The Effects of Ultra-Low Viscosity Engine Oil on Mechanical Efficiency and Fuel Economy

The development of a sustainable powertrain requires improved thermal efficiency. Reducing frictional power losses through the use of ultra-low viscosity oil is one of the most effective and economical ways. To assess the potential for efficiency enhancement in a new generation of future engines using low-viscosity oils, a technical analysis was conducted based on numerical simulation and theoretical analysis. This study proposes a numerical method coupling the whole multi-dynamics model and lubrication model under mixed lubrication regimes. Then, load distribution was calculated numerically and verified experimentally. Finally, this paper compares the bearing load and frictional energy loss of the main bearings when using The Society of Automotive Engineers (SAE) 15W40 and SAE 0W20 oil. The results indicate that the application of ultralow-viscosity lubricant can reduce the hydraulic friction loss up to 24%, but the asperity friction loss would increase due to the reduction in load capacity. As a result, the design of a new generation of high efficiency internal combustion engines requires careful calculation and design to balance the trade-off relations between hydraulic friction and asperity friction.

Study of changes in the coefficient of hydraulic friction of materials of pressure pipes at different temperatures

Снижение затрат электроэнергии на механическую транспортировку воды по напорным трубопроводам за счет уменьшения гидравлического сопротивления внутренних стенок труб носит актуальный характер. Это обстоятельство предопределяет необходимость проведения соответствующих гидравлических испытаний альтернативных материалов, которые могут быть использованы при проектировании и строительстве трубопроводных систем. Целью исследований является выявление характера изменения величины гидравлического трения в зависимости от температурных условий транспортируемой воды и окружающей среды в определенных диапазонах с последующей возможностью управления процессом транспортировки при минимуме затрат на электроэнергию. Достижение поставленных целей осуществляется путем опытного и расчетно-аналитического подходов к определению динамики изменения гидравлических показателей трубопроводов из различных материалов. Представлен комплексный анализ экспериментальных и расчетных данных, полученных с помощью запатентованных автоматизированных комплексов, по определению коэффициентов гидравлического трения для полиэтиленовой трубы и трубы из непластифицированного поливинилхлорида и динамики изменения этих коэффициентов в зависимости от температуры транспортируемых вод и температурных условий прокладки трубопроводов. Reducing the cost of electricity for the mechanical transportation of water through pressure pipelines by reducing the hydraulic resistance of the inner walls of the pipes is of current importance. This circumstance predetermines the need for appropriate hydraulic testing of alternative materials that can be used in the design and construction of pipeline systems. The aim of the study is to identify the nature of the change in the value of hydraulic friction depending on the temperature conditions of the transported water and the environment in certain ranges, with the subsequent possible control of the transportation process with a minimum of energy costs. The set goals are achieved by experimental computational and analytical approaches to determining the dynamics of changes in the hydraulic parameters of pipelines made of various materials. A comprehensive analysis of the experimental and calculated data obtained using patented automated systems for determining the coefficients of hydraulic friction for a polyethylene pipe and a pipe made of unplasticized polyvinylchloride, and the dynamics of changes in these coefficients depending on the temperature of the transported water and the temperature conditions of pipeline laying is presented.

Influence of the temperature factor on the hydraulic resistance of pressure pipes

The assessment of the temperature factor influence on the pressure pipeline hydraulic operation mode is very relevant, since it is considered primarily as an opportunity to reduce the cost of mechanical water transportation. Smaller pressure pipe hydraulic resistances save the electrical energy consumption, and the temperature factor has an additional positive effect on the energy saving process. The purpose of the research is to identify the nature of changes in the hydraulic friction value in relation to the temperature conditions of the transferred water temperature and environmental conditions in the designed ranges, with the subsequent possible control of the transportation process with minimum electrical energy consumption. The method of achieving these goals is an experimental and analytical approach aimed at determining the dynamics of changes in the hydraulic parameters of pipelines made of various materials. The tasks of experimental bench studies include the development of a method for calculating the values of hydraulic friction coefficients for pressure pipelines. The results of hydraulic experiments and comprehensive analysis of the experimental and calculated data for determining the hydraulic friction coefficients for polyethylene pipe are presented. The calculated values of the hydraulic friction coefficient were compared with the experimental ones, which enabled identification of their sufficiently high convergence. The conclusions show a positive effect of reducing hydraulic resistances depending on the increase in the temperature of the transported water.

The hydraulic resistance paradox in rapid narrow pipe waterflow

In this work we present experimental results of cross-sectional speed of water flow in narrow cylindrical metal tubes at high pressure gradients up to 1.1 GPa$$\cdot$$ · m−1. The measurement draws attention to the paradoxical behaviour of flowing water in internal diameters less than 250 $$\upmu$$ μ m. At constant pressure gradient, its cross-section speed decreases with decreasing diameter in accordance with the classical hydrodynamic prediction for turbulent flow in rough cylindrical tube. However for very low diameters below 250 $$\upmu$$ μ m, the cross-section speed rises again and reaches almost the maximum theoretical value of the outflow speed for the appropriate pressure without energy loss caused by contraction or hydraulic friction. Our contribution describes mainly experimental character of the new phenomenon and its motivation is to promptly provide the material for further study to the professional public.

Stabilization of hydraulic characteristics for non-pressure pipelines

The article presents the aspects concerning the preservation of the transporting capacity of the waste water flow in the gravity pipeline during its trenchless renovation by polymer pipes. It is shown that the priority measure to preserve the required degree of self-cleaning of the restored pipeline section, as well as these ones adjacent to it, are the values of the water flow rate and filling in the pipe, which allows to provide the necessary transportation capacity of the entire pipeline system. A formula for determining the length of the rate destabilization zone is proposed and the calculation results using an automated program are given. The program algorithm includes the functions to determine the hydraulic friction coefficients of the pipeline material depending on various parameters, as well as the diameters and lengths of all sections. The essence of the calculations using an automated complex is described and the comparison of the calculation results under different conditions is made. There are given practical recommendations for the potential achievement of the hydraulic balance in the pipeline system and the creation of conditions under which the destabilization zone on the site after the repair becomes minimal.

Flatness-based adaptive nonlinear control for torque tracking of electro-hydraulic friction load simulator with uncertainties

Electro-hydraulic friction load simulator is able to simulate load for detecting and estimating the actuator system, which requires an ability to track accurately a given signal with high frequency. In this article, a flatness-based adaptive nonlinear controller is proposed for electro-hydraulic friction load simulator with parameter uncertainties to improve torque-tracking performance. The proposed control consists of state feedback, desired input feedforward and adaptive law to yield a stable closed-loop control system. State feedback is designed to stabilize the electro-hydraulic friction load simulator and achieve robustness against disturbances. Desired input feedforward is designed based on flatness property. And, it can enhance bandwidth by model compensation. Furthermore, in order to solve the problem of parameter uncertainty, adaptive law is adopted in this controller. The proposed controller theoretically guarantees asymptotic tracking performance in the absence of parameter uncertainties. High-accuracy tracking performance of the proposed control strategy is verified by experiments.

Reduction of Hydraulic Friction in Confined Flows by Laser Texturing: Experiments and Theoretical Validation

Hydraulic friction reduction in a microchannel due to superhydrophobic texturing of its walls was studied theoretically and experimentally. A modified Poiseuille equation formulated from an earlier-established semi-analytical approach to model texturing of slip lengths and the “gas cushion model” was used to predict the hydraulic conductance of a microchannel. An experimental setup with a microfluidic flow cell consisting of syringe pump, pressure manometer and tubing measured the pressure drop at different flow rates through a microchannel. The top and bottom walls of the microchannel was textured with micro-pits using nanosecond pulsed laser on the titanium alloy Ti6Al4V. A very high contact angle was observed on the textured surfaces suggesting entrapped gas bubbles. Liquid slippage leading to reduced hydraulic friction is attributable to the bubbles. The pressure-flow rate characteristics of the microchannels confirm friction reduction and also demonstrate a reasonable agreement with the theoretical predictions from the developed fluid dynamic model.