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How to control and analyze the turning process of a tracked vehicle with electric transmission system is an important issue. In the paper two turning control methods are presented according to its study. The balance relations of its tractive effort and power versus radius are obtained by the calculation with using the mathematical model of basic turning dynamics and constraint conditions. The model of continuously variable radius turning is implemented by a RBF neural network which is of the better identifying ability, and the more turning results can be given from it. These turning analyses are significant for the electric transmission system.

In this paper, a new method for the driving of the hydraulic free piston engine (HFPE) is proposed. Hydraulic differential drive achieves the compression stroke automatically rather than special recovery system, which has a great influence on the engine dynamic performance. The purpose of this paper is to solve the key operation and control problems for HFPE to commix fuel with air. HFPE adopts two-stroke loop-scavenging and semi-direct injection. The semi-direct injection nozzle is located in the liner wall inside the main intake port, with the axes oriented towards the piston at the Bottom Dead Center (BDC). Different scavenging pressures and injection angles result in different impacts on the mixture of fuel and air in the cylinder. This study analyzes the changes of the combustion heat release rate by simulation.

Ignition location is one of the important factors that affect the thermal efficiency, exhaust emissions and knock sensitivity in premixed-charge ignition engines. However, the ignition initiation locations of pre-chamber generated turbulent jet ignition, which is a promising ignition enhancement method, are not clearly understood due to the complex physics behind it. Motivated by this, the ignition initiation location of a transient turbulent jet in a constant volume combustor is analyzed by the use of computational fluid dynamics (CFD) simulations. In the CFD simulations of this work, commercial codes KIVA-3 V release 2 and an in-house-developed chemical solver with a detailed mechanism for H2/air mixtures are used. Comparisons are performed between simulated and experimental ignition initiation locations, and they agree well with one another. A detailed parametric study of the influence of in-cylinder temperature on the ignition initiation location is also performed.

Urea SCR technology is the most promising technique to reduce NOx emissions from heavy duty diesel engines. 32.5wt% aqueous urea solution is widely used as ammonia storage species for the urea SCR process. The thermolysis and hydrolysis of urea produces reducing agent ammonia and reduces NOx emissions to nitrogen and water. However, the application of urea SCR technology has many challenges at low temperature conditions, such as deposits formation in the exhaust pipe, lack deNOx performance at low temperature and freezing below -12°C. For preventing deposits formation, aqueous urea solution is hardly injected into exhaust gas stream at temperature below 200°C. The aqueous urea solution used as reducing agent precursor is the main obstacle for achieving high deNOx performances at low temperature conditions. This paper presents a solid SCR technology for control NOx emissions from heavy duty diesel engines.

This paper describes the application of Human Simulation Intelligent Control(HSIC) method to improve the idle speed performance of heavy-duty diesel engines on the basis of diesel engine electronic control system. The HSIC is a kind of intelligent control method which can be used without knowing the system's model and it can on line choose control models and it is also easy to be used under the condition of diesel engine electronic control system. In our system, we used electronic control system to control fuel quantity by double loop control of pump rack position and engine speed. From the experimental results, The engine minimum idle speed has been reduced from 800 rpm at first to 500 rpm, and the speed fluctuation have been reduced by 50 percent. From the system's design and test, the simplicity and efficiency of the HSIC control method were demonstrated.

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.

Hydrodynamic torque converter parameter integrated optimization design system is established based on tri-dimensional flow field theory. Design segments such as optimization initial values searching by meanline theory, cascade solid modeling, structure mesh of flow passage, CFD(computational fluid dynamics), DOE(design of experiment), RSM(response surface model)and optimization algorithm are integrated in this system and therefore a three dimensional optimization design method for hydrodynamic torque converter is presented and realized. An optimization design instance is accomplished by workstation computer cluster, and its result shows that speed and accuracy of design are improved and design system based on 3D flow field theory is accurate and effective.

In order to improve the tractive ability, steering capability and directional stability, etc. of automated mechanical transmission (AMT) vehicles running on the wet and slippery road, the anti-slip regulation (ASR) technologies for AMT vehicles are developed. The significance of ASR for AMT vehicles is introduced; a road friction recognition method based on the deceleration of driving wheels is investigated; a fuzzy anti-slip control system based on adjustment of engine torque is developed and the corresponding experimental verification is conducted. The experimental results denote that the proposed method is effective to eliminate the excessive slip when the AMT vehicle travels on the low friction road.

Due to the poor ability of millimeter wave radar in recognizing distant static objects, target loss and incomplete information will occur when it recognizes the static target in front, thus increasing the false alarm rate and missing alarm rate of the radar-dependent driving assistant system, which will reduce the driving safety and the acceptability of the assistant system. Aiming at the radar's poor ability to recognize static targets, this paper uses a model based on machine learning algorithm to recognize and track targets. The radar signals are collected and processed in different conditions, and the results show that the radar has a poor recognition effect when the distance is more than 100 meters and the speed is more than 19m/s.

The study of controllable suspension properties special in the characteristics of improving ride comfort and road handling is a challenging task for vehicle industry. Currently, since most suspension control requires the observation of unmeasurable state, how to accurately acquire the state of a suspension system attracts more attention. To solve this problem, a novel approach interacting multiple mode Kalman Filter (IMMKF) is proposed in this paper. Suspension system parameters are crucial for the performance of state observers. Uncertain suspension system parameters in various conditions, e.g. due to additional load, have significant effect on state estimation. Simultaneously, state transition among different models may be happened on the condition of varying system parameters.

The spray structure and vaporization processes of flash-boiling sprays in a constant volume chamber under a wide range of superheated conditions were experimentally investigated by a high speed imaging technique. The Engine Combustion Network’s Spray G injector was used. Four fuels including gasoline, ethanol, and gasoline-ethanol blends E30 and E50 were investigated. Spray penetration length and spray width were correlated to the degree of the superheated degree, which is the ratio of the ambient pressure to saturated vapor pressure (pa/ps). It is found that parameter pa/ps is critical in describing the spray transformation under flash-boiling conditions. Three distinct stages namely the slight flash-boiling, the transition flash-boiling, and the flare flash-boiling are identified to describe the transformation of spray structures.

Particulate matter emissions are becoming a big issue for GDI engines as the emission regulations being more stringent. Methanol has been considered to be an important alternative fuel to reduce soot emissions. To understand the effect of methanol addition on soot and polycyclic aromatic hydrocarbons (PAHs) formation, the 2-D distributions of soot volume fraction and different size PAHs relative concentrations in methanol/gasoline laminar diffusion flames were measured by TC-LII and PLIF techniques. The effect of methanol was investigated under the conditions of the same carbon flow and the same flame height. The methanol volume fraction was set as M0/20/40/60/80. The results showed that the natural luminescent flame lift-off height and soot lift-off height increases consistently with the increasing methanol content due to the increase of outlet velocity of fuel vapor.

Electric Power-Assisted Steering (EPAS) is a new power steering technology that will define the future of vehicle steering. The assist of EPAS is the function of the steering wheel torque and vehicle velocity. The assist characteristic of EPAS is set by control software, which is one of the key issues of EPAS. The straight-line type assist characteristic has been used in some current EPAS products, but its influence on the steering maneuverability and road feel hasn't been explicitly studied in theory. In this paper, the straight-line type assist characteristic is analyzed theoretically. Then a whole vehicle dynamic model used to study the straight-line type assist characteristic is built with ADAMS/Car and validated with DCF (Driver Control Files) mode of ADAMS/Car. Based on the whole vehicle dynamic model, the straight-line type assist characteristic's influence on the steering maneuverability and road feel is investigated.

The hydraulic free piston engine is a complex mechanical-electro-liquid system, in order to simplify the complex system of the single hydraulic free piston engine, a new method for the driving of hydraulic free piston engine is proposed. Hydraulic differential drive achieves the compression stroke automatically rather than special recovery system. The structure and principle of hydraulic differential drive free-piston engine are analyzed and the mathematical model is established based on the piston force analysis and the hydraulic system working principle. In addition, the control strategy of this novel hydraulic driving engine is also introduced. Finally, the transient results of dynamics are obtained through simulation. Then we compare our results to the ones from the hydraulic free piston engine made by the company Innas.

In this paper, a new-type balanced opposed-piston two-stroke (OP2S) gasoline direct injection (GDI) engine is developed by Beijing Institute of Technology. OP2S-GDI engine has some potential advantages such as simple structure, good balance, compact, high power density and thermal efficiency. The structural feature of OP2S-GDI engine leads to the performance difference compared with conventional engines. In order to study and verify the characteristics of this kind of engine, the dynamics characteristics and design scheme of opposed crank-connecting rod mechanism, in-cylinder scavenging process, mixture formation and combustion process are investigated. The influence of parameters on engine performance is investigated, including opposed-piston motion phase difference, intake and exhaust port timing, injection and ignition timing.

In this paper, the finite element model for static analysis of an electric tractor's frame is presented firstly, and the rigidity and strength of one electric tractor's frame is calculated. Based upon the analysis results, the topology and shape of this electric tractor's frame is optimized. As to the topology optimization, the optimization goal under multiple load cases is defined and the frame is optimized by two steps-one is to determine the position of the transverse rails using solid elements which can simulate the material-filling space, another is to obtain the shape of the frame in which shell elements are applied as to increase the calculation efficiency. After the topology optimization the frame's stiffness is improved significantly but there still is local stress concentration. So the shape of the stress concentration area is optimized using control points method, and the greatest stress is reduced below the strength limits.

This research examined the focused design, elastic design, energy decoupling, and torque roll axis (TRA) decoupling methods for mount optimization design. Requiring some assumptions, these methods are invalid for some load conditions and constraints. The linearity assumption is advantageous and simplifies both design and optimization analysis, facilitating engineering applications. However, the linearity is rarely seen in real-world applications, and there is no practical method to directly measure the reaction forces in the three locally orthogonal directions, preventing validation of existing methods by experimental results. For nonlinear system identification, there are additional challenges such as unobservable internal variables and the uncertainty of measured data.

The method and steps for software modeling of the embedded control systems for diesel engine based on UML are described in this paper. In order to meet the software function and the features of the system, object-oriented modeling for diesel engine embedded control software system has been implemented. Requirements are depicted by use case diagram and the logic structure is depicted by class diagram. According to the domain knowledge and the class diagram, the sequence diagram and state diagram are developed to describe the dynamic behavior of the system. The level of software development has been enhanced to the system level by software modeling. It focuses on the automotive field, and can be easy to grasp the problem from the overall perspective and discover software design problems at the early stage. It is also convenient to solve the problems caused by the change of requirements. The model has an excellent flexibility so that it can be applied to different software platforms.

The cylinder-by-cylinder variations have many bad impacts on the engine performance, such as increasing the engine speed fluctuation, enlarging the torsional vibration and noise. To deal with this problem, the impact mechanism of cylinder-by-cylinder variations on low order torsional vibration has been studied in this paper, and subsequently a new individual cylinder control strategy was designed by processing the instantaneous crankshaft rotation speed signal, detecting the cylinder-by-cylinder variation and using feed-back control. The acceleration characteristics of each cylinder in each engine cycle were compared with each other to extract the variation index. The feed-back control algorithm was based on the regulation of the fuel injection according to the detected variation level.

To reduce the energy consumption level of electric vehicles, the working range of the regenerative braking system will gradually expand to the high state of charge of the battery. The time delay in the control signal transmission path of the high state of charge regenerative braking control process will affect the regenerative braking. At the same time, regenerative braking under a high state of charge puts forward higher requirements for the control accuracy of regenerative current. In the research of this paper, the motor model, battery model, and vehicle dynamics model are firstly established by using MATLAB/Simulink, and the dynamic relationship between regenerative current and regenerative braking torque is analyzed at the same time. Considering the system time delay, this paper proposes a high-charge regenerative braking control strategy (SPPC) that combines Smith prediction and prescribed performance control.