Fender Design - Wheel Arch Challenge

Fender

Fender is a part of an automobile, motorcycle or other vehicle body that frames a wheel well (the fender underside). Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire. Fenders are typically rigid and can be damaged by contact with the road surface.

The main purpose of fenders on cars is that they shield the wheels and they protect the passengers, the pedestrians, and the other vehicles from stones, mud, liquid, and other debris that can fly in the air because of the speeding rotating wheels while the car is running.

Wheel Arch

• It is a curved part of the Fender positioned right above the Wheel.
• The Wheel Arch is designed such that it protects both the pedestrian and car cabin from mud, water rocks and other road spray
• Different countries have different wheel arch regulations in place, and the wheel arch design has to comply with them to be deemed usable in that country.
• For avoiding design alterations of the same vehicle to meet the different regulations in different countries, the maximum values of the concerned regulation parameters are taken into consideration for design purpose.

Fender Wheel Arch Regulations

European Regulations

Calculation of wheel arch area according to European Regulations

For calculation of clearance between Wheel Arch and Wheel we have to create a sketch on the outer most face of the wheel. The procedure of which is given below.

• A Datum Plane is created at the outermost face of the wheel. 
• The sketch is created on the new Datum Plane.
• A Horizontal line is drawn across the centre of the wheel.
• A perpendicular line SA is dropped at the centre of the wheel.
• Two lines SB and SC are created at 30° forward of SA and 50° rearward of SA respectively.
• A point is created 150mm vertically above the centre line.
• A line SE is drawn from the wheel centre and passes from the point created.
• Another line SD is drawn from the centre of the wheel and in the middle of lines SC and SE.

Applying European Standards to given Fender & Wheel Data:

Sketch

Obtaining the clearance L at the designated 5 points

The clearance distance 'L' is calculated at points SA-SA, SB-SB, SC-SC, SD-SD and SE-SE, which should be greater than or equal to 10mm

i.) Clearance 'L' at SA-SA

L = 10mm.

ii.) Clearance 'L' at SB-SB

L= 2.961 mm

iii.) Clearance 'L' at SC-SC

L = 3.143 mm

iv.) Clearance 'L' at SD-SD

L = 0.224 mm

Conclusion:

From the above results obtained, we can conclude that the given fender doesn't pass the European Standards for Wheel Arch area.

With this result, the styling team is required to modify the surface of the fender such that the clearance "L" at sections SB, SD and SC is equal to or greater than 10 mm by increasing the curvature at those sections towards the outside.