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Technical Paper

Studies on Anti-Slip Regulation Technologies for AMT Vehicles

2007-04-16
2007-01-1314
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.
Technical Paper

Support Vector Machine Theory Based Shift Quality Assessment for Automated Mechanical Transmission (AMT)

2007-04-16
2007-01-1588
In China there is a strong trend in the application of vehicles equipped with automatic transmissions in considering the complexity of traffic and the convenience of automatic transmissions. As a type of automatic transmission, automated mechanical transmission (AMT) shows great potential to be developed as a main transmission because of its simple structures, easy upgrade from manual transmission (MT) and low price. Support Vector Machine (SVM) is a new statistic method which could make a good prediction with limited training instances. Compared with Artificial Neutral Network (ANN), SVM can provide better genetic ability. In order to verify the ability of the new method, the model trained by one set of AMT car data was applied on some other AMT vehicles, and the predicted results were compared with subjective rating results by expert drivers and analyzed to identify the potential of this new assessment system.
Technical Paper

A Novel Integrated Vehicle Chassis Controller Coordinating Direct Yaw Moment Control and Active Steering

2007-08-05
2007-01-3642
To optimally allocate control authorities to co-existing active actuators, an integrated chassis controller with main/servo-loop structure is designed to coordinate direct yaw moment control and active steering. Firstly, a sliding mode controller in the main-loop calculates the desired stabilizing forces. Then in the servo-loop, by directly considering limits of road friction and actuators, a quadratic programming based control allocation approach is adopted to reasonably and optimally distribute these deisired forces to tire actuator actions. Co-simulation of Matlab/Simulink and Carsim clarifies that the proposed controller could significantly improve vehicle handling performances.
Technical Paper

Research on Control of Vehicle Stability Control Based on Electro-Hydraulic Brake System

2007-08-05
2007-01-3650
Electro-Hydraulic Brake (EHB) system is a kind of active control brake systems of automobile, the pedal from the calipers actuation separated and no longer limited by conventional hardware. The system may come together with ABS, ESP, and ASR function, also the communication with other systems is done via the CAN network. EHB system may be classified a “stepping stone” technology to full brake-by-wire and brings huge transform for the performance of braking system. In this paper, vehicle dynamic models were established and accomplished the control strategy for vehicle stability control with EHB system which can adjust wheel and vehicle motion, improve the lateral and longitudinal vehicle stability. This result was verified by simulation which shows that the controller is effective on improving the vehicle stability.
Technical Paper

Yaw/Roll Stability Modeling and Control of HeavyTractor-SemiTrailer

2007-08-05
2007-01-3574
This paper sets up a simplified dynamic model for simulating the yaw/roll stability of heavy tractor-semitrailer using Matlab/Simulink. A linear quadratic regulator (LQR) based on partial-state feedback controller is used to optimize the roll stability of the vehicle. The control objective for optimizing roll stability is to be reducing the lateral load transfer rate while keeping the suspension angle less than the maximum allowable angle. The simulation result shows that the LQR controller is effective in the active roll stability control of the heavy tractor-semitrailer.
Technical Paper

Study on the Straight-line Running Stability of the Four-wheel Independent Driving Electric Vehicles

2007-08-05
2007-01-3488
The motor errors of the four-wheel independent driving electric vehicles was studied, and classified as steady errors and dynamic errors. In the paper, the forward compensation control and the PID control strategy were respectively applied to compensate for the errors. The electric vehicles straight-line running stability caused by the motor errors was discussed, the PID control method based on BP neural net work was presented to co-ordinate torque of the wheels. The result of the simulation on the 7 degrees of freedom vehicle model showed that control method improved the straight-line running ability of the vehicle.
Technical Paper

The Research on Fuzzy Logic Control Strategy of Synergic Electric System of Hybrid Electric Vehicle

2007-08-05
2007-01-3481
Supercapacitor has the merits of low resistance and long lifecycle ability. When combined with battery, they can alleviate the burthen of battery, increase the battery's working efficiency and prolong its lifecycle. This paper introduces a control architecture based on balancing of SOC and algorithm based on fuzzy logic, Aiming at the two different cycles that have sufficient and insufficient energy that can be recovered from braking unlikely, this paper puts forward the methods of on-line adjusting fuzzy control parameters. Consequently, simulation was performed,and the results validate the effective adapting capacity of the control logic under different driving cycles.
Technical Paper

Effect of Piston Crevice on Transient HC Emissions of First Firing Cycle at Cold Start on LPG SI Engine

2007-10-29
2007-01-4015
By changing the top-land radial clearance, this paper presents the effect of the piston crevice on the transient HC emissions of the first firing cycle at cold start on an LPG SI Engine. A fast-response flame ionization detector (FFID) was employed to measure transient HC emissions of the first firing cycle. At the same time, the transient cylinder pressure and instantaneous crankshaft speed of the engine were measured and recorded. The results show that increasing 50% crevice volume leads to 25% increase of HC emissions in the lean region and 18% increase of HC emissions in the rich region, however, the 50% increase of crevice volume contributes to 32% decease of HC emissions in the stable combustion region. For LPG SI engine, the HC emissions of the first firing cycle during cold start are relatively low in a wide range of the excess air ratio.
Technical Paper

A Study of LPG Lean Burn for a Small SI Engine

2002-10-21
2002-01-2844
This paper presents a study of LPG lean burn in a motorcycle SI engine. The lean burn limits are compared by several ways. The relations of lean burn limit with the parameters, such as engine speed, compression ratio and advanced spark ignition etc. are tested. The experimental results show that larger throttle opening, lower engine speed, earlier spark ignition timing, larger electrode gap and higher compression ratio will extend the lean burn limit of LPG. The emission of a LPG engine, especially on NOx emission, can be significantly reduced by means of the lean burn technology.
Technical Paper

Performance Simulation Research on Bus with Air Suspension

2002-11-18
2002-01-3093
Air spring has a variable stiffness characteristic, its vibration frequency is much lower than that of leaf spring and will not vary with load of vehicle. More and more air springs are applied on automobile suspension. A study on the automobile ride comfort, and the controllability and stability about the bus with air suspension is performed in the paper, which is based on multi-body system dynamics.
Technical Paper

A Study on Nonlinear Stiffness Characteristic of Air Spring for a Bus

2002-11-18
2002-01-3092
Using the nonlinear finite element analysis, three nonlinear characteristics of the rubber gasbag of the air spring on the bus are thoroughly analyzed, including the nonlinear characteristic of the rubber gasbag with multi layers of composite materials, the nonlinear large displacement geometry characteristic of the rubber gasbag on working, and the nonlinear contact characteristic of the rubber gasbag when contacts the pedestal and the top cover plate. A model is build and the nonlinear characteristic of the air spring on the bus is analyzed using the ABAQUS software. At last, the article discusses parameters that influence on the characteristic of the air spring for the bus.
Technical Paper

On-Line StatePrediction Of Engines Based On Fast Neural Network

2001-03-05
2001-01-0562
A flat neural network is designed for the on-line state prediction of engine. To reduce the computational cost of weight matrix, a fast recursive algorithm is derived according to the pseudoinverse formula of a partition matrix. Furthermore, the forgetting factor approach is introduced to improve predictive accuracy and robustness of the model. The experiment results indicate that the improved neural network is of good accuracy and strong robustness in prediction, and can apply for the on-line prediction of nonlinear multi input multi output systems like vehicle engines.
Technical Paper

A Study of Calculation Method of Wheel Speed and Wheel Angular Acceleration Based on dSPACE Rapid Control Prototyping in Modern Automotive Control Systems

2006-10-31
2006-01-3547
One of the key technologies of automotive active safety systems is to calculate the wheel speed and wheel angular acceleration or deceleration. Obtaining an accurate control quantity is the prerequisite for active safety systems no matter what control logics are used to realize the control function. This paper puts forward a new wheel speed processing algorithm. This method was simulated in MATLAB \ Simulink. Then it was tested in a certain type of vehicle of FAW by applying dSPACE RCP. It proves that this algorithm assures the precision at high and low speed and the real-time performance at low speed.
Technical Paper

Analysis of Common Rail Pressure Build-Up and Assistant-Establishment of Engine Phase Position in Starting Process

2006-10-31
2006-01-3525
Rapid pressure build-up before acquiring the engine phase position is necessary to improve the start performance for a common rail diesel engine. This paper presents a simulation model to describe the pressure build-up process of the DENSO HP0-MD high-pressure pump, with the two pressure-control-solenoid-valves (PCV) are frequently driven in sequence. As the fuel is pumped only when one PCV is energized in its corresponding plunger supply stroke, simulation studies are carried out to analyze the pressure build-up effect of different driving frequency, and the 30Hz frequency is selected as the optimal driving frequency to achieve about 80% fuel supply efficiency for the normal cranking speed range. Additionally, when only the crankwheel signal is useful, a novel method, which checks whether the rail pressure rises in a special PCV energizing zone, is designed to assistant ascertain engine phase.
Technical Paper

Virtual Simulation Research on Vehicle Ride Comfort

2006-10-31
2006-01-3499
In this paper, a computer model of a multi-purpose vehicle (MPV) is built to study vehicle ride comfort by multi-body system dynamic theory. Virtual test rigs are developed to perform natural body frequency tests and random road input tests on the complete vehicle multi-body dynamic model. By comparing simulation results with field test results, the accuracy of the model is validated and the feasibility of virtual test rigs is established.
Technical Paper

CAN Communication Applying on the Performance Evaluating of Electronic Brake System for Commercial Vehicle

2006-10-31
2006-01-3582
In the performance evaluating of Electronic Brake System, conventional test methods have some inconvenience in existence. For example, the fixing of pressure sensors and wheel speed sensors is restrained by the installation position, and the precision of measuring is prone to be affected by the environment conditions. Since Electronic Brake System is featured by CAN (Controller Area Network) communication, special testing instrument can be connected with CAN bus, monitoring signals transmitting on the bus. This paper outlines the results of the study performed to analyze the application of CAN communication in the way of performance evaluation of Electronic Braking System.
Technical Paper

Advanced Braking Control System for Hybrid Electric Vehicle Using Fuzzy Control Logic

2006-10-31
2006-01-3583
During braking, energy regeneration for hybrid electric vehicles (HEV) is an important technique to improve their fuel economy and extend their driving range. Due to the effect of regenerative braking torque added by the electric motor, the control logic of the braking system should be adjusted. This paper presents a control strategy for an HEV braking system, which calculates the optimal target wheel slip ratio based on vehicle dynamic states; a fuzzy logic approach is applied to maintain the optimal target slip ratio so that the best compromise between hydraulic braking torque and regenerative braking torque can be obtained for the vehicle. This control strategy is implemented with an 8-DOF nonlinear vehicle model and a “Magic Formula” tire model; the simulation results show that the proposed strategy is robust and effective.
Technical Paper

Robust Scheduler Design for Automatic Mechanical Transmission Real-time Control

2006-04-03
2006-01-1490
Since the vehicle AMT(Automatic Manual Transmission) has been developed to meet the requirements of high quality vehicles as well as hybrid vehicles, there are more and more tasks running on the ECU (Electronically Controlled Unit). Concerned with both function correctness and timing correctness, the scheduling of those tasks becomes important. A perfect scheduler, which distributes the proper task working during the proper time, can not only make the best use of the ECU, but also predict its capacity rationally. Compared with ordinary algorithm such as clock driven scheduler, static and dynamic priority-driven scheduler as well as round robin scheduler, this paper proposes an offline-designed Blended Timer-triggered Scheduler (BTTS) for AMT control. BTTS can coordinate periodical and event-triggered tasks in one envelope. It designates the available time slice for each task, which can make each critical task run at the proper time.
Technical Paper

Real-time Analysis for Electronically Controlled Unit of Vehicle Automatic Mechanical Transmission

2005-11-01
2005-01-3589
Real-time theory is introduced to analyze reliability and robustness for ECU (Electronically Controlled Unit) of vehicle AMT (Automatic Mechanical Transmission). Real time analysis architecture is proposed. Analysis and simulation for the four working stages of AMT are illustrated. The results show, the real time system model with 9 tasks working on 4 processors is reasonable, and the designed Blended Timer-Triggered Scheduler is feasible as well as robust, which provide the system more extendibility and reliability.
Technical Paper

Matching Optimum for Low HC and CO Emissions at Warm-up Phase in an LPG EFI Small SI Engine

2005-10-24
2005-01-3897
Based on a 125cm3 single cylinder SI engine, the designated idle speed was controlled by adjusting of cycle ignition advance angle. By analyzing the effects of different idle speed and throttle open position on three way catalyst (TWC) light-off time and conversion efficiency of HC and CO emissions, combined with the corresponding total HC and CO emissions level, the optimum idle speed and throttle open position at engine's warm-up phase were found by the matching optimum. The present method for engine control strategy is helpful to optimize the warm-up phase emission levels in SI engine with LPG fuel.
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