Refine Your Search

Topic

Search Results

Technical Paper

Instantaneous Optimization Energy Management for Extended-Range Electric Vehicle Based on Minimum Loss Power Algorithm

2013-09-08
2013-24-0073
Most of the existing energy management strategies for Extended-Range Electric Vehicles (E-REVs) are heuristic, which restricts coordination between the battery and the Range Extender. This paper presents an instantaneous optimization energy management strategy based on the Minimum Loss Power Algorithm (MLPA) for a fuel cell E-REV. An instantaneous loss power function of power train system is constructed by considering the charge and discharge efficiency of the battery, together with the working efficiency of the fuel cell Range Extender. The battery working mode and operating points of the fuel cell Range Extender are decided by an instantaneous optimization module (an artificial neural network) that aims to minimize the loss power function at each time step.
Technical Paper

Improvement on Energy Efficiency of the Spark Ignition System

2017-03-28
2017-01-0678
Future clean combustion engines tend to increase the cylinder charge to achieve better fuel economy and lower exhaust emissions. The increase of the cylinder charge is often associated with either excessive air admission or exhaust gas recirculation, which leads to unfavorable ignition conditions at the ignition point. Advanced ignition methods and systems have progressed rapidly in recent years in order to suffice the current and future engine development, and a simple increase of energy of the inductive ignition system does not often provide the desired results from a cost-benefit point of view. Proper design of the ignition system circuit is required to achieve certain spark performances.
Technical Paper

Experimental and Numerical Study on Combustion Characteristics of Hydrogen-Argon Jet in a Hot Vitiated Co-flow

2018-04-03
2018-01-1139
This paper presents a study of the Hydrogen/Argon lifted flames in a hot vitiated co-flow. The effects of the dilution of argon in central fuel, the volume fraction of argon in the central fuel, co-flow temperature and the velocity of the central jet on the flame lift-off length were studied, and the numerical simulation with PDF model were analyzed as well. The results could provide theoretical supports for the research of the hydrogen fueled argon cycle engine which is a potential way not only to increase the indicated thermal efficiency of internal combustion engine but also realize the zero emission. The result shows that at the same boundary condition the central jet of H2+Ar has a lower lift-off length than the central jet of H2+N2. By the numerical simulation, the jet flame of H2+Ar has a higher maximum temperature and maximum OH concentration. It indicated that the dilution of argon could promote the combustion reaction.
Technical Paper

Development of Hardware and Software for On-Board Hydrogen System

2019-04-02
2019-01-0377
The fuel cell engine is considered to be the ultimate technical direction for the development of vehicle power. The on-board hydrogen supply system is important in fuel cell system. However, the on-board hydrogen supply system is diversified, and the management is mostly integrated in the engine controller. Thus, the fuel cell engine controller is excessive coupled with design of on-board hydrogen supply system. In order to improve the portability and compatibility of the fuel cell engine controller, an independent controller of the on-board hydrogen supply system is designed. Meanwhile, the hardware and software are developed to control 35Mpa gaseous hydrogen storage system. After being tested in a high-pressure environment, the controller can detect temperature, pressure and ambient hydrogen concentration of the hydrogen supply system. Simultaneously, it can drive and control the hydrogen cylinder valve.
Technical Paper

DC/DC Modeling and Current Harmonic Analysis in Fuel Cell Hybrid Power System

2019-04-02
2019-01-0375
Fuel cells directly convert the energy stored in hydrogen into electrical energy through an electrochemical reaction, and the only reaction product is water, which can improve the energy efficiency and reduce the pollution caused by fossil fuels. The fuel cell hybrid power system used in vehicles usually consists of a fuel cell stack and a power battery module, and the DC/DC converter is the key component to connect them together. The current ripples caused by the system have been confirmed to have detrimental effects on the fuel cell’s reliability and lifespan. In addition, it is one of the key factors that reduce the system efficiency. So, it is necessary to analyze the current ripple in the system and maintain it at a low level. In this paper, a brief review on the different kinds of converters used in vehicles has been made. Then, with the help of MATLAB/SIMULINK, a simulation model of the hybrid power system based on 4-phase interleaved parallel topology is established.
Technical Paper

Experiments of Methanol-Gasoline SI Engine Performance and Simulation of Flexible Fuel Characteristic Field

2018-04-03
2018-01-0927
Due to the oil crisis and the requirements of energy saving and emission reduction, the research of alternative energy sources for sustainable development has made good progress. Methanol has proven to be a very suitable alternative clean fuel. Compared with gasoline, methanol has a wide range of source and the higher oxygen content and octane number and combustion efficiency, which are beneficial for the engine performance. The effect of different proportions of methanol-gasoline mixed fuel on the performance of SI engine was studied experimentally (lower proportion and higher proportion). It was found that the engine power performance, fuel economy and exhaust emissions were related to the methanol ratio under different operating conditions. In order to adapt to different operating conditions to improve the performance of methanol-gasoline engine, an on-board flexible fuel mixed system was proposed.
Technical Paper

Vibration Analysis of Series-parallel Hybrid Powertrain System under Typical Working Condition and Modes

2018-04-03
2018-01-1291
Powertrain system of series-parallel hybrid vehicle contains multiple excitation sources like engine, motor and generator. The reduction of noise and vibration is quite difficult during multiplex working modes or the switch of modes. Aiming at Series-parallel hybrid powertrain system which contains engine, motor and planetary gear subsystems, this paper considered a typical working condition which is based on the power control strategy and established the torsional vibration mechanical model of hybrid powertrain system. The inherent characteristics and transient vibration response of the electric mode, hybrid mode and parking charging mode were studied and it was discovered that the repetitive frequency of the powertrain system under the three working modes is the same which is only related to inertia and meshing stiffness of planetary gear system. The non-repetitive frequency and corresponding vibration modes under the electric mode and parking charging mode are both close.
Technical Paper

Simulation Investigation of Working Process and Emissions on GDI Engine Fueled with Hydrous Ethanol Gasoline Blends

2019-04-02
2019-01-0219
Compared with ordinary gasoline, using ethanol gasoline blends as fuel of Internal Combustion Engine is beneficial for the performance of power, economy and emission of engine. However, the fuel ethanol blended in ethanol gasoline blends currently is usually anhydrous ethanol, which requires dewatering implementer in production process, and the cost is high. Therefore, the production cost can be significantly reduced by replacement of anhydrous ethanol with hydrous ethanol while exerting the advantage of ethanol gasoline blends. In this study, computation fluid dynamics (CFD) software CONVERGE is employed to establish a simulation model of an actual gasoline direct injection (GDI) engine, and investigate the effect of burning hydrous ethanol gasoline blends and different injection strategy on combustion process and emission, and the validity of the model was validated by experiments.
Technical Paper

Experimental Study on Particulate Emission Characteristics of an Urban Bus Equipped with CCRT After-Treatment System Fuelled with Biodiesel Blend

2017-03-28
2017-01-0933
Biodiesel as a renewable energy is becoming increasingly attractive due to the growing scarcity of conventional fossil fuels. Meanwhile, the development of after-treatment technologies for the diesel engine brings new insight concerning emissions especially the particulate matter pollutants. In order to study the coupling effects of biodiesel blend and CCRT (Catalyzed Continuously Regeneration Trap) on the particulate matter emissions, the particulate matter emissions from an urban bus with and without CCRT burning BD0 and BD10 respectively was tested and analyzed using electrical low pressure impactor (ELPI). The operation conditions included steady state conditions and transient conditions. Results showed that the particulate number-size distribution of BD10 and BD0 both had two peaks in nuclei mode and accumulation mode at the conditions of idle, low speed and medium speed while at high speed condition the particulate number-size distribution only had one peak.
Technical Paper

Research on a New Electromagnetic Valve Actuator Based on Voice Coil Motor for Automobile Engines

2017-03-28
2017-01-1070
The electromagnetic valve actuator (EMVA) is considered a technological solution for decoupling between crankshaft and camshaft to improve engine performance, emissions, and fuel efficiency. Conventional EMVA consists of two electromagnets, an armature, and two springs has been proved to have the drawbacks of fixed lift, impact noise, complex control method and large power consumption. This paper proposes a new type of EMVA that uses voice coil motor (VCM) as electromagnetic valve actuator. This new camless valvetrain (VEMA) is characterized by simple structure, flexible controllable and low actuating power. VCM provides an almost flat force versus stroke curve that is very useful for high precision trajectory control to achieve soft landing within simple control algorithm.
Technical Paper

Emergency Steering Evasion Control by Combining the Yaw Moment with Steering Assistance

2018-04-03
2018-01-0818
The coordinated control of stability and steering systems in collision avoidance steering evasion has been widely studied in vehicle active safety area, but the studies are mainly aimed at autonomous vehicle without driver or conventional combustion engine vehicle. This paper focuses on the control of hybrid vehicle integrated with rear hub in emergency steering evasion situation, and considering the driver’s characteristics. First, the mathematics model of vehicle dynamics and driver has been given. Second, based on the planned steering evasion path, the model predictive control method is presented for achieving higher evasion path tracking accuracy under driver’s steering input. The prediction model includes an adaptive preview distance driver model and a vehicle dynamics model to predict the driver input and the vehicle trajectory.
Technical Paper

Fast Prediction of Disc Brake Squeal Uncertainty Based on Perturbation Concept

2018-04-03
2018-01-0677
It is a worldwide technical difficulty to predict brake squeal uncertainty and its propagation regularity due to key parameters’ randomcity. However, as a widely used stochastic finite element method, Monte Carlo Method costs a large amount of time in calculation. It is very important to establish a fast prediction method for brake squeal uncertainty due to key parameters. In this paper, perturbation concept was applied for disc brake squeal uncertainty prediction. Firstly, a simplified, parameterized finite element model of disc brake was established for complex eigenvalues calculation. Then sensitivity analysis of real parts and frequencies of complex eigenvalues to influence parameters was carried out based on the finite element model. A series of second order perturbation polynomial formulas were fitted from the sensitivity analysis results, which were used for calculation of uncertain complex eigenvalues.
Technical Paper

Study on Correlation between After-Treatment Performance and Running Conditions, Exhaust Parameters of Heavy-Duty Diesel Vehicle

2018-04-03
2018-01-0338
The increasingly stringent emission regulations have mandated the use of CCRT (catalyzed continuously regeneration trap) made by upstream DOC (diesel oxidation catalyst) and downstream CDPF (catalyzed diesel particulate filter) for heavy-duty diesel vehicles, which is proved to be the only way that can efficiently control the gaseous and particulate emissions. The performance of after-treatment is greatly influenced by the running conditions of the diesel vehicle and its exhaust parameters, so this paper intended to use grey relational analysis to study the correlation between running conditions (velocity, acceleration, VSP (vehicle specific power)), exhaust parameters (exhaust flow rate, DOC inlet temperature, concentrations of CO, THC, O2 and NOX) and the performance of DOC and CCRT based on chassis dynamometer test. Results showed that the effect of DOC on CO and THC is mainly affected by exhaust flow rate, exhaust temperature and THC concentration.
Technical Paper

Numerical Study of Intake Manifold Water Injection on Characteristics of Combustion and Emissions in a Heavy-Duty Natural Gas Engine

2019-04-02
2019-01-0562
The performances of heavy-duty natural gas engines have been limited by combustion temperature and NOx emissions for a long time. Recently, water injection technology has been widely considered as a technical solution in reducing fuel consumption and emissions simultaneously in both gasoline and diesel engines. This paper focuses on the impacts of intake manifold water injection on characteristics of combustion and emissions in a natural gas heavy-duty engine through numerical methods. A computational model was setup and validated with experimental data of pressure traces in a CFD software coupled with detailed chemical kinetics. The simulation was mainly carried out in low-speed and full-load conditions, and knock level was also measured and calculated by maximum amplitude of pressure oscillations (MAPO).
Technical Paper

Study on Real-World NOx and Particle Emissions of Bus: Influences of VSP and Fuel

2019-04-02
2019-01-1181
In this study, the real-world NOx and particle emissions of buses burning pure diesel fuel (D100), biodiesel fuel with 20% blend ratio (B20) and liquefied natural gas (LNG) were measured with portable emission measurement system (PEMS). The measurement conducted at 6 constant speed, which ranged from 10km/h to 60 km/h at 10km/h intervals, and a period of free driving condition. The relationship between vehicle specific power (VSP) and NOx/particle emissions of each bus were analyzed. The results show that the change rules of NOx, PN and PM emission factors with the increase of VSP were basically the same for the same bus, but for the bus using different fuel, the change rules may change. In VSP bin 0, the vehicles were mostly in idle condition and the emission factors of NOx, PN and PM of three buses were all in a relatively high level. In low VSP interval, which ranged from bin 0 to bin 4, the emissions of three buses first decreased and then increased with the growth of VSP.
Technical Paper

Experiment Studies of Charging Strategy for Lithium-Ion Batteries

2019-04-02
2019-01-0792
Regarding the lithium-ion batteries used in the electric vehicle, charging time and charging efficiency are the concern of the public. In this paper, a lot of experiments were conducted to investigate the common charging strategies, including the CC-CV (constant current-constant voltage) charging and the pulse current charging, for the LiFePO4 batteries, which are still widely used in commercial vehicles. Charging temperature and the charging current in the CC phase are the main influence factors to be studied for the CC-CV charging strategy, and the contribution of the CC phase and CV phase to the whole charging is analyzed from three aspects, including the time percent, charging energy efficiency and the capacity of battery at different temperatures and charging current.
Technical Paper

Pressure Estimation Algorithms in Decoupled Electro-Hydraulic Brake System Considering the Friction and Pressure-Position Relationship

2019-04-02
2019-01-0438
This paper presents several pressure estimation algorithms (PEAs) for a decoupled electro-hydraulic brake system (EHB), which is driven by an electric motor + reduction gear. Most of the pressure control solutions are based on standard pressure-based feedback control, requiring a pressure signal. Although the pressure sensor can produce the pressure feedback signal, it will increase cost and enlarge installation space. The rotation angle of electric motor is available by the built-in sensor, so the pressure can be estimated by using the rotation angle. Considering the typical nonlinearities (i.e. friction, pressure-position relationship) and uncertainties (i.e. disturbance caused by friction model), the estimation-oriented model is established. The LuGre model is selected to describe the friction, and the pressure-position relationship is fitted by a quadratic polynomial.
Technical Paper

Characteristics of Transient NO Emissions Based on the First Firing Cycle Analysis of Cold-Start

2006-04-03
2006-01-1050
The First Firing Cycle (FFC) is very important at cold-start. Misfiring of the first firing cycle can lead to significant HC emissions and affect the subsequent cycles. This paper presents an investigation of characteristics of transient NO emissions in a small LPG SI engine with electronic gaseous injection system. To determine the optimal excess air coefficient ( λ=[A/F]/[A/F]stoic) of the first firing cycle, the emission of instantaneous NO was proposed as a useful criterion to judge if the combustion is occurred or not. A fast response NO detector- Cambustion fNOx400, based on the chemiluminescence's (CLD) method, has been employed to measure continuous, transient emissions of NO during the first firing cycle in the exhaust port of the engine. At the same time, the transient cylinder pressure, instantaneous crankshaft speed of the engine and engine-out HC emissions were measured and recorded.
Technical Paper

Design and Simulation of Serial Hybrid Electric Moped Powertrain

2008-06-23
2008-01-1567
According to the requirements of two-wheel vehicle's future market and the characteristic of urban road conditions in China, the advantages and disadvantages of three basic configurations for the Hybrid Electric Vehicle are compared, finally, the serial hybrid configuration is chosen to be applied to hybrid Electric Moped solution. The selection principle of main components of this hybrid powertrain system includes ICE, generator, battery and hub motor, and the optimal match for performance parameters of these components are introduced in this paper. Then, a hybrid system model is established based on AVL-CRUISE. The simulations of fuel efficiency and exhaust emissions for both serial hybrid moped and conventional motorcycle is offered.
Technical Paper

Study on EP Energy-Saving Vehicle

2008-06-23
2008-01-1775
The price of fossil fuels and the increasing inexorable energy crisis have become vital issues for everyone. Tongji University EconoPower Racing Team was established to participate in the “Honda EconoPower Cup” annually. Every contestant in the competition must finish a certain distance in the fixed time, with the gasoline supplied by the committee. After that the committee will measure the fuel consumption of every team and calculate the distance per liter fuel (the farther the better) to determine the champion. In order to enhance the EP vehicle's achievement we've made some improvements, such as framework, body, engine's optimization and so on. In this passage we mainly state some details of our research approaches in framework, steering, transmission, shape and driving strategy. The main technologies were: friction reduction, lightweight, enhancement of power train efficiency, tire selection and driving strategy.
X