index is 58.12%, and turbulence kinetic energy is 7.11 m²/s². As scavenging pressure increases, the mixing uniformity decreases. Meanwhile, turbulence kinetic energy and fuel evaporation rate initially increase and reach their peak around 1.4 bar, after which they begin to decrease due to increased resistance to the fuel spray at higher pressures. Increased scavenging pressure enhances airflow momentum, improving atomization and spray penetration, while prolonging ignition delay. This delay provides more time for atomization, evaporation, and mixing before combustion, ultimately improving mixture quality.]]></description>
      <pubDate>Fri, 26 Sep 2025 13:39:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2586823</guid>
    </item>
    <item>
      <title>Predicting Fuel Properties and Emissions for Advanced Biofuels for Diesel Engines: Cooperative Research and Development Final Report, CRADA Number: CRD-18-00765: Project 5</title>
      <link>https://trid.trb.org/View/2589137</link>
      <description><![CDATA[The project will investigate variations in biofuel composition and optimize performance in combustion for conventional and future compression ignition engines. It will evaluate a variety of bio-derived molecules in the diesel range that can be produced using technology in ExxonMobil’s portfolio as well as fuels that cover the range of potential molecular structures for robust model development. Changes in fuel/air premixing and stratification in advanced engines could alter the relationship between fuel properties and performance in comparison to current-generation spray combustion approaches. The National Renewable Energy Laboratory's (NREL’s) experience in fuel and combustion modeling will enable the development of general rules for predicting the performance of a wide range of biofuel options. This final report includes a summary of the research results.]]></description>
      <pubDate>Mon, 08 Sep 2025 14:53:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2589137</guid>
    </item>
    <item>
      <title>Optical study on the single and multiple regions of flame propagation and combustion characteristics of methane/air mixture ignited by pilot diesel</title>
      <link>https://trid.trb.org/View/2570818</link>
      <description><![CDATA[The combustion characteristics of lean methane/air mixtures ignited by single and multiple diesel sprays were investigated using an optical RCEM test bench. The experimental approach included flame natural luminescence photography, pressure data acquisition, and heat release analysis. The results revealed that the relationships of ignition delay and orifice diameter varied under single diesel and dual fuel combustion mode. Under dual fuel mode, increasing the orifice diameter of the single-orifice nozzle resulted in a reduction in ignition delay, an acceleration in flame propagation, and an increase in the heat release rate. Increasing the number of orifices multiplied the flame regions, expanded the flame propagation pathways, and enhanced the promoting effect between the flames, resulting in faster flame propagation and increased heat release. The orifice axis angle significantly affected the ignition position and flame propagation direction. An appropriate axis angle would shorten the flame propagation distance, optimize the flame propagation direction and mitigate the impediment effect between flames.]]></description>
      <pubDate>Fri, 18 Jul 2025 09:05:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2570818</guid>
    </item>
    <item>
      <title>Numerical investigation of ducted fuel injection using Multiple Representative Interactive Linear Eddy Model</title>
      <link>https://trid.trb.org/View/2552338</link>
      <description><![CDATA[Fuel-air mixing in non-premixed and partially premixed combustion has a major influence on soot emissions. Improving the mixing quality of the premixed region in non-premixed combustion upstream of the auto-ignition zone aids substantially in reducing soot emissions. The Ducted Fuel Injection (DFI) concept is based on injecting fuel inside a metal cylinder inside the combustion chamber at a certain distance from the injection nozzle exit hole. Although the concept is straightforward, recent studies have shown that implementing DFI in compression ignition combustion chambers dramatically affects soot mitigation. DFI improves air entrainment by a suction effect when fuel travels inside the duct, which increases the turbulence level at the inlet and enhances the fuel-air mixing quality. Additionally, DFI delays ignition by preventing the formation of stoichiometric regions at the spray cone’s outer region. This work utilizes a recently presented combustion model titled the Multiple Representative Interactive Linear Eddy Model (MRILEM) to simulate DFI in a high-pressure, high-temperature constant volume chamber. Several simulations are realized for two different ambient temperatures using an n-dodecane mechanism, where several parameters, such as ignition delay, lift-off length, and flame structure, are assessed. Simulation results are compared to experimental data from the literature and simulation results obtained with the Multi-Zone Well Mixed (MZWM) model simulation results. Results show that by enforcing the duct on the LEM line and modifying the turbulence implementation strategy, MRILEM shows overall realistic predictions for DFI cases and reasonable quantitative results for lift-off length and ignition delay compared to the MZWM model.]]></description>
      <pubDate>Tue, 17 Jun 2025 09:58:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2552338</guid>
    </item>
    <item>
      <title>Applications of machine learning techniques to broaden operating envelope of biodiesel-fueled HCCI engines</title>
      <link>https://trid.trb.org/View/2552333</link>
      <description><![CDATA[A significant shortcoming of Homogeneous charge compression ignition (HCCI) engines is their narrow operating envelope, particularly with high-reactivity fuels like biodiesel. Additionally, the compositional variability of biodiesels, reflected in cetane number variations based on different source feedstocks, poses another challenge. While various strategies have successfully extended the maximum load limit in diesel-HCCI engines, they have not been adequately explored in biodiesel-fueled HCCI engines. This study is the first to comprehensively investigate the interplay of biodiesel composition, cetane number, engine compression ratio, and charge dilution strategy for extending the operating envelope of a light-duty HCCI engine. Given the impracticality of controlling multiple variables experimentally, this work focuses on the potential of machine learning (ML) algorithms to predict the operational limits of an HCCI engine using neat biodiesels derived from diverse sources. Among the ML models explored, artificial neural networks were the most accurate in predicting the minimum stable load, with prediction errors of 3.5% (calibration) and 3.9% (validation). Support vector machine models predicted the maximum load (with and without dilution) with errors below 5%. Notably, biodiesel produced from a blend of linseed, karanja, coconut, and mustard oils in specific proportions (42%, 3%, 25%, and 30% mass, respectively) yielded a wide HCCI operating range from 0.4 to 3.25 bar (without dilution) and up to 3.67 bar BMEP with charge dilution. This study highlights the novelty and practicality of using ML to predict and extend the operating envelope for biodiesel-fueled HCCI engines, demonstrating their suitability for future applications.]]></description>
      <pubDate>Tue, 17 Jun 2025 09:58:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2552333</guid>
    </item>
    <item>
      <title>Computational investigation of a methanol compression ignition engine assisted by a glow plug</title>
      <link>https://trid.trb.org/View/2521694</link>
      <description><![CDATA[This work explores the feasibility of pure methanol combustion in a light-duty diesel engine assisted by a glow plug (GP). The simulations represented a mild engine load with an indicated mean effective pressure of 7 bar. An extensive computational study was conducted, and the successful operation of the pure methanol compression ignition engine was demonstrated. The effects of the GP position, spray umbrella angle, the relative angle (RA) between the glow plug and jet trajectory, and the injection strategy on the engine performance were evaluated. The autoignition of methanol-air mixture was found to primarily occur at an equivalence ratio between 0.2 and 0.4. However, an even richer mixture accompanied the lower temperature due to intense heat absorption of evaporation, significantly prolonging the ignition delay. Therefore, to improve the ignition and combustion heat release processes, RA was optimized to adequately control the mixture distribution around the GP. At each position of the GP, the optimum RA differed due to the complex flow and air-fuel mixing within the combustion chamber, which became smaller (from 12.5° to 5°) when the GP was moved anticlockwise from the intake port to the exhaust port regions. Furthermore, a split injection strategy was proposed to ensure the successful ignition of the methanol jets. The engine performance exhibited a high sensitivity to the pilot and main injection timings. A small pilot mass fraction of no higher than 20% was recommended to mitigate fuel jet-GP interaction and fuel impingement in the squish region.]]></description>
      <pubDate>Wed, 28 May 2025 10:12:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/2521694</guid>
    </item>
    <item>
      <title>Novel direct injection electro-hydraulic model-based controller for high efficiency internal combustion engines</title>
      <link>https://trid.trb.org/View/2518195</link>
      <description><![CDATA[During the past years, automotive industries developed several technologies suitable to increase efficiency and reduce emissions from Internal Combustion Engines (ICEs). Among them, the adoption of high-pressure injection systems is considered crucial to optimize air-fuel mixture formation. However, the use of these technologies also promotes the formation of particulate matter (PM Particulate Matter), which is a direct result of charge stratification and fluid film on the cylinder walls. Therefore, to obtain a proper mixture formation without the risk of wall impingement, the utilization of consecutive injections is mandatory. Since modern Gasoline Direct Injection (GDI) systems are typically characterized by electrical-actuated injectors connected to a single high-pressure rail, a deep understanding of electrical and hydraulic effects among two close injection events becomes essential. This paper analyzes the combinations of electrical and hydraulic effects that occur in a high-pressure GDI system performing multiple injections. By using a specifically developed open vessel flushing bench, the injection system has been characterized in terms of pressure wave propagation as well as electrical distortions of the driving current profile of the injectors. The analysis of the experimental data has allowed for the calibration of the residual magnetization characteristic map in addition to the development of a pressure wave propagation control-oriented model. Finally, a Magnetization and Pressure Wave (MPW) correction strategy, easily implementable on an Electronic Control Unit (ECU) without the need for additional sensors, has been proposed. By running the MPW strategy, the error between the actual and expected injected mass has been reduced below 5% in all tested conditions.]]></description>
      <pubDate>Fri, 23 May 2025 15:34:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2518195</guid>
    </item>
    <item>
      <title>A consistent model of the initiation, early expansion, and possible extinction of a spark-ignited flame kernel</title>
      <link>https://trid.trb.org/View/2518188</link>
      <description><![CDATA[Modelling the establishment and growth of spark-ignited (SI) flame kernels has always been a topic of great interest, especially due to their key role in affecting the performance of SI engines. A major issue is that the unsteady conditions and the small kernel size hinder the application of the typical (both linear and non-linear) flame stretch correlations, valid only long after the ignition stage. Overcoming such limitations, this work presents a novel, mathematically consistent, and compact model that enables prediction of flame kernel initiation and early expansion, including its possible extinction. Firstly, spark-driven initiation models from literature are discussed, and an effective flame kernel initiation method is proposed. Then, the expansion model is defined complementing the mass, energy, and species conservation equations for the spherical kernel with the reactant and temperature profiles outside of it using the theory of transient thermodiffusive flames. After accounting for the convective flow caused by the combustion-induced density reduction and the variable thermodynamic properties of the reacting fuel/air mixture, the result is a two-equation model that predicts the kernel expansion even up to its possible extinction due to flame stretch. After calibration of the expansion model, successful validation is achieved against literature data on lean propane/air flames, and the influence of the model parameters is examined in detail. The proposed expansion model is formulated also aiming for inclusion into the simulation of combustion in SI engines, enabling more accurate predictions at part loads, as well as more effective estimation of the cycle-to-cycle variation thanks to the good model sensitivity to the parameters most affecting the ignition.]]></description>
      <pubDate>Fri, 23 May 2025 15:34:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2518188</guid>
    </item>
    <item>
      <title>Turbocharged DISI engine low-load performance improvement investigation through ozone seeding with residual gases and excess air charge dilution</title>
      <link>https://trid.trb.org/View/2536207</link>
      <description><![CDATA[The automotive industry has long prioritized the search for more efficient engines, driven by environmental concerns, fuel prices, and consumer demand for fuel-efficient vehicles. Various technologies and strategies are explored to enhance performance while reducing fuel consumption and emissions. Despite potential combustion stability issues, techniques like using lean mixtures or retaining exhaust gases are commonly employed. Ozone seeding has emerged as a combustion enhancer for internal combustion engines, particularly effective under lean mixtures or high residual gas levels, aiming to stabilize de-throttling conditions, minimize pumping losses, and enhance engine efficiency by enhancing the reactivity of the mixture through the release of radicals that facilitate fuel oxidation. This study investigates the impact of ozone addition on engine performance, emissions, and fuel consumption using a turbocharged SI vehicular engine on a dynamometer bench under different loads. Ozone was introduced to the engine intake using an ozone generator with compressed air, considering two mixture dilution strategies: fresh air and residual gases. Results show that ozone application, with Brazilian Gasoline Type C, induces autoignition of the end-gas under specific low-load, low-engine speed conditions. Up to 1000 ppm, ozone has no discernible impact on DISI engine operation under excess air dilution, maintaining performance equivalent to the baseline. For specific operating conditions with 3 and 4 bar BMEP, where ozone stabilizes combustion with higher residual gas fraction (RGF) percentages, there is a notable reduction in specific fuel consumption, suggesting a potential 1%–1.5% increase in brake efficiency. However, ozone seeding with high RGF percentages leads to a slight increase in CO emissions, elevated NOₓ emissions, and a tendency to reduce THC emissions up to a certain RGF limit.]]></description>
      <pubDate>Fri, 25 Apr 2025 16:12:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2536207</guid>
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