Fueling Control of Spark Ignition Engines

Presented in this paper is an adaptive, model based, fueling control system for spark ignition-internal combustion engines. Since the fueling control system is model based, the engine maps currently used in engine fueling control are eliminated. This proposed fueling control system is modular and can therefore accommodate changes in the engine sensor set such as replacing the mass-air flow sensor with a manifold air pressure sensor. The fueling algorithm can operate with either a switching type O 2 sensor or a linear O 2 sensor. The fueling control system is also parceled into steady state fueling compensation and transient fueling compensation. This feature provides the distinction between fueling control adaptation for transient fueling and steady state fueling. The steady state fueling compensation utilizes a feedforward controller which determines the necessary fuel pulsewidth after a throttle transient to achieve stoichiometry. This feedforward controller is comprised of two nonlinear models capturing the steady state characteristics of the fueling process. These models are identified from an input-output testing procedure where the inputs are fuel pulsewidth and mass-air flow signal and the output is a lambda signal. These models are adapted via a recursive least squares method to accommodate product variability, engine aging, and changes in the operating environment. The transient fueling compensation also utilizes a feedforward controller that captures the essential dynamic characteristics of the transient fueling operation. This controller is measured using a frequency domain system identification approach. This proposed fueling control system is demonstrated on a Ford 4.6L V-8 fuel injected engine.     

车用稀燃增压单一燃料CNG发动机电控系统的研究

为深入研究 CNG发动机稀薄燃烧特性 ,进一步降低天然气发动机的有害排放 ,设计了车用增压天然气发动机电控系统。该系统采用高能点火模块来获得天然气着火所需的点火能量 ,电控喷射单元采用模糊控制器来获得比较精确的空燃比控制 ,实现对天然气发动机的顺序多点喷射。运用该系统对增压单一燃料 CNG发动机的燃烧和排放性能进行了试验研究 ,结果表明了该系统的有效性。     

Fueling Control of Spark Ignition Engines

Presented in this paper is an adaptive, model based, fueling control system for spark ignition-internal combustion engines. Since the fueling control system is model based, the engine maps currently used in engine fueling control are eliminated. This proposed fueling control system is modular and can therefore accommodate changes in the engine sensor set such as replacing the mass-air flow sensor with a manifold air pressure sensor. The fueling algorithm can operate with either a switching type O 2 sensor or a linear O 2 sensor. The fueling control system is also parceled into steady state fueling compensation and transient fueling compensation. This feature provides the distinction between fueling control adaptation for transient fueling and steady state fueling. The steady state fueling compensation utilizes a feedforward controller which determines the necessary fuel pulsewidth after a throttle transient to achieve stoichiometry. This feedforward controller is comprised of two nonlinear models capturing the steady state characteristics of the fueling process. These models are identified from an input-output testing procedure where the inputs are fuel pulsewidth and mass-air flow signal and the output is a lambda signal. These models are adapted via a recursive least squares method to accommodate product variability, engine aging, and changes in the operating environment. The transient fueling compensation also utilizes a feedforward controller that captures the essential dynamic characteristics of the transient fueling operation. This controller is measured using a frequency domain system identification approach. This proposed fueling control system is demonstrated on a Ford 4.6L V-8 fuel injected engine.     

Measurement of hydrocarbon and carbon monoxide emissions during the starting of automotive DI Diesel engines

Most of hydrocarbon (HC) and carbon monoxide (CO) emissions from automotive DI Diesel engines are produced during the engine warm-up period and are primarily caused by difficulties in obtaining stable and efficient combustion under these conditions. Furthermore, the contribution of engine starting to these emissions is not negligible; since this operating condition is highly unfavorable for the combustion progress. Additionally, the catalytic converter is ineffective due to the low engine temperature. In conjunction with adequate engine settings (fuel injection and fresh air control), either the glow plugs or the intake air heater are activated during a portion of the engine warm-up period, so that a nominal engine temperatures is reached faster, and the impact of these difficulties is minimized. Measurement of gaseous pollutants during engine warm-up is currently possible with detectors used in standard exhaust gas analyzers (EGA), which have response times well-suited for sampling at such transient conditions. However, these devices are not suitable for the measurement of exhaust emissions produced during extremely short time intervals, such as engine starting. Herein, we present a methodology for the measurement of the cumulative pollutant emissions during the starting phase of passenger car DI Diesel engines, with the goal of overcoming this limitation by taking advantage of standard detectors. In the proposed method, a warm canister is filled with an exhaust gas sample at constant volumetric flow, during a time period that depends on the engine starting time; the gas concentration in the canister is later evaluated with a standard EGA. When compared with direct pollutant measurements performed with a state-of-art EGA, the proposed procedure was found to be more sensitive to combustion changes and provided more reliable data.     

Development of engine control using the in-cylinder pressure signal in a high speed direct injection diesel engine

Emission regulations are becoming more stringent and remain a principal issue for vehicle manufacturers. Many engine subsystems and control technologies have been introduced to meet the demands of these regulations. For diesel engines, combustion control is one of the most effective approaches for reducing not only engine exhaust emissions but also cylinder-by-cylinder variation. However, the high cost of pressure sensors and the complex engine head design for additional equipment present difficulties for manufacturers. In this paper, cylinder pressure-based engine control logic is introduced for a multi-cylinder high speed direct injection (HSDI) diesel engine. The time for 50% of the mass fraction to be burned (MFB50) and the IMEP are valuable for determining the combustion status. These two in-cylinder quantities are measured and applied to the engine control logic. Fuel injection timing is controlled to adjust the operating MFB50 to the target MFB50 using PID control logic, and the fuel injection quantity is controlled to adjust the measured IMEP to the desired IMEP. The control logic is demonstrated at steady state and during transient conditions and is applied to an NEDC mode test.     

汽油机电控系统开发的计算机辅助试验系统

汽油机电子控制系统与发动机的匹配试验是电控汽油机开发的关键环节，它决定着整机性能的优劣及开发周期的长短。本文开发了一套计算机辅助试验系统。根据配机试验在要求在线修改控制参数，得到满足发动机性能要求的最佳值。该系统在几种电控汽油机的开发中得到了成功的应用。     

国外车用柴油机SCR技术的应用研究

机外措施是控制柴油机NOx 排放的有效措施,是柴油机排放控制的关键技术。选择催化还原(SCR)技术是降低车用柴油机NOx 排放的机外措施之一。介绍了SCR技术的理论依据、系统组成及工作原理;重点介绍了国外车用柴油机SCR技术的应用情况及还需解决的问题。     

一种新型汽车发动机集中控制系统

介绍了一种新型汽车发动机集中控制系统。该系统由汽车发动机数据生成、仿真系统和汽车发动机集中控制装置组成。发动机数据生成、仿真系统可以完成发动机ESA、EFI、ISC和EGR控制所需基本参数的输入以及控制模式选择和系统仿真。发动机集中控制装置具备自诊断、实时监控和后备控制功能，可以使用通信功能实现系统软件升级及数据更新。     

Modeling and simulation of a dual-mode electrohydraulic fully variable valve train for four-stroke engines

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.     

基于神经网络的柴油机NO_x排放实时仿真模型

传统的NOx排放模型都是基于Zeldovich链式反应,其大量的计算无法满足HILSS(硬件在环仿真系统)实时仿真的要求。而根据各种影响因素与NOx生成量之间的映射关系,用神经网络方法来构建NOx排放模型是一种同时兼顾实时性和准确性的解决方案。所建立的基于BPNN的NOx排放模型,采用贝叶斯正则化训练算法提高BP网络的推广能力,具有简单、可靠和通用的特点,可以在一定程度上预测发动机瞬态工况的NOx排放。     

索纳塔轿车发动机故障自诊断

北京现代索纳塔轿车采用2．0L、2．4L4缸发动机和2．7LV6发动机，这几种发动机均采用顶置双凸轮轴、多点燃油喷射和直接点火系统。发动机ECU采用OBD-2型自诊断通信系统，如果发动机控制系统出现故障，ECU会存储相应的4位数故障代码，维修时可利用扫描仪提取故障代码。以2．4L4缸发动机为例，将有关问题简述如下。     

Influence of the accelerating operation mechanism on the combustion noise in DI-diesel engines

This paper focuses on the mechanisms of combustion noise during the accelerating operation of multi-cylinder diesel engines using testing technology for the transient conditions of IC engines. Based on impact factors, such as the gas dynamic load and cylinder pressure oscillations, tests and analysis of the combustion noise during transient and steady-state conditions for different loads are made on four-cylinder naturally aspirated engines, turbocharged engines, EGR-introduced engines, and high pressure common rail engines. The laws of combustion noise difference for the same engine speed and load are researched during transient and steady-state conditions. It is found that during transient conditions, the maximum pressure rise rate and the high frequency oscillation amplitude of the cylinder pressure are all higher than those observed during steadystate conditions for the same engine speed and load. With their joint action, the combustion noise during transient conditions is greater than that during steady-state conditions. Turbocharging is useful in reducing the combustion noise during transient conditions. Turbocharging has a better effect on the control over the combustion noise during transient conditions with a constant engine speed and an increasing torque than in conditions with a constant torque and an increasing engine speed. One of the main reasons for different control effects on the combustion noise is that turbocharging causes different wall temperatures inside combustion chambers. The introduction of the appropriate EGR is helpful in the reduction of the combustion noise during transient conditions. The key to the control of combustion noise with EGR during transient conditions is whether a real-time adjustment to the EGR rate can be made to achieve the optimization of the EGR rates for different transient conditions. By means of analyzing the differences in the combustion noise between the transient and steady-state conditions for different pilot injection controls, we obtain a strategy for controlling the combustion noise during transient conditions with a pilot injection. Compared with the steady-state conditions, a larger pilot injection quantity and a longer interval between the main injection and pilot injection should be selected for transient conditions, and this is verified through tests.     

Model based burnt gas fraction controller design of diesel engine with VGT/Dual loop EGR system

-Recently, regulation of NOx and PM emission in diesel engines has become stricter and the EGR system has been expanded into a dual loop EGR system to increase EGR rate as well as to utilize exhaust gas strategically. In terms of engine combustion characteristics, burnt gas fraction is becoming an important factor of solving the NOx and PM emission reduction problem more efficiently but conventional controller focused only pressure and air flow rate targets. Unlike the previous studies, this paper describes a model based burnt gas fraction control structure for a diesel engine with a dual loop EGR and a turbocharger. Feedforward control inputs based on burnt gas fraction states aids in the precise control of diesel engines, especially in transient states by considering coupled behavior within the system. For the controller validation, a control oriented reduced order model of a diesel engine air management system is established to simplify the control input computation and its stability is proved by analysing the internal dynamics stability. Then, a sliding mode controller is designed and controller robustness at certain operating points is validated using an HiLS bench.     

高压共轨电喷柴油机调速控制策略研究

以高压共轨电喷柴油机为研究对象,对其调速控制策略进行了研究。建立了电喷柴油机的控制模型,并对PID控制和自适应控制进行了仿真比较。结果表明自适应控制具有明显的优势,更适合于高压共轨电喷柴油机速度控制。     

Numerical investigation of turbolag reduction in HD CNG engines by means of exhaust valve variable actuation and spark timing control

Turbocharging port-injected Natural Gas (NG) engines allows them to recover gaseous-fuel related power gap with respect to gasoline engines. However, turbolag reduction is necessary to achieve high performance during engine transient operations and to improve vehicle fun-to-drive characteristics. Significant support for the study of turbocharged Compressed Natural Gas (CNG) engines and guidelines for the turbo-matching process can be provided by 1-D numerical simulation tools. However, 1-D models are predictive only when a careful tuning procedure is set-up and carried out on the basis of the experimental data. In this paper, a 1-D model of a Heavy-Duty (HD) turbocharged CNG engine was set up in the GT-POWER (Gamma Technologies Inc., Westmont, IL, US) environment to simulate transient operations and to evaluate the turbolag. An extensive experimental activity was carried out to provide experimental data for model tuning. The model buildup and tuning processes are described in detail with specific reference to the turbocharger model, whose correct calibration is a key factor in accounting for the effects of turbine flow pulsations. The second part of the paper focuses on the evaluation of different strategies for turbolag reduction, namely, exhaust valve variable actuation and spark timing control. Such strategies were aimed at increasing the engine exhaust-gas power transferred to the turbine, thus reducing the time required to accelerate the turbocharger group. The effects of these strategies were examined for tip-in maneuvers at a fixed engine speed. Depending on the engine speed and the applied turbolag reduction strategy, turbolag reductions from 70% to 10% were achieved.     

Efficiency and ecological characteristics of a VCR diesel engine

Compression ratio (CR) is a design parameter with highest influence on efficiency, emission and engine characteristics. In conventional internal combustion (IC) engines, the compression ratio is fixed and their performance is, therefore, a compromise between conflicting requirements. One fundamental problem is that drive units in the vehicles must successfully operate at variable speed and loads and in different ambient conditions. If a diesel engine has a fixed CR, a minimal value must be chosen that can achieve a reliable self-ignition when starting the engine in cold start conditions. In diesel engines, variable compression ratio (VCR) provides control of peak cylinder pressure, improves cold start ability and low load operation, enabling the multi-fuel capability, increase of fuel economy and reduction of emissions. By application of VCR and other mechanisms, the optimal regime fields are extended to the prime requirements: consumption, power, emission, noise, etc., and/or the possibility of the engine to operate with different fuels is extended. An experimental Diesel engine has been developed at the Faculty of Engineering, University of Kragujevac. The changes of CR are realized by changing the piston chamber diameter. Detailed engine tests were performed at the Laboratory for IC engines. Special attention has been given to decrease of fuel consumption and exhaust emissions. An optimal field of CR variation has been determined depending on the given objectives: minimal fuel consumption, minimal nitric oxides, and particulate matter emissions, etc.     

Efficiency improvement for an unthrottled SI engine at part load

Variable valve timing (VVT) and cylinder deactivation (CDA) are promising methods in reducing fuel consumption and emission at part load in SI engines. An SI engine which uses electromagnetic valvetrain (EMV) will eliminate flow restriction from the throttle valve and produce higher indicated mean efficiency pressure (IMEP) due to the disabling of some of the working cylinders at part load. Therefore, pumping loss can be significantly reduced at part-load conditions. In addition, duration and timing of valve events are variably controlled at different operating conditions. This contributes to the improvement of engine efficiency. In this study, a dynamic model of an unthrottled SI engine has been developed to simulate the engine cycle. The model uses an EMV system that allows valvetrain control and cylinder deactivation techniques to be carried out in simulation flexibly. The simulated results find the optimal valve timing for different engine speeds. The optimal timing of intake valve closing depends on engine speed linearly, while the intake valve opening insignificantly influences engine performance. Additionally, this study also shows that cylinder deactivation modes can be successfully applied in improving engine efficiency at different engine loads. Different cylinder deactivation strategies have been applied for the full range of engine loads. It is concluded that the two-cylinder deactivation mode (50% CDA) considerably improves fuel consumption at low engine load. Meanwhile, one-cylinder deactivation (25% CDA) is an optimal fuel economy mode at medium engine load. With proper uses of VVT and CDA strategies, the efficiency of an SI engine can be increased more than 30% at low engine load and 11.7 % at medium engine load.     

汽油机过渡工况进气流量的神经网络预测研究

进气流量的精确测量是车用汽油机空燃比精确控制的基础,发动机工作在过渡工况时,因进气状态变化,空气流量传感器的滞后响应影响了过渡工况空燃比的控制精度。提出了一种基于汽油机过渡工况各种参数信息融合的过渡工况进气流量预测方法,分析了影响汽油机过渡工况进气流量的各种工况参数,提取了特征参数并建立了BP神经网络信息融合预测模型。对车用汽油机加减速工况试验数据进行仿真,研究结果表明,该方法能够准确实时地预测汽油机过渡工况的进气流量,同时能够消除空气流量传感器的滞后特性。     

车用小型高速柴油机综合电控系统

本文介绍了小型高速柴油机分配式喷油泵综合电子控制系统。     

基于自适应模糊神经网络的故障诊断方法

对模糊逻辑和神经网络的优缺点进行分析,提出一种基于自适应模糊神经网络的故障诊断方法。它把模糊逻辑和神经网络有机结合起来,生成自适应模糊神经推理系统(ANFIS);文中给出了该系统的原理及实现算法,最后使用M atlab Fuzzy工具箱对柴油发动机喷油泵柱塞故障数据进行建模,结果表明该方法是可行的,并且有较高的诊断效率。