SECTION-1

###### INTERNAL COMBUSTION ENGINE OBJECTIVE/ MULTIPLE CHOICE QUESTIONS

Q61. The brake power (B.P.) of the engine is given by

\begin{equation}
\text { (a) } B . P .=\frac{W l \times 2 \pi N}{60} \text { watts }
\end{equation}

\begin{equation}
\text { (b) } B . P .=\frac{(W-S) \pi D N}{60} \text { watts }
\end{equation}

\begin{equation}
\text { (c) B.P.= } \frac{(W-S) \pi(D+d) N}{60} \text { watts }
\end{equation}

(d) all of these

L= Length of arm in metres

N= Speed of engine in r.p.m.

S= Spring balance reading in newtons,

D = Dia. Of brake drum in metres and

d = Dia. Of rope in metres.

Ans: (d) all of these

Q62. The mechanical efficiency () of the engine is given by

\begin{equation}
\text { (a) } \eta_{m}=\frac{B . P .}{\text { I.P. }}
\end{equation}

\begin{equation}
\text { (b) } \eta_{m}=\frac{\text { I.P. }}{\text { B.P. }}
\end{equation}

\begin{equation}
\text { (c) } \eta_{m}=\frac{B . P X I . P .}{100}
\end{equation}

(d) none of these

\begin{equation}
\mathrm{Ans}:(\mathrm{a}) \eta_{m}=\frac{B . P .}{I . P .}
\end{equation}

Q63. The two reference fuels used for cetane rating are

(a) cetane and iso-octane

(b) cetane and alpha-methyl naphthalene

(c) cetane and normal heptane

(d) cetane and tetra ethyl lead

Ans: (b) cetane and alpha-methyl naphthalene

Q64. Which of the following fuel has little tendency towards detonation ?

(a) Benzene

(b) Iso-octane

(c) Normal heptane

(d) Alcohol

Ans: (b) Iso-octane

Q65. The delay period in compression ignition engines depends upon

(a) temperature and pressure in the cylinder at the time of injection

(b) nature of the fuel mixture strength

(c) relative velocity between the fuel injection and air turbulence pressure of residual gases

(d) all of the above

Ans: (d) all of the above

Q66. Which of the following statement IS wrong?

(a) In compression ignition engines, detonation occurs near the beginning of combustion.

(b) Since the fuel, in compression ignition engines, is injected at the end of compression stroke, therefore, there will be no pre-ignition.

(c) To eliminate knock in compression ignition engines, we want to achieve auto-ignition not early and desire a long delay period.

(d) In compression ignition engines, because of heterogeneous mixture, the rate of pressure rise is comparatively lower.

Ans: (c) To eliminate knock in compression ignition engines, we want to achieve auto-ignition not early and desire a long delay period.

Q67. The ignition of the charge by some hot surface within the engine before the passage of spark is called

(a) pre-ignition

(b) detonation

(c) ignition delay

(d) auto-ignition

Ans: (a) pre-ignition

Q68. A supercharged engine as compared to an ordinary engine

(a) is lighter

(b) requires smaller foundations

(c) consumes less lubricating oil

(d) all of these

Ans: (d) all of these

Q69. The purpose of testing an internal combustion engine is

(a) to determine the information, which can not be obtained by calculations

(b) to conform the data used in design, the validity of which may be doubtful

(c) to satisfy the customer regarding the performance of the engine

(d) all of the above

Ans: (d) all of the above

Q70. Number of working strokes per min. for a two stroke cycle engine are………..the speed of the engine in r.p.m.

(a) equal to

(b) one-half

(c) twice

(d) four-times

Ans: (a) equal to

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##### Read More Sections of Internal Combustion Engine

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Internal Combustion Engine MCQ – Section-1

Internal Combustion Engine MCQ – Section-2

Internal Combustion Engine MCQ – Section-3

Internal Combustion Engine MCQ – Section-4