宝马开发喷雾引导直喷稀薄燃烧发动机

德国宝马日前宣布开发成功了采用压电喷射阀的喷雾引导（Spray—guided）式直喷直列6缸稀薄燃烧发动机，并表示今后将阶段性地扩大配备车型及其市场。与原来的进气口喷射发动机相比，在最大输出功率略有提高的同时，可将燃效改善10％。     

缸内直喷醇类燃料发动机的燃烧与排放特性

根据所测的示功图和排放,分析了一台采用火花点火、缸内直喷周向分层燃烧系统的发动机在燃用甲醇和乙醇时的性能和燃烧特性。研究表明,醇类燃料发动机的燃烧由预混燃烧与扩散燃烧组成,具有非常快的燃烧速率,而且非常稳定,ATDC(3°CA～6°CA)就燃烧完50%燃料,循环变动小于6%。与燃用乙醇相比,燃用甲醇时滞燃期较短,燃烧速率较快。由于采用分层燃烧,醇类燃料发动机具有与直喷柴油机相当的热效率,在负荷特性上,燃用醇类燃料时的NOx排放仅为柴油机的10%～40%,且能实现无烟燃烧,CO排放的增加低于1%,HC排放高于柴油机。     

降低汽车发动机排放的技术

从机内净化技术，机外净化技术和应用清洁燃料等方面讨论了降低汽车发动机排放技术，对车用发动机分层充气预混合稀薄燃料（MPFI）、汽油机直喷燃烧（GDI）和均质混合压缩点火式燃烧（HCCI）等燃烧技术，选择催化还原剂（SCR）、NOx存储器还原催化系统（NSR）、等离子体辅助催化剂等新的稀燃NOx催化剂和微粒处理系统，通过这些技术的综合运用达到不断严格的排放标准和环保要求。     

燃油直喷燃烧技术

这一新技术的基础技术的应用起源于20世纪30年代,但长期以来没有得以发展,只是到了近些年．由于电子技术和其它系统性能的提高．才使这种新概念有所作为。     

直喷汽油机燃烧系统开发中的喷雾激光诊断技术

我国的直喷汽油发动机（SIDI）技术开发还不成熟。在SIDI燃烧系统的研发中,激光诊断、三维计算流体力学（3-DCFD）和基于光学发动机的燃烧诊断是三种重要技术。激光诊断技术可对燃油雾化与蒸发过程进行可视化以及定量测量,为数值计算和建模提供实验验证进而提高仿真的精确性,为缸内混合气形成过程及燃烧诊断提供直观的物理描述和...     

缸内直接燃烧——从化油器到SIDI缸内直喷技术

近期，随着新一代凯迪拉克CTS中国上市，其3．6升SIDI缸内直喷发动机技术随之浮出水面，有关“缸内直喷”技术的话题再度热门起来。什么是缸内直喷技术，这项技术有哪些特点，我们一起来看。     

汽油机缸内直喷稀薄燃烧技术(GDI)

在对GDI燃油喷射系统和燃烧系统等关键技术的介绍基础上,通过对GDI缸内流场的结构、在不同负荷下混合气分区域控制模式分析,阐明缸内直喷汽油机的工作过程、燃油经济性及排放特点。     

内燃机燃烧新技术

介绍了均质充量压缩点火（HCCI）燃烧和均质混合气引燃（HCII）燃烧技术及其实施策略。指出了HCCI燃烧和HCII燃烧需要解决的问题。     

Experimental investigation of B20 combustion and emissions under various intake conditions for low-temperature combustion

Recently, biodiesel has emerged as an alternative fuel for achieving low-temperature combustion (LTC). Several articles in the literature have showed that oxygenated biofuels, including biodiesel, can improve combustion stability under high exhaust gas recirculation (EGR) operation, which is considered to be necessary for the removal of nitric oxides (NOx). The objective of this study was to investigate the performance and emissions of 20% biodiesel blended diesel fuel (B20) at various intake pressures and oxygen concentration levels to characterize the fuel for LTC application. The experimental investigation of B20 was carried out using a single-cylinder engine (SCE) at 1400 rpm and 50% load condition. A set of critical flow orifices with synthetic EGR was employed to simulate various intake pressures and EGR levels. The behavior of the B20 was first characterized under various intake conditions. The results showed that with high oxygen intake, B20 exhibited combustion and emission levels that were very similar to conventional diesel. However, B20 reduced combustion deterioration while exhibiting lower carbon monoxide (CO) and hydrocarbon (HC) emissions than diesel under low oxygen intake conditions.     

如果内燃机还能风光20年

电动汽车的时代也许还要20年才能到来,目前的时间仍然是内燃机的时代,但我们可以看到内燃机却已是强弓之末。因为即便是再先进的内燃机,仍然需要消耗化学能,需要排放。     

公交车自燃背后的“标准”与“成本”

6月5日，成都发生公交车纵火案件，造成重大人员伤亡；6月13日，广东深圳一辆公交车发生自燃，短短10几分钟，车子只剩下一具残骸；6月15日，江苏常州市一辆BRT快速公交车发动机舱突然冒烟起火，所幸司机发现及时措施得当，并没有引发大火；6月17日浙江舟山13路空调车发动机部位起火，5分钟内整辆车全部被大火吞噬，烧的只剩下骨架。一时间人们谈“公交车”色变。     

某载货汽车自燃的分析

本文首先通过驾驶员对自燃过程的描述和整车初查,确定起火区域。其次,通过对种种自燃原因的排除,确定该故障的起火点。最后,通过自燃的分析,识别设计、装调缺陷,提出预防方案。     

车用发动机的燃烧测试技术

本文介绍AVL公司研制的AVL高速照相摄影装置及其使用方法。此法应用内窥镜进行燃烧过程高速照相。这是一种简便可行又实用的燃烧测试方法。本文对研究燃烧过程有参考价值。     

Influence of injection parameters on the transition from PCCI combustion to diffusion combustion in a small-bore HSDI diesel engine

In this paper, the influence of injection parameters on the transition from Premixed Charge Combustion Ignition (PCCI) combustion to conventional diesel combustion was investigated in an optically accessible High-Speed Direct-Injection (HSDI) diesel engine using multiple injection strategies. The heat release characteristics were analyzed using incylinder pressure for different operating conditions. The whole cycle combustion process was visualized with a high-speed video camera by simultaneously capturing the natural flame luminosity from both the bottom of the optical piston and the side window, showing the three dimensional combustion structure within the combustion chamber. Eight operating conditions were selected to address the influences of injection pressure, injection timing, and fuel quantity of the first injection on the development of second injection combustion. For some cases with early first injection timing and a small fuel quantity, no liquid fuel is found when luminous flame points appear, which shows that premixed combustion occurs for these cases. However, with the increase of first injection fuel quantity and retardation of the first injection timing, the combustion mode transitions from PCCI combustion to diffusion flame combustion, with liquid fuel being injected into the hot flame. The observed combustion phenomena are mainly determined by the ambient temperature and pressure at the start of the second injection event. The start-of-injection ambient conditions are greatly influenced by the first injection timing, fuel quantity, and injection pressure. Small fuel quantity and early injection timing of the first injection event and high injection pressure are preferable for low sooting combustion.     

汽车自燃的预防与紧急处理

随着经济的发展,汽车逐渐普及,汽车自燃因危害巨大,越来越受到人们的关注。本文系统地分析汽车自燃的原因,并阐述了五个方面的预防措施,以及发生自燃后,如何紧急处理减少损失。     

Applicability of heat transfer equations to hydrogen combustion

Previous research by the authors showed that hydrogen combustion exhibits a higher cooling loss to the combustion chamber wall of an internal combustion engine compared to hydrocarbon combustion because of its higher burning velocity and shorter quenching distance. The high cooling loss means that reduction of the cooling loss is essential to establish a high thermal efficiency in hydrogen combustion engines. This research analyzed the applicability of equations to describe the heat transfer from burning gases to hydrogen combustion. The result shows that equations calculate a lower cooling loss than experimental values, and the use of correction coefficients does not accurately define the actual cooling rate. It is therefore concluded that the derivation of a new heat transfer equation for hydrogen combustion is necessary to improve the thermal efficiency of hydrogen fuelled engines.