内燃机激光多点点火技术研究进展

稀薄燃烧能够提高内燃机的热效率并降低污染物的排放, 但稀薄燃烧的火焰传播速度慢且在高压下易出现局部淬火现象。激光诱导火花点火能够有效解决燃料在低当量比和高压下燃烧遇到的问题，此外激光点火能够实现多点点火从而缩短燃烧时间并增大燃烧室压力, 相较于传统的电火花塞点火技术具有很大优势。锥形腔、衍射透镜、空间光调制器和达曼光栅均已被用于实现多点激光诱导火花点火。归纳了多点激光诱导火花点火的几种技术途径，讨论了内燃机多点激光诱导火花点火的研究状况和最新成果。对实现多点激光诱导火花点火的几种方法进行了评价，并指出了每种方法在多点激光诱导火花点火中的优势和需要解决的问题。在此基础上，对内燃机激光多点点火技术的研究前景进行了展望。     

Engine performance evaluation using a combustion probe signal analyzer

A two-channel combustion probe signal analyzer to detect variations in the combustion quality in spark ignition engines was built and its performance investigated. The combustion probe signal was obtained by applying a small positive bias to the center electrode of the spark plug of interest. This was accomplished by the insertion of an adaptor between the distributor cap and the spark plug wire. Use of the adapter showed no apparent effect on engine operating characteristics. Experiments investigating the correlation between several engine operating parameters and the combustion quality parameters "impaired combustion" and "slow combustion" were carried out. The parameters varied were A/F (air to fuel ratio), spark advance, engine speed, nonenriched cold start, and NOxand hydrocarbon concentrations in the exhaust. Dynamometer mounted 400 CID production engine was used. Good agreement was found to exist between the variation in the combustion probe signal analyzer's counts and progressively induced impairments of the combustion process.     

Nonlinear air-to-fuel ratio and engine speed control for hybrid vehicles

Internal combustion spark ignition engine management systems regulate the fuel, spark, and idle air subsystems to achieve sufficient engine performance at acceptable fuel economy and tailpipe emission levels. Engine control units also monitor other engine processes, using a suite of sensors, and periodically check the system actuators' operation to satisfy legislated onboard diagnostics. The majority of production engines regulate the air-to-fuel ratio using a speed-density, or air-flow, control strategy. In this approach, the mass of air drawn into a given cylinder is calculated using the engine speed, manifold absolute pressure, and inlet air temperature. Based on the air mass, appropriate fuel amounts are injected to achieve stoichiometric operation. However, the wide range of operating conditions, inherent induction process nonlinearities, and gradual component degradations due to aging have prompted research into model-based algorithms. In this paper, a nonlinear model-based control strategy will be proposed for simultaneous air-to-fuel ratio control and speed tracking in hybrid electric vehicles. The motivation for engine speed management resides in the integrated control of the engine and a continuously variable transmission for increased efficiency. The proposed backstepping controller uses an observer to reduce the inputs to manifold air mass (e.g., manifold absolute pressure and inlet air temperature) and engine speed. The underlying engine model describes the air intake, fuel injection, and rotational dynamics. For comparison purposes, an existing multisurface sliding mode controller and an integrated speed-density air-to-fuel controller with attached engine speed regulation have been implemented. The performance of each controller is studied using an analytical engine model with representative numerical results presented and discussed to provide insight into the overall performances.     

Adaptive and Learning Control for SI Engine Model With Uncertainties

Air--fuel ratio control is a challenging control problem for port-fuel-injected and throttle-body-fuel-injected spark ignition (SI) engines, since the dynamics of air manifold and fuel injection of the SI engines are highly nonlinear and often with unmodeled uncertainties and disturbance. This paper presents nonlinear control approaches for multi-input multi-output engine models, by developing adaptive control and learning control design methods. Theoretical proofs are established that ensure that proposed controllers are able to give asymptotical tracking performance. As a comparison, the method applying global linearizing controller can give accurate tracking for the engine model without uncertainty and disturbance, but it fails to keep tracking performance when uncertainty is incorporated into the system. Adaptive control and learning control approaches are capable of dealing with both constant uncertainty and time-varying periodic uncertainty. Simulation results illustrate the efficacy of the proposed controllers.      

A piezoelectric driven ratchet actuator mechanism with application to automotive engine valves

Increasing demands on the performance of internal combustion engines, specifically automobile engines, require the production of more mechanical energy for a given amount of chemical fuel with reduced tailpipe emissions. Of particular interest in the development of high performance/low emission engines is the control and timing of individual engine valves. This paper investigates the design of an innovative piezoelectric ceramic (PZT) based actuator mechanism with a novel stepping motion amplifier to deliver force and displacement at higher magnitudes and operating frequencies. The target application is an engine valve train which traditionally uses cam-based lifter driven rocker arms to regulate the cylinders’ intake and exhaust valve motion. The proposed PZT-based actuator mechanism introduces a high frequency, lightweight, precise position solution for cylinder-by-cylinder variable valve timing. Numerical results are provided to demonstrate the feasibility of a PZT-based/camless valve train. The new valve train demonstrates similar cam-based performance characteristics while enabling computer controlled individual valve timing opportunities.     

Monitoring the combustion quality in internal combustion engines using the spark plug as a plasma probe

A method of monitoring the quality of combustion in spark ignition gasoline engines using the spark plug's center electrode as a plasma probe is presented. Due to the ionized species remaining in the burned gases after combustion, a current is induced in a network attached to the spark plug's center electrode. The time dependence of this induced current is shown to correlate with the presence or absence and the time of occurance of the pressure component due to combustion in pressure transducer signals recorded simultaneously. Based on these correlations, three types of burns could be recognized from plasma probe signals: good burns, slow burns, and misfires. The specific correlation between the absence of a pressure component due to combustion and a corresponding absence of a plasma probe signal was used to form the basis for the operation of a one-channel engine misfire monitoring circuit.     

Hybrid Model Predictive Control of Direct Injection Stratified Charge Engines

This paper illustrates the application of hybrid modeling and model predictive control techniques to the management of air-to-fuel ratio and torque in advanced technology gasoline direct-injection stratified-charge (DISC) engines. A DISC engine is an example of a constrained hybrid dynamical system, because it can operate in two distinct modes (stratified and homogeneous) and because the mode-dependent constraints on the air-to-fuel ratio and on the spark timing need to be enforced during its operation to avoid misfire, knock, and high combustion variability. In this paper, we approximate the DISC engine dynamics as a two-mode discrete-time switched affine system. Using this approximation, we tune a hybrid model predictive controller with integral action based on online mixed-integer quadratic optimization, and show the effectiveness of the approach through simulations. Then, using an offline multiparametric optimization procedure, we convert the controller into an equivalent explicit piecewise affine form that is easily implementable in an automotive microcontroller through a lookup table of linear gains.     

Design and experimental implementation of an electromagnetic engine valve drive

In conventional internal combustion engines, engine valve displacements are fixed relative to crankshaft position. If these valves were actuated as a variable function of crankshaft angle, significant improvements in fuel economy could be achieved. To this end, a new type of electromagnetic valve drive system (EMVD) for internal combustion engines was more recently proposed. This EMVD incorporates a disk cam with a very desirable nonlinear profile which that functions as a nonlinear mechanical transformer. Modeling and simulation results showed significant advantages of this EMVD over previously designed electromagnetic engine valve drives. In this articles, we describe an experimental implementation of the proposed EMVD, which was developed to confirm these benefits. The EMVD apparatus was designed, constructed, and integrated into a computer-controlled experimental test stand. The experimental results confirm the benefits of using a nonlinear mechanical transformer in a motordriven engine-valve spring system, as seen in the small average power consumption and low valve seating velocity. In addition, a valve transition time sufficient for 6000-rpm engine operation was achieved. The results also suggest ways to improve the EMVD apparatus in the future.     

三菱M701F型燃气轮机静态变频装置调试探讨

随着世界各国对环境问题越来越重视,燃气轮机作为一种先进环保的发电设备应运而生。我国在燃气轮机方面起步较晚,其制造技术相对落后,近年来引进一批国外燃机。在目前国内燃机调试项目、相关的质量检验及评定标准还没有规范化的情况下,文章根据三菱M701F型燃气轮机静态变频装置的工作原理,结合国内常规电厂的调试经验,学习借鉴国外比较先进的调试方法,对调试过程中发生的问题进行分析。     

Modell zur Grenzkostenermittlung dezentraler Erzeugung

Due to the EIWOG-amendment the number of decentralized cogeneration systems will increase. Furthermore, decentralized energy supply systems like fuel cells, combustion engines and micro turbines will increase their share of the market because of steady reduction in prices. In this paper the maximal capital costs of decentralized systems are calculated and the nessessary models for simulation of eletricity and heat demand of one-family houses are presented.     

Measurement and modelling of a linear electromagnetic actuator driven camless valve train for spark ignition IC engines under full load condition

Camless engine valve train for gasoline engines particularly port injection engines offer major improvements over traditional system with fixed valve timing and lift, in terms of efficiency, maximum torque and power, and emissions. Electromagnetic driven valve actuators are very promising in this context, but there are significant control problems. The use of displacement sensor could add extra cost to the camless engine. In this work, a moving coil actuator driven valve train was designed and prototyped and a 1D single-cylinder internal combustion engine model was built to investigate the benefit of without throttle by adopting such camless valve train using Ricardo WAVE under full load operating conditions. A novel low-cost sensor named linear actuator position sensor (LAPS) based on flux linkage change on search coil was constructed in LabVIEW by using current, voltage and proximity sensors to detect the valve lift. The measurement of valve lift and current was reported to prove the feasibility of the camless valve train. The valve lift was used for the single-cylinder engine model and the simulation shows that the peak overall engine efficiency using camless valve train reaches 38.2% and the peak torque increases by 5 Nm compared conventional throttled engine under full load operating conditions. The LAPS model was validated by the experimental valve lift and the high accuracy indicates that the LAPS can be adopted for future development of camless valve train for spark ignition IC engines.     

Individual A/F Estimation and Control With the Fuel–Gas Ratio for Multicylinder IC Engines

In internal combustion engines with multicylinders, balancing the air–fuel ratio (A/F) for individual cylinders is an important issue for providing high-quality torque generation and reducing emissions. This paper addresses the individual A/F control problem for a six-cylinder engine with a single sensor. First, a modeling method to estimate the individual fuel–gas ratio, which immediately provides the A/F, is proposed, and using the estimation model, an adaptive generalized predictive control approach to balancing the individual cylinder characteristics is presented, which targets the static engine-operation mode. The effectiveness of the presented model is validated based on the experimental results, and a comparison with existing models is given based on the experiments. Finally, control performance with the proposed individual A/F control approach is demonstrated with the experiments conducted on a six-cylinder engine test bench.      

Measurement of Rocket Engine Spark Gap Ignition EMC

A spark may be used to ignite nonhypergolic rocket engine propellants. Broad-band radiated interference from the spark plug will be radiated through the thrust chamber throat and will limit the level to which interference can be reduced. Tests have been performed by Textron's Bell Aerospace Company to determine the extent to which the rocket engine thrust chamber attenuates radiated interference from the spark. Results indicate that, for small reaction control type engines, compliance with typical EMC specifications is a reasonable possibility.     

Hypersonic flight [scramjet aircraft propulsion]

Current turbojet engines cannot propel an aircraft to hypersonic speeds -their spinning shafts and compressors would simply collapse. To solve this problem, groups in the United States, Japan, Australia, and other countries are working on a propulsion system that burns fuel combined with air flowing at supersonic speeds through the engine, which is essentially a metallic funnel, with no moving parts. These so-called supersonic combustion ramjet (scramjet) engines, outlined in this article, could in theory propel an aircraft to Mach 10 and eventually even more.     

A neural-network based control solution to air-fuel ratio control for automotive fuel-injection systems

Maximization of the catalyst efficiency in automotive fuel-injection engines requires the design of accurate control systems to keep the air-to-fuel ratio at the optimal stoichiometric value AF/sub S/. Unfortunately, this task is complex since the air-to-fuel ratio is very sensitive to small perturbations of the engine parameters. Some mechanisms ruling the engine and the combustion process are in fact unknown and/or show hard nonlinearities. These difficulties limit the effectiveness of traditional control approaches. In this paper, we suggest a neural based solution to the air-to-fuel ratio control in fuel injection systems. An indirect control approach has been considered which requires a preliminary modeling of the engine dynamics. The model for the engine and the final controller are based on recurrent neural networks with external feedbacks. Requirements for feasible control actions and the static precision of control have been integrated in the controller design to guide learning toward an effective control solution.     

A Personalized Search Model Using Online Social Network Data Based on a Holonic Multiagent System

Personalized search utilizes user preferences to optimize search results,and most existing studies obtain user preferences by analyzing user behaviors in search engines that provide click-through data.However,the behavioral data are noisy because users often clicked some irrelevant documents to find their required information,and the new user cold start issue represents a serious problem,greatly reducing the performance of personalized search.This paper attempts to utilize online social network data to obtain user preferences that can be used to personalize search results,mine the knowledge of user interests,user influence and user relationships from online social networks,and use this knowledge to optimize the results returned by search engines.The proposed model is based on a holonic multiagent system that improves the adaptability and scalability of the model.The experimental results show that utilizing online social network data to implement personalized search is feasible and that online social network data are significant for personalized search.     

柴油机共轨电控喷油系统软件设计探析

新能源不断的开发并使用,但石油仍然是21世纪的主要燃料。而内燃机中的共轨电控喷油系统由于它的能柔和燃烧、噪音低、排放量小并且能够实现多次喷射的优点,成为未来内燃柴油机喷油系统的主要研究对象。本文首先介绍了柴油机共轨电控喷油系统的发展历史,然后重点对共轨喷油系统软件开发设计作了探讨说明。     

高功率微波车辆迫停的作用机理及效应试验

通过定量测定车辆电子控制单元喷油控制和点火信号的变化规律,揭示了微波导致发动机熄火的作用机理。试验结果表明,车辆在强电磁脉冲辐射条件下,电子控制单元喷油输出信号发生紊乱,点火信号意外丢失,发动机气缸内混入过量汽油造成火花塞无法点燃油气混合物,导致发动机被迫熄火。     

Detection and Identification of Vehicles Based on Their Unintended Electromagnetic Emissions

When running, vehicles with internal combustion engines radiate electromagnetic emissions that are characteristic of the vehicle. Emissions depend on the electronics, harness wiring, body type, and many other features. Since emissions are unique to each vehicle, these may be used for identification purposes. This paper investigates a procedure for detecting and identifying vehicles based on their RF emissions. Parameters like the average magnitude or standard deviation of magnitude within a frequency band were extracted from measured emission data. These parameters were used as inputs to an artificial neural network (ANN) that was trained to identify the vehicle that produced the emissions. The approach was tested using the emissions captured from a Toyota Tundra, a GM Cadillac, a Ford Windstar, and ambient noise. The ANN was able to classify the source of signals with 99% accuracy when using emissions that captured an ignition spark event     

流化床燃烧技术在东方锅炉厂的发展

对东方锅炉厂流化床锅炉的开发研究历程,特别对流化床锅炉技术方面开展的研究工作和取得的成果作了阐述。并对东方锅炉厂生产的流化床锅炉典型产品的结构特点和运行业绩及其燃用的燃料特性作了简要介绍。