Till Örebro universitet

Pressure-relief valves have an important role in life protection and system integrity. Valve system has several features and can be modelled as a mass-spring valve system. The current paper attempts to experimentally investigated unstable poppet force equivalent body valve behavior. Unstable fluid force may reproduce the valve body dynamics, resulting in unexpected flow movement fluctuation during opening as well as rising lift adjustment. Such disturbance may create inconsistent poppet valve response during the rapid opening. A lengthy pressure-quarter standing wave conduit links multiple relief valves to the reservoir. The present study proposed two systems for monitor pressure and spring tension to predict the relief valve pressure instability, attempt to deaden it, and avoid popping occurrence. The former system is internal groove in the nozzle worked as a damper, while the latter is compressed heavy oil in the disc holder.

A combined material gear and a method of assembling therefor includes a toothed ring gear having evenly spaced outer gear teeth on an outer circumference and made of a metallic material. An inner ring of the toothed ring gear is configured with evenly spaced inner gear teeth alternating with inner gear grooves. A radially extending rib is centrally located within the inner ring between each inner gear tooth. First and second spline gears, made of one of a thermoplastic material and a powder metal material, have an outer circumference with evenly spaced outer spline teeth alternating with outer spline grooves. The outer spline teeth fit in the inner gear grooves of the toothed ring gear and abut the radially extending rib, with each spline gear being on opposite side. This configuration provides improved damping, self-alignment, and a balance of strength and weight.    Front-page drawing from US12359712B1  

Electric vehicles (EVs) and autonomous vehicles (AVs) are subject to increasing demands for sustainable transportation. In the current paper, a model design is developed that can fit both EV and AV applications. A comparative analysis is studied for power consumption between EVs and AVs, focusing on how the integration of autonomous systems influences energy efficiency. While both EVs and AVs contribute to sustainable transportation, the power demands of AVs are heightened due to the additional computational and sensor systems required for real-time decision-making and navigation. The study evaluates power consumption across several factors, including propulsion, sensor and onboard computation, and HVAC systems, under similar driving conditions. Results indicate that even when Avs and EVs have the same weight, AVs consume more power due to their advanced sensor suites and computational systems, leading to noticeable differences in power consumption across both urban and highway driving scenarios. The findings highlight the impact of automation on vehicle efficiency and provide insights into future design considerations for energy-efficient autonomous transportation. This paper aims to bridge existing gaps in the literature by offering a direct comparison of power usage between EVs and AVs, ultimately contributing to the development of more sustainable vehicle technologies.

There is an increasing need for step-on energy harvesting systems that can transform human foot pressure into electrical power to energize low-power devices, for example, lights or small fans. In the current work, a harvesting system that converts kinetic energy produced during stepping into electrical energy through a pendulum-to-rotary power conversion mechanism is presented. In order to achieve effective energy transmission, the system is designed using a pendulum-pulley architecture that is adjusted for foot pressure dynamics. The mechanism produces energy output while guaranteeing user comfort and versatility in a range of applications by meticulously regulating the pendulum's length, mass, and pulley ratios. Power and motion calculations are presented and the developed design is discussed in different parameter cases. The results show the effectiveness of this application in power production. With possible uses in both public and private areas that might profit from self-sufficient, motion-activated ventilation systems, this solution exemplifies a realistic, environmentally friendly method of energy harvesting.

Finding an effective, clean and sustainable power source, which is independent on traditional power sources, is becoming more necessary. The current work is under an ongoing project for Energy harvesting from human body motion, which aims to create an applicable physical system that uses a pendulum-to-rotary power conversion system to transform the kinetic energy of human body motion into electrical energy. The need for efficient, light and wearable power source mechanism is needed in different applications, such as mobile device chargers, smartwatches, fitness trackers and portable personal fans. In the current work a wearable device system is designed to improve energy production and make the device comfortable and user-friendly. Motion and power calculations are presented and the developed design is discussed in different studied cases. The generated power shows the effectiveness of this application. The studied device can be widely used in applications where energy is harvested and stored utilizing contemporary energy storage devices, allowing low-power gadgets to run continuously without needing to be charged. The initiative sets itself apart by offering an application-focused strategy that illustrates a practical way to incorporate energy harvesting into daily tasks.

Purpose: Studying the system's natural frequencies is crucial to prevent resonance phenomena that can harm both the system and the people around it. Resonance can occur when the system is excited by an applied forced frequency that coincides with the system's natural frequency. Therefore, it is important to avoid running the system at a frequency equal to or close to one of its natural frequencies. However, it is not always possible to have control of the excitation or the applied frequency to avoid matching the system's natural frequencies.

Methods: The current article examines two developed techniques, namely the electromagnet-based technique and the water-based technique, for altering the system's natural frequency through mass variation. The electromagnet-based technique is also used with the Tuned Mass Damper TMD, which can be applied for the same purpose.

Results: Dynamic modelling is presented, and the amplitude ratios are calculated. Experimental tests are conducted to prove the techniques' applicability. The presented methods demonstrate the potential for avoiding resonance through natural frequency variation, thereby enhancing the safety and reliability of the operating system.

Conclusion: The presented methods show the possibility of avoiding resonance via natural frequency. The applied techniques are compared, and their applications are discussed in terms of response and solution applicability.

A multi-speed transmission for a vehicle has an extension in an axial direction and includes first and second input shafts, first and second output shafts, and first and second intermediate shafts. The transmission includes an annulus internally toothed first ring gear drivingly connected to the second input shaft and an annulus internally toothed second ring gear releasably connected to the first ring gear. The first intermediate shaft includes first and second gear wheels respectively in engagement with the first ring gear and the second ring gear. The second intermediate shaft includes a third gear wheel in engagement with the first ring gear and a fourth gear wheel in engagement with the second ring gear. The first output shaft includes a fifth gear wheel in engagement with second gear wheel, and the second output shaft includes a sixth gear wheel in engagement with the fourth gear wheel.

Avoiding resonance, which can occur when the system is excited by a frequency equal to or close to one of the system’s natural frequencies, is crucial to ensure a safe operational system. It is essential to ensure that the system runs at a frequency away from the natural frequencies, which are the resonance frequencies. Sometimes, it is not feasible to vary the operational frequency to avoid the resonance frequencies. Therefore, the current research presents an experimental technique, namely the water-based technique for mass variation, to introduce a method of shifting the natural frequency. A beam system, with a force exciter, accelerometer and two water tanks, is studied as a case study. The mass variation can be used to shift the natural frequency away from the excitation frequency. Different water flow rate cases are examined experimentally, and the obtained response signals are studied. The application of the presented technique is discussed. The results of the tested cases show the feasibility of changing the mass to avoid resonance. The natural frequency shifting is obtained to save the system from high resonance vibration levels that may cause damage to the system.

Avoiding resonance is crucial in design to save the system from high vibration levels that can be induced at the resonance frequency. When the excitation frequency equals one of the systems' natural frequencies resonance can happen. Therefore, to avoid resonance it is essential to evaluate the systems' natural frequencies and avoid exciting the system by one of them. However, controlling the excitation frequency is sometimes not feasible. So, in this case, shifting the natural frequency is useful to save the structure. The current article discusses the effect of adding or removing mass on the system's natural frequency of a water tower. Changing mass can be implemented by pumping or draining an amount of water. Modelling the controlled tower system is presented and studied. A Single Degree of Freedom SDOF model is used for examining the relation between the amount of pumped or drained water and the natural frequency shift. Different cases of frequency shift are studied. Dynamic response signals and Frequency Response Functions are obtained to demonstrate the impact on the system's natural frequency. The control system layout is presented. The article concludes with results that can be useful practically in saving the tower structure. The natural frequency can be shifted significantly by controlling the amount of water.

With the increasing demand for sustainable and auxiliary energy solutions, innovative energy harvesting techniques are gaining more traction. This study explores the application of a pendulum-based energy harvesting mechanism in vehicles, utilizing the natural oscillations induced by vehicle movement to generate electrical power. In the current article, a pendulum-based mechanism is developed for energy generation in vehicle applications. The article presents theoretical analyses of motion dynamics, energy conversion efficiency, and system integration feasibility. The developed mechanism is designed for vehicle applications to be excited by car motion. The calculation results indicate the applicability and how effective the developed mechanism is. The proposed design should be fabricated in a small size and lightweight to be installed in the back trunk of the car or other parts where it can be fixed, preferably close to the suspension system, to have higher excitation.