电控高压共轨柴油机的喷油量与喷油规律

通过构造一种试验方法对高压共轨系统的喷油量与喷油规律进行测量,并分析其喷油规律。     

电控柴油机燃油喷射技术

柴油机电控燃油喷射系统在满足排放法规的条件下,能大大提高柴油机的燃油经济性和动力性。柴油机电控燃油喷射系统是在传统燃油喷射系统基础上发展起来的,由位置控制和时间控制两种主要形式构成。柴油机高压燃油共轨技术被公认为20世纪3大突破之一,将成为21世纪柴油机燃油系统的主流。分析柴油机电控燃油喷射系统的优点、类型及应用,着重介绍柴油机电控燃油喷射系统的控制原理。     

汽车电喷发动机控制系统的主要控制部件

随着电子技术的快速发展和节能减排的需要,现代汽车已广泛采用电喷发动机。本文介绍其控制系统的组成及主要控制部件的性能和结构特点。     

Effects of mixture stratification on HCCI combustion of DME in a rapid compression and expansion machine

Compression ignition of homogeneous charges in internal combustion (IC) engines is expected to offer high efficiency of DI diesel engines without high levels of NOx and particulate emissions. This study is intended to find ways of extending the rich limit of HCCI operation, one of the problems yet to be overcome. Exhaust emissions characteristics are also explored through analyses of the combustion products. DME fuel, either mixed with air before induction or directly injected into the combustion chamber of a rapid compression and expansion machine, is compressed to ignite under various conditions of compression ratio, equivalence ratio, and injection timing. The characteristics of the resulting combustion and exhaust emissions are discussed in terms of the rate of heat release computed from the measured pressure, and the concentrations of THC, CO, and NOx are measured by FT-IR and CLD. The experimental data to date show that operation without knock is possible with mixtures of higher equivalence ratio when DME is directly injected rather than when it is inducted in the form of a perfectly homogeneous fuel-air mixture. Although fuel injected early in the compression stroke promotes homogeneity of the DME-air mixture in the cylinder, it causes the mixture to ignite too early to secure good thermal efficiency and knock-free operation at high loads. Low temperature reactions occur at about 660K regardless of the fueling methods, fuel injection timing and equivalence ratio. The main components of hydrocarbon emissions turned out to be unburned fuel (DME), formaldehyde and methane.     

Experimental investigation of characteristics of pressure modulation in a fuel injection system

A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future.     

基于故障注入的CTCS-3级列控系统仿真测试的研究

在基于HLA的CTCS-3级仿真测试架构平台上,提出基于故障注入的测试方法,根据概率机制提取故障测试案例,对虚拟系统和实物系统可进行单故障或多故障耦合注入,并在实际线路上测试,效果良好.     

电控多点喷射LPG发动机的开发

提出对NJG427发动机进行电控多点LPG发动机改造的总体设计方案,对电控系统的硬件与软件进行了设计,进行了大量的发动机性能和排放试验。试验结果表明,改造方案切实可行,电控系统工作性能稳定可靠,改造后的燃气发动机性能指标和排放都达到了预定设计目标,满足轻型货车、城市中巴和支线公交的使用要求。     

摩托车发动机电子控制系统设计

选用AT89S52单片机,设计了轻骑踏板车GY6发动机的电子控制系统,并进行了系统调试,实现了各工况下电控系统对点火提前角及喷油脉宽的控制。     

自然通气降低导管螺旋桨空泡噪声试验和理论分析

我们已在文献中报导了通过导管24个周向分布径向孔,向螺旋桨叶梢部位人工低压充气(进口压力为2～3个大气压),可降低导管螺旋桨噪声达20分贝左右,当螺旋桨背面出现泡状空泡的强噪声源时,降低空泡噪声效果尤为显著,可高达30分贝左右。 本文继续研究,利用螺旋桨盘面上部的负压,采用自然通气,在导管上开一个孔、四个孔、八个孔向螺旋桨叶梢部位小气量通气降噪的试验和理论分析。试验证实:自然小气量通气在频率2～40千赫范围内可降低螺旋桨空泡噪声约4～12分贝左右。并从理论上分析了自然小气量通气后,可使空泡崩溃延缓;降低崩溃速度;降低辐射声能和声压;延长崩溃时间;结果可降低空泡噪声最高达15分贝左右,这与试验结果相当一致。虽然降噪幅度不及人工低压充气的降噪幅度大,但自然通气的最大优点是无需外加气源,因此更具有实用价值。试验还证实了不论是人工低压充气还是自然通气,不仅是降噪的非常有效的措施,而且也是抗剥蚀、减振的有力措施。     

柴油微引燃喷射策略对双燃料柴油机RCCI燃烧性能的影响

双燃料柴油机采用柴油微引燃天然气的RCCI(reactivity controlled compression ignition,RCCI)燃烧方式能够优化排放和经济性能.本文研究微引燃柴油采用3次喷射的方式,即预喷、主喷和尾喷分别控制预喷、主喷和尾喷的喷射始点时刻,通过仿真实验的方法研究其对柴油机缸内压力、温度、放热...