第一章 发动机性能及其参数[1] 三种理想循环1)otto cycle : 2)diedel cycle : 3)dual cycle;(the efficiency lies between ~) isentropic compression ;addition of heat ;isentropic expansion ;rejection of heat;[2]评价理论循环的参数Cycle fuel conversion efficiency ηt 和Mean effective pressure Ptηt : The cycle fuel conversion efficiency ηt is used to evaluate the cycle economy ,which is defined as: (ηt increases with the increasing of compression ratio ε, pressure ratio λ,isentropic exponent K and decreases with the increasing of expan sion ratio ρ.) Pt : Pt is cycle work done by unit cylinder volume.It is used to evaluate the powercapability of a cylinder : (Pt increases with increasing of pa 、ε 、λ、ρ、 k and ηt .)[3]real cycle 实际循环1、intake(induct) stroke2、compression stroke3、power(combustion) stroke4、exhaust stroke[4] Which losses existed in real cycle compared with ideal cycle? explain every loss and the forming reason. (实际循环与理想循环相比，存在的损失及其形成原因。

)1) Heat transfer. Heat transfer from unburned mixture to the cylinder walls. Thepressure at the end of combustion in the real cycle will be lower. 2) Finite combustion time. Finite time required to burn the charge. The peak12121101Q Q Q Q Q Q W t -=-==ηSt V Wp =pressure in the engine is below the ideal cycle peak pressure value.3) Incomplete bustion of the cylinder charge is incomplete;theexhaust gases contain combustible species .4) Exhaust blowdown loss. The gas pressure at the end of expansion stroke isreduced.5) Crevice effects and leakage. These effects reduce the cylinder pressure .6)Pumping loss. The work is used to overcome the resistance in inlet and exhaustpassages.[5] engines indicated parameters a (发动机指示指标及作用？和类容)1>概念及作用：.Indicated parameters: The parameters are calculated on basis of the work done by working fluid to pistons .it is widely used to evaluate theconversion efficiency of heat into power per cycle and is widely used in engine research field .2>内容1、Indicated work per cycle Wi （循环指示功）2、Indicated mean effective pressure(imep) Pmi （平均指示压力）3、Indicated power Pi (指示功率)Pi(kw)=[Pmi(Mpa)*Vs(L)*n(r/min)*i]/[30*tao] （i 为汽缸数，tao 为冲程数）4、Indicated efficiency ηi （指示热效率）5、Indicated specific fuel consumption bi （指示油耗率） )()/()/(32m V m N W m N imep p s i mi ==ui i i i BH P Q W 3106.3⨯==η310)/())/((⨯=∙h kg B h kW g b i指示热效率与指示油耗率的关系 [6] engine brake parameters (何谓发动机有效指标及作用)1>概念：Engine brake parameters are based on engine crankshaft output work. It is used to evaluate economic and dynamic performance of an engine 。

2>内容：1.Brake torque Ttq and power Pe （有效转矩和有效功率）2. Brake work We and brake mean effective pressure Pme (有效功和平均压力)W e =W i -W m Wi---指示功 ； Wm---机械损失功3.Brake(thermal) efficiency ηe （有效热效率）4.Brake specific fuel consumption (bsfc) be （有效油耗率） 热效率有油耗率的关系5.Engine specific power PL （升功率）iu i b H 6106.3⨯=η)()/()/(32m V m N W m N bmep p s e me ==ue e e BH P Q W 31106.3⨯==η310)()/())/((⨯==⋅kW P h kg B bsfc h kw g b e e eu e b H 6106.3⨯=ηSe L iV P P =[7]engine mechanical efficiency (机械效率)定义：The ratio of the brake (or useful) power delivered by the engine to the indicated power is called the mechanical efficiency ηm : im i e m P P P P -==1η. 影响因素：The facts that influence it are: the peak combustion pressures in cylinder, engine speed or piston mean speed, engine loads, the characteristic of lubrication and temperature of cooling water, and the conditions of engine runs.第二章 发动机的换气[1] gas exchange processes of four-stroke engine. （四冲程发动机换气过程） The gas exchange process of an engine consists of the duration from opening the exhaust valve to closing the inlet valve .it can ba divided into four phases1.blowdown 自由排气2.displacement 强制排气3.induction process 进气行程4.valve overlap and scavenging 气门重叠与扫气[2] volume coefficient ηv 充量系数（容积效率） 重点定义：Volume efficiency is a measure of the effectiveness of the induction and exhaust process which is defined as the mass of fresh mixture which passes into the cylinder in one suction stroke, divided by the mass of this mixture which would fill the piston displacement at inlet density. γεεξη+-===1111a a s S S s a v T p p T V V m m . 提高充量系数In a qualitative analysis, volumetric efficiency Ƞv increases with:1) increasing mixture pressure at the end of intake stroke p a；（影响最大）2) suitable valve parameters ξandφ; 3) increasing compression ratio ɛ;4) decreasing mixture temperature at the end of intake stroke T a；5) reducing residual coefficient γ.必考内容（可能是大题）[3]effect of operating conditions and design on volumetric efficiency1.Inlet Match index 进气马赫数定义：The ratio of the typical velocity to the inlet sonic velocity, u /α, is called the inlet Mach index. When it exceeds 0.55, volumetric efficiency drops greatly.2.Effect of intake system friction 进气摩擦力3.Effect of inhaled charge heating 受热程度4.Effect of speed and valve timing 速度与气门正时5.Effect of intake runner length 进气管的长度第四章燃烧与化学[1] physical and chemical properties of petrol and diesel fuels?汽油及柴油的重要理化指标Characteristic of petrol or gasline . 汽油1)Antiknock performance 抗爆性定义：It is used to resists the tendency to produce detonation and this property .表示：The octane number(辛烷值) of a fuel is a measure of its anti-knock performance. 2)Volatility 挥发性标号 mark the number ：actane numberCharacteristic of diesel fuel . 柴油1）cetane number 十六烷值this indicates how readily the fuel self-ignites.（自燃性）2）volatility 挥发性 3）viscosity 粘度标号 mark the number ：solidifying temperature (凝点)[2] some alternative fuels.代用燃料。