Description : The two reference fuel used for cetane rating are (a) Cetane and iso octane (b) Cetane and tetra ethyl lead (c) Cetance and n-heptane (d) Cetane and α- methyl naphthalene
Last Answer : Ans : d
Description : A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of a) 75% iso-octane and 25% normal heptane b) 75% normal heptane and 25% iso-octane c) 75% petrol and 25% diesel d) 75% diesel and 25% petrol
Last Answer : Answer: a Explanation: None.
Description : Octane number of gasoline is obtained by comparing the performance of the engine when running on a mixture of the following hydrocarbons A. ethane and methane B. normal heptane and iso-octane C. iso-heptane and octane D. iso-octane and TEL
Last Answer : ANSWER : B
Description : Which of the following fuel detonates readily? a) Benzene b) Iso-octane c) Normal heptane d) Alcohol
Last Answer : Answer: c Explanation: Normal heptane detonates readily.
Description : Which of the following fuel has little tendency towards detonation? a) Benzene b) Iso-octane c) Normal heptane d) Alcohol
Last Answer : Answer: b Explanation: Benzene has little tendency towards detonation.
Description : A mixture containing 65% of iso-octane and 35% of normal heptane will have a) cetane number 65 b) octane number 65 c) cetane number 35 d) octane number 35
Last Answer : Answer: b Explanation: A mixture containing 65% of iso-octane and 35% of normal heptane will have octane number 65 as octane number is the number percentage containing iso-octane.
Description : The normal heptane(C7H16) is given a rating of ____________ octane number. a) 0 b) 50 c) 100 d) 120
Description : Iso-octane is used as a reference substance in the definition of octane number and it is assigned an octane number value of 100. Iso-octane is chemically known as (A) α-methyl naphthalene (B) 2-2-4 tri methyl pentane (C) 1, 3 butadiene (D) Tetra methyl ethylene
Last Answer : (B) 2-2-4 tri methyl pentane
Description : The compound that has the least value for octane number is – (1) 2-methyl heptane (2) Iso-octane (3) 2,2-dimethyl hexane (4) n-heptane
Last Answer : (4) n-heptane Explanation: Octane rating or octane number is a standard measure of the performance of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand. Isooctane (upper) has an octane rating of 100 whereas n-heptane has an octane rating of O.
Description : The compound that has the least value for octane number is : (1) 2-methyl heptane (2) Iso-octane (3) 2,2-dimethyl hexane (4) n-heptane
Last Answer : n-heptane
Description : A fuel of cetane number 40 has the same ignition quality as a mixture of a) 40% cetane and 60% alpha methyl naphthalene b) 40% alpha methyl naphthalene and 60% cetane c) 40% petrol and 60% diesel d) 40% diesel and 60% petrol
Last Answer : Answer: a Explanation: A fuel of cetane number 40 has the same ignition quality as a mixture of 40% cetane and 60% alpha methyl naphthalene as cetane number is counted on cetane percentage.
Description : In any fuel, the percentage by volume of isooctane in a mixture of isooctane and n-heptane which will knock under same conditions as the fuel being tested, is called : (a) Cracking (b) Iodine number (c) Aromatization (d) Octane number
Last Answer : Octane number
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 : In a SI engine, which one of the following is the correct order of the fuels with increasing detonation tendency? (a) Paraffins, olefins, naphthenes, aromatics (b) Aromatics, naphthenes, paraffins, olefins (c) Naphthenes, olefins, aromatics, paraffins (d) Aromatics, naphthenes, olefins, paraffins
Last Answer : Ans :d
Description : Which are the reference fuels for knock rating of S.I. engines ?
Last Answer : n-heptane and ISO-octane.
Description : By higher octane number of SI fuel, it is meant that the fuel has (a) Higher heating value (b) Higher flash point (c) Lower volatility (d) Longer ignition delay
Description : The knock in diesel engine occurs due to A. instantaneous and rapid burning of the first part of the charge B. instantaneous auto ignition of the last part of the charge C. delayed burning of the last part of the charge D. reduction of delay period
Last Answer : ANSWER : A
Description : The _____________ sensor, senses rotation of engine camshaft for speed and timing of injection. a) throttle position b) manifold pressure c) camshaft position d) knock
Last Answer : Answer: c Explanation: The camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection whereas the throttle position sensor, senses the movement of the throttle ... engine intake manifold so that the mixture strength can be adjusted with changes in engine load.
Description : The ___________ sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load. a) throttle position b) manifold pressure c) camshaft position d) knock
Last Answer : Answer: b Explanation: The manifold pressure sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load and the camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection.
Description : The _____________ sensor, senses the movement of the throttle plate so that the mixture flow can be adjusted for engine speed and acceleration. a) throttle position b) manifold pressure c) camshaft position d) knock
Last Answer : Answer: a Explanation: The throttle position sensor, senses the movement of the throttle plate so that the mixture flow can be adjusted for engine speed and acceleration while the manifold ... the camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection.
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 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 : Octane number of n-heptane is assumed to be (A) 100 (B) 0 (C) 70 (D) ∞
Last Answer : (B) 0
Description : Which of the following binary systems is an example of a maximum boiling azeotrope? (A) Water-hydrochloric acid (B) Acetone-carbon disulphide (C) Water-ethyl alcohol (D) n-heptane-n-octane
Last Answer : (A) Water-hydrochloric acid
Description : A fuel with octane number 90 means it is as good as a mixture of : (a) 90% Isooctane + 10% n-heptane (b) 90% n-Heptane + 10% isooctane (c) 2 Litre of 90% isooctane + 2 litre of benzene (d) 2 Litre of 90% n-heptane + 2 litre of benzene
Last Answer : 90% Isooctane + 10% n-heptane
Description : Which of the following compounds is assigned the Octane Number of 100 : (a) n-Heptane (b) 2,3,3-Trimethylpentane (c) n-Octane (d) 2,2,4-Trimethylpentane
Last Answer : 2,2,4-Trimethylpentane
Description : Which of the following compounds is assigned the Octane Number of zero : (a) n-Octane (b) 2,3,3-Trimethylpentane (c) n-Heptane (d) 2,2,4-Trimethylpentane
Last Answer : n-Heptane
Description : The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and n octane into pure compounds each at 1 atm is (A) -2 RT ln 0.5 (B) -RT ln 0.5 (C) 0.5 RT (D) 2 RT
Last Answer : (B) -RT ln 0.5
Description : The economical diesel fuels have got octane rating varying from a) 30 to 50 b) 30 to 60 c) 20 to 30 d) 25 to 30
Last Answer : b) 30 to 60
Description : Cetane number of alpha methyl naphthalene is assumed to be (A) 0 (B) 100 (C) 50 (D) ∞
Last Answer : (A) 0
Description : Ignition timing of a multi-cylinder SI engine can be adjusted by A. rotating the cam shaft B. adjusting the generator pulley C. rotating the distributor D. adjusting the pump pulley
Last Answer : ANSWER : C
Description : Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine
Last Answer : ANSWER : D
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 : In a variable speed SI engine, the maximum torque occurs at the maximum (a) Speed (b) Brake power (c) Indicated power (d) Volumetric efficiency
Description : Velocity of flame propagation in SI engine is maximum for a fuel air mixture which is (a) 10% richer than stoichiometric (b) Equal to stoichiometric (c) More than 10% richer than stoichiometric (d) 10% leaner than stoichiometric
Description : A two stroke engine has a speed of 750 rpm. A four stroke engine having an identical cylinder size runs at 1500 rpm. The theoretical output of the two stroke engine will (a) Be twice that of the four stroke ... ) Be the same as that of the four stoke (d) Depend upon whether it is a CI or SI engine
Last Answer : Ans :c
Description : The method of determination of indicated power of multi cylinder SI engine is by use of (a) Morse test (b) Prony brake test (c) Motoring test (d) Heat balance test
Last Answer : Ans : a
Description : For the same capacity engines, the compression ratio of diesel engine a. is lower than the compression ratio of SI engine b. is higher than the compression ratio of SI engine c. is same as the compression ratio of SI engine d. cannot say
Last Answer : ANSWER b. is higher than the compression ratio of SI engine
Description : How the efficiency of the SI engine is affected by the specific heat ratio (γ) of the working fluid? a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working ... not affected by change in specific heat ratio (γ) of the working fluid d. none of the above
Last Answer : ANSWER a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working fluid
Description : Why iso-octane is chosen as reference fuel for S.I. engines and allotted 100 value for its octane number ?
Last Answer : Iso-octane permits highest compression without causing knocking.
Last Answer : Iso-octane permits highest compression without causing knocking
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 : Which of the following statement is not correct with respect to alcohols as alternate fuel in IC engines a) anti-knock characteristics of alcohol is poor b) alcohol contains about half the heat ... /litre c) alcohol does not vaporize as easily as gasoline d) alcohols are corrosive in nature
Last Answer : Answer: a Explanation: Anti-knock characteristics of alcohol is good.
Description : The _____________ sensor,is a microphone type sensor that detects ping or pre-ignition noise so that the ignition timing can be retarded. a) throttle position b) manifold pressure c) camshaft position d) knock
Last Answer : Answer: d Explanation: The knock sensor,is a microphone type sensor that detects ping or pre-ignition noise so that the ignition timing can be retarded while the camshaft position sensor, senses ... the engine intake manifold so that the mixture strength can be adjusted with changes in engine load.
Description : Anti-knock for compression ignition engines is a) napthene b) tetra ethyl lead c) amyl nitrate d) hexadecane
Last Answer : Answer: c Explanation: Amyl nitrate is the anti-knock for compression ignition engines.
Description : Gasoline with an octane number of 90 is equivalent in knocking characteristics to a mixture of heptane and isooctane of the following composition : (a) 20% heptane + 80% isooctane (b) 90% heptane + 10% isooctane (c) 80% heptane + 20% isooctane (d) 10% heptane + 90% isooctane
Last Answer : 10% heptane + 90% isooctane
Description : Octane of natural gas is a) 60-80 b) 80-100 c) >100 d)
Last Answer : Answer: c Explanation: The octane number of natural gas is always >
Description : Octane number of petrol normally used in petrol engines is of the order of a. 20-30 b. 40-60 c. 60-70 d. 80-90
Last Answer : ANSWER d. 80-90
Description : Ignition quality of diesel is expressed by a. octane number b. cetane number c. calorific value d. carbon content
Last Answer : ANSWER b. cetane number