# ICE exam 1

 .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Name the five processes in an internal combustion engine in order starting with compression CompressionCombustionExpansionExhaustIntake What is the range of power produced by internal combustion engines and what order of power is produced by the vast majority of engines? Range: 0.01 kW to 20x10^3 kWOrder: 10^2 kW What components of a reciprocating engine have remained basically the same since the later 1800s? reciprocating internal combustion engineengineblockpistonvalvescrankshaftconnecting rod Can both the spark ignition (SI) and compression ignition (CI) engines use the four stroke and the two stroke cycles? Yes What does knock limit in an Otto cycle engine? the maximum compression ratio of the Otto cycle engines What controls the power in a SI engine? the throttle What controls the power in a CI engine? the amount of fuel injected into the cylinder What limits the power of a CI engine? the formation of smoke (forms if there is inadequate mixing of the fuel and air) Does a diesel or C.I. engine have a throttle? No What is scavenging in a two stroke cycle? the pushing out of exhaust by the incoming air What is short circuiting in a two stroke engine? when some of the air goes straight through the cylinder and out the exhaust port Why is short circuiting particularly bad for carbureted engines? Instead of being in the crankcase, there is an air-fuel mixture. So, if short-circuiting occurs, fuel is wasted and there is increased hydrocarbon emissions. Which is greater, the brake power or the indicated power and why? Indicated power; due to friction bsfc is a valid measure of efficiency provided what parameter is held constant? q_c (the heat of combustion) Is the volumetric efficiency defined in Ferguson and Kirkpatrick chapter 1 dependent on the atmospheric or intake density? intake density What is a typical bmep and mean piston speed for an engine, independent of the size? bmep = 5 barmean piston speed = 5 m/s What causes the torque at maximum throttle to decrease as at high engine speeds. Viscous friction effects Which occurs at lower speed, maximum torque or maximum power? maximum torque Turbocharged intake pressure is greater than exhaust pressure units of Joule kg-m^2/s^2 units of Watt kg-m^2/s^3 n_R # revolutions/cycle2 stroke = 14 stroke = 2 N engine speed, rpm MEP mean effective pressure the average pressure acting on the expansion stroke that will produce the same amount of work as is produced by the cycle Work/displacement goes up when you turbocharge sfc specific fuel consumptionmdot_f/power or m_f per cycle/work per cycle can only compare engines that use the same fuel e_v volumetric efficiency n_c combustion efficiency99% + n_th fraction of heat converted to workWout/Qin n_f fuel conversion efficiency e_vi is less than or equal to 1.0 TRUE V_d displacement volumeunits: m^3/cycle Naturally aspirated anÂ internal combustion engine, in which fuel intake depends solely onÂ atmospheric pressure indicated identifies work being produced by the cylinder gases on the piston of the engine Brake the work measured from the output shaft R Rod/Crank ratiorod length/crank radium (1/2 stroke) When does r_c apply? Otto: 1-2 and 3-4Diesel: only 1-2r_c=V1/V2 .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Authorsivie13 ID236761 Card SetICE exam 1 Descriptionreview questions for exam Updated2013-09-24T17:25:47Z Show Answers