Fender Design - Wheel Arch Challenge

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

Fender:

Fender is the part of an automobile, motorcycle or other vehicle body that frames a wheel well. Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire. In other words, the fender is a housing for the wheels that keeps road debris contained. If nothing cover the wheels, all kinds of debris would be kicked up by the rotating tires and hit the pedestrians and the vehicles comes behind on the road. Fenders are typically rigid and can be damaged by contact with the road surface.

Wheel Arch:

Wheel Arch is an arch shaped cavity in the fender body, which houses a wheel. The main intention for the calculation of wheel arc radius is to position the wheel inside the fender body , because during motion the car tyres will tend to throw particles present on the road like sand, mudrocks, liquids etc. into the air which may harm the pedestrians and cause problems.

Fender Wheel Arch Regulations:

Japan Standard Regulations:

• The clearance value ‘L’ for tire, hub, cap and fender in three different positions are checked within area K and the create the clearance check sheet to validate it.
• Clearance must be greater then 5 mm in all the three positions.
• Wheel guard requirement: The value of ‘a’ should be more than 5 mm at a all the three lines - 90^o perpendicular line and 30^o forward and 50^orearward from the central vertical axis of wheel.

US Standard Regulations:

• The clearance value ‘L’ should be measured at all positions from -20^o to 190^oat interval of 10^o and create the clearance check chart to validate it.
• The value of L should be greater than 5 mm at all the specified points to satisfy the US Regulations.
• Wheel guard requirement:The value of ‘a’ should be more than 10 mm at all the specified lines.

Europe Standard Regulations:

• The clearance value ‘L’ should be measured at sections SA-SA, SB-SB, SC-SC, SD-SD and SE-SE and create the clearance check chart to validate it.
• At all the five sections the value of L should be greater than 10 mm to satisfy the European Regulations
• Wheel guard requirement:The value of ‘a’ should be more than 10 mm at all the specified lines.

Calculation of wheel arch area according to European Regulations:

We must draw a sketch on the wheel's outermost surface in order to determine the clearance between the wheel arch and the wheel. The steps are listed below.

1. A Datum Plane is created at the outermost surface of the wheel.
2. The sketch is created on the new Datum Plane.
3. The bottom wheel arch is projected from the model to the sketch plane.
4. A Horizontal line is drawn across the centre of the wheel and the centre is mentioned as S.
5. A perpendicular line SA is drawn towards up from the centre of the wheel.
6. Two lines SB and SC are drawn at 30° forward of SA and 50° rearward of SA respectively.
7. A reference line is marked at 150 mm vertically above the base horizontal line (center of wheel).
8. A point is marked at the intersection of the wheel arch and the reference line.
9. A line SE is drawn from the wheel centre and passes from the point created.
10. Another line SD is drawn from the centre of the wheel such a way that it bisects the SC and SE line.
11. The points are marked at the intersection of wheel arch and the lines.
12. These 5 points is projected to the fender surface to measure the clearance between them.

Sketch:

Obtaining the clearance value:

The clearance value is measured in between the sketch points and the points projected on the fender.

1. SA -The clearance between the SA line and the wheel arch is 9.9490 mm and the wheel is positioned inside the fender.

2. SB -The clearance between the SB line and the wheel arch is 10 mm and the wheel is positioned inside the fender.

3. SC -The clearance between the SC line and the wheel arch is 0.113949 mm and the wheel comes out of the fender.

4. SD -The clearance between the SD line and the wheel arch is 2.8875 mm and the wheel comes out of the fender.

5. SE -The clearance between the SE line and the wheel arch is 5.9973 mm and the wheel comes out of the fender.

Overview of all sections:

Note: The negative sign is used to represent that the curvature of the fender wheel arch is inside the wheel outer surface.

Conclusion:

The Wheel Arch gap is calculated at required points and from the above results, we can conclude that the fender does not passes the European Standard Regulations as the minimum clearance between the fender wheel arch and the outer most surface of the wheel is not met at required points. Hence, the given fender model doesn't pass the European Standards and need to be modified.