Hood design-Week 2
OBJECTIVE:-
To Design a Car Hood Assembly by using the given outer panel skin and other data
1. INTRODUCTION;
The Hood is an important component of that covers the engine compartment and it decides the aesthetics of the car, is open to allow access to the engine compartment for maintenance and repair, and is the most important factor that decides the safety of the passenger and the victim
2. THE DESIGN ASPECT OF THE HOOD
I.The aesthetics covering the engine compartment from the outside
II.Access to the engine compartment for maintenance and repair
III.The safety of the passenger and the victim
IV.manufacturing ability
V.Head Clearance
VI.Cad data
VII.Nosie & vibration (NVH design)
I.The aesthetics
Hood decides the aesthetics of the car the hood covers the engine components and its skin is designed by the styling team and then its work is handed over to the next team to the body in the white engineering team there is some part in the hood, hood outer panel decide the aesthetics of the car
II.Access to the engine compartment for maintenance and repair
The hood access to the engine compartment is decided by the hinge axis of rotation and striker trajectory axis both things give a better path to the maintenance and repair and we have a part that provides better support it is called the support rod or gas stay
III.The safety of the passenger and the victim
The hood inner panel is part that decides the safety of the passenger and the victim
IV.manufacturing ability
I.deep drawing
The hood outer panel is made up of metal sheet it is processed by deep drawing methods and trimming methods
II.Draft analysis
V.HEAD CLEARANCE
The hood design contains an average human head zone in the region because there is a possibility of getting hit by the striker in the human head when he tries to access the engine component
The average heights of adult men and women were 1650 and 1520 mm
VI.CAD DATA
Hood inner panel thickness = 0.75mm
Hood outer panel thickness = 0.75mm
reinforcement thickness = 1.5mm
Hemming data
VII.NOISE & VIBRATION (NVH design)
The noise and vibration design means controlling the noise and vibration of the part using the introduction of a mastic point and stiffener
Overall views of the hood
3. Part of the hood
a.Outer panel
b.Inner panel
c.striker
d.striker reinforcement
e.hinge assembly
i)hinge engine side
ii)hinge hood side
f.hinge reinforcement
g.support rod or gas stay
i.support rod clamp & ball stud
j.mastic point or stiffener pad
a.Outer panel
The outer panel is a part of a car hood assembly that decided the aesthetics of the Car
The type of hood
i.inlaid hood
ii. wrap around hood
The wrap-around hood covers more area than the inland hood, and the area of the hood indirectly affects the safety of the car, the wrap-around distance and side reference line are things that affect the design of the hood
b.Inner panel
The inner panel decides the safety of the car, it is designed in the way that when the car met with an accident the force is observed within itself and gets colluded mostly, and the rest of the forces is transferred to the hinge, design also considers clearance between the engine compartment and the inner panel, minimum clearance is required between them,the position area of the hinge and striker must be a flat area
c.striker
The hood is locked with a two-release lever to open the hood ,the first release lever is inside near the driver and the second one is accessible from the outside of the hood
step-i-lever 1 open step-ii-leaver 2 open step-iii-lift the bonnet step-iv-position the support rod
The hood is open to access
It gives a better trajectory axis and it is dependent on the hinge axis of rotation.
d.striker reinforcement
It is used to give the striker additional strength like a liner to striker
e.hinge assembly
It is a sub-assembly that has two parts within itself
i)hinge engine side
ii)hinge hood side
f.hinge reinforcement
It is used to give the striker additional strength like a hinge
g.support road or gas stay
The decision of choosing a support rod or gas stay is Based on the weight of the hood if the weight of the hood can be lifted by the average human we will go with support rod or else we will go with the gas stay.
Support rod is used, given to support the hoods it is manually taken and placed in a manner to support the hood.
The height of the support road depends on the average human height in the region
Support rod must not be in a straight way and must be in a limited curved way
The support road must be positioned considering the components in the engine compartment. It might result in problem which is difficult for the maintenance so we must consider the layout.
The basic principle of a gas spring is the same as for a mechanical coil spring.Gas stay has some consideration and calculation for the design.
i.support road clamp & ball stud
The support road clamp is used to hold the support in its place.
Ball stud is used for the positioning of the gas stay in place and the access is given by the ball stud in proper axis.
k.mastic point or stiffener pad
Mastic point is a past used to provide the noise and vibration control.
Stiffener pad is a rubber pad used to provide noise and vibration control.
