共查询到20条相似文献,搜索用时 125 毫秒
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针对某型车辆发动机实车进气流量难以测量的问题,通过分析发动机进气系统结构,对气体流动过程进行简化处理.基于气体总流伯努利方程,建立发动机进气流量计算模型,采用空气滤清器台架阻力试验数据对模型进行完善与验证,误差小于2%,并对车辆原位空转及驾驶训练过程进行了测试,进气流量计算结果与实际状况相符. 相似文献
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建立了摩托车发动机缸体与水套流固耦合传热仿真模型,进行了流体与固体之间的共轭传热仿真。结果表明,水套对缸体的散热效果基本满足散热要求;但缸体缸套区域水套内的冷却水流速分布较差,存在比较大范围的漩涡和流动死区,导致缸套局部过热,周向温差过大,为此对分水孔进行了优化设计,基本消除了流动死区,显著提高了水套冷却效能,缸体主要区域的温度显著减低,缸套局部过热也得到很大缓解。 相似文献
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Kyoung Suk Park Jong Phil Won Hyung Seok Heo 《Journal of Mechanical Science and Technology》2002,16(7):975-985
This paper deals with theoretical model developed for analyzing the heat transfer of automotive cooling systems. The model
has a modular structure which links various cooling system submodels. From the model, heat transfer rate of automotive cooling
systems can be predicted, providing useful information at the early stages of the design and development. The aim of the study
is to develop a simulation program for automotive cooling system analysis and a performance analysis program for analyzing
heat exchanger. Heat release rate from combustion gas to coolant through the cylinder wall in engine cylinder was analyzed
by using an engine cycle simulation program. In this paper, details of each submodel are described together with the overall
structure of the vehicle model. 相似文献
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Recently, the electrically controlled fuel injection type motorcycle has been emphasized in order to meet regulations for
exhaust emissions. However, there are many difficulties in selecting the control parameters because the pulsation phenomenon
occurs in the intake port due to the higher speed operating range and the smaller layout than for a passenger car. Therefore,
we investigated the injector spray characteristics which are applied to a 4-valve motorcycle gasoline engine. The spray characteristics
were visualized by using a CCD camera synchronized with the stroboscope at 6000 rpm. Furthermore, we compared the simulation
results using the VECTIS code with experimental results. The results showed that the trajectory of the spray was directed
towards the lower wall of the intake port when the fuel was injected at closed valve timing. On the other hand, when the fuel
was injected at open valve timing, a large portion of the fuel was lifted towards the upper half of the port. In addition,
open valve injection makes fuel evaporation time short; this resulted in better mixture formation than a closed valve injection.
From this result, we found that injection timing has a great effect on the mixture formation within a motorcycle cylinder. 相似文献
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往复惯性力会给发动机造成震动,笔者通过曲轴连杆的力学分析和数学模型计算,在曲柄壁上加过量的平衡重,来转移往复惯性力,减小振动,提高摩托车的舒适性能. 相似文献
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针对实际高原场景下,部分柴油机出现了缸盖局部烧蚀的问题,对不同海拔条件下柴油机缸内传热过程及其对发动机缸盖热状态的影响进行了研究,通过仿真手段计算得到了不同海拔条件下缸盖火力面的温度场分布情况。结合高原实机试验的具体数据,在确定缸盖热侧的边界条件时考虑了两种情况,分别是仅考虑对流换热以及同时考虑了对流和辐射换热的情况。通过对比两种边界条件下的仿真结果,分析研究了缸盖温度场随海拔高度的变化规律及其成因。研究结果表明,缸内对流传热量随海拔的上升逐渐下降,4 500 m海拔缸盖最高温度点温度较平原下降6.2%;缸内辐射和对流的传热总量随海拔高度的上升而上升,4 500 m海拔缸盖最高温度点温度较平原上升15.6%,说明了缸内辐射对换热产生的影响。 相似文献
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利用商用软件STAR—CD及ES—ICE对某D6114柴油机在的缸内燃烧过程进行了数值模拟计算,分析和比较了不同喷油提前角对缸内燃烧过程和燃烧室表面热流的影响。研究结果表明:喷油提前角提前,柴油机缸内的燃烧效果优于喷油提前角推迟,燃烧过程中缸内的压力和温度比推迟喷油提前角时要大,同时缸内的最高燃烧压力和最高温度也高;喷油提前角对缸盖和活塞顶壁面平均热流的影响与其对缸内平均温度的影响相似,对缸套壁面的影响是喷油提前角提前越早,传给缸套的热流越小。数值计算结果为高功率、高强化和低热损的柴油机设计提供理论依据。. 相似文献
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随着柴油机性能的不断强化,气缸盖的传热与热负荷成为一个非常重要的研究方向。首先利用Pro/E软件建立了柴油机气缸盖的几何模型,并对其进行了必要的简化处理;然后利用Hypermesh8.0对气缸盖进行网格划分,利用流固耦合的方法得到三维热边界条件;最后通过ABAQUS软件对柴油机整个冷却系统进行一维冷却计算分析,得出气缸盖火力面的温度场云图。 相似文献
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A numerical method is presented for calculating the temperature fields in a semi-adiabatic diesel engine piston having a cooling oil canal. The crown face of the piston is coated by a 2 mm thick oxide based ceramic insulating material. The non-ideal thermal contacts between the piston circumference and cylinder wall are also considered. A detailed analysis has been given for estimating the boundary conditions of the cylinder-piston assembly of an internal combustion engine. The isothermic distribution in the piston body and the heat flow rate through the different cooling media at four different engine loads have been depicted both for the cases with and without insulation coating. The results indicate a reduction (12–30%) in heat loss through the piston by use of an insulation coating at the piston crown face, assuming that both the heat transfer process from and the temperature of the combustion products remain unchanged. 相似文献