ME465 Power Plant Midterm Exam Elements PDF

ME465 – Power Plant C) 15 : 1 MIDTERM TERMS D) 20 : 1 and less A branched system of pipes to carry waste ANSWER: D emissions away from the piston chambers of an internal combustion engine is called: Air standard efficiency of a diesel e...

ME465 – Power Plant C) 15 : 1 MIDTERM TERMS D) 20 : 1 and less A branched system of pipes to carry waste ANSWER: D emissions away from the piston chambers of an internal combustion engine is called: Air standard efficiency of a diesel engine depends on A) exhaust nozzle A) speed B) exhaust deflection pipe B) compression ratio C) exhaust pipes C) fuel D) exhaust manifold D) torque ANSWER: D ANSWER: B A diesel engine has An engine indicator is used to determine the A) 1 valve following B) 2 valves A) speed C) 3 valves B) temperature D) 4 valves C) volume of cylinder ANSWER: D D) mep and IHP A graph showing the power consumed ANSWER: D versus the time. As a result of detonation in an IC engine, A) chronological load curve following parameter attains very high value B) peak load A) peak pressure C) load duration curve B) rate of rise of pressure D) load curve C) rate of rise of temperature ANSWER: D D) peak temperature A heat engine utilizes the ANSWER: B A) calorific value of oil A stoichiometric air-fuel ratio is B) low heat value of A) chemically correct mixture C) high heat value of oil B) lean mixture D) mean heat value of oil C) rich mixture for idling ANSWER: C D) rich mixture for over loads Air fuel ratio at which a petrol engine cannot ANSWER: A work is Brake mean effective pressure is higher A) 8 : 1 than theoretical mean effective pressure on account of: B) 10 : 1 A) engine high speed B) 2:4:6 B) poor cooling system C) 2:3:5 C) high compression ratio D) 1:2:4 D) engine friction losses ANSWER: D ANSWER: D Ignition of the air fuel mixture in the intake of the exhaust manifold: Compression loss in IC engines occurs due to A) backlash A) leaking piston rings B) backfire B) use of thick head gasket C) exhaust pressure C) clogged air-inlet slots D) back pressure D) all of the above ANSWER: B ANSWER: D In a diesel engine fuel is injected: Diesel cycle consists of: A) At the beginning of compression stroke A) Isentropic, isothermal, constant volume, B) Before the end of compression stroke constant pressure process C) At the end of compression stroke B) Two constant volume, one constant pressure, one isothermal process D) After the end of compression stroke C) Two isentropic, one constant volume, ANSWER: B one constant pressure process In a typical medium speed 4-stroke cycle D) Two constant pressure, one constant diesel engine volume, one isentropic process A) compression starts at 35° after bottom ANSWER: C dead center and ends at top dead center For the same compression ratio B) compression starts at bottom dead center and ends at top dead center A) Otto cycle is more efficient than the Diesel C) compression starts at 10° before bottom dead center and, ends just before top dead B) Diesel cycle is more efficient than Otto center C) both Otto and Diesel cycles are, equally D) may start and end anywhere efficient ANSWER: A D) compression ratio has nothing to do with efficiency In loop scavenging, the top of the piston is ANSWER: A A) flat Foundation are preferably built of concrete B) contoured In the proportions of what measures of C) slanted Portland cement:sand:crushed stone? D) depressed A) 1:2:3 ANSWER: B In the opposed piston diesel engine, the D) Low injection pressure combustion chamber is located ANSWER: D A) above the piston Peak load for a period of time divided by B) below the piston installed capacity: C) between the pistons A) demand factor D) any when B) utilization factor ANSWER: C C) load factor Is the load of an installation or system at the D) capacity factor receiving terminal average over a specified interval of time ANSWER: B A) demand Prony brake is used for testing of: B) peak load A) small engines C) output B) large engines D) load curve C) engines having small flywheel ANSWER: A D) high speed engines Is the ratio between maximum demand and ANSWER: A connected load. Reserve capacity of a plant is given by: A) demand factor A) maximum demand - average load B) capacity factor B) plant capacity - maximum demand C) use factor C) plant capacity - average load D) diversity factor D) plant capacity x (1 - load factor) ANSWER: A ANSWER: B Leaking of a fluid between a cylinder and its Scavenging is usually done to increase piston during operation. A) thermal efficiency A) scavenging B) speed B) back pressure C) power output C) blow by D) fuel consumption D) turbo charging ANSWER: C ANSWER: C The air-fuel ratio of the petrol engine is Loss of power is due to: controlled by A) Poor compression A) fuel pump B) Restricted exhaust B) governor C) Clogging of air cleaner C) injector D) carburettor A) increase linearly ANSWER: D B) decrease linearly The calorific value of gaseous fuels is C) increase parabolically expressed in terms of D) decrease parabolically A) kcal ANSWER: B B) kcal/kg The ratio of the average load to the peak C) kcal/m2 load over a designated period of time is called: D) kcal/m3 A) load factor ANSWER: D B) reactive factor The fuel in diesel engine is normally injected at pressure of C) diversity factor A) 5 - 15 kg/cm2 D) plant use factor B) 20 - 25 kg/cm2 ANSWER: A C) 50 - 80 kg/cm2 The specific fuel consumption of a petrol engine compared to diesel engine of same D) 90 - 130 kg/cm2 H.P. is ANSWER: D A) same The maximum load consumed or produced B) more by a unit or grouped of units in a stated period of time. C) less A) connected load D) less or more depending on operating conditions B) peak load ANSWER: B C) load curve The term scavenging is generally D) load factor associated with ANSWER: B A) 2-stroke cycle engines The output of a diesel engine can be B) 4-stroke cycle engines increased without increasing the engine revolution or size in following way C) high efficiency engines A) feeding more fuel D) diesel engines B) supercharging ANSWER: C C) heating incoming air The working cycle in case of four stroke engine is completed in following number of D) scavenging revolutions of crankshaft ANSWER: B A) 1/2 The rating of a diesel engine, with increase B) 1 in air inlet temperature, will C) 2 Which of the following medium is compressed in a Diesel engine cylinder D) 4 A) air alone ANSWER: C B) air and fuel What does the area under the load curve give? C) air and lub oil A) energy consumed D) fuel alone B) maximum demand ANSWER: A C) base load D) average demand ANSWER: A What is the term as the ratio of the volume at the end of heat addition to the volume at the start of heat addition? A) compression ratio B) air-fuel ratio C) volumetric ratio D) cut-off ratio ANSWER: D Which does not belong to the group? A) air injection system B) mechanical injection system C) time injection system D) gas admission system ANSWER: C Which of the following is false statement. Excess quantities of sulphur in diesel fuel are objectionable because it may cause the following A) piston ring and cylinder wear B) formation of hard coating on piston skirts C) oil sludge in the engine crank case D) detonation ANSWER: D