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Technical Paper

The Modeling and Performance Analysis of the Retarder Thermal Management System

2012-09-24
2012-01-1929
In order to obtain the comprehensive evaluation of thermal management system for the retarder, the complete driveline thermal management model is built. The characteristic parameters for the thermal management system are determined and the hydromechanical characteristics for the retarder are fixed by the rig test. On the basis of the same whole vehicle driving cycle, comparing to the traditional mechanical-drive system, the independent-drive system makes the working temperature of the heat source more stable. Meanwhile the parasitic power caused by the radiator fan is decreased markedly on the condition that the heat reject requirement of the heat source is satisfied.
Technical Paper

Application of Wavelet Analysis in Truck Cab Vibration Signal Processing

2012-09-24
2012-01-2011
The basic principle of wavelet transform is presented and the method of wavelet theory is used in vibration signal analysis of vehicle in this paper. The vibration signals which generated in the locations such as cab floor, engine, transmission, band spring and frame under the usual work condition are measured by the vibration test system. The vibration signals are decomposed with the principle of wavelet decomposition at level six, and eigenvectors of signal energy are gained. According to the correlation coefficient of eigenvectors of signal energy distribution, two signals correlativity is determined. It could be an effective method that identificate the main vibration source.
Technical Paper

Vehicle Braking System Calculation and Simulation Software Platform

2012-09-24
2012-01-1895
The brake performance is one of the most important performances in the automotive active safety, and it is the main measure of automotive active safety. Thus, to develop a platform for the braking system is quite significant. Based on the object-oriented technology, the platform for braking system is developed by making use of Visual C++ 6.0 development tool. By using the VC++ development tool and doing secondary development on other softwares, the software possesses powerful features, such as brake plan selection, performance calculation, parametric modeling, finite element analysis and kinematics simulation, etc. An initial brake system can be designed, calculated and analyzed all in one. The living instance shows that the platform has friendly user interfaces, powerful functions and it can improve the precision and efficiency of brake design. The platform has been of great applied value and can also positively promote the design automation of vehicle's braking system.
Technical Paper

Study on Variable Combustion Chamber (VCC) Engines

2012-09-10
2012-01-1607
A patented VCC (variable combustion chamber) piston mechanism is presented, by which excess in-cylinder pressure would be able to be limited effectively based on each working cycle while a spark-ignition engine running with higher CR (compression ratio) of 12.0:1. A conventional engine can be converted to a VCC engine just by replacing its typical pistons with VCC pistons. Besides the benefits that VCR (Variable Compression Ratio) has been still pursued so far, there would be other advantages for VCC engine, such as excellent fuel economy at each load not only at light loads, and the improvement of cycle-by-cycle variation of in-cylinder pressure, and high reliability with simple structure. The innovative design of VCC piston is introduced. The main design features of VCC piston are a VCC mechanism assembled between the piston crown and the piston skirt, and a special reset cam assembled at the wrist-pin end of the connecting rod.
Technical Paper

The Selection of Working Fluid Used in the Organic Rankine Cycle System for Hydraulic Retarder

2016-04-05
2016-01-0187
With the improvement of occupants’ awareness on the driving safety, hydraulic retarder applications increase quickly. The traditional hydraulic retarder, on the one hand, exhausts the waste heat of transmission oil by the engine cooling system; on the other hand, the engine power should be consumed to drive the water pump and the engine cooling fan for maintaining the normal operation of the auxiliary braking system. In this study, the Organic Rankine Cycle (ORC) instead of the traditional hydraulic retarder water-cooling system is applied to achieve the effective temperature control of the hydraulic retarder, while the waste heat of transmission oil could be recovered for saving vehicle energy consumption. The ORC fluid selection needs comprehensive consideration for the net power of the ORC and the optimal temperature range of the retarder transmission oil at both the inlet and outlet end, which is the key issue to ensure the stability and efficiency of the ORC system performance.
Technical Paper

Effects Analysis and Modeling of Different Transmission Running Conditions for Transmission Efficiency

2016-04-05
2016-01-1096
Several factors including internal factors which are related to the structure and components of transmission and external factors which are related to the running condition influence transmission efficiency (TE) collectively. Selected one manual transmission as the research object, this paper mainly analyzes factors including gears and bearings power loss through theoretical calculation and the external factors, such as gears, temperature and torque. Firstly, with a methodology, the overall efficiency of the manual transmission is calculated based on factors. Then, this paper discusses efficiency through external factor. This transmission is experimented on transmission test bench. On the bench, the driving motor (DM) simulates the power input of engine and the load motor (LM) simulates the whole resistance of vehicle. The mechanical transmission is operating in different speeds, torques and work temperature, thus the corresponding data are obtained.
Technical Paper

A Modeling Study of the Effects of Butanol Addition on Aromatic Species in Premixed Butane Flames

2016-04-05
2016-01-0574
The motivation of the present work was to understand the mechanism by which alcohols produce less aromatic species in their combustion process than an equal amount of hydrocarbon with similar molecular structure does. Due to its numerous advantages over short-chain alcohols, butanol has been considered very promising in soot reduction. Excluding the influence of spray, vaporization and mixing process in engine cases, an adiabatic constant-pressure reactor model was applied to investigate the effect of butanol additives on aromatic species, which are known to be soot precursors, in fuel-rich butane flames. To keep the carbon flux constant, 5% and 10% oxygen by mass of the fuel were added to butane using butanol additive, respectively. Based on the soot reduction effects proposed in literature, effects on temperature, key radical concentrations and the carbon removal from the pathway to aromatic species were considered to identify the major mechanism of reduction in aromatic species.
Technical Paper

Driving Fatigue Detection based on Blink Frequency and Eyes Movement

2017-03-28
2017-01-1443
The development of the vehicle quantity and the transportation system accompanies the rise of traffic accidents. Statistics shows that nearly 35-45% traffic accidents are due to drivers’ fatigue. If the driver’s fatigue status could be judged in advance and reminded accurately, the driving safety could be further improved. In this research, the blink frequency and eyes movement information are monitored and the statistical method was used to assess the status of the driving fatigue. The main tasks include locating the edge of the human eyes, obtaining the distance between the upper and lower eyelids for calculating the frequency of the driver's blink. The velocity and position of eyes movement are calculated by detecting the pupils’ movement. The normal eyes movement model is established and the corresponding database is updated constantly by monitoring the driver blink frequency and eyes movement during a certain period of time.
Technical Paper

Modeling and Simulation Research of Dual Clutch Transmission Based On Fuzzy Control

2007-08-05
2007-01-3754
Dual-Clutch-Transmission (DCT) is one kind new automatic transmission which has double clutch structure. The most important unit of DCT is Transmission-Control-Module (TCM).In the development process of TCM, simulation is an important research tools. We have analyzed the DCT principle of work, established its mathematical model, created the charge and discharge oil models of typical wet dual clutch transmission, established the control logic to unify and separate double clutch in turn, and also designed out the shift control using fuzzy control using MATLAB/Simulink software. Utilizing engine model, driver model, the DCT model, the TCM model, the vehicle model, established the vehicle simulation model, and implemented simulation; Result indicated that, the established model can correctly reflect the torque and speed change when shifted gears and can correctly realize the automatic shift gears.
Technical Paper

Research on cooling system for 4-cylinder diesel engine

2007-07-23
2007-01-2064
Coolant flow and its heat transfer directly affect the cooling efficiency, thermal load of heated components as well as thermal efficiency of diesel engine. An efficient approach to study cooling system for diesel engine is 3D CFD calculation for coolant jacket and 1D cooling system simulation. The velocity, pressure and heat transfer coefficients (HTC) distribution in the coolant jacket of a 4 cylinder diesel engine are computed by 3D CFD approach using AVL/FIRE software. The improved schemes can be put forward according to calculating results. The boundary condition of 1D cooling system for diesel engine can be obtained by averaging computed inlet and outlet total pressure drop and heat transfer coefficients from CFD calculation. The parameters of the engine, which are fitted with the vehicle such as capacity of radiator, fan and water pump, could be decided.
Technical Paper

Analysis and Evaluation of the Urban Bus Driving Cycle on Fuel Economy

2007-07-23
2007-01-2073
On-road testing of driving performance of the urban bus was carried out, and a representative urban bus driving cycle was developed after on-road testing, according to the test results. Then, the vehicle simulation software AVL CRUISE was used to simulate the dynamic behavior of the urban bus. It involves the simulation of complete drive train system and the driver behavior. The model is validated by comparing the results of the simulation to the results of the field test. Then the developed driving cycle is evaluated by fuel consumption resulted from the simulation and engine bench test on fuel economy.
Technical Paper

The Application of the PUREM SCR System on YC6L350-40 HD Diesel Engine

2007-07-23
2007-01-1935
In order to meet the Euro IV HD diesel engine emission standard legislation limits, an efficient SCR system is adopted for PM optimized YC6L350-40 HD diesel engine serving in China. This paper presents tests made on the engine. The engine had base NOx emission of 8.8g/kwh over the ESC and 8.7g/kwh over the ETC. Outfitted with a 24.7 liter 300cpsi SCR catalyst, the engine NOx emission dropped to 3.2g/kwh over the ESC and 3.5g/kwh over the ETC.
Technical Paper

3-D Numerical Simulation of Transient Heat Transfer among Multi-Component Coupling System in Internal Combustion Chamber

2008-06-23
2008-01-1818
A 3-D numerical analysis model of transient heat transfer among the multi-component coupling system in combustion chamber of internal combustion engine has been developed successfully in the paper. The model includes almost all solid components in combustion chamber, such as piston assembly, cylinder liner, cylinder head gasket, cylinder head, intake valves and exhaust valves, etc. With two different coupling heat transfer modes, one is the lubricant film heat conduction between two moving components, another is the contact heat conduction between two immovable solid components, and with the direct coupled-field analysis method of FEM, the heat transfer relation among the components is established. The simulation result dedicates the transient heat transfer process among the components such as moving piston assembly and cylinder liner, moving valves and cylinder head. The effect of cylinder head gasket on heat transfer among the components is also studied.
Technical Paper

Body Load Identification for BEV Based on Power Spectrum Decomposition under Road Excitation

2014-06-30
2014-01-2044
As motor assembly of Battery Electric Vehicle (BEV) replaces engine system of Internal Combustion Engine (ICE) vehicle, interior structure-borne noise induced by road random excitation becomes more prominent under middle and high speed. The research is focused on central driving type BEV. In order to improve interior noise in middle and low frequency range, dynamic load of BEV body must be identified. Consequently the structural noise induced by road excitation is conducted. The limitations of common identification method for dynamic body load are analyzed. The applied several identification methods are proposed for deterministic dynamic load such as engine or motor. Random dynamic load generated by road excitation is different from deterministic dynamic load. The deterministic load identification method cannot be applied to the random load directly. An identification method of dynamic body load for BEV is presented based on power spectrum decomposition.
Technical Paper

The Experimental Study and Performance Analysis of Air-Friction Reduction System for Hydraulic Retarder

2015-04-14
2015-01-1127
The hydraulic retarder is an important auxiliary braking device for the heavy vehicle, which has some characteristics, such as the big brake torque and long duration braking, when the vehicle is traveling in braking state. However, the transmission power loss will be produced when the vehicle is traveling in non-braking state. This transmission power loss is called Air-friction. Firstly, the air flow distribution characteristics of retarder cavity are studied by computational fluid mechanics, and the Air-friction characteristic in different conditions is analyzed. Then, according to the Air-friction characteristics for the condition of different filling density, a set of vacuum air loss reduction system is designed. Meanwhile, the test bench for retarder Air-friction is set up, the test data of the revolution speed, pressure in cavity and air loss resistance is obtained according to the test bench for hydraulic retarder.
Technical Paper

Intelligent Control of Metal-belt CVT Based on Fuzzy Logic

2009-04-20
2009-01-1535
Operating level of a metal-belt CVT mainly rest with the ECU. Conventional control strategies which were obtained from tests or PID controller can not correspond to the driver’s intention or provide various driving environments. It is considered that control targets of metal-belt CVT could be distinguished by a speed ratio, line pressure and starting element till now. Running performance of automobile with a CVT mainly depends on the speed ratio control. An adapted fuzzy logic ratio control algorithm is suggested and optimized. A throttle position and its changing rate will be inputs of the FLC to meet the driver’s intention and make the intelligent control come true. A fuzzy logic line pressure control algorithm is also suggested and optimized corresponding to the complicated high line pressure control.
Journal Article

A Wavelet Neural Network Method to Determine Diesel Engine Piston Heat Transfer Boundary Conditions

2012-09-10
2012-01-1760
This paper presents a method of calculating temperature field of the piston by using a wavelet neural network (WNN) to identify the unknown boundary conditions. Because of the complexity of the heat transfer and limitations of experimental conditions of heat transfer analysis of the piston in a diesel engine, boundary conditions of the piston temperature field were usually obtained empirically, and thus the result itself was uncertain. By employing the capability of resolution analysis from a wavelet neural network, the method obtains improved boundary heat transfer coefficients with a limited number of measured temperatures. Using FEA software iteratively, results show the proposed wavelet neural network analysis method improves the prediction of unknown boundary conditions and temperature distribution consistent with the experimental data with an acceptable error.
Technical Paper

Strength Analysis and Structural Optimization of Lever of Air Disc Brake

2014-09-28
2014-01-2507
Air disc brake (ADB) is the execution unit of automobile brake, which plays a vital role in traffic safety. Lever is a very important driving as well as stress part of ADB. However, seldom periodical or thesis has given specifications about the lever. In this paper, working principle of the lever is illustrated in detail. Finite element analysis (FEA) of the lever is conducted and some structural problems of the lever are found out. Finally, for the condition that the lever doesn't meet the strength requirement, topography optimization is introduced to improve the shape of lever. Simulation results show that the strength of the lever improved obviously with the optimization, and analysis method as well as optimization method in this paper is feasible.
Technical Paper

Cold-end Temperature Control Method for the Engine Exhaust Heat Thermoelectric Module

2014-09-30
2014-01-2343
To make full use of engine exhaust heat and further improve the utilization of the energy efficiency of the heavy truck, thermoelectric module is used to contribute to thermoelectric power generation. The hot-end temperature of the module varies with the engine operating condition because it is connected with the exhaust pipe. The cold-end of the thermoelectric module is mainly cooled by engine cooling system. Increasing the temperature difference between the hot-end and cold-end of the thermoelectric module is a good way to improve the thermoelectric conversion efficiency. For the poor controllability of the hot-end temperature of the thermoelectric module, this study puts forward by lowering the cold-end temperature of the thermoelectric module so as to ensure the improvement of the thermoelectric conversion efficiency. The cooling circle for the cold-end of the thermoelectric module which is independent of the engine cooling system is built.
Technical Paper

Engine Cycle Simulation and Development Engine of a Gasoline

2007-10-29
2007-01-4103
In order to acquire low fuel consumption while the engine is running at low speeds and maintain the high power output of the traditional 4-valve engine at high speeds, multiple camshafts were applied in gasoline engines. An engine cycle simulation process of a gasoline engine with multiple camshaft profiles was presented in this paper. Engine cycle models were set up to describe external characteristic at 14 different speeds. A one-dimension model was used to describe the transient heat and mass transfer in pipes of the gasoline engine. In-cylinder combustion model was calibrated by engine test results. The simulation results showed a good agreement with engine testing results. Simulation and experimental research showed the volumetric efficiency and torque were low from 2500rpm to 3500rpm. Some parametrical study was presented for performance improvement of intermediate speeds, including changing induction-pipe length and putting off multiple camshafts shift.
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