Description : In a diesel engine the high temperature needed to ignite the fuel is achieved by – (1) using heat from exhaust (2) the battery (3) compressing air in the cylinders (4) an electrical spark
Last Answer : (3) compressing air in the cylinders Explanation: Diesel engines use the heat of compressed air to ignite the fuel (intakes air, compresses it, then injects fuel). Diesel engines need high compression ratios to generate the high temperatures required for fuel auto ignition.
Description : In a diesel engine the high temperature needed to ignite the fuel is achieved by (1) using heat from exhaust (2) the battery (3) compressing air in the cylinders (4) an electrical spark
Last Answer : compressing air in the cylinders
Description : In diesel engine the fuel injected would burn instantaneously at about compressed air temperature of A. 1000°C B. 250°C C. 450°C D. 2000°C
Last Answer : ANSWER : A
Description : The fuel in diesel engine is normally injected at pressure of a. 5-10 kg/cm2 b. 20-25 kg/cm2 c 60-80 kg/cm2 d. 90-130 kg/cm2
Last Answer : ANSWER d. 90-130 kg/cm2
Description : A diesel engine is usually more efficient than a spark ignition engine because a. Diesel being a heavier hydrocarbon, release more heat per kg than gasoline b. The air standard efficiency of diesel ... an Spark ignition engine d.Self ignition temperature of diesel is higher than that of gasoline.
Last Answer : ANSWER c. The compression ratio of a diesel engine is higher than that of an S.I engine
Description : In a 4 S diesel engine, the term ‘squish’ refers to the (a) Injection of fuel in the precombustion chamber (b) Discharge of gases from the precombustion chamber (c) Entry of air into the combustion chamber (d) Stripping of fuel from the core
Last Answer : Ans :c
Description : In a boiler enthalpy of water supplied was 2000 kJ/kg. Enthalpy being added by fuel combustion is 3200 kJ/kg. Using first law of thermodynamics, find amount of heat supplied if steam generation rate is 10 tons per hour.
Last Answer : Heat supplied Q = m (h2-h1) …….(Steady flow energy equation for boiler) ; h2=3200 KJ/kg h1=2000 KJ/kg m = 10 Tons /hour = (10 x 1000)/3600 kg/sec = 2.77 Kg/sec Q = 2.77(3200-2000) = 3324 KJ/sec heat supplied for 10 Tons/hr steam generation
Description : In a naturally aspirated diesel engine, the air is supplied by a A. supercharger B. centrifugal pump C. movement of engine piston D. reciprocating pump
Last Answer : ANSWER : C
Description : For spark ignition engine, the equivalence ratio of mixture entering the combustion chamber has values (A) for idling and for peak power conditions (B) for both idling and peak power conditions (C) for idling and for peak power conditions (D) for both idling and peak power conditions
Last Answer : ANSWER (B) for both idling and peak power conditions
Description : A spark plug is used in a. petrol engine b. diesel engine c. gas engine d. steam engine
Last Answer : ANSWER a. petrol engine
Description : Which of the following cycle is used for Spark Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle
Last Answer : Answer a. Otto cycle
Description : Scavenging air in diesel engine means a. air used for combustion under pressure b. forced air for cooling the cylinder c. burnt air containing products of combustion d. air used for forcing burnt gases out of the engines cylinder during the exhaust stroke
Last Answer : ANSWER d. air used for forcing burnt gases out of the engines cylinder during the exhaust stroke
Description : Which of the following is not related to spark ignition engine? a. fuel injector b. spark plug c. flywheel d. distributor
Last Answer : ANSWER a. fuel injector
Description : An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per ... kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ
Last Answer : ANSWER d. 973.5 kJ
Description : Which of the following is compressed in a diesel engine cylinder A. air B. fuel C. air and fuel D. air and lub oil
Description : The output of a diesel engine can be increased without increasing the engine speed or size in the following way A. feeding more fuel B. increasing the flywheel size C. heating intake air D. supercharging
Last Answer : ANSWER : D
Description : If the performance of diesel engine of different sizes, cylinder dimensions and power rating are to be compared, which of the following parameters can be used for such comparison? (a) Swept volume (b) Air fuel ratio (c) Specific brake fuel consumption (d) Volumetric efficiency
Description : Mixing of air and fuel in the diesel engine occurs in a. injection pump b. carburetor c. engine cylinder d. inlet manifold
Last Answer : ANSWER c. engine cylinder
Description : Which of the following medium is compressed in a diesel engine cylinder? a. air b. air and fuel c. air and lubricating oil d. fuel
Last Answer : ANSWER a. air
Description : Which of the following is not an internal combustion engine? a. petrol engine b. steam turbine c. diesel engine d. gas turbine
Last Answer : ANSWER b. steam turbine
Description : An engine is supplied with 4 kW of heat energy. It is found that it produce 4 kW of work. Which kind of perpetual machine it is? Which law is violated? Also describe other kind of perpetual machine you know.
Last Answer : PMM-II: A heat engine which violates Kelvin plank statement of the second law of thermodynamics is known as Perpetual Motion Machine of the second kind (PMM-II). Or 100 percent efficient machine which is ... no machine can produce energy of its own without consuming any other form of energy.
Description : Use of gasoline blend like tetraethyl lead in internal combustion engine a. increases the octane rating of the fuel b. allows engine to operate at higher compression ratio c. avoids auto-ignition of fuel d. all of the above
Last Answer : ANSWER d. all of the above
Description : The specific fuel consumption of a petrol engine compared to diesel engine of same H.P is A. same B.more C. less D. unpredictable
Last Answer : ANSWER : B
Description : If one cylinder of a diesel engine receives more fuel than others , then for that cylinder the A. exhaust will be smoky B. scavenging occurs C. exhaust temperature will be high D. engine starts overheating
Description : The specific fuel consumption for diesel engine is approximately A. 0.15 kg/kWh B. 0.2 kg/kWh C. 28 kg/kWh D. 0.36 kg/kWh
Description : The tendency of a diesel engine to knock increases if a. engine speed is increased b. engine power is increased c. cetane number of the fuel is increased d. compression ratio is increased
Last Answer : ANSWER d. compression ratio is increased
Description : The output of a diesel engine can be increased without increasing the engine size in following way a. injecting more fuel b. increasing flywheel size c. scavenging d. supercharging
Last Answer : ANSWER d. supercharging
Description : The specific fuel consumption per BHP hour for diesel engine is approximately a. 0.1 kg b. 0.2 kg c. 0.3 kg d. 0.4 kg
Last Answer : ANSWER b. 0.2 kg
Description : Fuel is injected into the cylinder at the end of ______________ stroke. a) suction b) compression c) expansion d) exhaust
Last Answer : Answer: b Explanation: Fuel is injected into the cylinder at the end of compression stroke and not at suction or expansion stroke.
Description : In reciprocating compressors, one should aim at compressing the air A. Adiabatically B. Isentropically C. Isothermally D. Polytropically
Description : In four stroke engine which of the following is also known as power stroke a. Suction stroke b. Compression stroke c. Expansion stroke d. Exhaust stroke (Ans:c) Measurements of fuel and air ... into IC engine,___________its efficiency A. increase B. decrease C. does not alter D. unpredictable on
Description : Why Joel's engine is unable to power his car the way it used to. The spark plug is working and the engine is compressing properly so what could be the problem?
Last Answer : Could be a fuel delivery problem such as a dirty fuelfilter.
Description : In a battery ignition system, the intensity of spark is A. minimum at low engine speed B. minimum at low engine speed and increases with engine speed C. maximum al low engine speed and decreases with engine speed D. maximum at low engine speed
Description : The compression ratio in a Spark Ignition (SI) engine is generally in between a. 7 to 10 b. 10 to 14 c. 14 to 18 d. 18 to 22 (Ans:a)
Last Answer : Which of the following is not true for two stroke engine as compared to four stroke engine? a. Less cooling is required b. Greater lubrication is required c. More uniform torque on crankshaft d. Complete exhaust of products of combustion (Ans:a)
Description : In a morse test for a 2 cylinder, 2 S SI engine, the brake power was 9 kW. Whereas the brake power of individual cylinders with spark cut off were 4.25 kW and 3.75 kW. The mecheffic of the engine is (a) 90% (b) 80% (c) 45.5% (d) 52.5%
Last Answer : Ans :a
Description : The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b d. None of these.
Last Answer : ANSWER c. Both a and b.
Description : Which of the following engine can work on very lean mixture a. Spark ignition engine b. compression ignition engine c. two stroke engine d. Four stroke engine
Last Answer : ANSWER b. compression ignition engine
Description : The tendency of a petrol engine to knock increases by a. supercharging b. scavenging c. increasing the engine horse power d. reducing the spark advance
Last Answer : ANSWER a. supercharging
Description : The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b. d. None of these.
Last Answer : ANSWER c. Both a and b
Description : The air requirement of a petrol engine during starting compared to the theoretical air requirement for complete combustion is A. more B.unpredictable C. same D. less
Description : The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is a. more b. less c. same d. may be more or less depending on engine capacity
Last Answer : ANSWER b. less
Description : If the temperature of intake air in internal combustion engine is lowered, the efficiency will a. increase b. decrease c. remains same d. increases upto certain limit and then decrease
Last Answer : ANSWER a. increase
Description : If the intake air temperature of Internal combustion engine increases, its efficiency will a. increase b. decrease c.remains same d unpredictable
Last Answer : ANSWER b. decrease
Description : For the best results of efficient combustion, high speed diesel engines need an approximate cetane number of a. 100 b. 50 c. 10 d. 5
Last Answer : ANSWER b. 50
Description : Keeping other parameters constant brake power of diesel engine can be increased by (a) Decreasing the density of intake air (b) Increasing the temperature of intake air (c) Increasing the pressure of intake air (d) Decreasing the pressure of intake air
Last Answer : Ans : c
Description : iesel engine has less reserve torque then spark ignition because ∙ Torque-speed curve is governed by volumetric efficiency of fuel pump and engine cylinder ∙ Torque is a function of thermal efficiency ∙ Diesel engine has generally low speed engine ∙ None of the above
Last Answer : ∙ Torque is a function of thermal efficiency
Description : In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature
Description : The efficiency of the Otto cycle is independent of a. Heat supplied b. Compression ratio c. Ratio of specific heats d. None of the above
Last Answer : Answer a. Heat supplied
Description : Air fuel ratio at which a petrol engine cannot work is A. 8:1 B. 12:1 C. 15:1 D. 20:1 and less
Description : Air fuel ratio for idling speed of a petrol engine is approximately A. 1:1 B. 5:1 C. 20:1 D. 10:1