Fender Design - Wheel Arch Challenge

Aim: To calculate the Wheel Arch gap at required points and check whether the car passes the European standard.

Answer:

1. What is a Fender?

• Fender is a part of an automobile that frames a wheel well & prevents sand, mud, rocks, liquids, and other road particles from being thrown into the air by the rotating tire.
• Fenders 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 (centrifugal force) while the car is running.
• 

2. What is Wheel arch?

• Wheel Arch is the sem-circular part positioned above the wheel of the vehicle.
• The Wheel Arch area of the Fender is usually designed for the purpose of protecting the BIW from stones and other objects on the road as well as the Pedestrians.

3. Different regulations on Fender desgin?

a. Japan regulation

• The clearance ‘L’ between the tire and fender is to be measured & clearance is to be validated.
• 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.

b. European regulation

• 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

c. US regulation

• Clearance ‘L’ is to be checked at all positions from -100° to 100°.
• 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

4. To check if the given fender wheel arch design passes european regulation?

1. Given input data:

2. Sketch drawn to check clearance values:

• draw the sketch on a plane normal to tire & on its outer most surface.
• draw a horizontal line 0 degree & vertical line 90 deg, mark vertical line as SA
• from 90 deg line, draw a 30 deg line forward & 50 deg line rearward, mark as SB & SC as shown above.
• from 0 deg line, take a point on the fender & go up by 150mm to reach same line upwards, mark as SE.
• draw a bisector libe between SC & SE , mark it SD.

a. Clearance at SA = 9.95mm b. Clearance at SB = 10mm

c. Clearance at SC = 0.11mm d. Clearance at SD = 2.91mm

e. Clearance at SE = 5.99mm

3. To check 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

Clearance a @ SB = 43.6mm Clearance a @ SC = 38.6mm

To tabulate all the measured results:

Conclusion:

From the above clearance test, we see that only point SB satisfies 10mm gap & the remaining test points fail.

Wheel guard requirement of 5mm is satisfied on both points.

Hence , we conclude the given Fender design does not pass European regualtion standards.

We can give this data as an input to the styling team & improve the fender design on points which need more clearance.