英文版-第二章-汽车燃油经济性课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Chapter Two-Fuel Economy of Vehicle,What is aim of fuel economy?,To finish the unit transportation load with minimum fuel consumption.,2.1 Evaluation Index,（评价指标）,:,1.Fuel consumption quantity per unit distance,Q,（）,单位行程燃油消耗量,2.Fuel consumption quantity per unit distance and unit work load-,（）,单位运输工作燃油消耗量,Note:In USA MPG,（,miles per gallon,）,1 mile1.8 km;1gallon=3.758l(liter),American cars 2030 MPG 8.310.4l/100km,Japanese cars 2840 MPG 5.27.5l/100km(,Prius,:33km/l),2.2 Calculation of Fuel Consumption of Vehicle,1.The Equation of Fuel Consumption,Chapter Two-Fuel Economy of Ve,1,Clue:,unit:,Pe(kw);T,tq,(Nm);ge(g/kwh),G,T,(kg/h);(N/l);Q(l/100km);,Note:Q,is always concerned with g,e,;,:,for gasoline =7.2(N/l),for diesel =8.2(N/l),Clue:,2,2.Fuel Consumption Performance of Engine,2.1,Fuel consumption performance-needed output power characteristics of engine,（负荷特性）,To,describe how the performance of engine develops with the change of load of the vehicle that is the needed output power of engine,Definition:,output-power ratio,(,负荷率）,=,(,needed output power of engine,)/(,maximum power,available of the engine,),=u2/u0,Note:,For,Q,(,）,Pe,is the corresponding Y-coordinate value of,(P,f,+P,w,)/,T,curve in the Graph of Power Equilibrium;,g,e,could be available from the,right graph with given,n;,Conclusion:,（,under given n),Pe,increases with the decrease of,g,e,under the given,n,(in most instance);,output-power ratio,always increases with the decrease of,g,e,(in most instance);,g,e,meets its minimum value when the,output-power ratio,come close to 80%,;,2.Fuel Consumption Performanc,3,2.2 Universal Characteristics of Engine,（万有特性）,3.Power Equilibrium,When,level road&constant speed,Note:,Pe,is the power needed by the vehicle to maintain the constant speed drive on the level road;For calculating the fuel consumption,Pe,that exist in the formula of Q(Q=ge.,Pe,/1.02u,a,)must result from the calculation of,P,e,that is the needed power to maintain the constant speed drive on the level road,2.2 Universal Characteristics,4,Q-Ua,Fuel consumption performance-needed,output power,characteristics of engine,（负荷特性图）,Vehicle Power Equilibrium Graph,（功率平衡图）,4.Fule consumption calculation of vehicle with constant speed drive on level road(Stable Mode),（稳定行驶）,(Q-U,a,),4.1 Method One:,Step,:,Q-UaFuel consumption performan,5,Q-Ua,Universal Characteristic Graph of Engine,Power Equilibrium Graph,4.2 Method Two,：,Step:,Q-UaUniversal Characteristic G,6,5.Fuel consumption caculation of the vehicle under the drive cycle,（循环行驶工况的油耗计算）,Basic drive cycle,comprises of four parts:,acceleration,constant speed,deceleration,parking,5.1 The total fuel consumption of deceleration:,based on the fuel consumption of idle condition,Two ways for deceleration:,correspondingly,Losing the pedal and slipping the gears into neutral,（空档、怠速）,Losing the pedal and keeping the gears at their drive places,（挂档、怠速）,Two sorts of idle,（怠速）,fuel consumption:,Idle fuel consumption,（怠速油耗）,Forced idle fuel consumption,（强制怠速油耗）,0.28 ml/s,Usually the,idle fuel consumption,caused by the first way is quite similar with the forced idle fuel,consumption caused by the second way.,So,5.Fuel consumption caculation,7,5.2 The total fuel consumption of constant speed,:,known quantity:,So,5.3 The total fuel consumption of acceleration,:,5.2 The total fuel consumption,8,So,2.3 Influence Factors of Fuel Economy,Vehicle usage aspect,1.1 U,a,（,given i,g,）,To analyze the reason of why Q changes according to the trend of high-low-high,with the change of U,a,high-low-high,9,Conclusion:,The increase of,g,e,caused by much lower output-power ratio is the main factor causing the increase of,Q,when the vehicle is driven with low speed;,Although,g,e,decreases greatly for the increase of output-power ratio,the tremendous increase of needed power-,p,e,is the main factor causing the increase of,Q,when vehicle is driven with high speed;,Because of the above two conclusions,Q,could possibly meet its lowest value when the vehicle is driven with,the medium range of speed,where,g,e,and,p,e,would escape from getting their high value,and we call this range as Economy-Range of Speed,（经济车速区间）。,英文版-第二章-汽车燃油经济性课件,10,1.2 Gear Choice,（,given U,a,）,To analyze the reason of why Q is different with the change of gear under a given U,a,Conclusion:,Q increases with choosing lower gear;,Q decreases with choosing higher gear.,It is an evidence to prove that traditional vehicles,could not win in both acceleration performance and,economy performance.,1.2 Gear Choice（given Ua）To,11,1.3 Maintenance,Here maintenance mainly refer to the lubrication conditions of all the moving parts of the driveline.,We usually use coasting performance,（滑行性能）,of the vehicle to judge its lubrication conditions and we called this as Coasting Test(,滑行实验检查）,.,Usually the coasting distance is more than 230 meters with the initial vehicle speed of 50km/h or 30km/h,otherwise the vehicle is considered as the one with