Electric vehicles are affected by various factors such as the ambient temperature, traffic conditions, driver behavior, vehicle weight, and route characteristics. This study evaluated the energy ...efficiency of an electric SUV with regenerative braking system under real-world driving conditions. Data were collected using a controller area network while driving on the same route at each regenerative braking stage. Chassis dynamometer tests were performed to verify battery consumption during acceleration and regenerative braking. From the real-world driving test, it was determined that as the regenerative braking stage increased, the battery consumption (excluding regenerative braking) and energy recovered. However, the net battery consumption decreased. In addition, as the speed increased, the energy consumption increased in the order of urban, rural, and motorway sections owing to the air resistance and rolling resistance. Although the energy efficiency tended to increase with the regenerative braking stage, we observed that the real-world driving environment also had an impact. Therefore, in energy efficiency evaluation research, it is essential to analyze the results that reflect the various influencing factors in real-world driving environments and to verify the characteristics of each regenerative braking stage through chassis dynamometer tests.
•Real-world testing of regenerative braking stages shows improved energy efficiency in electric vehicles.•Higher regenerative braking stages lead to greater energy recovery and reduced net energy consumption.•Energy efficiency varies with driving conditions, such as speed and traffic volume.•Further research is needed to quantify the effects of various parameters on EV energy efficiency.
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•The impact of ambient temperature was analyzed using the chassis dynamometer and real-world driving.•It shows good performance at an ambient temperature approximately (20 to 30) ...℃.•Ambient temperature affects energy recovery, with battery consumption increasing by 35.4 % when compared to −15 ℃ as opposed to 24 ℃.•Real-world driving shows higher efficiency than certified range.
Electric vehicles are affected by ambient temperature, which is closely related to the driving range. This study conducted a comprehensive evaluation of the energy efficiency using both a chassis dynamometer and actual driving environments. Under various temperature conditions, the motor energy, battery energy, regenerative energy, and energy efficiency were analyzed using a Combination US06 mode of the chassis dynamometer and the Konkuk University route to realize real-world driving scenario. The results revealed that low temperatures increased the motor and battery energy consumptions (compared to 24 ℃ ambient temperature, −15 ℃ required 35.4 % more.) while hindering regenerative energy recovery during driving. This study confirmed that the optimal energy efficiency for electric vehicles is attained at approximately (20 to 30) ℃. Notably, the energy efficiencies were real- higher than the certified values under real-world driving conditions. Moreover, when the HVAC system is turned on, it increases battery energy consumption by 5.4 % in the summer and by 12.0 % in the winter, influencing the overall energy efficiency with higher battery energy consumption during its operation in both seasons. Therefore, the study findings highlight the importance of considering the ambient temperature and HVAC system usage when evaluating vehicle energy efficiency and driving range. Furthermore, this study emphasizes the need for future vehicle designs and energy management systems to optimize the performance under various ambient conditions, thereby enhancing the overall energy efficiency and extending the driving range.
•Since 2018, NOx of 132 Euro-6 LDVs certified in Korea was studied.•NOx according to after-treatment devices and control strategies was analyzed.•Accelerator pedal operation and EGR ratio have a ...direct impact on NOx.•In acceleration condition, the fuel amount and λ signal affect to NOx emission.
This study used emission certification data for vehicles that met Korea's Euro-6 emission standards after 2018. It was analyzed that the distribution of nitrogen oxide (NOX) emission in accordance with the type of after-treatment system under cold and hot start conditions by classifying domestic and imported cars. In addition, the relationship between electronic control unit (ECU)/dosing control unit (DCU) signals and exhaust emissions were analyzed under NEDC and WLTP driving mode conditions. Three models of vehicles equipped with different after-treatment systems were selected among the vehicles subject to the 2019 real road driving test for this study. And it was acquired that ECU and DCU signals, which are expected to be related to emissions as well as emissions. In order to satisfy Euro-6, the LNT + SCR after-treatment system was applied to more than 76% of vehicle models. Among ECU signals, there was a direct relationship between the accelerator pedal and the EGR valve opening degree, and there was a deviation depending on the driving mode. Among the DCU signals, the catalyst temperature, urea-water injection quantity, and injection timing are controlled in accordance with the NOX emission measured by the sensor. In the future, it is necessary to analyze the correlation between the ECU signal and the DCU signal to derive a factor that can be used as a measure to suspect defeat devices.
Abstract The capability to spatially control stem cell orientation and differentiation simultaneously using a combination of geometric cues that mimic structural aspects of native extracellular ...matrix (ECM) and biochemical cues such as ECM-bound growth factors (GFs) is important for understanding the organization and function of musculoskeletal tissues. Herein, oriented sub-micron fibers, which are morphologically similar to musculoskeletal ECM, were spatially patterned with GFs using an inkjet-based bioprinter to create geometric and biochemical cues that direct musculoskeletal cell alignment and differentiation in vitro in registration with fiber orientation and printed patterns, respectively. Sub-micron polystyrene fibers (diameter ∼ 655 nm) were fabricated using a Spinneret-based Tunable Engineered Parameters (STEP) technique and coated with serum or fibrin. The fibers were subsequently patterned with tendon-promoting fibroblast growth factor-2 (FGF-2) or bone-promoting bone morphogenetic protein-2 (BMP-2) prior to seeding with mouse C2C12 myoblasts or C3H10T1/2 mesenchymal fibroblasts. Unprinted regions of STEP fibers showed myocyte differentiation while printed FGF-2 and BMP-2 patterns promoted tenocyte and osteoblast fates, respectively, and inhibited myocyte differentiation. Additionally, cells aligned along the fiber length. Functionalizing oriented sub-micron fibers with printed GFs provides instructive cues to spatially control cell fate and alignment to mimic native tissue organization and may have applications in regenerative medicine.
Serious climate changes and energy-related environmental problems are currently critical issues in the world. In order to reduce carbon emissions and save our environment, renewable energy harvesting ...technologies will serve as a key solution in the near future. Among them, triboelectric nanogenerators (TENGs), which is one of the most promising mechanical energy harvesters by means of contact electrification phenomenon, are explosively developing due to abundant wasting mechanical energy sources and a number of superior advantages in a wide availability and selection of materials, relatively simple device configurations, and low-cost processing. Significant experimental and theoretical efforts have been achieved toward understanding fundamental behaviors and a wide range of demonstrations since its report in 2012. As a result, considerable technological advancement has been exhibited and it advances the timeline of achievement in the proposed roadmap. Now, the technology has reached the stage of prototype development with verification of performance beyond the lab scale environment toward its commercialization. In this review, distinguished authors in the world worked together to summarize the state of the art in theory, materials, devices, systems, circuits, and applications in TENG fields. The great research achievements of researchers in this field around the world over the past decade are expected to play a major role in coming to fruition of unexpectedly accelerated technological advances over the next decade.
Managing interfacial instability is crucial for enhancing cyclability in lithium-ion batteries (LIBs), yet little attention has been devoted to this issue until recently. Here, we introduce graphene ...as an interfacial layer between the current collector and the anode composed of Si nanowires (SiNWs) to improve the cycling capability of LIBs. The atomically thin graphene lessened the stress accumulated by volumetric mismatch and inhibited interfacial reactions that would accelerate the fatigue of Si anodes. By simply incorporating graphene at the interface, we demonstrated significantly enhanced cycling stability for SiNW-based LIB anodes, with retentions of more than 2400 mAh/g specific charge capacity over 200 cycles, 2.7 times that of SiNWs on a bare current collector.
Passenger cars account for the largest share of GHG emissions in the road sector. However, given that the number of heavy-duty vehicles registered is lower but accounts for about a quarter of GHG ...emissions in the road sector, it is necessary to reduce carbon dioxide (CO2) emissions by improving the fuel efficiency of heavy-duty vehicles. However, experiments using dynamometers during the vehicle development process consume a lot of time and cost. Conversely, simulations can quantitatively analyze the sensitivity of parameters and accelerate optimization. Therefore, in this study, we modeled a heavy-duty vehicle using an AVL Cruise simulation and analyzed the effects of payload, air drag coefficient, and rolling resistance on fuel economy, CO2 emission, and the valid window ratio among the moving average window (MAW) for three driving routes. When the average vehicle speed was higher, the effect of the air drag coefficient on fuel economy was high. Additionally, when the average vehicle speed was lowered, the effect of the reduced rolling resistance on improving fuel efficiency was higher than that of the reducing air drag. Thus, the fuel efficiency improvement rate according to each 10% decrease in rolling resistance was higher by 2.2%, on average, in the low average speed route. Additionally, it was confirmed that the valid window ratio was high when driving in a section with a high vehicle speed first. Thus, the valid window ratio was almost 100% in the test of the route conditions starting from the highway section.
•Diesel/ethanol RCCI combustion simultaneously reduces NOx and PM.•The IMEPnet increases as the ethanol supplied ratio increases for early injection.•RCCI combustion increases the thermal efficiency ...with reduction in the heat transfer and exhaust losses.•The increase in the intake air temperature retards the optimal injection timing.•The higher the intake air temperature, the higher the increase in the diesel supply ratio.
The reactivity controlled compression ignition (RCCI) combustion has the potential to simultaneously reduce the NOX and PM emissions and maintain combustion performance even when injection timing is advanced. Because intake air temperature is an important factor affecting the reactivity of fuels, it is necessary to study optimized fuel supply ratios according to the intake air temperature. Therefore, the purpose of this study was to analyze combustion and exhaust characteristics in relation to the fuel supply ratio, injection timing, and intake air temperature. In this study, ethanol was injected into an intake port; increasing the ethanol supplied ratio increased the ignition delay. Thus, the net indicated mean effective pressure (IMEPnet), compared with conventional diesel combustion, increased from 4.14 to 4.90 bar for the advanced injection timing (BTDC 27°). In addition, because the combustion period was lengthened and combustion temperature lowered, the NOX emission decreased (19.1 → 2.7 g/kWh); however, the THC (1.1 → 2.5 g/kWh) and CO (5.2 → 10.1 g/kWh) emissions increased. Moreover, burning an homogeneous mixture of ethanol decreased the particulate matter emission from 74 to 45 μg/m3. However, under high intake air temperature conditions, the effect of ethanol ratio on ignition delay was small. Therefore, the injection timing at which the maximum IMEPnet occurred was retarded. In addition, as the intake air temperature increased, the THC and CO emissions decreased and that of NOX increased.
Osteoclasts (OCs), cells specialized for bone resorption, are generated from monocyte/macrophage precursors by a differentiation process governed by RANKL. Here, we show that DCTN1, a key component ...of the dynactin complex, plays important roles in OC differentiation. The expression of DCTN1 was upregulated by RANKL. The inhibition of DCTN1 expression by gene knockdown suppressed OC formation, bone resorption, and the induction of NFATc1 and c-Fos, critical transcription factors for osteoclastogenesis. More importantly, the activation of Cdc42 by RANKL was inhibited upon DCTN1 silencing. The forced expression of constitutively active Cdc42 restored the OC differentiation of precursors with DCTN1 deletion. In addition, PAK2 was found to be activated by RANKL and to function downstream of Cdc42. The DCTN1-Cdc42 axis also inhibited apoptosis and caspase-3 activation. Furthermore, the anti-osteoclastogenic effect of DCTN1 knockdown was verified in an animal model of bone erosion. Intriguingly, DCTN1 overexpression was also detrimental to OC differentiation, suggesting that DCTN1 should be regulated at the appropriate level for effective osteoclastogenesis. Collectively, our results reveal that DCTN1 participates in the activation of Cdc42/PAK2 signaling and the inhibition of apoptosis during osteoclastogenesis.
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