The acoustic performance of seven vehicles was evaluated according to Canadian Motor Vehicle Safety Standard 141 (CMVSS 141), which governs minimum required sound levels for hybrid and electric vehicles with a gross vehicle weight rating (GVWR) of 4536 kg (10,000 lb) or less. To better understand the sound profiles of medium-duty electric vehicles (MDEVs) and heavy-duty electric vehicles (HDEVs), the sound emissions of two light-duty electric vehicles (LDEVs), one MDEV, three HDEVs, including an electric transit bus, and one heavy-duty internal combustion engine (HD ICE) vehicle were compared. The sound emissions of the MDEV and HDEVs were quieter than the HD ICE vehicle and comparable to that of the LDEVs equipped with auxiliary speakers. The MDEV with its auxiliary speaker turned off and all three HDEVs without auxiliary speakers met CMVSS 141 requirements in reverse gear and at speeds of 20 km/h and 30 km/h. The MDEV, though not subject to CMVSS 141, failed to meet the minimum sound

Sharma, Vinay, Larocque-Legros, Marc-André, Weston, Cole, Schulte, Andrew, Christenson, Martha, Rooney, Anne

Experimental Analysis of Performance and Durability Using Ethanol 27% Fuel Blend in a Turbocharged Gasoline Direct Injection Engine

2025-01-0245

To be published on 06/16/2025

India aims to achieve 20% ethanol blending (E20) in petrol by 2025 under its National Biofuels Policy to reduce carbon emissions, enhance energy security, and support the agricultural economy. Building on this, E27 (27% ethanol in gasoline) is being evaluated as an advanced mid-level blend to further lower greenhouse gas emissions and reduce reliance on fossil fuels. This study investigates the performance, emissions, and combustion characteristics of a turbocharged gasoline direct injection (TGDI) engine using E27 fuel over 20,000 km in real-world driving conditions, as part of a broader research program accumulating over 100,000 km across multiple vehicle categories. Key findings indicate that E27 achieves an optimal balance of emissions reduction and performance, with NOx and THC emissions decreasing by 12% and 5%, respectively, compared to E10, while CO and CO₂ levels remained stable, reflecting ethanol’s oxygenation effect and lower carbon intensity. Power output and acceleration

D R, Vigneshwar, Bhakthavachalu, Vijayabaskar, Muralidharan, M.

Three-Dimensional CFD Analysis of a Flat Engine Lubrication System

2025-01-0215

To be published on 06/16/2025

This study presents a comprehensive, transient, 3-D Computational Fluid Dynamics (CFD) model of a multi-cylinder flat engine's lubrication system, simulated using Simerics-MP+. Engine lubrication system is crucial for reducing friction, cooling, and cleaning engine components. Understanding its performance is essential for optimal engine operation. The model was applied to the lubrication system of a 4-cylinder, reciprocating internal combustion engine. The computational domain includes the positive displacement gerotor pump, pressure regulation valve, bearings, piston cooling jets, oil cooler, oil filter, and other relevant components. The gerotor pump and gallery bearings were modeled using real 3-D geometries without any assumptions. Bearing deformation and orbiting due to force imbalance were prescribed in the simulations. The simulation was conducted at 5000 rpm of engine speed. The simulated flow pressure distributions closely matched experimental data.

Shiyi, Pan, Nan, Zhang, Jing, Liu, Mingliang, Liu, Wei, Wang

Flame Developments of Pilot Diesel Ignited Hydrogen Jet in an Optical Dual Direct Injection Engine

2025-01-0237

To be published on 06/16/2025

This study aims to characterise the flame development for hydrogen-diesel dual direct injection (H2DDI) in an optically accessible heavy-duty engine through high-speed imaging of the natural combustion luminosity. A single hole, side mounted injector was used to inject H2 at 35 MPa in addition to a centrally mounted eight-hole diesel injector providing the ignition source for the H2. Firstly, the diesel pilot flame was examined without H2 to establish the combustion characteristics of the pilot flame. The pilot fuel energy was reduced from 1200 J to 120 J until the minimum repeatable diesel flame was found, which showed a flame distribution that transitioned from an initial quasi-steady diesel flame at peak load (1200 J), to a piston bowl wall-centric flame distribution (840 J) and then to an injector centric flame (120 J). The minimum pilot fuel quantity of 120 J was then used to investigate the ignition process of hydrogen main fuel mixtures supplying 90% energy and only 10% energy

Heaton, Alastar, Chan, Qing Nian, Kook, Sanghoon

Morphology Experiment of Icing Effect on Spray Propagation

2025-01-0222

To be published on 06/16/2025

The working conditions of combustion systems have been going extreme under the desire of human beings exploring the unknown. Cold environments can be a significant impact on the spraying of fuel not only by changing the fuel properties including viscosity and surface tension, but also by freezing the parts. In the present study, methanol spray from a commercial injector is studied via high-speed imaging, with the liquid fuel being frozen to sub-zero degrees at the injector tip. It is observed that water components from the environment will freeze at the injector tip, creating crystal structures on the surface. During the injection, the ice components will be flushed by the liquid, and the spray morphology of the starting cycle will be strongly altered, resulting in wider spray angles, much shorter penetrations, and particle structures can be observed in the downstream of the flow field. The results of the experiment provide a clear view and quantified evaluation of the freezing impact

Zeng, Tingxi, Wang, Shangning, Zhang, Yijia, Hung, David, Xu, Min

“A Comparative Assessment of Port Fuel Injection and Direct Injection of Hydrogen in Internal Combustion Engines: Performance, Efficiency, and Emissions”

2025-01-0239

To be published on 06/16/2025

With the transition toward low-carbon fuel-based transportation systems, hydrogen is becoming increasingly promising as a sustainable internal combustion engine (ICE) fuel. There are two pathways for introducing hydrogen: Port Fuel Injection (PFI) and Direct Injection (DI) in an engine, which greatly affect performance, efficiency, and emissions. In the Port Fuel Injection (PFI), hydrogen is introduced into the intake manifold and mixed with air before reaching the combustion chamber. This approach is preferred due to its affordability, ease of use, and compatibility with current engine configurations. Because of PFI's more uniform air-fuel mixture, combustion is smoother, and NOx emissions are reduced. On the other hand, it raises the possibility of pre-ignition, particularly when engine loads are high, and a decrease in volumetric efficiency due to a reduction in the volume of intake air as hydrogen replaces it. Direct injection gives exact control over the timing and volume of fuel

Ahirwar, Sachin, Kumar, Naveen

NVH Improvement of Transmission Electric Oil Pump with Uneven Pitch Control

2025-01-0252

To be published on 06/16/2025

This paper proposes an uneven pitch control for electric oil pumps. For the noise reduction of vane pumps, mechanical arrangements of uneven pitch vain angle are widely used. However, the tooth angle of gear-type pumps should be even mechanically. The proposed uneven pitch control provides similar effects of the mechanical uneven pitch arrangement by instantaneous motor torque controls of the electric oil pump which cannot have uneven pitch mechanically. The magnitude of motor torque for each pump tooth is determined by an uneven pitch formula which is widely used for mechanical vane pumps in previous study and patents. A formula for the shape of motor torque is proposed by analyzing pressure fluctuations of pump as a combination of trigonometric and exponential functions. The calibration factors for the magnitude and shape are adjusted by characteristics of pumps. The experimental results showed that noise reduction and dispersion effects of the proposed method.

Choi, Chinchul, Kim, Jongbeom

Comparison of Spark and Turbulent Jet Ignition in a Fully Ammonia-Fueled Engine

2025-01-0201

To be published on 06/16/2025

Ammonia (NH3) is an emerging carbon-free fuel with the potential to decarbonize the energy sector. However, its widespread adoption is hindered by challenges like low flame speed, high ignition energy, elevated emissions of nitrogen oxides (NOx), and unburned NH3. These limitations necessitate innovative combustion strategies for efficient and stable engine operation. This study investigates the potential of turbulent jet ignition (TJI) to overcome these challenges through the implementation of a pre-chamber, a small auxiliary chamber equipped with a spark plug to create hot, reactive jets that propagate into the main chamber, promoting rapid combustion from distributed ignition sites. In this work, TJI operation is compared to conventional spark ignition (SI) in a diesel engine platform retrofitted for 100% ammonia operation. Experiments were conducted at 1200 and 1800 RPM across varying loads (25%, 50%, 75%, and 100%) with equivalence ratio and spark timing sweeps. Combustion

Dhotre, Akash, Voris, Alex, Okey, Nathan, Kane, Seamus, Northrop, William

Effects of Double Injection Strategy in a Diesel-Ammonia Dual-Fuel Engine

2025-01-0206

To be published on 06/16/2025

This study investigates the application of a double injection strategy in a single-cylinder marine diesel-ammonia dual-fuel engine retrofitted for experimental analysis. A diesel micro-pilot (MP) injection was used to ignite ammonia combustion, and diesel and ammonia were injected separately into the cylinder through dedicated injectors. The first MP injection timing was fixed at reference injection timing, and both early and late double MP injection strategies were implemented to evaluate their effects on ammonia combustion, engine performance, and exhaust emissions. Under all conditions, the ammonia injection timing remained constant. Early double injection strategies, with the second MP injection occurring before the first, enhanced premixed diesel combustion by raising in-cylinder temperature and pressure. However, this early heat release was ineffective for ammonia evaporation and combustion due to poor timing alignment. In contrast, late double injection strategies, with the

Park, Chansoo, Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Gyeongtae

Effect of Ignition Condition and Fuel Octane Number on Knock Intensity in a Small 2-Stroke Engine

2025-01-0211

To be published on 06/16/2025

Internal combustion engines (ICEs) remain widely used in automotive transportation for their high energy storage system efficiency and economic benefits. The 4-stroke engine has dominated all other forms to date, because the Otto cycle is relatively simple to understand. However, the significant benefits such as less pumping work and friction, lighter construction of 2-stroke engine, are attractive for applications that prioritize the simplicity and power density as well as meet the emission regulations. The disadvantages of the 2-stroke engine are mainly caused by the lack of sufficient scavenging process. Also, the overlap of the intake and exhaust phases results in charge short-circuiting, more fuel consumption and high unburned hydrocarbon emissions. For these reasons, it is difficult for 2-stroke engines to achieve stoichiometric combustion, making them incompatible with three-way catalyst to control emissions. The residual exhaust gas in the cylinder makes the spark ignition

Liu, Jinru, Yamazaki, Yoshiaki, Otaki, Yusuke, Kato, Hayato, Yokota, Takumi, Iijima, Akira

Residual Gas and Emission Characteristics in a Propane-Fueled Spark-Ignition Engine with Varying Combustion Durations

2025-01-0202

To be published on 06/16/2025

This research investigates the impact of combustion duration on combustion characteristics, emissions, and residual gas in a propane-fueled spark ignition engine under varying engine speeds. Using a two-cylinder V-twin engine and AVL-Boost simulation, experiments were conducted at speeds ranging from 3000 to 8000 rpm with combustion durations between 40° and 80° crank angle. The study integrates simulation and experimental methods to address challenges in measuring residual gas and effective release energy (ERE) under different conditions. Results show that longer combustion durations generally lead to increased residual gas and BSFC, while also influencing peak fire temperature, effective release energy, and emission characteristics. At 3000 rpm, optimal conditions were observed with a peak BMEP of 11.11 bar, torque of 25.01 Nm, power output of 14.87 kW, and a minimum BSFC of 311.43 g/kWh. Longer combustion durations elevated the residual gas, reaching up to 0.946 at 8000 rpm, and

Quach, Nhu Y, Lim, Ocktaeck

Ammonia-Diesel Engines Segmented Modeling Approach and Simplified Combustion model Research

2025-01-0232

To be published on 06/16/2025

Ammonia-diesel dual-fuel engines can effectively reduce greenhouse gas (GHG) emissions. Aiming at the real-time control requirements of ammonia/diesel dual-fuel engines, this study proposes a segmented real-time modeling method and a heat release rate model simplification strategy by linearized heat release rate curves. First, the engine working cycle is divided into three parts: intake and exhaust stage, compression and expansion stage, and combustion process. Different simulation steps and modeling strategies are designed to optimize computational efficiency while maintaining the necessary level of accuracy at each stage. Secondly, based on the calibrated heat release rate (HRR) curves, feature points are extracted to construct a simplified linear heat release model. In the absence of calibration data, the characteristic points of the HRR curves are obtained through interpolation. Compared with the commonly used combustion model, the Wiebe model, the proposed simplified model can

Li, Guangyuan, Chen, Run, Wang, Xinran, Li, Tie, Zheng, Kexiong, Liu, Shaoling, Liu, Yanzhao, Lyu, Xiaodong

Combustion and Emission Characteristics of Marine Ammonia-Diesel Dual Fuel Engine with Micro-Pilot Injector Change

2025-01-0235

To be published on 06/16/2025

Recently, as regulations on greenhouse gas emissions have become stricter, driven by global warming, there is increasing interest in engines utilizing environmentally friendly fuels. In this context, ammonia is attracting attention as a potential alternative to fossil fuels in the future. However, due to its distinct fuel properties compared to conventional fuels, research is being conducted on utilizing diesel as an ignition source for ammonia. In this study, the effects of diesel injector fuel flow rate, and micro-pilot (MP) diesel injection timing on combustion and exhaust emission characteristics were analyzed in a single cylinder 12L marine ammonia-diesel dual-fuel engine. Two types of diesel micro-pilot injectors were tested. The first one was high flow rate micro-pilot injector (HMPI) and the second one was low flow rate micro-pilot injector (LMPI). HMPI injector had 66% more number of fuel injector nozzle hole and 250% larger fuel flow rate. Therefore, HMPI injector could

Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Chansoo, Kim, Yongrae, Park, Gyeongtae, Lee, Jeongwoo

Design and Optimisation of a Passive Pre-Chamber Ignition System for a Heavy-Duty Hydrogen Engine at Lean Conditions

2025-01-0229

To be published on 06/16/2025

Strict regulations and legislation for carbon emissions and pollution from heavy-duty engines are pushing towards carbon-free fuels such as hydrogen as a fuel for internal combustion engines. Moving towards this goal, the engine design needs to fully comply with hydrogen’s unique characteristics to achieve optimum performance and efficiency. One aspect that can potentially improve combustion efficiency and emissions is adopting the pre-chamber ignition strategy in large-bore engines at lean conditions. The pre-chamber is a small cavity, usually 3-6% of the total engine volume, installed on the cylinder head, housing the initial combustion event, which would then inject the turbulent jet into the main chamber via nozzles placed at the bottom of the pre-chamber. This ignition strategy would provide multiple flame fronts into the main chamber, accelerating combustion speed and enhancing engine performance. However, the pre-chamber must be designed specifically for Hydrogen combustion to

Keshtkar, Hossein, Feng, Yizhuo, Zhao, Hua, Wang, Xinyan

Hydrogen Jet Characteristics of an Outward-Opening Injector Based on Schlieren Imaging

2025-01-0228

To be published on 06/16/2025

Hydrogen was considered as a promising carbon-free fuel for future society. The application of hydrogen in internal combustion engines has drawn more and more attention. Jet performance of hydrogen injection plays a crucial role in characteristics of the hydrogen fuelled engines, in terms of mixture preparation, combustion and heat release in cylinder. In this research, an outward-opening injector was developed for hydrogen direct-injection applications. The jet performance was studied using high-speed schlieren imaging in a constant volume chamber and the effects of injection and ambient pressures on jet characteristics were investigated. The results show that, the hydrogen jet exhibits a conical structure in the near-field and overall presents a bell-shaped appearance under relatively low ambient pressure, which differs from the irregular structure under relatively high ambient pressure. The pressure ratio, defined as the ratio of injection pressure to chamber pressure, significantly

Hu, Chaoqun, Hu, Longbiao, Chen, Haie, Li, Liguang, Wu, Zhijun, Deng, Jun

Analysis of Combustion Characteristics of a Small 2-Stroke Opposed Piston Engine Using an Optically Accessible Engine and Numerical Analysis

2025-01-0223

To be published on 06/16/2025

As global warming becomes more serious, decarbonization of internal combustion engines, which emit a large amount of carbon dioxide, is being promoted. It is predicted that many vehicles will still be equipped with engines in 2035, and a variety of powertrains will be required in the future. Therefore, we focused on the opposed-piston engine as an internal combustion engine specialized for power generation applications. The opposed-piston engine is characterized by its light weight due to the absence of a cylinder head, low S/V ratio due to the ultra-long stroke, reduced cooling loss due to the long stroke, and reduced vibration due to the offsetting of the reciprocating inertial forces of the left and right pistons. We believe that the engine for power generation can achieve the required high efficiency operation and vibration reduction. Therefore, in this study, combustion analysis of a two-stroke opposed-piston engine with features of low vibration, high efficiency, and high output

Yamazaki, Yoshiaki, Watanabe, Sou, Okawara, Ikumi, Otaki, Yusuke, Liu, Jinru, Iijima, Akira

A Study on Improving the Methodology for Torque Modeling Using a Virtual Engine Model

2025-01-0204

To be published on 06/16/2025

This study aims to develop an engine torque prediction model using virtual engine simulation data. Accurate torque prediction is essential for minimizing shift shock and ensuring consistent driving performance, particularly in hybrid vehicles where smooth transitions between electric motors and internal combustion engines are necessary. The Engine Control Unit (ECU) uses a physics-based torque prediction model, requiring ignition timing swing data for precise calibration. The virtual engine model, based on 1D gas dynamics, was calibrated using real engine data obtained from a small number of main operating points. The simulation data obtained from the virtual engine model showed a good correlation with the experimental data. By combining large-scale simulation data with limited experimental data, we effectively calibrated the torque prediction model in ECU and confirmed that the calibration results met the development goals. This study demonstrates the potential for efficient engine

Hur, Donghan, Paeng, Jeonghwan, Kim, Kyusup, Chang, Jinseok, Park, Jongil

Sound Granular Synthesis Method for Sc-Fi Sound Quality of Electric Vehicles

2025-01-0253

To be published on 06/16/2025

Since the powertrain systems of electric vehicles (EVs) lack the traditional engine sound, their NVH performance differs from that of conventional fuel-powered vehicles, making the use of active sound design (ASD) systems increasingly common to provide compensatory sound. With the increasing demand for ASD systems, sci-fi sounds are emerging as a design direction to enhance the acoustic feedback of powertrain systems and to elevate the futuristic and immersive driving experience of vehicles. A method for generating sci-fi soundscapes using a granular synthesis algorithm is proposed in this paper. First, based on the designed sci-fi target sound characteristics, a sound grain generation method using the adaptive principal frequency technique is proposed, and the overlap-and-add (OLA) method is employed to synthesize the sound grains. Then, to enhance the sound continuity and smoothness during the sound synthesis process, a method for optimizing a composite cosine window function using a

Liu, Dezhu, Liu, Zhien, Xie, Liping, Lu, Chihua

Investigating Lubricants Base Oils Reactivity in Ammonia Engines via Accelerated Aging

2025-01-0240

To be published on 06/16/2025

As a carbon-free molecule, ammonia is more and more considered as a relevant fuel for long distance and off-road applications. However, this gas has different combustion characteristics compared to conventional fuels, challenging the suitability of lubricants to such engines. In this work, the evolution of lubricants under conditions mimicking ammonia combustion was assessed. Mineral and polyester lubricant base oils were exposed to oxygen, nitrogen oxides, and ammonia in a pressurized reactor under stirring. Oil aliquots were sampled at regular intervals, and characterized using Fourier Transform Infrared Spectroscopy (FTIR), viscosity and total oxygen and nitrogen contents measurements. Exposure to air containing nitrogen oxides resulted in quicker accumulation of oxidation products compared to neat air, for both the mineral and complex polyester base oil. Besides, exposure to gaseous ammonia in air resulted in a slower oxidation rate for both oils, compared to neat air. A global

Doncoeur, Carole, Giarracca, Lucia, Cologon, Perrine, Rousselle, Christine

An Experimental Study on Aqueous Ammonia and Diesel Dual-Fuel Combustion with Ignition Improving Additives in a Compression Ignition Engine

2025-01-0231

To be published on 06/16/2025

Ammonia is a potential vector of renewably produced hydrogen for combustion systems and decarbonisation of transport. However, anhydrous ammonia has health risks and difficult to handle due to its volatility and toxicity. Therefore, a water-based solution of ammonium hydroxide (NH4OH) was proposed to investigate the potential use as a fuel in a compression-ignition engine. Ammonium hydroxide, also referred to as aqueous ammonia, is liquid phase under atmospheric conditions and, therefore, the storage of such a fuel does not require high pressure. Previous work has established that ammonium hydroxide solution could contribute to energy release during co-combustion with fossil diesel. However, the presence of water reduced combustion stability and limited the extent to which aqueous ammonia could displace diesel. In addition, the characteristics of co-combustion and pollutant emissions of burning such a fuel remain less understood. This study therefore explores the potential of using

Han, Yanlin, Hellier, Paul, Schonborn, Alessandro, Ladommatos, Nicos

Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise

2025-01-0251

To be published on 06/16/2025

Engine and powertrain mounts are vital for isolating vibrations and reducing the transmission of Noise, Vibration, and Harshness (NVH) from the engine to the vehicle structure. Despite technological advancements, addressing NVH issues related to tribological factors continues to pose significant challenges in automotive engineering. This study aims to systematically identify and optimize design parameters of engine/powertrain mounts to minimize NVH levels using CAE tools and parametric optimization techniques in Abaqus and Isight, respectively. The purpose of this research is to investigate the correlation between various design parameters of powertrain mounts and their impact on NVH characteristics. Specific attention is focused on noises such as clunking, banging, or thumping that emerge from the engine bay under dynamic conditions like acceleration, braking, or turning. These sounds often occur as the engine moves excessively due to worn mounts, making unintended contact with other

Ganesan, Karthikeyan, Seok, Sang Ho

Effects of Injection and Intake Timing on Atomization and Combustion in a Hybrid Gasoline Direct Injection Optical Engine under the Low-Speed Low-Load Condition

2025-01-0203

To be published on 06/16/2025

With the growing trend of hybridization in modern engines, hybrid gasoline direct injection (GDI) engines are typically designed for high load at BMEP of 6 to 10 bar, low-to-mid speed of 2000 to 3000 rpm to achieve optimal fuel economy. However, these engines inevitably operate under low-speed, low-load conditions, such as during engine startup and low-speed cruising, where insufficient intake air often leads to poor air-fuel mixing and weak turbulence, resulting in suboptimal combustion. Adjusting intake and injection timing presents a simple and effective approach to optimizing the combustion process in hybrid GDI engines. In this study, an optical engine with a combustion system geometry identical to that of an advanced hybrid GDI engine was used. The engine featured a compression ratio of 15.0:1 and was equipped with a variable timing camshaft for intake timing control and an electronically controlled system for injection timing. High-speed color imaging, using transparent pistons

Cui, Mingli, Fu, Jinhong, Man, Xingjia, Nour, Mohamed, Zhang, Weixuan, Li, Xuesong, Xu, Min

Applied Full-Bridge Micro Strain Gauge to High Pressure Sensor for Gasoline Direct Injection/Hybrid System

2025-01-0220

To be published on 06/16/2025

High Pressure Sensors (HPS) are essential for internal combustion engines and hybrid engine systems. High pressure sensor measures the pressure in the Delivery fuel rail Pipe Module (DPM) to allow the Engine Control Unit (ECU) to control the high pressure pump to generate the required fuel pressure. Most high pressure sensors measure the displacement of the metal-diaphragm according to pressure, and are mainly composed of Half-bridge type Micro Electro Mechanical System (MEMS) elements of the piezo-resistive method. This time, we would like to introduce a high pressure sensor that uses a Full-bridge type MEMS structure. This is cheaper than the existing one and can provide higher performance with reliability. However, there are disadvantages of the full-bridge type applied to high pressure sensors. Unlike the Half-bridge method that measures displacement over a wide area, it measures displacement over a narrow area, so it has the disadvantage of weak to external noise due to increased

Lim, SeungGu, Lee, DongYoung, Kim, JungTaek, Shin, MoonSung

Research on Combustion Characteristics of Flash-Boiling Spray in Cylinders Based on Machine Learning Methods

2025-01-0205

To be published on 06/16/2025

With the increasing number of vehicles in operation, exhaust emissions from engines have exerted negative impacts on ecological environments, prompting researchers to actively pursue cleaner and more efficient in-cylinder combustion strategies. Flash-boiling spray technology, capable of generating superior fuel atomization under relatively low injection pressures, has emerged as a promising approach for achieving performance breakthroughs in gasoline direct injection (GDI) engines. While current research primarily focuses on morphological characterization and mechanistic analysis of flash-boiling spray, there remains insufficient understanding of flame development characteristics under flash boiling spray conditions within engine cylinders. This study systematically investigates the combustion characteristics of TPRF and PRF fuels under both subcooled and flash-boiling spray conditions through the integration of image processing and machine learning methodologies. Experimental

Zhang, Weixuan, Shahbaz, Muhammad, Cui, Mingli, Li, Xuesong, Xu, Min

Commercial Vehicle’s Exhaust Front Pipe Reliability Improvement through Virtual Simulation and Experimental Validation

2025-01-0209

To be published on 06/16/2025

The exhaust front pipe is a critical structural component in commercial vehicles, ensuring the leak-proof flow of exhaust gases into the exhaust after-treatment system while withstanding engine and frame vibrations. To isolate these vibrations, the front pipe is equipped with a flex connector capable of enduring various displacements at frequencies between 8-25 Hz. The position of the flex connector relative to the engine crank axis significantly impacts its structural reliability over its service life. This paper compares the existing design, which features a horizontally positioned flex connector, with a modified design that positions the flex connector vertically and changes the material from SS-304 to SS-321. Finite element analysis was conducted using Nastran software. The fatigue life of the existing flex connector design is approximately 1015 cycles. In contrast, the improved design demonstrates a fatigue life of 1727 cycles, representing a 70% increase in durability compared to

Chandel, Kushal, Paroche, Sonu, Namdev, Akhilesh, Jain, Shailendra, Patil, Keyur

Higher Content n-Butanol Blending Ratios in Diesel Fuel Spray and Combustion Characteristics: Addressing Oxygenated Fuel Challenges with Spark-Assisted Combustion Strategies

2025-01-0210

To be published on 06/16/2025

This study investigates the effects of oxygenated fuels, specifically long-chain alcohols, impact fuel atomization and combustion behavior in CI engines. The objective is to examine how higher n-butanol blending ratios in diesel fuel influence spray dynamics and combustion performance under varying engine conditions using an advanced combustion strategy. Experiments were conducted using a constant volume chamber (CVC) and a rapid compression-expansion machine (RCEM), both designed to replicate CI engine conditions. N-butanol was blended with diesel at ratios ranging from 70% to 90% with 10% increments, and key parameters such as spray formation, cone angle, penetration length, in-cylinder pressure, combustion performance, and efficiency were analyzed. The study also evaluated the effects of varying injection pressures on spray behavior. The results demonstrate that increasing n-butanol content significantly alters spray and combustion characteristics. Higher n-butanol proportions lead

Warsita, I Wayan, Lim, Ocktaeck

CFD Study of Lubrication Pump Starvation Due to Oil Pan Sloshing

2025-01-0213

To be published on 06/16/2025

Dynamic vehicle operation, such as acceleration, deceleration, and tilting, can cause severe oil sloshing in the engine oil pan. This can lead to oil starvation at the pickup tube, compromising lubrication pump performance, and potentially damaging engine components. This study presents a Computational Fluid Dynamics (CFD) multiphase model of an engine oil pan and a system of lubrication pumps, simulated using Simerics-MP+®. A series of numerical simulations are conducted at a given pump speed and extreme oil pan tilt angles or accelerations relevant to a high performance vehicle. Time-dependent oil distributions are visualized, and real-time oil flow rates are monitored at the pickup tubes to assess the impact of oil dynamics and pan position on pick-up tube starvation. This CFD model provides valuable insights into oil pan and pump behavior under extreme vehicle operation conditions, aiding in the design and optimization of lubrication systems to mitigate the risk of oil starvation

Nan, Zhang, Shiyi, Pan, Jing, Liu, Mingliang, Liu, Wei, Wang

Influence of Fuel Surface Tension and Viscosity on Internal Flow Bubble Formation and Atomization in Flash Boiling Sprays

2025-01-0221

To be published on 06/16/2025

Flash boiling atomization is considered a promising atomization technique for combustion applications in automotive powertrains. It can potentially address the deteriorated atomization issue for alternative fuels (such as methanol) in internal combustion engines. However, it has been observed that flash boiling spray atomization for methanol fuels is not as effective as that for traditional alkane-based fuels. This work aims to explain such phenomena using transparent nozzles to reveal the impact of internal vaporization on external spray breakups. Three different working fluids, including methanol, ethanol, and pentane, are tested with elevated temperatures. The flow patterns and external liquid breakup are shown with the high-speed imaging technique. It is found that the internal phase change of the base working fluid is suppressed when ethanol or methanol is used instead of pentane. Consequently, the external liquid breakup is also hindered due to insufficient vapor phase inside the

Zhang, Yijia, Li, Yilong, Wang, Shangning, Zeng, Tingxi, Xu, Min, Hung, David, Li, Xuesong

Development of Simple Models for Performance Estimation of a Spark Ignition Engine Fueled with Ammonia and Hydrogen

2025-01-0238

To be published on 06/16/2025

In engine development, it is needed to investigate engine performance under a lot of conditions. This is called the adaptability test, and it takes a lot of times, money, and manpower. Therefore, decreasing the test is aspired and constructing models that estimate the engine performance is effective for early adoption of ammonia engines. In this research, factors determining the thermal efficiency of a spark ignition engine fueled with ammonia/hydrogen mixtures were investigated and two simple models to estimate the performance were constructed. A diesel based four-stroke single-cylinder spark ignition engine with a displacement volume of 412 cm3 was used. Different compression ratios ε and two pistons with different squish areas were used. Experiments were conducted for total equivalence ratio of 1.0, while changing the LHV (lower heating value) ratio of ammonia and hydrogen. It is shown that higher compression ratio and larger squish velocity expanded the stable operation range of

Ichikawa, Aya, Ogura, Yuto, Yanaoka, Kazuki, Gonzalez Palencia, Juan, Kambara, Shinji, Araki, Mikiya

Development of After-Treatment Systems and Control Strategy for a Hybrid-Dedicated Homogeneous Lean Burn Engine

2025-01-0217

To be published on 06/16/2025

The development of lean-burn gasoline engines has continued due to their significant improvements in thermal efficiency. However, challenges associated with NOx emissions have hindered their mainstream adoption. As a result, the development of an effective NOx after-treatment system has become a key focus in lean-burn engine research. Additionally, HC emissions pose another challenge, as they tend to increase under lean combustion conditions while their conversion efficiency simultaneously declines. This study presents a novel after-treatment system incorporating a lean NOx trap(LNT) and a passive SCR(pSCR) system. This configuration enables efficient NOx reduction at a competitive cost while maintaining operational simplicity. Moreover, conventional catalyst technologies, including three-way catalysts (TWCs) and fuel-cut NOx traps (FCNTs), were optimized to maximize conversion performance under lean operating conditions. To further enhance system performance, various control

Oh, Heechang, Lee, Jonghyeok, Sim, Kiseon, Lim, SeungSoo, Park, Jongil, Park, Minkyu, Kang, Hyunjin, Han, Donghee, Lee, Kwiyeon, Song, Jinwoo

Understanding How Blending Different Ratios of Renewable Fuels with Diesel Impacts the Toxicity of Exhaust Particulates to Human Health

2025-01-0207

To be published on 06/16/2025

The urgent need to decarbonise transport has increased the utilisation of renewable fuels blended with current hydrocarbons. Heavy duty vehicle electrification solutions are yet to be realised and therefore the reliance on diesel engines may still be present for decades to come. Currently, the diesel supplied to fuel stations across the UK is a 7% blended biodiesel, whilst in South Korea a 5% blend is utilised. Biodiesel is produced from renewable sources, for example, crops, waste residue, oils and biomass. Particulates from diesel combustion are known to be toxic due to the presence of polycyclic aromatic hydrocarbons (PAHs), however there is very limited understanding of blending oxygenated fuels on the toxicity of the particulates produced. PAHs are aromatic structures that can be metabolised into chemicals which can disrupt DNA replication and potentially influence cancer mechanisms if inhaled in high quantities. Soyabean methyl-ester (SME) was blended at lower ratios, e.g., 5

Hailwood, Emma, Hellier, Paul, Ladommatos, Nicos, Leonard, Martin

Comparison of HRD and Petro Diesel in Industrial Engine Applications

2025-01-0243To be published on 06/16/2025

Renewable fuels are seen as a key enabler on the path to a lower carbon future. A low greenhouse gas fuel of particular interest is hydrotreated renewable diesel (HRD), also known as hydrotreated vegetable oil (HVO). HRD is of interest because it is a drop-in replacement to existing petroleum fuels used in diesel engines. An experimental investigation was undertaken to evaluate combustion characteristics of HRD versus a standard petroleum diesel. The work was carried out using a 2.5-liter fully instrumented single-cylinder research engine. This engine was chosen because it provides a very precise view of the difference in combustion and emissions of the fuels. Results represent the difference in combustion characteristics of the fuels, rather than potential differences in engine performance seen in a production engine, as each particular engine model will react a bit differently to the changes in combustion. The engine was operated according to three ISO 8178-4 test cycles: C1, D2, and

Bardell, Michael, Abi-Akar, Hind, Seiler, Patrick, Nash, Brady, McMahon, Donna, Ioannou, Marios

Parametric Analysis of Injector Operational Parameters, Charge Dilution, and Intake Valve Opening on In-Cylinder Motion and Flame Development in an Automotive, Lean-Burn, Gasoline Engine with High-Tumble

2025-01-0198

To be published on 06/16/2025

The effect of injection pressure, start of injection (SOI) timing, charge dilution, and valve timing on charge motion and early flame development was investigated for a pre-production automotive gasoline engine. Experiments were performed in a single-cycle optical engine designed to represent the high-tumble (Tumble ratio = 1.8), lean-burn engine. Time-resolved particle image velocimetry (PIV) was used to characterize velocity flow fields throughout the swept volume during the intake and compression strokes. Diffuse back illuminated imaging allowed for visualization and quantification of the injected liquid fuel spray and its interactions with the tumble vortex. Hydroxyl (OH*) chemiluminescence imaging was performed to image spark channel elongation and early flame kernel development. It was observed that an optimal injection timing of 320° before top dead center (bTDC) resulted in attenuation of the tumble motion and an associated reduction in compression flows that shifted the tumble

MacDonald, James, Ekoto, Isaac, Han, Donghee, Lee, Jonghyeok

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