Mechanical Engineering Quiz: IC Engine

Questions and Answers

In a 4-stroke IC engine, what is the ideal turning moment diagram during the compression stroke?

Positive throughout

Negative during the major portion of the stroke then goes positive

Negative throughout (correct)

Positive during the major portion of the stroke then goes negative

Which material is most commonly used for manufacturing worm gears?

Phosphor Bronze (correct)

Nylon 66

Cast iron

High Carbon Steel

The path of contact in cycloidal tooth profile gears is a straight line.

False

What is the circular pitch of the spur gear if it is stated to be 4 mm?

4 mm Signup and view all the answers

The number of teeth of the gear with a circular pitch of 4 mm and a pitch circle diameter of 28 mm is _____________

22 Signup and view all the answers

The mass moment of inertia of the flywheel (rim type) is______ kg/m² when the maximum fluctuation of energy is 400 Nm.

0.175 Signup and view all the answers

What is the first area between the output torque curve and resistance line in the turning moment diagram for the engine running at 180 rpm?

-340 mm2 Signup and view all the answers

Match the gear design characteristics with their definitions:

Pressure angle = Angle between the line of action and common normal Circular pitch = Distance from one point on one tooth to the corresponding point on the next tooth Pitch circle = Circle that serves as the basis for gear measurements Gear ratio = Ratio of the number of teeth on two meshing gears Signup and view all the answers

Which of the following statements is true regarding the equilibrium of a member under three forces?

All of the above. Signup and view all the answers

For a two-force member to be in equilibrium, the two forces must be equal and collinear.

True Signup and view all the answers

What is the point where the lines of action of three concurrent forces intersect called?

Point of concurrency Signup and view all the answers

A ________ is used to analyze forces acting on a mechanism.

free-body diagram Signup and view all the answers

What is the direction of the torque applied to link 'OA' in the slider-crank mechanism?

Clockwise Signup and view all the answers

In the four-bar mechanism with given link dimensions, what is the torque exerted on link AB if only T4 is considered?

20 Nm in counterclockwise direction Signup and view all the answers

Match the following terms with their definitions:

Equilibrium = State where the sum of forces is zero Torque = A measure of the rotational force Free-body diagram = Isolated representation of all forces and moments Slider-crank mechanism = A mechanical system converting linear motion to rotational motion Signup and view all the answers

In a slider-crank mechanism, the slider can move in straight lines.

True Signup and view all the answers

Study Notes

Link Dimensions and Static Equilibrium

Link dimensions: AB = 40 mm, BC = 60 mm, CD = 50 mm, AD = 30 mm, DE = 20 mm.
Input torque on link 'AB' is to be determined for static equilibrium.

4-Stroke IC Engine Turning Moment Diagram

Ideal turning moment diagram during compression stroke:
- Options:
  - A) Positive throughout
  - B) Negative throughout
  - C) Positive then negative
  - D) Negative then positive

Worm Gears Material

Common materials for manufacturing worm gears include:
- A) Cast iron
- B) High Carbon Steel
- C) Phosphor Bronze
- D) Nylon 66

Cycloidal Tooth Profile Gears Characteristics

Characteristics of cycloidal tooth profile gears:
- A) Constant pressure angle
- B) Straight line contact path
- C) Variation in center distance affects angular speed ratio
- D) Increased interference

Fill in the Blanks

For a spur gear with circular pitch = 4 mm and pitch circle diameter = 28 mm:
- Number of teeth = _____________.
Engine speed fluctuates between 210 rad/s and 190 rad/s; maximum energy fluctuation = 400 Nm.
- Mass moment of inertia of flywheel = ______ kg/m².

Turning Moment Diagram for Multi-Cylinder Engine

Diagrams indicate areas between output torque curve and resistance line:
- Areas: -340, +21, -245, +300, -118, +230, -225, +377 mm² at 180 rpm.
Flywheel mass = 1000 kg; maximum speed fluctuation limited to 3%.

Conditions for Equilibrium

A member experiences equilibrium under three forces if:
- Resultant of forces = zero.
- All forces are equal, parallel, and opposite.
- Lines of action intersect at a common point.

Two-Force Members Equilibrium

Two-force members must have forces that are:
- A) Equal and opposite.
- B) Parallel.
- C) Equal and collinear.
- D) Equal, opposite, and collinear.

Sketching of Mechanism Forces

A ________ represents a mechanism part with forces and couples to analyze force nature.

Torque Calculation

Torque T' on link 'OA' for the specified force system is _______ Nm in ______ direction.

Slider-Crank Mechanism Forces

Slider-crank dimensions: OA = 100 mm, AB = 450 mm.
Input torque T = 155 Nm applied clockwise; determine force 'F' magnitude and direction.

Four-Bar Mechanism Torque Analysis

For given dimensions:
- AD = 800 mm, AB = 300 mm, BC = 700 mm, CD = 400 mm.
- Link CD experiences T4 = 20 Nm (counterclockwise); calculate torque (T2) on link AB.

Force Applied at an Angle

Four-bar mechanism exerting force P = 100 N at 120°; further analysis required.

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Description

This quiz focuses on static equilibrium in mechanical systems, particularly involving link dimensions and torque calculations for a mechanism. It also includes questions about the turning moment diagram of a 4-stroke internal combustion engine during the compression stroke.