E6控制系统在天然气发动机上的应用

为了验证E6控制系统的配机效果,并使4020CT型天然气发动机的性能达到设计要求,使用E6控制系统对该发动机进行各工况运行条件的优化标定。E6控制系统使用空燃比闭环控制策略,能够使发动机保持运行在设定的各工况最佳运行条件下。通过E6控制系统的应用试验,完成了发动机性能参数的标定和优化,以及试验数据的采集和分析。试验结果表明,4020CT型天然气发动机的性能特性、排放指标等均达到设计要求。这说明E6控制系统标定效果较佳,同时,为E6控制系统的推广应用奠定了基础。     

低黏度0W-16汽油机油减摩性能研究

目的 研究低黏度0W-16机油的减摩性能。方法 选取3种减摩剂MoDTC、GMO和油酸酰胺，分别按一定比例加入到0W-16基础油中，获得单剂油样，并选取2种0W-16全配方机油（A-1油和A-2油），利用SRV-IV试验机测试润滑油样的减摩性能和极压性能，利用傅立叶红外光谱仪和油料元素光谱分析仪分析机油油样结构，并利用3D光学表面轮廓仪表征缸套块磨痕形貌。结果 对于单剂油样，0W-16基础油分别加入MoDTC、GMO和油酸酰胺后，平均摩擦系数由0.198分别减小到0.088~0.116、0.167~0.178和0.179~0.194，缸套块磨痕平均深度由3.59 mm分别减小到0.44~0.52 mm、2.11~2.24 mm和3.19~3.44 mm。对于0W-16全配方机油，在摩擦润滑试验低温区，A-1油比A-2油摩擦系数低，随着温度升高，A-1油和A-2油的摩擦系数进一步减小；摩擦润滑试验后，A-1油和A-2油的缸套块磨痕平均深度分别为0.13 mm和0.18 mm。在极压试验中，A-1油和A-2油的极压值分别为1500 N和900 N。结论 在0W-16基础油中分别加入3种减摩剂后，MoDTC的减摩和抗磨作用最好，油酸酰胺的减摩和抗磨作用最差。对于0W-16全配方机油，在摩擦润滑试验低温区，A-1油中的无灰减摩剂和MoDTC产生协同作用，表现出更低的摩擦系数；随着温度升高，A-1油和A-2油中的ZDDP与MoDTC产生协同作用，进一步降低摩擦系数。在极压试验中，A-1油中的ZDDP与其他添加剂产生协同作用，表现出更大的极压值。添加剂之间的协同作用对油品节能性能产生重要影响。     

Concept design of a novel reformer producing hydrogen for internal combustion engines using fuel decomposition method: Performance evaluation of coated monolith suitable for on-board applications

Hydrogen addition effectively reduces the fuel consumption of spark ignition engines. We propose a new on-board reformer that produces hydrogen at high concentrations and enables multi-mode operations. For the proposed reformer, we employ a catalytic fuel decomposition reaction via a commercial NiO–CaAl₂O₄ catalyst. We explore the physical and chemical aspects of the reforming process using a fixed bed micro-reactor operating at temperatures of 550–700 °C. During reduction, methane is decomposed to form hydrogen and carbon. Carbon formation is critical to hydrogen production, and free space for carbon growth is essential at low temperatures (≤600 °C). We define a new accumulated conversion ratio that quantitatively measures highly transient catalytic decomposition. The free space of the coated monolith clearly aided low-temperature decomposition with negligible pressure drop. The coated substrate is therefore suitable for on-board applications considering that our reformer concept also utilizes the catalytic fuel decomposition reaction.     

基于双向耦合的东安513型发动机整机多物理场研究

以东安513型汽油发动机整机为例,基于ANSYS有限元分析软件对其进行流体场、瞬态温度场以及瞬态结构场的多物理场双向耦合研究,实现了对发动机实际工况下的有限元分析。研究了发动机整机在实际工况下的受力以及密封情况,并对现有发动机组合结构存在的密封缺陷进行优化调整。文中详细阐述了在分析过程中涉及到的关键技术和要点,并最终获得了发动机整机实际工作状态下的多个结果云图。根据分析结果云图可以发现,发动机在热载荷、螺栓预紧力以及爆破压力的共同影响下,会使整机发生一定的形变,这种变形会影响其工作状况下的密封性能。通过对分析结果的研究,最终选择调整螺栓预紧力的大小和分布来提高发动机密封性能。     

Supersonic driven detonation dynamics for rotating detonation engines

In this paper we present the first exploration of detonation wave propagation dynamics in premixed supersonic flows using a novel rotating detonation engine (RDE) configuration. An RDE with a coupled linear extension, referred to as ρDE, is used to divide detonations traveling radially in the RDE into linearly propagating waves. A tangential propagating wave is directed down a modular tangential linearized extension to the engine for ease of optical diagnostics and hardware configuration investigations. A premixed Mach 2 supersonic linear extension is coupled to the ρDE to investigate the effects of varying crossflow configurations for detonation propagation, particularly the interaction between detonations and supersonic reactive mixtures. Detonation waves are generated at the steady operating frequency of the RDE and visualized using high speed schlieren and broadband OH* chemiluminescence imaging. The stagnation pressure was varied from over- to ideally-expanded supersonic regimes. Experimental analysis of detonation interaction with the supersonic regimes show that the detonation propagates freely in the ideally-expanded regime. Deflagration-to-detonation transition (DDT) occurs in the over-expanded regime. Based on the data collected, the DDT process favors supersonic flow with higher source pressures.     

Effect of natural gas enrichment with hydrogen on combustion characteristics of a dual fuel diesel engine

Environmental benefits are one of the main motivations encouraging the use of natural gas as fuel for internal combustion engines. In addition to the better impact on pollution, natural gas is available in many areas. In this context, the present work investigates the effect of hydrogen addition to natural gas in dual fuel mode, on combustion characteristics improvement, in relation with engine performance. Various hydrogen fractions (10, 20 and 30 by v%) are examined. Results showed that natural gas enrichment with hydrogen leads in general to an improved gaseous fuel combustion, which corresponds to an enhanced heat release rate during gaseous fuel premixed phase, resulting in an increase in the in-cylinder peak pressure, especially at high engine load (4.1 bar at 70% load). The highest cumulative and rate of heat release correspond to 10% Hydrogen addition. The combustion duration of gaseous fuel combustion phase is reduced for all hydrogen blends. Moreover, this technique resulted in better combustion stability. For all hydrogen test blends, COV_IMEP does not exceed 10%. However, no major effect on combustion noise was noticed and the ignition delay was not affected significantly. Regarding performance, an important improvement in energy conversion was obtained with almost all hydrogen blends as a result of improved gaseous fuel combustion. A maximum thermal efficiency of 32.5%, almost similar to the one under diesel operation, and a minimum fuel consumption of 236 g/kWh, are achieved with 10% hydrogen enrichment at 70% engine load.     

Effect of diethyl ether blended with neem oil methyl esters in CI engine

Vegetable oils are now considered to be a potential alternative that can be used in place of partial or total substitution of diesel fuels. In this study, we used diethyl ether as an oxygenated additive to investigate the possible use of higher percentages of biodiesel in an unmodified diesel engine. Neem oil was selected for biodiesel production. The tests were performed at a steady-state condition in a single-cylinder constant speed DI diesel engine. The combustion process involved in diesel engine would be improved and the particulate matter would be reduced if these biodiesels are blended. An experimental investigation is carried out to establish the emission characteristics of a direct injection diesel engine using diethyl ether as additive in Neat Neem oil Biodiesel. Emissions of hydro carbon oxides of nitrogen and carbon monoxide significantly reduced by adding diethyl ether into neem oil biodiesel at 10% and 20% on volume basis.     

Boccia game simulator: Serious game adapted for people with disabilities

Integration in the world of sport is one way for individuals with disabilities or motor disorders to feel more socially integrated, independent, and confident. Boccia is a Paralympic sport, which is increasingly getting more attention around the world. These facts have contributed to the objectives of this work. Including it in the serious games category enables to develop and rehabilitate the cognitive capabilities. The main focus was BC3 classification athletes (users with limited motor characteristics that require the use of an assistive device—a ramp, in this case). This paper describes a realistic Boccia game simulator adapted for people with disabilities that integrates a set of features that includes real physics and social features. These features can be used to enhance the interest of nonpractitioners of the sport and to improve the training conditions. The official Boccia regulation was added to the design of the simulator. The usability and approximation to the reality of the simulator were tested and validated based on the tests performed and data collected via a survey of users with no motor or psychological disorders. Realism and usability rating was almost excellent, and good results were achieved at the assessment of the game experience.     

Contemporary challenges of soot build-up in IC engine and their tribological implications

Confronted with the contemporary challenges of maximising energy efficiency with minimal impact on the environment, the automotive industry has developed various technologies to tackle them. Most of these technologies, however, have wider implications on the tribological performance of the automotive engines due to resultant soot build-up. This paper reviews the effects that attempts by stakeholders to satisfy requirements for reduced fuel consumption, reduced emissions and extended service intervals have had on increasing soot levels to an extent that can lead to engine component failure. Three areas have been identified that have either not been explored or not widely explored in the study of automotive soot namely: numerical simulation and modelling of soot wear, soot effects on wear of actual engine components and the wear and friction performance of non-metallic materials used in internal combustion engines. A paper-grading system is also utilised to present an overview of how sooty oil-related research covers various areas.     

Fault detection and diagnostic method of diesel engine by combining rule-based algorithm and BNs/BPNNs

The stable operation of diesel engine is critical to the normal production of the industry, and the prevention, monitoring, and identification of faults are of great significance. At present, the fault research on diesel engines still has some defects, such as only few types of faults diagnosis are identified, the accuracy of fault diagnosis is still low, and fault identification is located at a fixed speed. A novel fault detection and diagnostic method of diesel engine by combining rule-based algorithm and Bayesian networks (BNs) or Back Propagation neural networks (BPNNs) is proposed. The signals are processed by wavelet threshold denoising and ensemble empirical mode decomposition. The signal-sensitive feature values are extracted from the decomposed intrinsic mode function. Seven faults are roughly identified using rule-based algorithm and finely identified using BNs or BPNNs. Results show the proposed fault diagnosis method has a good diagnostic performance for a wide range of rotation speeds when the training data for BNs and BPNNs are from fixed speeds. In addition, the influences of the layers of decomposed signals, sensor noise and external excitation interference on the fault diagnostic performance are also researched.