运转参数对双燃烧发动机性能影响的预测

文中模拟计算了运转参数如进气温度，喷油定时等对双燃料发动机性能的影响，简要分析了改善发动机性的措施。结果表明，燃用双燃料需适当提前喷油；而缸内存适当涡流，有益于提高输出功率。     

R6160船用双燃料发动机的性能仿真与优化研究

针对改进型双燃料发动机燃烧效果较差的问题,采用一维仿真的方法,建立了R6160双燃料发动机模型。应用此模型研究了喷油正时、天然气喷气正时和过量空气系数对燃烧的影响;对喷油正时和天然气喷气正时的改进效果进行了试验验证。试验结果表明:合理调整喷油正时和天然气喷气正时能有效改进双燃料发动机的性能。     

LPG-柴油双燃料发动机排放及动力特性的研究

对发动机燃用LPG(液化石油气)-柴油双燃料时,喷油提前角的变化对发动机有害排放物数量和动力性能的影响进行了研究。试验结果表明:喷油提前角为7°左右时,双燃料发动机的综合排放性能最好,碳烟的排放水平较原发动机有明显的降低,同时发动机功率没有出现太大的损失。     

双燃料发动机(天然气/柴油)性能与排放的研究

以4102型柴油机为基础机，开发天然气／柴油双燃料发动机，试验研究引燃油量、喷油提前角对发动机排放和经济性影响，以及双燃料发动机与原柴油机性能和排放的比较。     

柴油/天然气电控双燃料技术研究

针对双燃料发动机的特点介绍了电控双燃料系统的原理;并对所研究的双燃料发动机的失效模式及效应进行了分析。性能试验表明:在不对原柴油机喷油角度、压缩比等参数进行任何改动,只增加燃气供应系统和电控双燃料系统的情况下,在75%负荷下天然气的替代率达到83%,经济性好;同时,排放较纯柴油有较大的改善;发动机的排温、最高燃烧压力及调速性能与柴油机的相近。     

引燃柴油喷油正时对LNG-柴油双燃料发动机燃烧特性的影响

以一台涡轮增压六缸柴油机改造的发动机为试验对象,研究引燃柴油喷油正时对LNG-柴油双燃料发动机燃烧特性的影响。研究了不同喷油正时下的双燃料发动机的缸内压力、压力升高率、缸内温度、燃烧放热规律、循环变动等参数。研究结果表明:引燃柴油喷油正时对双燃料发动机燃烧特性影响很大。随引燃柴油喷油正时的增大,最高缸内压力、最高压力升高率、最大燃烧温度和最大瞬时放热率先升高后降低且所对应的曲轴转角减小;峰值压力循环变动系数先降低后增大,峰值压力升高率循环变动系数降低。     

喷油对发动机混合气分配及性能影响的研究

本文研究了电控单点汽油喷射发动机喷油间隔和喷油定时对发动机各缸混合气分配及其性能的影响，试验结果表明：喷油间隔和喷油定时对混合气分配及发动机性能有很大的影响，适当的喷油间隔可以减小喷油定时的影响；研究过程中发现，进气压力（反映负荷状况）对混合气分配也有明显的影响。     

喷油对发动机混合气分配及性能影响的研究

本文研究了电控单点汽油喷射发动机喷油间隔和喷油定时对发动机各缸混合气分配及其性能的影响，试验结果表明：喷油间隔和喷油定时对混合气分配及发动机性能有很大的影响，适当的喷油间隔可以减小喷油定时的影响，研究过程中发现，进气压力（反映负荷状况）对混合气分配也有明显的影响。     

预测运转参数对双燃料发动机性能的影响

文中模拟计算了运转参数如引燃油量、燃料当量比等对双燃料发动机性能的影响 ,简要分析了改善发动机性能的措施。结果表明 ,适当增加燃料当量比有益于提高输出功率     

预测运转参数对双燃料发动机性能的影响

文中模拟计算了运转参数如引燃油量,燃料当量比等对双燃料发动机性能的影响,简要介绍了改善发动机性能的措施。结果表明,适当增加燃料当量比有益于提高输出功率。     

Improving the performance of dual fuel engines running on natural gas/LPG by using pilot fuel derived from jojoba seeds

The use of jojoba methyl ester as a pilot fuel was investigated for almost the first time as a way to improve the performance of dual fuel engine running on natural gas or liquefied petroleum gas (LPG) at part load. The dual fuel engine used was Ricardo E6 variable compression diesel engine and it used either compressed natural gas (CNG) or LPG as the main fuel and jojoba methyl ester as a pilot fuel. Diesel fuel was used as a reference fuel for the dual fuel engine results. During the experimental tests, the following have been measured: engine efficiency in terms of specific fuel consumption, brake power output, combustion noise in terms of maximum pressure rise rate and maximum pressure, exhaust emissions in terms of carbon monoxide and hydrocarbons, knocking limits in terms of maximum torque at onset of knocking, and cyclic variability data of 100 engine cycles in terms of maximum pressure and its pressure rise rate average and standard deviation. The tests examined the following engine parameters: gaseous fuel type, engine speed and load, pilot fuel injection timing, pilot fuel mass and compression ratio. Results showed that using the jojoba fuel with its improved properties has improved the dual fuel engine performance, reduced the combustion noise, extended knocking limits and reduced the cyclic variability of the combustion.     

Combustion characteristics and performance of natural gas in high speed indirect injection diesel engine

In recent years, efforts have been directed towards environmentally freindly sources of alternative fuels for internal combustion engines. This paper investigates combustion characteristics and performance of natural gas in an unmodified compression ignition engine using diesel fuel pilot injection. The factors influencing knock limits in dual fuel gas engines have been identified. This report is confined to experimental work in a naturally aspirated dual gas engine and the results obtained were compared with the diesel fueled test engine. Cylinder pressure diagrams recorded indicate longer ignition delay and burning rates with an increased pressure variation.     

双燃料发动机燃烧模型的研究与应用

以天然气为主要燃料、少量柴油机为引燃油的双燃料发动机为研究对象,建立模型,它包括热力学、经学反应动力学、引燃油多区传热和燃烧模型。应用该模型预算了双燃料发动机的燃烧过程,分析了运行和结构参数对双燃料发动机性能和排放的影响。     

A renewable pathway towards increased utilization of hydrogen in diesel engines

In the present work, dual fuel operation of a diesel engine has been experimentally investigated using biodiesel and hydrogen as the test fuels. Jatropha Curcas biodiesel is used as the pilot fuel, which is directly injected in the combustion chamber using conventional diesel injector. The main fuel (hydrogen) is injected in the intake manifold using a hydrogen injector and electronic control unit. In dual fuel mode, engine operations are studied at varying engine loads at the maximum pilot fuel substitution conditions. The engine performance parameters such as maximum pilot fuel substitution, brake thermal efficiency and brake specific energy consumption are investigated. On emission side, oxides of nitrogen, hydrocarbon, carbon monoxide and smoke emissions are analysed. Based on the results, it is found that biodiesel-hydrogen dual fuel engine could utilize up to 80.7% and 24.5% hydrogen (by energy share) at low and high loads respectively along with improved brake thermal efficiency. Furthermore, hydrocarbon, carbon monoxide and smoke emissions are significantly reduced compared to single fuel diesel engine operation. Exhaust gas recirculation (EGR) has also been studied with biodiesel-hydrogen dual fuel engine operations. It is found that EGR could improve the utilization of hydrogen in dual fuel engine, especially at the high loads. The effect of EGR is also found to reduce high nitrogen oxide emissions from the dual fuel engine and brake thermal efficiency is not significantly affected.     

Pressure–time characteristics in diesel engine fueled with natural gas

Combustion pressure data are measured and presented for a dual fuel engine running on dual fuel of diesel and compressed natural gas, and compared to the diesel engine case. The maximum pressure rise rate during combustion is presented as a measure of combustion noise. Experimental investigation on diesel and dual fuel engines revealed the noise generated from combustion in both cases. A Ricardo E6 diesel version engine is converted to run on dual fuel of diesel and compressed natural gas and is used throughout the work. The engine is fully computerized and the cylinder pressure data, crank angle data are stored in a PC for off-line analysis. The effect of engine speeds, loads, pilot injection angle, and pilot fuel quantity on combustion noise is examined for both diesel and dual engine. Maximum pressure rise rate and some samples of ensemble averaged pressure–crank angle data are presented in the present work. The combustion noise, generally, is found to increase for the dual fuel engine case as compared to the diesel engine case.     

柴油、天然气双燃料发动机的燃烧特性分析

研究了柴油,天然气双燃料发动机的燃烧特性,并着重分析了引燃柴油供给系统参数对双燃料发支持性的影响。以试验为基础,首先简要比较了柴油,天然气双燃料发动机与柴油机的燃烧特性,并对比了负荷对双燃料发动机燃烧特性的影响。然后分析了最小循环喷油量,引燃柴油量,引燃油喷射压力,喷嘴参数及供油提前角等引燃柴油供给系统参数对最高爆发压力,燃烧放热率,着火开始时间、累积燃烧放热率等柴油,天然气双燃料发动机燃烧特性的     

基于微遗传算法的船用柴油机喷油策略优化及研究

为优化大型船用柴油机的燃油喷射策略,采用微种群遗传算法结合三维数值模拟,在一台大缸径低速船用柴油机上对两个喷油器的主喷时刻、预喷间隔和预喷比例进行了优化,并在优化算例的基础上研究了大型船用柴油机各个喷油器预喷参数和顺序喷射对性能与排放的影响。研究结果表明,在采用顺序喷射的前提下,顺序喷射间隔影响NOx排放和指示燃油消耗率。第一个和第二个喷油器的预喷策略对大型船用柴油机的性能与排放有不同的影响,前者是预喷放热与主喷滞燃期缩短综合作用的结果,而后者主要是预喷放热自身的影响。通过以上研究和优化,柴油机的NOx排放降低了21.27%,表明该方法可以用于优化大型船用柴油机的喷射策略。     

Effect of pilot fuel injection pressure and injection timing on combustion,performance and emission of hydrogen-biodiesel dual fuel engine

The present study highlights the influence of fuel injection pressure (FIP) and fuel injection timing (FIT) of Jatropha biodiesel as pilot fuel on the performance, combustion and emission of a hydrogen dual fuel engine. The hydrogen flow rates used in this study are 5lit/min, 7lit/min, and 9lit/min. The pilot fuel is injected at three FIPs (500, 1000, and 1500 bar) and at three FITs (5°, 11°, and 17?bTDC). The results showed an increase in brake thermal efficiency (B_th)from 25.02% for base diesel operation to 32.15% for hydrogen-biodiesel dual fuel operation with 9lit/min flow rate at a FIP of 1500 bar and a FITof17?bTDC. The cylinder pressure and heat release rate (HRR) are also found to be higher for higher FIPs. Advancement in FIT is found to promote superior HRR for hydrogen dual fuel operations. The unburned hydrocarbon (UHC) and soot emissions are found to reduce by 59.52% and 46.15%, respectively, for hydrogen dual fuel operation with 9lit/min flow rate at a FIP of 1500 bar and a FIT of 11?bTDC. However, it is also observed that the oxides of nitrogen (NO_X) emissions are increased by 20.61% with 9lit/min hydrogen flow rate at a FIP of 1500 bar and a FIT of 17?bTDC. Thus, this study has shown the potential of higher FIP and FIT in improving the performance, combustion and emission of a hydrogen dual fuel engine with Jatropha biodiesel as pilot fuel.     

Ignition delay of dual fuel engine operating with methanol ignited by pilot diesel

An investigation on the ignition delay of a dual fuel engine operating with methanol ignited by pilot diesel was conducted on a TY1100 direct-injection diesel engine equipped with an electronic controlled methanol low-pressure injection system. The experimental results show that the polytropic index of compression process of the dual fuel engine decreases linearly while the ignition delay increases with the increase in methanol mass fraction. Compared with the conventional diesel engine, the ignition delay increment of the dual fuel engine is about 1.5° at a methanol mass fraction of 62%, an engine speed of 1600 r/min, and full engine load. With the elevation of the intake charge temperature from 20°C to 40°C and then to 60°C, the ignition delay of the dual fuel engine decreases and is more obvious at high temperature. Moreover, with the increase in engine speed, the ignition delay of the dual fuel engine by time scale (ms) decreases clearly under all engine operating conditions. However, the ignition delay of the dual fuel engine increases remarkably by advancing the delivery timing of pilot diesel, especially at light engine loads.