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 : 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 : 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 : 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 : 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 : Reference fuels for knock rating of SI engine fuels would include (a) Iso octane alpha methyl naphthalene (b) Normal octance and aniline (c) Isooctance and n octane (d) N heptane and iso octane
Description : The normal heptane(C7H16) is given a rating of ____________ octane number. a) 0 b) 50 c) 100 d) 120
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 : 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 : 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 : HUCR is the highest compression ratio at which the A. engine can be run B. engine gives maximum output C. engine is most efficient D. fuel can be used in a test engine without detonation
Last Answer : ANSWER : D
Description : The compression ratio cannot be increased beyond certain limit as it results in a. auto-ignition of fuel b. detonation c. engine knocking d. all the above
Last Answer : ANSWER d. all the above
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 : 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 : 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 : 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 : Disadvantage of hydrogen as a fuel in IC engine is a) storage is safe b) low NOx c) detonating tendency d) easy handling
Last Answer : Answer: c Explanation: None.
Description : The tendency of knocking in CI engine reduces by (a) High self ignition temperature of fuel (b) Decrease in jacket water temperature (c) Injection of fuel just before TDC (d) Decrease in injection pressure
Last Answer : Ans :c
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 : As a result of detonation in an I.C engine, following parameter attains a high value A. peak temperature B. peak pressure C. rate of pressure rise D. rate of temperature rise
Last Answer : ANSWER : C
Description : As a result of detonation in Internal combustion engines the following parameter attains very high value. a. peak pressure b. rate of rise of pressure c. rate of rise of temperature. d. peak temperature.
Last Answer : ANSWER b. rate of rise of pressure
Description : Detonation can be controlled by a. varying the compression ratio b. using lean mixture c. retarding the spark timing d. reducing the rpm
Last Answer : ANSWER c. retarding the spark timing
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 : Write the values of boiling temperature for cetane(diesel).iso-octane(petrol), Butane, Propane an methane fuel and write effect of it on its system.
Last Answer : Write the values of boiling temperature for cetane(diesel).iso-octane(petrol), Butane, Propane an methane fuel and write effect of it on its system.
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 : Octane number of n-heptane is assumed to be (A) 100 (B) 0 (C) 70 (D) ∞
Last Answer : (B) 0
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 : 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 : 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
Description : Ignition quality of petrol is expressed by a. Octane number b. cetane number c. calorific value d. self-ignition temperature
Last Answer : ANSWER a. Octane number
Description : In spark ignition engines, the knocking tendency can be decreased by a) decreasing compression ratio b) controlling intake throttle c) controlling ignition timing d) adding dopes like tetraethyl lead and ethylene dibromide
Last Answer : Answer: d Explanation: None.
Description : The knocking tendency in CI engines increases with (a) Increase of coolant water temperature (b) Increase of temperature of inlet air (c) Decrease of compression ratio (d) Increase of compression ratio
Description : Which of the following factors increases the tendency of knocking in the CI engines? (a) Increasing both the r and coolant temperatures (b) Increasing both the speed and the injection advance (c) Increasing the speed, injection advance and coolant temperature (d) Increasing the compression ratio
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 : Pick out the correct statement. (A) Paraffins have higher octane number than corresponding iso-paraffin (B) Paraffins have lower smoke point than aromatics
Last Answer : (B) Paraffins have lower smoke point than aromatics
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 : Pick out the wrong statement. (A) Alkylation produces a larger iso-paraffin (having higher octane number) from the reaction of an olefin with smaller iso-paraffin (B) Catalytic alkylation processes use HF ... (> 1000°C) (D) Gasoline having an octane number of 90 can be produced by alkylation process
Last Answer : (C) All the alkylation processes use very high temperature (> 1000°C)
Description : The colour of gasoline is an indication of its (A) Octane number (B) Lead susceptibility (C) Gum forming tendency & thoroughness of refining (D) None of these
Last Answer : (C) Gum forming tendency & thoroughness of refining
Description : Small amount of gasoline is added to alcohol to a) reduce the emission b) to increase the power output c) to increase the efficiency d) to improve cold weather starting
Description : Which of the following hydrocarbons of same carbon atoms has minimum smoking tendency? (A) Paraffins (B) Naphthenes (C) Aromatics (D) Iso-paraffins
Last Answer : (A) Paraffins
Description : Compare detonation and diesel knock on the basis of (i) Fuel Ignition Temperature (ii) Compression Ratio (iii) Speed (iv) inlet temperature (v) inlet pressure (vi) cylinder wall temperature (vii) cylinder size
Last Answer : Comparison between detonation and diesel knock: Parameter To avoid Detonation in SI Engine To avoid Diesel knock i) Fuel Ignition Temperature High Low ii) Compression Ratio ... Cylinder wall temperature Low High viii) Cylinder size Small Large
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
Description : The theoretically correct air fuel ratio of a petrol engine is of the order of A. 6:1 B. 10:1 C. 15:1 D. 20:1