Implementation of a 3.5 kW resistive load bank for a single-cylinder diesel engine test bench

This report, entitled Novel Injector Techniques for Coal-Fueled Diesel Engines,'' describes the progress and findings of a research program aimed at development of a dry coal powder fuel injector in conjunction with the Thermal Ignition Combustion System (TICS) concept to achieve autoignition of dry powdered coal in a single-cylinder high speed diesel engine. The basic program consisted of concept selection, analysis and design, bench testing and single cylinder engine testing. The coal injector concept which was selected was a one moving part dry-coal-powder injector utilizing air blast injection. Adiabatics has had previous experience running high speed diesel engines on both direct injected directed coal-water-slurry (CWS) fuel and also with dry coal powder aspirated into the intake air. The Thermal Ignition Combustion System successfully ignited these fuels at all speeds and loads without requiring auxiliary ignition energy such as pilot diesel fuel, heated intake air or glow or spark plugs. Based upon this prior experience, it was shown that the highest efficiency and fastest combustion was with the dry coal, but that the use of aspiration of coal resulted in excessive coal migration into the engine lubrication system. Based upon a desire of DOE to utilize a more modern test engine, the previous naturally-aspirated Caterpillar model 1Y73 single cylinder engine was replaced with a turbocharged (by use of shop air compressor and back pressure control valve) single cylinder version of the Cummins model 855 engine.

<div class="section abstract"><div class="htmlview paragraph">The increased availability of natural gas (NG) in the United States (US) and its relatively low cost compared to diesel fuel has heightened interest in the conversion of medium duty (MD) and heavy duty (HD) engines to NG fueled combustion systems. The aim for development for these NG engines is to realize fuel cost savings and reduce harmful emissions while maintaining durability. Transforming part of the vehicle fleet to NG is a path to reduce dependence on crude oil.</div><div class="htmlview paragraph">Traditionally, port-fuel injection (PFI) or premixed NG spark-ignited (SI) combustion systems have been used for MD and HD engines with widespread use in the US and Europe. But this technology exhibits poor cycle efficiency and is load limited due to knock phenomenon. Direct Injection of NG during the compression stroke promises to deliver improved thermal efficiency by avoiding excessive premixing and extending the lean limits which helps to extend the knock limit.</div><div class="htmlview paragraph">In this work, a single cylinder engine with 14:1 compression ratio (CR) was used to investigate spark ignited direct injection (SIDI) NG combustion using an integrated spark injector-igniter. Two parameters controlling dilution were investigated (i) increased air charge resulting in an increased air-fuel ratio (AFR) and (ii) exhaust gas recirculation (EGR). The impact of these parameters on fuel consumption, combustion stability, phasing, knock, and emissions of NOx, HC, CO is investigated and reported in this work. Partially stratified combustion (PSC) SOI and SPK timings from previous work will be used as a starting point to investigate the effects. Overall, both AFR and EGR were effective in controlling knock and NOx emissions; however, EGR required lower levels to obtain the desired effect. The use of charge dilution in the PSC range showed promise of trading off knock and combustion stability to within acceptable limits, thus demonstrating potential for increased load operation.</div></div>

Biological pollution creates significant obstacles in the operation of power plants' technical water supply cooling systems (SCS). To minimize biological pollution, methods of corrective treatment with biocides are implemented. While these biocides effectively prevent fouling of the cooling system, they can also adversely affect the environment and structural materials. By evaluating structural materials' corrosion resistance and biocides' environmental safety for the cooling water during biocide treatment, any potential issues can be identified and addressed before they become a safety or operational concern. The paper presents the results of bench tests of the corrosion resistance of structural materials SCS, corrosion aggressiveness of the biocides: sodium hypochlorite NaClO and 2, 2-dibromo-3-nitriloropionamide (DBNPA), and the results of measurements of the concentration of biocides and their decomposition products to assess compliance with environmental standards when discharging return water when applying from biocides treatment. The cooling water SCS of the Rivne NPP (Nuclear Power Plant) was chosen as the research object. Bench corrosion tests were carried out using samples of corrosion indicators from materials: steels Ст20, 08Х18Н10Т; copper alloy МНЖ-5-1 and aluminum, which are defined as analogs of structural materials of the technical water supply system of the Rivne NPP. The conditions of operation of the technical water SCS of the Rivne NPP were simulated on the test bench, and corrosion rate measurement was carried out by the gravimetric method.

This paper follows on from an earlier publication on high-blend-rate binary gasoline-alcohol mixtures and reports results for some equivalent ternary fuels from several investigation streams. In the present work, new findings are presented for high-load operation in a dedicated boosted multi-cylinder engine test facility, for operation in modified production engines, for knock performance in a single-cylinder test engine, and for exhaust particulate emissions at part load using both the prototype multi-cylinder engine and a separate single-cylinder engine. The wide variety of test engines employed have several differences, including their fuel delivery strategies. This range of engine specifications is considered beneficial with regard to the “drop-in fuel” conjecture, since the results presented here bear out the contention, already established in the literature, that when specified according to the known ternary blending rules, such fuels fundamentally perform identically to their binary equivalents in terms of engine performance, and outperform standard gasolines in terms of efficiency. However, in the present work, some differences in particulate emissions performance in direct-injection engines have been found at light load for the tested fuels, with a slight increase in particulate number observed with higher methanol contents than lower. A hypothesis is developed to explain this result but in general it was found that these fuels do not significantly affect PN emissions from such engines. As a result, this investigation supplies further evidence that renewable fuels can be introduced simply into the existing vehicle fleet, with the inherent backwards compatibility that this brings too.

<div class="section abstract"><div class="htmlview paragraph">The reduction of exhaust emissions and particulate matter from internal combustion engines remains a critical challenge, particularly under cold start and warm-up conditions, where a significant portion of total emissions is generated. In spark-ignition (SI) gasoline engines, the formation of liquid fuel films on intake ports wall, piston and cylinder wall surface significantly contributes to unburned hydrocarbon and particulate emissions. Also, the fuel film adhering to the wall can be a cause of the lubricating oil dilution. To address these issues, a novel capacitive sensor, fabricated using MEMS technology, was developed and applied to investigate the behavior of liquid fuel films formed inside the combustion chamber of a single-cylinder engine. The sensor detects changes in capacitance caused by fuel film adhesion to the sensor surface. The sensor was installed in a single-cylinder test engine along with a direct fuel injector allowing for the controlled formation of fuel films on the sensor surface. Ethanol was used as the injected fuel for film formation due to its higher permittivity compared to iso-octane, the fuel used for engine operation. This choice enhanced the sensor sensitivity to film presence. Four experimental configurations were tested, varying the sensor’s location (intake vs. exhaust side) and whether the ethanol spray directly impinged on the sensor. The engine was operated at 2000 rpm with an intake pressure of 90 kPa. The coolant temperature was varied from 20 °C to 80 °C to simulate cold start and warm-up conditions. The transition from motoring to firing operation was used to replicate transient startup behavior, and the sensor output was monitored cycle-by-cycle. Results showed that the sensor effectively captured the formation and evaporation of the fuel film. Sensor output was significantly higher at locations exposed to direct ethanol spray, particularly at lower coolant temperatures, indicating greater film accumulation. Conversely, positions shielded from the spray exhibited minimal signal variation. Additionally, sensors mounted on the exhaust side showed faster recovery to baseline values, attributed to higher wall temperatures promoting quicker evaporation. In conclusion, the developed capacitive sensor demonstrated high sensitivity and reliability in detecting in-cylinder fuel films under realistic engine conditions. Its compact design and ease of integration make it a promising diagnostic tool for studying fuel film dynamics in production engines.</div></div>

Hierarchical estimation of uncertainties in multi-rotors:A yaw-motion study using test bench

As the interest in environmental issues increases, the cogeneration system has recently been attracting much attention. Particularly, the use of gas engines for cogeneration systems with low emission and high thermal efficiency is now expected to become widespread. For improving thermal efficiency, it is necessary to extend the lean limit and accelerate combustion. In this study, attention was focused on "Pre-chamber Spark Plug", which has a pre-chamber at the tip of the standard plug. We studied the effects of using a pre-chamber spark plug for 300kW to 2MW gas engines with a single-cylinder test engine. By the pre-chamber plug, the lean limit was extended and the thermal efficiency was improved.

<div class="section abstract"><div class="htmlview paragraph">In the quest for reduced cost and shorter development times for fuel cell systems in industrial applications, two major issues arise. First, the electrochemical behavior of fuel cell systems is inherently difficult to predict. Second, testing fuel cell systems is resource intensive. These issues compound: Setting up an accurate model of a fuel cell system incurs long testing periods for model validation. Further, it does not guarantee acceptable results outside the tested range or for other membrane electrode assembly compositions.</div><div class="htmlview paragraph">To mitigate these two major issues an X in the Loop concept is proposed. Essentially, this is the direct integration of the test sample, here a single fuel cell, into the modelling environment of the whole system. In practice, two strategies with different levels of integration are defined.</div><div class="htmlview paragraph">The first strategy consists of initially deducing the operating parameters of the sample cell from the fuel cell system model. Then, setting them to the sample cell in the test bench. The response of the test sample is finally used to validate the designed system or update the parameters of the fuel cell model.</div><div class="htmlview paragraph">The second strategy is a step further towards the integration of the test sample into the model. Here, the core model of the fuel cell inside the fuel cell system model is completely replaced with the test sample, reducing the need for an accurate electrochemical model while improving the prediction of the behavior of the fuel cell system.</div><div class="htmlview paragraph">Compared to previously proposed testing concepts, here the balance of plants is directly integrated through a digital emulator, leading to a closer representation of the complete system. Furthermore, the test bench results are looped back to the model at run-time leading to a closer match between testing conditions and the real world as well a reduced impact of inaccuracies in the modelling of the fuel cell.</div><div class="htmlview paragraph">On the way to realizing this goal, an experimental test bench capable of showcasing working prototypes of the proposed operating strategies has been built.</div></div>

The main annulus hot gas ingress into turbine wheel-spaces is still one of the most challenging problem designers face. During the decades, several experimental test benches were developed worldwide to improve the knowledge associated to the rim seal flow physics. Even if in some cases quite complex and advanced rig configurations were proposed, limitations in the operating conditions and in the reproduction of the real engine geometries/characteristics into the rig are present. In this paper, validated CFD computations are used to explore the impact of some experimental rigs design choices/limitations on the sealing effectiveness prediction and their ability to mimic the real engine configuration behaviour. Attention is paid on several test rig related aspects such as operating conditions, flow path configuration (blade and vane count) and accuracy in the real engine rim seal geometry reconstruction applied to the rig. From the computations it emerges that a scaled geometry operated at lab conditions is able to mimic pretty well the real engine sealing performance when rig and engine experience the same flow path ΔCp. The ability of the rig to match the engine data is not affected by the differences in main annulus Mach number between test bench and engine. A further result that emerges from the computation regards the fact that the Φ0 - ΔCp0.5 curve is not linear, proving that the linear extrapolation of rim sealing performance from test bench to real engine when rig and engine are characterized by different ΔCp0.5 values is not of general application and an alternative approach is given. Finally, it is found that the impact of vane count on the rim sealing effectiveness is significant, making the extrapolation of data from rig to engine difficult.

This paper presents a strategy to emulate a reduced scale of sucker rod pump using laboratory test bench. The strategy is based on combination of software and hardware system. Torque reference is generated using the proposed strategy based on real time model of sucker rod pump that runs in LabVIEW. The output of encoder and torque sensor are integrated through NI PCI- 6221 data acquisition card to the real time platform. The performance of the experimental test bench is evaluated using current, voltage, speed, and torque measurements and power calculations. The experimental results are compared to simulation results. The results indicate the capability of this test bench to serve as a platform for conducting experimental studies on sucker rod pump.

Subject of study. Technology for quantum key distribution in fiber-optic communication lines under the influence of electromagnetic fields generated by atmospheric discharges is studied. Aim of study. A test bench for testing experimental techniques to be used in studying the effect of atmospheric discharges on transmission of a quantum key via fiber-optic communication lines is developed. Method. The characteristics of a quantum communication channel upon exposure of a coil containing an optical fiber to a magnetic field from a pulsed current are experimentally studied. Main results. An experimental test bench has been created and methods have been developed to evaluate the influence of magnetic fields arising from atmospheric discharges (lightning) on the transmission speed of a quantum key in fiber-optic communication lines. It was shown that quantum key distribution blocks using the BB84 phase-encoding protocol continue to show operational stability when the optical cable is exposed to alternating magnetic fields of up to 1.2 mT. However, the very fact of exposure to magnetic fields above 0.8 mT can be detected by a systematic decrease in the quantum key transmission rate and an increase in the quantum bit error rate (QBER) by 0.5%–1%. Practical significance. The laboratory test bench and methods developed herein support magnetic-field testing of various optical cables used for transmission of qubits. Fiber-optic networks through which qubits are transmitted can serve as a distributed lightning sensor; an increase in the level of quantum errors and a decrease in quantum key generation rate will be observed in any segment of an optical network where a lightning discharge generates strong magnetic fields.

A tyre-rim interaction digital twin for biaxial loading conditions

<div class="htmlview paragraph">Hydrogen-supplemented fuel was investigated as a means of extending lean operating limits of gasoline engines for control of NO<sub>x</sub>. Single-cylinder engine tests with small additions of hydrogen to the fuel resulted in very low NO<sub>x</sub> and CO emissions for hydrogen-isooctane mixtures leaner than 0.55 equivalence ratio. Significant thermal efficiency improvements resulted from the extension beyond isooctane lean limit operation. However, HC emissions increased markedly at these lean conditions.</div> <div class="htmlview paragraph">A passenger car was modified to operate at 0.55-0.65 equivalence ratio with supplemental hydrogen. Vehicle emissions, as established by the 1975 Federal Exhaust Emissions Test, demonstrated the same trends as the single-cylinder engine tests.</div> <div class="htmlview paragraph">The success of the hydrogen-supplemented fuel approach will ultimately hinge on the development of both a means of controlling hydrocarbon emissions and a suitable hydrogen source on board the vehicle. Reported efforts to develop a satisfactory onboard hydrogen generator (gasoline reformer) appear restricted by fuel economy considerations.</div>

<div class="section abstract"><div class="htmlview paragraph">CO2 emission constraints taking effect from 2020 lead to further investigations of technologies to lower knock sensitivity of gasoline engines, main limiting factor to increase engine efficiency and thus reduce fuel consumption. Moreover the RDE cycle demands for higher power operation, where fuel enrichment is needed for component protection. To achieve high efficiency, the engine should be run at stoichiometric conditions in order to have better emission control and reduce fuel consumption. Among others, water injection is a promising technology to improve engine combustion efficiency, by mainly reducing knock sensitivity and to keep high conversion rates of the TWC over the whole engine map.</div><div class="htmlview paragraph">The comprehension of multiple thermodynamic effects of water injection through 3D-CFD simulations and their exploitation to enhance the engine combustion efficiency is the main purpose of the analysis. As basis for the research a single cylinder engine derived from a 1l turbocharged 3-cylinders engine is used to evaluate indirect and direct water injection. The entire engine flow field is reproduced and analyzed with 3D-CFD simulations and numerical models are employed to separate the influence of chemical and thermodynamic properties. Measurements are performed with different injectors for indirect/direct water injection in the single-cylinder engine in order to assess water break-up, wall wetting, spray interaction and penetration. Several injection strategies, such as varying start of injection, injection pressure, and water to fuel ratio, are tested at the single-cylinder engine test bench. Detailed gas phase chemistry is employed to link flame front speed with water concentration and knocking occurrence. These results are correlated with the 3D-CFD simulation of mixture formation, in-cylinder flow and water distribution for two different operating points (part load and maximum power) in order to study water behavior, with focus on the evaporation process, in-cylinder pressure and temperature profile, as well as the combustion development, during multiple engine cycles.</div></div>

The aim of this study was to analyze the biomechanical behavior of lower premolars regarding the non-carious cervical lesion (NCCL) depth, load type and restoration status, using finite element analysis. Two-dimensional virtual model simulating a healthy lower premolar were created using the CAD software. Based on this image, five models were generated: healthy (H), three types of NCCLs: small lesion (SL - 0.5 mm deep), medium lesion (ML - 1.0 mm), deep lesion (DL - 1.5 mm), and restored lesion (RL). The models were export to a CAE software (ANSYS Finite Element Analysis Software), the areas of all structures were plotted and each model was meshed using a control mesh device. All of the virtual models were subjected to two occlusal load types, (100N each): occlusal load (OL) and buccal load (BL) on buccal cusp. The magnitude and the stress distribution were obtained using the von Mises and maximum principal stress criteria (σ1), in MPa. The quantitative analysis of stress (MPa) was identified at three points of the NCCLs: enamel surface on its upper wall , dentin at the bottom wall and dentin on the lower wall. The results showed a direct relation between sequential removal of cervical structure and higher stress concentration for any groups and for both loads types. For OL the highest value of stress was 8.8 MPa for DL on upper wall of NCCLs.The BL exhibited higher stress values in comparison to the OL for all models.In addtion, the BL was responsible for providing the highest stress accumulation on the bottom wall, 38.2 MPa for DL. The restoration with composite resin was able to restore a stress distribution close to the healthy model, for both load types. In conclusion, the extent of non-carious cervical lesion and loading conditions influenced the stress distribution pattern of lower premolar. The outer load seems to be more critical in affecting the biomechanical behavior of lower premolars, regardless of the lesion size. The restoration of NCCLs with composite resin appears to recover the biomechanical behavior, similar to healthy model.