共查询到20条相似文献,搜索用时 171 毫秒
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基于模型的DPF主动再生排气温度控制 总被引:1,自引:0,他引:1
颗粒物捕集器(DPF)主动再生发生时需要将柴油发动机排气温度提升到500℃以上并维持在较长一段时间内。为减少由于控制对象纯滞后特性、强扰动因素引起的不确定性,降低高排气温度带来的主动再生风险,结合基于模型的控制策略提出了一种优化的再生温度控制算法和控制器结构,并展开了仿真分析、参数优化等研究工作。设计的控制结构考虑实际工程应用需求,采用基于发动机排气温度和排气流量的增益补偿和前馈加反馈控制方案,可兼顾性能和成本因素,并具有较强的适应性和可操作性。仿真和台架试验、车辆道路试验结果均表明,主动再生过程中对实际排温控制的超调量小于3%,在发动机瞬态工况和车辆运行等强扰动工作工况下的稳态控制误差小于25℃。 相似文献
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运转参数对火花点火发动机未燃HC排放影响的实验研究 总被引:1,自引:0,他引:1
本文开展了转速、混合气浓度、点义提前角、节气门开度及润滑油温度对火花点火发动机排气未然HC影响的实验研究,并分析了运转因素对HC排放的影响。实验结果表明,提高发动机转速,燃用较稀混合气,适当推迟点火和提高润滑油温度均可降低发动机排气中未然HC浓度。 相似文献
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EQ6100发动机排气门座耐磨性研究 总被引:1,自引:0,他引:1
近年来围绕排气门座耐磨性问题进行了一些工作,即材料对耐磨性的影响;汽油含铅量对耐磨性的影响;发动机的高温高负荷对耐磨性的影响;排气门座温度对耐磨性的影响;气门间隙随发动机温度升高的变化情况。现就以上几个方面工作进行分析如下: 一、材料对排气门座耐磨性的影响 1986年~1988年共抽检东风EQ140车汽油发动机EQ6100近60台进行100小时全速全负荷试验。在这些发动机中有采用现生产高 相似文献
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Seungwoo Hong Donghyuk Jung Myoungho Sunwoo 《International Journal of Automotive Technology》2018,19(4):585-595
Fuel injection limitation algorithms are widely used to reduce particulate matter (PM) emissions under transient states in diesel engines. However, the limited injection quantity leads to a decrease in the engine torque response under transient states. To overcome this issue, this study proposes an adaptation strategy for exhaust gas recirculation (EGR) and common rail pressure combined with a fuel injection limitation algorithm. The proposed control algorithm consists of three parts: fuel injection limitation, EGR adaptation, and rail pressure adaptation. The fuel injection quantity is limited by adjusting the exhaust burned gas rate, which is predicted based on various intake air states like air mass flow and EGR mass flow. The control algorithm for EGR and rail pressure was designed to manipulate the set-points of the EGR and rail pressure when the fuel injection limitation is activated. The EGR controller decreases the EGR gas flow rate to rapidly supply fresh air under transient states. The rail pressure controller increases the rail pressure set-point to generate a well-mixed air-fuel mixture, resulting in an enhancement in engine torque under transient states. The proposed adaptation strategy was validated through engine experiments. These experiments showed that PM emissions were reduced by up to 11.2 %, and the engine torque was enhanced by 5.4 % under transient states compared to the injection limitation strategy without adaptation. 相似文献
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Kyunghan Min Myoungho Sunwoo Manbae Han 《International Journal of Automotive Technology》2018,19(3):433-442
The modern diesel engines equip the exhaust gas recirculation (EGR) system to suppress the NOx emissions. In addition, the variable geometric turbocharger (VGT) system is installed to improve the drivability and fuel efficiency. These EGR and VGT systems have cross-coupled behavior because they interact with the intake and the exhaust manifolds. Furthermore, the turbocharger time delay, gas flow dynamics through EGR pipe cause the nonlinearity characteristics. These nonlinear multi-input-multi-output characteristics cause the degradation of control accuracy, especially during the transient condition. In order to improve the control accuracy, this study proposes an iterative learning control (ILC) algorithm for feedforward controller of EGR and VGT systems. The feedforward controller obtains the values about EGR and VGT actuators using the previous control results in predefined transient states. The ILC algorithm consists of a PD-type learning function and a low-pass filter. The control gains of learning function are determined to guarantee the convergence of learning results. In addition, the low-pass filter is designed for robustness against plant disturbance. The proposed control algorithm was validated by engine experiment which repeated predefined transient states. The error was reduced by 15 % according to the gain. As a result, the proposed algorithm is affordable for improving the transient control performance. 相似文献
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J. Lucas M. A. Houghton I. G. Masheter 《International Journal of Automotive Technology》2012,13(6):853-860
A system has been researched over the past 3 years for reducing the exhaust pollutants from diesel engines for light commercial vehicles. The system researched achieves Euro 6 standards for reduction of polluting gases (CO, HC, PM, NO). It consists of 4 main sections: 1. A heater and heat exchanger (HE); 2. A CO/HC oxidising catalyst (D°C); 3. Pt catalyst on a diesel particulate filter (DPF); 4. A NO reducing reaction (SCR) within the DPF. The system operates as follows. The exhaust gas contains oxidising gases, namely both O2 and NO2. The levels of CO and HC are oxidised by O2 to CO2 for temperatures above 200°C. Carbon (PM) is oxidised to CO2 by NO2 but requires a temperature above 250°C. The operating exhaust temperature of 300°C is ideal for the removal of NO by using the Pt catalyst and the CO generated within the DPF. The heater is required to be able to raise the exhaust temperature at any time to 300°C in order to optimise the performance of the system, since diesel engine exhaust temperatures vary between 160°C (slow speeds) to 350°C (high speeds). Considerable heat is required (??3 kW) to maintain the exhaust gas for a 2l engine at 300°C for engine idle conditions. Therefore a heat exchanger is required to re-circulate the input heat and thereby reduce the maximum power consumption to a maximum of 500W over the engine full operating test cycle. This energy is supplied by the engine battery and alternator. Experimental results have been obtained for the exhaust from a Kubota diesel engine and the reductions in exhaust emissions of 83% (CO/ HC), 58% (NOx) and 99% (PM) were obtained. The PM was continuously cleaned so that there was no build up of back pressure. 相似文献
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工作过程计算在发动机开发中的应用 总被引:6,自引:0,他引:6
GT-Power软件计算气体在流动方向上的压力、温度、流动速度等参数变化,从而可计算出发动机工作过程气体流动的变化过程,用来评价发动机性能指标的优劣。应用GT-Power软件,对发动机的凸轮型线及配气相位和排气管的结构尺寸进行了优化计算,并进行了增压器的匹配计算,对发动机排气制动功率和气体流动噪声计算进行了简单论述。 相似文献
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In this study, NOx conversion characteristics of a urea selective catalytic reduction (SCR) system equipped on a heavy-duty diesel engine were evaluated through engine dynamometer bench tests over a scheduled world harmonized transient cycle (WHTC). Also, based on transient SCR simulations, the thermal management strategy to improve SCR NOx conversion efficiency was investigated. As a result, it was found that a selective increase in exhaust temperature at low temperature period would be a useful measure to increase SCR efficiency on WHTC mode. From the baseline SCR efficiency of around 98 % on WHTC mode, the current simulation results have shown that around 99 % level of SCR efficiency would be achievable by increasing exhaust temperatures with modifying diesel exhaust fluid (DEF) dosage. Another valuable contribution of this study is that the design guidelines for controlling exhaust temperature and DEF injection to obtain a target NOx conversion efficiency are presented for SCR systems of heavy-duty diesel engines on transient operating conditions. 相似文献