Cylinder Bore Research Articles

Oilstone Processing and Its Impact on the Surface Texture of Cylinder Bore

AbstractHoning is one of the abrasive-based machining processes to remove material through the asperity interaction between numerous stochastic grains distributed on oilstone (also called honing stone) and workpiece. Therefore, the oilstone surface topography characterized by grain morphology, size, posture and position distribution, protrusion heights and etc. is of great significance to understand honing mechanism in terms of establishing an accurate kinematic model and further analyzing the oilstone property's impact on honing process and honed surface texture characteristics including groove density, roughness heights, and plateau/valley amplitudes. Conventionally, two typical approaches have been employed to establish the surface topography of abrasive-based cutting tools: experimentally microscopic observation and backward modeling/simulation from the assumed ideal distribution laws such as Gaussian or uniform distribution for stochastic grain characteristics. The first method is usually time-consuming and only measures surface topography within rather small area, whereas the second one is highly dependent on the authenticity of assumed statistical distribution laws. To overcome these weaknesses, the research proposed a functional forward method (FFM) to accurately predict surface topography of oilstone based on simulating its manufacturing processes in succession to avoid distributional assumptions and geometrical simplification. The methodology takes into consideration five important stochastic characteristics of oilstone including grain morphology, size, posture, position distribution, and grain wear during honing process, to guarantee the credibility, authenticity, and generality of the surface topography generated from honing. Based on the oilstone surface topography, the kinematic simulation method (KISM) was applied to analyze the honed surface texture characteristics of cylinder bore with oilstone samples under different stirring times. Therefore, the methodology bridges oilstone manufacturing parameters, oilstone surface topography, and further the honed surface texture to provide a fresh insight into the parameter’s optimization of the oilstone manufacturing process by achieving a better control on the honed surface texture of the cylinder bore.

An Experimental Study to Understand the Effect of Calibration Parameters and Operating Conditions on Piston and Cylinder Bore Temperatures for a Multi-Cylinder DI Diesel Engine through Piston Telemetry

<div class="section abstract"><div class="htmlview paragraph">In a bid to adopt pro-active strategies to reduce pollution, the Indian government decided to leapfrog from current emission norms to the advanced emission regulations like BS VI, CPCB4. The advancement in emission regulation is also accompanied by customer expectation of increased product performance with lower cost. Downsizing of the engines has led base engine components to experience more thermomechanical loads. Lower product cost demand of the market has pushed engineers to understand the system level interactions and identify the levers other than component design changes. Current analytical techniques provide little iteration feasibility to explore all the possible levers. This paper focuses on experimental study to understand the effect of engine operating conditions on piston and bore temperatures. Piston telemetry technique is used in capturing the real time piston temperature data with flexibility to carry out design of experiments. Bore temperatures were measured using thermocouples. Impact of variation in Rail pressure (RP), injection timing (SOI), engine coolant out temperature, delta pressure and temperature across CAC, Compressor inlet temperature (CIT) and turbine outlet pressure (TOP) were studied. Results of main and interaction effects for individual factors are discussed. Engine COT and injection timings identified as major levers showing linear relation. Other parameters were found as a minor contributing factor, even though those are critical in engine performance tuning.</div></div>

Effect of the Gap Size between the Cathode and the Wehnelt Cylinder Bore on the Emittance of the Thermionic Electron Gun

This paper includes simulating an electron gun design to investigate the effect of the distance between the cathode and the Wehnelt cylinder bore on the quality of the ion beam emittance and to obtain the best distance of that geometrical factor. A study of a group of designs was conducted to find this distance. The SIMION8.0 program has been used to calculate the trajectories of the electrons with initial kinetic energy of (0.1 eV) and electron current of (1×10-12 A). The investigation also includes comparisons between the equipotential line trajectories for each design as well as the field distribution and the electron trajectories. The best emittance distance was concluded to be (3 mm).

Dynamic Contact Analysis of Piston Ring in Distorted Cylinder Bore (Second Report)

Dynamic Contact Analysis of Piston Ring in Distorted Cylinder Bore (Second Report)

Enhanced Hybrid Model to Predict the Surface Roughness of Honed Cylinder Bore

Abstract Cylinder bore honing is a finishing process that generates a crosshatch pattern with alternate valleys and plateaus responsible for enhancing lubrication and preventing gas and oil leakage in the engine cylinder bore. The required functional surface in the cylinder bore is generated by a sequential honing process and is characterized by Rk roughness parameters (Rk, Rvk, Rpk, Mr1, Mr2). Predicting the desired surface roughness relies primarily on two techniques: (i) analytical models (AM) and (ii) machine learning (ML) models. Both of these techniques offer certain advantages and limitations. AM's are interpretable as they indicate distinct mapping relation between input variables and honed surface texture. However, AM's are usually based on simplified assumptions to ensure the traceability of multiple variables. Consequently, their prediction accuracy is adversely impacted when these assumptions are not satisfied. However, ML models accurately predict the surface texture but their prediction mechanism is challenging to interpret. Furthermore, the ML models' performance relies heavily on the representativeness of data employed in developing them. Thus, either prediction accuracy or model interpretability suffers when AM and ML models are implemented independently. This study proposes a hybrid model framework to incorporate the benefits of AM and ML simultaneously. In the hybrid model, an artificial neural network (ANN) compensates the AM by correcting its error. This retains the physical understanding built into the model while simultaneously enhancing the prediction accuracy. The proposed approach resulted in a hybrid model that significantly improved the prediction accuracy of the AM and additionally provided superior performance compared to independent ANN.

Friction Minimization through Microstructures on the Cylinder Bore Surface

Friction Minimization through Microstructures on the Cylinder Bore Surface

Numerical and Experimental Analysis of the Potential Fuel Savings and Reduction in CO Emissions by Implementing Cylinder Bore Coating Materials Applied to Diesel Engines

Currently, internal combustion engines contribute to the problem of global warming due to their need to use products derived from fossil resources. To mitigate the above problem, this study proposes the use of coatings on the cylinder bore in order to reduce fuel consumption and polluting emissions. Therefore, in the present study a numerical model is developed in which the tribological behavior, heat fluxes, and leakage of the combustion gases in the chamber are considered to evaluate the influence of the coating. Nickel nanocomposite (NNC) and diamond-like carbon (DLC) coatings are considered in the study. The results demonstrate that the NNC coating produces a 32% reduction in the total friction force of the compression ring. The estimated maximum temperatures for the lubricating oil were 214, 202, and 194 °C for the DLC, steel, and NNC materials. Increasing the temperature in the DLC coating can cause a reduction in the tribological performance of the lubricant. The estimates made show that the implementation of the NNC coating allows a maximum reduction of 5.28 ton of fuel and 39.30 kg of CO emissions, which are based on the global fleet of diesel engines forecast for the year 2025 (corresponding to one hundred and eighty million engines) and a test time of 1800 s. The proposed numerical model allows future analyses to be carried out for other types of materials used as coatings. Additionally, the model can be expanded and adapted to consider other systems that involve friction processes in the engine.

ススによって発生するシリンダボア・ピストンリング摩耗の解析(2) ―ディーゼルエンジンのEGR摩耗に対する表面分析からの解析―

ススによって発生するシリンダボア・ピストンリング摩耗の解析(2) ―ディーゼルエンジンのEGR摩耗に対する表面分析からの解析―

ススによって発生するシリンダボア・ピストンリング摩耗の解析(1):―ディーゼルエンジンのEGR 摩耗に対するピストン摩擦力からの解析―

ススによって発生するシリンダボア・ピストンリング摩耗の解析(1):―ディーゼルエンジンのEGR 摩耗に対するピストン摩擦力からの解析―

Analytically Predicating the Multi-Dimensional Accuracy of the Honed Engine Cylinder Bore

Abstract The dimensional accuracy of engine cylinder bore at multiscale has a tremendous influence on engine performances including friction power loss, vibration, leak tightness between piston and cylinder, and wear resistance. Tremendous researches were devoted to predict the dimensional accuracies of the honed cylinder by means of analytical, experimental, and numerical simulation methods. The dimensional quality of the honed cylinder bore was usually determined by establishing the relationship between honing parameters and dimensional accuracies of the honed cylinder bore. However, most researches predicted dimensional accuracy at macroscale or surface texture at microscale, respectively. Few efforts were devoted to predict the dimensional quality of honed cylinder bore at both macroscale and microscale levels simultaneously. To explore a new understanding of the honing mechanism of the cylinder bore, a multiscale model is proposed to predict the dimensional accuracy and surface texture of cylinder bore generated from the honing process at the macroscale and microscale simultaneously. The model aims to integrate both microscale factors including honing stone abrasives distribution, abrasive wear process, previous cylinder surface topography, and macroscale factors including cylinder geometric features and honing head motion trajectory into a multiscale analytical analysis. A force matching method is adopted in the multiscale predictive model to determine the feed depth in the honing of the cylinder bore. Thus, the proposed multiscale analytical model possesses an excellent capacity to simultaneously predict the roundness and cylindricity of the honed cylinder bore, as well as the surface texture/roughness of the honed cylinder bore in terms of Abbott-Firestone curve. The simulated results also revealed that the material removal process is closely related to the initial shape deviations of the cylinder bore, which cannot be corrected, compensated, or eliminated by the subsequent honing process given the deviations are associated with wavelengths higher than 27 mm under the given honing condition.

A Multiscale Cylinder Bore Honing Pattern Lubrication Model for Improved Engine Friction

A Multiscale Cylinder Bore Honing Pattern Lubrication Model for Improved Engine Friction

Influence of Oxides on the Performance of Cylinder Bore Coatings of Engine Blocks

The performance of thermally sprayed coatings such as for the inner surface of combustion engines depends on the microstructure and phase composition of the coatings after deposition. These can be varied in a targeted manner to reach the desired coating behavior. One approach might be altering the atomization gas in order to influence the oxide content in the coating. A former study of the authors already showed that the oxide content in the coatings can be influenced effectively by simply changing the atomization gas in case of Plasma Transferred Arc Spray technology. In this study, a systematic approach is followed in order to investigate the effect of oxides on the tribological performance and the corrosion behavior. For this purpose, coatings with different oxide contents were manufactured by taking advantage of different atomization gases. The results of this study confirm that coatings with pronounced oxide‐rich phases exhibit lower friction coefficients and less sever outbreaks in comparison to those without distinctive oxide‐rich phase. The presence of oxide‐rich phases does not influence the corrosion behavior of the coatings significantly, although some minor effects are observed along phase boundaries.

Dynamic Contact Analysis of Piston Ring in Distorted Cylinder Bore

Dynamic Contact Analysis of Piston Ring in Distorted Cylinder Bore

A Study on Piston Ring Conformability to Cylinder Bore Influencing on Lubricating Oil Consumption

A Study on Piston Ring Conformability to Cylinder Bore Influencing on Lubricating Oil Consumption

Friction Reduction of Piston Rings by Dimple Micro Texture of Automotive Cylinder Bore

Friction Reduction of Piston Rings by Dimple Micro Texture of Automotive Cylinder Bore

Effect of Different Atomization Gases on the Properties of Cylinder Bore Coatings

Oxidation during coating deposition by means of thermal spraying is a widely investigated and discussed topic. Most of the studies dealing with this subject report negative influences of oxidation on the coating properties, especially with respect to corrosion behavior. On the other hand, positive effects are reported as well, especially with regard to tribological behavior. Within this study, the oxidation phenomena in Plasma Transferred Wire Arc (PTWA) spraying process is investigated in detail. This technology is primarily used to apply coatings on the inner surface of cylinder bores in combustion engines. It is shown that the oxidation can be suppressed effectively by utilizing an alternative atomization gas like nitrogen instead of compressed air without the need of any additional torch modification. Besides the oxidation behavior, further effects depending on the used atomization gas are observed, which influence the properties of the coatings. Significantly higher hardness values are measured for the coatings deposited with nitrogen. This is traced back to different impact and cooling conditions as well as chemical interactions of the in‐flight particles with the ambient atmosphere.

Continuous Lubricant Film Thickness Measurement Between Piston Ring and Cylinder Bore

Measurement of film thickness between piston ring and cylinder bore has been a challenge for decades; laser-induced fluorescence (LIF) method was used by several groups, and promising results are obtained for the investigation of lubricant film transport. In this study, blue light generated by a laser source is transmitted to a beam splitter by means of a fiber optic cable and combined with another fiber optic line, then transmitted to the piston ring and cylinder bore conjunction. The light causes the fluorescence dye present in the lubricant to emit light in a longer wavelength, i.e., green. Reflected light is recollected; blue wavelength components are filtered out using a narrow band pass optical filter, and only components in the florescence wavelength is transmitted to a photomultiplier tube. The photomultiplier produces a voltage proportional to instantaneous lubricant film thickness. Then, the photomultiplier signal is calibrated for lubricant film thickness using a laser textured cylinder bore with known geometries. Additional marks were etched on the liner for calibration. The LIF system is adapted to a piston ring and cylinder bore friction test system simulating engine conditions. Static piston ring and reciprocating liner configuration of the bench test system allow the collection of continuous lubricant film thickness data as a function of crank angle position. The developed system has potential to evaluate new designs, materials, and surface properties in a controlled and repeatable environment.

Predicting Microscale Cross-Hatched Surface Texture in Engine Cylinder Bore

Cross-hatched texture is the essential surface feature in cylinder bore generated from honing process. The interconnected grooves of the surface texture provide storage space and diffusion channels for the lubrication oil. Thus, it is widely used to reduce contact friction, lubrication oil consumption and improve the wear resistance of piston-ring contact pairs in automotive engine. The surface texture was simulated by various analytical methods in literatures. However, the mechanism of generation of surface texture stays a black box and poses a challenge to further control engine quality. This study presents a new kinematic model to simulate the generation of cross-hatched surface texture in the honing process of engine cylinder bore. It formulates the process motions based on honing operations in automotive industry. And a microscale model is established to simulate honing stone surface topography with randomly distributed abrasive particle sizes, postures and distributions obtained by a modified Poisson disk sampling algorithm. The kinematic simulation is performed by moving the honing stone surface topography along the motion trajectory. Abrasive particles interact with cylinder surface and generate texture grooves as honing stones feed. Using this method, honing surface texture is demonstrated with cross-hatched feature at microscale level, and the difference of cross-hatched texture is revealed visibly and quantitively as roughness corresponding to honing stones with different abrasive particle shapes, wear conditions and position distributions in height direction.

Methodology to Improve the Cylindricity of Engine Cylinder Bore by Honing

Cylindricity of engine cylinder bore is identified as one of the crucial factors to exert great influence on engine performance including piston friction and wear, energy consumption, and gas emission. Cylindricity at macroscopic level as well as surface roughness at microscopic level such as peak roughness, core roughness, and valley roughness of engine cylinder bore is typically generated by honing operations. However, the selection of the process parameters of honing is currently based on empirical methods since honing is mechanically complex process. It thus makes a significance to analytically investigate honing operation to effectively improve the cylindricity of engine cylinder bore based on its functional requirements. This research aims to explore the methodology on achieving the desired cylindricity for engine cylinder bore through several approaches including simulating honing motion trajectory, improving honing head structure, coordinating cylinder bore honing with its previous boring operation, and optimizing honing parameters such as honing velocity, stroke speed, and overrunning distance. The research presents a systematical thinking to achieve macrogeometrical features in the honing of engine cylinder bore and a theoretical approach for the successful selection and optimization of honing process parameters.

Optimization of Engine Cylinder Bore Wall Temperature Distribution during Combustion (Part 1)

Optimization of Engine Cylinder Bore Wall Temperature Distribution during Combustion (Part 1)