Lubricating Oil Temperature Research Articles

Simulation and Analysis of the Impact of Cylinder Deactivation on Fuel Saving and Emissions of a Medium-Speed High-Power Diesel Engine

The potential benefit of cylinder deactivation (CDA) on power and emission performances has been numerically investigated on a locomotive 16-cylinder diesel engine. A 1D model combined with a predictive friction model and a 3D combustion model based and validated on experimental data have been developed to simulate engine working processes by deactivating half of the cylinders by cutting off the fuel supply and maintaining/cutting off valve motions. The results demonstrate that CDA with the valves closed decreases the BSFC by 11% at 450 rpm and by 14% at 556 rpm with a load of 1000 N∙m, due to increased indicated efficiency and reduced mechanical losses. After deactivating cylinders, frictional losses of piston rings increase in the active cylinders because of the raised gas pressure and the lubricating oil temperature decrease. Friction losses of the main bearings and big-end connecting rod bearings decrease due to the overall load drop. In comparison with the normal operation, CDA with the valves closed decreases the BSCO emission by 75.26% and the BSsoot emission by 62.9%. As the EGR rate is 30%, CDA with the valves closed effectively reduces the BSNOx emission to 4.2 g/(kW·h) at the cost of a 0.8% increase in the BSFC and without the rise in the BSCO emission.

Modeling and prediction for diesel performance based on deep neural network combined with virtual sample

The performance models are the critical step for condition monitoring and fault diagnosis of diesel engines, and are an important bridge to describe the link between input parameters and targets. Large-scale experimental methods with higher economic costs are often adopted to construct accurate performance models. To ensure the accuracy of the model and reduce the cost of the test, a novel method for modeling the performances of marine diesel engine is proposed based on deep neural network method coupled with virtual sample generation technology. Firstly, according to the practical experience, the four parameters including speed, power, lubricating oil temperature and pressure are selected as the input factors for establishing the performance models. Besides, brake specific fuel consumption, vibration and noise are adopted to assess the status of marine diesel engine. Secondly, small sample experiments for diesel engine are performed under multiple working conditions. Moreover, the experimental sample data are diffused for obtaining valid extended data based on virtual sample generation technology. Then, the performance models are established using the deep neural network method, in which the diffusion data set is adopted to reduce the cost of testing. Finally, the accuracy of the developed model is verified through experiment, and the parametric effects on performances are discussed. The results indicate that the overall prediction accuracy is more than 93%. Moreover, power is the key factor affecting brake specific fuel consumption with a weighting of 30% of the four input factors. While speed is the key factor affecting vibration and noise with a weighting of 30% and 30.5%, respectively.

Design and Evaluation the Anti-Wear Property of Inorganic Fullerene Tungsten Disulfide as Additive in PAO6 Oil

Inorganic fullerene-like tungsten disulfide particles have been proved to have good anti-friction and anti-wear properties as lubricating materials. As far as we know, however, when it is used as a lubricant additive, its behavior and action mechanism in the friction process are rarely studied. Herein, IF–WS2 particles were synthesized by a Chemical Vapor Deposition (CVD) method. The effect of IF–WS2 particle concentrations in the PAO6 oil on the tribological behaviors was investigated with a four-ball wear machine at both 75 and 100 °C. Additionally, the analyzed morphology and composition of nanomaterials and worn surfaces were analyzed by Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The friction behavior in actual working conditions was studied by a wear testing machine. The experimental results show that compared with the original PAO6 oil, at a dispersion of 0.25 wt% in PAO6 oil, the IF–WS2 particles showed the best performance in terms of coefficient of friction, wear scar diameter and wear mass, which significantly reduced by 27%, 43% and 87%, respectively. At the same time, in the process of friction, it was found that IF–WS2 particles accumulated in the depressions to fill the scratches, and adsorption films and chemical films, including FeS2, WS2 and WO3, were formed on the worn surfaces to avoid the direct contact among the friction pairs more effectively, resulting in the improved anti-wear performances. Additionally, the addition of IF–WS2 particles effectively delayed the rise of lubricating oil temperature. In addition, dispersant span 80 can effectively improve the dispersion and stability of IF–WS2 in PAO6. This work provides us for understanding the effective lubrication mechanism of IF–WS2 particles in more detail and having a new acknowledge of the comprehensive performance of IF–WS2/PAO6 oil.

A Hybrid Intelligent Model for the Condition Monitoring and Diagnostics of Wind Turbines Gearbox

Wind turbines (WTs) are often operated in harsh and remote environments, thus making them more prone to faults and costly repairs. Additionally, the recent surge in wind farm installations have resulted in a dramatic increase in wind turbine data. Intelligent condition monitoring and fault warning systems are crucial to improving the efficiency and operation of wind farms and reducing maintenance costs. Gearbox is the major component that leads to turbine downtime. Its failures are mainly caused by the gearbox bearings. Devising condition monitoring approaches for the gearbox bearings is an effective predictive maintenance measure that can reduce downtime and cut maintenance cost. In this paper, we propose a hybrid intelligent condition monitoring and fault warning system for wind turbine's gearbox. The proposed framework encompasses the following: a) clustering filter- (based on power, rotor speed, blade pitch angle, and wind speed signals)-using the automatic clustering model and ant bee colony optimization algorithm (ABC), b) prediction of gearbox bearing temperature and lubrication oil temperature signals- using variational mode decomposition (VMD), group method of data handling (GMDH) network, and multi-verse optimization (MVO) algorithm, and c) anomaly detection based on the Mahalanobis distances and wavelet transform denoising approach. The proposed condition monitoring system was evaluated using 10 min average SCADA datasets of two 2 MW on-shore wind turbines located in the south of Sweden. The results showed that this strategy can diagnose potential anomalies prior to failure and inhibit reporting alarms in healthy operations.

CFD-Based Investigation of Lubrication and Temperature Characteristics of an Intermediate Gearbox with Splash Lubrication

In this study, we propose a computational fluid dynamics (CFD)-based method to study the lubrication and temperature characteristics of an intermediate gearbox with splash lubrication. A volume of fluid (VOF) multiphase model was used to track the interface between oil and air. A multiple reference frame (MRF) model was adopted to accurately simulate the movement characteristics of the gears, bearings, and the surrounding flow field. The thermal-fluid coupling computational model of an intermediate gearbox with splash lubrication was then established. Combined with experimental results, we verified that the lubricating oil temperature was below the limit requirement (<110 °C). The numerical results revealed that large amounts of lubricating oil were splashed onto the tooth surfaces near the gear meshing area. A large convective heat transfer coefficient corresponds to a low gear tooth surface temperature. The tooth surface temperature of the driving gear is higher than that of the driven gear. The distribution law of oil volume fraction of the bearing roller was jointly affected by the roller rotation direction and gravity. The convective heat transfer coefficient of the roller wall was largely related to the lubrication environment of the roller, including the oil distribution inside the bearing cavity and the flow rate.

Wear resistance mechanism of engine piston skirt coating under cold start condition

At the beginning of cold start, the lubricating oil temperature is low, the kinematic viscosity is high, the splash lubrication effect is poor, and the good lubricating oil film cannot be formed, therefore, the friction and wear between piston and cylinder is serious. In this paper, the wear mechanism of aluminum alloy piston skirt coating was studied in the cold start stage with severe wear degree: the dynamic simulation and cold start test analysis were carried out for the skirt with or without coating, and the wear morphology, knife pattern structure and friction force were compared, so as to determine the friction reduction energy efficiency of the coating in the cold start stage.

Combustion Analysis of a Diesel Engine during Warm up at Different Coolant and Lubricating Oil Temperatures

A comprehensive analysis of combustion behaviour during cold, intermediately cold, warm and hot start stages of a diesel engine are presented. Experiments were conducted at 1500 rpm and 2000 rpm, and the discretisation of engine warm up into stages was facilitated by designing a custom drive cycle. Advanced injection timing, observed during the cold start period, led to longer ignition delay, shorter combustion duration, higher peak pressure and a higher peak apparent heat release rate (AHRR). The peak pressure was ~30% and 20% and the AHRR was ~2 to 5% and ±1% higher at 1500 rpm and 2000 rpm, respectively, during cold start, compared to the intermediate cold start. A retarded injection strategy during the intermediate cold start phase led to shorter ignition delay, longer combustion duration, lower peak pressure and lower peak AHRR. At 2000 rpm, an exceptional combustion behaviour led to a ~27% reduction in the AHRR at 25% load. Longer ignition delays and shorter combustion durations at 25% load were observed during the intermediately cold, warm and hot start segments. The mass fraction burned (MFB) was calculated using a single zone combustion model to analyse combustion parameters such as crank angle (CA) at 50% MFB, AHRR@CA50 and CA duration for 10–90% MFB.

Research and application of digital virtual maintenance system for steam turbine

After a 430MW machine unit was started with C repair finished, the shafting vibration of it increase rapidly at the phase of on-load. Using the on-line vibration monitoring and fault diagnosis system (TDM system) matched with the unit to check the vibration historical data, and according to the vibration characteristics, oil film vortex fault is diagnosed. In view of this, the vacuum test was carried out on the lubricating oil temperature of the main transformer engine and the condenser of the unit. The results show that the low frequency variable oil temperature and the condenser can be restrained in a large certain load range. The distribution measures of bearing load are adjusted by unit’s adjustment to increase the load of No.3 bearing, so as to eliminate the unit’s low-frequency vibration fault and ensure the normal operation of the unit.

The effect of different coolants on emissions and fuel consumption of a diesel engine

A diesel engine performance test system is set up based on the AVL framework, and an experimental investigation is conducted to evaluate the effects of three coolants on the diesel engine coolant outlet temperature, lubricating oil temperature, exhaust emissions and fuel consumption under real engine conditions. The results show that when the coolant circulating temperature is 80 °C, the exhaust temperature of the diesel engine using C-PG (anhydrous propylene glycol) coolant is the lowest, and the lubricating oil temperature is increased by 5 °C. Thus, when the coolant circulating temperature is 95 °C, the C-PG coolant is used. The outlet temperature and the lubricating oil temperature are similar to those of the other two coolants. The nitrogen oxides (NOx) emission of the diesel engine using C-PG coolant is slightly higher than that with the other two coolants, while the soot, carbon monoxide (CO) and hydrocarbon (HC) emissions are reduced. Finally, when the coolant circulating temperature is 95 °C, the fuel consumption using the C-PG coolant and L2 lubricating oil is reduced by 3.8%, compared with the C-EG (mixture of water and ethylene glycol) coolant and L1 lubricating oil.

Effect of lubricating oil temperature on friction coefficient, oil film thickness, and polarizability of transformed layer in friction of ta-CNx film in base oil

Effect of lubricating oil temperature on friction coefficient, oil film thickness, and polarizability of transformed layer in friction of ta-CNx film in base oil

Preliminary results on nano-diamond and nano-graphite testing as additive for an engine lubrication oil

An important amount of the fuel energy burned in an internal combustion engine is used to overcome the friction losses inside the engine. Developing advanced lubricants is one of the ways to improve the fuel efficiency and reducing the pollution caused by internal combustion engines. This paper presents tests done with 1% v/v nano-diamond and nano-graphite additives in engine oils, with bench tests on an air-cooled spark ignition engine (Honda GX 160) with a displacement of 118 cubic centimeters. Using the raw lubrication oil laboratory, tests were done to determine the viscosity, density and viscosity index using an Anton Paar SVM 3000 viscometer in comparison to the oil with nano-diamond and nano-graphite additives. The tests also revealed an average reduction in fuel consumption of 21% for the single cylinder engine in case of the oil with additives, for the entire speed range of the engine, showing a decrease of the fuel efficiency as the speed increases. The temperature of the exhaust manifold, outer side of the cylinder and the temperature of the oil pan were measured. By adding nano-diamond and nano-graphite additives to the lubricant oil, tests have revealed a reduction of the temperature of the exhaust manifold (with 11%), temperature on the outer side of the cylinder was reduced with 21% showing a clear friction reduction within the cylinder and piston-rings assembly. The temperature of the oil pan was reduced with 20%, showing a general reduction of the lubricating oil temperature which means a substantial reduction of the friction losses.

Monitoring of misalignment in low speed geared shafts with acoustic emission sensors

The most common condition monitoring method applied to rotating machines is vibration measurement, although recently it has been proposed that acoustic emission (AE) offers additional advantages in early fault detection and low speed rotation systems. Capturing the AE signals is conditioned by the severe attenuation with distance and the presence of material discontinuities between source and sensor, therefore measurement device placement is more important than in traditional accelerometry. In this study AE signals are measured in gearboxes at misalignment conditions for the revision of signal characteristics from the generated signal due to the interaction of shafts, bearings and gears. For this purpose, several tests are performed using combinations of speed and varying load, considering the effect of lubricating oil temperature. Fixed measurements are taken over the bench supports, and on-board, where the sensors are rotating with the shafts. In parallel to acoustic emission a vibration analysis is done in order to contrast and analyze differences between both technologies at different operation states. Acquired data is processed to obtain statistical parameters from measurements in order to verify the values and tendencies due to transient phenomena related to changes in speed and load. AE provides better results than vibration employing the same time domain condition indicators. On the contrary, vibration recognizes clearly the fault through frequency analysis.

The Effect of Ultrasonic Treatment of a Lubricating Oil on the Operation of a Tribological Assembly and the Assessment of the Residual Effects in the Oil

This paper presents the results of a study of the operation of a “roller—pad” friction pair under the influence of ultrasonic vibrations with a frequency of 8–17 kHz on lubricating oil. Further, the surface tension coefficient and the lubricating oil temperature during its processing in the frequency range of 8–43 kHz is evaluated. It has been established that both ultrasonic treatment of lubricating oil and the increase in the frequency of the treatment significantly improve the operating conditions of the friction pair, reducing the linear wear of samples, the rates of the wear of moving and fixed samples of friction pairs and the wear factor number. It has been established that the surface tension coefficient of synthetic motor oil, decreasing to the minimum value during the first 120 h of ultrasonic treatment, is maintained at this level for more than 72 h.

Influence of pitch and exploitation on the frictional behaviour of the silent chains

The silent chain transmissions are widely used in automotive industry as part of the distribution transmission for the combustion engines. The investigation of friction loses in chains is important in order to find out the influence of their constructive and exploitation parameters. The paper presents the results of the tests performed on a test rig used in the case of transmissions with parallel axes. The main contribution of the paper is represented by determining the influence of speed, tensioning force, temperature and pitch on the friction loses of silent chains. Two types of silent chains are tested: LD6 with the pitch equal with 6.35 mm and LD8 with the pitch equal with 8 mm. The tests have been achieved with the following test parameters: the driver sprocket rotations with the values of 500, 1000, 1800 and 5000 r/min; the tensioning force with the values of 0.5, 1, 2 and 3 kN; the lubrication oil temperature equal with 40°C, 90°C and 115°C. Conclusions are drawn regarding the influence of the chains’ pitch and of the exploitation parameters on the frictional torque. The presence of boundary or mixed friction in the joints of the chain explains the frictional behaviour of the chain.

Numerical and Experimental Investigation of the Sealing Effect of a Specific Labyrinth Seal Structure

A numerical simulation and experimental study were performed to investigate the sealing effect of the labyrinth seal used in a wheel-side reducer. A three-dimensional computational fluid dynamics model was established based on the labyrinth structure. The effects of the temperature and viscosity of lubricant, rotor speed, pressure ratio, clearance, and cavity size of the sealing structure on the sealing were analyzed, and the leakage amount under the corresponding values of different factors was also analyzed. The results indicated that increase in the lubricating oil temperature, viscosity, pressure ratio, and seal clearance lead to decrease in the sealing effect and increases in the leakage. And the effect of rotational speed on the seal is low. To verify numerical simulation, the results of numerical analysis, a test bench was set up to simulate the work of the reducer, and the sealing effect of the sealing structure was examined. The simulation result was compared with the actual results. Both the numerical simulation and experiment indicate that the labyrinth seal achieves the desired sealing effect.

Impact of the Oil Temperature on the Frictional Behavior of Laser-Structured Surfaces

This study investigates how the beneficial effects of laser-manufactured surface microstructures on friction vary with varying oil temperature. Laser surface texturing (LST) is a favorable method to optimize friction and wear, which have always been considerable obstacles against the performance improvement of combustion engines. The aim of this study is to detect correlations between the dimensional parameters of the laser-textured surfaces and tribological performance at varying temperatures. Although the experiments are on a fundamental level, the obvious application of combustion engines has been selected to align the material, processing, and test parameters. A wide range of micro indentations—henceforth called “dimples”—were fabricated onto honed flat aluminum samples by means of ultrashort pulse laser texturing and the frictional behavior at different lubricating oil temperatures (30 and 90 °C) was analyzed.

선박 윤활유 온도 변화에 따른 트로코이드 기어 펌프 이송성능에 관한 연구 -군산대학교 실습선 해림호를 중심으로-

선박 윤활유 온도 변화에 따른 트로코이드 기어 펌프 이송성능에 관한 연구 -군산대학교 실습선 해림호를 중심으로-

Lubricant thermo-viscosity effects on turbocharger performance at low engine load

This work presents the performance and efficiency of a needle bearing type turbocharger under low load condition as affected by lubrication oil temperature and viscosity. The turbocharger on a test bench was propelled by known component exhaust gases with controllable mass flow and temperature at the turbine side. Two API SN multi-grade lubrication oils 0W-20 and 10W-40 were tested. The lubricant flow rates were kept constant by external supply at different inlet temperatures. The turbocharger efficiencies were determined by the measured inlet and outlet temperatures, pressures and flow rates for both turbine and compressor sides as well as the shaft rotational speeds. The experimental results were revealed that the higher inlet temperatures related to the thinner lubricant resulted in higher turbocharger efficiency. It suggests that the lubricant thermal manipulation is required for turbocharger under low load condition to operate within the design performance window.

A study of nonlinear coupling dynamic characteristics of the cold rolling mill system under different rolling parameters

The dynamic characteristics of the mill and the drive system are mutually coupled and affected closed-loop system. However, most research has considered only the vibration of the drive system or the vibration of the mill to determine the cause of the accident in the equipment condition monitoring and fault diagnosis process. Condition monitoring and fault diagnosis based on this type of approach can lead to misdiagnosis or missed diagnosis in determining faults in actual systems. So, in this study, a dynamic model of the coupling between a mill and its drive system was developed to study the interaction of the mill and the drive system with the goal of increasing the accuracy of diagnostic methods and to improve the quality of the rolled material. A nonlinear coupling dynamic model was formulated to represent the relation between the gearbox vibration amplitude and various time-varying parameters to study the effects of various parameters on the drive system vibration characteristic under unsteady lubrication. Simulations results showed that increasing the strip speed, the input strip thickness, or the output strip thickness or decreasing the lubricating oil temperature or the roller radius caused the vibration amplitude of the drive system to increase. The vibration frequency caused by variations in the strip inlet or outlet thickness can be transmitted to the drive system, and gear meshing frequency of the gearbox can be transmitted to the mill. Test data from an actual cold rolling mill verified the accuracy of the model. The model was shown to be capable of simulating the mutually coupled and affected mechanism between a mill and its drive system.

Test bench measurement of friction loss in combustion engine

The results of modeling and bench testing friction losses in the main engine kinematic nodes for different lubricating oil temperature values was presented in the article. The study was performed to evaluate the effect of lubricating oil temperature on the engine friction losses. In addition to friction losses in the crankshaft bearings and the piston rings in a cylinder-piston group the friction loss due to charge exchange in the cylinder, drive of timing system and the oil pump were measured. The obtained results show the course of the friction loss in the combustion engine. The research shows that the thermal state of the engine lubricating oil has effect on the amount of friction losses. Formulated conclusions allow to assess the impact of the oil temperature on the friction losses in the main friction nodes in combustion engine.