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汽车柴油机喷射控制单元的研究 总被引:2,自引:4,他引:2
汽车柴油机喷射控制单元是对缸内高压喷射的电子控制,其难点在于高速强力电磁阀的功率驱动硬件 和基于角度的喷射实时控制软件。本文介绍了电控泵-管-阀-嘴柴油喷射系统中电控单元的研究与开发实践。采用高频脉宽调制功率驱动电路进行电磁阀的高速强力驱动,并利用电流微分信号有效反馈了控制阀关闭始点。应用闭环控制逻辑和基于中断环的喷射控制软件实现了驱动电流的智能控制、喷射定时及油量的实时精确控制。最后通过实验证了 相似文献
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基于XC164电控组合单体泵控制单元的研究 总被引:1,自引:0,他引:1
介绍了以XC164为MCU的电控组合单体泵电控单元的研究。联合凸轮轴信号和曲轴信号,实现了快速准确判缸;利用XC164的输入捕获/重载功能倍频曲轴信号,大大提高了曲轴位置检测的精度,实现喷油正时的精确控制;采用高低端驱动和高低电压切换以及电流闭环控制技术,对单体泵电磁阀进行驱动控制,实现了电磁阀高速开关控制。该控制单元经油泵及发动机台架试验验证,满足电控组合单体泵系统要求。 相似文献
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中大客车采用了电控空气悬架(ECAS)系统。其电控单元(ECU),根据传感器的输入信号,通过电磁阀来控制气囊的动作。除控制正常行车高度外,与开关配合,ECU也可实现其他控制功能。 相似文献
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针对汽车自动变速器电控系统的结构,分析速比电磁阀、锁止电磁阀、调压电磁阀、蓄压器调节电磁阀、强制离合器电磁阀的控制原理;介绍自动变速器电控系统的一般诊断方法,电控系统检测(包括故障码检查、手动档试验和控制功能的检测),手动档试验(包括手动操纵试验和手动电磁阀试验),控制功能的检测(包括传感器、执行器的检测)。 相似文献
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In modern four-stroke automotive engine technology, variable valve timing and lift control offer potential benefits for making
a high-performance engine. In this paper, a novel design named dual-mode electrohydraulic fully variable valve train (EHFVVT)
for both engine intake and exhaust valves is introduced. The system is mainly controlled by either proportional flow control
valves or proportional pressure relief valves, and hence two different families of valve displacement patterns can be achieved.
The construction of the mathematical model of the valve train system and its dynamic analysis are also presented in this paper.
Experimental and simulation results show that the dual-mode electrohydraulic variable valve train can achieve fully variable
valve timing and lift control, and has the potential to eliminate the traditional throttle valve in the gasoline engines.
With the proposed system, the engine performance at various speeds and loads will be significantly improved. 相似文献
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G. T. Chala A. R. A. Aziz F. Y. Hagos 《International Journal of Automotive Technology》2017,18(1):85-96
There is an increasing interest in supercharging spark ignition engines operating on CNG (compressed natural gas) mainly due to its superior knock resisting properties. However, there is a penalty in volumetric efficiency when directly injecting the gaseous fuel at early and partial injection timings. The present work reports the combined effects of a small boost pressure and injection timing on performance and combustion of CNG fueled DI (direct injection) engine. The experimental tests were carried out on a 4-stroke DI spark ignition engine with a compression ratio of 14. Early injection timing, when inlet valves are still open (at 300°BTDC), and partial injection timing, in which part of the injection occurs after the inlet valves are closed (at 180°BTDC), were varied at each operating speed with variation of the boost pressure from 2.5 to 10 kPa. A narrow angle injector (NAI) was used to increase the mixing rate at engine speeds between 2000 and 5000 rpm. Similar experiments were conducted on a naturally aspirated engine and the results were then compared with that of the boosting system to examine the combined effects of boost pressure and injection timing. It was observed that boost pressure above 7.5 kPa resulted in an improvement of performance and combustion of CNG DI engine at all operating speeds. This was manifested in the faster heat release rates and mass fraction burned that in turn improved combustion efficiency of the boosting system. An increased in cylinder pressure and temperature was also observed with boost pressure compared to naturally aspirated engine. Moreover, the combustion duration was reduced due to concentration of the heat release near to the top dead center as the result of the boost pressure. Supercharging was also found to reduce the penalty of volumetric efficiency at both the simulated port and partial injection timings. 相似文献
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Seunghyun Lee Hoimyung Choi Kyoungdoug Min 《International Journal of Automotive Technology》2017,18(4):571-578
Vehicle emissions regulations are becoming increasingly severe and remain a principal issue for vehicle manufacturers. Since, WLTP (Worldwide harmonized Light vehicles Test Procedures) and RDE (real driving emission) regulations have been recently introduced, the engine operating conditions have been rapidly changed during the emission tests. Significantly more emissions are emitted during transient operation conditions compared to those at steady state operation conditions. For a diesel engine, combustion control is one of the most effective approaches to reduce engine exhaust emissions, particularly during the transient operation. The concern of this paper is about reducing emissions using a closed loop combustion control system which includes a EGR rate estimation model. The combustion control system calculates the angular position where 50 % of the injected fuel mass is burned (MFB50) using in-cylinder pressure for every cycle. In addition, the fuel injection timing is changed to make current MFB50 follow the target values. The EGR rate can be estimated by using trapped air mass and in-cylinder pressure when the intake valves are closed. When the EGR rate is different from the normal steady conditions, the target of MFB50 and the fuel injection timing are changed. The accuracy of the model is verified through engine tests, as well as the effect of combustion control. The peaks in NO level was decreased during transient conditions after adoption of the EGR model-based closed loop combustion control system. 相似文献
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The objective of this work was to investigate the effects of injection conditions and swirl on D.I. diesel combustion using
a transparent engine system. The test engine is equipped with a common rail injection system to control injection conditions
and to obtain split injection characteristics. A combustion analysis and steady flow test were conducted to measure the heat
release rate due to cylinder pressure and the swirl ratio. In addition, spray and diffusion flame images were obtained using
a high speed camera. The LII & LIS methods were also used to obtain 2-D soot and droplet distributions. High injection pressure
was found to shorten ignition delay, as well as to enhance peak pressure. The results also revealed that the heat release
rate in the premixed combustion region was markedly reduced through the use of pilot injection, while the soot distribution
and the heat release rate in the diffusion combustion region were increased. The swirl effect was found to shorten ignition
delay at certain injection timings, and to enhance the heat release rate in all experimental conditions. 相似文献
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