Engine Head Research Articles

High-speed nonlinear dynamic analysis of dual springs system considering internal structural impact

The significant dynamic responses of helical springs are widely reported as the main reason causing pre-failure in various high-speed conditions. Though the concept of nonlinear springs is proposed to reduce their own dynamic responses, they are found to induce unexpected spike forces during operations. This study presents a dual springs system used within high-speed sports car engines, which aims to mitigate the dynamic responses and spike forces. Analytical models are first developed to calculate the fundamental frequencies of the outer and the inner springs of the system. Then, a transient finite element (FE) model is developed to accurately simulate the dual springs system working at various high engine speeds and validated experimentally by the results of the engine head tests. The simulations reveal that the use of dual springs with different natural frequencies can mitigate the dynamic responses of the whole system to a certain extent. Nevertheless, it is still a compromise as coil clash occurs on each isolated spring though the effects are reduced. The findings of this study indicate that the establishment of direct connections between every component spring would be a promising way to better mitigate the dynamic responses including the effects of coil clash.

Effects of dual-spark ignition system with two different piston bowl shapes on combustion and efficiency in a single-cylinder engine

In this study, a dual-spark ignition system was systemically evaluated in a single-cylinder engine. Since the test engine was originally based on the diesel engine, two sparks were located symmetrically on the left and right, with the diesel injector in the middle of the engine head. At first, the effect of dual-spark ignition on the combustion process was compared with the single-spark (only right used) condition under 1600 rpm/gIMEP 0.7 MPa. Also, varying excessive air ratios were evaluated for the two conditions. The second experiment changed the piston bowl shape from (a Mexican) hat to a flat (bathtub-shaped) for the dual-spark ignition system under five representative operating conditions. Also, the maximum load was verified under a knocking frequency of 30%. The results emphasized that dual-spark ignition showed superb CoV of net indicated mean effective pressure (nIMEP) as 2.71% under excessive air ratio 1.55 condition, while it was higher than 5% with single-spark ignition. In addition, the net indicated thermal efficiency was 37.33%. Also, when flat bowl-shaped piston was used with dual-spark ignition system, the maximum load with avoidance of severe knocking could be increased from nIMEP 1.07 to 1.44 MPa due to enhancing flame propagation speed.

Sustainable and Novel Development of Metal Matrix Composite Using Scrap Aluminium Alloy Reinforced with Scrap Borosilicate Glass Particles by Stir Casting Technique

This study aims to achieve a sustainable and environmentally friendly approach to the development of metal matrix composites (MMCs) by utilizing locally available Scrap Aluminium Engine Heads (SAEH) as the matrix material and powdered Scrap Borosilicate Glassware (SBG) as reinforcement. The stir casting technique was employed for composite fabrication, combining the benefits of cost-effectiveness and ease of processing. The research evaluates the mechanical properties of the developed MMC, including tensile strength, compressive strength, hardness, and impact resistance. Physical properties such as density and porosity were also investigated, alongside microstructural analysis using optical microscopy, scanning electron microscopy (SEM), SEM energy-dispersive X-ray analysis (EDAX), and X-ray diffraction (XRD). The results demonstrate a significant improvement in the mechanical properties of the composite compared to the as-cast SAEH material. The ultimate tensile strength increased from 70.3 MPa for as-cast SAEH to 117.3 MPa for SAEH reinforced with SBG. Similarly, ultimate compressive strength improved from 513.7 MPa to 700.67 MPa, and hardness increased from 32.56 HRB to 43.33 HRB. Furthermore, the impact strength showed a notable enhancement, increasing from 1.4 Joules to 1.8 Joules. Importantly, the porosity percentage decreased from 14.28% in as-cast SAEH to 9.97% in SAEH+BS composites, indicating improved material density. This research contributes to the development of sustainable MMCs using recycled materials, offering enhanced mechanical properties and reduced environmental impact, making it valuable for various engineering applications. By aligning with Sustainable Development Goals (SDGs), this study addresses key sustainability targets and underscores the importance of environmentally responsible materials development in advancing global sustainability efforts.

Comparative Assessment of Head Deposition, Exhaust Gas Temperature and Sound Emission in CI Engine using Blend Fuel

Energy has a significant role in the socio-economic growth for any country. The energy originates from fossil fuels, which are non-renewable and enact an undesirable impact on the environment. Waste cooking oil can be utilized in diesel engine directly. Preheating and trans-esterification process are expensive to convert waste cooking oil into biodiesel. This research aims to replace diesel with waste cooking oil as binary blend and compared with diesel fuel. Engine testing at the constant speed of 1300 rpm at constant load. This study revealed that, addition of waste cooking oil reduced exhaust gas temperature as compared to base line fuel. In case of noise emission, sound level for emulsion fuel DF95WCO5 was reduced compared to DF. In this study, a single-cylinder CI engine was run for 200 hours on two fuel samples: DF (diesel fuel) as the baseline fuel and DF95WCO5 (5% waste cooking oil and 95% DF). During the endurance test, the effects of DF95WCO5 on engine head deposits were studied. According to the investigation's findings, visual inspection of both fuel samples revealed some deposit buildup on injectors. SEM (scanning electron microscopy) and EDX (energy dispersive X-ray spectroscopy) analysis revealed that the engine running with DF95WCO5 formed more carbon deposits on and around the head. It can be concluded that binary emulsion can be used in compression ignition engine without any engine alterations. Consequently, WCO can be proficiently used to reduce detrimental effects and reduce fossil fuel dependency.

Stress mitigation of a thermal engine head block using the bioinspired BGM-FEM method

Structural optimization plays a pivotal role in the design and development of engine heads, as it directly affects the performance, efficiency, and durability of internal combustion engines. In this paper, we propose a novel approach for the thermo-structural optimization of the internal surfaces of the engine heads, using the Biological Growth Method (BGM). The BGM is a bio-inspired technique that mimics the growth patterns observed in some biological organisms, able to achieve superior structural efficiency thus generating optimal designs. The effectiveness of the BGM methodology, coupled with mesh morphing techniques based on Radial Basis Functions (RBF), is in this work demonstrated for several districts, effectively reducing material usage and enhancing structural performance.

President’s Column: The Importance of Supporting Academia and Students in Navigating the Challenges and Opportunities in the Industry

Editor’s Note: This is a summary of the May episode of the President’s podcast. We encourage you to listen to the episode to hear the full conversation. In this podcast episode, I am joined by Jennifer Miskimins, department head of petroleum engineering at the Colorado School of Mines, to discuss the importance of supporting universities and students through the challenges and opportunities facing the industry. I chose Jennifer to be part of this episode because of her extensive experience in both academia and the industry. This episode aims to delve into the status of petroleum engineering departments and the importance of students in shaping the industry’s future. I emphasize the collaborative effort required from universities, SPE, and its members to attract the next generation to the field. Our conversation revolves around the importance of addressing the challenges faced by petroleum engineering programs and attracting students to the field. I explain that the SPE Board of Directors recognizes the significance of universities, students, and faculty in the industry, including naming them as core constituencies in SPE’s Strategic Plan. Attracting the next generation is one of the top concerns among SPE members. Young professionals and students play a vital role in driving innovation and addressing future challenges, emphasizing the need for a full pipeline of talent to sustain the industry’s progress. I believe that students are essential for shaping the future of energy and fulfilling humanity’s needs, as they aspire to make a meaningful impact in the world. We need the next technical breakthroughs, most of which will come from the students in university today. They want to feel like they’re making a difference in the world. Jennifer adds, “What I frequently hear from students is yes, they want a long-term career but making a difference is very important. And they can do so. So hopefully, we can get more students coming our direction.” Although enrollment in petroleum engineering programs has fluctuated due to industry downturns and external factors like the COVID-19 pandemic, recent data suggests a modest increase in undergraduate enrollment, indicating a potential upswing. There are challenges such as the industry’s public image, perception of job stability, and declining enrollment in STEM education. Addressing these challenges requires reframing the narrative around the energy “transition” to one of “expansion” and highlighting the long-term career opportunities in the industry. We share insights into how universities are incorporating diverse energy-related topics into their curriculum, offering electives on emerging technologies, and engaging with industry professionals to provide students with real-world insights and opportunities. We also emphasize the role of faculty advisors and industry support in sustaining student chapters of organizations like SPE, which play a crucial role in bridging the gap between academia and industry. We further point out the critical role SPE members play in supporting students and universities through mentorship, financial support, and speaking engagements. Active involvement in student chapters helps bridge the gap between academia and industry.

Beware of the abuse of AI-powered algorithms!

Head of Computer Engineering (English) Department Prof. Burhan Pektaş evaluated the issue of whether artificial intelligence can interfere with people's lives.

Robotic additive manufacturing by laser metal deposition in the context of industry 4. 0

The integration of a KUKA robot with a Meltio Engine head to create a laser metal deposition by wire (LMD-wire) cell involves a meticulous installation and must be highly controlled to function with the required precision. To this end, the creation of a digital twin became essential to operate the cell and to generate data that enable its monitoring, through an artificial intelligence system that optimizes its performance and prevents equipment wear. The goal of this article is to present the research that the Industrial Automation Innovation Group at the University of Brasília has been developing. The procedures are detailed, such as the installation of the robot, the Meltio-KUKA integration, the elaboration of a planar slicer with Rhino3D-Grasshopper and the simulation process with KUKA.Sim. The simulations’ results confirmed the robustness of the system for planar deposition methods and demonstrated its versatility to adapt to non-planar, multiplanar and hybrid deposition methods. The integration of the LMD-wire cell will remain under evaluation until its complete installation, when it will be ready for the first deposition experiments.

Preliminary assessment of the potential for rapid combustion of pure ammonia in engine cylinders using the multiple spark ignition strategy

In pursuit of carbon neutrality, the adoption of zero-carbon fuels in internal combustion engines offers a path to zero carbon emissions. Among such fuels, ammonia (NH3) stands out as an effective hydrogen energy carrier with a higher energy density and a more advanced production-storage-transportation lifecycle than hydrogen (H2) fuel, making it a superior alternative. Nevertheless, achieving high combustion efficiencies in engine cylinders requires the use of fuels with fast flame speeds, since the time scales of the combustion event are practically milliseconds. The inherent flame speed of NH3 falls short, typically necessitating augmentation with H2. Yet, the in-situ generation of H2 from NH3 remains constrained, rendering the flame speed of NH3 less competitive against traditional fuels like gasoline and natural gas. To address the dual challenges of slow flame speed of NH3 and the difficulty of generating large amounts of H2 from NH3 onboard, this study evaluates an alternative method of accelerating the ammonia combustion in the engine combustion chamber through the use of multiple spark plugs, which is limited discussed in existing research. Numerical simulations performed in this study show that the application of the multi-spark strategy increases the mass burn rate, advances the combustion phasing, shortens the combustion duration, increases the engine power output, improves the fuel economy, and reduces the unburned ammonia emissions, all of which indicate that rapid combustion of pure ammonia is achieved in the combustion chamber. Moreover, the use of multiple spark points does not lead to a marked increase in nitrogen oxides emissions, thereby ensuring no added stress on exhaust aftertreatment systems. In addition, pure ammonia combustion appears to be very well adapted to this strategy, as evidenced by the avoidance of excessive cylinder pressures and pressure rise rates—a challenge faced by conventional spark ignition engines, given ammonia notably slower flame speed relative to conventional petroleum-based fuels. Overall, all these findings strongly support that the multi-spark ignition system presents a compelling direction for future zero-carbon ammonia engines. However, it is crucial to address design challenges to ensure that the engine head layout provides sufficient cooling, structural robustness, optimal breathing efficiency, and reliable multi-ignition events within the confined space.

The Evolution of the Sustainable, Intelligent City

Abstract Grant Powell MBCS spoke to Professor Julie McGann, Head of the Adaptive Emergent Systems Engineering (AESE) group at the Imperial College London's Department of Computing to discuss how data-driven insights can help to develop greener, cleaner cities.

An analytical approach to converting vibration signal to combustion characteristics of homogeneous charge compression ignition engines

Homogeneous charge compression ignition (HCCI) is a promising low-temperature combustion technique for low-emission internal combustion engines. Unlike conventional engines, HCCI lacks a direct ignition control mechanism, necessitating closed-loop combustion control. This study proposes a phenomenological-based, cost-effective, and non-intrusive approach using vibration data analysis to determine essential combustion parameters. Experiments were conducted on a single-cylinder research engine with an accelerometer attached to the engine head. The engine operation envelope covered the whole engine’s operating area in naturally aspirated HCCI mode. Wavelet analysis revealed that combustion-related frequencies centered around 500 Hz, independent of operating conditions. The correlation-seeking analysis included peak acceleration amplitude and its crank angle with peak heat release rate (HRR) data. The peak HRR location was accurately identified within one degree when vibration amplitude exceeded the 100 m/s2 threshold. This encompassed 98.5% of the analyzed combustion cycles. The peak HRR prediction accuracy had a maximum error below 21% and was suitable to monitor reaction rates, especially in incomplete combustion and high ringing cycles.

Sustainable development on production and characterization of metal matrix composites using stir casting

In this study, four different combinations of aluminium metal matrix composites (AMCs) were produced using a computerized stir casting process. The feasibility of using car Scrap Aluminium Engine Head (SAEH) as matrix material, Fresh Alumina Catalyst (FAC) and Spent Alumina Catalyst (SAC) from petrochemical industries as reinforcement material were investigated. The physical and mechanical properties of the cast samples were tested through density, hardness, tensile, compression, and impact test. Microstructural investigations were carried out using an optical microscope, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Differential thermal analysis (DTA) and Thermo gravimetric analysis (TGA) were also conducted to justify the results obtained. The results indicated that SAEH reinforced with 5 wt% SAC exhibited lower porosity (2.6%) and higher Brinell hardness (71.5 BHN), Vickers hardness (307.1 VHN), tensile strength (217 MPa), and compressive strength (426 MPa) than other composites. Additionally, this composite showed the highest impact strength (0.02375 J mm−2) and DTA value (568.5 μV mg−1). The TGA result showed that all composites had high thermal stability, with the SAC-reinforced composites having the highest thermal stability (100.13%).

Investigation of In-Cylinder Pressure Measurement Methods within a Two-Stroke Spark Ignition Engine

<div>This work describes an investigation of measurement techniques for the indicated mean effective pressure (IMEP) on a 55 cc single-cylinder, 4.4 kW, two-stroke, spark ignition (SI) engine intended for use on Group 1 and Group 2 remotely piloted aircraft (RPAs). Three different sensors were used: two piezoelectric pressure transducers (one flush mount and one measuring spark plug) for measuring in-cylinder pressure and one capacitive sensor for determining the top dead center (TDC) position of the piston. The effort consisted of three objectives: to investigate the merits of a flush mount pressure transducer compared to a pressure transducer integrated into the spark plug, to perform a parametric analysis to characterize the effect of the variability in the engine test bench controls on the IMEP, and to determine the thermodynamic loss angle for the engine. The results indicate that as a spark plug, the measuring spark plug is not statistically different from the stock spark plug at the 95% confidence level. The results indicate a statistically significant, 4% difference in the measured IMEP between the pressure transducer in the measuring spark plug and the flush mount transducer. The results also suggest a statistically significant difference in performance between the modified and unmodified engine heads, verifying the suppositions of other researchers who suggested that even a small modification to a combustion chamber this size could measurably affect the engine performance. While run-to-run variation resulted in a 2% to 5% variation in IMEP, a sensitivity analysis determined that 1% to 3% of that variation arose from variability in the control variables, while the remainder was caused by variation in other engine operating parameters. Between 1000 rpm and 2000 rpm, where the engine was typically motored to determine the TDC, the thermodynamic loss angle was 0.3 crank angle degrees (CAD) to 0.7 CAD, larger than loss angles observed in automotive-sized gasoline engines. The results indicate that using tabulated thermodynamic loss angles to set the TDC location of the engine using a mono-directional peak pressure method would lead to a −1% to −2.5% bias in the IMEP.</div>

Vibration Distribution Measurement of Car Door and Engine Head Using OPPA Vibration Distribution Analyzer

In order to address the issue of vibration, it is crucial to accurately measure the vibration distribution. The authors previously developed the one-pitch phase analysis (OPPA) method, which allows for rapidly capturing the three-dimensional shape of a flat object. By integrating this method into a system, an OPPA vibration distribution measurement system was created, utilizing a line light source consisting of LEDs or optical fibers and also a high-speed camera to measure the vibrations of three-dimensional objects without physical contact. To further extend the application of the OPPA method to larger objects, such as cars, in this paper, a new system is introduced using a commercially available projector using a liquid crystal display (LCD) instead of a liner light source and a glass grating. This new system, which employs an ultra-short throw projector, is highly sensitive in displacement measurements and provides a wide-area analysis. These kinds of projectors produce noises at the frequency of the cooling fan and the refresh rate of the LCD. However, in this study, these noise sources were also examined. The capabilities of the new system are demonstrated through its application to the measurement of vibrations in a car door and an engine head. The measurement system and examples of its application are presented.

Dynamic Finite Element Model Based on Timoshenko Beam Theory for Simulating High-Speed Nonlinear Helical Springs

Helical springs with nonlinear geometric parameters nowadays have shown great advantages over classical linear springs, especially due to their superior performance in diminishing dynamic responses in high-speed situations. However, existing studies are mostly available for springs with linear properties, and the sole FE spring models using solid elements occupy significant computational resources. This study presents an FE spring model based on Timoshenko beam theory, which allows for high-speed dynamic simulations of nonlinear springs using a beehive valve spring sample. The dynamic results are also compared with the results of the FE model using solid elements and the results of the engine head test and indicate that the proposed FE model can accurately predict dynamic spring forces and the phenomenon of coil clash when simulating the beehive spring at engine speeds of both 5600 and 8000 RPM. The results also indicate that rapid coil impact brings significant spike forces. It should also be noted that the FE spring model using beam elements displays sufficient accuracy in predicting the dynamic responses of nonlinear springs while occupying much fewer computational resources than the FE model using solid elements.

Investigative Studies on Performance Behavior on an IDI diesel engine with a Geometrically Modified Swirl Chamber using Biodiesel Blends

In this experimental study, combustion, performance and emission characteristics of conventional swirl chamber (CSC) and geometrically modified swirl chamber (GMSC) of IDI diesel engines were studied. A GMSC was designed and fabricated in a separated engine head, for performance testing and comparison purpose. Biodiesel from chia seed oil was extracted by transesterification process and blended with diesel based on volumetric ratios of 5% to 25%, in steps of 10% increase. The performance and emission characteristics of biodiesel blends were compared with petroleum diesel using the CSC and GMSC. The result shows BTE of biodiesel blend BC05, BC15 and BC25 using the GMSC are 3.18%, 0.21% and 1.19% lesser compared to CSC 75% load. In-cylinder pressure of blends BC05, BC15 and BC25 are 66.3 bar, 59.04 bar and 54.34 bar with GMSC. BSFC of BC05, BC15 and BC25 with GMSC are 2.56%, 9.38% and 11.95% higher compared to diesel due to the low CV of biodiesel. NOx emissions for diesel, BC05, BC15 and BC25 are 9.47%, 18.41%, 6.98% and 1.67% respectively less at 75% load with GMSC compared to CSC. From the performance and emission characteristics blend B15 may be recommended as a promising substitute for petroleum diesel.

Evaluation of the rate of heat release of Polanga-based biodiesel and ethanol in the modified dual-fuelled mild steel engine and copper coated piston and engine head arrangement

By evaluating the technical viability and projecting biodiesel and ethanol as prospective alternate fuels, the emphasis is placed on realising the global goal of looking for alternative fuels to have energy security. The current mild steel engine has been updated, as described, to provide effective output with dual fuel. The summary of the suggested alterations and performance improvements are examined based on the study of experimental findings and literature review. A direct injection (DI) low-speed diesel engine with a rated output of 3.5 kW when fueled with diesel fuel was used for the experiment. During the experiment, the DI diesel engine was first run in single and dual fuel modes with diesel/biodiesel at 0 %, 50 %, and 100 % of the rated load and 10 %, 20 %, and 30 % of ethanol as the primary fuel. The lab contained all of the technological parameters. In the studies, it was discovered that for all fuel combinations, the peak heat release decreased with dilution and increased with load. Dual fuel mode combustion had somewhat greater ignition delays for both diesel and biodiesel than single fuel mode combustion. Because neat diesel ignites more quickly than biodiesel with ethanol, it releases more heat at its peak, making engines with copper-coated pistons and engine heads safer.

Peak pressure analysis for modified mild steel DI diesel engines with copper-coated pistons and engine heads under dual fuel injection mode

The current study assesses the impact of ethanol injection using a secondary injection system on thermal efficiency and engine combustion pressure. To enable observations to be made at each operating point in a progressive increasing or decreasing order, all sets of operating conditions chosen for the experiment are structured in a sequence. The engine's dual fuel mode allows it to run on various concentrations of ethanol using a separate injection system. In this experiment, the engine ran on various ethanol blends of 10%, 20%, and 30% in addition to the basic gasoline. An increase in the peak pressure with load for all fuel combinations and a decrease with dilution except at 50% load is observed in the experiments. In addition, both the oils in dual fuel mode give maximum peak cylinder pressure after the TDC, which is encouraging. The highest peak pressure of 61.21 bar at 363.53°CA, obtained with biodiesel and ethanol is less than that of neat diesel as 65.95 bar at 364.85°CA, creating no danger to the engine structure which is made of Mild steel with a copper-coated piston and cylinder head arrangement. With the increase in ethanol substitution, an improvement in efficiency is recorded for biodiesel at all loads. In addition, for the same ethanol content, biodiesel gives higher BTE than diesel under similar loading conditions. It is observed that ethanol addition has an almost similar effect on both diesel and biodiesel at all loads.

Development of technology for high-strength cast iron for manufacturing D49 head of cylinder

This article discusses the technology of melting high-strength cast iron with a spheroidal graphite shape intended for the D-49 type cylinder lid by modifying with magnesium (Mg) in the ladle and gating systems. Today, it is very important for the Republic of Uzbekistan and the CIS countries to create and improve high-strength cast iron production technology to prepare high-responsibility parts of railway transport. Improvement of the mechanical and operational properties of cast iron parts with high strength, as well as development and improvement of the casting technology of the D49 type diesel engine head imported from the CIS countries under local conditions.

Investigation of Bio-Diesel in Uncoated Piston Head Vs Bio-Diesel in Coated Head

The need for less carbon content in fuel, as well as an increase in energy consumption, has paved the way for the development of alternative fuel for engines. Biodiesel is an environmentally friendly alternative to conventional fuel. Thermal barrier coating reduces heat transfer to the cooling system while the engine is idle and protects engine components from high thermal stresses. This paper investigates the blending of waste fish fry methyl esters in a single cylinder, four stroke DI diesel engine with a stellite-6 coated engine head. In this study, waste fish fry oil (WFFO) was transesterified with methanol and a NaOH catalyst. The methyl esters were obtained, and various test fuels were made (WFFO10, WFFO20, WFFO30) These blended samples were fired up in the DI diesel engine, and performance tests were conducted. Engine characteristics such as brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and engine emissions were measured for the stellite6 coated cylinder head.