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Technical Paper

New CEC Gasoline Direct Injection Fuels Test – Comparison of Deposits and Spray Performance from New and Used injectors.

2019-11-21
2019-28-2392
The use of deposit control additives in European market gasoline is well documented for maintaining high levels of engine cleanliness and subsequent sustained fuel and emissions performance. Co-ordinating European Council (CEC) industry fuels tests have played a crucial role in helping to drive market relevant, effective and low-cost deposit control additives into European market fuels. Until now, there has not been a Gasoline Direct Injection engine test available to fuel marketers in any market globally. However, a new CEC engine test is currently being developed to address that gap. Based on an in-house VW injector coking test, it shows promise for becoming a useful tool with which to develop and measure the performance of deposit control additives. A key requirement of industry tests should be to replicate issues seen in consumer vehicles, thereby providing a platform for relevant solutions.
Technical Paper

A Novel Three Steps Composited Parameter Matching Method of an Electromagnetic Regenerative Suspension System

2019-04-02
2019-01-0173
The electromagnetic regenerative suspension has attracted much attention recently due to its potential to improve ride comfort and handling stability, at the same time recover kinetic energy which is typically dissipated in traditional shock absorbers. The key components of a ball-screw regenerative suspension system are a motor, a ball screw and a nut. For this kind of regenerative suspension, its damping character is determined by the motor's torque-speed capacity, which is different from the damping character of the traditional shock absorber. Therefore, it is necessary to establish a systematic approach for the parameter matching of ball-screw regenerative suspension, so that the damping character provided by it can ensure ride comfort and handling stability. In this paper, a 2-DOF quarter vehicle simulation model with regenerative suspension is constructed. The effects of the inertia force on ride comfort and handling stability are analyzed.
Technical Paper

Attitude Control of the Vehicle with Six In-Wheel Drive and Adaptive Hydro Pneumatic Suspensions

2019-04-02
2019-01-0456
The ability of actively adjusting attitude provides a great advantage for those vehicles used in special environments such as off-road environment with extreme terrains and obstacles. It can improve vehicles’ stability and performance. This paper proposes an attitude control system for realizing the active attitude adjustment and vehicle motion control in the same time. The study is based on a vehicle with six wheel independent drive and six independent suspensions (6WIDIS), which is a kind of unmanned vehicle with six in-wheel drives and six independent hydro pneumatic suspensions. With the hydro- pneumatic suspensions, the vehicle’s attitude can be actively adjusted. This paper develops a centralized- distributed control strategy with attitude information obtained by multi-sensor fusion, which can coordinate the complex relationship among the six wheels and suspensions. The attitude control system consists of three parts.
Technical Paper

Full Protection Scheme and Energy Optimization Management of the Battery in Internal Combustion Engine Vehicles Based on Power Partitioning Model

2019-04-02
2019-01-1205
As the only energy storage component in the internal combustion engine vehicles (ICEVs), the battery is lack of comprehensive supervision and effective protection. Excessive discharge or aging cannot be detected and dealt with, which may lead to damage of the battery, even startup failure of the vehicle. In this paper, a full protection and optimization management scheme of the battery is proposed, to achieve comprehensive protection of the battery and energy optimization. Firstly, power partitioning model of the battery is established to reveal the battery characteristics in different states, which divides the battery into several function zones. Then, based on the power partitioning model, over discharge protection and graded overcurrent protection method are proposed, to achieve full protection of the battery. Thirdly, energy optimization management strategy based on generator’s multimode operation is introduced.
Technical Paper

Costs, Benefits and Range: Application of Lightweight Technology in Electric Vehicles

2019-04-02
2019-01-0724
The lightweight technology takes an important role in electric vehicle(EV) energy conservation domain, as lighter vehicle means less energy consumed under same condition. In this paper, the typical energy requirement in an NEDC cycle is investigated, and the relationship between lightweight rate and energy consumption reduction effectiveness is given. The benefit of lightweight to EV come from the less battery cost because of less energy requirement. For EVs, with less battery cost, a certain lightweight rate can be obtained with less total cost. On the other hand, if lightweight rate is very high, the battery cost won't be able to cover the lightweight cost. Besides, the relationship between driving range and battery capacity is discussed in this paper. It is found that there is a limitation of EV driving range, which is determined by the battery energy density.
Technical Paper

A Topological Map-Based Path Coordination Strategy for Autonomous Parking

2019-04-02
2019-01-0691
This paper proposed a path coordination strategy for autonomous parking based on independently designed parking lot topological map. The strategy merges two types of paths at the three stages of path planning, to determinate mode switching timing between low-speed automated driving and automated parking. Firstly, based on the principle that parking spaces should be parallel or vertical to a corresponding path, a topological parking lot map is designed by using the point cloud data collected by LiDAR sensor. This map is consist of road node coordinates, adjacent matrix and parking space information. Secondly, the direction and lateral distance of the parking space to the last node of global path are used to decide parking type and direction at parking planning stage. Finally, the parking space node is used to connect global path and parking path at path coordination stage.
Technical Paper

Fuel Economy Regulations and Technology Roadmaps of China and the US: Comparison and Outlook

2018-09-10
2018-01-1826
In order to address the increasing energy and environmental concerns, China and the US both launched the fuel economy regulations and aim to push the development of technology. In this study, the stringency of CAFC and CAFE regulations and the technology development of two countries are compared. Besides, the optimal technology pathways of America and automakers for the compliance of CAFE regulations are calculated based on the modified VOLPE model, and the results are used as reference for China. The results indicate that the annual regulation improvement rates of China is higher than America and the AIR of China 2015-2020 regulation reaches 6.2% and is the most stringent phase in 10 years from 2015 to 2025. From the perspective of technology, there are still big gaps between China and the US in the applications of advanced fuel saving technologies.
Technical Paper

An Optical Study on the Combustion of Gasoline/PODEn Blends in a Constant Volume Vessel

2018-09-10
2018-01-1748
Polyoxymethylene dimethyl ethers (PODEn) have high cetane number, high oxygen content and high volatility, therefore can be added to gasoline to optimize the performance and soot emission of Gasoline Compression Ignition (GCI) combustion. High speed imaging was used to investigate the spray and combustion process of gasoline/PODEn blends (PODEn volume fraction 0%-30%) under various ambient conditions and injection strategies in a constant volume vessel. Results showed that with an increase of PODEn proportion from 10% to 30%, liquid-phase penetration of the spray increased slightly, ignition delay decreased from 3.8 ms to 2.0 ms and flame lift off length decreased 29.4%, causing a significant increase of the flame luminance. For blends with 20% PODEn, when ambient temperature decreased from 893 K to 823 K, the ignition delay increased 1.3 ms and the flame luminance got lower.
Technical Paper

Effect of Single and Double-Deck Pre-Chamber Designs to the Combustion Characteristics of Premixed CH4 /Air

2018-09-10
2018-01-1688
An experiment was carried out to investigate the effect of single and double-deck pre-chamber on the combustion characteristics of premixed CH4/air in a constant volume vessel using schlieren method. A special design was proposed for the visualization of the pre-chamber. Combustion with different initial temperatures (300 K, 400 K, 500 K) were observed at stoichiometric ratio to lean-burn limit. Although single-deck pre-chamber has advantages over double-deck pre-chamber in both initial flame development duration and main combustion duration, the latter could extend the lean-burn limit by up to 0.3 and promote the stability of ignition. It is also found that extensive distribution of active species in main chamber before ignition can accelerate speed of flame propagation enormously.
Technical Paper

Structural Designs for Electric Vehicle Battery Pack against Ground Impact

2018-04-03
2018-01-1438
Ground impact caused by road debris can result in very severe fire accident of Electric Vehicles (EV). In order to study the ground impact accidents, a Finite Element model of the battery pack structure is carefully set up according to the practical designs of EVs. Based on this model, the sequence of the deformation process is studied, and the contribution of each component is clarified. Subsequently, four designs, including three enhanced shield plates and one enhanced housing box, are investigated. Results show that the BRAS (Blast Resistant Adaptive Sandwich) shield plate is the most effective structure to decrease the deformation of the battery cells. Compared with the baseline case, which adopts a 6.35-mm-thick aluminum sheet as the shield plate, the BRAS can reduce the shortening of cells by more than 50%. Another type of sandwich structure, the NavTruss, can also improve the safety of battery pack, but not as effectively as the BRAS.
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

Recycling-Based Reduction of Energy Consumption and Carbon Emission of China’s Electric Vehicles: Overview and Policy Analysis

2018-04-03
2018-01-0659
Electric vehicles maintain the fastest development in China and undertake the responsibility of optimizing energy consumption and carbon emission in the transportation field. However, from the entire life cycle point of view, although electric vehicles have a certain degree of energy consumption and carbon emission reduction in the use phase, they cause extra energy consumption and carbon emission in the manufacturing phase, which weakens the due environmental benefits to some extent. The recycling of electric vehicles can effectively address the issue and indirectly reduce the energy consumption and carbon emission in the manufacturing phase. China is setting up the recycling system and strengthening regulation force to achieve proper energy consumption and carbon emission reduction benefits of electric vehicles. Under the current electric vehicle recycling technologies, China can reduce about 34% of carbon emission in electric vehicle manufacturing phase.
Technical Paper

An Innovative Design of In-Tire Energy Harvester for the Power Supply of Tire Sensors

2018-04-03
2018-01-1115
With the development of intelligent vehicle and active vehicle safety systems, the demand of sensors is increasing, especially in-tire sensors. Tire parameters are essential for vehicle dynamic control, including tire pressure, tire temperature, slip angle, longitudinal force, etc.. The diversification and growth of in-tire sensors require adequate power supply. Traditionally, embedded batteries are used to power sensors in tire, however, they must be replaced periodically because of the limited energy storage. The power limitation of the batteries would reduce the real-time data transmission frequency and deteriorate the vehicle safety. Heightened interest focuses on generating power through energy harvesting systems in replace of the batteries. Current in-tire energy harvesting devices include piezoelectric, electromagnetic, electrostatic and electromechanical mechanism, whose energy sources include tire deformations, vibrations and rotations.
Journal Article

Energy Harvesting in Tire: State-of-the-Art and Challenges

2018-04-03
2018-01-1119
Although energy harvesting systems are extensively used in different fields, studies on the application of energy harvesters embedded in tires for vehicle control are rare and mostly focus on solving power supply problems of tire pressure sensors. Sensors are traditionally powered by an embedded battery, which must be replaced periodically because of its limited energy storage. Heightened interest in vehicle safety is expected to drive increased design and manufacture of in-tire sensors, which in turn, translates to rising demand for power generation in tires. These challenges emphasize the need to investigate the substitution of batteries and in-tire energy harvesting systems. Current in-tire energy harvesting methods involve piezoelectric, electromagnetic, and electrostatic power generation, whose energy sources include tire vibrations, deformations, and rotations. Piezoelectric harvesters are generally compact but operate for short durations.
Journal Article

Characterization of Metal Foil in Anisotropic Fracture Behavior with Dynamic Tests

2018-04-03
2018-01-0108
Metal foil is a widely used material in the automobile industry, which not only is the honeycomb barrier material but is also used as current collectors in Li-ion batteries. Plenty of studies proved that the mechanical property of the metal foil is quite different from that of the metal sheet because of the size effect on microscopic scale, as the metal foil shows a larger fracture stress and a lower ductility than the metal sheet. Meanwhile, the fracture behavior and accurate constitutive model of the metal foil with the consideration of the strain rate effect are widely concerned in further studies of battery safety and the honeycomb. This article conducted experiments on 8011H18 aluminum foil, aiming to explore the quasi-static and dynamic tension testing method and the anisotropic mechanical behavior of the very thin foil. Two metal foil dog-bone specimens and three types of notched specimens were tested with a strain rate ranging from 2 × 10−4/s to 40/s and various stress states.
Technical Paper

Characterizing Propane Flash Boiling Spray from Multi-Hole GDI Injector

2018-04-03
2018-01-0278
In this research, propane flash boiling sprays discharged from a five-hole gasoline direct injector were studied in a constant volume vessel. The fuel temperature (Tfuel) ranged from 30 °C to 90 °C, and the ambient pressure (Pamb) varied from 0.05 bar to 11.0 bar. Different flash boiling spray behavior compared to that under sub-atmospheric conditions was found at high Pamb. Specifically, at the sub-atmospheric pressures, the individual flashing jets merged into one single jet due to the strong spray collapse. In contrast, at Pamb above 3.0 bar and Tfuel above 50 °C, the spray collapse was mitigated and the flashing jets were separated from each other. Further analyses revealed that the mitigation of spray collapse at high Pamb was ascribed to the suppression of jet expansion. In addition, it was found that the spray structure was much different at similar Rp, indicating that Rp lacked the generality in describing the structure of flash boiling sprays.
Technical Paper

Piecewise Affine-Based Shared Steering Torque Control Scheme for Cooperative Path-Tracking: A Game-Theoretic Approach

2018-04-03
2018-01-0606
The new concept of “human-machine shared control” provides an amazing thinking to enhance driving safety, which has been attracted a great deal of research effort in recent years. However, little attention has been paid to the nonlinearity of the shared control system brought by the tire, which significantly influences the control performance under extreme driving conditions. This paper presents a novel shared steering torque control scheme to model the human-machine steering torque interaction near the vehicle’s handling limit, where both driver and driver assistance system (DAS) are exerting steering torque to maneuver the vehicle. A six-order driver-vehicle dynamic system is presented to elaborate the relationship between steering torque input and vehicle lateral motion response. Particularly, we use a piecewise affine (PWA) method to approximate the tire nonlinearity.
Technical Paper

Fuel Economy Analysis of Periodic Cruise Control Strategies for Power-Split HEVs at Medium and Low Speed

2018-04-03
2018-01-0871
Hybridization of vehicles is considered as the most promising technology for automakers and researchers, facing the challenge of optimizing both the fuel economy and emission of the road transport. Extensive studies have been performed on power-split hybrid electric vehicles (PS-HEVs). Despite of the fact that their excellent fuel economy performance in city driving conditions has been witnessed, a bottle neck for further improving the fuel economy of PS-HEVs has been encountered due to the inherent engine-generator-motor power circulation of the power-split system under medium-low speed cruising scenarios. Due to the special mechanical constraints of the power-split device (PSD), the conventional periodic cruising strategy like Pulse and Glide cannot be applied to PS-HEVs directly.
Technical Paper

Energetic Macroscopic Representation Based Energy Management Strategy for Hybrid Electric Vehicle Taking into Account Demand Power Optimization

2017-10-08
2017-01-2208
To further explore the potential of fuel economy for hybrid electric vehicle (HEV), a methodology of demand power optimization is proposed. The fuel consumption depends not only on the EMS, but also on the way to operate vehicle. A control strategy to adjust driver’s demand before power splitting is necessary. To get accurate and reliable control strategy, two aspects are the most important. First, a rigorous and organized modeling approach is a base to describe complicated powertrain system of HEV. The energetic macroscopic representation (EMR) is a graphical synthetic description of electromechanical conversion system based on energy flow. A powertrain architecture of HEV is described explicitly via the EMR. Second, the effectiveness of EMS and the reasonability of driving operations are vital.
Technical Paper

The engaging process model of sleeve and teeth ring with a precise, continuous and nonlinear damping impact model in mechanical transmissions

2017-10-08
2017-01-2443
During the engaging process of sleeve and teeth ring in mechanical transmissions, their rotational speed and position differences cause multiple engaging ways and trajectories, and casual impacts between them will delay the engaging process and cause a long power off time for a gear shift. In order to reveal the engaging mechanism of the sleeve and the teeth ring, it is essential to build a high-fidelity model to cover all of their engaging ways and capture their speed changes for an impact. In this work, our contribution is that their impact process is modeled as a precise, continuous and nonlinear damping model, and then a hybrid automaton model is built to connect the system dynamics in different mechanical coupling relationships.
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