Engine Compartment Research Articles

The investigation of support effect from hard substrate to soft coating of PI/EP-PTFE under different coating thicknesses and frictional contacts

Engine bearings on ships can experience rapid failure under extreme conditions, such as when seawater infiltrates the engine compartment due to collisions with reefs or missile attacks. To enhance the self-lubrication and wear resistance of these bearings, a composite coating consisting of ZrO2-PI/EP-PTFE has been designed. This coating was applied using liquid spraying technology onto the surfaces of A370 aluminum alloy, CuPb22Sn2.5 copper alloy, and 15# carbon steel. Three different coating thicknesses—20 μm, 30 μm, and 40 μm—were applied to each substrate. The tribological properties of these coatings on the three substrates were investigated under both dry sliding wear and seawater corrosion conditions. The results indicated that the tribological performance of the coatings is influenced by factors such as the coating hardness, frictional contacts, and the supporting effect of the substrate. The hardness and elastic modulus of the coatings decreased as the coating thickness increased. A thicker coating results in reduced support from the substrate. The adhesive wear of these coatings under dry sliding wear conditions on the different substrates is also presented. The coefficients of friction (CoFs) of these coatings increased with coating thickness on all three substrates. In contrast, the wear rates decreased as the coating thickness increased. The hardness of the coating was influenced by the support effect of the substrate. The primary factors governing the tribological performance of the coating under dry sliding conditions are the pinch action of the hard grinding ball against the soft coating on the hard substrate and the contact pressure. Abrasive wear, spalling wear, plough grooves, and spalling pits were observed under seawater corrosion conditions. These findings suggest that increased coating thickness is associated with lower coefficients of friction (CoFs) and wear rates. The main contributing factors are seawater corrosion and the scouring effect of high-frequency reciprocating friction.

Optimization of the Camellia oleifera Fruit Harvester Engine Compartment Heat Dissipation Based on Temperature Experiments and Airflow Field Simulation

The Camellia oleifera fruit harvester, a specialized agricultural device, is engineered for efficient operation within the densely planted C. oleifera groves of China’s undulating terrains. Its design features a notably small footprint to navigate the constrained spaces between trees. With the enhancement of the functionality and power of the harvester, the engine compartment becomes even more congested. This, while beneficial for performance, complicates heat dissipation and reduces harvesting efficiency. In this study, experiments were initially conducted to collect temperature data from the main heat-generating components and parts susceptible to high temperatures within the harvester’s engine compartment. Subsequently, a 3D model was developed for numerical simulations, leading to the proposal of optimization schemes for the engine compartment’s structure and the validation of these schemes’ feasibility. A comparison of the experimental data, both before and after optimization, revealed a significant reduction in the surface temperatures of components within the engine compartment following optimization. As a result, the heat dissipation of the engine compartment has been greatly optimized. The harvester has demonstrated prolonged normal operation, enhancing the reliability and economy of the harvester.

Experimental study of the effects of a particle filter in front of automotive radiator on its cooling performances and cooling drag

According to the World Health Organization (WHO), air pollution is the single greatest worldwide health risk especially in urban environments. In these areas, the vehicle traffic significantly contributes to the fine dust concentration in the ambient air. While the current legislation focuses mainly on the exhaust emission of vehicles, 85% of the overall fine dust emissions originating from brakes, tires, and road abrasion are not yet regulated. In this context, an integrated particulate filter system fitted into previously unused installation spaces in frontend of a vehicle in front of the radiator allows to compensate a part of the particle emissions of a vehicle try to reach the neutral emission. Add filter is not without consequences for the cooling performances. This study aims to assess the impact of the particulate filter system on the radiator cooling performances and cooling drag coefficient. An experimental setup was developed to characterize an automotive radiator with and without particle filter in terms of power and velocity distribution. Cooling capacity of the radiator depends clearly of the airflow through the radiator. Filter increases the pressure drop and decreases airflow. Hence, the heat power exchange can be reduced up to 10% for a pressure drop level almost twice. The airflow inlet inside engine compartment is not beneficial for aerodynamic aspect. By increasing pressure drop, the cooling drag coefficient can be reduced up to 10% when a filter covers entirely the radiator surface. The results indicate that the filter affects the cooling capacity of the radiator, which can require modifications to the cooling system strategy.

Influence of emissivity on infrared camouflage performance

The rapid development of infrared detection technology has generated an urgent demand for infrared camouflage, sparking widespread interest in low-emissivity materials. Novel material designs and advanced micro/nanofabrication technologies make it possible to realize materials with extremely low emissivity. However, a lower infrared emissivity does not always mean a better camouflage performance. There is a lack of sufficient discussion on how to determine an appropriate emissivity for a specific working condition to achieve effective infrared camouflage. Here, through outdoor experiments, we demonstrated that for a specific scenario, an appropriate emissivity always exists that can make the infrared characteristics of the target effectively blend into its background, and deviations from the emissivity result in deteriorated camouflage performance. Further, we established a heat transfer model to conduct quantitative analysis on the influence of emissivity on infrared camouflage performance in terms of surface temperature and radiative temperature in various conditions. In addition, we proposed a general method for determining the optimal emissivity of infrared camouflage, defined as the emissivity value at which the radiative temperatures of the target and the background are equal. To facilitate practical application of this method, we developed a user-friendly MATLAB app named “Optimal Emissivity Calculator” to calculate the optimal emissivity. It was found that for a vehicle’s engine compartment surface at approximately 340.0 K, the optimal emissivity is 0.4 with a background temperature of 300.0 K. This work highlights the significance of selecting appropriate emissivity for infrared camouflage and provides a reference for designing the emissivity of infrared camouflage materials.

Assessment of the endurance limit of light structural metal components using the fatigue surface development method

The paper presents a numerical method developed by the authors. The method consists in obtaining a three-dimensional component fatigue surface model according to the results of tests corresponding to two to four values of the operational factor, making it possible to plot the fatigue limit – operational parameter curve. A description of the algorithm of the method is presented, its validity is confirmed. The results show good agreement with outside empirical data for other values of the operational parameters. A model of the fatigue surface is constructed. The model specifies the calculation of strength of aircraft elements operating in rarified atmosphere (e.g. engine compartments of space complexes and upper stages of carrier rockets). The model increases the endurance calculation accuracy and enables structural mass optimization.

Determination of stresses in dangerous cross-sections of frame spars of minitractor vehicles

Problem. On the basis of the method of initial parameters, it is necessary to determine the mass-dimensional parameters of the frame of the spar type, for the creation of a universal small-sized vehicle UMTZ-26 "Nadia", as well as for the development of a mini-truck of category N1, with a carrying capacity of up to 3.2 tons. Goal. To determine the value of the maximum forces (stresses) and moments acting in the structural elements of the spar frame during the arrangement of the engine with transmission, body, engine compartment and cabin of the UMTZ-26 "Nadia" light vehicle, as well as units and aggregates of the N1 category, which can be used for municipal city or farm purpose. Results. According to the given calculation using the method of initial parameters (for frame structures), the maximum load in the cross section of the selected channel is determined, which does not exceed 106.372 MPa, the latter is used as a spar in the welded frame of the vehicle. The maximum permissible load that this profile of the channel can withstand is 160 MPa. Originality. The drawing and design documentation of the spar type was developed, which was used for the development of new universal small-sized vehicles of the UMTZ-26 "Nadia" type, as well as for the creation of mini trucks of the N1 category. Practical value. The practical value lies in the fact that the values of the maximum forces and moments acting in the side members of the frame when the engine with transmission, the engine compartment and the cabin of the vehicle are arranged on it do not exceed the maximum permissible values and the latter can be used on mini motor vehicles of category N1.

Particle swarm optimization for a hybrid freight train powered by hydrogen or ammonia solid oxide fuel cells

All diesel-only trains in the UK will be phased out by 2040. Hydrogen and ammonia emerge as alternative zero-carbon fuel for greener railway. Solid Oxide Fuel Cells (SOFCs) provide an alternative prime mover option, which efficiently convert zero-carbon fuels into electricity without emitting nitrogen oxides (NOx), unlike traditional engines. Superior to Proton Exchange Membrane Fuel Cells (PEMFCs) in efficiency, SOFCs fulfil MW-scale power needs and can use ammonia directly. This study investigates innovative strategies for integrating SOFCs into hybrid rail powertrains using hydrogen or ammonia. Utilizing an optimization framework incorporating Particle Swarm Optimization (PSO), the study aims to minimize operational costs while considering capital and replacement expenditures, powertrain performance, and component sizing. The findings suggest that hybrid powertrains based on ammonia-fueled SOFCs may potentially reduce costs by 30% compared to their hydrogen counterparts, albeit requiring additional space for engine compartments. Ammonia-fueled SOFCs trains also exhibit a 5% higher efficiency at End-of-Life (EoL), showing less performance degradation than those powered by hydrogen. The State of Charge (SoC) of the batteries in range of 30–70% for both cases is identified as most cost-effective.

Analysis sedan vehicle structure in frontal impact using computer model

This paper presents an overview of Sedan vehicle structure based on frontal impact. The analysis results include parameters on the degree of deformation, the collision absorption ability of the Sedan vehicle structural model in accidents. The purpose is based on the comparison results to simulate the Sedan vehicle structure model that collides with other car chassis models at different speed levels, based on that, compares the crash analysis simulations to find the textures the frame absorbs the maximum impact energy and minimizes the deformation so as not to affect intrusion into the safe space of the passenger compartment of the vehicle. The results of this paper show that the frame structures such as the A-Pillars and Horizontal brace between the engine compartment and the passenger compartment need to be improved to increase the safety for the passengers inside. The study results are expected to be expanded in to optimize the engineering structures and improve the efficiency in various fields included shipbuilding, offshore structures, marine aquaculture structures, etc. Keywords: Structural, analysis, Sedan, vehicle structure, fontal impact.

Multi-criteria structural optimization of a hood inner structure using machine learning technique

This article presents an efficient multi-criteria structural optimization process based on machine learning for shape and size optimization of the hood inner. For this purpose, a low dimensional parameterization based on two-dimensional mapping and dimensionality reduction is used to decrease the number of design variables. There are many design parameters to be considered for designing this structure. In this study, the effect of three important criteria consisting of head injury, eigenfrequency, and static load were analyzed. A full vehicle finite element model is prepared for a newly developed product because head injury analysis requires a full vehicle model due to contact with the inner components of the engine compartment. Then, an experimental study is performed based on the real test scenario for model verification. A new rating method for analyzing the head injury criteria evaluated in different points is proposed and different machine learning techniques are compared in the approximation of the objective function. Finally, the problem is solved as both single and multi-objective optimization problems. Results present considerable improvement in accuracy and efficiency in the identified structure while the method has a low computational cost and the implementation is not difficult.

Експериментальні дослідження параметрів мікроклімату в салоні автобуса в холодну пору року

The paper analyzes the current state of research on microclimate parameters in bus cabins and identifies the main issues of the given topic. The authors analyzed and explained the importance of ensuring a favorable microclimate in vehicle cabins and assessed the risks of non-compliance. The relevance of the topic is confirmed by the existing scientific publications of foreign scientists who worked in this field and investigated similar issues. In addition to scientific works, an analysis of regulatory documentation in the world and Ukraine was conducted, existing problems and conflicts in requirements and parameters were considered. Theoretical knowledge is supplemented by experimental studies - the technical characteristics of the investigated bus are shown and the essence of the experiment is presented. Experimental studies were carried out in the passenger compartment of the Ukrainian-made Electron A18501 bus. Microclimate parameters such as temperature, humidity, and the amount of air throughout the passenger compartment in the cold season were measured using special equipment. Measurements were taken in the front, middle and rear of the bus cabin. A total of 4 conditional measurement zones were defined: zone 1 (between the wall of the driver's cabin and the passengers’ platform), zone 2 (in the area of the passengers’ platform), zone 3 (between the passengers’ platform and the rear door) and zone 4 (in the area of the rear door and the engine compartment), where the temperature and air humidity were determined at specific points. Measurements of the amount of air coming from the heating equipment (diffusers) were also made in certain locations. Analyzing the regulatory documents, in particular those used in our country, it was established that air temperature and humidity should be measured at the level of the feet and heads of passengers. There is no need to take measurements at waist level in vehicle cabins, unlike the driver's cabin, unless the bus is operated in very cold or very hot conditions. Since the climate in Ukraine is moderate, there is no need to carry out such additional measurements. The bus traveled along the route Ryasne 1-Levandivka-Sknyliv in Lviv during the experiment. This route fully corresponds to the city bus driving cycle, and its length is comparable to the value of the average city bus route. As a result of the experiment, it was determined that there are specific points in the cabin where the parameters of the microclimate do not correspond to the normative ones. These identified shortcomings require further research in order to improve the comfort of the microclimatic conditions in the bus cabin.

НАУЧНЫЕ ОСНОВЫ ПРЕДУПРЕЖДЕНИЯ ВОЗГОРАНИЯ АВТОМОБИЛЬНЫХ НЕЙТРАЛИЗАТОРОВ В ЭКСПЛУАТАЦИИ

The issue of physical and mathematical representation of the thermal dynamics (kinetics) of the process of conversion of exhaust gases in a catalytic converter in dangerous, from the point of view of fire, uncontrolled emergency operating modes of its operation
 is considered. Modern automobile engines are required to ensure fire safety. On engines with converters, this conflicts with stringent international environmental standards, the satisfaction of which requires the dangerously heated converter to be placed in the engine compartment next to flammable combustible materials. It is proposed to solve the problematic issue by monitoring and diagnosing fire and emergency operating conditions of neutralizers in an in-place method, scientifically substantiated on an interdisciplinary basis – by analyzing the composition of the exhaust gases. The method has been positively tested under real operating conditions.

A computational method to study heat transfer in a helicopter turboshaft engine compartment for waste energy recovery purposes

It is important to take action to make aviation more energy-efficient and less pollutant. One of the approaches currently under development is waste energy recovery. This would be specially advantageous in turboshaft engines, which present an exhaust flow that is not being used for propulsive purposes and with high thermal residual energy that increases infrared signature of helicopters.To evaluate where to locate waste energy recovery devices such as thermoelectric generators or organic Rankine cycles the following is needed: temperatures of exhaust gas flow temperature and exhaust ducts wall temperature, i.e. hot source temperature, and engine compartment temperature, i.e. heat sink temperature. This variables are usually not known beforehand. The present paper develops a method that, with minimal data input, translates flight conditions and engine operation into conditions inside the engine compartment that are later applied to obtain heat transfer in the exhaust ducts, where the waste energy recovery should take place to minimize the influence on the engine. The procedure is based on an algorithm that uses Computational Fluid Dynamics (CFD) simulations validated with experiments.The main findings of this work are: (i) cruise flight velocity has minimal impact on engine compartment temperatures, but hover operation increases it by 5–16 K, (ii) cruise altitude significantly affects engine compartment temperature, with a 12 K difference between 2500 ft and 10000 ft, (iii) considering only the axial component of velocity in exhaust ducts may underestimate wall temperature, (iv) heat transfer in exhaust ducts can be estimated using empirical correlations for natural convection, multiplied by a specific factor, (v) non-invasive methods can recover 23.6 to 31.2 kW of heat from exhaust duct walls, potentially converting up to half of it into useful work.

Automatic fire extinguishing system of the engine compartment of the car

The article discusses the statistics of vehicle ignition, the existing number of fire safety devices, their advantages and disadvantages. A technical solution is proposed based on the use of a dispersant sprayer, which allows mixing various chemicals into a ready-made fire extinguishing mixture, ejecting and spraying within a single process on the ignition source that has arisen in the engine compartment of the car. Keywords car safety, vehicle fires, engine compartment, statistics of car fires, fire extinguishing devices, dispersant sprayer, new technical solution

Risks of the manufacturer of tanks for the transport of liquid dangerous goods by road

The article discusses the statistics of vehicle ignition, the existing number of fire safety devices, their advantages and disadvantages. A technical solution is proposed based on the use of a dispersant sprayer, which allows mixing various chemicals into a ready-made fire extinguishing mixture, ejecting and spraying within a single process on the ignition source that has arisen in the engine compartment of the car. Keywords dangerous goods, road safety, ADR, tank trucks

Thermal Analysis of Pins and Plate Fin Profiles by using Ansys

The engine compartment is one of the essential components of the engine exposed to excessive temperature differences and thermal stress. Fins are positioned on the surface of the cylinder to improve heat exchange by convection. The present study concerns the study of heat exchange between plate fins and pin fins. Pin fins assembled in two shapes (circular, rectangular) with tubular section to allow better improvement of the heat exchange rate. We have optimized the heat exchange rate and optimized all perspectives to achieve a higher heat exchange rate. In the present work, experiments were conducted to determine the temperature fluctuations inside the fins fabricated in three types of geometries (plate fins, circular pin fins, and rectangular pin fins) and study the coherent-state heat transfer was used using ANSYS finite element software to test and approve the results. Temperature fluctuations in different areas of the pin fins are evaluated using FEM, and the plate fin results are compared with the experimentally determined pin fin results in Ansys. The principle implemented in this design is to increase the heat dissipation rate by using wind flow. The main objective of the study is to improve the thermal properties by modifying the geometry, material and design of the fins

Optimized Design of an Ultrasonic-Based High-Efficiency Wireless Passive Monitoring System for Sealed Metal Compartments.

The condition monitoring (CM) of sealed metal compartments (SMCs) is an urgently required restructure. Ultrasound penetrates SMCs to power and communicate with built-in sensors, enabling the CM of SMCs. However, current ultrasonic wireless power transfer and data communication (UWPTADC) systems are large and complex, and limited by the efficiency of energy transfer and data reliability. In this paper, an optimized design of a high-efficiency wireless passive monitoring system using UWPTADC techniques is proposed for SMC. The circuit model of the system is developed and analyzed to achieve an optimal design for efficient wireless power transfer and effective data communication coupling. A test system was constructed using a steel wall of 11 mm thickness as a validation object. At the ultrasonic carrier frequency of 1.045 MHz, the system has an energy transfer efficiency of 60%, and a communication rate of 50 kbps. In addition, the system realizes temperature and humidity monitoring inside a 13 mm thick cylindrical SMC, simulating the process of ultrasonic CM of an actual engine compartment. The system provides a wiring-free and battery-free solution for CM in SMCs, advancing CM in aerospace, marine and other fields.

Ventilation effect on the fire behavior in a vehicle engine compartment

Ventilation effect on the fire behavior in a vehicle engine compartment

A Review of Nanofluids as Coolants for Thermal Management Systems in Fuel Cell Vehicles.

With the development of high-power fuel cell vehicles, heat dissipation requirements have become increasingly stringent. Although conventional cooling techniques improve the heat dissipation capacity by increasing the fan rotating speed or radiator dimensions, high energy consumption and limited engine compartment space prevent their implementation. Moreover, the insufficient heat transfer capacity of existing coolants limits the enhancement of heat dissipation performance. Therefore, exploring novel coolants to replace traditional coolants is important. Nanofluids composed of nanoparticles and base liquids are promising alternatives, effectively improving the heat transfer capacity of the base liquid. However, challenges remain that prevent their use in fuel cell vehicles. These include issues regarding the nanofluid stability and cleaning, erosion and abrasion, thermal conductivity, and electrical conductivity. In this review, we summarize the nanofluid applications in oil-fueled, electric, and fuel cell vehicles. Subsequently, we provide a comprehensive literature review of the challenges and future research directions of nanofluids as coolants in fuel cell vehicles. This review demonstrates the potential of nanofluids as an alternative thermal management system that can facilitate transition toward a low-carbon, energy-secure economy. It will serve as a reference for researchers to focus on new areas that could drive the field forward.

Anti-contamination calibration method for ultra-fine dry chemical agent: Achieving wide measurement range and high measurement accuracy

Achieving real-time measurements of ultra-fine dry chemical agents (UDCA) is extremely challenging, with their complex composition, high injection concentrations, and susceptibility to contamination. In this study, a high-concentration particulate matter measurement method was proposed based on the extinction principle to reduce the powder contamination effect during calibrations. Through theoretical analysis and experimental verification, a functional relationship was established. Calibration experiments were conducted using sodium bicarbonate (SBA) and potassium bicarbonate (PBA) UDCAs, which are the most representative. The results showed that the measurement ranges of SBA and PBA reached 227.15 g/m3 and 122.55 g/m3, respectively. Compared with the uncorrected calibration method, the maximum indicated errors of SBA and PBA with the powder contamination effect corrected were reduced from 11.25% and 22.68% to 5.98% and 9.21%. This method provides a strategy for measuring high concentration powder, especially for achieving the measurement of UDCA in aircraft engine compartments.

Working process and opening characteristics of soft insulator of pulse motor

AbstractIn this paper, a simulation test system for the working process of soft insulation is designed, using equivalent simulated ablation test methods combined with a CCD measuring system and micro electron microscope scanning technology, which can better describe the thermal properties and state of insulation after ablation. At the same time, a test plan for the opening characteristics of the insulator based on different ablation times and different opening structure sizes as the main influencing factors are designed. The experimental results show that the ablation test can well simulate the state of an actual pulse engine compartment after the ablation and the maximum relative error of the ablation rate can be controlled within 5 %. From the influence of ablation time on the opening characteristics of the insulator, it can be seen that the maximum axial deformation of the insulator is different from the relative value of the opening pressure. The radial deformation of the insulator is larger than that of the non‐ablated insulator and larger than the inner diameter of the insulator shell after ablation. From the influence of the size of the opening structure of the insulator (depth of weakening grooves) on the opening characteristics of the insulator, it can be seen that as the weakening groove depth of the compartment deepens, the original pressure change pattern disappears, and the opening pressure and opening time of the insulator decrease significantly.