Cylinder Head Research Articles

Improving the Efficiency of Spark-Ignition Internal Combustion Engine Using a Novel Electromagnetic Actuator and Adapting Increased Compression

This paper presents an empirical study of a spark-ignition internal combustion engine with modifications made to increase its effectiveness. The modification was implemented bi-directionally in terms of changes to the compression ratio and changes to the engine’s valve train. The compression ratio was increased by 2.3 units by design and a hybrid intake valve opening control was used in the engine’s valve train. The hybrid control involved autonomous control of one of the inlet valves with a dedicated electromagnetic actuator. The designed electromagnetic actuator was mounted downstream of the single-cylinder engine’s intake system’s modified camshaft to control the effective compression pressure build-up. Field calculations were carried out for the electromagnetic actuator’s design variants and its current characteristics were determined. The multivariate calculations were carried out in order to find the quasi-optimal geometry of the actuator. The width and height of magnetic field coils and the dimensions of the stator poles were changed, while maintaining the same external dimensions of the actuator to enable its mounting in the cylinder head system. In the next step, the prototype of the actuator was made and placed on the combustion engine in order to conduct the experimental investigations. The work was aimed at improving the internal combustion engine’s efficiency at the low load range, as this is load range in which it has low efficiency despite it being the most often used during normal vehicle operation. The original measurement stand was prepared, and many tests were carried out in order to investigate the influence of the electromagnetic valve on the combustion engine characteristic. This improved the internal combustion engine’s efficiency at its low-load range by up to 25%. Both calculation and measurement results are presented in form of graphs.

The Effect of Ceramic Coating on Performance and Emission of Diesel Engine Operated on Diesel Fuel and Biodiesel Blends

In this work, the effect of ceramic coating on performance, exhaust gas temperature and gases emissions of diesel engine operated on diesel fuel and biodiesel blends was investigated. A conventional four stroke, direct injected, single cylinder, diesel engine was tested at constant speed and at different load conditions using diesel fuel and biodiesel blends. The inlet and exhaust valves, the head of piston and cylinder head of the engine were coated by ceramic materials. Ceramic layers were made of (210-240) μm of Al2O3 and (30-60) μm of 4NiCr5Al as a bond coat for inlet and exhaust valves and (350-400) μm of YSZ and (50-100) μm of 4NiCr5Al as a bond coat for head of piston and (280-320) μm of Sic and (40-80) μm of 4NiCr5Al as a bond coat for cylinder head. The coating technique adapted in this work is the flame spray method. The engine with valves, piston and cylinder head ceramic coated research was tested for the same operation conditions of the engine (without coating). The results showed that a reduction in brake specific fuel consumption of 19.29%, 15.91%, 14.65% and 7.06%, an increase in brake thermal efficiency of 23.68%, 19.77%, 16.51% and 6.32%, the increase in exhaust gas temperature of 9.01%, 7.22%, 15.7% and 11.42%, the reduction of CO emission of 18.57%, 20%, 20.5% and 27.77%, the reduction of HC emission of 28.97%, 43.9%, 38.88% and 36.41% for diesel, B5,B10 and B100 respectively.

Optimization of biodiesel production, engine exhaust emissions, and vibration diagnosis using a combined approach of definitive screening design (DSD) and artificial neural network (ANN).

In this study, definitive screening design (DSD) optimization and artificial neural network (ANN) modelling techniques are applied for the production of palm oil biodiesel (POBD). These techniques are implemented to examine the vital contributing factors in achieving maximum POBD yield. For this purpose, seventeen experiments are conducted randomly by varying the four contributing factors. The results of DSD optimization reveal that a biodiesel yield of 96.06% is achieved. Also, the experimental results are trained in ANN for predicting the biodiesel yield. The results proved that the prediction capability of ANN is superior, with a high correlation coefficient (R2) and low mean square error (MSE). Furthermore, the obtained POBD is characterized by significant fuel properties and fatty acid compositions and observed within the standards (ASTM-D675). Finally, the neat POBD is examined for exhaust emissions and engine cylinder vibration analysis. The emissions results confirm a significant drop in NOx (32.46%), HC (40.57%), CO (44.44%), and exhaust smoke (39.65%) compared to diesel fuel at 100% load. Likewise, the engine cylinder vibration measured on top of the cylinder head reveals a low spectral density with low amplitude vibrations observed for POBD at measured loads.

Experimental and analytical studies on a novel steel-PU foam-concrete-tube multilayer energy absorbing panel under impact loading by a cylinder head

A novel steel-polyurethane foam-concrete-tube multilayer energy absorbing panel (SFCTMEAP) was proposed in this paper, and it could be attached to the surface of the protected structure to mitigate impact loading. The impact tests on the SFCTMEAP were performed via using a drop-weight impact test machine. The investigated parameters in the impact tests included the thickness of concrete core as well as thickness and width of the steel tube. All tested specimens exhibited a combined failure mode, consisting of the local indentation of energy absorbing panel and the collapse of polyurethane foam-filled steel tubes. The energy absorbing performance of SFCTMEAP under impact loading was discussed in detail. Additionally, a three-degree-of-freedom model was proposed to obtain the displacement response of the SFCTMEAP, and the analytically-calculated displacement–time histories agreed well with the experimental results.

Investigations on performance parameters of carburetted butanol and plastic oil

As fuel prices continue to rise and pollution levels caused by fossil fuels escalate, there is a growing recognition of the importance of alternative fuels. Alcohols and vegetable oils are particularly promising as substitutes for diesel fuel due to their renewable properties. However, both vegetable oils and alcohols have certain drawbacks, such as high viscosity and low volatility for vegetable oils, and low energy content and Cetane number for alcohols. To address these challenges, the use of semi-adiabatic diesel engines (SADE) has been proposed. In this study, the focus was on evaluating the performance characteristics of both a conventional engine (CE) and a semi-adiabatic diesel engine (SADE). The engines were powered by a combination of carbureted butanol and injected plastic oil, leveraging the high energy content of plastic oil and the high volatility of butanol to achieve lower pollution levels. The objective was to assess the effectiveness of these engines in mitigating environmental impact The experimental engines utilized carbureted butanol and injected plastic oil, with variations in injection timing and pressure. The engine used in the study was a water-cooled, single-cylinder, four-stroke engine with a ceramic-coated cylinder head. It had a rated output of 3.68 kW at 1500 rpm. Measurements of various engine parameters, including thermal brake efficiency, brake specific energy consumption, exhaust gas temperature, coolant load, and volumetric efficiency, were conducted under full load conditions. To modify the injection timing, an adjustable sensor was employed, while a variable jet carburetor mounted at the engine's inlet manifold controlled the rate of carbureted butanol. Injection pressure was adjusted using a spout testing instrument, and conventional injection was utilized for the crude plastic oil.

Research on fatigue reliability assessment of engine cylinder head based on neural network

Fatigue reliability (FR) evaluation is crucial for extending the service life and improving the reliability of automotive engines. This study proposed a general framework for assessing high cycle FR based on the back propagation neural network (BPNN). Using a diesel engine cylinder head (CH) as an example, the stochastic finite element analysis was implemented by considering the uncertainties of materials and loads. Subsequently, the stochastic finite element calculation process was replaced with the BPNN model to expedite fatigue life prediction. Ultimately, the reliability assessment of the CH was conducted, taking into account the influence of the load sequence. The research findings indicated that the reliable life t0.95 of the CH considering the load sequence was approximately 75 h, representing a 7.1% increase compared to the linear cumulative damage. During the service life of the CH, the failure probability sensitivity factor for the gas force load exceeded 0.9, offering an important reference for optimizing FR.

The effect of intake port shape on in-cylinder flow field and turbulence distribution in a high-tumble production engine with endoscope accesses

Three cylinder heads with varied intake port shapes are experimentally investigated to evaluate intake flow structures and their influence on near top dead centre (TDC) flow fields and turbulence distributions in a motored high-tumble engine. The endoscopic high-speed particle image velocimetry (eHS-PIV) is implemented in multi-cylinder engines with two laser endoscopes and a camera endoscope installed in the cylinder head. For a range of engine load and speed conditions, particle seeded and laser illuminated high-speed movies are recorded for 100 cycles with which ensemble-averaged flow fields and spatial-filtered high-frequency flow magnitude distributions are analysed. The results show that a straighter intake port producing a more lateral flow direction results in a larger swinging arc, which is related to enhanced flow later in the compression stroke. The tumble vortex shows an asymmetric structure; the flow field during the compression stroke exhibits higher magnitude vectors at the leading head. This surging flow head becomes stronger with a straighter intake port, which leads to enhanced tumble vortex formation near TDC. As it becomes very strong, the flow vectors originally directed towards the exhaust valves bounce back towards the intake valves, causing a very complex flow structure involving multiple flow components. The result is enhanced turbulence throughout the late compression stroke including the spark timing. However, the impact of the straighter intake port shape on TDC turbulence becomes less significant at lower engine load and speed conditions as the lower intake air momentum limits the enhancement.

Experimental study on wall heat transfer from diesel spray flame in two-dimensional combustion chamber operated with rapid compression and expansion machine (RCEM)

Heat transfer phenomenon in internal combustion diesel engine is one of problems to be solved. This study was conducted to investigate the relationship between diesel spray impingement, combustion processes, and heat loss using a rapid compression and expansion machine (RCEM). Furthermore, spray combustion and heat transfer processes were investigated using multiple injection strategies with a 6-holes injector. The amounts of diesel fuel used in the pilot, pre-injection, and main injection sprays were 3.964, 0.747, and 11.205 mg, respectively. Variations in common rail pressure conditions (30, 120, and 180 MPa) were applied to properly investigate spray evaporation, air–fuel mixture formation, and heat transfer in the combustion chamber. In addition, a local wall heat flux sensor was installed in the cylinder (head and liner) and piston cavity (upper lip, lip, and bottom) to measure the heat flux distribution, and a diffused backlight illumination method was used to visualize the spray and flame behavior in the combustion chamber and 2D piston cavity. The results showed that the impingement flame surrounding the cylinder head contributed to the highest magnitude and longest duration of the heat flux on the cylinder side owing to the spray flame velocity, impingement, and residence time. Meanwhile, the highest different temperature at cavity bottom induced more heat flux on the cavity side than that on the squish side. In addition, the higher injection pressure increased the spray momentum and spray tip penetration which led to a better air–fuel mixture, better evaporation rate, and less flame residence that contributed to reduce the accumulated heat loss in combustion chamber. Furthermore, a low common rail pressure was found to induce a greater difference in the accumulated heat flux ratio than a high common rail pressure which is owing to longer flame residence time in the combustion chamber. They were approximately 14% and 6% greater than that compared to the baseline common rail pressure which mean that a high common rail pressure contributes for the improving thermal efficiency in spray combustion.

An Experimental Investigation of the Effects of Diesel-Ethanol Blends on the Noise and Vibrations of a Diesel Engine

This study performed a noise and vibration analysis of a single-cylinder diesel engine with 5, 10, and 15% ethanol concentration in diesel fuel at 20, 40, 60, 80, and 100% load and a constant engine speed of 1500rpm. Vibrations were measured at the cylinder head in the horizontal, vertical, and axial directions. The frequency and octave spectrums were obtained using an FFT analyzer. The results revealed that the E5D95 blend had significantly less vibration and noise than the E10D90 and E15D85 blends. The vibration level was minimum at 20% load and maximum at 100% load in the vertical, horizontal, and axial directions, while the highest noise level was observed for E15D85.

Comparative evaluation based on FEA of thermal analysis of IC engine cylinder using different materials

Because it seals the working ends of the cylinder and houses a combustion chamber, as well as a spark plug and valves, the cylinder head is an important component of an IC engine. The heat created in the combustion chamber is very dynamic, allowing just a few microseconds to transmit the heat, which if not dispersed will cause the piston to squeeze due to overheating. As a result, excellent waste heat distribution through the cylinder body is critical to the IC engine's smooth operation. As the geometry of cylinder is problematical and the temperature within the combustion chamber is still indefinite, heat transmission through the cylinder body comprises of conduction through fins and convective heat transfer owing to surrounding air movement. Traditional heat transfer evaluation methods are quite difficult. The primary goal of this study is to examine and analyse the heat transmission of cylinder bodies constructed of various materials, including Aluminium alloy, magnesium alloy, cast iron, and stainless steel. The vehicle's speed was limited to 40 km/h, and the fin thickness was limited to 3 mm for all materials. SolidWorks is used to model the cylinder engine block with rectangular fins as well as its thermal analysis. According to thermal study results, heat dissipation is optimum in the Aluminium alloy 6061, whereas stainless steel has the least dissipation.

Availability-Oriented Maintenance Strategy of Key Equipment in Automated Production Line Considering Performance Degradation

Long-term manufacturing would bring performance degradation of key equipment in automated production lines (APLs), leading to operating unbalance and inefficiency. The existing maintenance strategies can generate maintenance schemes, but they generally ignore performance degradation that can further influence the production process. To efficiently generate maintenance schemes with maximized availability and minimized cost, an availability-oriented maintenance strategy considering performance degradation is proposed based on a synchronized hybrid optimization algorithm (SHEA) in this study. Firstly, the performance degradation of key equipment in APLs is analyzed based on the Weibull distribution, and the availability of the equipment is analyzed considering performance degradation. Secondly, a maintenance model for the key equipment in APLs is established, and a SHEA based on multi-objective particle swarm optimization (MOPSO) and squirrel search algorithm (SSA) is proposed to optimize the maintenance model with higher efficiency. Finally, the effectiveness and superiority of the proposed method are verified by citing a practical APL of the engine cylinder head as an example in the case study.

A novel multiple spark ignition strategy to achieve pure ammonia combustion in an optical spark-ignition engine

Ammonia is an attractive carbon-free fuel that has the potential to reduce the need for conventional hydrocarbons (HC) and reduce emissions of undesirable pollutants such as CO, CO2, particulates, and unburned hydrocarbons. However, ammonia has different combustion characteristics than conventional HC fuel. Ammonia is difficult to ignite and has a low combustion rate, resulting in large cyclic variations. In addition, nitrogen oxides (NOx) emissions in the exhaust tract are a major challenge when using ammonia as a fuel directly in engines. In this study, the effect of multiple spark ignition sites on the combustion of pure ammonia in an optical spark ignition engine (SI) was investigated. The experiment was conducted with four spark plugs mounted equidistantly on a special metal liner and one spark plug fitted at the top of the cylinder head. The multiple flames emitted from the different spark ignition sites were captured by natural flame luminosity (NFL) imaging. In the results, the conventional single spark ignition is compared with multiple ignitions. It was found that single spark ignition resulted in lower in-cylinder pressure, longer combustion duration, and higher combustion instability due to the poor ammonia fuel combustion rate. However, firing multiple spark plugs significantly improved combustion stability, increased engine power, and shortened the combustion period under the same operating conditions. In addition, the flame kernels produced by multiple ignition sites resulted in higher NOx emissions in the exhaust tract due to the higher temperatures in the cylinder. In addition, this study also investigated the effect of three different air–fuel equivalence ratios (λ) of 1.0, 1.2, and 1.4 on the combustion characteristics of ammonia fuel. The maximum NOx level was obtained for λ: 1.2 because the excess air in the mixture oxidizes the ammonia and provides abundant oxygen to generate more NOx. Further reducing the ammonia fuel and increasing the excess air to λ: 1.4 dramatically reduced NOx emissions due to the lower pressures and temperatures in the cylinder resulting from the longer combustion period.

Fatigue Life Prediction of Gray Cast Iron for Cylinder Head Based on Microstructure and Machine Learning

Fatigue Life Prediction of Gray Cast Iron for Cylinder Head Based on Microstructure and Machine Learning

Impact of crude palm oil on engine performance, emission product, deposit formation, and lubricating oil degradation of low-speed diesel engine: An experimental study

The higher emissions are one of the main issues associated with the use of diesel power plants. Therefore, various previous studies have been conducted on the substitution of diesel with renewable base liquid fuels for internal combustion engines, such as Crude Palm Oil (CPO). In this study, a comprehensive evaluation was carried out on the impact of using CPO on a low-speed diesel engine with a large capacity. The objective of this study is to determine the viability of modifying the existing diesel engine to operate on CPO fuel, with the aim of minimizing the requirement for additional capital expenditures. Furthermore, a diesel power plant engine with a rated capacity of 2554 kW and a rated speed of 600 RPM using a modified injector was employed. The testing phase was divided into two stages namely, a performance test for 7 h and a running test for 375 h. During the running test, the level of emission was also tested with different load variations using a portable flue gas analyzer. Following this, the lubrication oil sample was collected both before and after the engine running test. The deposits sample obtained from the engine was analyzed using SEM-EDX. Prior to being introduced into the engine, the fuel pre-treatment plant ensured that the kinematic viscosity and temperature of the CPO were properly maintained. The results show that operating the low-speed diesel engine with the continuous use of 100% CPO is not recommended due to the reducing of the engine gross power, the peak combustion pressure, the engine's IHP (indicated horse power) and the exhaust temperature of each cylinder. Furthermore, deposits were found on the cylinder head, piston, valve, and nozzle. Besides, the lubricating oil quality also degraded. Therefore, necessary to conduct a comprehensive study on the technical and financial aspects of using other biofuels that have a minimal risk impact on engine reliability and performance as an alternative to diesel or biodiesel fuel in low-speed diesel power plants.

Effect of Zr Addition on Selected Properties and Microstructure of Aluminum Alloy AlSi5Cu2Mg

The hypoeutectic aluminum alloy AlSi5Cu2Mg is used for the production of high-strength cylinder head castings. The alloy is unique for its specific low permitted Ti content (0.03 wt% max), which makes it impossible to refine the grain structure of this alloy using standard Al–Ti–B grain refiners. The specific chemical composition is specified by the supplier company. The aim of this paper is to find a suitable alloying element that would improve the selected properties (e.g., mechanical, and physical properties) that are crucial for cylinder head castings. The research focuses on the investigation of the effect of different Zr addition (0.05; 0.10; 0.15 and 0.20 wt% Zr in the form of AlZr20 master alloy) on the properties of AlSi5Cu2Mg in the as-cast state and after heat treatment T7. The obtained results showed that ultimate tensile strength, yield strength, hardness, and physical properties of as-cast samples do not change significantly with increasing Zr content. The experimental alloys showed a more significant increase in ultimate tensile strength, yield strength, hardness, and thermal conductivity after heat treatment T7. Zirconium-rich intermetallic phases were observed in the shape of separate thick needles or as a cluster of two crossed thinner needles.

Production of the cylinder head and crankcase of a small internal combustion engine using metal laser powder bed fusion

This effort investigates the use of metal additive manufacturing, specifically laser powder bed fusion (LPBF) for the automotive and defense industries by demonstrating its feasibility to produce working internal combustion (IC) engine components. Through reverse engineering, model modifications, parameter selection, build layout optimization, and support structure design, the production of a titanium crankcase and aluminum cylinder head for a small IC engine was made possible. Computed tomography (CT) scans were subsequently used to quantify whether defects such as cracks, geometric deviations, and porosity were present or critical. Once viability of the parts was established, machining and other post-possessing were completed to create functional parts. Final X-ray CT and micro-CT results showed all critical features fell within ±0.127 mm of the original equipment manufacturer (OEM) parts. This allowed reassembly of the engine without any issues hindering later successful operation. Furthermore, the LPBF parts had significantly reduced porosity percentages, potentially making them more robust than their cast counterparts.

Numerical study of heat transfer of hydrogen combustion in noble gases atmosphere in compression ignition engine

The high energy content of hydrogen and zero carbon emission from hydrogen combustion is very important for compression ignition engine development. Hydrogen requires a very high auto-ignition temperature, which encourages replacing nitrogen with noble gases with higher specific heat ratio during compression process. In noble gases-hydrogen combustion, higher combustion temperature potentially leading to a higher heat loss. This paper aims to investigate the effect of hydrogen combustion in various noble gases on heat distribution and heat transfer on the cylinder wall. Converge CFD software was used to simulate a Yanmar NF19SK direct injection compression ignition engine. The local heat flux was measured at different locations of cylinder wall and piston head. The heat transfer of hydrogen combustion in various noble gases at different intake temperatures was studied using the numerical approach. As a result, hydrogen combustion in light noble gases such as helium produces faster combustion progress and higher heat temperature. The hydrogen combustion that experienced detonation, which happened in neon at 340 K and argon at 380 K, recorded a very high local heat flux at the cylinder head and piston due to the rapid combustion, which should be avoided in the engine operation. At a higher intake temperature, the rate of heat transfer on the cylinder wall is increased. In conclusion, helium was found as the best working gas for controlling combustion and heat transfer. Overall, the heat transfer data gained in this paper can be used to construct the future engine hydrogen in noble gases.

Optical study of knocking phenomenon in a spark-ignition engine by using high-speed OH* chemiluminescence imaging: A multiple ignition sites approach

Knock in a spark-ignition (SI) engine is a complicated combustion phenomenon that stimulates high-pressure oscillations inside the combustion chamber and restricts engine performance. This study presents a high-speed OH* chemiluminescence imaging technique to investigate the knock mechanism resulting from firing multiple spark plugs. The experiment was performed using a customized liner having three spark plugs installed at equal spacing, and to compare the results with conventional SI conditions, in which one spark plug was mounted at the center of the cylinder head. In addition, multiple pressure transducers were used at various locations to record the frequencies induced by the pressure oscillations inside the cylinder during knocking events. The results showed that firing a single central spark plug generated mild knock with late combustion phasing and lower power output. However, adding more spark plugs could advance the initiation of autoignition and produce higher knock intensity along with lower combustion duration for the same operating conditions. Additionally, a weak OH* chemiluminescence intensity oscillation was monitored before the autoignition of the unburned charge occurred. The crank angle location of peak OH* intensity and peak HRR showed a good linear curve fit with a positive slope. Furthermore, the larger amount of unburned mass fraction produced stronger pressure waves due to multiple autoignition sites, and the unburned mass fraction exhibited a good linear relationship with unburned temperature and end-gas area at the knock onset point. Moreover, the frequency spectrum recorded by the multiple pressure sensors illustrated that in the case of a single central spark plug only circumferential acoustic waves were formed with low power intensity. However, multiple ignition sites promoted both circumferential and radial pressure waves inside the combustion chamber because of multiple autoignitions occurring both near the center and cylinder wall.

The effect of thermal exposure on the microstructure and mechanical properties of cast Al-Si alloy for the cylinder head

Cast Al-Si alloy is widely used in cylinder head structures and long-term service in 200–250 °C elevated temperature environments, which is easy to cause the deterioration of alloy properties. In this study, the thermal stability of the alloy during thermal exposure at 200 °C and 250 °C is investigated through the microstructure characterization and the mechanical properties test. The results show that the thermal exposure leads to the damage evolution of the precipitates in the microstructure. With the coarsening of the precipitates, the dislocation changes from cutting precipitates to bypassing precipitates, resulting in a weakening of the precipitation strengthening effect. The T6 alloy is in the insufficient peak aging state, and the alloy first reaches the peak aging state and then enters the over aging stage during the thermal exposure. Overall, with the increase in thermal exposure time and temperature, the Al matrix hardness, ultimate tensile strength (UTS), and yield strength (YS) decrease gradually and finally tend to be stable. As the thermal exposure progresses, the alloy fracture characteristic transitions from brittle fracture to ductile fracture, and the elongation of the alloy increases. In addition, the coarsening process of the thermal exposure alloy is described based on the Lifshitz-Slyozov-Wagner (LSW) theory, and the modified coarsening kinetic model can be divided into the rapid roughening stage and the stable roughening stage. Further, the damage parameter is defined as the relative change of precipitation strengthening to describe the deterioration degree of the mechanical properties for thermal exposure alloy.

An Analysis of The Material and Design of an Exhaust Manifold for A Single-Cylinder Internal Combustion Engine

This study aims to find the best material for the manifold and improve airflow in the UniMAP Automotive Racing Team (uniART) exhaust manifold. The exhaust manifold is a part of the exhaust system that collects and delivers exhaust gases from the cylinder head to the exhaust outlet. The exhaust manifold’s design is significant to the engine performance. The current design and new designs of the exhaust manifold were modelled using SOLIDWORKS software. Stainless steel, cast iron and mild steel were chosen as materials for manifold and were studied by conducting the Steady-State Thermal analysis. The flow of the air in the manifold is analysed and evaluated in terms of pressure and velocity. The fluid flow and thermal analysis are simulated in Computational Fluid Dynamics analysis software known as ANSYS. Results of thermal analysis prove that Stainless steel is better than other materials since it has a high temperature difference and low heat flux. The results of fluid flow analysis were compared between the current design and new designs of the exhaust manifold. The outcome indicated that validated Design 2 has a higher velocity value at the outlet and lower pressure at inlets which improves the airflow in the exhaust manifold.