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High speed on-off valves (HSVs) are widely used in advanced hydraulic braking actuators, including regenerative braking systems and active safety systems, which take crucial part in improving the energy efficiency and safety performance of vehicles. As a component involving multiple physical fields, the HSV is affected by the interaction of the fields-fluid, electromagnetic, and mechanical. Since the opening of the HSV is small and the flow speed is high, cavitation and vortex are inevitably brought out so that increase the valve’s noise and instability. However, it is costly and complex to observe the flow status by visual fluid experiments. Hence, in this article a visual multi-physics system simulation model of the HSV is explored, in which the flow field model of the HSV built by computational fluid dynamic (CFD) is co-simulated with the model of hydraulic actuator established by AMESim.

During the engaging process of sleeve and teeth ring in mechanical transmissions, their rotational speed and position differences cause multiple engaging ways and trajectories, and casual impacts between them will delay the engaging process and cause a long power off time for a gear shift. In order to reveal the engaging mechanism of the sleeve and the teeth ring, it is essential to build a high-fidelity model to cover all of their engaging ways and capture their speed changes for an impact. In this work, our contribution is that their impact process is modeled as a precise, continuous and nonlinear damping model, and then a hybrid automaton model is built to connect the system dynamics in different mechanical coupling relationships.

At first, the dynamic electromagnetic characteristics of a pulsed solenoid valve is analyzed by experiments. The fast valve response is obtained by material modifications. Then, the intelligent solenoid driving method is discussed. The new techniques of the “active” PWM and the “d2i/dt2” detection are developed for feedback control of the solenoid holding current and the valve closure timing. Finally, the control and diagnosis method for the valve closure duration is investigated. A sensing mechanism utilizing momentary camshaft speed fluctuations of fuel injection pump is presented, which provides the basis for feedback control and diagnosis of the valve closure duration and diesel fuel injection process.

Atomization of fuel sprays is a key factor in controlling the combustion quality in the direct-injection engines. In this present work, the effect of saturation ratio (Rs) on the near nozzle spray patterns of ethanol was investigated using an ultra-high speed imaging technique. The Rs range covered both flash-boiling and non-flash boiling regions. Ethanol was injected from a single-hole injector into an optically accessible constant volume chamber at a fixed injection pressure of 40 MPa with different fuel temperatures and back pressures. High-speed imaging was performed using an ultrahigh speed camera (1 million fps) coupled with a long-distance microscope. Under non-flash boiling conditions, the effect of Rs on fuel development was small but observable. Clear fuel collision can be observed at Rs=1.5 and 1.0. Under the flash boiling conditions, near-nozzle spray patterns were significant different from the non-flash boiling ones.

Ground impact caused by road debris can result in very severe fire accident of Electric Vehicles (EV). In order to study the ground impact accidents, a Finite Element model of the battery pack structure is carefully set up according to the practical designs of EVs. Based on this model, the sequence of the deformation process is studied, and the contribution of each component is clarified. Subsequently, four designs, including three enhanced shield plates and one enhanced housing box, are investigated. Results show that the BRAS (Blast Resistant Adaptive Sandwich) shield plate is the most effective structure to decrease the deformation of the battery cells. Compared with the baseline case, which adopts a 6.35-mm-thick aluminum sheet as the shield plate, the BRAS can reduce the shortening of cells by more than 50%. Another type of sandwich structure, the NavTruss, can also improve the safety of battery pack, but not as effectively as the BRAS.

Engine torque fluctuation is a great threat to vehicle comfort and durability. Former researches tried to solve this problem by introducing active damping system, which means the motor is controlled to produce torque ripple with just the opposite phase to that of the engine. By this means, the torque fluctuation produced by the motor and the engine can be reduced. In this paper, a new method is raised. An attempt is proposed by changing the traditional structure of the motor, making it produce ripple torque by itself instead of controlling the motor. In this way a special used ISG (Integrated Starter Generator) motor for HEV (Hybrid Electrical Vehicles) is made to achieve active damping. In order to study the possibility, a simulation, which focus on the motor instead of the whole system, is developed and series-parallel configuration is used in this simulation. As for the motor that used in this paper, four kinds of motors have been investigated and compared.

Advanced exhaust after-treatment technology is required for heavy-duty diesel vehicles to achieve stringent Euro VI emission standards. Diesel particulate filter (DPF) is the most efficient system that is used to trap the particulate matter (PM), and particulate number (PN) emissions form diesel engines. The after-treatment system used in this study is catalyzed DPF (CDPF) downstream of diesel oxidation catalyst (DOC) with secondary fuel injection. Additional fuel is injected upstream of DOC to enhance exothermal heat which is needed to raise the CDPF temperature during the active regeneration process. The objective of this research is to numerically investigate soot loading and active regeneration of a CDPF on a heavy-duty diesel engine. In order to improve the active regeneration performance of CDPF, several factors are investigated in the study such as the effect of catalytic in filter wall, soot distribution form along filter wall, and soot loads.

Batteries have various sizes and can be configured into different layouts in battery pack on electric vehicles. Crash safety performance is one of the key requirements in choosing battery geometric characteristics and designing layout of battery cells in battery pack. In this study, we compared impact responses of different configurations and geometric characteristics of battery cells under side pole impact. The side pole impact is a relatively dangerous collision type for electric vehicles, often causing large deformation and damage to the battery. Using a production battery pack, we first conducted side pole impact tests with sled tester, and then simulated the test configuration.

In order to realize the series-parallel switching control of hybrid electric vehicle (HEV) with dual-motor hybrid configuration, a method of unpowered interrupt switching based on the coordinated control of three power sources was proposed by analyzing the series-parallel driving mode of the dual-motor hybrid configuration. The series to parallel switching process is divided into three stages: speed regulation stage, clutch combination and power source switching. The distribution control of speed regulating torque is carried out in the speed regulating stage. The speed adjustment torque is preferentially allocated to the power source of the input shaft (engine and P1) to carry out the lifting torque. Due to the high speed adjustment accuracy and fast response of the P1 motor, the input shaft is preferentially allocated to P1 for speed adjustment, that is, the torque intervention of P1.

In order to achieve seamless mode switching control for hybrid electric vehicles (HEVs) in the event of battery failure, we propose a motor voltage-controlled mode switching method that eliminates power interruptions. This approach is based on an analysis of the dual-motor hybrid configuration's mode switching. We analyze the overall vehicle operation when the high-voltage battery occurs in different hybrid modes. To ensure that the vehicle can still function like a conventional car under such circumstances, we introduce a novel "voltage control" mode. In this mode, instead of operating in its traditional torque control manner, the P1 motor adopts a voltage control strategy. The P1 controller's variable becomes "voltage," and VCU sends the motor's working mode switching request and PCM finishes the mode transition. During system operation, the P1 motor promptly responds to these target voltages to maintain bus voltage within a normal range.

A vehicle dynamics stability control system based on integrated-electro-hydraulic brake (I-EHB) system with hierarchical control architecture and nonlinear control method is designed to improve the vehicle dynamics stability under extreme conditions in this paper. The I-EHB system is a novel brake-by-wire system, and is suitable to the development demands of intelligent vehicle technology and new energy vehicle technology. Four inlet valves and four outlet valves are added to the layout of a conventional four-channel hydraulic control unit. A permanent-magnet synchronous motor (PMSM) provides a stabilized high-pressure source in the master cylinder, and the four-channel hydraulic control unit ensures that the pressures in each wheel cylinder can be modulated separately at a high precision. Besides, the functions of Anti-lock Braking System, Traction Control System and Regenerative Braking System, Autonomous Emergency Braking can be integrated in this brake-by-wire system.

The mechanical behavior of polyvinyl butyral (PVB) film plays an important role in windshield crashworthiness and pedestrian protection and should be depth study. In this article, the uniaxial tension tests of PVB film at various strain rates (0.001 s-1, 0.01 s-1, 0.1 s-1, 1 s-1) and temperatures (-10°C, 0°C, 10°C, 23°C, 40°C, 55°C, 70°C) are conducted to investigate its mechanical behavior. Then, temperature and strain rate dependent viscoelastic characteristics of PVB are systematically studied. The results show that PVB is a kind of temperature and strain rate sensitive thermal viscoelastic material. Temperature increase and strain rate decrease have the same influence on mechanical properties of PVB. Besides, the mechanical characteristics of PVB change non-linearly with temperature and strain rate. Finally, two thermal viscoelastic constitutive model (ZWT model and DSGZ model) are suggested to describe the tension behavior of PVB film at various strain rates and temperatures.

This paper analyzes the current control, mode control and boost strategy of permanent magnet synchronous motor in dual hybrid system, which has good stability and robustness. Current control includes current vector control, MTPA control, flux weakening control, PI current control and SVPWM control. Motor mode includes initialization mode, normal mode, fault mode, active discharge mode, power off mode, battery heating mode and boost mode. The boost strategy of the hybrid system is based on boost mode management, boost target voltage determination and boost PI control. The specific content is as follows: Boost mode control. Boost mode includes initial mode, normal mode, off mode and fault mode. Boost target voltage is determined. Boost converter is controlled by variable voltage, which depends on the operation status of the motor and generator..

In order to reduce driver's anxiety about range and energy, a direct and effective approach is to offer the remaining driving range based on the vehicle's states. Consequently, the estimation accuracy of the battery's remaining energy is very important. This paper introduces a experiment-based model for predicting the remaining energy, which considers many factors, such as current, temperature, difference between battery cells, and so on. This approach ensures the accuracy of the remaining driving range. Finally the method is validated through the environment space test. Validation results show that this method can offer exact remaining energy, which reduces the estimation error of the remaining range greatly.

Due to the objectives of achieving high fuel efficiency and drivability performance, a dual-drive hybrid system with two motors has been developed. Various drive modes are presented based on engine status, requested driver torque and power, as well as C0 status in different working conditions. The transition control of drive mode change poses a unique challenge for the dual-drive hybrid system. This study discusses the control strategies for transitioning between drive modes. The first type of transition mode is divided into four distinct phases. In the second mode transition, there are three phases: the synchronization phase involving P1 torque intervention, the C0 lock-up phase involving frozen P1 torque control and adjustment of C0 clutch torque and pressure correlation, and finally, the torque exchange phase. The third type of transition includes a dedicated torque transition phase followed by a C0 disengaged phase and concluding with a speed synchronization phase.

To tackle the over-actuated and highly nonlinear characteristics that four-wheel-independent-steering and four-wheel-independent -driving (4WIS/4WID) vehicles exhibit when tracking aggressive trajectory, a hierarchical controller with layers of computation-intensive modules is commonly adopted. The high-level linear motion controller commands the desired state derivatives of the vehicle to meet the overall trajectory tracking objectives. Then the system dynamic is inversed by the mid-level control allocation layer and the low-level wheel control layer to map the target state derivatives to steering angle and motor torque commands. However, this type of controller is difficult to implement on the embedded hardware onboard since the nonlinear dynamic inversion is typically solved by nonlinear programming.

Electric vehicles maintain the fastest development in China and undertake the responsibility of optimizing energy consumption and carbon emission in the transportation field. However, from the entire life cycle point of view, although electric vehicles have a certain degree of energy consumption and carbon emission reduction in the use phase, they cause extra energy consumption and carbon emission in the manufacturing phase, which weakens the due environmental benefits to some extent. The recycling of electric vehicles can effectively address the issue and indirectly reduce the energy consumption and carbon emission in the manufacturing phase. China is setting up the recycling system and strengthening regulation force to achieve proper energy consumption and carbon emission reduction benefits of electric vehicles. Under the current electric vehicle recycling technologies, China can reduce about 34% of carbon emission in electric vehicle manufacturing phase.

Electric vehicle (EV) is a worldwide researching focus due to its environmental friendliness, but the inaccurate Remaining Driving Range (RDR) estimation hinders the EVs' popularity, and an accurate determination of the battery Residual Usable Energy (RUE) is the key factor to obtain a precise RDR value. A common RUE estimation method is based on State-of-Charge (SOC) estimation, in which the RUE is proportionally related to the current SOC. However, the battery voltage varies significantly under real-world conditions, and the traditional method results in certain estimation errors. An adaptive RUE prediction method (AEP) is introduced in this paper, in which the dynamic voltage is predicted based on the future discharge profile and a battery model, while the RUE is then calculated by the predicted voltage and current sequences.

A conventional vehicle with gasoline engine was tested on a chassis dynamometer over the new European drive-cycle (NEDC). The distributions of the engine speed and power, the throttle positions during the drive cycle are analyzed. Engine idling, acceleration and deceleration take an important proportion in the drive cycle. If engine idling is instead by engine stop, the fuel consumption will be improved by 2.27%. In an Integrated Starter Generator (ISG) system, with the assist of the starter/generator, transient operation of the engine will decrease, which reduces fuel consumption by 6%. Fuel economy will be also improved by braking regeneration and restricting operating points to an optimized region, the details are not discussed in this paper. To reduce fuel consumption further, the region where engine usually runs in urban traffic, should be paid more attention to while engine calibration.

To characterize emission performance and engine operating conditions during high-power cold starts (HPCS), a blended plug-in hybrid electric vehicle was tested over worldwide harmonized light-duty vehicle test cycle (WLTC), and a new cycle was developed to characterize HPCS. The results showed that the engine speed and load increased dramatically to high level during HPCS under the low temperature of coolant and catalysts. The higher concentration of particle number (PN) and NOx at higher speed and load, accounted for the higher emissions during HPCS. Besides, the cumulative PN emissions increased first and then decreased with the increasing coolant temperature.