Fender Design - Wheel Arch Challenge

Wheel Arc Challenge

Aim:

To calculate the Wheel Arch gap at required points and check whether the car passes the European

standard

Theory:

• 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 fender's openings for the wheel wells tend to be much larger than the diameter of the tire, because they do not move with the tire suspension and consequently must be large enough to allow the full range of tire motion on the suspension without touching the interior of the wheel well.

• 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.

Different 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 30degree forward and 50degree 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

US Regulations :

• Clearance "L" is to be checked at all positions from -100degree to 100degree 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

Calculation of wheel arch clearance using European Regulations:

For calculation of clearance between Wheel Arch and Wheel we have to create a sketch on the outer most 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 drawn 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

• calcuate the clearance "L" of the desired points

1) Clearance 'L' at SB-SB

2) Clearance 'L' at SA-SA

3)Clearance 'L' at SC-SC

4)Clearance 'L' at SD-SD

5)Clearance 'L' at SE-SE

Value of "a" for section SB-SB

Value of "a" for section SC-SC

Results:

Section	L (mm)	Result	a (mm)	Result
SA-SA	9.94	FAIL
SB-SB	10.00	PASS	43.88	PASS
SC-SC	0.11	FAIL	38.62	PASS
SD-SD	2.90	FAIL
SE-SE	5.96	FAIL

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.