Fender Design - Wheel Arch Challenge

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

Fender is the American English term for the part of an automobile,motocycle 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 particles 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 is a curved part of the Fender positioned right above the wheel. The Wheel Arch is designed in such a way that it protects both the pedestrian and car cabin from mud, water rocks and other road spray. Different countries have different wheel arch regulations and the wheel arch design has to meet the regulations in order 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

Japanese Regulations

• The clearance ‘L’ for tire and fender is to be measured within area K.
• The value of L should be greater than 5mm at all positions.

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.

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

Procedure for calculation of wheel arch clearance according to European standards.

• First we create a datum plane on the outer surface of tyre.
• A sketch is created on the datum plane. Outer surface of the wheel and fender outer edge curves are projected on the datum plane.
• A centre point is created on the datum plane and two reference lines vertical and horizontal are drawn through the centre. vertical line is termed as line A.
• Now we create one more line at a distance of 150mm from horizontal line, this line is termed as line E.
• Two lines B and C are created at 30° forward of A and 50° reverse of A respectively.
• An intersection line is created between line C & E , this line is termed as line D.
• Now points are created on the intersection where these lines meet the fender outer curve.
• Now these points are projected on the fender and the clearence between them are termed as SA, SB, SC, SD, SD & SE.

Measuring clearance between the points created on the datum plane(Tyre outer surface) and points projected on the fender outer curve. Clearance value required is 10mm according to European standards.

Clearance at SA is 9.9490mm

Clearance at SB is 10mm

Clearance at SC is 0.7775mm

Clearance at SD is 2.885mm

Clearance at SE is 5.9973mm

Tabulating all the clearance values

Points	Clearance required (mm)	Clearance obtained (mm)	Result
SA	10	9.9490	Fail
SB	10	10	Pass
SC	10	0.777573	Fail
SD	10	2.885	Fail
SE	10	5.9973	Fail

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