Search

Battery management systems (BMSs) are essential in ensuring the safe and stable operation of lithium-ion batteries (LIBs) in electric vehicles (EVs). Accurate sensor signals, particularly voltage, current, and temperature sensor signals, are essential for a BMS to perform functions such as state estimation, balance control, and fault diagnosis. The smooth operation of a BMS depends primarily on sensor signals, which provide current, voltage, and temperature information to maintain the battery pack in a safe running state. However, sensor failures and inaccurate measurement data can easily occur because of external interference and complex operating conditions. Therefore, an investigation into the fault diagnosis of battery sensors and fault-tolerant control (FTC) is necessary to ensure the normal operation of a BMS. This paper analyzes the modes of sensor faults, fault diagnosis methods, and fault-tolerant control techniques. First, the different modes of sensor faults are analyzed, and mathematical expressions for these faults are provided. Second, diagnostic methods for sensor faults based on models, signal processing, and data-driven methods are analyzed in detail. Finally, FTC techniques are introduced to ensure stable sensor operation. Based on an analysis of the research status of sensor fault diagnosis, a new development direction for sensor fault diagnosis is proposed.

Abstract This study investigated how structural parameters (including injection ducts and exhaust nozzle inner diameters) affect the internal flow field and dilution ratio of diesel particulate sampling diluters. Increasing air injection duct diameter increased the injection chamber pressure and decreased the air velocity peak, mixed gas flow velocity, sample temperature, and mixing rate. Excessively small tube diameters caused uneven and discontinuous flow field distributions, while substantial air blockage rendered the flow state poor. Increasing nozzle inner diameters increased the exhaust flow area and the sample temperature, but decreased the velocity of the exhaust and gas mixtures and the pressure drop. Compared with a 2.0 mm inner diameter, 2.5 and 3.0 mm diameters decreased the peak velocity by 11.18% and 14.41%, respectively, and mixing slowed significantly. Inner nozzle diameters of

Energy shortage and environmental pollution are becoming more serious, biodiesel is regarded as the most promising alternative fuel for diesel engines due to its environmentally friendly and renewable characteristics. In this study, the biodiesel-ethanol blends were used in a diesel engine, and the purpose of the study was to simultaneously control the NOx and soot emissions of the diesel engine by adjusting the injection strategy and EGR rate. A turbocharged, six-cylinder, common rail direct injection (CRDI) engine model was established using GT-Power. The effects of the main-post injection strategy and post injection coupled with exhaust gas recirculation (EGR) on combustion and emission characteristics were investigated at a maximum torque speed and a medium load. The results show that when the main-post injection strategy is employed, the combustion duration of the main injection is shortened with an increase in the main-post injection interval (MPI). When the MPI increased to more than 18 °CA, the heat release of post injection could be observed clearly from the curve of the heat release rate, NOx emissions decreased by 5.70% and 7.12%, respectively, and soot emissions decreased by 25.56% and 30.20%, respectively. Moreover, with the increasing post injection quantity, the combustion duration of the main injection shortened, and the peak heat release rate (PHRR) of the post injection increased. When the fuel quantity for the post injection increased from 2 to 6 mg, NOx emissions decreased from 2.33% to 9.80%, and soot emissions decreased from 16.10% to 34.97%. The effect of post injection quantity on emissions was more significant than that of the MPI. In addition, with increasing EGR rate, the ignition delay is prolonged, the peak cylinder pressure, PHRR, peak combustion temperature and NOx emissions decrease, whereas soot emissions increase gradually. Main-post injection can improve the NOx-soot trade-off, the optimal EGR rate is 22.86% under a post injection quantity of 4 mg and a MPI of 22 °CA.

Abstract Dilution sampling systems are crucial for obtaining accurate measurements of engine exhaust particulate mass and number. The system design requires a comprehensive understanding of the impact of dilution parameters on its internal flow field and dilution ratio. In this study, a computational fluid dynamics (CFD) model of an ejector diluter was established. This CFD model was validated based on results of experiments conducted on a diesel engine with the self‐designed partial flow sampling system. The discrepancies between the simulation and experimental results of the dilution ratio were acceptable (average error of 7.42% and a minimum error of 0.72%). These errors indicated that the model was suitable for performing numerical simulations. The effects of the dilution parameters, including exhaust gas velocity, exhaust gas temperature, and air velocity, on the internal flow field and dilution ratio of the diluter system were investigated. The results showed that an increase in the exhaust velocity from 0.542 to 1.489 m/s decreased the dilution ratio from 41.31 to 15.98 when the air velocity and pressure were constant at 9.147 m/s and 200 kPa, respectively. A 100 K increase in exhaust temperature increased the dilution ratio by 1.62 on average. When the air velocity was increased from 4.333 to 28.405 m/s, the dilution ratio significantly increased from 10.55 to 64.66 when the exhaust velocity and pressure were constant at 1.083 m/s and 90 kPa, respectively.

IntroductionEnvironmental information disclosure is an important means to protect the ecological environment, and global climate change puts forward higher requirements for corporate environmental information disclosure. New energy companies play an important role in addressing climate change and environmental information disclosure, and should strengthen environmental information disclosure and actively participate in ecological environmental protection.MethodsThis paper selected Chinese new energy listed companies as the research sample to investigate the impact of green credit on corporate environmental information disclosure, and proposed and empirically tested the hypothesis on the mechanism of the effect of green credit on environmental information disclosure.ResultsThe regression results indicated that green credit can effectively improve the quality of corporate environmental information disclosure, and this conclusion is still significantly valid after robustness test; The impact mechanism tests showed that green credit can change the level of corporate environmental information disclosure by controlling company size. This paper also tested the heterogeneity and adjustment effects, showing that the relationship between green credit and environmental information disclosure are affected by multiple factors.DiscussionsCombining the research of this paper and previous research results, it is found that the positive impact of green credit on corporate environmental information disclosure has been confirmed by academic research and practical verification. However, the implementation effect of green credit policy will be affected by the economic level, regional differences, and the comprehensive impact from companies, financial institutions and government departments.

Biodiesel is a promising alternative fuel for diesel engines, but its high viscosity and low volatility have limitations in decreasing emissions. As a renewable alternative fuel with a high oxygen content, ethanol blended with biodiesel can decrease kinematic viscosity and improve fuel evaporation. In this study, the effects of the ethanol addition ratio on the spray, combustion, and emission performances of a diesel engine fuelled with biodiesel were investigated. The spray characteristics were measured using a high-speed camera and Malvern laser analysis, whereas the combustion and emission performances were tested on a turbocharged common rail direct injection (CRDI) diesel engine. The results show that adding ethanol to biodiesel enlarges the spray cone angle (SCA) and shortens spray tip penetration (STP). In addition, the curves of the size–volume distribution (SVD) of the atomized fuel droplets move toward a smaller diameter, and the Sauter mean diameter (SMD) of the biodiesel–ethanol (BE) blends gradually decreases with increasing ethanol proportion. At low loads, the fuel injection strategy is multi-injection, and the peak cylinder pressures (PCPs) of BE blends are 0.77–1.96% higher than that of diesel at different ethanol blending ratios. However, the peak heat release rates (PHRRs) of BE blends are 9.3–11.5% higher than that of diesel owing to a faster combustion rate, longer main-injection duration, and more hydroxyl radicals generated in the pilot-injection stage. At medium–high loads, the injection strategy changes to single injection, the PCPs of BE blends are roughly equivalent to that of diesel, and the PHRRs of BE blends for different ethanol blending ratios are 9.76–11.91% lower than that of diesel. This is because of the lower diffusion combustion ratio, lower heat value, and change of injection duration corresponding to the variation in fuel properties. In addition, the results of the peak pressure rise rate and the cyclic variation indicate that the higher ethanol addition ratio increases the combustion noise and decreases the combustion stability. In terms of exhaust emissions, compared with biodiesel, with increasing ethanol blending ratio, the soot emissions for different BE blends decrease by 11.28–47.23%, the NOx emissions increase by 2.68–7.04%, and the HC emissions increase by 9.99–21.47%. Considering the engine performance comprehensively, a 20% ethanol blending ratio in biodiesel is recommended.

Biofuels have extensive available resources and have an immense potential as promising alternative fuels for automobile. The application advantages of biofuels are mainly reflected as particulate matter (PM) reduction, carbon neutral, greenhouse gases reduction, waste utilization, energy and economic security, and fuel pluralism. Based on the understanding of molecular structure effects of biofuels on soot formation and particles morphology, the effects of alcohols, ethers, esters and biodiesel on spray and combustion process in constant volume bomb in recent years are retrospectively analyzed in this paper. For the mixture, macromolecular ester fuels and polyoxymethylene dimethyl ether (PODE) are conducive to the improvement of liquid spray, while biodiesel, small molecules, dimethyl ether (DME) and alcohols are reversed. Alcohols are advantageous to the extension of mixing time and the increasing of vapor-phase mixture. Through the influence integrated assessment, alcohols show the best performance on the spray, atomization and combustion, while biodiesels show the worst. But in terms of combustion, PODE is the best choice without considering spray and atomization. For binary alternative-diesel fuel blends, methanol or butanol is the best additive based on synthetically considerations on spray, atomization and combustion. To meet the requirements of the fuel application of diesel engine, ternary fuel or even quaternary fuel have been proposed and explored. This review can help to form a systematic understanding on fuel recombining and obtain the guide of clean and efficient fuel formulation for diesel engine.

The purpose of this study was to analyze the influence of the injection pressure and orifice diameter on the spray characteristics of soybean biodiesel. The macroscopic spray characteristics of the spray tip penetration (STP) and spray cone angle (SCA) were tested with a high-speed camera system. The microscopic spray characteristics, such as the statistical size distribution, Sauter mean diameter (SMD), representative diameters and dispersion boundary, were obtained using a Malvern laser particle size analyzer (PSA). The test results showed that with an increasing injection pressure, the STP and the SCA of the biodiesel increased, but the curves of size-volume distribution and cumulative volume distribution of the atomized droplets shifted to smaller diameters. The SMD and representative diameters decreased, and the dispersion boundary was reduced. Moreover, with a decreasing orifice diameter, longer STP and smaller SCA values were observed. Similarly, the size distribution curves of the atomized biodiesel droplets shifted to smaller diameters. The SMD and representative diameters were reduced, and the relative size range of the atomized biodiesel droplets was enlarged. Higher injection pressures and smaller orifice diameters improved the biodiesel atomization; however, the smaller orifice diameters caused an inhomogeneous size distribution of the atomized biodiesel droplets.

Abstract The purpose of this study is to investigate the effects of fuel temperature and nozzle length‐diameter ratio (L/D) on biodiesel spray characteristics, under high injection pressure and high ambient pressure, by numerical method. The analysis of spray characteristics is carried out in conjunction with the transient flow inside nozzle. To achieve this, three‐dimensional calculation grids of spray nozzle and spray domain were setup, and the needle movement was achieved by dynamic mesh technique. The reliability of spray models was validated by experimental results. It was established that the variation in spray tip penetration (STP) and Sauter mean diameter (SMD) is similar at different initial conditions. The STP increases at a faster rate initially and then slows down, whereas the SMD gradually decreases with time after the injection. In addition, a sensitivity analysis of the effects of injection parameters on biodiesel spray characteristics was conducted. Compared to the nozzle L/D, injection pressure and fuel temperature have a greater impact on biodiesel spray characteristics. The increase in injection pressure has a significant effect on the velocity distribution, STP and SMD. When the injection pressure is increased from 100 to 200 MPa, the maximum velocity of the spray core zone increases by 33.96%, the STP increases by 27.17%, and the SMD reduces by 14.81%. Furthermore, an increase in fuel temperature mainly affects the concentration distribution and the SMD of atomized droplets. When the fuel temperature is increased from 300 to 350 K, the maximum concentration of axial spray center lowers by 25.41%, and the SMD decreases by 17.19%. However, the increase of L/D chiefly impacts the concentration of axial spray center, but has little effect on other spray parameters. When the nozzle L/D is increased from 4 to 8, the maximum concentration of axial spray center increases by 20.29%.