Fender Design - Wheel Arch Challenge

AIM

Calculate the Wheel Arch gap at required points and check whether the car passes the European standard.

Wheel arch

Wheel arch is the semicircular part positioned above the wheel of vehicle to shield wheels, BIW and pedestrians from projection of water, mud,dirt, debris, sand, snow and stones. It also plays important role in safety of pedestrian and other passing by vehicles. Wheel arch is designed in such a way that wheels can turn both sides when steered without interference with body and gives access to wheel and other components attached to it.

Vehicle has to undergo many tests and fit into the criteria before into the market. For Wheel arch fender design also there are regulations set by each countries to check the gap between wheel and wheel arch. Most countries follows one of the standard regulations mentioned below:

Japanese Standard

• Sketch is created as shown in above figure.
• Measure clearance L of tire, hub, cap and fender in three different positions within area K and produce clearance check chart to validate
• Clearance must be greater than 5 mm in all three positions
• Wheel guard requirement: The value of 'a' shall be more than 5mm at a line 30 deg forward and 50 deg rearward from the central vertical axis of wheel.

European Standard

• Measure clearance L at sections SA-SA SB-SB SC-SC SE-SE and produce clearance check chart to validate
• At all five sections the clearance L value should be greater than 10mm to satisfy European regulations
• Wheel guard requirement: The value of 'a' shall be more than 5mm at a line 30 deg forward and 50 deg rearward from the central vertical axis of wheel.

US Standard

• Make clearance check details on all positions from -100 to 100 deg & mark the clearance check table
• All values should be greater than 5mm to satisfy the regulations
• Wheel guard requirement: The value of 'a' shall be more than 5mm at a line 30 deg forward and 50 deg rearward from the central vertical axis of wheel

In this challenge, we need to check gaps as per european standards for given data.

Procedure

1. To check the clearance a sketch is created as per European standard.
2. Datum plane is created on wheel face to create sketch. From center of wheel a vertical axis is drawn (SA). From this line 30deg forwrad and 50deg rareward lines are drawn. (SB-SC)
3. An offset of 150mm is created for horizontal line through center of wheel, a point is created where this offset line meets wheel arch line. Line is drawn from this point to wheel center. (SE)
4. Line SD is drawn by bisecting line SC and SE.
   
5. Now distance between these 5 lines and outer edge of fender curve is measured.
6. Similarly, clearance "a" is calculated at SB and SC line.

Results

1. Clearance "L"

Clearance L at SB=10mm

Clearance L at SA=9.95mm

Clearance L at SC=0.11mm

Clearance L at SD=2.88mm

Clearance L at SE=5.98mm

Table 1: Clearance "L"

Points	Minimum "L"(mm)	Observed "L"(mm)	Result	Mini Req "L"mm
SB	10	10.00	Pass	-
SA	10	9.95	Fail	0.1mm
SC	10	-0.11	Fail	10.12
SD	10	-2.88	Fail	12.88
SE	10	-5.98	Fail	15.98

2. Clearance "a"

Clearance "a" at SC=38.36mm

Clearance "a" at SB=43.63mm

Table 2: Clearance "a"

Points	Minimum "a"(mm)	Observed "a"(mm)	Result	Mini Req "a"mm
SB	5	43.63	Pass	-
SC	5	38.36	Pass	-

Conclusion

From above results, though results for clearance "a" passes the European Standards but, it does not pass the results for clearance "L" from table 1. It needs to be send back to the styling team to modify styling surface so clearance "L" is greater than 10mm at required points.

Hence from overall results, given car fender does not pass through the criteria given for the European standards for wheel arch.