Fender Design - Wheel Arch Challenge

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 another 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 purposes.

Fender

A 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 roads 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, pedestrians, and 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.

Fender Wheel Arch Regulations

Japan Regulations

• The clearance ‘L’ for tire, hub, cap and fender is to be measured within area K and create clearance check chart to validate
• The value of L should be greater than 5mm at all positions
• Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel

European Regulations

• The Clearance ‘L’ should be measured at sections SA-SA, SB-SB, SC-SC, SD-SD and SE-SE and create a clearance check chart to validate
• In all the five sections the value of L should be greater than 10mm to satisfy the European Regulations
• Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel

US Regulations

• Clearance ‘L’ is to be checked at all positions from -100° to 100° and create clearance check chart to validate
• The value of L should be greater than 5mm to satisfy the regulations
• Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel

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 outermost 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

Obtaining the clearance L at the designated 5 points

The clearance distance 'L' is calculated at points Section A, Section B, Section C, Section D and Section E, which should be greater than or equal to 10mm

Clearance 'L' at Section A

L = 10 mm

Clearance 'L' at Section B

L = 9.9490 mm

Clearance 'L' at Section C

L = 0.113949 mm

Clearance 'L' at Section D

L = -2.8860 mm

Clearance 'L' at Section E

L = -5.9973mm

Measuring the clearance value 'a' for Wheel Guard Requirement

Clearance 'a' at 30° line Section A

a = 44.7577mm

Clearance 'a' at 50° line Section C

a = 38.3599 mm

Conclusion

From the above results, we can conclude that the Fender does not pass the European Regulations, as the minimum clearance L between the Fender Wheel Arch and Wheel for vehicle and pedestrian safety is 10mm and this design does not meet the requirement.