Browse Topic: Pistons

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Ca Additive and In-Cylinder Condition on Promotion of Abnormal Combustion in Supercharged SI Engine2025-32-000411/03/2025
Recently, global warming is becoming seriously. In the field of internal combustion engine, the thermal efficiency has to improve in the practical use. One of the current trends with spark ignition engine (SI engine) is “downsizing” which is equipped supercharger with the downsized displacement. The downsizing engine is popular in the field of the SI engine. However, one of the problems is the abnormal combustion so called Low Speed Pre-Ignition (LSPI) [1]. The LSPI occurs the engine operation which is low speed and high load condition. It has to be avoided, because the SI engine is broken and the improvement of thermal efficiency is obstructed. A lot of researchers have been reported about the mechanism of LSPI [2, 3]. One of the sources of LSPI would be the lubricating oil droplets in cylinder. One of the methods to avoid LSPI, it has been adjusted the ingredients of oil additive in lubricating oil. The state of the art of lubricating oil standard has been established anti-LSPI
kitano, Kaito, Tanaka, Junya
Study of Combustion Characteristics of a Two-Stroke Opposed Piston Engine using Low-Octane Fuels2025-32-002811/03/2025
Various fuels are being considered as the next generation of carbon neutral fuels, including methanol, ethanol, and SAF. These have widely different ignition properties. Methanol and ethanol are high-octane fuels, so there are no major problems with their use in gasoline engines. However, SAF is a hydrocarbon with a large molecular weight, so it has a fundamentally low octane rating and is not easy to use in SI engines. In order to put carbon-neutral fuels of various properties into practical use, it is effective to develop a technology that allows fuels with low octane to be operated in SI engines. Therefore, in this study, basic research was conducted on the combustion of fuels with low octane using PRF fuel in opposed-piston engines. Opposed piston engines are characterized by their 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
Yamazaki, Yoshiaki, Okawara, Ikumi, Liu, Jinru, Iijima, Akira
Development of CAE Technology for the Design Support of Piston Pin Circlip2025-32-001511/03/2025
This study focuses on the technology for establishing design criteria for the piston pin circlip (hereinafter referred to as "circlip"), which is a component that holds the engine piston pin. During the development of high-revving engines, failure of the piston sometimes becomes a problem, and the main factors are fatigue failure of the piston and falling of the piston pin. The falling of the piston pin is caused by the circlip disengaging from the groove by the inertial force due to the vertical motion of the piston. The circlip is compressed to the size of the piston circlip groove and assembled to the piston. Therefore, in order to prevent the circlip from falling out, it is necessary to compress it more and increase the reaction force acting on the groove. However, this measure raises concerns about the deterioration of the ease of assembly of the circlip. Therefore, it is necessary to establish evaluation criteria that prevent the circlip from disengaging and deterioration of its
Ishizuka, Atsushi, Watanabe, Naoto
Advanced Multi-Fidelity Simulation of Piston Oil Jet Cooling in High-Performance Engines2025-32-008111/03/2025
The development of next-generation hydrogen-fueled engines introduces critical challenges related to thermal loads within the combustion chamber, particularly in high-performance applications. To address the extreme temperatures encountered, effective piston cooling strategies, such as oil jet impingement, are essential. Accurately predicting thermal stresses to prevent component failure is therefore crucial. However, numerical simulations often come with significant computational costs. This paper presents a comprehensive multi-fidelity modeling approach to predict the thermal behavior of pistons under these demanding conditions. The model integrates a simplified 3D thermal representation of the piston, a lumped-parameter mechanical model of the piston-liner assembly, and convective boundary conditions obtained at various levels of fidelity, from high-level Computational Fluid Dynamics (CFD) simulations to literature correlations. Additionally, the study examines the influence of
Sassoli, Andrea, Romani, Luca, Ferrara, Giovanni, Paolicelli, Giovanni, Balduzzi, Francesco
An Investigation into the Impact of Cylinder Count on the Efficiency of Opposed Piston Two-Stroke Compression Ignition Engines03-18-06-003710/09/2025
The gas exchange process of opposed piston two-stroke (OP2S) diesel engines is primarily driven by the pressure differential between the intake and exhaust, making them susceptible to cylinder-to-cylinder crosstalk, and therefore to cylinder count. This study examined how cylinder count influences brake efficiency in OP2S engines. Using an experimentally validated 1D engine model, three architectures, ranging from two to four cylinders, were created and simulated across their full operating ranges. To isolate the impact of cylinder count, all configurations employed identical cylinder and port geometries, and identical but scaled electrically assisted turbocharger based airpaths. The engines were also controlled to consistent trapped conditions at a given operating condition, resulting in comparable closed-cycle efficiencies. Comparisons were then made using both scaled electrified airpaths and by assuming isentropic airpath work, to assess the impact of airpath efficiency on the
Vorwerk, Erik Scott, Prucka, Robert, Lawler, Benjamin, Huo, Ming
Effect of Flow Speed and Turbulence on Methane Combustion in a Rapid Compression Machine2025-01-039310/07/2025
Recent experimental work from the authors’ laboratory demonstrated that applying a boosted current ignition strategy under intensified flow conditions can significantly reduce combustion duration in a rapid compression machine (RCM). However, that study relied on spark anemometry, which provided only localized flow speed estimates and lacked full spatial resolution of velocity and turbulence near the spark gap. Additionally, the influence of turbulence on combustion behavior and performance across varying flow speeds and excess air ratios using a conventional transistor-controlled ignition (TCI) system was not thoroughly analyzed. In this study, non-reactive CFD simulations were used to estimate local flow and turbulent velocities near the spark gap for piston speeds ranging from 1.2 to 9.7 m/s. Simulated local velocities ranged from 0.7 to 96 m/s and were used to interpret experimentally observed combustion behavior under three excess air ratios (λ = 1.0, 1.4, and 1.6). Combustion was
Haider, Muhammad.Shaheer, Jin, Long, Yu, Xiao, Reader, Graham, Zheng, Ming
Study on Oil Film Thickness of Piston Skirt Pattern Coating in a Commercial Vehicle Diesel Engine2025-01-039710/07/2025
In recent years, there has been a trend towards lower engine speeds and downsizing of diesel engines to improve fuel efficiency. This has the advantage of reducing frictional losses in the hydrodynamic lubrication condition but causes severe lubrication in the mixed lubrication condition. In order to reduce friction losses without the risk of abnormal wear or seizure, pattern coatings of the piston skirt area have been proposed. In this study, the oil film thickness between piston and cylinder was measured to investigate the effect of pattern coating on the oil film thickness. The oil film thickness between the piston and cylinder were measured by the laser-induced fluorescence method using the optical fibers embedded in the cylinder. The oil film thickness on the piston skirt was successfully measured under the engine operating conditions for the medium duty Direct Injection (DI) diesel engine. The oil film thickness for the pattern coatings was compared with that for the solid
Tanimoto, Keisuke, Ito, Akemi, Sumoto, Masayuki
Approaches for Mechanical Development and Validation of Hydrogen Internal Combustion Engines2025-01-039810/07/2025
Hydrogen Internal Combustion Engines (H2 ICEs) are seen as a viable zero-emission technology that can be implemented relatively quickly and cost-effectively by automotive manufacturers. The changed boundary conditions of a hydrogen-fueled engine in terms of mechanical and thermal aspects require a review and potential refinement of the design especially for the 'piston bore interface' (liner honing, ring and piston design) but also for other engine sub-systems, e.g. the crankcase ventilation system. The influence of oil entry into the combustion chamber is even more important in hydrogen engines due to the risk of oil-induced pre-ignition. Therefore, investigations of the interaction between friction, blowby and oil transfer into the combustion chamber were performed and are presented in this paper. During the investigations, experimental tests were carried out on a single-cylinder engine ('floating liner') and on a multi-cylinder engine. The 'floating liner' concept allows the crank
Plettenberg, Mirko, Gell, Johannes, Grabner, Peter, Gschiel, Kevin, Hick, Hannes
A Study of Variables Affecting Piston Skirt Loads on the Oppossed Piston Two Stroke Diesel Engine2025-01-049909/16/2025
A kinematic model of primary piston motion was developed along with a simplified combustion model for the purpose of evaluating various factors that could impact the piston skirt thrust loads of an Opposed Piston Two Stroke Diesel engine. The assessment considered connecting rod length, wrist pin mass, peak cylinder pressure, indicated torque, and wrist pin offset. The results show that small changes in connecting rod length could realize significant improvements in piston skirt friction as well as increased engine performance. The results indicate that small increases in overall engine width should be considered when optimizing for reduced oil consumption and enhanced piston skirt lubrication.
Srodawa, John
Enhancing Robustness of Electro-Hydraulic Brake-by-Wire Actuators via Linear Active Disturbance Rejection Control2025-01-034109/15/2025
In recent years, motorsport has increasingly focused on environmental concerns, leading to the rise of hybrid and fully electric competitions. In this scenario, electric motors and batteries take a crucial role in reducing the environmental impact by recovering energy during braking. However, due to inherent limitations, motors and battery cannot fully capture all braking power, necessitating the use of standard friction brakes. To achieve an efficient balance between electric motors and friction brakes, the brake pressure can no longer be directly controlled by the driver. Instead, it must be computed by the Vehicle Control Unit (VCU) and sent to a smart actuator, i.e. the Brake-By-Wire (BBW), which ensures that the required pressure is applied. The standard approach to achieve precise pressure control is to design a nested Proportional-Integral-Derivative (PID) control architecture, which requires an accurate nominal model of the system dynamics to meet the desired tracking
Gimondi, Alex, Dubbini, Alberto, Riva, Giorgio, Cantoni, Carlo
The Challenges of Measuring Residual Brake Drag using Different Test Apparatuses and Methods to Mitigate Inaccuracies2025-01-034309/15/2025
As automotive manufacturers have tried to set themselves apart by reducing emissions, and increasing vehicle range/fuel economy by eliminating any energy loss from inefficiencies on the vehicle, the brake corners have been an area of interest to reduce off-brake torque to zero in all conditions. Caliper designers can revise some attributes like piston seal grooves, and pad retraction features to reduce drag, but even if a caliper is designed perfectly in all aspects, trying to measure it in a reliable and repeatable manner proves to be difficult. There are many ways to measure brake drag all with ranging complexity. Some of the simplest measurements are the most repeatable, but it excludes the majority of the vehicle inputs. The most vehicle representative testing requires the most complex equipment and comes with the most challenges. This paper will focus mainly on the different ways residual brake drag can be measured, the benefits and challenges to each of them, the problems trying
Retting, Joshua
Thermal Stress Reduction in Diesel Engine Pistons Using Semitransparent Ceramic Coatings: A 3D Numerical Study with OpenFOAM2025-24-000309/07/2025
This research focuses on the thermal analysis of internal combustion engine pistons, evaluating the effects of high-temperature exposure during operation. A three-dimensional numerical study is conducted using OpenFOAM, modifying the software’s governing equations to analyze temperature distribution in different piston geometries. The study aims to assess the spatial temperature variation within the entire volume of the piston, providing a detailed understanding of heat transfer mechanisms. A multilayer approach is implemented, considering various configurations of ceramic coatings with distinct thermal and optical properties. The investigation incorporates an internal heat source model, where the heat absorption characteristics of the coating material influence the thermal behavior of the system. By evaluating aluminum- and titanium-based ceramic coatings, the study examines how semitransparency and heat radiation absorbance affect heat accumulation and transfer. The results highlight
Gutierrez, Marcos, Taco, Diana, Bösenhofer, Markus
Effects of Piston Pre-Heating and Friction Reduction on Cold-Start Charge Preparation for DI Methanol Engine: An In-Cylinder CFD Study2025-24-004009/07/2025
Methanol is gaining interest as a renewable fuel for Internal Combustion Engine (ICE) applications. A key challenge for this fuel is its low evaporation rate at low temperatures, which makes cold-starts problematic, particularly in cold climate conditions. The first combustion cycles are characterized by a low combustion chamber temperature and high engine friction. In previous work by the authors, a practical approach was presented to pre-heat the pistons and pre-condition the bearings, thereby reducing friction. In this article, in-cylinder Computational Fluid Dynamics (CFD) modeling is used to study the charge preparation of a DI-SI methanol ICE up to the end of compression. The model is calibrated in-house using measurements from a warm methanol engine. The piston temperature is varied within the range expected from the pre-heating and pre-lubricating device. Friction reduction is translated into the reduced amount of fuel needed to generate the IMEP required to idle the engine
Bovo, Mirko, Mubarak Ali, Mohammed Jaasim
Schaeffler optimizes rolling bearings for hydraulic and axle drives25TOFHP08_0608/01/2025
Rolling bearings with optimized friction and performance characteristics can have a significant influence on reducing the power loss, design envelope and weight of hydraulic motors and pumps, gearboxes and axles in construction machinery. If correctly designed, rolling bearings can make a significant contribution to reducing carbon dioxide emissions. Most construction machinery is still operated conventionally, using diesel engines and hydraulic components. In the widely used adjustable axial piston pumps and motors, the input and output shaft are usually supported by two tapered roller bearings that are adjusted against each other. When designing the bearing support, it is advisable to reduce the preload to precisely the required minimum allowed by the load spectrum. The lower bearing preload leads to permanently lower axial forces between the tapered roller end face and inner ring rib and, therefore, to a corresponding reduction in frictional torque.
Scharting, Stefan
Method for Externally Controlled Availability of Lubricating Oil in Internal Combustion Engines2025-01-030207/02/2025
Reduced raw emissions from internal combustion engines (ICE) are a key requirement to reach future green-house-gas and pollutive emissions regulations. In parallel, to satisfy the need for increased engine efficiencies, the friction losses of ICEs gains attention. Measures to reduce parasitic drag inside the piston assembly such as reduced piston-ring pretension or thinner grade engine oils may increase oil ingress into the combustion chamber. The oil ingress is known to imply increased particle emissions directly counteracting the raw emission reduction target of engine development. To resolve this target conflict, the transport mechanisms of oil into the combustion chamber are the topic of current research. Specially developed research engines featuring a vertical optical window come with big potential to visualize the phenomena of the oil behavior inside the piston assembly group. Such ‘glass-liner’ engines play a pivotal role in identification and quantification of local and global
Stark, Michael, Fellner, Felix, Härtl, Martin, Jaensch, Malte
Flame Developments of Pilot Diesel Ignited Hydrogen Jet in an Optical Dual Direct Injection Engine2025-01-023706/16/2025
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
Effects of Injection and Intake Timing on Atomization and Combustion in a Hybrid Gasoline Direct Injection Optical Engine under the Low-Speed Low-Load Condition2025-01-020306/16/2025
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
Analysis of Combustion Characteristics of a Small 2-Stroke Opposed Piston Engine Using an Optically Accessible Engine and Numerical Analysis2025-01-022306/16/2025
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
Development of a High-Frequency Measurement Apparatus for Evaluating Piston Friction in a Small Gasoline Engines2024-32-010004/18/2025
Efforts to enhance fuel efficiency in small gasoline engines, vital for reducing CO2 emissions, are concentrated on minimizing piston friction losses. Achieving this balance while addressing concerns such as piston seizure prevention and minimizing oil consumption presents challenges, particularly in small gasoline engines operating at higher speeds where the risk of piston seizure is significant. Hence, there is a critical need for accurate methods to measure piston friction. This study introduces the development of a measurement apparatus employing the floating liner method, initially devised by Takiguchi [1] and further adapted by Yamasaka for a mono-cylinder air-cooled gasoline engine [2, 3]. Yamasaka’s research successfully investigated the correlation between the apparatus’s natural frequency and the maximum engine speed measurable, achieving piston friction measurement up to 5000 rpm. Expanding on this achievement, this research aims to broaden the application of the floating
Honda, Riku, Ito, Akemi, Saika, Santa, Yamase, Ryouta, Hasegawa, Tatsuhiko, Sakioka, Takeru, Suda, Naoyuki, Ninomiya, Yoshinari
Prediction of Pre-Ignition Borderline on Supercharged SI Engine by Livengood-Wu Integral2024-32-000804/18/2025
The LSPI (Low Speed Pre-Ignition) is one of the consecutive abnormal combustion cycles of supercharged SI engine with direct injection fuel supply system [1]. The LSPI occurs when the engine is running at low speed and high load condition. It is important for the SI engine to control essentially with alternative fuel, e-fuel and hydrogen in the future. It is considered that the LSPI would be caused by the autoignition of the deposit, the lubricating oil from ring crevice, the lubricating oil from piston crown and so on [2, 3, 4, 5]. Among of these causes, this research focuses on the scattering lubricating oil from piston crown. The previous our research has reported on the two points. One is about the frequency and quantity of the lubricating oil scattering from piston crown [6]. Another is about the frequency of abnormal combustion by the engine test [7]. As the result, it has been cleared that the frequency of abnormal combustion is 1/10 of scattering frequency of the lubricating
Omori, Takaya, Tanaka, Junya
CFD Analysis of Pintle-Nozzle Spray for Swirl Chamber Type Small Diesel Engine -Application of Hole-Nozzle Atomization Model to Pintle-Nozzle2024-32-010904/18/2025
Swirl chamber combustion system is commonly used for IDI (In-Direct Injection) diesel engine. It is characterized by swirl combustion chamber arranged in cylinder head, main combustion chamber with shallow piston recess and connecting throat where fuel spray and flame mixture is ejected out from the swirl chamber to the main chamber [1]. Fuel is supplied in the swirl chamber and a pintle type nozzle is often used in this type engine as its simple structure and robustness for operating condition. In this paper, numerical simulation of a pintle nozzle spray was focused on and simulated results were compared with high speed photo data obtained in a constant volume vessel (CVV). Spray angle and tip penetration were mainly evaluated, but simulated angle and penetration could not be matched simultaneously to these characteristics of the pintle nozzle spray when conventional spray models were used for the simulation. To overcome this mismatch, “Multi-hole replacement model” was newly
Okazaki, Tadao, Fujiwara, Tsukasa
Development of Pistons Suitable for Compact Air-Cooled Engines2024-32-003004/18/2025
For the realization of carbon neutrality, we are working on research to improve the thermal efficiency of engines for motorcycles. Friction losses in the cylinder bore account for about 40% of the total friction losses of the engine (Figure 1), which is directly related to thermal efficiency improvement [1]. Air-cooled engines are suitable for motorcycles due to their simplicity and light weight, but it is difficult to achieve both efficiency and reliability. Friction in the cylinder is generated by piston scuffing. The oil film distribution of the piston-skirt(=skirt) is thin at the center of the skirt and thick at the edge. To reduce piston friction, it is effective to make the thin oil film at the center of the skirt thicker. On the other hand, to reduce oil consumption, the oil film must be thinned. However, air-cooled engines, which are difficult to keep the cylinder temperature constant, cannot make the clearance between the cylinder bore and the piston small. An increase in
Suda, Naoyuki, Hihara, Taiki, Ninomiya, Yoshinari
Experimental Investigation for the Effect of Cavity Geometry on the Flame Propagation and Auto-Ignition in RCM2024-32-006004/18/2025
In this experiment, we investigated the auto-ignition and flame propagation behavior by using flat piston and cavity pistons which has different geometries, depth, and width of the cavity. In this study, flame behavior inside the cavity is visualized with the ion-probes, which is embedded every 3mm radially from the center of the piston. We also used the pressure sensor in the combustion chamber and high-speed camera through the quartz window near the cylinder wall. Flame appearance obtained with high-speed camera shows that the flame propagation of the cavity piston is faster than that of flat piston. This is considered because of the outward induced flow in the squish area. That is, the flame propagation inside the wide cavity area pushes the unburned gas outwardly and induced the outward flow in the squish area. This induced flow promotes the flame propagation. As a result, unburned gas is consumed rapidly, and thus, it is also found that the intensity of Knocking is reduced by
Yamaguchi, Riki, Esaki, Daigo, Tateishi, Tokua, Osaf, Ali Hassan, Miyoshi, Akira, Shimokuri, Daisuke, Yatsufusa, Tomoaki, Terashima, Hiroshi, Hara, Takaya, Honda, Yuya, Tadokoro, Tadashi, Kawano, Michiharu
Research on Basic Characteristics of a Two-Stroke Opposed Piston Engine2024-32-011204/18/2025
This study investigated the performance characteristics of a two-stroke opposed piston engine that is capable of constantly operating with high power output and high efficiency. An investigation was also made of the performance obtained by applying a pseudo uniflow condition as a measure against large hydrocarbon (HC) emissions owing to blow-by of unburned mixture, which is an issue of two-stroke engines. The test engine had a displacement of 127 cm3 and a bore and stroke of 48 x 70 mm. One-point and dual-point ignition systems were used, and regular gasoline was supplied as the test fuel using a carburetor-based fueling system. Experiments were conducted at engine speeds of 1500 and 3000 rpm at ignition timings of 45 deg. and 35 deg. before top dead center. The results showed that large quantities of HC emissions were emitted because stable combustion was not achieved. This revealed that a stronger uniflow condition must be applied as a countermeasure rather than a simple pseudo
Fukushima, Shumpei, Uehara, Ryota, Hayashi, Yoshiaki, Igarashi, Ryo, Tokita, Kazuho, Iijima, Akira
Detecting Piston Ring–Cylinder Liner Metal–Metal Contact in a Fired Large Marine Diesel Engine Using Piezoelectric Transducers03-18-03-001704/09/2025
Shear-polarized ultrasonic sensors have been instrumented onto the outer liner surface of an RTX-6 large marine diesel engine. The sensors were aligned with the first piston ring at top dead center and shear ultrasonic reflectometry (comparing the variation in the reflected ultrasonic waves) was used to infer metal–metal contact between the piston ring and cylinder liner. This is possible as shear waves are not supported by fluids and will only transmit across solid-to-solid interfaces. Therefore, a sharp change in the reflected wave is an indicator of oil film breakdown. Two lubricant injection systems have been evaluated—pulse jet and needle lift-type injectors. The needle lift type is a prototype injector design with a reduced rate of lubricant atomization relative to pulse jet injectors. This is manifested as a smaller reduction in the reflected ultrasonic wave, showing less metal–metal contact had occurred. During steady-state testing, the oil feed rate was varied; the high flow
Rooke, Jack, Li, Xiangwei, Dwyer-Joyce, Robert S.
High-Speed Optical Diagnostics of Misfire Limits in a Spark-Ignited Heavy-Duty Hydrogen Engine2025-01-840104/01/2025
This study investigates the ignitability of hydrogen in an optical heavy-duty SI engine. While the ignition energy of hydrogen is exceptionally low, the high load and lean mixtures used in heavy-duty hydrogen engines lead to a high gas density, resulting in a much higher breakdown voltage than in light-duty SI engines. Spark plug wear is a concern, so there is a need to minimise the spark energy while maintaining combustion stability, even at challenging conditions for ignition. This work consists of a two-stage experimental study performed in an optical engine. In the first part, we mapped the combustion stability and frequency of misfires with two different ignition systems: a DC inductive discharge ignition system, and a closed-loop controlled capacitive AC system. The equivalence ratio and dwell time were varied for the inductive system while the capacitive system instead varied spark duration and spark current in addition to equivalence ratio. A key finding was that spark energy
Hallstadius, Peter, Saha, Anupam, Sridhara, Aravind, Andersson, Öivind
Comparative Evaluation of Untextured and Textured Surfaces for Wear, Wettability and Friction Characteristics2025-01-833104/01/2025
Reduction of frictional losses by changing the surface roughness in the form of surface textures has been reported as an effective method in reducing friction in the boundary regime of lubrication. Laser-based micro texturing has been mostly used to create these texture patterns and it is reported that it can reduce the frictional resistance by ~20-50%. However, the use of laser-based techniques for texture preparation led to residual thermal stress and micro cracks on the surfaces. Hence, the current study emphasizes using conventional micromachining on piston material (Al alloy Al4032) to overcome this limitation. Three variations of semi-hemispherical geometries were prepared on the surface of Al alloy with dimple depths of 15, 20 and 40 μm and dimple diameters of 90, 120 and 240 μm. Prepared textured surfaces with untextured surfaces are compared in terms of wear, wettability, and friction characteristics based on Stribeck curve behaviors. Results of this investigation demonstrated
Sahu, Vikas Kumar, Shukla, Pravesh Chandra, Gangopadhyay, Soumya
Impacts of Injection Pressure on Split-Injection Energy-Assisted Compression-Ignition Combustion of Low Cetane Number SAFs with a Gaussian-Shaped Ribbed Piston Bowl Design2025-01-835004/01/2025
The impact of injection pressure on a split-injection energy-assisted compression-ignition (EACI) combustion strategy was studied in an optically accessible engine with a custom ribbed piston bowl design. Three injection pressures (600, 800, and 1000 bar) were investigated for three split-injection dwells (1.5, 2.0, and 2.5 ms) with a fixed second injection timing of -5.0 CAD. The Gaussian-shaped ribbed piston bowl design was employed to position hot combustion gases from the first injection near the centrally located injector to enable rapid ignition and mixing-controlled combustion of the second injection. At 600-bar injection pressure, as injection dwell was shortened, relocation of hot combustion gases near the injector became increasingly more difficult due to less available time for relocation and due to the higher in-cylinder densities at the start-of-injection (SOI) for the first injection. Increased injection pressure (800 and 1000 bar) improved the relocation of the first
Amezcua, Eri, Stafford, Jacob, Kim, Kenneth, Kweon, Chol-Bum, Rothamer, David
Three-Body Abrasive Wear Surface Characterization of Military Diesel Engine Piston Rings and Cylinder Bores2025-01-834604/01/2025
Two 50-hr engine dynamometer tests were conducted on 12-cylinder diesel military engines with differing piston ring sets. Engine A exhibited more than double the oil consumption over engine B. An investigation was conducted to explain why the oil consumption differed by employing several posttest analytical techniques including cylinder bore geometry measurements, surface metrology, wear characterization, and chemical analysis on the piston rings and cylinder wall coatings. The 3D colormaps of cylinder bore deformation showed uneven volumetric deformation through the piston stroke instead of 2D plane deformation. It was found that the primary reason of high oil consumption was direct loss of sealing between the piston, piston ring and cylinder bore due to predominately abrasive wear, three-body abrasive wear and bore polishing. Furthermore, the compromised sealing of the combustion chamber led to blow-by. Carbon deposits, corrosive byproducts, surface abrasives, loss of desired surface
Thrush, Steven, Chen, Aijie, Foley, Michael, Sebeck, Katherine, Boufakhreddine, Ziad
3D Design and Analyses of an IC Engine Piston under Fatigue Test Conditions Using CNTs for the Next-Generation of Motorcycles2025-01-835904/01/2025
CNTs play an important role in modern engineering projects, especially in engine pistons design for the next-generation of motorcycles. This work presents a comprehensive analyses proposed project using finite element method under actual operating conditions purpose performance evaluation of a motorcycle engine piston design, investigating the suitability of four distinct materials. Precise material properties adhering to linear elastic isotropic behavior were defined within the software environment and proposed advanced nanomaterial ensuring accurate representations of the proposed under the prescribed loading scenarios. The primary objective was to identify the optimal material choice for the piston, ensuring superior strength, minimal deformation, and lightweight characteristics essential for high-performance engine applications. Moreover interpreting and understanding the dynamic behavior of common and advanced engineering materials. Through a comprehensive evaluation of the
Ali, Salah H. R., Ahmed, Youssef G. A., Ali, Amr S.H.R.
Experimental Analysis of Piston Surface Temperature in a Heavy-Duty Compression Ignition Engine2025-01-838304/01/2025
The heat transfer processes occurring in a compression ignition engine are complex, especially considering flame-wall interaction on the piston crown from impinging jets. To study the heat flux occurring on the piston in a heavy-duty diesel engine, a piston was instrumented with fifteen thermocouples and a wireless telemetry system. Eight of the thermocouples are high speed surface thermocouples placed primarily in regions with significant flame-wall interaction, providing crank-resolved surface temperature data. This work presents the first experimental datasets collected with this instrumented piston, describing in detail the thermocouple location selection process as well as data processing and uncertainty quantification for the high-speed surface thermocouples with a particular emphasis on cyclic variability and sensor-to-sensor variability. With this methodology established, data from this piston can be used for modeling and simulation studies as well as for studying the impact of
Gainey, Brian, Datar, Aditya, Ravikumar, Avinash, Bhatt, Ankur, Vedpathak, Kunal, Kumar, Mohit, Gingrich, Eric, Tess, Michael, Korivi, Vamshi, Lawler, Benjamin
A Proposed RE-Method for Redesigning Damaged CAM Gears in Automotive Engines Using Image Processing and 3D CAD Model2025-01-863404/01/2025
Cam gear is a critical component of the timing system in an internal combustion engine, ensuring the synchronized opening of the engine valves, pistons, and rotating parts, but their unavailability may result in long-term downtime or expensive replacement. Reverse engineering (RE) systems also play an important role in promoting sustainable practices projects in automotive technologies. The study focuses on presenting a proposed method for redesigning damaged parts in engines using image processing technology by creating an-accurate CAD model. In addition to clarifying of the expected causes that led to cam gear damage. The proposed method involves taking a high-resolution image of the damaged part, then applying advanced image processing algorithms to analyze and reconstruct the geometry of the part. The data is then converted into a high-resolution 3D CAD model. This approach aims to address the challenges of replicating worn or broken parts, providing a cost-effective maintenance
Ali, Salah H. R., Ehab, Eslam, Barakat, Ebrahim, Younes, Abdelrahman, Ali, Amr S.H.R.
Experimental Study of Direct-Injection Compression-Ignition Hydrogen Combustion in an Opposed-Piston Two-Stroke (OP2S) Engine2025-01-843004/01/2025
The future heavy duty powertrain market is expected to be more diverse, with a gradual shift towards cleaner and more sustainable alternative fuels. Among various options, the hydrogen Internal Combustion Engine (ICE) holds the promise of significantly reducing carbon emissions while leveraging existing ICE technology. However, it also faces substantial challenges related to engine performance, fuel storage and delivery, infrastructure development, economic feasibility, safety and market acceptance. This paper focuses on performance challenges of hydrogen engine, including knock and pre-ignition, as well as low thermal efficiencies, and introduces the Opposed-Piston Two-Stroke Hydrogen ICE (OP2S-H2ICE) as a potential solution. The study demonstrates that OP2S-H2ICE can operate using direct injection, compression-ignition (CI) combustion solely with hydrogen, under various low-load to partial load conditions. Specifically, as the load increases, the combustion transitions from partial
Huo, Ming, El-Hannouny, Essam, Longman, Douglas
Flame Extinguishing and Heat Transfer in the Combustion Chamber of a Hydrogen Engine2025-01-842004/01/2025
Conversion to hydrogen of automobile internal combustion engines powered by fuels of petroleum origin is the most important direction for solving environmental, energy and climate problems of modern civilization. A number of researchers, based on experimental studies, note the presence of a phenomenon of a significant increase in heat losses in hydrogen engines compared to gasoline engines. This phenomenon is explained by an increase in temperature and speed of movement of the working fluid. In this paper, it is shown that the main reason for the increase in thermal losses is the ability of the hydrogen flame to penetrate into the narrow gap between the piston and the engine sleeve. This problem has not been discussed in engine theory before. D mathematical modeling of flame penetration and extinguishing processes in the specified gap of a hydrogen engine (D/S=86/86 mm/mm, Ne=60 kW, n=5500 min-1) was carried out. Critical gap sizes for various fuels have been established, heat transfer
Kavtaradze, Revaz, Natriashvili, Tamaz, Gladyshev, Sergey
Designing Next-Generation Piston Geometry for LPG Powered Spark Ignition Engines: An Integrated CFD and Experimental Approach2025-28-012302/07/2025
The efficiency of combustion has a major impact on the performance and emission characteristics of a spark-ignited LPG (Liquified Petroleum Gas) engine. The shape of the combustion chamber determines the homogeneous charge intake velocity, which is crucial for the turbulent motion that encourages flame propagation and quickens combustion. It need the right amount of compression ratio, charge squish velocity and turbulent kinetic energy to sustain combustion and propel laminar flames. There are a number of names for the motion of the charge within the cylinder: swirl, squish, tumble and turbulence. All of these terms affect how air and fuel are mixed and burned. Piston shape affects in-cylinder motion, which in turn reduces fuel consumption and improves combustion characteristics. The shape of the piston quench zone has a substantial impact on the charge velocity inside the combustion chamber. The impact on charge motion was analyzed using computer modeling using STAR-CD on pentroof
Sagaya Raj, Gnana, R L, Krupakaran, Pasupuleti, Thejasree, Natarajan, Manikandan
Analysis of Injection Characteristics and Structural Reliability of Marine Methanol Fuel Injectors2025-01-711601/31/2025
Nowadays, the energy transition is at the most critical moment. In order to achieve the emission reduction target of ships, a form of boosting piston inside methanol fuel injector has been carried out. The physical property fluctuations and phase change of methanol under high pressure have been considered in the design phase. 1D-3D coupling method is used to comprehensively evaluate the performace of the injector. To this end, an Amesim simulation model is established to systematically study and analyze the injection characteristics. The injection performance of the injector under four typical loads are calculated, which is evaluated from the perspectives of injection quantity, injection duration, valve response, and leakage of boost components. In the nozzle block, the cavitation intensity of methanol is stronger than that of diesel. To reduce the possibility of cavitation erosion, as a consequence, a CFD model is established to optimize the structure of nozzle components. By adding
Yang, Li, Wen, Liming, Zhang, Hanwen, Lu, Gangao, Dong, Weijie
Digital Twin-Enabled Fault Detection for Suspension Systems in Autonomous Mining Haulage Vehicles2024-36-017012/20/2024
Autonomous vehicles for mining operations offer increased productivity, reduced total cost of ownership, decreased maintenance costs, improved reliability, and reduced operator exposure to harsh mining environments. A large flow of data exists between the remote operation and the ore haul vehicle, and part of the data becomes information for the maintenance sector which it monitors the operating conditions of various systems. One of the systems deserving attention is the suspension system, responsible for keeping the vehicle running and within a certain vibration condition to keep the asset operational and productive. Thus, this work aims to develop a digital twin-assisted system to evaluate the harmonic response of the vehicle’s body. Two representations were created based on equations of motion that modeled the oscillatory behavior of a mass-damper system. One of the representations indicates a quarter of the ore transport truck’s hydraulic system in a healthy state, called a virtual
Rosa, Leonardo Olimpio, Branco, César Tadeu Nasser Medeiros
Enhancing Diesel Engine Performance with Silica Coated Pistons and Cassia Fistula Biodiesel Blends: A Pathway to Cleaner and Efficient Energy2024-01-522212/10/2024
This study investigates the influence of Silica-Diamond-Like Carbon (Si-DLC) coated pistons on performance metrics of diesel engine fuelled with various blends of Cassia Fistula biodiesel (CFBD10, CFBD20, CFBD30, and CFBD40). The primary focus is on key performance metrics, including Brake Thermal Efficiency (BTE), Brake Specific Energy Consumption (BSEC), and Exhaust Gas Temperature (EGT). The results demonstrated improvement in BTE and EGT, alongside a reduction in BSEC across all biodiesel blends compared to conventional diesel. Specifically, at full engine load, CFBD10 exhibited a BTE of 33.41%, which is 3.17% higher than neat diesel in the stock engine. At part load and no-load scenarios, improvements of 2% and 0.51% over neat diesel were recorded. During no-load conditions, the BSEC for CFBD10 was measured at 9.901 MJ.kW-hr, 0.738 MJ.kW-hr lower than that of neat diesel. Further increases in Cassia fistula blends resulted in higher BSEC values due to lower calorific content
Veeraraghavan, Sakthimurugan, De Poures, Melvin Victor, Madhu, S., Palani, Kumaran
Effect of Temperature on Aluminum Alloy (Al4032) Using Textured Surface2024-28-016012/05/2024
The larger domain of surface texture geometry and other input variables related to engine operation, i.e., elevated temperature, has remained to be studied for finding suitable surface texture for real-time engine operations. In previous efforts to find suitable surface texture geometry and technique, the tribological performance of the piston material (Al4032) with dimples of varying diameters (90 to 240 μm) was evaluated under mixed and starved lubrication conditions in a pin-on-disk configuration. The disc was textured using a ball nose end mill cutter via conventional micromachining techniques. The area density and aspect ratio (depth to diameter) of the dimples were kept constant at 10% and 1/6, respectively. SAE 20W-40 oil was used as a lubricant with three separate drop volumes. The experiments were conducted in oscillating motion at temperatures of 50, 100 and 150°C. Conventional micromachining achieved improved dimensional precision and minimized thermal damage. Textured
Sahu, Vikas Kumar, Shukla, Pravesh Chandra, Gangopadhyay, Soumya
Parametric Study of Enhanced Combustion Based on Nozzle Protrusion and Spray Angle of High-Power-Density Diesel Engine2024-01-428011/05/2024
The goal of high-power-density diesel engines is to enhance combustion efficiency and reduce fuel consumption, which has always been the focus of diesel engines in addressing energy and environmental challenges. A high injection pressure allows a significant amount of fuel to be injected in a short period. However, this also increases the risk of spray impingement in small-bore diesel engines. Therefore, optimizing the nozzle protrusion and spray angle to achieve appropriate spray and flame extension is crucial for complete combustion. First, the flame development characteristics of nozzle protrusions ranging from 2 to 5.5 mm were analyzed with fixed spray angles and spray impingement points, respectively. The spray impingement point was optimized by comparing the combustion quality at different spray angles. Finally, the matching of the nozzle protrusion was performed based on the corrected points. The results indicate that the flames in small-bore diesel engines possess significant
Liu, Long, Wang, Xinhao, Niu, Xiaoxiao, Wang, Yang
Multiphase Flow Simulation of Blow-by and Fuel-in-Oil Dilution via the Piston Ring Pack Using the Level-Set Method04-18-01-000309/09/2024
Modern diesel engines temporarily use a very late post-injection in the combustion cycle to either generate heat for a diesel particulate filter regeneration or purge a lean NOx trap. In some configurations, unburned fuel is left at the cylinder walls and is transported via the piston rings toward the lower crankcase region, where fuel may dilute the oil. Reduced oil lubrication shortens the oil service intervals and increases friction. Beside diesel fuel, this problem may also occur for other types of liquid fuels such as alcohols and e-fuels. The exact transport mechanism of the unburned fuel via the piston ring pack grooves and cylinder wall is hard to measure experimentally, motivating numerical flow simulation in early design stages for an in-depth understanding of the involved processes. A new CFD simulation methodology has been developed to investigate the transient, compressible, multiphase flow around the piston ring pack, through the gap between piston and liner, and its
Antony, Patrick, Hosters, Norbert, Behr, Marek, Hopf, Anselm, Krämer, Frank, Weber, Carsten, Turner, Paul
Piston and Guide-Pin Rattle Noise Mitigation in Electro-Mechanical Brake Caliper2024-01-303209/08/2024
Brake caliper commonly utilizes rubber or spring components to maintain specific clearance range for sliding characteristics, rendering them susceptible to rattle noise. The Electro-Mechanical Brake (EMB) caliper has attracted attention for its advantageous features such as reduced brake drag, optimized vehicle layout, and precise brake control. However, the inclusion of additional components related to the dry-type pressurizing system results in increased caliper weight and susceptibility to rattle noise. This study thoroughly examines rattle noise characteristics in our prototype EMB caliper, identifying primary noise sources on the piston and guide-pin sides. Implementing piston seals and guide-pin boots tightening force proves the effectiveness in improving rattle noise characteristics. Collisions between the piston and ball-screw head can be mitigated by piston inner seal, significantly reducing rattle noise. The effectiveness of the piston outer seal is limited and can be
Yoon, Boram, Jeon, Kyeong Hun, Boo, Sangpil, Shin, Choongsik, Kim, Tae Hoon
A Computational Study of Hydrogen Direct Injection Using a Pre-Chamber in an Opposed-Piston Engine2024-01-301007/02/2024
Combustion characteristics of a hydrogen (H2) direct-injected (DI) pre-chamber (PC)-assisted opposed piston two-stroke (OP2S) engine are investigated by 3D computational fluid dynamics (CFD) simulations. The architecture of the OP2S engine has potential features for reducing wall heat losses, as the DI H2 jets are not directed towards the piston face. To overcome the high resistance to autoignition of H2, a PC technology was implemented in order to enhance the ignition of the mixture by the multiple hot reactive jets. To further investigate the interaction between the H2 plume and the chamber walls, three different piston bowl designs were evaluated and ranked based on a merit function. For the cases under study, the flat piston design was found to be most favorable (compared to the narrow and wide pistons) due to its reduced surface area for lower wall heat losses. The results also showcase that a co-optimization approach considering various parameters is an effective strategy to
Menaca, Rafael, Moreno Cabezas, Kevin, Shakeel, Mohammad Raghib, Vorraro, Giovanni, Turner, James W. G., Im, Hong G.
Experimental Study of Lignin Fuels for CI Engines2024-37-002206/12/2024
This study explores the feasibility of using a sustainable lignin-based fuel, consisting of 44 % lignin, 50 % ethanol, and 6 % water, in conventional compression ignition (CI) marine engines. Through experimental evaluations on a modified small-bore CI engine, we identified the primary challenges associated with lignin-based fuel, including engine startup and shutdown issues due to solvent evaporation and lignin solidification inside the fuel system, and deposit formation on cylinder walls leading to piston ring seizure. To address these issues, we developed a fuel switching system transitioning from lignin-based fuel to cleaning fuel with 85 vol% of acetone, 10 vol% of water and 5 vol% of ignition improving additive, effectively preventing system clogs. Additionally, optimizing injection parameters, adopting a constant pressure delivery valve, and fine-tuning injection timing mitigated lignin deposit formation related to incomplete combustion or spray tip penetration to the cylinder
Terauchi, Motoki, Simonsen, Tor, Mortensen, Simon, Schramm, Jesper, Ivarsson, Anders
Influences of High-Pressure Pump and Injector Nozzle Geometry on Hydraulics Characteristics of a Mechanical Diesel Direct-Injection System2024-01-506106/04/2024
The geometry of high-pressure pump and injector nozzles crucially influences hydraulic behaviors (e.g., the start of injection, the pressure profiles developed in the high-pressure line, needle lift, and injection rates) in diesel engines. These factors, in turn, significantly impact fuel atomization, fuel–air mixing, combustion quality, and the formation of emissions. The main geometry parameters such as plunger diameter and the number and diameter of nozzles lead to the system complexity, requiring careful analysis, design, and calibration. In this study, a high-speed shadowgraph system and a high-resolution pressure recording system were developed to capture the start of injection, spray structure, and pressure profiles in the high-pressure line. Additionally, a model was developed using GT-Fuel package built within the GT-Suite of simulation tools to explore different plunger diameters and numbers and diameters of injector nozzles. These models were validated using the pressure
Nguyen, Quan Q., Vu, Manh D., Phung, Duoc V., Nguyen, Kien T., Vu*, Tuan N., Pham, Phuong X.
Evaluating the Effects of an Electrically Assisted Turbocharger on Scavenging Control for an Opposed Piston Two Stroke (OP2S) Compression Ignition Engine2024-01-238804/09/2024
Opposed piston two-stroke (OP2S) diesel engines have demonstrated a reduction in engine-out emissions and increased efficiency compared to conventional four-stroke diesel engines. Due to the higher stroke-to-bore ratio and the absence of a cylinder head, the heat transfer loss to the coolant is lower near ‘Top Dead Center.’ The selection and design of the air path is critical to realizing the benefits of the OP2S engine architecture. Like any two-stroke diesel engine, the scavenging process and the composition of the internal residuals are predominantly governed by the pressure differential between the intake and the exhaust ports. Without dedicated pumping strokes, the two-stroke engine architecture requires external devices to breathe. In the unique OP2S engine architecture studied in this work, the external pumping devices present in the air path include an electrically assisted turbocharger (EAT), an electrified EGR pump, and a back-pressure valve (BPv) located downstream of the
Bhatt, Ankur, Gandolfo, John, Huo, Ming, Gainey, Brian, Lawler, Benjamin
Combustion Analysis of Hydrogen-DDF Mode Based on OH* Chemiluminescence Images2024-01-236704/09/2024
Hydrogen–diesel dual-fuel combustion processes were visualized using an optically accessible rapid compression and expansion machine (RCEM). A hydrogen-air mixture was introduced into the combustion chamber, and a pilot injection of diesel fuel was used as the ignition source. A small amount of diesel fuel was injected as the pilot fuel at injection pressures of 40, 80, and 120 MPa using a common rail injection system. The injection amounts of diesel fuel were varied as 3, 6, and 13 mm3. The amount of hydrogen was manipulated by varying the total excess air ratio (λtotal) at 3 and 4. The RCEM was operated at a constant speed of 900 rpm, and the in-cylinder pressure and temperature at the top dead center (TDC) were set as 5 MPa and 700 K, respectively. The combustion processes were visualized via direct photography and hydroxyl (OH*) chemiluminescence photography using a high-speed camera and an image intensifier. The results indicated that the diesel mixture first ignited near the wall
Mukhtar, Ghazian Amin, Shimogawa, Koki, Horibe, Naoto, Hayashi, Jun, Kawanabe, Hiroshi, Morita, Gin, Hiraoka, Kenji
Effect of Baffle Height on the in-Cylinder Air-Fuel Mixture Preparation in a Gasoline Direct Injection Engine – A Computational Fluid Dynamics Analysis2024-01-269704/09/2024
In-cylinder fluid dynamics enhance performance and emission characteristics in internal combustion (IC) engines. Techniques such as helical ports, valve shrouding, masking, and modifications to piston profiles or vanes in ports are employed to achieve the desired in-cylinder flows in these engines. However, due to space constraints, modifications to the cylinder head are typically minimal. The literature suggests that introducing baffles into the combustion chamber of an IC engine can enhance in-cylinder flows, air-fuel mixing, and, subsequently, stratification. Studies have indicated that the height of the baffles plays a significant role in determining the level of improvement in in-cylinder flow and air-fuel mixing. Therefore, this study employs Computational fluid dynamics (CFD) analysis to investigate the impact of baffle height on in-cylinder flow and air-fuel mixing in a four-stroke, four-valve, spray-guided gasoline direct injection (GDI) engine. The maximum allowable baffle
V, Vishal, Mallikarjuna, J M
Ducted Fuel Injection: Confirmed Re-entrainment Hypothesis2024-01-288504/09/2024
Testing of ducted fuel injection (DFI) in a single-cylinder engine with production-like hardware previously showed that adding a duct structure increased soot emissions at the full load, rated speed operating point [1]. The authors hypothesized that the DFI flame, which travels faster than a conventional diesel combustion (CDC) flame, and has a shorter distance to travel, was being re-entrained into the on-going fuel injection around the lift-off length (LOL), thus reducing air entrainment into the on-going injection. The engine operating condition and the engine combustion chamber geometry were duplicated in a constant pressure vessel. The experimental setup used a 3D piston section combined with a glass fire deck allowing for a comparison between a CDC flame and a DFI flame via high-speed imaging. CH* imaging of the 3D piston profile view clearly confirmed the re-entrainment hypothesis presented in the previous engine work. This finding suggests that a DFI retrofit for this
Svensson, Kenth, Fitzgerald, Russell, Martin, Glen
Validation of a Two-Parameter Controlled Novel Tribometer for Analysing Durability of Piston Ring-Engine Cylinder Tribo-Pair2024-01-206704/09/2024
The wear of the piston ring-cylinder liner system in gasoline engines is inevitable and significantly impacts fuel economy. Utilizing a custom-built linear reciprocating tribometer, this study assesses the wear resistance of newly developed engine cylinder coatings. The custom device offers a cost-effective means for tribological evaluation, optimizing coating process parameters with precise control over critical operational factors such as normal load and sliding frequency. Unlike conventional commercial tribometers, it ensures a more accurate simulation of the engine cylinder system. However, existing research lacks a comprehensive comparative analysis and procedure to establish precision limits for such modified devices. This study evaluates the custom tribometer's repeatability compared to a commercial wear-testing instrument, confirming its potential as a valuable tool for advanced wear testing on engine cylinder samples. The validation tests, achieved through standardized contact
Sediako, Dimitry G., Banerjee, Siddharth
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