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With its advantages on cost and performance, the integrated exhaust manifold (casting with the turbine) is being used on more vehicles by auto makers. Generally, when compared with the divided exhaust manifold, the integrated exhaust manifold stands for higher vibratory excitation from gas dynamics. In this paper, the gas dynamics excitation has been computed through the GD (gas dynamics) software GT-Power which calculates the exhaust pipe surface pressure, and CFD code Star-CCM+ which calculates the turbine blade force. And the response of manifold has been solved under this excitation. On the other hand, the mechanical excitation has been computed through the MBD (multi-body dynamics) platform AVL-Excite-PU, and the responses under the gas excitation plus the mechanical load have been studied in order to analyze the effects of the fluid excitation on an integrated manifold.

In order to provide an improved countermeasure for occupant protection, a new type of active reversible preload seatbelt (ARPS) is presented in this paper. The ARPS is capable of protecting occupants by reducing injuries during frontal collisions. ARPS retracts seatbelt webbing by activating an electric motor attached to the seatbelt retractor. FCW (Forward Collision Warning) and LDW (Lane Departure Warning) provide signals as a trigger to activate the electric motor to retract the seatbelt webbing, thus making the occupant restraint system work more effectively in a crash. It also helps reduce occupant’s forward movement during impact process via braking. Four important factors such as preload force, preload velocity and the length and timing of webbing retraction play influential roles in performance of the ARPS. This paper focuses on studying preload performance of ARPS under various test conditions to investigate effects of the aforementioned factors.

A 3D grid model of engine brake is established for an automobile engine. The dynamic compression release braking process is simulated by using this model. In the process of engine braking, the movement of valve and piston causes changes of the internal flow field of the engine. In this paper, the movement of valve and piston were defined by using the dynamic grid technology, so that the numerical simulation is closer to the actual situation via the updating of grid. Based on the relevant parameters of compression release engine brake (including the opening of the exhaust valve, the engine speed and the exhaust back pressure), the pressure and power of the compression release braking system were simulated under the conditions of multiple operating conditions and experimental verification was carried out. The results showed that the braking works of the compression release engine brake are mainly from the compression stroke and the exhaust stroke.

Uncertainties present a large concern in actual vehicle motion and have a large effect on vehicle system control. We attempt a new robust control design approach for braking/driving force distribution and active front steering of vehicle system with uncertain parameters. The braking/driving force distribution control is equivalently studied as the integral direct yaw moment control. Then the control design is carried out by using a state-space vehicle model with embedded fuzzy uncertainties. By taking the compensated front wheel steering angle and the direct yaw moment as the control inputs, a feedback control that aims to compensate the system uncertainty is proposed. In a quite different angle, we employ fuzzy descriptions of the uncertain parameters. The controlled system performance is deterministic, and the control is not if-then rules-based. Fuzzy descriptions of the uncertain parameters are used to find an optimal control gain.

Hydraulic retarder, as an auxiliary braking device, is widely used in commercial vehicles. Nowadays, the hydraulic retarder’s internal oil is mainly cooled by the coolant circuit directly. It not only aggravates the load of engine cooling system, but also makes the abundant heat energy not be recycled properly. In this study, an independent energy supply device with organic Rankine cycles is applied to solve the problems above. In the structure of this energy supply device, the evaporator’s inlet and outlet is connected in parallel with the oil outlet and inlet of the retarder respectively. A part of oil enters the evaporator to transfer heat with the organic fluid, and the rest of oil enters the oil-water heat exchanger to be cooled by the coolant circuit. According to the different braking conditions of the retarder, the oil temperature in the inlet of the hydraulic retarder can be kept within the proper range through adjusting the oil flow rate into the evaporator properly.

Natural gas is a promising alternative fuel for internal combustion engines due to its rich reserves and low price, as well as good physical and chemical properties. Its low carbon structure and high octane number are beneficial for CO2 reduction and knock mitigation, respectively. Diesel and natural gas dual fuel combustion is a viable pathway to utilize natural gas in diesel engines. To achieve high efficiency and low emission combustion in a practical diesel engine over a wide range of operating conditions, understanding the performance responses to engine system parameter variations is needed. The controllability of two combustion strategies, diesel pilot ignition (DPI) and single injection reactivity controlled compression ignition (RCCI), were evaluated using the multi-dimension CFD simulation in this paper.

This work presents a comprehensive computational study of diesel - natural gas (NG) dual fuel engine. A complete computational model is developed for the operation of a diesel - NG dual fuel engine modified from an AVL 5402 single cylinder diesel test engine. The model is based on the KIVA-3V program and includes customized sub-models. The model is validated against test cell measurements of both pure diesel and dual fuel operation. The effects of NG on ignition and combustion in dual fuel operation are analyzed in detail. Zero-dimensional computations with a diesel surrogate reaction mechanism are conducted to discover the effects of NG on ignition and combustion and to reveal the fundamental chemical mechanisms behind such effects. Backed by the detailed theoretical analysis, the engine operation parameters are optimized with genetic algorithm (GA) for the dual fuel operation of the modified AVL 5402 test engine.

A multidimensional numerical simulation method was developed to analyze air/fuel premixing, stratified combustion and NOx emission formation in a gasoline direct injection (GDI) engine. Firstly, many submodels were integrated into one Computational Fluid Dynamics (CFD) code: ICFD-CN, such as Sarre nozzle flow, Kelvin-Helmholtz (KH) dynamic jet model, Taylor-Analogy Breakup (TAB) model, Rayleigh-Taylor (RT) droplet breakup model, Lefebvre fuel vaporization model, Liu droplet drag & distortion model, Gosman turbulence & droplet dispersion model, O'rourke wall film model, O'rourke and Bracco droplet impinging & coalescence model, Stanton spray/wall impinging model, the Discrete Particle Ignition Kernel(DPIK)ignition model, the single step combustion and the patulous Zeldovich model for NOx generation mechanism. The integrated CFD code was then calibrated against experimental data in a gasoline direct injection engine for several engine operating conditions.

In this paper, a passive anti-pitch anti-roll hydraulically interconnected suspension is proposed for compromising the control between the pitch and roll mode of the sprung mass. It has the advantage in improving the directional stability and handling quality of vehicles during steering and braking manoeuvres. Frequency domain analysis of a 7-DOF full-car model with the proposed system is presented. The modeling of mechanical subsystem is established based on the Newton's second law. Then the mechanical-hydraulic system boundary conditions are developed by incorporating the hydraulic strut forces into the mechanical subsystem as externally applied forces. The hydraulic subsystem is modelled by using the impedance method, and each circuit are determined by the transfer matrix method. And then the modal analysis method is employed to perform the vibration analysis between the vehicle with the conventional suspension and the proposed HIS.

To meet more stringent emission regulations for diesel engines, diesel particulate filters (DPF) have been widely used for diesel engines. However, the DPF regeneration is a great challenge for fuel economy. In this paper, a mathematical model characterizing the microwave regeneration process of a wall-flow particulate filter is introduced to better understand the process. Based on this model, important parameters such as evolutions of the energy stream densities of microwaves, wall temperature, regeneration efficiency and the pressure drop in the filters, both cordierite and SiC, are investigated. These results can provide an important theoretical guide for optimizing and controlling the microwave regeneration process.

In this paper, a new roll-plane hydraulically interconnected suspension (HIS) system is proposed to enhance the roll and lateral dynamics of a two-axle bus. It is well-known that the suspension tuning is of great importance in the design process and has also been explored in a number of studies, while only minimal efforts have been made for suspension tuning for the newly proposed HIS system especially considering lateral stability. This study aims to explore lateral dynamics and suspension tuning of a two-axle bus with HIS system, which could also provide valuable information for roll dynamics analysis. Based on a ten-DOFs lumped-mass full-car model of a bus either integrating transient mechanical-hydraulic model for HIS or the traditional suspension components, three newly promoted parameters of HIS system are defined and analyzed-namely the total roll stiffness (TRS), roll stiffness distribution ratio (RSDR) and roll-plane damping (RPD).

Hybrid electric vehicles (HEVs) are considered as the most commercial prospects new energy vehicles. Most HEVs have adopted Atkinson cycle engine as the main drive power. Atkinson cycle engine uses late intake valve closing (LIVC) to reduce pumping losses and compression work in part load operation. It can transform more heat energy to mechanical energy, improve engine thermal efficiency and decrease fuel consumption. In this paper, the investigations of Atkinson cycle converted from conventional Otto cycle gasoline engine have been carried out. First of all, high geometry compression ratio (CR) has been optimized through piston redesign from 10.5 to 13 in order to overcome the intrinsic drawback of Atkinson cycle in that combustion performance deteriorates due to the decline in the effective CR. Then, both intake and exhaust cam profile have been redesigned to meet the requirements of Atkinson cycle engine.

This paper introduces a vehicle model in CarSim, and replaces a portion of its standard suspension system with an HIS model built in an external software to implement co-simulations. The maneuver we employ to characterize the HIS vehicle is a constant radius method, i.e. observing the vehicle’s steering wheel angle by fixing its cornering radius and gradually increasing its longitudinal speed. The principles of the influence of HIS systems on cornering mainly focus on two factors: lateral load transfer and roll steer effect. The concept of the front lateral load transfer occupancy ratio (FLTOR) is proposed to evaluate the proportions of lateral load transfer at front and rear axles. The relationship between toe and suspension compression is dismissed firstly to demonstrate the effects of lateral load transfer and then introduced to illustrate the effects of roll motion on cornering.

The driving risk field model offers a feasible approach for assessing driving risks and planning safe trajectory in complex traffic scenarios. However, the conventional risk field fails to account for the vehicle size and acceleration, results in the same trajectories are generated when facing different vehicle types and unable to make safe decisions in emergency situations. Therefore, this paper firstly introduces the acceleration and vehicle size of surrounding vehicles for improving the driving risk model. Then, an integrated decision-making and planning model is proposed based on the combination of the novelty risk field and model predictive control (MPC), in which driving risk and vehicle dynamics constraints are taken into consideration. Finally, the multiple driving scenarios are designed and analyzed for validate the proposed model.

This paper presents the different influence factors to vehicle's path planning, including the guide-potential shape and its parameters, the guild-potential influence scale factor, the stiffness of the elastic bands and the speed of the host vehicle. The assessment of emergency path is based on the dynamic performance of the host vehicle, the lateral acceleration and yaw rate, and its mean-square values accesses the stability of the host vehicle when following the path. In order to take evasion maneuvers more steadily, a guide-potential affecting the moving vehicles behind the obstacle is built, which encourages the host vehicle to change lane appropriately. Three different shape guide-potential models, namely half-circle-like, half-ellipse-like and parabola-like, are proposed and compared in this paper. Meanwhile, hazard map of the road environment which includes the lanes, borders and obstacles is generated.

Due to its load control strategy via fresh charge quantity, pumping loss in a homogenous charge gasoline engine is a significant contributor to the high fuel consumption rate at light load. Exhaust gas recirculation (EGR) and lean burn technologies are the common means to reduce gasoline engine pumping loss for fuel economy improvement. Many previous publications compared the EGR and lean burn concepts. However, few of those were able to compare the EGR and lean burn concepts under the same in-cylinder dilution basis. Usually the un-swept in-cylinder residual gas fraction (RGF), which can be significant at very low loads, was ignored due to lack of appropriate method to determine it. Also the theoretical potential and practical limitations were rarely discussed. In this paper, a Naturally Aspirated (NA) gasoline engine was systematically tested for both the EGR and lean mixture concepts on an engine dyno. under the same speed and load conditions.

Air spring due to its superior ride comfort performance has been widely used in distance passenger transporting vehicles. Since the requirements for ride comfort and handling performance are contradict to each other, handling performance and even roll stability are sacrificed to some extent to obtain good ride comfort. Due to the complex terrain and limited manufacturing level, in the past several years, bus rollover accidents with serious casualties have been reported frequently and bus safety has attracted more and more attention from bus manufacturers in China. On one hand the bus standards have to be raised, and on the other hand, novel solutions which can effectively improve the roll stability of air spring bus are needed to replace the inadequacy of anti-roll bars.

Electromagnetic suspension systems have increasingly gained widespread attention due to their superiority in improving ride comfort while providing fast response, excellent controllability and high mechanical efficiency, but their applications are limited due to the accuracy of the underlying control actuation tracking. For addressing this problem, this study presents a novel hierarchical control strategy for an electromagnetic active suspension (EMAS) system equipped with an electromagnetic actuator (EMA) structure. The structure of the EMA device and the working principle of the motion conversion model are introduced in detail first, and the motion conversion equation is derived based on the force-torque relationship. Based on this, a linear quadratic regulator (LQR) control method is proposed to be applied to a half-vehicle suspension system to improve the vibration isolation performance of the vehicle and ensure the ride comfort.

This paper employs the motion-mode energy method (MEM) to investigate the effects of a roll-plane hydraulically interconnected suspension (HIS) system on vehicle body-wheel motion-mode energy distribution. A roll-plane HIS system can directly provide stiffness and damping to vehicle roll motion-mode, in addition to spring and shock absorbers in each wheel station. A four degree-of-freedom (DOF) roll-plane half-car model is employed for this study, which contains four body-wheel motion-modes, including body bounce mode, body roll mode, wheel bounce mode and wheel roll mode. For a half-car model, its dynamic energy contained in the relative motions between its body and wheels is a sum of the energy of these four motion-modes. Numerical examples and full-car experiments are used to illustrate the concept of the effects of HIS on motion-mode energy distribution.

A multi-step acetone-butanol-ethanol (ABE) phenomenological soot model was proposed and implemented into KIVA-3V Release 2 code. Experiments were conducted in an optical constant volume combustion chamber to investigate the combustion and soot emission characteristics under the conditions of 1000 K initial temperature with various oxygen concentrations (21%, 16%, 11%). Multi-dimensional computational fluid dynamics (CFD) simulations were conducted in conjunction under the same operation conditions. The predicted soot mass traces showed good agreement with experimental data. As ambient oxygen decreased from 21% to 11%, ignition delay retarded and the distribution of temperature became more homogenous. Compared to 21% ambient oxygen, the peak value of total soot mass at 16% oxygen concentration was higher due to the suppressed soot oxidation mechanism.