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.     

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.     

增压柴油机瞬态特性的评估方法

通过分析发动机典型瞬态过程中的各个参数变化及能量传递关系,提出了一个通用的评价涡轮增压柴油机瞬态响应性能的方法,建立了发动机的关键结构参数、涡轮增压器尺寸、初始运行工况参数与瞬态响应性能指标的显式关系。采用一维计算模型对提出的评价指标在不同机型上进行了计算验证。研究结果表明,提出的涡轮增压柴油机瞬态性能评价方法适用性强,且在整机设计的初始阶段就能够定量研究瞬态性能并判别设计方案的可行性。     

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.     

Reduction of engine emissions via a real-time engine combustion control with an egr rate estimation model

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.     

Transient exhaust gas improvement by adaptive neural network

Three-way catalyzer (TWC) is the most common exhaust gas treatment device for gasoline engines. A/F must be, however, kept within very narrow range. The conventional engine control system can maintain this by OZ feedback in a steady state, but not in a transient state. To overcome this, feed-forward control was provided using the neural network (NN) which is suitable to nonlinear behavior. Moreover, the NN has an adaptive ability by providing an on-line backpropagation loop, so that it can deal with different characteristics of same-type engines, aging in the same engine, and so on. In the experiments, relatively good results were obtained.     

A study of a torque control algorithm for direct-injection gasoline engines

A new torque control system was developed for direct injection gasoline engines. The control algorithm was obtained through an analysis of torque behavior under lean combustion with the application of EGR. Tests were conducted in which the openings of both the throttle valve and EGR valve were used as the control parameters, and the fuel injection quantity was synchronized with the phase of the air flow into the cylinders. It was found that good correspondence was obtained between the actual torque and the target torque even when the air–fuel ratio and the EGR rate were changed under transient operating conditions.     

Study on pilot injection of DI diesel engine using common-rail injection system

In recent DI diesel engines designed to achieve high output and meet future exhaust regulation, the pilot injection control using a common-rail injection system is adopted. In this research, we developed visualization equipment for pilot combustion behavior of non-luminous flame to clarify the influence of pilot injection parameters (timing and quantity) on engine performance. As a result of this analysis, we clarified the influence of pilot injection parameters on pilot-main combustion and found the optimum pilot injection controlling method.     

直喷汽油机最佳点火提前角控制算法的研究

通过试验研究了点火提前角对直喷汽油发动机性能的影响，依据发动机实际运行情况通过理论分析与试验相结合，研究了外界因素对直喷汽油发动机最佳点火提前角的影响，给出了各因素对直喷汽油发动机最佳点火提前角相应的修正补偿，结合目前实际运用中对汽油发动机点火提前角的控制提出了一种对直喷汽油发动机最佳点火提前角的控制算法，该控制算法可更简单，更精确，更有效地实现对汽油直喷发动机的最佳点火提前角的控制。     

天然气/柴油双燃料发动机电控喷气技术研究

本文研制开发了天然气／柴油双燃料发动机的压缩天然气（ＣＮＧ）电控喷气系统。试验表明，电控喷气可以明显改善双燃料发动机的燃料经济性和排放性能，提高发动机的热效率。合理选择加载喷射压力和喷射相位可有效地提高燃烧速度和燃烧稳定性。     

Iterative Learning Control Algorithm for Feedforward Controller of EGR and VGT Systems in a CRDI Diesel Engine

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.     

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.     

Comparison of two injection systems in an HSDI diesel engine using split injection and different injector nozzles

The demand for reduced pollutant emissions has motivated various technological advances in passenger car diesel engines. This paper presents a study comparing two fuel injection systems and analyzing their combustion noise and pollutant emissions. The abilities of different injection strategies to meet strict regulations were evaluated. The difficult task of maintaining a constant specific fuel consumption while trying to reduce pollutant emissions was the aim of this study. The engine being tested was a 0.287-liter single-cylinder engine equipped with a common-rail injection system. A solenoid and a piezoelectric injector were tested in the engine. The engine was operated under low load conditions using two injection events, high EGR rates, no swirl, three injection pressures and eight different dwell times. Four injector nozzles with approximately the same fuel injection rate were tested using the solenoid injection system (10 and 12 orifice configuration) and piezoelectric system (6 and 12 orifice design). The injection system had a significant influence on pollutant emissions and combustion noise. The piezoelectric injector presented the best characteristics for future studies since it allows for shorter injection durations and greater precision, which means smaller fuel mass deliveries with faster responses.     

新型共轨蓄压式电控燃油系统及32位ECU

本文介绍了一种新型共轨蓄压、喷油规律可调式电控柴油喷射系统，该系统成功实现了高压喷射以及喷油压力、喷油量和喷油定量的灵活控制，并具有预喷射和快速停油功能，同时还具有调整喷油速率的能力。通过对中压供油系统的优化设计，实现了优良的共轨油压调节特性。为了适应未来高性能车用柴油机管理系统的需要，首次采用32位单片机，开发一种功能完善的ECU，该ECU不仅能实现对电控然油系统的完善控制，而且还具有对增压器、EGR等的控制能力。     

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。     

基于CRUISE软件某燃油车动力系统建模与匹配

汽车动力系统的匹配,决定着汽车动力性能和经济性能的好坏,决定着所选动力的有效发挥。这一性能主要取决于发动机特性、传动系参数,以及这二者之间的相互匹配。文章通过AVL-CRUISE软件建立整车仿真模型,并对提供的四个发动机和两个变速器进行合理地匹配,并比较匹配结果的动力性和经济性,找到一种最佳的匹配方案。     

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。     

Adaptation Strategy for Exhaust Gas Recirculation and Common Rail Pressure to Improve Transient Torque Response in Diesel Engines

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.     

基于Elman神经网络的车用汽油机过渡工况空燃比辨识

以HL495Q型电喷汽油机为研究对象,分析了汽油机空燃比的数学模型,提出了一种基于Elman神经网络的过渡工况空燃比辨识方法。试验结果表明,Elman神经网络空燃比模型具有简单的网络结构,能高精度地逼近车用汽油机空燃比的实际动态过程,模型的平均相对误差小于1%,优于前馈BP神经网络模型的辨识结果。建立的Elman神经网络空燃比模型能改善过渡工况空燃比控制精度,提高排放性能。     

Assessment of diesel combustion noise overall level in transient operation

Combustion noise in passenger cars powered with direct injection (DI) diesel engines is frequently the main reason why end-users are reluctant to drive this type of vehicle. Thus, the great potential of diesel engines for environment preservation — due to their lower CO₂ emissions — could be missed. This situation worsens with the current design trends (engine downsizing) and the emerging new diesel combustion concepts (Homogeneous Charge Compression Ignition-HCCI, Premixed Charge Compression Ignition-PCCI, etc.), which are intrinsically noisy. This negative feature can be even more critical in transient operation due to the contribution of the temporal changes of both source and transmission path on engine noise. Therefore, combustion noise must be considered as an additional essential factor in engine development, together with performance, emissions and driveability. Thus, suitable evaluation procedures that can be integrated into the global engine development process in a timely and cost-effective manner are imperative. Regarding the evaluation procedures, most of the work available in the literature addressed combustion noise at steady operation. To surpass this limitation, two possible approaches — adapted from the classical and multiple regression methods — for the overall level assessment of combustion noise in transient conditions are evaluated in this paper.