Elimination of Fuel Pressure Fluctuation and Multi-injection Fuel Mass Deviation of High Pressure Common-rail Fuel Injection System

The influence of fuel pressure fluctuation on multi-injection fuel mass deviation has been studied a lot,but the fuel pressure fluctuation at injector inlet is still not eliminated efficiently.In this paper,a new type of hydraulic filter consisting of a damping hole and a chamber is developed for elimination of fuel pressure fluctuation and multi-injection fuel mass deviation.Linear model of the improved high pressure common-rail system（HPCRS）including injector,the pipe connecting common-rail with injector and the hydraulic filter is built.Fuel pressure fluctuation at injector inlet,on which frequency domain analysis is conducted through fast Fourier transformation,is acquired at different target pressure and different damping hole diameter experimentally.The linear model is validated and can predict the natural frequencies of the system.Influence of damping hole diameter on fuel pressure fluctuation is analyzed qualitatively based on the linear model,and it can be inferred that an optimal diameter of the damping hole for elimination of fuel pressure fluctuation exists.Fuel pressure fluctuation and fuel mass deviation under different damping hole diameters are measured experimentally,and it is testified that the amplitude of both fuel pressure fluctuation and fuel mass deviation decreases first and then increases with the increasing of damping hole diameter.The amplitude of main injection fuel mass deviation can be reduced by 73%at most under pilot-main injection mode,and the amplitude of post injection fuel mass deviation can be reduced by 92%at most under main-post injection mode.Fuel mass of a single injection increases with the increasing of the damping hole diameter.The hydraulic filter proposed by this research can be potentially used to eliminate fuel pressure fluctuation at injector inlet and improve the stability of HPCRS fuel injection.

An experimental study on RP-3 jet fuel injection on a common rail injection system

RP-3 jet fuel could be an alternative fuel for diesel engines.In this study,the injection characteristics of RP-3jet fuel under single and split injection strategies were investigated and compared with diesel fuel.The experimental results indicate that RP-3 jet fuel has slightly shorter injection delay time than diesel fuel,but this difference is negligible in actual engine operations.Further,although the lower density and viscosity of RP-3 jet fuel lead to higher volumetric injection rates and cycle-based injection quantities,the cycle-based injection mass and the mass injection rates at the stable injection stage of RP-3 jet fuel are close to or slightly lower than those of diesel fuel.Based on these experimental observations,it could be concluded that fuel physical properties are the secondary factor influencing the injection characteristics in both single and split injection strategies,as RP-3 jet fuel and diesel fuel are taken for comparison.

STRATEGY FOR DIESEL ROTARY ENGINE WITH COMMON RAIL INJECTION SYSTEM

A direct injection low compression ratios diesel rotary engine is designed and studied to find the appropriate application of the electronic controlled high pressure common rail injection system. Current development focuses on the applied fuel injection and ignition strategies, especially concerning the combustion configurations of injectors, ignition source, and combustion chamber. The prototype engine, equipped with Bosch common rail system and high performance electronic control unit （ECU）, is designed correspondingly. Studies show that the integration of a common rail injection system and the main and pilot duel injectors configurations, assisted with glow plug ignition device and flexible ECU, represents a promising approach to improve the potential of the low compression ratios diesel rotary engine. Currently the engine can run at 6 kr · min^-1 steadily and the power is about 68 kW/（4 kr ·min^- 1）.

STRUCTURE PARAMETERS DESIGN AND PERFORMANCE TEST OF FUEL INJECTION SYSTEM

Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.

Design of speed controller for electronic fuel injection gasoline generator based on feed-forward PID control

As for the application of electronic fuel injection （EFI） system to small gasoline generator set, mechanical speed controller cannot be coupled with EFI system and has the shortcomings of lagged regulation and poor accuracy, a feed-forward control strategy based on load combined with proportional-integral-differential （PID） control strategy was proposed, and a digital speed controller applied to the electrical control system was designed. The detailed control strategy of the controller was intro- duced. The hardware design for the controller and the key circuits of motor driving, current sampling and angular signal captu- ring were given, and software architecture was discussed. Combined with a gasoline generator set mounted with EFI system, the controller parameters were tuned and optimized empirically by hardware in loop and bench test methods. Test results show that the speed deviation of generator set is low and the control system is stable in steady state; In transient state the control system responses quickly, has high stability under mutation loads especially when suddenly apply and remove 100% load, the speed deviation is within 8% of reference speed and the transient time is less than 5 s, satisfying the ISO standard.

Design and optimization of a novel electrically controlled high pressure fuel injection system for heavy fuel aircraft piston engine

The heavy fuel compression ignition engines are widely equipped as aircraft piston engines. The fuel injection system is one of the key technologies that determines the performance of engine. One of the main challenges is to precisely control the injected fuel quantity and flow rate in the presence of pressure fluctuation. This challenge is even more serious for heavy fuel. An original design for electrically controlled high pressure fuel injection system called Multi-Pumppressure-reservoirs fuel injection System(MPS) was demonstrated to reduce the pressure fluctuation and help keep injection stable. MPS was compared with an ordinary high pressure Common Rail fuel injection System(CRS). This work established one-dimensional AMESim and mathematical models for both CRS and MPS to study the effect of different structures and geometric parameters on the pressure fluctuations. The calculations show that the average fuel pressure fluctuation of MPS can be reduced by 57% for the crankshaft speed of 1900 r/min, and the pressure fluctuation before injection reduced by 100%. It is concluded that the pressure performance of MPS is less sensitive to pressure reservoir volume than that of CRS, and there is an opportunity for further volume reduction.

Design of Rail Pressure Tracking Controller for Novel Fuel Injection System

This paper proposes a rail pressure tracking controller based on a novel common rail system. A mathematical model, based on physical equations, is developed and used for feed forward control design. Rail pressure peak sampling mechanism is designed to remove the disturbance of rail pressure due to fuel injection. All enhanced tracking differentiator is designed to get smooth tracking signal and exact differential signal from signal with noise. Double loop control strategy is designed to decouple the system and to improve dynamic performance of the system. Experimental results indicate that fluctuation of rail pressure is within il MPa in steady condition, while within ±3 MPa in transient condition, which verifies the effectiveness of the proposed rail pressure control strategy.

Recent Progress in Heavy Fuel Aviation Piston Engine

Heavy fuel aviation piston engines(HF-APEs)refer to the engine using fuels with high flash point,such as kerosene or light diesel.Here technique specifications of some classical foreign HF-APEs(Hirth3503,Zanzottera 498)are introduced.Recent progress and trend of fuel injection,fuel ignition,working cycle,intake charging,thermal management and electronic control of HF-APE are compared and summarized.Emphases are put on the technological difficulties,solutions and development tendency in the design,retrofitting and manufacturing of HF-APE aiming to provide references for the research of related area and the development of prototype HF-APE in China.

基于LabVIEW的比例压力控制阀自动测试系统

根据某公司比例压力控制阀的出厂测试要求,本文设计了一套比例控制阀自动测试系统。该系统基于LabVIEW编程和PLC控制,可实现共轨管稳定的超高压供给,并自动实现比例压力控制阀的耐久测试、流量滞环测试及压力-流量测试,且操作简便,满足企业需求。

双升程电控喷油器多次喷射油量波动特性研究

为实现船用柴油机高压共轨系统喷射的柔性和稳定控制,提出一种双升程电控喷油器,基于搭建的喷油器AMESim仿真模型,探究了喷油器不同多次喷射模式下的油量波动特性.结果表明:大升程预喷模式下的主喷量标准差随预喷量的增加先上升后下降,而小升程预喷模式下的主喷量标准差随预喷量呈幅值逐渐降低的波动变化趋势.总体上,在预喷量为161~660 mm^(3)范围,小升程预喷模式在降低主喷量波动程度方面比大升程预喷模式更占优势.预喷射采用小升程喷射模式且预喷量一定时,升程切换延迟为0.2 ms的靴形主喷模式在降低主喷量波动程度方面略优于相同主喷脉宽或相同单次喷射油量的大升程主喷模式.大升程和小升程后喷模式下的后喷量标准差随主喷脉宽和目标后喷量均呈波动变化趋势,且小升程后喷模式下的后喷量标准差波动程度更小.与大升程后喷模式相比,小升程后喷模式在降低后喷量波动程度方面更占优势.

回油背压对高压共轨喷油器喷油特性影响的研究

高压共轨喷油器是柴油机高压共轨电控系统中最重要的一个部件,其喷油特性(如喷油器量)的优劣将直接影响发动机的性能表现。喷油器的喷射特性不仅受到喷油器的结构参数的影响,同时在喷射过程中还受到外界工作环境的影响,比如喷油器喷射时发动机缸内的背压,以及喷油器工作时的回油通道中的背压。本文主要对某高压共轨喷油器进行台架试验测试,研究喷油器回油背压对喷油特性的影响,并分析产生影响的原因,为开发新型的燃油喷射系统提供试验数据。

喷油特性对F-T煤制油压力振荡影响规律研究

为了减小燃烧噪声,确定影响柴油机高频压力振荡的关键因素,在某型电控高压共轨柴油发动机上燃用的清洁代用燃料Fischer-Tropsch(F-T)煤制油,选取柴油机典型运行工况,研究不同喷油特性条件下柴油机燃烧压力振荡的时域和频域特性。结果表明:推后主喷提前角和提前预喷提前角会使放热率降低,压力振荡幅值减小,气缸压力级也有明显减小的趋势;减小预喷油量会使压力升高率和放热率降低,气缸声压级减小,压力振荡现象减缓,使燃烧更加柔和;提高喷射压力,会使喷油速率增大,燃油雾化效果增强,混合气放热率提升,放热率曲线也随之上升,气缸声压级增大,发动机缸内燃烧压力振荡幅值增大。喷射压力是影响压力振荡的最显著的参数,喷射压力从85MPa上升至115MPa时,压力振荡幅值增加一倍以上;预喷油量对F-T煤制油发动机的燃烧压力振荡影响不显著;同时压力振荡的产生与放热率的变化呈现出较强的相关性。

负荷下19TCI共轨柴油机喷油策略燃烧噪声预测

柴油机工作会产生很大辐射噪声,对其振动辐射噪声控制技术的研究是目前的一个热点。根据声学本质等效成线性传递形式,实现了燃烧噪声传递函数的线性化处理。选择19TCI电控共轨柴油机开展测试,结合喷油控制方案以及实际负荷特征建立噪声传递函数并寻优,对负荷传递函数开展评价。研究结果表明:不同转速传递函数满足负荷一致性验证,能够满足精度控制要求。该研究有助于提高柴油机燃烧效率,也可拓宽到其他热能设备上,具有很宽的应用价值。

基于可变喷油规律的设计分析

为优化轻重型柴油机的燃烧效率以及满足严格的排放法规,提出一种基于双喷油器的可变喷油规律构想。利用Simulink搭建喷油器执行驱动仿真模型,并在发动机仿真台架中进行仿真验证。研究结果表明,通过控制双喷油器开始喷射时刻以及喷射持续时间,可实现方形、斜坡形、靴型和反斜坡形等不同形式的喷油规律。其中,喷油控制策略可对主喷实现靴型、方形、斜坡与反斜坡形、预喷实现斜坡形、后喷实现方形喷油规律,最终通过构建多种喷油规律未来可实现不同工况下的最优喷油规律。

Introduction to the benchmark challenge on common rail pressure control of gasoline direct injection engines

As one of the most important actuators for gasoline direct injection technology,common rail systems provide the requested rail pressure for fuel injection.Special system characteristics,such as coupled discrete-continuous dynamic in the common rail system,limited measurable states,and time-varying engine operating conditions,impel the combination of advanced methods to obtain the desired injection pressure.Therefore,reducing the pressure fluctuation and satisfying engineering implementation have become noteworthy issues for rail pressure control(RPC)systems.In this study,the benchmark problem and the design specification of RPC proposed by 2018 IFAC E-CoSM Committee are introduced.Moreover,a common rail system model is provided to the challengers,and a traditional PI control is applied to show the problem behaviors.Finally,intermediate results of the challengers are summarized briefly.

进出油阀参数对高压供油泵流量的影响分析

基于共轨燃油喷射系统高压供油泵模型,研究了进出油阀参数对高压供油泵流量的影响,结果表明:进油阀弹簧预紧力的大小对高压供油泵流量影响很大,过大或过小都会使高压供油泵流量减小;进油阀阀孔直径、升程过小会造成进油节流,使高压供油泵流量减小;进油阀阀芯质量过大会使高压供油泵高转速流量减小;出油阀阀芯质量过大会造成高压供油泵流量波动。

高压共轨柴油机EGR控制策略分析

阐述高压共轨柴油机电控EGR控制作用与原理,探索有效的EGR控制策略,包括开环控制、双闭环控制、EGR阀控制和基于工况的EGR控制,从而降低废气污染物排放量,优化发动机性能。

基于红嘴蓝鹊算法的高压共轨燃油喷射控制研究

文章针对柴油机高压共轨系统燃油喷射精确度不高的问题,提出一种基于红嘴蓝鹊算法的高压共轨燃油喷射控制方法。首先,对高压共轨燃油喷射系统进行数学建模;其次,构建一套柴油机高压共轨燃油喷射控制系统,该系统利用模糊PID算法实现对燃油喷射的控制;在此基础上,针对模糊PID控制算法中的模糊论域,运用红嘴蓝鹊算法进行优化。最后,利用MATLAB/Simulink对传统PID、模糊PID和基于红嘴蓝鹊算法的模糊PID控制算法这三者进行仿真对比。研究结果表明,经红嘴蓝鹊算法优化后,燃油喷射量的控制更加精确,可以有效提升高压共轨燃油喷射系统的性能。

一种共轨式电控柴油机的燃油喷射系统

研究开发了一种共轨式柴油机的电喷系统 ,设计了系统的硬件和软件并在油泵试验台上对系统进行了性能试验。由试验可知 :( 1)电控喷油器的响应速度快 ,完成一次喷油的最短时间为 0 .9ms;( 2 )喷油正时及喷油量随工况的变化关系控制灵活 ,调节范围大 ,喷油量的喷油持续角可控范围为 4°～ 50°油泵轴转角 ,喷油正时的可控范围可达± 3 0°油泵轴转角 ;( 3 )系统整体的控制精度高 ,喷油正时及喷油脉宽的理论控制误差均小于 0 .0 9°油泵轴转角 ;( 4)系统的喷射压力可在 0 MPa～ 4 5MPa之间连续调节 ,误差小于 5%。

一种用于液化燃料的电控共轨式喷射系统

介绍了一种新的电控共轨式燃油喷射系统。该系统根据各种液化代用燃料的特殊性质,采用电子控制技术和共轨式喷射原理,能够满足多种液化代用燃料在发动机上应用的要求。同时研究了这种系统的喷射特性,并以柴油为燃料进行了发动机台架试验,验证了系统的可行性。