Automobile Designer related Frequently Asked Questions by expert members with job experience as Automobile Designer. These questions and answers will help you strengthen your technical skills, prepare for the new job interview and quickly revise your concepts

## 65 Automobile Designer Questions and Answers:

### 1 :: Tell me what do you mean by Break Lines?

It is used to limit a broken section. For short break an uneven freehand thick line is recommended and for long breaks a long thin ruled dashes joined by freehand ‘ Zig Zags’ are used.

### 2 :: Do you know where is draft angle used?

Generally draft angle is used in moldings and drop forgings, parts of which maybe left un-machined.

### 3 :: What is Cycloid?

It is a curve which is generated by a point in the plane of a circle that rolls along a straight line.

### 4 :: Tell me which orthographic projection has been recommended by Bureau of Indian Standard(BIS)?

Third angle projection

### 5 :: Tell me in order to derive the torsional formulas what are the assumptions taken?

The torsion equation is derived on the basis of following assumptions:
☛ > The shaft material is uniform, throughout the shaft.
☛ > After the application of torques the plain section of a shaft remains plain.
☛ > Any twist that occurs in the shaft remains uniform and constant.
☛ > After the application of torque the distance between any two cross-sectional references remains constant.
☛ > The elastic limit value of a shaft is never exceeded even after the

### 6 :: Tell me what are the commonly used various methods of pictorial projection?

☛ (a) Isometric projection
☛ (b) Oblique projection
☛ (c) Perspective projection.

### 7 :: Explain me what is meant by development?

Development is the drawing of all the surfaces of an object on a plane to make a pattern. If it is folded or rolled it will form the required object. The main applications are in sheet metal work,sheet plastic fabrication and many other industrial applications.

### 8 :: Tell me what do you mean by detail drawing?

It shows the essential shape, size and specifications required for the construction of each unit of a product.

### 9 :: Tell me what is meant by interpenetration of solids?

If one solid penetrates into the other solid of the same or different cross section then surfaces of the both solids come in contact and outline of the penetrating solid can be seen which is called interpenetration of solid.

### 10 :: Explain me what is a sectional view?

The cross section of an object obtained by passing an imaginary cutting plane through the object is called sectional view.

### 11 :: Do you know what are the planes of projection?

Vertical plane(VP) and Horizontal plane (HP) are generally used in orthographic projection. These planes of an object are obtained to describe it clearly with all dimensions. These are known as principle planes and the position of an object can be fixed by following four quadrants:
☛ (1) First Quadrant: It is above HP and in front of VP.
☛ (2) Second Quadrant: It is above HP and behind VP.
☛ (3) Third Quadrant: It is below HP and behind VP.
☛ (4) Fourth Quadrant: It is below HP and in front of VP.

### 12 :: What is the principle of orthographic projection?

It is the method of representing the exact shape of an object in two or more views on planes. In this projection all the projectors are parallel to each other and perpendicular to the plane of projection. Projectors are assumed to come from infinity. It is generally used in machine drawing.

### 13 :: What is a Polygon?

It is plane closed figure having many sides and angles. A regular polygon has equal sides and equal angles.

### 14 :: Tell me what are the basis on which the best material for Sliding Contact Bearings manufacturing?

Some of the important properties to lookout for in the material for sliding contact bearings are as follows:
☛ > Compressive Strength: In order to prevent the permanent deformation and intrusion of the bearing the material selected should be possess a high compressive strength to bear the max bearing pressure.
☛ > Fatigue Strength: the material selected for the bearing should be able to withstand loads without any surface fatigue cracks getting created. This is only possible if the material has a high level of fatigue strength.
☛ > Comfortability: The material should be able to adjust or accommodate bearing inaccuracies and deflections without much wear and heating.
☛ > Embeddability: The material should allow the embedding of small particles without effecting the material of the journal.
☛ > Bondability: The bearings may be created by bringing together ( bonding ) multiple layers of the material. Due to the above reason the bondability of the material should be sufficiently high.
☛ > Thermal conductivity and corrosion resistance: Thermal conductivity is an essential property for bearing materials as it can help in quickly dissipating the generated heat. Also the material should have a level of corrosion resistance against the lubricant.

### 15 :: What is Hertzian stress? (a) Tensile stress on inner surface of cylinder (b) Bending stress on two contact surface (c) Contact stress on two contact surfaces (d) Shear stress on two contact surfaces

(c) Contact stress on two contact surfaces

### 16 :: Backlash is (a) Sum of the clearance of two gears (b) Mutual play between two gears (c) Amount by which the width of a tooth space exceeds the thickness of the engaging tooth on pitch circle (d) Any of the above

(c) Amount by which the width of a tooth space exceeds the thickness of the engaging tooth on pitch circle

### 17 :: A bolt of uniform strength can be developed by (a) Keeping the core dia of threads equal to the dia of unthreaded portion of bolt (b) Keeping the core dia of threads smaller than the dia of unthreaded portion of bolt (c) Keeping the nominal dia of threads equal to the dia of unthreaded portion of bolt (d) None of the above

(a) Keeping the core dia of threads equal to the dia of unthreaded portion of bolt

### 18 :: Short columns are preferred over long columns from (a) Strength consideration (b) Buckling consideration (c) Weight consideration (d) None of the above

(b) Buckling consideration

(d) Velocity

### 20 :: Explain me what are the different values that need to be determined in order to design a cylinder for an ICE?

The following values are needed to be determined:
☛ > Thickness of the cylinder wall: The cylinder walls in an engine is made witness to gas pressure and the side thrust of a piston. This results in two types of stresses: longitudinal and circumferential stress. Both the types of stresses are perpendicular to each other and hence it is aimed to reduce the resulting stress as much as possible.
☛ > Length and bore of the cylinder: The length of the cylinder and the length of the stroke is calculated on the basis of the formula: length of cylinder L = 1.15 times the length of the stroke (l). L = 1.15(l)
☛ > Cylinder flange and studs: The cylinders are always cast integral as a part of the upper crankcase or in some cases attached to it by means of nuts and bolts. The flange is integral to a cylinder and henceforth its thickness should be greater than that of the cylinder wall. The thickness of flange should generally be between 1.2t-1.4t where t is the cylinder thickness.
The stud diameter is calculated by equating gas load ( due to max pressure ) to the grand total of all the resisting forces of the studs.