《小型汽油机振动测试方法》试验方法的讨论

标准GB/T 10398-1989《小型汽油机振动测试方法》提出了小型通用汽油机振动的试验方法,但是未规定振动测试设备参数的设置。在试验中,仪器参数的设置对试验结果有着重要的影响。通过相关理论及实际的试验分析了仪器参数设置对试验结果的影响,并提出相应的解决方法。     

分层扫气技术在小型二冲程汽油机上的应用

本文为应对欧洲、美国的汽油机排放法规,提出一种分层扫气技术,利用这项技术,可以最大限度降低小型二冲程汽油机在扫气时未燃烧混合气的短路损失和提高燃烧效率,从而实现减少汽油机的HC和NOx排放指标的目的,并能大幅降低汽油机燃油消耗率,达到使小型二冲程汽油机即环保又节能的目的,为小型二冲程汽油机进入欧美市场扫清技术障碍。     

缸内直接喷射式汽油机点火稳定性的数值分析

缸内直接喷射式汽油机的一个显著特点是依靠火花塞点燃喷入缸内的汽油油束。由于缸内混合气浓度极不均匀，所以其点火及火焰传播过程与普通均质燃烧式发动机有很大的不同。火焰核心的稳定形成及初始火焰发展对缸内的整个燃烧过程有极其重要的影响。本文利用二维两相混合模型模拟喷雾过程，利用一个详细的准维模型模拟火花塞的点火过程，并采用特殊处理方法使两个子模型相匹配，计算了缸内直接喷射式汽油机从喷雾到形成稳定火核的全过程，分析了多种因素对点火稳定性的影响，尤其是对涡流比、点火时刻和喷油定时之间的适当配合进行了模拟分析。计算结果对优化实验有明显的指导作用。     

A new approach to deep desulfurization of gasoline by electrochemically catalytic oxidation and extraction

In order to further reduce the sulfur content in gasoline, a new desulfurization process for gasoline was obtained by means of electrochemically catalytic oxidation and extraction with an electrochemical fluidized-bed reactor. The particle group anode was activated carbon-supported lead dioxide (β-PbO₂/C). The electrolyte was aqueous NaOH solution, and copper pillar was cathode in the electrochemical reactions. The β-PbO₂/C particle group anodes can remarkably accelerate the electrochemical reaction rate and promote the electrochemical catalysis performance for the electrochemical desulfurization reaction. Also, gasoline desulfurization rule was investigated in an alkali solution. The experimental results indicated that the optimal desulfurization conditions were as follows: the cell voltage, the pH value of the electrolyte, feed volume flow rate and the β-PbO₂ percentage by weight were 3.2 V, pH value 13.1, 300 ml min^{− 1} and 5.0 wt.%, respectively. Under these conditions the concentration of sulfur in gasoline was reduced from 310 to 40 μg g^{− 1}, and the main properties of the product were not significantly affected. Based on these experimental results, a mechanism of indirect electrochemical oxidation was proposed.     

汽油烃组成对汽车排放的影响

使用不同烃组成的6种汽油分别在满足国III、国IV排放标准的车型上进行了I型、IV型和VI型排放试验,研究了汽油烯烃、芳烃含量对常温冷启动后、低温冷启动后尾气排放和蒸发排放的影响。结果表明,汽油组成对排放的影响与汽车技术密切相关,满足国IV排放标准的车型上,当芳烃体积分数为35%、油品烯烃体积分数控制在25%时,HC,CO,NOx三种排放物较低;芳烃含量对排放的影响与发动机技术相关,但基本上呈现出芳烃含量较低时排放也较低的趋势;总蒸发排放物随油品烯烃含量增加而增加;油品的非烷烃类烃含量（即烯烃含量与芳烃含量之和）越高,车辆低温冷起动后HC、CO排放越高。     

COMPOSITIVE EMISSION CONTROL SYSTEM OF GASOLINE VEHICLE

The working principle of a kind of compositive emission control system is inquired into, which includes exhaust heater, secondary air supplement, exhaust gas recirculation (EGR), thermal reactor and catalytic converter, etc. The purification effect of CO, HC and NOx emission of the gasoline spark ignite (S.I.) engine is studied. The entire vehicle driving cycle tests based on the national emission standard and a series of the gasoline engine-testing bench tests including full load characteristic experiment, load characteristic experiment and idle speed experiment are done. The results show that the system has a very good emission control effect to CO, HC and NOx of gasoline engine. The construction of the system is very simple and can be mounted on the exhaust pipe conveniently without any alteration of the vehicle-use gasoline engine.     

Receding horizon online optimization for torque control of gasoline engines

This paper proposes a model-based nonlinear receding horizon optimal control scheme for the engine torque tracking problem. The controller design directly employs the nonlinear model exploited based on mean-value modeling principle of engine systems without any linearizing reformation, and the online optimization is achieved by applying the Continuation/GMRES (generalized minimum residual) approach. Several receding horizon control schemes are designed to investigate the effects of the integral action and integral gain selection. Simulation analyses and experimental validations are implemented to demonstrate the real-time optimization performance and control effects of the proposed torque tracking controllers.     

The association between price of regular-grade gasoline and injury and mortality rates among occupants involved in motorcycle- and automobile-related motor vehicle collisions

Motorcyclists have been reported to be more likely to die in a motor vehicle collision (MVC) than automobile occupants. With the recent increase in the pump price of gasoline, it has been reported that people are switching to motorcycles as main modes of transportation. This study evaluated the association between motor vehicle collision-related injury and mortality rates and increases in gasoline prices for occupants of automobiles and riders of motorcycles.There were an estimated 1,270,512 motorcycle MVC and 238,390,853 automobile MVC involved occupants in the U.S. from 1992 to 2007. Higher gasoline prices were associated with increased motorcycle-related injuries and deaths; however, this association no longer remained after accounting for changes in the number of registered vehicles.The current study observed that, while the number of injuries and fatalities in motorcycle-related MVCs increase with increasing gasoline price, rates remained largely unchanged. This suggests that the observed increase in motorcycle-related injuries and fatalities with increasing gasoline price is more a factor of the number of motorcycles on the road rather than operator characteristics.     

Experimental investigation of Gasoline-Like Fuel obtained from waste lubrication oil on engine performance and exhaust emission

Experimental investigation on engine performance and exhaust emission of a gasoline engine fueled by Gasoline-Like Fuel (GLF) was performed in this study. The GLF was obtained from waste lubrication oil (WLO) using the pyrolitic distillation method. Firstly, the WLO collected in a tank was particulates removed by a refining process. The refined lubrication oil samples were taken into a reactor and blended with calcium oxide (CaO) 2, 4, 6, 8, and 10 wt.% to remove sulphur in the oil. The blended samples were heated in the reactor and then distilled to decrease sulphur and to produce fuel samples. Distillation tests and characteristics of the produced fuel such as density, flash point and lower heating value were examined. The experimental results indicated that the CaO at 2 wt.% had the highest effect on decreasing the amount of sulphur content in the lubrication oil. Fuels produced using 2 wt.% CaO were separated into two parts which were light fuel with 20 wt.% and heavy fuel with 60 wt.% of the total WLO. Remaining of the WLO is about 20 wt.%, which is rejected from the reactor. The light fuel, referred to as GLF and gasoline samples are used to investigate the effect of the GLF on performance and emissions of a 1300 cm³ spark ignited engine manufactured by Fiat. The engine used in the study has specifications of four-stroke and four cylinders, water cooled, fueled with carburetor and naturally aspirated. Each cylinder has a bore of 76 mm and a stroke of 71.5 mm. The experimental results showed that the GLF had a positive effect on brake power, brake thermal efficiency, mean effective pressure and specific fuel consumption. The GLF also raised CO emission and exhaust temperature, but it decreased hydrocarbon (HC) in the exhaust.     

Air exchange rates and migration of VOCs in basements and residences

Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs, and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady‐state multitracer system, and 7‐day VOC measurements were collected using passive samplers in both living areas and basements. A walk‐through survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52/h, respectively, and had strong and opposite seasonal trends, for example, AERs were highest in residences during the summer, and highest in basements during the winter. Airflows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right‐skewed, for example, 90th percentile benzene, toluene, naphthalene, and limonene concentrations were 4.0, 19.1, 20.3, and 51.0 μg/m³, respectively; maximum concentrations were 54, 888, 1117, and 134 μg/m³. Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline‐powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements.