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Subzero startup constitutes a lingering obstacle impeding the diffusion of battery and fuel cell electric vehicles in cold regions. Both being electrochemical energy devices, lithium-ion battery (LIB) and polymer electrolyte fuel cell (PEFC) share many commonalities in their cold startup problems, tasks and principle behind startup techniques. Subzero startup of LIB and PEFC using alternating current (AC) is receiving increasing attention for its high efficiency, low degradation and superb reliability. To catch the wider attention in the research community and promote the development of this technique, we herein address the AC startup of LIB and PEFC in a single review and in a same framework. After a brief introduction to low temperature performance problem, subzero startup techniques for LIB and PEFC are classified based on a new criterion, i.e. the nature of the heat generation, instead of the location of heat generation. Then, the principle, development and implementation of AC startup are outlined. For the startup of LIB, the Li deposition criterion, the validation and variations in battery, and the comparison with the direct current techniques are elaborated. For the startup of PEFC, the validation in cell, the extension to stack, and the comparison with the air restriction self-heating technique are elaborated. Finally, the common challenges and special requirements for starting up LIB and PEFC are discussed, and the remaining issues and directions for further research are highlighted.

Alternating current preheating (ACP) of lithium-ion batteries has the advantage of a high heating rate while inhibiting lithium plating. Two strategies based on terminal voltage control and full battery impedance control were proposed to simplify the ACP implementation. However, such strategies either severely compromise the preheating rate or induce non-negligible lithium plating. To maximize the preheating rate while ensuring no lithium plating, an ACP method based on anode potential control is developed using a square wave alternating current. The operation boundaries of lithium plating prevention, in terms of frequency and maximum permissible current amplitude, are determined using the anode potential and impedance. Their effectiveness in preventing lithium plating is validated by repeating 800 cycles of preheating. By applying the operation boundaries, a temperature-adaptive preheating is found to be able to speed up the preheating rate with higher frequency, smaller temperature intervals and better thermal insulation. When the battery is preheated at a frequency of 400 Hz, with a temperature interval of 5 °C and a heat transfer coefficient of 5 Wm−2 K−1, the preheating rate can reach 6.61 °C/min, exceeding the method based on the terminal voltage control by 5.4%, and larger than that based on the full battery impedance control strategy by 41.8%.

The high NO2/NOX ratio in the after-treatment system is beneficial to its performance and achieved by NO catalytic conversion in diesel oxidation catalyst (DOC) located upstream (CRDPF), catalytic DPF (CDPF), or a combination of both (CCDPF). In order to effectively control the emission of particulates and nitrogen oxides, various types of diesel particulate filter models are established to compare NO2 catalytic formation, consumption, and efflux. The results show that the catalytic performance of NO conversion is limited by mass transfer in DOC catalytic coating, while it is almost non-existent in CDPF. At low temperature, the passive regeneration of CDPF is slower than that of CRDPF, but as the temperature increases, the passive regeneration speed of CDPF will exceed that of CRDPF. CCDPF is the most effective for the NO2 catalytic formation, consumption, and efflux in the hot-start and high-speed cycle and thereby is conducive to improve the performance of the diesel particulate filter and downstream selective catalytic reduction.

A model is established to investigate low temperature ( 550 °C) performance of the continuous regenerative diesel particulate filter (CR-DPF) assisted by electric regeneration regarding to balance point temperature, regeneration speed and outlet temperature respectively and relevant influencing factors. Results show that inlet PM concentration and inlet flow rate are positively correlated to balance point temperature and vice versa for initial soot loading and intake NO X concentration. Increasing intake NO X concentration and flow rate increase rapid continuous regeneration speed. At low and medium temperatures, rapid thermal response tends to increase passive regeneration speed and the trend is more with decreasing wall thickness and channel density. In the high temperature range, outlet temperature increases and temperature gradients presented in the early stage of regeneration become steeper with decreasing channel density and wall thickness. However, “L/D” has limited impact on low, medium and high temperature performance.

A model describing NH3 selective catalytic reduction (NH3-SCR) over Cu-ZSM-5 to investigate the effects of intraphase and interphase mass transfer on standard SCR reaction is developed and further verified with the synthetic gas bench. The correlation between tortuosity and porosity has been analyzed by least squares method and applied to the sinuousoidal capillary bundle model. The effects of washcoat thicknesses, lengths, cell densities and channel widths on the standard SCR reaction are analyzed in temperature range of 150–500 °C. It is found that deNOx efficiency is affected by intraphase diffusion limitations at 200–500 °C and by interphase mass transfer limitation at intermediate (250–400 °C) and high temperatures (400–500 °C). As the temperature increases, the reaction is firstly controlled by kinetics, with the kinetics resistance decreasing and then increasing until the maximum among three processes. Furthermore, intake flow rates (GHSVs) play an important role impacting NO conversion on NH3–SCR.

It is very important for the diesel engine to achieve a cold startup at low environmental temperature especially in the region with the temperature in the range of −40 °C to 0 °C. Thus, the specific cold start characteristics, such as gas leakage, heat loss and clearance volume, should be investigated in detail. In order to investigate the cold start ability, an improved thermodynamic model for thermodynamic parameters is developed. The prediction of ignition temperature is the closest to the experimental values when the adiabatic index is equal to 1.34 for the compressed gas. The thermodynamic results show that the compression pressure is the most sensitive to the gas leakage rate, followed by the heat transfer loss rate and reference clearance volume. The gas leakage, heat loss and clearance volume are employed to investigate the cold start ability for the diesel engine, which provide a better reference for strengthening the cold start capacity research. The small clearance volume and big initial intake air temperature can improve the exergy of diesel engine. In addition, the entropy production increases with the increase of clearance volume. Similarly, the exergy of system will reduce with the increase of entropy production. Finally, the improvement suggestions for cold starting performance enhancement of the diesel engine are proposed.

Parabolic dish solar concentrators are currently one of the most efficient solar technologies for the production of electricity. These systems are usually located in an open terrain where strong winds may be found and could affect their stability and optical performance. Mirror gap size has direct relation to thermal efficiency and construction cost. A tiny deformation of the concentrator under the action of a strong wind affects the focusing accuracy and increases the requirement of the structural strength of the dish. In this paper, different gap sizes (0–60 mm) between the mirrors of the dish are studied by numerical simulation. The results show that wind load on concentrator is sensitive to operation position, such as 30° pitch and 60° yaw angle. The gap causes an uneven distribution of the mean pressure coefficient on each facet, thereby increasing the risk of wind-induced vibration at the mirror edge. Besides, the drag coefficient on a parabolic dish increases along with the increase of the gap size between 0 and 60 mm when the dish is at the wind-resistant unfavorable conditions. For the overall wind force on a dish in the state of maximum drag force operation angle case, the mirror gap can reduce the wind force by about 3.54% with the gap size increased, which is mainly due to the significant reduction of the windward area. Therefore, the mirror gap should take as small a size as possible.

The gasification kinetic characteristics of food waste (FW) gasification by supercritical water (SCW) were investigated by examining the SCW gasification (SCWG) of FW in a quartz tube reactor, and the experimental results were investigated by using a series of kinetic models. The experimental results show that the carbon gasification efficiency increases with reaction temperature at the same residence time, and reactivity increases sharply at the early stage of gasification and then decreases with reaction time. The simulation results show that all the classical kinetic models underestimate the experimental results, similar to the models used in previous work on coal gasification by SCW. The underestimation of the models results from the catalytic effect of alkaline earth metals (AAEMs), which can notably increase the active sites of gasification reaction without changing the gasification kinetic mechanism. To solve the above problem, the catalytical effect to describe the kinetic behavior of the SCWG of FW is considered and a semiempirical modified random pore model (MRPM) is developed based on the RPM model. The simulation results of the MRP models are close to experimental findings, indicating that MRP model can be used to predict the entire process of SCWG under different conditions without dividing gasification into different stages of reaction. The MRP model can also be used for the prediction of SCWG of coal, biomass, and organic wastes and is crucial to reactor optimization and scaling up.

In this work, the low water-level water-biodiesel emulsion (WBE) fuels (2, 4 and 6 wt%) and pure biodiesel fuel were used to investigate the effects of water addition on spray, combustion and emission characteristics of a medium speed diesel engine in terms of cylinder pressure, cylinder temperature, heat release rate, brake power, brake thermal efficiency, brake specific fuel consumption, NOx, soot, CO and CO2 emissions. The corresponding three-dimensional CFD model was performed by AVL-Fire coupled CHEMKIN II code, and an improved chemical kinetics mechanism containing 475 reactions and 134 species was developed to simulate the fuel spray process and combustion process since it contained methyl linolenate, methyl linoleate, methyl oleate, methyl stearate, methyl palmitate, a majority component in most biodiesel, thus improved the accuracy of simulation. The result obtained showed that the water addition in fuel played an important role in fuel spray process and fuel combustion process. The fuel-air mixing was improved due to the micro-explosion. More specifically, the findings revealed that low-level water addition in biodiesel fuel could reduce NOx, CO and CO2 emissions. The optimal water addition level in terms of diesel engine emission and performance parameters was found at 4 wt% among WBE fuels. In particular, the NOx, CO and CO2 emissions were reduced respectively, at maximum speed of 1000 rpm. Thus, the relationship between water addition rate and combustion and emission characteristics is not straightforward, the balance between water addition and fuel is very important.

The high NO

Miniaturization of gasoline engines equipped with turbochargers is an effective way to alleviate energy shortages and reduce emissions, whereas its compressor noise has become an issue. In order to research the effects of particular blade tip clearance and blade number on noise reduction of high-speed (100,500 rpm) centrifugal compressor used for gasoline engine under actual working conditions, the aerodynamic noise of a turbocharger compressor mounted on a passenger car engine is analyzed by using turbulence numerical simulation, aero-acoustic simulation and acoustic boundary element method (BEM). On the basis of the transient large eddy simulation calculation of the compressor flow field, the aero-acoustic analogy noise model and the acoustic boundary element method are used to calculate the aerodynamic noise of the compressor. The frequency spectrum of compressor BPF noise is analyzed, and the influence of different blade tip clearances and blade numbers on the broadband noise and BPF noise of the compressor at high speed is studied. The research of compressor related structural parameters on aerodynamic noise plays an important role in reducing compressor noise and improving compressor acoustic quality.

In order to effectively investigate the effects of various factors on the DPF's performance deterioration, and obtain the primary influence factor, an efficient evaluation method is proposed in this work. Firstly, the maximum wall temperature and the pressure drop are taken as the evaluation indexes of DPF's performance deterioration (thermal aging and filter clogging) respectively, and the orthogonal experimental design is used for obtaining the simulation conditions of test cases. Then, the impacts of four structural factors (wall thickness, mean pore size, porosity and channel width) and five operating factors (exhaust flow rate, exhaust oxygen concentration, microwave power, catalytic additive mass concentration and deposited ash mass) on DPF's performance deterioration are evaluated by fuzzy membership grades and Euclidean grey relational grades, respectively. Finally, fuzzy grey relational analysis is employed to make a comprehensive evaluation. The results show that the wall thickness and the channel width have the most noticeable effect on filter clogging and thermal aging among all structural factors, respectively. Moreover, the deposited ash mass and the microwave power are the most important operating factors for filter clogging and thermal aging, respectively. This work offers us great reference value for optimizing DPF performances and improving its degradation resistance.

The comparative analysis on combustion, performance and emissions characteristics of a PFI SI engine fueled with methanol, ethanol and butanol-gasoline blends under various alcohol ratio, equivalence ratio and engine load was carried out. The combustion phasing was advanced after adding alcohols due to the higher burning velocity, which also resulted in BTE decreasing as the engine was running at gasoline’s MBT. Therefore, the sparking timing should be postponed when fueled with alcohols-gasoline blends. The butanol-gasoline blends showed the lower BSFC for its higher LHV. There was no uniform CO emission trend after adding alcohols based on the competing between the increased oxygen content, reduced combustion temperature and combustion duration, compared to gasoline. However, UHC emission was increased for methanol-gasoline blends as a more injected fuel and a sequent more fuel getting into the crevice volumes or absorbed in oil layers and deposited, while decreased for ethanol and butanol-gasoline blends due to the fuel-borne oxygen improving combustion quality. Meanwhile, based on the reduced combustion temperature resulting from more products generated in terms of heat capacity of combustion products for the alcohols, alcohols-gasoline blends presented the lower NOx emission. Ethanol and methanol-gasoline blends produced the lowest UHC and NOx emissions respectively.

A washcoat resolved numerical model of catalytic micro combustor fueled by methane is developed. Detailed gas phase mechanism and alumina dioxide supported Pt-based surface mechanism are adopted. This model proves to capture flow, temperature and species fields precisely including impermeable flow and products accumulation in porous washcoat layer. The novelty and superiority of this research compared to traditional modeling method in which instantaneous diffusion onto catalytic wall is assumed lies in that: it is possible to investigate effects of porous washcoat properties with this full-scale numerical model. Computational results show that homogeneous reactions (HR) are impaired and heterogeneous reactions (HTR) are strengthened as channel confinement increases. Da number analysis reveals that the micro combustor works under a mixed controlled mode in which catalytic reaction rate and internal mass diffusion rate are comparable. When washcoat layer thickness increases from 15 μm to 75 μm, overall catalyst usage roughly decreases from 0.34 to 0.05. It is concluded washcoat thickness can’t be too thin in order to maintain HTR intensity and too thick since catalyst usage is extremely low. Porous washcoat properties impact combustion characteristics in a similar mechanism: modifying effective mass diffusion coefficient. In general, increasing porosity, average pore diameter and decreasing tortuosity will enhance HTR and impair HR. In real application, these parameters can be utilized to modify combustion temperature, emission performance and stability operation map.

In our previous works, the diesel particulate filter (DPF) using a new composite regeneration mode by coupling microwave and ceria-manganese base catalysts is verified as an effective way to reduce the particulate matter emission of the diesel engine. In order to improve the overall performance of this DPF, its multidisciplinary design optimization (MDO) model is established based on objective functions such as pressure drop, regeneration performance, microwave energy consumption, and thermal shock resistance. Then, the DPF is optimized by using MDO method based on adaptive mutative scale chaos optimization algorithm. The optimization results show that with the help of MDO, DPF’s pressure drop is decreased by 14.5%, regeneration efficiency is increased by 17.3%, microwave energy consumption is decreased by 17.6%, and thermal deformation is decreased by 25.3%. The optimization results are also verified by experiments, and the experimental results indicate that the optimized DPF has larger filtration efficiency, better emission performance and regeneration performance, smaller pressure drop, lower wall temperature and temperature gradient, and lower microwave energy consumption.

A new developed four-component biodiesel combustion skeletal mechanism comprising methyl decenoate, methyl-5-decenoate, n -decane and methyl linoleate is presented in this work, which could predict soot formation trends with varying fatty acid methyl esters proportion. It was established based on a detailed n -heptane mechanism, HACA-mechanism and our previously developed four-component biodiesel combustion skeletal mechanism without soot formation mechanism. This new developed mechanism consists of 134 species and 475 reactions. In order to validate the feasibility of this new skeletal mechanism, ignition delay testing, constant volume combustion chamber experiment testing and diesel engine experiment testing were performed. The result indicates that it is suitable to predict ignition behavior, flame lift-off length, soot shape and distribution, cylinder pressures, heat release rate and NO x emission trends of biodiesel with varying fatty acid methyl esters proportion.

Numerical simulation has been carried out to investigate the major factors affecting the time of composite regeneration due to coupling cerium-based additive and microwave for diesel particulate f3ilter (DPF). Effect on the composite regeneration time from various factors such as mass flow rate of exhaust gas, temperature of exhaust gas, oxygen concentration of exhaust gas, microwave power and amount of cerium-based additive are investigated. And a mathematical model based on fuzzy least squares support vector machines has been developed to forecast the endpoint of the composite regeneration. The results show that the relative error of endpoint forecasting model of composite regeneration is less than 3.5%, and the oxygen concentration of exhaust gas has the biggest effect on the endpoint of composite regeneration, followed by the mass flow rate of exhaust gas, the microwave power, the temperature of exhaust gas and the amount of cerium-based additive.

Based on the characteristics of ash cake deposition, the single channel model and the packed bed model, a mathematical model of filtration process of wall-flow filter for ash deposition in cake has been proposed. The effects of the amount of ash load and the distribution of ash deposition in cake on the filtration characteristic of filter are analyzed. Results show that the filtration efficiency improves rapidly with the increase of ash load while ash layer proportion is nonzero. When ash layer proportion is zero (i.e. ash plug proportion is 100%), the filtration efficiency decreases with the increase of ash load. Otherwise, the filtration efficiency improves with the increase of ash layer proportion while the ash load is constant. Considering the effects of ash on both filtration efficiency and flow resistance, the active regeneration system is more helpful to balance the correlation between filtration efficiency and flow resistance for ash tends to build up at the end of the channels in active system. The experimental results have verified the accuracy of mathematical model.

Non-combustible ash can be deposited on channel walls through the full length of a diesel particulate filter (DPF). This type of ash can affect the exhaust condition and heat transfer process during the periodical soot regeneration of DPF. A model of soot regeneration is established in this paper to describe the effects of ash deposits on exhaust condition and heat transfer. Mass, momentum, and energy balances are considered for the multiphase system of gas, soot, and wall. The good agreement with experimental data confirms that the model is able to describe the processes. The axial patterns of wall temperature and soot regeneration rate during DPF regeneration are investigated by numerical simulation. Results indicate that the deposited ash layer reduces the exhaust flow rate and increases the heat conduction resistance during DPF regeneration, thus leading to high wall temperature and soot oxidation rate. When 5 g/L of ash is deposited, the complete oxidation of soot can be achieved 90 s faster with a 60 ∘C increase in wall temperature. The gain on soot oxidation rate increases with increasing amounts of deposited ash and reaches a plateau when the deposited ash approaches 15 g/L. Owing to the sintering and melting of ash when the temperature reaches 900 ∘C and the consequent uncontrolled regeneration, the soot carrying capacity should be identified based on the amount of deposited ash within DPF.

Based on models A, B, and C of three kinds of diesel particulate filter (DPF) with microwave regeneration, a DPF microwave regeneration model is established according to the laws of conservation of mass, momentum, and energy. The trends of internal temperature under different velocities of exhaust gas in channels are simulated and analyzed. The results show that: (1) Regeneration temperature in the process of microwave regeneration will begin to increase from the front to the rear end of along the axial direction, and the maximum temperature value will appear in the rear end of the monolith. (2) The internal flow velocity in the DPF of model C is the most uniform and the temperature gradient is the smallest among the three models. Therefore, it is the most useful for DPF regeneration. (3) The minimal thermal stress is exerted on the DPF of model C. Therefore, this model is most useful for prolonging the service life of a DPF.

Taking wall-flow diesel particulate filter (DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of steady filtration for wall-flow diesel particulate filter were developed and verified by experiments as well as numerically solved. Furthermore, the effects of the macroand micro-structural parameters of filtering wall and exhaust-flow characteristic parameters on trapping efficiency were also analyzed and researched. The results show that: 1) The two developed mathematical models are consistent with the prediction of variation of particulate size; the influence of various factors on the steady trapping efficiency is exactly the same. Compared to model 2, model 1 is more suitable for describing the steady filtration process of wall-flow diesel particulate filter; 2)The major influencing factors on steady trapping efficiency of wall-flow diesel particulate filter are the macro-and micro-structural parameters of filtering wall; and the secondary influencing factors are the exhaust-flow characteristic parameters and macro-structural parameters of filter; 3)The steady trapping efficiency will be improved by increasing filter body volume, pore density as well as wall thickness and by decreasing exhaust-flow, but effects will be weakened when particulate size exceeds a certain critical value; 4) The steady trapping efficiency will be significantly improved by increasing exhaust-flow temperature and filtering wall thickness, but effects will be also weakened when particulate size exceeds a certain critical value; 5) The steady trapping efficiency will approximately linearly increase with reducing porosity, micropore aperture and pore width.

In order to reveal the mechanics of composite regeneration by coupling cerium-based additive and microwave for a diesel particulate filter, a composite regeneration model by coupling cerium-based additive and microwave for a diesel particulate filter was established based on field synergy theory. Performance evaluation on field synergy and composite regeneration of the diesel particulate filter was conducted by using the vortex crushing combustion and field synergy mathematical models. The results show that the peak temperature of the particulate filter body reaches 1180–1190 K when the regeneration time is 175 s, and there are optimal coordination degree between the velocity vector and temperature gradient of the filter body and the maximum ratio 0.56–0.60 of the best burning regeneration region is obtained. Accordingly, the largest regeneration combustion rate inside the particulate filter body and the highest regeneration efficiency at the moment are achieved.

Combining a detailed catalytic surface reaction mechanism with noble metal and promoter elementary reactions, a new three-way catalytic converter (TWC) reaction mechanism is established. Based on the new mechanism, steady condition numerical simulation is carried out, and the change of light-off temperatures and conversion efficiency with various SO2 contents is obtained. By grey relational analysis (GRA), the relational grade between conversion efficiency and SO2 content is obtained. And, the result shows that SO2 content has the most important influence on C3H6 and NOX conversion efficiency. This provides an important reference to the improvement of activity design of TWC, and may provide guidance for the condition design and optimization of TWC.

In order to solve fretting instability problem of gear shaft shoulder due to torsional vibration in mechanical system, the mathematical model of fretting instability vibration of gear shaft shoulder was established by adopting the method of combining kinematics and tribology, and the numerical analysis was applied to the fretting instability mechanism of gear shaft shoulder by introducing the friction instability damping ratio. The numerical results show that the main factors causing the unstable and vibrating gear shaft shoulder are the large tightening torque and too large static friction coefficient. The reasonable values of the static friction coefficient, the amount of interference and tightening torque can effectively mitigate the fretting instability phenomenon of gear shaft shoulder. The experimental results verify that damping plays a significant role in eliminating the vibration of gear shaft control system.

In order to enhance the precision of prediction on composite regeneration time of diesel particulate filter for vehicle, different predictive values of each prediction model are selected as the primeval input values of functional link neural network, and the functional link neural network prediction model of composite regeneration time based on fuzzy adaptive variable weight algorithm is established after the necessary and sufficient conditions for fitting of functional link neural network are analyzed. The application result of the model shows that the absolute value |emax| of maximum relative error of functional link neural network prediction model on composite regeneration time of diesel particulate filter for vehicle based on fuzzy adaptive variable weight algorithm is less than 0.86%, indicating the high accuracy of the prediction model. Moreover, the result draws that the factors influencing composite regeneration time prediction of diesel particulate filter for vehicle, influence degree of which is from big to small, are exhaust oxygen concentration, exhaust mass flow, microwave power, exhaust temperature and the amount of cerium-based additive.

Based on the phenomenon of serious fretting wear of gear shaft shoulder in the process of rotating, the finite element software ABAQUS was used to build the finite element model of the bearing and gear shaft assembly. The interference between the gear shaft and the bearing was considered and the fretting damage at the gear shaft shoulder was analyzed based on the simulation results. The effects of interference on fretting wear of gear shaft shoulder were studied combining with Archard’s wear law. By analyzing the effects of the different interferences on the stresses and displacement amplitudes of gear shaft shoulder, the conclusion can be obtained: the stresses between the bearing inner ring and the shaft shoulder increase with the increase of the interference, on the contrary, the displacement amplitudes between gear shaft shoulder and bearing decrease with the increase of the interference. Therefore, the appropriate interference fitted connections not only guarantee that there is no slip at the mating surfaces, no plastic deformation and failure in the mating parts, but also enable the gear shaft to have the sufficient contact pressure to transmit the effective torque. The finite element method provides an effective approach to analyze the fretting wear of gear shaft shoulder. The fretting wear of gear shaft shoulder can be effectively mitigated if the value of interference is set appropriately.

It is difficult for diesel vehicle battery to meet microwave energy consumption during regeneration of diesel particulate filter, which restricts the application of microwave regeneration technology. In order to minimize the microwave energy consumption during the composite regeneration heating phase of the diesel particulate filter, an optimal microwave energy consumption model is established in this study based on the Functional Analysis Principles. The solution of this optimal model is simulated by the Adaptive Variable Scale Chaos Immune Algorithm. The optimized results are got and verified by experiments under different experimental cases. The simulation results show that an optimal microwave power and regeneration heating time can be effectively obtained during the composite regeneration heating phase. The experimental results indicate that optimization microwave energy consumption under 4 experimental cases decrease by 5.65%, 5.70%, 10.64% and 14.64% compared with that unoptimized data of 93.8 kJ, 75.6 kJ, 65.8 kJ and 56.7 kJ, respectively. The ratio of efficiency to energy of the optimized cases is higher than that of the cases without optimization. The effects of optimal microwave energy consumption in the heating process of composite regeneration are investigated. Moreover, the microwave assisted composite regeneration can save about 24% and 48% energy by contrast of the microwave regeneration and fuel post-injection regeneration. The proposed microwave energy consumption optimization method can save microwave energy and meet the regeneration performance requirement of the diesel particulate filter.

As for the factors affecting the heat transfer performance of complex and nonlinear oscillating heat pipe (OHP), grey relational analysis (GRA) was used to deal with the relationship between heat transfer rate of a looped copper-water OHP and charging ratio, inner diameter, inclination angel, heat input, number of turns, and the main influencing factors were defined. Then, forecasting model was obtained by using main influencing factors (such as charging ratio, interior diameter, and inclination angel) as the inputs of function chain neural network. The results show that the relative average error between the predicted and actual value is 4%, which illustrates that the function chain neural network can be applied to predict the performance of OHP accurately.

A two-dimensional gas–particle two-phase flow model in an inlet channel of diesel particulate filter (DPF) has been developed. The interaction between the gas and the particle is treated as one-way coupling due to the extremely dilute particle concentration. The drag force, the Brownian excitation, and the partial slip are included in the particle motion equation. The particle motion trajectories for various particle source locations and various particle sizes are presented. The dependences of the velocity field of the channel on wall permeability and upstream velocity are evaluated. The effects of particle size, upstream velocity, wall permeability, Brownian motion, and partial slip on the particle deposition are investigated. The three dominant mechanisms, which are drag force, Brownian motion, and particle inertia, are analyzed deeply. These results demonstrate that the drag force always plays the most primary role in determining the particle motion and deposition. On the other hand, the effects of Brownian motion and particle inertia vary with Pe number and Rep* number, respectively. As Pe number and Rep* number increase, the effect of particle inertia enhances, while the effect of Brownian motion lowers. The predicted velocity field is compared with the results obtained from the classical one-dimensional model, and the computational pressure loss of DPF is compared with the experimental values. The reasonable agreements of the two cases are both observed.

Based on results of chaos characteristics comparing one-dimensional iterative chaotic self-map x = sin(2/x) with infinite collapses within the finite region[−1, 1] to some representative iterative chaotic maps with finite collapses (e.g., Logistic map, Tent map, and Chebyshev map), a new adaptive mutative scale chaos optimization algorithm (AMSCOA) is proposed by using the chaos model x = sin(2/x). In the optimization algorithm, in order to ensure its advantage of speed convergence and high precision in the seeking optimization process, some measures are taken: 1) the searching space of optimized variables is reduced continuously due to adaptive mutative scale method and the searching precision is enhanced accordingly; 2) the most circle time is regarded as its control guideline. The calculation examples about three testing functions reveal that the adaptive mutative scale chaos optimization algorithm has both high searching speed and precision.

Based on many experiments of CO 2 laser welding of vehicle body, joint microstructure and stress–strain curve of specimen are analyzed. The deep punching performance acquired by adopting Ar as protective gas is better than that of the one acquired by adopting N 2 as protective gas. Meanwhile the percentage of zinc in welding seam can be effectively controlled by means of blowing side protective gas. In this paper, welding penetration and width are shown to vary with laser power and speed of welding. The results indicate that some flaws such as gas hole, crack and softening of HAZ do not appear in laser welding seam in sheet steel of automobile bodies if technology parameters optimizes. The deep punching performance of tailor-welding sheet is fine.

A mathematical model based on fuzzy least squares support vector machines has been developed to forecast the composite regeneration endpoint of the diesel particulate filter in Vehicle. The results show that the relative error of forecasting model of composite regeneration endpoint is less than 3.5%, and the oxygen concentration of exhaust gas has the biggest effect on the endpoint of composite regeneration, followed by the mass flow rate of exhaust gas, the microwave power, the temperature of exhaust gas and the amount of cerium-based additive.

The energy regenerative braking system (ERBS) of the CFA6470 parallel hybrid electric vehicle (CFA6470PHEV) has been designed using the T-S fuzzy model and fuzzy control toolbox in the MATLAB. The inputs and outputs of the system, along with their membership functions, are reported. The T-S fuzzy model is established for the system and the fuzzy inference system (FIS) is also established. The simulation results indicate that, in the course of driving, the braking torque provided by the electrical motor is controlled in the region that the electrical motor permits, the mechanical braking torque can reach a high value, and the results are consistent with the model.

The hybrid ratio of a parallel hybrid electric vehicle (PHEV) and its energy management strategy are analysed. On the basis of the drivetrain configuration of the CFA6470 parallel hybrid electric vehicle (CFA6470PHEV), the energy management system of the CFA6470PHEV is designed. The optimisation of the engine throttle angle and vehicle shift, along with the mild hybrid and full hybrid strategy are also studied. An energy balance method is introduced to estimate the state of charge for the battery pack. The energy management system is simulated with the experimental data of the engine and ECE-EUDC cycles. Simulation results indicate that the energy management system is feasible and achieve the anticipated goal.