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

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 clearance check chart to validate.
• At 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:

• CLEARANCE 'L' CHECK

1. Create the fender surface for wheel arch study.

2. Create sketch as per european standards.

3. Project the sketch on the fender surface to get SA, SB, SC, SD, SE sections.

4. Plot points on fender surface SA, SB, SC, SD, SE lines .

5. Calculate clearance 'L' -distance from plotted points to wheel's outer most surface.

• CLEARANCE 'a' CHECK

1. Draw clearance 'a' line between fender and wheel at SB 30 degrees forward and SC 50 degrees rearward.

2. Measure this clearance 'a' and prepare clearance check chart.

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.