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In this paper, a model-based diagnostic system was developed to detect and isolate the dosing fault and the outlet NOx sensor fault for the SCR system. The dosing fault is treated as an actuator additive fault, while the outlet NOx sensor drift and/or offset fault is treated as a sensor additive fault. First, a 0-D SCR model was developed to facilitate the model-based approach. A parity equation residual generator was designed based on the linearized SCR model and the fault transfer function matrix. The diagnostic algorithm is then implemented in the Matlab/Simulink environment for validation. A high fidelity nonlinear 1-D SCR model is used to generate system outputs and to simulate the plant. The simulation results show that the model-based fault diagnosis system succeeds in detecting and isolating the outlet NOx sensor and dosing faults with good sensitivity and robustness

Vehicle hood styling has significant influence on headform kinematics in assessment tests of pedestrian impact protection performance. Pedestrian headform kinematics on vehicle front-end models with different hood styling characteristics is analyzed based on finite element modeling. More elevated feature lines near hood boundary and the following continuous hood surface towards fender will result in a different headform motion. It can lead to larger deformation space, more rotation and earlier rebound of the headform impactor, which will benefit the head impact protection performance. In addition, hood geometry characteristics such as hood angle and curvature have effects on structural stiffness. Therefore, inclusion of considerations on pedestrian head protection into the vehicle hood styling design stage may lead to a more effective and efficient engineering design process on headform impact analysis.

To provide a feasible transitional solution from all-by-human driving style to fully autonomous driving style, this paper proposed concept and its control algorithm of a robust lane-keeping ‘co-pilot’ system. In this a semi-autonomous system, Learning based Model Predictive Control (LBMPC) theory is employed to improve system's performance in target state tracking accuracy and controller's robustness. Firstly, an approximate LTI model which describes driver-vehicle-road closed-loop system is set up and real system's deviations from the LTI system resulted by uncertainties in the model are regarded as bounded disturbance. The LTI model and bounded disturbances make up a nominal model. Secondly, a time-varying model which is composed of LTI model and an ‘oracle’ component is designed to observe the possible disturbances numerically and it is online updated using Extended Kalman Filter (EKF).

Combustion behaviour and emissions characteristics of different blending ratios of diesel and gasoline fuels (Dieseline) were investigated in a light-duty 4-cylinder compression-ignition (CI) engine operating on partially premixed compression ignition (PPCI) mode. Experiments show that increasing volatility and reducing cetane number of fuels can help promote PPCI and consequently reduce particulate matter (PM) emissions while oxides of nitrogen (NOx) emissions reduction depends on the engine load. Three different blends, 0% (G0), 20% (G20) and 50% (G50) of gasoline mixed with diesel by volume, were studied and results were compared to the diesel-baseline with the same combustion phasing for all experiments. Engine speed was fixed at 1800rpm, while the engine load was varied from 1.38 to 7.85 bar BMEP with the exhaust gas recirculation (EGR) application.

The dynamic properties of disc rotor play important role in the NVH performance of a disc brake system. Disc rotor in general is a centrosymmetric structure. It has many repeated-root modes within the interested frequency range and they may have significant influence on squeal occurrence. A pair of repeated-root modes is in nature one vibration mode. However, in current complex eigenvalue analysis model and relevant analysis methods, repeated-root modes are processed separately. This may lead to contradictory result. This paper presents methods to deal with repeated-root modes in substructure modal composition (SMC) analysis to avoid the contradiction. Through curve-fitting technique, the modal shape coefficients of repeated-root modes are expressed in an identical formula. This formula is used in SMC analysis to obtain an integrated SMC value to represent the total influence of two repeated-root modes.

In this paper, a multi-mode active seat suspension with a single actuator is proposed and built. A one-DOF seat suspension system is modelled based on a quarter car model of commercial vehicle with an actuator which is comprised of a DC motor and a gear reducer. Aiming at improving ride comfort and reducing energy consumption, a multi-mode controller is established. According to the seat vertical acceleration and suspension dynamic travel signals, control strategies switch between three modes: active drive mode, energy harvesting mode and plug breaking mode.

The data shown in the previously published version of Figure 4 is from experiments performed with corn at 14%, rather than 21% as intended and indicated by the caption. The correct Figure 4, reflecting data from experiments performed with corn at 21%, should appear as shown in the erratum.

The capabilities of various numerical models to accurately account for the onset and development of cavitation in diesel injector nozzles is assessed and evaluated. The numerical predictions of the models are computed, and are compared to measured experimental data and observations. The numerical predictions for actual diesel nozzle geometry have been validated with experimental measurements of the total vapor mass flow rate. This vapor flow is found to be developed along the nozzle length due to the nucleation of the cavitation bubbles inside the diesel injector. The cavitation inception criteria that is used for the quantitative cavitation calculations included vapor quality, voidage, cavitation kinetic energy and cavitation energy. The results indicate that the cavitation simulation model predicts a diffused and gradual vapor distribution inside the nozzle in agreement with the experimental data.

This paper studies a control algorithm for fuel cell/battery city buses. The output power of the fuel cell is controlled by a D.C. converter, and the output ports of the converter and the battery are connected in parallel to supply power for the electric motor. One way to prolong service life is to have the fuel cell system to deliver a steady-state power. However, because of fluctuations in the bus voltage and uncertainness in the D.C. converter, the output power of the fuel cell system changes drastically. A closed-loop control algorithm is necessary to eliminate the errors between the output and target power of the fuel cell system. The algorithm is composed of two parts, the feed forward one and the feedback one. Influences of the bus voltage and D.C. efficiency are compensated automatically in the feedback algorithm by using a PI algorithm. The stability and robustness of the algorithm is analyzed.

Tyre behavior plays an important role in vehicle dynamics simulation. The Magic Formula Tyre Model is a semi-empirical tyre model which describes tyre behavior quite accurately in the handling simulation. The Magic Formula Tyre Model needs a set of parameters to describe the tyre properties; the determination of these parameters is nontrivial task due to its nonlinear nature and the presence of a large number of coefficients. In this paper, the homotopy algorithm is applied to the parameter identification of Magic Formula tyre model. A morphing parameter is introduced to correct the optimization process; as a result, the solution is directed converging to the global optimal solution, avoiding the local convergence. The method uses different continuation methods to globally optimize the parameters, which ensures that the prediction of the Magic Formula model can be very close to the test data at all stages of the optimization process.

The design of suspension affects the vehicle dynamics such as ride comfort and handling stability. Nonlinear characteristics and friction are important characteristics of suspension system, and the influence on vehicle dynamic performance cannot be ignored. Based on the seven-degree-of-freedom vehicle vibration nonlinear model with friction, the vibration response process of the vehicle and the influence of suspension friction on vehicle ride comfort and suspension action process were studied. The results show that friction will significantly affects the simulation of ride comfort and coincide with the function of the shock absorber. The suspension shock absorbers of vehicles were optimized with and without suspension friction. The results showed that the suspension tended to choose softer shock absorbers when there was friction. However, both of the two optimizations are able to improve the ride comfort of vehicles, and the simulation results were similar.

Elastomeric bushings are widely used in the passenger cars to make the cars have an ideal vehicle Noise, Vibration and Harshness (NVH) performance. However, elastomeric bushings also influence on the vehicle handling, ride and the durability performance of each component in the vehicle suspension system. It is relatively easy and cost effective to change the compliance of the bushing components compared with other method because they are made of elastomeric materials. The design of an elastomeric bushing is really a big challenge. One of the main difficulties comes from the different target compliance is wanted according to the handling, ride and durability demand at each different orientation (indicated by X Y Z) of the bushing. In this paper the following procedure was used for optimization of suspension elastomeric bushing compliance. Firstly, a detailed multi-body model was built including the nonlinear bushing effects and lower control arm flexibility.

Problems such as higher heat load in the diesel engine and the occurrence of crazes within the valve bridge of heavy-duty vehicle diesel engine should be solved, with the increase of the power density of heavy-duty vehicle diesel engine. In this paper, the heat load experiment of complete machine, temperature-measuring of bottom part of cylinder head and the three-dimension numerical simulation on coolant flow and heat transfer in the water jacket have been performed. The result shows that the main reasons of higher heat load of the engine are insufficiency of heat-sinking capability of the water-radiator and shortage of coolant flux; and the unsuitable flow field in water jacket in cylinder head, where only a little of the coolant can cool the bottom of cylinder head, is the main cause of cylinder head bottom over-heated and thermal crack in the valve-bridge region.

Lower engine emission is an important target in the evaluation of the control strategy of ECU. So the hardware in the loop simulation system (HILSS) including emission model is necessary. In this paper, a NOx emission neural network (NN) model is constructed based on the reflection relationship between the NOx formation and some direct influence factors such as concentration of oxygen, combustion temperature, combustion period. Combined with a nonlinear dynamic diesel engine model based on the filling and emptying methods, the NOx emission NN model can reach the trade-off between simulation accuracy and computational overhead. A new HILS platform based on Matlab/RTW and VxWorks real time operating system is introduced in the paper. The graphic programming and automatic code generating methods also developed to accelerate the development of HILSS.

Faced with the need to reduce development time and cost, the hardware-in-the-loop simulation increasingly proves to be an efficient tool in the development of automotive engine control system. In this article, the rapid prototyping technology is used to develop a hardware-in-the-loop simulation system for the diesel engine electronic control unit development. The hardware-in-the-loop simulation presented in this paper is based on Linux RTAI system, an open source hard real-time extension of the Linux Operating System, at low costs and within industrial standards. It exploits standard x86-based computing platforms provided with real-time Linux software in combination with generic computer-aided design software (Matlab/Simulink). One of its main characteristics is that it can automatically generate the real-time simulation code for many target processors, which runs under Linux RTAI operating system.

The homogenization of fuel, air, and recycled burnt gases prior to ignition as well as detailed intake, spray, combustion and pollution formation processes of Homogeneous charge compression ignition (HCCI) engine with liquid Dimethyl ether (LDME) fuel are studied by coupling multi-dimensional computational fluid dynamic KIVA-3Vr2 code with detailed chemical kinetics. An extended hydrocarbon oxidation reaction mechanism including 81 species and 362 elementary reactions used for (HCCI) engine fueled with (LDME) fuel was constructed and studded at different engine conditions by using CHEMKIN software and then a validating reduced mechanism that can be used in a modeling strategy of 3D-CFD/chemistry coupling for engine simulation is introduced to meet the requirements of execution time acceptable to simulate the whole engine physicochemical process including intake, spray, compression and combustion process.

HCNG is short for hydrogen enriched natural gas. Compared to traditional gasoline, diesel or even natural gas engines HCNG fuelled engines have several advantages on environment protection and energy security and in order to make full extent of the new fuel, several modifications have to be made in the corresponding engine and the control strategy. So there is a need to develop a predictive model to simulate the engine's performance without really running the engine, which could speed up the development of HCNG engines. This paper dose such a job. At first the paper presents the fundamentals of the quasi-dimensional model. The equations of the two-zone thermodynamic model and turbulent entrainment combustion model are both introduced. The methods of calculating the related parameters such as theoretical adiabatic flame temperature, laminar burning velocity of HCNG mixture under various hydrogen blending ratios are also given.

Based on linear stability analysis, this paper derived a dispersion equation which relates the disturbance growth rate to its wave number. Moreover, the dimensionless form and solution procedure of the dispersion equation were obtained. In order to improve the understanding of atomization mechanism of dimethyl ether (DME) jet, the instability of DME jet under normal and superheated conditions were analyzed in detail, and some valuable conclusions were made.

In this paper, a quasi-dimensional multi-zone spray combustion model is developed to simulate the combustion and emission of direct injection engine fueled with dimethyl ether (DME). The analysis of the spray mixing process is based on a quasi-dimensional gas jet model which consists of integral continuity and momentum equations. The heterogeneous field of temperature and temporal distribution histories of fuel in the combustion chamber is considered by dividing the chamber into n-zones. The jet mixing models are used to determine the amount of fuel and entrained air in each zone available for combustion. The mass, energy and state equations are applied in each zone and the combustion process is controlled by chemical reactions which are calculated by adopting CHEMKIN code. The CHEMKIN libraries have been used to formulate a stiff chemical kinetic solver suitable for integration within the engine cycle simulation.

Hydrogen enriched compressed natural gas (HCNG) is thought to be a potential alternative to common hydrocarbon fuels for SI engine applications. Experimental researches focusing on how to use this kind of fuel to its full extent have been conducted for over ten years and are still on their way. From a review of these researches it is found that one of the biggest obstacles of efficiently and economically conducting such experiments is how to mix desired amount of hydrogen with natural gas. Most of the previous experiments use pre-bottled hydrogen/ NG mixtures (by mixing and storing desired amount of hydrogen and NG in high pressure steel cylinders before the tests) which are quite costly and unsafe, due to high pressure operation. More importantly, the blending ratio cannot be varied by that approach. By comparison, this paper presents an on-line hydrogen-natural gas mixing system through which the hydrogen/ NG blending ratio can be easily varied during the tests.