柴油机机油耗的模拟分析

在应用ANSYS软件计算得到活塞和缸套变形的基础上,应用GLIDE软件对不同活塞、活塞环和缸套组合的机油耗进行了计算与分析,计算结果表明:选择合适的活塞环可以有效地降低整个转速区域内的机油耗,加强活塞的冷却和采用椭圆形缸套均可降低发动机高速时的机油耗.     

浅谈活塞环对发动机机油耗的影响

通过对发动机油耗影响因素的分析,说明活塞环在控制机油耗方面起到至关重要的作用。     

国Ⅳ重型柴油机降机油耗技术探讨

随着我国对排放要求不断提高,部分大城市开始实施国Ⅳ排放：如北京,上海等。针对我国实际情况采用SCR技术达国4排放要求是我国众多发动机厂采用的主流技术。但由于国4排放中对颗粒的要求只有国3颗粒的1/5：机油消耗中约有1/10转换为颗粒排放出来。那么如何降低机油耗成为能否采用该技术的关键。本文就是介绍如何对活塞、活塞环、气缸套及气缸体等相关零部件进行设计改进达到国4重型柴油机机油耗要求的。     

影响单缸柴油机机油耗的因素及分析

以单缸蒸发冷却式柴油机为例,分析柴油机机油耗测试过程存在的各种影响因素及减少测试误差的措施。     

某V型发电柴油机机油耗高问题分析及改进

针对某V型发电柴油机机油耗过高的情况,采用仿真及试验的手段,确定了机油消耗量大的主要原因,明确了降低活塞温度、优化活塞环组运动、增强控油能力的优化方向。通过优化改进气缸套网纹、活塞内冷油道结构和活塞环组尺寸,优化活塞、活塞环和缸套的配合间隙,增加刮碳环,实现了对活塞环组降温、顺气、控油和及时清除积碳的效果,达到降低柴油机机油耗的目的,改进方案经市场验证效果良好。     

柴油机机油耗高的排查改进及控制

介绍了柴油机机油消耗高的排查方法,通过对机油消耗率影响因素的分析,进行试验和测量,提出了设计改进措施和质量控制措施,使柴油机机油消耗率得到了进一步降低,同时也促进了柴油机的环保排放达标。     

发动机下排气量大、机油耗高和断环问题的分析及改进

本文主要对某柴油机出现下排气量大、机油耗高及断环等问题的分析,通过对活塞环、活塞及缸套摩擦副的改进设计及试验验证,提出了＂下排气量大＂、＂机油耗高＂、＂断环＂、＂拉缸＂等问题的改进方案.     

机油耗高、下排气大、断环的失效分析及改进

本文叙述了某柴油机机油油耗高、下排气大和断环的调研、分析、改进及验证.同时指出柴油机和汽车的配套设计及质量控制的重要性.     

柴油机机油外来污染物——烟炱的分析

柴油机机油外来污染物之一是柴油燃烧过程形成的烟炱,过多的烟炱含量不仅缩短柴油机机油的寿命,而且增加零部件的磨损.本文重点对使用过程中的旧油进行红外光谱测试,分析烟炱对粘度增长的影响.     

YHY-1型内燃机车柴油机油耗仪

YH-1型油耗仪采用89C52单片机对流量及温度传感器输出信号进行处理,大大简化了油耗仪的硬件结构,提高了精度及可靠性.油耗仪测量精度能满足机务段机车检修工作的需要,同时具有结构简单、使用方便、造价低、测量时间短等特点.     

Performance of direct-injection off-road diesel engine on rapeseed oil

This article presents the comparative bench testing results of a naturally aspirated, four stroke, four cylinder, water cooled, direct injection Diesel engine operating on Diesel fuel and cold pressed rapeseed oil. The purpose of this research is to study rapeseed oil flow through the fuelling system, the effect of oil as renewable fuel on a high speed Diesel engine performance efficiency and injector coking under various loading conditions.Test results show that when fuelling a fully loaded engine with rapeseed oil, the brake specific fuel consumption at the maximum torque and rated power is correspondingly higher by 12.2 and 12.8% than that for Diesel fuel. However, the brake thermal efficiency of both fuels does not differ greatly and its maximum values remain equal to 0.37–0.38 for Diesel fuel and 0.38–0.39 for rapeseed oil. The smoke opacity at a fully opened throttle for rapeseed oil is lower by about 27–35%, however, at the easy loads its characteristics can be affected by white coloured vapours.Oil heating to the temperature of 60 °C diminishes its viscosity to 19.5 mm² s⁻¹ ensuring a smooth oil flow through the fuel filter and reducing the brake specific energy consumption at light loads by 11.7–7.4%. Further heating to the temperature of 90 °C offers no advantages in terms of performance. Special tests conducted with modified fuel injection pump revealed that coking of the injector nozzles depends on the engine performance mode. The first and second injector nozzles that operated on pure oil were more coated by carbonaceous deposits than control injector nozzles that operated simultaneously on Diesel fuel.     

运用中柴油机油的分析及化验意义

分析了柴油机油在使用过程中的污染变质问题,说明运用中柴油机油化验分析的意义,并提出实际应用中存在的问题及建议。     

Performance of jatropha oil blends in a diesel engine

Results are presented on tests on a single-cylinder direct-injection engine operating on diesel fuel, jatropha oil, and blends of diesel and jatropha oil in proportions of 97.4%/2.6%; 80%/20%; and 50%/50% by volume. The results covered a range of operating loads on the engine. Values are given for the chemical and physical properties of the fuels, brake specific fuel consumption, brake power, brake thermal efficiency, engine torque, and the concentrations of carbon monoxide, carbon dioxide and oxygen in the exhaust gases. Carbon dioxide emissions were similar for all fuels, the 97.4% diesel/2.6% jatropha fuel blend was observed to be the lower net contributor to the atmospheric level. The trend of carbon monoxide emissions was similar for the fuels but diesel fuel showed slightly lower emissions to the atmosphere. The test showed that jatropha oil could be conveniently used as a diesel substitute in a diesel engine. The test further showed increases in brake thermal efficiency, brake power and reduction of specific fuel consumption for jatropha oil and its blends with diesel generally, but the most significant conclusion from the study is that the 97.4% diesel/2.6% jatropha fuel blend produced maximum values of the brake power and brake thermal efficiency as well as minimum values of the specific fuel consumption. The 97.4%/2.6% fuel blend yielded the highest cetane number and even better engine performance than the diesel fuel suggesting that jatropha oil can be used as an ignition-accelerator additive for diesel fuel.     

Performance of rapeseed oil blends in a diesel engine

The concept that 100% vegetable oil cannot be used safely in a direct-injection diesel engine for long periods of time has been stressed by many researchers. Short-term engine tests indicate good potential for vegetable oil fuels. Long-term endurance tests may show serious problems in injector coking, ring sticking, gum formation, and thickening of lubricating oil. These problems are related to the high viscosity and nonvolatility of vegetable oils, which cause inadequate fuel atomization and incomplete combustion. Fuel blending is one method of reducing viscosity. This paper presents the results of an engine test on three fuel blends. Test runs were also made on neat rapeseed oil and diesel fuel as bases for comparison. There were no significant problems with engine operation using these alternative fuels. The test results showed increases in brake thermal efficiency as the amount of rapeseed oil in the blends increases. Reduction of power-output was also noted with increased amount of rapeseed oil in the blends. Test results include data on performance and gaseous emissions. Crankcase oil analyses showed a reduction in viscosity. Friction power was noted to increase as the amount of diesel fuel in the blend increases.     

铁路内燃机车柴油机油烟炱含量的测量

介绍了近年来柴油机的发展及评定项目、几种烟炱的测定方法以及铁路柴油机油烟炱含量的测试。     

Combustion characteristics of a diesel engine operated with diesel and burning oil of biomass

In this study, burning oil of biomass (BOB) was derived from biomass corncob tar by distillation. The fuel BOB1 was extracted from biomass corncob tar by distilling temperature range from 110 to 220 °C, the fuel BOB2 was extracted from biomass corn tar by distilling temperature over 220 °C. This paper presents that the results in the physical characteristic of BOB as an alternative fuel and a comparative control experiences in unmodified diesel engine. Engine power performance, fuel consumption and emissions (CO₂, CO, HC and NO) have been studied. There was no significant difference in performance between diesel fuel and mixed fuel. The mixed fuel operation produced low fuel consumption at the various loading. Mixed fuel 1 (mixed 10% BOB1 with diesel by volume) and mixed fuel 2 (mixed 10% BOB2 with diesel by volume) with 11.7 and 6.6% oil-economizing rate, had better oil-economizing compare to diesel fuel respectively. The mixed fuel 1 and mixed fuel 2 showed significant improvement at CO₂ emissions.     

Study on cottonseed oil as a partial substitute for diesel oil in fuel for single-cylinder diesel engine

The experiments were undertaken to obtain the knowledge necessary for raising the thermal efficiency of mixed oil composed of cottonseed oil and conventional diesel oil and for improving the performance of engine fuelled by the mixture. The experimental results obtained showed that a mixing ratio of 30% cottonseed oil and 70% diesel oil was practically optimal in ensuring relatively high thermal efficiency of engine, as well as homogeneity and stability of the oil mixture. A quadratic regressive orthogonal design test method was adopted in the experiment designed to examine the relationship between specific fuel consumption and four adjustable working parameters (intake-valve-closing angle (α), exhaust-valve-opening angle (β), fuel-delivery angle (θ) and injection pressure (P, in 10⁴ Pa)) when the above-mentioned oil mixture was used. The mathematical equations characterizing the relationship were formulated. The equation of specific fuel consumption derived from the regressive test under each operating condition was set as the objective function and the ranges for the four adjustable working parameters were the given constraint condition. Models of non-linear programming were then constructed. Computer-aided optimization of the working parameters for 30:70 cottonseed oil/diesel oil mixed fuel was achieved. It was concluded that the predominant factor affecting the specific fuel consumption was fuel-delivery angle θ, the approximate optimal value of which, in this specific case, was 3–5° in advance of that for engine fuelled by pure diesel oil. The experimental results also provided useful reference material for selection of the most preferable combination of working parameters.     

DF8B型机车柴油机费水原因的判断与维修

1 概述 DF8B型机车柴油机冷却系统由高温、低温两个部分组成。高温水系统用于冷却气缸套、气缸盖和增压器;低温水系统用于冷却增压器压气机出来的增压空气。如果冷却水系统发生故障（如循环不畅、漏水、烧水等）,将导致柴油机主要部件（如气缸盖、活塞、气缸套、气门、喷油器等）过热,使其机械性能下降,产生严重热应力,导致变形和裂纹,高温也将引起机油物理化学性能变坏和结焦,使其失去润滑性能,最后导致拉缸、零件咬死、断裂等,高温还会引起空气充量下降而使燃烧不充分,影响柴油机的性能。因此,良好的冷却系统是柴油机正常工作的必要条件。