Search Results

During the last several years, significant efforts have been directed toward the development of ultra-clean, gasoline-powered vehicles in the automotive industry. With the coming of increasingly stringent emissions legislation, this development is more critical now than ever before. This has lead to an increase in the technical information available. Advanced Developments in Ultra-Clean Gasoline-Powered Vehicles provides the reader with technical information including a description of fundamental processes, insight on technical issues, key trends, and future R&D directions.

Online combustion efficiency optimization in a variable-valve-timing (VVT) gasoline engine requires the real-time knowledge of in-cylinder pressure and its various derivatives. The in-cylinder pressure measurements, however, are still inapplicable to current light duty vehicles due to the high cost of fast pressure sensors. In this paper, an effective combustion model is developed to provide online prediction of crank-angle resolved (CAR) in-cylinder pressure evolution given five representative initial states at intake valve closing (IVC). The prediction of the combustion pressure is made by incorporating mean-value mass/energy flow models with the first law thermodynamics. To achieve real-time calculation for end-use engines, this paper improves the validity region of the existing mass/energy flow models while preserving their simplicity.

Improving catalyst light-off characteristics during cold start and reducing engine-out (more accurately converter-in) emissions prior to catalyst light-off have been regarded as the keys to meeting future stringent emissions regulations. Many technologies and control strategies have been proposed, and some of them have already been incorporated into production, to address these issues. Among these, secondary air injection received a lot of attention. This study was initiated to investigate the thermal and chemical processes associated with secondary air injection inside the exhaust system in order to maximize the simultaneous benefit of improving catalyst light-off performance and reducing converter-in emissions. The effects of several design and operating parameters such as secondary air injection location, exhaust manifold design, spark timing, engine enrichment level, and secondary air flow rate were carefully examined.

Based on high EGR rate, the low temperature combustion (LTC) has been studied widely, of which the application range is more extensive than the homogeneous charge compression ignition (HCCI) and premixed charge compression ignition (PCCI). As the high EGR rate would influence the condition of intake charge, it would also affect the combustion process and the HC emissions, thus the combustion stability of LTC would be lower than tradition diesel combustion. In this study, an ion current detecting technology was employed to explore the ion current at different EGR rates. Meanwhile, the combustion parameters were also investigated, which included the in-cylinder pressure and heat release rate. The CA50 and CAI50 were adopted as the phases of combustion and ion current, which respectively represented the crank angle of mid-point for the integrated heat release and integrated ion current. Then the correlation between CA50 and CAI50 was analysed.

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.

Extensive experimental and numerical investigations with respect to mass balance unit (MBU) were reported to improve the vibration and acoustic performance for inline 4-cylinder engine due to unbalanced inherent secondary order inertial forces. Design of gear-driven MBU with two parallel shafts and two gear pairs which was positioned beneath the crankshaft would be described in the paper. For the sake of compact package and reliable design, the driving gear ring of the system was shrink fitted onto the crankweb, and issues such as lubrication, strength, assembly were taken into account during design process. As a result, 93.66% of 2nd order mass force balance was achieved and2nd vibration level of engine was decreased remarkably. However, acoustical behavior was deteriorated due to gear impact and rattle at the engagement. Extra efforts were paid to solve the unpleasant noise through internal and external excitation optimizations.

A strategy to facilitate the mixture preparation process in PFI engines is to delay the Intake Valve Opening (IVO) by shifting the cam phasing so that the cylinder pressure is sub-atmospheric when the valve opens. The physics of the effect are discussed in terms of the pressure differential between the manifold and the cylinder, and the resulting flow and charge temperature history. The effect was evaluated by measuring the equivalence ratio of the trapped charge and the exhaust HC emissions in the first cycle of cranking in a 2.4L engine. When the IVO timing was changed from 18° BTDC to 21° ATDC, the in-cylinder fuel equivalence ratio increased by approximately 10%. This increase was attributed mainly to the enrichment of the charge by displacing the leaner mixture at the top of the cylinder in the period between BDC and IVC. The exhaust HC, however, increased by 40%. No conclusive explanation was established for this increase in HC emissions.

Intake volumetric efficiency (VE) of a spark-ignition engine varies with valve timings, engine speeds, and manifold air loads. The existing approaches to reveal the underlying effects of these VE factors on instant valve flows remain complicated and expensive. In an effort to develop an applicable approach to analyze the detail valve flows, a naturally aspirated production engine with dual independent VVT was dynamometer-tested with fast in-cylinder pressure measurements and slow manifold pressure measurements. Both intake and exhaust valve flow was then reproduced using a new model, DQS model, in crank-angle resolution (CAR). One new flow mechanism, the flow wave subsidence, has been revealed to be one of the major drives of VE changes. We propose a dynamic quasi-steady (DQS) flow model to reproduce the valve flow profile from the measured pressure data. The DQS model features two manifold dynamics and a delay in the use of in-cylinder pressure measurements.

Fuel cell vehicle and battery electric vehicle are two environmentally benign vehicle technology types possibly meeting the zero-emission regulations in the future. The premise is they can achieve parity with conventional vehicle both environmentally and economically. Besides, it is necessary to distinguish which technology is more suitable in China's current and future context. This paper compares their cost-effectiveness for reducing greenhouse gas emissions, examining the life-cycle greenhouse gas emissions of conventional gasoline vehicle, battery electric vehicle and fuel cell vehicle in China's energy context under three different scenarios. The results indicate that under the 500km drive range, fuel cell vehicles are less competitive than battery electric vehicles currently. Fuel cell vehicles generate much more greenhouse gas emissions than battery vehicles and conventional gasoline vehicles.

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.

The homogeneous charge, compression-ignition (HCCI) combustion process has the potential to significantly reduce NOx and particulate emissions, while achieving high thermal efficiency and the capability of operating with a wide variety of fuels. This makes the HCCI engine an attractive technology that can ostensibly provide diesel-like fuel efficiency and very low emissions, which may allow emissions compliance to occur without relying on lean aftertreatment systems.

The new technological revolution is promoting the intelligent upgrade of vehicles. Traditional vehicles are gradually developing into intelligent connected vehicles (ICVs). New features such as autonomous driving, smart cockpits, and Internet of Vehicle of ICVs have brought users safe, comfortable and interesting travel experiences. Vehicle software, containing a wealth of functions and continuously outputting valuable data, has become the core of the definition of vehicle functions. Traditional vehicle hardware has gradually decoupled from software and become standardized, modular and shared resources. At present, the era of Software-Defined Vehicle (SDV) is coming soon, which is bound to bring subversive changes to both vehicle technologies and industrial ecologies. However, the lack of comprehensive understanding and the clear development way of SDV are ubiquitous in all kinds of corporations in vehicle industry. This will make them be caught off guard when SDV really comes.

To meet more stringent emission regulations for diesel engines, diesel particulate filters (DPF) have been widely used for diesel engines. However, the DPF regeneration is a great challenge for fuel economy. In this paper, a mathematical model characterizing the microwave regeneration process of a wall-flow particulate filter is introduced to better understand the process. Based on this model, important parameters such as evolutions of the energy stream densities of microwaves, wall temperature, regeneration efficiency and the pressure drop in the filters, both cordierite and SiC, are investigated. These results can provide an important theoretical guide for optimizing and controlling the microwave regeneration process.

Numerical simulation has been widely used in the engine development process to improve the development quality, especially in the area of in-cylinder flow and fuel evaporation. In this paper, a fuel spray model for a gasoline direct injection (GDI) engine, calibrated against spray visualization in a spray bomb, is developed to characterize the fuel spray atomization, vaporization, and interaction with in-cylinder air flow. With this model, fuel atomization and fuel-air mixing process are thoroughly analyzed at full load operating conditions at both low and high speeds. It is shown that fuel spray at high speed is deflected towards intake side, leading to limited wall wetting, piston wetting, and good vaporization, due to intensive tumble flow and high temperature. The results from the numerical simulation provide important guideline for the development of a GDI engine.

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.

Compared with conventional vehicles, electric vehicles (EVs) offer the benefits of replacing petroleum consumption and reducing air pollutions. However, there have been controversies over greenhouse gas (GHG) emissions of EVs from the life-cycle perspective in China’s coal-dominated power generation context. Besides, it is in doubt whether the cost-effectiveness of EVs in China exceeds other fuel-efficient vehicles considering the high prices. In this study, we compared the life-cycle GHG emissions of existing vehicle models in the market. Afterwards, a cost model is established to compare the total costs of vehicles. Finally, the cost-effectiveness of different vehicle types are compared. It is concluded that the GHG emission intensity of EVs is lower than reference and hybrid vehicles currently and is expected to decrease with the improvement of the power grid.

Automotive safety is always the focus of consumers, the selling point of products, the focus of technology. In order to achieve automatic driving, interconnection with the outside world, human-automatic system interaction, the security connotation of intelligent and connected vehicles (ICV) changes: information security is the basis of its security. Functional safety ensures that the system is operating properly. Behavioral safety guarantees a secure interaction between people and vehicles. Passive security should not be weakened, but should be strengthened based on new constraints. In terms of information safety, the threshold for attacking cloud, pipe, and vehicle information should be raised to ensure that ICV system does not fail due to malicious attacks. The cloud is divided into three cloud platforms according to functions: ICVs private cloud, TSP cloud, public cloud.

Smart vehicles have become an important development direction of the transformation and upgrading of the automotive industry. Highly intelligent smart vehicles can free human drivers from driving tasks, endowing cars with the mobility and instrument properties. Smart cockpits integrate the media for interactions between humans and environments inside and outside cars. This paper has explored the components of smart cockpits, sorted out three development stages of smart cockpits from such three dimensions as man, car and environment, analyzed the characteristics of the second development stage (Stage 2.0), and illustrated the necessity of the competition between smartphones and head units at the second stage. Based on the comparison of merits and demerits between smartphones and head units, this paper has proposed three principles for an ideal division of duties of smartphones and head units.

Hybrid electric vehicle (HEV) is regarded as an important technology in solving the energy and environment crisis. In this paper, the HEV technology applied in passenger cars by major automotive OEMs such as Toyota, Honda, GM, Ford, Volkswagen, BMW are investigated. The configuration diagrams for each OEM are presented. Based on the architecture analysis, a classification is done according to similar structures and performances. Furthermore, a cost estimation methodology for HEV is presented based on the preliminary tear-down research done by Environment Protection Agency (EPA). Meanwhile, the logarithmic relationship between fuel consumption (FC) reduction and degree of hybridization (DOH) is discovered by investigating 30 different hybrid cars. Combining the cost estimation and relation between FC&DOH, the hybridization cost for cars to meet the FC regulations can be calculated.

Dr. Fuquan (Frank) Zhao and experts in the field address a broad spectrum of key research and development issues in the rapidly progressing area of near-zero-emission gasoline-powered vehicles. Written in response to the increasingly stringent emissions legislation, this book provides the reader with a concise introduction to technology developments in near-zero-emission gasoline-powered vehicles. The material reflects global technical initiatives within the automotive and research communities. In all, this book contains more than 450 pages, with nearly 200 descriptive diagrams and/or images. It will serve as a valuable desk reference and provide the basics for those who are interested in understanding this advancing technology.