Oxyhydrogen, a hydrogen-based fuel, is commonly used to enhance the performance of ethanol-gasoline engines. We experimentally investigated the combustion characteristics and emissions of a multi-fuel combined supply system using oxyhydrogen negative pressure induction, bioethanol direct injection (BEDI), and gasoline port fuel injection. At 1500 rpm and excess air ratio 1, integrated oxyhydrogen technology improves combustion efficiency and significantly reduces CO and HC emissions; however, NOx emissions increase. With increasing BEDI pressure, the indicated mean effective pressure (IMEP) and maximum in-cylinder pressure increase initially and then decrease. CO and HC emissions show a similar trend, decreasing initially and then increasing, while NO is reduced by an average of 14.09%. Advancing BEDI timing benefits the cyclic coefficient of variation of IMEP. When the BEDI timing is within 250-300 degrees CA BTDC, HC, CO, and particulate emissions reach their lowest levels, with particulates decreasing by up to 70.11%.

Hairpin motors had performance advantages such as high thermal conductivity and torque density. The oil spray cooling can efficiently remove the surface heat of the end winding. The combined application of these two technologies can enhance motor power density-a feature already proven in numerous commercial applications. However, there was only a little research related to axial oil spray cooling for end windings. This research evaluated the cooling performance of axial oil spray cooling with varying motor speeds and total flow rates using different nozzle types. Subsequently, the influence of optimizing branch flow rate on cooling performance was investigated when using fan nozzles at different motor speeds. Key findings revealed: (1) Higher flow rates improved cooling uniformity and capacity at the cost of increased pumping power. (2) Elevated motor speeds enhanced cooling uniformity, reducing temperature standard deviation by at most 33.5%. (3) Fan nozzles provided the best overall cooling capacity and uniformity, and consumed moderate pumping power. (4) Compared with the original scheme of 5 L/min, Scheme 1 (also 5 L/min) was used to optimize branch flow rate can improve the overall cooling uniformity, reduce the temperature standard deviation by at most 18.8%, and at least 5.2%, but slightly degraded overall cooling capacity.

Understanding the dynamic characteristics of droplets in the orientated flow channels of Proton Exchange Membrane Fuel Cells (PEMFCs) is crucial for their effective heat and water management and bipolar plate design. Therefore, the transient transport dynamics of liquid water within orientated gas flow channels (OGFCs) of PEMFCs are investigated, and a two-phase model based on the volume of fluid (VOF) method is established in the current study. Moreover, the impacts of the size of droplets and the geometrical parameters of baffles on the removal dynamics of liquid water are examined. The results show that baffles effectively promote droplet breakup and accelerate their detachment from the Gas Diffusion Layer (GDL) surface by increasing flow instability and local shear forces. The morphology of water is altered by the high velocity of gaseous flow, which can break up into several smaller droplets and distribute them on the surface of GDL by the gas flow. The shape of the liquid water film changes from a regular cuboid to a big droplet due to the surface tension of the liquid water droplets and the hydrophobicity of the GDL surfaces. Increasing the baffle height can reduce the time needed for the removal of droplets. With the increase in L1* from 0.25 to 0.75, the drainage time decreases slightly; however, for L1* increasing from 0.75 to 1.25, the drainage time remains almost the same. The impacts of different leeward lengths, L2*, on the water coverage ratio and pressure drop are minor.

Proton exchange membrane fuel cell (PEMFC) systems exhibit complex dynamic nonlinearities and multitimescale coupling effects, challenging traditional physics-based modeling. To improve modeling accuracy and adaptability, this article proposes a multitask deep learning modeling framework based on the temporal pattern attention mechanism and long short-term memory (Multi-LSTM-TPA) networks, providing an end-to-end dynamic modeling solution for PEMFC systems. Through a feature-response grouping method based on subsystem control logic and electrochemical coupling mechanism, the model internally implements independent training and updates of multiple subtasks. The TPA mechanism dynamically optimizes the weights of the LSTM across different time steps, effectively capturing the dynamic characteristics at various timescales. The 70-30 train-test split demonstrated an optimal trade-off between training cost and prediction accuracy, achieving 95.2% regression accuracy on the test set while showing high robustness against ratio variations. A PCA-based projection compression method was developed, which reduced memory usage by 88% while maintaining comparable accuracy, thereby enhancing computational efficiency and reducing deployment complexity. Finally, the model's high-fidelity representation and practical utility were validated through Simulink simulations.

To explore the synergistic application of advanced combustion technologies and renewable fuels, aiming to achieve more efficient engine performance, lower emissions, and reduced fuel consumption, this study investigates the optimizing effect of the synergistic action between oxyhydrogen negative pressure inhalation (ONPI) and lean-burn on the combustion of a bio-isopropanol/gasoline dual-fuel combined injection engine. The experiments were conducted under the conditions of a speed of 1500 r/min, a manifold absolute pressure (MAP) of 42 kPa, and a bio-isopropanol direct injection ratio (BIDIr) of 40 %, with the experimental variables being different excess air ratios (lambda = 1 similar to 1.4) and oxyhydrogen negative pressure inhalation volumes (ONPIv = 0-16 L/min). The results show that ONPI significantly improves engine power performance; under lambda = 1.4, the IMEP at ONPIv = 16 L/min is 6.37 % higher than that at 0 L/min. It also reduces emissions (under lambda = 1.4, the HC emissions at ONPIv = 16 L/min are 33.81 % lower than those at 0 L/min) and cyclic variation (the CoVIMEP under optimal conditions is reduced by 29.76 % compared with the original engine), and the effect intensifies with the increase of lambda. CO emissions are greatly affected by lean-burn; under lambda = 1.1, CO emissions are reduced by an average of 90.4 % compared with those under lambda = 1. Lean-burn can effectively suppress NO emissions. In addition, oxyhydrogen and lean-burn can synergistically improve indicated thermal efficiency, which reaches the highest value at lambda = 1.4 and ONPIv = 12 L/min, being 2.82 % higher than that of the original engine.

Orientated-type gas flow channels are beneficial for the enhancement of Proton Exchange Membrane Fuel Cells (PEMFC) performance; however, higher flow losses are incurred as well. In this study, the flow characteristicss of the orientated gas flow channel are studied numerically; and the geometries of baffles are optimized using a Genetic Algorithm to minimize their flow losses. The results show that as the middle baffle length (L1) increases, the high-velocity zone expands, which leads to higher friction losses and pressure drops. Moreover, increasing the sloped leeward side baffle length (L2) reduces the vortices size on the leeward side, and increasing the inclination angle of the leeward side can mitigate the boundary layer separation and vortices formation. For lower baffle heights (R = H/4 and R = H/2), an increase in the mid-section length leads to a significant reduction in flow losses, indicated by pressure drop. However, for high baffle heights (R = 3H/4), the optimal L2 is insensitive to the variation of L1, indicating that the baffle height for high baffles dominates the flow resistance of channels. The pressure drop between the inlet and outlet of the optimized channel can be reduced by 4.8 % compared to that of the original geometry.

To reduce the consumption of gasoline, improve thermal efficiency and promote the cyclic development of internal combustion engine technology, this paper utilizes the jet ignition technology and uses hydrogen as fuel in the active pre-combustion chamber to achieve ultra lean-burn of gasoline under lambda of 2.1. On this basis, influence of various pre-combustion chamber hydrogen injection timing (HIT), pre-combustion chamber hydrogen injection pressures (HIP) and their corresponding ignition timings (IT) on the engine emission profile are investigated. The findings indicate that the selection of a rational pre-combustion chamber hydrogen injection strategy can effectively reduce the emission of engine pollutants and improve the combustion economy. For HC and CO, IT of 15 degrees CA BTDC is optimal. By adjusting the injection strategy on this basis, both HC and CO emissions are minimized at HIP of 3 MPa with HIT of 140 degrees CA BTDC, decreasing by 49.26% and 54.75%, respectively. A favorable combustion atmosphere will inevitably lead to higher NOx emissions, and a smaller IT is required to achieve lower NOx emissions. The injection strategy and IT mainly affect particle number concentration with diameter less than 30 nm, so the effect on NPN emissions is very significant, while the effect on APN is insignificant. Meanwhile, the particulate emissions in general decrease with the advancement of IT. A relatively low HIP and a relatively late HIT can result in the best BSFC and brake thermal efficiency. "HIP of 3 MPa,HIT of 160 degrees CA BTDC and IT of 14 degrees CA BTDC" is considered to be the best control strategy.

Due to the imperfect fuel characteristics, the specific fuel consumption of ethanol fuel was larger than that of gasoline, which limited the application of ethanol fuel in the engine field. H2O2 is a strong activity additive to regulate fuel properties. In this paper, the Converge simulation platform was used to study the effects of H2O2 additive on temperature field distribution and micro-active radicals of an SI combined injection engine fueled by ethanol/gasoline under the stratification and homogeneous combustion. The research results showed that the H2O2 additive could effectively promote flame core formation and development and have a more significant effect on the stratification combustion. Considering the whole power stroke, the combustion of the homogeneous mixture was more complete, the active groups were more, the heat loss was less, and the output power of the engine was greater. In general, 20% H2O2 additive plus DIT = 300°CA BTDC could contribute to the power and ultra-low emissions of the engine.

Hairpin motors were widely regarded for high slot fill rate, low DC resistance short, and end length compared to round-wire motors. Radial oil spray cooling can be implemented by opening holes in the motor casing or setting oil rings. Also, this cooling method can take away surface heat from the end windings of the motor by directly cooling them, effectively improving the motor power density. However, the radial oil spray cooling for hairpin motors end winding was less studied. This paper investigated the radial oil spray cooling characteristics of different numbers and types of nozzles under different flow rates. The results showed that cooling performance increased with increasing flow rates. The cooling uniformity increased with the increasing number of nozzles, but the increase in cooling uniformity decreased when the nozzles arrangement angle exceeded 180°. Full cone and fan nozzles both had a better cooling effect than column nozzles. When the nozzle spraying angle was smaller than the nozzle arrangement spacing angle, the greater the nozzle spraying angle, the better the overall cooling effect. Conversely, the larger the nozzle spraying angle, the worse the overall cooling effect. This study can help engineers implement radial oil spray cooling designs for hairpin motors.

In the face of escalating environmental challenges, curbing gasoline consumption and enhancing engine thermal efficiency have emerged as top priorities. This paper focuses on a gasoline/hydrogen dual-fuel engine equipped with an active pre-combustion chamber. By utilizing hydrogen as the fuel for the active pre-combustion chamber, stable combustion under ultra lean-burn conditions has been successfully achieved. The impact of precombustion chamber hydrogen injection strategy on the engine lean-burn characteristics is investigated. To streamline the experimental process and identify the injection strategy that exerts the most significant influence on each engine combustion parameter, the orthogonalization method is adopted. Results show that engine combustion is significantly affected by the intensity of jet flame. Hydrogen injection timing determines the hydrogen concentration in the pre-combustion chamber during ignition, thus having the greatest impact on engine combustion. Due to the limited volume of the pre-combustion chamber in jet-ignition engines, the influence of hydrogen injection pressure is not obvious. Meanwhile, ignition timing determines the matching relationship between the combustion process and the combustion phase. "HIP of 3 MPa, HIT of 160 degrees CA BTDC and IT of 15 degrees CA BTDC" is the best injection control strategy.

The thermal management of a driving motor is related to the performance and economy of the vehicle. The lumped-parameter thermal network (LPTN) method can provide a model basis for motor temperature-rise control and effectively shorten the development cycle of motor thermal performance design. In this study, an 80 kw water-cooled permanent magnet synchronous motor was used and the accurate thermal model of a motor was built using the LPTN. On the basis of the accurate thermal model, the simplified thermal model of a motor was obtained by reducing the complexity of the model. The temperature-rise test of the end winding and magnetic steel of the motor was carried out under some working conditions. The test conditions were selected according to continuous external characteristics and operating characteristics of the motor. Compared with the experimental results, the temperature-rise error of the two thermal models was less than 5%. The temperature-rise error of the simplified thermal model was less than 3% compared with the accurate thermal model. Therefore, the simplified thermal model can be used to quickly predict the temperature rise of the motor.

The combination of renewable energy and multifuel combined supply is an efficient way to deal with the energetic crisis and the pollution of environment. Ethanol, gasoline and oxyhydrogen participate in combustion by means of three independent supply paths, which can improve engine power and reduce gasoline consumption and gaseous pollutant emission at the same time. However, the optimization of ternary-fuel combined supply mode is a problem that must be clarified. In this study, the engine performance at four direct injection pressure (DIP), six direct injection timing (DIT), five intake manifold absolute pressures (MAP) and four speeds is studied under the condition of equal ethanol injection ratio and gasoline injection ratio. The experimental results show that ethanol direct injection forms a mixture with a better stratified combustion state than gasoline direct injection. Moreover, oxyhydrogen negatory pressure inhalation (ONPI) can effectually increase Pmax and IMEP, reduce APmax, CA 10-90, CA 0-10, CO emission, HC emission and particulate emission, but increase NOx emission. However, ethanol direct injection (EDI) can reduce NOx emission produced by ONPI, and oxyhydrogen can attenuate the negatory effect on mixture combustion due to the excessive latent heat of vaporization of ethanol. NO emission in EDI mode is reduced by an average of 28.39 % compared to gasoline direct injection (GDI) mode under different MAPs. In conclusion, the combustion and emission characteristics of the engine in EDI + gasoline port injection (GPI) + ONPI mode are better than those in ethanol port injection (EPI) + GDI + ONPI mode. And the control strategy of "9-11 MPa DIP+250-300 degrees CA BTDC DIT +16 L/min oxyhydrogen negative pressure inhalation volume (ONPIv)" can improve the performance of EDI + GPI + ONPI engine while reducing emission.

After-treatment device diesel oxidation catalyst (DOC) and selective catalytic reduction (SCR) were installed in the exhaust system of ammonia/diesel dual-fuel engine to remove harmful pollutants such as hydrocarbon (HC), carbon monoxide (CO), ammonia (NH3), nitrogen oxide (NOx), nitrous oxide (N2O) and other pollutants produced by the dual-fuel combustion mode. The results indicate that the HC, CO and N2O emissions of ammonia/diesel dual-fuel engine increase with the increment of ammonia fraction, whereas NOx emissions decrease. At 50 % load, the CO conversion efficiency of DOC decreases from 100 % at diesel-only mode to 18.9 % at 40 % ammonia fraction, while the HC conversion efficiency is independent of ammonia fraction. NOx can be reduced by NH3 in the exhaust, while NH3 will be oxidized to N2O and NOx in DOC. Moreover, at 50 % load, more NH3 emission is oxidized to N2O compared to 75 % load. After SCR, the NOx, N2O and NH3 emissions in the exhaust are further reduced, but due to the NH3/NOx ratio, there are still a large amount of NOx and NH3 emissions at SCR outlet. The N2O conversion efficiency of SCR is relatively low, with a maximum value of only 47.8 % at 50 % load and 30 % ammonia fraction. Owing to the high N2O emission from dual-fuel engine, the direct introduction of ammonia cannot significantly reduce greenhouse gas (GHG) emissions. Furthermore, the massive amount of unburnt ammonia in the exhaust is oxidized to N2O by DOC, leading to a sharp increase in GHG emissions after DOC + SCR aftertreatment, and the GHG emissions at 50 % load and 40 % ammonia fraction are 6.2 times higher than those before the aftertreatment, and 9.2 times higher than those of diesel-only mode.

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The Direct Injection (DI) of Compressed Natural Gas (CNG) in a CNG/gasoline dual fuel engine had the advantages of suppressing the knock tendency and expanding the lean burn limit of Spark Ignition (SI) engines without loosing their volumetric efficiency. However, the effects of CNG Direct Injection Timing (DIT) and Spark Timing (ST) on the performances of engines were rarely reported, despite their significant importance on the formation of stratified fuel mixture. Thus, the performance, combustion and emissions characteristics of CNG/gasoline combined injection SI engines under different combinations of CNG DIT and ST were experimentally studied. The results showed that the optimal CNG DIT and ST yielded higher torque, lower Brake Specific Fuel Consumption (BSFC), larger Effective Thermal Efficiency (ETE) and less Particle Numbers (PN) emissions compared with those of non-optimal combinations. The variation of ST dominated the change of engine performance under different CNG DIT and ST combinations. For a specific CNG DIT, advancing ST resulted in higher in-cylinder pressure and Heat Release Rate (HRR), earlier combustion phase, and shorter flame propagation duration; however, the flame development duration became longer and HC, NOx emissions were larger for earlier STs. The majority of the PN emissions of CNG/gasoline engines with CNG DI was in the Nucleation Mode (NM); and the particle size followed an unimodal nucleation distribution pattern peaking around 15 nm.

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Ethanol was a viable alternative and renewable fuel for spark ignition engines, and ethanol/gasoline dual-fuel combustion with combined injection strategy can strengthen the benefits of using ethanol in engines. However, delicate calibration and optimization were required for ethanol/gasoline DFSI engines due to their higher control complexity and flexibility. Therefore, Artificial Neural Network (ANN) models were developed to represent the performance of DFSI engines. This study established the architecture for the ANN models of ethanol/gasoline DFSI engines, and the topology of 8-36-24-3, 8-64-70-6, 8-48-48-3, and 8-36-16-2 were suggested for the modeling of performance, combustion characteristics, gaseous and PN emissions, respectively. The non-linear relationship between the core control variables and performance, combustion, and emission characteristics of ethanol/gasoline engines can be accurately mapped by the proposed ANN models. The regression values were within the range of 0.9387–0.9962, and the mean square relative errors were within the range of 0.000184–0.03935 between the ANN predicted and experimentally measured results. Moreover, the ANN models had the advantages of high accuracy, sound model completeness, superior robustness, and satisfied reliability, which were desirable for the calibration and optimization of engines.

Hydrous ethanol is a green fuel with great potential to deal with crises in the environment and energy. The study on the ethanol life cycle showed hydrous ethanol with 10%-20% water content had the best benefit, but the water content >10% would deteriorate engine power and emission performance. In this paper, the effects of the 30 vol% laboratory-grade H2O2 on the combustion performance and emission characteristics were explored in an ethanol/gasoline combined injection engine. At the engine operating condition of engine speed/manifold air pressure = 1500 rpm/49.5 kPa, the H2O2-ethanol blend direct injection (DI) and gasoline port injection were conducted. Results showed that H2O2 greatly improved the operating performance of the hydrous ethanol/gasoline engine. As the 30 vol%-H2O2 ratio in the H2O2-ethanol blend (H(2)O(2)r) increased, the P-max and the T-max first increased and then decreased. Both CA0-10 and CA10-90 were slightly extended. For the DI ratio = 10%-40%, the optimal IMEP was obtained at H(2)O(2)r = 15%, which was 0.09 bar-0.11 bar higher than H(2)O(2)r = 0%. The optimal BTE was 0.86%, 0.75%, 0.71% and 0.75% higher than H(2)O(2)r = 0%, respectively. As the H(2)O(2)r and DI ratio increased, HC and NOx emissions descended, and CO emissions decreased first and then ascended slightly with the critical H(2)O(2)r = 10%-15%. Optimal CO, HC and NOx emissions were 21.76%, 58.83% and 42.02% lower than gasoline, respectively. H2O2 could reduce particulate emissions, while the H(2)O(2)r < 15% at the DI ratio = 30%-40% should be adopted.